Artificial neural networks development in prosthodontics - a systematic mapping review.

OBJECTIVES: This study aimed to systematically categorize the available literature and offer a comprehensive overview of artificial neural network (ANN) prediction models in prosthodontics. Specifically, the present research introduces a systematic analysis of ANN aims, data, architectures, evaluation metrics, and limitations in prosthodontics. DATA: The review included articles published until June 2024. The search terms included "prosthodontics" (and related MeSH terms), "neural networks", and "deep learning". Out of 597 identified articles, 70 reports remained after deduplication and screening (2007-2024). Of these, 33% were from 2023. Implant prosthodontics was the focus in approximately 29% of reports, and non-implant prosthodontics in 71%. SOURCES: Data were collected through electronic searches of PubMed MedLine, PubMed Central, ScienceDirect, Web of Science, and IEEE Xplore databases, along with manual searches in specific journals. STUDY SELECTION: This study focused on English-language research articles and conference proceedings detailing the development and implementation of ANN prediction models specifically designed for prosthodontics. CONCLUSIONS: This study shows how ANN models are used in implant and non-implant prosthodontics, with various types of data, architectures, and metrics used for their development and evaluation. It also reveals limitations in ANN development, particularly in the data lifecycle. CLINICAL SIGNIFICANCE: This study equips practitioners with insights, guiding them in optimizing clinical protocols through ANN integration and facilitating informed decision-making on commercially available systems. Additionally, it supports regulatory efforts, smoothing the path for AI integration in dentistry. Moreover, it sets a trajectory for future exploration, identifying untapped tools and research avenues, fostering interdisciplinary collaborations, and driving innovation in the field.

Wide Restorative Emergence Angle Increases Marginal Bone Loss and Impairs Integrity of the Junctional Epithelium of the Implant Supracrestal Complex: A Preclinical Study.

AIM: To assess the influence of the emergence angle on marginal bone loss (MBL) and supracrestal soft tissue around dental implants. MATERIALS AND METHODS: In six mongrel dogs, the mandibular premolars and molars were extracted. After 3 months of healing, four dental implants were placed in each hemimandible. The implants were randomly allocated to receive one of four customized healing abutments, each with a different value of the restorative emergence angle: 20°, 40°, 60° or 80°. Intra-oral radiographs were taken after placing the healing abutments and at 6, 9, 16 and 24 weeks of follow-up. Then, micro-CT and undecalcified histology and synchrotron were performed. MBL over time was analysed with generalized estimating equations (GEEs) and adjusted for baseline soft-tissue thickness. RESULTS: From implant placement to 24 weeks, GEE modelling showed that the MBL at mesial and distal sites consistently increased over time, indicating MBL in all groups (p < 0.001). The model indicated that MBL varied significantly across the different restorative angles (angle effect, p < 0.001), with 80° showing the greatest bone loss. Micro-CT, histology and synchrotron confirmed the corresponding trends and showed that wide restorative angles (60° and 80°) impaired the integrity of the junctional epithelium of the supracrestal tissue. CONCLUSIONS: A wide restorative angle increases MBL and impairs the integrity of the junctional epithelium of the implant supracrestal complex.

The Applications of 3D-Printing Technology in Prosthodontics: A Review of the Current Literature.

Prosthodontics has become increasingly popular because of its cosmetic attractiveness. 3D printing has revolutionized prosthodontics, enabling the creation of high-quality dental prostheses. It creates detailed restorations, such as crowns, bridges, implant-supported frameworks, surgical templates, dentures, and orthodontic models. In addition, it saves production time but faces challenges such as elevated expenses and the requirement for innovative materials and technologies. This review gives insights into the uses of 3D printing in prosthodontics, presenting how it has significantly changed clinical practices. This article discusses different materials and techniques. Additionally, it showcases the capacity of 3D printing to improve prosthodontic practice and proposes prospects for future investigation.

