Search

Background: The surface of resin composite veneers is susceptible to the effect of the oral environment and surface profile characterization of different veneer systems is of importance to the longevity and clinical performance of the materials. The aim of the present study was to evaluate surface profile properties, as defined by gloss and roughness parameters, of prefabricated resin composite veneers (PCV) and compare with a laboratory resin composite (LRC) system, following simulated abrasion., Material and Methods: Twenty eight composite veneers equally divided to a prefabricated composite veneer (PCV) system and a laboratory resin composite (LRC) (control group) were tested following abrasion under a toothbrush simulator. Alterations in gloss (ΔGloss) and roughness (ΔSa, ΔSz, ΔSci, ΔSdr) parameters were examined (after- before abrasion) using a glossmeter and a 3D-optical profilometer, respectively. Correlation matrices between ΔGloss and ΔRoughness parameters were sought across the two resin composite veneer groups., Results: Τhere was weak evidence that the PCV group exhibited less change in surface gloss after experimental abrasion (PCV vs LRC: mean difference ΔGloss in GU, (MD: -1.7; 95% CI: -3.3, -0.1; p =0.04). For the roughness parameters, ΔSci in nm3/nm2 (MD : 0.2; 95% CI: 0.1, 0.3; p =0.002) and ΔSdr in percentage (MD: 10.6; 95% CI: 3.7, 17.5; p =0.004), exhibited the most pronounced differences between the groups with strong evidence demonstrating greater changes for the PCV group compared to the LRC. No strong correlation pattern could be identified between changes in gloss and roughness parameters across the groups., Conclusions: After abrasion, both PCV and LCR showed an increase in surface gloss, while the PCV group demonstrated a rougher core surface profile than LRC. Key words: Prefabricated, resin composite, veneers, gloss, roughness., Competing Interests: Conflicts of interest None declared., (Copyright: © 2023 Medicina Oral S.L.)

Purpose: The aim of the present case report was to describe, through a clinical case, a step-by-step technique, for the digital selection of composite resin shades using cross polarization and white balance employing a standardized reference card., Case Description: After intraoral impression, a digital diagnostic wax up was developed. A 3D printed cast was used to fabricate a lingual polyvinyl siloxane matrix. First a cross-polarized image of the contralateral central incisor was taken in RAW format, using a gray reference card. The digital image was manipulated using this card as a reference, to obtain reliable color values. The obtained color values, from the contralateral central incisor, were used in order to digitally find the closest combination of enamel and dentin shades between various composite systems. The values of a combination of shades of composite systems, was captured using cross-polarized images, with a gray reference card, after digital image manipulation of composite specimens, which have been created for this purpose., Conclusions: Digital evaluation and selection of composite resin system and shade, using a white balance reference card assisted by cross polarized photography, could help achieving more predictable outcomes using the stratification technique with composites. Key words: Restoration shade, composite color, composite resin, direct restoration, digital protocol., Competing Interests: Conflicts of interest None declared., (Copyright: © 2021 Medicina Oral S.L.)

The modified semidirect onlay technique with articulated elastic model involves the fabrication of a stone model that is quickly mounted on an articulator and it includes an elastic part that enables the fabrication of a restoration with proper occlusal anatomy. The technique overcomes the disadvantages of the direct technique such as polymerization shrinkage stress and difficulty in achieving proper contours and, compared to the indirect technique, treatment is completed in a single appointment, without laboratory cost. The novelty of the technique is that, since the restoration is fabricated on an articulated model it eliminates time for occlusal adjustments.

The purpose of the study was to determine the influence of light-irradiation through two ceramic and one resin composite materials on the degree of remaining double carbon bonds in 3 dual-polymerized resin cements. After mixing, the cement was inserted into a 0.5 mm deep recess in a silicon mold, covered with one ceramic or resin composite rectangular block and exposed through the block with the light from a halogen polymerization unit for 40 s. Infrared spectroscopic analysis was used to record the degree of remaining double carbon bonds. Light irradiation through 2 mm-thick ceramic and resin composite materials increased the degree of remaining double carbon bonds relative to the direct photopolymerization analogues.

The critical point of the clinical procedure of direct splinting is the placement of the fiber-reinforced strip, which has to be well adapted to tooth surfaces. This article describes the use of aluminum foil to cover and protect the fiber-reinforced strip from light polymerization during the direct splinting technique. The advantage of using aluminum foil is to prevent premature curing of the fiber-reinforced strip, which would necessitate repetition of the procedure. With this technique, the strip is gradually exposed and adapted to the lingual/palatal surfaces of the teeth and light cured, allowing for ample working time.

This in vitro study compared the retentive ability of 11 materials used to cement cast crowns on one implant system. The crowns were cemented to the abutments and the tensile load necessary to remove each casting was measured 30 minutes after cementation in a dry condition at 22 degrees C and after storage for 72 hours in saline solution at 37 degrees C. The results provide a ranking order of the tested materials according to their ability to retain implant restorations. This information, along with studies that better represent the effect of aging, may assist the clinician in selecting a material that is retentive enough to withstand occlusal forces, yet weak enough to allow easy retrieval of cement-retained implant restorations.