Feldspathic Ceramics Research Articles

Biomechanical Behaviors of Molars Restored with Endocrowns Composed of Different Materials.

To assess the biomechanical behaviors of endodontically treated molars (ETMs) restored with endocrowns composed of different materials, forty mandibular molars were assigned to five groups (n = 8 each). Untreated molars constituted the control group (group C); the rest of the teeth that underwent root canal therapy were restored with endocrowns composed of polycrystalline ceramics (ST zirconia®, UPCERA) in group ZR, lithium disilicate glass ceramics (UP.CAD®, UPCERA) in group LD, resin-based nanoceramics (Hyramic®, UPCERA) in group NC, and feldspathic ceramics (CEREC Blocs®, Sirona) in group FC. All teeth were axially loaded until fracture. The process was recorded using a high-speed camera system, and fractographic analysis was conducted. The results showed that fracture loads did not significantly differ among groups C, LD, and NC; the loads were significantly lower than the load in group ZR but higher than the load in group FC. The mean time from the initial crack to complete tooth fracture varied. Group C had the longest time, followed by group NC; groups ZR, LD, and FC had the shortest time. Similar failure patterns were observed in groups ZR and LD, which were more regular than the pattern in group NC; group FC exhibited the roughest fracture surfaces. Fracture resistance testing combined with a high-speed camera system and fractographic analysis provides a promising modality for studying the biomechanical behaviors of restored teeth. Endocrowns composed of lithium disilicate glass ceramics or resin-based nanoceramics offer alternative restorations for ETMs with extensive coronal loss.

Achieving a Lighter Shade: Adjusting the Color of Layered Lithium Disilicate Fixed Dental Restorations with Feldspathic Ceramic Veneers

The aim of this case report is to present an aesthetic restoration of the anterior dentition using the feldspathic ceramic veneers. The current study narrows down the analysis to a clinical case where lithium disilicate restorations had an inadequate esthetic result that involved uneven color and the clearly visible discoloration of the substrate. To solve such problems and at the same time maintain esthetics, feldspathic veneers were placed on the teeth. The outcome of the study revealed that the utilisation of feldspathic veneers offers a viable and cosmetically satisfactory solution to the issue of colour differences and surface porosity. A veneer is only successful if it is prepared properly, bonded well, and is made out of feldspathic ceramics which are inherently esthetic. This case thus provides an excellent case against some of the arguments that feldspathic veneers are very poor under heavily reduced circumstance by showcasing how these ceramics can perform well even under these circumstances. The research presented in the work increases the interest in using feldspathic ceramics in restorative dentistry and specific cases, in particular.

Case Report: Managing Complications of Feldspathic Ceramic Fractures in Zirconia-Based Crowns with Feldspathic Veneers

This case report describes the clinical approach in managing a fractured feldspathic ceramic layer in a zirconia supported restoration with a new feldspathic veneer; minimal intervention. The case involved chipping of ceramics at tooth 1.1, in which the damaged part was removed and replaced, sparing the tooth from further intensive preparations or changes to the zirconia framework. The technique involved in the procedure include hydrofluoric acid etching, silanization, and resin cementation to foster a high bond strength. The outcomes of the study revealed an excellent aesthetic result with the replanted veneer blending properly with adjacent teeth. This case raises evidence for using feldspathic ceramics in zirconia-based restorations and demonstrates that such complications can be resolved with stability of function and esthetics. The less invasive treatment modality and the short time taken to restore the teeth suggest the feldspathic veneers as potential solution for similar long-term dentition restoration.

