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ABSTRACT Objective Materials and Methods Results Conclusion Clinical Significance To evaluate the effect of staining, glazing, and polishing of stabilized zirconia with 5 mol% of yttrium oxide (5Y‐TZP) on the wear behavior of opposing tooth enamel.The plane specimens of 5Y‐TZP were divided into 6 groups (n = 10), according to surface treatment: as sintered, staining, glazing, polishing, staining followed by glazing, and staining followed by polishing, and positioned against tooth enamel during the two‐body wear test (20 N, 2 Hz, until completing 300,000 cycles). The wear rates of tooth enamel were evaluated using a profile projector and a digital pachymeter as a measure of vertical height loss. The data were analyzed by one‐way ANOVA and a Tukey post hoc test (α = 0.05).Polishing reduced the vertical height loss (p < 0.001) while there was no difference among other groups.Polishing is recommended as a finishing procedure to reduce the wear rates of tooth enamel, and finishing procedures (glazing or polishing) performed after staining did not affect the vertical height loss of tooth enamel.Polishing is the recommended finishing procedure for preshaded 5Y‐TZP to reduce the wear rates of opposing tooth enamel. Staining is applied to the occlusal surface to reproduce the pigmented groove appearance, and glazing or polishing performed after staining did not affect the wear rates of opposing tooth enamel. [ABSTRACT FROM AUTHOR]

Background: Zirconia (zirconium dioxide, ZrO2) has optimum properties for dental use. Its main advantages include biocompatibility, biomechanical stability, and high fracture resistance. This in vitro study aimed to determine and compare the hardness and density of conventional and monolithic zirconium after the laboratory sintering process. Methods and Results: This experimental-comparative study was carried out on processed samples of zirconia blocks, determining their mechanical properties and comparing them between different zirconia materials. Conventional zirconia blocks (from Dentsply Sirona Cercon HT and Orodent Zirconia HT) and monolithic zirconium blocks (from Dentsply Sirona Cercon ML and Orodent Zirconia Thor) were processed to produce 80 molar crowns. Samples were divided into two groups: Sirona[S]–Orodent[O]/Conventional [C] group (n=40) and Sirona[S]–Orodent[O]/Monolithic [M] group (n=40). Sirona samples were divided into Sirona-Conventional (SC) subgroup (n=20) and Sirona-Monolithic (SM) subgroup (n=20); Orodent samples were divided into Orodent-Conventional (OC) subgroup (n=20) and Orodent-Monolithic (OM) subgroup (n=20). Samples were formed with an occlusal thickness of 2mm and were sintered at 1450 °C for 2 hours. Hardness expressed in Vickers Hardness Number (VHN) was performed using a microhardness tester (Model HV-1000DT), and density determination (g/cm3) was performed with a pycnometer. The results showed no significant differences (P=0.137) between the Sirona manufacturer's SC and SM subgroups. The subgroups of the Orodent manufacturer showed statistically significant differences: the OM subgroup had a higher hardness value than the OS subgroup (1654.95±140.731 VHN versus 1526.45±149.011 VHN, P=0.008). Among the four studied subgroups, the highest hardness was in the OM subgroup (1654.95±140.731 VHN) compared to the SC subgroup (1595.55±147.790 VHN), OC subgroup (1526.45±149.011 VHN), and SM subgroup (1525.95±142.081 VHN) (P=0.016). Density in the subgroups SC, OC, SM, and OM was 6.246 g/cm3, 6.081g/cm3, 6.217 g/cm3, and 6.187 g/cm3, respectively, without statistically significant differences (P>0.05). Conclusion: The findings highlight the suitability of both zirconia materials from Dentsply Sirona and Orodent manufacturers for dental restorations, with Orodent monolithic zirconia offering potential advantages in terms of hardness.

Objective: To determine the median event-free survival and relative complication rates of monolithic and minimally layered full-arch zirconia prostheses, as well as to identify risk factors for prosthesis complications. Materials and Methods: In this retrospective cohort study, a total of 129 subjects (173 prostheses) were included in the chart review and 56 subjects (75 prostheses) participated in a clinical follow-up visit. All subjects had either single- or dual-arch monolithic or minimally layered zirconia implant-supported prostheses. Data related to patient, implant, and prosthesis factors were extracted from charts. The subgroup that presented for a clinical visit were asked to complete a satisfaction questionnaire. For this subgroup, the following clinical measures were assessed: routine intraoral examination, number of occluding units, cantilever length on each side of the prosthesis (right and left), prosthesis height, occlusal scheme, and oral hygiene methods. Periapical radiographs were obtained when the last radiographs of the patient were taken more than 12 months prior. Results: The follow-up period ranged from 12 months to 7.1 years (mean: 1.9 years). Observed complications included implant loss, peri-implantitis, mucositis, purulence, sinus tract formation, oroantral communication, implant fracture, titanium base debonding, ceramic chipping, prosthetic screw fracture or loosening, damage to opposing teeth, and clicking sounds. There was an insufficient number of complications to evaluate the effect of covariates on the risk of specific complications, such as titanium base debonding (eight events), ceramic chipping (nine events), and peri-implantitis (eight events). The unadjusted event-free median survival time was 5.8 years. The proportion of all prostheses with at least one complication was 30%. There were no observed prosthesis losses during the follow-up period. Conclusion: Monolithic and minimally layered zirconia full-arch implant-supported prostheses demonstrate an acceptable median event-free survival time. Event-free survival times were increased and the number of complications was reduced in prostheses with five to eight implants and conventional (as opposed to zygomatic) implants. There was a reduced hazard of complications with a regular recall regimen. Patient satisfaction with these prostheses was high. [ABSTRACT FROM AUTHOR]

Abstract Objectives This study aimed to evaluate the feasibility of monolithic zirconia laminate veneers (MZLV) compared to lithium disilicate laminate veneers (LDLV). Materials and methods Sixty resin replicas, each prepared with depths of 0.5 mm, 0.7 mm, and 1 mm, were produced using a 3D printer from acrylic teeth. Laminate veneers of these thicknesses were milled from pre-sintered monolithic zirconia (3rd generation) and lithium disilicate blocks. The intaglio surface of MZLV was treated with air abrasion using 110 μm diameter silica-modified aluminium oxide particles and ceramic primer, while LDLV was etched with etchant gel and treated with the ceramic primer before cementation with resin cement. Vertical marginal discrepancy (VMD) was assessed using a stereomicroscope, and a load-to-failure test was conducted using a universal testing machine. Failure modes were evaluated macroscopically on fractured surfaces. Data were analysed statistically using Two-way ANOVA and Bonferroni correction (α = 0.05). Results LDLV samples exhibited significantly larger VMD compared to MZLV samples across all thicknesses, especially in cervical, palatal, and mean data. Within the LDLV group, load-to-fracture values for 0.7 mm and 1.0 mm thicknesses were similar, whereas for 0.5 mm thickness, it was significantly lower. In the MZLV group, load-to-fracture values were lower for 0.7 mm and 1.0 mm thicknesses compared to LDLV, but higher for 0.5 mm thickness. Conclusions Material choice and restoration thickness significantly influence laminate veneer restorations’ success. MZLV generally exhibits superior vertical marginal fit compared to LDLV, with varying load-to-failure values across different thicknesses. Clinical management of debonding in MZLV is simpler compared to restoration fracture in LDLV. Clinical relevance Considering clinical factors, MZLV may be a preferable option to LDLV for this restoration with the thickness of 0.5 mm.

