Debonding of LDSVs utilising Er,Cr:YSGG laser irradiation with fractional technique: an in vitro study

Abstract

Background: The removal of porcelain laminate veneers with rotary instruments could be accompanied by microfractures because differentiation of the veneer from the dental structure and resin cement is not a highly selective procedure. This can lead to scratches and overheating of the enamel and patient discomfort. Therefore, this in vitro research aimed to examine the effectiveness of the 2790 nm Er,Cr:YSGG laser utilizing a fractional technique to debond lithium disilicate veneer. Methods: Six groups of 30 extracted permanent bovine mandibular incisors were selected. Twenty-five samples, G1-5, (n = 5) laser-irradiated groups, and the last five samples (C) were considered the control group. The tested groups were irradiated with 3-5 W output power of Er,Cr:YSGG laser for time intervals of 50 s. During irradiation, the temperature in the pulp chamber was monitored using a thermocouple connected to a digital multilogger thermometer inside the sample's pulp chamber. Subsequently, the shear bond strength was measured for all groups. Furthermore, the remaining adhesive index was measured using a stereomicroscope, the area was analysed, and then transformed into scores. Finally, one untreated sample and two samples of the highest power value from laser-treated groups were examined using a scanning electron microscope (SEM) for their surface morphology. Results: All debonding protocols were safe regarding intrapulpal temperature increment. The highest temperature elevation was recorded at 5 W, which increased by 1.7 °C. Considering the shear bond strength measurement, there was a significant reduction after laser irradiation for G1-5 compared with group C. Conclusions: Er,Cr:YSGG laser with a fractional technique can be used successfully for veneer removal. Besides safe temperature rising, veneers can be reused because there was neither a fractured specimen during the whole study nor major irregularities or cracks shown in SEM pictures analysis for the veneer surfaces; thus, they can be removed quickly, safely, and comfortably using Er,Cr:YSGG.

Optimized Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Parameters for the Removal of Dental Ceramic Restorations

“…Er:YAG laser-assisted debonding may be an alternative to conventional debonding for monocrystalline ceramic brackets [19][20][21]. Er,Cr:YSGG laser irradiation with a fractional technique was effectively used for porcelain laminate veneer removal [22].…”