Comparative evaluation of shear bond strength of different orthodontic brackets bonded with two different colour change orthodontic adhesives on fluorosed teeth.

The success of orthodontictreatment relies on the bonding of brackets to enamel. However, bracket bondingfailure is a common issue, especially when bonding on fluorosed enamel, whichis more porous and hypomineralized. Fluorosed enamel contains acid-resistantcrystals and a higher protein content, compromising bonding. Alternativetreatments are proposed to improve bracket retention, such as intraoral sandblastingto increase surface roughness or deproteinization using sodium hypochlorite(NaOCl) to remove organic elements. The conversion of resin cement into apolymer is also important for successful bonding.

AIM AND OBJECTIVESAIM

The aim of thisstudy is to compare the shear bond strength of self-ligating brackets (metal& ceramic) and conventional bracket (metal & ceramic) which are bondedon fluorosed teeth.

OBJECTIVESTo investigate the effect of fluorosis on shear bond strength,etching time, adhesive remnant index score (ARI) when bonding differentorthodontic brackets on fluorosed enamel.

METHODOLOGY

·     The sample consisted of 44human fluorosed extracted for orthodontic purposes. Teeth were stored informalin until bonding procedures.

·     The sample size (n = 44) wasestimated with power analysis to provide statistical significance alpha = 0.05at an 80% power.

·     44 fluorosed teeth were dividedinto 4 groups of 11 each and bonded with different brackets.

·     Before bonding, the facialsurfaces of the teeth were cleaned with a mixture of water and pumice.

·     The teeth were rinsedthoroughly with water and dried with compressed air.

·     Each tooth is etched with 37%phosphoric acid gel for 30 seconds. Then, all teeth will be rinsed withwater/spray combination for 30 seconds and dried.

·     Polymerization of the bondingagent will be performed with a conventional LED curing light for 15 seconds forceramic brackets and 20 seconds for metal brackets.

·     Before determining the shearbond strength  and subsequent debonding,bonded teeth are stored in distilled water for 24 hours.

·     The shear bond strength testswill be performed at a crosshead speed of 1 mm/min during debonding. Theshearing debonding force is directed occluso-gingivally and recorded in MPa.Bond strengths were compared by ANOVA test.

·     A stereomicroscope at amagnification of 20x will be used to assess the amount of adhesive remaining onthe teeth and the brackets after debonding and will be scored according to theadhesive remnant index (ARI).

·     If deemed, necessary changeswill be made in the best interest of the study.