Abstract Background The translucency of different zirconia generations at each time point after thermocycling aging is still lacking. Methods Four zirconia materials were used with a total of 60 samples produced from monolithic third generation (5Y) 5 mol% yttria-stabilized zirconia polycrystalline ceramic and fourth generation zirconia (4Y) 4 mol% yttria-stabilized zirconia polycrystalline ceramic, represented by [group1:[CM-5Y] Ceramill Zolid fx (3rd generation zirconia) (Amann Girrbach, Koblach, Austria), group 2:[CM-4Y] Ceramill Zolid HT + (4th generation zirconia) (Amann Girrbach, Koblach, Austria), group 3:[CC-5Y] Cercon XT/ML (Dentsply Sirona, Germany) (3rd generation), and group 4:[CC-4Y] Cercon HT/ML (Dentsply Sirona, Germany) (4th generation)]. The L*a*b* figures were measured by using a spectrophotometer at baseline and after 10,000, 30,000, and 50,000 cycles of thermocycling. At each interval, the translucency of the samples was estimated by using the translucency formula CIEDE2000. The Scheffe post-hoc compared differences among each of the four materials. The Repeated measures ANOVA tested the differences between the materials at each of the different thermocycling intervals (p

Objectives: This study aimed to evaluate the feasibility of monolithic zirconia laminate veneers (MZLV) compared to lithium disilicate laminate veneers (LDLV). Materials and methods: Sixty resin replicas, each prepared with depths of 0.5 mm, 0.7 mm, and 1 mm, were produced using a 3D printer from acrylic teeth. Laminate veneers of these thicknesses were milled from pre-sintered monolithic zirconia (3rd generation) and lithium disilicate blocks. The intaglio surface of MZLV was treated with air abrasion using 110 μm diameter silica-modified aluminium oxide particles and ceramic primer, while LDLV was etched with etchant gel and treated with the ceramic primer before cementation with resin cement. Vertical marginal discrepancy (VMD) was assessed using a stereomicroscope, and a load-to-failure test was conducted using a universal testing machine. Failure modes were evaluated macroscopically on fractured surfaces. Data were analysed statistically using Two-way ANOVA and Bonferroni correction (α = 0.05). Results: LDLV samples exhibited significantly larger VMD compared to MZLV samples across all thicknesses, especially in cervical, palatal, and mean data. Within the LDLV group, load-to-fracture values for 0.7 mm and 1.0 mm thicknesses were similar, whereas for 0.5 mm thickness, it was significantly lower. In the MZLV group, load-to-fracture values were lower for 0.7 mm and 1.0 mm thicknesses compared to LDLV, but higher for 0.5 mm thickness. Conclusions: Material choice and restoration thickness significantly influence laminate veneer restorations' success. MZLV generally exhibits superior vertical marginal fit compared to LDLV, with varying load-to-failure values across different thicknesses. Clinical management of debonding in MZLV is simpler compared to restoration fracture in LDLV. Clinical relevance: Considering clinical factors, MZLV may be a preferable option to LDLV for this restoration with the thickness of 0.5 mm. [ABSTRACT FROM AUTHOR]

Increasing demand for adult orthodontic treatment using clear aligners has highlighted challenges in bonding clear aligner attachments to various restorations. Specifically, the bond strength of clear aligner attachments to glazed monolithic zirconia has not been extensively studied. This study aims to compare the shear bond strength (SBS) and mode of failure (MOF) of conventional bonding methods versus Superbond C&B (4-META/MMA-TBB resin cement) for clear aligner attachments on glazed monolithic zirconia. Fifty sintered and glazed zirconia samples were divided into five groups and attached with clear aligner attachments: Si (silane), B (bonding agent), SiB (bonding agent and silane), SU (Superbond C&B), and SiSU (silane and Superbond C&B). SBS and MOF of these samples were analyzed. Results indicated a significant difference in bond strength among the groups. SiSU exhibited the highest bond strength, followed by SU, while B had the lowest bond strength. SEM analysis revealed that SiSU and SU predominantly exhibited mixed failure, indicating high bond strength without affecting the glazed layers of the zirconia. In contrast, B exhibited only adhesive failure at the interface, resulting in insufficient bond strength for effective orthodontic treatment. In conclusion, using 4-META/MMA-TBB resin cement provides high bond strength for clear aligner attachments on glazed zirconia with minimal material damage during debonding. [ABSTRACT FROM AUTHOR]

The aim was to compare the effect of different endodontic surgical treatments on the stress distributions in dentin of a simulated first mandibular molar tooth using the finite element analysis method. Three surgical endodontic procedures (apical resection, root amputation, and hemisection) were simulated in a first mandibular molar. Biodentine or mineral-trioxide-aggregate was used to repair the surgery site in apical resection and root amputation models; the remaining root canal spaces were filled with gutta-percha. Access cavities were restored using resin composite. In hemisection model, root canal was filled with gutta-percha, and coronal restoration was finished with a monolithic zirconia crown. A sound tooth model was created as a control model. An oblique force of 300 N angled at 45° to the occlusal plane was simulated. Maximum von Mises stresses were evaluated in dentin near the surgery regions and the entire tooth. Apical resection/Biodentine and apical resection/mineral-trioxide-aggregate models generated maximum von Mises stresses of 39.001 MPa and 39.106 MPa, respectively. The recorded maximum von Mises stresses in root amputation models were 66.491 MPa for root amputation/Biodentine and 73.063 MPa for root amputation/mineral-trioxide-aggregate models. The highest maximum von Mises stress value among all models was observed in the hemisection model, measuring 138.87 MPa. Hemisection induced the highest von Mises stresses in dentin, followed by root amputation and apical resection. In apical resection, Biodentine and mineral-trioxide-aggregate did not show a significant difference in stress distribution. Biodentine in root amputation may lead to lower stresses compared to mineral-trioxide-aggregate. [ABSTRACT FROM AUTHOR]

The goal of the present study was to determine the minimum thickness of monolithic zirconia required to achieve an acceptable masking ability and to examine how brand, thickness, and abutment substrate influenced that masking ability (ΔE). Seventy-two A2-shade monolithic zirconia disc specimens in various thicknesses (1.0, 1.5, and 2.0 mm) were fabricated using three brands: Nacera® Pearl 1, DD cubeX2 and XTCERA TT. A spectrophotometer was used to determine the CIELab values of the specimens, which were placed on a D4-shade resin composite and white acrylic (control) substrates. The ΔE was calculated and compared with the acceptable (AT = 5.5) and perceptible (PT = 2.6) tolerance thresholds. Further investigation was conducted on 72-disc specimens from the monolithic zirconia brand with the best masking ability on D3-shade resin composite and semi-precious alloy. Using two-way ANOVA, the interaction of thickness, brand, and abutment substrate on ΔE was investigated. Nacera® Pearl 1 at 1.5 mm thickness was sufficient to achieve AT on a D4-shade resin composite substrate, whereas 2.0 mm of DD cubeX2 and XTCERA TT were required. Nacera® Pearl 1 further testing on two other substrates requires thicknesses of 1.5 mm and 1.0 mm, respectively. Only the Nacera® Pearl 1 group achieved PT on D3- and D4-shade resin composite (2.0 mm) and semi-precious alloy substrates (1.5 mm). Brand, thickness, and abutment substrate influenced the ΔE (p < 0.001). To achieve an acceptable masking ability, the minimum thickness of monolithic zirconia tested on D3- and D4-shade resin composite and semi-precious alloy should be around 1.5 mm to 2.0 mm. [ABSTRACT FROM AUTHOR]

To investigate how patterns generated by femtosecond (fs) laser and femtosecond laser power affect the surface roughness (Ra) and biaxial flexural strength (BFS) of monolithic zirconia. Eighty disk‐shaped zirconia specimens were divided into eight subgroups (n = 10): Control (C), airborne‐particle abrasion (APA), 400 mW fs laser (spiral [SP(400)], square [SQ(400)], circular [CI(400)]), and 700 mW fs laser ([SP(700)], [SQ(700)], [CI(700)]). Ra values were calculated by using a surface profilometer. One additional specimen per group was analyzed with scanning electron microscopy and x‐ray diffractometry. BFS values were obtained by using the piston‐on‐3‐ball test. One‐way ANOVA and either Tukey's HSD (BFS) or Tamhane's T2 (Ra) tests were used to evaluate data (α = 0.05). Regardless of the pattern and power, fs laser groups had higher Ra than C and APA, while SP groups had lower Ra than CI and SQ groups (p ≤ 0.004). For each pattern, Ra increased with higher laser power (p < 0.001), while the laser power did not affect the BFS (p ≥ 0.793). CI and SQ groups had lower BFS than the other groups (p ≤ 0.040), whereas SP groups had similar BFS to C and APA (p ≥ 0.430). Fs laser microstructuring with spiral surface pattern increased the Ra without jeopardizing the BFS of zirconia. Thus, this treatment might be an option to roughen tested zirconia. [ABSTRACT FROM AUTHOR]

