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Biomedical subjects

R B Gunderson

Publications and source records attributed to R B Gunderson.

11 recordsLinked to original sources
PubMed2001

The normal development of tibial torsion.

OBJECTIVE: Pathological rotation of the leg is a well-known problem in paediatric orthopaedics. In this study the normal development of tibial torsion during growth was evaluated by computed tomography (CT). DESIGN: Seventy-eight normal individuals (52 children, 26 adults) aged 3-51 years were examined with CT. In axial scans the angle between a line tangential to the posterior part of the femoral condyles and the intermalleolar line, a line through the centre of the lateral and medial malleolus, was measured. The radiation exposure was evaluated and accepted by The National Department for Radiation and the Regional Committee for Ethics in Science. RESULTS: CT showed that the average lateral torsion of the leg at the age of 4 years was 28 degrees with an individual variation of 20 degrees-37 degrees. Later the increase in tibial torsion was on average 1 degrees/year until 10 years of age and, thereafter, 4 degrees until maturity when the mean lateral torsion was 38 degrees (18 degrees-47 degrees). CONCLUSION: Tibial torsion in children mainly develops during the first 4 years of life. After this the increase was of less clinical significance.

Adolescent↗
PubMed2001

A new device to improve cast articulation procedures.

Achieving accurate cast articulation is a challenge for dentists and dental technicians. To ensure accuracy, a convenient, efficient, and predictable technique is needed to stabilize dental casts together, even when the casts are wet. The purpose of this article is to describe the use of a device specifically designed to secure casts together during the articulation process.

Adhesives↗
PubMed1993

New guidelines for preparation taper.

The purpose of this article is to provide new guidelines for minimally acceptable preparation taper by developing a theoretical mathematical foundation based on principles of resistance form. Yes and no are the possible answers to the question, "Does a preparation have resistance form?" This dual nature is useful because in graphing resistance form as a function of taper, potential tapers on the x axis are divided into two groups with an exact dividing point. Tapers less than this dividing point provide resistance form; tapers larger or equal do not provide resistance form. This dividing point makes a reasonable standard for minimally acceptable taper. Average tapers are defined as the limiting average taper and are mathematically determined to equal 1/2 arcsin (H/B), where H is the height of the preparation and B is the base. From this equation, the taper required to provide resistance form for an individual preparation can be calculated by using the preparation's height to base ratio. The equation can also be used to provide guidelines by tooth group. Dies of a prosthodontist were saved and sorted by group (incisors, canines, premolars, and molars). Measurements of 30 dies from each of these groups were used to calculate the average (H/B) ratios and standard deviations. Calculating the limiting average taper by using the average height-to-base ratio minus two standard deviations provides the dividing point taper that is acceptable for over 97% of the preparations. The values calculated are: 29 degrees for incisors, 33 degrees for canines, 10 degrees for premolars, and 8.4 degrees for molars.(ABSTRACT TRUNCATED AT 250 WORDS)

Bicuspid↗
PubMed1991

[Mammographic findings after breast-preserving procedure].

Clinical evaluation of the breast after breast-conserving surgery and postoperative irradiation for carcinoma is made difficult by the changes induced by the treatment. Therefore mammographic evaluation, comprises an important part of the follow-up of these patients. The interpretation of the mammograms requires knowledge of the changes expected to occur after treatment. In this paper we describe such changes as experienced in our department.

Adult↗
PubMed1989

Linear distortion and compatibility of an antimicrobial irreversible hydrocolloid impression material and improved dental stones.

Blueprint Asept Type I irreversible hydrocolloid impression material is claimed by the manufacturers to contain an internal disinfecting agent that is effective within 10 minutes from contact with pathogens. This study examined the accuracy of the material compared with a conventional impression material and its compatibility with two type III and one type IV dental stones. This study did not evaluate the effectiveness of the disinfecting agent.

Alginates↗
PubMedDate not supplied

Modified resin-bonded design for stabilization of mobile teeth: technique and clinical observations.

A design modification of the tooth preparation and framework design is presented to further enhance stabilization of mobile teeth with resin-bonded splints. An appropriate shade of composite resin is placed to restore an esthetic contour, cover the incisal edge framework extensions, and provide occlusal function as indicated. Patient reviews are presented to demonstrate the principles of treatment, versatility, and limitations of this treatment modality.

Adult↗
PubMedDate not supplied

Sequencing platinum foil matrix removal in postceramic soldering of the collarless veneered retainer.

Postceramic soldering of collarless veneered retainers in which the porcelain margins were formed with a platinum foil matrix technique was investigated. The purpose of the study was to determine if removing the platinum foil matrix before or after indexing and soldering procedures would affect the porcelain margin integrity in fixed partial dentures. Prostheses were fabricated on a nickel-chromium laboratory model using both sequences. Six test cycles were performed. Each cycle included one soldering with matrix support and one without the matrix, for a total of 12 solderings. The fixed partial dentures were compared for degree of marginal seating with a measuring microscope and for configuration changes at the porcelain margins with scanning electron micrographs. In the microscopic analysis of marginal closure, soldering without foil matrix was statistically equal to soldering with foil in place. Removal of the platinum foil matrices prior to indexing provided for no further seating of the metal ceramic retainers. Evaluation by scanning electron microscopy demonstrated distinct configuration changes in the porcelain margins for the specimens soldered without matrix support.

Analysis of Variance↗