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Journal of Dentistry Sep 2023The purpose of this in vitro study was to evaluate the microstructural, elemental and mechanical properties of contemporary computer-aided-design/computer-aided...
OBJECTIVES
The purpose of this in vitro study was to evaluate the microstructural, elemental and mechanical properties of contemporary computer-aided-design/computer-aided manufacturing (CAD/CAM) resin based composite (RBC) materials.
METHODS
Six CAD/CAM RBC materials [Brilliant CRIOS (Coltene Whaledent AG), Cerasmart (GC), Lava Ultimate (3M ESPE), Tetric CAD (Ivoclar Vivadent), Shofu Block HC (Shofu), Grandio Blocs (VOCO GmbH)] were tested. Ten rectangular blocks (14 Χ 12 Χ 18 mm) for each material, after metallographic grinding and polishing, were subjected to Instrumented Indentation Testing (ΙIT). Martens Hardness (HM), Indentation Elastic Modulus (E), Elastic (η) and Creep indices (C) were determined according to formulas provided by ISO 14577. The diagonal length of each indentation was measured and HV was determined. The results of HM, E, η, HV, and C were statistically analyzed by one-way ANOVA and Tukey post hoc test employing the material as a discriminating variable (a = 0.05), while the possible correlations were determined by Spearman's correlation test. One specimen from each group was examined by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).
RESULTS
Backscattered Electron images and EDX analysis demonstrated differences in size, shape and type of fillers along with elemental composition among materials tested. Statistical significant differences were identified for all mechanical properties tested. Grandio Blocs had the significantly higher HM (953±7 N/mm), HV (136±1) and E (23±1 GPa) followed by Lava Ultimate (ΗM=674±25 N/mm, HV=105±2, E=15±1 GPa). Elastic index ranged from 41% to 52%, with Shofu Block demonstrating the significantly highest η (52 ± 1%) values. Cerasmart had significantly higher C value (8.4 ± 0.1%) than all other materials tested, while Grandio Blocs and Lava Ultimate had the lowest ones. Spearman's correlation revealed that all mechanical properties tested exhibited correlations with each other, apart from η.
CONCLUSIONS
The results showed that the CAD/CAM materials tested have differences in their microstructure, elemental composition and mechanical properties.
CLINICAL SIGNIFICANCE
The RBCs tested showed significant differences in mechanical properties and thus differences in clinical performance are anticipated. RBCs with increased filler loading had the most favorable combination of hardness, elastic modulus and creep index indicating that these materials may have better clinical performance under intraoral loading conditions.
Topics: Materials Testing; Composite Resins; Dental Materials; Computer-Aided Design; Hardness; Elastic Modulus; Surface Properties; Ceramics
PubMed: 37459951
DOI: 10.1016/j.jdent.2023.104623 -
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 -
International Dental Journal Oct 2023This study aimed to evaluate the fracture resistance and stress magnitude of occlusal veneers made of conventional or flowable resin composites at different minimal...
PURPOSE
This study aimed to evaluate the fracture resistance and stress magnitude of occlusal veneers made of conventional or flowable resin composites at different minimal thicknesses bonded on enamel or dentin.
MATERIAL AND METHODS
A total of 120 sound bovine incisors were flattened and used as substrates (enamel or dentin) for the restorations. The teeth were embedded into polymethyl methacrylate and allocated into 4 groups according to the resin composite (Clearfil AP-X PLT and Clearfil Majesty Flow, Kuraray Dental) and substrate. Further, the substrates were randomly subdivided in 12 groups (N = 120, n = 10) according to the occlusal veneer minimal thickness: 0.5, 1.0, or 2.0 mm. The teeth were directly restored with a standardised procedure. Then, the specimens were loaded until fracture in a universal testing machine (Instron 6022, Instron Corp.). A 3-way and a 1-way analysis of variance were used to determine significant differences for each factor. Three-dimensional finite element analysis was carried out following the in vitro boundary conditions to assess the stress magnitude in the restoration during compressive loading.
RESULTS
The fracture loads were recorded into initial load to failure (ILF) and fatal load to failure (FLF). Differences were found in material for ILF and FLF, leading to an overall equal good performance in fracture load and stress distribution for both materials, regardless of the substrate. Differences in thickness were apparent in both ILF and FLF.
CONCLUSIONS
Direct conventional and flow resin composite occlusal veneers present a promising mechanical behaviour when bonded on enamel or dentin. However, caution is advised when preparing 0.5-mm minimal thickness restorations.
