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This article reports a case of maxillary rehabilitation with implant-supported fixed dental prostheses on six zirconia implants. A woman with impacted maxillary canines attended our dental clinic seeking a metal-free maxillary restoration. After the extraction of both impacted maxillary canines and the placement of autogenous bone graft, six two-piece zirconia implants with straight abutments were placed in the anterior maxilla. Two zirconia fixed dental prostheses with porcelain veneering, separated at the midline, were placed on these zirconia implants. The 10-year follow-up monitored the adequate evolution of both implants and restorations with no signs of peri-implant disease. [ABSTRACT FROM AUTHOR]

Purpose: To compare the load-to-failure values of different ceramic CAD/CAM implant crown materials with drilled screw-access holes with and without cyclic loading applied. Materials and Methods: Forty zirconia abutments with a titanium base were pre-loaded onto implants to support maxillary right first premolar crowns milled from four different CAD/CAM ceramic materials (zirconia-reinforced lithium silicate, hybrid ceramic, lithium disilicate, and zirconia; n = 10 each). After cementing the crowns, the screw-access channels were prepared by drilling through the occlusal surfaces. Half of the specimens were subjected to cyclic loading for 5 million cycles at 2 Hz (n = 5/material). After cyclic loading, vertical loads were applied until failure. The load-to-failure values of all crowns were recorded and statistically analyzed. Two-way ANOVA was used with restricted maximum likelihood estimation and Tukey-Kramer adjustments (α = .05). Results: During cyclic loading, the zirconia abutment under one lithium disilicate specimen cracked at 2 million cycles, and a zirconia-reinforced lithium silicate crown also fractured. Results for the load-to-failure test series showed statistical differences between the materials. Zirconia resulted in significantly higher failure loads when compared to the other materials (P < .001). Cyclic loading did not significantly affect the load-to-failure values. Conclusion: Cyclic loading did not significantly influence the load to failure of any of the materials tested. Zirconia crowns with drilled screw access channels cemented on zirconia abutments with a titanium base had higher load-to-failure values compared to the other ceramic crown materials. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the minimum ceramic thickness needed to increase the lightness by one value by means of glass-ceramic restorations, as perceived by dental technicians, dentists, and laypersons. Materials and Methods: A total of 15 assessment pairs (= reference and test sample) were formed using glass-ceramic blocks in four different colors. Each assessment pair was comprised of two underground blocks differing by one value of lightness. On top of the underground blocks, glass-ceramic platelets were cemented in 5 different thicknesses (0.1 to 0.5 mm) in the same color as the reference. Dental technicians, dentists, and laypersons (n = 41/group) were asked to determine the presence of a color difference between the two samples under standardized light conditions. The threshold ceramic thickness was defined as the thickness at which = 50% of the evaluators were not able to perceive a difference within an assessment pair. The thresholds were analyzed, and groups were compared by applying chi-square test (P < .05). Results: The majority of dentists and dental technicians (> 50%) detected a lightness difference between test and reference samples up to a ceramic thickness of 0.5 mm. The majority of laypersons (= 50%) did not perceive lightness differences with ceramic thicknesses of 0.5 mm. If separated by the different color changes, the threshold ceramic thickness started at 0.4 mm and varied within the groups of evaluators and the lightness of the assessed color. Conclusions: A considerable number of evaluators perceived a lightness difference when minimally invasive ceramic restorations of 0.5-mm thickness were applied. The threshold ceramic thickness, however, was reduced when the lightness of the substrate was lower. [ABSTRACT FROM AUTHOR]

Purpose: To compare wear behavior, durability during in vitro mastication simulation, and fracture force of an established and a novel lithium disilicate CAD/CAM material, as well as to examine the impact of cementation and reduced ceramic thickness on durability and fracture force. Materials and Methods: Specimens (n = 8 per group) were prepared from lithium disilicate (LS2; IPS e.max, Ivoclar Vivadent) and advanced lithium disilicate (ALD; Cerec Tessera, Dentsply Sirona). Specimens were polished, and two-body wear test and thermocycling were performed (50 N, 120,000 cycles, 1.6 Hz, H2O dist., 5°C/55°C, 600 cycles). Maximum vertical loss, surface roughness, surface roughness depth, and antagonist wear were determined. Single crowns (n = 8 per group; thickness 1.5 mm/1.0 mm) were manufactured from LS2 and ALD and mounted on human molar teeth with adhesive resin (AB; CalibraCeram, Dentsply Sirona), glass-ionomer cement (GIC; Ketac Cem, 3M ESPE), and hybrid glass-ionomer cement (HGIC; Calibra Bio, Dentsply Sirona). Thermocycling and mechanical loading (2 x 3000 x 5°C/55°C, 2 minutes, H20 dist., 1.2 x 106 50 N) were performed. Fracture force was determined by a universal testing machine (1446, ZwickRoell), and one-way analysis and Bonferroni post hoc test (α = .05) were used for statistical analyses. Results: Mean (ALD: 210 ± 42.4 µm; LS2: 264.3 ± 56.1 µm) and maximum (ALD: 391.1 ± 86.3 µm; LS2: 518.3 ± 113.2 µm) wear between groups were significantly different (P ≤ .047). Fracture force varied between 1,911.4 ± 468.4 N (ALD/AB 1 mm) and 2,995.3 ± 880.6 N (LS2/GIC), without significant differences (P ≥ .152). Conclusion: ALD showed better wear behavior than LS2, but provided similar fracture force. Cementation and reduction of ceramic thickness had only minor effects on fracture force. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the effects of two different home bleaching agents on color stability and surface roughness of hybrid ceramics. Materials and Methods: Three dental hybrid ceramics (Lava Ultimate, Cerasmart, and Vita Enamic) and two different home bleaching agents (9.5% hydrogen peroxide and 22% carbamide peroxide) were used. Thirty specimens of each material were prepared with dimensions of 12 × 14 × 1 mm. Technical polishing kits were applied to one surface of the specimens for the surface finishing procedure. Color parameters (L*a*b*) of the specimens were measured. Three subgroups were determined: control (C), hydrogen peroxide (HP), and carbamide peroxide (CP) (n = 10 each). After the bleaching procedures, color parameters were remeasured and color differences (ΔE) were calculated. Surface roughness values of the specimens were detected with a profilometer. Surface analysis of one specimen of each group was performed with a scanning electron microscope. Data were analyzed by two-way ANOVA and Tukey honest significant difference tests. Results: There was an interaction between material and bleaching agent type (P < .05). The highest ΔE values were observed in CP groups, and the lowest ΔE values were observed in control groups. For surface roughness, there was not an interaction between material and bleaching agent type (P >.05). Material and bleaching agent factors had a significant effect on surface roughness (P < .05). The highest surface roughness values were detected in HP groups. Conclusion: Home bleaching agents caused clinically acceptable color differences on hybrid ceramic materials. Hydrogen peroxide increased the surface roughness of hybrid ceramics. [ABSTRACT FROM AUTHOR]

