Changes in marginal gap size of provisional resin crowns after occlusal loading and thermal cycling

2000 ◽  
Vol 84 (2) ◽  
pp. 139-148 ◽  
Author(s):  
David S. Ehrenberg ◽  
Saul Weiner
Keyword(s):  
Thermal Cycling ◽  
Gap Size ◽  
Marginal Gap

Factors Associated with Microleakage in Class II Resin Composite Restorations

10.2341/06-16 ◽  
2007 ◽  
Vol 32 (1) ◽  
pp. 60-66 ◽  
Author(s):  
S. Idriss ◽  
T. Abduljabbar ◽  
C. Habib ◽  
R. Omar
Keyword(s):  
Clinical Outcomes ◽  
Clinical Relevance ◽  
Resin Composite ◽  
Class Ii ◽  
Gap Size ◽  
Marginal Gap ◽  
Factors Associated ◽  
Composite Restorations ◽  
Placement Technique

Clinical Relevance Even though marginal gap size was not shown to be a direct predictor for the extent of microleakage in resin composite restorations, both material and placement technique appear to be important determinants in microleakage and, thus, probably in clinical outcomes.

scholarly journals Influence of Material Selection on the Marginal Accuracy of CAD/CAM-Fabricated Metal- and All-Ceramic Single Crown Copings

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Matthias Rödiger ◽  
Lea Schneider ◽  
Sven Rinke
Keyword(s):  
Material Selection ◽  
Design Parameters ◽  
Processing Route ◽  
Chromium Alloy ◽  
Gap Size ◽  
Marginal Gap ◽  
Average Maximum ◽  
Single Crown ◽  
Cad Cam ◽  
Group 2

This study evaluated the marginal accuracy of CAD/CAM-fabricated crown copings from four different materials within the same processing route. Twenty stone replicas of a metallic master die (prepared upper premolar) were scanned and divided into two groups. Group 1 (n=10) was used for a pilot test to determine the design parameters for best marginal accuracy. Group 2 (n=10) was used to fabricate 10 specimens from the following materials with one identical CAD/CAM system (GAMMA 202, Wissner GmbH, Goettingen, Germany): A = commercially pure (cp) titanium, B = cobalt-chromium alloy, C = yttria-stabilized zirconia (YSZ), and D = leucite-reinforced glass-ceramics. Copings from group 2 were evaluated for the mean marginal gap size (MeanMG) and average maximum marginal gap size (AMaxMG) with a light microscope in the “as-machined” state. The effect of the material on the marginal accuracy was analyzed by multiple pairwise comparisons (Mann–Whitney, U-test, α=0.05, adjusted by Bonferroni-Holmes method). MeanMG values were as follows: A: 46.92 ± 23.12 μm, B: 48.37 ± 29.72 μm, C: 68.25 ± 28.54 μm, and D: 58.73 ± 21.15 μm. The differences in the MeanMG values proved to be significant for groups A/C (p=0.0024), A/D (p=0.008), and B/C (p=0.0332). AMaxMG values (A: 91.54 ± 23.39 μm, B: 96.86 ± 24.19 μm, C: 120.66 ± 32.75 μm, and D: 100.22 ± 10.83 μm) revealed no significant differences. The material had a significant impact on the marginal accuracy of CAD/CAM-fabricated copings.

scholarly journals Effect of Cavity Disinfection with Chlorhexidine on Marginal Gap of Class V Composite Restorations Bonded with a Universal Adhesive Using Self-Etch and Etch-and-Rinse Bonding Strategy

2020 ◽  
Author(s):  
Soodabeh Kimyai ◽  
Narmin Mohammadi ◽  
Mahmoud Bahari ◽  
Elahe Pesyanian ◽  
Farhood Pesyanian
Keyword(s):  
Composite Resin ◽  
Gap Size ◽  
Marginal Gap ◽  
Universal Adhesive ◽  
Class V ◽  
Etch And Rinse ◽  
The Mean ◽  
Composite Resin Restorations ◽  
Self Etch ◽  
Resin Restorations

