The influence of erbium:yttrium-aluminum-garnet laser ablation with variable pulse width on morphology and microleakage of composite restorations.

The objective of this study was to evaluate the influence of various pulse widths with different energy parameters of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mum) on the morphology and microleakage of cavities restored with composite resin. Identically sized class V cavities were prepared on the buccal surfaces of 54 bovine teeth by high-speed drill (n = 6, control, group 1) and prepared by Er:YAG laser (Fidelis 320A, Fotona, Slovenia) with irradiation parameters of 350 mJ/ 4 Hz or 400 mJ/2 Hz and pulse width: group 2, very short pulse (VSP); group 3, short pulse (SP); group 4, long pulse (LP); group 5, very long pulse (VLP). All cavities were filled with composite resin (Z-250-3 M), stored at 37 degrees C in distilled water, polished after 24 h, and thermally stressed (700 cycles/5-55 degrees C). The teeth were impermeabilized, immersed in 50% silver nitrate solution for 8 h, sectioned longitudinally, and exposed to Photoflood light for 10 min to reveal the stain. The leakage was evaluated under stereomicroscope by three different examiners, in a double-blind fashion, and scored (0-3). The results were analyzed by Kruskal-Wallis test (P > 0.05) and showed that there was no significant differences between the groups tested. Under scanning electron microscopy (SEM) the morphology of the cavities prepared by laser showed irregular enamel margins and dentin internal walls, and a more conservative pattern than that of conventional cavities. The different power settings and pulse widths of Er:YAG laser in cavity preparation had no influence on microleakage of composite resin restorations.

Comparative analysis of root surface smear layer removal by different etching modalities or erbium:yttrium-aluminum-garnet laser irradiation. A scanning electron microscopy study.

The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mum) irradiation on the removal of root surface smear layer of extracted human teeth and to compare its efficacy with that of citric acid, ethylenediamine tetra-acetic acid (EDTA), or a gel containing a mixture of tetracycline hydrochloride (HCl) and citric acid, using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control group), irrigated with 10 ml of physiologic saline solution; G2, conditioned with 24% citric acid gel; G3, conditioned with 24% EDTA gel; G4, conditioned with a 50% citric acid and tetracycline gel; G5, irradiated with Er:YAG laser (47 mJ/10 Hz/5.8 J/cm(2)/pulse); G6, irradiated with Er:YAG laser (83 mJ/10 Hz/10.3 J/cm(2)/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed between the Er:YAG laser groups and those undergoing the other treatment modalities. When the two Er:YAG laser groups were compared, the fluency of G6 was statistically more effective in smear layer removal than the one used in G5 (Mann-Whitney test, P < 0.01). Root surfaces irradiated by Er:YAG laser had more irregular contours than those treated by chemical agents. It can be concluded that all treatment modalities were effective in smear layer removal. The results of our study suggest that the Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of Er:YAG laser irradiation on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed.

Effect of Er:YAG and Diode lasers on the adhesion of blood components and on the morphology of irradiated root surfaces.

OBJECTIVE: The aim of this study was to evaluate in vitro, by scanning electron microscopy (SEM), the adhesion of blood components on root surfaces irradiated with Er:YAG (2.94 microm) and GaAlAs Diode (808 nm) lasers and the effects on the morphology of irradiated root surfaces. METHODS: One hundred samples of human teeth were obtained. They were previously planed and scaled with manual instruments and divided into five groups of 20 samples each: G1 (control group) - absence of treatment; G2--Er:YAG laser (7.6 J/cm2); G3--Er:YAG laser (12.9 J/cm2); G4--Diode laser (90 J/cm2) and G5--Diode laser (108 J/cm2). After these treatments, 10 samples of each group received a blood tissue but the remaining 10 did not. After laboratory treatments, the samples were obtained by SEM, the photomicrographs were analysed by the score of adhesion of blood components and the results were statistically analysed (Kruskall-Wallis and Mann-Whitney test). RESULTS: In relation to the adhesion of blood components, the study showed no significant differences between the control group and the groups treated with Er:YAG laser (p = 0.9633 and 0.6229). Diode laser radiation was less effective than control group and Er:YAG laser radiation (p < 0.01). CONCLUSIONS: None of the proposed treatments increased the adhesion of blood components in a significant way when compared to the control group. Although the Er:YAG laser did not interfere in the adhesion of blood components, it caused more changes on the root surface, whereas the Diode laser inhibited the adhesion.

The applications of diode and Er:YAG lasers in labial frenectomy in infant patients.

