Cast Metal Framework Research Articles

Classification system for maxillary fixed dental prostheses.

To present an addendum to existing fixed dental prostheses (FDPs) classification system for maxillary prostheses. The new classification identifies the relationships between FP-1 (fixed prostheses) designs and newly developed clinical interdental gingival contours. Clinical and laboratory descriptions of the various types of full-arch fixed prostheses are described with photographic illustrations. Benefits and limitations of the various prosthetic designs are explained. Surgical differences in the amount of alveolectomy are illustrated. One clinical case is demonstrated. A new classification system for maxillary implant fixed complete dentures is presented. The new system will serve as an improved communication aid for clinicians, patients, and laboratory technicians. Treatment of patients with edentulous maxillae and/or terminal dentitions and implant fixed complete dentures include several options relative to design and materials. Restorative space can have a major impact on prosthesis design and longevity. Early on in dental implant therapy, prostheses were generally made with cast metal frameworks, denture bases and denture teeth. Prosthetic complications were widely reported. With increased clinical experience and improved materials, computer-aided design and computer-aided manufacturing (CAD-CAM) protocols were developed that allowed stronger prostheses to be constructed in reduced or small restorative volumes. FP-1 ceramic implant-supported fixed prostheses (CISFPs) are designed to replace only the dental hard tissues and to promote preservation and rehabilitation of gingival soft tissues. The physical properties and minimum thickness requirements in full arch prostheses are influenced by several factors including distances between implants and rigid connector sizes. FP-1 CISFPs may be the closest prostheses the profession can offer edentulous patients that mimic the look, feel, and function of missing dentitions. Aesthetic outcomes of FP-1 CISFPs are variable and depend on a multitude of factors. This article presented a classification system that builds on existing classification by identifying the level of papilla heights achieved with FP-1 CISFPs.

Rehabilitation of post mucormycosis surgical defect using definitive obturator with cast metal framework- A case report

The recent outbreak of covid-19 disease has led to development of mucormycosis in immunocompromised individuals. Treatment options include antifungal drugs, surgical removal of infected tissues, and management of underlying metabolic disorders. Surgery typically includes the complete excision of the diseased region. These defects put the patient at risk for nasal twang, fluid leaks into the nasal cavity, and poor masticatory function. In such defects, the obturator prosthesis can create an oro-nasal seal. This case report describes the rehabilitation of post mucormycosis surgical defect using definitive obturator using cast metal framework.

The impact of an additional implant under the saddle of removable partial dentures in Kennedy Class II edentulism on oral health-related quality of life and oral function: a case series report

BackgroundImplant-supported removable partial dentures (ISRPDs) provide effective prosthodontic treatment for partially edentulous patients. ISRPDs offer greater patient satisfaction and better oral function compared with removable partial dentures (RPDs) by enhancing denture stability and support. However, few clinical studies have focused on RPD design in patients with mandibular Kennedy Class II edentulism. The aim of this case reports was to investigate the oral function, oral health-related quality of life, and satisfaction of four patients with unilateral distal-extension mandibular RPDs with the same design which were replaced with ISRPDs. In addition, we investigated how each patient’s evaluation varied with the change from RPD to ISRPD.Case presentationFour patients had unilateral distal-extension mandibular edentulism and were missing the first and second molars and the first and second premolars. They received one implant (4.0 mm in diameter, 8.0 mm in length; IAT EXA PLUS Bone level; Nippon Piston Ring Co. Ltd, Saitama, Japan) at the position equivalent to the first molar in the edentulous residual ridge perpendicular to the occlusal plane. Implant position was determined by surgical guide plate. RPDs were fabricated after the residual mucosal membrane had healed. The basic design of the RPD was as follows: a cobalt–chromium alloy cast metal framework denture with a lingual bar as the major connector, a double Akers clasp on the molars and an auxiliary retainer on the premolar as indirect retainers, and a wrought wire clasp and a cast cingulum rest (combination clasp) as direct retainers. Masticatory performance, occlusal force, oral health-related quality of life, and satisfaction were estimated at baseline, and at time points after insertion of the RPD and after insertion of the adapted ISRPD. Each evaluation item showed a tendency for improvement on insertion of the new RPD. Masticatory performance and satisfaction tended to be better after insertion of the ISRPD than after insertion of the RPD.ConclusionOur findings suggest that ISRPDs provided better patient satisfaction and masticatory performance than RPDs in patients with mandibular Kennedy Class II edentulism.Trial registration UMIN Clinical Trials Registry and Japan Registry of Clinical Trials, UMIN000025283 and jRCTs012180003. Registered 19 February 2016 and 17 December 2018, https://www.umin.ac.jp/ and https://jrct.niph.go.jp/

