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Biomedical subjects

R L Schneider

Publications and source records attributed to R L Schneider.

At least 19 recordsLinked to original sources
PubMed1996

Fabricating low-fusing metal casts for more accurate implant prosthodontics.

An important factor that affects the clinical success of dental implants is the way stresses are transferred to the bone via the implant framework and fixture. An ill-fitting implant framework will contribute to these stresses and may result in catastrophic failure of the prosthesis or one of the components and/or fixtures, in addition to possible alveolar bone loss. Many factors may contribute to the difficulty of achieving a passive fit on a complete-arch implant framework. A technique for producing an accurate master cast by using a low-fusing metal is described. The low-fusing metal is dimensionally more accurate than conventional gypsum products. The technique does not require a significant change from conventional chairside and laboratory procedures for complete-arch master cast impressions, and should result in a more passively fitting framework.

Bismuth↗
PubMed1994

A one-appointment procedure for cast post and core restorations.

An accelerated method of using a light-cured acrylic resin and rapid burnout for casting a direct-pattern post and core restoration is presented. Light-cured acrylic resins are an alternative to chemically cured acrylic resins or indirect patterns formed from an elastomeric impression. The procedure can eliminate an appointment for the patient in the fabrication of the post and core restoration and can be completed in most dental offices with minimal laboratory facilities. Chair-side time is saved because of the elimination of one provisional restoration when two are usually required. Laboratory time is also saved because of the decrease in investment setting and burnout time.

Acrylic Resins↗
PubMed1993

Scanning electron microscope analysis of tooth enamel treated with rotary instruments and abrasives.

This study compared the effects of various rotary instruments and polishing agents on tooth enamel. Topographical features of enamel were studied at consecutive stages of polishing with photoanalysis of scanning electron micrographs. The results indicate that enamel modified by diamond burs may be polished to produce the smoothest surface with white finishing stones, Ceramist finishing points, and flour of pumice.

Dental Enamel↗
PubMed1993

Analysis of casualties referred to Army physical medicine services during the Persian Gulf conflict.

This study describes the casualties referred during the Persian Gulf War and underscores the valuable role of Army physical medicine and rehabilitation (PMR) services in evaluation and early rehabilitation of wartime casualties. Data regarding demographics, injury types, medical complications, complications of immobility and functional limitations were collected by military physiatrists at five Army Medical Centers with PMR services. Active duty soldiers injured in the Persian Gulf War who were referred totalled 222. Musculoskeletal injuries occurred in 57%, peripheral nerve injuries in 44%, penetrating wounds in 32%, fractures in 28%, brain injuries in 8%, amputations in 7%, burns in 6% and spinal cord injuries in 3%. The primary referral service was orthopedics (64%). Electrodiagnosis evaluations were performed for 41% of all referrals. Lower limb and upper limb contractures occurred in 10% and 9% of patients, respectively. Ambulatory impairments were seen in 48%. Nerve injuries were associated with penetrating wounds in 68%, with amputations in 67% and with fractures in 58%.

Adult↗
PubMed1993

Improving the outcome of severe head injury with the oxygen radical scavenger polyethylene glycol-conjugated superoxide dismutase: a phase II trial.

Formation of the oxygen radical superoxide anion is one of the final events of several metabolic pathways in the cascade that leads to delayed neuronal death after traumatic or ischemic brain injury. In the laboratory, scavenging of the superoxide anion with native superoxide dismutase (SOD) or polyethylene glycol (PEG)-conjugated SOD (PEG-SOD) has been shown to be beneficial in several types of traumatic and ischemic injury. Accordingly, PEG-SOD was utilized in a randomized controlled Phase II trial to evaluate its safety and efficacy in severely head-injured patients with a Glasgow Coma Scale score of 8 or less. At two institutions, 104 patients were randomly assigned to receive either placebo or PEG-SOD (2000, 5000, or 10,000 U/kg) intravenously as a bolus, an average of 4 hours after injury. Prognostic factors were evenly distributed in the four groups, except for mean age which was significantly higher in the group receiving 10,000 U/kg than in the placebo group (mean age 34 years vs. 25 years). No complications attributed to the study medication were noted. The average intracranial pressure (ICP) was similar in the four groups, but the percentage of time during which ICP was above 20 mm Hg was less in the groups receiving 5000 or 10,000 U/kg of PEG-SOD. Patients in the group receiving 10,000 U/kg also required less mannitol for ICP control than the placebo group. Outcome was assessed using the Glasgow Outcome Scale at 3 and 6 months postinjury in 91 and 93 patients, respectively, by blinded observers not involved in the clinical management of the patients. At 3 months, 44% of patients in the placebo group were vegetative or had died, while only 20% of patients in the group receiving 10,000 U/kg of PEG-SOD were in these outcome categories (p < 0.03, multiple logistic regression test); at 6 months, these figures were 36% and 21%, respectively (p = 0.04). Differences in outcome between the placebo group and either of the other two dosage groups were not statistically significant. It is concluded that PEG-SOD was generally well tolerated and appears promising in improving outcome after severe head injury. A larger, multicenter, Phase III trial, using a higher dose (20,000 U/kg) compared to placebo and to 10,000 U/kg of PEG-SOD is planned.

Adult↗
PubMed1992

The physiological effects of radiotherapy on oral tissue.

An increasing number of head and neck cancer patients are undergoing radiotherapy along or in conjunction with other treatment modalities. Radiotherapy extending over a period of weeks produces a variety of clinical manifestations. This article discusses the physiological changes that occur due to radiotherapy to elucidate the changes seen clinically.

Cranial Irradiation↗
PubMed1989

Bond strengths of intraoral porcelain repair materials.

This study investigated the in vitro shear strength of three porcelain repair systems. Glazed and roughened porcelain surfaces were evaluated. The repair systems tested were Fusion, Scotchprime, and Ultra-Bond. Porcelain cylinders were made. Half of the cylinders were wet-sanded to a flat, nonglazed surface and the remaining cylinders retained a smooth, glazed surface. Specimens were subjected to a shear force parallel to the composite/porcelain interface by use of an Instron Testing machine. Statistical analysis (at the 0.05 confidence level) showed significant differences in mean bond strengths related to the porcelain repair systems and the surface texture.

Dental Bonding↗