Three-Dimensional Changes of Condylar Position After Bimaxillary Surgery to Correct Skeletal III Malocclusion: Cone Beam Computed Tomography Voxel-Based Superimposition Analysis.

BACKGROUND: The stability of the condylar position within the first 3 months after orthognathic surgery in patients with skeletal Class III malocclusion is crucial for subsequent orthodontic treatment. PURPOSE: The purpose was to compare condylar positional changes 3 months after bimaxillary surgery to correct skeletal Class III deformities, utilizing the conventional two-dimensional combined with cone beam computed tomography voxel-based superimposition analysis. STUDY DESIGN, SETTING, SAMPLE: This retrospective cohort study included skeletal Class III patients undergoing bimaxillary orthognathic surgery at Khon Kaen University, Thailand, in 2020. Exclusion criteria were patients with temporomandibular disorder symptoms, facial asymmetry prior to the surgery, or surgical complications. EXPOSURE VARIABLE: The exposure variable was the timing, both preoperatively and 3 months postoperatively. This 3-month postoperative time point was chosen because complete healing of the bimaxillary surgery is expected by then, without any potential influence of condylar changes resulting from subsequent orthodontic treatment. MAIN OUTCOME VARIABLES: The outcome variables are condylar position measurement, joint space (mm), and axial condylar angle (degrees). COVARIATES: Demographics (age, sex) and surgical details (direction and amount of movement) were collected as covariates. ANALYSES: Statistical analysis of condylar positional changes and correlations was performed using paired t-test and linear correlation (P value < .05), respectively. RESULTS: The sample included 11 subjects (22 condyles), with a mean age of 24 ± 5.24 years. Both two-dimensional measurements and voxel-based three-dimensional superimposition showed significant changes in condylar position 3 months after bimaxillary surgery: inferior (0.45 ± 0.26 mm, P < .001), posterior (0.46 ± 0.39 mm, P = .003), lateral (0.38 ± 0.42 mm, P = .01) displacement, and inward rotation (5.21 ± 2.54°, P < .001). No significant correlation was found between jaw movement distance and condylar changes. CONCLUSION AND RELEVANCE: To our knowledge, this is the first study to report measures of condylar changes at 3 months, when complete healing of the osteotomies would be expected, using Le Fort I osteotomy for maxillary advancement combined with bilateral sagittal split ramus osteotomy for mandibular setback. These changes are small in magnitude and may be of little relevance to patient care.

Do various imaging modalities provide potential early detection and diagnosis of medication-related osteonecrosis of the jaw? A review.

OBJECTIVE: Patients with medication-related osteonecrosis of the jaw (MRONJ) often visit their dentists at advanced stages and subsequently require treatments that greatly affect quality of life. Currently, no clear diagnostic criteria exist to assess MRONJ, and the definitive diagnosis solely relies on clinical bone exposure. This ambiguity leads to a diagnostic delay, complications, and unnecessary burden. This article aims to identify imaging modalities' usage and findings of MRONJ to provide possible approaches for early detection. METHODS: Literature searches were conducted using PubMed, Web of Science, Scopus, and Cochrane Library to review all diagnostic imaging modalities for MRONJ. RESULTS: Panoramic radiography offers a fundamental understanding of the lesions. Imaging findings were comparable between non-exposed and exposed MRONJ, showing osteolysis, osteosclerosis, and thickened lamina dura. Mandibular cortex index Class II could be a potential early MRONJ indicator. While three-dimensional modalities, CT and CBCT, were able to show more features unique to MRONJ such as a solid type periosteal reaction, buccal predominance of cortical perforation, and bone-within-bone appearance. MRI signal intensities of vital bones are hypointense on T1WI and hyperintense on T2WI and STIR when necrotic bone shows hypointensity on all T1WI, T2WI, and STIR. Functional imaging is the most sensitive method but is usually performed in metastasis detection rather than being a diagnostic tool for early MRONJ. CONCLUSION: Currently, MRONJ-specific imaging features cannot be firmly established. However, the current data are valuable as it may lead to a more efficient diagnostic procedure along with a more suitable selection of imaging modalities.

Palatal Soft Tissue Thickness on Maxillary Posterior Teeth and Its Relation to Palatal Vault Angle Measured by Cone-Beam Computed Tomography.

