ABSTRACT
Bond failure after rebonding for newly placed brackets can be reduced by appropriate enamel surface treatment. This in vitro study investigated the effect of two enamel surface treatments on the bond strength of metallic brackets in the rebonding process. After debonding the brackets and removing the residual adhesive on the enamel surface of 50 upper premolar teeth, the teeth were divided into two equal groups. In the first group, the enamel surface was etched with phosphoric acid 37 per cent, and in the second group, the teeth were sandblasted prior to acid etching. After bonding of the new brackets, the shear bond strength (SBS), probability of bond failures, and adhesive remnant index (ARI) were determined and compared with the t-test, Weibull analysis, and chi-square test. Mean SBS in both groups did not differ significantly (P = 0.081). Most bond failures occurred with ARI scores of 2 and 3, and the difference between the two groups was statistically significant (P < 0.001). Weibull analysis showed that for a given stress, the probability of failure differed between groups. Enamel surface preparation with sandblasting prior to acid etching did not significantly improve SBS in bracket rebonding and left more residual adhesive remnants on the enamel surface.
Subject(s)
Acid Etching, Dental/methods , Dental Bonding/methods , Dental Enamel , Orthodontic Brackets , Shear Strength , Adhesiveness/drug effects , Adolescent , Adult , Bicuspid , Chi-Square Distribution , Dental Bonding/standards , Dental Enamel/drug effects , Dental Stress Analysis/methods , Hardness Tests , Humans , Phosphoric Acids/chemistry , Resin Cements/chemistry , Retreatment/methods , Young AdultABSTRACT
To provide quantitative data about the prevalence of malocclusions in the Shiraz orthodontic population, we studied the records of 700 patients (391 girls and 309 boys) aged 6-14 years attending the undergraduate Department of Orthodontics at Shiraz University of Medical Sciences. The prevalence of Angle class I, II and III malocclusion of first molars was 52.0%, 32.6% and 12.3% respectively. Skeletal class I, II and III malocclusion was found in 18.0%, 70.0% and 12.0% respectively. There were no significant differences between the sexes in the prevalence of different types of skeletal malocclusion. Children with class III were significantly younger (mean age 8.9 years) than those with class I (9.6 years) or class II (9.7 years) malocclusions. Orthodontics students need more education and training in the management of class II malocclusion to improve the overall quality of care for patients.
ABSTRACT
To provide quantitative data about the prevalence of malocclusions in the Shiraz orthodontic population, we studied the records of 700 patients [391 girls and 309 boys] aged 6-14 years attending the undergraduate Department of Orthodontics at Shiraz University of Medical Sciences. The prevalence of Angle class I, II and III malocclusion of first molars was 52.0%, 32.6% and 12.3% respectively. Skeletal class I, II and III malocclusion was found in 18.0%, 70.0% and 12.0% respectively. There were no significant differences between the sexes in the prevalence of different types of skeletal malocclusion. Children with class III were significantly younger [mean age 8.9 years] than those with class I [9.6 years] or class II [9.7 years] malocclusions. Orthodontics students need more education and training in the management of class II malocclusion to improve the overall quality of care for patients
