Fabricating abutment crowns for existing removable partial dentures using custom resin clasp analogs

A universal approach for fabricating abutment crowns for existing removable partial dentures is described. A replica (analog) of the clasp assembly is generated and transferred to a traditional working cast, which includes the abutment die. The analog is incorporated into the working cast as a removable component to allow the formation of the crown contours. The article reviews in detail the procedures required to transfer accurately all the essential components and information from the mouth to the working cast while allowing the patient uninterrupted use of the removable partial denture. Prestabilizing the removable partial denture, creating the analog impression, avoiding errors due to soft tissue components, forming a precise analog base, selecting materials, generating a rigid resin analog, and prescribing a path of insertion and withdrawal to the analog are described. The method replicates all types of clasps and can generate all types of fixed prosthodontic retainers to function harmoniously with the existing partial denture.     

Comparative clinical evaluation of removable partial dentures made from impressions with different materials

Impressions for removable partial dentures (RPDs) should provide an accurate and detailed record of the teeth and soft tissues. Removable partial denture casts should be exact replicas of the mouth to ensure that RPD frameworks fit accurately and are fully adjusted to oral structures. A comparative clinical evaluation was performed on the oral fit of RPDs made from impressions with either irreversible hydrocolloid (alginate) or condensation silicone. The difference between the two groups was found to be statistically significant.     

Removable partial denture with a lateral rotational path of insertion

A removable partial denture with a lateral path of insertion is useful when unsightly facial clasps are objectional to the patient. Rounded rest seat preparations allow extensions of the minor connector to rotate laterally into embrasure undercuts, providing retention. Guiding planes on the contralateral side ensure a different path of withdrawal from the retentive elements. A Kennedy Class IV arch with a long edentulous span is used to illustrate the denture design.     

Immediate addition to acrylic partial dentures

The conventional method of adding teeth to an existing prosthesis has the disadvantage that patients must be without their dentures while the teeth are added. Whilst a new immediate denture avoids this, it means that the patient will have to grow accustomed to the shape of a new polished surface. The method described in this paper eliminates these problems by making an immediate addition to the existing partial denture. Additionally, the technique has been found to be beneficial to those patients who are unable to tolerate conventional impression taking procedures.     

A secondary lingual casting for removable partial dentures

This article describes a technique for constructing a nickel chromium alloy lingual casting that reinforces a removable partial denture against heavy anterior occlusion. The metal can be cast into a thin secondary casting, and it is easily etched and bonded to the resin anterior teeth and associated base. This type of lingual casting has the potential to provide a simple and effective solution to the problem of repeated fracture or displacement of anterior teeth in many restorations.     

An alternative restorative method for regional odontodysplasia: case report

A 5-year-old Caucasian male presented with early loss of multiple deciduous teeth. All the characteristics were consistent with the diagnosis of regional odontodysplasia (ROD). Significant initial findings included premature loss of multiple primary mandibular teeth and some malformed permanent teeth. The affected teeth showed hypoplastic enamel and dentin, short roots, and wide pulp chambers, and were localized in the mandibular dentition. Treatment objectives for this patient were to provide improved esthetics, restored chewing function, and space maintenance by the construction of a temporary prosthetic restoration. However, with limited tooth support and an unusual occlusal pattern, it is difficult to obtain satisfactory retention and esthetics with traditional prosthetic techniques. In this article we introduce an alternative method for fabricating a custom removable denture and discuss the prognosis of the malformed permanent dentition and further treatment plan.     

The effect of immediate dentures on maxillomandibular relations

Immediate mandibular and maxillary dentures were made for six patients to determine the relative changes in the vertical dimension of occlusion and rest position over a 3-month test period. The dentures were mounted on the articular in centric occlusion (habitual). Pilkington-Turner anatomic teeth were used on the maxillary denture, which was set against a flat, noninterfering acrylic resin occlusion rim instead of mandibular posterior teeth. Positional cephalometric measurements in centric occlusion and rest position were made before extraction and at 1-week, 1-month, 2-month, and 3-month intervals. The dentures were relined after 2 months. The results were as follows: 1. In the centric occlusion position the mandible moved forward after 1 week and remained forward for the 3-month test period. 2. The rest position showed no significant change in the anteroposterior position of the mandible with time. 3. The vertical dimension of occlusion and rest showed a gradual decrease over the entire test period. 4. The reline procedure did not affect the trend of the dimensional changes. 5. A noninterfering occlusal scheme is advantageous for immediate dentures.     

The use of bar attachment in removable dentures

The results of treatment of 230 patients with dentition defects are presented. Plate, arch, and removable bridge dentures were used fixed with a special clammer suggested by the authors. The follow-up has shown good functional and esthetic characteristics of the suggested denture designs.     

