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British Dental Journal Jan 2022This is the first part of a six-part series exploring the main ceramic materials used for the fabrication of all-ceramic, indirect restorations to aid clinicians in...
This is the first part of a six-part series exploring the main ceramic materials used for the fabrication of all-ceramic, indirect restorations to aid clinicians in their selection. We have detailed the history of how dental ceramics were introduced and how they have been revolutionised with the help of improvements within technology and understanding of the material. Dental ceramics can be classified in a few ways. One way is according to their ratio of glass to crystalline content and the other is how it is processed. Having a good in-depth understanding of this will allow clinicians to make the best decision for their patients who require ceramic restorations. This article aims to explore all the above to aid clinicians in making that decision.
Topics: Ceramics; Dental Materials; Dental Porcelain; Glass; Humans
PubMed: 35031736
DOI: 10.1038/s41415-021-3818-x -
Scanning 2020Hydroxyapatite nanoparticles (nano-HAP) are receiving considerable attention for dental applications, and their adhesion to enamel is well established. However, there...
Hydroxyapatite nanoparticles (nano-HAP) are receiving considerable attention for dental applications, and their adhesion to enamel is well established. However, there are no reports concerning the effects of HAP on other dental materials, and most of the studies in this field are based on designs, neglecting the salivary pellicle-apatite interactions. Thus, this pilot study aims to evaluate the effects of three hydroxyapatite-based solutions and their interactions with different dental material surfaces under oral conditions. Hence, two volunteers carried intraoral splints with mounted samples from enamel and from three dental materials: titanium, ceramics, and polymethyl-methacrylate (PMMA). Three HAP watery solutions (5%) were prepared with different shapes and sizes of nano-HAP (HAP I, HAP II, HAP III). After 3 min of pellicle formation, 10 ml rinse was performed during 30 sec. Rinsing with water served as control. Samples were accessed immediately after rinsing, 30 min and 2 h after rinsing. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the particles, and SEM evaluated the pellicle-HAP interactions. SEM and TEM results showed a high variation in the size range of the particles applied. A heterogeneous HAP layer was present after 2 h on enamel, titanium, ceramics, and PMMA surfaces under oral conditions. Bridge-like structures were visible between the nano-HAP and the pellicle formed on enamel, titanium, and PMMA surfaces. In conclusion, nano-HAP can adhere not only to enamel but also to artificial dental surfaces under oral conditions. The experiment showed that the acquired pellicle act as a bridge between the nano-HAP and the materials' surface.
Topics: Adult; Bacterial Adhesion; Ceramics; Dental Materials; Durapatite; Female; Humans; Male; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanoparticles; Pilot Projects; Surface Properties; Titanium; Tooth Erosion
PubMed: 32454927
DOI: 10.1155/2020/6065739 -
Surface characterization of indirect restorative materials submitted to different etching protocols.Journal of Dentistry Dec 2022This in vitro study aimed to evaluate the effect of different times and concentrations of hydrofluoric acid etching on the surface of indirect restorative materials...
OBJECTIVES
This in vitro study aimed to evaluate the effect of different times and concentrations of hydrofluoric acid etching on the surface of indirect restorative materials obtained from blocks used in CAD-CAM technology.
METHODS
Specimens (4 mm × 4 mm × 0.8 mm) were obtained for each indirect restorative material: zirconia-reinforced lithium monosilicate ceramic (Celtra Duo), nanoceramic resin (Lava Ultimate), and polymer-infiltrated ceramic network material (Vita Enamic). The materials were submitted to etching with 5% or 10% hydrofluoric acid for 20, 40, 60, or 90 s. A control group for each material was evaluated without any surface treatment, totaling nine experimental groups for each material (n = 10). The specimens were evaluated for surface roughness (R and R), confocal optical microscopy, the contact angle (θ), surface free energy (γs), total free interaction energy (∆G) using a goniometer, and microshear bond strength to resin cement. Specimen images were obtained using scanning electron microscopy, confocal optical microscopy, and atomic force microscopy. Data on the surface roughness, the contact angle, surface free energy, total free interaction energy, and bond strength were subjected to two-way ANOVA and Tukey´s test (α=0.05).