Bu çalışmanın amacı, günümüzde son derece popüler olan yüksek translusensiye sahip monolitik zirkonya restoratif materyallerin mekanik ve optik özelliklerine dair sistematik bir derleme yapmaktı. Bu bağlamda MeSH, NIH-PubMed ve Google Academics elektronik veri tabanlarından “high translucent zirconia”, “optical properties”, “mechanical properties”, “translucency parameter”, “opalescence”, “fracture strength”, “toughness” anahtar kelimeleri kullanılarak elde edilen makaleleri derleyebilmek için elektronik arama yapıldı. Arama sonucunda tam metnine ulaşılan orijinal bilimsel makaleler veya derlemeler değerlendirmeye alındı. Buna karşın konuyla ilgili editörlere mektuplar, başyazılar ve kongre özetleri analiz dışı bırakıldı. Değerlendirmeye alınan makaleler incelendiğinde monolitik zirkonya restorasyonların optik özelliklerini iyileştirmek için materyale ait kompozisyon, yapı ve üretim yöntemlerinde pek çok modifikasyon yapılarak doğal dişle daha uyumlu estetik monolitik zirkonya seramiklerin üretildiği görülmüştür. Ancak optik özelliklerin iyileştirilmesi için yapılan işlemlerin materyalin mekanik özelliklerinde de değişikliklere sebep olduğu bilgisine ulaşılmıştır. Bu doğrultuda, yüksek translusent monolitik zirkonyaların optik ve mekanik özelliklerinin hekimler tarafından bilinmesi, klinik pratiğinde vaka için en uygun materyalin seçimi için büyük önem arz etmektedir.

Abstract Purpose The aim of the current study was to evaluate the effect of simulated gastric acid on the color and translucency of different indirect restorative materials. Materials and methods A total of 36 disc-shaped samples were cut by using an isomet saw and divided into four equal groups (n = 9) according to the material type: Group Z: translucent zirconia (Ceramill® Zolid ht.+ preshade, Amann Girrbach, Koblach, Austria); Group E: lithium disilicate (IPS e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein); Group C: resin nanoceramic (Cerasmart, GC, Tokyo, Japan); Group P: polyether ether ketone (PEEK) (Bettin Zirconia Dentale Italy) veneered with indirect high impact polymer composite (HIPC) (breCAM HIPC, Bredent GmbH & Co. KG, Germany). The samples were immersed in simulated gastric acid (HCl, pH 1.2) for 96 hours at 37 °C in an incubator. The color change (ΔE00) and translucency (RTP00) were measured every 9.6 hours (one-year clinical simulation) of immersion in simulated gastric acid. Results For color change (∆E00) and translucency (RTP00) among the tested materials, there was a highly statistically significant difference (P

Background/purpose: Translucent monolithic zirconia restorations have recently introduced. The purpose of this study was to evaluate the clinical behavior and the survival rate of the posterior third-generation monolithic zirconia crowns (MZCs) during three years of clinical service. Materials and methods: Twenty-four patients who needed thirty crowns were enrolled in this study. Digital impressions were made, and the crowns were milled and cemented with a resin cement. The crowns outcomes were assessed using the California Dental Association's (CDA) criteria. Gingival index (GI), plaque index (PI), and periodontal probing depth (PPD) for MZCs and contralateral natural teeth (control) were assessed. Margin index (MI) for MZCs was also assessed. Data analysis was conducted using the Wilcoxon signed-rank and the Friedman tests. Results: The 3-year survival rate was 100%. All MZCs were rated as satisfactory throughout the follow-up period, and no biological or mechanical complications were observed. No differences were recorded when GI, PI and PPD at 3-year of follow-up were compared to baseline. No differences were recorded between crowned and control teeth. The MI remained stable throughout the study period. Conclusion: The third-generation monolithic zirconia appears to be a good treatment option for the rehabilitation of posterior single teeth.

Abstract Background Recent forms of translucent zirconia material have been developed, offering a wide range of options and varieties for enhancing aesthetics, making it a preferred choice in the field of prosthetic dentistry. However, there is insufficient understanding regarding the recent types of zirconia materials and their optical behavior. Understanding the variables that influence the translucency of zirconia and identifying strategies to enhance its esthetics are crucial. Purpose The current systemic review highlights a comprehensive understanding of different zirconia generations in relation to their optical characteristics and evaluates material-related variables affecting their translucency. Methods The present review studied in-vitro studies that evaluated the optical characteristics of different yttria content of yttria stabilized materials. The topics explored were: (1) the different zirconia material generations and their optical behavior; (2) material-related factors that affect their translucency. The research was restricted to online publication in the English language from July 1, 2010, to July 31, 2023, using PubMed, Scopus, and Science Direct resources. The search key terms and their combinations were “zirconia,” “translucent zirconia,” “cubic zirconia,” “highly translucent zirconia,” “yttria partially stabilized zirconia,” “monolithic zirconia,” “translucency,” “optical properties,” and “light transmission.” Results The data obtained from fifty-three studies addressed the optical characteristics of various zirconia generations. They reported that changing yttria content had a significant impact on translucency. Different kinds of zirconia ceramics of the same generation have varying translucencies. Achieving optimum aesthetics with monolithic zirconia is challenging due to factors related to material aspects such as the presence of additives, point defects, microstructure, thickness, phase distribution, and sintering conditions. Conclusions Newly developed monolithic dental zirconia ceramics have improved aesthetics and translucency. However, additional research is necessary to evaluate their performance and long-term durability. Trial Registration This systematic review was registered in PROSPERO, under number CRD42023474482.

Purpose: The aim of the current study was to evaluate the effect of simulated gastric acid on the color and translucency of different indirect restorative materials. Materials and methods: A total of 36 disc-shaped samples were cut by using an isomet saw and divided into four equal groups (n = 9) according to the material type: Group Z: translucent zirconia (Ceramill® Zolid ht.+ preshade, Amann Girrbach, Koblach, Austria); Group E: lithium disilicate (IPS e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein); Group C: resin nanoceramic (Cerasmart, GC, Tokyo, Japan); Group P: polyether ether ketone (PEEK) (Bettin Zirconia Dentale Italy) veneered with indirect high impact polymer composite (HIPC) (breCAM HIPC, Bredent GmbH & Co. KG, Germany). The samples were immersed in simulated gastric acid (HCl, pH 1.2) for 96 hours at 37 °C in an incubator. The color change (ΔE00) and translucency (RTP00) were measured every 9.6 hours (one-year clinical simulation) of immersion in simulated gastric acid. Results: For color change (∆E00) and translucency (RTP00) among the tested materials, there was a highly statistically significant difference (P < 0.001) after every year of follow-up. The color change in both Z and G groups was the lowest after 1 year of acid immersion, followed by that in group H, and the highest change in color was recorded in group P. Conclusion: High translucent zirconia is recommended in patients who are concerned about esthetic, especially with acidic oral environment. [ABSTRACT FROM AUTHOR]

Translucent monolithic zirconia restorations have recently introduced. The purpose of this study was to evaluate the clinical behavior and the survival rate of the posterior third-generation monolithic zirconia crowns (MZCs) during three years of clinical service. Twenty-four patients who needed thirty crowns were enrolled in this study. Digital impressions were made, and the crowns were milled and cemented with a resin cement. The crowns outcomes were assessed using the California Dental Association's (CDA) criteria. Gingival index (GI), plaque index (PI), and periodontal probing depth (PPD) for MZCs and contralateral natural teeth (control) were assessed. Margin index (MI) for MZCs was also assessed. Data analysis was conducted using the Wilcoxon signed-rank and the Friedman tests. The 3-year survival rate was 100%. All MZCs were rated as satisfactory throughout the follow-up period, and no biological or mechanical complications were observed. No differences were recorded when GI, PI and PPD at 3-year of follow-up were compared to baseline. No differences were recorded between crowned and control teeth. The MI remained stable throughout the study period. The third-generation monolithic zirconia appears to be a good treatment option for the rehabilitation of posterior single teeth. [ABSTRACT FROM AUTHOR]

