Fixed dental crowns are significant in cases of large caries, fracture, endodontic treatment, and developmental defects, as well as significant loss of tooth structure.[1] The long-term clinical success of a crown is not only established in terms of oral function and occlusion, but also in terms of marginal adaptation, fracture resistance, biological compatibility, esthetics and patient satisfaction.[2] Metal-ceramic crowns have traditionally been considered as a reliable conventional reference standard due to their favourable mechanical properties and documented longevity.[3] Recent clinical studies suggest that metal-ceramic single crowns can be considered clinically reliable with approximately 97.1% five-year success.[4]

Although conventional metal-ceramic crowns are durable, there are a number of limitations. It is possible that the presence of a metallic substructure may affect some of the optical properties, especially in the cervical region, and can

sometimes lead to a metallic dark border or to a reduction of translucency.[5] In addition, there are several laboratory steps to be taken in fabrication, such as impression/cast fabrication, waxing, casting, metal finishing, ceramic application, and firing.[6] These steps are sequential in nature, so there could be some inconsistencies in the marginal accuracy or the quality of the restorations. This has led to the emergence of computer-aided design and computer-aided manufacturing (CAD/CAM) technologies, which have become more popular due to their ability to produce more highly esthetic, biocompatible, and efficiently fabricated restorations.[7]

In the field of restorative dentistry, CAD/CAM technology has revolutionized the way restorations are acquired, designed, and manufactured, all of which are now possible with the use of computer-aided design and computer-aided manufacturing systems.[8] These materials, like monolithic zirconia and lithium-disilicate ceramics, can be finely milled, which can minimize the variation caused by the milling process and enhance workflow efficiency and repeatability.[9] A 2023 systematic review and meta-analysis of 13 studies involving 1,598 restorations in 1,161 patients concluded that there were similar biological and technical results between CAD/CAM and conventionally fabricated restorations, while there were reports of differences in esthetic complications.[10]

There has also been a growing clinical success with CAD/CAM restorations. The survival rates for monolithic CAD-CAM zirconia crowns ranged from 91% to 100% in a systematic review of 1657 restorations in 594 subjects, with a relatively short follow-up period.[11] A systematic review and meta-analysis of zirconia-based and metal-ceramic fixed dental prostheses showed that zirconia offers compelling clinical evidence that it would be a viable alternative to metal-ceramic restorations.[12] Importantly, a recently published and systematic review of 64 clinical studies including over 11,500 single crowns indicated that the 5-year survival of metal-ceramic crowns was 97.1%, of monolithic zirconia crowns was 96.8%, and of monolithic lithium-disilicate crowns was 98.5%, showing that the survival of contemporary all-ceramic materials is comparable to the established metal-ceramic standard.[13]

However, the ability of a crown to survive does not necessarily translate to the performance of the clinical crown. The factors of marginal integrity, anatomical form, color match, surface characteristics, postoperative sensitivity and biological complications, ceramic chipping or fracture, loss of retention, and patient satisfaction are all equally important factors to restorative success. The variability in digital workflows, material properties, and design of preparation, manufacturing systems, operator skill, and clinical conditions can also impact results. Consequently, the results of international studies cannot be directly applied to all clinical scenarios and situations, especially in areas where CAD/CAM technology is being introduced and where there is only limited local comparative clinical evidence.

In this context, direct clinical comparison of CAD/CAM-fabricated crowns with conventional metal-ceramic crowns is clinically meaningful to evaluate whether the technological benefits of digital fabrication are clinically meaningful when it comes to patient-centered and restoration-centered outcomes. This evidence could be used to guide the clinician in the selection of restorative materials with respect to esthetics, workflow, durability, biological behavior, marginal adaptation, and overall clinical success. The present study was therefore planned to compare the clinical performance of CAD/CAM fabricated crowns with the conventional metal-ceramic crowns.

A prospective comparative clinical study was conducted at Department of Prosthodontics, over a period of 12 months, from June, 2025 to May, 2026.

The sample size was determined through the use of OpenEpi version 3.01 for comparison of two independent proportions. Based on previously reported comparative clinical evidence for the adaptation and performance of CAD/CAM and conventional crowns, an expected difference in the clinically acceptable outcome between the two was used, and the difference was calculated as 95% in the CAD/CAM group against 75% in the conventionally fabricated group.[14] The sample size was calculated as about 45 crowns per group with a two-sided test confidence level of 95%, a statistical power of 80% and an allocation ratio of 1:1. To account for the expected 10% loss to follow-up or exclusion of restorations over the course of the study, the sample was expanded to 50 crowns per group, yielding a final sample of 100 crowns.

