Zirconia-reinforced lithium silicate (ZLS) ceramic is a new innovative dental material with unique a chemical composition that is designed to combine harmoniously with the appropriate optical properties of lithium disilicate and the enhanced mechanical strength of zirconia. A thorough understanding of ZLS materials is essential for both clinicians and dental technicians. At present, the mechanical behavior and optical properties of the ZLS ceramic system have not been extensively researched, and there is still a lack of consensus regarding the fabrication process and clinical behavior of ZLS all-ceramic restorations. The aim of the present study was to present a selection of comprehensive information concerning zirconia-reinforced lithium silicate ceramics and their optical and mechanical properties, as well as to assess data regarding cementation procedures and clinical outcomes for ZLS all-ceramic restorations. Three electronic databases (PubMed, Web of Science, and the Cochrane Library) were used for the research by two independent reviewers. The search was limited to articles published in the English language, as well as clinical and in vitro studies of color and studies on mechanical behavior and the cementation procedures of ZLS restorations. The exclusion criteria comprised abstracts, questionnaire-based studies, case reports, literature reviews, and studies that were not available in English. Zirconia-reinforced lithium-silicate-based ceramic presents a unique and complex microstructure that increases mechanical resistance but decreases aesthetic appearance, especially its translucency, due to tetragonal zirconia content. A material’s thickness, the color of the underlying tooth structure, and the resin cement shade are important factors that influence the final shade and aesthetic appearance of ZLS restorations. Mechanical properties, which are defined by the fracture toughness, flexural strength, elastic modulus, and hardness of ZLS ceramic are higher compared to feldspathic, lithium disilicate, and hybrid ceramics, as well as resin nanoceramics; however, they are lower than translucent or high-translucency zirconia. Acid etching, sandblasting, and laser etching represent the most used methods to prepare the ZLS restoration surfaces for proper bonding procedures.

Over the past two decades, dental ceramics have experienced rapid advances in science and technology, becoming the fastest-growing field of dental materials. This review emphasizes the significant impact of translucent zirconia in fixed prosthodontics, merging aesthetics with strength, and highlights its versatility from single crowns to complex bridgework facilitated by digital manufacturing advancements. The unique light-conducting properties of translucent zirconia offer a natural dental appearance, though with considerations regarding strength trade-offs compared to its traditional, opaque counterpart. The analysis extends to the mechanical attributes of the material, noting its commendable fracture resistance and durability, even under simulated physiological conditions. Various zirconia types (3Y-TZP, 4Y-TZP, 5Y-TZP) display a range of strengths influenced by factors like yttria content and manufacturing processes. The study also explores adhesive strategies, underlining the importance of surface treatments and modern adhesives in achieving long-lasting bonds. In the realm of implant-supported restorations, translucent zirconia stands out for its precision, reliability, and aesthetic adaptability, proving suitable for comprehensive dental restorations. Despite its established benefits, the review calls for ongoing research to further refine the material’s properties and adhesive protocols and to solidify its applicability through long-term clinical evaluations, ensuring its sustainable future in dental restorative applications.

There is scarce information on the colorimetric behavior of monolithic and layered zirconia crowns in combination with various abutment colors. This study evaluated the masking ability on discolored substrates of monolithic and layered zirconia crowns. Anterior crowns were fabricated using 3Y-TZP zirconia and layering ceramic and divided into three groups: monolithic (ML), bi-layer (BL), and tri-layer (TL). The crowns were placed over eleven substrates (ND1-ND9, zirconia, metal), and CIE L*, a*, b*, C*, and h° color coordinates were measured in the cervical, middle, and incisal areas with a spectrophotometer. Masking ability was calculated using the color difference formula, and values were interpreted according to the perceptibility and acceptability thresholds. Data were analyzed statistically (α = 0.001). The L* coordinate was not significantly different between BL and TL crowns, regardless of the measurement area or substrate (p ≥ 0.001). In the middle area, the L* coordinate of the ML group was statistically different from the BL and TL groups only for zirconia and metal substrates, while in the incisal area, only for ND7 and metal substrates. The a* coordinate was significantly different between the ML and layered crowns for all measurement areas and substrates (except zirconia). The b* and C* coordinates differed significantly between the groups only in the cervical area (p < 0.001). The ML crown had better masking ability than the BL and TL crowns. However, the color differences for ML crowns were below the acceptability threshold for ND2, ND3, and ND7 substrates in the cervical and middle areas and below perceptibility threshold only for the incisal area. The lowest masking ability of the crowns was found for ND9 and metal substrates in all measurement areas.

Dental crown marginal adaptation is a matter of the success of dental restoration treatment. Nowadays, there are many technological ways for crown manufacturing, such as tridimensional printing of an exactly desired shape through CAD-assisted systems and the appropriate shape milling of a predesigned bulk crown. Both methods are developed for patient benefits. The current research aims to investigate the marginal adaptation of E-Max crowns manufactured by printing-pressed and milling methods. The in vitro cementation procedures were effectuated on healthy teeth extracted for orthodontic purposes according to the standard procedures and the marginal adaptation was investigated with SEM microscopy. The restoration overview was inspected at a magnification of 100× and the microstructural details at 400×. The integrity of marginal adaptation was properly inspected in identical samples on segments of 2 mm from each buccal, palatal, distal and mesial side. The obtained results reveal a good marginal adaptation for all samples, with some particularities. The statistical analysis shows that the best values of the marginal adaptation were obtained for vestibular/buccal and palatal sides of the teeth being situated around 90–95%, while the values obtained for distal and mesial sides are slightly lower such as 80–90%. Furthermore, it was observed that the milled crowns presents better marginal adaptations than the printed-pressed ones, sustained by the statistical p < 0.05. This indicates that the milling process allows a better fit of the crown to the tooth surface and preserves the integrity of the bonding cement layer.

As dental practices and methodologies evolve, the emergence of novel materials adds complexity to clinical choices. While glass ceramics, particularly those based on lithium disilicate and leucite-reinforced variants, have been extensively researched and are well regarded for their attributes, hybrid ceramics remain relatively recent area of research that is less investigated. This review aims to evaluate the durability of glass and hybrid ceramics while assessing the role of various adhesive techniques on restoration longevity. Using a comprehensive search of PubMed and EMBASE, 84 articles from the past decade were found. Only eleven met the set criteria for analysis. The results underscore the urgent need for the extended monitoring of partial prosthetic restorations. The existing literature has significant gaps, hindering the attainment of dependable insights about these materials’ long-term performance. For a clearer understanding of how different ceramic systems affect restoration survival rates, rigorous research involving more participants and uniform outcome documentation is vital.