The use of attachments for the fixation of removable dentures

A new design of OT-cap system attachment for removable denture fixation is offered improving fixation reliability, functional and esthetic characteristics of dentures. Establishment of attachments when the jaws are maximally tightly compressed helps evenly distribute the masticatory loading of the underlying tissues and abutment teeth individually for each patient.     

Removable partial overdentures

A technique for applying the overdenture concept to removable partial denture construction has been presented. Endodontically treated abutments are prepared with cast gold posts and copings over which removable partial dentures with conventional components are fabricated. No special materials or complicated laboratory techniques are required, and the maintenance and repair problems of precision attachments are avoided. A variety of potential uses and advantages of the technique are discussed.     

Tooth stabilization and splinting before and after periodontal therapy with fixed partial dentures

The design and use of fixed partial dentures as a definitive restoration to stabilize and splint teeth have been reviewed. The provisionalization of the splinted patient has been described as it is incorporated into the treatment plan of patients with a weakened periodontium. The current controversy of incorporating implants in the patient requiring splinting was discussed, and recommendations are made. Dentists are encouraged to explain all potential ramifications of splinting with fixed partial dentures, including cost, frequency of office visits, and potential alterations or remakes of the prosthesis should physiologic demands surpass the capabilities of the remaining teeth.     

Removable partial prostheses for the elderly

Elderly partially edentulous patients can have teeth replaced with removable or fixed prostheses supported by mucosa, teeth, or implants. Age per se does not influence which option is best. Instead, the relative health of the patient, dental tissues, and the patient's finances determine treatment. A three-level index of these factors, the PTF index, is proposed to assist in the decision-making for treatment. Removable partial prostheses (RPPs) can be indicated for all patients because RPPs offer esthetic, versatile, noninvasive, and reversible features. They are particularly indicated when remaining teeth are questionable. If teeth are lost, they can be more easily added to existing RPPs compared with fixed prostheses. Six changes to ideal designs are illustrated in this article for prostheses with a compromised dentition, to make continued prosthetic service simpler.     

Allosteric nicotinic receptors, human pathologies

The purpose of this study was to investigate the biomechanical significance of major connectors and base mucosal contacts on the mechanical behaviour of maxillary removable partial dentures in vivo. Six subjects wearing maxillary dentures retained by conical crowns were selected for the study. Reflective photoelasticity and strain gauges were used to monitor the development of strain/stress during functional loading. Loading tests were performed initially with a denture design including a palatal major connector and denture bases and then repeated after removal of the major connectors and denture base alveolar muccosa contacts. The palatal major connector and the denture bases mucosal contacts contribute significantly to the rigidity and stability of removable partial dentures retained by conical crowns.     

Occupational medicine on the turn of the 21st century--analysis of changes and their determinants

Cross-sectional and longitudinal studies have identified that persons wearing overdentures require regular care and maintenance of their dentures and their remaining dentition. This paper reports on a longitudinal study of the denture treatment needs of 284 dentures placed in 254 patients seen over a period of 12 years. At placement of the overdentures, baseline measurements and photographs were made by a single examiner. These measurements included evaluation of the restorations, abutment height above the gingival margin, periodontal probing depths, and oral hygiene. Denture status was evaluated by examining stability, retention, the integrity of the denture bases, and the relationship of the teeth in centric occlusion. Denture hygiene was also assessed. Based upon this examination, the subjects' denture treatment needs were determined. The majority of overdentures were well tolerated, and in general the patients were satisfied with their dentures. The most common denture treatment need was cleaning, followed by adjustment of the denture bases. Relining was a more common problem in the mandibular arch than in the maxillae. The need for occlusal adjustment did not seem to be a problem after the fifth year, but this might have been because of replacement of worn teeth or dentures. The majority of denture repairs were necessitated before the sixth year. Patients who received immediate dentures did not have greater treatment needs. Looseness of the dentures was the primary complaint, followed by sore teeth and denture-bearing tissues. In spite of their complaints, the great majority of the patients were satisfied with their overdentures.     

Polyvinyl siloxane template aids in recontouring natural teeth opposing single dentures

This article describes a procedure that provides proper reduction of natural teeth opposing complete dentures. By use of a polyvinyl siloxane prosthetic template, natural dentition can be reduced to a more favorable plane, which will facilitate denture construction. This procedure will eliminate the risk of arbitrary grinding and will minimize guesswork through guided intraoral reduction.     

