Search Results (51)

Background/Objectives: Full-arch implant-supported prostheses have become a widely accepted solution for edentulous patients, yet long-term biological and mechanical complications remain a clinical concern. Methods: This retrospective study included 70 fully edentulous patients (362 implants) rehabilitated with either fixed or removable implant-supported prostheses. Data were collected on demographics, medical status, type and location of prostheses, implant type, abutments, method of fixation, and complications. Statistical analysis included Fisher’s exact test, the Mann–Whitney U test, and chi-squared tests, with a significance level set at p < 0.05. Results: Mechanical complications occurred in 41.4% of patients (29 out of 70), with framework fractures reported in eight cases (27.6%), ceramic chipping in six cases (20.7%), and resin discoloration in four cases (13.8%). The prostheses were fabricated using monolithic zirconia, metal–ceramic crowns, zirconia on titanium bars, and hybrid resin/PMMA on cobalt–chromium frameworks. Gingival inflammation was also noted in 41.4% of cases (n = 29), predominantly in posterior implant regions. Younger patients and those without systemic diseases showed a significantly higher incidence of mechanical complications. Conclusions: Two years post-treatment, mechanical and biological complications appear to be independent phenomena, not significantly associated with most prosthetic variables. Patient-specific factors, particularly age and general health status, may have greater predictive value than prosthetic design. Limitations of the study include its retrospective design and the lack of radiographic data to assess peri-implant bone changes. Full article

Background/Objectives: Guided bone regeneration (GBR) is a regenerative technique used to treat maxillary osseous defects to enable implant placement for prosthetic rehabilitation. It is generally performed with the use of barrier membranes and bone substitute materials of human or animal origin. Here, we report the clinical and histological outcomes of a horizontal GBR, treated using only synthetic biomaterials. Methods: A graft of nanocrystalline hydroxyapatite (NH) embedded in a silica gel matrix was used to fill a horizontal bone defect. The graft was covered with a titanium-reinforced dense polytetrafluoroethylene (TR-dPTFE) membrane, and primary closure was completed and maintained for 10 months. Then, the site was re-opened for membrane removal and implant insertion. During implant bed preparation, a bone biopsy was obtained for histological evaluation. A metal–ceramic crown was fitted, and the 5-year follow-up after prosthetic loading showed clinical and radiographically healthy tissues. Results: Histological examination revealed good integration of the biomaterial into the surrounding tissues, which were composed of lamellar bone trabeculae and connective tissue. New bone formation occurred not only around the NH granules but even inside the porous amorphous particles. Conclusions: The combination of NH and the TR-dPTFE membrane produced good clinical and histological results, which remained stable for 5 years. Full article

This study aimed to evaluate prosthetic complications, implant survival rates, and marginal bone loss in implant-supported monolithic restorations compared to metal-ceramic restorations. The study was registered in PROSPERO (CRD420251022336) and conducted following the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. A systematic search was conducted in the electronic databases MEDLINE/PubMed, Web of Science, Scopus, Embase, and ProQuest for articles published up to December 2024. The inclusion criteria comprised studies evaluating only randomized clinical trials that evaluated implant-supported monolithic restorations directly compared to metal-ceramic restorations, considering any type of ceramic material and regardless of the fixation system (screw-retained or cemented), with a minimum follow-up of one year. A meta-analysis was performed using RevMan 5.4 software, and the risk of bias and certainty of evidence were assessed using the RoB 2.0 and GRADE tools, respectively. A total of six studies were included, all of which exclusively evaluated monolithic zirconia single crowns over follow-up periods ranging from 1 to 3 years. None of the included studies evaluated fixed partial dentures or restorative materials other than monolithic zirconia. In total, 267 patients (mean age range: 18–57 years) were analyzed, with a total of 174 implant-supported monolithic zirconia crowns and 165 metal-ceramic single crowns in the posterior region (premolars and molars). The meta-analysis revealed that implant-supported monolithic zirconia single crowns exhibited significantly fewer prosthetic complications compared to metal-ceramic single crowns (p < 0.0001; Risk Ratio [RR]: 0.26; Confidence Interval [CI]: 0.14–0.47). However, no statistically significant differences were observed between implant-supported monolithic zirconia and metal-ceramic single crowns regarding implant survival rates (p = 0.36; RR: 1.66; CI: 0.56–4.94) or marginal bone loss (p = 0.15; Mean Difference [MD]: −0.05; CI: −0.11–0.02). The risk of bias assessment indicated that four studies had a low risk of bias. However, the certainty of evidence was classified as low for prosthetic complications and implant survival rates and very low for marginal bone loss. Within the limitations of this review, it can be concluded that implant-supported monolithic zirconia single crowns can be considered a favorable treatment option as they show comparable implant survival and bone stability to metal-ceramic crowns, with a potential reduction in short-term prosthetic complications such as screw loosening and ceramic chipping. However, due to the limited number of studies included and low certainty of evidence, further long-term research is still needed to confirm their clinical performance over time. Full article

