Fixed Dental Prostheses Research Articles

Comparative Analysis of the Fracture Resistance of a Polymeric Material for 3D Printing and a Milled Polymethylmethacrylate Material as Interim Material for Fixed Partial Dentures: New Material Updated

The aim of this study was to evaluate and compare the fracture resistance of a temporary three-unit fixed dental prosthesis (FDP) made of a new polymeric material obtained by an additive technique (3DPP) using a computer-aided design and manufacturing (CAD/CAM) system, comparing the prosthesis to the respective outcomes of temporary polymethylmethacrylate (PMMA) FDPs obtained by a subtractive technique (milling). Methods: Three-unit FDPs were 3D printed using a polymeric material (n = 20) or milled using polymethylmethacrylate (n = 20). After thermocycling at 5000 cycles at extreme temperatures of 5 °C and 55 °C in distilled water, each specimen was subjected to a compression test on a universal testing machine at a rate of 0.5 mm/min until failure occurred, recording the value in newtons (N). Results: There were statistically significant differences (p-value < 0.005) between the PMMA material (2104.7 N; SD = 178.97 N) and 3DPP (1000.8 N; SD = 196.4 N). Conclusions: The fracture resistance of the PDFs manufactured from milled PMMA showed higher values for fracture resistance. However, the resistance of the 3DPP showed acceptable values under mechanical load; this notable advance in the resistance of printed materials consolidates them as an important alternative to use in interim indirect restorations.

A guide for selecting the intraoral scan extension when fabricating tooth- and implant-supported fixed dental prostheses.

To describe a new classification for intraoral scans based on the scan extension and to introduce a decision guideline to choose the scan extension for fabricating tooth- and implant-supported fixed dental prostheses (FDPs). Multiple operator- and patient-related factors have been identified that can decrease the scanning accuracy of intraoral scanners (IOSs), including scan extension. However, the decision criteria for selecting scan extension for fabricating tooth- and implant-supported restorations is unclear. Based on the extension of the intraoral digital scans, three types of scans can be defined: half-arch (anterior or posterior), extended half-arch, and complete-arch scan. Variables to consider when choosing the scan extension include the number and location of units being restored, as well as the extension and location of edentulous areas. Additionally, the accuracy of the virtual definitive cast and the accuracy of the maxillomandibular relationship captured by using IOSs should be differentiated. A decision tree for selecting the scan extension is presented. The decision is based on the number and location of units being restored, and the extension and location of edentulous areas. Intraoral scans with reduced scan extension are indicated when fabricating tooth- and implant-supported crowns or short-span fixed prostheses, when the patient does not have more than one missing tooth in the area of the dental arch included in the scan. For the remaining clinical conditions, complete-arch intraoral scans are recommended. Scan extension is a clinician's decision that should be based on the number and location of units being restored and the extension and location of edentulous areas. Intraoral scans with a reduced scan extension is recommended, when possible.

Prospective evaluation of implants-supported, tooth-implant supported, and teeth-supported 3-unit posterior monolithic zirconia fixed restorations: Bite force and patient satisfaction.

This study aimed to evaluate the maximum bite force (MBF) and satisfaction of patients restored with implants, combined tooth-implants, and teeth-supported monolithic zirconia fixed dental prostheses (FDPs). Thirty partially edentulous patients in need of three units of FDPs in their mandibular posterior region were divided into three equal groups (n = 10) as follows: Group-1 patients received two implants for each at the second premolar and second molar regions, Group-2 patients received one implant for each at the second molar region, and Group-3 patients with missing lower first molar. All the restorations were constructed from monolithic zirconia. Patients were evaluated 1 week after placement of restorations (baseline) and then after 6, 12, and 24-month intervals for MBF using force transducer occlusal force meter and satisfaction (function, esthetic, and overall satisfaction) using a visual analog scale. The mean MBF for Group 1 was higher than Group 2 (p = .044) but not that of Group 3 (p = .923). Additionally, Group 3 displayed a higher MBF than Group 2, although this difference was not statistically significant (p = .096). Concerning patient satisfaction, all study groups reported high levels of satisfaction across all satisfaction elements, and no significant differences were observed between the groups. Within the limitations of this study, it can be concluded that Group 1 gives comparable anticipated treatment outcomes as Group 3 concerning biting force and patient satisfaction. However, Group 2 gives comparable satisfaction results with biting force value within the normal range; thus, it might be used as a treatment option in a specific situation.