Analysis of occlusal clearance of crown preparations in a predoctoral clinical setting.

PURPOSE: This study sought to assess the presence and location of inadequate tooth preparation performed by predoctoral dental students by scanning mounted casts submitted for monolithic zirconia crown fabrication METHODS: An intraoral scanner capable of volumetric measurements of crown preparations was used to analyze 56 crown preparations on mounted stone casts before submission to a lab for crown fabrication. The mounted casts were scanned individually and then a buccal bite was scanned to stitch the models together into virtual occlusion. The distance between the crown preparations and opposing dentition was displayed volumetrically, and the minimum clearance of each preparation was recorded for both the functional and non-functional cusps. Preparations were evaluated for adequate interocclusal clearance and comparisons were made using a Chi-square test with α = 0.05 with respect to tooth location, functional versus nonfunctional cusp, and or single versus multi-unit preparation. RESULTS: Over 47% of mounted casts with crown preparations analyzed for the study exhibited a lack of occlusal clearance in at least one area. Functional cusps were more often under-reduced than non-functional (p < 0.001). No other comparisons were statistically significant. CONCLUSIONS: The present study demonstrates a high percentage of under-reduced crown preparations in a predoctoral clinic and emphasizes the utility of quality control and analysis via digital scanning of crown preparations prior to crown fabrication.

Digital technology implementation in prosthodontics postgraduate programs in Saudi Arabia: a multi-institutional survey of program directors.

OBJECTIVE: To assess the current status of digital technology (DT) implementation in prosthodontics post-graduate (PG) programs in Saudi Arabian dental institutions. METHODOLOGY: A 19-item survey was created using Google forms and the link was emailed to the 29 prosthodontics PG program directors (advanced clinical training and joint program) in Saudi Arabia. The questionnaire contained five Sect. 1) didactic training and DT usage in PG preclinical, clinical and laboratory training, 2) incorporation of DT in PG program, 3) utilization of DT and the types of cases treated by PG students during their course, 4) information on the faculties involved in prosthodontics PG education, and 5) potential challenges encountered and program directors' satisfaction of the PG program. Descriptive statistics was used to present the frequencies and proportions, and Chi square inferential test was used to compare the participants' response based on the type of PG programs (α = 0.05). RESULTS: Only 28 program directors responded to the survey, yielding a 95.5% response rate. Among the program directors, 24 (85.7%) and 4 (14.3%) directors supervised the advanced clinical training and joint programs, respectively. Among the DT, CAD/CAM was the most used technology (50-80%), followed by intra-oral scanning (28-96%). Digital technology implementation was largely limited by lack of resources or equipment (67%), cost (53%) and scarcity of PG teaching staff (46%). A significant difference was observed between the programs regarding the mandatory use of DT for their cases (p = 0.03). CONCLUSIONS: This multi-institutional survey of program directors revealed that DT is continuously implemented in the last few years. Saudi dental institutions must prioritize implementing and utilizing DT in PG training to graduate competent prosthodontists in this fast-paced digital era. While DT is pivotal in dental education, its implementation is limited in many institutions due to resources or equipment, cost, and lack of trained faculty.

Efficacy of Conventional versus Cordless Displacement System on Gingival Retraction for Use with Intra-Oral Scanner: A Clinical Study.

Aim: The present clinical study aimed to assess the efficacy of conventional versus cordless displacement systems on gingival retraction for use with an intra-oral scanner and changes in periodontal indices. Materials and Methods: A total of 20 participants were selected for a split-mouth study (20 sites - Group Sc, 20 sites - Group Es). The outcomes were measured at day 0, day 1, and day 7 of follow-up in terms of Immediate horizontal displacement, Plaque Index, and Bleeding Index. Unpaired and Paired t-test was used as the parametric tests and statistical analysis was performed. Results: A statistically significant change was observed in terms of BI on day 0, but no statistically significant change was observed for either group in terms of IHD and PI. Conclusion: The cordless material caused the least trauma to gingival tissue and was more compatible with intra-oral scanning devices.

