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Journal of the American Dental... Jan 2021Zirconia is a relatively new dental material used for indirect dental restorations. Little is known about how dental practitioners are using this material in their...
BACKGROUND
Zirconia is a relatively new dental material used for indirect dental restorations. Little is known about how dental practitioners are using this material in their practice.
METHODS
A survey on zirconia restorations was developed and administered electronically through e-mail communications to the American Dental Association Clinical Evaluators (ACE) Panel on August 31, 2020. Reminders were sent to nonrespondents, and the survey closed 2 weeks after the launch date.
RESULTS
When using zirconia for a restoration, respondents choose it to restore natural teeth (99%) more often than implants (76%). Almost all respondents (98%) use it for posterior crowns, whereas approximately two-thirds (61%) use it for anterior crowns. Restoration removal or replacement and shade matching and translucency were the top 2 cited disadvantages of zirconia, whereas most of the respondents (57%) cited flexural strength or fracture resistance as the biggest advantage. Fine diamonds and ceramic polishers are used most often to polish and adjust zirconia restorations, whereas coarse diamond rotary instruments and those made specifically for zirconia are most frequently used for removing these restorations. Compared with metal ceramic restorations, more than 50% of respondents experience debonding more often with zirconia restorations.
CONCLUSIONS
Dentists recognize the favorable fracture resistance and flexural strength properties of zirconia, and most use similar techniques when adjusting and removing this material. Removing these restorations and shade matching are a struggle for many.
PRACTICAL IMPLICATIONS
Dentists may benefit from tips on the best methods to remove, shade match, and adhesively bond zirconia restorations.
Topics: American Dental Association; Ceramics; Crowns; Dental Materials; Dental Porcelain; Dental Prosthesis Design; Dental Restoration Failure; Dental Stress Analysis; Dentists; Humans; Professional Role; Surveys and Questionnaires; United States; Zirconium
PubMed: 33250170
DOI: 10.1016/j.adaj.2020.10.012 -
The Journal of Prosthetic Dentistry Apr 2022Implant-supported fixed dental prostheses have been classified into screw-retained and cement-retained types, and each retaining type has complications. A novel...
STATEMENT OF PROBLEM
Implant-supported fixed dental prostheses have been classified into screw-retained and cement-retained types, and each retaining type has complications. A novel retentive cementless double crown (CLD) type of the implant-supported fixed prosthesis has been developed. CLD has air pockets in the intaglio surface of the crown and does not require cement or a screw hole. However, studies on the retention force and stress distribution of the system are lacking.
PURPOSE
The purpose of this in vitro study was to evaluate the retention force and stress distribution in the CLD system.
MATERIAL AND METHODS
The specimen comprised an implant, a titanium abutment, and a zirconia crown. Retention forces of 10 specimens of the CLD type were measured at no loading and after cyclic loading for 50, 100, 200, 600, 10 000, and 1 000 000 cycles by using a universal testing machine with a custom attachment device. Forty specimens of the stress distribution test were divided into 4 groups based on the retention type (cement-retained or CLD type) and load direction (vertical or oblique). Strain gauges were attached onto the buccal and lingual sides of the implant, and microstrain values were measured. One-way analysis of variance with the post hoc Tukey honestly significant difference test was performed on the retention force data, and the t test was performed to analyze the microstrain value data (α=.05).
RESULTS
Retention forces after 0, 50, 100, 200, 600, 10 000, and 1 000 000 load cycles were 18.12 ±6.16 N, 20.47 ±5.78 N, 19.79 ±6.61 N, 18.46 ±5.23 N, 19.60 ±6.93 N, 21.75 ±5.03 N, and 40.91 ±9.32 N, respectively, and after 1 000 000 cycles, the retention force was significantly higher than that of other load cycles (P<.05). The mean of maximum microstrain values under the vertical load were similar in the cement-retained type (buccal side, 834.96 ±53.69 μm/m; lingual side, 490.76 ±34.12 μm/m) and the CLD type (buccal side, 814.28 ±71.20 μm/m; lingual side, 479.10 ±30.74) (P>.05), and the mean of maximum microstrain values under the oblique load was also similar in the cement-retained type (buccal side, 1991.04 ±109.89 μm/m; lingual side, -2232.41 ±189.88) and the CLD type (buccal side, 1932.47 ±152.51 μm/m; lingual side, -2097.47 ±130.69 μm/m) (P>.05).
CONCLUSIONS
The CLD type had clinically acceptable retention during 1 000 000 load cycles and had a similar or better stress distribution capability than the cement-retained type.