RESULTS
In general, Celtra Duo showed better results after etching with 10% hydrofluoric acid for 40 or 60 s. Lava Ultimate showed better performance after etching with 10% hydrofluoric acid for 20 or 40 s, whereas Vita Enamic showed better results after etching with 5% hydrofluoric acid for 90 s.
CONCLUSION
Each material showed different characteristics after etching with hydrofluoric acid. Knowledge of the proper protocol for each material is essential to ensure improvements in the adhesion process and durability of indirect restorations. In general, Celtra Duo presented mechanical properties superior to those of Lava Ultimate and Vita Enamic.
CLINICAL SIGNIFICANCE
Specific etching protocols must be recommended for each indirect material because longer exposure to hydrofluoric acid can jeopardize the surface, thus affecting the mechanical and bond strength properties.
Topics: Hydrofluoric Acid; Dental Bonding; Dental Porcelain; Materials Testing; Surface Properties; Dental Materials; Resin Cements; Ceramics; Computer-Aided Design
PubMed: 36280006
DOI: 10.1016/j.jdent.2022.104348 -
Journal of the Mechanical Behavior of... Jun 2021The study aims to quantify the viscoelastic properties of representative dental CAD/CAM resin-based composites (RBC) and to determine the effects of loading frequencies...
OBJECTIVE
The study aims to quantify the viscoelastic properties of representative dental CAD/CAM resin-based composites (RBC) and to determine the effects of loading frequencies on the viscoelastic material response in comparison to clinically established CAD/CAM glass ceramics.
METHODS
Eight RBCs, one leucite-reinforced, and one lithium disilicate glass-ceramics were selected. The quasi-static (indentation hardness H, indentation modulus, E) and viscoelastic (storage modulus E', loss modulus E″, loss factor tan δ) material behavior was monitored by a depth-sensing indentation test equipped with a DMA module. A low-magnitude oscillating force was therefore superimposed onto a quasi-static force (F = 1000 mN) at 20 different frequencies in the range 1-50 Hz. One and multiple-way analysis of variance (ANOVA), the Tukey honestly significant difference (HSD) post-hoc tests (α = 0.05), and a Pearson correlation analysis were used for data analysis.
RESULTS
The quasi-static parameters increased with the crystalline phase in glass ceramics and with the amount of inorganic filler in RBCs. The tan δ, which is related to the damping capacity of a material, increased with the increasing amount of glass phase in glass ceramics or with the amount of organic phase in RBCs. A pronounced influence of the frequency on the measured parameters and their patterns of variation was observed. H was up to ten time higher in glass ceramics compared to RBCs and highest at the lowest frequency (1 Hz). Parameters E and E' differ less and were lowest at the lowest frequency. E″ distinguished three different patterns of variation with frequency. The tan δ decreased rapidly with frequency in glass ceramics, while the decrease in RBCs was gradually. Frequency influenced stronger tan δ (p < 0.001, η = 0.85), followed by E' (p < 0.001, η = 0.773), E (p < 0.001, η = 0.772), and E″ (p < 0.001, η = 0.714), and less H (p < 0.001, η = 0.384).
CONCLUSIONS
All materials sowed viscoelastic behavior related to their microstructure and the internal friction created by grain or interphase boundary relaxation. RBCs have better damping capabilities over a wider frequency range. The deviations from the ideal elasticity were significantly lower in the glass ceramics than in the RBCs.
Topics: Ceramics; Composite Resins; Computer-Aided Design; Dental Materials; Dental Porcelain; Hardness; Materials Testing; Surface Properties
PubMed: 33657506
DOI: 10.1016/j.jmbbm.2021.104427 -
Journal of Oral Science Oct 2021To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in...
PURPOSE
To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in primary molars.
