RESUMO
Background: This study assessed the stability of the outcomes after mandibular incisor extraction (MIE) using intercanine width and peer assessment rating (PAR) scores in orthodontic patients. Methods: PubMed, Cochrane Library, Science Direct, Google Scholar, Ovid, and SciELO were systematically searched without restrictions until August 2022. A risk of bias assessment was performed using Newcastle-Ottawa Scale (NOS). The Grading of Recommendations, Assessment, Development, and Evaluation tool was used to assess the quality of evidence. Random effects meta-analysis was performed using RevMan software. Results: Seven retrospective studies met the inclusion criteria and were included. Meta-analysis identified a statistically significant reduction in intercanine width with MIE after the retention period. The mean difference in post-retention changes concerning intercanine width (MD=0.14, 95% CI: -2.17-1.89; P<0.00001) was significantly higher in premolar extraction (PE) compared to incisor extraction and significantly less in non-extraction compared to incisor extraction (MD=0.72, 95% CI: -0.59-2.03; P<0.00001). Improvements in PAR scores from the start of treatment to the retention period indicated a high outcome standard (>70%) with MIE treatment, with no significant difference in the reduction percentage compared to premolar and non-extraction groups. Conclusion: With the existing retrospective studies of limited evidence, treatment outcomes with MIE were found to show good improvements in PAR scores. Some reduction in the intercanine width was evident after the retention period, which was observed even with the other two treatment modalities that were compared. Hence, with careful evaluation, MIE could be considered a valid treatment option.
RESUMO
AIM: To evaluate the effects of two preprocedural mouthrinses, hydrogen peroxide (H2O2) and povidone iodine (PI) on the surface characteristics and mechanical properties of nickel-titanium (NiTi) and stainless steel (SS) orthodontic archwires. MATERIALS AND METHODS: Five wire specimens were used, each (0.016" NiTi, 0.016" SS wires, 0.016 × 0.022" NiTi and 0.016 × 0.022" SS wires) specimen was cut into 30 mm lengths and immersed in 9% of artificial saliva and 91% of two preprocedural mouthrinse solutions: 1.5% hydrogen peroxide mouthwash, 0.2% povidone-iodine mouthwash, and distilled water (control group) for 90 minutes and incubated at 37°C. The wire specimens were then subjected to a three-point bending test for mechanical testing and viewed under a scanning electron microscope (SEM) to evaluate their surface characteristics. The collected data were analyzed using one-way analysis of variance (ANOVA) and Bonferroni post hoc test. RESULTS: The results showed a significant increase in the flexural modulus (E) of Nitinol wires in povidone-iodine gargle (p < 0.05) and a significant increase in the E of stainless steel wires in hydrogen peroxide mouthwash (p < 0.05). Analysis using SEM showed varying qualitative surface changes in the form of corrosion, voids, and ridges on the wires after exposure to both the mouthwashes. CONCLUSION: Though there were significant changes in the flexural modulus of archwires for both the mouthwashes, hydrogen peroxide did not show a significant difference in the E of wires at most of the deflection intervals when compared with the other two solutions, hence, could be used in orthodontic patients as an effective preprocedural mouthrinse. CLINICAL SIGNIFICANCE: Preprocedural mouthrinses can cause surface irregularities on the wires which in turn lead to an increase in friction at the bracket-wire interface, thereby disrupting effective tooth movement and extending the orthodontic treatment time.