CAD-CAM denture teeth made on cast metal removable partial denture frameworks

Once the fit of the cast metal framework on a removable partial denture (RPD) has been verified, the manufacturer’s prefabricated denture teeth are typically secured on the cast metal framework to prepare for a wax evaluation. Although prefabricated denture teeth are available in different tooth forms and sizes, they require modification to fit an edentulous space. In arches with severe space discrepancy, it may be inefficient and time-consuming to make modifications to prefabricated denture teeth. The technique described uses digital technology to fabricate custom denture teeth on a cast metal framework and establish harmonious occlusion. An edentulous space with more than a single tooth replacement is designed as a splinted fixed partial denture with a connector. The designed teeth are milled in the double-cross-linked polymer to prepare for a wax evaluation, and once verified, the RPD is processed by using heat polymerization. Modifications are made to the milled denture teeth after wax elimination to reduce the likelihood of acrylic resin bond failure.

A simplified technique for fabrication of obturator using light curing wax pattern: A case report

Surgical excision of the maxilla results in communication between the oral cavity, nasal cavity and maxillary sinus. Rehabilitation of such defects involves fabrication of obturator prosthesis by the maxillofacial prosthodontist. Various techniques and materials have been used in the past for rehabilitation of such defects.To Fabricate a Obturator Prosthesis using Light Cure Wax Pattern.A 65-year-old man reported with the chief complaint of inability to chew food due to an ill-fitting prosthesis. His history revealed that patient had undergone maxillectomy of left side due to Carcinoma maxilla 03 years back, followed by the fabrication of a definitive obturator prosthesis. Intraoral examination revealed a well healed Aramany’s Class II post maxillectomy defect on the left side measuring 5 cm X 3.5 cm anteroposteriorly and mediolaterally, with everted margins and irregular borders. This clinical report describes rehabilitation of maxillectomy defect with definitive obturator prosthesis. A light cure wax pattern was used (LiWa®; Willmann & Pein Gmbh) for the fabrication of metal framework.Fabrication of a cast metal framework involves a complex laboratory procedure to achieve the clinical success of the prosthesis. LiWa light curing waxes can be successfully used as an alternative to the conventional wax pattern for the fabrication of cast partial dentures framework for definitive obturators.The light cure wax pattern helped in reducing the number of laboratory steps and allowed wax pattern trial in the patient's mouth, saving precious time and ensuring a precise fit of the prosthesis.

Framework Materials for Full-Arch Implant-Supported Rehabilitations: A Systematic Review of Clinical Studies.

The purpose of this systematic review was to investigate the clinical outcomes of frameworks made of different materials in patients with implant-supported full-arch prostheses. A literature search was conducted on MEDLINE, Scopus and Cochrane Library, until the 1st of March 2021, with the following search terms: framework or substructure combined with “dental implants”. The outcomes evaluated were: implant and prosthesis survival, bone resorption, biological and technical complications. The Cochrane Handbook for Systematic Reviews of Interventions was employed to assess the risk of bias in randomized clinical trials. The Newcastle–Ottawa quality assessment scale was used for non-randomized studies. In total, 924 records were evaluated for title and abstract, and 11 studies were included in the review: 4 clinical randomized trials and 7 cohort studies. The framework materials investigated were: gold alloy, titanium, silver-palladium alloy, zirconia and polymers including acrylic resin and carbon-fiber-reinforced composites. High implant and prosthetic cumulative survival rates were recorded by all included studies. Various materials and different fabrication techniques are now available as alternatives to traditional cast metal frameworks, for full-arch implant-supported rehabilitations. Further long-term studies are needed to validate the use of these materials and clarify their specific clinical indications and manufacturing protocols to optimize their clinical outcomes.

