scholarly journals In vivo wear of CAD-CAM composite versus lithium disilicate full coverage first-molar restorations: a pilot study over 2 years

2020 ◽  
Vol 24 (12) ◽  
pp. 4301-4311
Author(s):  
Jan-Frederik Güth ◽  
Kurt Erdelt ◽  
Christine Keul ◽  
Gintare Burian ◽  
Josef Schweiger ◽  
...  
Keyword(s):  
Wear Behavior ◽  
Lithium Disilicate ◽  
Tissue Loss ◽  
Invasive Treatment ◽  
Occlusal Contact ◽  
Wear Rates ◽  
Occlusal Wear ◽  
Cad Cam ◽  
Second Year

Abstract Objectives To present a digital approach to measure and compare material wear behavior of antagonistic first molar restorations made of an experimental CAD/CAM composite (COMP) and lithium disilicate ceramic (LS2) in patients with reconstructed vertical dimension of occlusion (VDO) after generalized hard tissue loss. Methods A total of 12 patients underwent complete full jaw rehabilitation with full occlusal coverage restorations made either of COMP or LS2. The first molar restorations (n = 48) were chosen for wear examination. At annual recall appointments, polyether impressions were taken, and resulting plaster casts were digitalized using a laboratory scanner. Mean observation period was 371 days for first and 769 days for second year. The resulting 96 datasets were analyzed by superimposition of 3-D datasets using an iterative best-fit method. Based on the superimposition data, the wear rates of the occlusal contact areas (OCAs) were calculated. Results For antagonistic restorations made of COMP, the average wear rate was 24.8 ± 13.3 μm/month, while for LS2, it was 9.5 ± 4.3 μm/month in first year, with significant differences (p < 0.0001) between the materials. In second year, monthly wear rates decreased significantly for both materials: COMP (16.2 ± 10.7 μm/month) and LS2 (5.5 ± 3.3 μm/month). Statistical comparison between wear time showed significant differences for both materials: COMP p < 0.037 and LS2 p < 0.001. A logarithmic fit (COMP R2 = 0.081; LS2 R2 = 0.038) of the data was calculated to estimate the wear progression. Significance In patients with reconstructed VDO, restorations made of LS2 show a more stable wear behavior than ones out of experimental CAD/CAM composite. In cases of complete rehabilitation, load bearing CAD/CAM-composite restorations should be critically considered for application due to their occlusal wear behavior. However, when choosing a restorative material, not only the functional occlusal stability should be taken into account but also the prospect of minimally invasive treatment with maximum preservation of natural tooth structures.

scholarly journals In-vivo-wear in composite and ceramic full mouth rehabilitations over 3 years

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gintare Burian ◽  
Kurt Erdelt ◽  
Josef Schweiger ◽  
Christine Keul ◽  
Daniel Edelhoff ◽  
...  
Keyword(s):  
Wear Rate ◽  
Tooth Wear ◽  
Occlusal Contact ◽  
Wear Rates ◽  
Recall Time ◽  
Cad Cam ◽  
The Mean ◽  
Posterior Restorations