Topics: Animals; Cattle; Composite Resins; Dental Enamel; Dental Porcelain; Dental Restoration Failure; Materials Testing
PubMed: 36509557
DOI: 10.1016/j.identj.2022.11.006 -
Operative Dentistry May 2024
Topics: Humans; Dentistry, Operative; Dental Materials
PubMed: 38807320
DOI: 10.2341/1559-2863-49-3-245 -
Odontology Oct 2023Titanium and its alloys are the preferred materials for medical implants. However, easy infection is a fatal shortcoming of Ti implants. Fortunately, the ongoing... (Review)
Review
Titanium and its alloys are the preferred materials for medical implants. However, easy infection is a fatal shortcoming of Ti implants. Fortunately, the ongoing development of antibacterial implant materials is a promising solution, and Ti alloys with antibacterial properties hold immense potential for medical applications. In this review, we briefly outline the mechanisms of bacterial colonization and biofilm formation on implants; discuss and classify the major antimicrobials currently in use and development, including inorganic and organic antimicrobials; and describe the important role of antimicrobials in the development of implant materials for clinical applications. Strategies and challenges related to improving the antimicrobial properties of implant materials as well as the prospects of antibacterial Ti alloys in the medical field are also discussed.
Topics: Titanium; Alloys; Materials Testing; Staphylococcus aureus; Dental Implants; Anti-Bacterial Agents; Dental Materials; Surface Properties
PubMed: 37402971
DOI: 10.1007/s10266-023-00832-x -
Journal of Dental Education Sep 2023To identify behavioral, preferential, and professional factors influencing the use of amalgam in private practices; and to compare the incidence of the placement of...
OBJECTIVES
To identify behavioral, preferential, and professional factors influencing the use of amalgam in private practices; and to compare the incidence of the placement of amalgam versus composite resin restorations in the province of Ontario and its pedagogical implications on dental curricula.
METHODS
Participants responded anonymously to a 23-question online survey about their current use of dental amalgam and composite resins as well as their opinions regarding both dental materials. The explanatory variables were associated bivariately with the outcome variables, and the most significant predictors were identified using the multivariate analysis.
RESULTS
Higher percentages of amalgam use were reported among clinicians who trained in Canada only (P = .009), who graduated before 1980 (p = <.001) and who work outside private practice (p = <.001). Familiarity with amalgam was higher among clinicians who are female (p = <.001), older (p = <.001), trained only in Canada (p = .017), who graduated prior to 2000 (p = <.001), and who work in locations with populations over 100,000 (p = .042). Familiarity with composite resin was higher among clinicians who graduated more recently (p = .002). A higher percentage of females (p = <.001), younger clinicians (p = <.001), recent graduates (p = <.001), and clinicians who work in private practice (p = .043) suggested that over 50% of dental student training time be allocated to amalgam.
CONCLUSIONS
Decreased amalgam use was reported by later dental graduates and private practitioners; this may be impacted by familiarity with dental amalgam. As amalgam remains a safe and effective dental material, its removal may not be prudent. Dental educators play a crucial role in the future of amalgam opinion and use.
Topics: Humans; Female; Male; Dental Restoration, Permanent; Dental Amalgam; Composite Resins; Curriculum; Education, Dental
PubMed: 37280767
DOI: 10.1002/jdd.13252 -
Journal of the Mechanical Behavior of... Dec 2023This study investigated the impact of preparation design and material types on fracture strength in maxillary premolars endocrowns after thermodynamic aging.
PURPOSE
This study investigated the impact of preparation design and material types on fracture strength in maxillary premolars endocrowns after thermodynamic aging.
MATERIALS AND METHODS
Eighty two-rooted maxillary premolar crowns underwent endodontic treatment (N = 80, n = 10). The teeth were categorized into ten groups (4-mm deep with no intracanal extension lithium disilicate glass ceramic & multilayer zirconia endocrowns (LE0 & ZE0); 4-mm deep with 4-mm intracanal extension in one canal (LE1 & ZE1); 4-mm deep with 2-mm intracanal extensions in both canals (LE2 & ZE2); flat overlays with no endocore (LO & ZO); glass fiber reinforced post & core and crown (LC & ZC)). After cementation, all specimens were subjected to 1500 thermocycles and 1,200,000 chewing cycles with an axial occlusal load of 49 N. A static loading test was performed at a non-axial 45° loading using a universal testing machine and failure modes (Type I: restoration debonding; Type II: restoration fracture; Type III: restoration/tooth complex fracture above bone level; Type IV: restoration/tooth complex fracture below bone level) were evaluated using a stereoscope. Data were ananalzed using 2-way ANOVA and Tukey's tests (alpha = 0.05).
RESULTS
The endocrowns manufactured from multilayered zirconia and pressed lithium disilicate glass ceramic exhibited a fracture load ranging between 1334 ± 332 N and 756 ± 150 N, with ZC presenting the highest and LE2 the lowest values. The differences were not statistically significant (p > 0.05).
CONCLUSION
All endocrowns tested in this study performed similar considering the different designs and materials tested. The distribution of fracture modes did not differ significantly depending on the design of the restoration and the type of material used.