It has been observed in recent years that zirconia (Zr) is being increasingly used for a wide range of clinical applications. There are several reasons for this, but the most significant one is its excellent mechanical properties, specifically its transformation toughening properties compared to other dental ceramics and its improved natural appearance when compared to ceramometal restorations. As a result of the advancement of chairside milling and developments in rapid-sintering technology, the fabrication of dental restorations has become more computerized, time-saving, and accurate over the past few decades. However, a main disadvantage of conventional Zr restorations is that they lack the translucency of glass–ceramics, although they are extremely strong. Recently, by increasing the yttrium %, changing the grain size, and reducing the impurities, the ultra-translucent monolithic zirconia "5-mol%-yttria-stabilized tetragonal zirconia polycrystals" has been introduced, with successful attempts to make translucent Zr an aesthetically attractive option for minimally invasive veneer restorations. It is important to note that veneer restorations do not possess the mechanical retentive features of the tooth preparations and rely primarily on bonding to resin cement. This presents a great challenge for the inert Zr since it does not bond chemically with resin cement, unlike glass–ceramic materials that establish chemical adhesion with resin cement, favoring their use for indirect veneer restorations. Taking this into account, this article aims to review the progressive development of ultra-translucent monolithic Zr materials as they are available today and, in the future, represents a concerted drive toward maximum translucency and strength, which renders them a viable treatment option for esthetic veneer restorations. [ABSTRACT FROM AUTHOR]

IntroductionEvaluating the fracture resistance of dental ceramics such as monolithic zirconia crowns is crucial for assessing their durability. Conventional destructive laboratory tests often fail to accurately evaluate the timing and failing crack formation of these brittle materials. Non-destructive testing methods, such as acoustic emission testing (AET), offers an alternative by providing valuable data on material properties without causing damage to the samples.The in vitro study aimed to evaluate the sensitivity of a sound harvesting modified acoustic emission testing by comparing the fracture resistance of posterior monolithic zirconia crowns (MZCs) measured via the modified set up with that of a conventional fracture toughness test.Material and methodsA modified acoustic emission set up, the sound harvesting test (SHT), featuring a condenser microphone, an amplifier, a custom audio chipset and a cut-off switch integrated into a universal testing machine, was compared to a conventional fracture toughness test to measure fracture loads on 50 posterior monolithic zirconia crowns divided in two groups.ResultsThe sound harvesting test recorded a mean fracture load of 1,108.99 N, significantly less than the 1,292.52 N measured with the conventional test, indicating a more sensitive detection of fractures. Statistically significant differences (p

It has been observed in recent years that zirconia (Zr) is being increasingly used for a wide range of clinical applications. There are several reasons for this, but the most significant one is its excellent mechanical properties, specifically its transformation toughening properties compared to other dental ceramics and its improved natural appearance when compared to ceramometal restorations. As a result of the advancement of chairside milling and developments in rapid-sintering technology, the fabrication of dental restorations has become more computerized, time-saving, and accurate over the past few decades. However, a main disadvantage of conventional Zr restorations is that they lack the translucency of glass–ceramics, although they are extremely strong. Recently, by increasing the yttrium %, changing the grain size, and reducing the impurities, the ultra-translucent monolithic zirconia “5-mol%-yttria-stabilized tetragonal zirconia polycrystals” has been introduced, with successful attempts to make translucent Zr an aesthetically attractive option for minimally invasive veneer restorations. It is important to note that veneer restorations do not possess the mechanical retentive features of the tooth preparations and rely primarily on bonding to resin cement. This presents a great challenge for the inert Zr since it does not bond chemically with resin cement, unlike glass–ceramic materials that establish chemical adhesion with resin cement, favoring their use for indirect veneer restorations. Taking this into account, this article aims to review the progressive development of ultra-translucent monolithic Zr materials as they are available today and, in the future, represents a concerted drive toward maximum translucency and strength, which renders them a viable treatment option for esthetic veneer restorations.

This study aims to assess and compare the impact of Monolithic Zirconia (MZ) and In-Ceram Zirconia (ZP) superstructures on stress distribution within implants and D2/D4 bone densities under 200 N vertical and oblique occlusal loads using three-dimensional finite element analysis via ANSYS WORKBENCH R2. The analysis employed maximum and minimum von Mises stress values. Modeling an implant (4.2 mm diameter, 10 mm length) and abutment (0.47 mm diameter), with an 8 mm diameter and 6 mm length single crown, the research identified lower von Mises stresses in D2 cancellous bone with the MZ model under vertical loading. Conversely, under oblique loading, the ZP model exhibited maximum von Mises stresses in D4 bone around the implant. This underscores the critical need to consider physical and mechanical properties, beyond mere aesthetics, for sustained implant success. The findings highlight the effect of material composition and stress distribution, emphasizing the necessity of durable and effective implant treatments.

Introduction: Amelogenesis imperfecta (AI) is a diverse collection of inherited diseases that show quantitative and qualitative defects in tooth enamel in the absence of systemic manifestations. Patients with AI often have open bite, which also requires complex care. In the final dental treatment, the focus should be on the preparation of indirect restorations, so early detection and care can be key factors for long-term success, as poor-quality enamel can be more easily attacked by caries. Case report: A 15-year-old young female patient presented to the Department of Prosthodontics of Semmelweis University in 2022 because of her worn down teeth due to amelogenesis imperfecta. The patient also had open bite. During the intraoral examination, reduced enamel was detected on all teeth, with partial enamel breakdown, exposing the dentin. Following the current professional recommendations, we planned monolithic zirconia crowns and splints as well as bridges to correct the tooth gaps on the upper and lower arches. In the first phase of the treatment, we increased the occlusal vertical dimension using a gothic arch tracer and digital face bow (Zebris for Ceramill). The impressions were taken by the 3Shape Trios 3 Pod, making it more comfortable for the patient and easier to copy accurately the increased occlusal vertical dimension from the temporary restoration to the final restoration. Due to the damaged tooth structure, for the final cementation resin modified glass ionomer was used. Protecting the monolithic zirconia restorations, the temporomandibular joint and the muscles, a Michigan-splint was created for the patient. Summary: For patients with AI, the appearance of the teeth can cause psychological and functional problems, so the goal of every treatment plan is restoration, and regular follow-up. Maintaining proper oral hygiene is also essential for patients with AI, and according to the literature, treatment with indirect restorations increases success compared to direct treatments.

Introduction: Dentinogenesis imperfecta (DI) is a genetic disease that affects the dentin of the teeth. The autosomal dominantly inherited disease affects only the tissues of connective tissue (mesodermal) origin of the teeth, so there are no changes in the enamel and the periodontium. Due to poor quality dentin, the teeth become discolored and the enamel easily peels off. In the dental treatment of patients with DI, the focus should be on indirect restorations as soon as possible, so the dentist must diagnose the condition as early as possible so that the possibility of early intervention is realized, as well as balancing the decision for early intervention with the long-term survival of the restorations. Case report: A 15-year-old young male patient came to the Department of Paediatric Dentistry and Orthodontics of Semmelweis University, to have the veneers on his lower incisors replaced. He also wanted a comprehensive aesthetic rehabilitation. The anamnesis revealed that the patient’s father also suffers from DI, and the patient lives with hemophilia A. Based and the literature evidence and recommendations, we planned indirect restorations. The decreased occlusal vertical dimension was increased; in the first phase to adapt the neuromuscular system to the increased vertical dimension, polymethyl-methacrylate (PMMA) restorations were prepared. After the patient both aesthetically and functionally having been satisfied with the temporary restorations, the final restoration were planned as a monolithic zirconia crowns and splints for the upper and lower arches. For the cementation resin modified glass ionomer was used to avoid the adhesive technique, which is not recommended in such cases. The prosthodontic phase was preceded by professional oral hygiene treatment, instruction, and motivation. Summary: For patients with DI, the key is the early diagnosis and its treatment is essential. Scientific evidence indicates that indirect restorations should be preferred over direct ones in patients with DI. Close cooperation with the hematologist is necessary during the treatment of the patient with hemophilia A.