Survival, technical and biological outcome of fixed tooth- and implant-supported restorations: A retrospective analysis of a patient cohort treated in an undergraduate dental education program

ObjectivesThere is a paucity of data on the outcome of fixed tooth- and implant-supported porcelain-fused-to-metal (PFM) and ceramic-based (CB) restorations fabricated during undergraduate dental education. Therefore, this retrospective study examined the outcome of fixed restorations placed in patients participating in an undergraduate program. MethodsPatient records were searched for data on fixed PFM and CB restorations. For these restorations, the functional period in situ and technical and biological complications, namely restoration fracture, decementation, screw loosening, secondary caries, and loss of vitality, were recorded. Periodontal parameters were also documented. Kaplan-Meier survival and complication estimates after 1 and 5 years were calculated for restoration types, materials, designs (veneered/non-veneered), cementation/retention modes and localizations with group sizes ≥ 15. Regression models were used to analyze the influence of demographic data and abovementioned restoration characteristics on restoration survival, technical and biological outcome. Results1196 restorations with a mean observation time of 5 years were included in the analysis. The different restoration types exhibited survival rates of > 90.8% after 5 years, accompanied by a favorable biological outcome. However, monolithic resin-matrix or feldspathic ceramic restorations were found to have a higher fracture rate than lithium disilicate or zirconium dioxide ceramic restorations resulting in lower survival rates for these restorations. Additionally, resin-matrix ceramic restorations showed a higher decementation rate than lithium disilicate restorations. ConclusionsFixed tooth- and implant-supported CB restorations fabricated from lithium disilicate and zirconium dioxide ceramics demonstrated better survival and lower complication rates than restorations fabricated from resin-matrix or feldspathic ceramics in an undergraduate dental education program. Clinical significanceDue to the more favorable outcome of CB restorations fabricated from lithium disilicate or zirconium dioxide ceramics, undergraduate dental education should focus on the application of these ceramics to increase restoration survival by reducing technical complications.

Evaluation of Hardness and Wear of Conventional and Transparent Zirconia Ceramics, Feldspathic Ceramic, Glaze, and Enamel.

The aim of the study was to compare the hardness, coefficient of friction, and wear experienced by four different ceramic samples: 3Y-TZP zirconium oxide ceramics-Zi-Ceramill Zi (Amman Girrbach), 5Y-PSZ transparent zirconium oxide ceramics-Zol-Ceramill Zolid (Amman Girrbach), Sak-feldspathic ceramics-Sakura Interaction (Elephant), and Glaze (Amman Girrbach). The Vickers hardness of the samples was measured. Friction tests ball-on-disc were performed between the discs of four ceramics and a zirconia ceramic ball, then a premolar tooth as a counter-sample. The mass loss and the friction coefficients of the ceramic samples were determined. The tooth counter-samples were 3D scanned, and enamel attrition depths and mass were measured. The following hardness values (HV1) were obtained: 1454 ± 46 HV1 for Zi, 1439 ± 62 HV1 for Zol, 491 ± 16 HV1 for Sak, 593 ± 16 HV1 for Glaze, and 372 ± 41 HV1 for enamel. The mass losses of the teeth in contact with ceramics were 0.1 mg for Zi, 0.1 mg for Zol, 5.5 mg for Sak, and 4 mg for Glaze. Conventional and transparent zirconium oxide ceramics are four times harder than enamel and three times harder than veneering ceramics. Zirconia ceramics exhibit lower wear and a more homogenous, smoother surface than the other ceramics. Tooth tissues are subject to greater attrition in contact with veneering ceramics than with polished zirconium oxide ceramics.

Effect of thermocycling on the mechanical properties of permanent composite-based CAD-CAM restorative materials produced by additive and subtractive manufacturing techniques

BackgroundThe aim of the study was to determine and compare the biaxial flexural strength (BFS) and Vickers hardness (VHN) of additive and subtractive manufactured permanent composite-based restorative materials, before and after thermal aging.MethodsA total of 200 specimens were prepared; 100 disc-shaped specimens (diameter 13 × 1.2 mm) for the BFS test and 100 square specimens (14 × 14 × 2 mm) for the VHN test. The specimens were made from various materials: two subtractive composite-based blocks (Cerasmart 270 [CS], Vita Enamic [VE]), two additive composite-based resins used for two different vat polymerization methods (digital light processing [DLP]; Saremco Print Crowntec [SC] and stereolithography [SLA]; Formlabs Permanent Crown Resin [FP]), and one feldspathic glass-matrix ceramic block (Vita Mark II [VM]) as the control group. Specimens of each material were divided into two subgroups: thermal cycled or non-thermal cycled (n = 10). BFS and VHN tests were performed on all groups. Data were analyzed with two-way ANOVA and post hoc Tukey test (α = 0.05).ResultsThe type of restorative material used for the specimen had a statistically significant influence on both BFS and VHN values. However, thermal cycling did not affect the BFS and VHN values. After thermal cycling, the results of the BFS test were ranked from best to worst as follows: CS, FP, SC, VE, then VM. For the VHN values, the order from best to worst was as follows: VM, VE, CS, FP, then SC.Conclusions3D printed and milled composite groups showed higher BFS than feldspathic ceramics. When the VHN results were examined, it was seen that the 3D resin groups had the lowest VHN values. Furthermore, it was observed that the thermal cycle had no effect on BFS or VHN.

