The International journal of prosthodontics最新文献

Purpose: To evaluate the antibiofilm action of 2.5 mg/mL peracetic acid (PA), 0.5 mg/mL cetylpyridinium chloride (CPC), and 160 mg/mL N-acetylcysteine (NAC) against multispecies biofilm of Streptococcus mutans, Staphylococcus aureus, Candida albicans, and Candida glabrata developed on surfaces of heat-polymerizing acrylic resin (AR) and cobalt-chromium (Co-Cr) alloy.

Materials and methods: A multispecies biofilm was grown on the surface of AR and Co-Cr specimens (Ø 12 × 3 mm). After biofilm maturation, the specimens were immersed in experimental solutions and evaluated through biofilm viability (CFU; n = 9), biofilm metabolic activity (XTT; n = 9), biofilm-covered areas (live/dead; n = 2), effects on the extracellular polymeric substance (EPS; n = 2), and biofilm morphology (n = 1). Data were analyzed by ANOVA and Tukey post-hoc test or Kruskal-Wallis followed by Dunn post-hoc test (α = .05).

Results: Overall, all evaluated solutions impacted biofilm viability. PA presented wider activity by reducing CFU of all microorganisms on both surfaces, XTT (P < .001) and live/dead (P < .001). NAC had a notorious effect in reducing the viability of bacteria without affecting the yeasts. NAC reduced XTT on AR (P = .006) and Co-Cr (P = .003) but did not reduce the aggregated biofilm layer. CPC had a distinct effect, being most effective in reducing CFU on AR compared to the Co-Cr surface. However, it did not influence XTT or the amount of residual aggregated biofilm.

Conclusions: PA provided the greatest antibiofilm action, while CPC and NAC showed intermediate action. Nonetheless, no solution was able to completely remove the biofilm adhered to the surfaces of heat-polymerizing AR and Co-Cr alloy.

Purpose: To evaluate the accuracy of intraoral scanning (IOS) impressions for multiple implants by comparing them to analog impressions.

Materials and methods: Patients with three adjacent implants in partially edentulous arches were recruited. For each arch, IOS impressions were obtained. Using the analog splinted-impression technique, casts were obtained and scanned with an extraoral scanner. Using metrology software, the distances and angles between the implants were measured in all IOS and analog impression STL files. The absolute values of the distance and angular deviation were calculated and analyzed by comparing the two impression methods.

Results: A total of 34 patients with partially edentulous arches were enrolled. The distance deviation between the IOS and analog impressions was 85.09 ± 58.73 µm, which was significantly lower than the clinically acceptable threshold for error (150 µm; P < .001). The angular deviation was 0.515 ± 0.426 degrees. Distance deviations were significantly correlated with the interimplant distances (r = 0.384, P = .001) and angulations (r = 0.278, P = .022).

Conclusions: For prostheses supported by multiple implants in partially edentulous arches, the distance deviation between the IOS and analog impression was within the clinically acceptable range of misfit and increased with increasing interimplant distance and angulation.

This article presents an efficient method for fabricating a full-arch implant prosthesis within 1 day using a verification index through a 3D-printed surgical guide. The technique involves the use of simple impression copings and laboratory analogs to ensure accurate prosthesis placement. Directly using 3D-printed surgical guides as a verification index simplifies and streamlines the procedure, offering a significant clinical advantage. This approach provides a clinically relevant advancement in prosthodontic practice by demonstrating a practical and instructive approach to enhance treatment outcomes.

Purpose: To evaluate the effect of post-printing treatment conditions, including curing time, on the optical and mechanical properties of temporary crown (TC) materials.

Materials and methods: A total of 108 specimens of TC materials (PowerResins Temp, PioNext Temporary Restoration Resin) and conventional polymethyl methacrylate (PMMA) were produced. The 3D-printed specimens were post cured for different time durations (0, 15, 30, and 45 minutes) (n = 11). During the evaluation of optical properties, color measurement and translucency measurement were performed, while surface hardness and flexural strength were tested mechanically. For structural characterization, analyses were carried out using Fourier transform infrared and Raman spectroscopy (FTIR) and scanning electron microscopy. Data were analyzed with ANOVA (P = .05).

Results: The highest color change was observed in the PioNext Temporary Restoration Resin cured for 15 minutes (11.81 ± 0.95), while the lowest was in the noncured PowerResins Temp group (1.93 ± 0.38; P < .001). Hardness and flexural strength increased significantly with curing duration (P < .001). FTIR analysis revealed optimal polymerization at 30 minutes, suggesting this duration offers a clinically favorable balance of mechanical, optical, and chemical properties.

Conclusions: Both post-curing times and different production techniques affected the microstructural, optical, and mechanical properties of the tested samples. Although longer curing time improved the mechanical properties of the materials, chemical analysis showed that 45 minutes of curing negatively affected the polymerization. Moreover, curing for 30 minutes had a positive effect on the mechanical properties without changing the chemical structure of the samples.

Purpose: To investigate the effect of cleaning procedures (ultrasonic, autoclaving) and aging methods (24 hours, 90 days, and thermocycling) on the shear bond strength (SBS) between alumina-particle air-abraded titanium (Ti) and zirconia (Zr; 3Y-, 4Y-, and 5Y-TZP) specimens luted with phosphate monomer-containing adhesive systems and resin-based composite.

