Effect of erbium, chromium: yttrium, scandium, gallium, garnet laser and casein phosphopeptide-amorphous calcium phosphate on surface micro-hardness of primary tooth enamel

OBJECTIVE: The aim was to evaluate the effect of Er, Cr: YSGG laser and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on surface micro-hardness of primary tooth enamel. MATERIALS AND METHODS: A total of 30 freshly extracted caries free primary anterior teeth were cleaned and stored in 1% thymol. Teeth were embedded in acrylic resin such that only their buccal surfaces were exposed and were divided into four groups. Group I: Five intact teeth (negative control). The remaining 25 teeth were immersed for 30 min in 1% citric acid for demineralization. Group II: Five demineralized teeth (positive control), Group III: CPP-ACP (GC tooth mousse-GC International, Itabashi-Ku, Tokyo, Japan) application and Group IV: Etching using Er, Cr: YSGG laser + CPP-ACP application. Groups III and IV were subjected to pH cycling for 5 days. Surface micro-hardness of all the teeth was measured using Brinell hardness tester (Fuel Instruments and Engineers Pvt. Ltd.). Data were analyzed using ANOVA. RESULTS: Mean surface micro-hardness of Groups I and II were 177.43 kgf/mm(2) and 164.86 kgf/mm(2), respectively. Group IV showed a higher mean surface micro-hardness (230.68 kgf/mm(2)) compared with that of Group III (190.28 kgf/mm(2)). In comparison to all other groups, laser etching prior to CPP-ACP application increased surface micro-hardness significantly (P < 0.001). CONCLUSION: Laser irradiation of primary teeth followed by CPP-ACP application increased surface micro-hardness of enamel.