Abstract: The erbium laser light has a great affinity to the water molecule, which is present in great quantity in biological hard tissues. The objective of this work is to identify chemical changes by infrared spectroscopy of irradiated dentin by an Er:YAG - 2.94μm laser. The irradiation was performed with fluences between 0.365 J/cm2 and 1.94 J/cm2. For the infrared analysis a Fourier transform infrared spectrometer was used. After the irradiation were observed: loss of water, alteration of the structure and composition of the collagen and increase of the OH- radical. These alterations can be identified by a decrease of the water and OH- band between 3800-2800 cm-1, bands ascribed to collagen structure between 1400-1100 cm-1. The results show that the erbium laser changes the structure and composition of the organic matrix, OHradical and the water composition in the irradiated dentin.

Palavras-Chave: dentin; bone tissues; teeth; erbium; lasers

BACHMANN, L.; DIEBOLDER, R.; HIBST, R.; ZEZELL, D.M. Changes in chemical composition and collagen structure of dentin tissue after erbium laser irradiation. Brazilian Dental Journal, v. 15, p. 78-78, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32734. Acesso em: $DATA.

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Abstract: This study investigated Ho:YLF (2,065 mm) effects on dental enamel with regards to the thermal variations in the pulp chamber during irradiation and resistance to demineralization. Twenty samples of bovine enamel were divided: 1) control- acidulated phosphate fluoride (APF) topic application followed by demineralization treatment with lactic acid; 2) Ho:YLF irradiation (100J/cm2) followed by APF and demineralization; 3) Ho:YLF irradiation (350J/cm2) followed by APF and demineralization; 4) Ho:YLF irradiation (450J/cm2) followed by APF and demineralization. All samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments. X-Ray fluorescence spectrochemical analysis showed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF (ANOVA, Tukey p<0,01). To evaluate the feasibility of this study for clinical purposes, surfaces morphology were analyzed. Modifications were characterized by melted and re-solidified regions of the enamel, which can changes its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm2 and 450 J/cm2 were also monitored in the pulp chamber in real time. Temperature increases were limited to 4,2° C.

Palavras-Chave: teeth; dentin; animals; cattle; enamels; laser radiation; holmium; chemical composition

EDUARDO, P.L.P.; BACHMANN, L.; SALVADOR, V.L.; ZEZELL, D.M. Chemical Modification of bovine dental enamel irradiated with holmiun laser. Brazilian Dental Journal, v. 15, p. 106-106, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32747. Acesso em: $DATA.

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Abstract: The aim of this study was to evaluate the effects of Er,Cr:YSGG laser irradiation on root dentin permeability. Twenty extracted single-rooted teeth were instrumented with K-files and divided in four groups, according to laser fluences: GI (non-irradiated), GII (12.5 mJ/pulse; 2.8 J/cm2), GIII (25 mJ/pulse; 8.5 J/cm2) and GIV (75 mJ/pulse; 16.98 J/cm2). Lased groups had an association of irrigating solution EDTA-T and Er,Cr:YSGG laser irradiation, which was performed at 20 Hz repetition rate without airwater spray, with four helicoidal movements during approximately 5 seconds. NDP associated with rhodamine B dye was used to evaluate dentin permeability. After the experimental period, the samples were transversely cut into six 2.0 mm thick slices for subsequent reading using the ImageLab software. The results showed that dentin permeability of root canals was decreased when exposed to Er,Cr:YSGG laser irradiation compared with non-irradiated samples, and this alteration was higher when higher fluences were applied. The cervical and middle thirds had permeability values statistically similar (p > 0.05) and significantly greater than the apical third. It can be concluded that the use of Er,Cr:YSGG laser irradiation at the utilized parameters decreases dentin permeability, favoring the root canal sealing.

Palavras-Chave: dentin; laser radiation; permeability

ANA, P.A.; ROCHA, R.M.M.; BLAY, A.; AUN, C.E.; LAGE-MARQUES, J.L.; ZEZELL, D.M. Effects of Er, Cr:YSGG Laser irradiation on endodontics system permeability. Brazilian Dental Journal, v. 15, p. 99-99, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32745. Acesso em: $DATA.

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Abstract: The aim of this study was to investigate the effects of low-intensity red laser radiation on the ultrastructure of dentine-pulp interface after conventionally prepared class I cavity preparation. Eight premolars indicated for extraction for orthodontic reasons from 2 patients were used. Class I cavities were prepared and the teeth were divided into two groups. The first group received a treatment with a GaAlAs laser, l= 660 nm, P= 30 mW and D= 2J/cm2. The laser tip was applied directly and perpendicularly into the cavity in only one sense. The teeth from the second group had their class I cavities prepared but they did not receive the laser therapy. All cavities were filled with composite resin. Twenty-eight days after the preparation, the teeth were extracted and processed for transmission electron microscopy analysis. Two sound teeth (healthy group) without any preparation were also examined. The first group presented odontoblastic processes in intimate contact with the extracellular matrix, while the collagen fibers appeared more aggregated and organized than those of the second group. These results were also observed in the healthy teeth. The results suggest that laser irradiation accelerates the recovery of the structures at the dentine-pulp interface involved during cavity preparation layer.

