Evaluation of Two Approaches for Breast Surface Measurement Applied to a Radar-Based Imaging System

Locating the surface of an object, in this case the breast, is an important first step in many imaging situations; this surface information may be a necessary part of the reconstruction, it may be needed for the cancellation of the surface reflection, or (as herein) it may be needed as a preparatory step before imaging. This paper presents two complementary approaches developed for the purpose of surface localisation. The proposed approaches are evaluated using data from both phantom measurements and volunteer scans

Effectiveness of different adhesive primers on the bond strength between an indirect composite resin and a base metal alloy

Statement of problem: There is a need for achieving reliable chemical bond strength between veneering composites resins and casting alloys through the use of simplified procedures. Purpose: The purpose of this study was to examine the shear bond strength of an indirect composite resin to a Ni-Cr alloy, using 4 primers and 2 airborne-particle-abrasion procedures. Material and methods: Fifty-six Ni-Cr (Heraenium NA) discs, 10 mm in diameter and 1.5 mm in height, were fabricated. Twenty-four discs were airborne-particle abraded with 50-μm Al2O3 particles, while another 24 were airborne-particle abraded with 250-μm Al2O3 particles. The following primers were applied on 6 discs of each airborne-particle-abrasion treatment group: Solidex Metal Photo Primer (MPP50, MPP250), Metal Primer II (MPII50, MPII250), SR Link (SRL50, SRL250), and Tender Bond (TB50, TB250). The Rocatec system was used on another 6 discs, airborne-particle abraded according to the manufacturer's recommendations, which served as the control group (R). Two more discs were airborne-particle abraded with 50-μm and 250-μm Al2O3 particles, respectively, to determine the Al content on their surfaces, without any bonding procedure. The indirect composite resin used was Sinfony. Specimens were thermally cycled (5°C and 55°C, 30-second dwell time, 5000 cycles) and tested in shear mode in a universal testing machine. The failure mode was determined with an optical microscope, and selected specimens were subjected to energy dispersive spectroscopy (EDS). Mean bond strength values were analyzed using 2-way ANOVA followed by Tukey's multiple comparison tests (α=.05) and compared to the control group using 1-way ANOVA followed by Tukey's multiple comparison tests (α=.05). Results: The groups abraded with 50-μm particles exhibited significantly higher bond strength compared to the groups abraded with 250-μm particles. Group MPII50 exhibited the highest mean value (17.4 ±2 MPa). Groups MPP50, MPP250, and TB50, TB250 showed adhesive failures and significantly lower bond strength compared to group R. Groups MPII50, MPII250, and SRL50, SRL250 showed combination failures and no significant difference compared with group R. EDS revealed interfacial rather than adhesive failures. Conclusions: Airborne-particle abrasion with 50-μm Al2O3 particles may result in improved bond strength, independent of the primer used. The bond strength of Metal Primer II and SR Link specimens was comparable to that of specimens treated with Rocatec. (J Prosthet Dent 2008;99:377-387). © 2008 The Editorial Council of the Journal of Prosthetic Dentistry

A Thorough Analysis of the Endocrown Restoration: A Literature Review

Aim: The aim of this literature review is to determine whether endocrowns are a reliable alternative for endodontically treated teeth with extensive loss of tooth structure, the indications and contraindications of this restorative choice, the principles that should be followed for tooth preparation and which material is most appropriate for endocrown fabrication. Background: Rehabilitation of endodontically treated teeth with severe coronal destruction has always been a challenge for the dental clinician. Until recently, the fabrication of a metal-ceramic or all-ceramic full-coverage crown along with a metal or glass fiber post has been the “gold standard” proving its efficacy via numerous clinical studies. With the development of CAD/CAM technology and the evolution of dental materials, new minimally invasive techniques have been introduced with less need for adjustments and less incorporation of structural defects. One of them, the “monoblock technique,” proposed by Pissis in 1995, was the forerunner of endocrown restoration, a term used by Bindl and Mörmann to describe an all-ceramic crown anchored to the internal portion of the pulp chamber and on the cavity margins, thus obtaining macromechanical retention provided by the axial opposing pulpal walls and microretention attained with the use of adhesive cementation. Review results: Endocrowns require a decay-oriented preparation taking advantage of both the adhesion and the retention from the pulpchamber walls, they are strongly indicated in endodontically treated molars in cases where minimal interocclusal space and curved or narrow root canals are present and they should be manufactured from materials that can be bonded to the tooth structure. Conclusion: Endocrowns are a reliable alternative to traditional restorative choices, given that the clinicians respect the requirements and indications describing this technique. Clinical significance: Traditional restorative techniques demanding tooth substance removal and minimizing the opportunity for reinterventions should be reconsidered. © Jaypee Brothers Medical Publishers. 2021 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