Purpose: To compare the clinical outcomes of single implants with titanium (Ti) or zirconia (Zr) abutments after up to 5 years in function.Materials and Methods: This study was a retrospective analysis on single implants with screw-retained abutments (Zr or Ti) covered with porcelain veneer placed between 2011 and 2013 at one referral specialist clinic. Clinical data from patient records were collected from 132 patients and 174 implants. Technical complications such as fractures, chipping, and abutment screw loosening were registered. Radiographs were analyzed comparing both annual bone loss and accumulated bone loss at 5 years. In 57 patients with 85 implants, the values of accumulated bone loss at 5 years were compared to baseline.Results: Technical complications occurred in 16 (9%) of the implants, most often during the first year. The following complications were found: fracture of the abutment (n = 1); loosening of the abutment screws (n = 5); and chipping of the porcelain veneer (n = 11). Ti abutments had more complications than Zr abutments (79%). Of all the implants, 45% had an annual bone loss ranging between 0.05 and 2.15 mm, and 59% had an accumulated bone loss at 5 years ranging between 0.05 and 4.25 mm. Zr abutments had a statistically significantly higher amount of yearly and accumulated bone loss at 5 years.Conclusion: Abutment material affected marginal bone loss. The Zr group displayed statistically more bone loss both yearly and after 5 years compared to the Ti group. Technical complications were not affected by abutment material but were affected by age of the patient. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the precementation mean marginal gap, fracture resistance, and mode of failure of monolithic zirconia endocrowns cemented to endodontically treated molar teeth with butt joint porcelain margins and added ferrule preparation designs.Materials and Methods: A total of 20 mandibular molars were endodontically treated and prepared to receive endocrown restorations. The teeth were randomly divided into two groups: Group B had a butt joint porcelain margin, while Group F received additional axial reduction with a shoulder finish line that added ferrule. Monolithic zirconia endocrowns were milled, and the marginal gaps were measured at four locations prior to cementation with resin cement. All samples were subjected to thermocycling, followed by compressive static loading. The maximum load causing fracture and mode of failure were recorded.Results: The mean load to failure for Group B (5,616 ± 1,503 N) was not significantly different compared to Group F (5,762 ± 1,618 N) (P = .84). Both groups recorded high rates of irreparable fractures (P = .2699, df = 2). The mean marginal gap in Group B (48.20 ± 12.37 μm) was not statistically significantly different compared to Group F (45.14 ± 8.45 μm) (P = .527).Conclusion: The addition of ferrule to the preparation design had no significant effect on the precementation mean marginal gap, fracture resistance, or mode of failure of monolithic zirconia endocrowns cemented to endodontically treated molar teeth. Monolithic zirconia endocrowns failed predominantly in an irreparable manner, but these failures were at high failure loads. The precementation mean marginal gap for both groups was small in comparison to other materials. [ABSTRACT FROM AUTHOR]

Purpose: To digitally evaluate the volumetric wear of four different implant-crown materials and their antagonists after artificial aging using an intraoral scanner (IOS) device and a laboratory desktop scanner.Materials and Methods: A total of 48 implants were restored with monolithic crowns divided according to restorative material: lithium disilicate (LDS), zirconia (ZR), polymerinfiltrated ceramic network (PICN), and porcelain fused to metal (PFM). Each specimen was scanned using a desktop scanner (LAB; iScan D104, IMETRIC 3D) and an IOS (TRIOS 3, 3Shape) before and after chewing simulation (1,200,000 cycles, 49 N, steatite antagonist, 5°C to 50°C). The obtained STL files were superimposed, and the volumetric loss of substance of the crowns and their antagonists was quantified (Materialise 3-matic). Kruskal-Wallis, Spearman rho, and paired t tests were used to analyze the data (α = .05).Results: The means of volume loss for each restorative material varied between 0.05 ± 0.06 mm3 (ZR with IOS) and 3.42 ± 1.65 mm3 (LDS with LAB). The wear of the antagonists was significantly lower (P < .05) for ZR than the other groups. Increased wear of the crowns was highly correlated with increased wear of their antagonists (rs = 0.859). When comparing the wear measurement using the two scanning devices, no difference in mean volume loss was found (IOS: 1.81 ± 1.81 mm3; LAB: 1.82 ± 1.78 mm3) (P = .596).Conclusion: Polished ZR was the most wear-resistant material and the least abrasive to the respective antagonist among the tested ceramics. For the quantification of wear, this IOS device can be used as an alternative to desktop scanners. [ABSTRACT FROM AUTHOR]

Purpose: To perform application of universal bonding agent based only on the manufacturer's instructions for CAD/CAM-manufactured feldspathic and hybrid ceramics and to investigate the bond strength of the composite resin to these ceramics.Materials and Methods: A total of 120 samples (2-mm thickness) were obtained from three different CAD/CAM-manufactured ceramics each: a feldspathic ceramic (Vitablocs Mark II), a hybrid ceramic (Cerasmart, GC), and a dual-network ceramic (Vita Enamic). Each of these restorative materials was divided into six subgroups (n = 20 each) in order to apply universal adhesives: All-Bond Universal, Clearfil Quick Universal, Premio Bond, Optibond XTR, Prime&Bond, and Tokuyama Universal Bond. Each bonding agent was applied according to the manufacturer's instructions. Microshear bond strength test was performed at a crosshead speed of 1 mm/min. Two-way analysis of variance (ANOVA) and Tukey post hoc tests were used for statistical analyses.Results: The data suggested a significant impact of bonding agent on all restorative materials applied (P < .001); however, only Prime&Bond demonstrated different effects between materials, with a significant difference between Vitablocs Mark II and Cerasmart restorative materials (P = .001).Conclusion: All universal bonding agents provided an acceptable bond strength for each ceramic. Since different universal bonding agents affected the bond strength between ceramics and composite resin, selecting the most suitable bonding agent for each material will increase the bond strength and clinical success. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the marginal fit of zirconia (Zi) CAD/CAM crowns in terms of gap and overhang compared to lithium disilicate (LDS) computer-aided design crowns, as well as the effect of finish line design on marginal accuracy.Materials and Methods: Stone dies were acquired from two master metal dies (n = 20 each) with two different finish lines and were scanned to produce digital models. Ceramic crowns (ZS-Ronde Zi, KaVo and IPS e.max CAD LDS, Ivoclar Vivadent) were designed and milled on the resulting 40 dies: 10 Zi-shoulder, 10 Zi-chamfer, 10 LDSshoulder, and 10 LDS-chamfer. Marginal gap and overhang were evaluated at six designated margin locations. The data were obtained, and the influence of material and finish line on the marginal fit of crowns was assessed using two-way analysis of variance and Bonferroni multiple comparisons test (α = .05).Results: Mean marginal gap and overhang on Zi crowns were 30 ± 14 μm and 79 ± 27 μm for the shoulder, respectively, and were 68 ± 34 μm and 104 ± 34 μm for the chamfer. The corresponding values for LDS crowns were 57 ± 22 μm and 74 ± 29 μm for the shoulder, and 62 ± 12 μm and 59 ± 27 μm for the chamfer. ANOVA revealed that the differences in marginal gap between the two materials were not significant (P > .05), but that the finish line effect and interaction were significant (P < .05). With regard to marginal overhang, significant differences were found between Zi and LDS crowns (P < .05), although the finish line geometries did not show any significant differences (P > .05). LDS crowns showed no differences between shoulder and chamfer margins for gap or overhang (P > .05), whereas significant differences were found in marginal gap between the Zi shoulder and chamfer margins (P lt; .005).Conclusion: In terms of marginal accuracy, shoulder margins produced smaller marginal gaps compared to chamfers for Zi CAD/CAM crowns. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the success of monolithic endocrowns fabricated using a digital workflow.Materials and Methods: Twenty-three patients requiring restoration of devitalized molars or premolars were included in the study. The preparation was scanned using an intraoral scanner (Cerec Bluecam, Dentsply Sirona), and a monolithic restoration was made from a nanoparticle resin-based hybrid composite (#10 Cerasmart [CS]; #10 Lava Ultimate [LU], 3M Espe) or a polymer-infiltrated ceramic (#10 Vita Enamic [VE]). At the time of placement and after 6 months, 1 year, and 5 years of function, radiographs were taken to evaluate the marginal integrity of the restorations, and clinical pictures were taken to assess the quality of the restoration using the USPHS criteria.Results: After 5 years, the restorative success rate was 70.8%, the restorative survival rate was 87.5%, and the tooth survival was 91.6%. Four chippings (two LU, two CS), three fractures (three LU), and two debonding of the restorations (two CS) occurred. Also, two teeth were extracted after 5 years of follow-up (two VE) because of secondary caries and a root fracture. The USPHS ratings were high, except for color match, which was rated the lowest at all time intervals.Conclusion: Nanoceramic endocrowns made using a completely digital workflow have an acceptable survival rate after 5 years. However, the complication rate was high. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this exploratory in vitro study was to compare and evaluate the load-bearing capacity (LBC) of ceramic-veneered zirconia and composite-veneered polyetheretherketone (PEEK) three-unit fixed dental prostheses (FDPs) with and without thermocycling (TC).Materials and Methods: The study included 40 samples of three-unit FDPs replacing mandibular first molars. The four groups included were: ceZIR (feldspathic ceramic-layered zirconia), ceZIR TC (feldspathic ceramic-layered thermocycled zirconia), cPEEK (composite-layered PEEK), and cPEEK TC (composite-layered thermocycled PEEK) (n = 10 per group). All frameworks were CAD/CAM milled. Ten PEEK and 10 zirconia samples were subjected to TC (6,000 cycles). All 40 FDP specimens were loaded by applying static load, using a universal testing machine. The maximum load required to fracture the specimens denoted the LBC. The comparison of LBC between the four groups was done by using two-way ANOVA with Tukey's post-hoc analysis (α = .05).Results: There was no statistically significant difference between LBC of cPEEK and ceZIR (P > .001) without thermal aging. LBC values decreased considerably for thermally aged specimens. Statistically significant differences were observed between LBC of cPEEK TC and ceZIR TC (P < .001), cPEEK TC and cPEEK (P < .001), and ceZIR TC and ceZIR (P = .001). On fracture analysis, cPEEK showed delamination failures whereas ceZIR displayed catastrophic connector fractures.Conclusion: This comparative evaluation offers preliminary data highlighting substantial depreciation in the LBC of layered PEEK under simulated intraoral conditions, thus raising a question regarding the clinical longevity of layered PEEK multi-unit restorations. In contrast, feldspathic-layered zirconia can be suitable for use in posterior FDPs. [ABSTRACT FROM AUTHOR]