Lithium disilicate ceramic veneers as an alternative for aesthetic rehabilitation in upper anterior teeth: Case report

Ceramic dental veneers are currently a solution for long-term aesthetic rehabilitation of anterior teeth. As a conservative treatment, it allows maintaining a significant amount of dental tissue and at the same time achieving an acceptable aesthetic result. The clinical case of a 39-year-old female patient, professional, with no personal or family clinical pathological history, who came to the consultation due to presenting dissatisfaction with her smile and color of the teeth in the upper anterior sector, is presented. As an alternative for aesthetic rehabilitation, he was offered the application of lithium disilicate ceramic veneers on the upper anterior teeth. The technique was performed using lithium disilicate, allowing a reliable aesthetic restoration with minimal preparation of the dental tissue structure. Ceramic veneer restorations are highly durable and safe procedures when appropriate adhesive protocols are used. Lithium disilicate, in particular, exhibits superior strength to feldspathic ceramics and possesses superior optical properties to zirconium. For this reason, it is considered an ideal material for anterior aesthetic rehabilitation using ceramic veneers. The application of lithium disilicate ceramic veneers allows successful rehabilitation by combining desirable characteristics for both the professional and the patients, including aesthetics, high resistance and ease of use

Clinical management of vital and non-vital discolored tooth preparation stump shades: A clinical case series.

Traditional and modern-day laboratory techniques can be used to mask vital and non-vital discolored teeth. Two clinical case reports are presented showing different treatment approaches to differing clinical scenarios of partial coverage veneer and full coverage crown restorations, respectively. Feldspathic ceramics should be considered when customization of stump shade correction and equalization is required with minimum facial reduction with veneer restorations. Translucent zirconia (5 mol% Y2 O3 ) can be used to mask metal posts and core restorations on non-vital teeth using an opaquer material that is infused into the intaglio surface in the green state. Different clinical scenarios will present to the clinician in regard to discolored stump shades where understanding what laboratory material treatment options are available that will help guide definitive restoration types and ultimately tooth preparation design.

Clinical Applications and Mechanical Properties of CAD-CAM Materials in Restorative and Prosthetic Dentistry: A Systematic Review.

Clinical outcomes of dental restorations depend primarily on the choice of materials used, and nowadays, dental CAD-CAM (Computer-Aided Design Computer-Aided Manufacturing) materials have strongly changed daily clinical practice. The aim of this systematic review is to analyze CAD-CAM dental materials according to their mechanical properties and in relation to their clinical applications. A literature review was performed on PubMed, Scopus, Web of Knowledge, and the Cochrane Library. Articles addressing at least one of the following topics regarding dental materials for CAD-CAM systems: manufacturers, mechanical features, materials' composition, optical properties, clinical indications, and/or outcomes were included in the review. A flowchart was performed as described in the PRISMA guidelines. Among the 564 articles found, 63 were analyzed and evaluated. Within the limitations of this systematic review, it can be concluded that CAD-CAM materials present a wide range of clinical applications due to their improved mechanical properties. Specifically, in addition to materials that have been in use for a long time (such as feldspathic ceramics), resin block composites can also be used for permanent restorations.

Masking ability of CAD/CAM monolithic ceramics: effect of ceramic type and thickness, and try-in paste shade.

