| 1. |
- Klinge, Anna, et al.
(författare)
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Craniofacial height in relation to cross-sectional maxillary and mandibular morphology
- 2017
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Ingår i: Progress in Orthodontics. - : Springer. - 1723-7785 .- 2196-1042. ; 18:32
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Tidskriftsartikel (refereegranskat)abstract
- Background In order to gain a better understanding of how growth of the alveolar bone is linked to the vertical development of the face, the purpose of this study was to investigate if there is an association between the cross-sectional morphology of the maxillary and mandibular bodies with the craniofacial height, using images from cone beam computed tomography (CBCT). Methods From 450 pre-treatment CBCT scans, 180 were selected to be included in the study. Lateral head images were generated from the CBCT scans and were used to categorise subjects into three groups based on their vertical craniofacial height. Cross-sectional images from CBCT volumes were reformatted of the maxillary and mandibular bodies at five locations in the maxilla and five in the mandible. Each image was measured at one height and two width measurements. Statistical analysis performed was the one-way analysis of variance with a Tukey post hoc test. A significance level of 5% was used in all comparisons. Results Patients with large vertical craniofacial height had a significantly higher cross-sectional area both in the maxilla and in the mandible. In the same group, the cross-sectional area was significantly thinner in the mandible compared with the other two groups, especially in the anterior region. Conclusions This study further highlights the close relationship between craniofacial height and alveolar bone dimensions and contributes with important knowledge for planning and follow-up of comprehensive dental- and orthodontic treatments.
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| 2. |
- 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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| 3. |
- Bengtsson, Martin, et al.
(författare)
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Mandibular Access Osteotomy for Tumor Ablation : Could a More Tissue-Preserving Technique Affect Healing Outcome?
- 2016
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Ingår i: Journal of oral and maxillofacial surgery (Print). - : Elsevier. - 0278-2391 .- 1531-5053. ; 74:10, s. 2085-2092
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Paramedial mandibulotomy facilitates access for the resection of tumors in the oral and oropharyngeal space; however, severe complications related to surgical techniques and radiotherapy have been reported for this procedure. This study evaluated whether preservation of the periosteum during a mandibulotomy would decrease postoperative complications owing to the increased healing capacity provided by preserving more tissue. Materials and Methods: Patients who underwent mandibulotomy for surgical tumor ablation from 2007 through 2012 were included in a retrospective controlled cohort study. The trial was comprised of 2 groups: 1 group underwent subperiosteal and 1 group underwent supraperiosteal surgical dissection in the area of the mandibulotomy. The primary predictor variable was surgical technique and the primary outcome variable was surgical complications. The groups were matched according to tumor type, age, and gender. Clinical and radiographic follow-up was performed 12 months after surgery. Complications regarding bone exposure, plate exposure, osteoradionecrosis, nonunion, infection of the soft tissue flap, abscesses, fistulas, and gingival necrosis were recorded. Recordings of other factors, such as age, smoking habits, and timing of radiotherapy and chemotherapy, were performed and the 2 groups were compared for postoperative complications. Data analysis used the c2 test (Fisher exact test) to compare the sub- and supraperiosteal groups for postoperative complications. Results: Thirty-two patients were included (16 per group; 14 women and 18 men; mean age, 56 yr). Thir- teen patients in the subperiosteal group and 7 in the supraperiosteal group showed complications during the first 12 months. Seven patients had complications that persisted to the 12-month follow-up (6 in the subperiosteal group and 1 in the supraperiosteal group); however, the difference was not statistically relevant. Conclusion: This study found more persistent complications in the subperiosteal group compared with the supraperiosteal group at 12-month follow-up, which could imply that a more tissue-preserving surgical technique promotes mandibular healing in patients undergoing mandibular access osteotomy in combination with radiotherapy.
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| 4. |
- 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
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Ingår i: British Journal of Oral & Maxillofacial Surgery. - : Elsevier BV. - 0266-4356 .- 1532-1940. ; 57:4, s. 345-351
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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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| 5. |
- 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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| 6. |
- Hallmer, Fredrik, et al.
