Color stability of precolored and extrinsically colored monolithic multilayered polychromatic zirconia: Effects of surface finishing and aging.

PURPOSE: To explore the impact of zirconia types, coloring methods, and surface finishing on the color stability of monolithic multilayered polychromatic zirconia after artificial aging, including thermocycling and simulated toothbrushing. MATERIALS AND METHODS: Eighty square-shaped zirconia samples were divided into 2 types (M3Y-TZP and M6Y-PSZ), further categorized based on coloring methods (precolored and extrinsically colored) and surface finishing techniques (mechanical polishing or glazing). The color stability was assessed using the CIEDE2000 formula. Artificial aging was simulated via thermocycling and toothbrushing. All samples were analyzed with a spectrophotometer to determine the post-aging color changes (ΔE00). The ΔE00 were interpreted and classified using the 50:50% perceptibility threshold (PT) and the 50:50% acceptability threshold (AT). Comparisons between groups for ΔE00 differences were performed using three-way ANOVA, with pairwise comparisons facilitated by Fisher's protected least significant difference test, α = 0.05. RESULTS: The study results indicated significant impacts of zirconia type, coloring method, and surface finishing on color stability. The M6Y groups experienced significantly greater color changes (6.61 ± 1.63) compared to the M3Y groups (3.40 ± 2.24), p < 0.0001. For both types of zirconia, extrinsically colored samples exhibited significantly higher ΔE00 when mechanically polished (p = 0.004). However, surface finishing had no significant effect on ΔE00 in precolored samples of either zirconia material (p = 1.000). The evaluation and categorization of ΔE00 variations indicated that nearly all color changes in the M6Y groups, regardless of being precolored, extrinsically colored, polished, or glazed, were deemed extremely unacceptable (Grade 1). In contrast, the M3Y groups showed more acceptable results, with the majority of color changes classified as moderately unacceptable (Grade 3). CONCLUSIONS: The color stability of multilayered polychromatic zirconia is influenced by the type of material, extrinsic coloring, and the chosen surface treatment post-artificial aging. The translucent 6Y-PSZ exhibited lower color stability, especially with only mechanical polishing. For the fabrication of M3Y-TZP and 6Y-PSZ monolithic multilayered polychromatic zirconia restorations, extrinsic coloring should be paired with glazing to maintain color stability. Conversely, in the absence of extrinsic coloring, both glazing and mechanical polishing are effective in preserving color stability.

Color stability of CAD-CAM hybrid ceramic materials following immersion in artificial saliva and wine.

PURPOSE: To examine the color stability of 3D-printed and milled, interim, and definitive, restorative materials after immersion in artificial saliva and wine for 1, 3, and 6 months. MATERIAL AND METHODS: The study used a 2 × 5 factorial design with 10 subgroups, including 2 immersion liquids (artificial saliva and wine) and 5 manufacturing technology and restorative material combinations (n = 10). Color measurements were taken using a contact-type digital spectrophotometer (CM-2600d Spectrophotometer; Konica Minolta Healthcare Americas Inc) before immersion and at 1 month (T1), 3 months (T3), and 6 months (T6) after immersion. The CIE2000 system was used to calculate quantitative measurements of color differences in ΔE00, and comparisons were made to the acceptability threshold (AT) and perceptibility threshold (PT). Repeated measures of ANOVA (α = 0.05) were used to compare differences in color changes between manufacturing technology/restorative material-immersion liquid combinations at T1, T3, and T6. RESULTS: To compare the effect of immersion liquid and time on the manufacturing technology/restorative material groups, the ΔE00 values were compared to the PT of 0.8 and the AT of 1.8. Wine caused significant color changes in ΔE00 values beyond the PT and AT values in all groups at all time intervals, except for the AT value of milled definitive crowns (hybrid nano-ceramic material). Wine immersion caused significant ΔE00 for all manufacturing technology/restorative material groups at all time intervals (1 month, 3 months, and 6 months) when compared to artificial saliva immersion (all p < 0.001). CONCLUSION: Upon exposure to artificial saliva, 80%-100% of samples from all groups remained within the acceptable and perceptible color change thresholds. The wine had significant chromogenic effects on all tested restorative materials, however, the milled definitive crowns (hybrid nano-ceramic material) showed the greatest color stability. For patients with heavy wine consumption, 3D-printed definitive crowns (hybrid ceramic-filled material) may show discoloration exceeding acceptable and perceptible color change limits.

