Mandibular angle fracture has the highest postsurgical complication and among all types of mandibular fracture . Angle fractures are the second most common mandibular fractures, after condylar fractures . The angle region is the first most frequent site for fractures caused by contact sports accidents, the second most common fractures caused by inter personal violence and the third most fractured region in road traffic accidents .
Mandibular angle fracture usually commences at the upper border of the mandible, where the anterior border of the ramus meets the mandibular body, usually in the third molar region, and extends downward to the inferior border or backward, in the gonial angle region . Mandibular angle fractures may be favourable or unfavuorable, depending on the direction of fracture line, in the horizontal and vertical planes, and the degree of displacement of the proximal and distal fractured segments .
The susceptibility of mandibular angle to fractures could be attributed to the anatomic weakness of this region, due to its abrupt curvature and changes in the direction of osseous trabeculae. Factors such as impacted third molars, reduced mandibular height, and poor bone quality could also reduce the strength of mandible, making it more susceptible to fracture. .
Gonial angle is an important angular measurement, used to assess the growth trend and pattern . Based on the degree of gonial angle, the mandible can be considered as having low or high angle . A high gonial angle indicates clockwise rotations of the mandible, whilst low gonial angle designates anticlockwise growth rotation of the mandible .
Radiographic examination employing cephalometric or panoramic radiographs is used in the clinical context to determine the gonial angle. The orthopantomograph is used in this investigation to locate the fracture site and measure the gonial, antegonial, and ramus heights. According to Abdul Rehman et al. , a panoramic radiograph allows for more precise measuring of the gonial area without the influence of superimposed structures seen in lateral cephalograms. Many investigations have found that the right and left gonial angles are essentially identical, with any deviations considered minor . As a result, the nonfractured side's gonial angle was taken into account in this investigation. The gonial angle has been found to be the most accurate measurement obtained from an orthopantomograph. This is most likely due to the fact that it is an angular rather than a linear measurement, and hence is unaffected by magnification .
The results of this study showed that the gonial angle of patients with unilateral angle fractures is 127.60 which is 6 degrees larger than the gonial angle of other mandibular fracture sites. In addition, 45% of angle fractures occurred in high angle cases and 47% of non-angle fractures occurred in the low angle cases The Cramer’s V correlation showed a medium effect of high gonial angle on the occurrence of mandibular angle fractures.
The findings of this study are consistent with the results of other studies. Panneerselvam et al , found that the gonial angle was 4.5° greater than other nonangle fractures. Dhara et al. , demonstrated that the gonial angle was 10.2° larger in the angle fractures as compared to non-angle fractures. Elias et al. , in a CT-based study, detected that the gonial angle of mandibular angle fractures was 13.2 ° greater than nonangle fractures. Semel et al. , discovered that angle fractures had a larger gonial angle than other fracture locations. Elavenil et al., also concluded that the gonial angle was 4.5° greater in angle fractures.
The higher vulnerability to angle fractures in high-angle patients was previously attributed to lower bite forces, which result in less cortical bone thickness at the angle region. Furthermore, it has been demonstrated that in high angle cases, the height of the mandible at the ramus and angle area is much lower than in normal persons . The current study found that ramus height and antegonial angle are considerably lower in high angle fracture patients than in normal and low angle cases.