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Biomedical subjects

D N Firtell

Publications and source records attributed to D N Firtell.

At least 19 recordsLinked to original sources
PubMed1992

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↗
PubMed1992

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↗
PubMed1991

Color stability of provisional materials in vivo.

Color stability of provisional restorations is an important quality of the resin used, particularly for extensive reconstruction over a long period of time. This study evaluated the in vivo discoloration of seven resins over a 9-week period. Resin specimens were prepared and placed in the facial flange of maxillary complete dentures and the lingual flange of mandibular complete dentures. Patients were given toothbrushes and toothpaste and told not to use any chemical agents for cleansing the dentures. Observations were made at 1, 5, and 9 weeks. No change was detected at the first two evaluations. At the 9-week evaluation, four materials, True Kit, Duralay, Trim, and Protemp, showed significantly less staining than did the other three resins tested. All materials tested were acceptable from the standpoint of color stability for short term (5 weeks or less) provisional restorations. Therefore, the dentist using provisional restorations for a short period of time may consider other properties of the materials, such as resistance of fracture, marginal accuracy, ease of fabrication, and cost.

Acrylic Resins↗
PubMed1987

The effect of clinical remount procedures on the comfort and success of complete dentures.

Fifteen patients were treated with complete dentures in a routine manner that included a clinical remount. A second group of 15 was treated in the identical manner except that the clinical remount was not performed. The occlusal patterns of all dentures were recorded in the patient's mouths at delivery and again 1 week later by using a photoelastic membrane to provide a permanent record. The presence or absence of soreness was also noted for each patient during the week after delivery. Results indicate that clinical remounts significantly reduced the incidence of soreness, preserved the occlusal force, and reduced the changes in occlusal patterns of the dentures. Although both cusped and flat teeth were used in both treatment groups, no significant differences were noted in relation to either form on the basis of the indices studied.

Consumer Behavior↗
PubMed1986

Attitudes toward abutment preparation for removable partial dentures.

A questionnaire was sent to 58 dental schools to determine what type of abutment preparation is being used in conjunction with removable partial dentures. Responses from 43 schools indicate that enamel modification and cast restorations are still the primary type of abutment preparations. Amalgam alloys are widely used, and composite and acid-etched retained restorations are also being used.

Attitude of Health Personnel↗
PubMed1985

Reaction of the anterior abutment of a Kennedy Class II removable partial denture to various clasp arm designs: an in vitro study.

Five clasp arm designs were selected for in vitro testing of the anterior abutment of a Kennedy Class II removable partial denture. The clasps were a circumferential clasp with the cast retentive arm placed at the survey line, a circumferential clasp with a cast retentive arm placed into a mesiofacial undercut of 0.01 inch, a circumferential clasp with a wrought wire retentive arm placed into a mesiofacial undercut of 0.01 inch, a buccal I-bar placed at the greatest facial curvature into a 0.01 inch undercut, and a half T-bar buccal arm placed into a 0.01 inch distofacial undercut. The relative movement of the abutments was recorded by a polygraph on a line from a point of force in the extension and through the rest seat of the anterior abutment, 90 degrees from the first direction, and vertically in the long axis of the abutment. The amount of movement of the abutment tested varied relative to the clasp design and the directions recorded. The cast circumferential arm placed at the survey line consistently showed less movement, and a cast circumferential arm placed into an undercut showed the greatest total movement. The decision to use any of these clasp arm designs should be correlated with other clinical conditions that are present for a specific patient.

Dental Abutments↗
PubMed1985

Pressure indicators for removable prosthodontics.

P.I.P. and Coltene pressure spot indicator were tested on the same 30 sets of complete maxillary and mandibular dentures and on two maxillary dentures against natural dentition. They were tested at delivery for pressure spots, but adjustments were not made. They were tested again after 24 hours to visualize and compare actual pressure spots. Half the dentures were adjusted according to P.I.P. and half according to Coltene pressure spot indicator. The patients were recalled after 1 week to determine if they were free from discomfort. The P.I.P. showed a greater clinical correlation of predictable to actual pressure spots and enabled the investigators to spare more patients from post-delivery discomfort.

Dental Stress Analysis↗
PubMed1985

Laboratory accuracy in casting removable partial denture frameworks.

An attempt was made to compare the clinical accuracy of two types of cast metals used in the fabrication of removable partial dentures as they were prepared by commercial laboratories. No comparison of the metals could be made, because the discrepancies that were found were too gross and were related to technical error. Suprabulge clasps were placed in less undercut than prescribed. Infrabulge clasps were placed in more undercut than prescribed. The laboratories produced better accuracy when they were informed of the purpose of the cast frameworks than when the frameworks were made without the knowledge that their work would be tested. One laboratory produced better results than the other under similar conditions.

Chromium Alloys↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1976

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↗
PubMed1976

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↗