METHODS
Occluso-mesial cavities in second primary artificial molars were randomly restored using different materials (Filtek Z500 or Filtek Bulk Fill composites or high-viscosity glass ionomer cement Ketac Universal) and different matrix system (Tofflemire, AutoMatrix, matrix band with ring, contoured sectional matrix) (n = 12). Proximal contact tightness was measured using a custom-made device in an Instron 3345, and proximal surface morphology and marginal adaptation were scored after digital scanning. Two-way ANOVA, Tukey and Fischer's exact tests were performed (P < 0.05).
RESULTS
Proximal contact tightness values were significantly influenced by the restorative material (P < 0.05), the matrix system (P < 0.001), and their interaction (P < 0.01). Both resin composites showed statistically differences in proximal shape according to the matrix used to restore and exhibited overhanging margins. Ketac Universal restorations showed similar morphology and gaps on the margins regardless of the matrix system.
CONCLUSIONS
Overall, both composite restorations achieved tighter proximal contact than those restored with the high-viscosity glass ionomer cement. None of the matrix systems tested provided a convex seamless proximal morphology.
Topics: Dental Materials; Glass Ionomer Cements; Molar; Tooth, Deciduous; Viscosity
PubMed: 34511588
DOI: 10.2334/josnusd.21-0264 -
The Journal of Prosthetic Dentistry Dec 2022Studies that compared the fracture strength of monolithic lithium disilicate and 5-mol% yttria partially stabilized zirconia multiunit fixed dental prostheses are sparse.
STATEMENT OF PROBLEM
Studies that compared the fracture strength of monolithic lithium disilicate and 5-mol% yttria partially stabilized zirconia multiunit fixed dental prostheses are sparse.
PURPOSE
As the connector is the weakest part of a fixed dental prosthesis, the purpose of this in vitro study was to investigate the effect of connector designs and material on the fracture strength of 3-unit monolithic fixed dental prostheses.
MATERIAL AND METHODS
Resin-ceramic canine and premolar teeth (N=144) were prepared for fixed dental prosthesis abutments. Prostheses with 3 connector designs (width=height, width
height) were made from 2 types of lithium disilicate (IPS e.max CAD and Amber Mill) and 5-mol% yttria partially stabilized zirconia (3M Lava Esthetic and Katana Zirconia UTML). Fracture strengths were measured after 200 000 cycles of dynamic loading of 50 N and thermocycling at 5 °C and 55 °C, and the fracture patterns were analyzed. Two-way analysis of variance and the Fisher exact test were used for statistical analysis (α=.05). RESULTS
The material and connector design affected the fracture strength of fixed dental prostheses (P<.05), and a significant interaction was found between the material and connector design (P<.05). The IPS e.max CAD material had significantly lower fracture strength than Amber Mill, 3M Lava Esthetic, or Katana Zirconia UTML (P<.05). Connector designs with a greater width versus height showed significantly lower fracture strengths than other designs (P<.05).
CONCLUSIONS
The connector design of 3-unit fixed dental prostheses, particularly the connector height, may affect fracture strength depending on the prosthesis material.
Topics: Dental Stress Analysis; Dental Restoration Failure; Amber; Materials Testing; Esthetics, Dental; Dental Implants; Dental Porcelain; Zirconium; Computer-Aided Design; Ceramics; Dental Materials
PubMed: 36334990
DOI: 10.1016/j.prosdent.2022.09.018 -
The Journal of Prosthetic Dentistry Apr 2022Composite resins and glass-ceramics are both used to restore worn teeth. Which restoration material is more durable is unclear.
STATEMENT OF PROBLEM
Composite resins and glass-ceramics are both used to restore worn teeth. Which restoration material is more durable is unclear.
PURPOSE
The purpose of this in vitro study was to evaluate the load to failure of thin composite resins and glass-ceramic restorations on enamel and dentin under increasing repetitive loads.
