One-year clinical results of Er,Cr:YSGG laser application in addition to scaling and root planing in patients with early to moderate periodontitis.

In 30 patients with periodontitis, a total of 278 teeth exhibiting bleeding on probing, subgingival calculus, and a probing depth between 3-6 mm were examined. For each participant, two treatment types were alternatively applied on the contralateral quadrants: scaling and root planing (SRP) as control, and SRP followed by Er,Cr:YSGG laser application (SRP+laser), as a test method. Five clinical parameters: plaque level, bleeding on probing, probing depth, gingival recession and clinical attachment level were examined at baseline and at 2, 3, 6, 12 months after treatment. Of the total of 1,668 sites examined in all patients, 1,088 sites were found with a probing depth of 3-6 mm. In these sites, differences in clinical parameters between SRP and SRP+laser-treated quadrants were analyzed, assuming the level of p < 0.05 as significant. After 2 months from baseline, the mean probing depth reduction and the clinical attachment level gain were significantly greater in SRP+laser than in SRP quadrants, and remained so throughout the study (p < 0.001). A marked reduction of the bleeding scores occurred in all examined sites, irrespective of the treatment method. However, after 12 months, significantly less teeth exhibited bleeding on probing in SRP+laser quadrants than in SRP quadrants (p < 0.001). The mean plaque and gingival recession levels did not differ between the SRP and SRP+laser quadrants neither before nor after the treatment. The periodontal procedures either using Er,Cr:YSGG laser after SRP or SRP alone, lead to significant improvements in all clinical parameters investigated. However, laser application, as an adjunct to SRP, appeared to be more advantageous.

Efficacy of ultrasonic versus laser-activated irrigation to remove artificially placed dentin debris plugs.

INTRODUCTION: The study assessed the efficacy of laser activated irrigation (LAI) with Erbium: Yttrium Aluminum Garnet (Er:YAG) and Erbium Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) wavelengths as compared with passive ultrasonic irrigation (PUI). Previously proposed irrigation times were used for LAI (4x 5 seconds) and the intermittent flush technique (3x 20 seconds). METHODS: We used a split root model with an artificial root canal wall groove. Roots were prepared to an apical size # 40 with ProFiles 0.06 (Dentsply Maillefer, Baillaigues, Switzerland). Five groups of 20 straight canine roots were evaluated as follows: Group 1: hand irrigation for 20 s with 2.5% NaOCl (CI); Group 2: PUI performed once for 20 s with the #20 Irrisafe (Satelec Acteon group, Merignac, France) (PUI 1); Group 3: PUI for 3x 20 s with the Irrisafe (PUI 2); Group 4: LAI with the Er,Cr:YSGG laser and Z2 (200 microm) Endolase tip (Biolase, San Clemente, USA) at 75 mJ for 4x 5 s (LAI 1); Group 5: LAI with the Er:YAG laser (HoYa Versawave, Cortaboeuf, France) and a 200 mum endodontic fiber at 75 mJ for 4x 5 s (LAI 2). Images from the groove were taken before and after irrigation. The quantity of dentin debris in the groove after the experimental protocols was evaluated. RESULTS: Statistically significant differences (p < 0.05) were found between CI and all other groups and between PUI 1 and the other groups. CONCLUSION: LAI techniques using erbium lasers (Er:YAG or Er,Cr:YSGG) for 20 seconds (4x 5 seconds) are as efficient as PUI with the intermittent flush technique (3x 20 seconds).

The use of the erbium, chromium:yttrium-scandium-gallium-garnet laser in endodontic treatment: the results of an in vitro study.

