Morphological, optical, and elemental analysis of dental enamel after debonding laminate veneer with Er,Cr:YSGG laser: A pilot study

Abstract

Laminate veneer removal is becoming a routine procedure at the dental clinic and the use of laser can facilitate its removal. This work aimed to evaluate the morphological, elemental, and optical changes in the remaining enamel after veneer removal using Er,Cr:YSGG laser. Forty‐four enamel slabs were prepared and randomly distributed into nine experimental groups, for bonding using lithium disilicate laminates with three different luting agents (Variolink Veneer, RelyX U200, and RelyX Veneer). Then each agent was debonded using Er,Cr:YSGG laser (2.78 μm) using two different protocols:3.5 W, 48.14 J/cm2, 20 Hz non‐contact and 3.0 W, 48.14 J/cm2, 20 Hz non‐contact. The morphological, optical, and elemental analysis of enamel was performed before cementation and after laser debonding, using scanning electron microscopy (SEM), optical coherence tomography (OCT), and energy‐dispersive X‐ray spectroscopy (EDS). The level of statistical significance adopted was 5%. The EDS analysis of enamel after debonding revealed a significant increase in silane and carbon, as well as a decrease in calcium and phosphate contents. Analysis showed the presence of residual cement in most experimental groups but the morphological analysis showed alteration of the enamel's prisms only in the groups that used RelyX Veneer and Variolink Veneer cements. There was no evidence of deleterious morphological changes resulting from irradiation. However, an increase in the optical attenuation coefficient by the OCT was observed due to the presence of the remaining cement. It can be concluded that the Er,Cr:YSGG laser, in the mean powers used, is efficient for veneer removal without causing deleterious effects for the enamel.

Evaluation of the time needed for the debonding of two ceramic materials at two thicknesses using two laser powers of Erbium Chromium: YSGG Laser “A Comparative In-Vitro Study”

“…9,26 Both laser power outputs (3 watt and 6 watt) were selected as they were reported to be effective in debonding ceramic restorations. This was in accordance to Zanini et al and Giraldo et al 20,27 The quality of the laser is highly affected by the distance between the laser head and the surface. It was recommended by literature to set the distance to 3-5 mm as it was proven to be more efficient than the contact mode type in decreasing the debonding time and in allowing for further heat diffusion without causing the probable thermal damage.…”

Erbium laser‐assisted ceramic debonding: a scoping review

“…Based on reported data, type of cement plays a role in the debonding time and has been associated with structural changes seen on microscopic and electron microscopic analyses 7,8,10,13,20,21,26,29,30,32,38,43,48,50,53 . While Er,Cr:YSGG laser was deemed efficient for veneer (Table 3) removal without causing deleterious effects to the enamel, presence of residual cement and changes in enamel prism structure were observed in association with certain resin cements (RelyX Veneer, 3M‐ESPE and Variolink Veneer, Ivoclar Vivadent) 37 . Resin cements in general are greatly affected by the erbium laser irradiation, however the ablation thresholds and ablation volume loss are dependent on the chemical composition of a particular resin cement.…”

Estudo >i<in vitro>/i< para determinação de protocolo de irradiação para remoção de facetas cerâmicas em esmalte dental com >i<laser>/i< de Er,Cr:YSGG

“…Zhang et al (33) utilizaram o laser de Er:YAG para remover 12 facetas cerâmicas cuja composição não foi detalhada pelos autores e assim como nós, realizaram uma análise morfológica do esmalte irradiado pelas imagens geradas pelo MEV e também constataram que a remoção ocorreu sem ablação ou danos a qualquer estrutura dentária. No entanto, este trabalho não apresentava grupos controle para comparar as análises morfológicas, como encontrado no trabalho de Zanini et al (36) , trabalho publicado pelo nosso grupo com o estudo piloto desta dissertação.…”

“…Nosso trabalho foi pioneiro no uso das análises de EDS e OCT, dados estes já publicados na literatura com os resultados de nosso estudo piloto em 2020 (36) . O resultado das medidas com a técnica de EDS comprovou, por meio dos valores de elementos químicos presentes no esmalte e nos cimentos resinosos, que após a remoção das facetas observamos cimento resinosoresidual, que mesmo ocorrendo a fotoablação, a mesma não ocorre em toda a superfície.…”

“…Mas os estudos na área devem avançar agora com o enfoque de como o esmalte já irradiado com laser de Er,Cr:YSGG irá reagir a uma nova cimentação já que a técnica de OCT mostrou alterações no coeficiente de atenuação do esmalte. (36) Karagoz-Yildirak et al (30) realizaram a recimentação com "redeboding" e constataram que a remoção das cerâmicas usando o laser de Er:YAG não afetou os valores da força de "redebonding", mas .para o laser de Er:YAG. A importância em se pensar como irá funcionar a adesão em esmalte já irradiados se dá ao fato que os pacientes são submetidos a procedimento de reabilitação com facetas cada vez mais precoces, com maior chance de ser necessário refazer as facetas ao longo da vida.…”