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Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Author-supplied Abstracts.)

The article discusses how digital design and manufacturing of an interim prosthesis from Valplast.

Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The use of computer‐aided design/computer‐aided manufacturing (CAD/CAM) and additive manufacturing in maxillofacial prosthetics has been widely acknowledged. Rapid prototyping can be considered for manufacturing of auricular prostheses. Therefore, so‐called prostheses replicas can be fabricated by digital means. The objective of this study was to identify a superior additive manufacturing method to fabricate auricular prosthesis replicas (APRs) within a digital workflow. Materials and Methods: Auricles of 23 healthy subjects (mean age of 37.8 years) were measured in vivo with respect to an anthropometrical protocol. Landmarks were volumized with fiducial balls for 3D scanning using a handheld structured light scanner. The 3D CAD dataset was postprocessed, and the same anthropometrical measurements were made in the CAD software with the digital lineal. Each CAD dataset was materialized using fused deposition modeling (FDM), selective laser sintering (SLS), and stereolithography (SL), constituting 53 APR samples. All distances between the landmarks were measured on the APRs. After the determination of the measurement error within the five data groups (in vivo, CAD, FDM, SLS, and SL), the mean values were compared using matched pairs method. To this, the in vivo and CAD dataset were set as references. Finally, the surface structure of the APRs was qualitatively evaluated with stereomicroscopy and profilometry to ascertain the level of skin detail reproduction. Results: The anthropometrical approach showed drawbacks in measuring the protrusion of the ear's helix. The measurement error within all groups of measurements was calculated between 0.20 and 0.28 mm, implying a high reproducibility. The lowest mean differences of 53 produced APRs were found in FDM (0.43%) followed by SLS (0.54%) and SL (0.59%)––compared to in vivo, and again in FDM (0.20%) followed by SL (0.36%) and SLS (0.39%)––compared to CAD. None of these values exceed the threshold of clinical relevance (1.5%); however, the qualitative evaluation revealed slight shortcomings in skin reproduction for all methods: reproduction of skin details exceeding 0.192 mm in depth was feasible. Conclusion: FDM showed the superior dimensional accuracy and best skin surface reproduction. Moreover, digital acquisition and CAD postprocessing seem to play a more important role in the outcome than the additive manufacturing method used. [ABSTRACT FROM AUTHOR]

The article reports on the use of gold dental restorations over the years. It is said that the dental industry has seen a dramatic decline in the consumption of high gold content alloys over the last decade. Not only the fluctuating gold price seems to be responsible for this, but also an increase in digital manufacturing capabilities, along with the increased demand for metal-free tooth-colored materials.

Copyright of Quintessenz der Zahntechnik is the property of Quintessenz Verlags GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose The purpose of this in vitro study was to assess the effect of varying the margin designs and the occlusal thicknesses on the fracture resistance and mode of failures of endodontically treated teeth restored with polymer infiltrated ceramic endocrown restorations. Methods Root canal treated mandibular molars were divided into four groups ( n = 8) and were prepared to receive Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) fabricated polymer infiltrated ceramic endocrowns (ENAMIC blocks). Group B2 represents teeth prepared with a butt joint design receiving endocrowns with 2 mm occlusal thickness and the same for group B3.5 but with 3.5 mm occlusal thickness. Group S2 represents teeth prepared with 1 mm shoulder finish line receiving endocrowns with 2 mm occlusal thickness and the same for group S3.5 but with 3.5 mm occlusal thickness. After cementation and thermal aging, fracture resistance test was performed and failure modes were observed. Results Group S3.5 showed the highest mean fracture load value (1.27 ± 0.31 kN). Endocrowns with shoulder finish line had significantly higher mean fracture resistance values than endocrowns with butt margin ( p < 0.05). However, the results were not statistically significant regarding the restoration thickness. Evaluation of the fracture modes revealed no statistically significant difference between the modes of failure of tested groups. Conclusions For the restoration of endodontically treated teeth, adding a short axial wall and shoulder finish line can increase the fracture resistance. However, further investigations, especially the fatigue behavior, are needed to ensure this effect applies with small increases of restoration thickness. [ABSTRACT FROM AUTHOR]

This study analyzed the shear bond strength (SBS) of resin composite on zirconia surface to which a specific conditioner was applied before sintering. After sintering of either conditioner-coated or uncoated specimens, both groups were divided into three subgroups by their respective surface modifications (n = 10 per group): no further treatment; etched with hydrofluoric acid; and sandblasted with 50 μm Al2O3 particles. Surfaces were characterized by measuring different surface roughness parameters (e.g., Ra and Rmax) and water contact angles. Half of the specimens underwent thermocycling (10,000 cycles, 5–55 oC) after self-adhesive resin cement build-up. The SBSs were measured using a universal testing machine, and the failure modes were analyzed by microscopy. Data were analyzed by nonparametric and parametric tests followed by post-hoc comparisons (α = 0.05). Conditioner-coated specimens increased both surface roughness and hydrophilicity (p < 0.01). In the non-thermocycled condition, sandblasted surfaces showed higher SBSs than other modifications, irrespective of conditioner application (p < 0.05). Adhesive fractures were commonly observed in the specimens. Thermocycling favored debonding and decreased SBSs. However, conditioner-coated specimens upon sandblasting showed the highest SBS (p < 0.05) and mixed fractures were partially observed. The combination of conditioner application before sintering and sandblasting after sintering showed the highest shear bond strength and indicated improvements concerning the failure mode. [ABSTRACT FROM AUTHOR]

