Journal of Prosthetic Dentistry最新文献

Statement of problem: Polyetheretherketone (PEEK) is an excellent restorative material, but its hydrophobicity and inertness prevent strong adhesion to resin cements.

Purpose: The purpose of this in vitro study was to examine the use of diazonium reactions for priming PEEK surfaces to improve their adhesion to resin cements.

Material and methods: Polished PEEK specimens were exposed to 7 different treatments: airborne-particle abrasion (50 µm) (APA), diazonium priming (D), adhesive (visio-link) application (A), APA followed by A (APAA), D and A (DA), APA and D (APAD), and APA followed by D and A (APADA). Nontreated specimens served as controls (C). The surface composition, roughness (Ra), and contact angle of the specimens were examined before and after treatment using X-ray photoelectron spectroscopy (XPS), profilometry, and goniometry respectively. The tensile bond strength between the treated specimens and resin cement (Panavia SA) was evaluated with a mechanical testing machine after incubation in distilled water (24 hours, at 37 ℃). The fracture surfaces were examined by using a stereomicroscope at ×40 magnification. The Kruskal-Wallis, 1-way analysis of variance, Tukey HSD, and Fisher-Freeman-Halton tests were used for statistical analysis (α=.05).

Results: Surface characterization revealed that the APA treatment resulted in the highest surface concentration of oxygen and the highest contact angle (81.3 ±4.9 degree), the D treatment resulted in the highest surface concentration of nitrogen, the DA treatment resulted in the lowest roughness and contact angle (49 ±6.2 degree), and the APAD treatment resulted in the highest roughness. Tensile test results showed the lowest tensile bond strength in the control group (0.1 ±0.1 MPa) and the highest in the APADA group (13.9 ±1.6 MPa) (P<.001). Differences were not observed among the APAA (10.8 ±0.9 MPa), DA (10.4 ±1.6 MPa), and APAD (9.8 ±1.7 MPa) treatments (P>.05). The failures of the groups were different (P<.05), with group C showing 100% adhesive failure and the APADA group showing 70% mixed failure.

Conclusions: The surface treatment of PEEK with a diazonium primer increased the bonding strength of resin cement to PEEK.

Ectodermal dysplasia, a disorder inherited through an X-linked recessive trait, is characterized by abnormalities in two or more structures that originate in the ectoderm. Dental manifestations include missing or malformed teeth. This clinical report details 16 years of interdisciplinary management, starting at age 7 and concluding after skeletal maturation, for a patient with ectodermal dysplasia. Initial treatment included an implant-assisted mandibular overdenture and a maxillary partial prosthesis to improve mastication, speech, and esthetics and to preserve alveolar bone. The prostheses were periodically adjusted to account for facial growth, and additional implants were placed after the completion of growth. The definitive rehabilitation involved maxillary and mandibular implant-supported fixed prostheses with a milled titanium thimble bar and single monolithic zirconia crowns.

Statement of problem: Monolithic zirconia crowns and porcelain-fused zirconia crowns have been evaluated with in vitro studies, but clinical evidence of their longevity is limited.

Purpose: The purpose of this retrospective cohort study was to compare the long-term cumulative survival and success rates of posterior monolithic and porcelain-fused zirconia crowns and to investigate risk factors associated with complications.

Material and methods: The study included 235 patients and 255 crowns (dropout rate:10.9%). Clinical data were analyzed for single posterior monolithic zirconia crowns and porcelain-fused zirconia crowns placed consecutively during a 10-year period and for subsequent events during follow-up. Survival curves for the monolithic zirconia crown and porcelain-fused zirconia crown groups were drawn using Kaplan-Meier analysis. Statistical differences between groups were tested using the log-rank test (α=.05). The Cox proportional hazards analysis was used to identify risk factors for crown and abutment tooth complications.

Results: The 10-year cumulative survival rates of the monolithic zirconia crown and porcelain-fused zirconia crown groups were 86.0% (95% CI, 72.8 to 99.1%) and 71.0% (95% CI, 54.6 to 87.9%), respectively. The monolithic zirconia crown group had a higher survival rate than the porcelain-fused zirconia crown group, but the difference was not statistically significant (P=.108). The 10-year cumulative success rate was higher in the monolithic zirconia crown group than in the porcelain-fused zirconia crown group, but the difference was not statistically significant (P=.071). Two risk factors were identified for crown complications alone: a molar rather than premolar crown (P=.014, hazard ratio [HR]=6.012) and a maxillary rather than a mandibular crown (P=.003, HR=9.487).

Conclusions: The 2 different types of crowns exhibited application site dependency for crown complications but not for abutment tooth complications.

Statement of problem: Studies focusing on the effect of zwitterionic polymer content on the physical and biological properties of additively manufactured (AM) ceramic-reinforced resin for dental applications are lacking.

Purpose: The purpose of this in vitro study was to evaluate the effect of different concentrations of 2-methacryloyloxyethyl phosphorylcholine (MPC) on the surface properties, mechanical properties, microbial adhesion, and cellular responses of ceramic-reinforced resins.

