European Journal of Prosthodontics and Restorative Dentistry最新文献

Introduction: The application of occlusal concepts in prosthodontics is still under debate.This study assessed the impact of compensating curves on the comminution of complete denture wearers.

Methods: Seven edentulous subjects, aged 64.6 ± 2.0 years, were rehabilitated with new muco-supported complete dentures and tested in two occlusal plane settings: with and without compensating curves. A randomised triple-blind clinical trial was conducted, considering one-week and one-month as adaptation periods for dentures. After each trial, the subjects were crossed over to their respective groups. One-week was also chosen as the washout period, and after that, the subjects were re-examined. The masticatory performance and swallowing threshold were determined while chewing Optocal test food. The multiple sieve method was used for fractionation and granulometry.

Results: During the masticatory performance and swallowing threshold estimates, no differences were found between the median particle sizes obtained with the both occlusal plane conditions (P ⟩ 0.05). However, the swallowing threshold improved after one month, resulting in smaller particle sizes. Moreover, the chewing rates for the both test foods were also increased (P ⟨ 0.05).

Conclusions: These findings suggest that the compensating curves did not have an impact on the masticatory function of subjects wearing complete dentures.

Introduction: The aim of this paper is to compare the survival and success rates of endodontically treated posterior teeth restored with full veneer crowns or full cuspal coverage onlays in vivo.

Methods: A literature search using PubMed, Medline and Embase via Ovid, and The Cochrane Library retrieved English and non-English language articles from 1946 to April 2022. Electronic searches were supplemented with the use of forward citation chaining via Google Scholar.

Results: A total of eleven studies met all predetermined search criteria. Data were extracted and tabulated. Survival rates for onlays ranged from 95% to 100% at two years and 90.7% to 100% at three years with success rates ranging from 86.6% - 96.6% at two years and 86.6% to 96% at three years. Survival results for full veneer crowns were reported at 87.8% at over two years, 95.1% at three years, and 84% - 97.73% at five to ten years. Success rates have been reported at 91.11% - 92.64% at five years and 60% at six years.

Conclusions: The data suggest that the use of onlays instead of full veneer crowns in the restoration of endodontically treated posterior teeth is favourable in the short to midterm.

Introduction: Additive manufacturing is a tool with potential use in medicine and dentistry. The manufacture of metals and composites is already advanced, however, concerns about titanium hypersensitivity, tissue staining, and corrosion caused by gradual material degradation encourage research into more biocompatible alternatives.

Objective: This systematic scoping review aimed to gather studies that evaluated zirconia implants produced by additive manufacturing to describe the current stage of the printing technique and the final product.

Methods: Searches in Embase, PubMed, SCOPUS, Web of Science, and Google Scholar databases were enriched with manual searches between February and March 2021 and updated in June 2022 using keywords: zirconium implants, zirconium oxide, additive manufacturing, rapid prototyping, 3D printing, selective laser melting, and electron beam melting. The criteria included studies that evaluated or described zirconia implants obtained by 3D printing, with a direct relationship to dentistry or orthopedics.

Results: The database search resulted in 671 articles. Eight articles were selected for full reading and remained in this systematic review.

Conclusion: The printing technique for zirconia implants is promising. However, further studies are required before implants produced by the printing technique can be tested clinically. The literature with results regarding the impression product is still limited.

This case report compares a conventional and a digital workflow for manufacturing metal frameworks for maxillary and mandibular removable partial dentures (RPDs). Two sets of maxillary and mandible RPDs were produced. The metal framework of one set of RPDs was produced conventionally using the lost wax casting technique. Intraoralscanning and computer-aided designing (CAD) were used to fabricate the metal frameworks of the other set of RPDs using direct metal laser sintering (DMLS) technology. The accuracy of fit of the two sets of RPDs was evaluated after 3 months using replica models. Patient satisfaction was assessed. Two years later, the fit accuracy of the DMLS prosthesis and patient satisfaction were re-evaluated. The accuracy of fit in the maxillary RPD with the DLMS manufactured metal framework showed better results in all areas except areas of rests (457 vs. 421 μm) and the major connector (850 vs. 512 μm). The mandibular RPD with DLMS manufactured metal framework showed only in the areas of the reciprocal arm and major connector better fit accuracy compared to the conventional RPD. The patient satisfaction with the DLMS manufactured RPDs was rated equally to the conventional one. The use of digital technologies in manufacturing RPDs seems promising regarding accuracy and patient satisfaction.

