Three-dimensional Quantitative Porosity Characterization of Syringe- versus Hand-mixed Set Epoxy Resin Root Canal Sealer

The aim of the present study was to compare the porosity characteristics of AH Plus Jet(tm) syringe-mix and the conventional hand-mixed AH Plus root canal sealers by three-dimensional quantitative high-resolution micro-computed tomography (micro-CT). Seven test specimens were prepared from each tested sealer by a single operator following the manufacturer's instructions and poured into pre-lubricated plastic split-ring moulds. Set sealer test specimens were scanned using a micro-CT device and the shadow images were reconstructed into cross-sectional slices. The evaluated parameters were (i) total pore count, (ii) total pore volume and mean pore volume, (iii) total porosity (% of pore volume in relation to total sealer volume) and (iv) mean pore distance to the sealer lateral external surface. In both groups, most pores were localized within the external sealer perimeter (0.05 mm from the external surface). Hand-mixed AH Plus specimens showed statistically significant higher mean total pore count, total pore volume and total porosity (p=0.001) than the syringe-mixed specimens. However, mean pore sizes in AH Plus syringe-mixed specimens were significantly higher (p=0.046) than the AH Plus hand-mixed counterparts. Hand-mixed AH Plus was associated with higher total mean pore count, volume and total porosity compared to syringe mixed AH Plus.

Resumo O objetivo do presente estudo foi comparar a porosidade do AH Plus Jet(tm) dotado de misturador automático com o AH Plus convencional manipulado a mão a partir de um método quantitativo de microtomografia computadorizada (micro-CT). Para cada cimento, sete espécimes foram preparados por um único operador, seguindo as instruções do fabricante, e inseridas em anéis de plástico. Após o tempo de presa, os cimentos foram escaneados utilizando o micro-CT e as imagens foram reconstruídas. Os parâmetros avaliados foram (i) contagem total de poros, (ii) volume total de poros e média dos volumes dos poros, (iii) porosidade total (% de volume de poros em relação ao volume total do cimento) e (iv) distância média dos poros em relação ao perímetro externo (0,05 mm da superfície externa). O AH Plus manipulado a mão apresentou maior número de poros, maior volume total de poros e porosidade total (p=0,001) comparado com o AH Plus com misturador. No entanto, a média de tamanho dos poros foi estatisticamente superior no AH Plus com misturador quando comparado com o AH Plus manipulado a mão (p=0,046). O AH Plus manipulado a mão foi associado com uma maior média de poros, volume e porosidade quando comparado com o AH Plus com misturador.

Bacteriology of deep carious lesions underneath amalgam restorations with different pulp-capping materials - an in vivo analysis

Microorganisms remaining in dentin following cavity preparation may induce pulp damage, requiring the use of pulp-capping agents with antimicrobial activity underneath permanent restorations. OBJECTIVE: The aims of this study were to analyze the bacteriological status of carious dentin and to assess the efficacy of different base underneath silver amalgam restorations. MATERIAL AND METHODS: This study was conducted on 50 patients aged 13 to 30 years. Sterile swabs were used to take samples after cavity preparation, which was assessed by microbiological culture to identify the microorganisms present. Following this, cavities were restored with silver amalgam, using one of the materials being investigated, as the base: calcium hydroxide (Group II), polyantibiotic paste (Group III), a novel light-cured fluoride-releasing hydroxyapatite-based liner (Group IV) and mineral trioxide aggregate - MTA (Group V). In Group I, the cavities were restored with silver amalgam, without any base. After 3 months, the amalgam was removed and samples taken again and analyzed for the microbial flora. RESULTS: Lactobacilli were the most commonly isolated microorganisms in the samples of carious dentin. Groups IV and V showed negative culture in the 3-month samples. There was no statistically significant difference between Groups I, II and III. There was no significant difference between Groups IV and V (p>0.05). Both Groups IV and V showed significantly better results when compared to Groups I, II and III (p<0.05). CONCLUSIONS: The hydroxyapatite-based liner and MTA performed significantly better in terms of antibacterial activity than the other materials.