Purpose: This in vitro study evaluated technical outcomes of monolithic zirconia implant-supported fixed dental prostheses (iFDPs) supported by different designs of titanium base abutments after aging and static load testing. Materials and Methods: Sixty three-unit monolithic zirconia (yttrium oxide partially stabilized tetragonal zirconia polycrystals; Y-TZP)iFDPs were produced and divided into four groups: group A—conical titanium base abutments for the prosthesis; group B—cylindrical titanium base abutments for the crown; group C—conical titanium base abutment for the prosthesis and cylindrical titanium base abutment for the crown; group D—cylindrical titanium base abutments for the prosthesis. The samples were subjected to an aging protocol and to continuous static loading until failure and analyzed visually and with specific software. The technical outcomes comprised the occurrence of debonding, screw loosening, deformation and fracture, abutment deformation and fracture, implant deformation and fracture, zirconia chipping and fracture, and bending moments. The Pearson chi-squared test (χ2) and Fischer exact test were used to compare the outcomes. The Kolmogorov-Smirnov test was used to evaluate data distribution of the bending moments. Analysis of variance (ANOVA) was used for the analysis of parametric data distribution, and the Kruskal-Wallis test was used for nonparametric data distribution. Results: After aging, a higher percentage of debonding (P = .042) and micromovement (P = .034) was recorded in group C (P = .042). The conical titanium base abutments had a higher debonding (P = .049) and a higher macromovement rate (P = .05). The static load test showed higher bending moments in group D (P = .001) and lower bending moments in group A (P = .001). Debonding was highest in group C (P = .001) and lowest in group A (P = .002). Complete loss of retention rate was highest in group C (P = .001). The conical titanium base abutment had the highest debonding rate (P = .001) and complete loss of retention (P = .001). The micromovement rate was the highest for cylindrical titanium base abutments for the crown (P = .001). The lowest screw loosening, zirconia chipping, and fracture rate (P = .001) and the highest screw deformation (P = .004) were recorded in group A. The screw deformation rate was lowest in the cylindrical titanium base abutments for the crown (P = .008). Conclusion: The mixed titanium base abutment design comprising one conical and one cylindrical abutment in Y-TZP iFDPs led to the highest debonding rate. The cylindrical titanium base abutment for the prosthesis provided a lower percentage of debonding and the highest load resistance. [ABSTRACT FROM AUTHOR]

This study aims to assess and compare the impact of Monolithic Zirconia (MZ) and In-Ceram Zirconia (ZP) superstructures on stress distribution within implants and D2/D4 bone densities under 200 N vertical and oblique occlusal loads using three-dimensional finite element analysis via ANSYS WORKBENCH R2. The analysis employed maximum and minimum von Mises stress values. Modeling an implant (4.2 mm diameter, 10 mm length) and abutment (0.47 mm diameter), with an 8 mm diameter and 6 mm length single crown, the research identified lower von Mises stresses in D2 cancellous bone with the MZ model under vertical loading. Conversely, under oblique loading, the ZP model exhibited maximum von Mises stresses in D4 bone around the implant. This underscores the critical need to consider physical and mechanical properties, beyond mere aesthetics, for sustained implant success. The findings highlight the effect of material composition and stress distribution, emphasizing the necessity of durable and effective implant treatments. [ABSTRACT FROM AUTHOR]

PURPOSE. To evaluate the metameric disparities among monolithic zirconia materials with differing yttrium compositions across various lighting conditions. MATERIALS AND METHODS. Thirty-six square-shaped zirconia samples measuring 10 × 10 × 0.5 mm were prepared from monolithic zirconia materials with three different yttrium contents. A 0.2 mm thick layer of polymerized dualpolymerizable self-adhesive resin cement was created using a silicone mold with the same dimensions as the prepared zirconia specimens. To evaluate metamerism, color measurements were conducted using a spectrophotometer device on a neutral gray background in a color measurement cabinet that offers four different illumination environments. All samples underwent aging by subjecting them to 10000 thermal cycles using a thermal cycle tester. Following thermal aging, color measurements were taken once more, and the data were recorded using the CIE L*, a*, b* color system. Two-way ANOVA and Post-hoc Bonferroni tests were employed to analyze the data. RESULTS. It was observed that there was no statistical difference among the color measurements made in different illumination environments of the monolithic zirconia ceramics used to evaluate metamerism (P > .05). This observation remained consistent both before and after thermal aging. After thermal aging, the color of monolithic zirconia materials exhibited a tendency towards red and yellow hues, accompanied by a decrease in brightness levels. CONCLUSION. It can be stated that different illumination conditions did not affect the metamerism of monolithic zirconia materials, but there was a color change in monolithic zirconia materials after a thermal aging period equivalent to one year. [ABSTRACT FROM AUTHOR]

Objective: This article highlights a CAD/CAM complete‐mouth rehabilitation in an 82‐year‐old patient by means of a complete maxillary prosthesis and mandibular implant‐ and tooth‐supported fixed restorations made from multilayered zirconia. Clinical Considerations: Comprehensive complete‐mouth rehabilitations in elderly patients with adaptation of the occlusal vertical dimension (OVD) often present particular challenges. This applies especially when exacting functional and esthetic requirements are to be met and the treatment should not cause the patient too much effort, still ensuring the highest level of quality and efficiency and a low intervention rate. Conclusion: The digital approach used for the present patient allowed for an efficient treatment procedure, facilitated virtual evaluations using a face‐scan, and enhanced the predictability of the prosthodontic outcome. The approach enabled some steps required in the conventional protocol to be omitted, resulting in a straightforward clinical treatment with minimal strain on the patient. Clinical Significance: Because of the comprehensive recording of extraoral and intraoral data, for example with a facial scanner, it was possible to transfer a digital replica of the patient to the dental laboratory technician. With this protocol, many steps can be performed in the absence of the real patient. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to compare failure load and initial damage in monolithic, partially veneered, and completely veneered (translucent) zirconia cantilevered fixed partial dentures (CFPDs), as well as completely veneered metal-ceramic CFPDs under different support and loading configurations. Materials and methods: Eight test groups with anatomically congruent CFPDs (n = 8/group) were fabricated, differing in CFPD material/support structure/loading direction (load applied via steel ball (Ø 6 mm) 3 mm from the distal end of the pontic for axial loading with a 2-point contact on the inner cusp ridges of the buccal and oral cusps and 1.3 mm below the oral cusp tip for 30° oblique loading): (1) monolithic zirconia/CoCr abutment teeth/axial, (2) monolithic zirconia/CoCr abutment teeth/oblique, (3) partially veneered zirconia/CoCr abutment teeth/axial, (4) partially veneered zirconia/CoCr abutment teeth/oblique, (5) completely veneered zirconia/CoCr abutment teeth/axial, (6) completely veneered CoCr/CoCr abutment teeth/axial (control group), (7) partially veneered zirconia/implants/axial, and (8) partially veneered zirconia/natural teeth/axial. Restorations were artificially aged before failure testing. Statistical analysis was conducted using one-way ANOVA and Tukey post hoc tests. Results: Mean failure loads ranged from 392 N (group 8) to 1181 N (group 1). Axially loaded monolithic zirconia CFPDs (group 1) and controls (group 6) showed significantly higher failure loads. Oblique loading significantly reduced failure loads for monolithic zirconia CFPDs (group 2). Initial damage was observed in all groups except monolithic zirconia groups, and fractography revealed design flaws (sharp edges at the occlusal boundary of the veneering window) in partially veneered zirconia CFPDs. Conclusions: Monolithic zirconia CFPDs might be a viable alternative to completely veneered CoCr CFPDs in terms of fracture load. However, oblique loading of monolithic zirconia CFPDs should be avoided in clinical scenarios. Design improvements are required for partially veneered zirconia CFPDs to enhance their load-bearing capacity. Clinical relevance: Monolithic zirconia may represent a viable all-ceramic alternative to the established metal-ceramic option for CFPD fabrication. However, in daily clinical practice, careful occlusal adjustment and regular monitoring should ensure that oblique loading of the cantilever is avoided. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the survival, success rates, and biological and technical complications of three-unit posterior monolithic and veneered zirconia and metal-ceramic (MC) posterior fixed partial dentures (FPDs) fabricated using a digital workflow and computer-aided design and computer-aided manufacturing (CAD/CAM) over a 5-year followup. Methods: Ninety patients in need of three-unit posterior FPDs were randomized to receive monolithic zirconia (MZ), veneered zirconia (VZ), and MC restorations (n = 30 each). Teeth preparations were scanned using an intraoral scanner, and restorations were milled and cemented with resin cement. Clinical performance and periodontal parameters were assessed at baseline and yearly up to 5 years after insertion. Data analysis was performed using the Kaplan-Meier method, Friedman test, and Wilcoxon signed-rank test with Bonferroni correction and Mann-Whitney U test. Results: The 5-year survival rates of the MZ, VZ, and MC FPDs were 87%, 97%, and 100%, respectively (P = 0.04). Most complications were biological in nature. Only one MZ FPD fractured 58 months after placement. All the restorations were assessed as satisfactory at each recall. Differences were found in the gingival index score over time in the VZ and MC groups. The margin index remained stable throughout the follow-up period in both zirconia groups. Conclusions: The results of this study suggest that using a digital workflow to fabricate posterior FPDs is an adequate treatment option and that monolithic zirconia could be a viable alternative to metal-ceramic or veneered zirconia. However, further long-term studies are necessary to provide stronger evidence in patients with bruxism. [ABSTRACT FROM AUTHOR]