The 3D-printed shell complete denture technique: Simplifying prosthodontic diagnosis prior to implant planning.

Traditionally, artificial teeth arrangements or the definitive complete dentures are used to establish important prosthodontic parameters such as the occlusal plane orientation, vertical dimension, and the incisal edge position. The relationship of these elements with the underlying bony structures is commonly evaluated using advanced planning protocols such as the dual scan technique. This technique article presents an uncomplicated alternative approach to establish these parameters intraorally using a 3D-printed shell complete denture generated from a 3D scan of the patient's existing complete denture.

Influence of exposure protocol, voxel size, and artifact removal algorithm on the trueness of segmentation utilizing an artificial-intelligence-based system.

PURPOSE: To evaluate the effects of exposure protocol, voxel sizes, and artifact removal algorithms on the trueness of segmentation in various mandible regions using an artificial intelligence (AI)-based system. MATERIALS AND METHODS: Eleven dry human mandibles were scanned using a cone beam computed tomography (CBCT) scanner under differing exposure protocols (standard and ultra-low), voxel sizes (0.15 mm, 0.3 mm, and 0.45 mm), and with or without artifact removal algorithm. The resulting datasets were segmented using an AI-based system, exported as 3D models, and compared to reference files derived from a white-light laboratory scanner. Deviation measurement was performed using a computer-aided design (CAD) program and recorded as root mean square (RMS). The RMS values were used as a representation of the trueness of the AI-segmented 3D models. A 4-way ANOVA was used to assess the impact of voxel size, exposure protocol, artifact removal algorithm, and location on RMS values (α = 0.05). RESULTS: Significant effects were found with voxel size (p < 0.001) and location (p < 0.001), but not with exposure protocol (p = 0.259) or artifact removal algorithm (p = 0.752). Standard exposure groups had significantly lower RMS values than the ultra-low exposure groups in the mandible body with 0.3 mm (p = 0.014) or 0.45 mm (p < 0.001) voxel sizes, the symphysis with a 0.45 mm voxel size (p = 0.011), and the whole mandible with a 0.45 mm voxel size (p = 0.001). Exposure protocol did not affect RMS values at teeth and alveolar bone (p = 0.544), mandible angles (p = 0.380), condyles (p = 0.114), and coronoids (p = 0.806) locations. CONCLUSION: This study informs optimal exposure protocol and voxel size choices in CBCT imaging for true AI-based automatic segmentation with minimal radiation. The artifact removal algorithm did not influence the trueness of AI segmentation. When using an ultra-low exposure protocol to minimize patient radiation exposure in AI segmentations, a voxel size of 0.15 mm is recommended, while a voxel size of 0.45 mm should be avoided.

The Accuracy of Guided Implant Surgery With Different Fields of View of Cone-Beam Computerized Tomography.

Although a smaller size field of view (FOV) of cone-beam computerized tomography (CBCT) reduces radiation exposure, its effect on the accuracy of static computer-aided implant surgery (s-CAIS) remains unknown. This study aimed to evaluate the impact of the size of FOV on the accuracy of s-CAIS and to investigate if the arch affects this effect. A total of 32 implant sites on 8 identical scannable models (maxillae and mandibles) were randomly allocated to 2 FOV sizes: test (5 × 5 cm) and control (10 × 10 cm). All models were scanned with an intraoral scanner (IOS). With the registration of the surface scan and CBCT image, a prosthetic-driven implant position was planned. Following the fabrication of surgical templates, a single-blinded surgeon placed all implants with the fully guided s-CAIS protocol. IOS captured the implant positions with the scan body attached. Implant-planning software measured the angular deviation, 3-dimensional (3D) deviation at the crest, and 3D deviation at the apex between preplanned and actual implant positions. Two-way analysis of variance was used to analyze the effect of FOV and arch on the deviations. The size of FOV did not show a significant effect (P > .198) on angular deviation, 3D deviation at the crest, or 3D deviation at the apex. No significant difference was found when comparing the effect of the size of FOV between the maxillary and mandibular implants. In conclusion, the use of small FOV CBCT demonstrated comparable accuracy of s-CAIS to the use of medium FOV CBCT.