Purpose: To assess the shear bond strength of composite resin to poly(etheretherketone) (PEEK) after mechanical and chemical surface treatments. Materials and Methods: A total of 48 PEEK discs were fabricated and divided equally into four surface treatment groups (n = 12 each): (1) airborne-particle abrasion (APA) with 50-µm alumina particles at 2-MPa pressure for 10 seconds; (2) 98% sulfuric acid etching for 1 minute; (3) APA + sulfuric acid etching; and (4) no surface treatment. Specimens were conditioned, and then veneering composite resin was applied to the PEEK surfaces and polymerized. Bond strength was measured using a universal testing machine. One-way analysis of variance and Tukey post hoc test were applied for statistical analysis. Results: The mean shear bond strength values of the sulfuric acid etching group were higher than that of the APA + acid etching, APA, and control groups (P < .05). Mean shear bond strength values for the APA + acid etching samples were higher than for the control and APA groups (P < .05). Conclusion: There was no significant difference between the samples treated with APA and the control group. The bond strength was highest when PEEK was prepared with sulfuric acid etching alone. [ABSTRACT FROM AUTHOR]

In recent years, numerous new dental materials have been introduced as alternatives to metal-ceramics for restorations on teeth and implants. This position paper presents the current evidence and respective clinical recommendations of the European Association for Osseointegration (EAO), one of the scientific partners of the International Journal of Prosthodontics, on material selection for single crowns (SCs) and multiple-unit implant-supported fixed dental prostheses (FDPs). Metal-ceramic restorations can be utilized in most clinical indications and are preferred to ceramic restorations in incidences such as long clinical implant crowns; cantilever implant restorations where one implant is supporting two crowns; implant-supported FDPs with extension units extending more than 7 to 8 mm (premolar size); implant-supported FDPs with more than two pontics; and implant-supported FDPs with small connector diameters due to limited intraocclusal space. Veneered or monolithic zirconia-ceramic and veneered or monolithic reinforced glass-ceramic implantsupported SCs are indicated for most SC cases in both the anterior and posterior areas. Today, implantsupported zirconia-ceramic FDPs that are conventionally veneered cannot be considered the material of first priority due to the pronounced risk for fracture of the framework and catastrophic fracture of the veneering material. Monolithic zirconia FDPs are a promising alternative to veneered implant-supported zirconia-ceramic FDPs. The mechanical stability of the translucent and shaded zirconia differs significantly between the grades of translucency. This must always be considered when clinical indications are recommended. As this specific area of prosthodontics is evolving fast, numerous studies evaluating different material options in implant prosthodontics are currently performed worldwide, and future consensus meetings will refine the present recommendations. The EAO will therefore regularly publish updated position papers on relevant topics. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the current evidence on the impact of surface finishing protocols (manual polishing vs glazing) on the color stability of in vitro pigmentation of CAD/CAM ceramics. Materials and Methods: Five electronic databases were searched on February 12, 2020. In vitro experimental studies were included based on the following PICO strategy: intervention = surface treatment of CAD/CAM ceramics with glazing agents; comparison = surface treatment of CAD/CAM ceramics with manual polishing; and outcome(s) = color stability. Two reviewers independently assessed the risk of bias. Results: Among 1,390 articles that were screened, 6 in vitro studies were considered for qualitative analysis. Five articles confirmed changes in the color of ceramics when they were immersed in pigmented solutions. One article investigated the color stability of samples after ultraviolet (UV) aging. Among the 6 studies analyzed, 4 showed clinically acceptable color alteration values (represented by ΔE) irrespective of the finishing protocol applied. Two articles presented clinically unsatisfactory color variation (ΔE > 3.3 and ΔE > 2.7) following mechanical polishing of a zirconia-reinforced lithium silicate ceramic. Coffee and red wine proved to be the beverages with the greatest potential for ceramic pigmentation. Only 1 article had a high risk of bias. Conclusion: For clinicians, most of the included studies demonstrated that both manual polishing and glaze application can prevent significant color alterations on CAD/CAM ceramic surfaces. However, due to the relatively limited amount of evidence to support this conclusion, further studies must be conducted. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the incidence of ultrathin ceramic veneer fractures with different preparation protocols over a period of 36 months and the possible relationship with local- and patient-related factors. Materials and Methods: Adult patients who received ceramic veneers for improvement in smile esthetics were selected from a private practice pool. Restorations were grouped as conventional (prep) or ultrathin ceramic veneers following either a minimal preparation (min-prep) or no tooth preparation (no-prep) protocol. After veneer bonding, all patients were followed up at intervals of 6 months up to 36 months. A panel of clinical outcomes was recorded, and patient satisfaction was assessed at 36 months. Results: The study sample was formed by 49 patients who received a total of 194 veneers. Twelve veneers were prep, 125 were min-prep, and 57 were no-prep. Total fracture occurrence was 9.8% in 13 participants. No fractures were observed in prep veneers, while 16 out of 125 min-prep and 3 out of 57 no-prep veneers had fractures. Most fractures (13 out of 19) occurred early, within the first 12 months after bonding. Out of 194 veneers, only 1 had a catastrophic failure (0.5%), 3 had large (≥ 1 mm) chippings (1.5%), and 15 had minor (< 1 mm) chippings (7.7%). A generalized estimating equation model revealed that the odds of veneer fracture were significantly higher in men (odds ratio [OR] = 11.29), in patients who exhibited tooth wear at baseline (OR = 5.54), and in central (OR = 13.56) and lateral (OR = 10.43) incisors compared to canines and premolars. All participants indicated that they would not change to a different restorative protocol in order to have a thicker restoration and possibly less risk of fracture. Conclusion: Ultrathin ceramic veneers are a viable cosmetic dentistry treatment option that involve minimal or no tooth preparation. However, a tendency for increased early fractures was observed in the min-prep group. [ABSTRACT FROM AUTHOR]

