Comparison of bicortical, miniplate and hybrid fixation techniques in mandibular advancement and counterclockwise rotation: A finite element analysis study.

OBJECTIVE: This study aims to evaluate biomechanical stability and stress distribution of five different fixation types with finite element analysis using 10-mm advancement with or without counterclockwise rotation of the mandible. MATERIALS AND METHODS: After sagittal split osteotomy, 10-mm advancement was performed in the first group and 10-mm advancement and 10-degree counterclockwise rotation were performed in the second group. One miniplate (M-1), two-miniplate (M-2), one miniplate and a bicortical screw (H), l-shaped bicortical screw (B-1), and inverted l-shaped bicortical screw (B-2) systems were placed. Totally, 120 N force was applied to the models at a 45-degree angle from the lower edge of the symphysis. RESULTS: The highest values on fixation were seen with miniplate, while the mean values were obtained with bicortical screw system. The highest values on bone were achieved using bicortical screws. One miniplate (M-1) showed both the highest and mean displacement. The highest values in counterclockwise-rotated models increased in all parameters, compared to non-rotated models. CONCLUSION: In cases in which passive alignment between segments and adequate bone contact are ensured, inverted l-shaped bicortical screw, two-miniplate, or hybrid systems are recommended.

Retromandibular transparotid approach for subcondylar mandibular fractures: A retrospective study.

BACKGROUND: The aim was to evaluate the effectiveness and complications of retromandibular transparotid approach performed for the reduction of dislocated subcondylar fractures. METHODS: Fourteen patients with subcondylar mandibular fractures were evaluated (8 male, 6 female, age range 19-43 years). The primary predictor variable in the present study was time (preoperative vs postoperative). The primary outcome variables were inflammatory complication, facial nerve deficit (House and Brackmann classification), and presence of parotid fistula. The secondary outcome variables were occlusal disturbances, maximal interincisal opening (MIO), and temporomandibular joint (TMJ) pain (VAS). RESULTS: Excellent occlusion and function was observed postoperatively. One salivary fistula occurred after surgery but was healed after 3 weeks. No inflammatory complication was observed. Three patients had grade III and one patient had grade II facial nerve deficit, all recovered in 6 weeks. All patients were free of pain and no malocclusion was observed. MIO was ranging from 34 to 58 mm (mean 44.4 mm) after 6 months. CONCLUSION: The retromandibular transparotid approach is feasible and safe. It facilitates reduction and fixation of subcondylar fractures with functional outcomes and rare complications.

Implant Rehabilitation for Extremely Atrophic Maxillae (Cawood Type VI) with Le Fort I Downgrafting and Autogenous Iliac Block Grafts: A 4-year Follow-up Study.

PURPOSE: The aim of this 4-year retrospective follow-up study was to investigate treatment outcomes, including implant survival rate and marginal bone loss, in patients with maxillary Cawood type VI atrophy pattern who underwent Le Fort I downgrafting and iliac block augmentations for implant rehabilitation. MATERIALS AND METHODS: Retrognathic edentulous Class III patients with severe maxillary resorption (Cawood VI) were enrolled. Reconstructive procedures performed included Le Fort I maxillary osteotomy, iliac block grafting, labial sulcoplasties, and dental implant placement. Panoramic radiographs were used to assess marginal bone loss. The Nobel Biocare Replace and GMI Frontier dental implant systems and fixed partial dentures were used for dental rehabilitation. Statistical analyses were made using NCSS 2007 statistical software, with significance set at P < .05. RESULTS: Ten patients (six men and four women) with a mean age of 50.4 ± 12.55 years underwent maxillary osteotomy (advancement: 9 ± 1.4 mm; inferior repositioning: 8 ± 1.0 mm) and iliac block sandwich grafting (posterior ilium: n = 3; anterior ilium: n = 7) from 2009 to 2015. Nine patients were treated with a two-stage protocol. The mean graft healing period was 5.9 ± 0.73 months. A total of 98 implants were placed, 80 in maxillae and 18 in mandibles. The Nobel Biocare Replace system was used in two patients (n = 29 implants) and GMI Frontier system was used in eight patients (n = 69 implants). Implant numbers in the maxilla were: 6 implants in 2 patients, 8 implants in 6 patients, and 10 implants in 2 patients. The mean follow-up period was 47.8 ± 3.4 months. The success rate was 93.75%, with a 6.25% fail ratio (n = 9 implants) at a follow-up of 4 years. Marginal bone resorption was 1.8 ± 1.0 mm at the postoperative year 1 and 3.75 ± 0.85 mm at postoperative year 4. Marginal resorption in the 8-implant group was found to be higher than that in the 6-implant group and 10-implant group at the postoperative year 1 (P = .045, P = .026, P < .05, respectively). CONCLUSION: Le Fort I osteotomy and simultaneous iliac block grafting (downgrafting) is a valuable option for implant rehabilitation in extremely atrophic maxillae (Cawood VI). It showed a high survival rate (93.75%) at 4 years of follow-up in this study.

