[The advances in the edgewise technique].

Investigation of shear-peel bond strength of orthodontic brackets on enamel after using Pro Seal.

AIM: The aim of this investigation was to ascertain whether the use of a fluoride-releasing, light-curing sealant (Pro Seal, Reliance Orthodontic Products, Itasca, IL, USA) results in differences in shear-peel bond strength when teeth are etched via the conventional acid-etching method and with self-etching primers (SEP), respectively. We also examined whether Pro Seal functions as a substitute for the bonding agents recommended by the manufacturers. MATERIAL AND METHODS: To carry out this study, we randomly allocated 300 extracted molars (ISO 11405) into twelve groups (n=25). The brackets used (Victory Series, Twin UBi 0T/0A .022, 3M Unitek, Seefeld, Germany) were bonded using the same layer thickness of adhesive. The teeth were then stored for 24 h in de-ionized water (37 degrees C) and subsequently thermocycled. The brackets were debonded using a universal testing machine with a crosshead speed of 0.5 mm/min. For statistical evaluation we used the one-way analysis of variance (ANOVA [alpha = 0.05]) and the post hoc Tukey test and Weibull analysis. RESULTS: We could establish that the use of Pro Seal does not have a negative influence on shear-peel bond strength. When the compomer Assure was used, Pro Seal even led to an increase in shear-peel bond strength, especially when it was applied using the bonding agent recommended by the manufacturer. The highest Weibull modulus (m) was found for the self-etching primer IDEAL 1 without using Pro Seal (m=6.5) and the lowest for First Step SEP when using Pro Seal (m=2.2). There were also clear differences in characteristic shear-peel bond strength (sigma(0)) within some of the groups investigated. CONCLUSIONS: Although the statistical evaluation showed no significant negative influence on the shear-peel bond strength either when Pro Seal was used in addition, or when that fluoride-releasing, light-curing sealant was substituted for the bonding agent recommended by the manufacturer, the Weibull analysis showed that the use of Pro Seal in combination with SEP resulted in bond strength values that were less reliably reproducible.