This study explores whether clear aligners used in orthodontic treatment release very small plastic particles, known as microplastics, into the mouth. While aligners are made from safe medical-grade plastics, everyday use such as chewing, temperature changes, and saliva exposure may cause the material to gradually wear down. We will collect saliva samples from patients before starting aligner treatment and after several months of use to see if these particles can be detected. Advanced laboratory techniques will be used to identify and analyze any plastic particles present.

Our preliminary findings suggest that small plastic-related compounds may already be present in patients wearing aligners, but this study aims to confirm and better understand this in real clinical conditions. The goal is to determine how much exposure may occur and what types of materials are involved. This information will help improve the safety of orthodontic materials and guide future recommendations for both patients and providers.

In the current study, we will recruit individuals using addictive drugs (cocaine, cannabis, opioids, or methamphetamine) and non-drug use control individuals. The study participants will fill out questionnaires, consent, and donate samples (urine, saliva, nasal swab, and blood). These samples will be used to study the causes of unhealthy conditions during drug uses. Our goal is to prevent or treat the drug-associated unhealthy conditions (i.e., anxiety, memory impairment).

This study will examine how marijuana use can affect oral bacteria and brain health in people with HIV and without HIV. Early studies show that marijuana users have more oral bacteria than non-marijuana users. The increase in bacteria is believed to affect brain health. Participation in the study will be one visit. The visit will take approximately 120 minutes.