ABSTRACT
Objective: The objective of the present study was to investigate the thermal effects of Er,Cr:YSGG laser irradiation (1.5W/20Hz) on yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP). Material and Method: Fifteen disks of Y-TZP (AS Technology TitaniumFIX, São José dos Campos, Brazil) with 5 mm diameter and 3 mm high standardized with CAD-CAM were used. The Y-TZP disks were randomized in three groups (n=5): Y-TZP-G1 = control (no laser treatment); Y-TZP-G2 = Y-TZP + Er,Cr:YSGG laser (air-water cooling proportion 80%/25%); Y-TZP-G3 = Y-TZP + Er,Cr:YSGG laser (air-water cooling proportion 80%/0%). A thermopar (SmartMether, Novus, Porto Alegre, RS, Brazil) was attached to a digital thermometer (SmartMether, Novus, Porto Alegre, RS, Brazil) fixed to the opposite irradiated surface. The temperature gradients (∆T) were calculated (∆T = Final Temperature - Initial Temperature) for each group. Values were statistically analyzed by one-way ANOVA at the 95% confidence level and compared by Tukey post-hoc test (α=0.05) for each material. One sample of each group was analyzed by confocal white light microscopy. Result: The ANOVA test showed significant differences for the factor "laser" (p<.001). The temperature gradients (∆T value) showed the following results: Y-TZP-G1 = 0 ºC; Y-TZP-G2 = -1.4 ºC and Y-TZP-G3 = 21.4 ºC. The ∆T values (ºC) of the non-refrigerated group were higher than the refrigerated group. The roughness value (Ra) ranged from 4.50 to -33.65 µm. Conclusion: The water refrigeration for Er,Cr:YSGG irradiation is essential to avoid thermal increase in the Y-TZP.
Objetivo: O objetivo do presente estudo foi investigar os efeitos térmicos do laser de Er,Cr:YSGG (1,5W/20Hz) em zircônia tetragonal policristalina estabilizada com ítrio (Y-TZP). Material e Método: Quinze discos de Y-TZP (AS Technology Titanium FIX, São José dos Campos, Brasil) com 5 mm de diâmetro e 3 mm de altura padronizados com CAD-CAM (computer-aided design e computer-aided manufacturing) foram usados. Os discos de Y-TZP foram randomicamente distribuídos em três grupos (n=5): Y-TZP-G1 = controle (sem irradiação); Y-TZP-G2 = Y-TZP + Er,Cr:YSGG (proporção resfriamento ar-água 80%/25%); Y-TZP-G3 = Y-TZP + Er,Cr:YSGG (proporção resfriamento ar-água 80%/0%). Um termopar (SmartMether, Novus, Porto Alegre, RS, Brasil) acoplado a um termômetro digital (SmartMether, Novus, Porto Alegre, RS, Brasil) foi fixado na face oposta à superfície irradiada. Os gradientes de temperatura ∆T foram calculados (∆T = Temperatura final - Temperatura inicial) para cada grupo. Os valores foram analisados estatisticamente por one-way ANOVA com 95% de confiança e comparados pelo teste Tukey (α=0,05). Uma amostra de cada grupo foi analisada por microscopia confocal de luz branca. Resultado: O: O teste ANOVA mostrou diferenças significativas para o fator "laser" (p< 0,001). Os gradientes de temperatura (valores de ∆T) apresentaram os seguintes resultados: Y-TZP-G1 = 0 ºC; Y-TZP-G2 = -1,4 ºC e Y-TZP-G3= 21,4 ºC. O valor de ∆T (ºC) do grupo sem refrigeração foi maior do que o grupo refrigerado. Os valores de rugosidade (Ra) variaram de 4,50 até -33,65 µm. Conclusão: A refrigeração com água para a irradiação do laser de Er,Cr:YSGG é essencial para evitar o aumento de temperatura de Y-TZP.
Subject(s)
Temperature , Ceramics , Analysis of Variance , Microscopy, Confocal , Dental Implantation , Lasers , Zirconium , Computer-Aided DesignABSTRACT
The use of autogenous bone grafts is considered to be the best choice for reconstructive surgery. In the periodontal literature, the utilization of osseous coagulum was suggested by the end of the sixties. The purpose of this study is to consider the use of bone collectors (bone traps) as an alternative method for obtaining material to fill small bone imperfections, such as fenestrations and dehiscences. Thirty samples were obtained from bone drilling during fixture installation in patients (13 men and 17 women, with an average age of 54 years) requiring treatment at the Department of Periodontology and Implant Dentistry, University of Santo Amaro. These samples were fixed in 10 percent neutral formaldehyde for 24 hours and subjected to histological preparation, in order to evaluate the presence of viable osteoblasts. In addition, the material was placed in a fluid thioglycolate medium and incubated for 24 hours at 36 ± 1°C in aerobiosis and anaerobiosis. Bacterial growth evaluation was made by using six different culture media (MacConkey agar, blood agar base, mannitol salt agar, Anaerokit LTD medium, Anaerokit LTD - bile medium, Anaerinsol). The results show that, if proper care is taken to prevent saliva contamination during the surgical procedure, this method of collecting autogenous bone may be useful in situations where small amounts of bone are required
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Bone Regeneration , Bone Transplantation , Dental ImplantsABSTRACT
Os autores visam através da utilizaçäo de enxerto ósseo homógeno, membrana reabsorvível e splintagem rígida dos dentes, obter uma regeneraçäo dos tecidos de suporte do elemento dental. O caso clínico teve acompamhamento durante 18 meses por meio de exame clínico, sondagem e radiografias