Rehabilitation of Deep Bite with Dental Implants and Fixed Dental Prostheses: A Case Report

Rehabilitation of patients having deep bite are restored either with tooth supported fixed prosthesis, implants prosthesis or by a combination of both. Implant retained fixed bridges range from limited span to complete arch for dentulous and edentulous jaws. The desire to achieve expected results has in the long-run involved several issues concerning the materials, techniques and anchorages used. In respect to the types of connection between the implant and restoration, these can be screwed, cemented, or a technique combining both can be implemented. The purpose of this article is to describe an impression technique and its various procedures for rehabilitation of a patient with deep bite using tooth and implant supported prosthesis.

Fit of High-Translucency Zirconia Fixed Dental Prostheses Using Two Different Intraoral Scanners.

To assess the marginal and internal fit of monolithic zirconia fixed dental prostheses (FDPs) comparing two different intraoral scanners (IOSs) and assessment methods. A maxillary typodont with three prepared teeth allowed fabrication of five-unit high-translucency monolithic zirconia FDPs. The typodont was scanned with two IOSs: Cerec Omnicam and 3Shape TRIOS 3. In total, 30 FDPs were milled from presintered high-translucency zirconia blocks. Dual-scan and silicone replica assessments were used to determine marginal and internal gaps. A statistical significance was observed for marginal gaps (3Shape [74.27 ± 10.4 μm] and Cerec [86.45 ± 14.3 μm]) and for internal gaps (3Shape [126.12 ± 12.7 μm] and Cerec [112.38 ± 17.2 μm]). The outcomes of this study showed that the 3Shape TRIOS 3 produced a better overall marginal fit, while the Cerec Omnicam created a better internal fit. Additionally, a greater overall marginal and internal gap was noted with the silicone replica method over the dual-scan method.

Technical complications with tooth-supported fixed dental prostheses (FDPs) of different span lengths: an up to 15-year retrospective study

BackgroundsLong-span dental bridges may cause excessive load on abutment teeth and the periodontal area, which may lead to bridge fractures or periodontal problems. However, some reports have revealed that short- and long-span bridges can provide a similar prognosis. This clinical study aimed to investigate the technical complications associated with fixed dental prostheses (FDPs) of different span lengths.MethodsAll patients with previously cemented FDPs were clinically examined during their follow-up visits. Several data related to FDPs were registered, such as design, material type, location, and type of complication. The main clinical factors analyzed were technical complications. Life table survival analyses were performed to calculate the cumulative survival rate of FDPs when technical complications were detected.ResultsThe study examined 229 patients with a total number of 258 prostheses and an average of 98 months of follow-up. Seventy-four prostheses suffered from technical complications, and the most common complication was ceramic fracture or chipping (n = 66), while loss of retention occurred in 11 prostheses. The long-term evaluation of long-span prostheses revealed a significantly higher technical complication rate compared to short-span prostheses (P = ,003). The cumulative survival rate for short-span FDPs was 91% in year 5, 68% in year 10, and 34% in year 15. For long-span FDPs, the cumulative survival rate was 85% in year 5, 50% in year 10, and 18% in year 15.ConclusionLong-span prostheses (5 units or more) can be associated with a higher technical complication rate compared to short-span prostheses after long-term evaluation.

A Retrospective Clinical Evaluation Of Narrow Diameter Implant Supported Dental Prosthesis: Early Results

Background: Narrow-diameter implants are planned for specific clinical conditions as locator implants between adjacent teeth with a narrow bone width or with only a narrow area in between. They are especially advantageous when restoring narrow teeth like lateral maxillary and mandibular incisors and first premolars.
 Methods: In the period between 2018 and 2019, 21 patients were rehabilitated with implant treatment. A total of 32 implants were placed (The Straumann® Bone Level Tapered Implants, ∅ 2.9 mm). The survival rates of the implants were analyzed and prosthetic complications were evaluated.
 Results: The accumulative 36-month survival rate of the implants was 96.9%. Prosthetic complications were mainly limited to loosening occlusal screws. No implant abutment fractures, screw fractures, or porcelain chipping were observed.
 Conclusion: The results show that narrow implants provide satisfactory treatment outcomes. Narrow implants can be preferred in cases, where the dental operation area is not wide enough.
 Keywords: Narrow Diameter Implants, Fixed Dental Prosthesis, Survival Rate.

