Survival rate of teeth adjacent and nonadjacent to dental implants: A retrospective cohort study

The aim of this retrospective study was to investigate the risk of tooth loss for teeth adjacent and nonadjacent to dental implants.

A total of 787 patients with an average follow-up of 57.1 months were examined to define the tooth loss, cumulative survival rate, and odds ratio (OR) for teeth adjacent versus nonadjacent to implants. A multivariate logistic regression was employed to assess the association between dental history and various recorded etiologies of tooth loss among teeth adjacent to implants.

The incidence of tooth loss for teeth adjacent to implants was 8.1% at the tooth level and 15.1% at the patient level, while 0.7% and 9.5% at the tooth and patientlevel for teeth nonadjacent to implants. The 10-year cumulative survival rate for teeth adjacent to implants was 89.2%, and the primary etiology of tooth loss was root fracture (45.2%). The risk of tooth loss among teeth adjacent versus nonadjacent to implants was significantly higher (OR 13.15). Among teeth adjacent to implants, root canal-treated teeth had a significantly higher risk of tooth loss due to root fracture (OR 7.72), a history of existing restoration significantly increased the risk of tooth loss due to caries (OR 3.05), and a history of periodontitis significantly increased the risk of tooth loss due to periodontitis (OR 38.24).

The present study demonstrated that after patients received dental implant treatment, teeth adjacent to implants showed a 13.2-fold higher risk of tooth loss compared to teeth nonadjacent to implants, with the primary etiology being root fracture.