The International journal of prosthodontics最新文献

Purpose: To address the challenges of obtaining accurate digital impressions for the fabrication of fixed restorations on multiple implants in full-arch edentulous cases.

Materials and methods: An approach to the use of extended design scan bodies (EDSBs) and advanced digital technologies in full-arch implant rehabilitation is presented. Clinical and laboratory treatment sequences are illustrated, focusing on intraoral scanning, restorative materials, and digital fabrication techniques.

Results: EDSBs provide accurate digital impression results, maintaining precision over longer distances and proving effective for both fixed and removable implant restorations.

Conclusions: Using EDSBs with L-shaped and T-shaped extensions creates a stable reference framework during scanning, overcoming the lack of reliable landmarks on edentulous mucosa and enhancing digital impression accuracy and clinical outcomes.

Purpose: To determine which biomaterials are referred to as hybrid ceramics and to describe their principal properties, when available.

Materials and methods: Two reviewers executed a literature search up to June 15, 2024, in three electronic databases: PubMed, Web of Science, and Scopus. All commercial names of biomaterials labeled as hybrid ceramic were retrieved if pertinent to the dental prosthesis. Articles referring to hybrid ceramic abutments were excluded.

Results: Overall, 771 studies mentioning a hybrid ceramic were identified, and 226 were selected for this bibliometric study. A total of 25 biomaterials have been identified labeled as hybrid ceramics, including 4 experimental biomaterials, 2 indirect lutable composites, 3 glass- ceramics, 2 printable permanent crown resins, and 14 resin-based CAD/CAM blocks. Their mechanical, optical, and biologic properties have been described when available.

Conclusions: Hybrid ceramics are popular in the research field yet are often mislabeled. A new, detailed classification is needed.

Purpose: To investigate the neuromuscular position of the mandible in the fifth and final part of a comprehensive investigation of the positions of the temporomandibular joint condyles.

Materials and methods: The neuromuscular condylar positions were recorded by four independent operators in 81 fully dentate subjects with healthy oral function using a central bearing point system and rapid closing movements. The most frequent adduction point was determined, and the recordings were repeated twice for each subject. The subjects' maxillary casts were mounted in an articulator using an individual facebow transfer, and subsequently the mandibular casts were mounted with a central bearing point registration on the tip of the Gothic arch, ie, in centric condylar position (CR). A custom-made electronic measuring articulator was used to determine the spatial distance between the condyles in centric relation, maximal occlusion, and the newly determined neuromuscular position.

Results: The reproducibility of the neuromuscular registrations was on average 0.52 ± 0.16 mm (range 0.04 to 2.53 mm) with the right and left side averaged. The average spatial distance of the condyles between maximal intercuspal position (MI) and neuromuscular position was 0.88 ± 0.30 mm (range 0.12 to 5.98 mm), again averaged for the right and left sides, whereas that between the CR and the neuromuscular position was 0.83 ± 0.27 mm (range 0.10 to 7.89 mm).

Conclusions: The neuromuscular mandibular position is neither identical to MI nor to CR. It can therefore be concluded that the registration of the neuromuscular adduction field should not be recommended for prosthodontic restorations in dentate or edentulous patients.

Purpose: To assess the impact of toothbrushing and thermocycling on color, opalescence, fluorescence, and surface of extrinsically stained CAD/CAM ceramics.

Materials and methods: Specimens (n = 20) of VITA Mark II (VBII), VITA Suprinity (SUP), and IPS e.max ZirCAD (ZIR) were stained and glazed, then divided into two groups based on dentifrice (n = 10; conventional or whitening). Aging was simulated via 100,000 toothbrushing cycles followed by 12,000 cycles of thermocycling. Color differences (ΔE00) and opalescence were calculated. Images under ultraviolet (UV) lamp were obtained for fluorescence analysis. Surface roughness was analyzed using 3D laser confocal microscopy, and chemical elemental characterization was determined using energy-dispersive X-ray spectroscopy (XEDS). Statistical analyses (α = .05) included two-way ANOVA and Tukey HSD tests for ΔE00 and three-way ANOVAs with Sidak post hoc test for opalescence, fluorescence, and surface roughness. ΔE00 values were compared to perceptibility and acceptability thresholds.

Results: Higher ΔE00 were observed for VBII in the whitening group and SUP in the conventional group. All ΔE00 values remained below perceptibility. ZIR exhibited the lowest opalescence and fluorescence before and after aging. SUP and ZIR showed a significant reduction but continued to exhibit fluorescence after aging. VBII whitening and SUP conventional exhibited increased roughness. XEDS indicated that extrinsic characterization persisted on the surface with subtle changes in elemental composition after aging.

