European Journal of Prosthodontics and Restorative Dentistry最新文献

Purpose: CAD/CAM feldspathic ceramic (FC) materials remain used for their low cost and ease of chairside production. The purpose of this study was to describe preliminary clinical results, reporting the success and survival of FC dental crowns in a high-demand service using a simplified CAD/CAM technique.

Materials and methods: A calibrated dentist fabricated indirect restorations using the CEREC method and intraoral scanning (Cerec Omnicam, Cerec MCXL) for high-demand dental care. Forty crowns were seated adhesively and evaluated after 24 months using the newly validated UERJ criteria. Statistical analysis was performed with the McNemar test (p⟨.05).

Results: The survival clinical rate of FC CAD/CAM crowns after 24 months was 100%. However, 65% of indirect restorations presented reparable complications. No failure with loss of restoration was detected. Within the complications, most parts were in the proximal contact point, with statistically different significance in follow-up.

Conclusion: This study demonstrates that FC CAD/CAM crowns made using a simplified technique have a high clinical survival rate after 24 months, which is crucial for high-demand service. A more extended clinical evaluation period using the same criteria is necessary to draw further conclusions.

Purpose: To analyze and compare conventional and digital impressions, the effectiveness in implant-supported fixed prosthesis cases regarding accuracy, time, and patient preference.

Methods: This review followed PRISMA guidelines and was registered in PROSPERO. Two independent reviewers searched PubMed/MEDLINE, Scopus, Embase, Web of Science, and gray literature (ProQuest) for studies published until September 2023. Risk of bias was assessed using RoB 2.0 and ROBINS-I tools. Meta-analysis was performed using Rev- Man 5.4 software. A total of 27 studies were selected, including 737 patients.

Results: Qualitative analysis showed similar prosthetic results and precision for both procedures. Adjustment and impression durations were shorter with digital impressions. Twelve studies that evaluated patients' perceptions were unanimous about their preference for digital impressions. The meta-analysis revealed a significant difference in scanning time in single crowns (P =.001; MD: -7.16; CI: -10.21 to -4.10; heterogeneity P ⟨.001; l² =98%). Additionally, significant differences were observed in the analyses of adjustment duration (P =.04; MD: -3.33; CI: -6.52 to -0.13; heterogeneity P ⟨ .001; l² =90%) and patient preference (P =.003; MD: 19.02; CI: 6.36 to 31.68; heterogeneity P ⟨.001; l² =95%) favoring the digital impression.

Conclusion: Intraoral scanning provides better results concerning patient perception, impression time, and duration of adjustments.

Purpose: To evaluate effect of cement space on marginal fit of monolithic zirconia crowns after sintering, glazing, and cementation.

Materials and methods: Molar typodont teeth were prepared to receive crowns, and were scanned with a laboratory scanner to generate virtual dies. Crown design was planned with the CAD software with a simulated cement space of 60 μm or 80 μm. Zirconia crowns for the 60 μm and 80 μm groups were milled from zirconia discs. Milled crowns were sintered, glazed, and cemented. Marginal discrepancy was measured after sintering, glazing, and cementation. Measurements were carried out under 200X magnification, and data obtained were statistically analyzed.

Results: Increasing cement space from 60 to 80 μm resulted in a non-significant decrease in marginal discrepancy. Marginal discrepancy was the lowest in the post sintered specimens, and increased significantly after glazing and cementation in both the groups.

Conclusions: It was concluded that the glazing and cementation procedures significantly increased the marginal discrepancy. Increasing the cement space resulted in an insignificant decrease in the marginal discrepancy.

Clinical relevance: The results of this study suggest that 60 μm of simulated cement space is recommended for achieving clinically acceptable marginal fit of the monolithic zirconia crowns.

Objectives: This study aimed to investigate the impact of bleaching agents based on carbamide or hydrogen peroxide on dental ceramics in vitro, utilizing scanning electron microscopy (SEM) and elemental analysis via inductively coupled plasma optical emission spectroscopy (ICP-OES).

Methods: CAD/CAM ceramics (IPS e.max®CAD, IPS Empress®CAD, Vitablocs® Mark II, Celtra Duo, and inCoris TZI) were treated with bleaching agents using either 10%, 20%, 30% carbamide peroxide or with 35%, and 40% hydrogen peroxide.

