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The aim of this study was to histologically evaluate and compare the effects of the systemic administration of L-thyroxine (TX) and doxycycline (DX) on orthodontically induced root resorption, Twenty-eight male 50- to 60-day-old Wistar rats were used. Seven rats served as the baseline control. Seven animals received TX (20 μg/kg bodyweight/day) and seven DX (1.2 mg/kg bodyweight/day), by means of a mini-osmotic pump implanted subcutaneously. Seven rats were separated as a sham, in order to evaluate the pure effect of the surgical procedure on the animals' health. Tooth movement (TM) was achieved with a continuous force of 50 g by placing Elgiloy coil springs between the right maxillary first molar and incisors for 14 days. The animals were sacrificed and specimens containing the appliance and maxillary tooth-bearing segments were processed for light microscopy. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. To evaluate the resorptive changes on the molar root surface of each group, scanning electron microscopy (SEM) examinations were also carried out. Statistical evaluation of root resorption percentages was performed using Kruskal-Wallis analysis of variance test. Multiple comparisons were determined by the Student-Newman-Keuls method. The level of significance was set at P < 0.05. Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.32 ± 0.25 in the TX and 0.26 ± 0.06 in the DX groups and 2.19 ± 0.86 in the control. Statistically significant inhibition of root resorption was determined both in the TX and DX groups (P < 0.001) on the TM side. There was no statistically significant difference in relative root resorption between the TX and DX groups. Systemic administration of TX and DX demonstrated similar effects on root resorption in rats and may have inhibitory effects on orthodontically induced resorptive activity.

Objective: To evaluate the condylar and ramal mandibular asymmetry in a group of patients with Class II subdivision malocclusion to identify possible gender differences between male and female subjects. Materials and Methods: Mandibular asymmetry measurements (condylar, ramal, and condylarplus-ramal asymmetry values) were performed on the panoramic radiographs of 80 subjects (34 male and 46 female). The study group consisted of 40 Class II subdivision patients (18 male and 22 female; mean age 14.53 Ϯ 3.14 years). The control group consisted of 40 subjects with normal occlusion (16 male and 24 female; mean age 14.43 Ϯ 3.05 years). The Kruskal-Wallis test was used to determine the possible statistically significant differences between the groups for condylar, ramal, and condylar-plus-ramal asymmetry index measurements. Identified differences between groups were further analyzed using the Mann-Whitney U-test at the 95% confidence interval (P Ͻ .05). Results: No gender-related difference was found for any of the asymmetry indices. Comparison of condylar, ramal, and condylar-plus-ramal asymmetry index values and gonial angle measurements for Class I and Class II sides in the Class II subdivision group and for right and left sides in the Class I group showed no statistically significant differences. However, the Class II subdivision group has longer values for condylar, ramal, and condylar-plus-ramal height measurements and only these differences were statistically significant (P Ͻ .001). Conclusions: Except for condylar ramal and condylar-plus-ramal height measurements, Class II subdivision patients have symmetrical condyles when compared to normal occlusion samples according to Habbet's mandibular asymmetry indices.

The aims of this study were to evaluate condylar, ramal, and condylar plus ramal mandibular vertical asymmetry in a group of cleft lip and palate (CLP) patients and compared with subjects with a 'normal' occlusion. Mandibular asymmetry index (condylar, ramal, and condylar plus ramal) and gonial angle measurements were examined on panoramic radiographs. The study groups comprised 20 unilateral cleft lip and palate (UCLP) patients (10 males and 10 females; mean age 13.03 +/- 3.33 years), 20 bilateral cleft lip and palate (BCLP) patients (10 males and 10 females; mean age 13.73 +/- 3.53 years), and a control group of 20 subjects (9 males and 11 females; mean age 14.35 +/- 2.46 years) with a normal occlusion. Kruskal-Wallis one-way analysis of variance was used to determine statistically significant differences between the groups for condylar, ramal, and condylar plus ramal asymmetry index measurements at the 95 per cent confidence interval. None of the investigated groups showed statistically significant gender differences for posterior vertical height measurements (P > 0.05). Asymmetry indices were similar, with no statistically significant differences found in any of the groups. However, gonial angle showed statistically significant differences (P < 0.05) in the UCLP group and condylar height (CH) in the BCLP patients (P < 0.001). Except for CH measurement in the BCLP group, CLP patients have symmetrical mandibles when compared with a normal occlusion sample.

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