FACTORS RELATED TO LOSS OF ROOT-CANAL FILLED TEETH

Objectives: This case-control study characterized factors related to l oss of root canal filled (RCF) teeth among members of the Kaiser Perma nents Dental Care Program, a dental health maintenance organization ba sed in Portland, Oregon. Methods: Individuals were identified who were enrolled continuously from January 1, 1987, through December 31, 1994 , underwent initial root canal therapy on a permanent tooth (excluding third molars) in 1987 or 1988, had a clinical examination within two years after endodontic access, and were at least 21 years old at acces s. Patients who lost the RCF tooth by December 31, 1994, were defined as cases (n = 96); those who did not were defined as controls (n = 120 ). Computerized data, dental radiographs, and chart entries were revie wed to ascertain variables of interest, and multivariable logistic reg ression was used to describe differences between the groups. Results: RCF teeth of cases had fewer proximal contacts at access than RCF teet h of controls (odds ratio = 2.7; 95% Cl = 1.4, 5.1). Cases were older (odds ratio = 1.4; 95% Cl = 1.1, 1.9 per 10-year increase) and more li kely to have had a facial injury than controls (odds ratio = 3.6; 95% Cl = 1.2, 10.5). Cases also had more missing teeth (odds ratio = 1.5; 95% Cl = 1.0, 2.1) and more plaque (odds ratio = 1.7; 95% Cl = 1.0, 2. 6). Conclusions: Conditions evident during treatment planning may help dentists assess patients' chances of losing an RCF tooth.