Removable Partial Denture Frameworks Research Articles

Effect Of Manufacturing Techniques On Adaptation Of Removable Partial Denture Frameworks In Mandibular Kennedy Class I cases: An In Vitro Comparative Study

Effect Of Manufacturing Techniques On Adaptation Of Removable Partial Denture Frameworks In Mandibular Kennedy Class I cases: An In Vitro Comparative Study

Non-metal framework for removable partial dentures – A 2-year follow-up clinical report

Traditional removable partial dentures (RPDs) with cobalt-chromium frameworks have been used for several decades, restoring the masticatory function. However, these frameworks have been documented as aesthetically unacceptable due to the display of metal clasps. The patients' increased demands regarding the aesthetic aspects of rehabilitation treatment led to the introduction of new, more aesthetic materials in clinical practice. One of the main materials is polyetheretherketone (PEEK). This clinical report presents PEEK as an alternative material for fabricating RPD frameworks for a Class III Kennedy partial edentulous mandible. The framework was constructed using CAD/CAM manufacturing, and the process combined laboratory scanning, digital framework design, resin try-in milling, and PEEK framework milling. The framework showed good adaptation to the abutment teeth and surrounding tissues. The patient was followed for 2 years without complaints and was grateful for the aesthetics. During this period, there were no signs of degradation in the framework, and the clasps were still as retentive as they were at the initial appointment, with only some pigmentation of the structure being observed.

Effect of finishing and polishing techniques on the fit accuracy and dimensions of conventional and CAD‐CAM removable partial denture frameworks

Effect of finishing and polishing techniques on the fit accuracy and dimensions of conventional and CAD‐CAM removable partial denture frameworks

Seating accuracy of removable partial denture frameworks fabricated by different digital workflows in comparison to conventional workflow.

To evaluate the seating accuracy of removable partial denture (RPD) frameworks fabricated by two digital workflows involving selective laser melting (SLM) in comparison to the conventional workflow. A Kennedy class III modification 1 partially edentulous mandibular arch was used as a master model. Three RPD framework groups were included: (1) a conventional workflow group with conventional impression and casting (CC), (2) a partial digital workflow group with conventional impression and digital fabrication (CD), and (3) a complete digital workflow group with digital impression and digital fabrication (DD). A total of 10 frameworks were produced for each group. The marginal gaps at the occlusal rests, retention arms, and reciprocating arms were measured by a traveling microscope. The data were analyzed with the one-way analysis of variance test. At the framework level, the most superior fit was observed for the CD group (79.5µm) followed by DD (85.3µm) and CC (114.2µm) groups. The CD and DD groups were significantly superior to CC (p<0.001). This fit pattern was consistent for the retention and reciprocating arms, while the occlusal rest fit was similar among all the groups. The SLM frameworks had a promising seating accuracy in comparison to conventional frameworks. The type of impression, conventional or digital, did not affect the accuracy of SLM frameworks. The differences observed in the present study are likely to be of minimal clinical significance.

Accuracy of Mandibular Removable Partial Denture Frameworks Fabricated by 3D Printing and Conventional Techniques.

Herein, we used digital superimposition to evaluate the accuracy of metal frameworks for mandibular removable partial dentures fabricated using three techniques. Thirty master casts of a mandibular dentiform were categorized into three groups (n = 10) based on the framework manufacturing method: selective laser melting-based metal three-dimensional (3D) printing (SLM), digital light projection-based resin 3D printing and subsequent casting (RPC), and conventional casting (CON). The master casts were scanned twice, initially after preparation and subsequently after attaching silicone using the frameworks. These scan files were digitally superimposed to measure the silicone thickness. Statistical analysis was conducted using SPSS Statistics (Version 23.0, IBM Corp., Somers, NY, USA). One-way ANOVA and a post hoc Tukey's multiple comparison tests were performed to determine differences among the three groups (α = 0.05). The RPC group exhibited significantly higher overall and mean internal discrepancies at rest and tissue stops than the SLM and CON groups, which exhibited statistically insignificant differences. Thus, SLM fabrication resulted in comparable accuracy to that achieved by CON, whereas sequentially performing resin 3D printing and casting induced inferior accuracy. However, all frameworks across the three groups were clinically acceptable.