Results: Surface elemental release was not significantly affected by the type or concentration of bleaching agent (p>0.05). Ion release in feldspathic ceramics was significantly higher than in other ceramic materials (p⟨0.0001). Microstructural surface changes were observed in all materials except for lithium disilicate and zirconia-reinforced lithium silicate ceramics.

Conclusions: All bleaching agents tested in this study showed a similar impact within each material type tested regarding total mass loss, elemental composition, or surface structure.

Clinical relevance: Lithium disilicate and zirconia-reinforced lithium silicate ceramics were the most resistant to bleaching agents. In contrast, feldspathic ceramic showed the highest ion release and surface deterioration when exposed to all bleaching agents tested.

Objectives: To evaluate the effect of universal adhesive type/mode and bulk-fill composite preheating on temperature changes (ΔTs) across two different dentin thicknesses.

Methods: Eighty dentin discs (2mm thickness) were randomly divided into 8 groups (n=10) based on adhesive type (All Bond Universal-ABU or Scotchbond Universal Plus- SBUP), adhesive mode (self-etching-SE, or etch-and-rinse-ER), and composite preheating (non-preheated, or preheated). K-type thermocouple wire was used to record ΔTs during adhesive light-curing (ΔT1), composite application (ΔT2), and composite lightcuring (ΔT3). After recording of ΔTs, 2mm dentin discs were reduced to 1mm thickness, and experiment was repeated. Statistical analysis was performed using ANOVA/Tukey tests (α = 0.05).

Results: Dentin thickness significantly affected ΔTs (P⟨.001), with 1mm thickness showing significant increase. Neither composite preheating, nor adhesive type/ mode significantly affected temperature changes (P⟩0.05). Both ABU/SE and SBUP/ER in preheated composite groups showed no significant difference (P⟩0.05) between 2mm (2.81±0.85°C and 1.51±0.89°C, respectively) and 1mm thicknesses (3.52±0.46°C and 2.38±0.94°C, respectively) in ΔT2. ΔT3 was significantly higher than ΔT1 and ΔT2 regardless of the dentin thickness (P⟨0.05).

Conclusion: Composite light-curing increased temperature beyond the limit that pulp can withstand, regardless of dentin thickness.

Clinical relevance: Preheated bulk-fill composite is safe for restoring deep cavities, but caution is needed during light curing.

Objectives: This study evaluated the cutting efficiency of dental burs with different surface coatings on various reconstruction materials and analyzed the microscopic changes after multiple uses.

Methods: Thirty block specimens (N=35, n=7) were prepared from various materials: CAD/CAM PMMA, direct resin composite, lithium disilicate, CAD/CAM nano-hybrid composite, and zirconia (12x4x4 mm³). The specimens were randomly assigned to cut under water cooling with one of seven bur types: Bur 1 (FG 307 CB), Bur 2 (6881.314.016), Bur 3 (FG 307 C), Bur 4 (ZR6881.314.016), Bur 5 (Prototype), Bur 6 (Prototype), and Bur 7 (Prototype). Each bur was used 10 times with a cutting depth of 3 mm. Images were taken of unused, used, and ultrasonically cleaned burs prior to data analysis (α=0.05).

Results: Cutting efficiency varied significantly by material and bur type (p⟨0.05). Bur 3 and Bur 5 were most effective for PMMA, while Burs 5, 6, and 7 excelled with direct resin composite. Bur 7 was best for CAD/CAM composite, Bur 3 for lithium disilicate, and Bur 6 for zirconia. Burs 1 and 2 consistently performed poorly.

Significance: Bur selection is important for efficient cutting, reducing chair time, material wear, and costs while improving restoration precision and bur longevity.

Objectives: This study aimed to develop an artificial intelligence system for automated classification of partially edentulous arches from panoramic radiographs using the Kennedy classification system and Applegate's rules, alongside identifying existing teeth for automated reporting.

Methods: From 5261 anonymized digital panoramic radiographs collected from publicly available datasets, 1875 high-quality images were selected and divided into training (80%), validation (10%), and testing (10%) sets. Teeth were manually annotated on the Roboflow platform following the Universal Numbering System. To enhance model robustness, data augmentation techniques were applied, expanding the dataset to 2398 images. For tooth detection, a YOLOv8s deep learning model was trained for 80 epochs (batch size: 16, learning rate: 0.01). Performance was evaluated using precision, recall, F1 score, and mean average precision. Detected teeth were used to classify partially edentulous areas based on the Kennedy system. Modification areas were identified by analyzing detected and missing teeth, measuring bounded distances in millimetres, and classifying free-end saddle gaps.