Non-probability consecutive sampling was used to select participants. Patients with a single-unit full-coverage crown on a permanent tooth were included. Eligible teeth included those that had sufficient periodontal support, sufficient remaining tooth structure for crown preparation and, if applicable, sufficient remaining tooth structure for a clinically acceptable ferrule. Patients with good or adequately controlled oral hygiene and who were willing to return for scheduled follow-up examinations were included. Anterior teeth and posterior teeth were all acceptable as long as they met the restorative criteria of the study. Patients who had a systemic disease which was not controlled, severe periodontal disease, poor oral hygiene, untreated dental caries or insufficient remaining tooth structure for crown restoration were excluded. Teeth with active endodontic disease, mobility, extensive periapical disease and poor CRR were also excluded. Severe bruxism and other parafunctions that could negatively impact the longevity of the crown were not included unless managed. Patients who refused or could not make it to follow-up appointments were also excluded.

Ethical approval was received from the institutional review committee, and eligible patients were explained the research purpose and methods and gave written informed consent before participating in the study. The baseline demographic and clinical data such as age, sex, treated tooth, tooth location, indication for crown placement, periodontal status, and relevant dental history were documented on the data collection proforma.

Selected teeth were clinically inspected, and the appropriate preparation was carried out using standard crown preparation principles. The preparation aimed to achieve adequate reduction, a clearly defined finishing line, adequate occlusal clearance, and appropriate taper. In the CAD/CAM group, a digital intraoral scan was taken after the preparation of the teeth. The preparation was digitally designed with the help of CAD, and the definitive crown using the chosen CAD/CAM restorative material was produced in a computer-controlled milling system. The restoration was then completed, polished/glazed as per the manufacturer's instructions, clinically assessed, and bonded with a suitable luting cement.

In the conventional group, conventional impressions were taken after the standardized tooth preparation, and a working cast was made. A conventional laboratory process of wax pattern making, metal coping casting, application and firing of porcelain, finishing, and glazing was used to create the crown. Before definitive cementation, the completed crown was clinically assessed for marginal adaptation, proximal contacts, occlusion, contour, and esthetics.

Each cementation was evaluated clinically for marginal adaptation, anatomical form, marginal discoloration, surface texture, postoperative sensitivity, secondary caries, fracture or chipping of the ceramics, loss of retention, and periodontal condition. The clinical assessment of marginal adaptation was carried out with a dental explorer and, if needed, with X-rays. Standardized modified USPHS/FDI-based criteria were used to record clinical performance. A structured patient satisfaction rating scale was used to document patient satisfaction with esthetics, comfort, function, and overall acceptance. The assessment protocol was used for both groups to avoid measurement bias.

Follow-up exams were conducted at baseline, 3 months, 6 months, and 12 months post-cementation. All biological or technical problems were recorded during the follow-up period. A crown was deemed a clinical success if it was not fractured, lost, developing secondary caries, was not excessively marginal, or had other complications that necessitated replacement.

The data obtained were entered and analysed using IBM SPSS Statistics 26.0. Data on continuous variables (age and clinical assessment scores) were summarized as means ± SD or medians with interquartile ranges (IQR), depending on the distribution of the data. All categorical responses were provided as frequencies and percentages, such as gender, tooth location, clinical success, marginal discoloration, fracture/chipping, secondary caries, loss of retention, and periodontal complications.

The Shapiro–Wilk test was used to determine the normality of continuous variables. The independent-samples t test was used to compare normally distributed continuous variables between the CAD/CAM and conventional groups. The Pearson chi-square test and Fisher's exact test was used to compare categorical variables. The repeated-measures analysis or non-parametric equivalent was used to evaluate changes in clinical outcomes across follow-up visits. Risk estimates with 95% confidence intervals were used to compare the clinical success rates between the two groups. If the number of failures was adequate in the follow-up period, survival analysis using the Kaplan–Meier method was used to compare crown survivability between the two groups. A p-value ≤0.05 was considered statistically significant.