Suitability and Trueness of the Removable Partial Denture Framework Fabricating by Polyether Ether Ketone with CAD-CAM Technology.

The object of the study was to evaluate the suitability and trueness of the removable partial denture (RPD) framework fabricated by polyether ether ketone (PEEK) with the CAD-CAM technology in vitro. Four different types of dentition defects were selected. In each type, five PEEK RPD frameworks were fabricated by the CAD-CAM technology, while five Co-Cr RPD frameworks were made by traditional casting. The suitability of the framework was evaluated by silicone rubber film slice measurement and the three-dimensional image overlay method. The trueness of the PEEK framework was detected by the three-dimensional image overlay method. Data were statistically analyzed with the use of an independent samples t-test (α = 0.05). The suitability values by silicone rubber film slice measurement of the PEEK group were lower than those of the Co-Cr group in four types, with the differences indicating statistical significance (p < 0.05) in type one, type two, and type four. The suitability values using the three-dimensional image overlay method showed no statistical differences (p > 0.05) between the two groups in four types. The trueness values of the PEEK group were within the allowable range of clinical error. The suitability and trueness of the PEEK RPD framework fabricated by CAD-CAM technology met the requirements of the clinical prosthesis.

A digital workflow for designing and manufacturing metal frameworks and removable partial dentures: A novel dental technique.

The purpose of this technical report is to demonstrate a fully digital workflow for designing and fabricating metal frameworks and removable partial dentures. After obtaining a digital cast of the dental arch with bilateral distal extension defect, computer-aided design software and 3D printing technology are used for the design and fabrication of the removable partial denture frameworks, denture teeth, and denture bases, instead of the traditional workflow. The assembly of the three components is facilitated through a meticulously structured framework. The technology, which prints metal frameworks, denture bases, and denture teeth through different processes with different materials, achieves full 3D printing technology for making removable partial dentures.

Fit Accuracy of Cobalt–Chromium and Polyether Ether Ketone Prosthetic Frameworks Produced Using Digital Techniques: In Vitro Pilot Study

This pilot study aimed to compare the fit accuracy of cobalt–chromium (Co-Cr) and polyether ether ketone (PEEK) removable partial denture frameworks, produced by digital technologies. Two study models of previously prepared Kennedy’s Class I and Class III mandibular dental arches were scanned. For each model, two frameworks were digitally designed and manufactured using a Co-Cr alloy via the selective laser melting (SLM) technique, and using PEEK via the milling technique. A qualitative assessment of the framework’s fit accuracy to the corresponding study models was carried out using calibrated endodontic instruments and image amplification. Best-fit superimpositions between the reference design and the scanned frameworks were performed using the Geomagic Control X version 2018, 3D Systems software, allowing the expression of trueness by calculating the root mean square (RMS) value. Higher fit accuracy was observed for the milled frameworks, with the Class I PEEK framework showing the best fit accuracy to the corresponding model. RMS values were Class I—148.3 μm for Co-Cr and 69.2 μm for PEEK; Class III—107.2 μm for Co-Cr and 59.7 μm for PEEK. In the experimental conditions used, the milled PEEK frameworks showed better fit accuracy and higher trueness than the SLM-printed Co-Cr ones in both Kennedy classes.

A Preliminary Study on the Accuracy of Cast Metal Removable Partial Denture Frameworks Produced from Wax, Printed, and Milled Patterns

To compare the accuracy of two digital workflows for producing resin patterns to be cast into metal frameworks compared to an identical framework manufactured conventionally from a wax pattern. Nine casts were duplicated from a maxillary master cast of a partially edentulous arch. Their accuracy was determined by measuring the same points in two and three dimensions using a reflex microscope, which was also used to measure all frameworks to an accuracy of 4 μm. The same design was used throughout. Three casts were used to make a framework conventionally from an invested wax pattern. Six casts were scanned, and a digital pattern created. Three patterns were milled from a resin block, and three were 3D printed with resin. Then each pattern was cast. The sample size precluded direct statistical conclusions, but no significant differences were found. Duplicate models showed minimal differences compared to the master cast. All patterns and all frameworks showed some level of difference compared to the master cast, but no differences were greater than those reported in the literature as being clinically acceptable. The maximum overall discrepancy between the cast frameworks was 0.64 mm, and at the rest seats was 0.262 mm. Within the limitations of this study, given the very small actual differences both within and between the groups of the three different workflows, the use of digitally produced resin patterns prior to their being cast as metal frameworks is both feasible and well within the accepted limits for clinical acceptability.

