This article presents three cases outlining the benefits of utilizing a combination of digital and conventional workflows for the fabrication of immediate complete dentures. This combined digital and conventional approach addresses the recording of denture border extensions, digital articulation, and fabrication of complete dentures.
To investigate the ability of the smart denture conversion (SDC) technique to produce a stronger interim full-arch implant restoration.
Three materials (OnX Tough 3D-printed resin, milled PMMA, and injection molded PMMA) were used to fabricate 180 specimens, 60 specimens per material. Then, an equal number of specimens were assigned a conversion technique: either traditional denture conversion or smart denture conversion. The conversions were performed on a pickup jig containing two multiunit abutment replicas. Acrylic resin was used as the pickup material. After denture conversions were performed, all specimens had uniform dimensions. To evaluate mechanical strength, each specimen underwent a 3-point bend test using an Instron machine with static load testing. Data analysis employed a two-way ANOVA considering material type, method of conversion, and their interaction, with Tukey HSD post hoc tests conducted in STATA 18.0, where significance was set at p < 0.05.
Results from this study are described as method of conversion, material, and the combination of method of conversion and material. The method of conversion was statistically significant for mean fracture strength, resulting in a p-value < 0.037. Choice of material showed statistically significant results for mean fracture strength, with a p-value < 0.000. The combination of method of conversion and material showed a statistically significant result for mean fracture strength with a p-value < 0.000.
Out of 180 specimens, the combination of OnX Tough 3D-printed specimens converted with smart denture conversion yielded the highest mean fracture strength and the highest individual fracture strength value.
Purpose: This in vitro study aims to compare the effects of electrolytic polishing (EP), plasma electrolytic polishing (PP), dry electropolishing (DP), and their combination on the surface characteristics, corrosion resistance, and material reduction of selective laser melting (SLM) printed dental cobalt-chromium (Co-Cr) alloy.
Materials and methods: Standard samples and removable partial denture (RPD) frameworks were SLM-printed and then polished using the following methods: mechanical polishing (MP), EP, PP, DP, PDP (PP + DP), DPP (DP + PP), and PDPP (PP + DP + PP). Surface characteristics were analyzed using optical profilometry, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Corrosion resistance was assessed through electrochemical testing and ion release experiments. The metal reduction was evaluated by measuring weight loss, major connector and clasp thickness loss, and framework adaptation. The post-processing time for the technician's fine polishing of these frameworks was recorded to further evaluate the polishing quality of the frameworks. All measurements were presented as mean ±standard deviation. Statistical data were analyzed using analysis of variance (ANOVA) and nonparametric one-way analysis.
Results: The MP group exhibited the lowest roughness (0.04 ± 0.01 µm), followed by the PDPP group (0.49 ± 0.12 µm). All groups had a passivation film composition predominantly composed of Cr2O3, with a small amount of CrO3 observed in the PDP group. PDPP exhibited minimal ion release (0.12 µg/cm2) and stable Nyquist plots. PDPP can significantly reduce the technician's post-processing time (45.75 s, p < 0.05) without compromising the adaptation of the frameworks.
Conclusions: PDPP forms a stable passivation film with extremely low ion release and a highly smooth, uniform surface. This significantly reduces the time required for manual post-processing while maintaining the accuracy of RPD frameworks, making it highly suitable for large-scale clinical framework polishing.
This study aimed to evaluate and compare the marginal and internal fit of permanent crowns fabricated using three different DLP 3D printers and their corresponding permanent resin materials. The fit was quantitatively assessed using micro-computed tomography (micro-CT) and digital 3D analysis.
A premolar tooth was prepared according to conventional ceramic tooth preparation protocols and scanned with an intraoral scanner (TRIOS 5). The resulting standard tessellation language (STL) file was imported into the software for design. A total of 24 crowns were fabricated using three different printer and resin combinations (n = 8): an Asiga printer with Saremco Crowntec permanent resin (Group S), a Denta Fab printer with Power Resin C&B permanent resin (Group C), and a SprintRay printer with Crown permanent resin (Group SP). These crowns were then re-scanned with an intraoral scanner to obtain STL files. Marginal, axial, and occlusal alignment were calculated and compared using 3D analysis software and micro-CT software. As the data were normally distributed, comparisons were made using one-way ANOVA. The significance level was set at p < 0.05.
