Relation of Lower Last Molar Teeth With Mandibular Fractures

Could mandibular fractures lead to obstructive sleep apnea?

OBJECTIVE

To detect and assess obstructive sleep apnea (OSA) before and after repair of different types of mandibular fractures.

METHODS

In patients with traumatic isolated mandibular fractures who were indicated for open reduction and internal fixation (OR/IF), polysomnography (PSG) was done before and 3 months after surgery.

RESULTS

Of 51 patients (80 mandibular fractures), fractures were unilateral in 29 patients (56.9%) and bilateral in 22 patients (43.1%). PSG was normal in 33 patients (64.7%), and OSA was detected in 18 cases (35.3%); all had bilateral fracture. Mild OSA was reported in 9 cases (17.65%), and moderate OSA was detected in 9 cases (17.65%). Three months after OR/IF of the fractures, successful reduction was obtained, and PSG was within normal limits in all patients.

CONCLUSION

Bilateral mandibular fractures often lead to OSA, which could be cured with proper OR/IF of the fractures. OSA is not encountered in unilateral fractures.

Do Mandibular Third Molars Play a Role in Fractures of the Mandibular Angle and Condyle?

INTRODUCTION

The relationship between impacted mandibular third molars with angle and condylar fractures is subject of many publications, yet their conclusions differ widely, hence the authors wanted to investigate this topic in their patients.

METHODS

The authors designed a retrospective study including 241 patients who presented with angle and/or mandibular condyle fractures over a 13-year period at the authors' institution. The study variable was the presence/absence of third molars. The authors used the Pell and Gregory system to classify their position, whereas the angulation was classified using Archer classification. The outcome variables were the presence of angle and condylar fractures. Other study variables included fracture etiology.

RESULTS

Assaults were the most frequent cause of angle fractures (62.7%), whereas falls were mostly responsible for condylar fractures (79.6%). Angle fractures were mostly isolated (66.3%), whereas condylar fractures were mostly associated with other fractures (62.6%). The majority of the angle fractures occurred in patients with third molars (63.6%), on the contrary the majority of the condylar fractures occurred in patients without mandibular third molars (78.3%). Angle fractures were mostly associated with fully erupted or superficially impacted third molars (90,9%). Finally in the presence of mesioangulated third molars, condylar fractures did not happen in 83.8% of patients.

CONCLUSIONS

According to the authors' findings, fully erupted or superficially impacted mandibular third molars are a risk factor for angle fractures but at the same time a protective factor for the condyle. On the contrary, the absence of mandibular third molars "strengthens" the angle and represents a risk factor for condylar fractures.

The Relation Between Morphometric Features and Susceptibility to Mandibular Angle Fractures

The study was aimed to determine possible relations between skeletal morphologic parameters to mandibular angle fractures. Retrospective study of 100 patients suffering from mandibular fractures and treated in the Rambam Health Care Campus between the years 2013 and 2017 was conducted. Predictor variable was facial skeletal morphologic features as derived from the measurements. Outcome variable was mandibular angle fractures. About 42 patients suffered from angle fractures. Gonial angle (131.3° versus 118.1°), condylar neck width (8.3 mm versus 6.8 mm sagittaly and 7.1 mm versus 5.8 mm horizontally), and wisdom tooth prevalence and impaction were positively correlated to the fracture. Ramus height (48.3 mm versus 53.4 mm) was negatively correlated to angle fractures. Many reports in the literature show positive relations between impacted 3rd molars and angle fractures, yet only sporadic reports describe relations between facial fractures and facial features. Our results showed the predictable positive relation between angle fractures and 3rd molar prevalence and impaction. Yet surprisingly, we found unequivocal significant positive correlation between angle fractures to gonial angle and condylar neck width and negative correlation to ramus height. Based on the correlation to the gonial angle and ramal height, it is concluded that enlarged anterior vertical growth is a predictor for angle fractures, as are condylar neck width, and wisdom teeth.

Does the angulation of the mandibular third molar influence the fragility of the mandibular angle after trauma to the mandibular body? A three-dimensional finite-element study

The relationship between mandibular third molar (M3) angulation and mandibular angle fragility is not well established. The aim of this study was to evaluate the impact of M3 angulation on the mandibular angle fragility when submitted to a trauma to the mandibular body region. A three-dimensional (3D) mandibular model without M3 (Model 0) was obtained by means of finite-element analysis (FEA). Four models were generated from the initial model, representing distoangular (Model D), horizontal (Model H), mesioangular (Model M) and vertical (Model V) angulations. A blunt trauma with a magnitude of 2000 N was applied perpendicularly to the sagittal plane in the mandibular body. Maximum principal stress (P_max) (tensile stress) values were calculated in the bone. The lowest P_max stress values were noted in Model 0. When the M3 was present extra stress fields were found around marginal bone of second molar and M3. Comparative analysis of the models with M3 revealed that the highest level of stress was found in Model V, whereas Model D showed the lowest stress values. The angulation of M3 affects the stress levels in the mandibular angle and has an impact on mandibular fragility. The mandibular angle becomes more fragile in case of vertical impaction when submitted to a trauma to the mandibular body region.