Introduction: This study evaluates the impact of decontamination methods on Microtensile bond strength (μTBS) between resin cement and resin blocks.

Methods: Twenty CAD/CAM resin blocks from two manufacturers were wet-polished, sandblasted, and ultrasonically cleaned. After blood and saliva contamination, blocks were divided into subgroups: control, water rinsing, acid etching, alkaline cleaning paste, or 10-MDP containing cleaner. Resin-based cement was then applied. After 24 hours, the blocks were sectioned to obtain bars for testing. Half of the specimens were tested immediately for μTBS, and the other half underwent artificial aging. The surfaces of the blocks were inspected with a scanning electron microscope (SEM). Three-way ANOVA was performed for μTBS values (α=0.05).

Results: In one of the substrates, the positive control subgroup obtained the highest value (56,01 MPa, SD:6,96) followed by 10-MDP cleaner and universal cleaning paste, when immediately tested, with significant differences respect to the water rinsing (p⟨0.041) and acid etching (p⟨0.048) groups. After thermocycling, higher values were found in the 10-MDP cleaner (47,57 MPa, SD:8,15), but differences were not significant. In the other substrate group, the 10-MDP cleaner subgroup showed highest bond strengths (64,46 MPa SD: 10,92) at the initial test. After thermocycling, 10-MDP cleaner (58,66 MPa, SD: 9,93) gave the highest μTBS value. Significant differences between water rinsing group and the rest of subgroups (p⟨0.001), and between 10-MDP cleaner and the positive control group (p⟨0.006) were observed.

Conclusion: Cleaning after contamination improves bonding. 10-MDP containing cleaner can help to restore initial μTBS value and maintain it in the long-term.

Purpose: The aim of this study was to evaluate the surface wear and retention force of telescopic attachments made of zirconia primary crowns and poly-ether- ketone -ketone (PEKK) secondary crowns for 2-implant retained mandibular complete overdentures.

Materials and methods: Ten healthy completely edentulous patients aged 55-60 years were selected for this study. Each patient received two implants in the mandibular canine regions. Maxillary conventional complete dentures were constructed against implant-retained mandibular overdentures for all patients. Zirconia- PEKK telescopic attachments were fabricated to retain the overdentures where primary copings were constructed of zirconia and secondary ones were constructed of PEKK. Retention force and surface wear were evaluated at the time of overdenture insertion (T0), and after 6 months of overdenture use (T6).

Results: The results revealed less wear of zirconia copings compared to PEKK ones at T0 and T6. However, both materials showed insignificant wear after 6 months of overdenture use. A significant increase in retention force was observed after 6 months of overdenture use.

Conclusion: Within limitations of this study, PEKK may be considered a promising alternative material for telescopic secondary crowns construction combined to zirconia primary ones, regarding the wear resistance and the satisfactory retention forces.

Introduction: The aim of this study was to investigate the co-influence of indirect mesio- occlusal-distal (MOD) cavity geometry and inlay restoration bonding on quasi-static fracture load of the restored tooth.

Methods: Forty-eight intact human molar teeth were selected and prepared for standardized edge-shaped or round-shaped MOD cavities. The resin composite (Cerasmart, GC) inlays were bonded with the state-of-the-art inlay bonding protocol or with intentionally deteriorated bonding using n-hexane-wax solution for preconditioning. Restored teeth were loaded along the long axis of the tooth. Ultimate fracture load was recorded, and the type of fracture was visually determined and classified. Statistical analysis of load values was performed by Kruskal-Wallis test.