In the marginal area, Group SP demonstrated significantly superior fit compared to Group S (p = 0.002) and Group C (p = 0.0005). No statistically significant difference was observed between Group S and Group C (p = 0.245). The findings obtained from both micro-CT and 3D superimposition analyses were consistent, confirming the reliability and agreement of the two evaluation methods.
This study demonstrates that crown restorations fabricated using 3D printers exhibit significant variations in fit depending on the type of resin employed. In particular, the resin used in Group SP tended to show improved marginal adaptation compared to Groups S and C, which exhibited comparable results. These findings may offer guidance for clinical decision-making regarding the selection of 3D printing systems and resins for crown fabrication in prosthodontic applications.
Advances in dental implantology, such as immediate loading protocols, digital planning, and improved biomaterials, have revolutionized the treatment of edentulous patients by offering faster and more predictable outcomes. This case report describes a complete digital workflow for maxillary and mandibular implant-supported full-arch prostheses in an edentulous patient with nonuniform bone shape, limited interarch space, and excessive gingival display. A full-arch immediate loading protocol, including a fixation base, a scalloped bone-reduction guide for preserving the interdental bone, an osteotomy guide, and provisional prostheses, was digitally designed and fabricated. The reverse scan technique using laboratory analog was used for fabricating definitive zirconia prostheses. The reverse scan technique integrates digital technology with clinical practice to improve the accuracy of full-arch implant restorations.
Purpose: This study aims to evaluate the readability and accuracy of content produced by ChatGPT, Copilot, Gemini, and the American College of Prosthodontists (ACP) for patient education in prosthodontics.
Materials and methods: A series of 26 questions were selected from the ACP's list of questions (GoToAPro.org FAQs) and their published answers. Answers to the same questions were generated from ChatGPT-3.5, Copilot, and Gemini. The word counts of responses from chatbots and the ACP were recorded. The readability was calculated using the Flesch Reading Ease Scale and Flesch-Kincaid Grade Level. The responses were also evaluated for accuracy, completeness, and overall quality. Descriptive statistics were used to calculate mean and standard deviations (SD). One-way analysis of variance was performed, followed by the Tukey multiple comparisons to test differences across chatbots, ACP, and various selected topics. The Pearson correlation coefficient was used to examine the relationship between each variable. Significance was set at α < 0.05.
Results: ChatGPT had a higher word count, while ACP had a lower word count (p < 0.001). The cumulative scores of the prosthodontist topic had the lowest Flesch Reading Ease Scale score, while brushing and flossing topics displayed the highest score (p < 0.001). Brushing and flossing topics also had the lowest Flesch-Kincaid Grade Level score, whereas the prosthodontist topic had the highest score (p < 0.001). Accuracy for denture topics was the lowest across the chatbots and ACP, and it was the highest for brushing and flossing topics (p = 0.006).
Conclusions: This study highlights the potential for large language models to enhance patient's prosthodontic education. However, the variability in readability and accuracy across platforms underscores the need for dental professionals to critically evaluate the content generated by these tools before recommending them to patients.
Purpose: To investigate the effect of digitally designed micro-retention features on the bond strength of additively manufactured (AM) zirconia copings.
Materials and methods: Sixty titanium base abutments (NobelParallel, NobelBiocare), pretreated with 50 µm alumina particles were divided into four groups (n = 15 per group); one group with subtractively manufactured zirconia copings (SM), and three test groups comprising one group with AM zirconia copings without any intaglio surface modification (AM-N), and two groups with digitally designed inverted pyramid-shaped micro-textures incorporated to the intaglio surface of the AM zirconia copings with two sizes: Ra 120 µm (AM-120) and Ra 240 µm (AM-240). All copings were bonded to the abutments using a conventional resin cement (Multilink Hybrid). Pull-off tensile strength was measured with a universal testing machine (Instron), and statistical analysis was performed using analysis of variance and post-hoc test.
