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The conversion partial denture: a clinical report
Abstract
The treatment alternative described maximizes the benefit of remaining teeth while allowing simplified alteration of the prosthesis if abutments are lost during the life span of the removable partial denture (RPD). A conversion partial is an RPD whose tooth-frame assembly components are individually fabricated and then joined with an acrylic resin major connector. The conversion RPD optimizes retention and stabilization of a terminal dentition and can be easily converted to an immediate complete denture.
... 88 Acrylic has also been used in combination with cast clasp assemblies in an attempt to improve the performance and long-term stability of the RPD. 89,90 More recently, improvements in laser-welding technology have allowed predictable unification of metal components (Fig 9). Cecconi et al described a component approach in which individual parts are fabricated and joined on the definitive cast by means of autopolymerized acrylic resin or laser welding (Fig 10). ...
This article discusses key turning points in removable partial denture (RPD) philosophy. Early advancements tended to focus upon improving the technical quality of the prosthesis itself. The beginning of the 20th century brought significant public pressure upon the dental profession due to consequences associated with poor quality fixed prostheses. The result was dramatic improvement and heavy demand for RPDs. Technical and efficiency issues conspired to temper this enthusiasm, eventually resulting in reduced respect for RPDs. By highlighting key writings and technical issues during these periods of change it is hoped the reader will gain a more precise understanding of the current status of RPD philosophy.
This report presents an alternative method for the retention of partial dentures that relies on the engagement of tooth undercuts by a lining material. The lab procedures are also presented. A new maxillary and mandibular acrylic partial dentures were fabricated using elastomeric retention technique for a partially dentate patient. A partially dentate man reported difficulty in retaining his upper removable partial denture (RPD). The maxillary RPD was designed utilizing elastomeric retention technique. During follow-up, it was necessary to replace the retention rings due to wear. The replacement of the retention rings, in this case, was done through a chairside reline technique. Elastomeric retention technique provides exceptionally good retention can be indicated to stabilize, cushion, splint periodontally involved teeth, no enough undercut for clasps, eliminate extractions, single or isolated teeth.
For the partially edentulous patient, an interim denture can provide acceptable short-term function and esthetics by replacing missing teeth and tissues until a definitive restoration can be performed. This article presents two cases that required interim removable partial dentures to maintain function, phonation, and esthetics until clinical conditions allowed for the fabrication of definitive dentures.
A method of construction of cast clasps with rests for transitional and interim removable partial dentures has been described. It offers the advantages of speed and economy in making acrylic resin appliances firmly retained and supported by cast clasps with rests. It has the disadvantage of being a palliative treatment which may encourage some patients to delay definitive treatment. In any event, it is one method by which many patients may be treated when physical, psychologic, or other problems preclude involved procedures.
A 10-year longitudinal study was carried out on 27 patients treated with RPDs. Before the prosthetic treatment all patients were given oral hygiene motivation and instruction as well as periodontal therapy where indicated. The aim was a high level of cooperation. The RPDs, most of which were lower bilateral distal-extension dentures, were carefully planned and designed. During the follow-up period the patients were examined at yearly intervals, at which time remotivation and reinstruction regarding oral hygiene was given, and scalings, operative restorations, and prosthetic and other treatment procedures were performed as required. Patient cooperation was excellent, and no significant deterioration of the periodontal status of the remaining teeth was found. In addition, there was a low increase in the frequency of decayed and filled tooth surfaces during the decade. The dentures showed damage and several changes during the follow-up period, conditions that necessitated various corrective prosthetic procedures.
Technical considerations have been outlined that will help to produce a transitional removable partial denture that may be placed in the mouth with a minimal amount of adjustment.
From a group of 1480 patients, 1036 were treated with metal frame removable partial dentures (RPDs) at least 5 years before this analysis. Of those, 748 patients who wore 886 RPDs were followed up between 5 and 10 years; 288 patients dropped out. The 748 patients in the study groups were wearing 703 conventionally designed metal frame RPDs and 183 RPDs with attachments. When dropout patients and patients who remained in the study were compared, no differences were shown in the variables analyzed, which indicated that the dropouts did not bias the results. Survival rates of the RPDs were calculated by different failure criteria. Taking abutment retreatment as failure criterion, 40% of the conventional RPDs survived 5 years and more than 20% survived 10 years. In RPDs with attachments crowning abutments seemed to retard abutment retreatment. Fracture of the metal frame was found in 10% to 20% of the RPDs after 5 years and in 27% to 44% after 10 years. Extension base RPDs needed more adjustments of the denture base than did tooth-supported base RPDs. Taking replacement or not wearing the RPD as failure criteria, the survival rate was 75% after 5 years and 50% after 10 years (half-life time). The treatment approach in this study was characterized by a simple design of the RPD and regular surveillance of the patient in a recall system.
A technique is described that allows a removable partial denture with a broken clasp or a removable partial denture in which an abutment has been extracted to be restored by the reattachment of a new cast clasp component or a complete surveyed clasp assembly. The technique is applicable to most clasp designs and can include attachment to the acrylic denture base or the metal major connector. The technique is distinguished from other repair techniques by (1) providing a cast clasp replacement, (2) allowing the patient to retain the prosthesis during the repair, (3) generating a precisely formed surveyed clasp assembly by the laboratory, and (4) including an efficient transfer mechanism for the precision clasp created in the laboratory to be attached to the removable partial denture in the dental office. A two-step impression procedure is used to ensure proper relation of the partial denture to the abutments.
Most removable partial denture frameworks constructed today are one-piece castings. This article presents the Component Partial, a removable partial denture in which the framework is constructed in pieces. Such construction ensures a more accurate fit of the RPD.
A new indexing procedure is described for the conversion of removable partial dentures when extraction of additional teeth is planned. Advantages and disadvantages of the indexing procedure are reviewed and compared with traditional treatment options. The new procedure facilitates the use of dental laboratory expertise and facilities and allows the patient to retain the prosthesis throughout the process. A component that includes teeth, denture base segments, and wire or cast clasps is created by the laboratory and attached by the dentist during the extraction visit as a simple denture repair procedure. The procedure can also be used to convert an existing partial denture to an immediate complete denture. Required clinical and laboratory procedures are described.
Restoration of a periodontally compromised dental arch with a removable partial denture may require one or more design modifications. Multiple rests ensure that adequate vertical support remains in the event primary abutment teeth are lost. An open or closed base can be strategically placed in the maxillary major connector to facilitate the replacement of subsequently lost teeth. The location of finish lines can be modified to provide a smoother resin-to-metal transition when posterior teeth are lost. Wire direct retainers that provide more physiologically acceptable clasping of compromised teeth and that are easily adjusted and added to the prosthesis should be considered.
McCracken's Removable Partial Prosthodontics
- Gp Mcgivney
- Ab Carr
McGivney GP, Carr AB. McCracken's Removable Partial Prosthodontics.
10th ed. St. Louis: Elsevier Science; 1999. p. 255.
McCracken's Removable Partial Prosthodontics
- G P Mcgivney
- A B Carr
McGivney GP, Carr AB. McCracken's Removable Partial Prosthodontics.
10th ed. St. Louis: Elsevier Science; 1999. p. 255.