The use of dental implants in combination with removable partial dentures. A case report

Implant treatment protocols for fully edentulous patients include implant-supported fixed restorations with a minimum of five to six implants or overdentures on two to four implants. However, implant placement in the posterior areas is sometimes not permitted by anatomic and/or financial restraints, or patients' unwillingness to have extensive surgical procedures. The purpose of this case report is to present a treatment option where bilateral distal extension removable partial dentures (RPDs) are used in combination with anterior fixed implant prostheses with semi-precision attachments. The initial treatment plan of a 65-year-old female with failing dentition involved the fabrication of overdentures supported by four implants placed in the interforaminal area in both arches. Because of inadequate space for the retentive elements of the overdenture and the patient's objection to surgical procedures for the placement of additional implants to support a fixed restoration, the treatment plan was modified. Fixed ceramometal cement-retained implant restorations with semi-precision attachments adjacent to the distal abutments were fabricated in the maxilla and the mandible. Bilateral distal extension RPDs were placed in both arches. The patient's benefits were increased comfort, good esthetics in the anterior area, improved phonetics, and masticatory function. Retentive element maintenance requirements were similar to conventional RPDs. More extended controlled clinical studies are needed to establish the long-term success of this treatment option. CLINICAL SIGNIFICANCE Removable partial dentures may offer an attractive treatment option for an edentulous patient, as they may combine an FPD in the anterior segment with a removable appliance in the posterior areas. A satisfying restoration can be achieved with fewer implants. (J Esthet Restor Dent 20: 355-365, 2008) © 2008 Wiley Periodicals, Inc

Immediate Dentin Sealing: A Literature Review

Theodora-Kalliopi Samartzi,1 Dimokritos Papalexopoulos,2 Aspasia Sarafianou,2 Stefanos Kourtis2 1Private Dentistry Practice, Athens, Greece; 2Department of Prosthodontics, National and Kapodistrian University of Athens, Athens, GreeceCorrespondence: Dimokritos PapalexopoulosDepartment of Prosthodontics, National and Kapodistrian University of Athens, Athens, GreeceEmail [email protected]: The immediate application of a dentin-bonding agent after tooth preparation and before impression-taking (immediate dentin sealing [IDS]) has been suggested to provide several advantages concerning bacterial microleakage, hypersensitivity, and bonding quality. We reviewed the literature and clarified certain aspects related to each step of IDS application.Materials and Methods: The search strategy comprised an electronic research in MEDLINE, Cochrane, Ovid and Scopus for studies published from January 1990 to December 2020 regarding the IDS technique and including both in vitro and clinical studies.Results: After exclusion of irrelevant or duplicate articles, 88 articles focusing on aspects of the IDS technique were assessed. IDS seems to be advantageous with regard to bond strength, gap formation, bacterial microleakage, and dentin hypersensitivity. However, issues arising from interaction with impression materials, the provisional phase, and conditioning methods before cementation require further investigation.Conclusion: There are no documented reasons preventing clinicians applying IDS in their everyday practice. On the contrary, the presented technique seems to be beneficial in certain aspects regarding indirect restorations.Keywords: IDS, indirect restorations, restorative dentistry, revie

Shear bond strength of three veneering resins to a Ni-Cr alloy using two bonding procedures

SUMMARY Composite veneering materials are used as alternatives to porcelain in fixed prosthodontics. Mechanical retention of the resin on the metal framework has been associated with the formation of gaps at the resin/alloy interface, and failure of the restoration. Several chemical bonding systems have been introduced to promote resin adhesion. The purpose of the present study was to evaluate the shear bond strength of three photocured composites (Artglass, Solidex & Signum+) to a Ni-Cr alloy.72 wax disks covered with 150-lm diameter beads were cast and divided in two equal groups. In the first group, Metal Photo Primer was applied on the casting surface, while the Siloc system was used in the second. Each group was divided in three subgroups of 12 samples, in which the three composites were photocured. Half of the specimens of each subgroup were subjected to 1000 and 5000 thermal cycles (5 and 55 °C) respectively. All specimens were tested in shear in a universal testing machine. The Siloc-Solidex group showed the highest bond strength (17±3 ° 3±7 MPa). No statistically significant difference was found between specimens treated with Metal Photo Primer or Siloc. Thermocycling did not significantly affect the bond strength values. Solidex showed an adhesive failure mode for both alloy surface treatments, while Artglass and Signum+ exhibited combination failures. Conclusively, the appropriate alloy surface treatment - resin combination can significantly improve the resin-alloy shear bond strength. Specifically, Solidex resin exhibited significantly higher bond values compared with Artglass and Signum±, for both surface treatments and thermocycling procedures. © 2006 Blackwell Publishing Ltd

