Journal of prosthodontic research最新文献

Patients: A 56-year-old man with a left-sided cleft lip and palate was referred to our department due to mastication and speech difficulties. His existing prostheses have become unstable owing to changes in the remaining dentition over 10 years. For the fabrication of the new interim maxillofacial prostheses, a digital impression technique was selected as the conventional technique posed medical risks due to hypermobile teeth and maxillary defects. New interim maxillofacial prostheses were fabricated using a combination of the digital impression technique and a bite-seating impression, performed with trial prostheses and impression material. The patient has been using the new interim prostheses comfortably since delivery. The oral functional evaluation yielded favorable results.

Discussion: Patients with cleft lip and palate should use their existing maxillofacial prostheses during the fabrication of new ones, even if they are of suboptimal quality. Although addressing these issues using conventional techniques is challenging, digital technology provides a viable solution. However, impression material is essential for capturing mucosal defects and complex anatomy in cleft lip and palate cases; therefore, digital data should be supplemented by either well-adjusted existing prostheses or bite-seating impressions using impression material before new prostheses fabrication. Although his occlusal force was lower than the criterion for the oral hypofunction test, his masticatory performance remained favorable. Speech analysis revealed persistent air leakage; however, all scores improved with the prostheses.

Conclusions: Digital technology has enabled the safe fabrication of interim maxillofacial prostheses, resulting in improved masticatory and speech performance.

Purpose: Evaluation of the impact of ultraviolet (UV) photofunctionalization on titanium-cement interfaces, specifically its ability to transform titanium into a high-energy surface and enhance crown retention.

Methods: Commercial titanium abutments (standard: 4.0 mm; long: 5.5 mm) were treated with vacuum UV (VUV) light at 172 nm for 1 min. Milled polymethyl methacrylate crowns were cemented using resin-modified glass ionomer cement. Tensile testing quantified the maximum tensile load and interfacial energy. Surface changes were analyzed using contact angle measurements and X-ray photoelectron spectroscopy (XPS). Post-failure interfaces were examined via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX).

Results: UV-treated standard-length abutments exhibited a 4.1-fold increase in maximum tensile load and 27-fold increase in bonding energy compared with untreated control counterparts. UV-treated long abutments showed a 4.6-fold increase in maximum tensile load and 54-fold increase in bonding energy. UV treatment rendered the titanium surface superhydrophilic and low in carbon, whereas untreated specimens remained carbon-rich and hydrophobic. UV-treated long abutments exhibited 3.1-fold higher energy than UV-treated standard abutments. Notably, long abutments without UV treatment did not outperform standard untreated abutments. SEM and EDX confirmed extensive residual cement on UV-treated abutments, indicating cohesive failure and strong interfacial bonding.

Conclusions: A 1-min UV photofunctionalization transforms titanium into a superhydrophilic, high-energy surface that significantly enhances cement bonding. This physicochemical surface strategy outperforms geometric modifications alone. As a rapid, non-invasive approach, UV photofunctionalization may establish a new standard for durable implant-supported restorations, reducing prosthetic failure and influencing both material selection and clinical and laboratory workflows.

Purpose: To evaluate how the depth of the intaglio surface on the denture and the scanning method influence the trueness using two types of intraoral scanners (IOS) for complete dentures.

Methods: Four complete denture types (Extra-deep, Deep, Moderate, Shallow) with varying intaglio surface depths (Extra-deep > Deep > Moderate > Shallow) for the maxilla and mandible were designed using two computer-aided design software, resulting in 8 denture models. Reference data were obtained using a laboratory scanner (D2000). Each denture was scanned eight times using two IOSs: a confocal microscopy-based scanner (Trios 5) and a dual-triangulation-based scanner (i700), resulting in 64 scans per IOS (128 scans in total). Scan data were superimposed using three-dimensional editing software, and the root mean square (RMS) was calculated to assess trueness. Statistical analyses included the Shapiro-Wilk test for normality and two-way analysis of variance with Bonferroni correction (α=0.05).