Objectives: This in-vitro study aimed to evaluate the effect of cavity disinfection with chlorhexidine (CHX) on marginal gaps of Class V composite resin restorations bonded with a universal adhesive using self-etch and etch-and-rinse bonding strategy. Materials and Methods: Sixty sound human premolars were randomly assigned to two groups (n=30): group 1 (CHX) and group 2 (no CHX). Each group was divided into two subgroups (n=15) according to the bonding strategy of the universal adhesive (self-etch or etch-and-rinse). Class V cavities were prepared on the buccal surfaces of the teeth. The occlusal and gingival margins of the cavities were placed in enamel and dentin, respectively. In the first and second subgroups of both groups, the All-Bond Universal adhesive was applied with self-etch and etch-and-rinse bonding strategy, respectively. After restoration and thermocycling, the samples were sectioned, and marginal gaps at the gingival margins were measured in micrometer (µm) under a stereomicroscope. Two-way analysis of variance (ANOVA) was used to compare marginal gaps between the groups and the subgroups. Results: The mean marginal gap size was significantly affected by cavity disinfection (P=0.001) and bonding strategy (P=0.002). However, the interaction effect of these two factors on the mean marginal gap size was not significant (P=0.79). Conclusion: The use of CHX resulted in larger marginal gaps at the gingival margins of Class V composite resin restorations. Irrespective of disinfection, the self-etch bonding strategy resulted in larger marginal gaps compared to the etch-and-rinse bonding strategy.

scholarly journals Effect of Base Metal Alloys Recasting on Marginal Integrity of Castable Crowns

2013 ◽  
Vol 14 (2) ◽  
pp. 255-258 ◽  
Author(s):  
Farshad Bajoghli ◽  
Saeid Nosouhian ◽  
Hamid Badrian ◽  
Hossein Goroohi ◽  
Amir Saberian ◽  
...  
Keyword(s):  
Base Metal ◽  
Metal Alloys ◽  
P Value ◽  
Gap Size ◽  
Base Metals ◽  
Marginal Gap ◽  
Marginal Integrity ◽  
Significant Difference ◽  
Group A ◽  
Group B

ABSTRACT Introduction Base metals have a wide use in casting methods. Sometimes they are reused in laboratories which may have an adverse effect on the restoration marginal integrity. This study aimed to investigate the effect of recasting of alloys on marginal integrity of restorations. Materials and methods Models with two types of finishing lines shoulder bevel 45° and shoulder 135° were produced and 15 wax copings were formed on each one of them. Each group containing 15 copings was divided into three subgroups A, B and C. Group A was casted with 100% new alloy, group B with 50% new and 50% recasted alloy and group C with 100% recasted alloy. Obtained metal copings were placed on dies and marginal gap size between restoration margin and the dies finishing line was measured using metric microscope and Moticam camera in four points, buccal, lingual, mesial and distal. Results A significant difference in mean marginal gap size exists among three types of alloys used (p-value = 0.036). A significant difference is observed between mean marginal gap size of two types of finishing lines for different alloys (p-value = 0.001). Conclusion Using 100% recasted alloy is not recommended for any of the two types of finishing lines. How to cite this article Bajoghli F, Nosouhian S, Badrian H, Goroohi H, Saberian A, Gadesi L. Effect of Base Metal Alloys Recasting on Marginal Integrity of Castable Crowns. J Contemp Dent Pract 2013;14(2):255-258.

scholarly journals Accuracy of optical scanning methods of the Cerec®3D system in the process of making ceramic inlays

2010 ◽  
Vol 67 (10) ◽  
pp. 812-818 ◽  
Author(s):  
Branka Trifkovic ◽  
Aleksandar Todorovic ◽  
Vojkan Lazic ◽  
Miroslav Draganjac ◽  
Nemanja Mirkovic ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Technological Development ◽  
Control Group ◽  
Gap Size ◽  
Marginal Gap ◽  
Optical Scanning ◽  
3D Cad ◽  
Ceramic Inlays ◽  
Cad Cam ◽  
Cerec 3D

Background/Aim. One of the results of many years of Cerec? 3D CAD/CAM system technological development is implementation of one intraoral and two extraoral optical scanning methods which, depending on the current indications, are applied in making fixed restorations. The aim of this study was to determine the degree of precision of optical scanning methods by the use of the Cerec?3D CAD/CAM system in the process of making ceramic inlays. Methods. The study was conducted in three experimental groups of inlays prepared using the procedure of three methods of scanning Cerec ?3D system. Ceramic inlays made by conventional methodology were the control group. The accuracy of optical scanning methods of the Cerec?3D system computer aided designcomputer aided manufacturing (CAD/CAM) was indirectly examined by measuring a marginal gap size between inlays and demarcation preparation by scanning electron microscope (SEM). Results. The results of the study showed a difference in the accuracy of the existing methods of scanning dental CAD/CAM systems. The highest level of accuracy was achieved by the extraoral optical superficial scanning technique. The value of marginal gap size inlays made with the technique of extraoral optical superficial scanning was 32.97 ? 13.17 ?. Techniques of intraoral optical superficial and extraoral point laser scanning showed a lower level of accuracy (40.29 ? 21.46 ? for inlays of intraoral optical superficial scanning and 99.67 ? 37.25 ? for inlays of extraoral point laser scanning). Conclusion. Optical scanning methods in dental CAM/CAM technologies are precise methods of digitizing the spatial models; application of extraoral optical scanning methods provides the hightest precision.