Laboratory assessment of the accuracy of two different resins designed for 3D printing for cast metal frameworks and suprastructures

Laboratory assessment of the accuracy of two different resins designed for 3D printing for cast metal frameworks and suprastructures

A Comparative Gap Analysis Study using Stereomicroscopy between Screw Retained Zirconia Frameworks, TILOP Selective Laser Sintering Frameworks and Conventional Cast Metal Frameworks

Background: The target of this in vitro study was to compare and analyze the gap between abutment finish lines and implant analogues using stereomicroscope between three different screw retained frameworks; Zirconia Frameworks, TILOP45 Selective Laser Sintering Frameworks and Conventional Cast Metal Frameworks Materials and Methods: This In-vitro study involved the construction of a total of eight models. Three screw-retained frameworks were constructed on each model hence creating three groups; Group A, B and C. For Group A: Screw-retained frameworks were constructed using the conventional cast metal technology as For Group B: Screw-retained zirconium frameworks were constructed using the CAD/CAM technology and finally For Group C: Screw-retained frameworks were constructed using the Selective Laser sintering SLS technology TILOP 45 (TILOP = Titanium Low Oxygen Powder). Final frameworks of each group were screwed over each model and then using stereomicroscope, a gap analysis was performed.Results: When comparing the mean gap values of the three groups, the study has shown that there was a statistically significant difference in the mean gap values between both the Zirconia and TILOP45 frameworks and the conventional cast frameworks (p<0.001). The highest mean gap Value was found in conventional cast frameworks while the least mean gap value was found in the Zirconia frameworks. Results also revealed that there was no statistically significant difference in the mean gap values between the Zirconia Frameworks and the TILOP45 Selective Laser Sintering Frameworks.Conclusion: Within the limitations of this study, it can be concluded that selective laser sintering technology as well as the CAD/CAM Zirconia technology renders more passive frameworks than the conventional cast method. There seems to be a very close similarity between the accuracy of frameworks constructed with the selective laser sintering technology and the CAD/CAM Zirconia technology.

No clear evidence on the clinical performance of different removable prosthetic options in partially edentulous patients.

Data sourcesMedline/PubMed, Embase, BIOSIS/Ovid, SciSearch/DIMDI, Cochrane library, FIZ Technik Web and hand searches of the journals; Clinical Oral Investigations, International Journal of Prosthodontics, Journal of Prosthetic Dentistry, Deutsche Zahnärztliche Zeitschrift, Swiss Dental Journal, Journal of Dentistry and the Journal of Dental Research.Study selectionRandomised controlled trials, prospective and retrospective studies on survival rates of removable dental prostheses in the moderately reduced dentition with at least 15 participants having an observation period of at least two years, and a dropout rate of less than 25% were considered.Data extraction and synthesisTwo reviewers abstracted data. A qualitative summary of the included studies was carried out. Studies providing data that permitted a Kaplan-Meier analysis were included in meta-analysis.ResultsThe review included 19 studies, six of which were in multiple publications. Cast-metal framework dentures showed failure rates of 33% and 50% after five years. One study with a 25-year observation period reported failure rates of 50%. Proper pretreatment and a good recall scheme improve the results. Bilateral attachment prostheses showed failure rates of 11% and 30% after five years. Unilateral attachment prostheses showed failure rates of 75% after five years. Double-crown prostheses dentures show failure rates of 0% to 21.7% after three to six years.ConclusionsWithin the limitations of this study, it seems that removable partial dentures, (RPD), given suitable pretreatment and follow-up regimes, can provide a satisfactory treatment option. Based on only one paper, they revealed acceptable results even over a very long observation period (25 years).

A Combination Prosthesis Using Thimble Copings for Reconstruction of Mutilated Dentition: A Case Report at Nobel Medical College, Biratnagar

Planning and executing the restorative rehabilitation of a severely mutilated dentition is one of the most challenging tasks for the restorative dentist. This case report illustrates an interdisciplinary approach in the treatment of a multifaceted case of partial loss of teeth. A series of provisional prosthesis were used before the final treatment due to extreme complexity of the patient situation. The final treatment was composed of innovatively designed thimble copings, telescopic retainer and cast metal frame work for the rehabilitation of the maxillary and mandibular arch.Birat Journal of Health Sciences Vol.2/No.1/Issue 2/ Jan - April 2017, page: 222-226

Reinforcement of provisional restoration with cast metal framework: A case report

Reinforcement of provisional restoration with cast metal framework: A case report

Early Loaded Single Implant Reinforced Mandibular Overdenture.

Rehabilitating atrophied mandible with two-implant supported denture is a common treatment modality for implant retained removable overdenture in mandible. This paper aims to design a treatment modality where single implant reinforced overdenture is fabricated for a severely atrophied mandibular ridge with early loading protocol. Results of studies have shown that a single implant mandibular overdenture significantly increases the satisfaction and quality of life of patients with edentulism. Midline fracture of the prosthesis is the most common complication related to single implant and two-implant retained mandibular overdentures. To manage such complication, a thin metal mesh is used to reinforce the overdenture and also to make the prostheses lighter and cost effective as compared to conventional cast metal framework.

