Low-level laser therapy as an alternative for pulpotomy in human primary teeth

This study aimed to evaluate the effects of low-level laser therapy (LLLT) on pulpal response of primary teeth. Twenty mandibular primary molars were randomly divided into the following groups: group I Buckley's formocresol (diluted at 1:5), group II calcium hydroxide, group III LLLT + zinc oxide/eugenol, and group IV LLLT + calcium hydroxide. LLLT parameters were set at 660-nm wavelength, 10-mW power output, and 2.5 J/cm(2) energy density for 10 s in continuous mode (InGaAlP laser, Twin Laser®, MMOptics, Sao Carlos, Sao Paulo, Brazil). The teeth were extracted at the regular exfoliation period. The dentin-pulp complex was graded by an established histopathological score system. Statistical analysis was performed by Kruskal-Wallis and chi-square test. The histopathological assessment revealed statistically significant differences among groups (P < 0.05). The lowest degree of pulpal inflammation was present in LLLT + calcium hydroxide (P = 0.0296). Calcium hydroxide showed the highest rate of hard tissue barrier (P = 0.0033), odontoblastic layer (P = 0.0033), and dense collagen fibers (P = 0.0095). On the other hand, formocresol showed the highest incidence of internal resorption (P = 0.0142). Based on this study, low-level laser therapy preceding the use of calcium hydroxide exhibited satisfactory results on pulp tissue healing. However, further clinical studies on human teeth with long-term follow-up are needed to test the low-level laser therapy efficacy.