Did you mean: dental clasps
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BioMed Research International 2021The present study was aimed at reviewing the studies that used finite element analysis (FEA) to estimate the biomechanical stress arising in removable partial dentures... (Review)
Review
The present study was aimed at reviewing the studies that used finite element analysis (FEA) to estimate the biomechanical stress arising in removable partial dentures (RPDs) and how to optimize it. A literature survey was conducted for the English full-text articles, which used only FEA to estimate the stress developed in RPDs from Jan 2000 to May 2021. In RPDs, the retaining and supporting structures are subjected to dynamic loads during insertion and removal of the prosthesis as well as during function. The majority of stresses in free-end saddle (FES) RPDs are concentrated in the shoulder of the clasp, the horizontal curvature of the gingival approaching clasp, and the part of the major connector next to terminal abutments. Clasps fabricated from flexible materials were beneficial to eliminate the stress in the abutment, while rigid materials were preferred for major connectors to eliminate the displacement of the prosthesis. In implant-assisted RPD, the implant receive the majority of the load, thereby reducing the stress on the abutment and reducing the displacement of the prosthesis. The amount of stress in the implant decreases with zero or minimal angulation, using long and wide implants, and when the implants are placed in the first molar area.
Topics: Algorithms; Biomechanical Phenomena; Dental Abutments; Dental Implants; Denture Design; Denture, Partial, Removable; Finite Element Analysis; Humans; Stress, Mechanical
PubMed: 34485518
DOI: 10.1155/2021/5699962 -
Journal of Prosthodontic Research Jan 2022This study comprehensively reviewed the current status of the digital workflow of removable partial dentures (RPDs) and summarized information about the fabrication...
PURPOSE
This study comprehensively reviewed the current status of the digital workflow of removable partial dentures (RPDs) and summarized information about the fabrication methods and material properties of the dental framework, artificial teeth, and denture base.
STUDY SELECTION
We performed a systematic review of the literature published in online databases from January 1980 to April 2020 regarding RPD fabrication and materials used in the related digital technology. We selected eligible articles, retrieved information regarding digital RPDs, and conducted qualitative/quantitative analyses. In this paper, the computer-aided design/computer-aided manufacturing (CAD/CAM) framework, artificial teeth, and denture base materials are reported.
RESULTS
A variety of materials, such as cobalt-chromium alloy, titanium, zirconia, and polyether ether ketone, are used for dental CAD/CAM frameworks. The mechanical strength of the metal materials used for the CAD/CAM framework was superior to that of the cast framework. However, the fitness and surface roughness of the framework and clasp fabricated using a selective laser melting (SLM) method were not superior to those obtained via cast fabrication. Most material properties and the surface roughness of poly methyl methacrylate (PMMA) discs used for digital RPDs were superior to those of heat-cured PMMA.
CONCLUSION
The use of a CAD/CAM framework and PMMA disc for digital RPDs offers numerous advantages over conventional RPDs. However, technical challenges regarding the accuracy and durability of adhesion between the framework and denture base remain to be solved. In digital fabrication, human technical factors influence the quality of the framework.
Topics: Computer-Aided Design; Denture Bases; Denture, Partial, Removable; Humans; Tooth, Artificial; Workflow
PubMed: 33504722
DOI: 10.2186/jpr.JPR_D_20_00117 -
Clinical and Experimental Dental... Feb 2022The purpose of this systematic review and meta-analysis was to compare implant-supported removable partial dentures (ISRPDs) with distal extension removable partial... (Meta-Analysis)
Meta-Analysis Review
Implant-supported removable partial dentures compared to conventional dentures: A systematic review and meta-analysis of quality of life, patient satisfaction, and biomechanical complications.
OBJECTIVES
The purpose of this systematic review and meta-analysis was to compare implant-supported removable partial dentures (ISRPDs) with distal extension removable partial dentures (DERPDs) in terms of patient-reported outcome measures (PROMs: patients' quality of life and satisfaction) and to determine mechanical and biological complications associated with ISRPDs.