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Introduction:The accumulated experience until now, has demonstrated that, when applying a prosthetic restoration on teeth or on an implant support, complications of a technical nature occur much more frequently than those of a biological nature. Phenomena such as the corrosion of the metal supporting structure (framework) or the exfoliation of the veneering ceramics or even the invoice on these structures, with the unaesthetic visualization of the metal, are the most frequent. Purpose: Highlighting the disadvantages of restorations on CR-CO metal support compared to those made of monolithic zirconia. The advantages of modern technology that add considerable improvement in aesthetics over time, especially in the cervical area, can be considerably diminished with the help of CAD/CAM (Computer Aided Design/ Computer Aided Manufacturing) technology. If the traditional prosthetics does notmore left to say, CAD/CAM technology is currently influencing the entire field of activity in clinical dentistry and dental technology. Material and method: In this article, we present a study carried out during 5 years in which we performed both metal-ceramic rehabilitation works using the classic method and monolithic zirconia using CAD-CAM technology on a number of 15 patients. Oral rehabilitation was carried out in the frontal area, analyzing the complications arising for the two prosthetic options during the 5 years. Results: The technology complements, or even completely replaces, the conventional processes of confectioning prosthetic restorations. Moreover, the modern CAD/CAM systems allow the creation of high-quality prosthetic parts that can be individually adapted to the clinical situation and the financial possibilities of the patients. During the 5 years, complications appeared in the metal-ceramic restorations, primarily represented by unaesthetic gingival retraction and the highlighting of the supporting metal. The realization of very precise prosthetic restorations respecting the technical characteristics of the materials depends on the technological flow, on the coordination of the technological stages in the process of making them, so that the CAD/CAM technology becomes superior to the conventional manufacturing stages. Conclusions: It is known the fact that each manual stage is connected to an error potential more or less important. The elimination of these stages prone to errors, such as the casting of the prosthetic works, will be a great step in the elevation of the precision degree of the prosthetic pieces. Merely the ones said untill now justify the use of the CAD/CAM technologies in the daily activity in the dental technique laboratories. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was (i) to evaluate the clinical performance of reduced‐diameter implants placed in the molar area and (ii) to test whether monolithic zirconia implant‐supported crowns lead to similar clinical outcomes compared to porcelain‐fused‐to‐metal crowns. Materials and Methods: A total of 76 patients needing a single implant crown in the posterior region were recruited. All patients received a titanium–zirconium reduced‐diameter implant (Straumann Roxolid, Tissue Level, Standard Plus, diameter 3.3 mm, regular neck) randomly allocated to receive either a (1) monolithic zirconia crown (test) or (2) porcelain‐fused‐to‐metal crown (control). Implant survival, prosthetic outcomes, and patient‐reported outcomes were assessed at crown delivery and after 3 years of follow‐up. Marginal bone levels (MBL) as well as clinical parameters including probing depth (PD), bleeding on probing (BOP), and plaque levels (PCR) were also recorded. Results: A total of 59 patients were available at the 3‐year follow‐up; 32 patients with a monolithic zirconia crown (TEST) and 27 patients with a porcelain‐fused‐to‐metal crown (CONTROL). 14 implants (11 implant fractures/3 aseptic losses) were lost leading to an estimated implant survival rate of 80% ± 5.1% (95% CI 70.8%–90.8%). Prosthetic complications were limited to the control group and involved minor chippings. Conclusions: This type of reduced‐diameter implant to support single implant molar crowns in the molar area cannot be recommended. Monolithic zirconia crowns appear to be a viable option in the posterior region showing similar prosthetic outcomes to porcelain‐fused‐to‐metal crowns. [ABSTRACT FROM AUTHOR]

The usage of monolithic zirconia has been increasing in daily practice in dentistry for the last 20 years. Monolithic zirconia is mainly used for posterior sector rehabilitation, as it lacks optical properties and has good technical properties; it does not chip and reduces antagonist wear compared to metal–ceramic prostheses. However, monolithic zirconia may present some issues, mainly low-temperature degradation (LTD), also known as "aging", which must be considered and investigated in clinical studies with prolonged follow-up periods. The aim of this study was the aesthetic and functional evaluation of single monolithic zirconia crowns that were screwed onto implants for posterior dental rehabilitation using USPHS parameters and a long follow-up period of 7 years. The results showed that the USPHS scoring reduces year by year, passing from 100% excellence between the first and fourth years of observation, to 88% excellence and 12% success in the seventh year. Screw abutment loosening was the only technical adversity reported; no implant failure, crown fracture, or irreparable damage were additionally registered. Considering the emerging results and comparing them with the data available in the literature, the authors suggest that monolithic zirconia crowns could be considered as a valid alternative to classic metal–ceramic rehabilitations for the rehabilitation of posterior sectors. [ABSTRACT FROM AUTHOR]

Copyright of Fogorvosi Szemle is the property of Hungarian Dental Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fogorvosi Szemle is the property of Hungarian Dental Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background This study aimed to investigate different surface treatments thought to increase the bond strength between zirconia ceramic and adhesive resin cement. Methods The samples were prepared in 15 × 10 × 2 mm dimensions by cutting off monolithic zirconia ceramic blocks (Incoris TZI; Sirona, Germany). Surface roughness measurements were made with a profilometer, the average surface roughness (Ra1) was recorded, and five different surface treatments were applied. Group 1: Control group. No surface treatment was applied. Group 2: Sandblasted with Al2O3 under pressure of 50 μm. Group 3: Sandblasted with 30 μm Al2O3 - SiOx under pressure, then tribochemical silica coating, silane bonding agent, and ceramic primer were applied. Group 4: Samples were etched in a hot acid solution containing methanol, HCl, and chloride at 100 °C. Group 5: Samples were coated in a solution containing Grade C Aluminum Nitrite at 75 °C for 15 Sects. 12,000 thermal aging was carried out to all samples. Then, samples were bonded to a composite surface (Filtek Z250) with two different types of adhesive cement (Panavia F 2.0, Rely X U200) (n = 10). A load was applied to the samples attached to the Universal Test Device for the SBS, and the SBS was recorded. The surface roughness measurements of all samples were made again, and the average surface roughness Ra2 was recorded. The data was analyzed with a two-way ANOVA test. Bonferroni correction was used for multiple comparisons of the groups. p = 0.005 was accepted as the statistically significant value. Results There was no statistically significant difference between the groups in the Ra1 measurements (p = 0.031). There was a statistically significant difference between the Ra2 values of Groups 4 and 5 and the Ra2 values of Groups 1,2 and 3 in the Ra2 measurements (p 0.005). Also, there was no statistically significant difference in the SBS values of all groups for the two different cements tested (p > 0.005). Conclusions None of the surface treatments applied to monolithic zirconia ceramic samples increased the SBS between ceramic and adhesive resin cement.

