A computed tomography-based analysis of the structure of the mandible according to age and sex

Abstract

Background: The primary objectives of mandibular surgery are to achieve optimal occlusion, low sensory disturbance, and adequate fixation with early movement. In-depth knowledge of the mandibular structure is required to achieve these goals. This study used computed tomography (CT) to evaluate the mandibular cortical thickness and cancellous space according to age and sex.Methods: We enrolled 230 consecutive patients, aged 20 to 50 years, who underwent CT scanning. The cortex and cancellous space centered around the inferior alveolar nerve (IAN) canal were measured at two specific locations: the lingula and second molar region. Statistical analysis of differences according to increasing age and sex was performed.Results: The t-test revealed that the cancellous space and cortical thickness differed significantly with respect to the threshold of 35 years of age. Both cortical thickness and cancellous space in the molar region were negatively correlated with age. Meanwhile, both cortical thickness and cancellous space in the lingula region showed a positive correlation with age. With respect to sex, significant differences in the cancellous space at the molar region and the cortical thickness at the lingula were observed. However, no further statistically significant differences were observed in other variables with respect to sex. The sum of each measurement on the mandibular body reflected the safe distance from the surface of the outer cortex to the IAN canal. The safe distances also showed statistically significant differences between those above and below 35 years of age.Conclusion: Knowledge of the anatomical structure of the mandible and of changes in bone structure is crucial to ensure optimal surgical outcomes and avoid damage to the IAN. CT examination is useful to identify changes in the bone structure, and these should be taken into account in the planning of surgery for older patients.

Measurement of Thickness at the Inferior Border of the Mandible Using Computed Tomography Images: A Retrospective Study including 300 Japanese Cases

“…CT or cone-beam CT (CBCT) mandibular measurements are common and have been used in orthodontic [ 17 ], temporomandibular joint [ 18 ], dental implant [ 19 , 20 ], oropharyngeal airway [ 21 ], inferior alveolar nerve [ 22 , 23 ], mandibular third molar [ 24 ], and coronoid foramina [ 25 ] studies. However, these were limited to the alveolar region [ 20 , 24 ], inferior alveolar nerve region [ 19 , 22 , 23 ], mandibular branch [ 17 , 25 , 26 ], and mandibular condyle [ 18 ]. The thickness of the mandible near the inferior margin is partly understood based on clinical experience, imaging studies [ 27 ], and anatomy [ 28 ]; however, such data are rarely reported in the literature.…”

“…CT or cone-beam CT (CBCT) mandibular measurements are common and have been used in orthodontic [17], temporomandibular joint [18], dental implant [19,20], oropharyngeal airway [21], inferior alveolar nerve [22,23], mandibular third molar [24], and coronoid foramina [25] studies. However, these were limited to the alveolar region [20,24], inferior alveolar nerve region [19,22,23], mandibular branch [17,25,26], and mandibular condyle [18].…”

Diagnosis of split fractures of the mandible in adults

“…This suggests a possible correlation between the relatively less intense impact on the mandible and the incidence of split fractures. The thickness of the mandibular cortex decreases after the age of 35 years [ 8 ]. Yet, in this study, there appeared to be a minimal correlation between cortical thickness and split fractures, as patients in their 20s and those in their 60s and 70s exhibited similar fracture patterns.…”

The complete anatomy of the mandibular lingula: a meta-analysis with clinical implications

“…Choi and Hur [58] claim that the maximal value from the occlusal plane can prevent injecting too deeply, thus preventing IAN block, in contrast to using the mean value as a point of reference. Nevertheless, preoperative scanning is a crucial step for the evaluation of the structure of the mandible prior to any invasive procedures [59]. With respect to the SSRO dentofacial correction procedure, the ML provides a convenient landmark for a safe horizontal osteotomy [7].…”