Purpose: To explore the effect of in situ synthesized particulates on a zirconia surface on the bonding properties between zirconia and porcelain.Materials and Methods: Presintered yttrium-stabilized tetragonal zirconia (Y-TZP) was cut into slices and bars and polished with 1,200-grit silicon carbide abrasive paper. Samples were randomly divided into six groups (C, I1, I3, I5, I7, and I9) according to immersion time in hydrofluoric acid solution (0, 10, 30, 50, 70, and 90 seconds, respectively). Then, the samples were placed in calcium chloride solution for 90 seconds and dipped in sodium hydroxide solution at 80°C for 2 hours. After sintering, the surface topography and roughness were examined. After the porcelain was fired, the bonding interface was observed, and cross-sectional microhardness was measured. The shear bond strength of the zirconia to porcelain was evaluated, and failure modes were classified. A 3-point bending test was applied to confirm the effects of the treatment on the mechanical properties. The above data were statistically analyzed.Results: Polycrystalline particulates were synthesized on the zirconia surface. The surface roughness values increased as the immersion time of the samples in hydrofluoric acid increased. The cross-sectional microhardness decreased gradually in the experimental groups. Group I7 showed an elevated bond strength (27.02 ± 2.44 MPa). Mainly mixed failure mode was obtained in the experimental groups. The Weibull characteristic strength for the experimental groups was higher than that of group C. The flexural strengths were not significantly different among the groups.Conclusions: In situ synthesized polycrystalline particulates on zirconia could effectively improve the bonding between zirconia ceramics and porcelain without significantly decreasing the mechanical properties. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of different extents of misfit between a restoration and the supporting implant on veneer fractures in screw-retained implant-supported metal-ceramic fixed dental prostheses (FDPs).Materials and Methods: A finite element analysis (FEA) model of a five-unit screw-retained metal-ceramic FDP supported by three implants was constructed, replicating a previous in vitro study. Eight different gap configurations at the single terminal implant, ranging from 0 to 150 μm, were tested. All setups were tested after clamping and with a load of 200 N applied. Maximum stress within the FDP was calculated.Results: The stress increased with each increase in misfit size above 30 μm, with the relationship between gap size and stress being linear up to 100-μm misfit. Above 100 μm, the stress increase accelerated. The stress pattern within the FDP changed with increasing gap size, confirming the findings of a previously conducted in vitro experiment for a misfit of 150 μm.Conclusion: The results of the FEA were in agreement with in vitro observations, validating the predictive value of FEA for technical complications. A misfit between an FDP and a supporting implant implies an increased risk of veneer fracture. Above a misfit of 30 μm, the stress levels are likely to be high enough to cause veneer fracture, and the risk increases disproportionately for misfit above 100 μm. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the wear of zirconia on natural teeth in humans in vitro and in vivo.Materials and Methods: Embase, the Cochrane Database, PubMed, and the Web of Science were searched (January 2014 to May 2019), and all references were retrieved. After preliminary screening of the literature, two researchers read the full texts of the remaining literature and determined whether the literature should be included. Data and information were extracted from the included literature, then analyzed and discussed.Results: A total of 49 in vivo experiments and 229 in vitro experiments were retrieved. After duplication removal and screening, 7 in vivo studies and 13 in vitro studies were included. The results of the in vitro studies showed that fine polished zirconia causes less antagonist wear on natural teeth than other treatments with zirconia or other restorative materials. The results of the in vivo studies showed the antagonist wear of zirconia on natural teeth was within the clinically acceptable range.Conclusion: Both in vivo and in vitro studies have shown polishing can reduce the wear of zirconia on natural teeth more than glazed or veneering porcelain. However, whether glazed zirconia causes less natural tooth wear after polishing is still a matter of debate. Due to the short observation period and heterogeneity of the experiment, the above conclusions should be carefully interpreted. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the microtensile bond strength (μTBS) of different CAD/CAM polymer-based ceramics to a repair composite resin using various bonding protocols.Materials and Methods: Three different CAD/CAM polymer-based ceramics (LAVA Ultimate [LU], 3M ESPE; VITA Enamic [VE], VITA Zahnfabrik; and CeraSmart [CS], GC) were used. Ceramic slices were obtained and subjected to thermal cycling between 5°C and 55°C for 5,000 cycles with a 30-second dwell time. The samples were randomly separated into the following groups: universal adhesive (UB); hydrofluoric acid (HF); sandblasting (SN); HF + UB; HF + ceramic primer (PR) + adhesive (GB); SN + UB; and SN + PR + GB. The repair composite resin (G-aenial Universal Flo, GC) was applied to the samples and subjected to re-aging between 5°C and 55°C for an additional 5,000 cycles. Parallel sections were removed from the specimens, and multiple beam-shaped micro sticks (1.0 mm × 1.0 mm × 10 mm) were prepared for each group. Subsequently, the μTBS test was performed, and the obtained data were statistically analyzed via one- and two-way analysis of variance and Tukey post hoc tests. Scanning electron microscopy (SEM) analysis was also performed.Results: Significant differences were found among the experimental groups (P < .05). The μTBS values of the UB bond groups were higher than those with the GB bond. The effect of pretreatment on μTBS (ηP2 = 0.556) was more significant than ceramic type (ηP2 = 0.481), and this result was supported by the SEM images.Conclusion: Pretreatment before application of universal adhesive is still needed to repair hybrid ceramic restorations with composite resins. [ABSTRACT FROM AUTHOR]

Purpose: To find proper ceramic thickness-cement combinations for color matching of high-translucency monolithic zirconia restorations.Materials and Methods: A total of 300 A2-shade high-translucency zirconia disk specimens of six different thicknesses (0.7, 0.9, 1.1, 1.4, 1.6, and 1.8 mm) were cemented to A3.5-shade composite resin backgrounds with five different cements: Temp-Bond, Zinc Phosphate, RelyX Unicem 2, PANAVIA SA Cement Plus, and GC Gold Label 1. Color measurements were conducted before and after cementation to determine the specimens' CIE L*a*b* values. ΔE00 values were calculated for specimens to assess color differences between before cementation and after cementation (ΔE1), between the A2 VITA classical shade (target) and specimens before cementation (ΔE2), and between the target and specimens after cementation (ΔE3). The ΔE3 values were compared with an acceptability threshold (ΔE00 = 1.8) to evaluate color matches. Data were analyzed using two-way analysis of variance, Bonferroni, and one-sample t tests (P < .05).Results: Mean ΔE3 values ranged between 1.0 and 3.4. Ceramic thickness, cement type, and their interaction affected the ΔE3 (P < .001). Temp-Bond with ceramic thickness of ≥ 1.1 mm and Zinc Phosphate with ceramic thickness of ≥ 0.9 showed color matches, but RelyX, PANAVIA SA, and GC did not show color matches with any tested ceramic thickness.Conclusion: Opaque cements with sufficient ceramic thicknesses created color matches for high-translucency monolithic zirconia restorations on A3.5-shade backgrounds. [ABSTRACT FROM AUTHOR]

Purpose: To assess the short-term outcomes of two different conservative preparation designs for posterior zirconia inlay-retained fixed dental prostheses (IRFDPs) and to analyze the marginal integrity of such restorations.Materials and Methods: Thirty patients with a missing maxillary first molar participated in this study and were divided randomly into two groups: one that received abutment preparations for inlay retainers (ID group, n = 20), including a proximal box and an occlusal extension, and one that received only proximal box preparations (PB group, n = 10). Zirconia IRFDPs were bonded in position and followed up after 2 weeks, 6 months, 1 year, and then annually. The in situ restorations were duplicated utilizing a single-step putty/wash impression technique at the 2-week and 2-year follow-up visits. Restoration margins were evaluated under scanning electron microscopy, and marginal continuity was calculated as a percentage of the whole margin at the tooth-cement (TC) interface and the zirconia-cement (ZC) interface.Results: After a mean observation period of 26.2 months, all restorations were still in function. The only complication encountered was debonding of restorations; however, they were re-bonded back in place without issue. The cumulative Kaplan-Meier 2-year survival rate for the IRFDPs was 86.6%. There was a significant difference between the two groups regarding percentage of continuous margins (P < .05) after 2 years, with the percentage of continuous margins in the ID group at 92.8% and 91.5% at the TC and ZC interfaces, respectively, and in the PB group at 84.1% and 78.6% at the TC and ZC interfaces, respectively.Conclusion: Zirconia-based monolithic IRFDPs can be recommended for short-term replacement of a single maxillary molar. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether high-level irradiance and short light exposure times with light-emitting diode (LED) curing units could provide bond strength comparable to halogen lights for ceramic laminate veneers (CLVs).Materials and Methods: A total of 160 extracted human maxillary central incisors were prepared to receive CLVs (lithium disilicate) in shades A1 and A3.5. CLVs were luted with light-curing (LC) and dual-curing (DC) resin cements using four protocols: 3 seconds in extra power mode, 8 seconds in high power mode, or 10 seconds in standard mode with an LED unit, or 40 seconds with a conventional halogen light from all aspects (n = 10). Following thermal cycles, shear bond strength test was performed with a universal testing machine. Data were analyzed using one-way analysis of variance and post hoc Tukey test. Failure modes were classified under a stereomicroscope, and data were analyzed using Pearson chi-square test (P = .050).Results: According to the intragroup comparison of different irradiation protocols, the mean shear bond strength of the A1-LC-10 group was found to be significantly higher than that of the A1-LChalogen group (P = .026). Shear bond strength values of the A1-LC-10 group and A3.5-LC-10 group were significantly higher than that of the A3.5-DC-10 group (P = .003). The A3.5-DC-3, A3.5-LC-3, and A1-DC-8 groups revealed the significantly most adhesive failures, and the A1-LC-8 group revealed the most mixed failures (P < .001).Conclusion: Both light and dark ceramic shades with LC cement combination responded the best to the standard mode of 10-second exposure time with LED application. However, with conventional halogen light application, the highest bond strength values were obtained with DC cement and light ceramic shade combination. [ABSTRACT FROM AUTHOR]