The Effectiveness of Zirconia Crowns Versus Metal Crowns in Anterior Teeth: In vitro Study.

Background: The selection between Zirconia crowns and metal crowns for anterior teeth restorations is pivotal in prosthodontics due to their distinct properties. However, a comprehensive investigation into their effectiveness in anterior tooth restorations is warranted. Materials and Methods: This in vitro study aimed to compare the effectiveness of Zirconia crowns and metal crowns in anterior teeth restorations. A total of thirty extracted human maxillary central incisors were prepared to receive crowns and randomly allocated into two groups: group A, zirconia crowns; and group B, metal crowns. The crowns were fabricated following standardized protocols and cemented onto the prepared teeth. Various tests, including fracture resistance, marginal adaptation, and color-matching assessment, were conducted on the samples. Results: The mean fracture resistance of Zirconia crowns (Group A) was determined to be 320 N (SD ± 25), whereas it was 280 N (SD ± 30) for metal crowns (Group B). Marginal adaptation assessment revealed a mean gap width of 50 microns (SD ± 10) for Zirconia crowns and 70 microns (SD ± 15) for metal crowns. Evaluation of color matching showed a higher percentage of acceptable matches for Zirconia crowns compared to metal crowns. Conclusion: Zirconia crowns exhibited superior fracture resistance, marginal adaptation, and color matching in comparison to metal crowns for anterior teeth restorations. These findings advocate for Zirconia crowns as a more effective choice for restoring anterior teeth, offering both strength and esthetic appeal.

In Vitro Comparative Analysis of Digital Versus Conventional Impressions in Fixed Prosthodontics.

Background: In the realm of fixed prosthodontics, the transition from conventional to digital impressions has been a subject of ongoing debate. This study aims to provide a comparative analysis of digital versus conventional impressions in terms of accuracy and efficiency. Materials and Methods: Twenty patients requiring fixed prosthodontic treatment were selected for this study. Each patient received both digital and conventional impressions. The digital impressions were obtained using an intraoral scanner, while conventional impressions were taken using polyvinyl siloxane material. The impressions were then used to fabricate fixed prostheses for each patient. Accuracy was assessed through measurement of marginal fit using a standardized technique, and efficiency was evaluated based on time taken for impression procedures. Results: The mean marginal discrepancy for digital impressions was found to be 38 micrometers (±5), whereas for conventional impressions, it was 45 micrometers (±7). Additionally, the average time taken for digital impressions was 12 minutes, compared to 20 minutes for conventional impressions. Conclusion: Digital impressions demonstrated superior accuracy and efficiency compared to conventional impressions in fixed prosthodontics.

A Comprehensive Case Report on the Fabrication and Rehabilitation with Customized Eye Prosthesis.

This case report presents the clinical and technical aspects of fabricating and rehabilitating a patient with a custom-designed ocular prosthesis following enucleation due to ocular malignancy. The report details the patient's history, clinical examination, and the step-by-step process of prosthesis fabrication. The aim is to highlight the importance of a multi-disciplinary approach involving ophthalmologists and maxillofacial prosthodontists in providing optimal esthetic and functional outcomes for patients with ocular defects.

Assessment of Prosthodontic Status and Treatment Needs of Patients Visiting Dental Institutions of Punjab.