Topics: Humans; Flexural Strength; Materials Testing; Computer-Aided Design; Zirconium; Ceramics; Dental Porcelain; Tooth Fractures; Dental Stress Analysis; Dental Restoration Failure
PubMed: 37839334
DOI: 10.1016/j.jmbbm.2023.106184 -
BMC Oral Health Jul 2023This study aims to evaluate the primary teeth undergoing amputation due to dental caries or trauma clinically and radiologically.
AIM
This study aims to evaluate the primary teeth undergoing amputation due to dental caries or trauma clinically and radiologically.
MATERIAL AND METHODS
The amputation treatment of 90 primary teeth of 58 patients (Female: 20, Male: 38) aged 4-11 years was evaluated clinically and radiologically. Calcium Hydroxide was used for amputation in this study. Composite or amalgam was preferred as filling material in the same session of the patients. Clinical/radiological (Periapical/Panoramic X-ray) examination was performed on the teeth that were unsuccessful in treatment, on the day of the patient's complaint, and at the end of 1 year in the others.
RESULTS
According to the clinical and radiological findings of the patients, 14.4% of the boys and 12.3% of the girls were unsuccessful. Amputation in male was a need in the 6-7 age group with a rate of 44.6% at most. Amputation in females was a need in the 8-9 age group with a rate of 52% at most.
CONCLUSION
Success in amputation treatment depends on the tooth, the dentist, and the dental material applied.
Topics: Humans; Male; Female; Child; Dental Caries; Tooth, Deciduous; Dental Materials; Calcium Hydroxide; Dental Amalgam
PubMed: 37415166
DOI: 10.1186/s12903-023-03171-z -
American Journal of Dentistry Aug 2023To evaluate and compare the effects of different scaling and polishing techniques on the surface roughness of four different restorative materials.
PURPOSE
To evaluate and compare the effects of different scaling and polishing techniques on the surface roughness of four different restorative materials.
METHODS
72 specimens were prepared, molded to a size of 8.0 by 2.0 mm, and cured according to the manufacturers' instructions. The specimens were stored at 37°C for 24 hours and then thermocycled for 5,000 cycles (from 55°C to 5°C) to simulate 6 months of clinical use. Surface roughness (Ra/average and Rz/max-overall heights) was calculated using a stylus profilometer by subtracting the simulated treatments of hand scaling, ultrasonic scaling, and air polishing from the baseline measurements. The difference in Ra and Rz data were compared independently for each measurement using a two-way ANOVA on Ranks and the Holm-Sidak test, with α< 0.05 used to determine significance.
RESULTS
Irrespective of the scaling or polishing technique employed, flowable bulk fill demonstrated the lowest Ra and Rz values. Hand scaling exhibited the highest roughness and variability among the other techniques, regardless of the materials tested (P< 0.001). Air polishing with glycine resulted in the lowest roughness values across all tested materials, with the exception of the tested bioactive restorative material group.
CLINICAL SIGNIFICANCE
Regarding surface roughness, air polishing with glycine may be an effective and safe intervention for periodontal maintenance of subgingival restorations compared to the other tested scaling methods.
Topics: Dental Scaling; Analysis of Variance; Dental Materials; Glycine; Ultrasonics
PubMed: 37587032
DOI: No ID Found -
European Journal of Oral Sciences Jun 2024This study aimed at examining the bond strength between zirconia and ceramic veneer, following the ISO 9693 guidelines. A total of fifty specimens of...
This study aimed at examining the bond strength between zirconia and ceramic veneer, following the ISO 9693 guidelines. A total of fifty specimens of zirconia/ceramic-veneer system were produced using two commercial zirconias (VITA YZ-HT and Zolid HT+ White, referred to as Group A and Group B, respectively) and a ceramic-veneering material (Zirkonia 750). The microstructure (via x-ray diffraction analysis, XRD and Secondary Electron mode, SEM) and the mechanical properties (via 3-point bending tests) of the two groups were assessed. Then, experiments were conducted according to the ISO 9693 and conventional protocols applied for producing zirconia/ceramic-veneer restorations. Bond strength values, measured by 3-point bending tests, were 34.42 ± 7.60 MPa for Group A and 31.92 ± 6.95 MPa for Group B. SEM observations of the cohesively fractured surfaces (on the porcelain side) and the examination for normality using the Shapiro-Wilk test suggested the use of Weibull statistical analysis. Median strength (σ) for Group A and Group B was 34.76 and 32.22 MPa, while the characteristic strength (σ) was 35.78 and 33.14 MPa, respectively. The Weibull modulus disparity between groups (12.69 and 13.07) was not significant. Bond strength exceeded the ISO 9693 minimum of 20 MPa, suggesting satisfactory strength for clinical use.
Topics: Zirconium; Dental Veneers; Dental Porcelain; Materials Testing; Dental Bonding; Dental Stress Analysis; X-Ray Diffraction; Microscopy, Electron, Scanning; Surface Properties; Ceramics; Dental Materials; Humans
PubMed: 38679835
DOI: 10.1111/eos.12989