Evaluation of Laser Fluorescence in the Monitoring of the Initial Stage of the De-/Remineralization Process: An in vitro and in situ Study

This study aimed to evaluate laser fluorescence (LF) for monitoring the initial stage of subsurface de- and remineralization (<150 mu m depth). Ninety-six sound blocks of bovine enamel, selected according to surface hardness (SH) and LF were used in two experimental studies, in vitro and in situ. In vitro, blocks were exposed to a demineralizing solution, then remineralized by pH cycling for 6 days. In situ, 10 volunteers wore acrylic palatal appliances, each containing 4 dental enamel blocks that were demineralized for 14 days by exposure to 20% sucrose solution. Following this treatment, blocks were submitted to remineralization for 1 week with fluoride dentifrice (1,100 mu g F/g). In both experiments, SH and LH were measured after demineralization and after remineralization. Further, enamel blocks were selected after the demineralization/remineralization steps for measurement of cross-sectional hardness and integrated loss of subsurface hardness (Delta KHN). SH and Delta KHN showed significant differences among the phases in each study. LF values for sound, demineralized and remineralized enamel were: 5.2 +/- 1.1, 8.1 +/- 1.2 and 5.6 +/- 0.8, respectively, in the in vitro study, and 5.3 +/- 0.3, 16.5 +/- 4.7 and 6.5 +/- 2.5, respectively, in the in situ study, values for demineralized enamel being significantly higher than for sound and remineralized enamel in both studies. However, LF was correlated with Delta KHN only in situ. LF was capable of monitoring de- and remineralization in early lesions in situ, when bacteria are presumably present in the caries lesion body, but is not correlated with mineral changes in bacteria-free systems. Copyright (C) 2009 S. Karger AG, Basel

In situ and in vitro comparison of laser fluorescence with visual inspection in detecting occlusal caries lesions

The aim of this study was to compare the in situ and in vitro performances of a laser fluorescence (LF) device (DIAGNOdent 2095) with visual inspection for the detection of occlusal caries in permanent teeth. Sixty-four sites were selected, and visual inspection and LF assessments were carried out, in vitro, three times by two independent examiners, with a 1-week interval between evaluations. Afterwards, the occlusal surfaces were mounted on the palatal portion of removable acrylic orthodontic appliances and placed in six volunteers. Assessments were repeated and validated by histological analysis of the tooth sections under a stereomicroscope. For both examiners, the highest intra-examiner values were observed for the visual inspection when in vitro and in situ evaluations were compared. The inter-examiner reproducibility varied from 0.61 to 0.64, except for the in vitro assessment using LF, which presented a lower value (0.43). The methods showed high specificity at the D(1) threshold (considering enamel and dentin caries as disease). In vitro evaluations showed the highest values of sensitivity for both methods when compared to the in situ evaluations at D(1) and D(2) (considering only dentinal caries as the disease) thresholds. For both methods, the results of sensitivity (at D(1) and D(2)) and accuracy (at D(1)) showed significant differences between in vitro and in situ conditions. However, the sensitivity (at D(1) and D(2)), specificity and accuracy (both at D(1)) of the methods were not significantly different when the same condition was considered. It can be concluded that visual inspection and LF showed better performance in vitro than in situ.

Insight into Copper-Based Catalysts: Microwave-Assisted Morphosynthesis, In Situ Reduction Studies, and Dehydrogenation of Ethanol

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Laser-assisted hatching of cryopreserved-thawed embryos by thinning one quarter of the zona

Laser-assisted hatching is little documented in the literature regarding its efficacy in cryopreserved-thawed (CT) embryo transfer cycles. The aim of the present study was to evaluate in a randomized manner the efficacy of thinning one quarter of the zona pellucida of CT embryos to a depth of 50-80% of the original thickness, via laser treatment (the qLZT-AH procedure), in improving implantation and pregnancy rates. Two populations were studied: population I, patients who had all their supernumerary embryos cryopreserved, regardless of their morphology, and population II, patients at risk of ovarian hyperstimulation syndrome who had all their embryos cryopreserved. Artificial and natural protocols were used for the embryo transfers. A total of 350 laser-thinned CT embryos were compared with 352 intact zona embryos. No difference in implantation or pregnancy rate was found after using qLZT-AH in either population. These findings suggest that qLZT-AH should not be routinely performed in cryopreserved embryo programmes.

Efeito do sistema de acabamento e polimento na rugosidade superficial e formação in situ de biofilme dentário inicial em cerâmica feldspática micro-particulada

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In situ assessment of the saliva effect on enamel morphology after microabrasion technique

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)