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Made available in DSpace on 2020-12-12T01:19:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-01 Mandibular reconstruction techniques are always a challenge to oral and maxillofacial (OMF) surgeons. Techniques and treatment plans that offer the patient OMF rehabilitation should always be available. Technological innovations have enabled more rapid, safer, and more secure treatment than in the past. This article describes a case using a different approach. The patient was treated with marginal mandibulectomy and immediate rehabilitation with osseointegrated implants; a hybrid prosthesis was fabricated a short time thereafter. This treatment plan demonstrated its utility and efficiency in this case. An approach with fewer surgeries and OMF rehabilitation needs be considered in all cases. Universidade do Sagrado Coração Instituto Americano de Pesquisa Odontológica ILAPEO College Tufts University School of Dental Medicine Tufts Medical Center Universidade Estadual Paulista UNESP Universidade Estadual Paulista UNESP

This retrospective study evaluated the use of a single miniplate for the treatment of mandibular angle fractures (MAF).Fifty patients with 53 MAF were treated by open reduction and internal fixation with the use of a single miniplate and were analyzed in this study.Five patients with MAF had postoperative complications that required additional procedures. Three patients had postoperative infection, one patient complained of malocclusion in the first postoperative week, and one patient had miniplate exposure three months after surgery. Every additional procedure was performed in the office under local anesthesia without disruption of the initial fracture treatment. Postoperative maxillomandibular fixation (MMF) was performed in four patients. Treatment of MAF using a single miniplate was effective, with low morbidity and with low rates of postoperative complications. MAF can be treated without MMF, and stability is improved when long miniplates are used.The use of a single miniplate is therefore encouraged. However, postoperative MMF should be considered with the presence of little contact between bone segments, malocclusion, or extensive tooth loss.

It is important to understand the factors that can increase the incidence of complications after mandibular fracture (MF) treatment. The objective of the present study was to investigate whether occlusal stability influences the occurrence of postoperative complications in MFs treated with internal rigid fixation.We performed a prospective cohort study of patients treated for MF by osteosynthesis with plate and screw fixation. The primary predictor variable was the occlusal stability (yes vs no). Occlusion was scored as stable (group 1) if the patients had all their teeth and no free ends in either dental arch. Occlusion was coded as unstable (group 2) if the patients were partially edentulous with free ends in either dental arch or had edentulism involving more than 6 dental elements. The primary outcome variable was postoperative complication (yes vs no). The secondary outcome variables were the osteosynthesis system used (2.0 or 2.4 mm), local factors, age, and gender. Statistical analysis was performed using the χOf 115 patients with 121 MFs, 73 (63.48%) had stable occlusion (group 1) and 42 (36.52%) had unstable occlusion (group 2). The mean age was 34.11 years, and 71.3% were men. The postoperative complication rate was 8.70% (10 patients). Of the 10 patients with complications, 3 (2.6%) were in group 1 and 7 (6.1%) were in group 2 (P = .021 and P .05, respectively). The 2.0-mm system was used in 107 cases (93%). All the complications were associated with use of the 2.0-mm osteosynthesis plates, occurring in 3 of 69 patients in group 1 (4.34%) and 7 of 38 patients in group 2 (18.42%; P = .032 and P .05, respectively). The greatest number of complications was associated with unilateral MF (9 of 109). The occurrence of postoperative complications in angle and symphysis/parasymphysis fracture sites was equal.The results of the present study suggest that unstable occlusion could increase the rate of postoperative complications in MFs treated with plates and screws. Future studies are required with occlusal stability included as a variable.

Dental arches areas with teeth presenting dentoalveolar ankylosis and replacement root resorption can be considered as presenting normal bone, in full physiological remodeling process; and osseointegrated implants can be successfully placed. Bone remodeling will promote osseointegration, regardless of presenting ankylosis and/or replacement root resorption. After 1 to 10 years, all dental tissues will have been replaced by bone. The site, angulation and ideal positioning in the space to place the implant should be dictated exclusively by the clinical convenience, associated with previous planning. One of the advantages of decoronation followed by dental implants placement in ankylosed teeth with replacement resorption is the maintenance of bone volume in the region, both vertical and horizontal. If possible, the buccal part of the root, even if thin, should be preserved in the preparation of the cavity for the implant, as this will maintain gingival tissues looking fully normal for long periods. In the selection of cases for decoronation, the absence of microbial contamination in the region - represented by chronic periapical lesions, presence of fistula, old unconsolidated root fractures and active advanced periodontal disease - is important. Such situations are contraindications to decoronation. However, the occurrence of dentoalveolar ankylosis and replacement resorption without contamination should neither change the planning for implant installation, nor the criteria for choosing the type and brand of dental implant to be used. Failure to decoronate and use dental implants has never been reported. RESUMO Áreas dos maxilares com dentes em anquilose alveolodentária e reabsorção dentária por substituição podem ser consideradas como portadoras de osso normal, em pleno processo fisiológico contínuo de remodelação; e os implantes osseointegráveis podem ser aplicados com sucesso. A remodelação óssea promoverá sua osseointegração, independentemente de haver raízes em anquilose e/ou em reabsorção por substituição. Após 1 a 10 anos, todos os tecidos dentários terão sido substituídos por osso. O local, a angulação e o posicionamento ideal no espaço para se colocar o implante devem ser ditados pela conveniência clínica associada, exclusivamente, ao planejamento prévio. Uma das vantagens da decoronação com colocação imediata de implantes em dentes anquilosados e com reabsorção por substituição é a manutenção do volume ósseo na região, tanto vertical quanto horizontalmente. Se possível, deve-se preservar, na preparação da cavidade para o implante, a parte vestibular da raiz, mesmo que fina; isso deixará os tecidos gengivais com aspecto de plena normalidade por longos períodos. O importante na seleção de casos para a decoronação é a ausência de contaminação microbiana na região, representada por lesões periapicais crônicas, presença de fístula, fraturas radiculares antigas não consolidadas e doença periodontal avançada ativa. Essas situações são contraindicações para a decoronação. A ocorrência de anquilose alveolodentária e reabsorção por substituição sem contaminação não deve mudar o planejamento para instalação de implantes, nem mesmo os critérios de escolha do tipo e marca de implante dentário a ser utilizado. Nunca foi relatado fracasso na decoronação e uso de implantes dentários.