PENGARUH THERMAL CYCLING TERHADAP PERUBAHAN DIMENSI DAN STABILITAS WARNA BAHAN BASIS GIGI TIRUAN NILON TERMOPLASTIK

2015 ◽  
Vol 18 (3) ◽  
pp. 280-284
Author(s):  
Dwi Tjahyaning Putranti ◽  
Oktia Kiki Triana
Keyword(s):  
Thermal Cycling

Nilon termoplastik sebagai bahan basis gigi tiruan mulai menjadi pilihan perawatan. Salah satu sifat fisis nilontermoplastik yang menjadi perhatian dalam penggunaannya sebagai bahan basis gigi tiruan adalah stabilitas dimensi danstabilitas warna. Penggunaan basis gigi tiruan di rongga mulut dalam waktu tertentu akan mengakibatkan berbagaiperubahan sifat bahan. Salah satu metode yang dapat digunakan untuk mengevaluasi sifat suatu bahan yaitu thermalcycling. Sampel dibuat sesuai ADA No. 12 untuk uji perubahan dimensi dan ISO No. 1567 untuk uji stabilitas warna.Thermal cycling 70 cycles dan 300 cycles dilakukan pada masing-masing sampel perlakuan. Hasil uji dianalisismenggunakan uji ANOVA untuk mengetahui pengaruh thermal cycling terhadap perubahan dimensi dan stabilitas warnayang menunjukkan hasil signifikan (p < 0,05) dibandingkan kelompok kontrol, serta uji LSD yang menunjukkan terdapatperbedaan pengaruh thermal cycling terhadap perubahan dimensi dan stabilitas warna bahan basis gigi tiruan nilontermoplastik. Thermal cycling 70 cycle dan 300 cycle pada bahan basis gigi tiruan nilon termoplastik dapat meningkatkannilai perubahan dimensi dan menurunkan nilai stabilitas warna bahan basis gigi tiruan nilon termoplastik. Kesimpulan,penggunaan gigi tiruan selama 1 minggu dibandingkan 1 bulan menyebabkan perubahan dimensi semakin besar danberkurangnya stabilitas warna pada basis gigi tiruan nilon termoplastik.

Parallel Glide: A Fundamentally Different Type of Dislocation Motion in Ultrathin Metal Films

2003 ◽  
Vol 779 ◽  
Author(s):  
T. John Balk ◽  
Gerhard Dehm ◽  
Eduard Arzt
Keyword(s):  
Thermal Cycling ◽  
Grain Boundaries ◽  
Film Surface ◽  
Metal Films ◽  
Geometric Constraints ◽  
Film Stress ◽  
Diffusional Creep ◽  
Creep Model ◽  
Substrate Interface ◽  
Film Substrate

AbstractWhen confronted by severe geometric constraints, dislocations may respond in unforeseen ways. One example of such unexpected behavior is parallel glide in unpassivated, ultrathin (200 nm and thinner) metal films. This involves the glide of dislocations parallel to and very near the film/substrate interface, following their emission from grain boundaries. In situ transmission electron microscopy reveals that this mechanism dominates the thermomechanical behavior of ultrathin, unpassivated copper films. However, according to Schmid's law, the biaxial film stress that evolves during thermal cycling does not generate a resolved shear stress parallel to the film/substrate interface and therefore should not drive such motion. Instead, it is proposed that the observed dislocations are generated as a result of atomic diffusion into the grain boundaries. This provides experimental support for the constrained diffusional creep model of Gao et al.[1], in which they described the diffusional exchange of atoms between the unpassivated film surface and grain boundaries at high temperatures, a process that can locally relax the film stress near those boundaries. In the grains where it is observed, parallel glide can account for the plastic strain generated within a film during thermal cycling. One feature of this mechanism at the nanoscale is that, as grain size decreases, eventually a single dislocation suffices to mediate plasticity in an entire grain during thermal cycling. Parallel glide is a new example of the interactions between dislocations and the surface/interface, which are likely to increase in importance during the persistent miniaturization of thin film geometries.

Crack Density Evaluation in Carbon Fibre Reinforced Polymers Aged by Thermal Cycling

2016 ◽  
Vol 53 (3) ◽  
pp. 125-143
Author(s):  
S. González ◽  
M. González ◽  
J. Dominguez ◽  
F. Lasagni
Keyword(s):  
Carbon Fibre ◽  
Thermal Cycling ◽  
Crack Density ◽  
Reinforced Polymers ◽  
Carbon Fibre Reinforced Polymers ◽  
Density Evaluation
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