Influence of Nd:YAG laser on intrapulpal temperature and bond strength of human dentin under simulated pulpal pressure

• Published in: Lasers in medical science Vol. 31; no. 1; pp. 49 - 56
• Main Authors: Silva, T. M., Gonçalves, L. L., Fonseca, B. M., Esteves, S. R. M. S., Barcellos, D. C., Damião, A. J., Gonçalves, S. E. P.
• Format: Journal Article
• Language: English
• Published: London Springer London 01.01.2016; Springer Nature B.V
• Subjects: Adhesiveness; Adhesives; Analysis of variance; Bond strength; Bonding strength; Composite Resins - chemistry; Curing Lights, Dental; Dental Pulp; Dentin; Dentin - chemistry; Dentin - radiation effects; Dentistry; Human; Humans; Irradiation; Lasers; Lasers, Solid-State; Medicine; Medicine & Public Health; Optical Devices; Optics; Original Article; Photonics; Pressure; Quantum Optics; Simulation; Teeth; Temperature; Tensile Strength; Nd:YAG laser; Intrapulpal pressure; Temperature; Adhesion
• ISSN: 0268-8921; 1435-604X
• DOI: 10.1007/s10103-015-1827-1

The aim of this study was to evaluate the effects of simulated pulpal pressure (SPP) on the variation of intrapulpal temperature (Δ T ) and microtensile bond strength (μTBS) to dentin submitted to an adhesive technique using laser irradiation. One hundred sound human molars were randomly divided into two groups ( n  = 50), according to the presence or absence of SPP (15 cm H 2 O). Each group was divided into five subgroups ( n  = 10) according to Nd:YAG laser energy (60, 80, 100, 120, 140 mJ/pulse). The samples were sequentially treated with the following: 37 % phosphoric acid, adhesive (Scotchbond Universal), irradiation with Nd:YAG laser (60 s), and light curing (10 s). Δ T was evaluated during laser irradiation using a type K thermocouple. Next, a composite resin block was build up onto the irradiated area. After 48 h, samples were submitted to microtensile test (10 kgf load cell, 0.5 mm/min). Data were analyzed by two-way ANOVA and Tukey tests ( p  = 0.05). ANOVA revealed significant differences for Δ T and TBS in the presence of SPP. For Δ T , the highest mean (14.3 ± 3.23 °C) A was observed in 140 mJ and without SPP. For μTBS, the highest mean (33.4 ± 4.15 MPa) A was observed in 140 mJ and without SPP. SPP significantly reduced both Δ T and μTBS during adhesive procedures, lower laser energy parameters resulted in smaller Δ T , and the laser parameters did not influence the μTBS values.