Comparison of surface characteristics of denture base resin materials with two surface treatment protocols and simulated brushing.

PURPOSE: To investigate the effects of 4 denture base materials, 2 surface treatment protocols, and simulated brushing (SB) on the surface hardness, surface roughness, surface gloss, and the surface loss of denture base materials. MATERIALS AND METHODS: Four denture base resin material groups (compression-molded, injection-molded, 3D-printed, and milled) with two different surface treatment protocols (polished and glazed) were utilized in this study. A total of 80 samples (n = 10) were evaluated for surface hardness (Vickers) before SB. SB was performed for each sample (custom-built V8 cross brushing machine, 50,000 reciprocal strokes). Surface roughness (Ra) was measured before and after SB with a non-contact optical profilometer. Surface gloss was performed using a glossmeter to determine changes in surface reflectivity of the specimens before and after SB. Surface loss (wear resistance) was measured after SB using optical profilometry. The effects of material, surface treatment, and SB on all surface characteristics were examined with two-way and three-way analysis of variance models (ANOVA) (α = 0.05). RESULTS: The polished compression-molded group had significantly higher surface hardness than all other groups. The protective glaze coating significantly increased the surface hardness for all groups (P < 0.001). SB increased the surface roughness of all groups regardless of surface treatments (P < 0.001). The increase in surface roughness after SB was significantly higher with polished surface treatment than with a glazed surface treatment in all groups (P < 0.001). Surface gloss was significantly higher with the glazed surface treatment than with the polished surface treatment for all denture base materials (P < 0.001). After SB, milled denture base material showed the highest, and 3D-printed material showed the second highest surface gloss compared to the other groups (P < 0.001), regardless of surface treatment. In all materials tested, surface glaze significantly decreased surface loss (P < 0.001). With the glaze surface treatment, compression-molded denture base material had significantly less surface loss (more surface gain) than other materials, while with the polished surface treatment, 3D-printed denture base material had the least surface loss when compared with other groups. CONCLUSIONS: A single layer of nano-filled, light-polymerizing protective glaze coating has displayed potential for enhancing the longevity of denture base materials, as evidenced by increased hardness and wear resistance. Following simulated brushing, the milled denture material exhibited the highest surface gloss and lowest surface roughness among all groups, regardless of the surface treatment protocol. This indicates that milled denture base material possesses favorable surface properties and may serve as a viable alternative to traditional denture base materials.

Accuracy of digital duplication scanning methods for complete dentures.

PURPOSE: To compare the accuracy of four digital scanning methods in duplicating a complete denture. MATERIAL AND METHODS: Four scanning methods were used: cone beam computed tomography (CBCT), Straumann desktop scanner (DS), Trios intraoral scanner (TIO), and Virtuo Vivo intraoral scanner (VVIO). Each method was used to duplicate all the surfaces of a printed complete denture. The denture was scanned 10 times in each group. The trueness (in root mean square, RMS) and precision (in standard deviation, SD) were calculated by comparing the combined dentition, denture extension, and intaglio surfaces with the reference file. One-way analysis of variance and F-tests were used to test statistical differences (α = 0.05). RESULTS: For the scanning accuracy of the whole denture, CBCT showed the highest RMS (0.249 ± 0.020 mm) and lowest trueness than DS (0.124 ± 0.014 mm p < 0.001), TIO (0.131 ± 0.006 mm p < 0.001), and VVIO (0.227 ± 0.020 mm p = 0.017), while DS and TIO showed smaller RMS than VVIO (p < 0.001). For the trueness of dentition, denture extension, and intaglio surfaces, CBCT also showed the highest mean RMS and lowest trueness among all groups (p < 0.001). DS and TIO had smaller mean RMS and higher trueness among all groups in all surfaces (p < 0.001, except VVIO in intaglio surface, p > 0.05). TIO had significantly lower within-group variability of RMS and highest precision compared to DS (p = 0.013), CBCT (p = 0.001), and VVIO (p < 0.001) in the combined surface. For dentition and denture extension surfaces, TIO showed similar within-group variability of RMS with the DS group (p > 0.05) and lower than CBCT and VVIO (p < 0.001). CONCLUSION: The 7 Series desktop scanner and Trios 4 intraoral scanner can duplicate dentures in higher trueness than CBCT and the Virtuo Vivo intraoral scanner. The Trios 4 intraoral scanner was more precise in the combined surfaces than other scanning methods, while the 7 Series desktop scanner and Trios 4 intraoral scanner were more precise in the denture extension surface.

