# Association between smoking and the risk of dental implant failure in Korean adults: a nationwide cohort study

## TL;DR

Smoking increases the risk of dental implant failure in Korean adults, with current smokers facing the highest risk.

## Contribution

This study identifies a dose-dependent relationship between smoking and dental implant failure in a nationwide Korean cohort.

## Key findings

- Current smokers had a significantly higher risk of dental implant failure compared to non-smokers.
- A dose–response relationship was observed for smoking intensity, duration, and cumulative exposure.
- Ex-smokers showed a non-significant increase in implant failure risk.

## Abstract

We evaluated the associations of smoking status, intensity, duration, and cumulative exposure with the risk of dental implant failure in Korean adults.

This retrospective cohort study utilized the National Health Insurance Service–Health Screening Cohort (2016–2019). Overall, 23,573 individuals who had completed the dental implant process were included. Smoking status was categorized as non-smoker, ex-smoker, or current smoker. Smoking intensity, duration, and cumulative exposure were classified using standardized thresholds (>10 cigarettes per day, >10 years, and >10 pack-years). Implant failure was defined as reimplantation or removal. Cox proportional hazards models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for demographic, clinical, and behavioral covariates.

During follow-up, 605 implant failures occurred: 344 in non-smokers, 182 in ex-smokers, and 79 in current smokers. The corresponding incidence rates per 1,000 person-years were 11.56, 16.54, and 22.33, respectively. Current smoking was significantly associated with higher implant failure risk (adjusted HR, 1.59; 95% CI, 1.20 to 2.09), while ex-smokers displayed a non-significant increase (adjusted HR, 1.16; 95% CI, 0.94 to 1.45). A dose–response relationship was observed: smoking more than 10 cigarettes per day, smoking for more than 10 years, or exceeding 10 pack-years was associated with significantly increased risk.

Smoking is a significant, dose–dependent risk factor for dental implant failure in Korean adults. Current smokers have the highest risk; smoking cessation may reduce adverse outcomes. These findings emphasize the importance of detailed smoking assessments and cessation counseling in implant care and public health strategies.