(författare)
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Bacterial diversity in medication-related osteonecrosis of the jaw
- 2017
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Ingår i: Oral surgery, oral medicine, oral pathology and oral radiology. - : Elsevier. - 2212-4403 .- 2212-4411. ; 123:4, s. 436-444
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The aim was to study the association between microflora and medication-related osteonecrosis of the jaw (MRONJ) by using culture-independent molecular techniques to detect bacteria in necrotic bone lesions. Study Design. Included were 18 consecutive patients with MRONJ, 10 with osteoporosis and 8 cancer patients. Bone biopsies were retrieved from the center of the necrotic bone and from visually healthy bone, and 16 S rRNA gene fragments from bacterial DNA were amplified with polymerase chain reaction. Results. The study revealed a diversity of bacteria represented by 16 S rRNA sequences in all the necrotic bone samples and in 60% of the visually healthy bone. Eight dominating taxa groups were identified at the genus level: Porphyromonas, Lactobacillus, Tannerella, Prevotella, Actinomyces, Treponema, Streptococcus, and Fusobacterium. Conclusions. The necrotic bone lesions contained mainly anaerobic bacteria, representative of periodontal microflora, suggesting that a periodontal infection in combination with antiresorptive treatment could initiate osteonecrosis.
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| 7. |
- Jinno, Yohei, et al.
(författare)
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Impact of salivary contamination during placement of implants with simultaneous bony augmentation in iliac bone in sheep
- 2019
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Ingår i: British Journal of Oral & Maxillofacial Surgery. - : Elsevier. - 0266-4356 .- 1532-1940. ; 57:10, s. 1131-1136
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Tidskriftsartikel (refereegranskat)abstract
- Our aim was to investigate the possible impact of contamination with saliva on osseointegration during placement of implants with simultaneous bone augmentation. Six hemispheric shape bone defects (8mm in diameter×4mm deep) were prepared in each iliac bone of six sheep. A dental implant (2.9mm in diameter×10mm long) was placed in the centre of each defect, and then pairs of defects were filled with one of the following bone augmentation materials: autogenous bone, autogenous bone plus bovine bone, or resorbable biphasic ceramic bone substitute. One site in each augmentation group was impregnated with saliva (contaminated group), while the other was not (non-contaminated group). Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) within implant threads were measured after a healing period of five weeks, both in respect of the implant inserted in the augmented bone and in that inserted in the residual bone. Overall results showed that there was a significant difference between the contaminated and non-contaminated group for BIC in the augmented implant (p=0.028), while there were no significant differences in the implant in residual bone (p=0.722). For BAFO, there were no significant differences between the contaminated and non-contaminated groups among the different augmentation materials. The results showed that contamination with saliva during placement of an implant with simultaneous bone augmentation had a serious deleterious effect on osseointegration of the aspect of the implant within the augmented defect. Contamination with saliva during placement of an implant with simultaneous bone augmentation should therefore be avoided.
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| 8. |
- Jinno, Yohei, et al.
(författare)
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Impact of surface contamination of implants with saliva during placement in augmented bone defects in sheep calvaria.
- 2019
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Ingår i: British Journal of Oral & Maxillofacial Surgery. - : Elsevier. - 0266-4356 .- 1532-1940. ; 57:1, s. 41-46
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Tidskriftsartikel (refereegranskat)abstract
- Our aim was to try and find out whether contamination with saliva during insertion of dental implants affects osseointegration in bone that has been augmented with different grafts. Six bony defects were created in each of the calvaria of six sheep, and then augmented with three different materials (autogenous bone, bovine bone, and resorbable biphasic ceramic bone substitute) After five weeks of healing, three implants contaminated with saliva (contaminated group) and three not contaminated (uncontaminated group) were placed in the centre of the augmented areas. For histomorphometric analysis, bone implant contact, bone area fraction occupancy, bone and material area, and bony area were measured after a healing period of five weeks. There was a significant difference between the contaminated and uncontaminated groups (p=0.036) for bone implant contact only in the augmented areas, but there were no significant differences in bone area fraction occupancy, bone and material area, and bony area. We conclude that contamination with saliva during placement of dental implants can significantly compromise bone implant contact in augmented areas, but had no significant effect on the formation of bone in areas more distant from the surface of the implant. We suggest that salivary contamination should be avoided during placement of dental implants in augmented areas.
