Evaluation of Er:YAG and Er,Cr:YSGG laser irradiation for the debonding of prefabricated zirconia crowns

Abstract

Background. Reduced tooth structure in the pediatric and adolescent population is frequently restored with prefabricated zirconia crowns. On permanent teeth, these restorations may need to be removed and replaced with permanent restorations. Objectives.To explore and compare the use of 2 high-powered erbium lasers for removing prefabricated zirconia crowns from molar teeth as a non-invasive alternative to rotary instruments.Material and methods. Twenty-five permanent molars were prepared to dentin and prefabricated all-ceramic zirconia crowns were fitted and cemented with resin modified glass ionomer (RMGI) cement. The teeth were randomly assigned into one of the 2 retrieval treatment groups: the erbium-doped yttrium, aluminum and garnet (Er:YAG) laser group (G1; n = 12) or the erbium, chromium-doped yttrium, scandium, gallium and garnet laser (Er,Cr:YSGG) laser group (G2; n = 13). The laser operating parameters for the Er:YAG laser were 300 mJ, 15 Hz, 4.5 W, and 50-microsecond pulse duration (SSP mode); for the Er,Cr:YSGG laser, they were 4.5 W, 15 Hz, 20 water/20 air, and 5 W, 15 Hz, 50 water/50 air, and 60-microsecond pulse duration (H mode). The experiment was repeated twice. The surface area and the volume of teeth and crowns were measured and the cement space was calculated. The retrieval time and temperature changes were tested and recorded. The data were analyzed with the t-test. The surfaces of the dentin and the crown from each group were further examined using scanning electron microscopy (SEM).Results. The average time for crown removal using the Er:YAG laser was 1 min 32.7 s; for the Er,Cr:YSGG laser it was 3 min 13.9 s (p < 0.0001). The mean temperature changes were 1.41 ±1.36°C for the Er:YAG laser and 2.2 ±0.99°C for the Er,Cr:YSGG laser (p = 0.0321). The SEM examination showed no damage or major structural changes caused by treatment with either erbium-family laser.Conclusions. Both lasers are effective, non-invasive tools to remove prefabricated zirconia crowns cemented with resin cement and should be considered as viable alternatives to rotary instrumentation.

Erbium laser‐assisted ceramic debonding: a scoping review

“…Time for removal was not always statistically different. However, the debonding times in general tend to be shorter for the Er:YAG laser compared to the Er,Cr:YSGG laser 20,27,29,31,50 . Both erbium lasers feature comparable times to debond orthodontic brackets (Table 2), 10,29,31 and do not result in the temperature increase inside the tooth 27 .…”

“…Fifteen out of 38 studies (Tables 2, 3, 4, and 5) examined the debonded ceramics. Scanning electron microscopy (SEM) was the most common method of examination 7,8,10,13,20,21,26,29,37,48,50,53 . SEM was sometimes applied with energy dispersive spectroscopy (EDS), 20,37 secondary electron imaging (SBI), or backscattered electrons (BSE) 10 .…”

“…Debonding time and pulpal or abutment temperature changes were perhaps the most common outcome measures used in determining the effectiveness of laser assisted debonding. A majority of the studies measured both debonding time and temperature changes 7,8,10,20,38,44,46,48–50 . Laser transmission energy was also used in relation to the laser application 39,54 .…”

“…Both erbium lasers feature comparable times to debond orthodontic brackets (Table 2), 10,29,31 and do not result in the temperature increase inside the tooth 27 . While both erbium lasers are efficient in removing zirconia crowns from teeth or implant abutments, Er:YAG laser accomplishes the task faster than Er,Cr:YSGG 20,50 . While power of 3 Watt, 10 seconds in the scanning mode with energy density 22‐28 J/cm2, pulse duration of 100 μs seems to be adequate for orthodontic bracket removal, 31 crown removal requires laser settings to be in the range of at least 3.5 and 4 Watt of power with 25 Hz pulse rate 47 .…”

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

“…Nosso estudo de análise temperatura correlacionando com a espessura do esmalte é pioneiro na área, além de termos uma metodologia criteriosa com termopares de resposta rápida tipo K com espessura de 127 µm e presença de grupos controles utilizando o instrumento rotatório diamantado. Golob-Deeb et al (95) também analisou os aumentos de temperatura durante a remoção de zircônias com laser Er:YAG e Er,Cr:YSGG e observou mudanças médias de temperatura de 1,40 ± 1,36 °C para o laser Er:YAG e 2,2 ± 0,99 °C para o laser Er,Cr:YSGG, concluindo que todas as temperaturas pulpares observadas permaneceram dentro de uma faixa segura, mas salienta que esses aumentos de temperatura devem ser interpretados com cautela, pois sofrem influência de outros fatores, como as temperatura do ambiente e água durante as irradiações. Além desse estudo, Alikhasi et al (94) também observou em seu trabalho que o aumento da temperatura intrapulpar foi inferior a 1 °C em todos os grupos de sua pesquisa.…”