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| 2. |
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| 3. |
- Hallman, Mats, et al.
(författare)
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Bone substitutes and growth factors as an alternative/complement to autogenous bone for grafting in implant dentistry
- 2008
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Ingår i: Periodontology 2000. - : Wiley. - 0906-6713 .- 1600-0757. ; 47:1, s. 172-92
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Tidskriftsartikel (refereegranskat)abstract
- Autogenous bone, with its osteogenic, osteoinductive and osteoconductive properties, has long been considered the ideal grafting material in bone reconstructive surgery (26, 85). However, drawbacks with autogenous bone include morbidity, availability and unpredictable graft resorption (85, 93, 94, 128, 167, 174). Recent advances in biotechnology have provided the implant surgeon with access to a great variety of bone grafting materials and the possibility of easier implant treatment for the patient as well as for the surgeon. However, the perfect grafting material has yet to be identified. Current research focuses on proteins and carriers for delivering growth factors to the surgical site; however, drawbacks of high production costs and unpredictable results exist. The clinical usefulness of a great variety of materials for bone augmentation in implant dentistry has been seriously questioned (56). The use of osteconductive osteobiologics in implant dentistry remains an experimental procedure until more knowledge becomes available regarding the clinical and biologic aspects of these materials. Osteoinduction denotes a process of accelerated bone formation that provides an abbreviated healing period. Using solely an osteoconductive grafting material may prolong the healing period with 2–6 months, which may be of clinical significance. Uncontrolled case reports, which suggest a graft healing period of 3–4 months for osteoconductive deproteinized bovine bone or biphasic materials, may mislead the inexperienced dentist. Furthermore, clinical recommendations seem premature when based upon a few animal studies rather than upon comprehensive long-term investigations in humans. This review discusses clinical studies of bone substitutes, growth factors and bone graft procedures employed with the purpose of augmenting periimplant sites.
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| 4. |
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| 5. |
- Leiggener, C., et al.
(författare)
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A selective laser sintering guide for transferring a virtual plan to real time surgery in composite mandibular reconstruction with free fibula osseous flaps
- 2009
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Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0901-5027 .- 1399-0020. ; 38:2, s. 187-192
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Tidskriftsartikel (refereegranskat)abstract
- The free fibular flap is the standard procedure for reconstructing mandibular defects. The graft has to be contoured to fit the defect so preoperative planning is required. The systems used previously do not allow transfer of the surgical plan to the operation room in an optimal way. The authors present a method to bring the virtual plan to real time surgery using a rapid prototyping guide. Planning was conducted using the Surgicase CMF software simulating surgery on a workstation. The osteotomies were translated into a rapid prototyping guide, sterilised and applied during surgery on the fibula allowing for the osteotomies and osteosynthesis to be performed with intact circulation. During reconstruction the authors were able to choose the best site for the osteotomies regarding circulation and as a result increased the precision and speed of treatment.
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| 6. |
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| 7. |
- Thor, Andreas, et al.
(författare)
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Bone formation at the maxillary sinus floor following simultaneous elevation of the mucosal lining and implant installation without graft material : an evaluation of 20 patients treated with 44 Astra Tech implants
- 2007
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Ingår i: Journal of oral and maxillofacial surgery (Print). - : Elsevier BV. - 0278-2391 .- 1531-5053. ; 65:7, s. 64-72
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Restoration of lost dentition in the severely artrophic posterior maxilla has for the last 2 decades been successfully treated with various sinus augmentation techniques and installation of dental implants. The use of graft material is anticipated to be necessary; however, recent studies have demonstrated that the mere lifting of the sinus mucosal lining and simultaneous placement of implants result in bone formation. This study was conducted in order to evaluate simultaneous sinus mucosal lining elevation and installation of dental implants without any graft material. PATIENTS AND METHODS: Twenty patients were consecutively included from November 2001 to June 2004. Forty-four Astra ST dental implants (Astra Tech AB, Mölndal, Sweden) with a diameter of 4.5 mm or 5 mm were installed in 27 sinuses. A sinus lift was performed where a cortical window was removed from the maxillary anterior sinus wall. The sinus mucosal lining was elevated and implants installed in the residual subantral bone. The cortical window was thereafter replaced and the incision closed. The remaining bone height was recorded during surgery as well as perforations of the sinus mucosal lining. After 6 months of healing, abutments were connected (the series included 5 1-stage procedures). Clinical and radiological follow-up after loading was performed up to 4 years after implant installation. RESULTS: Patients tolerated the procedure well as few complications were observed. Firm primary stability was achieved for all implants at installation with bone levels in residual bone of 2 to 9 mm. Perforations of the maxillary sinus mucosal lining occurred in 11 of the 27 operated sinuses (41%). One implant was lost during a mean follow-up of 27.5 months (range, 14 to 45 months) giving an implant survival rate of 97.7%. The average gain of bone at the sinus floor was 6.51 mm (SD = 2.49, 44 implants) including all measured implants after a minimum of 1 year follow-up. Marked bone formation was observed around long implants and also when the residual bone below the sinus was diminutive. CONCLUSIONS: The present study including 20 patients showed consistent bone formation at the maxillary sinus floor following simultaneous mucosal lining elevation and installation of implants. It is suggested that the use of this technique can reduce the risk for morbidity related to harvesting of bone grafts and eliminate costs for grafting materials.