Results: For Trios 5, the RMS value for the Extra-deep was significantly higher than that for the Moderate and Shallow in both the maxilla and mandible. Furthermore, the Deep showed significantly higher RMS values than the Shallow in the maxilla. For i700, the RMS values did not significantly differ among the denture types. Across all denture types, the RMS values for i700 were significantly higher than those for Trios 5.

Conclusions: The depth of the intaglio surface on the denture influenced trueness when using the Trios 5. The Trios 5 showed higher trueness than the i700 did across all denture types.

Purpose: This systematic review evaluates the effectiveness of artificial intelligence (AI) models in dental implant treatment planning, focusing on: 1) identification, detection, and segmentation of anatomical structures; 2) technical assistance during treatment planning; and 3) additional relevant applications.

Study selection: A literature search of PubMed/MEDLINE, Scopus, and Web of Science was conducted for studies published in English until July 31, 2024. The included studies explored AI applications in implant treatment planning, excluding expert opinions, guidelines, and protocols. Three reviewers independently assessed study quality using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Quasi-Experimental Studies, resolving disagreements by consensus.

Results: Of the 28 included studies, four were high, four were medium, and 20 were low quality according to the JBI scale. Eighteen studies on anatomical segmentation have demonstrated AI models with accuracy rates ranging from 66.4% to 99.1%. Eight studies examined AI's role in technical assistance for surgical planning, demonstrating its potential in predicting jawbone mineral density, optimizing drilling protocols, and classifying plans for maxillary sinus augmentation. One study indicated a learning curve for AI in implant planning, recommending at least 50 images for over 70% predictive accuracy. Another study reported 83% accuracy in localizing stent markers for implant sites, suggesting additional imaging planes to address a 17% miss rate and 2.8% false positives.

Conclusions: AI models exhibit potential for automating dental implant planning with high accuracy in anatomical segmentation and insightful technical assistance. However, further well-designed studies with standardized evaluation parameters are required for pragmatic integration into clinical settings.

Purpose: To evaluate and compare the effect of bulb wall thickness and build angle on the trueness and weight of an open-hollow obturator fabricated using digital light processing (DLP) technology.

Methods: A 3D model of an edentulous maxillary jaw with an Aramany Class I defect was designed using computer-aided design (CAD) software, and 45 obturators with bulb wall thicknesses of 1, 2, and 3 mm were fabricated using a DLP printer at build angles of 0, 45, and 315 degrees, respectively. The weight of each obturator was measured. All obturators were scanned using cone-beam computed tomography, and the data were converted to the standard tessellation language format. The CAD and scanning data were superimposed for inspection. Statistical analysis was performed using two-way analysis of variance (ANOVA) and Tukey's test.

Results: The two-way ANOVA showed a significant effect of the build angle on the denture base (P < 0.001); however, the bulb wall thickness had no significant effect (P = 0.73). Both the bulb wall thickness and build angle significantly affected the inner and outer bulb surfaces (P < 0.001), and a significant interaction between these factors was observed (P < 0.05). Significant differences were observed between bulbs (P < 0.001). Additionally, weight was significantly affected by both factors and their interactions (P < 0.001).

Conclusions: The bulb wall thickness and build angle significantly influenced the trueness and weight of the open-hollow DLP obturator, with the least error observed at a zero-degree build angle.

Purpose: This in vitro study evaluated the adaptation and fracture resistance of screw- and cement-retained implant-supported restorations using lithium disilicate crowns cemented onto titanium bases and universal abutments of different heights.