This in vitro study evaluated the color differences when discolored tooth substrates were restored with CAD/CAM monolithic ceramics depending on ceramic type and thickness, and the try-in paste shade. Six ceramic types were tested: high-translucent lithium disilicate (LD-HT); medium-translucent lithium disilicate (LD-MT); low-translucent lithium disilicate (LD-LT); low-translucent leucite (LC-LT); feldspathic ceramic (FC); and BL1 low-translucent lithium disilicate, stained to A1 shade (LD-BL1-LT). The ceramics were tested in disk-shaped specimens with 0.5-, 1.0-, and 1.5-mm thickness (n = 10; N = 180; shade A1). The try-in pastes were tested to simulate luting materials and corresponded to colors A1 and Opaque White. Six substrates were used: A1 (reference), B2, B3, A3, C2, and C3. Color differences (∆E00) and translucency parameter (TP00) were assessed with the CIEDE2000 formula. The results were compared with acceptability (1.77) and perceptibility (0.81) thresholds. Ceramic type, thickness, and the try-in paste shade influenced the color differences. LD-LT and LC-LT ceramics and Opaque White try-in paste provided, in general, lower ∆E00 values. The most adequate ceramic thickness varied according to the substrate discoloration. With 1.0 mm of ceramic thickness, it was possible to obtain ∆E00 lower than the perceptibility threshold for substrates C2 and A3, and ∆E00 lower than the acceptability threshold for C3 and B3. ∆E00 lower than the acceptability threshold were obtained with 0.5 mm of ceramic thickness for B2, A3, and C2. The use of low-translucent glass-ceramics and Opaque White try-in paste are useful to reduce color differences. The most adequate ceramic thickness depends on the substrate discoloration.

Effect of staining layer on roughness after progressive wear of monolithic ceramics.

The aim of this study was to evaluate staining layer behavior applied to high-translucency zirconia (YZHT), feldspathic ceramics (FD), and zirconia-reinforced lithium silicate (ZLS) surfaces against different antagonists. Monolithic ceramic discs (n = 120) (ø 12 mm; thickness, 1.2 mm; ISO 6872) were obtained, 30 from YZHT and FD, and 60 from ZLS CAD/CAM blocks (staining layer applied before or after the crystallization procedure). The specimens were divided into 12 subgroups (n = 10) according to the antagonists: steatite, polymer-infiltrated ceramic, or zirconia. Mechanical cycling (1.5 × 104 cycles; 15 N; horizontal displacement, 6 mm; 1.7 Hz) and flexural strength tests (1 mm/min-1000 kg cell) were performed. The differences between final and initial roughnesses (Ra, Rz, and Rsm), the mass loss, and the flexural strength data were individually analyzed by two-way ANOVA and Tukey's test (α = 0.05). The roughnesses of all ceramics did not present a statistically significant difference before wear simulation: Ra (p = 0.3348), Rz (p = 0.5590), and Rsm (p = 0.5330). After the wear simulation, the Ra parameter was not affected by an interaction between ceramic and antagonist (p = 0.595). The Rz and Rsm parameters were affected only by the antagonist pistons (both, p = 0.000). The ceramics used in this study showed statistically significant differences in mass loss after the wear test (p < 0.0001). The additional firing (2 steps) of the ZLS2 led to a higher lost mass quantity. All ceramics presented similar initial roughnesses and similar roughnesses after the wear simulation. The zirconia antagonist showed better performance against ceramics with high crystalline content. It is clear that restorative materials must be carefully selected by dental practitioners according to indications, properties, and antagonists. The steatite antagonist, that is, an enamel analog, showed better performance against vitreous ceramics, while the zirconia antagonist showed better performance against ceramics with high crystalline content. Wear affects the surface roughnesses of the ceramics. Additional firing for the staining of the zirconia-reinforced lithium silicate ceramic led to a greater loss of mass.

Comparison and Effect of Common Beverages on Color Stability of Different Esthetic Restorative Materials: An In Vitro Study.