MATERIAL AND METHODS
An electronic search was performed on four databases to identify studies treating Kennedy class I or II edentulous patients and which compared ISRPDs with DERPDs in terms of PROMS and studies, which evaluated mechanical and biological complications associated ISRPDs. Two authors independently extracted data on quality of life, patient satisfaction, and biomechanical complications from these studies. The risk of bias was assessed for each study, and for PROMs, the authors performed a meta-analysis by using a random-effects model.
RESULTS
Thirteen articles were included based on the selection criteria. The difference in mean scores for quality of life (30.5 ± 1.8; 95% confidence interval [CI], 24.9-36.1) and patient satisfaction (-20.8 ± 0.2; 95% CI, -23.7 to -17.8) between treatments with conventional and implant-supported removable dentures was statistically significant (p < .05). Implant-supported removable dentures improved patients' overall quality of life and satisfaction. Some mechanical and biological complications, such as clasp adjustment, abutment or implant loosening, marginal bone resorption, and peri-implant mucositis, were noted in ISRPDs during patient follow-up. Studies assessing PROMs were very heterogeneous (I = 65%, p = .85; I = 75%, p = .88).
CONCLUSIONS
ISRPDs significantly improved quality of life and patient satisfaction. Some mechanical and biological complications have been associated with ISRPDs treatment, requiring regular monitoring of patients to avoid the occurrence of these complications.
Topics: Dental Implants; Dental Prosthesis, Implant-Supported; Denture, Partial, Removable; Humans; Patient Satisfaction; Quality of Life
PubMed: 35014207
DOI: 10.1002/cre2.521 -
Journal of Prosthodontic Research Jan 2022This study comprehensively reviewed the current status of digital workflows in fabricating removable partial dentures (RPDs) using evidence from clinical trials and case...
PURPOSE
This study comprehensively reviewed the current status of digital workflows in fabricating removable partial dentures (RPDs) using evidence from clinical trials and case reports.
STUDY SELECTION
We performed a systematic review of the literature on the materials and fabrication of RPDs using digital technologies published in online databases from 1980 to 2020. We selected eligible articles from the search results, retrieved information on digital RPDs from these, and conducted a qualitative analysis. We report evidence from clinical papers and case reports, digital impression-taking methods, and maxillomandibular relationship (MMR) records.
RESULTS
A case report electronically published in 2019 introduced a clasp-retained RPD fabricated via a full-digital workflow without a gypsum definitive cast. Computer-aided design and computer-aided manufacturing of double-crown-retained RPDs with nonmetal materials were described in some case reports. Intraoral scanners were used to obtain digital impressions and MMR records in the fabrication of digital RPDs, which have potential advantages for reducing the number of clinical appointments and simplifying laboratory procedures. Evidence from clinical trials is scarce; a randomized controlled trial reported higher patient satisfaction with digital clasp-retained RPDs than with conventional RPDs.
CONCLUSIONS
Full-digital RPDs can be fabricated without a gypsum definitive cast. However, the indication for full-digital RPDs is limited to cases with Kennedy Class III/IV partially edentulous arches with several missing teeth. Challenges in digital impression-taking and MMR recording remain to be solved to extend these indications. More evidence from clinical trials is required to evaluate the efficacy and usefulness of digital RPDs.
Topics: Computer-Aided Design; Denture, Partial, Removable; Humans; Mouth, Edentulous; Randomized Controlled Trials as Topic
PubMed: 33504721
DOI: 10.2186/jpr.JPR_D_20_00116 -
Journal of Indian Prosthodontic Society 2020The aim was to discuss the indications, contraindications, advantages, and disadvantages of Nonmetal clasp dentures (NMCDs), as well as the most relevant properties of... (Review)
Review
The aim was to discuss the indications, contraindications, advantages, and disadvantages of Nonmetal clasp dentures (NMCDs), as well as the most relevant properties of its constituent materials. A search was conducted using the keywords: "nonmetal clasp dentures," "thermoplastic resin," "flexible resin removable partial denture," "polyamide," and "nylon" in databases PubMed/Medline, Lilacs, SciELO, and textbooks between 1955 and 2020. Theses and texts without reliable sources of publication were excluded. Once the analysis instruments were determined, the data were analyzed and discussed. NMCDs present high flexibility, easy adaptation to the abutments, color compatibility and biocompatibility with the oral mucosa, and absence of visible metal clasps. However, they need laboratory relining, grinding, and polishing, do not have criteria for its planning, become rougher and stained over time, and are able to traumatize supporting tissues. The association with metal components seems to be an alternative to increase the success of NMCDs by combining esthetics and biomechanical principles of conventional removable partial dentures. The lack of long-term clinical studies makes the professionals to rely solely on previous experiences or on the manufacturers' recommendations. It suggested that NMCDs must be indicated with caution when not used temporarily.
