Computer-aided Design Manufacturing Research Articles

Effect of speed sintering of monolithic zirconia with different yttria contents on color and crystal phase.

This study evaluated the color and microstructure of monolithic zirconia crowns with different yttrium oxide (Y2 O3 ) contents treated by conventional or speed sintering. Four types of zirconia ceramics were assessed: two monolayer zirconia, and two multilayer zirconia. The monolithic zirconia crowns were fabricated using a dental computer-aided design/computer-aided manufacturing (CAD/CAM) system and in two shades (A2 and BL). After milling, the zirconia crowns were sintered using either speed sintering or conventional sintering. For each combination of zirconia (4), shade (2), and sintering condition (2), the color parameters were determined at three positions of each of nine crowns using a non-contact dental spectrophotometer. In addition, the zirconia phases in the specimens were quantified using X-ray diffractometry. Significant differences in the ΔE00 values at different measurement positions were observed for the Multi2 crown of the BL shade group. The color difference resulting from conventional and speed sintering programs was not affected by the difference in yttria content of Mono1, Mono2, and Multi1. However, in Multi2, containing 3Y-TZP and 5Y-PSZ, a color change was caused by the use of speed sintering. Therefore, when performing speed sintering with Multi2, it is necessary to select the color in consideration of these results or take measures for staining.

Comparative analysis of various temporary computer-aided design/computer-aided manufacturing polymethyl methacrylate crown materials based on color stability, flexural strength, and surface roughness: An in vitro study.

With recent advancements in digital dentistry, computer-aided design/computer-aided manufacturing (CAD/CAM) processed prostheses have been in very much use recently. This study aims to assess and compare the properties of these materials to better enable the practitioners to select the type of materials for use in a normal clinical practice. This research study was commenced after the approval by our Institutional Review Board (IHEC/SDC/PROSTHO/21/119). Twelve specimens of each group (group 1: CAD/CAM milled prostheses and group 2: three-dimensional (3D) printed prostheses using rapid prototyping) were prepared using the ISO standardization 10477:2004. The flexural strength of the samples that were prepared was tested using a universal testing machine and the values obtained were evaluated. Other samples (ISO standardized) were collected for evaluation of color changes postaging and surface roughness of both groups. Unpaired t-test to analyze flexural strength and surface roughness and Paired t-test was used to statistically analyze the values obtained for color stability. Group 1 showed significantly higher flexural strength and significantly better color stability when the samples were subjected to thermocycling. The mean strength obtained for 3D printed polymethyl methacrylate (PMMA) was 80.06MPa, whereas the mean flexural strength recorded for milled PMMA was 128.32 MPa. There was not much difference observed in the surface roughness of both groups. CAD/CAM milled specimens presented with better color stability and strength when compared to 3D printed specimens. Practitioners should be cautious while using three-dimensionally printed temporary prostheses in the posterior tooth region.

Comparison of the marginal accuracy of metal copings fabricated by 3D-printed resin and milled polymethyl methacrylate - An in vitro study.

Computer-aided design/computer-aided manufacturing (CAD/CAM) systems have gained popularity over the traditional laboratory procedures in dentistry. In the conventional metal casting technique by burnout of a pattern, instead of using a wax pattern (which has several disadvantages), milled polymethyl methacrylate (PMMA) and 3D-printed resin patterns can also be used. The objective of the study was to assess and compare the marginal accuracy of single-crown cobalt-chromium (Co-Cr) metal copings fabricated using milled PMMA and 3D-printed resin patterns. Digital designing was done for metal coping on a prepared typodont mandibular molar using 3Shape Dental Design software. Standard Tessellation Language document of CAD design was used to fabricate 3D-printed resin patterns (Sprintray 3D printer) and milled PMMA patterns (CAD/CAM milling machine CoriTEC). A total of ten Co-Cr copings were casted, of which five belonged to Group A: 3D-printed resin and the other five to Group B: milled PMMA. The copings were assessed for marginal fit at eight different points using a stereomicroscope. Statistical analysis was done using an independent t-test. The t-test revealed a significant difference between the mean marginal gap values of the two groups, with the marginal gap values for the 3D-printed resin group (82.21 ± 15.26 μm) being lesser than that of the milled PMMA group (106.75 ± 12.76 μm). The marginal accuracy of copings fabricated using 3D-printed resin patterns was superior to that of copings fabricated from milled PMMA patterns.

