Cadiax Compact 2 and MODJAW comparative analysis of condylar inclination: Innovative digital approaches in dentistry.

STATEMENT OF PROBLEM: Artificial intelligence has been used to enhance the digitalized workflow, especially when undergoing complex oral rehabilitations. However, the reliability of real-time jaw motion registration devices is unclear, and no standard measurement method of the sagittal condylar inclination (SCI) and Bennett angle (BA) has been established. PURPOSE: The purpose of this clinical study was to compare and evaluate the reliability of the SCI and BA values recorded by using 2 different digital devices. MATERIAL AND METHODS: A total of 17 participants, aged between 20 and 30 years (10 women and 7 men) were included in the study. For each participant, the Cadiax Compact 2 and MODJAW tracking devices were used to measure the SCI and BA values at 3 mm and 5 mm of condylar displacement during 3 separate recording sessions. The intraclass correlation coefficient (ICC) was used to assess the reliability of the recordings. Comparisons between the devices were performed with the Wilcoxson rank-sum test (α=.05). The Bland-Altman plot was used to evaluate the quantitative agreement between the 2 devices. RESULTS: All ICC intrarater reliability values for Cadiax and MODJAW were higher than 0.90. Both at 3 and 5 mm, the SCI measurements were higher for MODJAW registrations than for those recorded by Cadiax. The Bland-Altman plot showed that the SCI values were higher for MODJAW than for Cadiax by 5.9 (95% CI 3.9 to 8.2) and that the BA differences between the MODJAW and the Cadiax were not consistent with the measured value. CONCLUSIONS: Excellent reliability was found with the MODJAW and Cadiax recordings. The SCI and BA values for MODJAW measurements were higher at 3 mm and 5 mm than those acquired with Cadiax. MODJAW showed higher values than Cadiax, and the discrepancies were more pronounced for 3 mm than for 5 mm of condylar displacement, highlighting the need for precision in measurements at lower ranges of motion.

Zirconia-Reinforced Lithium Silicate Ceramic in Digital Dentistry: A Comprehensive Literature Review of Our Current Understanding.

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.

Influence of manufacturing technique on the color of zirconia restorations: Monolithic versus layered crowns.

OBJECTIVES: The study aimed to compare the color of monolithic and layered zirconia crowns fabricated using different brands in the cervical, middle, and incisal areas. MATERIALS AND METHODS: A total of 45 crowns were fabricated from three brands (Katana, Nacera, Cercon) using three methods (monolithic = ML (n=5), cut-back + enamel = BL (n=5), cut-back + dentin + enamel = TL (n=5)). CIE L*, a* b*, C*, h° color coordinates were recorded with a dental spectrophotometer in cervical, middle, and incisal areas. Color differences between manufacturing techniques, tooth areas, and brands were calculated using the CIEDE2000(1:1:1) formula, and the values were compared to the perceptibility (PT00 ) and acceptability thresholds (AT00 ). Comparisons between color coordinates were analyzed statistically (Kruskal-Wallis and Mann-Whitney U tests, p < 0.001). RESULTS: Significant differences were found between CIE L*, a*, b*, C*, h° coordinates of the zirconia crowns (p < 0.001), generally. The lowest color differences were obtained between BL and TL crowns in cervical and middle areas. Color differences between cervical and middle areas were mostly below PT00 . An acceptable color difference was found between Katana and Cercon crowns. CONCLUSIONS: The manufacturing technique and the brand influenced the color of zirconia crowns. Also, the color of the crowns varied from cervical to incisal. CLINICAL SIGNIFICANCE: Reproducing the optical properties of teeth with ceramic crowns might be challenging, given the differences in the internal configuration of the enamel and dentine, as well as their complex behavior when interacting with light. When deciding whether to fabricate a monolithic crown in translucent zirconia or improve its appearance by layering with more translucent glass-ceramic, the clinicians and dental technicians must be aware of these procedures' effect on the final color of the restorations.

Effect of glazing on translucency, color, and surface roughness of monolithic zirconia materials.

OBJECTIVES: To assess the effect of material, thickness and glazing upon the color, translucency, and roughness of monolithic zirconia. MATERIALS AND METHODS: Sixty discs (0.8, 1.5, and 2 mm thickness) were fabricated from A1 translucent zirconia (IPS e.max ZirCAD/MT, Katana/HT, Vita YZ/HT, Cercon/HT) and glazed. Roughness (Ra) was assessed with a profilometer and color coordinates were measured with a spectrophotometer on a black, white, and tooth-shaded background before and after glazing. Relative translucency parameter (RTP), color differences (CIEDE2000) and differences in translucencies between materials, before and after glazing were calculated. RTP, Ra, color differences were statistically analyzed using ANOVA. Any significant interaction between factors was further analyzed using Tukey's HSD. RESULTS: RTP values were significantly different between materials (P < .001) and thicknesses (P < .001), with the interaction effect between material type and thickness, also significant (P < .001). However, glazing did not have a significant effect on RTP values (P = .782). Color differences resulted after glazing were significantly different between materials (P < .001), and thicknesses (P < .001) with the interaction effect also significant (P < .001). Glazing influenced roughness, Ra decreasing for all materials (P < .001). CONCLUSIONS: As a result of glazing, only color changes were statistically significant. Translucency varied among brands of precolored monolithic zirconia; the differences increased for greater thicknesses. CLINICAL SIGNIFICANCE: Glazing is an important step in the technological process of ceramic restorations; however, it can influence the final optical appearance of the restoration as color changes could be expected after the application of the glaze.

Endocrowns - a literature review.

