Medium-term evaluation of the bond strength and dentin penetration of self-adhesive resin cements to root dentin.

BACKGROUND: Medium-term evaluate the bond strength and tag formation in root dentin using self-adhesive cements Maxcem Elite (MCE), Relyx U200 (RU2), SeT PP (SPP) and Megalink (MGL) compared to conventional cement Relyx ARC (ARC) for glass fibre post cementation. MATERIALS AND METHODS: One hundred bovine incisors roots were endodontically treated and divided into 5 groups (n = 20) according to the cementation system: MCE, RU2, SPP, MGL and ARC. All cementation systems were evaluated at 24 h (1) and 12 months (2) after post cementation. Specimens from the cervical, middle and apical thirds of the root were submitted to push-out bond strength test and confocal laser microscopy to verify the dentin penetration. The adhesive failure mode was classified as adhesive, cohesive and mixed. Data were analysed by one-way ANOVA and Tukey tests (α = 5%). RESULTS: ARC-1 and ARC-12 showed the highest bond strength (P < 0.05). ARC showed the greatest tag extension, regardless of the third (P < 0.05). The most frequent failure mode in the 24-h analysis was cohesive, regardless of the cement used. For the 12-month analysis, mixed failure was the most frequent. CONCLUSION: Conventional cement (ARC) showed the highest bond strength and tag extension, regardless of the evaluation period. In all cementation systems, the bond strength decreased after 12 months. © 2023 Australian Dental Association.

The action of demineralized bovine bone matrix on bone neoformation in rats submitted to experimental alcoholism / Ação da matriz óssea bovina desmineralizada na neoformação óssea em ratos submetidos ao alcoolismo experimental

The objective of this study was to evaluate whether demineralized bovine bone (Gen-ox®) alters bone neoformation in rats submitted to alcoholism. Forty male rats were separated into two groups of 20 rats and distributed as follows: Group E1, which received 25% ethanol and a surgical cavity filled only by a blood clot, and Group E2, which received 25% ethanol and a surgical cavity filled with Gen-ox®. The animals were euthanized at 10, 20, 40 and 60 days after surgery and necropsy was performed. The histomorphological and histometric analyses of the area of connective tissue and bone neoformation showed that the reorganization of the bone marrow and full repair of the surgical cavity in Group E1 occurred more quickly than in Group E2. It was also noted that in the final period the animals in Group E2 showed areas of connective tissue and thick bone trabeculae around the particles of the implant. It can be concluded that the use of Gen-ox® delayed the process of bone repair in alcoholic rats, although it can be used as filling material because it shows osteoconductive activity, as evidenced by bone tissue formation around the graft particles.

O objetivo deste trabalho foi avaliar se a matriz óssea bovina desmineralizada (Gen-ox®) altera a neoformação óssea em ratos submetidos ao alcoolismo. Foram utilizados 40 ratos machos, separados em dois grupos de 20 animais cada, assim distribuídos: Grupo E1, que recebeu etanol a 25% e cavidade cirúrgica preenchida por coágulo sanguíneo, e Grupo E2, que recebeu etanol a 25% e cavidade cirúrgica preenchida por Gen-ox®. Os animais foram eutanasiados aos 10, 20, 40 e 60 dias após a cirurgia. Os estudos histomorfológico e histométrico da quantidade de tecido conjuntivo presente e a quantidade de tecido ósseo neoformado demostraram que a reorganização da medula óssea e a reparação total da cavidade cirúrgica no Grupo E1 ocorreram em menor espaço de tempo do que no Grupo E2. Observou-se também que, no período final do experimento, os animais do Grupo E2 apresentaram áreas de tecido conjuntivo e trabéculas ósseas espessas ao redor das partículas do material implantado. Concluiu-se que a utilização do Gen-ox® retardou o processo de reparação óssea em ratos alcoolizados, muito embora o Gen-ox® possa ser utilizado como material de preenchimento, pois demonstra atividade osteocondutiva, com a formação de tecido ósseo ao redor das partículas do enxerto.

Morphometry and histochemistry of the semitendinosus muscle of tufted capuchin monkeys (Cebus apella Linnaeus, 1758).

Considering monkeys are animals closely related to the human, and semitendinosus muscle has been used in many postural research experiments, we have decided to study its histochemical characteristics. Samples were removed from the proximal, middle and distal regions of the semitendinosus muscles of five adult male tufted capuchin monkeys and observed for reaction with m-ATPase (with alkaline and acid pre-incubation), nicotinamide adenine dinucleotide tetrazolium reductase, and haematoxylin and eosin. The muscle fibres were classified as fast glycolytic (FG), fast oxidative glycolytic (FOG) and slow oxidative (SO) and quantified in terms of frequency and area. The three regions of the semitendinosus muscle showed no significant differences in frequency or area of the respective fibre types, and therefore the muscle can be considered histoenzymologically homogeneous. FG fibres presented higher frequencies and larger areas. The sum of FOG and SO fibres was 57.5%, suggesting that the semitendinosus muscle of the tufted capuchin monkey is adapted to an action involved in posture maintenance and in long arboreal dislocation. The present data agrees with the notion of differentiated quadrupedalism in some primates, which support a lower percentage of their weight on the fore limbs.