| 1. |
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| 2. |
- Bidarian-Moniri, Armin, et al.
(författare)
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The effect of the prone sleeping position on obstructive sleep apnoea.
- 2015
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Ingår i: Acta oto-laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 135:1, s. 79-84
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Conclusions: Prone positioning reveals promising results in improving the apnoea-hypopnoea index (AHI) and oxygen desaturation index (ODI) in patients with obstructive sleep apnoea (OSA). Objective: To evaluate the effect of the prone position on OSA. Methods: Thirty-two patients with mild to severe OSA were included in the study. This was a two-night study to evaluate the effect of the prone position on OSA; a first night in a normal bed with optional positioning and a second night on a mattress and pillow facilitating prone positioning. Results: A total of 27 patients, 22 males and 5 females, with a mean age of 51 years, 15 patients with positional OSA (POSA) and 12 patients with non-POSA with a total median AHI of 23 (min 5, max 93) completed the study protocol. The median AHI decreased from 23 to 7 (p < 0.001) and the median ODI from 21 to 6 (p < 0.001). The median time spent in the supine position decreased from 142 to <1 min (p < 0.0001) and the median time in the prone position increased from <1 to 330 min (p < 0.0001). In all, 17 of 27 patients (63%) were considered to be responders to prone positioning, 12 of 15 (80%) with POSA and 5 of 12 (42%) with non-POSA. Five patients did not complete the study protocol due to sleep time <4 h.
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| 3. |
- Bjursten, Lars Magnus, et al.
(författare)
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Titanium dioxide nanotubes enhance bone bonding in vivo.
- 2010
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Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 92:3, s. 1218-24
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Tidskriftsartikel (refereegranskat)abstract
- Implant topography is critical to the clinical success of bone-anchored implants, yet little is known how nano-modified implant topography affects osseointegration. We investigate the in vivo bone bonding of two titanium implant surfaces: titanium dioxide (TiO(2)) nanotubes and TiO(2) gritblasted surfaces. In previous in vitro studies, the topography of the TiO(2) nanotubes improved osteoblast proliferation and adhesion compared with gritblasted titanium surfaces. After four weeks of implantation in rabbit tibias, pull-out testing indicated that TiO(2) nanotubes significantly improved bone bonding strength by as much as nine-fold compared with TiO(2) gritblasted surfaces. Histological analysis confirmed greater bone-implant contact area, new bone formation, and calcium and phosphorus levels on the nanotube surfaces. It is anticipated that further studies will contribute to a better understanding of the effect of implant nanotopography on in vivo bone formation and bonding strength.
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| 4. |
- Dasmah, Amir, et al.
(författare)
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A Clinical and Histological Case Series Study on Calcium Sulfate for Maxillary Sinus Floor Augmentation and Delayed Placement of Dental Implants
- 2012
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 14:2, s. 259-265
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Tidskriftsartikel (refereegranskat)abstract
- Background: Maxillary sinus floor augmentation is a procedure that is indicated in cases when the volume of the posterior maxillary bone is inadequate. The goal of this treatment is to obtain sufficient amount of bone tissue in order to gain osseointegration of endosseous implants. Purpose: The purpose of this study was to conduct a clinical and histological analysis of calcium sulfate (CaS) as bone graft substitute in sinus floor augmentation. Material and Methods: Ten patients with edentulous maxillas were included in this study. They had moderate to severe atrophy of the posterior maxilla. Surgiplaster (Classimplant(R), Rome, Italy) was used as graft material in the maxillary sinus and was covered by BioGide(R) (Geistlish Pharmaceutical, Wolhusen, Switzerland). After 4 months of graft healing, 40 dental implants were placed and a biopsy for histomorphometry was taken at these occasions. The specimens were viewed by light microscope, and the extent of bone regeneration and remaining graft material was evaluated. Radiographs were taken at the time of sinus augmentation and after 4 months of graft healing. Results: At the time of abutment surgery, one implant was considered as a failure and was consequently removed, giving a survival rate of 97.5% after 1 year of loading. Radiographs showed a mean of 26.5% shrinkage of the augmented area. A significant resorption of CaS was noted with a mean value of 8.8% of remaining graft material after 4 months of healing. The biopsies also revealed new bone formation with a mean value of 21.2% of the total biopsy area. Histology showed signs of an acellular substitution of CaS with bone-like tissue. Conclusion: The results of this study show that new bone regeneration occurs in the maxillary sinus after augmentation with CaS. This enabled successful placement, integration, and loading of dental implants in the posterior maxilla, as only 1 of 40 implants was lost during 1 year of follow-up.
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| 5. |
- Dasmah, Amir, et al.
(författare)
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Intramembraneous bone tissue responses to calcium sulfate : an experimental study in the rabbit maxilla
- 2011
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Ingår i: Clinical Oral Implants Research. - : Wiley. - 0905-7161 .- 1600-0501. ; 22:12, s. 1404-1408
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The purpose of this study was to histologically examine the responses of intramembraneous bone to calcium sulfate (CaS) and evaluate the resorption and replacement process. Material and methods: Fourteen rabbits were used in this study. Defect healing without any filling material was compared with CaS. Five millimetres wide and 4 mm deep defects were drilled with a trephine bur on both sides of the edentulous space between the incisors and the molars. Test vs. control sites were randomly selected and thereby compared in each animal. The animals were killed after 2, 4 and 8 weeks for histological examination. Results: After 2 weeks, the specimens showed a great extent of degradation of CaS. No signs of the material could be seen after 4 and 8 weeks. There were no statistically significant differences in bone regeneration between the test and control sites within the 8 weeks group in this study. However, there was tendency of more blood vessels in the test sites after 4 weeks of healing. Conclusion: The present study showed that CaS does not interfere with intramembraneous bone healing. In this animal model, the CaS exhibited resorption/degradation early in the healing process while seemingly stimulating angiogenesis. However, there was no significant increase in bone regeneration in the sites treated with CaS during an 8 week period of healing and observation time, as compared with a control defect.
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| 6. |
- Dasmah, Amir, et al.
(författare)
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Marginal Bone-Level Alterations at Implants Installed in Block versus Particulate Onlay Bone Grafts Mixed with Platelet-Rich Plasma in Atrophic Maxilla. A Prospective 5-Year Follow-Up Study of 15 Patients.
- 2013
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 15:1, s. 7-14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Extensive atrophy of the alveolar process may require a bone-grafting procedure prior to implant treatment. Autogenous bone grafts from the iliac crest, used as onlay block and particulate bone, have been used together with sinus-lift procedure in order to rehabilitate patients with extremely resorbed maxillae. However, there are to our knowledge no 5-year follow-up studies evaluating the extent of bone-level change in patients treated with respectively block and particulate autogenous bone grafts. Purpose: The purpose of this prospective clinical study was to conduct a 5-year follow-up analysis with focus on bone-level alteration in block versus particulate onlay bone grafts. Material and Methods: Fifteen out of originally 19 patients who were treated with iliac bone grafts and oral implants in the maxilla have been followed through the first 5 postoperative years. In a first study conducted on 19 patients, the role of platelet-rich plasma in conjunction with autogenous bone was evaluated. In this 5-year follow-up study, the marginal bone alterations have been documented at base line, 1 year and 5 years of loading to the nearest 0,1mm at mesial and distal surfaces of the implants. Two implants were installed on each side of the midline in either block or particulate bone grafts giving test and control sides in each patient. Additionally, two implants on each side were installed in residual bone/grafted sinus floor. Result: Marginal bone alteration in the anterior maxilla appeared larger at the side augmented by block bone at baseline, and after 1 and 5 years of loading, but the change was not statistically significant. Moreover, there was a significantly higher degree of marginal alteration during the first year of loading, compared with the examinations after 5 years. Conclusion: The present follow-up study showed that there is no significant difference in the extension of resorption between block- and particulate autogenous bone grafts over a 5-year period. Most of the resorption occurred during the first year in function.
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| 7. |
- Dasmah, Amir, et al.
