Buffer Capacity of Saliva as a Function of Time after Consumption of Sugary, Sugar-Free and Probiotic Chewing Gums

To determine the time required for pH buffering by saliva after use sugary(S), sugar-free (SF) and probiotic (P) chewing gums.Material and Methods:Saliva was collected from 12 volunteer dental students at UNESP São José dos Campos / SP, in order to determine salivary flow (SR) rate and initial buffering capacity (BC). Participants presenting BC>4.0 were invited to continue the research. Participants chewed different types of gum for 3 consecutive days, and saliva was collected at 0-1min, 1-5min, and 5-10min intervals. The time required to neutralize saliva pH after chewing the different types of gum was analyzed by RM ANOVA and Tukey's test (5%).Results:RM ANOVA revealed significant influence on the interaction effect (chewing gum and time) (statisticFdf(4.66)= 4.027, p = 0.0055 <0.05). According to TukeyÆs test, differences were observed in the following circumstances: for the 0-1 interval, BC of S differs from SF and P; BC of S differs from SF at 1-5 min and 5-10 min intervals; and, 0-1min interval differs from 1-5 min and 5-10 min intervals for both S and SF. Conclusion:Dentistry students showed no increased predispositionto dental caries with a specific type of chewing gum. Although time for pH recovery differed according to gum type, they were all above the critical range for enamel demineralization...

Intrapulpal temperature variation during bleaching with various activation mechanisms

OBJECTIVES: The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35 percent hydrogen peroxide using different sources of activation. MATERIAL AND METHODS: Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12): (G1) Control - Bleaching gel without light activation, (G2) Bleaching gel + halogen light, (G3) Bleaching gel + LED, (G4) Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (a=0.05). RESULTS: The mean intrapulpal temperature values (ºC) in the groups were: G1: 0.617 ± 0.41; G2: 1.800 ± 0.68; G3: 0.975 ± 0.51; and G4: 4.325 ± 1.09. The mean maximum temperature variation (MTV) values were: 1.5ºC (G1), 2.9ºC (G2), 1.7ºC (G3) and 6.9ºC (G4). When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05), but G2 and G4 presented significantly higher (p<0.05) intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05) from each other. CONCLUSIONS: The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.

Reparo de restaurações diretas: um recurso na clínica diária / Repair of direct restorations: a resource in the daily clinic

O objetivo deste trabalho foi avaliar a resistência à tração entre resinas de uso direto de três diferentes marcas comerciais, simulando reparos, utilizando ou não adesivo nesta interface. Para tanto foram confeccionadas 60 bases cônicas em resina composta (TPH) apresentando as seguintes dimensões: 5mm de comprimento, com uma base maior de 5mm e uma base menor de 3mm de diâmetro. Essas bases foram divididas aleatoriamente em 6 grupos. Sob estas bases foram aplicadas, com auxílio de uma matriz bi-partida de teflon, três resinas: TPH (Dentsply), InTen-S (Ivoclar), Filtek Supreme (3M-ESPE), com ou sem a utilização de um adesivo dentinário (Single Bond û 3M-ESPE), de maneira a obter amostras na forma de ampulheta. Após armazenamento destas amostras durante 7 dias à 37º C, estas foram submetidas ao ensaio de tração em uma máquina de ensaios universal com velocidade de 1,0 mm/ min e célula de carga de 500Kgf a qual carregou a amostra até que ocorresse sua fratura. Os dados obtidos (MPa) foram submetidos à Análise de Variância (ANOVA), e ao o teste de Tukey (5%). As médias e desvios padrão foram obtidos dos grupos sem e com adesivo, respectivamente: G1 - TPH 10,88±2,37, G2 - 17,59±3,42; G3 - Filtek 3,91±3,06, G4 - 14,02±4,34; G5 - Inten-S 5,32±1,30, G6 - 12,54±2,06. O teste estatístico de Tukey demonstrou que a utilização do adesivo levou a valores de tração estatisticamente maiores independentemente da marca comercial de resina composta, assim como a utilização da mesma resina da base, para o reparo.

This study evaluated the tensile bond strength between direct composite resins of three different brands, simulating repairs with or without utilization of adhesive at this interface. For that purpose, 60 tapered composite resin (TPH) bases were fabricated with the following dimensions: 5mm length, a larger base measuring 5mm in diameter and a smaller base with 3-mm diameter. These bases were randomly divided into 6 groups. Three resins were applied on these bases, with aid of a split Teflon matrix: TPH (Dentsply), InTen-S (Ivoclar), Filtek Supreme (3M-ESPE), with or without utilization of a dentin adhesive (Single Bond û 3M-ESPE), for achievement of hourglass-shaped specimens. After storage of specimens for 7 days at 37ºC, these were submitted to tensile testing in a universal testing machine EMIC û DL1000, at a crosshead speed of 1.0mm/min and a load cell of 500Kgf, which applied load on the specimen until occurrence of fracture. Data achieved (MPa) were submitted to Analysis of Variance (ANOVA) and to the Tukey test (5%). The means and standard deviations for groups with and without adhesive were as follows: G1 û TPH 10.88±2.37, G2 û 17.59±3.42; G3 û Filtek 3.91±3.06, G4 û 14.02±4.34; G5 û Inten-S 5.32±1.30, G6 û 12.54±2.06. The Tukey test demonstrated that utilization of the adhesive provided statistically higher tensile values, regardless of the composite resin brand, as well as repair with the same resin employed for the base.