This study verified the resistance to displacement of six miniplate fixation methods after sagittal split osteotomy (SSO). SSO was performed in 30 polyurethane synthetic mandible replicas. The distal segments were advanced (4 mm) and specimens were grouped according to the fixation method: four-hole standard miniplate; four-hole locking miniplate; six-hole standard miniplate; six-hole locking miniplate; six-hole standard sagittal miniplate; six-hole locking sagittal miniplate. Biomechanical evaluation was performed by applying compression loads to three points on the second molar region, using an Instron universal testing machine until a 3mm displacement of the segments occurred. Compression loads able to produce 3mm displacement were recorded in kN and subjected to analysis of variance (P0.01) and Tukey's tests for comparison between groups (P0.05). The locking sagittal miniplate showed higher resistance to displacement than the regular four- and six-hole locking and standard miniplates. No significant differences were observed between the locking sagittal miniplate and the regular sagittal or the four-hole locking miniplates. Two of the three groups with the best results had locking plate fixation methods. Fixation of SSO with a single miniplate is better accomplished using six-hole locking sagittal miniplates, six-hole standard sagittal miniplates, or four-hole locking miniplates; these methods are more resistant to displacement.

This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy's osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0 mm miniplates and 2.0 mm × 6 mm monocortical screws. In groups 1 and 2, two conventional (G1) or locking (G2) screws were installed in each bone segment using a conventional (G1) or a locking (G2) straight miniplate; in groups 3 and 4, three conventional (G3) or locking (G4) screws were installed in the proximal segment and four conventional (G3) or locking (G4) screws were installed in the distal segment using a conventional (G3) or a locking (G4) seven-hole straight miniplate. The hemimandibles were loaded in compressive strength until a 4mm displacement occurred between the segments, vertically or horizontally. Locking plate/screw systems provided significantly greater resistance to displacement than conventional ones (p

The implant-supported rehabilitation of atrophic mandibles (AM) with severe bone resorption is challenging for both surgical and prosthetic procedures due to the high risk of mandible fracture during implant surgery and postoperatively due to the masticatory load. The aim of case presentations was to demonstrate treatment alternatives for patients with AM who required oral rehabilitation with osseointegrated implants (OIs) according to the residual mandibular bone volume. When bone is 9 mm in height, the ideal treatment is the use of narrow, short OIs. When the bone height is 5 to < 9 mm, mandibular reinforcement with reconstruction plates using the intraoral approach and simultaneous placement of osseointegrated implants are proposed. In cases where bone height is < 5 mm, the choice of treatment is mandibular reconstructive surgery with an autogenous bone graft and biomaterials. The fundamental principles of this protocol are to reduce the morbidity and complications associated with the surgical procedure, which would reduce both the time and cost of full dental rehabilitation. The choice of the technique for mandibular reconstruction should be indicated according to the magnitude of the atrophy.

The purpose of this paper was to analyze specimens of autogenous bone block grafts exposed to the oral cavity after ridge reconstructions. Specimens of chronic suppurative osteomyelitis (CSO) of the jaws were used as comparison for bacterial colonization pattern. For this, 5 specimens of infected autogenous bone grafts were used and 10 specimens of CSO embedded in paraffin were stained with Brown and Brenn technique and analyzed under light microscopy. The results showed a similar colonization pattern in both situations, with the establishment of bacterial biofilm and the predominance of Gram-positive bacteria. The conclusion was that the similarity in bacterial distribution and colonization between autogenous bone grafts and CSO stresses the necessity of more invasive procedures for the treatment of the autogenous bone grafts early exposed to the oral cavity.

The objective of this study is to discuss problems associated with dental retention through three clinical cases of mandible fractures related to the presence of retained lower third molars, emphasizing the possibility of mandible fractures resulting from this or from the extraction procedure. The three evaluated patients had a fracture in the mandible angle. The third molars were present in all the cases, as was the relationship of the fracture with the teeth. After evaluating the three cases and reviewing literature, it is believed that the presence of the retained lower third molars and the surgical procedures for their extraction increase the risk of mandible angle fractures.

