The Effect of Nd:YAG Laser and Casein- Phosphor-Peptide-Amorphous Calcium Phosphate with Fluoride on Dental Enamel De-mineralization: In vitro study

The aim of the study was to evaluate a new treatment modality to decrease dental enamel demineralization via combing the effect of pulsed Neodymium Yttrium Garnet (Nd:YAG) laser (1064 nm) and Re-mineralizing paste(CPP-ACP containing sodium fluoride) regarding the tooth pulp chamber temperature elevation, calcium concentration dissolute from enamel surfaces and the dental enamel absorption of methylene blue stain by assessing (R red ,G green ,B blue)values. Sixty human permanent premolars were used for measuring calcium concentration dissolution and (R,G,B)s values. They randomly divided into six groups: the negative control group (A) received no treatment, and the positive control group (B) where the re-mineralizing paste was applied without laser irradiation. For the groups (C), (D), (E) and (F) the (1064 nm) pulsed Nd:YAG laser was used in two dose settings. The lower laser dose setting at (60 mJ) for the C and D groups,and the higher laser dose setting at (170mJ)for E and F groups respectively. Groups D and E in addition to laser irradiation the Re-mineralizing paste was applied. The atomic absorption photometry test results showed that groups C, and D were statistically different compared to the groups A and B (p<0.001) in the reduction of calcium dissolution, Whereas Groups E and F shown non-significant reduction in calcium dissolution compared to control groups. Twenty teeth were used to assess the temperature elevation during irradiation using a K-type thermocouple at 37 ± 0.5 C, divided for ten teeth for each irradiation settings. The maximum tempers of temperature test showed that the maximum temperature increases for group E was very high significant difference (p<0.05) over that of groups C. The (R,G,B)s value test showed that groups C and D having lower affinity to absorb methylene blue stain, and they are statically significant different compared to the groups A and B .while groups E and F showing a higher affinity to absorb methylene blue stain compared to control groups.