Conclusions: The findings suggest that toothbrushing with different dentifrices and thermocycling can impact the esthetic outcome and surface of stained CAD/CAM ceramics. Despite these, the materials evaluated maintained color stability and resisted the proposed aging.

Purpose: Restoring severely destructed anterior teeth without a ferrule remains a clinical challenge, and the choice between endocrowns and post-core systems is still debated. This study aimed to compare the fracture strength and failure modes of maxillary central incisors restored with conventional and CAD/CAM post-core systems versus endocrowns fabricated from different materials.

Materials and methods: Fifty endodontically treated maxillary central incisors were decoronated and divided into five groups:Glass-fiber post/composite core (F); CAD/CAM glass-fiber single-piece post-core (CF); CAD/CAM polyetheretherketone (PEEK) single-piece post-core (CP); hybrid ceramic endocrown (HE); lithium disilicate endocrown (LE). Hybrid ceramic crowns were produced on the post-core restorations. After thermocycling, fracture strength (N) was evaluated using a universal testing machine. Then the failure modes were examined under stereomicroscope. Statistical analysis was performed using Kruskal-Wallis and Tukey tests (P= .05).

Results: Group CF exhibited the highest fracture strength (331.624 N) and a 60% repairable failure rate. However, group F exhibited a 100% repairable failure, followed by the group CP, which showed 80% repairable failure. Among the endocrowns, HE demonstrated significantly higher fracture strength (313.9 N) compared with LE (128.9 N, P< .05), although both showed 60% repairable failures.

Conclusions: CAD/CAM glass-fiber post-cores and hybrid ceramic endocrowns provided superior fracture strength with predominantly repairable failures. In view of their simplified workflow and cost-effectiveness, hybrid ceramic endocrowns may be regarded as a clinically reliable restorative option for anterior teeth lacking a ferrule. In addition, the repairable nature of failures in glass-fiber posts plays a key role in preventing irreversible failures.

Purpose: Large language models (LLMs) have gained significant attention and are increasingly considered as decision-support tools in healthcare. Nevertheless, their accuracy in relation to established prosthodontic guidelines remains underexplored. The purpose of this study was to evaluate and compare the evidence-based potential of answers provided by 4 LLMs to common clinical questions regarding denture care and maintenance.

Material and methods: A total of 10 open-ended questions pertinent to denture care and maintenance were posed to 4 distinct LLMs, namely ChatGPT 4o, Google Gemini Advanced, Microsoft Copilot, and DeepSeek V3. The answers were evaluated independently by 2 prosthodontists against established guidelines for comprehensiveness, scientific accuracy, clarity, and relevance. Differences were analyzed using Friedman and Wilcoxon signed-rank tests. To assess intra-evaluator reliability, a reevaluation of the LLM responses was performed after 4 weeks, and Cronbach's α and interclass correlation coefficient (ICC) were used (α=.05).

Results: ChatGPT 4o and Google Gemini Advanced recorded the highest mean scores (8.5 out of 10), followed by DeepSeek V3 (8.4 out of 10) and Microsoft Copilot (8.0 out of 10). No statistically significant differences were observed among the models.

Conclusion: In this limited set of denture-care questions, LLMs often provided high-quality responses that aligned with ACP denture care guidelines, although occasional inaccuracies were observed. Their use shows potential as additional decision-support tools, but insights are limited to routine denture hygiene and maintenance questions. Caution and expert supervision are still crucial, as LLMs can't replace dental professionals in prosthodontic treatment or patient care.

Background: Emerging technologies have revolutionized the digital workflow in the fabrication of restorations. The reverse scan technique has been introduced as a solution for full-arch rehabilitation to simplify the recording of implant positions, as well as to improve splinted impression making and the recording of implant positions. Recent studies reported favorable outcomes for complex rehabilitation in full-arch, multiple-implant-supported restorations. However, no article in the current literature search on outcomes for short-span edentulous patients in the esthetic zone was found.

Case presentation: One of the critical aspects of achieving esthetic rehabilitation that is in harmony with pink esthetics is to provide a prototype or interim restoration that can be transferred into a definitive restoration. This reverse scanning technique enables the scanning of interim restoration designs and aesthetic parameters, allowing for the reverse engineering of the confirmed prosthetic volume from definitive materials. This patient report aims to demonstrate the proof of concept that reverse scan bodies can also be utilized as an alternative. Seventy-two-year-old female patient needs rehabilitation of maxillary four anterior incisors with implant supported screw retained restoration presented with two-piece design implants with two screw-retained abutments to support a 4-unit fixed dental prosthesis.

Conclusion: This patient report demonstrates that a reverse scan from the interim restoration used as a prototype, digitally recorded with an intra-oral scanner (Trios 4, 3Shape, Copenhagen, Denmark), can be used as a valid alternative workflow to fabricate a monolithic zirconia oxide restoration as the definitive restoration.