BACKGROUND: The use of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser has become accepted in the field of cavity preparation. The development of miniaturized and flexible fiber tips has allowed this device to be used in endodontics. The authors conducted an in vitro study to assess the effects of Er,Cr:YSGG laser irradiation on root canals. METHODS: The authors inoculated root canals with two bacteria, laser irradiated them at two power settings and subjected them to a quantitative microbiological evaluation. They used scanning electron microscopy (SEM) to assess morphological changes in endodontically processed and laser-irradiated root canal walls. They measured temperature increases on the root surface to determine possible thermal side effects. RESULTS: The bacteriological evaluation revealed a disinfecting effect in the root dentin samples that was dependent on the output power but not specific for the bacterial species investigated. SEM showed the removal of the smear layer from the root canal walls and the exposure of dentinal tubules. The temperature rise during irradiation was moderate when standardized power settings were used. CONCLUSIONS: The Er,Cr:YSGG laser can be used to eliminate bacteria in root canals. It also effectively removes smear layer and debris from the canal wall. CLINICAL IMPLICATIONS: Practitioners can use the Er,Cr:YSGG laser to prepare root canals for endodontic therapy.

Innovative wavelengths in endodontic treatment.

BACKGROUND AND OBJECTIVES: The sanitation of the root canal system and the adjacent dentin has always been a key requirement for successful endodontics. In recent years, various laser systems have provided a major contribution to this aim, namely the Nd:YAG-, the 810 nm Diode-, the Er:YAG-, and the Er,Cr:YSGG laser. Numerous studies could prove their efficiency within the endodontic procedure. Recently, two new wavelengths have been introduced to the field of oral laser applications: The KTP laser emitting at 532 nm and the 980 nm diode laser. The present in vitro investigation was performed to evaluate the effects of these laser systems focusing on their antibacterial effect in deep layers of dentin and their impact on the root canal dentin. STUDY DESIGN/MATERIALS AND METHODS: Two-hundred slices of root dentin with a thickness of 1 mm were obtained by longitudinal cuts of freshly extracted human premolars. The samples were steam sterilized and subsequently inoculated with a suspension of either Escherichia coli or Enterococcus faecalis. After the incubation, the samples were randomly assigned to the two different laser systems tested. Each laser group consisted of two different operational settings and a control. The dentinal samples underwent "indirect" laser irradiation through the dentin from the bacteria-free side and were then subjected to a classical quantitative microbiologic evaluation. To assess the temperature increase during the irradiation procedure, additional measurements were carried out using a thermocouple. To assess the impacts on the root canal walls, 20 additional samples underwent laser irradiation at two different settings and were subjected to scanning electron microscopy. RESULTS: Microbiology indicated that both laser systems were capable of significant reductions in both test strains. At an effective output power of 1 W, E. coli was reduced by at least 3 log steps in most of the samples by the tested wavelengths, with the best results for the KTP laser showing complete eradication of E. coli in 75% of the samples. E. faecalis, a stubborn invader of the root canal, showed minor changes in bacterial count at 1 W. Using the higher setting of 1.5 W, significant reductions of E. coli were again observed with both laser systems, where the lasers were capable of complete eradication of E. faecalis to a significant extent. There was no significant relation between the temperature increase and the bactericidal effect. CONCLUSIONS: The present study demonstrates that both wavelengths investigated could be suitable for the disinfection of even the deeper layers of dentin and equal the results achieved by established wavelengths in state-of-the-art endodontics.

The Er:YAG laser in endodontics: results of an in vitro study.

BACKGROUND AND OBJECTIVE: Until recently, the main field of Er:YAG laser application was the removal of dental hard substances within the scope of cavity preparation. Nowadays, several new delivery-systems are available, permitting the application of the Er:YAG laser in endodontics. The aim of the present study was to assess the effects of Er:YAG laser irradiation on root canals in vitro. STUDY DESIGN/MATERIALS AND METHODS: For this purpose, 220 extracted human teeth were endodontically processed and subsequently irradiated at different settings using an Er:YAG laser imitating in vivo irradiation procedures. The teeth were then subdivided into three groups and subjected to bacteriological evaluations, scanning electron microscopy, and temperature measurements. RESULTS: The bacteriological evaluation revealed a decisive bactericidal effect of the Er:YAG laser in the root canal. The bactericidal effect was dependent on the applied output power and specific for the different species of bacteria investigated. Scanning electron microscopy showed discrete removal of dentine from the root canal walls. The temperature rise during irradiation was moderate when standardized power settings were used. CONCLUSION: The investigations indicate that the Er:YAG laser is a suitable tool for the elimination of bacteria in root canals under in vitro conditions.