Avaliação do comportamento mecânico de três diferentes tipos de osteossíntese em fratura de côndilo mandibular: análise por elementos finitos 3D

Pós-graduação em Odontologia - FOAR

Unerupted Lower Third Molar Extractions and Their Risks for Mandibular Fracture

As every surgical procedure extraction of third molars can result in several complications, among them the mandibular angle fracture. Predisposing factors for fracture should be analyzed during and after the surgery. This paper aims to discuss the predisposing factors to the occurrence of mandibular angle fractures during and after the procedure for third molars extraction, as well as surgical principles to avoid this complication.

Finite element evaluation of three methods of stable fixation of condyle base fractures

The surgical treatment of mandibular condyle fractures currently offers several possibilities for stable internal fixation. In this study, a finite element model evaluation was performed of three different methods for osteosynthesis of low subcondylar fractures: (1) two four-hole straight plates, (2) one seven-hole lambda plate, and (3) one four-hole trapezoidal plate. The finite element model evaluation considered a load applied to the first molar on the contralateral side to the fracture. Results showed that, although the three methods are capable of withstanding functional loading, the lambda plate displayed a more homogeneous stress distribution for both osteosynthesis material and bone and may be a better method when single-plate fixation is the option.

Spontaneous healing responses detected by cone-beam computed tomography of horizontal root fractures: a report of two cases

Horizontal root fractures (HRF) usually affect the anterior teeth as a result of trauma, and generally heal spontaneously, depending on the vitality of the pulp. Diagnosis based on clinical findings, sensitivity tests, and radiographic examination is important to determine the presence of a root fracture and to prevent a root fracture from passing unnoticed. Cone-beam computed tomography (CBCT) has been used successfully for diagnosis and prognosis imaging of root fractures and has proved to be superior to other radiographic methods. This study reports two cases of dental trauma caused by a collision and a sports accident. The patients suffered horizontal root fractures in the maxillary left central incisor and in the mandibular left central incisor. The diagnosis of root fracture was confirmed by cone-beam computed tomography (CBCT) images, which also demonstrated spontaneous healing of the fracture line. The repair occurred by interposition of connective tissue in the former case and by interposition of bone and connective tissue in the latter case. The final diagnoses of both cases were based on CBCT images, indicating the importance of a CBCT examination to reach a firm diagnosis and to follow the healing process of root fracture cases, avoiding unnecessary radical endodontic treatment.

Treatment of condylar fractures with an intraoral approach using an angulated screwdriver: Results of a multicentre study

Background This multicentre study aimed to investigate long-term radiographic and functional results following the treatment of condylar fractures using an angulated screwdriver system and open rigid internal fixation with an intraoral surgical approach. Methods Twenty-nine patients with a total of 32 condylar fractures were evaluated. The patients were investigated prospectively based on the following variables: age, sex, aetiology, side, location and classification of the fracture, degree of displacement, associated fractures, surgical approach, oral health status, type of osteosynthesis plate, duration of surgery, mouth-opening, complications, and duration of follow-up. Results The fractures were classified as subcondylar (n = 25) or condylar neck (n = 7). Mean patient age was 36.38 ± 16.60 years. The median duration of postoperative follow-up was 24.39 ± 13.94 months. No joint noise, weakness of the facial nerve, joint pain, or muscle pain was observed. An additional retromandibular approach was necessary to enable the treatment of one subcondylar fracture with medial displacement. Conclusion Subcondylar or condylar neck fractures with medial or lateral displacement can be treated using an intraoral approach with satisfactory results with the advantages of the absence of visible scarring, the avoidance of facial nerve injury, and the ability to obtain rapid access to the fracture.

