The use of a chin cup improved the maxillomandibular base relationship in growing patients with Class III malocclusion but with little skeletal effect. The utilization of either force had the same effects, except that the higher force had a more pronounced effect in reduction of ramus height.

Purpose: This study was aimed to evaluate the effect of saliva and blood contamination on shear bond strength of metal brackets bonded with light cured cyanoacrylate adhesive. Material and methods: The study was conducted on 75 extracted upper first premolars. Metal orthodontic brackets were bonded to the buccal surfaces of the premolars using Smart bond LC adhesive. The teeth were divided into 5 equal groups. In group I no the teeth were not subjected to contamination. In Group II and III the same procedures were done as in in group I except that the etched enamel was contaminated by saliva and blood respectively for 15 seconds. In group IV and V the same procedures were followed as in group II and III except that the saliva and blood contamination were washed with water for 10 seconds. The shear bond strengths were recorded using universal testing machine. The amount of adhesive remaining on the tooth was evaluated after debonding. The collected data were statistically analyzed using One-way analysis of variance (ANOVA) and LSD tests. Results: The results revealed that no significant differences were found in the bond strength between the control group (without contamination), saliva contamination group without washing and saliva contamination group with washing (P>0.05). On the other hand, blood contamination significantly reduced the bond strength in comparison the saliva contamination or control groups (P<0.05). In addition, washing after blood contamination provided significantly higher bond strength than without washing (P<0.05). Conclusion: Saliva contamination had no pronounced deleterious effect on the bond strength of Smart bond LC. On the other hand, blood contamination had pronounced deleterious effect on the bond strength. However, washing with water significantly reduced this effect.

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Purpose To compare the microbial flora, alkaline phosphatase (ALP) and interleukin-8 (IL-8) levels during orthodontic treatment with self-ligating brackets versus conventional brackets. Patients and methods Forty patients were included in this study and distributed equally between two groups. One group received conventional edgewise brackets while the other group received DAMON self-ligating brackets. Periodontal parameters were recorded and biochemical and microbial analyses were conducted before bonding (baseline), and 14, 30, and 45 days after bonding. Paired t -test was performed to estimate the intergroup differences from the baseline at the various time points; unpaired t -test was used for intragroup comparisons. Results A significantly higher prevalence of gram-negative as well as gram-positive microorganisms was found in the group with conventional brackets than that with self-ligating brackets. Alkaline phosphatase (ALP) activity and interleukin-8 (IL-8) levels were significantly higher in the gingival crevicular fluid of the group with conventional brackets than that with self-ligating brackets. Conclusion The conventional bracket-ligature technique exhibited an increase in IL-8 levels, ALP activity, and microbial colonization compared with that of the self-ligature technique. Accordingly, self-ligating brackets are recommended in orthodontic patients to improve periodontal health and minimize damage outcomes of periodontal tissue interventions.