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| 9. |
- Jinno, Yohei, et al.
(författare)
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Vertical Bone Augmentation Using Ring Technique with Three Different Materials in the Sheep Mandible Bone
- 2018
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Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence. - 0882-2786 .- 1942-4434. ; 33:5, s. 1057-1063
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this study was to examine the volumetric alterations and osseointegration properties in the augmented area of the ring technique using different types of bone graft material in sheep mandible bone. Materials and Methods: Three different materials (columnar forms, 7-mm diameter, 3-mm height) were stabilized using dental implants with a turned surface in the mandible bone of Finnish Dorset cross-bred sheep: group A, autogenous bone; group B, bovine bone; group C, biphasic bone substitute. Animals were euthanized after 5 weeks (N = 6). Three-dimensional image data by digital oral scanner were taken at the surgery and sacrifice, and the volume alteration of the material was calculated. The bone samples were fixed in formalin and dehydrated in ethanol. Resin-embedded samples were subjected to non-decalcified ground sectioning, and histologic and histomorphometric analysis (bone and material area alteration, bone-to-implant contact [BIC]) were done. Results: In three-dimensional (3D) image analysis, group A showed a statistically higher percentage of remaining materials compared with groups B and C. The histologic observation showed no new bone formations around the implants in all groups, especially at the maxillary site of the implant in the augmented area. In histomorphometric analysis, group A showed a statistically higher percentage of bone area (BA) compared with groups B and C; however, in all groups, bone-to-implant contact (BIC) showed low values, and there were no statistical differences between groups. Conclusion: The results of this study suggested that the autogenous bone maintained bone volume around the dental implant using the ring technique, and the impact of surface properties was of some importance; osseointegration with the turned surface in the augmented area showed low BIC values in all groups.
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| 10. |
- Johansson, Krister, et al.
(författare)
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Effects of Bacterial Contamination on Dental Implants During Surgery : A Systematic Review
- 2017
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Ingår i: Implant Dentistry. - : Lippincott Williams & Wilkins. - 1056-6163 .- 1538-2982. ; 26:5, s. 778-789
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Forskningsöversikt (refereegranskat)abstract
- INTRODUCTION: Contamination during surgery negatively influences the prognosis of orthopaedic implants; however, it has not been proven whether contamination influences the success of dental implant treatment. The aim of the systematic review was to investigate if there exists evidence in the literature whether contamination of dental implants during surgery affects osseointegration and clinical success. MATERIALS AND METHODS: Four data bases were used for the literature search. Primary studies and reviews regarding both clinical and preclinical research were eligible. Rating of the summarized quality of the evidence was performed. RESULTS: Five preclinical studies were included. Because of the estimated high risk of bias in all included studies and extensive differences in study design between the included studies, meta-analysis was not performed and no reliable aggregated data could be extracted. CONCLUSIONS: It is suggested that the scientific evidence with regard to the current topic is insufficient. Further controlled studies are warranted.
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| 11. |
- Lindström, Martin J R, et al.
