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Biomedical subjects

D N Firtell

Publications and source records attributed to D N Firtell.

12 recordsLinked to original sources

Mandibular complete denture impressions with fluid wax or polysulfide rubber: a comparative study.

Some authors have stated that wax cannot be used to make impressions for complete dentures, while others have found that wax has some advantages over elastomeric impression materials. The purpose of this study was to compare mandibular impressions made with a fluid wax to those made with light-body polysulfide rubber. Fifteen maxillary and mandibular complete dentures were made using fluid wax as a final impression material. For comparison, 15 maxillary and mandibular complete dentures were made using light-body polysulfide rubber. The number of adjustments required over 1 year was recorded. No statistical difference in adjustments was noted between the two groups.

Aged

An appliance to correct mandibular deviation in a dentulous patient with a discontinuity defect.

The mandibular discontinuity defect is one of the most difficult problems in prosthetic dentistry. This article describes an appliance that has been used successfully in reducing or correcting the deviation in dentate patients who have experienced mandibular resection. It consists of a prefabricated integrated tube and plunger that are hinged to clear acrylic resin maxillary and mandibular appliances.

Acrylic Resins

Root retention and removable partial denture design.

The position of a retained root for preservation of a ridge requires modification of the design of a distal-extension removable partial denture on the side of the retained root. A model with silicone rubber over the ridges and simulated retained roots was fabricated. A framework with mesial rests, distal proximal plates, and I-bar clasp arms was fitted to it. A pencil lead was attached to the framework to record the arcs of rotation of the I-bar clasp arm. The movements and the fulcrums of the prosthesis were changed by the presence of simulated retained roots posterior to the distal abutment.

Dental Abutments

Current concepts in cranioplasty.

A review of the methods of cranioplasty has been presented. A method of prefabrication of an alloplastic cranial implant has been described as well as a review of 40 patients with whom this technique was used.

Acrylic Resins

Primary malignant melanoma of the mouth.

This report described primary malignant melanoma of the maxilla in the region of the palate and gingiva, the two most common locations of oral melanoma. It fulfilled the three criteria for a primary lesion as described by Greene and others, that is, malignant melanoma was demonstrated in the oral mucosa by biopsy examination, intraepidermal activity was present, and melanoma was not present at any other site. Treatment consisted of partial maxillectomy and the immediate use of maxillofacial prosthetics to offer the patient the maximum comfort in early rehabilitation.

Diagnosis, Differential

A stent for a split-thickness skin graft vestibuloplasty.

Accepting the requirement that there must be intimate contact between a split-thickness skin graft and the underlying periosteum in a vestibuloplasty, a method of forming a stent to meet this.criterion is presented. The procedure uses an overextended impression and a custom-made acrylic resin base. Two methods of modifying the base with a secondary impression to form a stent at the time of the operation are described.

Humans

Complete denture prosthodontics for the radiation patient.

The increased use of radiation therapy for the control of oral cancer necessitates that all dentists concerned with the rehabilitation of oral cancer patients be familiar with this treatment modality. Radiologic equipment, the rationale for their use, and the sequelae to oral treatment are discussed. Misconceptions have developed concerning the advisability of prescribing complete dentures following radiation therapy. However, clinical experience in the Maxillofacial Unit at the University of California, San Francisco, indicates that most radiation patients can wear complete dentures. The need to follow sound prosthodontic techniques is advocated, along with a few modifications related specifically to the radiation patient. Patient cooperation and meticulous care during and following the placement of dentures are stressed to minimize the risk of tissue necrosis and to preserve the well-being of the patient.

Alveolar Process

Light-weight RTV silicone for maxillofacial prostheses.

Weight is a problem in retention of large skin-textured maxillofacial prostheses. The purpose of this investigation was to test the feasibility of mixing foam RTV silicone rubber with conventional RTV silicone rubber to obtain a light-weight material. Various mixtures of foam and conventional silicone rubber were formulated and tested for strength, accuracy of molding, color application, color stability, and texture. A special flask to support the mold was necessary in order to overcome expansion problems associated with gas formation of the foam silicone rubber. The mold required venting to release the gas and to reduce the expansion of the prosthesis in order to maintain accuracy. Molding, accuracy, texture, and color problems were overcome. Reduction of weight proportionate to reduction of tear strength of the material formulated, however, did not allow routine use of mixtures of foam and conventional silicone. When the weight of a prosthesis is critical and excessive and thickness is sufficient to give adequate strength, the foam and conventional silicone mixture can be used.

Color