Effect of different non-invasive and micro-invasive treatment modalities of white spot lesions on microhardness of human enamel

Aim: to investigate effect of different treatment modalities of white spot lesions on microhardness of human enamel.
Materials and methods: twenty-four recently extracted sound human maxillary incisor teeth were collected. Teeth were divided at random into six groups (10 each) that were summarized as follows: Group 1: sound unprepared teeth (base line control); Groups 2: demineralized enamel (negative control), Group 3: Demineralized enamel treated by resin infiltration (ICON), Group 4: demineralized enamel treated by bioactive glass (Sylc powder) as remineralizing agent, Group 5: demineralized enamel treated by fluoride varnish ( positive control), Group 6: Demineralized enamel treated by microabrasion. Teeth were embedded in the acrylic blocks with their labial surface flushed with the flat surface of the mold. All specimens except the base line control specimens were demineralized. Each group was treated with the assigned treatment according to manufacturer’s recommendations. The microhardness measurements were performed using a Vickers Microhardness Tester with a Vickers diamond indenter and a 20X objective lens.
Results: showed that there was a statistically significant difference in MH values between different study groups (P<0.001). The significantly highest MH mean values were recorded in (microabrasion), (sound enamel), (resin infiltration), and (Sylc powder) groups, which did not differ significantly. This was followed by the mean value of (fluoride varnish) group. While (demineralized enamel) group yielded significantly lowest MH values.
Conclusions: among the tested treatment modalities, microabrasion, resin infiltrant as well as bioactive glass air abrasion improved enamel surface microhardness in comparison to fluoride varnish.