Purpose: To assess the success rates of cone beam computed tomography (CBCT) in identifying the locations and directions of abutment screw access holes (ASAHs) in metal-ceramic and all-ceramic implant restorations.Materials and Methods: Thirty-two implants were inserted into four clear acrylic casts. Metal-ceramic and all-ceramic crowns were placed on the inserted implants in two successive tasks. A maxillofacial radiologist determined the locations and angles of the ASAHs based on the CBCT images that were taken from the casts. Locations obtained from the CBCT images were carefully transferred to the crowns as access points. A prosthodontist pierced the crowns along the proposed access points and in the direction determined based on the CBCT images. Proper crown removal was considered to be the mark of success of CBCT in detecting ASAH location and direction. Fisher exact and chi-square tests were used to compare the results between the two types of restoration.Results: Success rates of CBCT for defining ASAH location and direction were, respectively, 96.9% and 93.8% in metal-ceramic restorations and 78.1% and 59.4% in all-ceramic restorations. There were no significant differences between the two restoration types regarding the detection of location in either molar (P = .333) or premolar (P = .226) crowns. Abutment angle did not affect the success rate of CBCT in determining ASAH location or direction in metal-ceramic restorations.Conclusion: CBCT images define the locations and directions of ASAHs in metal-ceramic restorations more reliably than in all-ceramic restorations. In contrast to the metal-ceramic crowns, the success rate of CBCT in all-ceramic crowns is more dependent on abutment angle and crown morphology. [ABSTRACT FROM AUTHOR]

Purpose: To systematically evaluate and compare the clinical performance of lithium disilicate (LDS)- and zirconium dioxide (ZrO2)-based ceramic monolithic crowns in the posterior dentition.Materials and Methods: Treatment was administered by two experienced general dental practitioners in two public dental health care clinics. Forty-four patients received 60 crowns randomized to be either LDS or ZrO2 and cemented with resin cement. Evaluations were performed after 3 years using California Dental Association criteria.Results: The mean follow-up time was 40 months (range: 31 to 50). No crown fractured during the observation time, and no chip-off fractures occurred. The success rate for ZrO2 was 80%, and the survival rate was 93.3%. For LDS, the success rate was 89.7%, and the survival rate was 100%. Survival after 3 years for all crowns together was 96.6%, and success was 84.7%. There was no significant difference between the two materials.Conclusion: Crowns made of monolithic translucent ZrO2 and LDS show equal and promising clinical results from a short-term perspective. There seems to be a difference between how patients and professionals rate crowns concerning esthetics (color and shape), with patients rating the restorations more favorably. [ABSTRACT FROM AUTHOR]

This clinical report presents the use of a modified polyetheretherketone (PEEK) post and core in order to support a lithium disilicate ceramic crown for a maxillary lateral incisor. When considering post-and-core restorations, material flexibility is essential to prevent root fractures. The low elastic modulus of PEEK (4 GPa) could result in lower root fracture rates, preserving tooth structure and favoring tooth re-restoration if the post fractures. PEEK is biocompatible, presents adequate bond strength with dentin when bonded with a resin cement, and can be used under ceramic restorations because of its white, esthetic color. PEEK posts and cores could also cost less when fabricated using common laboratory procedures. Polyetheretherketone (PEEK) posts and cores could be a viable alternative to rigid cast or zirconia posts, or even to fiber-reinforced composite posts, especially when combined with lithium disilicate crowns. [ABSTRACT FROM AUTHOR]

Purpose: To compare the marginal and internal gap values of different types of ceramic crowns fabricated based on digital and conventional impression methods. Materials and Methods: Ten noncarious extracted human teeth were prepared, and 60 restorations were made using six different impression and fabrication methods. Silicone replicas were obtained for marginal and internal gap evaluation. Statistical analyses were performed using Mann-Whitney U and Kruskal-Wallis tests (P < .05). Results: Statistically significant differences were found among various impression and fabrication methods. The smallest gap value was shown by the monolithic zirconia indirect digital scanning group (31.13 µm), and the largest for the lithium disilicate indirect digital scanning group (90.09 µm). Conclusion: The marginal and internal gap values of the restorations in the present study were 31.13 to 90.09 µm. The marginal and internal discrepancies of the tested materials were considered clinically acceptable. [ABSTRACT FROM AUTHOR]

Purpose: To measure the effect of simulated aging on stained resin-ceramic CAD/CAM materials regarding the durability of color and gloss. Materials and Methods: Test specimens (n = 15 per material) were prepared out of CAD/CAM ingots from two resin nanoceramics (Lava Ultimate [LVU], Cerasmart [CER]) and a polymerinfiltrated ceramic (ENA, VITA Enamic) stained with the manufacturer's recommended staining kit using photopolymerization. Control specimens were made of feldspathic ceramic (VITA Mark II [VM2]) and stained by means of ceramic firing. Negative control specimens (n = 15) (no staining) were prepared for each group. Color and gloss measurements were performed before and after each aging cycle by means of mechanical abrasion with a toothbrush. Groups were compared using Kruskal-Wallis test and paired post hoc Conover test. Changes within a group were calculated using Wilcoxon signed-rank test (α = .05). Results: The color difference (ΔE) was statistically significant for all stained CAD/CAM materials after simulated aging: CER (P < .001, 95% CI: 2.96 to 3.69), LVU (P = .004, 95% CI: 1.09 to 1.46), ENA (P = .004, 95% CI: 0.20 to 0.42), and VM2 (P < .001, 95% CI: 0.29 to 1.08). Aging resulted in a statistically significant increase in gloss in the LVU group (P < 0.001, 95% CI: 13.78 to 17.29), whereas in the ENA (P < .001, 95% CI: 7.83 to 12.72), CER (P < .001, 95% CI: 2.69 to 8.44), and VM2 (P = .014, 95% CI: 0.22 to 1.87) groups, a significant decrease in gloss was noted. Conclusion: Color and gloss of stained resin-ceramic CAD/CAM materials changed significantly after aging by means of toothbrush abrasion in vitro. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the shear bond strength (SBS) and color stability (ΔE) of four ceramic veneers (VITA VM 9; VITA VM 13; VITA VMK 95; and IPS e.max Ceram) following repair with three different self-adhesive composite resins (Fusio Liquid Dentin; Constic; and Vertise Flow) and BISCO Intraoral Repair Kit + Filtek Supreme (BC + FS).Materials and Methods: A total of 96 specimens were prepared per ceramic material, and each ceramic group was divided into subgroups according to testing method (32 specimens for color stability analysis and 64 specimens for SBS testing). ΔE and SBS (SBS1 = non-aged, SBS2 = thermally aged) values of the repaired specimens were calculated. One specimen from each of the thermally aged groups was investigated under scanning electron microscopy (SEM). Two-way ANOVA was used to analyze the mean ΔE, SBS1, and SBS2 values. The differences between SBS1 and SBS2 values were analyzed using independent-samples t test.Results: The lowest ΔE values were calculated for Constic (P ≤ .05). The SBS2 values among all groups were lower than the SBS1 values (P ≤ .05). The lowest SBS2 values were observed for Vertise Flow (2.3 ± 1.47 MPa) (P ≤ .05) and were below the acceptable limit of 5 MPa.Conclusion: All of the investigated repair materials in combination with the ceramic veneers exhibited ΔE values that were higher than the clinically acceptable limits. Thermal aging negatively affected the SBS values in all groups (P ≤ .05). All tested self-adhesive composite resins, with the exception of Vertise Flow, could be used instead of a repair kit with flowable composite resin, especially in noncooperative patients, for the purpose of repairing chipping fractures for VITA VM 9, VITA VM 13, and VITA VMK 95 (P > .05). [ABSTRACT FROM AUTHOR]

