Inter- and intra-variability in tooth wear progression at surface-, tooth- and patient-level over a period of three years: A cohort study: Inter- and intra-variation in tooth wear progression.

Objective: To explore the variability of tooth wear progression at the surface-, tooth- and patient-level over a period of three years three years using in vivo 3D-measurements of full dentitions amongst patients with moderate to severe tooth wear and without demand for restorative rehabilitation.

Methods: Fifty-five eligible patients with moderate to severe tooth wear had intra-oral scans taken using either the 3 M True Definition Intraoral Scanner or the 3 M Lava Chairside Oral Scanner. The maximum height loss (µm) per cusp/incisal/palatal surface at unrestored surfaces was measured using the 3D Wear Analysis (3DWA)-protocol with Geomagic Qualify, resulting in sixty-four measurements per dentition. Data was visualized using box plots. Correlation was calculated between tooth wear progression rates of different tooth types and surfaces.

Results: Thirty patients with scans at intake and after three years were included (38 ± 8 years, 77% M, 23% F). Mean observation time was 3.1 ± 0.2 years. Surface measurements (N = 1,615) showed a high deviation and a high number of outliers at all surfaces, indicating large variability amongst the surfaces, tooth types and patients with tooth wear progression rates. Correlations between regions were very low: anterior-molar region -0.219, anterior-premolar region 0.116 and premolar-molar region 0.113. Correlations between the surfaces of molars were also low (between 0.190 and 0.565).

Conclusions: In a group of patients with moderate to severe tooth wear, large differences in wear progression were found within and amongst patients. Tooth wear progression is therefore highly individualized and can be very localized.

Clinical Significance: This study confirms the necessity of individual management of patients with moderate to severe tooth wear. Effective monitoring of tooth wear is important when deciding the timing and need for restorative intervention.

Clinical Trial Registration Number: NCT04790110.