(författare)
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Particulate vs. block bone grafts : Three-dimensional changes in graft volume after reconstruction of the atrophic maxilla, a 2-year radiographic follow-up
- 2012
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Ingår i: Journal of Cranio-Maxillofacial Surgery. - : Elsevier BV. - 1010-5182 .- 1878-4119. ; 40:8, s. 654-659
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Extensive alveolar bone resorption in the maxilla limits the possibility of successful placement and osseointegration of endosseous implants for future prosthetic rehabilitation. Autogenous bone from the iliac crest may be used as lateral onlays in the atrophic maxilla, both as block and particulate bone. To our knowledge, there is no three-dimensional 2-year follow-up study measuring the volumetric reduction of the augmented areas comparing particulate and block bone grafts.PURPOSE:The aim of this study was to conduct a radiographic 2-year follow-up study, using computed tomographic (CT) images in order to evaluate and compare the extent of bone graft resorption in the frontal maxillae augmented by particulate (test) and block bone (control).MATERIAL AND METHODS:Eleven patients treated with iliac bone grafts and oral implants in the maxilla were followed with CT examinations directly post grafting and after 2years.RESULT:The volumetric changes after 6months were extensive. Additionally, the changes in particulate bone tended to be larger after 2years compared to block bone, using this protocol. However, the difference was not statistically significant.CONCLUSION:The present follow-up study showed that there is radiographically complete integration and embedding of implants installed in grafted bone despite extensive initial graft resorption. There was no significant difference in the amount of volumetric reduction between particulate bone and block bone grafts.
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| 8. |
- Dasmah, Amir, et al.
(författare)
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Simultaneous or Delayed Placement of Surface Modified and Fluoridated Dental Implants into Autogenous Block Bone Grafts : A Histologic and Biomechanical Study in the Rabbit
- 2015
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 17:2, s. 395-401
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Tidskriftsartikel (refereegranskat)abstract
- Background: A delayed approach is recommended for reconstruction of the jaws with autogenous bone grafts and dental implants. Experimental studies have shown stronger bone tissue responses to surface modified implants than to nonmodified ones. AimThe aim of the study was to evaluate bone integration and stability of surface modified and fluoridated implants when placed with fresh or healed autogenous bone grafts. Material and Methods: Six rabbits were used in this study. Each right rabbit tibia (control) received an autogenous bone graft, harvested from the calvarium. Eight weeks later, a second graft was harvested from the other side of the calvarium and placed on the left tibia (test) with an implant. Another implant was installed in the healed graft of the right tibia. TiO2-blasted and fluoridated OsseoSpeed(TM) implants (Astra Tech AB, Molndal, Sweden), 3.5mm in diameter and 9mm long, were used. After additional 8 weeks, the rabbits were sacrificed and the implants were removed en bloc for light-microscopic analysis. Bone-to-implant contact (BIC) was registered as well as the amount of bone filling a rectangle indicating a region of interest (ROI). Resonance frequency analysis (RFA) was conducted both at the time of surgery and at the end of the experiment. ResultsThere were no statistically significant differences either in BIC or ROI between the test and control sides. RFA showed higher implant stability for the control side at the time of the surgery, but the difference had leveled out at the time of the sacrifice. Conclusion: The present study showed similar bone tissue responses and stability for surface modified and fluoridated implants after 8 weeks of healing in fresh or healed autogenous bone grafts.
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| 9. |
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| 10. |
- Lundgren, Stefan, et al.
(författare)
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Simultaneous or delayed placement of titanium implants in free autogenous iliac bone grafts. Histological analysis of the bone graft-titanium interface in 10 consecutive patients.
- 1999
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Ingår i: International journal of oral and maxillofacial surgery. - : Wiley. - 0901-5027 .- 1399-0020. ; 28:1, s. 31-7
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to histologically analyse the bone graft-titanium implant interface after six and twelve months of healing for a simultaneous approach and after six months for a delayed approach. For this purpose, screw-shaped c.p. titanium microimplants, 2 mm in diameter and 5 mm long, were placed and retrieved at different time intervals in ten consecutive patients with severely resorbed maxillae and treated with iliac cortico-cancellous bone grafts and titanium implants in a two-stage procedure. The histomorphometrical analyses of ground sections of the specimens showed a higher degree of bone-implant contact and more bone filling the implant threads in the delayed approach microimplants. This was probably due to the partly revascularized grafted bone in the delayed approach being able to respond to the surgical trauma, resulting in interfacial bone formation. It is concluded that the results from the present study favour the use of a delayed approach when using free autogenous bone grafts and titanium implants for reconstruction of the severely atrophied maxilla.
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| 11. |
- Lundgren, Stefan, et al.
(författare)
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Sinus floor elevation procedures to enable implant placement and integration: techniques, biological aspects and clinical outcomes
- 2017
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Ingår i: Periodontology 2000. - : Wiley. - 0906-6713 .- 1600-0757. ; 73:1, s. 103-120
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Forskningsöversikt (refereegranskat)abstract
- Implant treatment in an atrophied edentulous posterior maxilla constitutes a challenge for the therapeutic team. The authors of the present study acknowledge that modern micro-rough surface implants in lengths of about 8–10 mm or longer and of different brands are similarly successful. Consequently, the authors propose that the use of different sinus floor elevation techniques should be considered when < 8 mm of bone is available below the maxillary sinus. The type of sinus floor elevation technique selected is mainly based on residual vertical bone height, marginal bone width, local intrasinus anatomy and the number of teeth to be replaced, although other factors (such as surgical training and surgical experience) may have an impact. It is proposed that a transcrestal sinus floor elevation approach can be considered as a first-choice method for single tooth gaps in situations with sufficient width for implant placement and a residual bone height of 5–8 mm, while lateral sinus floor elevation, with or without grafting materials, is indicated when < 5 mm of bone is available and when several teeth are to be replaced. With regard to time of implant placement, a one-stage procedure is preferred provided that high primary stability can be ensured.
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| 12. |
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| 13. |
- Rasmusson, Lars, 1962, et al.
(författare)
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Measurements of stability changes of titanium implants with exposed threads subjected to barrier membrane induced bone augmentation. An experimental study in the rabbit tibia.
- 1997
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Ingår i: Clinical oral implants research. - : Wiley. - 0905-7161. ; 8:4, s. 316-22
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study was to evaluate in a rabbit model the changes in stability of implants that had been subjected to barrier membrane induced bone augmentation, as compared to untreated controls. One titanium implant was inserted in each proximal tibial metaphysis of 10 rabbits. The implants were placed in such a way that 4-5 threads on one side of the implant were left uncovered by bone. On the test side, the exposed implant surface was treated by means of a barrier membrane technique to provide for bone augmentation, while the contralateral side was untreated. The stability evaluations were made by means of resonance frequency measurements (RFM) at Day 0 and after 8, 16 and 24 weeks of healing. In addition, changes in the area of exposed implant threads were documented and measured on photographs. Removal torque measurements were performed at the day of sacrifice. In this study it was not possible to demonstrate a statistically significant better stability of implants subjected to barrier induced bone augmentation as compared to control implants still having exposed threads as evaluated by RFM and removal torque measurements.
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| 14. |
- Rasmusson, Lars, 1962, et al.
(författare)
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Morphological and dimensional changes after barrier removal in bone formed beyond the skeletal borders at titanium implants. A kinetic study in the rabbit tibia.