(författare)
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Volumetric measurement of dentoalveolar defects by means of intraoral 3D scanner and gravimetric model
- 2019
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Ingår i: Odontology. - : Springer. - 1618-1247 .- 1618-1255. ; 103:3, s. 353-359
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the accuracy in volumetric measurements obtained on an experimental model using an intraoral scanner and a gravimetric method. Three identical partial dentate maxillary acrylic models with three fabricated alveolar defects, in anterior and posterior regions, were scanned using an intraoral scanner (20 scans/defects). The defects differed in terms of size and distance of neighbouring teeth. As references, replicas of each defect were created using a dimensional stable silicone impression material. After measuring the mass of each replica, the volume was calculated by dividing the mass of each replica by the density of the impression material. The defects had a volume, according to the gravimetric method, ranging from 40.5 to 143.7 mm. The scans were imported to metrology software for analyses. Accuracy was determined in terms of trueness and precision. The mean trueness for all defect types was 0.168 mm (SD 0.691, range 2.82). There was no statistical significant difference between the mean trueness for all defects measured (p = 0.910). The mean precision for all defect types was 0.147 mm (SD 0.524, range 2.86). There were no statistical significant differences between the dental models in regard to mean precision (p = 0.401), however, there were statistical significant differences between defects in position 1 and 2 (p = 0.002) and 1 and 3 (p = 0.001). Based on the findings of this study, the intraoral scanner utilized in the current study presented an acceptable level of accuracy when measuring volume of defects.
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| 12. |
- Starch-Jensen, Thomas, et al.
(författare)
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Maxillary Sinus Floor Augmentation With Synthetic Bone Substitutes Compared With Other Grafting Materials : A Systematic Review and Meta-analysis
- 2018
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Ingår i: Implant Dentistry. - : Lippincott Williams & Wilkins. - 1056-6163 .- 1538-2982. ; 27:3, s. 363-374
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Forskningsöversikt (refereegranskat)abstract
- Objective: To test the hypotheses of no differences in implant treatment outcome after maxillary sinus floor augmentation (MSFA) with synthetic bone substitutes (SBS) compared with other grafting materials applying the lateral window technique. Materials and Methods: A MEDLINE/PubMed, Embase and Cochrane Library search in combination with hand-search of selected journals was conducted. Results: Five randomized controlled trials with low risk of bias fulfilled the inclusion criteria. SBS disclosed high survival rate of suprastructures and implants with no significant differences compared to autogenous bone graft or xenograft. Meta-analysis revealed a patient-based implant survival rate of 0.98 (confidence interval: 0.89-1.08), indicating no differences between SBS and xenograft. SBS demonstrated significant less newly formed bone compared with autogenous bone graft, whereas no significant difference was revealed as compared to xenograft. High implant stability values, limited periimplant marginal bone loss, and few complications were reported with SBS. Conclusions: There seem to be no differences in implant treatment outcome after MSFA with SBS compared to other grafting materials.
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| 13. |
- Stocchero, Michele, et al.
(författare)
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Biomechanical, Biologic, and Clinical Outcomes of Undersized Implant Surgical Preparation : A Systematic Review
- 2016
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Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence. - 0882-2786 .- 1942-4434. ; 31:6, s. 1247-1263
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Forskningsöversikt (refereegranskat)abstract
- PURPOSE: To compile the current evidence on biomechanical, biologic, and clinical outcomes of undersized surgical preparation protocols in dental implant surgery. MATERIALS AND METHODS: An electronic search using three different databases (PubMed, Web of Science, and Cochrane Library) and a manual hand search were performed including in vitro, animal, and clinical studies published prior to October 2015. Studies in which an undersized drilling protocol was compared with a nonundersized drilling protocol were included. RESULTS: From an initial selection of 1,655 titles, 29 studies met the inclusion criteria, including 14 biomechanical, 7 biologic, 6 biologic and biomechanical, and 2 clinical. Due to methodologic variation, meta-analysis was not performed. Several studies showed that implants inserted with an undersized drilling approach reached a significantly higher insertion torque value than conventional drilling in low-density substrates, while this effect is less evident if a thick cortical layer is present. Similar results in terms of boneto-implant contact (BIC) were achieved in the longer term between implants inserted with undersized and nonundersized protocols. Results in the short term were inconclusive. Clinical studies did not show negative outcomes for undersized drilling, although clinical evidence was sparse. No data are available on marginal bone loss. CONCLUSION: From the biomechanical standpoint, an undersized drilling protocol is effective in increasing insertion torque in low-density bone. Biologic response in long-term healing after undersized implant placement is comparable to that in the nonundersized surgical drilling protocol. Clinical studies indicate that performing an undersized drilling protocol on low-density bone is a safe procedure; however, more extensive studies are needed to confirm these data.