Methods: Thirty crowns were designed, milled, and divided into three groups: TBA (titanium base abutment - 4.7-mm-height and 4.65-mm-diameter), UA-4 (universal abutment - 4.0-mm-height and 4.5-mm-diameter), and UA-6 (universal abutment - 6.0-mm-height and 4.5-mm-diameter) (n=10). The abutments were placed in a mandibular first premolar model, torqued to 20 Ncm, and scanned using a digital intraoral scanner. The crowns were designed and fabricated using computer-aided design/computer-aided manufacturing technology. Adaptation was assessed using a stereomicroscope before and after ceramic sintering and after cementation with RelyX Ultimate resin cement. Fracture resistance was evaluated using a universal testing machine, and the failure modes were analyzed. The collected data were subjected to statistical analysis using one-way ANOVA and the Tukey least significant difference test (α=0.05).

Results: The abutment type influenced restoration adaptation and fracture resistance. No differences in adaptation were found before or after luting (P > 0.05). However, after sintering, the TBA group exhibited smaller marginal gaps than the UA-4 (P = 0.0339) and UA-6 (P = 0.0006) groups. TBA showed a higher fracture resistance than UA-4 (P = 0.0093); no differences were observed between TBA and UA-6 or between UA-4 and UA-6 (P > 0.05). The UA-4 and UA-6 groups showed higher ceramic fracture rates, whereas the TBA group showed increased abutment deformation and ceramic fractures.

Conclusions: The type and height of abutments influenced the fracture of screw-and-cement-retained implant-supported restorations.

Purpose: This study aimed to evaluate the performance of 3D-printed denture base resins (DBRs) compared with conventionally printed DBRs, examine their biofilm formation and physical properties, and determine the viability of 3D-printed DBRs as a superior alternative in removable prosthodontics.

Methods: The DBR samples were fabricated using traditional packing (TRA), milling (MIL), and 3D printing (3DP) methods. All samples were serially polished with an abrasive paper. Biofilm formation was assessed using SYTO 9 and propidium iodide staining as well as confocal laser scanning microscopy. Color and dimensional stability were evaluated following immersion in artificial saliva, and volumetric changes were assessed after the samples were subjected to thermocycling (TC) and highly accelerated stress (HA) aging. Statistical analyses were conducted using one-way analysis of variance with post-hoc Tukey's honestly significant difference test (α = 0.05).

Results: MIL exhibited the highest Aggregatibacter actinomycetemcomitans biofilm coverage (94.59%), whereas 3DP exhibited the lowest coverage (58.86%). All DBRs exhibited slight perceptible color changes after immersion in artificial saliva, with 3DP demonstrating the least dimensional changes (2.86%). Following TC and HA aging, all DBRs experienced a volume increase, with TC inducing greater volumetric changes (2.8%-3.9%) than HA (0.8%-2.4%); however, the difference was not statistically significant (P < 0.05).

Conclusions: The 3D-printed DBRs demonstrated superior resistance to biofilm formation, along with good color and dimensional stability. These properties indicate strong potential for enhanced hygiene maintenance, esthetics, and long-term clinical performance in denture applications.

Purpose: To investigate the effect of ceramic material (lithium disilicate, LDS vs. composition-gradient multilayered zirconia [4Y-PSZ and 5-PSZ], Z) and ceramic layer thickness (0.5 mm, 1.0 mm, and 1.5 mm) on fatigue performance and failure load of occlusal veneers on molars.

Methods: Seventy-two CAD-CAM-fabricated occlusal veneer restorations (IPS e.max CAD; IPS e.max ZirCAD Prime Esthetic, Ivoclar Vivadent) were divided into six groups (n=12, LDS-1.5, LDS-1.0, LDS-0.5; Z-1.5, Z-1.0, Z-0.5). Restorations were adhesively cemented (Variolink Esthetic DC, Ivoclar Vivadent) to dentin-analogue composite dies (Z100, 3M ESPE) and exposed to thermomechanical fatigue (1.2 million cycles, 49 N, 1.6 Hz, 5-55° C). Single-load-to-failure was tested with a universal testing machine. Data were analyzed using ANOVA with Tukey post-hoc tests and t-tests (P < 0.05).