Surface characteristics and color stability of gingiva-colored resin composites

The purpose of this study was to investigate the surface characteristics and color stability of gingiva-colored composite restorative materials (Anaxgum-ANG, Ceramage-CMG and Gradia Gum-GRG). The microstructure, composition, degree of conversion (DC %) and 3D roughness (Sa, Sz, Sdr, Sc) were examined by LV-SEM/EDS, ATR-FTIR and optical profilometry, respectively. For the color stability (CIE L*, a*, b* system) and hardness (HV), measurements were performed at baseline and after 30 days storage in distilled water, coffee and red wine. The ANG and GRG contain prepolymerized particles in aromatic and aliphatic resin matrices, respectively, whereas CMG contains inorganic zirconia silicate/silica particles, in an aromatic resin matrix, with a smaller particle size and a higher surface area fraction. Urethane monomers were mainly identified in CMG and GRG. The DC% showed statistically insignificant differences between the materials. The same applied for the roughness parameters, except for the greatest Sdr in CMG. ANG showed a color difference (ΔE) of > 3.3 after immersion in all media, CMG in coffee and wine and GRG only in coffee. Sc was the only roughness parameter demonstrating correlations with the ΔL*, Δb* and ΔE*. The HV values showed insignificant differences between the storage conditions per material. There are important differences in the color stability of the materials tested, which were mostly affected by the roughness parameters due to variations in their microstructure. © 2020 by the authors

Color stability and degree of cure of direct composite restoratives after accelerated aging

Purpose: This study evaluated the color changes and amount of remaining C=C bonds (%RDB) in three dental composites after hydrothermal- and photoaging. Methods and Materials: The materials tested were Estelite Σ, Filtek Supreme and Tetric Ceram. Specimens were fabricated from each material and subjected to L* a* b* colorimetry and FTIR spectroscopy before and after aging. Statistical evaluation of the ΔL,* Δa,* Δb,* ΔE and %ΔRDB data was performed by one-way ANOVA and Tukey's test. The %RDB data before and after aging were statistically analyzed using two-way ANOVA and Student-Newman-Keuls test. In all cases an α=0.05 significance level was used. Results: No statistically significant differences were found in ΔL*, Δa*, ΔE and %ΔRDB among the materials tested. Tetric Ceram demonstrated a significant difference in Δb*. All the materials showed visually perceptible (ΔE>1) but clinically acceptable values (ΔE<3.3). Within each material group, statistically significant differences in %RDB were noticed before and after aging (p<0.05). Filtek Supreme presented the lowest %RDB before aging, with Tetric Ceram presenting the lowest %RDB after aging (p<0.05). The %ΔRDB mean values were statistically significantly different among all the groups tested. No correlation was found between ΔE and %ΔRDB. © Operative Dentistry, 2007

Immediate dentin sealing: A literature review

Purpose: The immediate application of a dentin-bonding agent after tooth preparation and before impression-taking (immediate dentin sealing [IDS]) has been suggested to provide several advantages concerning bacterial microleakage, hypersensitivity, and bonding quality. We reviewed the literature and clarified certain aspects related to each step of IDS application. Materials and Methods: The search strategy comprised an electronic research in MEDLINE, Cochrane, Ovid and Scopus for studies published from January 1990 to December 2020 regarding the IDS technique and including both in vitro and clinical studies. Results: After exclusion of irrelevant or duplicate articles, 88 articles focusing on aspects of the IDS technique were assessed. IDS seems to be advantageous with regard to bond strength, gap formation, bacterial microleakage, and dentin hypersensitivity. However, issues arising from interaction with impression materials, the provisional phase, and conditioning methods before cementation require further investigation. Conclusion: There are no documented reasons preventing clinicians applying IDS in their everyday practice. On the contrary, the presented technique seems to be beneficial in certain aspects regarding indirect restorations. © 2021 Samartzi et al