- 1997
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Ingår i: Clinical oral implants research. - : Wiley. - 0905-7161. ; 8:2, s. 103-16
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present experimental investigation was to study the morphological and dimensional changes of bone, augmented at titanium implants by a membrane technique, taking place after membrane removal. In 12 rabbits, screw-shaped titanium implants were inserted in the tibial metaphyses in such a way that 5 threads became uncovered with bone. Surgery was performed on 2 occasions in order to retrieve specimens with different follow-up times. An e-PTFE barrier and a titanium device were used to provide space for bone formation. In 1 tibia of each rabbit, the membranes and spacers were removed after 8 weeks of healing, and the implants followed for 16 more weeks. Impressions were taken at day 0 and after 8 and 24 weeks of healing and plaster models were produced. In the contralateral tibiae, implants were inserted either 16 or 8 weeks prior to sacrifice. Measurements were made on the plaster models in 3 dimensions at 35 points around each implant in a coordinate measuring machine. Specimens taken 8, 16 and 24 weeks after insertion were analysed by means of light microscopical morphometry. The coordinate measurements showed that, in mean, 1.92 mm of bone had been formed during the first 8 weeks. A statistically significant loss of the height of the newly formed bone (0.70 mm) and thereby reduction of bone volume was found 24 weeks postoperatively. The volume decrease of the newly formed bone was more pronounced beside the implants than over the implant body. The histology showed that woven bone had been formed at the implants after 8 weeks. Further bone formation and remodelling and a net increase of mineralized bone were seen. The degree of bone-implant contact and bone area in the threads increased with time. The present study showed that coordinate measurements on plaster models, obtained from the experimental areas, in combination with histology, form a useful technique to study long-term changes of augmented bone. It was found that bone formed by a barrier membrane technique, decreased in volume during a 16-week follow-up period after barrier removal. Less dimensional changes were observed for the bone formed over the implant body, indicating that a solid surface may have a stabilizing effect on the augmented bone.
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| 15. |
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| 16. |
- Rasmusson, Lars, 1962, et al.
(författare)
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Stability assessments and histology of titanium implants placed simultaneously with autogenous onlay bone in the rabbit tibia.
- 1998
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Ingår i: International journal of oral and maxillofacial surgery. - : Elsevier BV. - 0901-5027. ; 27:3, s. 229-35
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Tidskriftsartikel (refereegranskat)abstract
- A disc-shaped bone graft was harvested from the calvarium in ten rabbits and anchored as an onlay bone graft, using a titanium implant, at the proximal tibial metaphysis. The contralateral tibia served as the control, where an implant was placed without a graft with the implant head at a height corresponding to the thickness of the graft on the test side. Resonance frequency measurements were performed 4, 8, 16 and 24 weeks postoperatively and removal torque measurements were performed at 24 weeks. A statistically significant higher implant stability, as assessed by resonance frequency measurements (RFM), was measured from 4 weeks throughout the 24-week period. The mean peak removal torque for the test implants was 50.4+/-10.0 Ncm and 30.0+/-6.9 Ncm for the control implants, which was a statistically significant difference. Histologically, the grafted bone was well incorporated and morphometry revealed more bone around the test implants. Calculations of shear stresses indicated that the grafted bone had similar biomechanical properties to the cortical bone of the recipient site. It is concluded that the integration of titanium implants in autogenous onlay bone grafts results in an increased biomechanical support of the implant. The use of RFM may also serve as a useful instrument for noninvasive monitoring of implant stability in vivo.
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| 17. |
- Rasmusson, Lars, 1962, et al.
(författare)
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Stability Evaluation of Implants Integrated in Grafted and Nongrafted Maxillary Bone : a Clinical Study from Implant Placement to Abutment Connection
- 2012
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 14:1, s. 61-66
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Tidskriftsartikel (refereegranskat)abstract
- Background: Clinical studies have shown a higher degree of implant failures in grafted bone compared with normal nongrafted maxillary bone. Additionally, a prolonged time for integration of titanium implants in grafted block bone has been shown by means of resonance frequency analysis (RFA). Purpose: The aim of this prospective study was to compare the stability of implants placed in particulate bone, onlay block bone, interpositional bone, and nongrafted maxillary bone during the early phase of osseointegration using RFA and implant failure. Material and Methods: Thirty-five patients with edentulism in the maxilla were included in the study. In all, 260 Astra Tech TiOblast™ implants (Astra Tech AB, Mölndal, Sweden) were installed. Twenty-five of these patients had severe maxillary atrophy and were treated with iliac bone grafts 5 to 6 months prior to implant placement, 19 with lateral onlay block grafts on one side (group A, 38 implants) and particulate bone for lateral augmentation on the other (group B, 38 implants). These 19 patients also got bilateral sinus floor augmentation with particulate bone (group C, 76 implants). Six patients had an unfavorable sagittal relation between the jaws and underwent a LeFort I operation with interpositional bone blocks grafted to the nasal and sinus floors (group D, 48 implants). The remaining 10 patients could be treated with implants without bone augmentation and served as control (group E, 60 implants). RFA was performed at implant placement and abutment connection 6 months later and an implant stability quotient (ISQ) value was given for each implant. Results: Four implants (1.5%) were found mobile at abutment connection and removed (two in group A and two in group D). RFA showed a slight increase in stability from installation to abutment connection but the differences were not statistically significant in any of the groups (Wilcoxon signed rank test for comparison of paired data). Implants installed in group D had a significantly lower ISQ value at both measurements compared with the other groups (Wilcoxon Rank Sum test for comparisons of independent samples, p = .05). Conclusion: It is concluded that TiO(2) -blasted implants placed in nongrafted and grafted maxillary bone using a two-staged protocol show similar stability during the early phase of osseointegration. Patients reconstructed with interpositional bone graft after a LeFort I osteotomy showed lower implant stability values than nongrafted patients and other grafting techniques.
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| 18. |
- Rasmusson, Lars, 1962, et al.
(författare)
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The influence of simultaneous versus delayed placement on the stability of titanium implants in onlay bone grafts. A histologic and biomechanic study in the rabbit.
- 1999
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Ingår i: International journal of oral and maxillofacial surgery. - 0901-5027. ; 28:3, s. 224-31
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Tidskriftsartikel (refereegranskat)abstract
- A rabbit model was used to study the healing and stability of titanium implants in free bone grafts, placed simultaneously or after 8 weeks of healing and followed for 24 weeks. The skull bone was used as donor site and the tibial metaphysis as recipient site. Stability measurements were performed by using resonance frequency analysis (RFA) at implant placement and after 4, 8, 16 and 24 weeks of healing. Statistically significant higher resonance frequencies were measured at all time points for the delayed approach implants. Removal torque tests after 24 weeks revealed no differences between the two procedures. Histologic ground sections were prepared on specimens taken after 8, 16 and 24 weeks of healing. More bone-implant contacts were observed in the bone graft for the implants inserted in a delayed fashion, while there was no statistically significant difference in the degree of total bone-implant contact between the two groups. It is concluded that delayed implant placement in autogenous onlay bone grafts results in a better integration and stability of the implants.
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| 19. |
- Salata, L.A., et al.
(författare)
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Osseointegration of oxidized and turned implants in circumferential bone defects with and without adjunctive therapies: an experimental study on BMP-2 and autogenous bone graft in the dog mandible
- 2007
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Ingår i: INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY. - : Elsevier BV. - 0901-5027. ; 36:1, s. 62-71
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to compare the integration and implant stability of turned and oxidized titanium implants when placed in experimental bone defects with autogenous bone graft, BMP-2 or without adjunctive therapy. Four defects were prepared on each side of the mandible of 12 mongrel dogs five months after tooth extractions. Implants with turned and oxidized surfaces were placed in the defects. The circumferential gaps were filled with either autogenous bone grafts, a BMP-allogeneic dog mixture in a thermoplastic carrier, carrier alone or left without any treatment (control). There were no statistically significant differences between control and treated sites, neither for turned nor for oxidized implants with regard to histomorphometric measurements in ground sections and to implant stability as measured with resonance frequency analysis (RFA) after 4 and 12 weeks of healing. However, oxidized implants showed a significantly higher stability after 4 weeks and a tendency (p < 0.1) of that after 12 weeks. Histomorphometry showed more bone contacts for oxidized than for turned implants. It is concluded that oxidized implants gain stability more rapidly and integrate with more bone contacts than implants with a turned surface when placed in bone defects.
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| 20. |
- Sennerby, Lars, 1960, et al.
(författare)
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In memoriam.
- 2013
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 15:6
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 21. |
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| 22. |
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| 23. |
- Thor, Andreas Li, et al.