Purpose: To compare the influence of surface roughness and accelerated aging on the mechanical properties of polymer-based and ceramic CAD/CAM materials.Materials and Methods: Three polymers (Lava Ultimate [LVU], VITA ENAMIC [ENA], and Shofu Block HC [SFB]) and one ceramic (IPS Empress CAD [EMP]) were selected for this study. The specimens were treated with the aim of measuring surface roughness (Ra [mm]) and its influence on the mechanical properties. The treatments were: polishing (POL); etching with 9.6% hydrofluoric acid for 90 seconds (ETC); airborne-particle abrasion with 50-μm aluminum oxide at 2-bar pressure (SBT); and airborne-particle abrasion with 50-μm aluminum oxide at 2-bar pressure plus etching with 9.6% hydrofluoric acid (SAC) for 90 seconds. Before and after the accelerated aging (AA) protocol (30,000 cycles, 5°C and 55°C), the specimens were subjected to the 3-point bending test. The data were analyzed with two-way and three-way ANOVA and post hoc Tukey test (P < .05).Results: The surface roughness ranged from 0.24 μm to 1.96 μm, with statistically significant differences (P < .05). The highest surface roughness, in descending order, was exhibited by: LVU > SFB > EMP > ENA. The AA demonstrated an influence on the flexural strength of LVU, ENA, and SFB. The surface treatment did not affect the flexural moduli of the materials tested. The LVU and SFB showed decreased moduli of resilience after the AA; however, modulus of resilience was not influenced by surface treatment.Conclusion: The polymer-based materials were affected by AA. In addition, surface treatment could jeopardize their mechanical properties in certain conditions. [ABSTRACT FROM AUTHOR]

Purpose: To examine microwave heating for the purpose of ceramic glazing as an alternative to conventional methods in terms of color stability.Materials and Methods: Thirty disk-shaped specimens (11 × 2 mm) of VITA VM 9, VITA VM 13, VITA VMK 95, and IPS e.max Ceram veneers were prepared (n = 30 each). The specimens were further divided into three subgroups according to surface finishing procedure (polishing, conventional oven glazing, or microwave glazing [n = 10 each]). The related surface finishing procedure was applied according to the manufacturers' instructions. Color differences (ΔE) of the ceramic samples stored in a coffee solution at 37°C for 168 hours were determined using spectrophotometry. Data were analyzed using two-way ANOVA. The group differences were analyzed using Tukey HSD test.Results: Microwave-glazed specimens showed similar ΔE values to conventionally glazed specimens for the tested ceramics (P > .05). Polished specimens showed higher ΔE values than glazed specimens for the investigated ceramic materials, and the difference was significant for VITA VMK 95 and Vita VM9 (P ≤ .05).Conclusion: Microwave glazing has the advantage of decreasing glazing time to a few minutes and could be considered as an alternative method to conventional oven glazing and polishing with respect to color stability. [ABSTRACT FROM AUTHOR]