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| 8. |
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| 9. |
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| 10. |
- Thor, Andreas, et al.
(författare)
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Early bone formation in human bone grafts treated with platelet-rich plasma: preliminary histomorphometric results
- 2007
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Ingår i: INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY. - Amsterdam : Elsevier BV. - 0901-5027 .- 1399-0020. ; 36:12, s. 1164-1171
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) on early and late bone healing after autogenous maxillary sinus grafting. Eleven patients were subjected to sinus augmentation with particulated autogenous bone bilaterally with the addition of PRP in one side. Platelet counts in baseline whole blood and PRP were registered. Biopsies were taken in the grafted bone of the sinus area with trephine at 3 months (nine patients) and simultaneously a micro-implant was installed in the same region. The micro-implants with surrounding bone were retrieved by biopsy at 6 months (seven patients). Undecalcified cut and ground sections were histomorphometrically analysed. Quantification of new and old bone in all biopsies was performed. The results of this histological study showed that significantly more new bone was formed at PRP-treated sites compared to controls after 3 months of healing. After 6 months, this effect could no longer be observed. This is in accordance with previous studies showing that PRP has a rather low regenerative capacity but may influence the early phase of bone healing. The additional value of PRP in autogenous bone grafts in the maxillary sinus is questionable.
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| 11. |
- Thor, Andreas, et al.
(författare)
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Fracture of the tibia : Complication of bone grafting to the anterior maxilla
- 2006
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Ingår i: British Journal of Oral & Maxillofacial Surgery. - : Elsevier BV. - 0266-4356 .- 1532-1940. ; 44:1, s. 46-48
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Tidskriftsartikel (refereegranskat)abstract
- Autogenous tibial cancellous bone has been used for reconstructive operations in oral and maxillofacial surgery for over 10 years, and has reduced many of the problems associated with conventional sites of autogenous grafts such as the iliac crest. The ease of access for harvesting, the speed of the operation, and the abundance of bone, are advantages of this donor site. We report a patient who had a graft taken from the proximal tibia and had a displaced fracture 2 weeks later after a fall. Five similar cases have been reported previously, of which none has required surgical intervention.
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| 12. |
- Thor, Andreas, et al.
(författare)
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Functional reconstruction of the temporomandibular joint with a free fibular microvascular flap
- 2008
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Informa UK Limited. - 0284-4311 .- 1651-2073. ; 42:5, s. 233-40
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Tidskriftsartikel (refereegranskat)abstract
- By preserving the temporomandibular joint (TMJ) disc in the glenoid fossa at the time of resection, correctly securing the vascularised fibular end in the fossa, and by reattaching the lateral pterygoid muscle, it is possible to maintain normal rotation, translatation, and protrusion in the TMJ and the function of the jaw can be totally restored. We describe four patients in whom good function was achieved in three; this is underlined by extensive remodelling of the condylar head seen at radiological follow-up up to 36 months.
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| 13. |
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| 14. |
- Thor, Andreas, 1962
(författare)
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On platelet-rich plasma in reconstructive dental implant surgery.
