Discussion
condyle
SECONDARY, TMJ
Although the extensive literature on the potential condyle-mandibular adaptation of the chin cup is of interest, the conflicting outcomes urge high-quality studies that apply 3D imaging technology to the study of the TMJ, such as CBCT or CT scan.
Precise volumetric assessment can be affected by several variables, such as voxel size, patient position, and the characteristics of the software used for segmentation.
The influence of sex on the treatment outcomes was not accounted for in this study. Baccetti
Although the force applied from the chin cup, the volume and the superficial area of the mandible showed a significant increase. These changes could be secondary to simultaneous bone repositioning on most surfaces of the mandible.
The gonial angle showed a closing pattern at the end of treatment. This gonial angle change has also been reported in the literature.
The condyle's volume and superficial area increased significantly in both groups. It is important to highlight that even though no statistically significant differences were found, the overall changes in the condyles in the treatment group were smaller than in the control group. This change had been previously demonstrated by experimental studies showing a decrease in the condylar growth rate due to the compression force applied by the chin cup.
Another point that should be considered is the observed extensive standard deviation in the volumetric condylar change. The individual differences in the condyles' size, form, and growth cartilage; thus, growth magnitude should also be individually different. In turn, the chin cup force affects condyles variably in the clinical environment.
The distinguishing differences between the two groups involved most of the TMJ parts. The condyle was displaced posteriorly and superiorly in the chin cup group and accompanied by a posterior and posterior remodeling of the glenoid fossa. However, it showed lesser superior and posterior displacement than the condyle. The histological differences between the glenoid fossa and the condyles could be the reason for the non-equivalent changes.
In this context, Lee
The results indicated a decrease in the spaces of the joint, except for the anterior space. This may be attributed to the backward and upward forces applied from the chin cup, with the slow remodeling of the glenoid fossa, as mentioned previously.
The analysis of the changes in mandibular shape through 3D superimposition showed no differences between the two groups, except some inward changes were noticed in the symphysis region, which is indicated by the blue areas in the color mapping in
