IntroductionTo evaluate the accuracy of CAD/CAM generated splints in orthognathic surgery by comparing planned versus actual post-operative 3D images.MethodsSpecific planning software (SimPlant® OMS Standalone 14.0) was used to perform a 3D virtual Le Fort I osteotomy in 10 fresh human cadaver heads. Stereolithographic splints were then generated and used during the surgical procedure to reposition the maxilla according to the planned position. Pre-operative planned and postoperative 3D CT scan images were fused and imported to dedicated software (MATLAB®) 7.11.) for calculating the translational and rotational (pitch, roll and yaw) differences between the two 3D images. Geometrical accuracy was estimated using the Root Mean Square Deviations (RMSD) and lower and upper limits of accuracy were computed using the Bland & Altman method, with 95 % confidence intervals around the limits. The accuracy cutoff was set at +/− 2 mm for translational and ≤ 4° for rotational measurements.ResultsOverall accuracy between the two 3D images was within the accuracy cutoff for all values except for the antero-posterior positioning of the maxilla (2.17 mm). The translational and rotational differences due to the splint were all within the accuracy cutoff. However, the width of the limits of agreement (range between lower and upper limits) showed that rotational differences could be particularly large.ConclusionThis study demonstrated that maxillary repositioning can be accurately approximated and thus predicted by specific computational planning and CAD/CAM generated splints in orthognathic surgery. Further study should focus on the risk factors for inaccurate prediction.
We report a case of an asymptomatic healthy 49-year-old male patient with an incidental finding of enlargement of the right inferior alveolar nerve (IAN) canal (9 vs. 4 mm). After 2 years, follow-up magnetic resonance imaging (MRI) revealed no change in the findings. In addition, MR-based diffusion tensor imaging with tractography of the right and left mandibular nerves showed that the difference in size between the right and left nerves was caused by an increased number of nerve fibers in the right IAN. During the entire follow-up period of 4 years, the patient remained symptom-free. Therefore, we suggest that the enlargement in our patient was a pure anatomic variant. However, a multitude of conditions are known to produce the identical radiological appearance in conventional radiology, including benign and malignant tumors, vascular malformations, and inflammatory disorders. We describe these pathologies in more detail as well as the possibilities for examinations with different MRI sequences.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.