Objective Preheated resins (PR) are considered a cementing agent option for indirect adhesive restorations of composite inlays and onlays. The objective of this in vitro study was to evaluate the marginal sealing, adhesive interface, and microtensile bond strength of indirect adhesive restorations of composites in terms of dentin cemented with PR.
Materials and Methods Standardized Class II preparations were performed on 30 extracted human premolars, impressions were taken, and indirect composite restorations were manufactured. In total, 15 restorations were cemented with PR (ENA HRi, SYNCA), and 15 restorations were cemented with self-adhesive resinous cement (RC) (Relyx U200, 3M ESPE), followed by a thermocycling regime. After that, these were segmented sagittally and longitudinally to evaluate the marginal sealing and the adhesive interface with scanning electron microscopy and confocal microscopy. Microtensile bond strength was assessed with a mechanical device (TA. XT Plus C, Stable Micro System).
Statistical analysis Statistical analysis was conducted using the two-sample Student’s t-test.
Results The results showed that there is no statistically significant difference in the degree of microfiltration using PR or RC; however, microtensile bond strength is greater when the restoration is cemented with RC (278.75 N/cm3) than with PR (144.49 N/cm3), and better adjustment and sealing were observed for composite restorations with PR.
Conclusion PR comprise an alternative cementing agent for indirect composite restorations in Class II cavities in premolars.
The objective of this study was to evaluate the clinical efficacy of 5% sodium hypochlorite solution for removal of stains caused by dental fluorosis in young patients. A clinical trial involved 33 patients with diffuse opacities on the enamel surfaces of maxillary incisors due to effects of dental fluorosis. The protocol of treatment 3 steps:(1) cleaning and enamel etching with 37% phosphoric acid in order to eliminate the layer that covers the fluorotic enamel surface and allow better penetration of the bleaching agent,(2) application of 5% sodium hypochlorite to remove stains caused by organic material, and (3) filling the opened microcavities with a light-cured, composite surface sealant to prevent restaining. The whiteness of the enamel lesions before and after treatment were expressed in L*, a*, and b* color space measurements using a Minolta Chroma Meter CR300. Analysis of parameters of ¢E (L*, a*, b*) showed that changes were observed in the L* (brightness) and a* (redness), which paralleled the ¢E differences. There was no significant difference in the b* (yellow) parameter. The technique described in this study appears to have advantages over other methods for improving the appearance of fluorotic lesions. It is simple, low cost, non invasive so the enamel keeps its structure, relatively rapid, and safe; it requires no special materials, and it can be used with safety on young permanent teeth.
Application of regenerative medicine technology provides treatment for patients with several clinical problems, like loss of tissue and its function. The investigation of biological tooth replacement, dental tissue engineering and cell culture, scaffolds and growth factors are considered essential. Currently, studies reported on the making of threedimensional tissue constructs focused on the use of animal cells in the early stages of embryogenesis applied to young biomodels. The purpose of this study was the development and characterization of a three-dimensional tissue construct from human dental cells. The construct was detached, cultured and characterized in mesenchymal and epithelial cells of a human tooth germ of a 12 year old patient. The cells were characterized by specific membrane markers (STRO1, CD44), making a biocomplex using Pura Matrix as a scaffold, and it was incubated for four days and transplanted into 30 adult immunosuppressed male Wistar rats. They were evaluated at 6 days, 10 days and 2 months, obtaining histological sections stained with hematoxylin and eosin. Cell cultures were positive for specific membrane markers, showing evident deviations in morphology under phase contrast microscope. Differentiation and organization were noted at 10 days, while the constructs at 2 months showed a clear difference in morphology, organization and cell type. It was possible to obtain a three-dimensional tissue construct from human dental ectomesenchymal cells achieving a degree of tissue organization that corresponds to the presence of cellular stratification and extracellular matrix.
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