Background: The main objective of this study was to carry out an online questionnaire in order to assess dentists’ knowledge and perception of dental materials submitted to high temperatures, helping to clarify and raise awareness of possible gaps in the area of forensic dentistry, especially in human identification. Results: Out of a total of 272 respondents, there was a greater influx of responses from countries such as Portugal and Brazil, the majority being female (66.3%), with an average age of 39 years. Most dentists consider complete clinical records to be extremely important. In addition, professionals with less experience provide fewer models in releasing their clinical records. In the case of dental materials, dentists consider composite resin and glass ionomers to be more susceptible to changes in shape and colour, while amalgam is considered the most stable, followed by ceramic and metal-ceramic crowns. On the other hand, dentin is considered more susceptible to colour changes than enamel. Enamel is seen by most professionals as resistant, undergoing few changes in shape at high temperatures. Conclusions: The opinion of the surveyed dentists on this subject is broadly in line with the existing literature. The only observed differences were related to exposure time and enamel resistance, since they assume that enamel is more resistant, and dentin is more vulnerable. Full article

Metal-ceramic crowns and bridges provide a stable and aesthetic tooth reconstruction. Hot pressing of veneering ceramics to metal substructure minimizes the formation of pores. Within the oral cavity, prosthetic structures are exposed to thermal stress. The study examines the influence of temperature changes on the quality and durability of the metal-ceramic bond using thermocyclic loading. Prior to the ceramic pressing, 40 cylindrical alloy specimens (height: 15 mm, diameter: 7 mm) were treated with abrasive blasting using Al₂O₃ (250 µm) or SiC (250 µm). They were divided into four groups: two control groups (sandblasted with Al₂O₃ or SiC) and two groups subjected to thermocyclic simulation. The ceramic-to-metal bond strength was measured with a shear test before and after thermocyclic loading. A statistically significant reduction in the bond strength between the metal substructure and the pressed ceramic was found after thermocyclic exposure. The bond strength decreased by 57% for Al₂O₃ sandblasted specimens and 36% for those sandblasted with SiC, as against the control group. This indicates that thermocycling weakens the bond between the metal alloy and pressed ceramic. The SiC blasting of the cobalt-chromium alloy results in a higher shear bond strength of the material connection after thermocyclic stimulation than the abrasive blasting with Al₂O₃. Full article

Background: The present article describes a step-by-step maximally digitalized workflow protocol with computer-aided design and computer-aided manufacturing (CAD/CAM) in partial-arch edentulous patients rehabilitated with fixed dental prostheses and removable partial dentures (FDPs and RPDs). Methods: Facial digitalization, intraoral scans, and functional mandibular movement recordings were used to create a 4D virtual patient on commercially available CAD software. The fixed components including post-and-cores, both metal–ceramic with extra-coronal attachment and monolithic zirconia crowns, and the RPDs were manufactured by computer numerical controlled direct milling. Results: This innovative digital approach using the virtual patient and the superimposition of interim RPDs fitted in the mouth has been used to provide fixed and removable rehabilitation to the patient without clinical complications with 2 years of follow-up. Conclusions: Within the limitations of this report, the developed combined prosthesis fabrication technique allowed optimization of the production by decreasing the clinical steps and laboratory procedures in partial-arch edentulous rehabilitated with FDPs and RPDs. Full article