Results: The overall success rate across all materials and layer thicknesses was 91.7%. Half of the specimens of group Z-0.5 revealed cracks after chewing simulation. Occlusal veneers fabricated from LDS withstood significantly higher failure loads than gradient multilayered zirconia veneers in all tested thicknesses. The mean failure load values led to the following ranking: 3194 N (LDS-0.5)>2683 N (LDS-1.0)>2338 N (LDS-1.5)>1744 N (Z-1.5)>1310 N (Z-0.5)>1198 N (Z-1.0).

Conclusions: Ultrathin LDS occlusal veneers outperformed thin and standard thick counterparts, as well as gradient multilayered zirconia veneers at all thickness levels. Ultrathin gradient multilayered zirconia occlusal veneers were prone to cracks during thermomechanical fatigue. Individual mechanical properties need to be considered when aligning the restoration within the multilayered zirconia blank.

Purpose: This systematic review evaluated the clinical performance, physical-mechanical properties, and accuracy of removable partial denture (RPD) frameworks fabricated using three-dimensional (3D) printing technologies-specifically, selective laser sintering (SLS), selective laser melting (SLM), and direct metal laser sintering (DMLS)-compared to those produced by conventional casting or methods using a partial digital workflow.

Study selection: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, a literature search was conducted in the PubMed, Scopus, Web of Science, and Cochrane databases in October 2024. Studies were included if they compared the fit, accuracy, mechanical and physical properties, and clinical outcomes of metal RPD frameworks made using 3D printing technologies with those produced using conventional casting or partial digital methods. The risk of bias was assessed using appropriate tools (modified CONSORT, ROB2, and ROBINS-I) based on the study design and a qualitative analysis was conducted. This study received no funding and was registered with PROSPERO (#CRD42024597225).

Results: Thirty studies were included: 12 compared 3D printing technologies with conventional casting, eight with partial digital methods, and 10 with both. Clinically, 3D-printed frameworks could improve retention and patient satisfaction. The laboratory results showed higher density, better mechanical properties (yield strength, surface roughness, and microhardness), and varied accuracy by component and method, with SLM and DMLS often outperforming conventional casting. The evidence was limited by methodological variability, a moderate risk of bias in many studies, and inconsistencies across the study designs and parameters.

Conclusions: 3D-printed RPD metal frameworks demonstrated clinical accuracy and mechanical-physical performance comparable or superior to those of conventional and partially digital methods for RPD frameworks, with ongoing advances expected to further enhance their precision and clinical applicability.

Purpose: To evaluate the effects of various cleaning methods on the bond strength between lithium disilicate (LS₂) ceramics and resin cement under short- and long-term aging conditions using network meta-analysis (NMA) and pairwise meta-analysis (PMA).

Study selection: An electronic search of seven databases (PubMed, Scopus, Embase, Web of Science, Google Scholar, Defense Technical Information Center, and LILACS) with a manual search of the reference lists was conducted for articles published up to March 10, 2025. Eligible studies included those that assessed the bond strength of LS₂, either uncontaminated or contaminated with human saliva, fit-checking materials, try-in paste, or their combinations, using different cleaning methods. Risk of bias was evaluated using the RoBDEMAT tool. A frequentist multivariable random-effects model was used to calculate the effect sizes.

Results: Fifteen studies met the inclusion criteria. Under short-term aging conditions, NMA showed higher bond strengths in the uncontaminated LS₂ group and the contaminated groups cleaned with hydrofluoric acid etching, commercial ceramic cleaning agents, or phosphoric acid etching than those uncleaned or cleaned with water or alcohol. In long-term aging, PMA and NMA exhibited higher bond strengths in the uncontaminated LS₂ group and contaminated group cleaned with phosphoric acid etching than those contaminated groups cleaned with water or alcohol.

Conclusions: Phosphoric acid etching effectively eliminates contaminants, whereas the application of water or alcohol is ineffective. Although ceramic cleaning agents effectively decontaminate surfaces under short-term aging conditions, their performance deteriorates over time, potentially compromising long-term bond durability.