Results: The YOLOv8s model achieved a mean average precision (mAP50) of 98.1% for tooth identification, with precision and recall of 95.7% and 95.8%, respectively. For Kennedy classification, the model demonstrated precision of 0.962, recall of 0.931, and an F1-score of 0.939 across maxillary and mandibular arches.

Conclusions: The high accuracy and efficiency of this AI-driven approach can standardize classification, reduce diagnostic variability, and alleviate the workload for dental professionals, enabling seamless integration into clinical practice.

Clinical relevance: This AI system provides a consistent, accurate, and reliable method for classifying partially edentulous arches from panoramic radiographs, reducing manual assessment variability, easing practitioner workload, and enabling large-scale analysis of partial edentulism prevalence.

Objectives: This clinical trial aimed to evaluate the clinical outcomes of 3D-printed resin composite posterior fixed dental prosthesis (FDP) restorations.

Materials and methods: Between October 2020 and August 2022, 49 patients (33 females, 16 males, aged 19-60) received 68 3-unit 3D-printed resin composite posterior FDPs (ELS Even Stronger, Saremco, Switzerland). Follow-ups were conducted at baseline (2 weeks) by independent observers using modified FDI criteria, assessing anatomical form, marginal adaptation, surface roughness, color match, fracture, retention, and patient feedback. Fifty FDPs completed a 1-year follow-up, and 18 reached 2 years.

Results: The mean observation period was 14.15 months. Failures were categorized as mechanical or biological, with 19 FDPs failing: 14 mechanical (12 cohesive fractures) and 5 biological (3 needing endodontic treatment, 2 periodontal issues). Two FDPs were recemented. Three FDPs showed surface luster loss, color mismatches, and staining. The survival rate based on mechanical failures was 69.5%, dropping to 61.0% when including biological complications.

Conclusions: After 2 years, 3D-printed resin composite FDPs demonstrated acceptable performance, with most failures due to fractures in the connector region, suggesting the need for design revisions.

Objectives: This study evaluated the tensile bond strength of addition silicone impression material when used with custom trays featuring grooves and perforations, made from self-cure acrylic resin, visible light-cure (VLC) resin, and three-dimensional (3D) printed resin materials.

Materials and methods: Thirty-six custom trays were fabricated using self-cure acrylic resin (DPI Cold Cure), light-activated acrylic resin (Voco Individo Lux), and 3D-printed resin (Phrozen Aqua 4k). Each material group was divided into two subgroups based on retention methods: grooves and perforations. Tensile bond strength was tested using Digital Instron™ after applying tray adhesive (Coltene) and loading polyvinylsiloxane impression material (GC Flexceed). Data were analyzed using SPSS.

Results: Perforated light-activated acrylic resin trays showed the highest tensile bond strength (P<.005). Grooved trays had lower, but significant bond strength, while selfcure acrylic resin trays showed the weakest bond.

Conclusions: Light-activated acrylic resin trays with perforations provide superior tensile bond strength. Perforations enhance retention more than grooves, suggesting that tray material and surface design significantly affect impression accuracy.

Clinical relevance: Perforated VLC resin trays offer superior bond strength and should be considered to reduce impression distortion in clinical practice.

Introduction: It is unclear the number of times a screwdriver may be reused without loosening its efficacy or inducing damage to implant screws while keeping appropriate torque values.

Objective: Evaluate the effect of the screwdriver and internal threads on the tightening efficacy by assessing the reverse torque value (RTV).

Methods: The efficacy was tested with four groups of screws: two titanium groups and two gold-platted (n=5). Each screw was tightened 10 times at 20 Ncm using the screwdriver attached to ISD900 (NSK®). In the first protocol one implant was used for the five screws. In the second protocol for each screw a new implant was used. At each untightening, the RTV was measured and recorded.

Results: RTVs for Gold were statistically lower compared to the Titanium. The RTVs differed among the tested screws. In the first protocol, the first serie tightening/untightening differed statistically from the last three series.

Conclusion: Titanium screws from Zimmer Biomet achieve better RTV than gold-platted. By increasing the number cycles it is expected to have a decrease in the RTV. The extensive use of screwdrivers and the internal threads of the dental implants might be factors influencing the loss of RTV.