Results: Round-shaped cavity design with bonded restoration presented the highest fracture load (1658N). Bonding had significant influence on the fracture load of roundshaped cavity design (p=0.0003), whereas cavity design had no influence when the bonding was deteriorated (p=0.8075). In the case of deteriorated bonding, either the inlay or tooth fractured separately whereas in the bonded inlays fractures were commonly found both in the tooth and inlay.

Conclusions: According to this study, bonded inlay restoration increased fracture resistance, while cavity design had no statistical difference on fracture resistance of the restored tooth.

This study aims to investigate the effects of laser-activated irrigation on root canal dentin using different laser wavelengths. Sixty-six roots were prepared and split longitudinally. First, lasers with different power settings were tested on 34 samples, pre-etched with phosphoric acid, or remaining with a smear-layer to determine the test parameters. Selected parameters were then applied on thirty roots (9 groups) covered with smear layer: 1. Smear-layer removed; 2. Smear-layer untouched; 3. Conventional needle irrigation with NaOCl and EDTA; 4. ER:YAG laser; 5. 9.3 μm CO₂ laser; 6-9. Diode lasers. All lasers were applied in ultra-pure water as an irrigant. Root halves were examined by scanning electron microscope to analyze the intracanal dentin micromorphology on 9 consequent photos per specimen @ a magnification of 1000X. The results showed that conventional needle irrigation was effective in removing the smear-layer from coronal and middle root parts, while laser-activated irrigation had two main mechanisms: cleaning and opening of the dentinal tubules by removing the smear layer (Er:YAG laser) and melting of dentin (CO₂ and diode lasers) in all root parts. The study concluded that laseractivated irrigation with different wavelengths impacted the smear layer and root canal dentin differently through pure physical/mechanical effects.

Aim: To evaluate the microtensile bond strength of self-etching adhesive systems in dentin treated with 2% chlorhexidine digluconate (CHX).

Materials and methods: The occlusal surfaces of 20 human molars were removed and divided into eight groups: 1A, Clearfil SE adhesive (SE) with self-etching technique (TS); 1B, SE with TS and previous application of CHX; 2A, Scotchbond Universal (SBU) adhesive with TS; 2B, SBU adhesive with TS and previous application of CHX; 1C, SE with total-etching technique (TT); 1D, SE with TT and previous application of CHX; 2C, SBU with TT; 2D SBU with TT and previous application of CHX. Composite resin (5mm) was applied on the hybridized surface. Samples were subjected to microtensile test and evaluated on Scanning Electron Microscope (SEM) and with energy-dispersive X-ray (EDX).

Results: Low values of bond strength were observed in groups 1A (39,77±11,56) and 2A (40,84±12,49) comparing with 1B (22,86±5,18) and 2B (27,02±5,58). TS group presented adhesive type remover fracture while TT groups presented cohesive at the top of hybrid layer. EDX revealed the presence of CHX crystals for TS, which was not found in the TT.

Conclusion: The previous application of chlorhexidine on dentin decreased the bond strength of adhesive systems on self-etching technique.

Introduction: This systematic review examined the effect of neutralizing agents on bond strength after irrigation with sodium hypochlorite and their existing protocols in literature.

Methods: This present study adhered to the PRISMA guidelines and was registered at PROSPERO. Five electronic databases were searched (sept-2020/jan-2021) in English, Spanish, and Portuguese, without any restrictions on publication date. Cases reports, editorials and literature reviews were not included. The risk of bias was assessed using the Cochrane Collaboration tool. From the initial 7,147 studies, 2,745 were removed as duplicates and 4,382 were excluded after a title/abstract screen.

Results: Seventeen in vitro studies were included. The results showed that the higher the concentration of sodium hypochlorite, the lower the bond strength at dentine/restoration interface (p⟨0.01). Among the studies, sodium ascorbate was the most widely used neutralizer and showed the most significant results in increasing bond strength (p⟨0.01). The bond strength values were found to increase with longer application time of the neutralizing substances (p⟨0.01).

Conclusions: The use of sodium ascorbate as a neutralizing agent can reverse the negative effects of the sodium hypochlorite and improve the bond strength between dentine and resin cement, however, it isn't possible to determine the best protocol for use.