Treatment of dentinal hypersensitivity by means of Nd:YAP Laser: a preliminary in vitro study.
OBJECTIVE
The aim of this study is to evaluate the effectiveness of Nd:YAP laser to seal dentinal tubules at different parameters.


METHODS
24 caries-free human wisdom impacted molars were used. The crowns were sectioned transversally in order to totally expose the dentin. The smear layer was removed by a 1 min application of EDTA. Each surface was divided into four quadrants, but only three quadrants were irradiated at a different output power setting (irradiation speed: 1 mm/sec; optical fiber diameter: 320 µm; tangential incidence of beam and in noncontact mode). Samples were smeared with a graphite paste prior to laser irradiation. All specimens were sent for SEM analysis. Pulp temperature increases in additional twenty teeth were measured by a thermocouple.


RESULTS
Morphological changes in dentin surfaces depend on the value of used energy density. Higher energy densities (2 W-4 W; 200-400 mJ; pulse duration: 100 m sec.; and 10 Hz) induce higher dentin modifications. Our results confirmed that Nd:YAP laser irradiations can lead to total or partial occlusion of dentin tubules without provoking fissures or cracks. Measurements of pulp temperature increases showed that Nd:YAP laser beam can be considered as harmless for pulp vitality for following irradiation conditions: 2 W (200 mJ) to 4 W (400 mJ) with an irradiation speed of 1 mm/sec; fiber diameter: 320 micrometers; 10 Hz; pulse duration: 100 m sec; noncontact mode and in tangential incidence to exposed dentin. The perpendicular incidence of the laser beam on exposed dentin may injure pulp vitality even at low output power of 3 W.


CONCLUSIONS
Nd:YAP laser beam was able to seal the dentin tubules without damaging dentinal surfaces and without harming pulp vitality. Nd:YAP laser is effective and may be safely used for future in vivo treatments of dentinal hypersensitivity under certain conditions.
Department of Operative Dentistry and Endodontology, Ghent Dental Laser Center, Dental School, Ghent University, 9000 Ghent, Belgium.
Amaury
A
Namour
Department of Dental Sciences, Faculty of Medicine, University of Liege, 4000 Liege, Belgium.
Samir
S
Nammour
L.A.S.M.O.S, Facultés Universitaires Notre Dame de la Paix, 5000 Namur, Belgium.
André
A
Peremans
Department of Dental Sciences, Faculty of Medicine, University of Liege, 4000 Liege, Belgium.
Daniel
D
Heysselaer
Department of Operative Dentistry and Endodontology, Ghent Dental Laser Center, Dental School, Ghent University, 9000 Ghent, Belgium.
Roeland J G
RJ
De Moor
D003782:Dental Pulp / Q000473:pathology / Q000528:radiation effects*; D003786:Dental Pulp Cavity / Q000473:pathology / Q000528:radiation effects*; D003804:Dentin / Q000473:pathology / Q000528:radiation effects; D003807:Dentin Sensitivity / Q000473:pathology / Q000628:therapy*; D006801:Humans; D053685:Laser Therapy; D007834:Lasers