Neste estudo avaliou-se o efeito de diferentes protetores de superfície na liberação de flúor (LF) e na resistência à tração diametral (TD) de dois cimentos de ionômero de vidro (CIV) convencionais restauradores, Chemfil e Chemflex (Dentsply). Manipulou-se os cimentos segundo as recomendações do fabricante, os espécimes confeccionados foram divididos em cinco grupos: grupo1 sem protetor (controle); grupo2 vaselina sólida; grupo3 verniz (Cavitine, S.S.White); grupo4 verniz fluoretado (Duraflur, Denstply); grupo5 adesivo (Magic Bond, Vigodent). Confeccionou-se para o teste de LF 40 espécimes para cada CIV, com dimensões de 4 mm de diâmetro por 6 mm de comprimento, divididos aleatoriamente entre os grupos e estocados individualmente em potes plásticos contendo 5 ml de água deionizada. Registrou-se o nível de fluoreto no período de 04 horas, 24 horas, 03 dias, 07 dias e 14 dias após a confecção, em um analisador Expandable Íon Analyser EA 960, sendo os resultados calculados em &#956;gF/ cm2. Confeccionou-se para o ensaio de TD 120 espécimes para cada CIV, com dimensões de 4 mm de diâmetro por 6 mm de comprimento, divididos aleatoriamente entre os grupos. Realizou-se ensaios mecânicos, com 1 dia e 14 dias após a confecção e estocagem individual dos espécimes em potes plásticos contendo 5 ml de água deionizada, em uma máquina universal de ensaios EMIC DL 500 MF, realizou-se um terceiro teste após 14 dias de ciclos de des-remineralização. Tratou-se estatisticamente os dados obtidos por ANOVA e por Student Newman-Keuls (p<0,05). No teste de LF os resultados demonstraram que o Chemfil liberou uma quantidade significantemente maior de flúor do que o Chemflex. Durante o período do teste a vaselina e o verniz tiveram um comportamento semelhante, mostrando uma menor LF do que o grupo controle nas primeiras 4 horas, com uma maior liberação na análise seguinte (24 horas). Os espécimes protegidos com vaselina e verniz, tiveram uma liberação de flúor semelhante ao grupo controle nos períodos de 3, 7 e 14 dias. O verniz fluoretado mostrou uma forte influência nas primeiras 24 horas. A partir da terceira análise observou-se uma maior liberação de flúor para o Chemfil em comparação com o Chemflex. Em relação ao emprego de um protetor superficial resinoso, encontrou-se tanto para Chemfil quanto para o Chemflex uma redução drástica na liberação de fluoreto, em todos os tempos analisados. No ensaio de TD o Chemfil não mostrou diferença estatisticamente significante quando os resultados de TD do seu grupo controle foram avaliados nos diferentes ensaios (24 horas, 14 dias e des-re), o mesmo acontecendo com o Chemflex. Ao se avaliar a influência dos diferentes protetores de superfície nos CIVs utilizados no presente trabalho observou-se que, para o Chemfil os protetores de superfície tiveram pouca influência no comportamento do material, se comportando na maioria das vezes de forma similar ao grupo controle. Em contrapartida, para o material Chemflex a utilização de um protetor de superfície, como o verniz fluoretado e o adesivo, permitiu maiores valores de resistência à TD. Conclui-se que quando se objetiva o uso do CIV por um curto período o Chemfil sem protetor parece ser o mais indicado, porém se o uso do CIV for por um longo período o Chemflex com a proteção do verniz fluoretado é o mais indicado. / This study evaluated the effect of different protective coatings on the fluoride release (FR) and on the diametral tensile strength (DTS) of two conventional restorative glass ionomer cements (GIC), Chemfil e Chemflex (Dentsply). The cements were manipulated according to the manufacturer's recommendation. The especimens were divided into five groups: group 1 uncoated (control group); group 2 petroleum jelly; group 3 dental varnish (Cavitine, S.S.White); group 4 - fluoride varnish (Duraflur, Denstply); group 5 dentin adhesive (Magic Bond, Vigodent). To the FR test were made 40 especimens to each CIV, with dimensions of 4mm in diameter by 6 mm in length divided randomly into the groups and kept individually in plastic containers with 5 mL of deionized water. The fluoride level was registered within 04 hours, 24 hours, 3 days, 7 days and 14 days after the confection in an Expandable Íon Analyser EA 960, and the results were calculated in &#956;gF/ cm2. To the DTS test 120 especimens were made to each GIC, with dimensions of 4mm in diameter by 6mm in length divided randomly into the groups. Mechanical tests were made within 1 day and 14 days after the confection and saving of specimens individually in plastic containers with 5 mL of deionized water, in an universal tests machine EMIC DL 500 MF, and a third test was made after 14 days of des-remineralization cycles. The data was statistically treated by ANOVA and by Student Newman-Keuls (p<0,05). In the FR test the results showed that the Chemfil released a significant bigger amount of fluoride then the Chemflex. During the tests period, the petroleum jelly and the dental varnish had a similar behavior, presenting lower fluoride release then the control group in the first 4 hours, with a greater release in the second analysis (within 24 hours). The especimens protected