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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↗
PubMed1984

Cast post and core for nonparallel canals.

A method for fabrication of a cast core with non-parallel tapered posts has been presented. This direct method does not require the use of a graphite post to preserve the channel for the accessory post during casting.

Crowns↗
PubMed1983

Removable partial dentures with rotational paths of insertion: problem analysis.

Removable partial dentures designed to use a rotational path of insertion are technique sensitive. When indicated and when the principles discussed are followed, a denture that uses a rotational path can be highly successful. Tooth coverage can be decreased, which is an advantage in plaque control, caries reduction, and periodontal support. Esthetics can be improved without resorting to intracoronal retainers, and the number of components subject to distortion is reduced. When properly designed and constructed, use of a rotational path of insertion can result in a removable partial denture that is strong, hygienic, and esthetic.

Dental Arch↗
PubMed1983

Porosity in boilable acrylic resin.

An acrylic resin developed to be processed by boiling for 20 minutes in water was compared to a conventional heat-processed acrylic resin for porosity when processed according to the manufacturer's directions. No porosity was found in the conventional resin in thicknesses up to 19.5 mm. The boilable resin developed porosity in thicknesses of 6 mm and greater. The porosity increased with increased thickness. The boilable resins should not be used for long-term prostheses or those requiring a thickness of acrylic resin that approaches 6 mm.

Acrylic Resins↗
PubMed1982

Maxillofacial prosthetics in the dental school curriculum.

A survey was sent to all dental schools in the United States to ascertain what type of training in maxillofacial prosthetics was included as a separate course or included within other courses. Eighty-six percent of the questionnaires were returned. The results indicated that, while only 31% of the respondents offered a specific course in maxillofacial prosthetics, much of this information was offered in several other dental school courses. Specific information should be included in the curriculum on subjects such as radiation therapy and chemotherapy. However, the emphasis should be aimed at familiarizing the dental student with the objective and scope of maxillofacial rehabilitation without providing details regarding the fabrication of the infinite variety of maxillofacial prostheses. This general information is essential so that dental students realize that appropriate treatment of carcinoma patients includes prosthetic rehabilitation and they can counsel and refer their patients appropriately.

Curriculum↗