Topics: Crowns; Dental Abutments; Dental Cements; Dental Implants; Dental Materials; Dental Prosthesis Retention; Dental Prosthesis, Implant-Supported; Dental Stress Analysis; Materials Testing
PubMed: 33386135
DOI: 10.1016/j.prosdent.2020.09.050 -
Journal of Prosthodontics : Official... Apr 2023To measure the flexural strength and Weibull characteristics of aged and nonaged printed interim dental material fabricated with different layer thickness. (Comparative Study)
Comparative Study
PURPOSE
To measure the flexural strength and Weibull characteristics of aged and nonaged printed interim dental material fabricated with different layer thickness.
MATERIAL AND METHODS
Bars (25×2×2 mm) were additively fabricated by using a polymer printer (Asiga Max) and an interim resin (Nexdent C&B MFH). Specimens were fabricated with the same printing parameters and postprocessing procedures, but with 7 different layer thickness: 50 (control or 50-G group), 10 (10-G group), 25 (25-G group), 75 (75-G group), 100 (100-G group), 125 (125-G group), and 150 μm (150-G group). Two subgroups were created: nonaged and aged subgroups (n = 10). A universal testing machine was selected to measure flexural strength. Two-parameter Weibull distribution values were computed. Two-way ANOVA and Tukey tests were selected for statistical evaluation of the data (α = 0.05).
RESULTS
Artificial aging methods (p < 0.001) were a significant predictor of the flexural strength computed. Aged specimens acquired less flexural strength than nonaged specimens. The Weibull distribution obtained the highest shape for nonaged 50-G and 75-G group specimens compared with those of other nonaged groups, while the Weibull distribution showed the highest shape for aged 125-G specimens.
CONCLUSIONS
The flexural strength of the additively fabricated interim material examined was not influenced by the layer thickness at which the specimens were fabricated; however, artificial aging techniques reduced its flexural strength. Aged specimens presented lower Weibull distribution values compared with nonaged specimens, except for the 125-G specimens.
Topics: Flexural Strength; Dental Materials; Materials Testing; Surface Properties; Stress, Mechanical; Printing, Three-Dimensional; Polymerization; Polymers
PubMed: 35924435
DOI: 10.1111/jopr.13582 -
Operative Dentistry Jul 2022The aim of this in vivo study was to evaluate the clinical one-year follow-up of a silica- and flouroapatite-reinforced glass carbomer filling material as compared to a...
OBJECTIVE
The aim of this in vivo study was to evaluate the clinical one-year follow-up of a silica- and flouroapatite-reinforced glass carbomer filling material as compared to a resin composite restorative material.
METHODS AND MATERIALS
In this study, a total of 100 restorations were performed. Caries were removed conventionally with diamond burs. Half of the restorations were restored with nanocomposite resin (TEP) (Tokuyama Estelite, Tokuyama Dental, Japan) and the other half were restored with glass carbomer (GC) material (GCP Dental, The Netherlands). Each restorative material was applied according to the manufacturer's instructions. Restorations were evaluated with modified USPHS criteria at the end of the first week, 6 months, and 12 months. Data were analyzed using Fisher's Exact Chi-Square test, Fisher Freeman Halton Test, and Continuity (Yates) Correction. The Wilcoxon sign test was used for intra-group comparisons of the parameters.
RESULTS
When the filling materials were compared with one another, a statistically significant difference was observed in the 12th month on the marginal discoloration. A statistically significant difference was observed between the two materials in the 6th month on the marginal adaptation (p<0.05).
CONCLUSIONS
In view of these results, there is a need to improve the physical properties of the GC filling material in further in vivo studies.
Topics: Acrylic Resins; Color; Composite Resins; Dental Caries; Dental Marginal Adaptation; Dental Materials; Dental Restoration, Permanent; Follow-Up Studies; Glass Ionomer Cements; Humans; Surface Properties
PubMed: 36001813
DOI: 10.2341/21-016-C -
Investigative Radiology Sep 2023The aim of this study was to compare the effectiveness of common strategies for artifact reduction of dental material in photon-counting detector computed tomography...
Artifact Reduction From Dental Material in Photon-Counting Detector Computed Tomography Data Sets Based on High-keV Monoenergetic Imaging and Iterative Metal Artifact Reduction Reconstructions-Can We Combine the Best of Two Worlds?
OBJECTIVE
The aim of this study was to compare the effectiveness of common strategies for artifact reduction of dental material in photon-counting detector computed tomography data sets.
MATERIALS AND METHODS
Patients with dental material who underwent clinically indicated CT of the neck were enrolled. Image series were reconstructed using a standard and sharp kernel, with and without iterative metal artifact reduction (IMAR) (Qr40, Qr40 IMAR , Qr60, Qr60 IMAR ) at different virtual monoenergetic imaging (VMI) levels (40-190 keV). On representative slice positions with and without dental artifacts, mean and standard deviation of CT values were measured in all series at identical locations. The mean absolute error of CT values ( ) and the artifact index (AIX) were calculated and analyzed focusing on 3 main comparisons: ( a ) different VMI levels versus 70 keV, ( b ) standard versus sharp kernel, and ( c ) nonuse or use of IMAR reconstruction. The Wilcoxon test was used to assess differences for nonparametric data.
