A review of biomechanical studies for mandibular angle fracture internal fixation

Mandible fractures correspond to 19-40% of all facial fractures. Among all mandible fractures, 12-30% are fractures of the mandibular angle. These fractures are mainly caused by sports activities, interpersonal violence and car accidents. The presence of the third molar and the thin transverse bone area seem to be responsible for the frequent involvement of the mandibular angle in facial fractures. Before the advent of antibiotics, a high frequency of infection was always associated after an open reduction in mandibular angle fractures. Wired osteosynthesis and maxillomandibular fixation (MMF) were traditional methods for fixing mandibular angle fractures. The limitation of both methods has influenced the development of new approaches for the treatment of mandibular angle fractures. Currently, osteosynthesis of mandibular angle fractures with plates and screws has become an effective treatment option. Several forms are described in the literature as: fixation of bone segments with a miniplate on the upper edge of the mandible, fixation with two miniplates, lag screw or by a single rigid plate on the lower edge of the mandible. The purpose of this study was to summarize the main characteristics of biomechanical studies such as the type of mandible source used, the plating techniques employed, the plate material, and the loading protocols used to evaluate the stability of the fixation methods. The Medline (PubMed) database was searched combining relevant terms and pertinent articles in English were included. Articles had to meet the following inclusion criteria: be in vitro biomechanical studies evaluating fixation methods for mandibular angle fractures. A total of 27 articles fulfilled the inclusion criteria. Synthetic mandibles (n=12), animal mandibles (n=9), and human cadaveric mandibles (n=5) were used as the sample source to perform the biomechanical analysis. One article used both synthetic and human cadaveric mandibles. Also, a variety of fixation techniques was described such as mini-plates, lag-screws, reconstruction plates, and three-dimensional plates. The materials of the bone plates used were: stainless steel, commercially pure titanium, titanium alloy or bioresorbable. However, there was inconsistency in reporting the materials and not all studies clearly stated the material of the bone plates. For the biomechanical analysis, there was a high variation among all studies regarding the loading protocols used. The same side of fixation, the anterior part of the mandible (central incisors) or the contralateral side were reported as the dentate regions in which the force was applied. For more than 2 decades, in vitro biomechanical studies have been used to help researchers and clinicians in the field of Oral and Maxillofacial Surgery to properly evaluate and compare the different devices and techniques available for the treatment of mandibular angle fractures. Also, biomechanical studies are important to answer questions on fatigue performance and fracture strength on the gross level.

125 The Fate of The Third Molar in The Line of a Mandibular Angle Fracture: A Retrospective Study at A Tertiary Centre

Aim: To evaluate the risk of complications associated with retaining or extracting an asymptomatic third molar in the line of an angle fracture. Aiming to seek a consensus whether third molars should be extracted or retained during surgical repair of mandibular angle fractures. Method A retrospective study was undertaken at the Queen Elizabeth Hospital, Birmingham. 150 patients across a span of three years underwent open reduction and internal fixation of mandibular angle fractures with third molar involvement. Patients were classified into two groups, tooth retention during angle fracture and tooth removal during angle fracture repair. Hospital records were evaluated to seek the rate of post-operative complications at follow-up Results 162 angle fractures were identified with ipsilateral wisdom teeth present. In 37 cases the wisdom tooth was removed during surgery. 6 complications (16.2%) occurred in this group necessitating a return to theatre. In 125 cases the wisdom tooth was left in-situ. Complications necessitating a return to theatre occurred in 14 cases (11.1%). Conclusions This study indicates that retention of wisdom tooth overall did not significantly increase the risk of complications associated with angle fractures (p = 0.42). Where wisdom tooth pathology was noted its retention was associated with complications requiring a return to theatre (X2=4.40, p = 0.036).

The influence of wisdom tooth impaction and occlusal support on mandibular angle and condyle fractures

This study aimed to analyze the relationship of the occlusal support together with the lower third molars to the mandibular fractures of the angle and condyle among patients in our medical institutions. This was a retrospective study that reviewed the medical records and radiographs of all patients treated for mandibular fractures from 2015 to 2019. The data collected by using picture archiving and communicating system. Only records with mandibular angle or condyle fractures were included. The dependent variable was the presence of the fractures of the mandibular angle or condyle. The independent variables were epidemiological data, third molar characteristics, existence or absence of occlusal support. The data was analyzed through Univariate logistic regression and multivariate logistic regression. From a total of 187 mandibular fractures, 44 presented mandibular angle fracture and 29 shown condyle fractures. The average age was 40.34 ± 13.47 years. The absence of occlusal support increased the chance of condyle fractures by 5.1 times (95% CI 1.61–17.29). The lack of occlusal support is more associated with condyle fractures than the presence of occlusal support, regardless of third molar presence and characteristics and other variables evaluated.