(författare)
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Correlation of Platelet Growth Factor Release in Jawbone Defect Repair - A Study in the Dog Mandible.
- 2013
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 15:5, s. 759-768
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Tidskriftsartikel (refereegranskat)abstract
- Background: Platelet concentrate/platelet-rich plasma (PRP) has been studied extensively in various experimental models and there is some agreement among workers to its early effect in bone regeneration and healing. We have earlier showed in vitro that titanium in whole blood activates the thrombogenic response to a higher degree than PRP and that a fluoridated test surface augmented the effect compared with control. Purpose: We designed this study to evaluate the effect of PRP and whole blood on bone regeneration in a dog implant defect model and, in addition, the effect of a test surface modified in hydrofluoric acid. A correlation attempt between platelet count, release of growth factors, and bone regeneration was made. Materials and Methods: Six dogs were used and simultaneously with the experimental surgery and implant installation, autologous PRP was prepared. Defects were prepared (6mm in diameter and 5mm deep), and implants were installed (TiO(2) gritblasted and hydrofluoric acid treated [test] or TiO(2) gritblasted [control], 5mm in diameter and 9mm long) in defects filled with either PRP or whole blood. Randomization of sides between PRP and whole blood, and sites for test and control implants were made. Blood samples were collected from PRP and whole blood. The dogs were killed after 5 weeks of healing, and samples with implants and surrounding bone were collected and processed for analysis. Enzyme linked immunosorbent assays were used for detection of growth factors in PRP. Results: The mean increase of platelet count was 424% in PRP. A correlation for platelet counts and transforming growth factor β was found in each dog (r(2) =0.857). Approximately 50% of the region of interest (ROI) in the defects was filled with new bone after 5 weeks. No difference could be observed in ROI by using PRP or whole blood in the defects regarding new bone formation, bone in contact with implant, or distance to first bone contact. However, the fluoridated implants exhibited more new bone formation (p=.03) compared with control, regardless of comparing PRP or whole blood, and also displayed a shorter distance from first bone contact to the margin of the bone envelope (p=.05). Conclusions: Platelet concentrate/PRP failed to show more new bone regeneration in a peri-implant defect model compared with whole blood. Implants treated with hydrofluoric acid displayed higher percentages of bone fill in the defect.
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| 24. |
- Thor, Andreas, et al.
(författare)
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Reconstruction of the severely resorbed maxilla with autogenous bone, platelet-rich plasma, and implants: 1-year results of a controlled prospective 5-year study.
- 2005
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Ingår i: Clinical implant dentistry and related research. - 1523-0899. ; 7:4, s. 209-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Prosthetic treatment of the edentulous maxilla may require bone augmentation to enable placement and integration of dental implants. This constitutes a complex healing situation, and resorption of the grafted bone and failure of the implants often occur. The application of autogenous platelet-rich plasma (PRP) has been suggested to improve incorporation and preservation of bone grafts. PURPOSE: The aim of this controlled clinical study was to evaluate whether PRP in conjunction with grafting of particulated autogenous bone to the maxilla could improve the integration and clinical function of dental implants. An additional aim was to compare block bone grafts without PRP with PRP-treated particulated bone. MATERIAL AND METHODS: Nineteen consecutive patients were included in the study and treated with iliac bone grafts and dental implants in the maxilla according to a split-mouth design. In the anterior maxilla, particulated bone mixed with PRP (test) was compared with onlay block grafts without additional PRP (control). In the posterior maxilla, particulated bone grafts with (test) or without (control) PRP were placed as sinus inlay grafts. After 6 months of healing, 152 implants (8 implants/patient) (TiOblast, Astra Tech AB, Mölndal, Sweden) were placed. Test (PRP; 76 implants) and non-PRP (76 implants) sides were evaluated and compared by implant survival rate, marginal bone level, and implant stability using resonance frequency analysis (RFA) during 1 year in function. RESULTS: Two control implants in control sites in two patients were lost at abutment connection. After 1 year in function, no further implants were lost, giving an overall survival rate of 98.7%. The marginal bone level measurements showed no significant differences, although there was a tendency toward less resorption on PRP sides. RFA measurements showed statistically significantly higher implant stability quotient values for PRP sites at abutment connection in the anterior but not in the posterior regions. CONCLUSIONS: The present clinical study showed that a high implant survival rate and stable marginal bone conditions can be achieved after 1 year of loading in the maxilla following autogenous bone grafting whether or not PRP is used. RFA measurements revealed differences at abutment connection, which could be explained by the type of graft rather than as an effect of PRP. Although no obvious positive effects of PRP on bone graft healing could be demonstrated, the handling of the particulated bone grafts was improved.
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| 25. |
- Zellin, Göran, 1962, et al.
(författare)
-
Evaluation of hemorrhage depressors on blood loss during orthognathic surgery: a retrospective study.
- 2004
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Ingår i: Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. - : Elsevier BV. - 0278-2391. ; 62:6, s. 662-6
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Correction of dentofacial deformities by orthognathic surgery may cause significant bleeding and therefore hypotensive anesthesia is often used to reduce the blood loss. The main objective of the present clinical study was to determine whether the addition of hemorrhage depressors to other medication during orthognathic surgery would further reduce the blood loss. PATIENTS AND METHODS: Thirty patients, consecutively operated on with standardized Le Fort I osteotomies in 1998 (n = 15, control group) and 1999 (n = 15, treatment group), were included in the study. Both groups received hypotension anesthesia during surgery and the treatment group received additional hemorrhage depressors; tranexamic acid and desmopressin. RESULTS: The mean blood loss was 740 +/- 410 mL (11.3 mL/kg) in the control group and 400 +/- 210 mL (5.7 mL/kg) in the treatment group. The results showed a statistically significant reduction of blood loss in the treatment group (P <.01). CONCLUSIONS: This study shows that blood loss during orthognathic surgery under hypotensive anesthesia can be significantly reduced when a combination of tranexamic acid and desmopressin is added.
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| 26. |
- Arruda, Thiago, et al.
(författare)
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Early healing in alveolar sockets grafted with titanium granules. An experimental study in a dog model.
- 2013
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Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 101A:7, s. 1971-1976
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to evaluate the effect of the placement of titanium granules in fresh extraction sockets on early bone formation. The mesial roots of the third maxillary premolars of five adult beagle dogs were removed. On one side of the maxilla (Test group) the fresh extraction socket was grafted with titanium granules, while the contra-lateral socket was left non-grafted (Control group). After 1 month of healing, the dogs were euthanized and biopsies were obtained. The healing tissues were described, and histometric measurements were performed to obtain the percentage area occupied by connective tissue, new mineralized bone, bone marrow, and biomaterial particles. After 1 month of healing the findings from the histological examination revealed the titanium graft to be well incorporated into the provisional connective tissue or newly formed woven bone. The histometric measurements showed, however, that less mineralized bone was formed in the Test group than in the Control group. The present study suggests that the use of titanium granules in fresh extraction sockets was conducive to new bone formation. The graft of titanium granules seems, however, to delay the early phase of the healing process. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
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| 27. |
- Bengtsson, M., et al.
(författare)
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A comparison of cost-effectiveness of computer-assisted 2-and 3-dimensional planning techniques in orthognathic surgery
- 2019
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Ingår i: British Journal of Oral & Maxillofacial Surgery. - : Elsevier BV. - 0266-4356 .- 1532-1940. ; 57:4, s. 352-358
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this randomised controlled trial was to compare the costs and benefits of computer-based 2-dimensional and 3-dimensional predictions in orthognathic surgery. Subjects aged 18-30 years with severe class III malocclusion had their treatment planned with both 2- and 3-dimensional techniques. They were randomised in a 1: 1 ratio for one or other planning technique. Costs (financial, time, and dose of radiation) were compared with benefits (accuracy and health-related quality of life (HRQoL)). In total, 57 subjects (27 women and 30 men, mean (range) age 21 (18-28) years) completed the study. Comparisons showed no significant difference in total time spent, but a large advantage for the 2-dimensional technique in financial costs (p < 0.001); it also required a significantly lower dose of radiation (p < 0.001). The cost-effectiveness analysis showed a reduction in time of 0.53 minutes/HRQoL-point gained, and an increased economic cost of US$15/HRQoL point gained for the 3-dimensional technique. It also showed that the two techniques consumed an equal amount of time, but that the 2-dimensional technique had lower financial costs, and the 3-dimensional technique a larger dose of radiation. (C) 2019 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
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| 28. |
- Bengtsson, M., et al.