RESULTS
The final cohort comprised 50 patients. Artifact measures decreased for VMI levels >70 keV, yet only significantly so for reconstructions using IMAR (maximum reduction, 25%). The higher image noise of the sharp versus standard kernel is reflected in higher AIX values and is more pronounced in IMAR series (maximum increase, 38%). The most profound artifact reduction was observed for IMAR reconstructions (maximum reduction : 84%; AIX: 90%).
CONCLUSIONS
Metal artifacts caused by large amounts of dental material can be substantially reduced by IMAR, regardless of kernel choice or VMI settings. Increasing the keV level of VMI series, on the other hand, only slightly reduces dental artifacts; this effect, however, is additive to the benefit conferred by IMAR reconstructions.
Topics: Humans; Artifacts; Metals; Tomography, X-Ray Computed; Neck; Dental Materials; Algorithms
PubMed: 36897803
DOI: 10.1097/RLI.0000000000000967 -
Journal of Biochemical and Molecular... Sep 2021Curcumin (CUR) is an ancient therapeutic agent with remarkable antimicrobial and anti-inflammatory properties. The purpose of the current study was to synthesize and...
Curcumin (CUR) is an ancient therapeutic agent with remarkable antimicrobial and anti-inflammatory properties. The purpose of the current study was to synthesize and evaluate a curcumin-based reparative endodontic material to reduce infection and inflammation besides the induction of mineralization during the healing of the dentin-pulp complex. Poly-ɛ-caprolactone (PCL)/gelatin (Gel)/CUR scaffold was synthesized and assessed by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermo-gravimetric analysis (TGA). Agar diffusion test was performed against E. coli, A. baumannii, P. aeruginosa, S. aureus, E. faecalis, and S. mutans. Moreover, proliferative, antioxidative, anti-inflammatory, and calcification properties of these scaffolds on human dental pulp stem cells (hDPSCs) were evaluated. The results showed that PCL/Gel/CUR scaffold had antibacterial effects. Also, these CUR-based scaffolds had significant inhibitory effects on the expression of tumor necrosis factor α and DCF from inflamed hDPSCs (p < 0.05). Moreover, the induction of mineralization in hDPSCs significantly increased after seeding on CUR-based scaffolds (p < 0.05). Based on these findings, the investigated CUR-loaded material was fabricated successfully and provided an appropriate structure for the attachment and proliferation of hDPSCs. It was found that these scaffolds had antimicrobial, antioxidant, and anti-inflammatory characteristics and could induce mineralization in hDPSCs, which is essential for healing and repairing the injured dentin-pulp complex.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Biocompatible Materials; Curcumin; Dental Materials; Drug Evaluation, Preclinical; Humans; Materials Testing; Swine; Tissue Scaffolds
PubMed: 34331815
DOI: 10.1002/jbt.22854 -
Journal of Prosthodontic Research Jan 2022The purpose of this study was to examine the wear of resin materials using two-body wear tests and to verify a selection method for optimal interim restoration materials...
PURPOSE
The purpose of this study was to examine the wear of resin materials using two-body wear tests and to verify a selection method for optimal interim restoration materials from findings of a diagnostic occlusal device.
METHODS
Specimens were prepared from nine different resins used for diagnostic occlusal devices (soft resin) and interim restorations. Wear tests were conducted using an abrasion testing machine. The resulting wear on resin specimens and antagonist stainless-steel styluses was measured using a laser confocal scanning microscope, and the surface conditions were observed through a scanning electron microscope. The data were analyzed with one-way ANOVA and Tukey's multiple comparison test. The findings of the previous study on diagnostic occlusal devices were referred to in order to verify the selection method of optimal interim restoration materials.
RESULTS
The maximum wear depth of the soft resin specimens was significantly greater than that of the other specimens (p<0.05) and was equivalent to the wear depth of a diagnostic occlusal device used for 14 nights. The wear of bis-acryl resin material was shallower than that of the other materials (Polymethyl methacrylate and polyethyl methacrylate), and its antagonist stylus was significantly worn (p<0.05).
CONCLUSION
The findings of the previous and present studies showed a relationship among the parameters of Electromyography, wear depth of the diagnostic occlusal device, and wear of materials used for interim restorations. Findings related to bruxism can guide in the selection of interim restoration material and the determination of a suitable duration of wear.