Vertical Marginal Discrepancy Performance of a CAD-CAM System with Multiple Users.

The purpose of this evaluation was to evaluate the vertical marginal discrepancies of a computer-aided design-computer-aided manufacture (CAD-CAM) system used by different providers at separate time intervals. Lithium disilicate monolithic crowns on mandibular third molars were fabricated by three different providers inexperienced in digital dentistry. Using a precision rotary stage mounted on a digital recording microscope, the crown vertical marginal discrepancy was assessed using 160× magnification at 5-degree intervals around the crown marginal circumference for a total of 72 measurements per specimen. In addition to mean vertical marginal discrepancy, the maximum vertical marginal discrepancy, and its location as well as the percent of closed marginal assessments, were assessed. Mean data was analyzed using Kruskal-Wallis and Dunn post hoc testing at a 95% level of confidence (α=0.05). The mean marginal vertical discrepancy for all specimens was 21.1 ± 5.5 μm and a significant difference (p=0.0016) existed between groups but with noted wide similarity overlap. No difference (p=0.65) was observed with the mean closed margin percentage, but a significant difference (p=0.0012) existed in the observed maximum marginal discrepancy between groups. The 2-mm axial wall height (AWH), 20-degree total occlusal convergence (TOC) had significantly less (p<0.017) mean vertical marginal discrepancies than the 4-mm AWH, 20-degree TOC, and the 3-mm AWH, 16-degree TOC groups with the remaining groups similar (p>0.147). The plotted location of the specimen's maximum vertical discrepancy suggests a potential pattern amid the 360-degree margin circumference. Under the conditions of this study, CAD-CAM-derived monolithic lithium disilicate ceramic crowns fabricated by different clinicians demonstrated mean vertical marginal discrepancy results that were less than the suggested maximum clinically acceptable values. A potential for patterns of marginal discrepancy results was identified and deserves further evaluation. Results should be interpreted with caution as in vitro methodologies vary and do not directly correlate with clinical conditions.

The Effect of Smoking and Brushing on the Color Stability and Stainability of Different CAD/CAM Restorative Materials.

This study aimed to investigate and compare the color stability and stainability of computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials in their glazed (G) and polished (P) state when exposed to cigarette smoke, as well as after brushing. Three CAD/CAM restorative materials were investigated: lithium disilicate CAD (LD), zirconia (Zr), and Telio PMMA CAD (PMMA), according to their surface finishing and assignment to cigarette smoking exposure or soaking in the saliva (control) group. The color change (∆E) was calculated before and after the intervention performed for all specimens, using the L*a*b values to quantitatively assess the shade differences. Statistical analysis was performed using one-way repeated measures ANOVA and Bonferroni multiple comparison analysis (α = 0.05). The surface finishing did not influence the materials’ stainability. Color change was noted after smoking, LD and Zr-G and Zr-P had a comparable color change (p > 0.05), while PMMA presented lower ∆E values (p < 0.05). After brushing, all specimens had a significant color change that was high for LD-G and LD-P, and Zr-G, compared with Zr-P and PMMA (p < 0.05). In conclusion, the exposure to cigarette smoke showed that LD, Zr, and PMMA are all susceptible to staining, but brushing decreases surface staining.

Spectrophotometric Evaluation of Translucency of Various Commercially Available Zirconium Oxide Ceramic Systems: An In Vitro Study