There were no statistically significant differences between the two groups with respect to any of the baseline measurements, including age, sex, tooth type, tooth location, arch type, indication for crown placement, and periodontal status, and thus adequate baseline comparability between the two groups was obtained (Table 1).

At 12 months, CAD/CAM-fabricated crowns showed significantly better marginal adaptation and overall clinical success than conventional metal-ceramic crowns. CAD/CAM crowns had a lower occurrence of marginal discoloration, postoperative sensitivity, secondary caries, fracture/chipping, and loss of retention, although these differences were not statistically significant (Table 2).

CAD/CAM crowns exhibited significantly lower gingival index scores and marginal discrepancy, thus providing good marginal fit and periodontal response. Additionally, the group receiving CAD/CAM crowns reported significantly higher esthetic, comfort and overall satisfaction scores, with no significant differences noted between the groups for plaque accumulation and functional satisfaction (Table 3).

There were no significant differences between the groups in the frequency of any of the complications observed during the 12-month follow-up period, nor were there any significant between-group differences in the changes in the number of patients with marginal discoloration, postoperative sensitivity, fracture/chipping, secondary caries, or loss of retention (Table 4).

The survival analysis revealed that there was a significantly more favorable cumulative survival pattern for CAD/CAM crowns during a 12-month observation period than for conventional crowns, with the difference between the survival curves being statistically significant on the Kaplan–Meier log-rank test (Table 5).

Table 1. Baseline demographic and clinical characteristics of the study groups (n=100)

Table 2. Clinical performance and complications of crowns at 12-month follow-up

Table 3. Marginal discrepancy, periodontal parameters, and patient satisfaction at 12 months

Table 4. Changes in clinical outcomes from baseline to 12 months

Table 5. Crown survival during 12-month follow-up

The present study showed that the clinical performance of CAD/CAM fabricated crowns was more favorable than that of metal-ceramic crowns fabricated in the conventional method in the short term. CAD/CAM restorations also demonstrated significantly better marginal adaptation and overall clinical success, in addition to lower marginal discrepancies and gingival index scores at 12 months. The results of this study are consistent with other studies that have demonstrated the potential of digital fabrication to enhance the precision and biological performance of fixed prosthodontic restorations. The mean marginal discrepancy of the CAD/CAM group was 72.4 μm and 94.7 μm for the conventional group, suggesting a clinically significant improvement in the marginal fit of the CAD/CAM group.

The results of the present study were also in accordance with the results of Sadr et al. (2022), which directly compared CAD/CAM and lost-wax fabrication of metal-ceramic crowns and assessed the internal fit at various stages of fabrication. They concluded that fabrication method affects the accuracy of these restorations, but their tests were conducted in a laboratory setting, not a clinical setting.[15] In a similar study published in 2023, Cobalt-chromium and zirconia CAD/CAM fabricated crowns were compared to conventional metal-ceramic crowns, and the researchers found that there were significant differences in the marginal adaptation among the groups of crowns, which showed that digital fabrication is important for achieving accurate crown margins.[16]

The magnitude and direction of the difference in marginal discrepancy in the present study were also compatible with more recent evidence. The marginal gap measured using micro-CT was significantly smaller for single crowns fabricated using the digital method compared to those fabricated using conventional impressions, the values of which were approximately 43 and 60 μm, respectively, as reported by Topdagi et al. (2025). The study compared the digital and conventional impression techniques, and not CAD/CAM and conventional crown fabrication, but the results do support the role that digital workflows can play in marginal accuracy.[17]

The better clinical success achieved with CAD/CAM crowns was also confirmed by the 6-year clinical study by

Aziz et al. (2023) in which monolithic CAD/CAM lithium-disilicate crowns were compared with metal-ceramic crowns. The CAD/CAM group experienced significantly fewer complications, and 96% of the CAD/CAM crowns survived and were successful in their function after six years, compared with 90.8% CAD/CAM crown survival and 83.4% CAD/CAM crown success. Patients also showed higher preference for the esthetic outcome of CAD/CAM restorations. These results are similar to the present study, where 12-month clinical success was higher and esthetic satisfaction was significantly higher with CAD/CAM crowns.[3]