The Dimensional Changes of Clasp Arm in Removable Partial Denture Frameworks Fabricated Through DMLS and Conventional Lost Wax Technique: An In Vitro Study

AIM: The aim of the present study is to evaluate the effect of CAD designing on the dimensions of the clasp arm. METHODOLOGY: A Kennedy Class III mod I cast was selected as the reference cast. Samples were divided into 2 groups, Group I with DMLS and Group II with Conventional lost wax technique. Three reference points were selected on the clasp arm and the vertical dimensions were measured in the digital design and compared it with the dimensions at the same points in the final framework. RESULTS: There was slight expansion in group 1 (p-value &gt; 0.05) with mean of -0.035 and standard deviation 0.088. And there was decrease in dimensions in the clasp arm in group 2 (p-value &lt; 0.05) with mean of 0.1741 and standard deviation 0.081. CONCLUSION: From the present study, it was concluded that the dimensions of the clasp arm of DMLS framework increased slightly, whereas the there was significant decrease in the clasp arm dimensions in the framework produced through conventional lost wax technique. Both the frameworks had clinically acceptable fit.

Comparative analysis of the retention force and deformation of PEEK and PEKK removable partial denture clasps with different thicknesses and undercut depths

Statement of problemThe retentive force and deformation of milled polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) removable partial denture (RPD) frameworks are not well understood. PurposeThe purpose of this in vitro study was to assess the retentive force and deformation of PEEK and PEKK Akers clasps with different designs and undercut depths. Material and methodsA master model containing the first and second molar abutments was used to design Akers clasps of different cross-sectional dimensions, undercut depths (0.5 and 0.75 mm), and materials. The components of the removable partial denture framework also included an occlusal rest and were manufactured using a milling machine (n=5). The fatigue resistance of the Akers clasps was measured before and after deformation regarding the retentive forces. ResultsThe PEEK2-U50 clasp had the largest retentive force with no significant difference among all groups before and after the insertion and removal cycle. In addition, the increased cross-sectional dimensions of the design resulted in significant differences in retentive forces between the PEEK1 and PEEK2 groups and between the PEEK and PEKK materials. ConclusionsIncreasing the clasp's cross-sectional dimensions significantly impacted retentive forces, especially between different PEEK groups and between PEEK and PEKK materials.

Patient-reported outcomes and framework fit accuracy of removable partial dentures fabricated using digital techniques: A systematic review and meta-analysis.

This review aimed to summarize the evidence on patient-reported outcomes and clinical performance of digitally fabricated removable partial dentures (RPDs) compared to traditionally fabricated dentures. Three databases were systematically searched (PubMed, CENTRAL, and Wiley online library) for clinical studies comparing digitally and conventionally fabricated RPDs regardless of data acquisition methods used for fabrication. The Cochrane Collaboration risk of bias assessment tool 2 and the Oxford Center for Evidence-based Medicine tool were used to assess risk of bias, and level of evidence, respectively. Descriptive narrative analysis was used to summarize data on patient-reported outcomes, as there were inadequate studies to pool data in a meta-analysis. A random-effects model was used to analyze the data of framework fit accuracy. Ten randomized controlled trials were included in the systematic review, and 4 were included in the meta-analysis. Two studies showed that digitally fabricated RPDs are associated with higher patient satisfaction than conventionally fabricated RPDs (with a mean difference of 12.5mm on a 100-satisfaction scale, p = .008). The pooled standardized mean difference for framework fit accuracy was 0.49 (p = 0.02) in favor of conventionally fabricated RPDs, which showed that conventionally fabricated RPDs have a quantitatively better fit compared to digitally fabricated RPDs. However, clinical evaluation studies showed that both frameworks have clinically acceptable fit. Current evidence shows that digitally fabricated RPDs are associated with higher patient satisfaction compared to conventionally fabricated RPDs. However, the scarcity of literature here warrants the generalization of this conclusion. Both digitally and conventionally fabricated metal RPD frameworks showed acceptable fit clinically.