Treatment of condylar fractures with an intraoral approach using an angulated screwdriver: Results of a multicentre study

Background: This multicentre study aimed to investigate long-term radiographic and functional results following the treatment of condylar fractures using an angulated screwdriver system and open rigid internal fixation with an intraoral surgical approach.Methods: Twenty-nine patients with a total of 32 condylar fractures were evaluated. The patients were investigated prospectively based on the following variables: age, sex, aetiology, side, location and classification of the fracture, degree of displacement, associated fractures, surgical approach, oral health status, type of osteosynthesis plate, duration of surgery, mouth-opening, complications, and duration of follow-up.Results: The fractures were classified as subcondylar (n = 25) or condylar neck (n = 7). Mean patient age was 36.38 +/- 16.60 years. The median duration of postoperative follow-up was 24.39 +/- 13.94 months. No joint noise, weakness of the facial nerve, joint pain, or muscle pain was observed. An additional retromandibular approach was necessary to enable the treatment of one subcondylar fracture with medial displacement.Conclusion: Subcondylar or condylar neck fractures with medial or lateral displacement can be treated using an intraoral approach with satisfactory results with the advantages of the absence of visible scarring, the avoidance of facial nerve injury, and the ability to obtain rapid access to the fracture. (C) 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Conservative Treatment of Comminuted Mandibular Fracture Involving Maxillomandibular Fixation With Miniplates

Bars and steel wires are the most commonly used methods to achieve maxillomandibular fixation, although there are numerous alternatives described for this same purpose. In cases of edentulous candidates for the conservative treatment of facial fractures, none of the conventional methods can be instituted for maxillomandibular fixation. Fixation in such cases is achieved with the aid of the total dentures of the patient or the confection of splints, but these methods lead to eating and oral hygiene problems. This article reports the case of an edentulous patient with a comminuted mandible fracture treated with a rarely described technique in which intermaxillary fixation was achieved with titanium miniplates.

Comparative study of bone repair in mandibular body osteotomy between metallic and absorbable 2.0 mm internal fixation systems. Histological and histometric analysis in dogs: a pilot study

The objective of this study was to compare the bone repair along a mandibular body osteotomy stabilized with 2.0 mm absorbable and metallic systems. 12 male, adult mongrel dogs were divided into two groups (metallic and absorbable) and subjected to unilateral osteotomy between the mandibular third and fourth premolars, which was stabilized by applying two 4-hole plates. At 2 and 18 weeks, three dogs from each group were killed and the osteotomy sites were removed and divided equally into three parts: the upper part was labelled the tension third (TT), the lower part the compression third (CT), and the part between the TT and CT the intermediary third (IT). Regardless of the treatment system, union between the fragments was observed at 18 weeks and the CT showed more advanced stages of bone repair than the TT. Histometric analysis did not reveal any significant differences among the 3 parts or systems in the distance between bone fragments at 2 weeks. Although at 18 weeks the proportions of newly formed bone did not differ among TT, IT and CT, significantly enhanced bone formation was observed in all sections for the metallic group. The patterns of repair were distinct between treatments.

Occurrence and types of dental injuries among patients with maxillofacial fractures

The aim of this retrospective study was to clarify the occurrence and types of dental injuries in 389 patients who had been diagnosed with facial fractures, and to analyze whether the occurrence of dental injury correlates to gender, age, trauma mechanism and type of facial fracture. Dental injuries were observed in 62 patients (16%). The most common type of injury was a crown fracture (48%). Dental injuries were multiple in most patients (63%). Almost half (48%) of all injured teeth were severely injured. Most injured teeth (61%) were in the maxilla. The incisor region was the most prevalent site in both the mandible (45%) and the maxilla (56%). The occurrence of dental injury correlated significantly with trauma mechanism and fracture type: motor vehicle accidents and mandibular fracture were significant predictors for dental trauma. The notable rate of dental injury observed in the present study emphasizes the importance of a thorough examination of the oral cavity in all patients who have sustained facial fracture. Referral to a dental practice for further treatment and follow up as soon as possible after discharge from hospital is fundamental.

Use of straight and curved 3-dimensional titanium miniplates for fracture fixation at the mandibular angle

PURPOSE: The aim of this follow-up study was to evaluate the clinical usefulness of a new type of 3-dimensional (3D) miniplate for open reduction and monocortical fixation of mandibular angle fractures. PATIENTS AND METHODS: In 20 consecutive patients, noncomminuted mandibular angle fractures were treated with open reduction and fixation using a 2 mm 3D miniplate system in a transoral approach. All patients were systematically monitored until 6 months postoperatively. Among the outcome parameters recorded were infection, hardware failure, wound dehiscence, and sensory disturbance of the inferior alveolar nerve. RESULTS: The mean operation time from incision to wound closure was 65 minutes. Two patients had a mucosal wound dehiscence with no consequences. None developed an infection requiring a plate removal. All but 2 patients had normal sensory function 3 months after surgery. Plate fracture occurred in one patient in whom a preceding surgical removal of the third molar had been the reason for the mandibular fracture. In the absence of clinical symptoms, the patient declined plate removal. On final follow-up, fracture healing was considered clinically complete in all patients. CONCLUSIONS: The 3D plating system described here is suitable for fixation of simple mandibular angle fractures and is an easy-to-use alternative to conventional miniplates. The system may be contraindicated in patients in whom insufficient interfragmentary bone contact causes minor stability of the fracture.

