The aim of this study was to assess the bond strength of a resin cement to intraradicular dentin varying the light-curing unit and the moment at which the light was applied. Post spaces of endodontically treated canines were prepared. The roots were distributed into 6 groups (n=10) according to the light-curing unit and the moment of light exposure: I) Quartz tungsten halogen-600 mW/cm² (QTH) + immediate light activation (t0); II) QTH + light activation after 10 min (t10); III) Light-emitting diodes (LED)-800 mW/cm² (LED-800)+ t0; IV) LED-800 + t10; V) LED-1,500 mW/cm² (LED-1500)+ t0; VI) LED-1500 + t10. After post cementation, slices from coronal, middle and apical post/root regions were submitted to the push-out test and failure evaluation. It was verified that LED-800 (4.40 ± 3.00 MPa) and LED-1500 (4.67 ± 3.04 MPa) provided bond strength statistically superior to QTH (3.13 ± 1.76 MPa) (p<0.05), and did not differ from each other (p>0.05). There was no significant difference between t0 and t10 (p>0.05). Coronal post/root region (4.75 ± 3.10 MPa) presented significantly higher bond strength than the apical (3.32 ± 2.30 MPa) (p<0.05) and middle regions (4.14 ± 2.99 MPa) showed intermediate values. Adhesive failures were predominant when using QTH. Adhesive and mixed failures occurred more frequently in the apical region. Higher adhesion of the resin cement to intraradicular dentin was observed in the coronal region with LED light-activation, regardless of the moment of light exposure.

Traumatic injuries are usually the result of impacts whose aggressive strength exceeds the resistance found in bone, muscle and tooth tissues. With the advent of the etching technique and considering the improvement of composite resins, simpler and more conservative alternatives are indicated in the aesthetic and functional rehabilitation of fractured anterior teeth. Case report and objective: This study aimed to report the treatment of a 13 year-old patient that fractured his central incisor due to a trauma. After clinical and radiographic examination, an oblique crown fracture with extensive involvement of the incisal angle, without pulp exposure or injury to the biological space of the left maxillary central incisor (tooth #21) was observed. Because the fractured tooth fragment was lost, it was not possible to process a fragment bonding. Thus, it was proposed to treat the tooth through direct technique restoration with composite resin. Conclusion: It can be concluded that the aesthetic and functional rehabilitation with direct composite resin is a viable option for the conservative treatment of fractured anterior teeth.