Effect of non-rigid connector on the stress distribution of tooth-implant supported fixed prostheses using different implant length and diameter: A comparative 3D finite element study.

To investigate the significance of the connector type on stress dissemination within the tooth-implant-supported fixed dental prostheses in the mandibular posterior region with different combinations of implant diameter and length by means of finite element analysis (FEA). Six models of different designs for tooth-implant fixed dental prosthesis (FDPs)were simulated and divided into two main groups. Implant lengths were 10, 11.5, and 13mm while implant diameters were 3.7, 4.7, and 5.7mm. The main difference between the groups was the connector type. Models were evaluated using 3D FEA (Solidworks Premium 2018 × 64 Edition). Group A tooth-implant FDPs (5.7mm × 10 mm) had a mesial and distal rigid connector while group B tooth-implant FDPs (3.7mm × 10mm, 3.7mm × 11.5mm, 3.7mm × 13mm, 4.7mm × 10mm and 5.7mm × 10mm) had a mesial non-rigid connector in their design between the pontic and the tooth. Models were analyzed to determine the magnitude of von Misses Stresses at six specific zones (fixed dental prosthesis, bone around distal implant, bone around tooth, cementum, periodontal ligament, implant) under vertical occlusal loading of 100 N after meshing and assigning the material properties. Stress values around the supporting bone were significantly higher in Group B (tooth-implant FDP with non-rigid connection) when compared to Group A (tooth-implant FDP with rigid connection). Also, the stresses measured at the FDP level showed that the rigid connection group (5.7 mm × 10mm) exhibited 26% lower stress values when compared to the non-rigid group (5.7 mm × 10mm). Implant-tooth FDPs with rigid connector design using the combination of implant diameter and length (5.7mm × 10mm) demonstrated a better design modality thus predicting a higher success rate and more longevity than using the non-rigid connection option.

Water temperature for fabrication of autopolymerizing polymethyl methacrylate (PMMA) interim fixed restoration affects cytotoxicity and residual methyl methacrylate (MMA)

Background/purposeClinically, dentists are suggested to immerse autopolymerizing interim fixed restorations in hot water during fabrication. However, this suggestion, without including the best temperature, mostly comes from clinical experience instead of scientific evidence. This in vitro study evaluated the effect of water temperature on the cytotoxicity of interim partial fixed dental prostheses (FDPs) and examined its correlation with residual MMA. Materials and methodsTempron was chosen as the autopolymerizing polymethyl methacrylate material. Tempron was mixed and then soaked in water at different temperatures, except control group (Controlair) was not being soaking in water. The specimens were incubated with conditioned medium. The concentration of residual MMA was determined by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The cell viability of human gingival fibroblasts (HGFs) was evaluated by MTT assay. ResultsThe 60 °C and 80 °C groups exhibited significantly higher cell viabilities than those of the other groups (P < 0.05) at 48 and 72 h. The concentration of residual MMA was highly correlated with this outcome: the higher the concentration of residual MMA detected in the eluates, the poorer the cell viability was; the longer the incubation time was, the stronger the correlation was between the concentration of residual MMA and the cell viability. ConclusionAutopolymerizing PMMA interim FDPs that are polymerized in water up to at least 60 °C could reduce cell toxicity. Higher water temperature could certainly decrease the amount of residual MMA, which is closely correlated with the outcome of cell viability.

Screw Retained Implant Supported Zirconia Anterior Fixed Dental Prosthesis with Different Abutment Angulations: Evaluation of Fracture Resistance and Failure Modes

Screw Retained Implant Supported Zirconia Anterior Fixed Dental Prosthesis with Different Abutment Angulations: Evaluation of Fracture Resistance and Failure Modes

Mechanical Properties of Three-Dimensional Printed Provisional Resin Materials for Crown and Fixed Dental Prosthesis: A Systematic Review.