Topics: Composite Resins; Dental Materials; Dental Restoration Wear; Materials Testing; Surface Properties
PubMed: 34321371
DOI: 10.2186/jpr.JPR_D_20_00103 -
Operative Dentistry May 2024
Topics: Humans; Dentistry, Operative; Dental Materials
PubMed: 38807320
DOI: 10.2341/1559-2863-49-3-245 -
The Journal of Prosthetic Dentistry Nov 2022The influence of postpolymerization methods and artificial aging procedures on the fracture resistance and flexural strength of additively manufactured interim polymers...
STATEMENT OF PROBLEM
The influence of postpolymerization methods and artificial aging procedures on the fracture resistance and flexural strength of additively manufactured interim polymers remains unclear.
PURPOSE
The purpose of this in vitro study was to evaluate the effect of the conditions (dry and water- and glycerin-submerged) and time (25, 30, 35, 40, and 45 minutes) of postpolymerization methods with and without artificial aging procedures on the fracture resistance and flexural strength of an additively manufactured interim material.
MATERIAL AND METHODS
Bar specimens (25×2×2 mm) were manufactured from an interim resin (NexDent C&B MFH N1) with a 3-dimensional printer (NexDent 5100) as per the manufacturer's recommendations. Three groups were created based on the postpolymerization condition: dry (D group) and submerged in a container with water (W group) or glycerin (G group) inside the ultraviolet polymerization machine (LC-3DPrint Box). Each group was divided into 5 subgroups (D1 to D5, W1 to W5, and G1 to G5) depending on the polymerizing time (25, 30, 35, 40, and 45 minutes) (n=20). Each subgroup was divided into nonaged and aged subgroups. The aged groups were treated in a mastication simulator. Fracture strength was measured on a universal testing machine. The flexural strength was calculated as per International Organization for Standardization (ISO) 10477-2018. The Kolmogorov-Smirnov test demonstrated that data were normally distributed. The 3-way ANOVA test was used to analyze the data (α=.05).
RESULTS
A significant main effect was found on the fracture strength analysis for each of the 3 factors: postpolymerization condition (F[2, 449]=81.00, P<.001), treatment duration (F[4, 449]=2.84, P=.024), and aging procedure (F [1, 449] =7.62, P=.006). The only significant 2-way interaction was between postpolymerization condition and treatment duration (F[8, 449]=3.12, P=.002). Furthermore, a significant main effect was found on the flexural strength for each of the 3 factors including postpolymerization condition (F[2, 449]=82.55, P<.001), treatment duration (F[4, 449]=2.85, P=.024), and artificial aging procedure (F[1, 449]=6.72, P=.010). The only significant 2-way interaction was between postpolymerization condition and treatment duration (F[8, 449]=3.33, P=.001). Dry postconditions at 25 minutes and nonaged procedures obtained the significantly highest fracture resistance and flexural strength values.
CONCLUSIONS
Postpolymerization conditions and duration time affected the fracture resistance and flexural strength of the additively manufactured interim material assessed. Artificial aging procedures significantly decreased the fracture resistance and flexural strength of the additively manufactured interim dental material.
Topics: Flexural Strength; Polymerization; Dental Materials; Materials Testing; Glycerol; Water; Dental Stress Analysis; Pliability
PubMed: 33795163
DOI: 10.1016/j.prosdent.2021.02.017 -
Journal of Esthetic and Restorative... Jun 2021Bulk-fill materials can facilitate the restorative procedure mainly for deep and wide posterior cavities. The purpose of this study was to evaluate flexural strength...
BACKGROUND
Bulk-fill materials can facilitate the restorative procedure mainly for deep and wide posterior cavities. The purpose of this study was to evaluate flexural strength (biaxial flexural strength [BFS]) and microhardness (Knoop microhardness [KHN]) at different depths of bulk-fill materials.
METHODS
Five bulk-fill materials were tested: two light-curable composite resins, one dual-cure composite, one bioactive restorative, and a high-viscosity glass ionomer. A conventional composite was used as control. BFS and KHN were tested at different depths. Data was analyzed by two- and one-way ANOVAs, respectively and Tukey's post-hoc (α=0.05).
RESULTS
The high-viscosity glass ionomer material presented the lowest BFS at all depths. KHN for the two light-curable and the dual-cure bulk-fill resin composites was reduced following an increase in restoration depth, while the conventional composite, the bioactive material, and the high-viscosity glass ionomer were not affected.
CONCLUSION
There are differences in the properties of the tested materials at 4 mm depth, showing that the studied properties of some materials vary according to the cavity depth, although the results are material dependent.
CLINICAL SIGNIFICANCE
Mechanical properties of light-cured, bulk-fill materials may be affected by inadequate polymerization. Clinicians should consider complementary strategies to achieve adequate polymerization at high-increment depths.
Topics: Composite Resins; Dental Materials; Flexural Strength; Materials Testing; Polymerization
PubMed: 33675162
DOI: 10.1111/jerd.12727