Which metal surface treatment improves the bond strength between metal alloys and acrylic resin in removable partial dentures? A systematic review.

The union of the metal removable partial denture framework to the heat polymerized acrylic resin is related to prosthesis longevity. However, methods to enhance this bond are not clear to clinicians and dental laboratory technicians. The purpose of this systematic review was to identify which metal surface treatments best increase the bond strength between heat polymerized acrylic resin and removable partial denture alloys. This review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered in the International Prospective Registry of Systematic Reviews (PROSPERO) database (CRD42022384926). Electronic searches were carried out independently, by 3 examiners in Medline/PubMed, Scopus, and Web of Science databases, and in the nonpeer-reviewed literature via ProQuest. The electronic searches resulted in 4143 articles, with 4055 after removing duplicates. After reading the titles and abstracts, 37 articles were selected for reading in full-text version, from which 6 articles were included. All studies evaluated materials for conventional acrylic resin denture base (heat polymerized), processed by water bath, bonded to metal. For the metal framework alloys, cobalt chromium (Co-Cr) alloys were used in 2 studies, titanium (Ti) in 2 studies, and Co-Cr and Ti in the other 2 studies. Different metal surface treatments were used as airborne-particle abrasion with aluminum oxide (particle sizes of 50µm, 110µm, and 250µm) followed by the primer application and the isolated use of the primer, compared to the absence of isolated intervention or airborne-particle abrasion of the metal surface. Among the different primers used, those based on 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) showed the highest acrylic resin-to-metal bond strength values. Airborne-particle abrading the metal with Al2O3 followed by applying a 10-MDP-based primer, increased the bond strength between metal framework alloys and heat polymerized acrylic resin denture base material.

An Experimental Method to Add New Prosthetic Teeth in the Removable Partial Denture Framework: TIG Cold Welding and Preformed Pins

The need to modify removable partial dentures equipped with a metal framework in order to add other prosthetic teeth to replace natural teeth lost by the patient could lead to laboratory procedures so complex as to require the creation of new prostheses with a heavy economic burden. The creation of preformed metal pins to be welded using the economical TIG cold welding method could represent a valid alternative solution with the aim of modifying the prostheses using a reinforced resin capable of adequately resisting masticatory loads. This study evaluates and compares the mechanical robustness and the clinical reliability of these modified prostheses in cases of junctions of one or two contiguous prosthetic teeth. The 6-month follow-up demonstrated the total validity of the method via the absence of significant breakages or detachments in all of the patients analyzed; on the other hand, the prostheses modified using the traditional method and used as controls showed a high incidence of fractures.

Clinical Protocol for Implant-Assisted Partial Removable Dental Prostheses in Kennedy Class I: A Case Report

Patients with Kennedy Class I are usually treated with clasp-retained removable partial dentures (RPDs) as the prosthetic gold standard. For additional stabilization of the RPD, clinicians are often confronted with the question of secondary implant placement, which requires the fabrication of new prostheses. This case report is part of an ongoing multi-center randomized controlled study (RCT) investigating conventional RPDs without and with supplementary implants. A design of the RPD framework, including matrix housings, is crucial to enable subsequent implant retention or support. Ultra-short implants (Straumann TL 4.1 × 4 mm) offer the opportunity for additional support and retention in the edentulous posterior region, where bone availability is often reduced. This future-oriented and minimally invasive approach with virtual treatment planning and guided implant surgery offers the possibility of simplified functional and cost-effective aftercare.

Effect of different digital technology on the adaptation and retention of Co-Cr partial denture frameworks.

