7-Year clinical evaluation of direct composite restorations in cracked teeth

Objectives: To investigate the long-term clinical effectiveness of treating painful cracked teeth with a direct bonded composite resin restoration. Methods: 41 patients attended a dental practice with a painful posterior tooth suffering from the ‘cracked tooth syndrome'. After the diagnosis the amalgam-restoration was removed, a 3-step etch-and-rinse adhesive system (Clearfil SA primer-PhotoBond) was applied, followed by a direct composite resin (Clearfil PhotoPosterior - Kuraray). At random, 20 teeth were restored without cusp-reduction, 21 teeth with cusp-reduction and composite-coverage. Teeth were monitored over a period up to 7 years. On the last check-up, teeth were evaluated on the presence of sensitivity. A Kaplan Meyer survival analysis with Log-rank test was done on the data. Results: After 7 years, 39 teeth could be evaluated, 2 patients had left the practice. 6 teeth, all without cuspal coverage, showed major failures requiring further treatment: 3 teeth needed endodontic treatments due to irreversible pulpitis. Two of those teeth were extracted due to vertical fracture after 2 and 6 years respectively. Three restorations needed repair due to marginal ridge fracture(1), erosive wear next to the outline(1) and secondary caries(1). 37 (95%) teeth remained vital after 7 years. 2 patients experienced incidentally sensitivity for cold from the treated tooth. Mean annual failure rate after 7 years of the group without cuspal coverage was 6%, of the group with cuspal coverage 0% (p=0.009) Conclusions: A direct bonded composite resin restoration can be a successful treatment for a vital tooth with the cracked tooth syndrome. Cuspal coverage of the compromised cusp increases the success rate of the treatment.