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Biomedical subjects

R E McKinstry

Publications and source records attributed to R E McKinstry.

At least 19 recordsLinked to original sources
PubMed1995

Resin dental casts as an aid in bite mark identification.

Two techniques are presented for the fabrication of resin dental casts to aid in bite mark analysis. The first technique produces visible light cured dental casts of the suspected biter's dentition. These casts can be compared to the victim's bite marks or photographs of the bite marks. The technique is rapid and casts of the suspected biter's dentition can be made in less than thirty minutes, which is advantageous when the elimination of possible suspects must be accomplished in a timely fashion. The second technique involves the fabrication of crystal clear epoxy resin dental casts of the suspected biter's dentition. The dental casts are translucent and permit visualization through the teeth when comparisons are made to the bite marks or to tracings or photographs of the bite marks. The casts can also serve as an educational tool for a jury or juries in trials involving bite mark evidence. The resin dental casts are less brittle than dental stone casts permitting storage without concern for breakage for periods of years.

Bites, Human↗
PubMed1992

Silicone nasal radiation carriers.

A technique for fabrication of a flexible shielded afterloaded silicone nasal radiation carrier is described. The technique uses a rubber base impression of the nasal cavity from which a silicone radiation carrier is made. Plastic tubes for afterloading of the radioactive sources and a lead shield were incorporated into the carrier. The carrier permitted accurate location of the radioactive sources in the nasal cavity and reduced the radiation exposure.

Brachytherapy↗
PubMed1992

Microwave-cured tracheostoma vents.

This article describes a technique of making custom flexible and combined flexible/rigid tracheostoma vents. The combined flexible rigid tracheostoma vent provides a flexible material that is nonirritating in the peristomial region and maintains a patent tracheostoma by the rigidity of the hard acrylic resin section. The flexible tracheostoma vent can be easily inserted and is more comfortable than the rigid commercially available tracheostomy tube. The use of microwave-cured materials permits fabrication during a single visit. The steps involved in the fabrication of the tracheostoma vents are simple and require no elaborate laboratory equipment.

Acrylic Resins↗
PubMed1992

A homemade microwaveable denture reline jig.

This article describes a procedure for making a denture reline jig for processing denture base resin in a microwave oven. The jig is intended for use with the newer microwave curing denture base resins. The reline jig is economical to produce and is made from fiberglass liquid resin commonly used in automobile body repairs. The fiberglass liquid resin is strengthened by adding fillers of dental stone and chopped fiberglass strands.

Calcium Sulfate↗
PubMed1992

Microwave processing of cleft palate orthopedic expansion devices.

This article describes a method for making a palatal expansion device for use in conjunction with orthopedic repositioning of the premaxilla in patients with bilateral cleft palate. The technique of constructing the devices involves the microwave processing of a permanent soft liner and a heat-cured acrylic resin in a single-stage curing cycle. The resultant expansion device has the advantages of a soft liner for retention in the nasal cavity and an oral cavity surface that is smooth and closely adapted to the tissues. A paper cover is used during the flasking process, which allows packing of materials without displacement into undesirable locations.

Acrylic Resins↗
PubMed1991

The use of visible light-cured resin system in maxillofacial prosthetics and neuro-orthopedic surgery.

The use of visible light-cured (VLC) resin was evaluated in contrast to more traditional chemical-cured resins for reconstruction of the spine in experimental rats. Such procedures are used to reconstruct vertebra in humans following corpectomy for neoplastic destruction of the spine. Numerous disadvantages exist in the use of chemical-cured resins, including excessive heat generated during the polymerization, cytotoxic effects of the nonpolymerized monomers on adjacent tissues, increased risk of infection due to impaired immunity, and distortion problems with the polymers. A new visible light-cured resin, Triad, was tested for use in maxillofacial prosthetics and for vertebral body replacement in neuro-orthopedic surgery. This study evaluated the biocompatibility of the VLC resin system as a bone implant material. The results of this study have shown the VLC resins underwent polymerization without substantial exothermic reaction and the biologic testing indicated that they are nontoxic and biocompatible. Some of the advantages noticed by using VLC resin are accuracy of fit and ease of fabrication and manipulation.

Acrylic Resins↗
PubMed1991

Microwave processing of permanent soft denture liners.

This article describes a technique of processing a resilient soft denture liner using microwave irradiation. The technique employs a specially designed flask that can be heated in a microwave oven. The flask can be either fabricated using commonly available dental laboratory materials or purchased commercially. The microwave polymerization of the resilient soft denture liner reduces the potential warpage of the denture base that can occur during the conventional process of boiling in water for 2 hours. Additionally, microwave irradiation reduces processing time to less than 1 hour, allowing the dentist the opportunity to reline a patient's denture in a single visit. The technique is simple and requires no extensive or elaborate dental laboratory equipment.

Denture Liners↗
PubMed1990

How to make microwavable denture flasks.

One can make a microwavable denture flask that will accommodate obturators and other large intraoral prostheses. A method for making a dental stone flask pattern and a latex mold makes it possible to produce fiberglass flasks strong enough for compression molding. These flasks are economical to produce and are made from the fiberglass liquid resin that is used in automobile body repairs. The fiberglass liquid resin is strengthened by the addition of dental stone and chopped fiberglass strands. The resultant flasks allow successful microwave polymerization of acrylic resin for denture bases while still being able to follow conventional flasking and packing techniques.

Dental Equipment↗
PubMed1989

The effect of clinical experience on dental students' ability to design removable partial denture frameworks.

