litrature review about dental cad cam system

litrature review about dental cad cam system

1. The article titled "Wear Characteristics and Volume Loss of CAD/CAM Ceramic Materials: Wear of All-Ceramic Restorations" published in the Journal of Prosthodontics discusses the wear behavior and volume loss of CAD/CAM ceramic materials, specifically zirconia (ZR) and lithium disilicate (LD). The study aims to address the limited research regarding the wear of dental ceramics opposing each other, which is critical due to the increasing use of these materials in dental restorations. Purpose The study investigates how the wear potential and behavior of CAD/CAM ZR and LD materials are influenced by their surface finishes.

2. Materials and Methods A total of 20 all-ceramic plates were used, consisting of 10 monolithic zirconia plates and 10 lithium disilicate plates. The plates were sectioned and treated according to manufacturer recommendations, including crystallization and glazing. Two surface finishes were evaluated: glazed (G) and glazed then polished (GP). A sphere-on-plate tribometer system was utilized to simulate wear, and artificial saliva was used as a lubricant. The COF, volume loss, and surface roughness were measured, and statistical analysis was performed using two-way ANOVA and Bonferroni post hoc tests [[2-3]].

3. Results 1. Coefficient of Friction (COF) : The study found that material type significantly affected the COF, with LD exhibiting a higher COF than ZR (p = 0.002). The surface finish did not significantly influence the COF [[5]]. 2. Surface Roughness : ZR exhibited significantly lower surface roughness compared to LD. Surface finish also impacted roughness, with polished specimens being rougher than glazed ones [[5]]. 3. Volume Loss : ZR demonstrated less volume loss compared to LD. The interaction between material and surface finish was statistically significant, indicating that LD had higher volume loss than ZR, particularly in both glazed and polished finishes [[2-3]]. 4. Wear Mechanisms : Scanning Electron Microscopy (SEM) revealed different wear patterns. LD specimens showed signs of a three-body wear mechanism, characterized by grooving, especially in the polished specimens. In contrast, ZR specimens showed minimal wear scars, suggesting better wear resistance [[5-6]].

4. Conclusions The study concluded that ZR is more resistant to wear than LD in a simulated masticatory environment. The differences in wear behavior can be attributed to the material hardness and the presence of three-body wear in LD due to accumulated debris. The findings emphasize the importance of considering material selection and surface finish in the clinical use of all-ceramic restorations [[6-9]]. Clinical Implications The results indicate that zirconia restorations should be polished carefully after adjustments to maintain their wear resistance. Adjustments to lithium disilicate surfaces should ideally be made while submerged in a lubricant to minimize wear [[9]].

5. The research article titled "Trueness analysis of zirconia crowns fabricated with 3-dimensional printing" evaluates the potential of 3D printing technology for producing zirconia (ZrO2) crowns in dentistry, comparing its accuracy to the conventional computer-aided design and computer-aided manufacture (CAD-CAM) milling method. The authors, highlight the advantages of 3D printing, particularly its reduced material waste compared to traditional subtractive manufacturing methods, which can waste up to 90% of the prefabricated block material

6. The study's purpose was to assess the 3D trueness of zirconia crowns produced via 3D printing and to determine if this method could serve as an effective alternative for dental ceramic restorations. The methodology involved preparing a typodont tooth for a ceramic crown, designing a digital crown using CAD software, and fabricating the crowns with both a 3D-printing system and a dental milling machine. After fabrication, the crowns were scanned using a dental laboratory scanner, and various surface areas (external, intaglio, marginal, and intaglio occlusal) were analyzed for trueness using advanced 3D inspection software

7. Results indicated that the trueness of the 3D-printed crowns was comparable to that of the CAD-CAM crowns, with statistical analysis showing no significant difference in accuracy between the two methods. Specifically, the external surface of the 3D-printed crowns had a root mean square (RMS) value slightly higher than that of the milled crowns; however, the intaglio surfaces demonstrated lower RMS values in the 3D-printed group, indicating better accuracy in those areas In summary, the study supports the hypothesis that 3D printing technology can effectively produce zirconia crowns with trueness comparable to CAD-CAM milling, potentially revolutionizing restorative dentistry by minimizing material waste and expanding fabrication options 