The aim of this in vitro study is to assess the color stability of different esthetic veneer restorative materials (feldspathic ceramic, hybrid ceramic, zirconia-reinforced lithium silicate glass ceramic, and composite resin) after being exposed to commonly consumed beverages that have staining potential. Sixty specimens were prepared into rectangular blocks with fixed dimensions of 10 × 12 × 2.5 mm. Machinable feldspathic ceramic (FC), zirconia-reinforced lithium silicate glass ceramic (LS), and a hybrid ceramic (HC) were milled using CAD/CAM (n = 15), and specimens of microparticle composite resin (MPC) were manually prepared by with the same dimensions (n = 15). All specimens were randomly divided into three subgroups (= 5) according to immersing solutions used (coffee, black tea, and red wine). All specimens were immersed for a period of 72 hours. A colorimetric evaluation was done for each specimen before and after immersion using a spectrophotometer and the difference in color was calculated according to the CIE-Lab system. To analyze the data, two-way ANOVA and one-way ANOVA tests of significance were used to compare between the different study groups, followed by pairwise comparisons using post hoc test (Tukey). Different restorative materials showed statistical significance regarding color change after staining (p < 0.001); however, no statistical significance in color change (p > 0.05) was found between the different beverages used. All tested ceramic materials had better color stability compared with composite resin. All the staining beverages used in the current study might cause a significant color change in the tested restorative materials. The color stability of esthetic restorative materials affects their clinical performance in the oral cavity, where the restorative materials are usually exposed to staining beverages that are frequently consumed by patients. Therefore, it is important to understand the staining effect of the different beverages on esthetic restorative materials.

Color Assessment of Feldspathic Ceramic with Two Different Thicknesses, Using Multiple Polymeric Cements.

The purpose of this study was to evaluate the color changes of feldspathic ceramics CEREC Blocs (Dentsply Sirona, Milford, DE, USA) when cemented with different luting agents, while varying the ceramic thickness. Seventy ceramic discs of feldspathic ceramic (A2 shade) were obtained with 0.5 and 0.8 mm thicknesses. Seventy composite discs (A3 shade) 1 mm in thickness were used as substrates. After being polished and conditioned, the ceramic and composite discs were cemented with different resin cements and a flowable composite: Variolink® Esthetic Light, Neutral and Warm (Ivoclar Vivadent, Schaan, Liechtenstein); RelyXTM Veneer B0.5, Translucent and A3 Opaque/yellow shades (3M Oral Care, St. Paul, MN, USA); G-aenial® Universal Flow A2 (GC Europe, Leuven, Belgium). Color difference (ΔE) was determined using a spectrophotometer. A two-way ANOVA and multiple comparisons were performed using the Bonferroni method with a 95% confidence interval. Variolink® Neutral showed the highest ΔE (15.12 ± 0.71) and RelyXTM Veneer A3 the lowest value (1.59 ± 0.33). There are no statistically significant differences between the two ceramic thicknesses for Variolink® Light (p = 0.230) and RelyXTM Veneer B0.5 (p = 0.318) cements. The feldspathic ceramic final color is influenced by the cement used and the ceramic thickness. The use of different cements in a thin ceramic has a clinically significant impact on the final esthetic result.

Implant–Prosthetic Rehabilitation of Maxillary Lateral Incisor Agenesis with Narrow Diameter Implants and Metal–Ceramic vs. All-Ceramic Single Crowns: A 16-Year Prospective Clinical Study