Fracture resistance is an important parameter used to predict the performance of indirect dental restorations. The purpose of this in vitro study was to assess the fracture load of posterior milled nanoceramic crowns, in comparison with the lithium disilicate crowns, after fatigue loading, for two different restoration occlusal thicknesses. Forty test metal dies were fabricated by duplicating a master metal model consisting of an anatomic abutment preparation of the maxillary first premolar for a single crown. The dies were divided into two groups of 20 each for the fabrication of nanoceramic (Lava Ultimate) and lithium disilicate (IPS e.max CAD) single crowns. Each material group was further divided into two sub-groups of 10 dies each, based on crown occlusal thickness, of 0.5-mm and 0.75-mm (n = 10). Dental Type V stone dies poured from polyvinyl siloxane impressions of the test metal dies were laboratory scanned in order to design and mill 40 ceramic crowns. The crowns were cemented on to the test metal dies with a self-adhesive resin luting cement. All crowns were thermocycled (2500 cycles) and mechanically loaded (250,000 cycles) in a chewing simulator followed by static loading until failure, and the values noted. The data were statistically analyzed by 2-way ANOVA and Tukey HSD post-hoc multiple comparison tests (α = 0.05). The mean fracture loads ranged from 1022 to 1322 N for nanoceramic crowns and from 1145 to 1441 N for the lithium disilicate crowns. Two-way ANOVA revealed insignificant differences between the nanoceramic and lithium disilicate crowns (p > 0.05) in terms of fracture load. Significant differences were noted in the fracture resistance of crowns based on occlusal thickness (303 N; p = 0.013) regardless of the material used. Multiple comparisons by Tukey HSD post-hoc test showed insignificant differences between the four material-occlusal thickness groups (p > 0.05). The nanoceramic crowns were found to be comparable with lithium disilicate crowns in terms of fracture load. The mean fracture loads of all of the tested crowns were within the normal physiological masticatory load limits. Based on the fracture-resistance results, nanoceramic crowns seem to be suitable for clinical use for the tested occlusal thicknesses. Full article

Wirobond^® C is a commercial dental casting alloy suitable for the fabrication of crowns, bridges, and metal ceramic restorations. This study aims to investigate the effect of ready-to-use Listerine^® and Meridol^® mouthwashes and sodium fluoride on the resistance of CoCrMo dental alloys to electrochemical corrosion in artificial saliva at 37 °C. SEM, EDS, SKP, and microhardness investigations were carried out to characterize the material under study. The in vitro corrosion resistance of the CoCrMo alloy was conducted using the open-circuit potential method, electrochemical impedance spectroscopy, and anodic polarization curves. The presence of Co 59.8(8) wt.%, Cr 31.5(4) wt.%, and Mo 8.8(6) wt.% was confirmed. The CoCrMo alloy was characterized by a Vickers microhardness value of 445(31) µHV_0.3. Based on the EIS data, the capacitive behavior and high corrosion resistance of the CoCrMo alloy were revealed. The kinetics of pitting corrosion in the artificial saliva were lower after being modified with NaF, Listerine^®, and Meridol^® mouthwashes. The potentiodynamic characteristics revealed the passive behavior of the CoCrMo alloy in all solutions. Based on the SKP measurements of the CoCrMo alloy after corrosion tests, the effect of artificial saliva modification on the electronic properties of Bego Wirobond^® C dental alloy was found. Full article