To determine whether clinical experience influenced dental students' ability to correctly design removable partial denture frameworks, four combinations of six casts depicting various partially edentulous situations were used in the study. The authors independently rated the casts as to the degree of difficulty on a three-point scale. Only those casts for which there were 100% agreement were used. All of the casts that were used had a moderate degree of difficulty rating (level 2). The dental student sample consisted of 34 second-year students who had just completed 98 hours of instruction in removable partial dentures. Each student was given six casts on which to design removable partial denture frameworks. The students were evaluated before clinical experience in removable prosthodontics and after 1 year of removable prosthodontic experience. The results indicated that the dental students made significantly fewer errors in framework design after clinical experience. Errors on two of 13 framework design items were increased postclinically. The increase in errors on these two items may have been the result of a lack of attention to detail or a lack of reinforcement in learning certain basic concepts.

Clinical Clerkship↗
PubMed1989

Pulp test response of the maxillary anterior teeth in cleft palate patients.

The relative pulpal responsiveness of the six maxillary incisors to electrical and cold thermal stimuli was tested in patients with complete unilateral and bilateral clefts. The six maxillary anterior teeth were tested at random to electrical stimuli. After a 5-minute interval, the same teeth were tested at random to cold stimuli with an ice pencil. Unilateral and bilateral cleft palate patients had statistically significant higher mean electrical pulp test thresholds for the maxillary anterior teeth than the noncleft palate patients. No statistically significant difference between unilateral and bilateral cleft palate patients was found in electric pulp test responses of the maxillary anterior teeth. No statistically differences in electric pulp test responses and cold test responses of the maxillary anterior teeth in both cleft palate and noncleft palate individuals based on differences in sex were observed. No statistically significant difference in cold test responses were observed between cleft palate and noncleft palate patients. Cleft palate patients who completed orthodontic treatment within 1 year of testing showed elevated mean electrical pulp test thresholds as did noncleft palate patients who received orthodontic treatment within 1 year of testing.

Adolescent↗
PubMed1989

Pin and screw retained palatal prostheses in cleft palate patients.

This article reviews the rationale and technical procedures for pin and screw retained palatal prostheses. These prostheses provide a useful treatment modality for cleft palate patients requiring two stage palatal repair, obturation for a large fistula, or single stage repair requiring palatal expansion in the presence of an unerupted primary dentition. Additionally, dental arch alignment can be achieved through the incorporation of an expansion screw device in the prosthesis. Post insertion problems of air and fluid leakage around the prosthesis, inflammation of the tissue underneath the prosthesis and possible damage to unerupted teeth have been observed, but are rare occurrences in properly selected cases.

Bone Screws↗
PubMed1987

Transverse relationships of the infraorbital foramina in cleft and noncleft individuals.

An evaluation of the location of the infraorbital foramina in a transverse plane was undertaken by direct skull and radiographic measurements in unrepaired cleft palate and age- and sex-matched noncleft individuals. Physioprints were obtained on six dry skulls with left-sided clefts of the primary and secondary palates and on six age- and sex-matched noncleft palate skulls. The left infraorbital foramen was found to be significantly superior in a transverse plane to the right infraorbital foramen in the cleft palate skulls. No significant differences in transverse location of the infraorbital foramina were found in the cleft skull group based on differences in sex or age. Posterior-anterior cephalographs were obtained on 15 left unilateral cleft palate individuals and on age- and sex-matched noncleft palate individuals. The location of the infraorbital foramina in a transverse plane in the posterior-anterior cephalographs was found to be too variable to permit the use of parametric statistical tests. When the data on location of the infraorbital foramina were analyzed by a nonparametric statistical test it was found that the left infraorbital foramen was significantly superior to the right infraorbital foramen in the cleft palate individuals. The more superiorly placed infraorbital foramen on the cleft side was suggestive of a vertical deficiency of the maxilla on the cleft side.

Adolescent↗
PubMed1985

Prosthodontic considerations in the management of surgically compromised cleft palate patients.

Prosthodontic habilitation with speech aid prostheses for surgically compromised cleft palate patients has been discussed. It can be concluded that surgical redivision of the soft palate with removal of the levator veli palatini muscles as an aid to construction of a pharyngeal obturator is contraindicated. Surgical redivision with removal of the levator muscles prevents subsequent surgical procedures and commits the patient to a prosthesis for life. The management of nonfunctional pharyngeal flaps, large soft palate perforations, and patients with palatopharyngeal insufficiency and/or incompetency secondary to surgical repairs was also discussed. If the prosthodontist is routinely consulted in the initial treatment planning, alternatives to surgical management might be considered for patients with high potential for postsurgical deficiencies.

Cleft Palate↗
PubMed1985

Speech considerations in prosthodontic rehabilitation of the glossectomy patient.

A knowledge of normal articulation is needed before the prosthodontist can assess the compensatory articulation used by glossectomy patients. The amount and portion of tongue resected is directly correlated with speech intelligibility. The loss of the tip of the tongue is more critical to intelligibility than a hemiglossectomy. Partial glossectomy speakers can often use the residual tongue stump to perform adaptive movements that approximate normal movements and should be treated as an articulation problem. The compensatory articulation used by the total glossectomy patient was reviewed. The prosthodontic management of patients with partial tongue resection often includes lowering the palatal vault, while the management of the total glossectomy patient usually requires a mandibular tongue prosthesis. These prostheses can be refined with the use of multiview videofluoroscopy, videotaping, and spectrographic analysis.

Dentures↗
PubMed1983

Clinical evaluation of the mandibular staple bone plate.

Some of the problems in the use of the mandibular staple bone plate are improper placement of the implant labiolingually, gingival reaction around the pins, and compression loading of the implant. The use of the patient's denture to determine proper angulation and the preparation of the transosteal posts can eliminate improper placement. Mucogingival grafting can be used to treat the inflammatory gingival reaction around the posts, and compression loading can be controlled by proper recognition during processing, placement, and patient education.

Bone Nails↗