AbstractThe aim of this study was to quantify and to compare the wear rates of premolar (PM) and molar (M) restorations of lithium disilicate ceramic (LS2) and an experimental CAD/CAM polymer (COMP) in cases of complex rehabilitations with changes in vertical dimension of occlusion (VDO). Twelve patients with severe tooth wear underwent prosthetic rehabilitation, restoring the VDO with antagonistic occlusal coverage restorations either out of LS2 (n = 6 patients, n = 16 posterior restorations/patient; N = 96 restorations/year) or COMP (n = 6 patients; n = 16 posterior restorations/patient; N = 96 restorations/year). Data was obtained by digitalization of plaster casts with a laboratory scanner at annual recalls (350 ± 86 days; 755 ± 92 days; 1102 ± 97 days). Each annual recall dataset of premolar and molar restorations (N = 192) was overlaid individually with the corresponding baseline dataset using an iterative best-fit method. Mean vertical loss of the occlusal contact areas (OCAs) was calculated for each restoration and recall time. For LS2 restorations, the mean wear rate per month over 1 year was 7.5 ± 3.4 μm (PM), 7.8 ± 2.0 μm (M), over 2 years 3.8 ± 1.6 µm (PM), 4.4 ± 1.5 µm (M), over 3 years 2.8 ± 1.3 µm (PM), 3.4 ± 1.7 µm (M). For COMP restorations, the mean wear rate per month over 1 year was 15.5 ± 8.9 μm (PM), 28.5 ± 20.2 μm (M), over 2 years 9.2 ± 5.9 µm (PM), 16.7 ± 14.9 µm (M), over 3 years 8.6 ± 5.3 µm (PM), 9.5 ± 8.0 µm (M). Three COMP restorations fractured after two years and therefore were not considered in the 3-year results. The wear rates in the LS2 group showed significant differences between premolars and molars restorations (p = 0.041; p = 0.023; p = 0.045). The wear rates in COMP group differed significantly between premolars and molars only in the first two years (p < 0.0001; p = 0.007). COMP restorations show much higher wear rates compared to LS2. The presented results suggest that with increasing time in situ, the monthly wear rates for both materials decreased over time. On the basis of this limited dataset, both LS2 and COMP restorations show reasonable clinical wear rates after 3 years follow-up. Wear of COMP restorations was higher, however prosthodontic treatment was less invasive. LS2 showed less wear, yet tooth preparation was necessary. Clinicians should balance well between necessary preparation invasiveness and long-term occlusal stability in patients with worn dentitions.

scholarly journals Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations

Medicina ◽  
2020 ◽  
Vol 56 (3) ◽  
pp. 132
Author(s):  
Georgina García-Engra ◽  
Lucia Fernandez-Estevan ◽  
Javier Casas-Terrón ◽  
Antonio Fons-Font ◽  
Pablo Castelo-Baz ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Fracture Resistance ◽  
Lithium Disilicate ◽  
Lithium Silicate ◽  
Control Group ◽  
Test Machine ◽  
Occlusal Wear ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam

Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 × 1.5 mm) from four test groups (N = 80; N = 20 per group): lithium disilicate (LDS) group (control group): IPS e.max CAD®; zirconium-reinforced lithium silicate (ZRLS) group: VITA SUPRINITY®; polymer-infiltrated ceramic networks (PICN) group: VITA ENAMIC®; resin nanoceramics (RNC) group: LAVA™ ULTIMATE. Each disc was cemented (following the manufacturers’ instructions) onto previously prepared molar dentin. Samples underwent until fracture using a Shimadzu® test machine. The stress suffered by each material was calculated with the Hertzian model, and its behavior was analyzed using the Weibull modulus. Data were analyzed with ANOVA parametric statistical tests. Results: The LDS group obtained higher fracture resistance (4588.6 MPa), followed by the ZRLS group (4476.3 MPa) and PICN group (4014.2 MPa) without statistically significant differences (p < 0.05). Hybrid materials presented lower strength than ceramic materials, the RNC group obtaining the lowest values (3110 MPa) with significant difference (p < 0.001). Groups PICN and RNC showed greater occlusal wear on the restoration surface prior to star-shaped fracture on the surface, while other materials presented radial fracture patterns. Conclusion: The strength of CAD-CAM materials depended on their composition, lithium disilicate being stronger than hybrid materials.

scholarly journals Can Pin-on-Disk Testing Be Used to Assess the Wear Performance of Retrieved UHMWPE Components for Total Joint Arthroplasty?

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Steven M. Kurtz ◽  
Daniel W. MacDonald ◽  
Sevi Kocagöz ◽  
Mariya Tohfafarosh ◽  
Doruk Baykal
Keyword(s):  
Wear Behavior ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Volumetric Wear ◽  
Wear Properties ◽  
Wear Rates ◽  
Ultrahigh Molecular Weight ◽  
Aging Conditions ◽  
Novel Method ◽  
Pin On Disk

