American Board of Orthodontics (ABO) Practice Exam 2025 - Free Orthodontics Practice Questions and Study Guide

The correct answer focuses on the smooth surfaces of teeth, which are particularly susceptible to caries in patients who abuse opioids. This phenomenon can be attributed to several factors associated with opioid use.

Patients who abuse opioids often experience dry mouth, or xerostomia, as a side effect. Saliva plays a critical role in neutralizing acids produced by bacteria in the mouth and helps to wash away food particles and plaque. A reduction in saliva production significantly increases the risk of decay, especially on smooth surfaces where plaque accumulation can be more difficult to remove through normal oral hygiene practices like brushing.

Additionally, individuals with opioid addiction may have less motivation to maintain proper oral hygiene, leading to increased plaque build-up on the smooth surfaces of teeth. This accumulation of plaque can quickly lead to carious lesions in these areas, making smooth surfaces a predominant site for caries in this patient population.

To summarize, the combination of dry mouth, decreased oral hygiene practices, and the natural caries susceptibility of smooth surfaces in the context of opioid abuse directly contributes to the higher occurrence of caries in these areas.