(författare)
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Is there a difference in judgement of facial appearance depending on ethnic background? Photographic evaluation of facial appearance in orthognathic surgery
- 2020
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Ingår i: British Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0266-4356 .- 1532-1940. ; 58:7, s. 812-818
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Tidskriftsartikel (refereegranskat)abstract
- Is there a variation in facial ideals depending on ethnic background that affects judgements of outcome in orthognathic surgery? How does the evaluation correlate with patient-reported outcome measures? Two evaluation panels, Singaporean and Swedish, judged photographs of patients undergoing orthognathic surgery taken before and after operation. Improvement in facial aesthetics was calculated between the two ratings. The result was compared between the panels and correlated with health-related quality of life (QoL) measures. Thirty male and 27 female patients aged between 18 and 28 years (mean 21) were included, and 52 subjects were eligible for comparison of health-related QoL. The photographic evaluation showed that both panels judged there to be significant improvement in facial aesthetics after treatment (p < 0.001). The Singaporean panel rated the overall facial appearance higher than the Swedish panel when evaluating photographs both before (p = 0.025) and after (p = 0.032) operation. Improvement of the overall facial appearance showed no significant difference between the panels (p > 0.30). No correlation between health-related QoL and improvement of facial appearance was found by either panel. Subjective evaluation of facial aesthetics in orthognathic surgery is unaffected by the observer's ethnic origin. Independently of their ethnicity, the evaluation juries found that facial aesthetics improved after orthognathic surgery. Improvement reported by the juries corresponded to that reported by patients. © 2020 The British Association of Oral and Maxillofacial Surgeons
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| 29. |
- Bengtsson, M., et al.
(författare)
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Outcome of photographic evaluation of facial appearance in orthognathic surgery: how does it correlate with planning of treatment and patient-reported outcome?
- 2019
-
Ingår i: British Journal of Oral & Maxillofacial Surgery. - : Elsevier BV. - 0266-4356 .- 1532-1940. ; 57:4, s. 345-351
-
Tidskriftsartikel (refereegranskat)abstract
- The outcome of treatment in orthognathic surgery is dependent on preoperative surgical planning. The main purpose of the present study was to evaluate from photographs the improvement in facial appearance after orthognathic surgery. In addition, the outcomes of two different planning techniques, 2-dimensional and 3-dimensional, were compared and the correlation between the outcome and health-related quality of life (HRQoL) assessed. The study was a randomised controlled trial with the intervention being either 2-dimensional or 3-dimensional treatment planning. An evaluation panel compared photographs taken before and after operation on patients with severe class III malocclusion. The change in facial appearance was rated, the two planning techniques compared, and the result correlated with previously published findings on cephalometric accuracy and HRQoL in the same group. Completed 12-month follow-up resulted in the inclusion of 57 subjects aged between 18 and 28 years at the time of operation (mean 21 years). We found significant differences between the two evaluations (p = 4.4E-9) but no significant difference in facial improvement between the planning techniques (p = 0.54). However, there was a correlation between cephalometric measurement of accuracy in the anterior maxilla and evaluation of improvement of facial appearance (p = 0.024, r = 0.30), but we found no correlation + between HRQoL and the evaluation of facial appearance (p = 0.31, r = -0.14). We conclude that there was an improvement in facial aesthetics after orthognathic surgery that was independent of the planning technique used. (C) 2019 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
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| 30. |
- Bengtsson, M., et al.
(författare)
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Treatment outcome in orthognathic surgery - A prospective comparison of accuracy in computer assisted two and three-dimensional prediction techniques
- 2018
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Ingår i: Journal of Cranio-Maxillofacial Surgery. - : Elsevier BV. - 1010-5182. ; 46:11, s. 1867-1874
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of the present study was to assess the accuracy of two- and three-dimensional prediction techniques in orthognathic surgery. It was also a test of the very planning sequence. The scientific question was how well does the software support the surgeon in his way to find the perfect correction of the facial appearance while normalizing the occlusion? Thirty patients with a class III occlusion were included in this prospective study. Surgical planning with both techniques were undertaken for all patients. Surgery was performed according to the two-dimensional technique. The cephalometric measurements from two-dimensional and three dimensional predictions were compared with the postoperative results at the 12 months follow-up respectively. Together with an analysis of tracing error, placements of 2020 markers, 1860 measurements and 1280 comparisons was performed. The analysis showed an equally high accuracy for the studied techniques. The highest accuracy was found in the anterior maxilla. There was a tendency for an overestimation for the three-dimensional technique and an underestimation for the two-dimensional technique. Conclusions: The present study indicates an equal high accuracy in predicting facial outcome for both studied techniques. However, in those patients with asymmetric malocclusion and/or facial appearance the three-dimensional technique has an obvious advantage. (C) 2017 European Association for Cranio-Maxillo-Facial Surgery.
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| 31. |
- Bengtsson, Martin, et al.
(författare)
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Treatment outcome in orthognathic surgery-A prospective randomized blinded case-controlled comparison of planning accuracy in computer-assisted two- and three-dimensional planning techniques (part II)
- 2017
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Ingår i: Journal of Cranio-Maxillofacial Surgery. - : Elsevier BV. - 1010-5182. ; 45:9, s. 1419-1424
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of the present study was to compare the accuracy of two-dimensional (2D) and three-dimensional (3D) prediction methods. The hypothesis was that a 3D technique would give a more accurate outcome of the postoperative result. Material and methods: Patients with severe class III occlusion were included and planed with both a 2D and 3D prediction technique. They were there after randomly subdivided into a control (2D) and test (3D) group and treated according to the technique randomized for. Cephalometric measurements from 2D and 3D predictions were compared with 12-month follow-up respectively. Together with an analysis of tracing error, placements of 3580 cephalometric markers, 2460 measurements, 680 intra-individual analyses and 1200 preop/postop comparisons were performed in 57 individuals. Results: Statistically significant differences for accuracy between the two groups were seen for 11/NSL112/NSL2 and for A-A2 (p < 0.05). Both groups showed a high level of accuracy for SNA and SNB. The test group also showed a relatively high level of accuracy for 11/NSL and for the A-point. No prediction method achieves a perfect accuracy. As expected from this, measuring accuracy within each group showed statistically significant difference for all markers and cephalometric measurements (p < 0.001). Mandibular markers showed greater differences than maxillary markers. Conclusion: The present study indicates an equal high accuracy in predicting facial outcome for both studied techniques. However, in patients with asymmetry the three-dimensional technique has an obvious advantage. (C) 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
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| 32. |
- Bengtsson, Martin, et al.