Background: This study was conducted to assess the prosthodontic status and treatment needs of patients visiting dental institutions of a known population. Material and Methods: This study comprised a total of 100 participants. The research excluded patients who did not have any prosthodontic appliances or who had dental crowns (no missing teeth). The subjects involved in the study had dental bridges, dentures, removable partial dentures, or a combination of the two. Subjects in the research were asked to tell their education, oral hygiene routines, and dentist visit behaviors. The data collected was utilized to determine the association between the variables and prosthodontics status. A thorough clinical examination of these subjects was done. The data had been analyzed using the statistical program SPSS 13. The analyses were carried out using Chi-square tests and the appropriate C-coefficient. Results: In this study, there were 50 males and 50 females. Out of 100 subjects, 45 subjects were found to be completely edentulous without any prosthodontic appliance. Complete dentures were noticed in 11 subjects, removable dentures in 29 subjects, and fixed appliances in 15 subjects. Conclusion: This survey presented that most of the subjects were completely edentulous without any prosthetic appliance. Examination of such subjects must be done on a regular basis and an appropriate treatment plan must be constructed for the well-being of these patients.

Flexural strength, fracture toughness, translucency, stain resistance, and water sorption of 3D-printed, milled, and conventional denture base materials.

PURPOSE: To compare mechanical, optical, and physical properties of denture base materials fabricated with various 3D printing systems to reference milled and conventionally heat-processed denture base materials. MATERIALS AND METHODS: Specimens of denture base materials were either 3D-printed (DLP in-office printer, CLIP laboratory printer, or material jetting laboratory printer), milled, or heat processed. 3-point bend flexural strength testing was performed after 50 hours of water storage following 1hour of drying (dry testing) or in 37°C water (wet testing). Fracture toughness was performed with a notched beam specimen after 7 days of water storage and tested dry. The translucency parameter was measured with 2 mm thick specimens. Stain resistance was measured as color change following 14 days of storage in 37°C coffee. Water sorption was measured following 7 days of storage in 37°C distilled water. RESULTS: For dry testing, all but one of the 3D-printed materials attained higher or equivalent flexural strength as the reference materials. For wet testing, all 3D-printed materials attained higher or equivalent strength as the reference materials and dry-tested materials. For 3D-printed materials, wet testing increased displacement before fracture whereas it decreased displacement for the reference materials. Only two of the 3D-printed materials had similar fracture toughness as the reference materials. One of the 3D-printed materials was more translucent and one was more opaque than the reference materials. Only one of the 3D-printed materials absorbed more water than the reference materials. CONCLUSION: 3D-printed denture base materials have mostly equivalent mechanical, optical, and physical properties to conventional and milled denture base materials.

Examining gaze behavior in undergraduate students and educators during the evaluation of tooth preparation: an eye-tracking study.

BACKGROUND: Gaze behavior can serve as an objective tool in undergraduate pre-clinical dental education, helping to identify key areas of interest and common pitfalls in the routine evaluation of tooth preparations. Therefore, this study aimed to investigate the gaze behavior of undergraduate dental students and dental educators while evaluating a single crown tooth preparation. METHODS: Thirty-five participants volunteered to participate in the study and were divided into a novice group (dental students, n = 18) and an expert group (dental educators, n = 17). Each participant wore a binocular eye-tracking device, and the total duration of fixation was evaluated as a metric to study the gaze behavior. Sixty photographs of twenty different tooth preparations in three different views (buccal, lingual, and occlusal) were prepared and displayed during the experimental session. The participants were asked to rate the tooth preparations on a 100 mm visual analog rating scale and were also asked to determine whether each tooth preparation was ready to make an impression. Each view was divided into different areas of interest. Statistical analysis was performed with a three-way analysis of the variance model with repeated measures. RESULTS: Based on the participants' mean rates, the "best" and the "worst" tooth preparations were selected for analysis. The results showed a significantly longer time to decision in the novices compared to the experts (P = 0.003) and a significantly longer time to decision for both the groups in the best tooth preparation compared to the worst tooth preparation (P = 0.002). Statistical analysis also showed a significantly longer total duration of fixations in the margin compared to all other conditions for both the buccal (P < 0.012) and lingual (P < 0.001) views. CONCLUSIONS: The current study showed distinct differences in gaze behavior between the novices and the experts during the evaluation of single crown tooth preparation. Understanding differences in gaze behavior between undergraduate dental students and dental educators could help improve tooth preparation skills and provide constructive customized feedback.