8. Crown Fabrication : The 3D-printed zirconia crowns were fabricated using a ceramic 3D-printing system (CERAMAKER 900) that employs hydroxyapatite for custom manufacturing. The process involved mixing ZrO2 paste with liquid photosensitive resin, which was then selectively solidified under ultraviolet laser radiation. A maxillary right second molar typodont tooth was prepared for a ceramic crown by an experienced prosthodontist. The tooth was scanned using a dental laboratory scanner, and a ceramic crown was designed based on this digital scan, saved as a standard tessellation language (STL) file. Comparison with CAD-CAM : For comparison, crowns were also fabricated using a CAD-CAM system (DWX-50) from a ZrO2 block. Both methods produced ten crowns each for evaluation. Scanning and Evaluation : After fabrication, the crowns were scanned using a dental blue light scanner to collect data. The scanned data were divided into four parts (external surface, intaglio surface, marginal area, and intaglio occlusal surface) for analysis. The trueness of each part was assessed using 3D inspection software, with the root mean square (RMS) calculated to evaluate accuracy.

9. Zirconia ceramics are favored for dental crowns due to their excellent mechanical properties, though traditional CAD-CAM milling processes result in significant material waste . Additive manufacturing (AM), including 3D printing, offers a more waste-efficient alternative but has seen limited application in ceramic restorations, particularly zirconia crowns . This in vitro study aimed to evaluate the 3D trueness of zirconia crowns fabricated by 3D printing compared to those made by CAD-CAM milling . A typodont tooth was prepared, and digital crowns were designed and processed either through a 3D printer or a dental milling system . The study found that the trueness of 3D-printed zirconia crowns was comparable to that of CAD-CAM crowns, with statistical significance indicating no worse performance . Key areas evaluated for trueness included the external surface, intaglio surface, marginal area, and intaglio occlusal surface . The results showed that 3D-printed crowns meet surface trueness requirements and could potentially reduce material waste in clinical applications . Limitations of the study include the fact that the tooth preparation may not fully represent clinical conditions, emphasizing the need for further research . The research highlights the potential of 3D printing technology in dental applications, particularly for fabricating zirconia crowns

10. The article titled "Optical properties of CAD–CAM ceramic systems" by Alvaro Della Bona and published in the journal of dentistry in 2014 . It emphasizes the significance of aesthetic materials that closely resemble the optical properties of natural teeth, which include light reflection, diffusion, absorption, and transmission. The study aims to evaluate the direct transmittance, translucency, opacity, and opalescence of various CAD–CAM ceramic systems and to explore the correlation between translucency parameters and contrast ratios.

11. The materials and methods used in the study on the optical properties of CAD–CAM ceramic systems are as follows: 1. **Ceramic Systems Evaluated**: - The ceramic systems evaluated included shades A1, A2, and A3 from various brands: - IPS e.max CAD (Lithium disilicate-based glass–ceramic) - IPS Empress CAD (Leucite-reinforced glass–ceramic) - Paradigm C (Leucite-reinforced glass–ceramic) - VITABLOCS Mark II (Feldspathic ceramic) [[2]]. 2. **Specimen Fabrication**: - Specimens measuring 10 mm x 20 mm x 1 mm were fabricated using a CAD–CAM system (Sirona CEREC inLab MC XL). - Each specimen was polished to a thickness of 1.0 ± 0.01 mm [[2]]. 3. **Direct Transmittance Measurement (T%)**: - An ultraviolet–visible (UV/vis) spectrophotometer (Lambda 20) was used to measure the direct transmittance (T%) of light in the wavelength range of 400–780 nm [[3]]. 4. **Translucency Parameter (TP)**: - A dental spectrophotometer (VITA Easyshade Advance) was employed to record the CIELAB coordinates (L*, a*, b*) of the ceramic samples. - The translucency parameter (TP) was calculated using the color difference between readings on black and white backgrounds [[3]]. 5. **Contrast Ratio (CR)**: - The spectral reflectance (Y) was calculated using the L* values recorded for the samples over black and white backgrounds, and the contrast ratio (CR) was derived from these reflectance values [[3]]. 6. **Opalescence Parameter (OP)**: - The opalescence parameter (OP) was estimated using the difference in a* and b* coordinates recorded from the ceramic specimens placed on black and white backgrounds [[3]]. 7. **Statistical Analysis**: - Data were statistically analyzed using variance accounting for (VAF) coefficients, one-way ANOVA, Tukey’s test, Bonferroni correction, and Pearson's correlation [[3]]. The study aimed to evaluate the optical properties such as transmittance, translucency, opacity, and opalescence of CAD–CAM ceramic systems and their correlations with various parameters [[2]].