As cementation represents the last stage of the work involved in making various indirect restorations (metal ceramic crowns and bridges, full ceramic crowns and bridges, inlays, onlays, and fiber posts), its quality significantly contributes to the clinical success of the therapy performed. In the last two decades, the demand for ceramic indirect restorations in everyday dental practice has considerably increased primarily due to the growing significance of esthetics among patients, but also as a result of hypersensitivity reactions to dental alloys in some individuals. In this context, it is essential to ensure a permanent and reliable adhesive bond between the indirect restoration and the tooth structure, as this is the key to the success of aesthetic restorations. Resin-based luting materials benefit from excellent optical (aesthetic) and mechanical properties, as well as from providing a strong and durable adhesive bond between the restoration and the tooth. For this reason, resin cements are a reliable choice of material for cementing polycrystalline ceramic restorations. The current dental material market offers a wide range of resin cement with diverse and continually advancing properties. In response, we wish to note that the interest in the properties of resin-based cements among clinicians has existed for many years. Yet, despite extensive research on the subject and the resulting continued improvements in the quality of these materials, there is still no ideal resin-based cement on the market. The manuscript authors were guided by this fact when writing the article content, as the aim was to provide a concise overview of the composition, properties, and current trends, as well as some future guidelines for research in this field that would be beneficial for dental practitioners as well as the scientific community. It is extremely important to provide reliable and succinct information and guidelines for resin luting materials for dental dental practitioners. Full article

The usage of monolithic zirconia has been increasing in daily practice in dentistry for the last 20 years. Monolithic zirconia is mainly used for posterior sector rehabilitation, as it lacks optical properties and has good technical properties; it does not chip and reduces antagonist wear compared to metal–ceramic prostheses. However, monolithic zirconia may present some issues, mainly low-temperature degradation (LTD), also known as “aging”, which must be considered and investigated in clinical studies with prolonged follow-up periods. The aim of this study was the aesthetic and functional evaluation of single monolithic zirconia crowns that were screwed onto implants for posterior dental rehabilitation using USPHS parameters and a long follow-up period of 7 years. The results showed that the USPHS scoring reduces year by year, passing from 100% excellence between the first and fourth years of observation, to 88% excellence and 12% success in the seventh year. Screw abutment loosening was the only technical adversity reported; no implant failure, crown fracture, or irreparable damage were additionally registered. Considering the emerging results and comparing them with the data available in the literature, the authors suggest that monolithic zirconia crowns could be considered as a valid alternative to classic metal–ceramic rehabilitations for the rehabilitation of posterior sectors. Full article

Metal-ceramic crowns (MC) have long been considered as gold standard for dental prosthetic restorations. Our study aims to evaluate the influence of MC, with conventional technology used for the framework, on the periodontal parameters and levels of C reactive protein, an inflammatory marker, in gingival crevicular fluid in patients diagnosed with periodontitis. Two groups were established: the test group T-28 teeth from the lateral area wearing a MC crown and the control group C-28 teeth without any wearing. These parameters were evaluated: probing depth, Gingival Index, and longevity of crowns. The quantitative assessment through enzyme-linked immunosorbent assay of the targeted pro-inflammatory mediator was performed. There is a difference statistically significant between the groups T and C regarding the marker’s levels and gingival index, a very strong correlation between these levels and probing depth and a strong correlation between longevity and Gingival Index. Periodontal clinical parameters are more pronounced the longer the time elapsed since the application of the crowns. Expression of C reactive protein is higher in the presence of MC crowns. Full article

Background. CAD/CAM technologies facilitate using powder CoCr alloys to produce metal-ceramic dental restorations. However, base alloys may induce oxidative stress in the oral cavity due to corrosion and ion release. This study evaluated resistance to corrosion and release of metal ions from 3D printed CoCr dental alloy and their effect on oral oxidative stress. Methods. Metal-ceramic crowns with 3D printed copings from CoCr alloy EOS CobaltChrome SP2 (EOS, Germany) were fabricated for 35 patients. Inductively coupled plasma mass spectrometry (ICP-MS) was used for measuring the concentration of Co and Cr ions in non-stimulated saliva before prosthetic treatment (BPT), at 2 h and 7 days after the dental treatment (APT2, APT7, respectively). Open circuit potentials (Eocp) were evaluated at APT2 and APT7. Estimating oral oxidative stress, measurements of 8-isoprostaglandin F2-alpha were conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS) at stages BPT, APT2, and APT7. Results. Salivary Co level increased at APT2 and decreased to the initial levels at APT7. No statistical difference was found between the levels of 8-isoPGF2-alpha measured, and between the Eocp measurements at APT2 and APT7. Conclusions. The studied alloy showed stable corrosion resistance and the metal ion release did not induce oral oxidative stress. Full article

