Treatment of Dentinal Hypersensitivity by means of Nd:YAP Laser: A Preliminary In Vitro Study

Abstract EN

Objective.

The aim of this study is to evaluate the effectiveness of Nd:YAP laser to seal dentinal tubules at different parameters.

Material and 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.