The main objectives of the present prospective clinical study were to evaluate the marginal bone resorption and the peri-implant soft tissue conditions around narrow diameter implants, as well as the clinical performances of metal–ceramic and all-ceramic single crowns in the implant–prosthetic treatment of maxillary lateral incisors agenesis. Seventy-two patients affected by monolateral or bilateral agenesis of the maxillary lateral incisors were included in the study, and a total of 105 narrow diameter implants were inserted. The final single crowns were fabricated 4 months after the surgical procedures by means of either titanium abutments with Auro-Galvan Crowns (AGC) veneered with feldspathic ceramics or zirconia abutments with all-ceramic (alumina or zirconia) crowns layered with dedicated veneering ceramics. Both marginal bone resorption and soft tissue quality were evaluated after a maximum period of 16 years. Two independent survival curves for patients wearing AGC or all-ceramic crowns were calculated by means of Kaplan–Meier analysis, and a log-rank test was performed in order to compare these curves (p &lt; 0.05). After 16 years of clinical function, a mean marginal bone resorption of 1.2 ± 0.61 mm and good response of peri-implant soft tissues were observed. Descriptive statistics resulted in 80% and 87.1% cumulative success rates for patients provided with AGC prostheses onto titanium abutments and all-ceramic crowns on-to zirconia abutments, respectively. The cumulative survival rate calculated for AGC group was 93.3%, whereas all-ceramic group showed a cumulative survival rate of 95.7%. No statistically significant differences were found with the log-rank tests. The overall success and survival rates calculated were 85% and 95% for all the restorations, respectively. Mucositis, abutment unscrewing, loss of retention, chipping, core fracture, and esthetic failure were the major complications reported. The implant–prosthetic approach can be considered an effective and viable solution to treat cases of maxillary lateral incisor agenesis in the long term.

Nature-mimicking layering with composite resins through a bio-inspired analysis: 25 years of the polychromatic technique.

For decades, the dental community has discussed which materials would be the ideal substitutes for lost tooth structure. Initially, the biomimetic approach advocated that feldspathic ceramics would be the material of choice for enamel. However, given the complexity of obtaining excellent dental technicians and the financial cost, are composite resins a suitable replacement? The optical properties with opalescence and fluorescence effects, as well as this material's high fracture toughness, indicate it as a long-lasting restorative material. However, because this material depends on the operator's expertise, knowledge of layering techniques and the selection of each material for the different layers is required. Thus, knowledge of the polychromatic technique through a bioinspired approach is necessary to obtain results of life-like restorations. This article aims to review the polychromatic layering technique (PLT), considering the optical and mechanical properties of dentin and enamel and correlating these properties with current composite resins to guide clinicians in selecting the most suitable restoratives for their clinical challenges. The polychromatic layering technique is revisited, cross-referencing the properties of dentin and enamel with current composite resin restoratives and their biomimetic properties. The effectiveness and predictability of the PLT are corroborated in clinical cases of varying degrees of difficulty requiring different layering strategies. After the bio-inspired analysis, using nature as a model to be understood and followed, it is possible to note how the polychromatic technique remains current and viable in mimicking nature, providing esthetic and natural results in the layering of composite resins. Composite resins effectively replicate the optical and mechanical characteristics of natural dentin and enamel through the bioinspired approach presented by the polychromatic layering technique.

Effect of Different Surface Finishing Procedures on Color Stability of Leucite-reinforced Feldspathic CAD-CAM Ceramic

Statement of the problem: The color stability of newly introduced leucite- reinforced feldspathic CAD-CAM ceramic with different surface treatments remains unclear. Objective: This in-vitro study aimed to examine the effect of different surface finishing procedures on the color stability of leucite-reinforced feldspathic CAD-CAM ceramic. Materials &amp; Methods: Twenty-four monochromatic, leucite-reinforced, A2-shaded feldspathic ceramic specimens prepared in 1 mm thickness. The specimens were randomly divided into 3 groups according to their surface finishing methods (n=8): a control group without surface finishing (Group C), surface finishing with polishing discs (Sof-Lex, 3M ESPE), and surface finishing with glaze (Group G). All the specimens were immersed in a coffee solution and kept in an incubator at 37 °C for 14 days. Initial color measurements were made with a digital spectrophotometer and the Commission Internationale de l'Eclairage (CIE) L*a*b* values were recorded. The color measurements were repeated at the ends of the 1st, 3rd, 7th, and 14th days with the spectrophotometer under the same conditions. The color change of the specimens was calculated with the CIEDE2000 (ΔE00) formula. Statistical analysis of the data was performed with a two-way mixed ANOVA and Bonferroni post-hoc tests (α=0.05). Results: Time and surface finishing procedures caused statistically significant color changes in the specimens (P&lt;0.05). However, the interaction of time and surface finishing was not statistically significant (P&gt;0.05). The lowest mean ΔE00 value was observed in Group G on day 14 (0.93 ± 0.74); the highest mean ΔE00 value was found in Group P on the 3rd and 14th days (2.16 ± 0.72). While the C and G groups exhibited similar color change values, Group P caused higher ΔE00 values compared to the glaze application (P&lt;0.05). Conclusions: Based on the findings of this study, glaze application led to less color change compared with disk polishing. Glazing can be preferred to polishing to ensure long-term color stability in leucite-reinforced feldspathic ceramics.

