The aim of this study was to evaluate and compare the dentofacial effects of 1 week rapid palatal expansion (RPE) and activation-deactivation (A/D) RPE protocols with reverse headgear (RH). Two groups, each containing 15 subjects, were included in this study. In the RPE group (seven males and eight females, 11.94 ± 1.62 years), Hyrax screws were activated every 12 hours for 1 week. At the end of this period, RPE was stopped and the patients were instructed to wear the RH. In the A/D-RPE group (seven males and eight females, 11.34 ± 1.81 years), the screws were activated every 12 hours for 1 week. Subsequently, the screws were deactivated every 12 hours for 1 week followed by activation and deactivation for the following 2 weeks. After this protocol, the patients were instructed to use the RH. A total force of 700 g was applied to both groups for 16-18 hours/day for the first 3 months, for 12 hours/day for the second 3 months, and for 6 hours/day for the second 6 months. Lateral cephalometric films were taken before treatment (T1) and at the end of the first (T2) and second (T3) 6 months to evaluate the dentofacial changes. Intragroup differences of each landmark at T2-T1, T3-T2, and T3-T1 were analysed with a paired t-test (P < 0.016), and intergroup differences were compared with an independent t-test (P < 0.05). Anterior movement of point A (4.13 mm) for the A/D-RPE group was approximately twice of the RPE group (2.33 mm; P < 0.001). Backward movement of the mandible showed no significant difference between the groups. Anterior face height increases did not demonstrate significant differences between the groups. The pronounced anterior movement of point A demonstrates that the A/D-RPE procedure positively affects maxillary protraction.

The aim of this study was to compare the clinical performance of a self-etching primer (SEP) with a conventional two-step etch and primer [conventional method (CM)]. The chair time required for bonding was also evaluated. Thirty-seven patients (14 males and 23 females) with a mean age of 16 years 5 months were included in the study. Six hundred and seventy-two brackets were bonded by one operator using a split-mouth design, with either SEP (Transbond Plus) or CM (Transbond XT). Bracket failure rates were estimated with respect to bonding procedure, dental arch, type of tooth (incisor, canine, and premolar), and gender. The results were evaluated using the chi-square test. The survival rate of the brackets was estimated with Kaplan-Meier analysis. Bracket survival distributions with respect to bonding procedure, dental arch, type of tooth, and patient gender were compared with a log-rank test. Bond failure interface was determined with the adhesive remnant index (ARI). The failure rates were 0.6 per cent for both bonding procedures. The failure and survival rates did not show significant differences between the bonding procedures, upper and lower dental arches, or gender. However, premolar brackets displayed a higher bond failure rate and a lower survival rate than incisor and canine brackets (P < 0.05). The mean bracket bonding time per tooth with SEP was significantly shorter than with CM (P < 0.001). No significant difference was observed for the ARI scores (P > 0.05). The results of this in vivo, randomized, cross-mouth clinical trial demonstrated a high survival rate with Transbond Plus. This finding indicates that SEP can be effectively used for bonding of orthodontic brackets.

The results of this study indicate that the SEP (Transbond Plus) provides clinically acceptable bond strength values compared with the conventional method after thermocycling.

Adequate SBS was obtained with self-etching primer during the first 60 minutes (5, 15, 30 and 60 minutes) when compared with the conventional method. It is reliable to load the bracket 5 minutes after bonding using self-etching primer (Transbond Plus) with the light-cure adhesive (Transbond XT).

Objective:To compare the clinical performance of a self-etching primer (SEP) with a conventional two-step etch and primer method (CM). Materials and Methods: Study subjects were 39 patients with a mean age of 15 years 7 months. Six hundred and eighty-eight brackets were bonded by one operator with a split-mouth design, using Transbond Plus Self-Etching Primer or a conventional two-step etch and primer (Transbond XT). The survival rate of the brackets was estimated by the Kaplan-Meier analysis. Bracket survival distributions with respect to bonding procedure, dental arch, type of tooth (incisor, canine, and premolar) and patients' gender were compared using the log-rank test. Bond failure interface was determined using the Adhesive Remnant Index (ARI). Results: The bond failure rates of SEP and CM were 4.7% and 1.7%, respectively. A significant difference was found between the bonding procedures using the log-rank test (P Ͻ .05). Furthermore, canine and premolar teeth displayed a lower survival rate than incisor teeth (P Ͻ .05). Survival rates did not show significant differences between the upper and lower dental arches and patients' gender (P Ͼ .05). No significant difference was observed for ARI scores (P Ͼ .05). Conclusion: These findings indicate that the SEP (Transbond Plus) can be effectively used to bond orthodontic brackets.