The aim of this in vitro study was to assess the biomechanical stability of 9 different osteosynthesis methods after sagittal split ramus osteotomy by simulating the masticatory forces and using a 3-point biomechanical test method.Forty-five polyurethane hemimandibles with bone-like consistency were randomly assigned to 9 groups (n = 5) and subjected to sagittal split ramus osteotomy. After 4-mm advancement of the distal segment, the bone segments were fixed by different osteosynthesis methods using 2.0-mm miniplate/screw systems: group A, one 4-hole conventional straight miniplate; group B, one 4-hole locking straight miniplate; group C, one 4-hole conventional miniplate and one bicortical screw; group D, one 4-hole locking miniplate and 1 bicortical screw; group E, one 6-hole conventional straight miniplate; group F, one 6-hole locking straight miniplate; group G: two 4-hole conventional straight miniplates; group H, two 4-hole locking straight miniplates; and group I, 3 bicortical screws in an inverted-L pattern. All models were mounted on a base especially constructed for this purpose. Using a 3-point biomechanical test model, the hemimandibles were loaded in compressive strength in an Instron machine (Norwood, MA) until a 3-mm displacement occurred between segments vertically or horizontally. Data were analyzed by analysis of variance and Tukey test (alpha = 1%).The multiparametric comparison of the groups showed a statistically significant difference (P.01) between groups that used 2 miniplates (groups G and H), 1 miniplate and 1 bicortical screw (groups C and D), and only bicortical screws (group I) compared with groups that used only 1 miniplate with 2 screws per segment (groups A and B) and 3 screws per segment (groups E and F).The placement of 2.0-mm-diameter bicortical screws in the retromolar region, associated or not with conventional and locking miniplates with monocortical screws, promoted a better stabilization of bone segments. Locking miniplates presented a better performance in bone fixation in all groups.

The atrophic maxilla often results in lateral, anteroposterior and vertical disproportion of the maxillary arches. This paper presents the case of a 40-year-old male with a severely atrophic maxilla who underwent oral rehabilitation. He was treated with onlay and inlay iliac bone grafts followed by vestibuloplasty and dental implant placement 170 days after initial bone grafting. The dental implants were uncovered after 4 months of healing. The patient also underwent orthognathic surgery for correction of the maxillary basal bone and to improve implant positioning. At the 48-month follow-up there were no complications.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) A ostectomia é uma manobra cirúrgica fundamental que pode afetar a reparação tecidual de modo a aumentar a morbidade do procedimento. O tipo de equipamento e/ou instrumental utilizado para a ostectomia pode influenciar diretamente no reparo ósseo. O objetivo deste trabalho foi analisar o processo de reparação óssea em defeitos realizados em mandíbula de coelho com três diferentes equipamentos. Quinze coelhos foram aleatoriamente divididos em 3 grupos (n=5) de acordo com o equipamento usado para preparacão de 3 cavidades ósseas com brocas padronizadas: I) motor de baixa rotação pneumático, II) motor de alta rotação pneumático e III) motor de baixa rotação elétrico, todos com refrigeração constante. Após os períodos experimentais de 2, 7e 30 dias, as peças anatômicas foram removidas e submetidas a análises microscópica e histomorfométrica. Não houve diferença estatisticamente significante (p>0,05) entre os grupos nos 3 períodos experimentais, considerando-se a área total de matriz óssea mineralizada, embora a análise microscópica tenha revelado uma tendência a um processo de reparação óssea um pouco mais adiantado no grupo III, quando comparado aos demais grupos. Os resultados deste estudo sugerem que o tipo de equipamento rotatório utilizado em cirurgia bucomaxilofacial não interfere no reparo ósseo. In oral surgery, the quality of bone repair may be influenced by several factors that can increase the morbidity of the procedure. The type of equipment used for ostectomy can directly affect bone healing. The aim of this study was to evaluate bone repair of mandible bone defects prepared in rabbits using three different rotary devices. Fifteen New Zealand rabbits were randomly assigned to 3 groups (n=5) according to type of rotary device used to create bone defects: I - pneumatic low-speed rotation engine, II - pneumatic high-speed rotation engine, and III - electric low-speed rotation engine. The anatomic pieces were surgically obtained after 2, 7 and 30 days and submitted to histological and morphometric analysis. The morphometric results were expressed as the total area of bone remodeling matrix using an image analysis system. Increases in the bone remodeling matrix were noticed with time along the course of the experiment. No statistically significant differences (p>0.05) were observed among the groups at the three sacrificing time points considering the total area of bone mineralized matrix, although the histological analysis showed a slightly advanced bone repair in group III compared to the other two groups. The findings of the present study suggest that the type of rotary device used in oral and maxillofacial surgery does not interfere with the bone repair process. Sacred Heart University Department of Oral Surgery Federal University of São Paulo Department of Health Sciences UNIFESP, Department of Health Sciences SciELO