The objective of this study was to assess the suitability of using multidirectional pin-on-disk (POD) testing to characterize wear behavior of retrieved ultrahigh molecular weight polyethylene (UHMWPE). The POD wear behavior of 25 UHMWPE components, retrieved after 10 yearsin vivo, was compared with 25 that were shelf aged for 10–15 years in their original packaging. Components were gamma sterilized (25–40 kGy) in an air or reduced oxygen (inert) package. 9 mm diameter pins were fabricated from each component and evaluated against CoCr disks using a super-CTPOD with 100 stations under physiologically relevant, multidirectional loading conditions. Bovine serum (20 g/L protein concentration) was used as lubricant. Volumetric wear rates were found to vary based on the aging environment, as well as sterilization environment. Volumetric wear rates were the lowest for the pins in the gamma inert, shelf aged cohort. These results support the utility of using modern, multidirectional POD testing with a physiologic lubricant as a novel method for evaluating wear properties of retrieved UHMWPE components. The data also supported the hypothesis that wear rates of gamma-inert liners were lower than gamma-air liners for both retrieved and shelf aging conditions. However, this difference was not statistically significant for the retrieved condition.

scholarly journals A COMPARATIVE STUDY ON WEAR BEHAVIOR OF HIP PROSTHESIS BY FINITE ELEMENT SIMULATION

2002 ◽  
Vol 14 (04) ◽  
pp. 139-148 ◽  
Author(s):  
JUI-PIN HUNG ◽  
JAMES SHIH-SHYN WU
Keyword(s):  
Hip Prosthesis ◽  
Polyethylene Wear ◽  
Wear Behavior ◽  
Numerical Approach ◽  
Analysis Model ◽  
Wear Rates ◽  
Femoral Heads ◽  
Artificial Hip Joints ◽  
Pin On Disk

A numerical approach was proposed to investigate the wear behavior occurred in the artificial hip joints in this paper. In the numerical simulations, the wear coefficients taken from pin-on-disk tests were introduced into the wear analysis model to assess the wear rates of polyethylene acetabular cups against metallic or ceramic femoral heads. For the established material combinations, different values of polyethylene wear rates were obtained respectively, which were not necessarily the realistic one as expected in vivo but could be confirmed after further discussion on the wear mechanism involved in wear tests. Current results indicated that the polyethylene/ceramic couples represented better wear performances than the polyethylene/metal couples. Furthermore, the ratio of wear rates for polyethylene cups against alumina and the metallic femoral heads was 0.5, which agreed well with that deduced from clinical studies or laboratory hip simulators. It is obvious that these comparable wear behaviors observed from clinics or laboratory studies also can be found by means of the numerical simulation.

Evaluation of bond strength of dual resin cements to CAD/CAM-created lithium disilicate ceramic

2020 ◽  
Vol 69 (3) ◽  
Author(s):  
Felipe Sczepanski ◽  
Cláudia R. Brunnquell ◽  
Sandrine B. Berger ◽  
Eloisa A. Paloco ◽  
Murilo B. Lopes ◽  
...  
Keyword(s):  
Bond Strength ◽  
Lithium Disilicate ◽  
Resin Cements ◽  
Cad Cam

(Preprint)

2018 ◽  
Author(s):  
Dr Malathi Dayalan ◽  
Dr Sudeshna Sharma ◽  
Dr Shweta Poovani ◽  
Dr Saher Altaf
Keyword(s):  
Myofascial Pain ◽  
Mouth Opening ◽  
Masticatory Muscles ◽  
Matched Pair ◽  
Masticatory Muscle ◽  
Muscle Disorders ◽  
Occlusal Contact ◽  
Group I ◽  
Group Ii