Effect of Framework in an Implant-Supported Full-Arch Fixed Prosthesis: 3D Finite Element Analysis.

The aim of this study was to analyze through a three-dimensional finite element analysis (3D-FEA) stress distribution on four implants supporting a full-arch implant-supported fixed prosthesis (FFP) using different prosthesis designs. A 3D edentulous maxillary model was created and four implants were virtually placed into the maxilla and splinted, simulating an FFP without framework, with a cast metal framework, and with a carbon fiber framework. An occlusal load of 150 N was applied, stresses were transmitted into peri-implant bone, and prosthodontic components were recorded. 3D-FEA revealed higher stresses on the implants (up to +55.16%), on peri-implant bone (up to +56.93%), and in the prosthesis (up to +70.71%) when the full-acrylic prosthesis was simulated. The prosthesis with a carbon fiber framework showed an intermediate behavior between that of the other two configurations. This study suggests that the presence of a rigid framework in full-arch fixed prostheses provides a better load distribution that decreases the maximum values of stress at the levels of implants, prosthesis, and maxillary bone.

Digital impressions for fabrication of definitive "all-on-four" restorations.

The aim of this study was to assess the accuracy of digital impressions for "all-on-four" implant rehabilitation. Patients edentulous in one or both jaws were randomly selected for this study. Complete arch immediately loaded prostheses supported by 4 implants (2 axial and 2 tilted) were placed. Five hours after implant placement, screw-retained full-arch temporary prostheses were positioned. After 4 months, a digital scan body was used to finalize definitive prosthesis. Radiographic assessments were obtained immediately after surgery and at each follow-up visit. Bone level measurements were reported at 6 and 12 months, and bone loss between upright and tilted implants was compared. Fourteen definitive cast metal frameworks prosthesis were delivered to the patients. No implant dropout occurred. All prosthesis were screwed onto the dental implants, and x-ray examinations revealed a bar-implant connection accuracy. The implant survival rate was 100% for all positioned implants. No statistically significant differences (P > 0.05) in crestal bone loss between tilted and upright implants were detected. Digital impression creates an accurate physical model significantly improving efficiencies for the dental team and streamlining the workflow.

Prosthetic rehabilitation of a traumatic mandibular defect using alveolar distraction and an implant-supported hybrid prosthesis: A clinical report

Prosthetic rehabilitation of edentulous sites with concomitant alveolar deficiency is always an esthetic and functional challenge. In the current case, the advantages of distraction osteogenesis and hybrid prosthesis with a cast metal framework were used to restore esthetics and function. The surgical elegance of distraction osteogenesis combined with the variety of features of hybrid prosthesis ensured successful rehabilitation, patient comfort and ease of maintenance. This case report highlights the need for meticulous preoperative planning and selection of the right options, both surgical and prosthetic to effectively restore complex oral defects using implants. Traumatic defects are mostly accompanied by hard and soft tissue loss. This report describes the surgical and prosthetic treatment of a patient with a traumatic mandibular defect. The trauma resulted in the loss of numerous mandibular teeth and extensive loss of bone particularly in the anterior mandible. In order to restore the lost hard and soft tissues, the treatment plan comprised of alveolar distraction osteogenesis in the anterior mandible followed by an implant supported screw-retained FP-3 prosthesis. This article also describes a technique to ensure a passive well-fitting cast metal framework for the fixed removable screw-retained hybrid prosthesis. Clinical Relevance to Interdisciplinary Dentistry Placement of implants in compromised edentulous ridges often results in a compromised final prosthetic outcome. This case report describes an interdisciplinary approach to manage hard and soft tissue ridge defects using alveolar distraction osteogenesis, followed by implant placement and prosthetic rehabilitation using a hybrid denture. The integration of the faculties of prosthodontics, oral and maxillofacial surgery, and oral and maxillofacial radiology was the key factor that determined the successful completion of this complex and technically demanding case.

