Objectives: This study aimed to evaluate the effect of Er, Cr: YSGG LASER, fluoride varnish, and their combination on treating white spot lesions before and after pH cycling.
Methods: A total number of fifteen freshly extracted intact human molars were used. The teeth crowns were sectioned buccolingual and mesiodistal to form four quadrants resulting in 60 specimens. They were divided into six groups of ten. I1: positive control (sound enamel), I2: negative control (demineralized enamel), I3: Er, Cr: YSGG LASER, I4: fluoride varnish, I5: Er, Cr: YSGG LASER followed by fluoride varnish, I6: fluoride varnish and then Er, Cr: YSGG LASER. Enamel microhardness (SMH) was measured for all these six groups. All groups were subjected to a pH cycling for three days model except the I1 group. Enamel SMH was measured again after pH cycling.
Results: The mean SMH values before pH cycling showed no statistically significant difference between all the tested groups. After pH cycling, there was a statistically significant difference in the mean SMH values p=0.001, where I2 showed the lowest statistically significant mean SMH values and I5 showed the highest. When comparing each tested group separately before and after pH cycling the mean SMH values statistically significantly increased only in I3 and I5 groups where p= 0.027 and 0.047 respectively.
Conclusion: The use of Er, Cr: YSGG LASER with the tested specifications followed by fluoride application is an effective method for enhancing remineralization. pH cycling is necessary to examine the effect of the different remineralization protocols.