ANDREA ANTUNES PEREIRA

ANDREA ANTUNES PEREIRA

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Effect of a diode laser irradiation in root canals contamined with Enterococcus faecalis
2002 - RADAELLI, C.R. de M.; ANTUNES, A.; CAI, S.; ZEZELL, D.M.; GOUW-SOARES, S.
High success rates were achieved in conventional endodontic treatment of vital pulp teelh. However, in non-vital pulp a decrease of success occurs due to difficulties to achieve a complete disinfection of root canal system. Some bacteria, such as Enterococcus faecalis, are frequently found in endodontic treatment failure due to their high resistance to the usual process of canal shaping and cleaning. The purpose of this work was to evaluate the effectiveness of a diode laser irradiation in bacterial reduction of contaminated canals as well as to analyze the effect of the laser irradiation associated with the use of calcium hydroxide paste. Eighty two root canals infected with Enterococcus faecalis suspension (1x10(6) CFU/ml) were irradiated with a high power diode laser (810nm, Opus 10- Sharplan - Israel) with two different parameters: 2.5W and 3 W (cw), using a 360 μm fiber at an angle of approximately 5 degrees to the dentine surface during 5 seconds in 5 applications, within 20 seconds intervals between. Temperature was monitored at apex using a K-pipe thermocouple. Maximum temperature was 7.45ºC. After these proceedings specimens were vortexed in peptone water and dilutions performed. Aliquots were plated on m-Enterococcus agar. Colonies Forming Units (CFU) of all groups was counted. Statistically the results showed a significant reduction of bacteria on all groups after laser irradiation. A high reduction rate was achieved: 98.5% immediately after laser irradiation; 48 hours after, the reduction rate was 96.73% and finally a 100% reduction was achieved with the association of laser irradiation and calcium hydroxide paste. These high rates of bacteria reduction were achieved using the parameter of 3W (cw), 4.24 KW/cm2. The use of high power diode laser 810nm is highly efficient and suitable to reduce Enterococcus faecalis in infected root canals.
Examination of dental hard tissues after short pulse Nd:YAG laser irradiation
2002 - ANTUNES, A.; VIANNA, S.S.; GOMES, A.S.L.; ROSSI, W. de; ZEZELL, D.M.
In the course of high intensity laser irradiation, expressive chemical and physical alteration may be induced in the irradiated dental tissues. We used short pulse Nd:YAG laser, with which damage in the tissue is reduced and thermal load can be better controlled. The use of nano and picosecond pulselengh also assures better accuracy in affected zone as well a smaller deepness. In one of the experiments, specimens were irradiated with different energy densities in a unique track of the laser beam on the enamel surface. Laser parameters used were: pulse width 6ns, energy densities from 10J/cm2 to 40J/cm2 and focused beam diameter of 0.1cm. In this case, the area of affected zone was 3 times higher than expected. In other experiment, bursts of shorter laser pulse width were used. In this case the laser emissin was formed by bursts composed of a train of 10 pulses with 100 ns of pulse width each. Energy densities from 10J/cm2 to 22.5J/cm2 and a focused beam diameter of 0.06cm were used. Heat affected zone was determined by Scanning Electron Microscopy, which showed a direct relationship between energy employed and morphological changes and as a result of dental tissue damage dimension.
Relationship between mineral composition and hardness of the human dental treated with short pulsed Nd:YAG laser in caries prevention
2001 - ANTUNES, A.; ROSSI, W. de; SALVADOR, V.; ZEZELL, D.M.
Various laser systems have been used in treatment of hard tissue with efficiency and safety. The action of the Nd:YAG laser in caries prevention has been reported for many research groups. Caries is a bacterial disease that affects a significant part of world population, causes minerals reduction and may lead to a total loss of the dental tissue. The aim of this study was to evaluate the use of short pulses Nd:YAG laser in caries prevention. The dependency between physico-chemical parameters like hardness and the mineral composition of dental enamel is outlined. Thirty human enamel samples were divided into two groups. The laser used emits radiation wavelength of 1.064 nm, energy of 73 mJ per pulse and 10 ns of pulse width. X-Ray Fluorescence, SEM and Vickers microhardness techniques were used. Obtained results are consistent with other studies and indicated greater Ca/P ratio in lased groups in comparison to the unlased group. The present study suggests that the use of the Q-Switched- d:YAG laser in enamel surfaces contributes to increase the hardness and decrease the mineral loss by bacterial acid attack.
Monitoramento da variacao da temperatura na desinfeccao intracanal com laser de diodo
2002 - RADAELLI, C.M.; PEREIRA, A.A.; ZEZELL, D.M.; SOARES, S.C.G.
Metodos de aplicacao de fluor, consequencias na inibicao da carie e discussao de sua funcao bioquimica no tratamento de amostras de esmalte dental irradiadas com laser
2002 - PEREIRA, A.A.; ROSSI, W.; ZEZELL, D.M.
Estudo in vitro de parametros seguros de irradiacao do laser de diodo de alta intensidade no tratamento de condutos radiculares
2002 - RADAELLI, C.A.R.M.; PEREIRA, A.A.; CAI, S.; ZEZELL, D.M.; SOARES, S.C.G.
Short pulse Nd:YAG laser in dental enamel surface: spectroscopic analysis
2002 - PEREIRA, A.A.; VIANNA, S.S.; GOMES, A.S.L.; ROSSI, W.; ZEZELL, D.M.
Atuacao do laser de Neodimio, operando em regime 'Modo Normal' e 'Q-switching', na superficie de esmalte dental: um estudo comparativo
2001 - PEREIRA, A.A.; ROSSI, W.; ZEZELL, D.M.
Analise da concentracao de fluor em amostra de esmalte dental irradiada com pulso curto de laser de Nd:YAG
2001 - PEREIRA, A.A.; ROSSI, W.; ZEZELL, D.M.
Analise das alteracoes nas propriedades morfologicas na superficie de esmalte dental irradiado com laser de neodimio para prevencao de caries
2000 - PEREIRA, A.A.; BACHMANN, L.; ROSSI, W.; ZEZELL, D.M.