Cephalometric evaluation of the changes in patients wearing complete dentures: a 20-year study

The purpose of this continuing longitudinal investigation was to study the changes on the craniofacial complex in complete denture wearers; herein are reported the 20-year findings. At the onset of the study complete dentures were made for 64 persons. Two dentures techniques were employed: a complex method of construction and a simplified method. At the start of the project the patients' ages ranged from 30 to 60 years (average age 53 years) and all had been edentulous for at least 1 year (range 1 to 30 years). Lateral cephalometric radiographs were made immediately after initial placement of the dentures and during subsequent years (1, 2, 3, 4, 5, 7, 10, 15, and 20). The same cephalostat was used throughout and all films were exposed with the teeth in centric occlusion. Thirty-four subjects presented for the 20-year follow-up. Of this number, the radiographs of 24 subjects (14 women and 10 men; average age 65.5 years [range 50-83 years]) (12 complex denture wearers; 12 simplified technique denture wearers) were used in this report (10 had denture alterations over the 20-year period that excluded them). The 20-year observations corroborate earlier findings. There is a loss of the vertical dimension of occlusion as viewed from the right profile, and the mandible rotates in a counterclockwise fashion resulting in an increase in relative prognathism. The maxillary alveolus was stable, the mandibular alveolus resorbed, and the dentures rotated counterclockwise and shifted slightly forward. The observed changes were not significantly affected by the sex of the patient or by the denture technique employed.     

Application and survival rate of partial fixed dentures with combined retainers (adhesion wing, inlay, onlay, overlay, crown)

Bridges at least with two types of retainers (adhesive frame-work, inlay, onlay, overlay, or crown) might be called fixed partial dentures with combined retainers. The aim of the present study was to compare the fixed partial dentures with combined retainers made at our clinic between 1986 and 1996. In our study the cumulative proportional survival of the combined bridges was found 80%. Examining the loss of the combined bridges it seems that in the first year 1% of the bridges came off. The rest was lost between 12th and 48th months.     

The 1993 General Social Survey I: alcohol use in Canada

Natural dentitions of elderly people are often reduced and the remaining teeth are heavily restored. It is unknown whether they are satisfied or dissatisfied with this situation. To get more insight into this phenomenon 320 dentate non-institutionalized elderly subjects were clinically examined and interviewed by means of a questionnaire. Analysis of the data showed that only 13% of the subjects had at least a complete dentition from the right first molar to the left first molar; 50% had less than four occlusal units, 39% of the subjects were wearing a removable partial denture. Ninety per cent of the subjects was satisfied with the dental state and nearly all subjects mentioned they could chew well (97%), despite the fact that 91% of the subjects mentioned they had to deal with one or more dental discomforts. Satisfaction decreased significantly when the number of the occlusal units was reduced or a removable partial denture was present. The conclusion is drawn that although the dentitions of the elderly are often reduced they are, in general, satisfied with their dental state.     

Mechanical considerations for the implant tooth-supported fixed partial denture

The implant tooth-supported fixed partial denture presents a biomechanical design problem, because the implant is rigidly fixed within the alveolus, and the tooth is surrounded by a periodontal ligament that allows movement. Nonrigid fixed partial denture designs are advocated by some dentists as a method of compensating for this differential movement. Rigid fixed partial denture designs, however, are advocated by many clinicians. Studies have failed to show the advantage of one design over the other. This study developed an in vitro method for testing such prosthesis designs and measured movement of a natural tooth abutment during simulated function. The movement of the natural tooth abutment was not found to change substantially with the fixed partial denture designs tested.     

Surface charges on membranes

The mesial rest-I-bar concept is the most important contribution to clasp partial denture design in the last 30 to 40 years. When used with discernment in situations where it is not contraindicated, it constitutes an excellent design for extension-base removable partial dentures. It has become the design of choice for an increasing number of dentists. Use of the three elements that make up the clasp assembly does not necessarily insure that the clasp will function as intended. There are situations for which it should not be used. Unless adequately adjusted after framework construction as well as during the maintenance program, the beneficial effects may be more imaginary than actual. Strict adherence to the mesial position for the rest is not rational for toothsupported dentures and may be questioned for some extension-base prostheses. I-bars have several advantages as direct retainers. However, no single type of retainer is applicable for all retentive situations, and other types should be selected where conditions are unfavorable for I-bar use. A framework which permits a slight amount of movement toward the edentulous residual ridge is an important consideration in design of extension-base removable partial dentures, particularly for those of the mandibular arch. However, compromise of this principle is sometimes necessary to satisfy other design requirements. Design of the framework is only one of the factors that contribute to a successful removable partial denture. Of at least equal importance is the adequacy of support provided by the denture base and the nature of the occlusion. If meticulous attention is directed to these two factors, the forces transmitted to the teeth through the framework can be kept to a minimum and within physiologic tolerance. Conversely, neglect of these considerations may cause a framework of any design to become destructive.