MATERIAL AND METHODS
Glass-ceramic blocks (IPS e.max CAD; Ivoclar AG) were shaped into cylinders (Ø4.0×1.0 mm), crystallized, and adhesively luted to bovine dentin and enamel substrates that were embedded in polymethyl methacrylate (n=20). Identical direct composite resin restorations (Clearfil AP-X; Kuraray Noritake Dental Inc) were made and directly applied on the same substrates (n=20). All specimens were tested in a pneumatic device with a stainless steel ball that provided a stepwise increase of the load (N) starting at 250 N and increasing by 50 N after every 10 000 cycles to a maximum of 1150 N. Failures were detected by a displacement sensor and defined by chipping of restorative material or catastrophic failure.
RESULTS
On dentin, composite resin showed a significantly higher fatigue resistance than glass-ceramic. On enamel, no significant difference was found between the 2 materials.
CONCLUSIONS
When bonded to dentin, thin direct composite resin restorations were more durable than glass-ceramics. When bonded to enamel, no difference was found.
Topics: Animals; Cattle; Ceramics; Composite Resins; Dental Enamel; Dental Materials; Dental Porcelain; Dental Restoration Failure; Dental Stress Analysis; Dentin; Materials Testing
PubMed: 33349464
DOI: 10.1016/j.prosdent.2020.11.002 -
Journal of Dentistry May 2022To analyze the influence of the restorative material type (definitive and interim) and its surface treatment (polished or glazed) on the scanning accuracy of an...
PURPOSE
To analyze the influence of the restorative material type (definitive and interim) and its surface treatment (polished or glazed) on the scanning accuracy of an intraoral scanner.
MATERIAL AND METHODS
A mandibular dental typodont containing 3 typodont teeth (left second premolar and left first and second molars) was used for testing. Ten groups were created based on the crown material: typodont tooth (control group), gold (G group), zirconia (Z group), lithium disilicate (LD group), hybrid ceramic (HC group), composite resin (CR group), conventional PMMA (CNV-PMMA group), bis-acryl composite resin (CNV-BA group), milled PMMA (M-PMMA group), and additively manufactured bis-acryl-based polymer (AM-BA group). Except the G group, groups were subdivided into polished (P subgroups) or glazed (G subgroups). Each specimen was digitized by using an extraoral scanner (D1000; 3Shape A/G) and an intraoral scanner (TRIOS 4; 3Shape). Each reference scan was used to measure the discrepancy with the corresponding 15 intraoral scans by calculating the root mean square (RMS) error (Geomagic; 3D Systems). The Welch ANOVA and Games-Howell tests were selected to examine trueness (α=0.05). The F-test with Bonferroni correction was used to evaluate precision.
RESULTS
Significant trueness and precision differences were found (P<.001). The G-P subgroup had the lowest trueness values, while the CNV-PMMA-P, M-PMMA-P, and AM-BA-P subgroups had the highest trueness values. Significant RMS mean discrepancies were computed when comparing polished and glazed specimens fabricated with the same material (P<.001). The CNV-PMMA-G subgroup had the lowest precision values, while the CNV-BA-P subgroup had the highest precision values (P<.001).
CONCLUSIONS
The type and surface finishing of the restorative materials tested influenced the scanning accuracy of the IOS tested. The lowest trueness values were found in the high noble alloy specimens, while the highest trueness values were measured in conventional and milled PMMA and additively manufactured bis-acryl-based polymer polished specimens. Except for zirconia crowns, higher trueness values were found in polished specimens when compared with glazed crowns. The CNV-PMMA-G subgroup had the lowest precision values, while the highest precision values were measured in the CNV-BA-P subgroup.
CLINICAL SIGNIFICANCE
Definitive and interim materials tested decrease intraoral scanning accuracy. Furthermore, polishing instead of glazing definitive and interim material assessed might be preferable to maximize intraoral scanning accuracy.
Topics: Composite Resins; Computer-Aided Design; Dental Impression Technique; Dental Materials; Imaging, Three-Dimensional; Models, Dental; Polymethyl Methacrylate
PubMed: 35358659
DOI: 10.1016/j.jdent.2022.104114 -
Clinical Oral Investigations Aug 2022Investigate the effect of erosive challenge with hydrochloric acid (HCl) on the surface of five different restorative materials.