To evaluate and compare the translucency of various commercially available zirconium oxide ceramic systems, i.e., Ceramill® Zolid Classic, Ceramill® Zi, and DD Bio ZX²71 by using a dual beam UV-visible spectrophotometer. The present study comprised of 21 disk-shaped samples of zirconia for every group, i.e., group I-Ceramill® Zolid Classic, group II-Ceramill Zi®, and group III-DD Bio ZX²71. Furthermore, each group was split into three subgroups and every subgroup had seven samples each one of 0.7, 0.8, and 0.9 mm thickness. The samples were prepared by computer-aided design/computer-aided manufacturing (CAD/CAM) system devised by Amann Girrbach AG in accord with the steps provided by the manufacturer. The entire sample was designed having 10 mm in diameter with 0.7, 0.8, and 0.9 mm thickness for every group. The UV-visible dual beam spectrophotometer equipped with D2 lamp and W lamp was used for the measurement of absorbance and transmittance in order to assess the translucency of the fabricated zirconia samples. The mean value of transmittance % for Ceramill® Zi at 0.8 mm came out to be 0.849 ± 0.024, i.e., the least among all, whereas the mean value of Ceramill® Zolid Classic was 1.408 ± 0.033, being the highest for the same thickness. DD Bio ZX²71 had an intermediate value of 1.274 ± 0.012. The mean value of absorbance for Ceramill® Zi at 0.8 mm came out to be 2.086 ± 0.013, i.e., the maximum among all, whereas the mean value of Ceramill® Zolid Classic was, being the lowest for the same thickness. DD Bio ZX²71 had an intermediate value of 1.902 ± 0.004. The present study data suggest that all the materials subjected to evaluation exhibited a substantial translucency. We attempted to study few of the desirable properties, these materials should possess when used for prosthetic rehabilitation with esthetic contentment a clinical setup. There has been an ambiguous distinction that Ceramill® Zi Zirconia supersedes the Ceramill® Zolid Classic and DD Bio ZX²71. Furthermore, 0.8 mm thickness substantiates to be the most ideal among 0.7, 0.8, and 0.9 mm. The desired outcome of the procedure becomes dependent solely on the clinician's judgment to opt for the material whose properties are most fitting as per the demands of the esthetics. While a clinician should always be ambitious, but a good clinician should also bear in mind that the success of any treatment procedure not only depends on the assortment of properties of these materials but also the host response and satisfaction evoked by these materials.

Electrical Properties of Two Types of Lithium-Based Glass Ceramics.

The dental ceramic materials are constantly being developed due to their continuous clinical application in the field of esthetic dentistry. Glass ceramics (GC) materials are also of special interest for dental application due to their specific properties; and thus, they can be applied as crowns, veneers and small bridges. However, due to a variety of different GC materials, it is of keen interest to inspect their morphology and ion-diffusion, which also governs aging properties. In this study, two different GC materials were processed, i.e., lithium silicate (LS-10) and lithium disilicate (LS-20). The aforementioned properties can be inspected by using impedance spectroscopy (IS) and scanning electron microscopy (SEM). SEM study suggested that LS-10 material is harder to mechanically process by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Furthermore, IS measurements showed that LS-20 (vs. LS-10) has more pronounced resistance properties. According to IS data, it was concluded that LS-20 (vs. LS-10) has more pronounced resistance properties that point out to hindered ion-diffusion and to better aging properties.

Biocompatibility and Surface Roughness of Different Sustainable Dental Composite Blocks: Comprehensive In Vitro Study.

The study purposed to investigate the biocompatibility and sustainability of two computer-aided design/computer-aided manufacturing (CAD/CAM) resin-based composites compared to a resin-modified ceramic in terms of surface roughness, biofilm formation, cytotoxicity, genotoxicity, and cellular changes observed under transmission electron microscopy (TEM). Three CAD/CAM blocks were used, two resin-based composites [Brilliant Crios (BC) and Cerasmart, (CS) and one hybrid ceramic (Vita Enamic (EN)]. Each block was sectioned into 10 × 12 × 2 mm specimens, followed by finishing and polishing. Each specimen was evaluated for surface roughness using 3D optical profilometry and scanned by scanning electron microscopy. Biofilm formation and its relation to surface roughness have been investigated for all tested materials. A Hep-2 cell line was used to investigate the viability through MTT assay. The cytotoxicity of the materials was measured at 24, 48, and 168 h. The activity of P53, caspase 3, and cytochrome C was evaluated to detect the genotoxicity of different groups, followed by TEM tracking of the cellular changes. Statistical analysis was implemented by utilizing a one-way analysis of variance test. The significance was set at P ≤ 0.05. With regard to the surface roughness, no statistically significant differences were shown between groups. BC possessed the highest biofilm formation value, followed by EN and CS, with no significance between them. No correlation between surface roughness of tested materials and biofilm formation was shown. Considering viability, the highest values were recorded for EN, whereas BC showed the lowest values. P53-fold changes in EN were significantly the lowest, indicating less genotoxicity. Within the current study’s limitations, BC showed the highest biofilm formation. However, no significant surface roughness difference or correlation with biofilm formation was observed in tested materials. EN showed the lowest cytotoxicity and the highest viability. EN revealed the best compatibility performance among tested materials. On the contrary, the BC exhibited fewer preferences.