The emergence of digital dentistry has led to the introduction of various three-dimensional (3D) printing materials in the market, specifically for provisional fixed restoration. This study aimed to undertake a systematic review of the published literature on the Mechanical Properties of 3D- Printed Provisional Resin Materials for crown and fixed dental prosthesis (FDP). The electronic database on PubMed/Medline was searched for relevant studies. The search retrieved articles that were published from January 2011 to March 2023. The established focus question was: "Do provisional 3D-printed materials have better mechanical properties than conventional or milled provisional materials?". The systematically extracted data included the researcher's name(s), publication year, evaluation method, number of samples, types of materials, and study outcome. A total of 19 studies were included in this systematic review. These studies examined different aspects of the mechanical properties of 3D-printed provisional materials. Flexural Strength and Microhardness were the frequently used mechanical testing. Furthermore, 3D-printed provisional restorations showed higher hardness, smoother surfaces, less wear volume loss, and higher wear resistance compared to either milled or conventional, or both. 3D-printed provisional resin materials appear to be a promising option for fabricating provisional crowns and FDPs.

Fracture Load of Veneered and Monolithic Single-Unit Fixed Dental Prostheses Made from the High-Performance Thermoplastic Polyphenylene Sulfone

To investigate the fracture load of different veneers for monolithic single-unit fixed dental prostheses (FDPs) made of a novel potential framework material, polyphenylene sulfone (PPSU). The fracture loads of four PPSU frameworks with different veneers (manual polymer veneer with Ceramage Body A3B; prefabricated polymer veneer with Novo.lign; digital polymer veneer with Telio CAD; digital ceramic veneer with IPS Empress CAD) and a monolithic control group (PPSU, Gehr) were examined initially and after 1,200,000 masticatory (50 N, 1.3 Hz) and 6,000 thermal cycles (5°C/55°C). Fracture analysis was performed using light microscope imaging. Fracture types were classified, and relative frequencies were determined. Univariate analysis of variance, post hoc Scheffé, partial eta squared, Kruskal-Wallis test, and Weibull moduli using the maximum likelihood estimation method were calculated. The defined level of significance was adjusted by Bonferroni correction (P < .005). Aging did not affect the fracture load values. Single-unit FDPs with a digital ceramic veneer showed lower values than monolithic and manual polymer-veneer specimens. Single-unit FDPs with a prefabricated and digital polymer veneer were in the same value range as specimens with a manual polymer and digital ceramic veneer. No differences were observed between manual polymer veneer and monolithic single-unit FDPs. All veneered specimens showed a fracture of the veneer. For monolithic single-unit FDPs, a plastic deformation was observed. Veneered and monolithic PPSU showed sufficient fracture load values to indicate successful clinical use in single-unit FDPs. The choice of veneering method and material may play a minor role.

Facially Driven Rehabilitation of a Cleft Lip and Palate Patient with an Implant-Supported Complete Fixed Dental Prosthesis: Outcome of a Multidisciplinary Approach.

Patients with a facial malformation due to a cleft lip and palate (CLP) usually suffer from a reduced ability to function normally associated with a poor oral health-related quality of life. This condition often requires multiple significant surgical interventions, and the prosthetic restoration, when needed, is not always included in the initial treatment plan. In order to obtain the highest possible degree of functional, occlusal, and phonetic performance, as well as esthetics, a facially guided prosthodontic treatment sequence should be established. The case presented in this publication shows a multidisciplinary approach for reconstruction of a compromised maxilla with an implant-supported prosthesis via a minimally invasive, digitalized approach.

Fracture Resistance Analysis of CAD/CAM Interim Fixed Prosthodontic Materials: PMMA, Graphene, Acetal Resin and Polysulfone

Four groups of ten samples were fabricated for each material. Each specimen was characterized by a compression test on a universal testing machine, all specimens were loaded to fracture and the value in Newtons (N) was recorded by software connected to the testing machine. The fracture mode was evaluated on all samples using a stereomicroscope. There were statistically significant differences (p value < 0.005) between PMMA and the other three materials (PMMA: 1302.71 N; GRA: 1990.02 N; RA: 1796.20 N; PS: 2234.97). PMMA presented a significantly lower value than the other materials, and PS showed the highest value. GRA and RA presented a similar range of values but they were still higher than those of PMMA. GRA, RA and PS are presented as valid options within the range of interim milled restorative materials and as alternatives to PMMA.