PubMed: 33223697
DOI: 10.4103/jips.jips_459_19 -
Dental Materials Journal May 2022Since cast titanium prostheses have many drawbacks, multi-directionally forged titanium grade 2 (MDF) was developed, and the application of the milling process was...
Since cast titanium prostheses have many drawbacks, multi-directionally forged titanium grade 2 (MDF) was developed, and the application of the milling process was proposed for improving the titanium clasp. This in vitro study evaluated milled titanium clasps, including MDF titanium. Milling clasps were manufactured with commercially pure (CP) titanium grade 2 (CP 2), grade 4 (CP 4), Ti-6-Al-4V, and MDF. As a control, a CP 2 cast titanium clasp was fabricated in the conventional manner. No porosities and catastrophic failures were observed in the four milled titanium clasps. Fitness accuracy and retentive forces of milled CP 2 and CP 4 tended to be worse, and the milled MDF showed the higher retentive forces (12.45 N) than did cast and milled CP 2 clasps (9.32 N and 4.42 N). Milled titanium clasps can be recommended for longer-term clinical use as compared to cast clasps.
Topics: Chromium Alloys; Dental Clasps; Denture Retention; Denture, Partial, Removable; Porosity; Titanium
PubMed: 35135942
DOI: 10.4012/dmj.2021-285 -
Polymers Oct 2022The high-performance thermoplastic polyetheretherketone (PEEK) has excellent mechanical properties, biocompatibility, chemical stability, and radiolucency. The present... (Review)
Review
The high-performance thermoplastic polyetheretherketone (PEEK) has excellent mechanical properties, biocompatibility, chemical stability, and radiolucency. The present article comprehensively reviews various applications of PEEK in removable dental prostheses, including in removable partial dentures (RPDs) (frameworks and clasps), double-crown RPDs, and obturators. The clinical performance of PEEK in removable dental prostheses is shown to be satisfactory and promising based on the short-term clinical evidence and technical complications are scarce. Moreover, the accuracy of RPDs is a vital factor for their long-term success rate. PEEK in removable dental prostheses is fabricated using the conventional lost-wax technique and CAD/CAM milling, which produces a good fit. Furthermore, fused deposition modeling is considered to be one of the most practical additive techniques. PEEK in removable prostheses produced by this technique exhibits good results in terms of the framework fit. However, in light of the paucity of evidence regarding other additive techniques, these manufacturers cannot yet be endorsed. Surface roughness, bacterial retention, color stability, and wear resistance should also be considered when attempting to increase the survival rates of PEEK removable prostheses. In addition, pastes represent an effective method for PEEK polishing to obtain a reduced surface roughness, which facilitates lower bacterial retention. As compared to other composite materials, PEEK is less likely to become discolored or deteriorate due to wear abrasion.
PubMed: 36365609
DOI: 10.3390/polym14214615 -
European Journal of Dentistry 2017The purpose of this study was to investigate the importance of pullout location and clasp types in two different environments to dislodge the clasp.
OBJECTIVE
The purpose of this study was to investigate the importance of pullout location and clasp types in two different environments to dislodge the clasp.
MATERIALS AND METHODS
Mandibular test models with natural premolars and molar teeth were used to test four types of clasp (each 12) (Akers, Rest plate Akers, Half and Half, and Ring clasp) with three different pullout location for each type (ring on the rest, loop on the saddle, and wax arising from both rests) in dry and natural fresh saliva environment. Each clasp was pulled out 10 times with a crosshead speed of 10 mm/min, and the force required to withdraw each was measured.