Purpose: To assess the 10-year clinical retention and survival rates of metal-ceramic (MC) and all-ceramic (AC) cantilever resin-bonded fixed dental prostheses (CRBFDPs).Materials and Methods: Forty CRBFDPs constructed from either cobalt-chromium ceramic (MC group; n = 20) or glass-infiltrated alumina ceramic (AC group; n = 20) were placed in 40 patients between August 2007 and December 2009. After baseline recordings, the patients were followed up using modified United States Public Health Services (USPHS) criteria after 6 months and thereafter annually for 10 years. Data were statistically analyzed using Kaplan-Meier estimation with log-rank (Mantel-Cox) test.Results: The 10-year clinical retention rate was 95.0% in the MC group and 70% in the AC group. The difference was statistically significant (P = .02, log-rank test). Three all-ceramic CRBFDPs fractured at 6, 12, and 84 months after insertion. No statistically significant difference in survival rate was observed between the MC and AC groups over the 10 years of clinical observation (MC: 100%; AC: 85%; P = .075) (Kaplan-Meier method, confidence interval = 92.5% to 97.5%).Conclusion: Although glass-infiltrated alumina ceramic anterior CRBFDPs exhibited a lower clinical retention rate compared to metal-ceramic CRBFDPs, the debonded prostheses were recemented and continued in function over the observation period. Additionally, an acceptable 10-year clinical longevity was recorded. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the impact of different veneering techniques on the fracture load of telescopic secondary crowns made of a high-performance polymer (Ultaire aryl ketone polymer [UAKP]).Materials and Methods: Zirconia primary crown models (taper of 0 degrees) were prepared (N = 48), polished, scanned, and divided into four veneering groups (n = 12 each): premanufactured, digital, full anatomical, and vestibular. For all groups except vestibular, a standardized telescopic secondary crown (thickness: 0.6 mm, circular margin: 1 mm) was constructed, adapted to the corresponding primary crown, milled from UAKP, and veneered. The veneered master crown was developed based on the premanufactured group. After surface polishing, all specimens were artificially aged in a chewing simulator (1.2 million cycles, 50 N, 1.1 Hz, between 5°C and 55°C). Fracture load was tested in a universal testing machine with a piston (Ø = 6 mm, 1 mm/minute). Fracture patterns were analyzed. For statistical analysis, Kolmogorov-Smirnov test and descriptive statistics followed by one-way ANOVA with post hoc Scheffé test were conducted (P < .05).Results: Significant differences in fracture load were found between different veneering techniques (P < .001), with the highest values for the vestibular and digital groups, followed by the premanufactured group. Full anatomical veneering showed the significantly lowest fracture load (1,885 ± 397 N). For all specimens, cohesive brittle fractures with similar fracture patterns occurred, irrespective of the veneering technique.Conclusion: The veneering technique of telescopic secondary crowns made of high-performance polymer affects overall stability. All veneering techniques provided sufficient fracture load values for telescopic secondary crowns made of UAKP. Digital veneers seem the most recommendable. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the clinical behavior of screw-retained monolithic lithium disilicate (LDS) implant-supported single crowns (ISSCs) over a 1-year follow-up.Materials and Methods: A total of 28 patients were restored with 45 screw-retained monolithic LDS (press-fabricated) ISSCs bonded to titanium bases in posterior sites. Modified United States Public Health Service criteria and Kaplan-Meier survival and success rates were evaluated.Results: A total of 27 patients with 44 ISSCs were evaluated 12 months (mean ± standard deviation: 13.02 ± 2.28) after prosthesis delivery. No implant or crown failures occurred. The Kaplan-Meier survival and success rates were each 100% after 1 year. Minorly increased surface roughness was noted in the occlusal contact point areas of 9 ISSCs (20.5% Bravo rating). Marginal adaptation, color match, and anatomical form stayed favorable over time.Conclusion: Press-fabricated LDS monolithic screw-retained implant crowns appear to be a promising treatment option for posterior implants under short-term observation. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of different concentrations of hydrofluoric acid (HF) on the surface roughness of a ceramic reinforced by lithium disilicate and on the bond strength formed between the ceramic and self-adhesive resin cement.Materials and Methods: A total of 100 disks of IPS e.max Press ceramic (Ivoclar Vivadent) reinforced by lithium disilicate were prepared as follows: group 1 remained untreated (control group); in groups 5-20, 5-40, and 5-60, the surfaces were etched with 5% HF for 20, 40, and 60 seconds, respectively; in groups 10-20, 10-40, and 10-60, the surfaces were etched with 10% HF for 20, 40, and 60 seconds, respectively; and in groups 10-20P, 10-40P, and 10-60P, the surfaces were etched with 10% HF for 20, 40, and 60 seconds, respectively, followed by treatment with 37% phosphoric acid for 5 seconds. Surface roughness and bond strength were analyzed with confocal microscopy and microshear testing, respectively. The values obtained were statistically analyzed using paired t test and two-way ANOVA followed by Tukey post hoc test at a 5% significance level.Results: Surface roughness was influenced by the concentration and exposure time of acid applied (P < .05) and by the combination of these two factors (P < .05). Treatment with 10% HF for 40 seconds (group 10-40) achieved the highest roughness value. In contrast, bond strength was affected only by the acid exposure time (P < .05).Conclusion: Conditioning of lithium disilicate ceramics can change the surface morphology, thereby affecting bond strength with resin cement. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical outcomes of monolithic CAD/CAM-fabricated polymer-infiltrated ceramic network (PICN) single crowns (SC) after 3 years.Materials and Methods: A total of 34 patients who received 76 single crowns were included in this cohort study. Full-coverage crown preparation with reduced thickness (1.0 to 1.5 mm) was applied. All monolithic PICN SCs (VITA Enamic) were manufactured using a CAD/CAM system and adhesively seated. Clinical follow-up evaluations were performed at 6, 12, 24, and 36 months after insertion using modified United States Public Health Service (USPHS) criteria. Kaplan-Meier survival and success methods were applied to calculate absolute and relative failures. To determine effects of time and restoration, a mixed logit model was adjusted for the modified USPHS criteria (P < .05).Results: PICN SCs revealed an estimated Kaplan-Meier survival rate of 93.9% after 3 years. Four clinically unacceptable fractures occurred, which resulted in replacement of the affected SCs. Neither secondary caries nor debonding were recorded. The 3-year Kaplan-Meier success rate was 92.7%. Significant increases in marginal discoloration (P = .0002) and surface roughness (P < .0001) were noted over time. Color match, anatomical form, and marginal adaptation remained favorable over the given observation period.Conclusion: PICN CAD/CAM crowns with reduced thickness showed acceptable survival and success rates over a service time of 36 months. However, extended clinical follow-up periods are needed to evaluate the long-term performance. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of different cements on the color outcomes of CAD/CAM lithium-disilicate implant crowns cemented to titanium-base abutments utilizing spectrophotometric analysis.Materials and Methods: A clinical situation with a missing lateral incisor was mimicked using a maxillary plastic model. Titanium-base-supported monolithic lithium disilicate crowns with identical designs were fabricated using a laboratory CAD/CAM system. The crowns were cemented with three provisional cements and with six definitive cements on both nonsandblasted and sandblasted titanium-base abutments for a total of 15 test groups. As a control group, identical crowns were attached with try-in paste on composite die abutments that duplicated the shape of the titanium-base abutments. The colors of the labial surfaces of the crowns and the peri-implant artificial soft tissue were measured with a spectrophotometer and recorded in CIE L*a*b* parameters. Color differences between the test and control groups were calculated as: ΔE = ([ΔL*]2 + [Δa*]2 + [Δb*]2)1/2. Kruskal-Wallis test was used to compare ΔE values across different groups.Results: The median ΔE values reported for crowns cemented with different definitive cements on titanium-base abutments ranged from 1.4 to 2.9 for the crown surface and from 1.7 to 1.9 on the peri-implant artificial soft tissue; when the titanium-base abutments were sandblasted, the respective median ΔE values ranged from 0.8 to 4.0 and from 1.4 to 2.2. Ceramic crowns cemented with Multilink HO 0 cement presented significantly (P < .01) lower ΔE values than the other cement types for the crown surface independent of sandblasting and for the artificial soft tissue surface when the titanium abutments were sandblasted (P = .011).Conclusion: Within the limitations of this study, Multilink HO 0 (Ivoclar Vivadent) cement showed the most favorable masking ability and the most favorable color outcome among the evaluated definitive cements. Cements of more opaque shades appeared in general to be more favorable in terms of masking the gray color of the titanium-base abutments. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the marginal and internal adaptations of ceramic inlay restorations placed with immediate dentin sealing (IDS) vs delayed dentin sealing (DDS) procedures.Materials and Methods: Mesial and distal Class II cavities were prepared in 12 extracted molar teeth, which were randomly allocated into six groups of 2 teeth each. Lava Ultimate inlays were fabricated and luted to the cavities using All-Bond universal adhesive system and eCEMENT dual-curing resin cement following IDS/immediate cementation (control groups 1 and 2), IDS/delayed cementation (groups 3 and 4), or DDS/delayed cementation (groups 5 and 6) protocols. Teeth in groups 2, 4, and 6 were subjected to thermocycling of 500 cycles between 5°C and 55°C after inlay cementation. Following staining with silver nitrate solution, the marginal and internal gap volumes were determined using microcomputed tomography images. Statistical analyses were conducted using independent t test and one-way analysis of variance followed by Tukey post hoc test (P < .05).Results: Marginal gap volume for DDS (1.856 ± 0.323 mm3) was significantly higher than that of IDS immediately after inlay cementation (0.891 ± 0.281 mm3) (P = .025). Following thermocycling, the internal gap volume for DDS (0.838 ± 0.248 mm3) was significantly higher than that for IDS (0.098 ± 0.066 mm3) (P = .000), but the marginal gap volume of DDS (1.964 ± 0.956 mm3) was not significantly different from that of IDS (1.426 ± 0.725 mm3) (P = .622).Conclusion: Luted ceramic inlays have a superior marginal adaptation right after cementation and a superior internal adaptation after thermocycling when using the IDS technique compared to the DDS technique. However, marginal adaptation after thermocycling was not significantly different between the two techniques. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the need for photoactivation of the adhesive system inside ceramic laminates before the luting procedure and to evaluate the color stability, nanohardness, and elastic modulus of the adhesive interface activated with singlewave and polywave light-curing units.Materials and Methods: A total of 44 lithium disilicate ceramic veneers (7.0 mm × 8.0 mm × 0.6 mm) were fabricated, bonded to enamel, and sorted into four experimental groups (n = 11 each) according to the type of light-curing unit (Radii-Cal [singlewave] or Valo [polywave]) and mode of adhesive system activation (with or without previous photoactivation). Two luting agents were used: the Tetric N-Bond adhesive system and Variolink Veneer resin cement. A visible ultraviolet spectrophotometer was used to evaluate the color stability before and after UVB artificial accelerated aging for 252, 504, and 756 hours (n = 8 samples from each group). A nanohardness tester under a load of 1,000 μN was used to evaluate the nanohardness and elastic modulus (n = 3 samples from each group). Data regarding the color stability and the mechanical properties (nanohardness and elastic modulus) were subjected to analysis of variance and Tukey protected least significant difference test (α = .05).Results: Prior activation of the adhesive system, the distinct light-curing units, and different aging periods exerted no significant difference on the color stability or mechanical properties of the resin cement (P > .05), except for in the group activated with Radii-Cal after 756 hours, in which the nonprevious activation showed lower color alteration compared to the previous photoactivation (P = .0285). Without prior activation of the adhesive with Valo, the polywave unit promoted higher nanohardness and elastic modulus values in the adhesive system (P < .05).Conclusion: In general, singlewave and polywave light-curing units promoted no difference in color stability or the mechanical properties of the adhesive interface. The prior curing of an adhesive system inside ceramic laminate is not necessary. [ABSTRACT FROM AUTHOR]

Purpose: To report on the 10-year clinical treatment outcomes for a strictly applied clinical protocol for pressable lithium disilicate glass-ceramic laminate veneers (LDLVs) placed by two experienced dentists.Materials and Methods: A 10-year follow-up assessment of 364 LDLVs placed in 41 patients was undertaken with the clinical criteria color/esthetic match of the porcelain surface, chipping and fracture occurrence, marginal discoloration, and integrity, assessed using the modified United States Public Health Service scoring system.Results: After 10 years, the survival rate was 97.4%. Complications occurred in 1.64% of the restorations (fractures and debonding in 0.55% and 1.09%, respectively).Conclusion: A strict, repeatable protocol for placing veneers with experienced dentists yielded good results. [ABSTRACT FROM AUTHOR]