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| 14. |
- Stocchero, Michele, et al.
(författare)
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Influence of different drilling preparation on cortical bone : A biomechanical, histological, and micro-CT study on sheep
- 2018
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 29:7, s. 707-715
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe aim of this study was to investigate the extent of cortical bone remodeling between two different drilling protocols by means of histomorphometric, mu-CT, and biomechanical analyses. Material and methodsA total of 48 implants were inserted into the mandible of six sheep following two drilling protocols: Group A (Test, n=24), undersized preparation; Group B (Control, n=24), non-undersized preparation. The animals were euthanatized to obtain 5 and 10weeks of implantation time. Removal torque (RTQ) was measured on 12 implants of each group and the peri-implant bone was mu-CT scanned. Bone volume density (BV/TV) was calculated in pre-determined cylindrical volumes, up to 1.5mm from implant surface. Non-decalcified histology was prepared on the remaining 12 implants from each group, where total bone-to-implant contact (totBIC) and newly-formed BIC (newBIC) was measured. Bone Area Fraction Occupancy (BAFO) was determined in pre-determined areas up to 1.5mm from implant surface. Paired sample t test or Wilcoxon signed-rank test was used to investigate differences between the groups. ResultsGroup A presented significantly increased RTQ value at 5weeks, while no difference was observed at 10weeks. Group B presented increased BV/TV value at 5weeks. Both groups showed comparable values for totBIC at both time-points. However, Group A presented significantly lower newBIC at 5weeks. Higher BAFO was observed in Group B at 5weeks. ConclusionsImplants inserted into undersized sites has an increased biomechanical performance, but provoked major remodeling of the cortical bone during the early healing period compared to non-undersized preparations. After 10weeks, no difference was observed.
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| 15. |
- Stocchero, Michele, et al.
(författare)
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Intraosseous Temperature Change during Installation of Dental Implants with Two Different Surfaces and Different Drilling Protocols : An In Vivo Study in Sheep
- 2019
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The intraosseous temperature during implant installation has never been evaluated in an in vivo controlled setup. The aims were to investigate the influence of a drilling protocol and implant surface on the intraosseous temperature during implant installation, to evaluate the influence of temperature increase on osseointegration and to calculate the heat distribution in cortical bone. METHODS: Forty Branemark implants were installed into the metatarsal bone of Finnish Dorset crossbred sheep according to two different drilling protocols (undersized/non-undersized) and two surfaces (moderately rough/turned). The intraosseous temperature was recorded, and Finite Element Model (FEM) was generated to understand the thermal behavior. Non-decalcified histology was carried out after five weeks of healing. The following osseointegration parameters were calculated: Bone-to-implant contact (BIC), Bone Area Fraction Occupancy (BAFO), and Bone Area Fraction Occupancy up to 1.5 mm (BA1.5). A multiple regression model was used to identify the influencing variables on the histomorphometric parameters. RESULTS: The temperature was affected by the drilling protocol, while no influence was demonstrated by the implant surface. BIC was positively influenced by the undersized drilling protocol and rough surface, BAFO was negatively influenced by the temperature rise, and BA1.5 was negatively influenced by the undersized drilling protocol. FEM showed that the temperature at the implant interface might exceed the limit for bone necrosis. CONCLUSION: The intraosseous temperature is greatly increased by an undersized drilling protocol but not from the implant surface. The temperature increase negatively affects the bone healing in the proximity of the implant. The undersized drilling protocol for Branemark implant systems increases the amount of bone at the interface, but it negatively impacts the bone far from the implant.