Results: Mean tensile strength values were 574.5 N for the SM group and 450.7 N, 990.8 N, 1097 N, for AM-N, AM-120, and AM-240, respectively. No statistically significant difference was found between the SM and AM-N groups (p > 0.05) or between the AM-120 and AM-240 groups (p > 0.05). However, the AM-120 and AM-240 groups demonstrated significantly higher tensile strength compared to the SM and AM-N groups (p < 0.001).
Conclusion: Provision of inverted micro-textured pyramidal shapes provided a simulation of etched surfaces to the intaglio surface of AM zirconia copings and significantly enhanced their retention strength to Ti-base abutments compared to subtractive and non-textured AM zirconia.
This study aimed to assess and compare the effect of material type on microbial colonization over time and patient satisfaction between 3D-printed computer-aided design and computer-aided manufacturing (CAD-CAM) and conventional dentures.
This crossover randomized controlled clinical trial included 11 completely edentulous patients, each receiving two types of complete dentures: conventional dentures (comparator group) and 3D-printed CAD-CAM dentures (intervention group). Patients were randomly assigned to begin with one set of dentures and then switched to the other after 3 months, with a washout period of 2 weeks. Microbiological assessments were conducted at three time points: at the time of denture insertion (T0), after 1 month (T1), and after 3 months (T2). Patient satisfaction was evaluated 3 months post-insertion.
Microbial counts were significantly higher in the comparator group than in the intervention group at T1 (3.87 ± 0.07 vs. 3.78 ± 0.09, p = 0.023) and T2 (5.04 ± 0.03 vs. 4.98 ± 0.04, p < 0.001), with no significant difference at baseline (T0, p = 0.392). Both groups showed progressive increases in microbial counts over time; however, the comparator group consistently exhibited higher counts. Patient satisfaction was slightly higher in the intervention group (59 [57–62]) compared with the comparator group (58 [56–61]), although the difference was not statistically significant (p = 0.230).
The 3D-printed CAD-CAM dentures exhibited significantly lower microbial counts than conventional dentures throughout the 3 months. Additionally, patient satisfaction was slightly higher with 3D-printed dentures; however, the difference was not statistically significant.
Purpose: To evaluate the effects of printing technologies, storage conditions, and storage time on the intaglio surface accuracy of additively manufactured maxillary edentulous surgical guides.
Materials and methods: Forty-eight maxillary edentulous surgical guides were fabricated using three different printing technologies (n = 16): DLP (digital light processing), PJ (polyjet), and SLA (stereolithography). After postprocessing, each group was randomly divided into 2 storage conditions: dark storage (D) and light exposure storage (L). The intaglio surface of each specimen was scanned by a laboratory scanner on storage days 0, 3, 7, 14, and 28, respectively. The digital design file served as the reference, and each digitized specimen was superimposed onto the reference file using a 3-dimensional (3D) analysis software program. The root mean square (RMS) error was used to calculate trueness. The percentage of measurement data points within 1 standard deviation was used to demonstrate precision. Repeated-measures ANOVA was used to analyze the data (α = 0.05).
Results: Printing technologies (p < 0.001) and storage time (p < 0.001) significantly affected the intaglio surface accuracy of additively manufactured maxillary edentulous surgical guides. The DLP group exhibited the best printing accuracy at Day 0, with a significant decline in accuracy from Day 0 to Day 28. On the contrary, the PJ group and SLA group demonstrated superior stability during the 1-month storage. No statistical significance was found between dark storage and light exposure groups (p > 0.05).
Conclusion: Group DLP had the highest accuracy after manufacturing. Storage time only affected the accuracy of group DLP. Storage conditions had no effect on the three groups tested.
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