Abstract Background Since their introduction, there has been limited research regarding the mechanical properties of novel strength-gradient monolithic zirconia. In addition to that, studies evaluating the effect of different core-build materials on the strength of indirect restorations are scarce. Therefore, the aim of this study was to investigate the effect of using different core build-up materials on biaxial flexural strength of a new monolithic multilayered zirconia material. Methods Forty zirconia discs were fabricated from IPS e.max ZirCAD Prime (Ivoclar Vivadent AG, Schaan, Liechtenstein) and divided into 2 groups (n = 20). Forty composite discs were prepared from Tetric N-Ceram (Ivoclar Vivadent AG, Schaan, Liechtenstein) and MultiCore Flow (Ivoclar Vivadent AG, Schaan, Liechtenstein). The zirconia discs were adhesively cemented to the 2 types of composite forming 2 groups (Zirconia-Tetric N-Ceram and Zirconia-MultiCore Flow). Biaxial flexural strength was determined using a piston-on-3-ball test. The data were statistically analyzed with an independent t-test for significant differences (p = 0.05). Results Tetric N-Ceram had significantly higher strength than MultiCore Flow (p

The usage of monolithic zirconia has been increasing in daily practice in dentistry for the last 20 years. Monolithic zirconia is mainly used for posterior sector rehabilitation, as it lacks optical properties and has good technical properties; it does not chip and reduces antagonist wear compared to metal–ceramic prostheses. However, monolithic zirconia may present some issues, mainly low-temperature degradation (LTD), also known as “aging”, which must be considered and investigated in clinical studies with prolonged follow-up periods. The aim of this study was the aesthetic and functional evaluation of single monolithic zirconia crowns that were screwed onto implants for posterior dental rehabilitation using USPHS parameters and a long follow-up period of 7 years. The results showed that the USPHS scoring reduces year by year, passing from 100% excellence between the first and fourth years of observation, to 88% excellence and 12% success in the seventh year. Screw abutment loosening was the only technical adversity reported; no implant failure, crown fracture, or irreparable damage were additionally registered. Considering the emerging results and comparing them with the data available in the literature, the authors suggest that monolithic zirconia crowns could be considered as a valid alternative to classic metal–ceramic rehabilitations for the rehabilitation of posterior sectors.

Abstract Objectives This study aimed to evaluate the maximum bite force (MBF) and satisfaction of patients restored with implants, combined tooth‐implants, and teeth‐supported monolithic zirconia fixed dental prostheses (FDPs). Materials and Methods Thirty partially edentulous patients in need of three units of FDPs in their mandibular posterior region were divided into three equal groups (n = 10) as follows: Group‐1 patients received two implants for each at the second premolar and second molar regions, Group‐2 patients received one implant for each at the second molar region, and Group‐3 patients with missing lower first molar. All the restorations were constructed from monolithic zirconia. Patients were evaluated 1 week after placement of restorations (baseline) and then after 6, 12, and 24‐month intervals for MBF using force transducer occlusal force meter and satisfaction (function, esthetic, and overall satisfaction) using a visual analog scale. Results The mean MBF for Group 1 was higher than Group 2 (p = .044) but not that of Group 3 (p = .923). Additionally, Group 3 displayed a higher MBF than Group 2, although this difference was not statistically significant (p = .096). Concerning patient satisfaction, all study groups reported high levels of satisfaction across all satisfaction elements, and no significant differences were observed between the groups. Conclusion Within the limitations of this study, it can be concluded that Group 1 gives comparable anticipated treatment outcomes as Group 3 concerning biting force and patient satisfaction. However, Group 2 gives comparable satisfaction results with biting force value within the normal range; thus, it might be used as a treatment option in a specific situation.

Increasing demand for adult orthodontic treatment using clear aligners has highlighted challenges in bonding clear aligner attachments to various restorations. Specifically, the bond strength of clear aligner attachments to glazed monolithic zirconia has not been extensively studied. This study aims to compare the shear bond strength (SBS) and mode of failure (MOF) of conventional bonding methods versus Superbond C&B (4-META/MMA-TBB resin cement) for clear aligner attachments on glazed monolithic zirconia. Fifty sintered and glazed zirconia samples were divided into five groups and attached with clear aligner attachments: Si (silane), B (bonding agent), SiB (bonding agent and silane), SU (Superbond C&B), and SiSU (silane and Superbond C&B). SBS and MOF of these samples were analyzed. Results indicated a significant difference in bond strength among the groups. SiSU exhibited the highest bond strength, followed by SU, while B had the lowest bond strength. SEM analysis revealed that SiSU and SU predominantly exhibited mixed failure, indicating high bond strength without affecting the glazed layers of the zirconia. In contrast, B exhibited only adhesive failure at the interface, resulting in insufficient bond strength for effective orthodontic treatment. In conclusion, using 4-META/MMA-TBB resin cement provides high bond strength for clear aligner attachments on glazed zirconia with minimal material damage during debonding.

Background: Since their introduction, there has been limited research regarding the mechanical properties of novel strength-gradient monolithic zirconia. In addition to that, studies evaluating the effect of different core-build materials on the strength of indirect restorations are scarce. Therefore, the aim of this study was to investigate the effect of using different core build-up materials on biaxial flexural strength of a new monolithic multilayered zirconia material. Methods: Forty zirconia discs were fabricated from IPS e.max ZirCAD Prime (Ivoclar Vivadent AG, Schaan, Liechtenstein) and divided into 2 groups (n = 20). Forty composite discs were prepared from Tetric N-Ceram (Ivoclar Vivadent AG, Schaan, Liechtenstein) and MultiCore Flow (Ivoclar Vivadent AG, Schaan, Liechtenstein). The zirconia discs were adhesively cemented to the 2 types of composite forming 2 groups (Zirconia-Tetric N-Ceram and Zirconia-MultiCore Flow). Biaxial flexural strength was determined using a piston-on-3-ball test. The data were statistically analyzed with an independent t-test for significant differences (p = 0.05). Results: Tetric N-Ceram had significantly higher strength than MultiCore Flow (p < 0.001) but no statistically significant differences were found in strength values between Zirconia-Tetric N-Ceram and Zirconia-MultiCore Flow bilayered samples (p = 0.27). Conclusions: It was concluded that although the tested composite core materials significantly differ in their biaxial flexural strength values, they had no influence on the biaxial flexural strength of the overlying zirconia. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate different surface treatments thought to increase the bond strength between zirconia ceramic and adhesive resin cement. Methods: The samples were prepared in 15 × 10 × 2 mm dimensions by cutting off monolithic zirconia ceramic blocks (Incoris TZI; Sirona, Germany). Surface roughness measurements were made with a profilometer, the average surface roughness (Ra1) was recorded, and five different surface treatments were applied. Group 1: Control group. No surface treatment was applied. Group 2: Sandblasted with Al2O3 under pressure of 50 μm. Group 3: Sandblasted with 30 μm Al2O3 - SiOx under pressure, then tribochemical silica coating, silane bonding agent, and ceramic primer were applied. Group 4: Samples were etched in a hot acid solution containing methanol, HCl, and chloride at 100 °C. Group 5: Samples were coated in a solution containing Grade C Aluminum Nitrite at 75 °C for 15 Sects. 12,000 thermal aging was carried out to all samples. Then, samples were bonded to a composite surface (Filtek Z250) with two different types of adhesive cement (Panavia F 2.0, Rely X U200) (n = 10). A load was applied to the samples attached to the Universal Test Device for the SBS, and the SBS was recorded. The surface roughness measurements of all samples were made again, and the average surface roughness Ra2 was recorded. The data was analyzed with a two-way ANOVA test. Bonferroni correction was used for multiple comparisons of the groups. p = 0.005 was accepted as the statistically significant value. Results: There was no statistically significant difference between the groups in the Ra1 measurements (p = 0.031). There was a statistically significant difference between the Ra2 values of Groups 4 and 5 and the Ra2 values of Groups 1,2 and 3 in the Ra2 measurements (p < 0.001). There was no statistically significant difference between the SBS values of the groups (p > 0.005). Also, there was no statistically significant difference in the SBS values of all groups for the two different cements tested (p > 0.005). Conclusions: None of the surface treatments applied to monolithic zirconia ceramic samples increased the SBS between ceramic and adhesive resin cement. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to evaluate the bond strengths of two different composite types used in the production of clear aligner attachments on monolithic zirconia with three different surface roughening processes. Materials and Methods: Packable composite Filtek Z250 was used in one group (PC‐G) and flowable composite Filtek Supreme Ultra Flowable was used in the other group (FC‐G). PC‐G and FC‐G groups were also divided into three subgroups as diamond bur+silane (Group 1), 50 μm aluminium oxide (Al2O3) sandblasting+silane (Group 2) and 110 μm Al2O3 sandblasting+silane (Group 3). Scanning electron microscopy (SEM) analysis was performed. Clear aligner attachments were bonded to the monolithic zirconia specimens. Shear bond strength (SBS) values were measured. Statistical analysis was performed using two‐way ANOVA and post‐hoc Tukey's tests (P <.05). Results: The highest SBS value was found in PC‐G sandblasted with 110 μm Al2O3 (P ≤.001). The etching method with 110 μm sandblasting showed high SBS values in both composite types. The lowest SBS value gave FC‐G in diamond bur roughening (P ≤.001). Conclusions: For the bonding of clear aligner attachments on monolithic zirconia, roughening with 110 μm particle size sandblasting and the choice of packable composite could be recommended in terms of retention. [ABSTRACT FROM AUTHOR]

