The effects of using erbium, chromium-doped:yttrium-scandium-gallium-garnet laser on the surface modification, bacterial decontamination, and cell adhesion on zirconia discs: an in vitro study.

ABSTRACT

The use of zirconia for implants and abutments has become more prevalent in implant dentistry as an alternative to the commonly used titanium implants, and peri-implant disease can still affect them. The erbium, chromium-dopedyttrium-scandium-gallium-garnet (Er, CrYSGG) laser has emerged as a promising treatment modality. The purposes of this in vitro study were to (1) determine the effects of the laser on the surface roughness of zirconia discs; (2) determine the extent of removal of a single species biofilm, E. coli, on the zirconia discs after applying the laser; (3) determine the amount of cell adhesion and proliferation utilizing fibroblasts on zirconia discs after treatment with the laser. All treatments will be compared with the commonly used ultrasonic instrumentation and hand scalers. For the first aim, gross examination revealed noticeable surface damage on the discs when using ultrasonic and scalers but not for the laser group. For surface roughness, the mean roughness was Pa= 0.623±0.185 µm, 0.762±0.421 µm, 0.740±0.214 µm, and 0.724±0.168 µm for control discs, and discs treated with either the Er,CrYSGG laser, ultrasonic instrumentation, and hand scalers respectively. There was no statistical significance among the groups (p=0.628). For bacteria decontamination, there was a statistical significance among the groups (p< 0.0001). Statistical significance was seen between the control group and each of the three treatment groups, favoring the treatment groups (p< 0.0001). Statistical significance was seen when comparing ultrasonic instrumentation and hand scalers (p= 0.000) as well as when comparing the Er,CrYSGG laser to hand scalers (p= 0.007), favoring both the ultrasonic instrumentation and Er,CrYSGG laser. No significance between the Er,CrYSGG laser group and the ultrasonic instrumentation group was noted (p =0.374). When comparing the cell attachment following treatment in each of the three groups and also without treatment (control), there was a statistical significance among the groups (p<0.0001) in terms of total cell count, favoring the control and the laser groups. Further evaluations with SEM showed differences in cell morphology indicating more adherent cells on Er,CrYSGG laser-treated surfaces. In conclusion, gross examination of the discs show clear surface changes when using ultrasonic instrumentation and hand scalers compared to the Er,CrYSGG laser group. The Er,CrYSGG laser was able to effectively ablate bacteria from zirconia disc. Fibroblast attachment on the surfaces of the zirconia discs shows more adherence when treated with Er,CrYSGG laser.