Pregled retencijskih elemenata mobilnih djelomičnih proteza ovisno o vrsti bezubosti i zubima nosačima u komercijalnim laboratorijima u Ateni

The aim of this survey was to record removable partial denture (RPD) retentive elements and abutment teeth in partially edentulous patients, identified in commercial laboratories in Athens, Greece.628 master casts with the corresponding cast metal frameworks used in the construction of RPDs were evaluated. Casts were photographed to identify the number and position of existing teeth, the partial edentulism class and the retentive elements. Prevalence tables and the x(2) test were used for the statistical analysis of the collected data (α=.05).There were 276 maxillary (43.9%) and 352 (56.1%) mandibular casts. Maxillary edentulism entailed almost a total absence of right third molars in 96.7% and left third molars 96.0% of casts, with lower rates for the first and second molars. Edentulism in the posterior mandible presented a similar pattern. The most profound findings concerning retentive elements were: 91.9% of the retainers used were clasps and the remaining 8.1% were attachments. Of the clasps used, 48.9% were of the Roach Τ type, a finding more common in Kennedy Class I as compared to other Kennedy Classes (p<0.01). The circumferential clasps accounted for 19.3% of the total clasps used, and it was less frequently presented (8.8%) in Kennedy I Classes (p<0.01).Roach clasps were used in the majority of cases whereas RPI clasps and attachments were rarely used.

Prosthetic Rehabilitation of Maxillectomy Defect with Cast Metal Framework and an Acrylic Hollow Bulb -A Case Report

Prosthetic Rehabilitation of Maxillectomy Defect with Cast Metal Framework and an Acrylic Hollow Bulb -A Case Report

Stress Analysis of an Overdenture Using the Finite Element Method

The purpose of this study was to examine the influence of reinforcing the structure of an overdenture on stress distribution in the residual ridge using the three dimensional finite element method. Four models of mandibular overdentures with various reinforcement methods were analyzed, including (1) without reinforcement, (2) with chrome-cobalt reinforcing wire, (3) with a reinforcing structure (a cast metal framework) and no reinforcement on the coping top, and (4) with a reinforcing structure and reinforcement on the coping top. The reinforcement adjacent to the top of the coping and the medial part reduces the stress beneath the loading side of dentures and widely and evenly distributes the stress of the residual alveolar ridge.

Oral rehabilitation using customized intra-radicular Dalbo attachments

Teeth may be lost because of trauma, caries, periodontal disease, congenital defects and iatrogenic treatment. Tooth loss has a negative impact on masticatory function, esthetics and self-image. Fixed partial dentures, removable partial dentures, complete dentures and implant-supported dentures can replace missing teeth comfortably and esthetically, but it is not known whether they differ in their ability to reconstruct the masticatory function, phonetics and esthetics and preserve the residual bone ridge. Despite recent developments in dental implantology, the conservative approach to root preservation is still valid. In view of increased root caries rate in the elderly arid lax oral hygiene habits of the most overdenture wearers, placing protective copings on root abutments, when economically feasible, is the preferred method of treatment. Retention of overdentures is increased by including stud attachments in the abutments. Incorporation of cast metal frameworks is recommended to prevent base fractures. Clinical Relevance to Interdisciplinary Dentistry With some patients, the operating dentist alone cannot accomplish the correction, but may require the assistance of other dental disciplines. This case report describes an interdisciplinary approach for the coordinated treatment of a patient with badly broken down and missing teeth. The patient's functional and esthetic expectations were successfully met with interdisciplinary treatments, including Oral prophylaxis followed by treatment for benign migratory glossitis. Endodontic treatment for two grossly carious teeth. Cast partial dentures for the maxilla and mandible.

Maintenance of Implant Hybrid Prostheses: Clinical and Laboratory Procedures

Fixed implant hybrid prostheses have been used for the last 40+ years in the treatment of edentulous patients. These prostheses have provided long-term masticatory function for thousands of patients. The original treatment protocol included fabrication of cast metal frameworks that fit accurately on the restorative platforms or abutments and/or endosseous implants. Frameworks were designed to splint implants together; they also provided retention and support for the functional and esthetic portions of the fixed hybrid prostheses. Initially, edentulous patients were treated with maxillary complete dentures and mandibular fixed, hybrid prostheses. Denture teeth were used in both prostheses. Over the span of many years, occlusal surfaces of the denture teeth in the mandibular prostheses exhibited signs of occlusal abrasion and wear, sometimes completely abrading the teeth and denture bases, resulting in framework exposures. Ultimately, this resulted in decreased chewing efficiency and loss of vertical facial height. Patients would then return to clinicians and ask for retreatment. In certain instances, the underlying frameworks would have to be remade. This involved replicating the original series of appointments and significant additional expense to patients and clinicians alike. The protocol presented in this article avoids having to remake the most expensive portion of fixed implant prostheses--the frameworks. The protocol identifies the clinical and laboratory procedures involved in using existing frameworks and replacing preexisting denture bases and denture teeth, with minimal inconvenience to patients.