Longitudinal monitoring of pulpal and periapical health of adjacent natural teeth during the implant healing period: a prospective cohort study

BACKGROUND: The biological behavior of natural teeth adjacent to implant sites during surgery and healing remains incompletely understood. This longitudinal cohort study aimed to evaluate changes in pulpal sensibility and periapical status of natural teeth adjacent to an edentulous site planned for implant placement before surgery, during healing, and up to prosthetic rehabilitation. METHODS: Seventy-four teeth adjacent to implant sites in 31 patients were monitored. Clinical evaluations were performed preoperatively and postoperatively at week 1, month 1, and month 3, assessing palpation, percussion, cold testing, electric pulp testing (EPT), and Numerical Pain Rating Scores (NPRS). Radiographic images obtained preoperatively and at 3 months were analyzed for periapical changes. Data were analyzed using Cochran-Mantel-Haenszel, Friedman, and Wilcoxon signed-rank tests. Additionally, linear and logistic mixed-effects models were used to account for intra-patient clustering by treating patient as a random effect (α = 0.05). RESULTS: Percussion sensitivity was significantly higher at week 1 than preoperatively (P=.011), and at month 1 (12.2%) compared to month 3 (0%) (P=.046). No significant difference was found in EPT values between preoperative and week 1 (P>.05), but week 1 values were significantly higher than month 1 (P=.031). Preoperative NPRS scores were significantly lower than week 1, month 1, and month 3 (P<.05). One tooth (1.4%) required root canal treatment due to irreversible pulpitis at week 1. Sensitivity analyses using mixed-effects models confirmed the findings, with significant effects for NPRS (β=0.80, P<.001) and percussion sensitivity (OR = 5.23, P<.001) at the 1-week interval. CONCLUSIONS: Most adjacent teeth maintained pulpal health within 3 months after implant placement. While one case required endodontic treatment, the remaining postoperative changes were transient and consistent with postoperative healing rather than persistent pathological conditions. CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov (NCT06948734) on 29 April 2025.