Implant Treatment in Patients With Autoimmune Diseases: A Systematic Review and Analysis of Studies.

Dental implants provide a reliable solution for edentulous patients with autoimmune diseases improving quality of life. The present systematic review aimed to determine whether autoimmune diseases with oral manifestations could affect the survival rate of dental implants. A systematic search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA), using Google Scholar and PubMed electronic databases, between the year 2000 and February 2024. The eligibility criteria included human studies, in English language reporting on patients with autoimmune diseases treated with dental implants. Nineteen studies were included: nine on oral lichen planus (OLP), four on Sjögren's syndrome (SS), five on epidermolysis bullosa (EB), and one on lupus erythematosus (LE). A total of 389 implants in 142 patients with OLP showed a survival rate (SR) of 94.6%, while 316 implants in 111 patients with SS had a survival rate of 95.8%. In 31 patients with EB, 181 implants were placed with a survival rate of 99.5%, and 12 implants were placed in five patients with LE with a survival rate of 100% after one year of function. Despite the heterogeneity and methodological limitations of most of the studies, the results showed that dental implant survival rates were comparable to those reported in the general population. This review suggested that dental implants are a viable treatment option for patients with autoimmune diseases. Nevertheless, proper daily oral hygiene and long-term follow-up are decisive factors for the long-term maintenance of dental implants.

Introduction and Effectiveness of Early Clinical Exposure Among Dental Students in Pre-clinical Prosthodontics.

BACKGROUND: Lack of patient contact in the pre-clinical prosthodontics curriculum makes it difficult for the students to comprehend and correlate the series of complex steps involved in complete denture fabrication. Early clinical exposure in the second year of the undergraduate program will facilitate a smooth transition of dental students from pre-clinics to clinics, thereby helping to mitigate the lacunae existing in the present curriculum. MATERIALS AND METHODS: A non-randomized prospective educational interventional study was conducted among 50 second-year dental students. Early clinical exposure in the form of clinical demonstration for complete denture steps of border molding and jaw relation was given subsequent to the completion of didactic and laboratory sessions. Pre- and post-multiple-choice question tests were conducted to explore students' knowledge. Student perception towards early clinical exposure was assessed using a self-administered anonymous questionnaire, while faculty perception was gauged with the help of in-depth interviews. RESULTS: A statistically significant difference was observed when pre- and post-multiple-choice question test mean scores were compared, showing an overall improvement in students' knowledge following early clinical exposure. Students and faculty held a positive perception towards the program and found it to be useful in enhancing the overall learning experience of the students. Faculty expressed their concern regarding limited manpower, paucity of time, and difficulty in integrating early clinical exposure into the present timetable. CONCLUSION: Early clinical exposure can be integrated into the traditional pre-clinical prosthodontics curriculum with appropriate time and manpower allocation. Faculty sensitization and training workshops need to be conducted before implementing this program.

Accuracy of conventional versus additive cast-fabrication in implant prosthodontics: A systematic review and meta-analysis of in vitro studies.

PURPOSE: Additive cast-fabrication has yet to be used as commonly in implant prosthodontics as conventional methods. This review aimed to investigate the accuracy of additive cast-fabrication in implant prosthodontics. STUDY SELECTION: The study protocol was registered in the PROSPERO database (CRD42022374972). Reporting was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, following the Cochrane Handbook. Two-arm interventional studies that matched the PICO were included (Population: dental typodonts with implants, Intervention: additive cast-fabrication, Comparator: conventional cast-fabrication, Outcome: positional deviations). A systematic search was conducted in three databases: PubMed (MEDLINE), EMBASE, and the Cochrane Library (CENTRAL). RESULTS: Seven papers were included in the analysis of horizontal, vertical, and root mean square (RMS) deviations. No significant differences were observed between groups. The overall vertical mean deviation of the intervention group was -4.15 µm [-24.88; 16.57], and the pooled mean absolute deviation was 22.43 µm [8.33; 36.54]. In the control group, these values were 19.67 µm [-32.71; 72.04] and 24.62 µm [0.00; 59.42], respectively. The overall horizontal mean deviation in the intervention group was 21.29 µm [-77.10; 119.68], and the pooled mean absolute deviation was 26.96 µm [0.00; 70.81]. In the control group, the overall mean was 1.45 µm [-32.26; 35.15] and the pooled mean absolute deviation was 25.05 µm [9.08; 41.01]. The mean RMS was only slightly larger in the intervention group, with the value of 14.74 µm [-107.26; 136.74]. CONCLUSIONS: Additive cast-fabrication is as accurate as the conventional method for the position of implant analogs.

