Comparison of spheno-occipital synchondrosis maturation stages with three-dimensional assessment of mandibular growth.

BACKGROUND: This study aimed to compare spheno-occipital synchondrosis (SOS) maturation stages with a three-dimensional assessment of mandibular growth. METHODS: This is a cross-sectional study of a retrospective type, in which cone-beam computed tomography (CBCT) images of 500 patients aged 6 to 25 years (226 males and 274 females) were analyzed. The SOS was evaluated using the four-stage scoring system; completely open, partially fused, semi-fused, or completely fused. The SOS scoring and three-dimensional cephalometric measurements were analyzed by Invivo 6.0.3 software. Descriptive and analytical statistics were performed, and a P-value < 0.05 was considered statistically significant. RESULTS: There was a statistically significant difference in mandibular measurements among SOS maturation stages in both sexes (P < 0.05). The skeletal growth increments of mandibular variables across the SOS stages had higher mean differences between SOS stages 2 and 3 than those between stages 1 and 2 and stages 3 and 4 in both sexes. The mandibular growth curves increased with chronological age (earlier in females) and SOS maturation stages (mostly in stages 1, 2, and 3 than stage 4). CONCLUSIONS: The SOS maturation stages are valid and reliable mandibular skeletal indicators as evaluated with three-dimensional cephalometric mandibular measurements. The findings of growth increments and constructed growth curves of mandibular growth might be helpful in diagnosis and treatment planning.

Correlation between the three-dimensional maxillomandibular complex parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions.

OBJECTIVES: This study aimed to determine the three-dimensional (3D) correlation between maxillomandibular complex parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions. METHODS: This retrospective cross-sectional study included the CBCT scans of 368 patients with a mean age of 23.81 ± 3.01 years. The patients were classified into three groups (skeletal Class I, II, and III). Each class group was divided into three subgroups based on vertical growth patterns (hypo-, normo-, and hyperdivergent). The maxillomandibular complex was evaluated in the three planes using 16 skeletal measurements. Naso-, oro-, hypo-, and total pharyngeal airway spaces were assessed in terms of width, volume, surface area, and minimum constricted area (MCA). Two-way ANOVA followed by the Bonferroni post-hoc test were used. RESULTS: The nasopharyngeal airway space was significantly lowest regarding sagittal and lateral widths in the skeletal Class III patients, the lowest volume and surface area were in hyperdivergent patients, and MCA was the highest in Class II and hypodivergent patients. The oro- and hypopharyngeal sagittal width, volume, surface area, and MCA were the lowest in the hyperdivergent patients, and oropharyngeal lateral width and hypopharyngeal sagittal width were the highest in skeletal Class III. The total pharyngeal volume, surface area, and MCA were the lowest in the hyperdivergent patients, and skeletal Class II patients had the lowest MCA. CONCLUSIONS: The pharyngeal airway dimensions differ with various sagittal and vertical malocclusions. These differences could apply to diagnosis, treatment planning, and possible changes following orthodontic/orthopedic or surgical treatment.