Background: The objective of this study was to evaluate the load transmitted to the peri-implant bone by seven different restorative materials in single-unit rehabilitations with morse taper implants using a strain gauge. Materials: In a polyurethane block that simulated type III bone, a morse taper platform implant was installed (3.5 × 11 mm) in the center and 1 mm below the test base surface, and four strain gauges were installed around the implant, simulating the mesial, distal, buccal and lingual positions. Seven similar hybrid abutment crowns were crafted to simulate a lower premolar using different materials: 1—PMMA; 2—glass ceramic over resin matrix; 3—PEEK + lithium disilicate; 4—metal–ceramic; 5—lithium disilicate; 6—zirconia + feldspathic; 7—monolithic zirconia. All groups underwent axial and oblique loads (45 degrees) of 150 N from a universal testing machine. Five measurements (n = 5) were performed with each material and for each load type; the microdeformation data underwent statistical analysis. The data were obtained in microdeformation (με), and the significance level was set at p ≤ 0.05. Results: There was no statistically significant difference in the evaluation among the materials under either the axial load or the oblique load at 45 degrees. In turn, in the comparison between axial load and oblique load, there was a difference in load for all materials. Conclusion: The restorative material did not influence the load transmitted to the bone. Furthermore, the load transmitted to the bone was greater when it occurred obliquely at 45° regardless of the material used. In conclusion, it appeared that the different elastic modulus of each material did not influence the load transmission to the peri-implant bone. Full article

Retention and support are needed for removable partial denture stability. The stability can be achieved by clasps, occlusal and cingulum rests on healthy abutment teeth. However, implants or crowns can be used to support the removable partial denture instated on unhealthy abutment teeth. This study was conducted to investigate the fracture strength of two types of all-ceramic restorations used as abutments for the removable partial denture framework. The crowns were manufactured with two types of ceramic materials: zirconia and IPS e.max Press ceramics. The metal alloy (cobalt-chrome) was cast to form the removable partial denture framework. A universal testing machine was used to evaluate the fracture strength of both ceramic crown materials. The results presented no fractures in all-ceramic crowns, but deformation of the partial denture frameworks occurred. With the limitation of this study, it can be concluded that zirconia and IPS e.max Press ceramic can be used as abutments to provide adequate support to the removable partial denture. Full article

The conventional metal–ceramic is still considered the gold standard in fixed prosthetics especially in terms of longevity. Among alternative materials used, Monolithic Zirconia has shown the capability to reconcile excellent biomechanical properties with acceptable aesthetic performance and to overcome several inconveniences related to veneer restorations. This study aims to clinically evaluate Monolithic Zirconia prosthetic crowns on natural abutments in the posterior sectors, performed by final-year dental medicine students (undoubtedly with less experience in the management of such material) by the standardized California Dental Association score system evaluation, to better understand the viability of Monolithic Zirconia. This prospective study was carried out at the Dental School of the University of Bari “Aldo Moro”, Italy. Prosthetic rehabilitation included single crowns or a short pontic prosthesis with maximum one intermediate. Final-year dental students performed tooth reduction under the supervision of three expert tutors. The California Dental Association systematics (based on color, surface, anatomical shape, and marginal integrity) were adopted to evaluate the prosthetic maintenance status over time. Annual follow-up visits were re-evaluated by the same parameters each year. Univariate logistic regression analysis was performed to evaluate outcomes and the Kaplan–Meier plot to report survival. The sample consists of 40 crowns performed on 31 patients, 15 males (48.4%) and 16 females (51.6%) with an average age of 59.3 years. The clinical cases subjected to experimental study were found to be “Excellent” (1a/2a/3a/4a) in 34 cases (85%), “Acceptable” in 4 cases (10%), and “To be re-done” in 2 cases (failures) (5%). Our conclusive data support the predictability of Monolithic Zirconia restorations on natural posterior abutments at a long-term follow-up of five years, even when performed by less-experienced clinicians. Full article