Crafting Confidence: A Comprehensive Case Study of Full-Mouth Reconstruction Utilizing Implant-Supported Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) Zirconia Restorations.

A 67-year-old male patient reported to the department with a chief complaint of tooth mobility. The patient presented with a medical history of diabetes for which he was on medication, and he also reported a history of chronic periodontitis. After a thorough assessment of the patient, a proper treatment plan was designed, which included full-mouth rehabilitation, prior to which the patient was advised full-mouth extraction. Six implants were inserted into the mandibular and maxillary arches as part of the treatment. After the implant was placed, zirconia was the preferred choice for the restoration because of its superior aesthetic results. Polyvinyl siloxane impression material was used to make implant impressions after an eight-week healing period. The case report provides the technique for the current approach to full-mouth rehabilitation with all six concepts of implant placement. In these situations, it is crucial to plan and insert implants correctly and adhere to the entire treatment plan. Restorations were performed using the latest computer-aided design/computer-aided manufacturing (CAD/CAM) technologies for a more aesthetically pleasing result. The case study highlights the significance of meticulous preparation and implementation for the accomplishment of successful full-mouth rehabilitation.

Fracture strength of cad-cam milled polyetheretherketone (PEEK) post-cores vs conventional post-cores; an in vitro study.

Background: The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores. Methods: Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (n = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick® glass fiber post-core (Group GF), zirconia post-core (Group Z), metal (Cr-Co) post-core (Group M), PEEK post-core without filler (Group UP), PEEK post-core with 20% TiO2 Filler (Group TP), and post-core with 20% ceramic filler (Group CP). Following the application of posts to post spaces, copings were created and cemented on the samples. With the universal tester, a force was applied to the long axis of the tooth with a slope of 135°. The mean fracture strength (N) between the groups was statistically evaluated using one-way ANOVA, and pairwise mean differences were detected using post hoc Tukey's HSD test among the groups. Results: According to the results of the statistical analysis, a significant difference was found between the groups in terms of mean fracture resistance (p < 0.05). Group Z (409.34 ± 45.72) was significantly higher than Group UP (286.64 ± 37.79), CP (298.00 ± 72.30), and TP (280.08 ± 67.83). Group M (376.17 ± 73.28) was significantly higher than Group UP (286.64 ± 37.79) and Group TP (280.08 ± 67.83). There were no statistically significant differences between the means of the other groups (p > 0.05). Among all the groups, Group Z exhibited a higher prevalence of repairable failure modes, while the rest of the groups predominantly experienced irreparable failure modes. Conclusion: In our study, zirconia and metal post-core samples showed higher average fracture strength values than PEEK post-cores groups. Repairable failure modes were more common in the zirconia post-cores, whereas the opposite was observed in the other groups. Further experimental and clinical trial studies are needed before PEEK materials can be used as post materials in the clinic.

Effects of facial forms and midline deviations and rolls on female facial beauty according to laypeople, orthodontists, and prosthodontists or restorative dentists.

