Digital evaluation of Bolton's tooth size discrepancies among different malocclusions categories of Egyptian adolescent orthodontic population: A retrospective study.

OBJECTIVE: This retrospective investigation aimed to compare Bolton's ratios among different malocclusion groups of Egyptian adolescent orthodontic patients with original Bolton's standards. MATERIALS AND METHODS: Pre-treatment dental casts of 588 Egyptian subjects, 290 males and 298 females with mean age 16.7±2.2 years, were randomly selected and classified into 220 class I (108 males and 112 females), 230 class II (112 males and 118 females), and 138 class III (68 males and 70 females) groups. Mesiodistal widths from first molar to first molar were measured on 3-dimensionally scanned models via software and ratios were calculated. Two-way analysis of variance compared ratios as a function of skeletal classification and gender. Additionally, percentages of significant discrepancy outside 2 standard deviations (SDs) were calculated. RESULTS: The anterior mean ratio for the total sample were higher (79.4±4.7) and overall mean ratio was lower (90.1±5) than Bolton's standards. The differences between the obtained and standard values were statistically significant (P<0.001). However, there were no significant differences in either anterior ratio (P=0.637) or overall ratio (P=295) regarding gender. Class I cases showed the highest mean anterior ratio of 80±5.7 whereas class II and class III cases had the lowest ratio of 78.5±4.6 and 78.7±3.5, respectively. Concerning overall ratio, class III subjects had the highest ratio of 91.8±2.6 with no substantial distinction from class II cases (90.2±4.7) but was significantly different from class I cases that demonstrated the lowest ratio (89.7±5, P=0.020). High percentages of patients displayed clinically significant tooth size discrepancies (TSD), exceeding either above or below 2SD of Bolton's values, which were more marked in the anterior ratio. These were 25.2% and 7.4% for anterior ratio and 3.4% and 15.4% for overall ratio. CONCLUSIONS: Tooth size ratios of Egyptian orthodontic patients are generally different than the original Bolton's standards. Patients with class I and class III malocclusions had greater anterior and overall ratios than those with class II malocclusions with no considerable gender differences in either ratio.

Three-Dimensional Assessment of Mandibular Condylar Volume and Position Subsequent to Twin Block Functional Therapy of Skeletal Class II Malocclusion Accompanied by Low-Level Laser Therapy.

This study aimed to evaluate and compare the effect of low-level laser therapy (LLLT) on mandibular condylar volume and position following treatment of a Class II malocclusion with a twin block (TB) appliance employing cone beam computed tomography (CBCT). Twenty-four growing patients, aged 9-12 years, were randomly allocated into control and laser groups. All patients were treated with a TB appliance. The patients in the laser group were treated weekly with a gallium-aluminum-arsenide (GaAlAs) diode laser around the temporomandibular joint (TMJ) region for three months. CBCT images were obtained before and after TB therapy and the changes in TMJ and skeletal variables were evaluated and compared among and between the groups. In the laser group, the condylar volume of the right and left sides significantly increased by 213.3 mm3 and 231.2 mm3, respectively (p < 0.05), whereas in the control group it significantly increased by 225.2 mm3, and 244.2 mm3, respectively (p < 0.05), with forward and lateral positioning of both sides. Furthermore, effective mandibular, ramus, and corpus lengths were increased, which were not significant between the groups. Low-Level Laser therapy accomplished no considerable effect on mandibular condylar volume and position following the functional orthopedic treatment of skeletal Class II malocclusions using a TB appliance.