Evaluation of condyle position in patients with Angle Class I, II, and III malocclusion using cone-beam computed tomography panoramic reconstructions

Position and Dimensions of the Mandibular Condyle in Various Anterior-Posterior Skeletal Patterns: A CBCT Imaging Study in a Sample of Iranian People

Purpose: The aim of this comparative observational study is to evaluate and compare the size and position of the condyle among male and female patients with different skeletal patterns in the anterior-posterior dimension using cone beam computed tomography (CBCT) images. Materials and Methods: CBCT images of 120 patients, all prepared for other treatment purposes under the same conditions, were included in the study. The patients were classified into three groups-class I, class II, and class III-based on ANB angles and Wits analysis. The size of the condyle was measured in terms of width, height, and length. The position of the condyle was assessed by measuring the superior joint space (SS), anterior joint space (AS), and posterior joint space (PS) on the right and left sides separately. The measurements and results were analyzed using analysis of covariance (ANCOVA) and Bonferroni analysis. A statistical significance level of p  < 0.05 was considered. Results: The study found no statistically significant differences in the size of the SS and AS (p = 0.481 and p = 0.392, respectively) across different skeletal patterns. However, the size of the PS was significantly greater in class I subjects compared to class III subjects (p = 0.015). There were no statistically significant differences in condyle height and width among the different skeletal patterns (p = 0.367 and p = 0.720, respectively). In contrast, condyle length was statistically significant in class II individuals (p = 0.002) and was the lowest among the other skeletal pattern groups. Conclusions: Based on the results obtained, class I individuals have lower PS values compared to class III individuals. Additionally, class II individuals have shorter condyle lengths compared to those in class III and class I.

A proposed novel digital condylar position adjustment technique to help restore a normal disc-condyle relationship

Objectives

To demonstrate a novel digital technique that enables real-time visualisation of occlusal transfer and adjustment of condyle position, to (1) improve the repeatability of occlusal transfer and the accuracy of condyle position adjustment and (2) be clinically effective in helping to restore the disc-condyle relationship.

Materials and methods

Three participants were included in the study and underwent facebow transfers using two different methods. The digital method used patient-related three-dimensional imaging data matched with digital dental casts for occlusal transfer. The conventional method used anatomical facebows. The condylar position was adjusted based on occlusal transfer results. The results were evaluated and compared in three dimensions. In addition, clinical application data from 36 patients were analysed before and after condylar position adjustment. Statistical significance was set at p < 0.05.

Results

Differences in the spatial positions of the three anatomical structures reproduced by both methods were statistically significant (p = 0.000). After adjusting the rotation of the condylar position, the positional deviation of the condylar point along the X- and Z-axes was significantly lower in the digital group (p < 0.05). After adjustment for translation (X and Z), the positional deviation showed no difference along the X- and Z-axes (p > 0.05) but a significant difference along the Y-axis (p < 0.001).

Conclusion

A novel digital technique for occlusal transfer and condylar position adjustment was presented. This technique simplifies clinical practice, improves the accuracy of results, and can help restore a normal disc-condyle relationship.

Influence of CBCT-derived panoramic curve variability in the measurements for dental implant planning

OBJECTIVE

To investigate whether the curve markings performed prior to panoramic and cross-sectional reconstructions can influence the planning of oral implants.

METHODS

Twenty oral radiologists landmarked the reference panoramic curves in 25 CBCT scans of the mandible. Bone height was measured on the resulting cross-sectional slices in the edentulous region of the lower first molar. The following data were recorded: (1) number of landmarks used to build each reference curve; (2) shape of the reference curve (inverted "U", inverted "V" or "horseshoe"); and (3) measurement in the first molar region. The data were assessed for variability based on the number of landmarks, the shape of the reference curve, and the measurements obtained.

RESULTS

The number of landmarks used to guide the panoramic reconstruction varied among radiologists (p < 0.05), but most of them draw curves in inverted "U" shape (68-100%). The reproducibility of the measurements taken in the edentulous mandibular first molar region was excellent (84.7%). The number of landmarks and the shape of the curve did not have a significant influence on the reproducibility of the measurements (p > 0.05).

CONCLUSION

Variations of the operator-dependent steps during the panoramic reconstructions occur but do not play a significant part changing the measurements taken for oral implant planning.

Assessment of the Morphology and Degenerative Changes in the Temporomandibular Joint Using CBCT according to the Orthodontic Approach: A Scoping Review

BACKGROUND

Available knowledge about disorders of temporomandibular joint structures and their association with orthodontic variables are still lacking.

OBJECTIVES

This article is aimed at to identifying studies and presenting current information on the relationship between morphology diversity and the occurrence of degenerative changes in structures of the temporomandibular joint (TMJ) assessed by cone-beam computed tomography (CBCT) in the context of craniofacial morphology and malocclusion. Search Methods. The review was conducted by analyzing the PubMed (including Medline), Cochrane Library, Web of Science, and Scopus electronic databases up to November 2021 using two different comprehensive search strategies based on keywords as well as additional manual searches. Eligibility Criteria. Selection of the literature was carried out according to the PRISMA-ScR checklist. Methodological quality of the selected studies was evaluated using JBI Critical Appraisal Tool.

RESULTS

The electronic databases search revealed 3331 records. After applying the eligibility criteria and JBI assessment, a total of 33 studies were extracted and selected to the study. The review was divided into 4 parts, in which the following correlations were assessed in terms of orthodontic variables: TMJ degenerative changes, joint space and condylar position, condylar shape, TMJ articular eminence, and fossa.

CONCLUSIONS

Skeletal and dental class II malocclusion with a retrognathic mandible, a hypodivergent skeletal pattern with a steep mandibular plane, and significant lateral mandibular displacement can be risk factors for developing radiographically detectable degenerative changes. Patients with skeletal and dental class III malocclusion as well as a hyperdivergent skeletal pattern may be at greater risk of TMD occurrence compared with other groups. Further studies are necessary to clarify the relationship between the position of the condylar processes and the presence of degenerative changes in the temporomandibular joints among orthodontic patients.

Angle's Classification-A Prosthodontic Consideration: Best Evidence Consensus Statement

PURPOSE

This Best Evidence Consensus Statement evaluated the existing Angle's classification clinical literature to determine if the Angle's classification as historically determined in maximum intercuspal position (MIP) with hand held casts is coincident with the centric occlusion (CO) determined Angle's classification. In addition, it explored the value of using Angle's classification for edentulous patients MATERIALS AND METHODS: The search strategy was related to the focus questions and limited to Meta-analyses, Systematic Reviews (SR), Randomized Controlled Trials (RCT) and Clinical Trials. Searches were completed using the term Angle's classification and Boolean Modifiers (AND) with the key terms: dental occlusion, dental occlusion centric, centric occlusion, centric relation, maximal intercuspation, MIP, intercuspal position, and edentulous patient, retrognathia, determination, and prognathia. Additional related articles were culled from the reference lists in the articles found in the PubMed searches.

RESULTS

The search identified 494 articles related to the selected terminology. Titles were reviewed and selected if related to the focus questions for further review. Seven papers could be identified that addressed the specifics of the questions.

CONCLUSIONS

There is evidence that the Angle's classification for many patients will change when recorded in CO compared to the historical MIP determination/definition. A different Angle's classification recorded in CO is potentially a significant diagnostic finding for patients needing complete mouth rehabilitation. The current definitions of Angle's Classification are not useful in the management of edentulous patients.