Comparison of Twin Block appliance and Herbst appliance in the treatment of Class II malocclusion among children: a meta-analysis.

BACKGROUND: Our meta-analysis aimed to evaluate the efficacy of applying Herbst and Twin Block appliances in the treatment of Class II malocclusion among children. METHODS: Databases, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), China VIP Database (VIP), and Wanfang were thoroughly searched from inception to August 9, 2023. The outcomes included skeletal, dental, and soft tissue changes. The weighted mean difference (WMD) was used as the effect indicator, and the effect size was expressed with a 95% confidence interval (CI). The heterogeneity of each outcome effect size was tested, and the heterogeneity statistic I2 ≥ 50% was analyzed by the random-effect model, otherwise, the fixed-effect model was conducted. Sensitivity analysis was performed. RESULTS: A total of 12 studies involving 574 patients were included in this meta-analysis. Herbst appliance had a statistically significant increase in mandibular body length (WMD: 1.44, 95% CI: 0.93 to 1.96, P < 0.001) compared with the Twin Block appliance. More increases in angle and distance of L1 to mandibular plane (MP) were found in the Herbst appliance compared with the Twin Block appliance. Significant and greater improvements in molar relationship (WMD: 0.79, 95% CI: 0.28 to 1.29, P = 0.002), posterior facial height (WMD: -1.23, 95% CI: -2.08 to -0.38, P = 0.005), convexity angle (WMD: -1.89, 95% CI: -3.12 to -0.66, P = 0.003), and Sella-Nasion plane angle (U1 to SN) (WMD: 3.34, 95% CI: 2.25 to 4.43, P < 0.001) were achieved in the Twin Block appliance. Herbst and Twin Block appliances produced similar effects in the skeletal and dentoalveolar changes including Sella-Nasion-point A (SNA), Sella-Nasion-point B, point A-Nasion-point B (ANB), overjet, and overbite. CONCLUSION: As the findings revealed both Herbst and Twin Block appliances contributed successfully to the correction of Class II malocclusion. Compared with the Twin Block appliance, the Herbst appliance may have more advantages in mandibular bone movement. Twin Block therapy resulted in more improvement in the aesthetics of the face.

[Effect of OHOLV on the remineralization of early enamel caries].

OBJECTIVE: To observe the effect of OHOLV on the remineralization of early enamel caries. METHODS: Fifty bovine teeth with artificial early caries were divided into five groups randomly and treated with OHOLV, casein phosphopeptide amorphous calcium phosphate (CPP-ACP), NaF, OHOLV+NaF and distilled and deionized water (DDW) respectively. Then the teeth were subjected to the pH-cycling. The surface microhardness (SMH) of enamel before demineralization and after remineralization were measured by microhardness detector and the histomorphologic changes of the enamel surface were compared by scanning election microscope (SEM). RESULTS: The SMH of all the experimental groups increased significantly after remineralization (P < 0.001). The SMH of the OHOLV group was lower than that of NaF group (P < 0.001), while there was no significant difference between the OHOLV group and the CPP-ACP group (P > 0.05). After remineralization, a large amount of comparatively large mineral particles deposited on the surface of the enamel treated with OHOLV. CONCLUSION: OHOLV can promote the remineralization of the early enamel caries.