Performance of the caries diagnosis feature of intraoral scanners and near-infrared imaging technology-A narrative review.

PURPOSE: To describe and discuss the benefits and drawbacks of various dental caries diagnostic techniques, including the use of intraoral scanners for caries diagnosis based on near-infrared imaging (NIR) technology. MATERIAL AND METHODS: A MEDLINE search from 1980-2023 focused on dental caries diagnostic techniques, emphasizing intraoral scanners using NIR technology. Alternative caries detection methods were also evaluated for their advantages and limitations, enabling a comparison with NIR. The review included traditional caries tools, the latest detection methods, and NIR's role in intraoral scanners, drawing from case reports and both in vivo and in vitro studies. Keywords like "caries detection," "intraoral scanners," and "Near Infrared Imaging (NIRI)" guided the search. After screening titles and abstracts for relevance, full texts with valuable insights were thoroughly analyzed. The data was grouped into three: traditional diagnostics, advanced digital methods, and intraoral scanner-based detection. RESULTS: This comprehensive narrative review described and discussed the current state of dental caries diagnostic methods, given the insufficient number of clinical investigations suitable for a systematic review. Traditional caries diagnosis techniques have shown variable accuracy dependent on a dentist's experience and the potential over-removal of healthy tooth structures. Intraoral scanners have emerged as a novel caries detection method, because of their integration of NIR technology. Various studies have confirmed the efficacy of NIR in detecting interproximal caries and in the early diagnosis of non-cavitated caries. Specifically, intraoral scanners have demonstrated promising results, proving comparable to established diagnostic methods like bitewing radiography. Nevertheless, while the integration of NIR into intraoral scanners seems promising, the technology still faces challenges, notably its accuracy in detecting secondary and subgingival cavities. However, with anticipated integrations of AI, NIR in intraoral scanners could revolutionize early caries detection. CONCLUSIONS: Intraoral scanners with NIR technology offer non-destructive imaging, real-time lesion visuals, and enhanced patient communication. Although comparable to bitewing radiography in some studies, a universally accepted diagnostic tool is lacking. Future research should compare them with existing methods, focusing on clinical outcomes, cost-effectiveness, and patient acceptance.

Marginal Fit, Mechanical Properties, and Esthetic Outcomes of CAD/CAM Interim Fixed Dental Prostheses (FDPs): A Systematic Review.

This systematic review aimed to study the outcomes of CAD-CAM (milled and 3D-printed) interim dental prostheses when compared to conventional ones. The focused question of "In natural teeth, what are the outcomes of CAD-CAM interim FDPs compared to the conventionally-manufactured ones regarding marginal fit, mechanical properties, esthetics, and color stability" was formulated. The systematic search was conducted electronically in the PubMed/MEDLINE, CENTRAL, EMBASE, Web of Science, New York Academy of Medicine Grey Literature Report, and Google Scholar databases by using the MeSH keywords and keywords associated with the focused question and limiting articles to those published between 2000 and 2022. A manual search was conducted in selected dental journals. The results were analyzed qualitatively and are presented in table format. Of the included studies, 18 studies were in vitro and 1 was a randomized clinical trial. Of the eight studies analyzing the mechanical properties, five studies favored the milled interim restorations, one study favored both 3D-printed and milled interim restorations, and two studies reported better mechanical properties in conventional interim restorations. Among four studies evaluating the marginal discrepancies, two studies favored the marginal fit in milled interim restorations, one study reported a better marginal fit in both milled and 3D-printed interim restorations, and one study found conventional interim restorations have a better marginal fit and smaller marginal discrepancy when compared to both milled and 3D-printed restorations. Among five studies that evaluated both the mechanical properties and marginal fit, 1 study favored 3D-printed interim restorations and four studies favored milled interim restorations over the conventional ones. Two studies analyzing the esthetics outcomes demonstrated better results with milled interim restorations compared to conventional and 3D-printed interim restorations in terms of their color stabilities. The risk of bias was low for all the studies reviewed. The high level of heterogeneity within the studies excluded meta-analysis. Most of the studies favored the milled interim restorations over the 3D-printed and conventional restorations. The results suggested that milled interim restorations offer a better marginal fit, higher mechanical properties, and better esthetic outcomes in terms of color stabilities.

