Scanning electron microscopic examination of enamel surface after fixed orthodontic treatment: In-vivo study

Abstract

Introduction. Therapy with fixed orthodontic appliances starts with bracket bonding and ends with debonding of brackets, leaving enamel surface varied. Objective. The aim of this pilot study was to examine enamel surface before and after debonding of orthodontic brackets by the use of scanning electron microscopy (SEM). Methods. Epoxy replicas of four patients' premolars indicated for therapy with fixed orthodontic appliances were made and brackets were bonded to their teeth with a different adhesives (Enlight, No-mix, Fuji Ortho LC and Heliosit Orthodontic) (n=4). Two months later, brackets on premolars were debonded and amounts of adhesive left on the tooth surfaces and the bracket bases were evaluated with the adhesive remnant index (ARI). After resin removal, epoxy replicas were made and the surface of premolars was evaluated with the enamel surface index (ESI). All replicas of premolars (n=32) were prepared for SEM examination and compared under different magnifications. Tooth damage was estimated based on correlation between ARItooth and ESI. Results. Pearson's χ2 test showed no significant differences between ARItooth and ARIbracket of four materials used. Nonparametric correlations showed significant differences between ARItooth and ARIbracket, ESI and ARItooth, and between ESI and ARIbracket. Increasing of ARItooth is followed with the descent of ARIbracket and the ascent of ESI. Multivariate regression analysis showed a significant correlation between ESI and ARItooth. Conclusion. Most bond failures took place at enamel-adhesive interface. ARItooth was a predictor to enamel surface damage. The type of material did not affect enamel surface damage.

Uvod. Terapija fiksnim ortodontskim aparatom počinje postavkom bravica, a završava se njihovim uklanjanjem na kraju terapije, nakon čega je površina gleđi izmenjena. Cilj rada. Cilj ove pilot- studije bio je da se ispita površina gleđi pre i posle skidanja ortodontskih bravica primenom skening- elektronske mikroskopije (SEM). Metode rada. Izrađene su replike premolara šest pacijenata kod kojih je indikovana terapija fiksnim ortodontskim aparatom i svakom od njih zalepljene su bravice različitim adhezivom (Enlight, No-mix, Fuji Ortho LC i Heliosit Orthodontic). Dva meseca kasnije bravice na premolarima su uklonjene, a količina preostalog adheziva na zubu i bravici određena je indeksom zaostalog adheziva (engl. adhesive remnant index - ARI). Posle uklanjanja adheziva načinjene su replike zuba i površina premolara je procenjena pomoću indeksa površine gleđi (engl. enamel surface index - ESI). Sve 32 replike premolara pripremljene su za ispitivanje primenom SEM i upoređivane pri različitom uveličanju. Oštećenja zuba su procenjivana korelacijom vrednosti ARI zuba i ESI. Rezultati. Pirsonov χ2-test nije pokazao značajne razlike između vrednosti ARI zuba i ARI bravica u odnosu na četiri korišćena materijala. Neparametarske korelacije ukazale su na značajne razlike između vrednosti ARI zuba i ARI bravica, ESI i ARI zuba i ESI i ARI bravica. Povećanje vrednosti ARI zuba bilo je praćeno smanjenjem vrednosti ARI bravica i povećanjem ESI. Multivarijantna regresiona analiza pokazala je značajnu povezanost ESI i ARI zuba. Zaključak. Prekid veze najčešće se javljao na spoju između gleđi i adheziva. ARI zuba se pokazao kao prediktor oštećenja gleđi. Vrsta materijala nije uticala na oštećenja površine gleđi.