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract Background Severe athrophy of the edentulous maxilla may require augmentation before implants can be placed. Autogenous bone has been used for reconstruction in block or in particulated form. Platelet-rich plasma has been suggested to enhance the healing of bone grafts, as activated platelets release autologous growth factors (GFs) into the wound healing site. Additionally, the GFs of PRP are suggested to enhance the integration of implants into bone. However, controversies exist in the literature with respect to the effect of combining PRP with bone grafts, or implants, as the concept has been evaluated in different study models with a wide range of results. Aims The first two Papers presented, evaluates the effects of PRP in conjunction with autogenous bone grafts and subsequent installation of implants. Paper III explores the thrombogenic properties in vitro of titanium in whole blood and PRP and also evaluates the potential effect of a fluoride titanium surface modification regarding the thrombotic response. Furthermore, a recently developed surgical procedure is evaluated in Paper IV, where simultaneous sinus mucosal lining elevation and installation of implants is performed without the addition of any graft material. Finally in Paper V, an attempt to correlate platelet count, GF release in PRP and its effect on bone formation is performed in a canine peri-implant defect model, where additionally, the modified surface from Paper III is further evaluated. Materials & Methods In Paper I, 19 patients were subjected to autogenous bone grafting from the iliac crest to the maxillary sinus with or without PRP in a split mouth setting. Implants were installed (n=152) after 6 months of healing. Patients were followed with Resonance Frequency Analysis (RFA) and radiological follow-up up to 1 year after loading of implants. 3 months after grafting, biopsies were retrieved and micro implants installed in the grafted site, left to heal for 3 months and thereafter collected with surrounding bone, simultaneously with installation of dental implants. Biopsies from 3 and 6 months were evaluated regarding new bone formation and bone-implant contact in Paper II. In Paper III, in vitro tests with the heparinised slide chamber model were performed. In this model, the tested biomaterial is the only part of a secluded chamber that is not furnished with heparin, and therefore the tested surface is allowed to cause thrombotic reactions in e.g. blood or PRP, that subsequently can be quantified regarding e.g. generation of thrombin and platelet activation. Paper IV consisted of 20 patients, followed clinically and with radiology for a minimum of 1 year. These patients were all subjected to elevation of the sinus mucosal lining, where a bone window was cut out in the sinus wall and replaced after installation of implants (n=44) consequently tenting the mucosal lining. 6 dogs were used in Paper V. Peri-implant defects were created in the mandibles and implants with and without a fluoride titanium surface were installed. PRP or whole blood thereafter filled the defects before closing of the surrounding soft tissues and the dogs left to heal for 5 weeks before collection of samples for histomorphometric evaluations. Results Paper I showed an overall survival rate of 98.7 % after 1 year in function and stable marginal conditions regardless use of PRP or not. RFA disclosed significantly higher values for the PRP side at abutment connection after 6 months but not at the 1 year follow up. Early bone healing was enhanced with PRP as evaluated in biopsies collected from grafts after 3 months of healing, however, no differences were found in biopsies with micro implants after 6 months. Whole blood showed a stronger activation of the coagulation system, in Paper III, and a fluoride modification of a titanium surface seemed to augment the effect. In Paper IV, the survival rate of implants was 97.7% after a minimum of 1 year of evaluation and the average bone gain was 6.51 mm. Marked bone formation was observed around implants also when installed in diminutive amounts of bone. In Paper V, the use of PRP added no significant value to the healing of defects. Regardless of PRP or blood in the defects, a fluoride titanium surface modification enhanced the bone healing significantly. Conclusions This thesis supports the use of PRP in augmentation with particulated autogenous bone due to enhanced early healing and enhanced handling abilities. The use of PRP and implants in combination can not be supported as a result of in vitro and experimental animal studies performed in this thesis. Implant surface characteristics seems to be more important. Bone grafts may be obleviated during sinus lift surgery if the described method is used and will result not only in acceptable results of implant integration, but also in minimising morbidity of patients.
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| 15. |
- 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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| 16. |
- Thor, Andreas, et al.
(författare)
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Repair of a laryngeal fracture using miniplates
- 2007
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Ingår i: International Journal of Oral and Maxillofacial Surgery. - : Elsevier BV. - 0901-5027 .- 1399-0020. ; 36:8, s. 748-750
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Tidskriftsartikel (refereegranskat)abstract
- Injuries to the larynx (voice box) can lead to loss of vital functions; the airway may be obstructed, the voice distorted or lost, and the protection of the airway during swallowing may fail. In order to preserve these functions, a stable repair that restores the anatomy as closely as possible is needed. The repair should interfere minimally with the neuromuscular functions of the larynx. The case is described of a 59-year-old male who suffered a severe laryngeal fracture in a work-place accident. Utilizing miniplates, the fracture was reduced and fixed in the correct position. After healing, the patient could be decannulated and has regained his voice, swallows without difficulty and has a patent airway. The results have been sustained over a 2-year follow-up.
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| 17. |
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| 18. |
- Thor, Andreas, et al.
