Comparative study of dentine permeability after apicectomy and surface treatment with 9.6 microm TEA CO2 and Er:YAG laser irradiation.

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.

Scanning electron microscopy (SEM) and optical microscopy: effects of Er:YAG and Nd:YAG lasers on apical seals after apicoectomy and retrofill.

OBJECTIVE: This study evaluated the dentinal and marginal permeability of the cut surface after apicoectomy, treatment and retrocavity preparation with Er:YAG and Nd:YAG lasers. Furthermore, scanning electron microscopy (SEM) analysed the morphological alteration of dentin caused by laser irradiation through an optical fiber. BACKGROUND DATA: Numerous studies have shown the beneficial effects of laser treatment upon sealing dental apex, avoiding the changes of organic fluids, microorganisms and their by-products between the root canal system and periapex. MATERIALS AND METHODS: Twenty-four extracted and endodontically treated teeth were divided into three groups: GI, apices were resected with Er:YAG laser (350 mJ; 4 Hz) treatment of cut dentinal surface and retrocavity were lased with this same laser (120 mJ; 4 Hz; bur 2051) using the optical fiber 50/10; GII, apicoectomy was performed similar to GI, however the cut dentinal surface was treated with Nd:YAG laser through optical fiber, as well as the retrocavity preparation (100 mJ; 15 Hz; 1.5 W); and GIII (control group), high speed burs were used. RESULTS: Analysis of methylene blue dye penetration into dentin demonstrated that the specimens of the groups irradiated with laser showed to have lower infiltration indices than the control group. These results were compatible with structural and morphological injuries, evidenced by SEM. CONCLUSION: Under the conditions of the present study, apicoectomy using Er:YAG laser, followed by dentinal surface irradiation and retrocavity preparation with Nd:YAG laser, showed to be an alternative clinical tool able to reduce the dentinal permeability.

The use of Er:YAG, Nd:YAG and Ga-Al-As lasers in periapical surgery: a 3-year clinical study.

OBJECTIVES: In an attempt to increase the successful rate of endodontic surgical procedures this study proposes the use of an association of three lasers in apicectomy: Er:YAG laser, (wavelength 2.94 microm pulse mode), Nd:YAG laser (wavelength 1.064 microm, pulse mode), and Ga-Al-As laser, (wavelength of 790 nm, continuous wave). BACKGROUND DATA: Previous studies have shown the low success rate of apicectomy by conventional methods due to the presence of remaining bacteria in the surgical site. METHODS: The Er:YAG laser was used to perform osteotomy and root resection without vibration, discomfort, less contamination of the surgical site, and no smear-layer on the dentine surface. The Nd:YAG laser irradiation through a fiber performed sealing of the dentinal tubules and bacterial reduction of the cavity bone. In addition, the improvement of healing and better post-operative achieved with the Ga-Al-As laser encourages the use of those lasers in periapical surgeries. RESULTS: Three years follow-up examination of the clinical case showed radiographically significant decrease of the radiolucent periapical area and no clinical signs and symptoms. CONCLUSION: The outcome of this clinical case indicates that the use of those lasers could be considered an alternative, suitable, and useful method to perform an apicectomy.

The bactericidal effect of Ho:YAG laser irradiation within contaminated root dentinal samples.

OBJECTIVE: This in vitro study investigates the bactericidal effect of pulsed Ho:YAG laser irradiation in the depth of contaminated dentin specimens. BACKGROUND DATA: Previous studies have shown the effectiveness of laser irradiation in bacterial reduction of infected root canal. METHODS: Root dentin of bovine teeth were sliced longitudinally in 180 samples of 100 microm, 300 microm, and 500 microm thickness, sterilized, dried, and inoculated on one side, with 1 microL of Enterococcus faecalis suspension. The opposite side's were irradiated four times for 5 seconds each with Ho:YAG laser irradiation, a wavelength of 2.10 microm, using four different energy settings: 1 W/5 Hz; 1 W/10 Hz; 1.5 W/5 Hz, and 2.0 W/5 Hz through a 320-microm quartz fiber at an angle of approximately 5 degrees. In addition, two control groups were investigated, the first was inoculated and not submitted to any treatment, the second was inoculated and treated with NaOCl and H2O2. The remaining bacteria from each dentin sample in a transport media were removed by vibration, serially diluted, and plated out on culture dishes selective for Enterococcus faecalis. RESULTS: When compared with the untreated control group or even with the group treated with NaOCl plus H2O2, counting of colonies forming units (CFU) from the laser-treated samples revealed a high significant bacterial elimination with a maximum of 98.46% and a minimum of 83.65%. CONCLUSIONS: Our findings demonstrate a significant decrease of the bacterial population in depth, suggesting that the Ho:YAG laser irradiation could be effective to eliminate the microorganisms harbored within dentin or contaminated canals.