Bone healing after biodegradable mini-plate fixation.

PURPOSE: To compare bone healing in mandibular vertical body osteotomies (MVBO) after fixation with a resorbable 2.0mm-profile fixation system in the first and third postoperative months in rabbits. METHODS: Twenty hemimandibles of ten rabbits were divided into two groups according to duration of resorbable fixation-one or three months. The MVBOs were performed and one four-hole, resorbable, 2.0mm mini-plate fixation system was used on each side. The computed tomography (CT) scans, scanning electron microscopy (SEM), and histomorphometric outcomes of groups I and II were compared. RESULTS: Significant differences were found between the one- and three- month assessments in terms of newly formed bone ratio values (p<0.05). There was more new bone formation at the third month on both the CT and histomorphometric examinations. A better adaptation of the bone tissues to the resorbable mini-plate and screws was observed on SEM at three months. CONCLUSION: The resorbable mini-plates provided a fixation stable enough to allow immediate oral alimentation and callus formation in both groups.

Bone healing after biodegradable mini-plate fixation

ABSTRACT PURPOSE: To compare bone healing in mandibular vertical body osteotomies (MVBO) after fixation with a resorbable 2.0mm-profile fixation system in the first and third postoperative months in rabbits. METHODS: Twenty hemimandibles of ten rabbits were divided into two groups according to duration of resorbable fixation-one or three months. The MVBOs were performed and one four-hole, resorbable, 2.0mm mini-plate fixation system was used on each side. The computed tomography (CT) scans, scanning electron microscopy (SEM), and histomorphometric outcomes of groups I and II were compared. RESULTS: Significant differences were found between the one- and three- month assessments in terms of newly formed bone ratio values (p<0.05). There was more new bone formation at the third month on both the CT and histomorphometric examinations. A better adaptation of the bone tissues to the resorbable mini-plate and screws was observed on SEM at three months. CONCLUSION: The resorbable mini-plates provided a fixation stable enough to allow immediate oral alimentation and callus formation in both groups.

Does ultrasonic resorbable pin fixation offer predictable results for augmentation eminoplasty in recurrent dislocations?

PURPOSE: To assess the outcome of interpositional calvarial block grafting fixed with an ultrasonic resorbable system (SonicWeld, KLS Martin, Mühlheim, Germany) for augmentation eminoplasty in chronic recurrent condylar dislocations. PATIENTS AND METHODS: We designed and implemented a retrospective cohort study. Eight female patients (mean age 48 years) were treated. The primary predictor variable was time (preoperative vs postoperative). The primary outcome variable was cessation of dislocation. The secondary outcome variables were the height of the articular eminences (HAE), maximum interincisal opening, pain score (visual analog scale [VAS]), postoperative magnetic resonance imaging (MRI) findings, and facial nerve paralysis. RESULTS: All 8 patients had been experiencing recurrent dislocations a mean of 10 times each month preoperatively. None of the patients had experienced a dislocation at 2 years postoperatively. The preoperative mean HAE was 5.75 and the VAS score for pain was 72.5. The mean vertical HAE was 15.75 mm, and the mean VAS score for pain was 11.2 at 12 months postoperatively. Complete resorption of the SonicWeld pins was observed on the first year follow-up computed tomography scans. Of the 8 patients, 3 presented with disc displacement without reduction and 2 with disc displacement with reduction on the postoperative MRI scan, and none of the patients had a facial nerve deficit at 24 months of follow-up. CONCLUSIONS: Fixation of cortical calvarial grafts using the ultrasonic resorbable system for augmentation eminoplasty provided sufficient stabilization and favorable outcomes. Degradation of the osteosynthesis material and the absence of intermaxillary fixation were the most advantageous parts of the technique.