This paper describes a clinical case of labial frenectomy using different high power lasers: diode (810 nm) and Er:YAG (2940 nm). Considerations are made about specific indications, surgery techniques, and advantages of labial frenectomy using these laser wavelengths. The diode laser has high absorbance by pigmented tissues with hemoglobin, melanin, and collagen chromophores. For this reason, this wavelength is well indicated for surgery in soft tissue (vaporization, incision, coagulation, hemostasis). It is not properly absorbed, however, and should never be used in contact with hard tissues (bone). The Er:YAG laser has high absorbance to water and mineral apatite, making this wavelength useful and safe for the ablation of hard tissues. In the labial frenectomy clinical procedure, a combined technique is suggested: using the diode laser in soft tissues and the Er:YAG laser in periosteal bone tissues and for removal of final collagen fibers. It is important for the professional to understand the physical characteristics of the different laser wavelengths and their interaction with biological tissues to assure that they are used in a safe way, and that the benefits of this technology can be provided to infant patients.

Interação do laser de diodo de alta potência com a superfície radicular. Efeito na morfologia, na variação de temperatura e na adesão e proliferação de fibroblastos em cultura / Interaction between high power diode laser and dental root surface. Thermal, morphological and biocompatibility analysis

O objetivo do estudo foi analisar a interação entre o laser de diodo de alta potência e a superfície radicular através da análise de: variação de temperatura (Fase A), morfologia superficial das raízes dentárias (Fase B), adesão e a proliferação de fibroblastos cultivados sobre estas superfícies (Fase C). Vinte e um dentes unirradiculares foram utilizados nas 3 fases dos experimentos. Os grupos experimentais foram: Grupo controle - só recebeu o tratamento inicial de raspagem e alisamento radicular; Grupo INT - recebeu o mesmo tratamento do controle seguido de irradiação com o laser de diodo de alta potência, com comprimento de onda de 808 nm e fibra óptica de 400 μm de diâmetro, posicionada paralela à superfície radicular no parâmetro de 1,5 W (597,1 W/cm2 na ponta da fibra) durante 30 s no modo interrompido; e Grupo CW - onde foi usado o mesmo tratamento do grupo INT, porém com o laser no modo contínuo. Na fase A utilizaram-se termopares para monitorar a temperatura intrapulpar; na Fase B, microscopia eletrônica de varredura (MEV) das superfícies tratadas dos 3 grupos experimentais, e na Fase C, fibroblastos foram plaqueados sobre as superfícies tratadas e em eletromicrografias de varredura as células foram contadas em 24 (adesão), 48 e 72 h (proliferação) após o plaqueamento...

The effect of CO(2) laser irradiation on failed implant surfaces.

The aim of this investigation was to evaluate the cleaning effect of CO(2) on surface topography and composition of failed dental implant surfaces. Ten failed dental implants were retrieved from nine patients (mean age, 46.33 +/- 5.81 years) as a result of early or late failure. The implants were divided into two parts: one side of the implant was irradiated with a CO(2) laser (test side), while the other side did not receive irradiation (control side). The CO(2) laser was operated at 1.2 W in a continuous wave for 40 seconds (40 J energy). The handpiece of the CO(2) laser was kept at a distance of 30 mm from the implant surface, resulting in a spot area of 0.031415 cm (38.20 W/cm; 1559 J/cm) in scanning mode (cervical-apical). One unused dental implant was used as a negative control for both groups. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) for element analysis. SEM showed that the surface of the test sides consisted of different degrees of organic residues, appearing mainly as dark stains similar to those observed on the control sides. None of the test surfaces presented alterations such as crater-like alterations, lava-like layers, or melting compared with the nonirradiated surfaces. Foreign elements such as carbon, oxygen, sodium, calcium, and aluminum were detected on both sides. These results suggest that CO(2) laser irradiation does not modify the implant surface, although the cleaning effect was not satisfactory.

Cirurgia pré-potética utilizando laser de diodo associada a reembasamento com condicionador de tecidos: relato de caso clínico / Pre-prosthetic surgery using diode laser associated with a rebasing with tissue conditioners: a case report

A necessidade de remoção de tecidos hipertrofiados antes da confecção de próteses totais é ocorrência comum ma prática clínica. A utilização do laser para esse tipo de cirurgia de tecidos moles tem demonstrado melhores resultados que as técnicas convencionais. Quando se associa a essa técnica o recurso do reembasamento com condicionadores de tecido, opaciente poderá usar sua prótese durante o período de cicatrização. Além desse conforto, a prótese reembasada servirá como guia para uma reparação morfologicamente correta. O caso clínico relatado é de uma paciente portadora de próteses totais há 30 anos, que, por instabilidade, acabaram por causar-lhe uma hipertrofia na região anterior da mandíbula. Foi feita a remoção e, em seguida, o reembasamento. Verificou-se um pós-operatório com excelente aparência clínica e recuperação muito mais rápida e indolor, permitindo que apema s22 dias depois do ato cirúrgico já se pudesse iniciar os procedimentos de confecção de novas próteses da paciente

Effect of ER:YAG and diode laser irradiation on the root surface: morphological and thermal analysis.