Stress Distribution in Implant-Supported Fixed Dental Prosthesis (Pontic Design) using Two Different Framework Materials: A Finite Element Analysis

Aim and Objectives: The stresses transferred from the implant to the surrounding bone greatly influence the clinical outcome of the implant-supported prosthesis. The role of implant-supported prostheses made from zirconia and polyether ether ketone (PEEK) material in transferring stresses is not much known. The purpose of the finite element analysis study was to evaluate stress distribution in an implant-supported fixed dental prosthesis (FDP) using two different framework materials. Materials and Methods: Two three-dimensional models of implant-supported FDPs were designed using ANSYS software, with implants in right maxillary central incisor and canine regions supporting a three-unit fixed partial denture. Model 1 was made using zirconia as a framework material and model 2 using PEEK as a framework material. A static load of 100 N was applied in two directions, i.e., vertically and obliquely at an angle of 30° along the long axis of the implant. The von Mises stress analysis was done to find stresses generated in implants and the prosthesis, and the maximum and minimum principal stress analyses were used to find the stress generated in the bone. Results: Under both the loading conditions, maximum stress concentration was observed in the connector region of model 1 (zirconia group) compared to model 2 (PEEK group); 6.28 MPa versus 2.17 MPa in vertical loading and 8.85 MPa versus 2.69 MPa in oblique loading, respectively. The stresses generated in bone were nearly similar in both models. Conclusion: The framework material does affect the load-bearing capacity of the prosthesis. Stresses observed with PEEK as framework material were lesser compared to zirconia. Therefore, PEEK can be considered a suitable framework material for implant-supported FDPs.

Restoration of Missing Central Incisor with Cantilevered Zirconia Resin Bonded Fixed Dental Prosthesis

Missing teeth in the anterior region can be a source of great aesthetic concern for the patient and its restoration presents an even greater challenge to the dentist. Invasive prosthodontic treatment modalities have many biological and biomechanical shortcomings. This clinical report presents a minimally invasive treatment option for a 17-year-old boy who wanted a replacement for his missing upper left central incisor, primarily due to aesthetic concerns. Missing tooth was restored with cantilevered zirconia resin bonded fixed dental prosthesis that has a durable functional and aesthetic outcome

The Effect of Dentine Desensitizing Agents on the Retention of Cemented Fixed Dental Prostheses: A Systematic Review

Background and Objectives: The use of desensitizing agents (DA) after tooth preparation to prevent hypersensitivity is well documented in the literature. A fixed dental prosthesis (FDP) should have good retention to be successful. Inadequate retention may result in microleakage, secondary caries, and, eventually, dislodgement of the FDP. The effect of DAs on the retention of FDPs has been widely studied in the literature, but the results are conflicting. Thus, this study aimed to conduct a systematic review to assess the effect of dentine desensitizing agents, used to prevent post-cementation hypersensitivity, on the retention of cemented FDPs. The null hypothesis framed was that there is no effect of dentine desensitizing agents on the retention of cemented FDPs. The focused PICO question was as follows: "Does the application of dentine desensitizing agents (I) affect the retention (O) of cemented fixed dental prosthesis (P) when compared to non-dentine desensitizing groups (C)"? Materials and Methods: Four electronic databases were systematically searched and, on the basis of the predefined inclusion and exclusion criteria, 23 articles were included in this systematic review. A modified CONSORT scale for in vitro studies was used to assess the quality of the selected studies, as all included studies were in vitro studies. Results: Most of the studies compared the effect of more than one type of DA on retention. The results of the selected studies varied due to differences in the composition of tested dentine DAs and types of luting cements. Conclusions: Within the limitations of this study, it can be concluded that the retention values of FDPs cemented using zinc phosphate cement were reduced with most of the DAs, whereas retention values increased when GIC, resin-modified GIC, and resin cements were used with the majority of DAs. These findings are important, as they can guide dentists in selecting the DA before cementing the crowns with the luting agent of their choice, without compromising the retention of the crowns.