(författare)
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The role of whole blood in thrombin generation in contact with various titanium surfaces
- 2007
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 28:6, s. 966-74
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Tidskriftsartikel (refereegranskat)abstract
- Understanding of the thrombotic response (activation of the intrinsic coagulation system followed by platelet activation) from blood components upon contact with a titanium dental implant is important and not fully understood. The aims of this study were to evaluate: (1) the thrombogenic response of whole blood, platelet-rich plasma (PRP) and platelet-poor plasma (PPP) in contact with a highly thrombogenic surface as titanium, (2) the thrombogenic response of clinically used surfaces as hydroxyapatite (HA), machined titanium (mTi), TiO2 grit-blasted titanium (TiOB) and fluoride ion-modified grit-blasted titanium (TiOB-F). An in vitro slide chamber model, furnished with heparin, was used in which whole blood, PRP or PPP came in contact with slides of the test surfaces. After incubation (60 min rotation at 22 rpm in a 37 degrees C water bath), blood/plasma was mixed with EDTA or citrate, further centrifuged at +4 degrees C (2200 g at 10 min). Finally, plasma was collected pending analysis. Whole blood in contact with Ti alloy resulted in the binding of platelets to the material surface and in the generation of thrombin-antithrombin (TAT) complexes. With whole blood TAT levels increased 1000-fold compared with PRP and PPP, in which both almost no increase of TAT could be detected. In addition, the platelet activation showed a similar pattern with a 15-fold higher release of beta-TG in whole blood. In the in vitro chamber model with the clinically relevant materials, the fluoride-modified surface (TiOB-F) showed pronounced TAT generation compared with TiOB, mTi and HA. Similar results were achieved for platelet consumption and activation markers of the intrinsic coagulation system. Taken together these results implicate first that whole blood is necessary for sufficient thrombin generation and platelet activation during placement of implants. Second, a fluoride ion modification seems to augment the thrombogenic properties of titanium.
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| 19. |
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| 20. |
- Toljanic, Joseph A., et al.
(författare)
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Implant Rehabilitation of the Atrophic Edentulous Maxilla Including Immediate Fixed Provisional Restoration Without the Use of Bone Grafting : A Review of 1-Year Outcome Data from a Long-Term Prospective Clinical Trial
- 2009
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Ingår i: International Journal of Oral & Maxillofacial Implants. - 0882-2786 .- 1942-4434. ; 24:3, s. 518-526
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The literature suggests that predictable integration can be achieved when dental implant placement is combined with immediate fixed provisional restoration in a variety of clinical situations. Fewer data are available, however, regarding outcomes for immediate provisional restoration of implants in the edentulous maxilla. This report presents 1-year data acquired from a long-term prospective clinical trial designed to assess outcomes following the immediate provisional fixed restoration of implants in the atrophic edentulous maxilla without the use of bone augmentation. Materials and Methods: Fifty-one subjects diagnosed with an atrophic edentulous maxilla received a total of 306 implants (six implants per subject) followed by fixed provisional restoration within 24 hours of implant placement. No subjects underwent grafting to enhance bone volume in preparation for implant treatment. Data acquired included bone quantity and quality, implant dimensions, implant locations, and implant placement stability. Subjects returned for 1-year follow-up examinations to assess implant integration and restoration function. Periapical radiographs were obtained and compared to baseline images to assess marginal bone height maintenance. Results: At the 3-month follow-up examination, 294 of 306 implants placed in 51 subjects were found to be integrated. This represents a cumulative implant survival rate of 96%. At the 1-year follow-up examination, mean marginal bone loss of 0.5 mm was noted, with no further loss of implants. Conclusions: These results support the contention that predictable long-term outcomes may be obtained for the atrophic edentulous maxilla when treated with an implant rehabilitation protocol that includes immediate fixed provisional restoration without the use of bone grafting. This strategy offers a promising treatment alternative for the patient with an atrophic edentulous maxilla.
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| 21. |
- Zätterström, Ulf, et al.
(författare)
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Cervical metastasis from Spitz nevus of the buccal mucosa
- 2008
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Ingår i: Melanoma research. - 0960-8931 .- 1473-5636. ; 18:1, s. 36-39
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Tidskriftsartikel (refereegranskat)abstract
- A 23-year-old woman was presented with a prolonged history of a small lump in the buccal mucosa. A local excision was performed. The morphology diagnosed a Spitz nevus and she underwent supplementary excision of scar tissue. Two years later a submandibular lump appeared on the ipsilateral side of the neck. Cytology from fine needle aspiration indicated spread of a melanocytic tumor and she underwent a modified supraomohyiod neck dissection. One of the lymph nodes showed an inclusion of cells in the deep layers with epitheloid and spindle cells in a pattern similar to that of the primary oral lesion. The finding suggests a mechanical spread of melanocytes from the Spitz nevus to the regional lymph node. After more than 3 years of follow-up there is no further manifestation of disease. It is believed that this may be an example of how a Spitz tumor, although inherently benign, can spread along lymphatics in a pseudometastatic fashion. To our knowledge this is the first report of an oral Spitz melanoma with metastatic behavior.
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