Similarly, the CAD/CAM group in this study experienced a lower rate of fracture/chipping, secondary caries, loss of retention, marginal discolouration, and postoperative sensitivity, which was directionally consistent with the results of Aziz and colleagues (2023), who found that only 2 complications occurred in CAD/CAM group versus 12 in the metal-ceramic group after long term follow-up. The rates of individual complications in the current study did not achieve statistical significance, likely due to the limited number of adverse events and follow-up period of 12 months.[3]

The periodontal findings were also good for CAD/CAM restorations. The CAD/CAM group showed significantly lower Gingival Index, indicating that the better marginal adaptation could be associated with better gingival health. This interpretation is biologically feasible, as the ability to correctly adapt crown margins can help remove plaque-retentive areas and aid in the maintenance of periodontal tissues. In this 5-year randomized clinical trial (RCT), which evaluated digital translucent zirconia and metal-ceramic posterior crowns, both groups showed similar periodontal outcomes; however, the gingival index values fluctuated over time. The mechanical complications occurred primarily in the metal-ceramic group and were associated with slight chipping of the ceramics. Therefore, the present results are aligned with literature demonstrating that modern, digitally manufactured crowns can result in the maintenance of a favorable periodontal health status; however, further follow-up studies are needed to determine if there is a continued difference in gingival health.[18]

On the other hand, Gseibat et al. (2025) showed 100% survival for both digitally fabricated translucent zirconia and metal-ceramic posterior crowns, highlighting that recent metal-ceramic restorations can have excellent longevity when made within a digital workflow. This difference between the findings and the present results could be due to differences in material, material processing, cementation protocol, patients, sample size, and follow-up period.[19]

The overall good life expectancy of CAD-CAM restorations has been corroborated by the evidence presented by Wierichs et al. (2024). CAD/CAM implant-supported all-ceramic crowns were found to have a success rate of around 97% in a prospective multicenter cohort, with the laboratory processing demonstrating significantly higher success rates than the chairside process.CAD/CAM implant-supported all-ceramic crowns have been reported with a success rate of around 97% in a 12-year follow-up multicenter cohort, while the success of the laboratory processing was significantly higher than the success of the chairside processing. This has to be understood as it reports that the clinical performance of CAD/CAM is not the same as the clinical performance of the operator; the manufacturing environment, selection of material, cementation, and quality-control procedures could all play a role in determining the clinical performance of the CAD/CAM product and, in turn, the clinical survival of the crown.[20]

The overall results of the present study indicated that CAD/CAM produced crowns offer a clinically beneficial alternative to traditional metal-ceramic crowns, especially regarding marginal adaptation, gingival response, overall clinical success, esthetic satisfaction, and short-term survival. The agreement of the results obtained with the marginal fits with the more recent laboratory and clinical evidence makes this conclusion more plausible. Relatively short follow-up time (12 months) and small sample size, however, preclude conclusions about long-term survival. Therefore, larger prospective randomized studies with longer observation periods, standardized CAD/CAM materials, impression technique, cementation technique, and clinical evaluation criteria are warranted to ascertain whether the above advantages are retained throughout the service life of the CAD/CAM crowns.

Limitations

There were some limitations of this study. The small number of participants and single-center nature of the design may have restricted the validity of the results. Long term crown survival and late biological or mechanical complications were not assessed in the follow-up period, which was limited to 12 months. Furthermore, this study did not assess the effect of various CAD/CAM materials, cementation techniques, operator experience, and specific CAD/CAM manufacturing systems on clinical outcomes. The evaluation of the periodontal and esthetic results could also have been affected by the examiner and the patient. More comprehensive multicenter studies with extended follow-up are thus warranted to confirm these results.

CAD/CAM fabricated crowns had better short-term clinical performance in terms of marginal adaptation, marginal discrepancy, gingival health, overall clinical success, patient satisfaction, and 12-month survival than conventionally fabricated metal-ceramic crowns. The differences in frequencies of individual complications were not statistically different between CAD/CAM crowns. These results indicate the potential use of CAD/CAM technology for modern crown preparation, but long-term studies are needed to assure that these benefits persist over time.