BACKGROUND Masticatory system is a complex functional unit, primarily engaged in chewing, swallowing and breathing functions, and some parts are involved in taste recognition and determination of food consistency. Sophisticated functional performances of speech and emotional expressions are specifically human qualities. Irregularities in occlusion appears to be the precipitating factor in the pathogenesis of myofascial pain dysfunction syndrome. Tek- Scan III records the bite length, number, distribution, timing, duration and the relative force of each tooth contact. It also records the sequence of occlusal contacts in terms of time and the associated force with each occlusal contact. The aim of this study was to treat masticatory muscle disorders with occlusal equilibration, and compare the efficacy of treatment outcomes between selective grinding and stabilization splints using Tek-Scan III. OBJECTIVE Objective of this study was to compare the efficacy of occlusal equilibration achieved through selective griding and stabilization splints using Tek-Scan III. METHODS In this in vivo study, 40 patients with masticatory muscle disorders were selected based on the inclusion and exclusion criteria. The occlusal discrepancies were analyzed using Tek-Scan III. The selected 40 subjects were then randomly divided into 2 groups based on the treatment they recieved; Group I – Selective grinding group (20) and Group II – Stabilization splint group (20). Comparison of pre-treatment and post treatment results were evaluated in terms of pain, mouth opening, left and right side force percentage as recorded through Tek-Scan III and reduction of disclusion time. Statistical analysis was carried out with Kolmogorov Smirnov test, Wilcoxon matched pair test and Mann-Whitney U test. RESULTS Wilcoxon matched pairs test demonstrated that there was statistically significant results ( p = 0.0007) in both the groups for reduction of disclusion time, elimination of pain and improved mouth opening. Patients in Group I showed better results as compared to Group II in terms of disclusion time, pain and mouth opening. CONCLUSIONS Occlusal equilibration brought about by reducing the disclusion time using the Tek- Scan III reduced the symptoms of pain in masticatory muscles. Patients in group I (Selective grinding) however showed better results when compared to patients in group II (Stabilization splints).

scholarly journals The One-Year In Vivo Comparison of Lithium Disilicate and Zirconium Dioxide Inlays

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3102
Author(s):  
Rini Behera ◽  
Lora Mishra ◽  
Darshan Devang Divakar ◽  
Abdulaziz A. Al-Kheraif ◽  
Naomi Ranjan Singh ◽  
...  
Keyword(s):  
Zirconium Dioxide ◽  
Clinical Performance ◽  
Lithium Disilicate ◽  
Study Groups ◽  
Resin Cement ◽  
Internal Surfaces ◽  
Colour Match ◽  
One Year ◽  
The One

The objective of the present study was to evaluate the one-year clinical performance of lithium disilicate (LD) and zirconium dioxide (ZrO2) class II inlay restorations. Thirty healthy individuals who met the inclusion criteria were enrolled for the study. The patients were randomly divided into two study groups (n = 15): LD (IPS e.max press) and ZrO2 (Dentcare Zirconia). In the ZrO2 group, the internal surfaces of the inlays were sandblasted and silanized with Monobond N (Ivoclar, Leichsteistein, Germany). In the LD group, the internal surfaces of the inlays were etched with 5% hydrofluoric acid. The ceramic inlays were cemented with self-cure resin cement (Multilink N). Clinical examinations were performed using modified United State Public Health Codes and Criteria (USPHS) after 2 weeks, 4 weeks, 6 months and 1 year. The one-year survival rate was evaluated. In total, one failure was observed in the ZrO2 group. The survival probability after 1 year for the ZrO2 inlays was 93%, and for the LD inlays was 100%, which was statistically insignificant. The differences between both groups for most USPHS criteria (except for colour match) were statistically insignificant. Within the imitations of the present study, the lithium disilicate- and zirconia dioxide-based inlays exhibited comparable clinical performances. However, the colour and translucency match was superior for the lithium disilicate restorations.

Theoretical evaluation of abrasive wear behavior of B4C/ FeCrC coating layer evaluated by a Taguchi approach

2020 ◽  
Vol 62 (7) ◽  
pp. 733-738 ◽  
Author(s):  
A. K. Gür ◽  
T. Yildiz ◽  
B. Icen
Keyword(s):  
Taguchi Method ◽  
Abrasive Wear ◽  
Arc Welding ◽  
Wear Behavior ◽  
Theoretical Evaluation ◽  
Wear Rates ◽  
Abrasive Wear Behavior ◽  
Coating Layers ◽  
Plasma Transferred Arc Welding ◽  
Aisi 430

Abstract In this study, B4C and FeCrC powders were alloyed on the surface of AISI 430 by a fusion process via plasma transferred arc welding. Mixtures of these powders at various amounts were used. The microstructure and wear behavior of the obtained coating layers were investigated. The wear behavior of the coating layers was planned using the Taguchi method. Abrasive wear mass loss results were optimized with the “smaller the better” control characteristic of the Taguchi method, and the results were analyzed graphically. The actual data obtained at the end of the study were formed by using an L16 (4 × 2, 2 × 2) mixed array, and the remaining wear rates were calculated with the help of theoretical formulas in order to obtain theoretical abrasive wear results.

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