Evaluation of temporomandibular joint disc-repositioning surgery with Mitek mini anchors.

PURPOSE: The aim of this study is to evaluate outcome of Mitek mini anchors (DePuy Mitek, Raynham, MA) in TMJ discopexy and assess patient satisfaction based on MRI findings. PATIENTS AND METHODS: 7 patients suffered from significant pain and dysfunction diagnosed on MRI findings as anterior disc displacement without reduction selected for this study. Anchor stability, assessment of positional changes and roofing were evaluated by postop MRI and OPTGs. Satisfaction was assessed with VAS. Preop and postop maximum interincisal opening measurements were compared. RESULTS: There was significant difference between preop and posto P values of MIO and VAS. All 7 patients noted complete absence of pain at the postop 1-year follow-up. Only 1 patient had postop clicking but showed remarkable improvement of jaw functions (MIO). The articular disk was observed at its normal position in 6 patients except one patient whom MRI confirmed postop partial roofing. OPTGs reveal neither radiologic changes around the mini anchors in the condylar head nor any positional shifts. CONCLUSION: Disc repositioning with Mitek mini anchors represent improvement in post-op VAS scores and clinical findings (MIO) based on comparison preop and postop MRI scans and panoramic films. However, our study group consists of limited number of patients, further studies with more number of cases are required to evaluate the outcomes.

Rigid external maxillary distraction and rhinoplasty for pyknodysostosis.

AIM: This article reports the treatment of an 33-year-old female patient with pyknodysostosis by rigid external distraction II midface distraction system. STUDY DESIGN: The patient with pyknodysostosis described in this report had severe midfacial hypoplasia. Correction of this by use of routine orthognathic surgery would require osteosynthesis and bone grafting. Risk of infection and/or nonunion after such a surgical procedure was considered too great, and therefore the possibility of treatment by distraction osteogenesis of the maxilla was evaluated. The rigid external distraction II midface distraction system was used to relocate the hypoplastic maxilla at anterior-inferior projection. CONCLUSIONS: Distraction osteogenesis should be considered as the primary reconstructive method for maxillofacial deformities in patients with sclerosing bone dysplasias, since this is the second reported case treated successfully with rigid external distraction.

The role of controlled hypotension upon transfusion requirement during maxillary downfracture in double-jaw surgery.

INTRODUCTION: To evaluate the role of induced hypotension during maxillary downfracture osteotomy on the requirement for blood transfusion, duration of operation and induced anaemia in bimaxillary surgery. MATERIAL AND METHODS: 45 young orthognathic patients were operated under hypotensive anaesthesia between 2004 and 2006. Operations were LeFort I osteotomies (n=45), bilateral sagittal split osteotomies (BSSO) (n=42), segmental osteotomies (n=3), tongue reduction (n=1), genioplasties (n=15), digastric myotomies (n=2), and bone grafts were the supplementary procedures. Pre-postoperative haemograms, intraoperative blood loss, and duration of operations were the studied parameters. Statistical analysis was performed using SPSS 11.5 for Windows. RESULTS: None of the patients received a blood transfusion. Mean blood loss was 377+/-111.2mL with the range of 180mL to the maximum of 625mL. Mean duration was 267.1+/-61.2min with minimum of 180min and maximum of 400min. Mean preop Hb level was 14+/-1.9g/dL with the range from 10.3g/dL to a maximum of 17.2g/dL. Mean postop Hb level was 11.8+/-2g/dL with a range of 8.2-16.2g/dL levels. Preop erythrocyte counts were 435.3+/-18.2 and 416.4+/-16.1 (x104/mcL) on the first postop day. CONCLUSION: Transfusion in bimaxillary orthognathic surgery could be prevented by induction of hypotension during maxillary downfracture.

The role of computer-aided 3D surgery and stereolithographic modelling for vector orientation in premaxillary and trans-sinusoidal maxillary distraction osteogenesis.