Dental injuries in association with facial fractures

PURPOSE: The aim of the study was to investigate the association between dental injuries and facial fractures. MATERIALS AND METHODS: We performed a prospective study of 273 patients examined at a level 1 trauma center in Switzerland from September 2005 until August 2006 who had facial fractures. Medical history and clinical and radiologic examination findings were recorded to evaluate demographics, etiology, presentation, and type of facial fracture, as well as its relationship to dental injury site and type. RESULTS: In 273 patients with dentition, we recorded 339 different facial fractures. Of these patients, 130 (47.5%) sustained a fracture in the non-tooth-bearing region, 44 (16%) had a fractured maxilla, and 65 (24%) had a fractured mandible. Among 224 patients with dentition who had a facial fracture in only 1 compartment, 140 injured teeth were found in 50 patients. Of 122 patients with an injury limited to the non-tooth-bearing facial skeleton, 12 sustained dental trauma (10%). In patients with fractures limited to the maxilla (n = 41), 6 patients had dental injuries (14.5%). In patients with fractures to the mandible (n = 61), 24 sustained dental injuries (39%). When we compared the type of tooth lesion and the location, simple crown fractures prevailed in both jaws. Patients with a fracture of the mandible were most likely to have a dental injury (39.3%). The highest incidence of dental lesions was found in the maxilla in combination with fractures of the lower jaw (39%). This incidence was even higher than the incidence of dental lesions in the lower jaw in combination with fractures of the mandible (24%). CONCLUSIONS: Knowledge of the association of dental injuries and maxillofacial fractures is a basic tool for their prevention. Our study showed that in cases of trauma with mandibular fracture, the teeth in the upper jaw might be at higher risk than the teeth in the lower jaw. Further larger-scale studies on this topic could clarify this finding and may provide suggestions for the amelioration of safety devices (such as modified bicycle helmets).

Complications with computer-aided designed/computer-assisted manufactured titanium and soldered gold bars for mandibular implant-overdentures: short-term observations

BACKGROUND Implant-overdentures supported by rigid bars provide stability in the edentulous atrophic mandible. However, fractures of solder joints and matrices, and loosening of screws and matrices were observed with soldered gold bars (G-bars). Computer-aided designed/computer-assisted manufactured (CAD/CAM) titanium bars (Ti-bars) may reduce technical complications due to enhanced material quality. PURPOSE To compare prosthetic-technical maintenance service of mandibular implant-overdentures supported by CAD/CAM Ti-bar and soldered G-bar. MATERIALS AND METHODS Edentulous patients were consecutively admitted for implant-prosthodontic treatment with a maxillary complete denture and a mandibular implant-overdenture connected to a rigid G-bar or Ti-bar. Maintenance service and problems with the implant-retention device complex and the prosthesis were recorded during minimally 3-4 years. Annual peri-implant crestal bone level changes (ΔBIC) were radiographically assessed. RESULTS Data of 213 edentulous patients (mean age 68 ± 10 years), who had received a total of 477 tapered implants, were available. Ti-bar and G-bar comprised 101 and 112 patients with 231 and 246 implants, respectively. Ti-bar mostly exhibited distal bar extensions (96%) compared to 34% of G-bar (p < .001). Fracture rate of bars extensions (4.7% vs 14.8%, p < .001) and matrices (1% vs 13%, p < .001) was lower for Ti-bar. Matrices activation was required 2.4× less often in Ti-bar. ΔBIC remained stable for both groups. CONCLUSIONS Implant overdentures supported by soldered gold bars or milled CAD/CAM Ti-bars are a successful treatment modality but require regular maintenance service. These short-term observations support the hypothesis that CAD/CAM Ti-bars reduce technical complications. Fracture location indicated that the titanium thickness around the screw-access hole should be increased.