OBJECTIVE: Analyzing palatal soft tissue thickness in cone-beam computed tomography (CBCT) images and evaluating the relationship between tissue thickness and palatal vault angulation. METHODS: Out of 1,737 CBCT images, fifty-six images met the inclusion criteria and were included in this cross-sectional study. The palatal vault angle on the maxillary first molar was measured and divided the images into 3 groups. The soft tissue thickness between the maxillary first premolar and second molar was measured at a distance of 3, 6, 7, 8, and 9 mm from the cementoenamel junction. All the image measurements were performed using CBCT-viewer software. RESULT: In this study, 56 CBCT images with full permanent maxillary posterior teeth and absence of light scattering were found. The mean age of the patients was 31.59 ± 13.92 years. The moderate and deep palatal vault angle patterns had the greatest and least prevalence, respectively. The average thickness on shallow, moderate, and deep palatal vault groups was 4.02 ± 0.58, 3.75 ± 0.73, and 3.43 ± 0.38 mm, respectively. Furthermore, the mean palatal mucosal thickness was statistically different between the deep and shallow palatal vault angle groups (p < 0.05, power of test 0.8). Based on the Pearson correlation coefficient, there was a negative correlation between the palatal mucosal thickness and palatal vault angle (p < 0.05, power of test 0.85). CONCLUSION: A negative correlation between the palatal mucosal thickness and palatal vault angle was observed. Furthermore, this study suggested that the shape of the palatal vault can be one of the supporting data for evaluating the graft dimensions.

Cone-beam computed tomography evaluation of curved root canals prepared using reciprocal rotary files and rotational rotary files.

AIM: The aim of this study is to compare curved root canal preparation between reciprocal rotary files and rotational rotary files in extracted teeth using cone-beam computed tomography (CBCT). The independent variable was the file type (reciprocal vs. rotary), and the primary outcome variable was the centering ratio of distance change after canal preparation. Secondary outcomes were canal transportation in extension and direction and the preparation time. MATERIALS AND METHODS: Forty mesial root canals from extracted permanent molars with curvatures ranging between 25° and 45° were randomly divided into 4 groups. Canals were prepared with two types of reciprocal rotary files (WaveOne and Reciproc) and two types of rotational rotary files (ProTaper and Mtwo), ten canals in each group. The root canals were scanned before and after preparation using CBCT. Group differences in outcome variables were tested using ANOVA and 5% type I error probability. RESULTS: At the middle third of canals, reciprocal rotary files yielded the least amount of deviation from the center in inner-outer furcal direction (P < 0.001). Transportation was shown from the original canal shape in all directions in four groups. The reciprocal rotary files took the least amount of preparation time as well (P < 0.001). CONCLUSIONS: Reciprocal files result in less transportation and working time than the rotational files.

Alveolar bone graft evaluation agreement using cone beam computed tomography in cleft lip and palate patients: a pilot study.

OBJECTIVE: To develop and test assessor agreement using a new cone beam computed tomography (CBCT) examination method for evaluating the outcome of alveolar bone grafts in cleft lip and palate patients. MATERIAL AND METHOD: Twenty patients with complete cleft lip and cleft palate who had undergone alveolar bone grafting with CBCT follow-up 3-6 months postoperative at the Faculty of Dentistry, Khon Kaen University were recruited into the study. Four trained clinical assessors (two orthodontists, an oral surgeon and an oral radiologist) had made a judgment of three outcome measurements: 1) cemento-enamel junction (CEJ) to marginal bone level of the teeth adjacent to the cleft site, 2) marginal bone level to root apex of the teeth adjacent to the cleft site, 3) labio-lingual alveolar bone grafted thickness. Repeat measurements were made by the same assessors. RESULTS: The Kappa values of intra-assessor agreements of each assessor were 0.82, 0.91, 0.91 and 1, respectively, while the inter-assessor agreements for the first and second time of determinations were 0.81 and 0.74. CONCLUSION: This CBCT method for scoring alveolar bone graft outcomes produced good agreement among four assessors, which suggests its potential use to evaluate the success of alveolar bone grafting. In the future, this new method of alveolar bone graft evaluation should be compared with the standard method for testing validity.

Evaluation of alveolar bone grafting in unilateral cleft lip and palate patients using a computer-aided diagnosis system.

PURPOSE: This study aimed to evaluate the trabecular bone changes after alveolar bone grafting in unilateral cleft lip and palate (UCLP) patients using a computer-aided diagnosis (CAD) system. MATERIALS AND METHODS: The occlusal radiographs taken from 50 UCLP patients were surveyed retrospectively. The images were categorized as: 50 images in group 0 (before bone grafting), 33 images in group 1 (one month after bone grafting), 24 images in group 2 (2-4 months after bone grafting), 15 images in group 3 (5-7 months after bone grafting), and 21 images in group 4 (8 or more months after bone grafting). Each image was grouped as either "non-cleft side" or "cleft side". The CAD system was used five times for each side to calculate the pixel area based on the mathematical morphology. Significant differences were found using a Wilcoxon signed ranks test or paired samples t test. RESULTS: The pixel area showed a significant difference between the "non-cleft side" and "cleft side" in group 0 (404.27±103.72/117.73±92.25; p=0.00), group 1 (434.29±86.70/388.31±109.51; p=0.01), and group 4 (430.98±98.11/366.71±154.59; p=0.02). No significant differences were found in group 2 (423.57±98.12/383.47±135.88; p=0.06) or group 3 (433.02±116.07/384.16±146.55; p=0.19). CONCLUSION: Based on the design of this study, alveolar bone grafting was similar to normal bone within 2-7 months postoperatively.