Fracture Resistance of Incisal Fragments Following Reattachment With Different Techniques in Simulated Crown Fractures

The aim of the present study was to evaluate and compare the effect of acid-etching and Er, Cr:YSGG laser treatment before the reattachment of incisal fragments in coronal fractures of permanent incisor teeth.
Sixty-six sound human maxillary incisors were randomly divided into 3 groups (n=22). Teeth were embedded in self-cure acrylic resins by leaving one-third of the crowns out, and uncomplicated crown fractures were obtained using an Instron testing device. The fragments were reattached using 3 different procedures and a hybrid resin composite (Z250): Group I: Acid etching Prime & Bond NT; Group II: Er,Cr:YSGG Prime & Bond NT; Group III: Er,Cr:YSGG Acid etching Prime & Bond NT. The percentages of shear bond strengths were determined by comparing fracture strengths of sound and reattached teeth for 3 groups. All data were analyzed statistically with Kruskal-Wallis H test.
Mean fracture strengths of the reattached fragments were between 51.02% and 62.93% of that of the sound teeth in all groups. Group I had significantly higher percentages of shear bond strength values (P 0.05) was found between group II and group III.
The findings of the present study show that Er,Cr:YSGG laser irradiation prior to the reattachment of incisal fragments has a negative effect on fracture strength.