(författare)
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Treatment outcomes and patient-reported quality of life after orthognathic surgery with computer-assisted 2-or 3-dimensional planning : A randomized double-blind active-controlled clinical trial
- 2018
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Ingår i: American Journal of Orthodontics and Dentofacial Orthopedics. - : Elsevier. - 0889-5406 .- 1097-6752. ; 153:6, s. 786-796
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Thorough treatment planning is essential for a good clinical outcome in orthognathic treatment. The planning is often digital. Both 2-dimensional (2D) and 3-dimensional (3D) software options are available. The aim of this randomized 2-arm parallel double-blinded active-controlled clinical trial was to comprae the outcomes of computer-based 2D and 3D planning techniques according to patient-reported health related quality of life. The hypothesis was that a 3D technique would give a better treatment outcome compared with a 2D technique. Methods: Orthognathic treatment for 62 subjects, aged 18 to 28 years, with severe Class III malocclusion was planned with both 2D and 3D techniques. After treatment planning but before surgery, the patients were randomly allocated via blind collection of 1 enveloped card for each subject in a 1:1 ratio to the test (3D) or the control (2D) group. Thus, the intervention was according to which planning technique was used. The primary outcome was patient-reported outcome measures. The secondary outcome was relationship between patient-reported outcome measures and cephalometric accuracy. Questionnaires on the patient's health-related quality of life (HRQoL) were distributed preoperatively and 12 months after surgical treatment. The questionnaires were coded, meaning blinding throughout the analysis. Differences between groups were tested with the Fisher permutation test. The HRQoL was also compared with measurements of cephalometric accuracy for the 2 groups. Results: Three subjects were lost to clinical follow-up leaving 57 included. Of these, 55 subjects completed the questionnaires, 28 in the 2D and 27 in the 3D groups. No statistically significant difference regarding HRQoL was found between the studied planning techniques: the Oral Health Impact Profile total showed -3.69 (95% confidence interval, -19.68 to 12.30). Consistent results on HRQoL and cephalometric accuracy showed a difference between pretreatment and postreatment that increased in both groups but to a higher level in the 3D group. A difference between pretreatment and posttreatment HRQoL was shown for both groups, indicating increased quality of life after treatment. This supports recent findings comparing 3D and 2D planning techniques. No serious harm was observed during the study. Conclusions: Improvements of HRQoL were shown after treatment independent of which planning technique, 2D or 3D, was used. No statistically significant difference was found between the planning techniques. Registration: This trial was not registered. Protocol: The protocol was not published before trial commencement.
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| 33. |
- Boffano, P., et al.
(författare)
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The epidemiology and management of ameloblastomas: A European multicenter study
- 2021
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Ingår i: Journal of Cranio-Maxillofacial Surgery. - : Elsevier BV. - 1010-5182. ; 49:12, s. 1107-1112
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Tidskriftsartikel (refereegranskat)abstract
- The present study aimed at assessing the epidemiology including demographic variables, diagnostic features, and management of ameloblastomas at several European departments of maxillofacial and oral surgery. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, type, histopathological features, kind of treatment, length of hospital stay, complications, recurrence, management and complications of the recurrence. A total of 244 patients, 134 males and 110 females with ameloblastomas were included in the study. Mean age was 47.4 years. In all, 81% of lesions were found in the mandible, whereas 19% were found in the maxilla. Mean size of included ameloblastomas was 38.9 mm. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 94 ameloblastomas, followed by segmental resection (60 patients), simple enucleation (46 patients), and marginal resection (40 pa-tients). A recurrence (with a mean follow up of 5 years) was observed in 47 cases out of 244 ameloblastomas (19.3%). Segmental resection was associated with a low risk of recurrence (p = 0003), whereas enucleation plus curettage/peripheral ostectomy was associated with a high risk of recurrence (p = 0002). A multilocular radiographic appearance was associated with a high risk of recurrence (p < .05), as well as the benign solid/multicystic histologic type (p < .05). Within the limitations of the study it seems that the management of ameloblastomas will probably remain controversial even in the future. Balancing low surgical morbidity with a low recurrence rate is a difficult aim to reach. (c) 2021 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
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| 34. |
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| 35. |
- Bystedt, Hans, et al.
(författare)
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Porous titanium granules used as osteoconductive material for sinus floor augmentation: a clinical pilot study.
- 2009
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 11:2, s. 101-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Resorption of grafting material may lead to unpredictable long-term results when rehabilitating the resorbed posterior maxilla. Nonresorbable, osteoconductive bone substitutes may therefore be an advantage over autogenous bone grafts. PURPOSE: The aim of the present pilot study was to test titanium granules as bone substitute in patients planned for augmentation of the sinus floor prior to or in conjunction with placement of dental implants. MATERIALS AND METHODS: Sixteen patients with uni- or bilateral edentulism and need for augmentation of the sinus floor were included in the study. Residual bone height was 2 to 5 mm. Grafting and installation of the dental implants (18 fixtures) was carried out in the same session if primary stability of the implants could be achieved (12 patients). A staged protocol with implant placement 3 to 7 months after the augmentation procedure was used when primary implant stability was impossible to achieve (four patients). In all, 23 TiOblast (Astra Tech AB, Mölndal, Sweden) implants were installed. RESULTS: The patients have been followed 12 to 36 months after prosthetic loading. Three implants were found mobile and were removed (13.0%). Two of these were in patients where grafting and implant installation were carried out in separate procedures. The implants were found mobile at abutment connection and were removed. One patient in the single-stage group had a postoperative sinus infection, which was successfully treated with antibiotics. However, one out of two implants in this patient was found mobile and was removed after 1 year in function. CONCLUSIONS: In the present study, titanium granules seem to function as augmentation material in the sinus floor. It is, however, not clear if the material can be safely used for two-stage procedures. Further investigations with longer healing time before implant installation are required. Also, the possible risk of granule displacement during preparation of the fixture site should be further investigated. Additionally, biopsies from patients are requested to confirm any bone ingrowth between the granules.
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| 36. |
- Dasmah, Amir, et al.
(författare)
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Integration of fluoridated implants in onlay autogenous bone grafts - An experimental study in the rabbit tibia.
- 2014
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Ingår i: Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery. - : Elsevier BV. - 1878-4119 .- 1010-5182. ; 42:6, s. 796-800
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Tidskriftsartikel (refereegranskat)abstract
- Bone augmentation before treatment with endosseous implants is a common procedure for rehabilitation of the edentulous jaw. Both machined and surface modified implants have been used in one-stage and two-stage surgery protocols with varying results and survival rates. The influence of surface modification on the integration of implants has been documented in both non-grafted and grafted bone. The aim of this study was to compare the integration and stability of surface modified fluoridated vs. machined implants when placed simultaneously with an onlay bone graft.
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| 37. |
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| 38. |
- Ehrenfest, D. M. D., et al.
(författare)
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In Search of a Consensus Terminology in the Field of Platelet Concentrates for Surgical Use: Platelet-Rich Plasma (PRP), Platelet-Rich Fibrin (PRF), Fibrin Gel Polymerization and Leukocytes
- 2012
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Ingår i: Current Pharmaceutical Biotechnology. - 1389-2010. ; 13:7, s. 1131-1137
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Tidskriftsartikel (refereegranskat)abstract
- In the field of platelet concentrates for surgical use, most products are termed Platelet-Rich Plasma (PRP). Unfortunately, this term is very general and incomplete, leading to many confusions in the scientific database. In this article, a panel of experts discusses this issue and proposes an accurate and simple terminology system for platelet concentrates for surgical use. Four main categories of products can be easily defined, depending on their leukocyte content and fibrin architecture: Pure Platelet-Rich Plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; Leukocyte- and Platelet-Rich Plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan, Angel or GPS PRP; Pure Plaletet-Rich Fibrin (P-PRF), such as Fibrinet; and Leukocyte-and Platelet-Rich Fibrin (L-PRF), such as Choukroun's PRF. P-PRP and L-PRP refer to the unactivated liquid form of these products, their activated versions being respectively named P-PRP gels and L-PRP gels. The purpose of this search for a terminology consensus is to plead for a more serious characterization of these products. Researchers have to be aware of the complex nature of these living biomaterials, in order to avoid misunderstandings and erroneous conclusions. Understanding the biomaterials or believing in the magic of growth factors ? From this choice depends the future of the field.
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| 39. |
- Faria, Paulo E P, et al.
(författare)
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Effects of early functional loading on maintenance of free autogenous bone graft and implant osseointegration: an experimental study in dogs.
