Comparative Study of Dentine Permeability after Apicectomy and Surface Treatment with 9.6 µm TEA CO₂and Er:YAG Laser Irradiation

Abstract

Failure of apicectomies is generally attributed to dentine surface permeability as well as to the lack of an adequate marginal sealing of the retrofilling material, which allows the percolation of microorganisms and their products from the root canal system to the periodontal region, thus compromising periapical healing. The purpose of this study was to evaluate dentine and the marginal permeability after apicectomy and surface treatment with 9.6 micro m TEA CO(2) or Er:YAG 2.94 micro m laser irradiation. Sixty-five single rooted human endodontically treated teeth were divided into five experimental groups: group I (control), apicectomy with high speed bur; group II, similar procedure to that of group I, followed by dentinal surface treatment with 9.6 micro m CO(2) laser; group III, similar procedure to group I followed by dentinal surface treatment with Er:YAG laser 2.94 micro m; group IV, apicectomy and surface treatment with CO(2) 9.6 micro m laser; and group V, apicectomy and surface treatment with Er:YAG laser 2.94 micro m. The analysis of methylene blue dye infiltration through the dentinal surface and the retrofilling material demonstrated that the samples from the groups that were irradiated with the lasers showed significantly lower infiltration indexes than the ones from the control group. These results were compatible with the structural morphological changes evidenced through SEM analysis. Samples from groups II and IV (9.6 micro m CO(2)) showed clean smooth surfaces, fusion, and recrystallized dentine distributed homogeneously throughout the irradiated area sealing the dentinal tubules. Samples from groups III and V (Er:YAG 2.94 micro m) also presented clean surfaces, without smear layer, but roughly compatible to the ablationed dentine and without evidence of dentinal tubules. Through the conditions of this study, the Er:YAG 2.94 micro m and the 9.6 micro m CO(2) laser used for root canal resection and dentine surface treatment showed a reduction of permeability to methylene blue dye.

Analysis of the morphology and composition of tooth apices apicectomized using three different ablation techniques

“…Surfaces cut with burs were the smoothest and so exhibited the greatest dentin permeability, followed by those cut with the Er:YAG and CO 2 lasers. The latter resulted in the least dentin permeability as a result of the melting and recrystallization of the dentin, obliterating dentin tubules (9). With relation to the presence of failures at the interface between the dentin and the obturation material, the bur group had the lowest incidence and the smallest size failures, resulting in flatter surfaces and less gutta-percha displacement when compared with the other groups.…”

“…Root surfaces irradiated with CO 2 laser have craters presenting a carbonized superficial layer, forming a matrix similar to cementum and absence of dentin tubules (8). In addition, human teeth apicectomized using Er:YAG laser and CO 2 laser compared to burs had smoother surfaces and more homogeneous fusion and recrystallization, with occluded tubules and reduced permeability (9). The objective of this study was to investigate apicectomies performed using burs or laser technologies.…”

CO2 Laser: Evidence Based Applications in Dentistry

“…Since the 9.6micrometer CO2 laser wavelength is highly absorbed in appetite crystals, it presents a future potential for its applications in cavity preparation, apicectomies and other hard tissue procedures. In vitro study using Scanning Electron Microscopic (SEM) images reported cleaner dentinal surface with fusion and recrystallized dentine following apicectomy and root treatment with pulsed TEA 9.6micrometer CO2 laser (Gouw-Soares et al, 2004). Contrasting results were reported in a more recent SEM analysis study.…”

“…For example, Nd:YAG and Diode lasers are absorbed by dark pigments making them ideal for soft tissue procedures. Tissue component that maximally absorbs CO2 wavelength is water followed by apatite (Gouw-Soares et al, 2004). Because of this CO2 lasers have been proven to be the gold standard for intra-oral soft tissue applications for decades.…”

Lasers in Apicoectomy: A Brief Review

“…In an attempt to increase the successful rate of endodontic surgical procedures, Gouw-Soares et al 18 showed that…”