Purpose: To assess the influence of a screw access hole (SAH) and mechanical cycling on the fracture load of implant-supported crowns (ISCs) manufactured with screw-retained (s) or cement-retained (c) abutments with either metal (M) or zirconia (Z) infrastructure.Materials and Methods: Six groups of restorations were made based on type of infrastructure (M or Z), fixation (s or c), and whether they underwent aging (a) with mechanical cycling: Zc, Zs, Zsa, Mc, Ms, and Msa. All ISCs were porcelain veneered and tested for compression to failure in distilled water (37°C) using a universal testing machine. ISCs from groups Zsa and Msa were mechanically cycled (106 cycles; 2 Hz, 100 N) in distilled water before compressive testing. Fractographic principles were followed to assess the fracture surfaces. The fracture load data were statistically analyzed using one-way analysis of variance and Tukey test (α = .05). The relationships between experimental group and failure mode were analyzed using chi-square test (α = .05).Results: Regardless of the infrastructure material, cement-retained ISCs (Zc and Mc) showed higher fracture load values than screw-retained ISCs (Zs, Zsa, Ms, and Msa) (P < .001), which were statistically similar to each other (P > .05). Aging had no effect on the fracture load of ISCs. There was a significant relationship between failure mode and experimental group (P < .001). Catastrophic fractures were found only in Zc and Zs. All metal-based ISCs failed from chipping reaching the metal infrastructure.Conclusion: Cement-retained ISCs showed higher fracture resistance than screw-retained prostheses. No catastrophic failures were found for metal-based ISCs. Aging did not affect the fracture load, but did affect the failure mode of ISCs. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of different combinations of self-adhesive resin cements and surface treatments on the microtensile bond strength (μTBS) of different CAD/CAM resin-matrix ceramics.Materials and Methods: Two different types of CAD/CAM resin-matrix ceramics (LAVA Ultimate [LU] and Vita Enamic [VE]) were used. Slices 5 mm in thickness were obtained from each CAD/CAM material. Samples of each ceramic were randomly separated into the following surface treatment groups: (1) Control group with no surface treatment; (2) 9.5% hydrofluoric acid (HF) + universal adhesive (UA, Single Bond Universal, 3M ESPE); and (3) Sandblasting with 50-μm aluminum oxide particles (SN) + UA. Two different types of recently developed resin cement (RelyX U200, 3M ESPE; SET PP, SDI Dental Limited) were applied to the treated ceramic slices in each group. After 24 hours, parallel sections were removed from the specimens, and microbeam-shaped sticks (1.0 × 1.0 × 10 mm) were prepared. The μTBS test was performed, and the data were statistically analyzed.Results: Statistical analyses revealed differences among the study groups (P < .05). The control groups of each resin cement exhibited lower μTBS values than the groups that received surface treatment (P < .05). The effect of surface treatment on μTBS (partial eta-squared [ηp2] = 0.381) was more significant than the effects of ceramic (ηp2 = 0.267) and self-adhesive resin cement (ηp2 = 0.184).Conclusion: Surface treatment is the most important factor affecting the μTBS of resin cement to CAD/CAM materials, followed by the type of resin-matrix ceramic and the type of resin cement, respectively. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate surface treatments for chipping in order to avoid bonding problems between hybrid materials and composite resin and to determine the optimal surface treatment method during intraoral repair of restorations to achieve clinical success.Materials and Methods: A total of 96 samples were prepared from computer-aided design/computer-assisted manufactured (CAD/CAM) blocks: 48 polymer-infiltrated ceramic (PIC) and 48 resin nano-ceramic (RNC). Prior to application of the surface treatments, the two test groups were each divided into four subgroups: control group; hydrofluoric acid group; hydrofluoric acid with silane group; and air-abraded with silica-coated aluminum oxide (Al2O3) sand with silane group. Each subgroup contained 12 samples. A shear bond strength (SBS) test was performed after artificial aging (5,000 cycles, 5°C to 55°C).Results: For both types of ceramic used, all subgroups showed significantly higher SBS values than the control groups (P < .05). The highest SBS values for both types of ceramic were observed in the air-abraded with silica-coated Al2O3 particles group.Conclusion: Each of the surface treatment methods increased the SBS, with the most effective method being air abrasion with silica-coated Al2O3. [ABSTRACT FROM AUTHOR]

Purpose: To assess the clinical performance of lithium disilicate single restorations on natural teeth.Materials and Methods: All patients who received lithium disilicate single restorations between 2009 and 2013 at the dental clinic of the University of Ferrara were recalled for clinical evaluation. A total of 43 partial and total restorations in 17 patients were evaluated from a minimum of 36 months follow-up to a maximum of 81 months follow-up, with a mean follow-up of 51 months.Results: The cumulative survival rate was 97.7%, and the cumulative success rate was 94.2%.Conclusion: Lithium disilicate can be successfully used for single-tooth restorations. [ABSTRACT FROM AUTHOR]

Purpose: Lithium disilicate (LDS) glass-ceramic restorations are routinely used, but results over a period longer than 10 years are rare. The objective of this study was to obtain long-term clinical data on monolithic LDS posterior crowns provided by a single restorative dentist.Materials and Methods: Eligible patients who received a circumferential LDS crown in the posterior region between 1997 and 2010 were invited to participate in a clinical examination in 2015. This consisted of intraoral inspection and radiographs, performed by one observer and according to standardized criteria. Probability of survival was estimated using Kaplan-Meier survival analysis.Results: A total of 13 patients (n = 87 restorations) fulfilled the inclusion criteria. Of these, 12 patients were available for clinical evaluation (n = 74 restorations). After 5, 10, and 15 years, the cumulative chance of survival of the restoration was 92%, 85.5%, and 81.9%, respectively, with a median observation period of 12.8 years. Of the 74 restorations, 13 failed: 4 because of secondary caries, 2 because of debonding, and 7 because of fracture of the restoration.Conclusion: Lithium disilicate can be regarded as a strong and fracture-load-resistant restorative material providing reliable long-term clinical performance. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the 5-year outcomes of glass fiber composite with cast posts and cores for the restoration of endodontically treated teeth.Materials and Methods: A total of 143 patients in need of 203 full ceramic restorations on endodontically treated teeth were included. After primary stratification based on the need for post or no post, teeth were randomly allotted to test group 1 (prefabricated glass fiber posts), 2 (custom-made glass fiber posts), or 3 (composite cores without posts). The control group was treated with gold alloy-based wrought posts and cast cores. Success (original present) and survival (present after intervention) probability lifetime curves, corrected for clustering, were drawn over the entire data set.Results: The mean follow-up time was 5.8 years (range: 0.5 to 7.2 years). At 5 years, the success and survival probabilities were 85.2% and 91.5%, respectively. Lifetime curves did not show any significant differences between the test and control groups for success (P = .85) or survival (P = .57). Moreover, no significant differences for success or survival could be found among the four groups (the three test groups and the control group).Conclusion: After 5 years of follow-up, cast gold and composite post-and-core systems on teeth with ceramic full restorations provided with a ferrule performed equally well. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether (1) the curing mode and (2) the use of the corresponding or noncorresponding crown luting system have an impact on the microleakage of computer-aided design/computer-assisted manufacture (CAD/CAM) composite crowns after chewing simulation.Materials and Methods: Two CAD/CAM composite blocks (Lava Ultimate [n = 20] and LuxaCam Composite [n = 20]) and their luting systems and curing modes (light curing [LC] or chemical curing [CC]) were investigated. A dye penetration test was used to detect the presence of microleakage.Results: Independently of the luting system, the LC groups showed a significantly lower microleakage compared to the CC groups (P < .05). Furthermore, the CC groups exhibited a reduction of microleakage if the CAD/CAM block and luting system were from the same manufacturer.Conclusion: For the CC mode, the corresponding block and luting system should be used. [ABSTRACT FROM AUTHOR]

Purpose: To assess whether particles from metal and other alloplastic materials detected in tissues surrounding dental implants could have other sources of origin besides biotribocorrosion or detachment from the implant surface.Materials and Methods: A total of 52 prostheses were randomly tested at various stages of manufacture. Identification of the detached microparticles was performed using light field microscopy and comparison with previously obtained microscopic images.Results: Microparticles of metallic, ceramic, plaster, polishers, or unidentifiable origin were detected in 49 prostheses (94%).Conclusion: Without an exhaustive decontamination protocol, prostheses and abutments carry metal microparticles and microparticles of other origins that could contribute to the development of peri-implant pathologies. [ABSTRACT FROM AUTHOR]

Purpose: To compare the marginal adaptation of monolithic high-translucency zirconia crowns and porcelain-veneered zirconia crowns.Materials and Methods: A master die was scanned to design and produce 10 porcelain-veneered zirconia copings for layering (PVZ group) and 10 monolithic high-translucency zirconia crowns (HTZ group). The mean vertical marginal gap in both groups was measured from eight predetermined points using a digital microscope.Results: The mean marginal gap in the PVZ group (39.62 ± 18.98 μm) was significantly higher than in the HTZ group (23.54 ± 7.57 μm) (P < .05).Conclusion: High-translucency monolithic zirconia crowns had better marginal fit than porcelain-veneered zirconia crowns. Both groups exhibited clinically acceptable marginal discrepancies. [ABSTRACT FROM AUTHOR]

Patients presenting both severe maxillary atrophy and dental malposition require a multidisciplinary treatment approach to achieve optimal esthetic and functional results. This case history report demonstrates how digital treatment planning and teeth set-up can serve as a reference for surgical, orthodontic, and prosthodontic procedures, leading to an all-ceramic full-arch implant-supported fixed prosthesis. [ABSTRACT FROM AUTHOR]