Effectiveness of Restoration Strategies for Posterior Missing Teeth With Dental Implants: A Retrospective Study

This study aimed to assess the effectiveness of a treatment strategy involving only implant restoration of the first molars (M1s) in cases where both M1s and second molars (M2s) lost.

A retrospective study design compared two groups: one underwent simultaneous implant restoration of both M1s and M2s (Group 1), while the other underwent restoration of only M1s (Group 2). Statistical models were used to evaluate implant survival, complication-free survival rates, cumulative treatment costs, peri-implant conditions, and patient-reported outcomes (PROMs).

This study included 247 patients, with 283 partially edentulous posterior regions. Group 1 consisted of 195 areas, and Group 2 comprised 88 regions. The analysis revealed no significant differences between the two groups in implant survival rates (hazard ratio [HR] = 1.66, 95% confidence interval [CI]: 0.29-9.50, p = 0.567) or complication-free survival rates (HR = 1.21, 95% CI: 0.49-3.04, p = 0.678). Group 2 showed 1.7 times lower cumulative costs (β = -14.40, p < 0.001) and had no peri-implantitis cases compared to a 16.2% incidence in Group 1 over 3 years (p = 0.043). Radiological assessment indicated that Group 2 was a protective factor against more than 0.5 mm marginal bone loss (β = 0.34, p = 0.012). PROMs demonstrated no significant differences in chewing ability for soft and hard foods between Group 1 and Group 2. Group 2 reported lower post-surgery pain scores, while both groups had similar discomfort and food impaction rates.

Considering the limitations of this study, implant restoration with only M1s may be an effective and cost-efficient treatment option for patients who have lost both M1s and M2s.