Introduction: The opportunity of using Endocrown-type restorations in the current prosthetic dentistry practice as an alternative to other, well-established methods of corono-radicular restorations and the evolving palette of adhesive materials has made these restorations more popular in the last few years. Objective: The purpose is to review the available literature about Endocrown restorations regarding mechanical properties - fracture strength and resistance, survival rate, the preparation design - marginal and internal adaptation, and esthetics. Method: The search was carried out on four databases: PubMed, Scopus (ScienceDirect), Web of Science, and Scielo using the following terms: "endocrowns", "endodontic crown", and" no buildup crown". Initially, a total of 163 articles published between 2015 and May 2021 were selected. After the duplicates, papers presented only as abstracts, articles in any other languages except English, and review articles were eliminated; a total of 72 articles remained to be considered for this review.After assessing the 72 considered articles, 37 were chosen as fit for this review. The reasons for the elimination of the other 35 articles were: their main focus was other than endocrowns, e.g., direct restorations, indirect restorations of vital teeth; case reports; study protocols. Results: From the 37 articles selected, 34 were focused on mechanical properties, including the influence of the preparation design, and three on survival rate, of which one also had a point of view regarding esthetics. Conclusions: The literature included in this review shows that endocrowns perform similarly or even better in some cases than other coronal restorations. However, this statement must be interpreted cautiously, given that most articles were in vitro or finite element analysis studies. Given the high degree of conflicting results found in the articles included in this review, the authors consider as reasonable to conclude that further studies are needed to confirm the feasibility of endocrowns and the best choice of material.

Survival Rates of Glass versus Hybrid Ceramics in Partial Prosthetic Restorations: A Scoping Review with Emphasis on Adhesive Protocols.

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.

Translucent Zirconia in Fixed Prosthodontics-An Integrative Overview.

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.

SEM Evaluation of Marginal Adaptation E-Max Crowns Manufactured by Printing-Pressed and Milling.

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.

Masking Ability of Monolithic and Layered Zirconia Crowns on Discolored Substrates.

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.

Color and masking properties of translucent monolithic zirconia before and after glazing.

Purpose 1. to assess the ability of four brands of translucent monolithic zirconia with different thicknesses to mask discolored substrates; 2. to assess the influence of glazing upon their color coordinates and masking properties.Methods Sixty samples of shade A1 (0.8, 1.5, and 2.0 mm thickness) from: ZirCAD/MT, Katana/HT, Vita YZ/HT, Cercon/HT were fabricated and glazed using a standardized laboratory procedure. CIE L*a*b* parameters were recorded on composite substrates, (IPS Natural Die Material Kit) (ND1=reference; ND2, ND3, ND4, ND5=test backgrounds), before and after glazing. The color changes of zirconia samples induced by glazing were analyzed. Masking properties was calculated as the color difference between CIE L*a*b* parameters of the samples placed on reference and test substrates with CIEDE2000(1:1:1) formula. The effect of material, thickness, substrate, and glazing on the color of monolithic zirconia was analyzed with ANOVA test and the multiple comparisons were analyzed with Tukey HSD tests (α=0.05).Results After glazing, lightness L* significantly increased, while chromatic coordinates a* and b* decreased (p<0.05). Significant differences in the masking properties of the four materials (p<0.001) were found, with IPS e.max ZirCAD/MT having the lowest masking effect (p<0.001). Thickness, substrate and glazing had a significant effect on the color masking properties of monolithic zirconia (p<0.001).Conclusions Masking properties of translucent zirconia were significantly influenced by the materials, the thickness and the color of the substrate; moreover, glazing improved the masking ability for all zirconia samples.

Temporomandibular dysfunction diagnosis by means of computerized axiography.

BACKGROUND AND AIMS: The objective of this study was to evaluate the accuracy of the CADIAX Compact 2 axiograph in confirming the presumptive clinical diagnosis of temporomandibular dysfunction, established according to the muscular-articular clinical examination. METHODS: A retrospective analytical study was carried out on 50 patients, aged between 21 and 62 years, 31 women and 19 men. A clinical diagnosis was established after masticatory muscles, temporomandibular joints and mandibular border limit movements were assessed. During the same day a computerized axiography (Cadiax Compact 2, Gamma, Vienna, Austria) was performed in order to confirm the diagnosis. RESULTS: The study had a sensitivity of 100%, which means that the CADIAX device detected all clinically positive patients. On the other hand, the specificity of the study was 74%, representing the percentage of patients negatively diagnosed by CADIAX device out of the total number of patients clinically diagnosed as negative. The 88% accuracy shows the proportion in which the CADIAX device provides a diagnosis equal to the clinical one. CONCLUSIONS: Of all the methods for investigating temporomandibular joint dysfunction, axiography is less invasive, does not irradiate the patient, it is relatively easy to use and it offers functional information about the TMJ function.

Clinical occlusion analysis versus semi-adjustable articulator and virtual articulator occlusion analysis.

BACKGROUND AND AIMS: Identifying the optimal method for occlusion analysis by comparing examination sensitivity of the static and dynamic occlusion using three systems: clinical occlusion analysis, semi-adjustable articulator and virtual articulator (3Shape, Denmark) occlusion analysis. METHODS: The occlusion analysis of sixteen patients was performed using the three systems. In order to analyze the number of concordant and discordant points and trajectories, the clinical method was compared to the semi-adjustable articulator and to the computerized method. RESULTS: The greatest correspondence was obtained by comparing the clinical and the articulator methods, having a success rate of 85.25%, versus the clinical and the computerized method with a success rate of 73.25%. The propulsion registered the highest discrepancies: 35% in case of the semi-adjustable articulator comparison and 62% in case of the virtual articulator comparison. CONCLUSIONS: The semi-adjustable articulator was superior in static and dynamic occlusion analysis compared to the virtual articulator. The analysis of the dynamic occlusion is the most problematic due to its dependency on the individual anatomy of the glenoid fossa which cannot be exactly reproduced by any articulator.