To evaluate the overall adaptation and retention of class I cobalt-chromium (Co-Cr) removable partial denture (RPD) frameworks using three different computer-aided design and computer-aided manufacturing (CAD-CAM) technologies: Indirect wax milling with lost wax technique (LWT), direct milling, and selective laser melting (SLM) technique. An educational maxillary stone model (Kennedy class I) was scanned after preparing rest seats to create a resin model. The resin model was scanned, and the RPD framework was digitally designed and saved as a standard tessellation language (STL) file. Twenty-four Co-Cr RPD frameworks were then constructed and divided into three groups (n = 8) based on fabrication technique: Group A (indirect wax milling with LWT), Group B (direct milling), and Group C (selective laser melting). In Group A, the STL file was used to mill the design from castable resin blanks which were then cast by the LWT. In Group B, the STL file was used to mill the design from the Co-Cr blank directly. Finally in Group C, the STL file was used to print the design from Co-Cr powder using SLM 3D printed technique. Geomagic Control X software was used to measure the overall adaptation of the fabricated RPD frameworks, Retention was also tested using a universal testing machine. One-way Analysis of Variance (ANOVA) test was used to compare the three groups then the Tukey HSD post-hoc test was used for pair-wise comparisons. The significance level was set at p ≤ 0.05. Regarding the overall adaptation, Group B (0.71±0.02mm) showed significantly higher adaptation than Group A (0.96±0.06mm) and Group C (1.05±0.16mm). Regarding retention, Group B (2.03±0.34 N) showed significantly higher retention than Group A (1.00±0.13 N) and Group C (0.78 ±0.17 N). Based on the findings of this in vitro study, Co-Cr RPD frameworks fabricated by direct milling technique revealed the best adaptation and retention.

Intaglio Surface Adaptation of Removable Partial Denture Framework Fabricated by Various Data Acquisition Techniques and Fabrication Approaches.

The aim of this study was to compare intaglio surface adaptation of the removable partial denture framework among various data acquisition techniques and fabrication approaches using three-dimensional comparison by metrology software. The partial edentulous typodont model with five digital superimposition landmarks was duplicated and scanned for the digital reference model. Three approaches were the conventional lost-wax (group I; LWT, n = 5), intraoral digital impressions combined with PolyJet printing and lost-wax (group II; IP-LWT, n = 5), and extraoral digital impressions combined with PolyJet printing and lost-wax (group III; EP-LWT, n = 5). Each framework was scanned and superimposed with the reference model. The misfits at 53 locations were measured. Data were statistically analyzed by one-way analysis of variance, followed by Tukey's honestly significant difference for pairwise comparisons (p < 0.05). Significant differences were found between three approaches at the reciprocal arm, terminal part of the retentive arm, rest, and major connector (p < 0.05). In the LWT group, the reciprocal arm and palatal vault region of major connector had the lowest misfits, but the highest misfit was found in the midline region (p < 0.001). In the IP-LWT group revealed the most excessive contact at the terminal part of the retentive arm (-0.111 ± 0.038 mm, p = 0.031), with the highest misfit at the rest area (p < 0.001). A difference in adaptation was found in several removable partial denture framework components among three approaches. The LWT group had a better adaptation than other groups. Nevertheless, a clinically acceptable adaptation was seen in all three approaches.

Wear, Fatigue and Fracture Resistance of Different Monolithic CAD/CAM Onlays As Abutments for Acetal Resin or Cobalt-Chromium Removable Partial Denture Frameworks.

