Abstract
BackgroundThe bone thickness of the human mandibular ramus is an important parameter in mandibular surgeries. The aim of this study was to systematically measure the bicortical bone thickness, the ramus dimensions and the position of the lingula. The measurements were tested on significant correlations to the patients’ parameters.MethodsBased on CBCT scans 150 rami were reconstructed as 3D polygon surfaces. An anatomical grid was adapted to the ramus surface to mark the bone thickness measurement points and to achieve comparability between the measurements on different mandibles. The bone thickness, ramus height, ramus width and the gonion angle were measured. A cluster analysis was performed with these parameters to identify clinically relevant groups with anatomical similarities.ResultsThe median distribution of the bone thickness was calculated and visualized in a pseudo-colour map. The mean ramus height was 44.78 mm, the mean width was 31.31 mm and the mean gonion angle was 124.8°. The average distance from the lingula to the dorsal tangent was 53% of the total width and its distance to the caudal tangent was 65% of the total height. Significant correlations between the bone thickness and the ramus proportions could be identified. Age and sex had no significant influence on the mean bone thickness. The measured rami could be divided into two groups by cluster analysis.ConclusionThe dimensions of the human mandibular ramus can be determined from 3D reconstructed surface models from CBCT scans. Measurements could be made comparable by applying an anatomically oriented grid. A cluster analysis allowed the differentiation of two groups with different bone thickness distributions and geometries, which can be used for the optimization of osteosynthesis systems and their precision of adaptation to different ramus morphologies.
Highlights
The bone thickness of the human mandibular ramus is an important parameter in mandibular surgeries
A large variability of the ramus morphology can be observed in clinical practice. It is primarily determined by the ramus height, width, gonion angle and the position of the lingula as well as the bone thickness, which all will be examined in more detail in this study
The accuracy is consistent with the accuracy of the CBCT scans, which is limited by the voxel size
Summary
The bone thickness of the human mandibular ramus is an important parameter in mandibular surgeries. A large variability of the ramus morphology can be observed in clinical practice It is primarily determined by the ramus height, width, gonion angle and the position of the lingula as well as the bone thickness, which all will be examined in more detail in this study. The position of the lingula plays an important role in determining the osteotomy line in sagittal and horizontal mandibular osteotomies [3] and the bone thickness seems to be an indicator for the susceptibility to complications during osteotomies [4]. Various studies have been measuring the bone thickness of the ramus at individual points: Susilo et al [4] measured the bone thickness of the ramus at one point at the level of the lingula as a guide for performing bilateral sagittal split osteotomy in orthognathic surgery and have put their results in relation to the sex and age of the person examined. To investigate the application of the lag screw technique according to Eckelt for the treatment of condyle fractures, variable morphologies of the mandibular ramus were shown in the coronal plane by Welk et al [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