Tensile bond strength of auto-polymerizing and heat-polymerizing denture reliners on the conventional and CAD-CAM denture base materials.

PURPOSE: The study aimed to compare the tensile bond strength (TBS) of auto-polymerizing and heat-polymerizing denture reliners on the conventional (compression-molding and injection-molding) and computer-aided design and computer-aided manufacturing (milled and 3D-printed) denture base materials. MATERIALS AND METHODS: Eighty standard dogbone-shaped specimens were fabricated from four materials: compression-molding, injection-molding, milled, and 3D-printed denture base materials. A 3-mm cutoff was removed from each specimen at the midsection, and all specimens were reattached with either auto-polymerizing (n = 10) or heat-polymerizing (n = 10) reliner. The TBS was measured on the universal testing machine. A scanning electron microscope (SEM) was used to examine the fractured surfaces at cross sections to determine the dominant failure mode in each group. Two-way ANOVA was used to examine the effects of denture base material and reliner on the TBS (α = 0.05). Weibull survival analysis was also used to determine the survival probability curves. RESULTS: Heat-polymerizing reliner led to a higher TBS than the auto-polymerizing reliner, except in the compression-molding (p = 0.573) groups. Compression-molding denture base material connected with a heat-polymerizing reliner showed the highest TBS (29.8 ± 6.9 MPa), whereas 3D-printed denture base material connected with an auto-polymerizing reliner showed the lowest TBS (7.2 ± 0.9 MPa). The survival probability based on the Weibull model demonstrated that the compression-molding denture base material connected with either auto-polymerizing or heat-polymerizing reliners had the longest survival time to failure, whereas 3D-printed denture base material relined with auto-polymerizing reline material showed the shortest survival time to failure. Under the SEM, the compression-molding groups demonstrated that the failure modes were mixed but predominantly cohesive. The injection-molding and milled groups showed predominantly adhesive failures at the denture base-reline material interfaces. The dominant mode of failure in the 3D-printed groups was cohesive failures within the bonding adhesive. CONCLUSIONS: Although the heat-polymerizing reliner led to a higher TBS than the auto-polymerizing reliner in most denture base materials, the compression-molding denture base material can achieve high TBS with both reliners. When the auto-polymerizing reliner is used with 3D-printed denture base material, clinicians should be aware of lower TBS value and possible cohesive failures, and the detachment of the reliner from the denture base.

The effects of additive manufacturing technologies and finish line designs on the trueness and dimensional stability of 3D-printed dies.