To assess wear, fatigue, and fracture resistance of different CAD/CAM onlays, milled from monolithic Zirconia (Zr), hybrid ceramic (EN), and lithium disilicate (LS), when used as abutments for removable partial denture frameworks fabricated from acetal resin (AR) or cobalt-chromium (Co-Cr). Standard onlays and RPD framework were designed and milled using CAD/CAM. Onlays were cemented with resin cement to identical teeth models. The RPD's occlusal rest surface and the ceramic onlays' rest seats were both 3D scanned before and after 750,000 mechanical load cycles (50 N) and 8,000 thermal cycles (5-55°C) in a chewing simulator. The volumetric loss was measured using 3D image processing software, and the failure of the samples was detected using a stereomicroscope. The fracture resistance was tested by loading to failure in a universal testing machine. The fatigue failure results were analyzed with Fisher's exact probability test and the wear and fracture resistance data were analyzed using two-way ANOVA and Bonferroni Post-hoc test (P<0.05). A significant difference (p<0.05) was found between the tested experimental groups in wear, fatigue, and fracture resistance. Zr/Co-Cr combinations exhibited the least wear and the highest fatigue and fracture resistance (P<0.05), while the highest wear and least fatigue and fracture resistance were recorded for EN/AR group (p<0.05). Zr onlays demonstrated a conservative treatment option with superior mechanical behavior when used as an onlay abutment, regardless of the RPD framework material used. The AR framework is not recommended in the posterior region for removable partial dentures.

Evaluation on a teaching software for removable partial denture framework design.

Removable partial dentures (RPDs) are widely used as a dental prosthesis and have a wide application scope. To explore the effect of using design software in the preclinical teaching of removable partial dentures (RPDs). Unreal Engine software was used to build the RPD framework design teaching and training software. All 131 undergraduate students majoring in stomatology in the class of 2018, Kunming Medical University, were randomly divided into three groups and received either traditional experiment teaching, flipped classroom teaching, or software teaching for RPD design. The application effect of the software in the preclinical teaching of RPD design was evaluated by analyzing the examination results and through the use of a questionnaire survey. The differences in the theoretical examination scores among the traditional teaching group, the flipped classroom group, and the software teaching group were not statistically significant (P> 0.05), while the average design scores of upper Kennedy Class I and lower Kennedy Class II subclass II in the software teaching group were significantly higher than those in the traditional teaching group (P< 0.05). Overall, 75% of the students in the software teaching group reported that this teaching method could improve their learning initiative, a higher percentage than in the traditional teaching group (55.8%, P< 0.05). Meanwhile, 90.9% of the students in the software teaching group reported that the software could make RPD-related theoretical knowledge more visual and intuitive, and 93.2% of these students felt it was helpful for understanding the RPD three-dimensional (3D) spatial structure. These percentages were higher than those in the traditional teaching and flipped classroom groups (P< 0.05). In the preclinical teaching of RPD design, software training helped the students better understand the 3D structure of RPDs and establish clear design ideas, and it may also be valuable for in-depth research and promotion purposes.

Polyetheretherketone (PEEK) as a Biomaterial: An Overview.

Polyetheretherketone (PEEK) is a very powerful biomaterial that is increasingly used in dentistry. It has superior properties, which make it desirable in implantology. The applications of PEEK includefinger prosthesis, RPD and FPD framework, and dental implants. Changes in the production of polyketone-based materials have been made toensure consistent production of polymers for medical applications.PEEK isa high-performance semicrystalline material that has physical properties such as high resilience and strength. It is a tooth-colored material, making it desirable for its aesthetic appearance. Traditional manufacturingmethods like injection molding, extrusion, and compression molding are usedforPEEK. Despite the high price of the polymer, the additional value that PEEK materials bring by offering the possibility of manufacturing parts include lightweight, strength or toughness and able to survive longer in harsh environments.PEEK has trauma or shock cancelling abilities, fracture resisting abilities, stress distributing ability, osseointegrating abilities, With such great qualities PEEK has an increased demand in the market, and this biomaterial never failes to surprise with its amazing success rate.Even in dentistry PEEK has a wide range of applicationswhich includes, as a dental implants biomaterial, prosthetic material, abutment material, post and core material, crowns, removable partial denture framework. With such a huge range of applications PEEK is said to have been providing an all in one package for dentistry.PEEK biomaterial shows great compatibility with bioactive materials which has proven to be of great help to mankind as not only it is involved in life sciences but also in automotives and aerodynamics as well. The main motto of this review is to know the qualities and the properties of PEEK as a capable implant prosthesis for its application focusing on dental implants.This review tells us about the challenges faced when using this material and benefits and advantages ofthis biomaterial.