BACKGROUND: The aim of the present study was to compare the effects of Er:YAG and diode laser treatments of the root surface on intrapulpal temperature after scaling and root planing with hand instruments. METHODS: Fifteen extracted single-rooted teeth were scaled and root planed with hand instruments. The teeth were divided into 3 groups of 5 each and irradiated on their buccal and lingual surfaces: group A: Er:YAG laser, 2.94 microm/100 mJ/10 Hz/30 seconds; group B: diode laser, 810 nm/1.0 W/0.05 ms/30 seconds; group C: diode laser, 810 nm/1.4 W/0.05 ms/30 seconds. The temperature was monitored by means of a type T thermocouple (copper-constantan) positioned in the pulp chamber to assess pulpal temperature during and before irradiation. Afterwards, the specimens were longitudinally sectioned, and the buccal and lingual surfaces of each root were analyzed by scanning electron microscopy. RESULTS: In the Er:YAG laser group, the thermal analysis revealed an average temperature of -2.2 +/- 1.5 degrees C, while in the diode laser groups, temperatures were 1.6 +/- 0.8 degrees C at 1.0 W and 3.3 +/- 1.0 degrees C at 1.4 W. Electronic micrographs revealed that there were no significant morphological changes, such as charring, melting, or fusion, in any group, although the specimens were found to be more irregular in the Er:YAG laser group. CONCLUSIONS: The application of Er:YAG and diode lasers at the utilized parameters did not induce high pulpal temperatures. Root surface irregularities were more pronounced after irradiation with an Er:YAG laser than with a diode laser.

Morphologic analysis, by means of scanning electron microscopy, of the effect of Er: YAG laser on root surfaces submitted to scaling and root planing

O objetivo do presente estudo foi analisar morfologicamente, através de microscopia eletrônica de varredura, os efeitos do laser de Er: YAG no tratamento de superfície radiculares submetidas à raspagem e aplainamento radicular com instrumentos manuais. Foram utilizados 18 espécimes(n=18) de superfícies radiculares que após ser submetidos à raspagem e aplainamento radicular foram divididos em 3 grupos (n=6). O grupo controle (G1) näo sofreu nenhum tratamento; Grupo 2 (G2) foi irradiado com laser de Er: YAG (2,94 µm) 47mJ/10Hz, focalizado,com refrigeraçäo à água durante 15s e fluência de pulso de 0,57 J/cm²; Grupo 3 (G3) foi irradiado com laser de Er: YAG (2,94 µm), 83 mJ/10Hz, focalizado, com refrigeraçäo à agua durante 15s e fluência de pulso de 1,03 J/cm². Através da análise dos resultados podemos concluir que o laser de Er: YAG nos parâmetros utilizados no G3 promove a remoçäo de smear layer da superfície radicular e exposiçäo dos túbulos dentinários, porém o laser promove aspecto irregular na superfície, apesar de näo demonstrar crateras, fendas, fraturas e carbonizaçäo, necessitando de estudos que demonstrem a biocompatibilidade desta superfície no processo de reparo periodontal

Morphologic analysis, by means of scanning electron microscopy, of the effect of Er: YAG laser on root surfaces submitted to scaling and root planing.

The purpose of this study was to morphologically evaluate, by means of scanning electron microscopy, the effects of Er:YAG laser on the treatment of root surfaces submitted to scaling and root planing with conventional periodontal instruments. Eighteen root surfaces (n = 18), which had been previously scaled and planed, were assigned to 3 groups (n = 6). The control Group (G1) received no further treatment; Group 2 (G2) was irradiated with Er:YAG laser (2.94 mum), with 47 mJ/10 Hz, in a focused mode with air/water spray during 15 s and with 0.57 J/cm of fluency per pulse; Group 3 (G 3) was irradiated with Er:YAG laser (2.94 mum), with 83 mJ/10 Hz, in a focused mode with air/water spray during 15 s and with 1.03 J/cm2 of fluency per pulse. We concluded that the parameters adopted for Group 3 removed the smear layer from the root surface, exposing the dentinal tubules. Although no fissures, cracks or carbonized areas were observed, an irregular surface was produced by Er:YAG laser irradiation. Thus, the biocompatibility of the irradiated root surface, within the periodontal healing process, must be assessed.