Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements.

The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.

O objetivo do presente estudo foi avaliar o grau de conversão, citotoxicidade, solubilidade e pH de cimentos à base de cálcio fotopolimerizáveis submetidos a pré-aquecimento. O grau de conversão foi analisado por espectroscopia no infravermelho com transformada de Fourier, a citotoxicidade pelo teste de MTT e a solubilidade através da perda de massa. Os dados foram submetidos a testes estatísticos (ANOVA/Tukey, p<0,05). Os materiais fotopolimerizáveis apresentaram baixo grau de conversão, independente do pré-aquecimento. Todos os materiais causaram redução da viabilidade celular nas análises de 24 horas e 7 dias, sendo que o Dycal (controle) apresentouse mais citotóxico e o calor apresentou efeito positivo sobre o Biocal na análise de 7 dias. O Dycal é o material mais solúvel e o calor não causou efeito na solubilidade e pH dos materiais polimerizáveis. Assim, conclui-se que os cimentos à base de cálcio fotopolimerizáveis apresentam baixo grau de conversão e são solúveis, que resulta em citotoxicidade suave e moderada.

Effect of preheating on cytotoxicity and physicochemical properties of light-cured calcium-based cements / Efeito do pré-aquecimento na citotoxicidade e propriedades físico-químicas de cimentos à base de cálcio fotopolimerizáveis

ABSTRACT The aim of this study was to evaluate the degree of conversion, cytotoxicity, solubility and pH of photopolymerizable calciumbased cements submitted to preheating. The degree of conversion was analyzed by Fourier transform infrared, cytotoxicity by the MTT test and solubility through loss of mass. The data were subjected to statistical tests (ANOVA / Tukey's, p<0.05). The photopolymerizable materials showed a low degree of conversion, regardless of preheating. All materials caused a reduction in cell viability at 24 hours and 7 days, with the Dycal (control) being more cytotoxic. Heat had a positive effect on Biocal at 7 days. Dycal is the most soluble material. Heat had no effect on the solubility or pH of the polymerizable materials. It is concluded that photopolymerizable calcium-based cements have a low degree of conversion and are soluble, which results in mild to moderate cytotoxicity.

RESUMO O objetivo do presente estudo foi avaliar o grau de conversão, citotoxicidade, solubilidade e pH de cimentos à base de cálcio fotopolimerizáveis submetidos a pré-aquecimento. O grau de conversão foi analisado por espectroscopia no infravermelho com transformada de Fourier, a citotoxicidade pelo teste de MTT e a solubilidade através da perda de massa. Os dados foram submetidos a testes estatísticos (ANOVA/Tukey, p<0,05). Os materiais fotopolimerizáveis apresentaram baixo grau de conversão, independente do pré-aquecimento. Todos os materiais causaram redução da viabilidade celular nas análises de 24 horas e 7 dias, sendo que o Dycal (controle) apresentouse mais citotóxico e o calor apresentou efeito positivo sobre o Biocal na análise de 7 dias. O Dycal é o material mais solúvel e o calor não causou efeito na solubilidade e pH dos materiais polimerizáveis. Assim, conclui-se que os cimentos à base de cálcio fotopolimerizáveis apresentam baixo grau de conversão e são solúveis, que resulta em citotoxicidade suave e moderada.

Precision and accuracy of four current 3D Printers to achieve models for Fixed Dental Prosthesis.

The aim of this study was to compare the accuracy and precision of 3D printers used to obtain models of fixed dental prostheses. A fixed dental prosthesis preparation was scanned and reproduced by four 3D printers: RapidShape P40, Asiga MAX, Varseo, and Photon. The impressions were scanned again, and the dataset was compared to the original dataset. Mean discrepancies (µm) were 52.97±20.48 (RapidShape P40), 68.27±43.53 (Asiga MAX), 62.22±56.21 (Varseo), and 80.03±28.67 (Photon). There was no difference (p=0.314) in accuracy; however, the precision differed (p=0.015) among the 3D printers. The printers had distinct precision but did not differ in accuracy.

O objetivo desse trabalho foi comparar a acurácia e a precisão de impressoras 3D utilizadas para a obtenção de modelos para prótese fixa. Um preparo para prótese fixa foi escaneado e reproduzido por 4 impressoras 3D: RapidShape 3D, Asiga MAX, Varseo e Photon. As impressões foram novamente escaneadas, e o dataset escaneado foi comparado ao original. Os escaneamentos foram sobrepostos digitalmente e determinada a discrepância entre os modelos original e impresso. A discrepância média (µm) entre os modelos foi de foi 52,97±20,48 (RapidShape 3D), 68,27±43,53 (Asiga MAX), 62,22±56,21 (Varseo) e 80,03±28,67 (Photon). Não houve diferença (p=0,314) entre os valores médios, os quais representam a acurácia; entretanto, o desvio padrão dessas foi diferente (0,015), indicando diferença na precisão das impressoras 3D.

