Exploratory Analysis of Objective Outcome Measures for the Clinical Assessment of Erosive Tooth Wear.

This study proposed using enamel surface texture and thickness for the objective detection and monitoring of erosive tooth wear (ETW), comparing them to the standard subjective Basic Erosive Wear Evaluation (BEWE). Thirty-two subjects (n = 597 teeth) were enrolled in this longitudinal observational clinical study. Enamel thickness (by cross-polarization optical coherence tomography, CP-OCT) and 3D dental microwear parameters, i.e., area-scale fractal complexity (Asfc), anisotropy (Str), and roughness (Sa) (by white-light scanning confocal profilometry), were obtained from buccal surfaces. Buccal, occlusal, and lingual surfaces were scored for BEWE and the maximum score per tooth (BEWEMax) was determined at baseline and 12 months (M12). Data outcome relationships were evaluated (alpha = 0.05). Enamel thickness decreased (p < 0.001), BEWE scores, Sa, and Str increased (p < 0.001), while Asfc did not change at M12. Baseline BEWEBuccal correlated strongly with BEWEMax (r = 0.86, p < 0.001) and moderately with BEWELingual (r = 0.42, p < 0.001), but not with enamel thickness (r = 0.03, p = 0.43). Change (Δ) in surface texture outcomes correlated poorly but significantly with ΔBEWEBuccal (r = -0.15-0.16, p < 0.001) and did not correlate with Δenamel thickness (r = 0.02-0.09, p > 0.06). Teeth with BEWE progression revealed a greater increase in ΔSa and ΔStr. These findings suggest that enamel surface roughness can potentially determine ETW severity, and CP-OCT may be relevant for clinically monitoring enamel thickness.

Toothbrush bristle configuration and brushing load: Effect on the development of simulated non-carious cervical lesions.

OBJECTIVES: This study investigated the effect of toothbrush bristle configuration and brushing load on the development of non-carious cervical lesions (NCCLs). METHODS: Human premolars were mounted on acrylic blocks and had their root surfaces partially covered with acrylic resin to simulate gingiva, leaving a 2-mm length area apical to the cemento-enamel junction exposed for brushing. The teeth were brushed under 1- or 3 N load with one of the following toothbrushes (n = 16): a) ordinary/flat-trimmed (Oral-B Indicator); b) rippled (Oral-B Contour); c) cross-angled/multileveled/rubber bristles (Oral-B Pro-Health All-in-One); d) cross-angled/multileveled/flex head (Oral-B Pro-Flex); e) feathered (Oral-B Compact Clean). Brushing was performed using toothpaste slurry (Crest Cavity Protection) for 55,000 double-strokes in back-and-forth motion, to simulate 10 years of brushing. Impressions were taken at baseline and after brushing and scanned by a 3D optical profilometer. The lesions formed were evaluated for volume loss, angle, and shape. RESULTS: The ordinary/flat-trimmed toothbrush caused significantly higher volume loss (3.81 mm3) in comparison to the other toothbrushes (2.56-2.92 mm3). The toothbrush having rubber bristles was associated with NCCLs showing the smallest angle and, along with the rippled toothbrush (53.1%), provoked higher proportion of wedge-shaped lesions (43.8%), whereas teeth brushed with the feathered toothbrush exhibited the lowest prevalence of wedge-shaped lesions (3.1%). The 1- and 3 N load applied during brushing affected neither volume loss nor lesion angle. CONCLUSIONS: At the brushing loads tested, the development of NCCLs was dependent on toothbrush bristle configuration, with the ordinary/flat-trimmed version causing the highest abrasion and the feathered toothbrush the least proportion of wedge-shaped lesions. CLINICAL SIGNIFICANCE: Toothbrush bristle arrangement plays a role in NCCL development, with the ordinary/flat-trimmed version being more abrasive and the feathered toothbrush causing less wedge-shaped lesions.

3D-Image analysis of the impact of toothpaste abrasivity on the progression of simulated non-carious cervical lesions.

OBJECTIVES: To investigate the effect of toothpaste abrasive level on the progression of non-carious cervical lesions (NCCLs) using 3D-image subtraction. METHODS: Upper first premolars were allocated into seven groups (n = 16) of toothpaste/abrasive slurries: A-Zeodent113/5%, B-Zeodent124/10%, C-Zeodent103/15%, D-Sensodyne Pronamel, E-Crest Cavity-Protection, F-Crest Pro-Health-Whitening, and G-Deionized water (DIW). Teeth were mounted on acrylic blocks, and their root surfaces covered with acrylic resin, except for 2-mm near the cemento-enamel junction that was exposed to toothbrushing. Specimens were brushed with the slurries for 5000-, 15,000-, 35,000- and 65,000-strokes. Impressions were taken at baseline and after each brushing time, and then scanned by a 3D optical profilometer. Dentine volume loss was calculated by image subtraction software and subjected to mixed-model ANOVA and multiple comparison tests (α = 0.05). RESULTS: No significant differences among slurries were observed at 5000 and 15,000. At 35,000, F showed higher loss than all other groups except C, which did not differ from the others. At 65,000, F (4.19 ±â€¯3.29 mm3) showed the highest loss, followed by C (2.33 ±â€¯1.47 mm3), which differed from all the other groups except B (1.85 ±â€¯0.91 mm3). Groups B, A (1.35 ±â€¯0.65 mm3), D (1.17 ±â€¯0.48 mm3), E (1.40 ±â€¯0.68 mm3) and G (1.12 ±â€¯0.73 mm3) did not differ from each other. Groups F and C showed significant increase of volume loss starting at 35,000, while B, A, D and E only at 65,000; no increase loss was observed for G. CONCLUSIONS: 3D-image subtraction was able to quantify and differentiate tooth loss, but only at advanced stages. The progression of NCCLs was more evident and faster for highly abrasive slurries. CLINICAL SIGNIFICANCE: Upon root dentin exposure, brushing with lower abrasive dentifrices is advisable to reduce the risk for NCCLs development.