Timing of Single-Tooth Implant Rehabilitation and Periapical Inflammation Severity: A Retrospective Study Using the DAIS System

<b>Objective</b>: This retrospective study investigated the relationship between the timing of single-tooth implant-supported restorations-including the interval from tooth extraction and socket preservation to implant placement and final prosthetic restoration-and the severity of periapical inflammation, as classified by the Dental Apical Inflammation Score (DAIS). <b>Methods</b>: A total of 87 patients were included (DAIS 1: 8; DAIS 2: 14; DAIS 3: 1; DAIS 4: 64). Procedural intervals (extraction, socket preservation, implant placement, and prosthetic restoration) were analyzed alongside histological assessment of periapical inflammation. Clinical parameters such as tooth location, endodontic treatment status, patient age, and sex were examined using ANOVA, chi-square tests, and Pearson's correlation analysis. <b>Results</b>: An effective sample size of N = 86 (excluding the single DAIS 3 case) was included in the parametric analysis. No significant differences in procedural timing were found across DAIS groups for the intervals between extraction and implant placement (F(2, 83) = 0.338, <i>p</i> = 0.714) or restoration (F(2, 83) = 1.016, <i>p</i> = 0.367). Tukey's HSD post hoc analysis showed no pairwise group differences. Histological diagnosis was not significantly associated with DAIS (χ²(6) = 7.00, <i>p</i> = 0.321), though small subgroup sizes warrant interpretive caution. A significant association was identified between DAIS score and tooth location (χ²(3) = 11.79, <i>p</i> = 0.008). Patient age showed a weak but significant positive correlation with DAIS (r = 0.222, <i>p</i> = 0.039). No significant associations were found for endodontic status (χ²(3) = 2.54, <i>p</i> = 0.468) or sex (χ²(3) = 2.63, <i>p</i> = 0.452). Histological assessment revealed that most specimens represented radicular cysts with varying proportions of acute and chronic inflammatory infiltrates, consistent with the DAIS classification. <b>Conclusions</b>: Procedural timing did not significantly differ between DAIS groups. However, the observed associations with tooth location and patient age may warrant further investigation into their potential relevance for treatment planning. These findings suggest that implant timing may not need to be substantially modified according to DAIS severity alone, but that anatomical site and patient age should be considered during clinical decision-making.