Precision and accuracy of four current 3D Printers to achieve models for Fixed Dental Prosthesis / Precisão de quatro impressoras 3D para obtenção de modelos para prótese fixa

ABSTRACT The aim of this study was to compare the accuracy and precision of 3D printers used to obtain models of fixed dental prostheses. A fixed dental prosthesis preparation was scanned and reproduced by four 3D printers: RapidShape P40, Asiga MAX, Varseo, and Photon. The impressions were scanned again, and the dataset was compared to the original dataset. Mean discrepancies (μm) were 52.97±20.48 (RapidShape P40), 68.27±43.53 (Asiga MAX), 62.22±56.21 (Varseo), and 80.03±28.67 (Photon). There was no difference (p=0.314) in accuracy; however, the precision differed (p=0.015) among the 3D printers. The printers had distinct precision but did not differ in accuracy.

RESUMO O objetivo desse trabalho foi comparar a acurácia e a precisão de impressoras 3D utilizadas para a obtenção de modelos para prótese fixa. Um preparo para prótese fixa foi escaneado e reproduzido por 4 impressoras 3D: RapidShape 3D, Asiga MAX, Varseo e Photon. As impressões foram novamente escaneadas, e o dataset escaneado foi comparado ao original. Os esca neamentos foram sobrepostos digitalmente e determinada a discrepância entre os modelos original e impresso. A discre pância média (μm) entre os modelos foi de foi 52,97±20,48 (RapidShape 3D), 68,27±43,53 (Asiga MAX), 62,22±56,21 (Varseo) e 80,03±28,67 (Photon). Não houve diferença (p=0,314) entre os valores médios, os quais representam a acurácia; entretanto, o desvio padrão dessas foi diferente (0,015), indicando diferença na precisão das impressoras 3D.

Glycerol salicylate-based containing α-tricalcium phosphate as a bioactive root canal sealer.

The use of bioactive materials instead of inert materials to fill the root canal space could be an effective approach to achieve a hermetic seal and stimulate the healing of periapical tissues. The purpose of this study was to develop and characterize an endodontic sealer based on a glycerol salicylate resin and α-tricalcium phosphate (αTCP) at physical and chemical properties. Different sealers were formulated using 70% of a glycerol salicylate resin and 30% of a mixture of calcium hydroxide and αTCP (0, 5, 10, or 15%, in weight). Sealers formulated were characterized based on setting time, in vitro degradation over time, pH, cytotoxicity, and mineral deposition. Sealers presented setting time ranging from 240 to 405 min, and basic pH over 8.21 after 28 days. Higher αTCP concentration leads to sealers with low solubility. Cell viability after 48 h in direct contact with sealers was similar to a commercial sealer used as reference. The 10% and 15% αTCP sealers exhibited a calcium-phosphate layer on the surface after immersion in water and SBF for 7 days. Glycerol salicylate sealers with 10% and 15% α-tricalcium phosphate showed reliable physical-chemical properties and apatite-forming ability.

Oral hygiene caregivers' educational programme improves oral health conditions in institutionalised independent and functional elderly.

OBJECTIVE: The goal of this study was to determine the impact of an oral hygiene education programme for caregivers on the oral health of institutionalised elderly and to examine the effect of disability and low muscle strength on programme outcomes. MATERIALS AND METHODS: The subjects of this study were geriatric patients (n = 80) from a nursing home. Katz Index for activities of daily living, handgrip strength and mucosal-plaque score (MPS) was evaluated at baseline and 1 year after intervention. The intervention consisted of an educational programme and specific guidelines for caregivers (to perform oral hygiene for dependent elderly and to supervise the independent elderly during oral hygiene practices). Differences on MPS were evaluated using a paired-sample t-test. A stratified analysis was carried out to identify differences in response to the programme according to the Katz Index and handgrip strength of elderly. RESULTS: The MPS was significantly reduced (p = 0.001) at follow-up; however, a separate analysis showed that only the independent elderly (p = 0.002) and those with normal muscle strength (p = 0.006) showed a reduction in MPS during the follow-up examination. CONCLUSION: The oral hygiene education programme for caregivers resulted in a positive impact on oral hygiene of the independent and functional elderly.