RESUMEN
INTRODUCTION: The effect of Khat and Shammah habits, with the parafunctional jaw activities that accompany them, on the integrity of the natural dentition, dental restorations, and prostheses has not yet been investigated. This study is the first attempt to identify the patterns of restorative failure among Khat chewers and Shammah users in Jazan City, Kingdom of Saudi Arabia. MATERIALS AND METHODS: A cross-sectional study was conducted in 294 recruits among dental clinics in Jazan City, Kingdom of Saudi Arabia, from October 1, 2015, to April 30, 2016. The patients were surveyed and examined to identify the type of restorations/prosthesis they had and their failures. Bivariate analysis was conducted to investigate the association of the restorative failure with the demographic variables. General linear model was performed to investigate the association between restorations/prostheses failure and Khat/Shammah use with the controlling factors of age and gender as independent variables. RESULTS: Khat/Shammah use was statistically significantly associated with restorative failure (p < 0.05) relative to amalgam, composite, crowns, fixed partial dentures, removable partial dentures, and complete dentures. In addition, a significant association of restorative failure was observed with gender, education, and brushing. CONCLUSION: Consumption of Khat/Shammah may be attributed as one of the reasons associated with restorative failure among the Saudi population.