STATISTICAL ANALYSIS USED
A one-way ANOVA and Tukey test were used.
RESULTS
The ring on the saddle pullout location has the highest retention force while ring on the rest was the lowest. In addition, ring clasp has the highest retention force.
CONCLUSION
Clasp type and pullout location had a significant effect on the retentive force.
PubMed: 28729796
DOI: 10.4103/ejd.ejd_70_17 -
Polymers Aug 2022Salivary pH is a neglected factor that may affect the performance of removable dental prostheses (RDP). This study aimed to review literature in reference to the role of... (Review)
Review
Salivary pH is a neglected factor that may affect the performance of removable dental prostheses (RDP). This study aimed to review literature in reference to the role of salivary pH on the performance of RDP and materials used for their fabrication. From January 1990 until December 2021, a search was done on PubMed, Scopus, and Web of Science databases using removable dental prostheses, salivary pH, PMMA, Denture base, and physical properties as keywords. Articles that met the inclusion criteria (full-length articles have investigated the effect of salivary pH on RDP materials in vitro and in vivo) were included. Out of 433 articles, 8 articles that met the inclusion criteria were included. All studies used artificial saliva with different salivary pH ranging between 3 and 14. Two articles investigated the role of salivary pH on the cytotoxicity of denture base resins and soft liner. One article studied the durability and retention of attachments, one article analyzed the performance of PEEK materials, one article researched the fatigue resistance of a denture base, one article investigated the corrosion of RPD framework cast and milled Co-Cr, one article studied the strength and clasp retention and deformation of acetal and PEEK materials, and one evaluated changes in mass and surface morphology of CAD-CAM fiber-reinforced composites for the prosthetic framework. Different salivary pH affected all included materials in this review except PEEK materials. The most adverse effect was reported with alkaline and acidic; however, the acidic showed the most deterioration effect. Salivary pH has a role in the selection of material used for RDP fabrication.
PubMed: 36015644
DOI: 10.3390/polym14163387 -
Medicine Nov 2021The incidence of accidental ingestion and aspiration of foreign body (FB) is likely to occur. Many FBs are discharged spontaneously, but many dental FBs are often sharp...
The incidence of accidental ingestion and aspiration of foreign body (FB) is likely to occur. Many FBs are discharged spontaneously, but many dental FBs are often sharp and may remain in the pharynx, esophagus, and stomach, causing serious complications such as hemorrhage, asphyxia, perforation of the digestive tract, mediastinal emphysema, peritonitis, and ileus. We aimed to examine which type of dental foreign bodies can be removed by endoscope.In this study, we enrolled 32 patients who were evaluated at the Emergency and Critical Center between January 2014 and December 2019 and who accidentally ingested or aspirated dental FBs. Medical records were reviewed to determine the patients' sex, age, medical history, time from accidental ingestion of a FB to consultation, cause, location, occurrence status, nature of the FB, location of retained FB, treatment, complications, and outcome.We enrolled 32 patients (14 men, 18 women), with a mean age of 74.5 ± 12.8 years. Accidental ingestion at treatment was common. The most frequent site where the FB was retained was upper gastrointestinal tract (26 cases, 81.3%). In this study, endoscopic removal was indicated for dentures under the size of 43.3 mm, for dental FB (except dentures) more than 13.6 mm. In dentures, between the number of missing teeth, clasp, type, and endoscopic removal was not statistically significant.Dentures under the size of 43.3 mm was likely to be removed by endoscope. Dental FB (except dentures) more than the size of 13.6 mm was likely to be removed by endoscope. There were no indications for endoscopic removal except for size.
Topics: Accidents; Aged; Aged, 80 and over; Cross-Sectional Studies; Dentistry, Operative; Endoscopy; Esophagus; Female; Foreign Bodies; Humans; Japan; Male; Middle Aged; Retrospective Studies; Treatment Outcome
PubMed: 34797284
DOI: 10.1097/MD.0000000000027602