Purpose: To compare the failure rates and the prevalence of technical complications between full-coverage tooth-supported monolithic zirconia (MZ) and porcelain-veneered zirconia (PVZ) fixed dental prosthesis, based on a systematic literature review. Methods: An electronic search was performed in three databases, supplemented by hand searching. Several statistical methods were used. Results: Seventy-four publications reported 6370 restorations (4264 PVZ; 2106 MZ; 8200 abutment teeth; 3549 patients), followed up until 152 months. A total of 216 prostheses failed, and survival was statistically significant different between groups. PVZ had higher occurrence of complications than MZ; the difference was especially greater for either minor or major chipping. The difference in prevalence of either minor or major chipping was statistically significant for PVZ prostheses between cementation with glass ionomer and adhesive resin cement (higher), adhesive resin and resin-modified glass ionomer cement (RMGIC, higher), and between RMGIC (higher) and glass ionomer cement. For MZ the difference was significant only for minor chipping between RMGIC (higher) and adhesive resin cement. Abutment teeth to PVZ prostheses more often lost vitality. Decementation was not observed with RMGIC. Air abrasion did not seem to clinically decrease the decementation risk. The 5-year difference in the occurrence of minor or major chipping between MZ and PVZ prostheses was statistically significant, but nor for catastrophic fracture. Conclusion: Tooth-supported PVZ prostheses present higher failure and complication rates than MZ prosthesis. The difference in complications is striking when it comes to chipping. Clinical relevance: Awareness of the outcome differences between different types of zirconia prostheses is important for clinical practice. [ABSTRACT FROM AUTHOR]

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Objectives: This study aimed to evaluate the maximum bite force (MBF) and satisfaction of patients restored with implants, combined tooth‐implants, and teeth‐supported monolithic zirconia fixed dental prostheses (FDPs). Materials and Methods: Thirty partially edentulous patients in need of three units of FDPs in their mandibular posterior region were divided into three equal groups (n = 10) as follows: Group‐1 patients received two implants for each at the second premolar and second molar regions, Group‐2 patients received one implant for each at the second molar region, and Group‐3 patients with missing lower first molar. All the restorations were constructed from monolithic zirconia. Patients were evaluated 1 week after placement of restorations (baseline) and then after 6, 12, and 24‐month intervals for MBF using force transducer occlusal force meter and satisfaction (function, esthetic, and overall satisfaction) using a visual analog scale. Results: The mean MBF for Group 1 was higher than Group 2 (p =.044) but not that of Group 3 (p =.923). Additionally, Group 3 displayed a higher MBF than Group 2, although this difference was not statistically significant (p =.096). Concerning patient satisfaction, all study groups reported high levels of satisfaction across all satisfaction elements, and no significant differences were observed between the groups. Conclusion: Within the limitations of this study, it can be concluded that Group 1 gives comparable anticipated treatment outcomes as Group 3 concerning biting force and patient satisfaction. However, Group 2 gives comparable satisfaction results with biting force value within the normal range; thus, it might be used as a treatment option in a specific situation. [ABSTRACT FROM AUTHOR]

To evaluate the fracture strength and the failure mode of endodontically treated molars restored with monolithic lithium disilicate and zirconia endocrowns and overlays. A total of 48 extracted mandibular molars were endodontically treated, decoronated 2 mm above the cementoenamel junction and divided into four 12-specimen groups. Group ELD: lithium disilicate endocrowns. Group EZ: monolithic zirconia endocrowns. Group OLD: lithium disilicate overlays. Group OZ: monolithic zirconia overlays. Overlays did not extend in the pulp chamber and endocrowns extended in the pulp chamber 2 mm. After adhesive bonding of the restorations, the specimens were subjected to thermocycling (×5000 cycles) and then to fracture resistance testing at lateral static loading (1 mm/min) at a universal testing machine. The failure mode of the specimens was qualitatively evaluated. Differences in means were compared using with t-tests for independent samples or Mann–Whitney test (p < 0.05). Weibull distribution analysis was also performed. Group ELD showed significantly higher fracture strength than all other groups (p = 0.001), and the highest Weibull modulus. Conclusions: Lithium disilicate endocrowns exhibit higher fracture strength and are more reliable compared to the other types of restorations examined. Endocrowns had more catastrophic failures compared to overlays. [ABSTRACT FROM AUTHOR]

Objectives: To assess the probability of survival of crowns made with a 3Y-TZP, a 5Y-TZP, and a lithium disilicate. Materials and methods: CAD-CAM premolar crowns with occlusal thicknesses of 1.0 mm or 1.5 mm and cemented on a metal dye. Step-stress accelerated life testing (SSALT) was performed to access the use level probability Weibull curves and reliability were calculated for the completion of a mission of 100,000 cycles at 300 to 1200 N. Results: All ceramics showed a high probability of survival (87–99%) at 300 N, irrespective of thickness. 3Y-TZP shows no significant decrease in the probability of survival up to 1200 N (83–96%). Lithium disilicate presented lower reliability than zirconia under the 600 N mission. 5Y-TZP showed lower reliability than 3Y-TZP at 1200 N. There was no significant difference in the Weibull modulus (3.23–7.12). 3Y-TZP had the highest characteristic strength (2483–2972 N), followed by 5Y-TZP (1512–1547 N) and lithium disilicate (971–1154 N). Conclusion: Zirconia ceramics have a high probability of survival (up to 900 N-load), while lithium disilicate survives up to 300 N load only, irrespective of the thickness (1.0 mm or 1.5 mm). Clinical relevance: The probability of survival of posterior crowns made with zirconia ceramics resists extreme loads while glass ceramics resist normal chewing loads. In addition, crowns with thinner occlusal face showed sufficient mechanical behavior. [ABSTRACT FROM AUTHOR]