BACKGROUND: Maxillary distraction osteogenesis is a challenging procedure when it is performed with internal submerged distractors due to obligation of setting accurate distraction vectors. METHODS: Five patients with severe maxillary retrognathy were planned with Mimics 10.01 CMF and Simplant 10.01 software. Distraction vectors and rods of distractors were arranged in 3D environment and on STL models. All patients were operated under general anaesthesia and complete Le Fort I downfracture was performed. RESULTS: All distractions were performed according to orientated vectors. All patients achieved stable occlusion and satisfactory aesthetic outcome at the end of the treatment period. CONCLUSION: Preoperative bending of internal maxillary distractors prevents significant loss of operation time. 3D computer-aided surgical simulation and model surgery provide accurate orientation of distraction vectors for premaxillary and internal trans-sinusoidal maxillary distraction. Combination of virtual surgical simulation and stereolithographic models surgery can be validated as an effective method of preoperative planning for complicated maxillofacial surgery cases.

Assessment of synovial vascularization by power Doppler ultrasonography in TMJ internal derangements treated arthroscopically.

Our aim was to evaluate the effect of arthroscopic lysis and lavage of the temporomandibular joint (TMJ) on synovial microvascularisation by comparing preoperative and postoperative grades measured by power Doppler ultrasonography (US). We studied 22 patients with hypomobility, clicking, and pain in the TMJ. Power Doppler US were obtained preoperatively to assess the presence of synovial microvascularisation, and arthroscopic lysis and lavage were done after conservative treatment had proved unsuccessful. The severity of synovitis was assessed arthroscopically. The postoperative power Doppler US scans were obtained 2 months later. Other arthroscopic variables were roofing, adhesions, chondromalacia, clicking, and pain. Arthroscopic synovitis with varying degrees of synovial vascularisation was detected in all patients. Pain scores decreased considerably during the postoperative period. We conclude that power Doppler US is a good technique for the assessment of synovial changes by microvascularisation. Arthroscopy of the TMJ reduces synovial vascularisation.

Posterior maxillary segmental osteotomy for restoring the mandible with dental implants: a clinical report.

Posterior segmental collapse causes narrowing of interarch space and prevents adequate restoration in the posterior quadrant. Posterior maxillary segmental osteotomy (PMSO) is an alternative option that enables prosthodontic restoration with an implant-supported fixed partial denture. The following clinical report describes prosthodontic rehabilitation with fixed prostheses after a posterior maxillary segmental osteotomy for a patient with a partially edentulous mandible.

Resonance frequency analysis assessment of implant stability in labial onlay grafted posterior mandibles: a pilot clinical study.

PURPOSE: The objectives of this study were (1) to compare the stability, evaluated by means of resonance frequency analysis (RFA), of implants placed posterior mandibles augmented with autogenous bone harvested from the mandibular symphysis with that of implants placed in nongrafted edentulous posterior mandibles and (2) to compare peri-implant marginal bone height changes and implant failure for the 2 groups. MATERIALS AND METHODS: Eight patients with thin posterior mandibular ridges (buccolingual crestal width less than 4 mm) underwent labial onlay alveolar grafting with symphyseal bone blocks 4 months prior to placement of 17 implants. Seven nongrafted patients received 18 implants in the edentulous posterior mandible; these patients served as a control group. RFA was performed the day of implant placement (baseline), 1 month postplacement, 4 months postplacement (after prosthesis delivery), and 12 months postloading. Peri-implant bone height changes at a level of 0.01 mm were assessed using periapical radiographs at baseline, the 1-month follow-up, and the 4-month follow-up. Analysis of variance was used to evaluate statistical differences within the groups, and t test was used to make comparisons between groups. RESULTS: None of the patients presented postoperative complications or implant failure. Mean implant stability quotient (ISQ) was 63.0+/-6.0 to 70.2 +/-3.5 for the grafted group and 64.1+/-4.1 ISQ to 70.1+/-3.9 for the nongrafted group. No significant difference was found in mean ISQ between the grafted and nongrafted groups at baseline, the 1-month follow-up, 4 months postplacement, or 12 months postloading (P = .211, P = .873, P = .925, P = .735, respectively). Mean peri-implant bone loss was 0.16 +/- 0.04 mm mesially and 0.16 +/- 0.05 mm distally. CONCLUSION: RFA revealed no difference in implant stability between mandibular ridges augmented with autologous bone grafts at baseline or after loading.