Compressive strength evaluation of thin occlusal veneers from different CAD/CAM materials, before and after acidic saliva exposure

In the present study are depicted valuable observations for practitioners, obtained from an in vitro study which aims to evaluate the compressive strength of occlusal veneers fabricated from 3 type of restorative materials, before and after 1 month of acidic artificial saliva exposure (pH = 2.939). In this context, 90 extracted human molars were prepared to receive computer-aided design/computer-aided manufacturing (CAD/CAM) occlusal veneers. The restorative materials considered in this study were: Cerasmart; Straumann Nice and Tetric CAD. The occlusal veneers were designed, milled and cemented with an adhesive dual-cure resin cement. From all the extracted human molars, only sixty specimens were immersed in acidic artificial saliva, for 1 month, at 37 °C ± 1 °C and part of this specimens were also thermo-cycled, between 5 and 55 °C ± 2 °C, before compressive strength test. The results showed a lower compressive strength for both the samples exposed to acidic artificial saliva as well as for the samples exposed to acidic artificial saliva and thermo-cycled. Scanning electron microscopy (SEM) showed that after compressive strength, all the specimens non-exposed to acidic artificial saliva, present extensive cracks formation at the surface of the restorations, and after exposure to acidic artificial saliva for 1 month, the surface damage was characterized by longitudinal and profound fractures of the restoration, as well as the fracture of the tooth structure. Between CAD/CAM materials tested, nanoceramic resin shows more favorable fracture patterns, both before and after acidic artificial saliva exposure.

A Novel Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) 3D Printing Method for Nasal Framework Reconstruction Using Microvascular Free Flaps.

The need for a total or subtotal nose resection represents a dramatic situation for any patient and a challenge for the reconstructive surgeon. Because even in the most skillful hands, an optimal result may be difficult to achieve. In this way, sometimes a free flap reconstruction is needed. A subtotal nasal reconstruction is presented using a fasciocutaneous free flap supported by computer-aided design (CAD), computer-aided manufacturing (CAM), and novel 3D printed guide to recreate the nasal cartilage framework. A successfully free flap reconstruction of the nasal framework was achieved supported by the CAD/CAM 3D printed template. We present a novel approach for nasal total or subtotal reconstruction using a CAD/CAM 3D printed model to create the nasal framework, based on the anatomical and radiological evaluation of the patient.

ACCURACY OF REMOVABLE PARTIAL DENTURE METAL FRAMEWORKS FABRICATED BY COMPUTER-AIDED DESIGN/ COMPUTER-AIDED MANUFACTURING METHOD: A SYSTEMATIC REVIEW AND META-ANALYSIS.

This systematic review and meta-analysis aimed to investigate the accuracy of removable partial denture (RPD) frameworks fabricated by computer-aided design/ computer-aided manufacturing (CAD/CAM) systems compared to frameworks produced by conventional casting methods. A systematic literature search was conducted in electronic databases following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, using formulated Boolean operator for searching articles evaluating the fit accuracy of CAD/CAM-fabricated RPD metal frameworks. The agreement of data collection among the reviewers was confirmed using the Cohen kappa coefficient. The modified methodological index for non-randomized studies (MINORS) scale was used to assess the quality of the included studies. Heterogeneity among studies was evaluated, and meta-analyses with global and subgroup analyses were performed. A total of 208 articles were identified with 18 articles available for the narrative review and 7 studies available for meta-analysis on the 3D-printed frameworks for RPD (the overall Cohen kappa coefficient = 0.944). There was no article on the accuracy of RPD frameworks made by milling method. The meta-analysis revealed that the misfit of frameworks obtained with the CAD/CAM method was significantly higher than that of the conventional lost wax and casting method (SMD = 1.23 μm, 95% CI = 0.3610-2.0981 μm, z = 2.77, P = .0055). Regarding the CAD/CAM techniques used for fabricating RPD metal frameworks, the within subgroup analysis showed that the CAD/CAM-based indirect fabrication method produced frameworks with fit accuracy more similar to the conventional lost-wax and casting method (SMD = 1.15 μm, 95% CI = - 0.06136-2.9192 μm, z = 1.28, P < .01) than the CAD/CAM-based direct fabrication method (SMD = 1.35 μm, 95% CI = -0.2722-2.4381 μm, z = 2.45, P < .01), even though there was no statistical difference between the techniques (P = .8482). The fit accuracy of RPD metal frameworks fabricated by the CAD/CAM method was lower than that of frameworks fabricated by the conventional casting method, but it was within the clinically acceptable range in dimensional misfit. The indirect metal 3D printing technique based on pattern printing and subsequent casting produced frameworks with fit accuracy more similar to the conventional method than the direct fabrication technique.

