Longitudinal comparison of peri-implant clinical and radiographic parameters between e-cigarette users and conventional cigarette smokers.

BACKGROUND: Conventional cigarette smoking is associated with peri-implant disease, but longitudinal evidence for electronic cigarette (e-cigarette) exposure is limited. We compared 12-month peri-implant clinical and radiographic trajectories between e-cigarette users and conventional cigarette smokers and assessed unequal current exposure duration. METHODS: This single-center retrospective study included 328 patients with 452 implants (e-cigarette [EC] group, 152 patients/206 implants; conventional cigarette [CS] group, 176/246). Modified plaque index (mPLI), probing depth (PD), modified sulcus bleeding index (mSBI), bleeding on probing (BOP), mucosal recession (MR), keratinized mucosa width (KMW), and marginal bone level (MBL) were recorded at loading, 6 months, and 12 months while implants remained in situ. Patient-clustered generalized estimating equations (GEE) assessed group, time, and group-by-time effects. PD and change in MBL (ΔMBL) were prioritized. A post hoc sensitivity model additionally adjusted for current exposure duration; product-specific intensity variables were examined within groups. RESULTS: Continuous outcomes were available for 452, 448, and 440 implants at loading, 6 months, and 12 months, respectively; all 12 removals were entered into failure analyses. Current exposure duration was shorter among e-cigarette users (median, 3.0 vs. 12.0 years). At 12 months, mean PD was 3.18 versus 3.72 mm, and mean ΔMBL was 0.68 versus 1.01 mm. After duration adjustment, conventional cigarette exposure remained associated with greater PD (difference, 0.42 mm; 95% confidence interval [CI], 0.25-0.59; interaction P = 0.003) and ΔMBL (0.26 mm; 95% CI, 0.15-0.37; interaction P = 0.015). The crude mucositis association attenuated after parsimonious adjustment (odds ratio [OR], 1.72; 95% CI, 1.02-2.90; P = 0.043; adjusted odds ratio [aOR], 1.64; 95% CI, 0.98-2.75; P = 0.060). Peri-implantitis and post-loading failure comparisons were not statistically significant. CONCLUSIONS: Conventional cigarette exposure was associated with larger 12-month peri-implant changes than e-cigarette exposure. Unequal exposure duration, unmeasured previous smoking, self-reported exposure, device heterogeneity, informative implant removal, and absence of a never-smoker group limit causal and absolute-risk interpretation.