Materials and methods: Lab-side-fabricated test specimens were prepared by bonding different Zr plates to Ti cylinders using a resin-based composite. The cleaning procedures included ultrasonic cleaning and purging (UUP) or two stages of purging and autoclaving (PPA). The specimens were then aged for 24 hours, 90 days, or had to endure thermocycling.

Results: Autoclaving significantly improved SBS (F [27,231] = 17.265, P < .001) compared to no cleaning and three-stage disinfection.

Conclusions: No differences were identified with regard to Zr or aging methods. Bond strength initially benefits from autoclaving but continuously approaches the comparative values over longer periods.

This case report describes a simple technique using clear aligners to intrude overerupted molars. A 27-year-old woman presented with missing mandibular left first and second molars, with the left third molar present in the arch. However, the prosthetic rehabilitation was limited by the opposing overerupted molars. Clear aligner therapy (CAT) was used to regain the necessary interocclusal space. After initial molar distalization, subsequent 2.14 and 1.3 mm of intrusion for the maxillary left first and second molars, respectively, was designed to solve the door-wedge effect dilemma. Without miniscrews, considerable intrusion (1.9 and 0.9 mm for maxillary left first and second molars, respectively) was achieved within 6 months with minimal discomfort. Radiologic and clinical examinations revealed a favorable occlusal relationship and improved alignment for both arches. Outcomes in the case revealed that intruding overerupted molars via CAT may be an effective approach.

Purpose: To evaluate the effect of varying sintering rates on the flexural strength (σ) of 3, 4, and 5 mol% yttria (Y)-containing monochrome (Mo) and multilayer (Mu) zirconia.

Materials and methods: In total, 270 specimens (11.2 × 20 × 1.5 mm) were prepared from Mo and Mu 3Y, 4Y, and 5Y zirconia and randomly sintered with regular (RS: 10°C/minute), fast (FS: 35°C/minute), and speed (SS: 70°C/minute) sintering (n = 15/group). Three-point bending test was used to determine σ. ANOVA and Bonferroni test were used to analyze significant differences of σ (α = .05). The microstructure and crystalline-monoclinic (m), tetragonal (t), and cubic (c)-phases were evaluated with a scanning electron microscope (SEM) and X-ray diffraction (XRD).

Results: The σ of zirconia was affected by zirconia type, shade pattern, and sintering rate. Significantly higher σ results were found for 3Y > 4Y > 5Y (P < .05), significantly greater σ was found for Mu > Mo (P < .05), and significant reduction of σ was found upon SS compared to RS and FS (P < .05). However, no significant effect on σ was found for varying sintering rates within each type of zirconia (P > .05). SEM indicated greater grain size in 5Y than in 4Y and 3Y. XRD indicated a higher t phase in 3Y but a higher c phase in 5Y. Mo indicated a higher c phase than Mu.

Conclusions: σ was influenced by Y content (3Y > 4Y > 5Y), shade pattern (Mu > Mo), and sintering rate (RS ≅ FS > SS). Nonetheless, varying sintering rates had no influence on σ for each type of zirconia, suggesting that sintering zirconia with RS and FS will result in higher σ and sintering zirconia at SS will result in acceptable σ for chairside cost-effective restoration.

Purpose: To investigate the efficiency of different cements for luting implant restorations.

Materials and methods: Standard restorations were bonded with different cements, including a zinc oxide-based temporary cement (ZOE), a resin-modified glass-ionomer cement (GIC), and a resin-based, eugenol-free cement (RBEFC). The restorations were stored under moist conditions and were subsequently subjected to thermal cycling and mechanical loading (TCML). Retention forces were determined with an axial tensile test, and removability of the restorations was analyzed with a pneumatic crown remover.

Results: GIC provided significantly higher retention forces than RBEFC, which provided significantly higher values than ZOE. After storage, retention forces were significantly higher than after TCML. Regarding removability, no significant differences were identified between ZOE and RBEFC, but a significantly higher number of applications was required to remove restorations luted with RBEFC.

Conclusions: All cements provided sufficient retention forces, yet removal of restorations might be more demanding if luted with RBEFC.

Purpose: To investigate the available evidence on the accuracy of conventional and digital workflows for complete-arch implant-supported frameworks.

Materials and methods: This scoping review was conducted according to the five-stage framework of Arksey and O'Malley. A systematic literature search was performed adhering to the PRISMA guidelines to identify studies with a direct comparison of conventional and digital methods for the fabrication of complete-arch implant-supported frameworks. A total of 58 in vitro studies with a focus on edentulous arches with at least four implants published between 2000 and 2024 were included. The reported outcomes were examined to determine the value of a statistical analysis in estimating the cumulative workflow error from the individual errors at each stage.

Results: Evidence on the accuracy assessment of digital and conventional workflows for complete-arch implant-supported frameworks is available. However, studies with the same assessment methods and outcome units appear to be too heterogeneous to perform a statistical analysis of error accumulation. While there is no consensus in the impression and cast fabrication stage, digital techniques show superior accuracy for the fabrication of complete-arch implant-supported frameworks compared to conventional casting.

Conclusions: In vitro studies assessing the accuracy of entire workflows and classifying their outcomes regarding clinical relevance are lacking.