Purpose: The aim of the present in-vitro study was to evaluate the effect of various post-curing times (15, 30, and 45 minutes) and conditions (dry and glycerin-immersion) on the mechanical properties of a permanent crown resin used for 3D-printing.

Materials and methods: Crowns (n=90) and bars (n=90) were fabricated using a permanent crown resin (Saremco Crowntec) with a 3D printer (Nextdent 5100) in accordance with the manufacturer's recommendations. After washing with alcohol, the printed specimens were divided into 6 groups (n=15). Post-curing (LC-3DPrint Box) was performed under dry and glycerin- immersion conditions for 15, 30 and 45 minutes. A universal testing machine was used to measure the fracture resistance of crowns and the flexural strength of bars in a three-point bending test. Statistical analysis was performed using independent t-tests and one-way ANOVA (α =.05).

Results: Fracture resistance was not significantly different between the dry and glycerin- immersion groups (P ˃ .05). Flexural strength significantly decreased in the glycerin-immersion specimens, compared with the dry ones in the 15-minute post-cured group (P < .05). Fracture resistance increased, in accordance with the increment in the post-curing time, in both dry and wet conditions, even though no significant difference was obtained for post-processing times of longer than 30 minutes (P ˃ .05). In the glycerin-immersion group, flexural strength increased with post-curing time, showing a significant difference between 15 and 45 minutes (P < .05).

Conclusions: Post-curing time and conditions influence the mechanical features of the investigated 3D printed permanent crown material. The increment of the post-curing time had a favorable influence on the material's mechanical properties.

Background: This study evaluated the influence of self-image and self-esteem on overall quality of life and oral health in edentulous individuals before and after rehabilitation with new complete dentures.

Methods: An observational clinical study was conducted with 26 edentulous adults. Participants completed validated questionnaires (GOHAI, DIDL, RSES, SHS, BASS, MBSRQ-AS, ST, FOE) before treatment and 2-3 weeks after denture delivery. Pre- and post-treatment differences were analyzed using the Wilcoxon signed-rank test, and relationships among domains were examined using Spearman's correlation (α = 0.05).

Results: Significant improvements were observed in oral health perception and several psychosocial domains, including GOHAI (26.0 → 28.5; p = 0.015), self-esteem on the RSES (-0.25 → 1.0; p < 0.001), smile frequency on the ST (11.0 → 11.5; p = 0.006), and appearance-related dimensions of the DIDL (p < 0.001). Satisfaction with dental and facial-related body areas also increased, as reflected by improvements in BASS-General (37.5 → 31.0; p = 0.008), Teeth (3 → 1; p < 0.001), Mouth (2 → 1; p = 0.006), and Profile (2 → 1; p = 0.001). Spearman's analyses revealed statistically significant correlations among functional, esthetic, and psychosocial domains, of weak to moderate strength. No significant changes were detected for SHS, FOE, or the MBSRQ-AS subscales (p > 0.05).

Conclusion: Rehabilitation with dentures resulted in meaningful short-term improvements in oral-health perception, self-esteem, and esthetic self-perception. Weak to moderate correlations among functional, esthetic, and psychosocial domains indicate interconnected early changes, while broader emotional constructs showed no significant variation.

Purpose: This study aimed to compare the mechanical and surface properties of hybrid ceramic materials fabricated using different techniques for fixed dental restorations and to evaluate the clinical relevance of digital manufacturing. Five permanent hybrid resin materials produced via 3D printing and one hybrid ceramic fabricated by milling were assessed in terms of fracture resistance, surface roughness, and microhardness.

Materials and methods: Six groups were formed: five 3D-printed resins and one milled ceramic. For each group, 20 molar-shaped crowns were fabricated and divided into pre-aging and post-aging subgroups for fracture resistance testing. Additionally, 120 disk-shaped specimens were prepared. Crowns were cemented using resin cement under finger pressure and tested with universal testing machine. Surface roughness was measured with a profilometer, and microhardness was assessed using Vickers hardness tester. All specimens underwent thermal aging before retesting. Data were analyzed using SPSS.

Results: Significant differences in fracture resistance were found among groups (p<0.05). Flexcera Smile Ultra+ showed the highest values. Aging reduced fracture resistance in all groups. Senertek P-Crown V3 and Vita Enamic had higher surface roughness initially, with only Senertek P-Crown V3 showing significant post-aging decrease. The milled ceramic group showed higher microhardness than all 3D-printed groups. Post-aging, hardness increased in all but the Vita Enamic group.

Conclusion: Material selection and fabrication technique should be based on clinical requirements. Milled ceramics provide superior mechanical strength. However, the surface roughness of 3D-printed materials remained above the clinically acceptable threshold of 0.2 µm.