Material and methods: Four different groups of AM resins filled with 60 wt% silicate-based composites and varying concentrations of MPC were prepared: 0 wt% (CRN), 1.1 wt% (CRM1), 2.2 wt% (CRM2), and 3.3 wt% (CRM3). Test specimens were fabricated from the resins using digital light processing and were tested for surface roughness (S_a and R_a), flexural strength and modulus, Vickers hardness (HV), and contact angle. The adhesion of oral microbes (Streptococcus mutans and Streptococcus gordonii), cytotoxicity, and cell viability of tested resins were also assessed. One-way analyses of variances and post hoc analyses using the Bonferroni correction and Tukey HSD tests were conducted to detect statistical differences among the groups (α=.05).

Results: CRM2 exhibited significantly lower R_a (P=.020) and S_a (P=.013) values than CRM3, as well as greater flexural strength (P=.002) and modulus (P=.049), HV (P<.001), and contact angle (P=.015). CRM3 showed significantly lower flexural strength and modulus, HV, and contact angle than CRN (all P<.001). Both CRM2 and CRM3 exhibited significantly reduced adhesion of S. gordonii and S. mutans compared with CRN (all P<.001). Regardless of MPC content, the tested resins demonstrated biocompatibility and showed no signs of cytotoxicity.

Conclusions: Incorporating low-concentration MPC into AM ceramic-reinforced resins significantly changed the surface properties, mechanical properties, microbial adhesion, and biocompatibility. CRM2 provided an optimal balance between structural integrity and bacterial-repellent activity while maintaining biocompatibility.

Accurate occlusal records are vital for the success of full-arch implant restorations. Traditional methods, relying on impression materials and multiple patient visits, are often time-consuming and prone to errors due to material inconsistencies. The introduction of hybrid intraoral and extraoral scanning techniques marks a significant advancement by offering a fully digital workflow that improves precision, shortens treatment time, and enhances patient comfort. By integrating both scanning approaches, clinicians can achieve greater accuracy, minimizing occlusal vertical dimension discrepancies and optimizing articulation. This article explores how hybrid scanning is transforming full-arch restorations, offering an efficient and simplified solution that benefits both clinicians and patients, while ensuring optimal outcomes.

Statement of problem: The 3-dimensional (3D) printing of polymers and metals is a reality in dentistry; however, despite the advances, the printing of ceramic crowns is still in its infancy.

Purpose: The purpose of this review was to examine studies that evaluated the accuracy and adaptation of zirconia crowns produced by additive manufacturing with an emphasis on 3D printing.

Material and methods: Electronic databases (Embase, PubMed, SCOPUS, Web of Science, and Google Scholar) were searched between February and March 2024 using the keywords zirconium, zirconium oxide, crowns, 3D printing, additive manufacturing, stereolithography, vat polymerization, digital light processing, nanoparticle jetting, lithography-based ceramic manufacturing, accuracy, trueness, and precision, augmented by manual searches. The eligibility criteria included articles only in English and published in peer-reviewed journals.

Results: The database search resulted in 136 articles, reduced to 52 after duplicates were eliminated. After abstract reading and the application of the exclusion criteria, 14 articles remained to be read in full. All studies showed a low risk of bias.

Conclusions: The main printing techniques for zirconia crowns include material jetting and vat polymerization, which generally allow crown manufacture with accuracy and marginal adaptation within the clinically accepted range and close to that of milled crowns.

Statement of problem: Limited information is available on the relationship between the biologic complications of removable partial dentures (RPDs) assisted by short implants and conventional RPDs.

Purpose: The purpose of this pilot randomized controlled clinical trial was to compare biologic complications between patients using Kennedy Class I conventional RPDs (CRPDs) and RPDs assisted by short implants (IARPDs) after a mean period of 34 months with the prostheses in function. The secondary aim was to evaluate the success and survival rates of these short implants.

Material and methods: Thirty-three partially edentulous individuals (range 36 to 87 years), seeking treatment with RPDs and who were candidates for implant placement were enrolled and included in this pilot randomized clinical trial. Eligible participants were randomized into either the CRPD or IARPD group. LOCATOR abutments were used to convert CRPDs to IARPDs in the IARPD group. Biologic complications such as loss of abutment teeth, caries on abutment teeth, gingivitis or periodontitis on abutment teeth, implant survival, radiographic bone levels, peri-implant mucositis, and peri-implantitis were evaluated.

Results: Data were collected from 33 participants: 19 in the CRPD and 14 in the IARPD group. Nonimplant related biologic complications occurred in 44.7% of the CRPD abutment teeth and 21.4% of the IARPD abutment teeth. The most common complications were gingival inflammation and caries on the abutment teeth, with an incidence in the CRPD group of 31.6% and 28.9% and in the IARPD group of 14.3% and 14.3%, respectively. No statistically significant differences were observed in the biologic complications of IARPDs and CRPDs. The incidence of peri-implant mucositis was 42.9% and of peri-implantitis 10.7%. Early implant failure rate was 10.0%, and late implant failure rate was 10.7%.

Conclusions: CRPDs and IARPDs presented with a similar incidence of biologic complications. RPDs assisted by short implants offer a valuable treatment option when limited bone is available for alternative treatments.