Evaluation of osseous regeneration in alveolar distraction osteogenesis with histological and radiological aspects.

PURPOSE: Alveolar distraction osteogenesis is used for reconstruction of defects caused by trauma, periodontal disease, or congenital anomalies of the dentoalveolar region. PATIENTS AND METHODS: Alveolar distraction osteogenesis was performed on 10 patients with various vertical alveolar defects in the mandible. Panoramic radiographs and computed tomography (CT) scans were obtained preoperatively. At the end of 12 weeks, panoramic radiographs and dental CT scans were taken and the bony specimens were harvested from the distracted areas by trephine bur for histologic evaluation. After a year, the status of the distraction areas was assessed by radiographs and dental CT scans. Densities of the newly formed bone were evaluated at the twelfth week and the first year by dental CT scans. RESULTS: At the twelfth week, tubular bone was longitudinally oriented and osteoblastic activation was increased; the osseous density in the distraction chamber was higher than the original medullary bone density, which increased from the twelfth week to the first year. The regenerated bones were more dense (866.81) than the pre-existing medullary bone (309.66), and less dense than the pre-existing cortical bone (1641.12) at the twelfth week. Bone densities were seen to have increased gradually by the end of the first year (1089.99). CONCLUSION: Alveolar distraction osteogenesis can be used successfully for reconstruction of alveolar bone deficiencies caused by trauma or periodontal defects.

Endoscopic retrieval of dental implants from the maxillary sinus.

Endoscopic sinus surgery has been performed for various indications in maxillofacial surgical practices. It has been utilized for assessment of antral pathologies, removal of foreign bodies, orthognathic procedures, and treatment of facial fractures. In the cases presented, 3 dental implants which were displaced into maxillary sinuses were removed by endoscopic sinus surgery. Transantral endoscopic surgery is a reliable, minimally invasive method for retrieving displaced objects from the maxillary antrum with minimal complications.

Prosthodontic rehabilitation after traumatic tooth and bone loss: a clinical report.

Traumatic injuries from motor vehicle accidents may cause anatomic deficiencies in soft and hard tissues. Successful treatment of patients with such deficiencies may include preprosthetic surgery using osseointegrated implants to increase prosthesis retention and stability. This article describes the treatment of a motor vehicle accident victim whose anterior teeth and supporting tissues were lost.

Immediately loaded anterior single-tooth implants: two cases.

Immediate loading of implants into fresh extraction sockets has the advantage of decreasing the period of healing, reducing the resorption of the alveolar bone, and achieving optimal esthetic results. These cases reveal the clinical success of immediate loaded single-tooth implants placed in fresh extraction sites.

Alternative bone expansion technique for immediate placement of implants in the edentulous posterior mandibular ridge: a clinical report.

PURPOSE: The aim of this study was to evaluate the effectiveness of a split-crest bone augmentation technique performed for immediate implant placement in thin edentulous posterior mandibular ridges. MATERIALS AND METHODS: In the present study, 125 implants were placed in posterior mandibular ridges of 30 patients. The mandibular buccal walls were split, expanded, and grafted with a combination of platelet-rich plasma and Cerasorb. The split segments were held in place by cortical bone screws. Before loading, periodontal status was checked, implant stability was evaluated with the Periotest, and panoramic radiographs and computerized tomography scans were obtained. Second-stage surgery (cover screw removal and healing abutment placement) was performed after 3 to 4 months. RESULTS: All implants osseointegrated successfully and underwent loading after 4 months. Optimal healing occurred 3 to 4 months earlier than the usual 6 to 9 months required, and no lip paresthesia was noted. DISCUSSION: Although onlay-inlay grafts, sandwich osteotomies, guided bone regeneration, piezoelectricity, and alveolar distraction have been indicated for augmentation in the posterior mandibular region, each of these techniques involves risks and complications. The crest-splitting bone expansion technique enables single-stage immediate implant placement and lateral ridge augmentation in thin crests and may prevent neurosensorial deficiencies. CONCLUSIONS: The split-crest surgical technique is a valid reconstructive procedure for sharp posterior mandibular ridges. If performed using platelet-rich plasma and Cerasorb, it can shorten the osseointegration period.