An editorial is presented which argues on Technology development at a breakneck pace, which includes deals with digital supported model and auxiliary part production, the additive ones manufacturing processes are current time at another high point and will be in the next years will certainly be exciting offer in terms of further development of materials, devices and software solutions. The printing technologies approved corresponding 3-D printers that do it enable dental laboratory.

The "activation" of titanium implants by UV‐irradiation is reported to enhance osseointegration in vitro as well as in vivo. Anatase‐enriched titanium oxide surfaces enable, via photocatalysis, a chairside "activation" of implants by short‐term UVA (382 nm) irradiation. The potentially improved clinical performance of these modified surfaces depends not only on the achieved photocatalytic activity, but also on the effects caused by the micro‐ and nanostructure of the respective surface modification. In this study, three differently manufactured anatase‐coated titanium surfaces are characterized regarding surface characteristics, photocatalytic efficiency, and their ability to promote proliferation and differentiation of osteoblasts in comparison to conventional sandblasted (S) and blasted/etched (S/A) titanium implant surfaces. Anatase surfaces are manufactured by suspension plasma spraying (SPS), precursor‐based liquid film coating (PLC), and physical vapor deposition (PVD). The tested surfaces exhibit significantly different surface morphologies and anatase/rutile ratios. UVA‐irradiation of samples prior to cell seeding leads to significantly improved cell proliferation and surface coverage. UVA‐treatment also leads to a generally enhanced osteoblastic differentiation of cells on all anatase‐coated surfaces. The anatase‐enriched titanium surface modifications promote different aspects of osteoblast reactions, suggesting that the "activation" of anatase‐coated titanium implants by UVA treatment is a promising chairside procedure for dental implant optimization. Anatase‐enriched, photocatalytically active titanium surface modifications stimulated different aspects of the biological response of osteoblast‐like cells. Different cell reactions on the respective surfaces can be explained by differing photocatalytic activity, surface hydrophilicity and surface topography. The results suggest that the proposed chairside "activation" of anatase‐coated titanium implants by UVA irradiation (382 nm) is a promising approach for further implant optimization. [ABSTRACT FROM AUTHOR]

Titanium dental implants with sandblasted and/or acid-etched surfaces have shown clinical superiority in comparison to their smooth, machined counterparts, and are now state of the art. Sandblasting of finished, sintered zirconia implants, however, will damage the surface structure and affect the mechanical properties. To improve osseointegration of zirconia dental implants without impairing the original mechanical strength by crack initiation and partial phase transformation from tetragonal to monoclinic, roughening of the zirconia surface by sandblasting before the final sintering step was employed. Impact of the treatments on cellular reactions of SAOS-2 human osteoblast-like cells was investigated. Sandblasting of Yttrium-stabilized zirconia (Y-TZP) with 120 μm and 250 μm Al2O3 enhanced average roughness (Sa) from 0.28 μm to 4.1 μm and 5.72 μm, respectively. Cell adhesion of SAOS-2 osteoblasts was enhanced up to 175% on sandblasted surfaces, compared to the machined zirconia reference (100%). Metabolic activity and proliferation in the logarithmic growth phase (24-48 h) were not significantly affected. Sample surface coverage by the cells after prolonged incubation (72 h) was markedly decreased on the roughened samples, indicating a shift towards increased differentiation on these surfaces. The approach investigated here to roughen zirconia implants by sandblasting before sintering shows potential to improve the clinical performance of ceramic dental implants.

Adequate bonding between dental veneering porcelains and non-precious metal alloys is a main factor for the long-term functionality of porcelain fused to metal restorations. Although a huge number of veneering porcelains are on the market, only few studies have reported about the role of bonding agents for the bond strength at their respective interface to cobalt-chromium (Co-Cr). The aim of this study was to compare the influence of a metal-ceramic bonding agent for Co-Cr alloys on the bond strength of metal-ceramic systems. The bond strength test was done according to ISO 9693 with additional detection of the first acoustic crack initiated signal while testing. The bonding agent had only minor effects on the bond strength of the different Co-Cr/ceramic systems. Only three of the nine studied systems showed statistically significant differences (p<0.05) upon applying the bonding agent. Scanning electron microscopy (SEM) showed cracks predominantly caused by adhesive failure. Based on this study, Co-Cr alloys veneered with porcelains with and without a bonding agent exceeded the minimum bond strength of 25 MPa required according to ISO 9693. However, if bond strength values based on acoustic signals were calculated, values below the threshold of 25 MPa could be observed. Such findings are important for failures caused by the occurrence of early cracks.