Marginal Fit, Mechanical Properties, and Esthetic Outcomes of CAD/CAM Interim Fixed Dental Prostheses (FDPs): A Systematic Review

This systematic review aimed to study the outcomes of CAD-CAM (milled and 3D-printed) interim dental prostheses when compared to conventional ones. The focused question of "In natural teeth, what are the outcomes of CAD-CAM interim FDPs compared to the conventionally-manufactured ones regarding marginal fit, mechanical properties, esthetics, and color stability" was formulated. The systematic search was conducted electronically in the PubMed/MEDLINE, CENTRAL, EMBASE, Web of Science, New York Academy of Medicine Grey Literature Report, and Google Scholar databases by using the MeSH keywords and keywords associated with the focused question and limiting articles to those published between 2000 and 2022. A manual search was conducted in selected dental journals. The results were analyzed qualitatively and are presented in table format. Of the included studies, 18 studies were in vitro and 1 was a randomized clinical trial. Of the eight studies analyzing the mechanical properties, five studies favored the milled interim restorations, one study favored both 3D-printed and milled interim restorations, and two studies reported better mechanical properties in conventional interim restorations. Among four studies evaluating the marginal discrepancies, two studies favored the marginal fit in milled interim restorations, one study reported a better marginal fit in both milled and 3D-printed interim restorations, and one study found conventional interim restorations have a better marginal fit and smaller marginal discrepancy when compared to both milled and 3D-printed restorations. Among five studies that evaluated both the mechanical properties and marginal fit, 1 study favored 3D-printed interim restorations and four studies favored milled interim restorations over the conventional ones. Two studies analyzing the esthetics outcomes demonstrated better results with milled interim restorations compared to conventional and 3D-printed interim restorations in terms of their color stabilities. The risk of bias was low for all the studies reviewed. The high level of heterogeneity within the studies excluded meta-analysis. Most of the studies favored the milled interim restorations over the 3D-printed and conventional restorations. The results suggested that milled interim restorations offer a better marginal fit, higher mechanical properties, and better esthetic outcomes in terms of color stabilities.

The Complete Digital Workflow in Fixed Prosthodontics Updated: A Systematic Review

Digital applications have changed therapy in prosthodontics. In 2017, a systematic review reported on complete digital workflows for treatment with tooth-borne or implant-supported fixed dental prostheses (FDPs). Here, we aim to update this work and summarize the recent scientific literature reporting complete digital workflows and to deduce clinical recommendations. A systematic search of PubMed/Embase using PICO criteria was performed. English-language literature consistent with the original review published between 16 September 2016 and 31 October 2022 was considered. Of the 394 titles retrieved by the search, 42 abstracts were identified, and subsequently, 16 studies were included for data extraction. A total of 440 patients with 658 restorations were analyzed. Almost two-thirds of the studies focused on implant therapy. Time efficiency was the most often defined outcome (n = 12/75%), followed by precision (n = 11/69%) and patient satisfaction (n = 5/31%). Though the amount of clinical research on digital workflows has increased within recent years, the absolute number of published trials remains low, particularly for multi-unit restorations. Current clinical evidence supports the use of complete digital workflows in implant therapy with monolithic crowns in posterior sites. Digitally fabricated implant-supported crowns can be considered at least comparable to conventional and hybrid workflows in terms of time efficiency, production costs, precision, and patient satisfaction.

Load bearing capability of three-units 4Y-TZP monolithic fixed dental prostheses: An innovative model for reliable testing

In this work, three-units monolithic fixed dental prostheses (FDPs) have been analysed and a novel model for reliable testing has been proposed. Such model is based on a new design of the polymeric base of the FDP, realised via additive manufacturing (AM) - a solution that conveys at the same time quick manufacturability, low cost, custom-ability, and design freedom. By means of this new model, the load-bearing capability of three-units monolithic FDPs has been thoroughly tested; in particular, three different analyses were performed: (i) analytical with a beam-like model, (ii) numerical, using non-linear three-dimensional Finite Elements (FE) models and (iii) experimental, by static bending test. The FDPs considered in this work were manufactured using a fourth-generation zirconia, namely 4Y-TZP. The findings demonstrated the undoubted advantages of the new base configuration, which minimized the effect of the base (which as a matter of fact is absent in in-vivo conditions) on the stress state of the connectors in the FDPs, and increased the repeatability and reliability of the experimental bending tests, able to determine the load bearing capability of the 4Y-TZP FDPs.