- 2010
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Ingår i: Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. - : Elsevier BV. - 1531-5053. ; 68:4, s. 825-32
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim of the present study was to investigate the healing, integration, and maintenance of autogenous onlay bone grafts and implant osseointegration either loaded in the early or the delayed stages. MATERIALS AND METHODS: A total of 5 male dogs received bilateral blocks of onlay bone grafts harvested from the contralateral alveolar ridge of the mandible. On one side, the bone block was secured by 3 dental implants (3.5 mm x 13.0 mm, Osseospeed; AstraTech AB, Mölndal, Sweden). Two implants at the extremities of the graft were loaded 2 days after installation by abutment connection and prosthesis (simultaneous implant placement group); the implant in the middle remained unloaded and served as the control. On the other side, the block was fixed with 2 fixation screws inserted in the extremities of the graft. Four weeks later, the fixation screws were replaced with 3 dental implants. The loading procedure (delayed implant placement group) was performed 2 days later, as described for the simultaneous implant placement sites. The animals were sacrificed 12 weeks after the grafting procedure. Implant stability was measured through resonance frequency analysis. The bone volume and density were assessed on computed tomography. The bone to implant contact and bone area in a region of interest were evaluated on histologic slides. RESULTS: The implant stability quotient showed statistical significance in favor of the delayed loaded grafts (P = .001). The bone-to-implant contact (P = .008) and bone area in a region of interest (P = 0.005) were significantly greater in the delayed group. Nevertheless, no difference was found in terms of graft volume and density between the early loaded and delayed-loaded approaches. CONCLUSIONS: The protocol in which the implant and bone graft were given delayed loading allows for effective quality of implant osseointegration and stabilization, with healing and remodeling occurring in areas near the implant resulting in denser bone architecture.
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| 40. |
- Faria, Paulo Esteves Pinto, et al.
(författare)
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Immediate loading of implants in the edentulous mandible: a multicentre study.
- 2016
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Ingår i: Oral and maxillofacial surgery. - : Springer Science and Business Media LLC. - 1865-1569 .- 1865-1550. ; 20:4, s. 385-390
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this prospective study was to investigate the two-year outcomes following immediate loading of mono-cortically engaged implants.Thirty healthy mandible edentulous patients with an average age of 67.3years and presenting with sufficient bony ridge at the mandible symphysis were included in the study. Four Astra Tech, Ti-Oblast(®) implants were installed between the mental foramina using the mono-cortical anchorage technique. The primary stability of the implants was assessed by resonance frequency analysis (RFA). After uni-abutments were placed, a temporary bridge was constructed and fixed the same day. The definitive bridges were installed 6weeks after implant surgery. Five of 120 placed implants were lost in four patients during the first 6weeks and these patients were excluded from the follow-up. The changes in marginal bone level (n=20) were evaluated in Brazilian and Swedish groups at baseline, 6weeks, 6months, 12months and 24months. The RFA (n=30) was evaluated at baseline, 6weeks, 6months, 12months and 24months postoperatively.Compared with baseline measurements, the postoperative values for marginal bone level (6weeks, 6months, 12months and 24months) were significantly reduced (p<0.05), while no differences were observed in the RFA analysis (12months and 24months).The immediate loading of mono-cortically engaged implants in the edentulous mandible is safe and predictable and implant stability remains excellent after 2-year follow-up.
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| 41. |
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| 42. |
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| 43. |
- Kahnberg, Karl-Erik, 1941, et al.
(författare)
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Local Sinus Lift for Single-Tooth Implant. I. Clinical and Radiographic Follow-Up.
- 2011
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1708-8208 .- 1523-0899. ; 13:3, s. 231-137
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT Background: For single-tooth implant replacement in the posterior maxilla, it is often necessary to do an augmentation of the alveolar process because of post-extraction resorption and include part of the maxillary sinus. Purpose: The purpose of this study is to present a technique for a local sinus lift with autogenous bone in a one-stage procedure. Additionally, volume changes of the grafted area were evaluated radiographically up to 2 years. Materials and Methods: Twenty patients, 12 female and 8 males, were included in the study. Single-tooth replacement was made in the second premolar area in 7 cases and in the molar area in 13 cases. Local sinus lift and implant installation were made simultaneously. Abutment connection was made after 6 months of healing. Results: Two years of clinical and radiographic follow-ups have been made in all patients. The survival rate was 100%. The residual bone volume in the actual area was 2-5 mm preoperatively, after sinus lifting in mean 13 mm, after 1 year in mean 11.4 mm, and 2 years postoperatively in mean 10.6 mm. Conclusions: Local sinus lift with simultaneous bone augmentation and single-tooth replacement in the posterior maxilla is a predictable method although a certain bone volume reduction around the implant was evident at the 2-year follow-up.
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| 44. |
- Karazisis, Dimitrios, 1977, et al.
(författare)
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Molecular Response to Nanopatterned Implants in the Human Jaw Bone
- 2021
-
Ingår i: Acs Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 7:12, s. 5878-5889
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Tidskriftsartikel (refereegranskat)abstract
- Implant surface modification by nanopatterning is an interesting route for enhancing osseointegration in humans. Herein, the molecular response to an intentional, controlled nanotopography pattern superimposed on screw-shaped titanium implants is investigated in human bone. When clinical implants are installed, additional two mini-implants, one with a machined surface (M) and one with a machined surface superimposed with a hemispherical nanopattern (MN), are installed in the posterior maxilla. In the second-stage surgery, after 6-8 weeks, the mini-implants are retrieved by unscrewing, and the implant-adherent cells are subjected to gene expression analysis using quantitative polymerase chain reaction (qPCR). Compared to those adherent to the machined (M) implants, the cells adherent to the nanopatterned (MN) implants demonstrate significant upregulation (1.8- to 2-fold) of bone-related genes (RUNX2, ALP, and OC). No significant differences are observed in the expression of the analyzed inflammatory and remodeling genes. Correlation analysis reveals that older patient age is associated with increased expression of proinflammatory cytokines (TNF-alpha and MCP-1) on the machined implants and decreased expression of proosteogenic factor (BMP-2) on the nanopatterned implants. Controlled nanotopography, in the form of hemispherical 60 nm protrusions, promotes gene expressions related to early osteogenic differentiation and osteoblastic activity in implant-adherent cells in the human jaw bone.
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| 45. |
- Karazisis, Dimitrios, 1977, et al.
(författare)
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The effects of controlled nanotopography, machined topography and their combination on molecular activities, bone formation and biomechanical stability during osseointegration
- 2021
-
Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 136, s. 279-290
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Tidskriftsartikel (refereegranskat)abstract
- The initial cellular and molecular activities at the bone interface of implants with controlled nanoscale topography and microscale roughness have previously been reported. However, the effects of such surface modifications on the development of osseointegration have not yet been determined. This study investigated the molecular events and the histological and biomechanical development of the bone interface in implants with nanoscale topography, microscale roughness or a combination of both. Polished and machined titanium implants with and without controlled nanopatterning (75 nm protrusions) were produced using colloidal lithography and coated with a thin titanium layer to unify the chemistry. The implants were inserted in rat tibiae and subjected to removal torque (RTQ) measurements, molecular analyses and histological analyses after 6, 21 and 28 days. The results showed that nanotopography superimposed on microrough, machined, surfaces promoted an early increase in RTQ and hence produced greater implant stability at 6 and 21 days. Two-way MANOVA revealed that the increased RTQ was influenced by microscale roughness and the combination of nanoscale and microscale topographies. Furthermore, increased bone-implant contact (BIC) was observed with the combined nanopatterned machined surface, although MANOVA results implied that the increased BIC was mainly dependent on microscale roughness. At the molecular level, the nanotopography, per se, and in synergy with microscale roughness, downregulated the expression of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In conclusion, controlled nanotopography superimposed on microrough machined implants promoted implant stability during osseointegration. Nanoscale-driven mechanisms may involve attenuation of the inflammatory response at the titanium implant site. Statement of Significance: The role of combined implant microscale and nanotopography features for osseointegration is incompletely understood. Using colloidal lithography technique, we created an ordered nanotopography pattern superimposed on screwshaped implants with microscale topography. The midterm and late molecular, bone-implant contact and removal torque responses were analysed in vivo. Nanotopography superimposed on microrough, machined, surfaces promoted the implant stability, influenced by microscale topography and the combination of nanoscale and microscale topographies. Increased bone-implant contact was mainly dependent on microscale roughness whereas the nanotopography, per se, and in synergy with microscale roughness, attenuated the proinflammatory tumor necrosis factor alpha (TNF-α) expression. It is concluded that microscale and nanopatterns provide individual as well as synergistic effects on molecular, morphological and biomechanical implant-tissue processes in vivo.
