Efeito de diferentes protocolos para remoção de biofilme na resistência ao cisalhamento de bráquetes ortodônticos

Abstract

The growing search for aesthetics in Dentistry and the demand of adults for orthodontic treatments to correct occlusion and smile increased the demand for the use of aesthetic orthodontic brackets, as they are more visually discreet. Although aesthetics is a great advantage and the main one for choosing this accessory, adherence to the enamel of ceramic aesthetic brackets is still a challenge and countless materials and techniques are launched on the market at all times. Various materials and techniques are available on the market today, and the selection of types of brackets and materials for bonding can be challenging in the face of so much diversity. Additionally, the materials are not the only ones responsible for the successes or failures of the collages, and the way the technique is performed is also extremely important. In this sense, cleaning the enamel surface before gluing is a prominent factor. Very little attention has been paid to a relatively simple but important question: What is the best protocol for preparing the enamel surface and removing dental biofilm and other substances that can improve the adhesion of orthodontic brackets to dental surfaces? Based on this, study was designed to evaluate the effect of different protocols for removing biofilm from the surface of bovine tooth enamel on the bond strength (BS) of ceramic and metallic brackets. Enamel bovine discs were randomly divided into 12 groups (n=10) according to the combination of the following factors: type of orthodontic bracket (ceramic or metallic); type of adhesive (Transbond XT or SingleBond + Z100), and enamel cleaning protocol (no-cleaning – control; cleaning with Clinpro Prophy Paste, or cleaning with prophylactic paste without fluoride (Villevie). All enamel discs were submitted to standardized biofilm accumulation (3 days under intermittent sucrose exposure). Subsequently, the cleaning protocol was performed for 10 seconds with a rotatory brush (except for the control group). Orthodontic brackets were bonded to enamel discs following manufactures’ instructions. All specimens were stored in distilled water (7 days) before the BS test. The debonded XT brackets and enamel surfaces of each sample were also assessed to determine the adhesive remnant index (ARI) for each subgroup. Higher BS was found for metallic brackets (p<0.001). No differences among cleaning protocols were found (p>0.05). Higher BS was found when metallic brackets were bonded to enamel using Transbond XT without biofilm removal (p<0.001). Metallic orthodontic brackets and Transbond XT showed lower ARI scores compared to ceramic brackets and Z100 adhesive (p < 0.001). In conclusion, the bonding of orthodontic brackets is not affected by the cleaning protocol and the type of adhesive technique. Metallic brackets showed higher bond strength to enamel than ceramic brackets.