Modern Digital Pediatric Dentistry with the Advent of Intraoral Sensors, Computer-Aided Design/Computer-Aided Manufacturing, and Three-dimensional Printing Technologies: A Comprehensive Review

The conventional methods of fabrication of the dental prosthesis/appliances in pediatric dental patients pose many challenges such as prolonged and multiple appointments, discrepancy in the accuracy of the fit of prosthesis, and cumbersome dental laboratory procedures. The conventional impression-making procedures in young children are regarded as quite cumbersome and difficult due to several clinical factors in dentistry. In recent years, digital Intra-Oral Sensors (IOS), three-dimensional printing (3D-printing) technology and computer-aided design/computer-aided manufacturing (CAD-CAM) technology have been described in existing literature related to different aspects of pediatric dentistry. The aim of the current study was to review the literature related to recent innovative applications of IOS, CAD-CAM, and 3D-printing technology in modern pediatric dentistry. Pediatric dental procedures involving the modern digital technologies such as IOS, CAD-CAM, and 3D-printing in the applications for the digital impression procedure and the fabrication of various types of dental appliances have the good potential to deliver optimum oral-health care in children. Furthermore, it can help in motivating the children and also in instilling the positive attitude and behavior toward dentistry.

Integrating maxillary dentition and 3D facial photo using a modified CAD/CAM facebow

BackgroundAccurate integration of the dentitions with the face is essential in dental clinical practice. Here we introduce a noninvasive and efficient protocol to integrate the digitized maxillary dentition with the three-dimensional (3D) facial photo using a prefabricated modified computer-aided design/computer-aided manufacture (CAD/CAM) facebow.MethodsTo integrate the maxillary dentition with the 3D facial photo, the CAD/CAM facebow protocol was applied to 20 patients by taking a series of 3D facial photos in the clinic and integrating them in the laboratory. The integration accuracy of this protocol was compared with that of a valid 3D computed tomography (CT)-aided protocol concerning translational deviations of the landmarks representing maxillary incisors and maxillary first molars as well as the rotational deviation of the maxillary dentition. The intra- and inter-observer reproducibility was assessed, and the time of clinical operation and laboratory integration was recorded.ResultsThis facebow-aided protocol generated 3D fused images with colored faces and high-resolution dentitions, and showed high reproducibility. Compared with the well-established CT-aided protocol, the translational deviations ranged from 0 to 1.196 mm, with mean values ranging from 0.134 to 0.444 mm, and a relatively high integration error was found in the vertical dimension (Z) with a mean ± standard deviation (SD) of 0.379 ± 0.282 mm. Meanwhile, the rotational deviations ranged from 0.020 to 0.930°, with mean values less than 1°, and the most evident deviation was seen in pitch rotation with a mean ± SD of 0.445 ± 0.262°. The workflow took 4.34 ± 0.19 min (mins) for clinical operation and 11.23 ± 0.29 min for laboratory integration.ConclusionThe present radiation-free protocol with the modified CAD/CAM facebow provided accurate and reproducible transfer of the digitized maxillary dentition to the 3D facial photo with high efficiency.

Digital Volumetric Analysis of CAD/CAM Polymeric Materials after Tooth Brushing.

