Vertical reflection intensity, roughness, and tactile sensation of caries-inactive, caries-active and sound enamel surfaces: an in vitro study.

OBJECTIVES

This study evaluated whether reflection intensity, roughness and tactile sensation differs between caries-inactive, caries-active and sound enamel surfaces.

METHODS

Pooled permanent teeth were assessed using surface texture and color. Teeth with caries-inactive (Ci, n = 55), caries-active (Ca, n = 59) and sound (S, n = 13) vestibular or proximal surfaces were selected. Vertical reflection intensity (VRI) and roughness parameters, including mean linear (Ra), area-related (Sa) and volume-related (Vmc) of Ci, Ca and S were assessed using a multi-sensor microscope (MicroProf®100,FRT GmbH) with a conventional or an experimental handheld chromatic-confocal optic and a 3D-laser-scanning-microscope (VK-X110,Keyence). VRI and roughness values for caries-active surfaces were obtained from a previous study, while blinded tactile assessment for these surfaces was repeated. Two experienced examiners evaluated the tactile sensation using two explorers (405/CP11, S23H) (n = 20).

RESULTS

For all roughness parameters significant differences between caries surfaces and adjacent sound surfaces on the same teeth could be observed (p ≤ 0.029, Wilcoxon). For VRI significant differences were only observed for caries-active surfaces (p < 0.001). Across Ci, Ca and S significant difference could be observed for all roughness parameters (p ≤ 0.012, Bonferroni) and VRI (p < 0.001), except for VRI between Ci and S (p ≥ 0.390). No significant difference in VRI was observed between both optics (p > 0.05, Bonferroni). The positive predictive value (PPV) differed between examiner 1 (S23H: Ci:30 %; Ca:83 %; S:97 %, 405CP11: Ci:27 %; Ca:74 %; S:91 %) and examiner 2 (S23H: Ci:20 %; Ca:72 %; S:84 %, 405CP11: Ci:23 %; Ca:68 %;S; 85 %).

CONCLUSION

Optical measurement and tactile methods revealed significant differences between active, inactive, and sound enamel surfaces. However, the diagnostic accuracy varied between explorers and examiners.

CLINICAL SIGNIFICANCE: Active, inactive, and sound enamel surfaces showed significant differences in roughness and reflection intensity. While both optical methods are not yet applicable intraorally, tactile assessment showed strong variabilities between examiners and dependence on the type of dental explorer used, especially when simulating non-visible areas.