by petroleum jelly and dental varnish had a fluoride release similar to the control group on the periods of 3, 7 and 14 days. The fluoride varnish showed a great influence in the first 24 hours. From the third analysis on, each ionomer materials characteristics became prominent, and was noticed a bigger fluoride release on the Chemfil in comparison to the Chemflex. In relation to the coated with dentin adhesive, there was a drastic decrease of fluoride release for Chemfil and Chemflex, in all of the analysis periods. In the DTS test Chemfil didnt show statistically significant difference when the diametral tensile strength of the control group was evaluated in the various periods of time (24 hours, 14 days and de-remineralization), which also happened to Chemflex. When evaluating the influence of different surface protectors on the GIC used at this study, it was noticed that for the Chemfil the surface coating had little influence on the materials behavior, having on most of the time, the same behavior as the control group. However, to the Chemflex material, the use of a surface coating such as the fluoride varnish or the dentin adhesive allowed bigger values of diametral tensile strength. The conclusion is that when the use of GIC is wanted for a short period of time the Chemfil uncoated seems the most indicated. However, if the period of use is longer, the Chemflex with the fluoride varnish protection is the most indicated.

Neste estudo avaliou-se o efeito de diferentes protetores de superfície na liberação de flúor (LF) e na resistência à tração diametral (TD) de dois cimentos de ionômero de vidro (CIV) convencionais restauradores, Chemfil e Chemflex (Dentsply). Manipulou-se os cimentos segundo as recomendações do fabricante, os espécimes confeccionados foram divididos em cinco grupos: grupo1 sem protetor (controle); grupo2 vaselina sólida; grupo3 verniz (Cavitine, S.S.White); grupo4 verniz fluoretado (Duraflur, Denstply); grupo5 adesivo (Magic Bond, Vigodent). Confeccionou-se para o teste de LF 40 espécimes para cada CIV, com dimensões de 4 mm de diâmetro por 6 mm de comprimento, divididos aleatoriamente entre os grupos e estocados individualmente em potes plásticos contendo 5 ml de água deionizada. Registrou-se o nível de fluoreto no período de 04 horas, 24 horas, 03 dias, 07 dias e 14 dias após a confecção, em um analisador Expandable Íon Analyser EA 960, sendo os resultados calculados em &#956;gF/ cm2. Confeccionou-se para o ensaio de TD 120 espécimes para cada CIV, com dimensões de 4 mm de diâmetro por 6 mm de comprimento, divididos aleatoriamente entre os grupos. Realizou-se ensaios mecânicos, com 1 dia e 14 dias após a confecção e estocagem individual dos espécimes em potes plásticos contendo 5 ml de água deionizada, em uma máquina universal de ensaios EMIC DL 500 MF, realizou-se um terceiro teste após 14 dias de ciclos de des-remineralização. Tratou-se estatisticamente os dados obtidos por ANOVA e por Student Newman-Keuls (p<0,05). No teste de LF os resultados demonstraram que o Chemfil liberou uma quantidade significantemente maior de flúor do que o Chemflex. Durante o período do teste a vaselina e o verniz tiveram um comportamento semelhante, mostrando uma menor LF do que o grupo controle nas primeiras 4 horas, com uma maior liberação na análise seguinte (24 horas). Os espécimes protegidos com vaselina e verniz, tiveram uma liberação de flúor semelhante ao grupo controle nos períodos de 3, 7 e 14 dias. O verniz fluoretado mostrou uma forte influência nas primeiras 24 horas. A partir da terceira análise observou-se uma maior liberação de flúor para o Chemfil em comparação com o Chemflex. Em relação ao emprego de um protetor superficial resinoso, encontrou-se tanto para Chemfil quanto para o Chemflex uma redução drástica na liberação de fluoreto, em todos os tempos analisados. No ensaio de TD o Chemfil não mostrou diferença estatisticamente significante quando os resultados de TD do seu grupo controle foram avaliados nos diferentes ensaios (24 horas, 14 dias e des-re), o mesmo acontecendo com o Chemflex. Ao se avaliar a influência dos diferentes protetores de superfície nos CIVs utilizados no presente trabalho observou-se que, para o Chemfil os protetores de superfície tiveram pouca influência no comportamento do material, se comportando na maioria das vezes de forma similar ao grupo controle. Em contrapartida, para o material Chemflex a utilização de um protetor de superfície, como o verniz fluoretado e o adesivo, permitiu maiores valores de resistência à TD. Conclui-se que quando se objetiva o uso do CIV por um curto período o Chemfil sem protetor parece ser o mais indicado, porém se o uso do CIV for por um longo período o Chemflex com a proteção do verniz fluoretado é o mais indicado. / This study evaluated the effect of different protective coatings on the fluoride release (FR) and on the diametral tensile strength (DTS) of two conventional restorative glass ionomer cements (GIC), Chemfil e Chemflex (Dentsply). The cements were manipulated according to the manufacturer's recommendation. The especimens were divided into five groups: group 1 uncoated (control group); group 