1. Al-Meshal, S.K., et al., Remaining tooth structure and prognosis of restored endodontically treated teeth: A systematic review. Cureus, 2025. 17(10).
2. Aldowish, A.F., et al., Occlusion and its role in the long-term success of dental restorations: a literature review. Cureus, 2024. 16(11).
3. Aziz, A. and O. El-Mowafy, Six-year clinical performance of lithium disilicate glass-ceramic CAD-CAM versus metal-ceramic crowns. The Journal of Advanced Prosthodontics, 2023. 15(1): p. 44.
4. Pjetursson, B.E., et al., A Systematic Review and Meta-analysis Evaluating the Survival, Failure, and Complication Rates of Metal-Ceramic, Veneered, and Monolithic All-Ceramic Tooth-Supported Single Crowns--Part 1. International Journal of Prosthodontics, 2026. 39(3): p. 308.
5. Haghi, H.R., et al., Effect of ceramic type, cement shade, and ceramic thickness on the optical properties of the definitive restoration and the ability to mask a metal substructure. The Journal of prosthetic dentistry, 2025.
6. Toia, M., et al., Distortion of the Implant-Framework Interface of Screw-Retained CoCr Ceramic Fixed Dental Prostheses Following Ceramic Veneering: An In Vitro Study. International Journal of Prosthodontics, 2026. 39(2): p. 243.
7. Islam, M.S., A. Al‐Fakhri, and M.M. Rahman, Computer aided design/computer aided manufacturing (CAD/CAM) technology in the undergraduate dental programs in the MENA region. European journal of dental education, 2024. 28(1): p. 142-147.
8. Ramnarayan, B., et al., Revolutionizing dental restorations: Insights into computer-aided design/computer-aided manufacturing materials–A systematic review. Dental Research Journal, 2025. 22: p. 52.
9. Zbuzant, M., Advances in Digital Dentistry Applications of CADCAM Technology. Journal of Advanced in Medicinal, Pharmaceutical and Biomedical Research (JAMPBR), 2026. 2(4): p. 346-358.
10. Ling, X. and L. Huang, Survival rates of CAD/CAM ceramic dental restorations: A meta-analysis. Medicine, 2026. 105(4): p. e47221.
11. Leitão, C.I.M.B., et al., Clinical performance of monolithic CAD/CAM tooth-supported zirconia restorations: systematic review and meta-analysis. Journal of Prosthodontic Research, 2022. 66(3): p. 374-384.
12. Chen, H., et al., Clinical performance of zirconia-based tooth-supported fixed dental prostheses: A systematic review and meta-analysis. Journal of Dentistry, 2024. 151: p. 105382.
13. Pjetursson, B.E., et al., A Systematic Review and Meta-analysis Evaluating the Survival, Failure, and Complication Rates of Metal-Ceramic, Veneered, and Monolithic All-Ceramic Tooth-Supported Single Crowns-Part 1. Int J Prosthodont, 2026. 39(3): p. 308-324.
14. Paul, N., et al., Marginal and internal fit evaluation of conventional metal-ceramic versus zirconia CAD/CAM crowns. J Clin Exp Dent, 2020. 12(1): p. e31-e37.
15. Sadr, S.M., et al., Comparison of internal fit of metal‐ceramic crowns in CAD/CAM and lost‐wax techniques in all fabrication stages through replica weighting, triple scanning, and scanning electron microscope. Clinical and Experimental Dental Research, 2022. 8(3): p. 763-770.
16. Nazarifar, A.M. and A. Davoudi, Marginal Accuracy of CAD/CAM Frameworks Fabricated by Presintered Cobalt-Chromium Alloy: A Systematic Review and Meta-analysis. International Journal of Oral & Maxillofacial Implants, 2023. 38(1): p. 181.
17. Topdagi, B., C.C. Guler, and E.G. Sultanoglu, Marginal and internal fit accuracy of single-crown restorations: the impact of digital and conventional impression techniques. BMC Oral Health, 2025. 26(1): p. 79.
18. Gseibat, M., et al., Clinical outcome of translucent zirconia and metal‐ceramic posterior crowns in a digital workflow: A 5‐year prospective randomized clinical trial. Journal of Prosthodontics, 2025. 34(6): p. 574-583.
19. Gseibat, M., et al., Clinical outcome of translucent zirconia and metal-ceramic posterior crowns in a digital workflow: A 5-year prospective randomized clinical trial. J Prosthodont, 2025. 34(6): p. 574-583.
20. Wierichs, R.J., et al., Practice-Based Study on CAD/CAM Inlays, Onlays, and Crowns: Longevity and Risks. J Dent Res, 2025. 104(11): p. 1218-1227.