Intraoral quantitative time-lapse measurements of tooth wear, displacement & recession

Objectives: This study is important because it provides the first quantitative approach for clinically diagnosing the rate of tooth wear, tooth movement, and buccal gingival recession. These patient-specific measurements can guide clinical decisions regarding prevention and intervention. The current literature suggests that teeth lose enamel at a rate of 100 um a year and that tooth movement and gum loss are age-related changes. Methods: Data were collected over a 29-month period in 51 patients (20 male,31 female; 20-60 yo) with clinically observable tooth wear, crowding, and mucogingival defects. An intraoral scanner (Element, Itero, San Jose, CA) with newly developed time-lapse software captured digital 3D images of all teeth in both dental arches at ~ 6-month intervals. Scanner resolution was 50um. Scanning time was <10 minutes. Data were collated in 4 magnitudes for wear, displacement, and recession: 100-150 um (mild), 150-200 um (moderate), 200-250 um (advanced), >250 um (excessive). The software mapped quantitative changes in surface wear with data-graphic color by value over two time points. Patients were scored if at least one tooth in either arch showed change. Results: 31 patients (61%) showed at least one tooth that exceeded 100 um of wear. Moderate to excessive tooth wear occurred most often in the 30 yo cohort (n=12, 39%) compared to the 20 yo (n=4,13%), 40 yo (n=3, 10%), 50 yo (n=5, 16%), 60 yo (n=2, 6%) cohorts. Four patients (8%) showed tooth displacement. Six patients (12%) showed progressive gingival recession. There were no relationships between tooth wear and arch location, or gender or bruxing habits or GERD history. Conclusions: Our descriptive data show four important findings: 1) progressive tooth wear occurred in most patients; 2) only 1-2 teeth per arch showed moderate wear; 3&4) progressive tooth displacement and gingival recession in adults was uncommon. This methodology is easy to implement in a dental clinic.