The objective of the study was to evaluate the volumetric wear of four composite materials for CAD/CAM (computer-aided design/computer-aided manufacturing) systems. The materials evaluated were: Cerasmart (CER), Shofu Block HC (SBH), Tetric CAD (TEC) and Brava (BRA). All the samples (n = 40) were subjected to simulated brushing (100,000 cycles). Wear was evaluated by superimposing pre-and post-brushing scans obtained with an intraoral optical scanner (CEREC Primescan; Dentsply Sirona, Germany), which were subsequently imported into the OraCheck software 5.0 (Dentsply Sirona, Germany). The data were analyzed by ANOVA test and Tukey’s HSD test was used for multiple comparisons. Cerasmart showed the least wear after brushing. All the tested materials exhibited mass loss.

Effect of the thickness of CAD-CAM materials on the shear bond strength of light-polymerized resin cement.

This study aimed to investigate the effect of the thickness of computer aided design-computer aided manufacturing (CAD-CAM) restorative materials on the bond strength of light-polymerized resin cement. Ninety specimens were prepared from three different CAD-CAM materials (a leucite-based glass-ceramic [Empress CAD], a polymer-infiltrated ceramic network [Vita Enamic], and a zirconia-reinforced lithium silicate glass-ceramic [Vita Suprinity]) in different thicknesses (1, 2, and 3mm). One surface of each specimen was treated by using a single-step self-etching ceramic primer (Monobond Etch & Prime). Light-polymerized resin cement was bonded to treated surfaces by exposure to a light-emitting diode curing unit from the untreated side of the samples. Shear bond strength (SBS) between the ceramic and the resin cement was measured by using a universal testing machine. The leucite-based glass-ceramic had higher SBS values than the other materials at each thickness. For each material, 1mm-thick specimens had the highest SBS values. The difference between the SBS values of 2mm- and 3mm-thick polymer-infiltrated ceramic network was nonsignificant, whereas the SBS values of 2mm-thick leucite-based glass-ceramic and the zirconia-reinforced lithium silicate glass-ceramic were significantly higher than those of the corresponding 3mm-thick specimens. The choice of the material and its thickness may be highly important for clinical success when light-polymerized resin cements are used for cementation.

A 3-Year Clinical Evaluation of Endodontically Treated Posterior Teeth Restored with Resin Nanoceramic Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM)-Fabricated Partial Crowns.

BackgroundWe aimed to investigate the clinical effects of resin nanoceramic (RNC) computer-aided design/computer-aided manufacture (CAD/CAM) partial crowns on posterior teeth after root canal treatment over a 3-year period.Material/MethodsA total of 132 posterior teeth restored with CAD/CAM partial crowns were placed in 128 patients. The observation group (n=66) was restored with RNC restorations, while the control group received lithium disilicate-based glass ceramic (LDGC) CAD restorations. Using Fédération dentaire internationale (FDI) World Dental Federation clinical criteria, 2 calibrated evaluators examined the performance of the restorations at baseline, 6, 12, 18, 24, and 36 months. The Kaplan-Meier method and the log-rank test were adopted to analyze the survival rate. The influence of potential risk factors on the main pattern of failure was studied by univariate Cox regression analysis (α=0.05).ResultsAt the 3-year followup, the survival rate of the partial crowns was 83.1% in the RNC group, and 93.5% in the LDGC group (P=0.061). Failures were caused by debonding (66.7%), restoration fracture (26.6%), and tooth fracture (6.7%). No significant differences were found between the 2 materials at 36 months, except for the parameters of “surface luster” (P=0.002) and “occlusal contour and wear” (P=0.009). The RNC group was significantly more likely to debond than the LDGC group (hazard ratio=9.22 [1.17,72.74], P=0.01).ConclusionsRNC CAD/CAM-fabricated partial crowns are a potential clinical alternative for endodontically treated posterior teeth, with a survival rate of 83.1% at the 3-year followup. The main pattern of failure was debonding, which might be influenced by surface pretreatment of the RNC material.

Surface Characterization of Current Dental Ceramics Using Scanning Electron Microscopic and Atomic Force Microscopic Techniques