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| 16. |
- Toia, Marco, et al.
(författare)
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Effect of Misfit at Implant-Level Framework and Supporting Bone on Internal Connection Implants: Mechanical and Finite Element Analysis
- 2019
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Ingår i: International Journal of Oral & Maxillofacial Implants. - : Quintessence Publishing. - 0882-2786 .- 1942-4434. ; 34:2, s. 320-328
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the effect of misfit at implant-level fixed partial dentures (ILFPDs) and marginal bone support on the generation of implant cracks. Materials and Methods: This in vitro study included a mechanical fatigue test and finite element analysis. A mechanical cycling loading test was performed using 16 experimental models, each consisting of two parallel implants subdivided into four groups based on the misfit and the supporting bone condition. The framework, firmly seated at implants, was dynamically loaded vertically with a force of 1,600/160 N and 15 Hz for 1 x 10(6) cycles. Optical microscope, scanning electron microscope (SEM), and computed tomography three-dimensional (CT-3D) analyses were performed to detect impairments. Finite element models, representing the setups in the mechanical fatigue test, were used to represent the fatigue life. Results: None of the mechanical components presented distortion or fracture at the macroscopic level during the test. In a microscopy evaluation, the fatigue test revealed scratches visible in the inner part of the conical portion of the implants regardless of the groups. SEM and CT-3D analysis revealed one implant from the misfit/no bone loss group with a microfracture in the inner part of the conical interface. The simulated effective stress levels in the corona! body were higher in the misfit groups compared with the no misfit groups. The misfit groups presented effective stress levels, above 375 MPa, that penetrated the entire wall thickness. The no bone loss group presented an effective stress level above 375 MPa along its axial direction. In the no misfit group, the area presenting effective stress levels above 375 MPa in the conical connection was larger for the bone loss group compared with the no bone loss group. Conclusion: This study confirmed that implant fracture is an unlikely adverse event. A clear pattern of effective distribution greater than fatigue limit stresses could be noticed when the misfit was present. The dynamic load simulation demonstrated that the crack is more likely to occur when implants are fully supported by marginal bone compared with a bone loss scenario. Within the limitations of this study, it is speculated that marginal bone loss might follow the appearance of an undetected crack. Further research is needed to develop safe clinical protocols with regard to ILFPD.
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| 17. |
- Toia, Marco, et al.
(författare)
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Implant vs abutment level connection in implant supported screw-retained fixed partial dentures with cobalt-chrome framework: 1-year interim results of a randomized clinical study
- 2019
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Ingår i: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899 .- 1708-8208. ; 21:2, s. 238-246
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Tidskriftsartikel (refereegranskat)abstract
- Background Screw-retained fixed partial dentures (FPD) have shown a lower incidence of biologic complications and an easier retrievability compared with cemented FPD. Purpose To compare the marginal bone loss at conical connection implant restored with a screw retained cobalt-chrome FPD in an implant-level (IL) or an abutment-level (AL) setup. Materials and Methods Patients with at least two adjacent missing teeth were randomly allocated to be restored with IL or AL FPD. Periapical radiographs and clinical examination were taken at implant placement, prosthetic connection, 6 and 12 months to evaluate marginal bone loss (MBL), and soft tissue conditions. Complications were used to calculate prognostic indexes. Results Fifty patients were treated with 50 FPD supported by 119 implants. The difference of MBL between the IL and AL groups was statistically significant (P = 0.003). At 1 year, MBL was 0.086 +/- 0.313 mm and 0.005 +/- 0.222 mm in the IL and AL groups, respectively. The presence of BoP increased with time in IL, whereas it decreased in AL group (P < 0.001). A minor complication was encounted in one FPD. Conclusions A low grade of MBL was present after 1 year. IL showed greater amount of MBL and soft tissue inflammation indexes than AL. In FPD, AL may be a safer procedure than IL setup in order to preserve a healthy periimplant tissue.
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