In vitro evaluation of different techniques for aesthetic treatment of enamel white spot lesions after orthodontic treatment

Objective To evaluate two in vitro methods (microabrasion and resin infiltration) for the aesthetic treatment of white spot lesions in enamel after orthodontic treatment. Methods The sample consisted of 40 human teeth, divided into two groups: Microabrasion and Resin Infiltration. Orthodontic brackets were bonded to the teeth, which were subjected to a dynamic DEM-REM cycle to induce lesions. After debonding, microabrasion (Whitness RM − FGM) and resin infiltration (ICON - DMG) were performed. The variables evaluated were: color (spectrophotometer), surface roughness (contact profiler − Ra), mineral content (micro-Raman spectroscopy and EDS), and surface micromorphology (scanning electron microscope − SEM). All tests were conducted at baseline, after the DEM-REM cycle, and after treatments. Color and roughness were analyzed by the Kruskal-Wallis test (= 5%); Micro-Raman data, SEM images, and EDS were described qualitatively. Results Color (ΔE) and roughness were altered after white spot induction but returned to baseline values after treatments regardless of the group (p>0.05). Enamel surface mineral content (EDS) returned to baseline levels after microabrasion, which was corroborated by PO43- peaks (micro-Raman). In surface micromorphology, microabrasion exhibited a smooth and polished surface, and infiltration a dense surface with small irregularities. Conclusion Both techniques were successful in masking white spot lesions, with final color and roughness similar to that of sound enamel. The mineral content of microabrasion-treated enamel resembled that of sound enamel, while infiltration showed a slight reduction. After both treatments, the enamel surface appeared smooth and mineralized; in the resin infiltration group, discreet protrusions were observed.