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| 46. |
- Karazisis, Dimitrios, 1977, et al.
(författare)
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The influence of controlled surface nanotopography on the early biological events of osseointegration
- 2017
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 53, s. 559-571
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Tidskriftsartikel (refereegranskat)abstract
- The early cell and tissue interactions with nanopatterned titanium implants are insufficiently described in vivo. A limitation has been to transfer a pre-determined, well-controlled nanotopography to 3D titanium implants, without affecting other surface parameters, including surface microtopography and chemistry. This in vivo study aimed to investigate the early cellular and molecular events at the bone interface with screw-shaped titanium implants superimposed with controlled nanotopography. Polished and machined titanium implants were firstly patterned with 75-nm semispherical protrusions. Polished and machined implants without nano-patterns were designated as controls. Thereafter, all nanopatterned and control implants were sputter-coated with a 30 nm titanium layer to unify the surface chemistry. The implants were inserted in rat tibiae and samples were harvested after 12 h,1 d and 3 d. In one group, the implants were unscrewed and the implant-adherent cells were analyzed using quantitative polymerase chain reaction. In another group, implants with surrounding bone were harvested en bloc for histology and immunohistochemistry. The results showed that nanotopography downregulated the expression of monocyte chemoattractant protein-1 (MCP-1), at 1 d, and triggered the expression of osteocalcin (DC) at 3 d. This was in parallel with a relatively lower number of recruited CD68-positive macrophages in the tissue surrounding the nanopatterned implants. Moreover, a higher proportion of newly formed osteoid and woven bone was found at the nanopatterned implants at 3 d. It is concluded that nanotopography, per se, attenuates the inflammatory process and enhances the osteogenic response during the early phase of osseointegration. This nanotopography-induced effect appeared to be independent of the underlying microscale topography. This study provides a first line of evidence that pre-determined nanopatterns on clinically relevant, screw-shaped, titanium implants can be recognized by cells in the complex in vivo environment. Until now, most of the knowledge relating to cell interactions with nanopatterned surfaces has been acquired from in vitro studies involving mostly two-dimensional nanopatterned surfaces of varying chemical composition. We have managed to superimpose pre-determined nanoscale topography on polished and micro-rough, screw-shaped, implants, without changes in the microscale topography or chemistry. This was achieved by colloidal lithography in combination with a thin titanium film coating on top of both nanopatterned and control implants. The early events of osseointegration were evaluated at the bone interface to these implants. The results revealed that nanotopography, as such, elicits downregulatory effects on the early recruitment and activity of inflammatory cells while enhancing osteogenic activity and woven bone formation. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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| 47. |
- Kashani, Hossein, et al.
(författare)
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Osteotomies in Orthognathic Surgery
- 2016
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Ingår i: A Textbook of Advanced Oral and Maxillofacial Surgery, Vol. 3. Mohammad Hosein Kalantar Motamedi (red.). - : INTECH. - 9789535125914 ; , s. 617-649
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Bokkapitel (refereegranskat)
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| 48. |
- Lyngstadaas, S. P., et al.
(författare)
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Titanium Granules for Augmentation of the Maxillary Sinus - A Multicenter Study
- 2015
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundBiomaterials are commonly used to augment the maxillary sinus floor prior to or in conjunction with dental implant installation. Recently, porous titanium granules (PTGs) have been used in oral implant surgery to stabilize implants and function as an osteoconductive matrix. PurposeTo evaluate if PTGs can be safely used in a larger population of patients, treated by different surgeons, when sinus floor augmentation was required in conjunction with implant installation. The primary endpoint was 12-month survival rate of the dental implants. Biopsies for histology were taken from the augmented area. Materials and MethodsAt five centers, 40 subjects with uni or bilateral posterior edentulism and atrophy of the posterior maxilla (3-6mm) were enrolled. In a single-stage procedure, PTG and one to three dental implants were installed in each quadrant. In total, 70 implants were included in the study. ResultsOne immobile implant was removed. The mean marginal bone loss was 0.5mm and 0.8mm, on the mesial and distal side, respectively. Histologically, all biopsies demonstrated bone ingrowth. ConclusionsThe results suggest that PTG can be safely and effectively used as augmentation material in the sinus floor when used with dental implants in a one-stage procedure.
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| 49. |
- Merheb, J., et al.
(författare)
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Influence of Skeletal and Local Bone Density on Dental Implant Stability in Patients with Osteoporosis
- 2016
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 18:2, s. 253-260
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Tidskriftsartikel (refereegranskat)abstract
- Background and PurposeOsteoporosis is a major skeletal disease affecting millions of people worldwide. Recent studies claim that patients with osteoporosis do not have a higher risk of early implant failure compared to non-osteoporotic patients. The aim of this study was to assess the effect of skeletal osteoporosis and local bone density on initial dental implant stability. Materials and MethodsSeventy-three patients were recruited and were assigned (based on a Dual-energy X-ray Absorptiometry scan) to either the osteoporosis (Opr), osteopenia (Opn), or control (C) group. Forty nine of the 73 patients received dental implants and had implant stability measured by means of resonance frequency analysis (RFA) at implant placement and at prosthetic abutment placement. On the computerized tomography scans, the cortical thickness and the bone density (Hounsfield Units) at the sites of implant placement were measured. ResultsAt implant placement, primary stability was on average lower in group Opr (63.310.3 ISQ) than in group Opn (65.3 +/- 7.5 implant stability qutient (ISQ)), and group C (66.7 +/- 8.7 ISQ). At abutment placement, a similar trend was observed: group Opr (66.4 +/- 9.5 ISQ) scored lower than group Opn (70.7 +/- 7.8 ISQ), while the highest average was for group C (72.2 +/- 7.2 ISQ). The difference between groups Opr and C was significant. Implant length and diameter did not have a significant effect on implant stability as measured with RFA. A significant correlation was found between local bone density and implant stability for all regions of interest. ConclusionsImplant stability seems to be influenced by both local and skeletal bone densities. The lower stability scores in patient with skeletal osteoporosis reinforce the recommendations that safe protocols and longer healing times could be recommended when treating those patients with dental implants.
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| 50. |
- Merheb, J., et al.
(författare)
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Relation between Spongy Bone Density in the Maxilla and Skeletal Bone Density
- 2015
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 17:6, s. 1180-1187
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Tidskriftsartikel (refereegranskat)abstract
- © 2015 Wiley Periodicals, Inc. Background and Purpose: Osteoporosis is a disease affecting more than 300 million people worldwide and is responsible for numerous medical complications. This study aimed to investigate the relation between skeletal and maxillary bone density. Materials and Methods: Seventy-three patients were recruited and divided between group A (osteoporosis), group B (healthy, control), and group C (osteopenia) on the basis of a dual-energy x-ray absorptiomery (DXA) scan. These patients also received a CT scan on which bone density measurements were performed at five sites: maxilla midline, retromolar tuberosities, incisor, premolars, and molar regions. Results: The bone density was lower in osteoporotic patients compared with the control patients. The bone mineral density (BMD) of the tuberosities showed the strongest correlations with the BMD of the hip and the spine (respectively, r=0.50 and r=0.61). The midline region showed moderate correlations with the hip (r=0.47) and the spine (r=0.46). For potential implant sites, the correlations with the BMD of the hip and spine were, however, small to insignificant. Based on measurements of bone density of the maxilla, it was possible to predict if the patient was osteoporotic or not with a sensitivity of 65% and a specificity of 83%. Conclusions: The maxillary bone density of subjects with osteoporosis is significantly lower than that of healthy patients. Moreover, there is a direct correlation between the density of the skeleton and the density of some sites of the maxilla. Using measurements of maxillary bone density in order to predict skeletal bone density might be a useful tool for the screening of osteoporosis.
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