Dental ceramics is a highly esthetic material and its surface properties can impact its roughness, bonding properties, as well as strength and wear. The aim of the study is to analyze the surface characteristics by the determination of the roughness parameters of three dental ceramics used in computer-aided design/computer-aided manufacturing (CAD/CAM) technique: lithium disilicate (LS2), zirconium oxide-reinforced lithium silicate (ZLS), and zirconium oxide (ZrO2), prepared using two different processing techniques, polishing (self-glaze) and glazing with three different glazes. Both glass ceramics, pre-crystallized LS2 and crystallized ZLS, were cut into disks, and the surface was ground and polished. Crystallization was performed for LS2 samples, while ZrO2 samples were fabricated using CAD/CAM and sintered. Then, the glaze was applied and the samples were reheated as per the manufacturer’s instructions. The contact surface topographies of the tested ceramics were measured by atomic force microscopy (AFM) and the roughness parameters: average surface roughness (Ra), root-mean-square roughness (Rq), and surface area difference (SAD) were evaluated. Changes in the morphological characteristics of the tested ceramics were examined by scanning electron microscopy (SEM), and the surface chemical composition was determined by attenuated total reflection Fourier-transform infrared spectroscopy (FT—IR). In the spectroscopic analysis, a characteristic signal for ZrO2 was obtained for ZLS samples. A significant decrease in surface roughness was observed after glazing in all tested ceramics (p &lt; 0.05). The abstract should be an objective representation of the article and it must not contain results that are not presented and substantiated in the main text and should not exaggerate the main conclusions.

Effect of decontamination materials on bond strength of saliva-contaminated CAD/CAM resin block and dentin.

The aim of this study was to evaluate the effect of decontamination agents against saliva contamination on the bonding of computer-aided design/computer-aided manufacturing (CAD/CAM) resin block. Three commercially available decontamination agents were used in this study. The samples were subjected to microtensile bond strength test. A saliva protein staining test was performed by the pigment binding method to investigate the effect of removing saliva protein. All the decontamination agents could significantly restore the bond strength from the saliva contamination, and KATANA Cleaner showed no significant difference with the control. From the results of the saliva protein staining test, KATANA Cleaner showed higher removal effect of saliva protein for CAD/CAM resin block surface than the other materials due to the surface active effect of MDP salt. It was suggested that cleaners containing MDP salt were more effective in removing artificial saliva contamination than cleaners containing other ingredients for CAD/CAM resin blocks.

Present and Future Impacts of Computer-Aided Design/ Computer-Aided Manufacturing (CAD/CAM)

The world is a growing place with great technological advancement in all areas of life. For some decades now, various disciplines and industries have been engaged in using Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) across different nations. CAD/CAM utilizes computers to integrate design and manufacturing processes for quality product attainment. This review article examined the present impacts of CAD/CAM on some sectors such as architecture, manufacturing, engineering and design, electronics, automobile, shipbuilding, aerospace, and medicine. Highlights on some applications and future impacts of CAD/CAM have also been discussed. The numerous impacts of CAD/CAM are discussed in the study. It was concluded that CAD/CAM had become integral parts of our world to ease production against traditional methods. The study recommended more research focus on biomaterials for 3-D bioprinting for tissue engineering applications.

Evaluation of The Processing Discrepancies Between Dental and Nondental CAD Software Using The Smoothing Design Tool

Statement of the problem: The advancing computer-aided design/com-puter-aided manufacturing (CAD/CAM) technology has changed the fabrica-tion protocols of fixed prosthodontic restorations dramatically in the last 25 ye-ars. Beside the dental CAD programs open source nondental software have been utilized for prosthodontic purposes. Despite the progress in technology, varying accuracy and precision rates, and lack of standardized workflows are still challenging issues. Objective: No study to the authors' knowledge evaluated the precision of the manually used processing tools of CAD softwares despite the necessity of utilizing multiple tools to design a restoration, thus it was aimed to evaluate the processing discrepancies of smoothing procedures. Materials &amp; Methods: A virtual working cast of a maxilla with six teeth prepared with shoulder finish lines containing irregularities up to 50μm were composed. The irregularities were smoothed manually using the 'brush' tools in the 'sculpt' mode of the DWOS, Blender and Meshmixer softwares. Smoothed virtual working casts were superimposed with the reference virtual working cast. Results: The results of Tukey HSD test revealed significant differences between Meshmixer and Blender (P=0.000), and Meshmixer and DWOS (P=0.000), no significance was found between DWOS and Blender values (P=0.987). Conclusion: The results of the study pointed out that smoothing proce-dure may lead to significant differences in discrepancy values, nondental CAD software can perform smoothing with less discrepancy thus, commencing furt-her studies including multiple users and softwares for the evaluation of diffe-rent design tools seems imperative.