OBJECTIVE
Investigate the effect of erosive challenge with hydrochloric acid (HCl) on the surface of five different restorative materials.
MATERIAL AND METHODS
Ten plates of five restorative materials (Admira Fusion, Activa BioActive-Restorative, Charisma, Equia Forte HT Fil/EF, Filtek Universal Restorative/FU) were obtained. Half of the plate surfaces was covered with an adhesive tape, creating a control area, and the other side was submitted to the HCl (0.06 M HCl; pH 1.2; at 37 °C; for 30 h). Plates with control and HCl-treated areas were analyzed regarding the surface roughness (Sa), roughness profile (Rv), surface loss (SL), microhardness (MI), and gloss (GL) (n = 10). Surface morphology was analyzed by SEM and chemical elements were identified by EDX (n = 5). Data were evaluated by ANOVA and Tukey's test (α = 0.05).
RESULTS
Most materials were not affected by HCl. FU showed the lowest Sa and Rv, and the highest GL after HCl. On the other hand, EF presented the highest Sa, Rv, and SL, and the lowest GL. The MI of materials was not changed after HCl. Topographical and chemical alterations were observed after HCl only for EF.
CONCLUSIONS
The composites showed minor surface changes after HCl, which was not observed for the glass ionomer cement (EF). FU presented the best performance regarding the parameters evaluated.
CLINICAL RELEVANCE
The effects of erosive challenge with HCl on composites were minimal, while the glass ionomer cements might not be indicated as restorative material for patients with gastroesophageal reflux disease.
Topics: Composite Resins; Dental Materials; Glass Ionomer Cements; Humans; Hydrochloric Acid; Materials Testing; Surface Properties
PubMed: 35441897
DOI: 10.1007/s00784-022-04487-w -
Journal of Esthetic and Restorative... Sep 2021To determine color and translucency stability of present-day resin-based restorative materials.
OBJECTIVE
To determine color and translucency stability of present-day resin-based restorative materials.
MATERIALS AND METHODS
Disk-shaped (1.0 × 10 mm) resin composites (Filtek Universal, 3M ESPE; Spectra ST, Dentsply Sirona; Gradia Direct X, GC America; Estilite Quick, Tokuyama; Harmonize, Kerr; ACTIVA Bioactive-Restorative, Pulpdent) were prepared and divided into four staining groups (n = 5); coffee (55°C), grape juice (5°C), deionized water (25°C) and thermocycling (20 000 cycles, 5°C to 55°C with a 30-second dwell time). Spectrophotometer measurements were taken at baseline and 14 days for each group and the color stability (CIEDE2000) and changes in the translucency parameter (RTP ) and luminous transmittance of each composite were determined. A 2-way analysis of variance (ANOVA) using maximum likelihood estimations was used for analysis for these changes, with subsequent pairwise comparisons using Bonferroni-corrected Student's t tests and an experiment-wise α = 0.05.
RESULTS
A significant interaction (P < .0001) between material and treatment was found for each change in the esthetic property tested over 14 days. Multiple significant differences between materials for each treatment and between treatments for each material were identified.
CONCLUSIONS
The severity of color change and translucency of resin-based materials are dependent on their type, mostly affected by the coffee staining medium. Nano-filled resin composite is most resistant to color change and with stable translucency after artificial aging.
CLINICAL RELEVANCE
Nano-filled resin composite may be the most esthetically durable resin- based restorative material. Micro-hybrid resin composite and resin-modified glass ionomer restorative material are susceptible to color change and losing their translucency. Hot coffee solution may shorten the esthetic lifespan of a resin-based material.
Topics: Color; Composite Resins; Dental Materials; Humans; Materials Testing; Spectrophotometry; Surface Properties
PubMed: 32797672
DOI: 10.1111/jerd.12640