PURPOSE: To evaluate the effects of 5 manufacturing technologies and 2 finish line designs on the trueness and dimensional stability of 3D-printed definitive dies at finish line regions under different storage conditions and time. MATERIAL AND METHODS: Preparation of light chamfer and round shoulder finish lines were adopted individually on two mandibular first molar typodont teeth and digitalized as standard tessellation language (STL) files. A total of 240 samples (192 AM definitive dies and 48 definitive conventional stone dies) in 20 groups (n = 12) were manufactured based on 2 finishing line designs (chamfer and shoulder), 5 manufacturing technologies (4 additively manufactured technologies and conventional stone die), and 2 storage conditions (light exposure and dark). The 4 additively manufactured (AM) technologies include a DLP 3D-printer, an economic LED 3D-printer, a CLIP 3D-printer, and an SLA 3D-printer. All the study samples were distributed into two storage conditions. Subsequently, samples were digitalized to STL files at 3 different time points (within 36 hours, 1-month, and 3-months). A surface matching software was used to superimpose the sample STL files onto the corresponding original STL files with the best-fit alignment function. The trueness of each printed and stone definitive dies and their dimensional stabilities were measured by the root mean square (RMS, in mm). A linear mixed-effects model was used to test the effects of the finish line design, manufacturing technology, storage condition, and storage time on RMS values (α = 0.05). RESULTS: While finish line designs had no significant effects [F(1, 220) = 0.85, p < 0.358], the manufacturing technologies [F(3, 220) = 33.02, p < 0.001], storage condition [F(1, 220) = 4.11, p = 0.044], and storage time F(2, 440) = 10.37, p < 0.001] affected the trueness and dimensional stability of 3D-printed dies at finish line regions. No significant interactions were found among the 4 factors. For the manufacturing technologies, Type IV stone groups and LCD 3D-printer groups had significantly higher RMS values than the other 3 printers (p < 0.001) with no significant differences between Type IV stone and LCD 3D-printer groups (p = 0.577). DLP 3D-printer groups had higher RMS values than both SLA 3D-printer groups and CLIP 3D-printer groups (p < 0.001). There were no significant differences between SLA 3D-printer groups and CLIP 3D-printer groups, p = 0.671. For the effects of storage conditions, RMS values were significantly higher in the groups stored with the direct light exposure than the ones stored in the dark, p = 0.044. In terms of the effects of storage time, the RMS values were significantly higher after 1-month storage, p = 0.002; and 3-month storage, p < 0.001, than the ones at the immediate postmanufacturing stage. However, the RMS values after 1-month and 3-month storage were not significantly different from each other (p = 0.169). CONCLUSIONS: Manufacturing technologies, storage conditions, and storage time significantly affected the trueness and dimensional stability of 3D-printed dies at finish line regions, while finish line designs had no significant effects. Among the AM technologies tested, all have produced either comparable or truer 3D-printed dies than the Type IV dental stone dies, and the CLIP and SLA 3D-printers produced the best outcomes. 3D-printed dies showed significant distortion after 1-month and 3-months storage, especially under light exposure storage conditions. These findings may negate the clinical need to preserve 3D-printed dies, and digital data should be preserved instead.

The Effects of Beverages and Surface Treatments on the Color Stability of 3D-Printed Interim Restorations.

PURPOSE: To evaluate the color stability of 3D-printed interim restorations with different surface treatments while immersed in various staining solutions or beverages (artificial saliva, tea, coffee, and wine) for 6 months. MATERIAL AND METHODS: An acrylic tooth was prepared for an all-ceramic full-coverage restoration. A laboratory scanner was used to digitize the prepared abutment tooth. A virtual all-ceramic full-coverage restoration was designed on the digitized abutment tooth using a laboratory CAD/CAM software. Eighty abutment teeth and interim restorations were 3D-printed with tooth-colored photopolymerizing resin. The restorations were randomly allocated into two different groups: Polish and Optiglaze. For the Polish group, interim restorations were finished and polished with aluminum oxide finishers/polishers. For the Optiglaze group, one layer of nanofilled, light-polymerizing protective coating was then applied. The 80 printed interim crowns were divided into 4 different groups depending on where they would be immersed: Artificial saliva, coffee, wine, and tea. After the sample allocations, there were 8 experimental groups. Each group was allocated with 10 specimens. Color measurements were obtained using a digital spectrophotometer in conjunction with The CIE L*a*b* system before the immersion and 6 months after the immersion. Two-way analysis of variance (ANOVA) was used to test the effects of surface treatment, immersion liquid, and their interaction on ΔE at 6-month post-immersion. Fisher's protected least significant differences (LSD) was used as post hoc test to compare groups differences (α = .05). RESULTS: There were significant effects of surface treatment [F(1,72) = 13.39, p = 0.000], immersion liquid [F(3,72) = 74.18, p = 0.000], and their interaction [F(3,72) = 16.33, p = 0.000] on ΔE at 6-month post-immersion at the α = .05 level. The polish group showed significantly higher ΔE than the Optiglaze group when immersed in coffee (p < 0.001) and wine (p = 0.015). The Optiglaze group showed significantly higher ΔE than the polish group that was immersed in artificial saliva (p < 0.001). The wine group showed higher ΔE than all other immersion liquid groups for both polish and Optiglaze surface treatments (p < 0.001 for all comparisons). ΔL* showed a reduction that was significantly higher than the 2.0 acceptability threshold in the wine-polish (p < 0.001) and wine-Optiglaze (p < 0.001) groups. ΔE showed a color change that was significantly higher than the perceptibility and acceptability thresholds for all the groups under polish surface treatment (p < 0.001). ΔE also showed a color change that was significantly higher than the perceptibility and acceptability thresholds for artificial saliva, tea, and wine under Optiglaze surface treatment (p = 0.004). CONCLUSIONS: 3D-printed interim restorations showed significant discoloration after 6-months immersions in the artificial saliva and common beverages (including tea, coffee, and wine). Among all the chromogenic beverages, red wine caused the most significant discoloration on the interim restorations. When 3D-printed interim restorations are needed for extended intraoral service, nano-filled, light polymerizing protective coating can reduce the restoration discoloration caused by chromogenic beverages. The protective effect is most significant against coffee.

