The influence of different types of brackets and efficacy of two chlorhexidine mouthwashes on oral hygiene and the incidence of white spot lesions in adolescents during the orthodontic therapy.

BACKGROUND: To detect the effect of two different types of brackets (ceramic and stainless steel) and investigate the effectiveness of two chlorhexidine mouthwashes 0.2% (CHX) on oral hygiene status and incidence of white spot lesions (WSLs) in adolescents wearing fixed orthodontic appliance. SUBJECTS AND METHODS: One hundred and twenty subjects (aged 11 to 18 years, mean age 14.5 years) were divided into six equal groups according to brackets type and to different mouthwashes: Group 1: metal brackets and conventional CHX, Group 2: metal brackets and CHX with anti-discoloration system (CHX-ADS), Group 3: ceramic brackets and conventional CHX, Group 4: ceramic brackets and CHX-ADS, Group 5: metal brackets and water correction flavors mouthwash (placebo), Group 6: ceramic brackets and placebo. Four weeks after the placement of fixed orthodontic appliance the subjects were provided with three different mouthwashes for use during the next two weeks. Assessment was carried out according to oral hygiene index-simplified (OHI-S) and WSL index performed: prior to placement of the appliance (baseline), four weeks, six weeks, eighteen weeks, and thirty weeks after the placement. The data were then subjected to statistical analysis. RESULTS: Group 4 showed reduction in the OHI-S scores when compared to the Group 5 (in the 6th week), and Group 6 (in the 6th and 18th week), which was statistically significant, P<0.05. Group 4 showed decrease in the WSLs scores when compared to the Group 1 (in the 4th, 6th, 18th and 30th week), Group 5 (in the 18th and 30th week) and Group 6 (in the 6th, 18th and 30th week), which was statistically significant, P<0.05. CONCLUSION: The ceramic brackets and the usage of CHX-ADS resulted in better oral hygiene status and lower incidence of WSLs.

In Vitro Evaluation and Comparison of the Translucency of Two Different All-Ceramic Systems.

OBJECTIVES: The aim of this study was to evaluate and compare the translucency of two different all-ceramic systems using Vita Easyshade digital shade matching device in an in vitro model. MATERIALS AND METHODS: Translucency of lithium disilicate glass-ceramic (IPS e.max Press) and zirconia all-ceramic system (Ceramill ZI) were evaluated and compared. A total of 5 square-shaped specimens with 0.5 mm thickness were fabricated from each ceramic system in A1 shade according to Vitapan Classical shade tab. Specimens were then veneered and glazed with corresponding veneer ceramics recommended by each system manufacturer and the total thickness was set to 1.5 mm. Translucency was evaluated using VITA Easyshade in two stages: before and after veneering and glazing on black and white background. Translucency parameter (TP) was calculated. A one-way ANOVA and Bonferonni tests were used when appropriate (α=0.05). RESULTS: Lithium disilicate glass-ceramic was significantly more translucent than the zirconia system in both stages (P<0.05). Translucency of all specimens was significantly decreased after veneering and glazing in both all-ceramic systems (P<0.05). CONCLUSION: The translucency of two different dental ceramics was significantly influenced by both material and stages of preparation. Within the limitations of the experiment, these results can be valuable and help the clinician to make appropriate esthetic decisions.

Influence of Adhesives and Methods of Enamel Pretreatment on the Shear Bond Strength of Orthodontic Brackets.

AIM: The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). MATERIAL AND METHODS: The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B-37% phosphoric acid; Fuji Ortho LC, group C-self etching primer; Transbond XT, group D-37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. RESULTS: After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. CONCLUSION: The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer's recommendation is the "gold standard" for brackets bonding for fixed orthodontic appliances.