2 petroleum jelly; group 3 dental varnish (Cavitine, S.S.White); group 4 - fluoride varnish (Duraflur, Denstply); group 5 dentin adhesive (Magic Bond, Vigodent). To the FR test were made 40 especimens to each CIV, with dimensions of 4mm in diameter by 6 mm in length divided randomly into the groups and kept individually in plastic containers with 5 mL of deionized water. The fluoride level was registered within 04 hours, 24 hours, 3 days, 7 days and 14 days after the confection in an Expandable Íon Analyser EA 960, and the results were calculated in &#956;gF/ cm2. To the DTS test 120 especimens were made to each GIC, with dimensions of 4mm in diameter by 6mm in length divided randomly into the groups. Mechanical tests were made within 1 day and 14 days after the confection and saving of specimens individually in plastic containers with 5 mL of deionized water, in an universal tests machine EMIC DL 500 MF, and a third test was made after 14 days of des-remineralization cycles. The data was statistically treated by ANOVA and by Student Newman-Keuls (p<0,05). In the FR test the results showed that the Chemfil released a significant bigger amount of fluoride then the Chemflex. During the tests period, the petroleum jelly and the dental varnish had a similar behavior, presenting lower fluoride release then the control group in the first 4 hours, with a greater release in the second analysis (within 24 hours). The especimens protected by petroleum jelly and dental varnish had a fluoride release similar to the control group on the periods of 3, 7 and 14 days. The fluoride varnish showed a great influence in the first 24 hours. From the third analysis on, each ionomer materials characteristics became prominent, and was noticed a bigger fluoride release on the Chemfil in comparison to the Chemflex. In relation to the coated with dentin adhesive, there was a drastic decrease of fluoride release for Chemfil and Chemflex, in all of the analysis periods. In the DTS test Chemfil didnt show statistically significant difference when the diametral tensile strength of the control group was evaluated in the various periods of time (24 hours, 14 days and de-remineralization), which also happened to Chemflex. When evaluating the influence of different surface protectors on the GIC used at this study, it was noticed that for the Chemfil the surface coating had little influence on the materials behavior, having on most of the time, the same behavior as the control group. However, to the Chemflex material, the use of a surface coating such as the fluoride varnish or the dentin adhesive allowed bigger values of diametral tensile strength. The conclusion is that when the use of GIC is wanted for a short period of time the Chemfil uncoated seems the most indicated. However, if the period of use is longer, the Chemflex with the fluoride varnish protection is the most indicated.

Calcium phosphate cements (CPCs) are used as bone void fillers and as complements to hardware in fracture fixation. The aim of this thesis was to investigate the possibilities and limitations of the CPCs’ mechanical properties, and find out if these ceramic bone cements can carry application-specific loads, alone or as part of a construct. Recently developed experimental brushite and apatite cements were found to have a significantly higher strength in compression, tension and flexion compared to the commercially available CPCs chronOS™ Inject and Norian® SRS®. By using a high-resolution measurement technique the elastic moduli of the CPCs were determined and found to be at least twice as high compared to earlier measurements, and closer to cortical bone than trabecular bone. Using the same method, Poisson's ratio for pure CPCs was determined for the first time. A non-destructive porosity measurement method for wet brushite cements was developed, and subsequently used to study the porosity increase during in vitro degradation. The compressive strength of the experimental brushite cement was still higher than that of trabecular bone after 25 weeks of degradation, showing that the cement can carry high loads over a time span sufficiently long for a fracture to heal. This thesis also presents the first ever fatigue results for acidic CPCs, and confirms the importance of testing the materials under cyclic loading as the cements may fail at stress levels much lower than the material’s quasi-static compressive strength. A decrease in fatigue life was found for brushite cements containing higher amounts of monetite. Increasing porosity and testing in a physiological buffer solution (PBS), rather than air, also decreased the fatigue life. However, the experimental brushite cement had a high probability of surviving loads found in the spine when tested in PBS, which has previously never been accomplished for acidic CPCs. In conclusion, available brushite cements may be able to carry the load alone in scenarios where the cortical shell is intact, the loading is mainly compressive, and the expected maximum stress is below 10 MPa. Under such circumstances this CPC may be the preferred choice over less biocompatible and non-degradable materials.