Effect of CAD/CAM aesthetic material thickness and translucency on the polymerisation of light- and dual-cured resin cements.

This study investigated potential variations in polymerisation of light- and dual-cured (LC and DC) resin cements photoactivated through four CAD/CAM restorative materials as a function of substrate thickness. Four CAD/CAM materials [two resin composites CeraSmart (CS) and Grandio Blocs (GB); a polymer infiltrated ceramic Vita Enamic (VE) and a feldspathic ceramic Vita Mark II (VM)], with five thicknesses (0.5, 1, 1.5, 2, and 2.5mm) were prepared and their optical characteristics measured. 1mm discs of LC and DC resin cement (Variolink® Esthetic, Ivoclar AG) were photoactivated through each specimen thickness. After 1h post-cure, polymerisation efficiency was determined by degree of conversion (DC%) and Martens hardness (HM). Interactions between materials, thicknesses and properties were analysed by linear regressions, two-way ANOVA and one-way ANOVA followed by post hoc multiple comparisons (α=0.05). All substrates of 0.5- and 1.0-mm thickness transmitted sufficiently high peak irradiances at around 455nm: (It = 588-819mW/cm2) with translucency parameter TP =21.14 - 10.7; ranked: CS>GB =VM>VE. However, increasing the substrate thickness (1.5-2.5mm) reduced energy delivery to the luting cements (4 - 2.8J/cm2). Consequently, as their thicknesses increased beyond 1.5mm, HM of the cement discs differed significantly between the substrates. But there were only slight reduction of DC% in LC cements and DC cement discs were not affected. Photoactivating light-cured Ivocerin™ containing cement through feldspathic ceramics and polymer-infiltrated ceramics achieved greater early hardness results than dual-cured type, irrespective of substrate thickness (0.5 - 2.5mm). However, only 0.5 and 1mm-thick resin composites showed similar outcome (LC>DC). Therefore, for cases requiring early hardness development, appropriate cement selection for each substrate material is recommended.

Editorial: Dental Ceramics: From Science and Technology to Clinical Application

Editorial: Dental Ceramics: From Science and Technology to Clinical Application

Solubility of Dental Ceramics in Electric Fields

Combining dental ceramics with other prosthetic metallic restorations might release metal ions, thus affecting the oral tissues of the patients. In this study, we evaluated the electrochemical solubility of various dental ceramics in a galvanic experimental setup in vitro. Smooth and rough feldspathic and zirconium dioxide ceramics (at pH 5.5 and pH 3.0) were exposed to an electric field. Calcium, barium, and zirconium were selected as parameters to determine the solubility of both types of ceramic materials. Among all test groups, feldspathic ceramics were more soluble than zirconium dioxide ceramics at low pH. The results indicated that the solubility of zirconium dioxide was not significantly affected by the presence of an electric field, although the solubility was higher when the pH was relatively lower. The feldspathic material had a higher sensitivity to acids and electrogalvanic processes. We found that the galvanic process increases the solubility of feldspathic ceramics. The surface quality is important in an acidic medium, especially for feldspathic ceramics. Zirconium dioxide ceramics are more resistant to an acidic medium and exposure to a clinically relevant electric field.

Do you know your ceramics? Part 2: feldspathic ceramics.

This is the second part of a five-part series exploring the main ceramic materials used for the fabrication of all-ceramic restorations to aid clinicians in their selection. Feldspathic ceramics have been a desirable choice for over 200 years due to their favourable optical properties. However, the physical properties of the material have been its downfall, rendering it unsuitable in posterior regions. By going into further depth of feldspathic ceramic properties, clinicians will be able to gain a better understanding of their indications as they still have a place within modern dentistry.