Influence of Adhesives and Methods of Enamel Pretreatment on the Shear Bond Strength of Orthodontic Brackets

Svrha: Ovim se istraživanjem željelo ispitati kakav je utjecaj adheziva i postupaka pripreme cakline na smičnu snagu vezivanja (engl. shearbondstrenght – SBS) ortodontskih bravica. Korišteni adhezivi bili su smolom ojačani staklenoionomerni cement (engl. glassionomer cement – GIC; Fuji Ortho LC) i kompozitna smola (Transbond XT). Ispitanici i postupci: Eksperimentalni uzorak činilo je 80 ekstrahiranih prvih humanih pretkutnjaka, tj. premolara. Uzorak je bio podijeljen u četiri skupine, pa su metalne bravice lijepljene nakon različitih priprema cakline, a koristili smo se dvjema vrstama adheziva: u skupini A. 10-postotnom poliakrilnom kiselinom i Fuji Ortho LC-om; u skupini B: 37-postotnom ortofosfornom kiselinom i Fuji Ortho LC-om; u skupini C: samojetkajućim primerom (engl. self-etchingprimer – SEP) i Transbondom XT, u skupini D: 37-postotnom ortofosfornom kiselinom, primerom i Transbondom XT. Mjerena je SBS bravica. Nakon skidanja bravica određivao se indeks za procjenu preostaloga materijala na površini cakline (engl. AdhesiveRemnant Index – ARI). Rezultati: Nakon statističke analize podataka (ANOVA; Sheffeov posthoc test) rezultati su pokazali značajno manji SBS u skupini B u odnosu na skupine C (p = 0,031) i D (p = 0,026). Rezultati za ARI bili su slični u svim ispitivanim skupinama i nije bilo moguće utvrditi statistički značajnu razliku za procjenu preostaloga materijala na površini cakline (Hi-kvadrat test) između svih četiriju skupina. Zaključak: Možemo zaključiti da je uporaba kompozitnih smola, nakon odgovarajuće pripreme cakline prema uputama proizvođača, zlatni standard u vezivanju bravica u fiksnoj ortodonciji.Aim: The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). Material and Methods: The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B–37% phosphoric acid; Fuji Ortho LC, group C–self etching primer; Transbond XT, group D–37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. Results: After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. Conclusion: The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer’s recommendation is the “gold standard” for brackets bonding for fixed orthodontic appliances