The influence of coronal restoration type on the survival of endodontically treated teeth.

The aim of this study is to investigate the association between coronal restoration type and survival of endodontically treated teeth. A review was performed of treatment records of patients who had endodontic treatment performed in the Department of Restorative Dentistry, University Dental School & Hospital, Cork, Ireland during the period 1993-96. Demographic and dental factors such as age, gender, tooth type, coronal restoration type, and tooth status recorded at a review appointment were recorded. Tooth status at review was defined as 'tooth present' or 'tooth absent' based on the presence or absence of the endodontically treated tooth recorded in the treatment records at a review appointment held a minimum of one year following obturation of the root canal system. Of 176 teeth (166 patients) treated, survival of endodontically treated teeth was significantly more likely where restored with cast restorations (91.7%), amalgam restorations (86.5%), or composite restorations (83.0%), than teeth restored with temporary restorations (34.5%) (p<0.0001) (mean follow-up time 38 months, range 12-60 months). Survival of endodontically treated teeth was found to be associated with permanent coronal restorations. Loss of endodontically treated teeth occurred more often with those restored with temporary restorations (34.5%) than other restoration types (p<0.05).