12. Key findings revealed that the transmittance values of certain ceramics were dependent on the wavelength, showing a slight increase up to approximately 550 nm before changing behavior as the wavelength increased. Translucency parameter (TP) and contrast ratio (CR) values showed a strong correlation (r² = 0.97), indicating that as translucency decreases, the contrast ratio increases. The study concluded that the microstructure of CAD–CAM ceramic systems significantly influences their optical properties, and it also emphasized that other optical properties, alongside shade, are crucial for achieving a natural appearance in dental ceramics.

13. In conclusion, the authors assert that the optical properties of CAD–CAM ceramics are influenced by their microstructure and composition, and they advocate for a more comprehensive investigation into these properties to enhance aesthetic outcomes in dentistry. The article ends with acknowledgments for funding support and references to related studies in the field.

14. The systematic review and meta-analysis titled "Clinical Performance of CAD/CAM All-Ceramic Tooth-Supported Fixed Dental Prostheses" by Babak Saravi et al., published in 2021, investigates the mid- and long-term clinical performance of computer-aided design and manufacturing (CAD/CAM) ceramic restorations as alternatives to traditional metal-ceramic fixed dental prostheses (FDPs). The study focuses on survival and success rates of tooth-supported zirconia and lithium disilicate-based FDPs.

15. Materials and Methods The systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A literature search was performed from inception to January 2020, targeting prospective studies focused on the clinical performance of CAD/CAM fabricated all-ceramic fixed dental prostheses (FDPs). The search included studies published in English or German, utilizing a combination of medical-subject heading ( MeSH ) and free-text terms across Medline (via OVID) and Web of Science. Hand searches of reference lists from retrieved studies were also conducted. Inclusion Criteria: Human patients with tooth-borne CAD/CAM manufactured all-ceramic FDPs. Studies assessing survival rates and complications within a prospective design. Exclusion Criteria: Metal and metal-ceramic restorations Implant-borne prostheses Hybrid bridges Cantilever bridges Crowns Animal studies In vitro studies Retrospective studies Case studies Studies in languages other than German or English A total of 18 publications met the inclusion criteria after screening 7104 studies

16. Survival and Success Rates: - The pooled estimated survival rates for 1, 5, and 10 years ranged from approximately 93.80% to 94.66%, 89.67% to 91.1%, and 79.33% to 82.20%, respectively. - Success rates, which considered any type of intervention but excluded failures, ranged from 94.53% to 96.77% for 1 year, 90.89% to 94.62% for 5 years, and 81.78% to 89.25% for 10 years [[3]]. Complications: The most frequent cause of failure was secondary caries, followed by chipping of the veneering. The review found that chipping was the most common complication requiring intervention but not leading to the removal of the prosthesis [[4]]. The risk of bias was assessed, revealing that 7 studies had low risk, 8 had moderate risk, and 3 had serious risk [[5]]. Clinical Implications: The findings suggest that CAD/CAM all-ceramic FDPs show promising survival and success rates over extended periods, indicating they can be a viable alternative to metal-ceramic systems in fixed prosthodontics. However, the authors emphasize the need for more prospective studies focusing on long-term performance to further validate these results [[6]]. Result

17. Conclusion : The review concludes that while CAD/CAM zirconia and lithium disilicate-based FDPs exhibit favorable clinical outcomes, challenges such as chipping and secondary caries need further investigation. The study underscores the potential for a shift towards all-ceramic solutions in modern dentistry, contingent on ongoing advancements in materials and technology