The Trueness of Obturator Prosthesis Base Manufactured by Conventional and 3D Printing Techniques.

PURPOSE: To compare the intaglio surface trueness of obturator prosthesis bases manufactured by traditional compression molding, injection molding, and 3D printing techniques. MATERIALS AND METHODS: A complete edentulous master cast with Aramany Class I maxillary defect was selected for this in vitro study. Four study groups (n = 10/group) were included in this study, Group A: Compression Molding, Group B: Injection Molding, and Group C: Cara Print 3D DLP Printer, and Group D: Carbon 3D DLS Printer. All obturator prostheses' intaglio surfaces were scanned with a laboratory scanner (E4; 3Shape Inc, New Providence, NJ) and the dimensional differences between study samples and their corresponding casts were calculated as the root mean square (measured in mm, absolute value) using a surface matching software (Geomagic design X; 3D Systems, Rock Hill, SC). One-way Analysis of variance (ANOVA) and Fisher's least significant difference (LSD) test were used to compare groups differences in RMS (α = 0.05). RESULTS: There was a significant effect of manufacturing technique on the RMS values for the 4 conditions [F(3,36) = 5.743, p = 0.003]. Injection Molding (0.070 mm) and Compression Molding groups (0.076 mm) had a lower interquartile range, and the Cara Print 3D-Printer group (0.427 mm) and Carbon 3D-Printer (0.149 mm) groups had a higher interquartile range. The Injection Molding group showed the best and uniform surface matching with the most area in green in the color maps. The Injection Molding group (0.139 ± 0.049 mm) had significantly lower RMS than all other groups (p < 0.001 for all comparisons). Compression Molding (0.269 ± 0.057 mm), Cara Print 3D-Printer (0.409 ± 0.270 mm), and Carbon 3D-Printer (0.291 ± 0.082 mm) groups were not significantly different from each other (Compression Molding versus Carbon 3D-Printer, p = 0.59; Compression Molding versus Cara Print 3D-Printer, p = 0.25; Cara Print 3D-Printer versus Carbon 3D-Printer, p = 0.40). CONCLUSION: Obturator prosthesis bases manufactured with injection molding technique showed better intaglio surface trueness than ones made by the compression molding technique and 3D printers. Although obturator prosthesis bases manufactured from different 3D printers showed similar trueness, a DLP 3D printer produced less consistent outcome than a DLS 3D printer.

Using a Digital Dentistry Integrated Planning and Manufacturing Service in Completely Edentulous Treatment.

The use of an integrated digital planning and manufacturing modular service and a time-tested dental implant system to treat a completely edentulous patient, as shown in this case report, offers numerous clinical benefits. Computer-guided surgery and digital dentistry have gained in popularity and demonstrated great clinical success; however, clinicians and dental laboratory technicians can further maximize the benefit gained from these technologies through additional training and resource investment. By using the streamlining solution (Smile in a Box®, Straumann) described in a clinical step-by-step manner in this case report, dental professionals can provide effective digital solutions for improved patient treatment acceptance, experience, and satisfaction.

CAD-CAM cobalt-chromium surgical template for static computer-aided implant surgery: A dental technique.

A digital process for designing and manufacturing a cobalt-chromium (Co-Cr) surgical template for static computer-aided implant surgery (s-CAIS) is described. The use of Co-Cr provides the advantage of a material with improved mechanical properties to reduce the possibility of surgical template fracture during s-CAIS. The stronger material also allows for a thinner surgical template, which in turn allows better access when the interarch operative space is limited or a longer implant is inserted. Limitations of the technique include the need for computer-aided manufacturing technology and, with the use of Co-Cr, a higher overall cost.