The Influence of the Gonial Angle on the Initial Biomechanical Stability of the Plate Osteosynthesis in Polyurethane Mandibles With Angle Fractures

The biomechanical stability of miniplate osteosynthesis configurations in bilateral mandibular angle fractures

PURPOSE

The present study investigated the biomechanical stability of three miniplate osteosynthesis configurations used for internal fixation of bilateral mandibular angle fracture (BMAF).

METHODS

Standard fracture lines were created in 72 polyurethane mandibles and stabilized with 2.0-mm, 4-hole standard titanium miniplates and monocortical screws. The group descriptions and miniplate configurations were: 2Plates (1-1), 3Plates (1-2) and 4Plates (2-2). The mandibles were subjected to either incisal or molar loads (from both sides in the 3Plates group) up to a force of 120 N. The displacements of the constructs were recorded at each force increment of 10 N. ANOVA and Tukey's post-hoc tests were used for statistical analysis.

RESULTS

The 2Plates group showed higher displacement under both loading conditions (P < 0.05 for each). The same group reached displacement levels of 1 mm and 3 mm during molar loading and 1 mm, 3 mm, and 5 mm during incisal loading at lower force magnitudes relative to others (P < 0.05 for each).

CONCLUSION

Bone-plate constructs for BMAFs stabilized with three or four standard miniplates are more likely to provide similar resistance when subjected to incisal or molar loads, in contrast to the two-miniplate configuration, which is relatively more prone to displacement.

Correlation of radiomorphometric indices of the mandible and mandibular angle fractures

This study assessed the correlation of radiomorphometric indices of the mandible and mandibular angle fractures (MAFs) in an Iranian population. This retrospective study was conducted on 3D computed tomography (CT) scans of 118 patients between 18 to 60 years. The images were divided into two groups with MAFs and other types of mandibular fractures (non-MAF). The gonial angle, ramus height, condylar neck width, minimum ramus width, and mandibular length were all measured using MARCO PACS software. Age, gender, and presence and eruption status of third molar at the fracture side were all recorded. The correlation between these parameters and MAF was analyzed using R software (alpha = 0.05). Of all patients, 41 samples had MAF. The two groups were not significantly different regarding the mean age and gender (P > 0.05). The mean size of gonial angle and ramus height in the MAF group were significantly larger, and smaller than the corresponding values in the non-MAF group, respectively (P < 0.001). The median minimum ramus width in the MAF group was significantly smaller than that in the non-MAF group (P = 0.001). Patients with a large gonial angle had 6.6 times higher odds of MAF compared with other fracture types (P = 0.046). Condylar neck width, mandibular length, and erupted third molars had no significant correlation with type of fracture. Presence of impacted third molar increased the odds of MAF by 5.55 times.

Patients with a large gonial angle, short ramus height, minimum ramus width, and impacted third molar are more susceptible to MAF. Surgeons can use these indices to predict the risk of MAF in trauma patients with such facial characteristics, and make a diagnosis by radiographic modalities.

Magnitude of Gonial Angle Influence on the Commonness of Mandibular Angle Fractures

Background:

The aim of the study was to review the literature on the influence of gonial angle on mandibular angle fracture. The present systematic review addresses the following focus question: Does the magnitude of gonial angle influence the incidence of mandibular angle fractures?

Materials and Methods:

Electronic and manual literature searches were conducted on databases: PubMed/MEDLINE, Embase, Science direct, the Cochrane Library, and clinicaltrials.gov for studies published up to August 2019 to collect information about the effect of gonial angle, a skeletal morphological parameter with an incidence of fracture of the angle of the mandibular arch. Systematic literature review was performed to identify studies evaluating the effect of gonial angle in patients suffering from mandible fractures. Large retrospective studies were included and case reports were excluded.

Results:

Fifteen hundred articles published before August 2019 were identified. One hundred and sixteen articles met the inclusion criteria. Two articles remained when exclusion criteria were applied. As measured in the two included studies containing 280 panoramic radiographs of mandibular fractures, the mean gonial angle of patients in the angle fracture group ranged from 126.8° ± 7.9° to 128.5° ± 5.4°. The mean gonial angle of patients in the nonangle fracture group ranged from 118.5° ± 4.4° to 122.3° ± 4.9°. The mean gonial angle of patients in the angle fracture group displayed a range from 118.9° to 134.7° (confidence interval [CI] 95% 5.89–8.05), whereas the mean gonial angle of patients in nonangle fracture group displayed a range from 114.1° to 127.2° (CI 95% 3.89–4.95).

Conclusion:

A high gonial angle is an important factor influencing the occurrence of mandibular angle fractures owing to the poorer quality of bone and reduced height at the ramus angle region, all of which necessitate a modification of osteosynthesis techniques.