Palavras-Chave: teeth; dentin; oral cavity; lasers; radiation effects

GODOY, B.M.; ARANA-CHAVEZ, V.E.; BORTOLI GROTH, E.B.; RIBEIRO, M.S. Effects of low-intensity red laser radiation on the dentine-pulp interface after class I cavity preparation disfunction. Brazilian Dental Journal, v. 15, p. 86-87, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32758. Acesso em: $DATA.

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Abstract: The purpose of this study was to evaluate the temperature rising inside the pulpar cavity during the diode laser irradiation on the root surface. Twelve single root teeth were used and their mesial and distal surfaces were irradiated (808 nm, 400 m, 30 s), in a continuous mode (CW) and in an switched mode (SW) (10 Hz). The temperature rise was evaluated deppending with the power used (0.4 W to 2.2 W). The temperature was monitorated with a termopar (T) fixed inside de pulpar cavity during the irradiation. In a second step two parameters was used in a SW (10 Hz). The safety temperature was keep using the power: Group A - 0.9 W (mesial ) and Group B - 1.08 W (distal). The results showed the termal pulpar events (T) during the irradiation, based in an specific relation with the power (P), like T= -0.4+3.7P in a CW and T= -0.2+2P in a SW. The temperature rising during the irradiation was 3.4±0.4ºC on Group A and 4.0±1.0ºC on Group B. The irradiation mode and the power are much important to temperature rise inside the pulpar cavity and the 0.9 W and 1.08 W radiation on the root surfaces were safety.

Palavras-Chave: semiconductor diodes; laser radiation; dentin; temperature dependence; teeth

HAYPEK, P.; THEODORO, L.H.; BACHMANN, L.; EDUARDO, C.P.; SAMPAIO, J.E.C.; ZEZELL, D.M. Effects of the diode laser irradiation on root surfaces: thermal analysis. Brazilian Dental Journal, v. 15, p. 110-110, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32749. Acesso em: $DATA.

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Abstract: A great number of children suffer from traumatic injuries on the deciduous dentition. The darkening resulting from these injuries create an aesthetic probem in these children in the middle of their psychosocial development. The whitening technique might be a satisfactory aesthetic resolution, as well as non-invasive. The objectives of the present study were to evaluate "in vitro" and "in vivo" the teeth color variation and superficial temperature, obtained by the thermocatalytic technique used in devitalized human deciduous teeth, as well as evaluate "in vivo" the teeth color variation obtained by the whitening. The whitening agent was the hydrogen peroxide 35%,having as a variant the source of catalyzing energy- diode laser and the light curer. 21 deciduous teeth were utilized. The light curer group-11 teeth and the laser group, 10.The color evaluation was carried out by the spectrophotometer and VITA 3D scale. After statistic analysis, it can be concluded that the whitening was verified by both methods.The temperature variation was significantly higher in the light cure group than in the laser group.

Palavras-Chave: dentin; teeth; hydrogen peroxide; semiconductor diodes; bleaching

GONTIJO, I.T.; CIAMPONI, A.L.; ZEZELL, D.M.; NAVARRO, R.; RODRIGUES, W.; CIAMPONI, A.L. In vitro and in vivo evaluation of deciduos teeth withening technique: the diode laser and light cure. Brazilian Dental Journal, v. 15, p. 93-93, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32741. Acesso em: $DATA.

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Abstract: Applications of high intensity lasers in the enamel and dentine can produce adverse thermal effects into the pulp. Since the evaluation thermal effects into the intact pulp is not a solved problem, extracted teeth models have been used frequently. Current models, however, simulate only tooth thermal properties, not taking the remaining radiation in the pulp chamber into account. The aim of this study was to verify if the remaining radiation from neodymium and diode lasers that reach the pulp chamber, at the models using extracted bovine teeth, can causes local thermal effects. For this purpose, two models were developed using extracted bovine teeth with their pulp chambers filled with: water (model 1) and with an optical absorbent (model 2). Models were radiated with 1 W. The obtained results show that, for both lasers, the temperature rise in model 2 pulp chamber is: i) up to 11% higher than in the model 1 when the enamel is radiated and ii) up to 37% higher than in the model 1 when dentine is radiated (1 mm from the pulp). Thus, remaining radiation into the pulp is relevant for the above mentioned lasers and doses.

Palavras-Chave: biological radiation effects; dentin; dentistry; enamels; laser radiation; temperature dependence

FARHART, P.B.A.; TANJI, E.Y.; FARHAT, R.P.; ZEZELL, D.M.; MIYAKAWA, W.; NOGUEIRA, G.E.C. Model of thermal and optical effects in dental pulp during the neodymium and diode lasers irradiation. Brazilian Dental Journal, v. 15, p. 90-90, 2004. Special issue. Disponível em: http://repositorio.ipen.br/handle/123456789/32738. Acesso em: $DATA.

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