Effect of Nd:YAG laser and acidulated phosphate fluoride on bovine and human enamel submitted to erosion/abrasion or erosion only: an in vitro preliminary study.

Photomedicine and laser surgery

PubMedID: 19712017

Sobral MA, Lachowski KM, de Rossi W, Braga SR, Ramalho KM. Effect of Nd:YAG laser and acidulated phosphate fluoride on bovine and human enamel submitted to erosion/abrasion or erosion only: an in vitro preliminary study. Photomed Laser Surg. 2009;27(5):709-13.
OBJECTIVE
The aim of the present in vitro study was to evaluate, using two different methodologies, the effectiveness of pulsed Nd:YAG laser irradiation associated with topical acidulated phosphate fluoride (APF) for preventing enamel erosion and structure loss under regimes of erosion and abrasion or erosion only.

BACKGROUND DATA
An increased incidence of noncarious lesions (erosion and abrasion) has been observed, consequently new preventative therapies have been proposed.

MATERIALS AND METHODS
Two different methodologies were performed. For the first, 100 bovine crowns were submitted to four different treatments (n = 25): no treatment (control), 4 min application of APF, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 141.5 J/cm(2)), and Nd:YAG laser irradiation + 4 min of APF. After the specimens were exposed to citric acid (2% w/v; 30 min), they were submitted to 5000 brushing cycles. Specimen mass was measured before and after the treatments. For the second methodology, 20 human crowns were embedded in acrylic resin and cut surfaces were exposed and polished. The specimens were divided into four groups (n = 10): no treatment (control), APF for 4 min, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 125 J/cm(2)), and Nd:YAG laser irradiation + APF. The samples were then immersed in citric acid (2% w/v; 90 min). Vickers hardness was obtained before and after the treatments.

RESULTS
The Nd:YAG laser irradiation + APF (bovine and human enamel) was more effective and yielded statistically significant results for surface microhardness and enamel wear.

CONCLUSION
Nd:YAG laser irradiation associated with APF reduced bovine enamel wear and human enamel softening when samples were submitted to a regime of erosion and abrasion or erosion only in vitro.