No study has examined the simultaneous effect of facial forms, midline deviations and midline angulations on facial beauty. Therefore, this comprehensive study aimed to evaluate these and many other hypotheses. This psychometric study was performed on 15,042 observations. A female frontal photograph was edited to 45 perceptometric images with controlled anatomical alteration: 3 facial forms (euryprosopic [brachyfacial], mesoprosopic [mesofacial], leptoprosopic [dolichofacial]), each having either 9 bidirectional midline deviations (0, 1, 2, 3, and 4 mm deviated to the left and right) or 7 bidirectional midline angular deviations (0°, 5°, 10°, and 15° deviated to the left and right). One of the photographs were repeated. These 46 images were esthetically judged by 327 participants (243 laypeople, 49 orthodontists, and 35 'prosthodontists or restorative dentists'). Hierarchical mixed-model multiple linear regressions and post hoc tests were adopted to evaluate the simultaneous impacts of the photomodel's facial forms, midline deviations to the right or left, and midline rolls to the right or left plus sex, age, experience, and dental specialty of the referees on their perception of facial beauty as well as the tolerable zones of midline alterations. These were also done separately for each specialty group, and also for each facial face. Ideal combinations of anatomic features were determined using repeated-measures ANOVAs. Differences between esthetic preferences of different groups in terms of each image were assessed using one-way ANOVAs and t-tests (α = 0.05, α = 0.008, α = 0.001). All 5 anatomical features significantly and independently influenced perception of facial beauty. The tolerance threshold for midline deviations was 1 mm deviations to the right and left sides. For midline rolls, the only tolerable form was the no-roll ('on') midline; the judges preferred right-oriented defects over left-sided ones. The most beautiful facial form was mesoprosopic, followed by leptoprosopic. Men perceived the female face slightly more attractive than did women. The viewers' specialty (or lack of it), their age, or their experience did not affect their esthetic preferences. Predictors of esthetic preferences were all 5 anatomical features plus views' sex, but not their dental specialty, age, or experience. Zones of acceptability and also the ideal range of anatomical features were determined.

The impact of various substrates, ceramic shades, and brands on the ultimate color and masking capacity of highly translucent monolithic zirconia: an in vitro study.

This study aimed to examine the impact of substrates, ceramic shades, and brands on the color and masking ability of highly translucent monolithic zirconia (HTMZ) using CIELab and CIEΔE2000 metrics. A total of 156 1-mm thick HTMZ disks in shades A1, A2, and A3 were produced using Dental Direkt and Kerox zirconia brands. Four 3-mm thick substrates (nickel-chromium alloy, non-precious gold alloy (NPG), zirconia shade A2, and resin composite shade A2) were prepared. HTMZ disks were overlaid on these substrates, and color measurements were taken with a spectrophotometer. Color differences (ΔE) were analyzed using CIELab and CIEΔE2000 formulas. The influence of brand, shade, substrate, and their interactions on ΔE values was assessed with a General Linear Model (GLM) and LSD pairwise comparison test. Spearman's correlation test examined the relationship between CIELab and CIEΔE2000 values. Results indicated that ΔEab was significantly influenced by substrate type and shade, while ΔE2000 was also affected by the ceramic brand. Mean color differences across ceramic-substrate groups were within clinically acceptable and perceptible ranges (clinically perceptible: ∆Eab ≥ 1.3 and ∆E2000 ≥ 0.8; clinically acceptable: 0.8 < ∆E2000 ≤ 1.8 and 1.3 < ∆Eab ≤ 2.7), except for NPG, which had ΔE values exceeding the perceptible range (ΔE2000: 1.1 ± 0.11 to 1.8 ± 0.31; ΔEab: 1.61 ± 0.15 to 2.16 ± 0.36). A significant correlation (r = 0.974, P < 0.001) was found between ΔEab and ΔE2000. Various ceramic brands and shades led to notable ΔE variations, yet average color differences within all ceramic-substrate groups remained clinically acceptable. Both ΔEab and ΔE2000 were reliable methods with a strong correlation for measuring color differences.