Variables affecting tooth survival and changes in probing depth: a long-term follow-up of periodontitis patients

AimTo retrospectively assess tooth-survival rate and its association with patient and oral variables in periodontal office patients, followed up to 18years. Material and MethodsPatients in a private periodontal office whose files included initial examination (T-0), reevaluation (T-Re) and 10years after T-0 (T-F) chartings, and received periodontal therapy and supportive periodontal therapy (SPT) after T-Re were included. General health, plaque scores (PI), probing depth (PPD), bleeding on probing (BOP) at six points/tooth, tooth extractions, and SPT visits were extracted from patient files at T-0, T-Re, and T-F. Descriptive statistics and Cox regression analysis were performed. ResultsFifty patients (mean 264 teeth/patient, 1301 teeth) fulfilled inclusion criteria. About 20 and 129 teeth respectively were extracted before/after T-Re, 96 of them for periodontal causes. PPD>7mm at T-Re (HR=17.7, 95%CI 8.6, 36.6), age above 60years (HR=3.3, 95%CI 1.5, 7.2), multi-rooted teeth (HR=1.9, 95%CI 1.2, 3.1) and SPT<3 times/year (HR=1.8, 95%CI 1.1, 2.9), were the best prognostic factors for tooth loss during follow-up. (p<0.05, Cox regression analysis). A continuous, statistically significant reduction was observed in mean PPD among teeth that survived follow-up [4.3 +/- 1.8mm, 3.5 +/- 1.4mm, 3.2 +/- 1.3mm, at T-0, T-Re, T-F, respectively. (p<0.001, Repeated-measures test)]. ConclusionRegular SPT was associated with low tooth-loss rates and continuous reductions in probing depth. PPD after initial therapy, age above 60, multi-rooted teeth and infrequent SPT were strong negative prognostic factors for long-term tooth survival among periodontal patients.