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Biomedical subjects

D A Curtis

Publications and source records attributed to D A Curtis.

33 records · Page 2Linked to original sources
PubMed1989

A comparison of protrusive interocclusal records to pantographic tracings.

The rationale for recording protrusive mandibular movement is to accurately adjust an articulator. Techniques to record condylar inclination include radiographic interpretation, extraoral tracings, and intraoral recording materials. This study compared the protrusive settings on an articular adjusted by a pantograph to protrusive settings recorded by two intraoral recording materials, one a polyvinyl siloxane material and one a laminated, metalized wax. Pantographs were completed for 20 patients by using a kinematic hinge axis and conventional pantographic techniques. The patients also had three protrusive interocclusal records made with two intraoral registration materials completed and averaged. The average condylar inclination recorded with a pantograph (29.5 degrees) was greater than the recording by either intraoral registration material. Standard deviations ranged from 4.1 degrees to 6.6 degrees. An analysis of variance showed that the condylar inclination recorded by wax was statistically less than recorded with a pantograph. A comparison between the pantograph and the polyvinyl siloxane displayed no statistically significant difference in recording condylar inclination.

Adult↗
PubMed1989

Shear bond strength of visible-light-cured resin relative to heat-cured resin.

One promising clinical application of visible-light-cured (VLC) denture resin is for relining complete and partial dentures. Typically, a VLC resin would be used to reline an existing prosthesis fabricated from heat-cured resin (HCR). This study measured the shear bond strength of a VLC resin bonded to HCR specimens by different bonding agents. For comparison, we measured the shear bond strengths of VLC resin bonded to VLC resin specimens and of autopolymerizing resin (APR) to HCR specimens. Cylindrical specimens of HCR (n = 126) and VLC (n = 24) were thermocycled to simulate aging, and the bonding surfaces were prepared by being sanded to approximate clinical roughness. The specimens were divided into seven groups of approximately 20 each, and test materials were bonded by different bonding agents. Statistical analysis by ANOVA and the Student-Newman-Keuls test showed significant differences (p less than 0.05) among all groups except APR to HCR/no bonding agent, VLC to HCR/VLC bonding agent, or VLC to HCR/VLC and HCR bonding agent. The traditional bond of APR to HCR with HCR bonding agent was significantly stronger (p less than 0.05) than the strongest bond of VLC to HCR with HCR and VLC bonding agents.

Acrylic Resins↗
PubMed1988

Occlusal considerations for partially or completely edentulous skeletal Class II patients. Part II: Treatment concepts.

Four basic concepts must be considered when developing the prosthetic occlusion for skeletal class II patients: (1) Centric relation must be used as a reference position to relate the mandible to the maxillae; (2) the posterior denture teeth must be positioned close to their former positions; (3) freedom of movement must be created in eccentric movements; and (4) multiple occlusal contacts must be provided in centric and eccentric positions. We have described a method that incorporates these basic concepts and provides a harmonious occlusal arrangement for both edentulous and partially edentulous class II patients.

Dental Occlusion, Balanced↗
PubMed1988

Occlusal considerations for partially or completely edentulous skeletal class II patients. Part I: Background information.

Although approximately 15% of the population may be classified as having the skeletal class II relationship, this group of patients is far from homogeneous. Two prototypes were used to delineate various problems in the prosthodontic occlusion that dentists may encounter with these patients. A satisfactory occlusion is difficult to achieve because of skeletal discrepancies, limited space for occlusal contact, steep guidance factors, and the necessity for multiple eccentric occlusal contacts because of the significant range of mandibular motion.

Cephalometry↗
PubMed1987

Neurochemical changes in experimental African trypanosomiasis in voles and mice.

Dopamine, norepinephrine, serotonin and related metabolites were measured in the brain of meadow voles and mice after infection with Trypanosoma brucei gambiense with the goal of understanding the neurochemical changes accompanying infection with this parasite. Serotonin and 5-HIAA levels both fell by 26%, and HVA levels rose by 56%, in vole brains during infection. Dopamine, DHPG and norepinephrine levels, however, remained unchanged. In mice, serotonin levels dropped by 17 and 23%, respectively, in the pons-medulla and midbrain regions after infection; 5-HIAA and dopamine levels remained unaffected by infection in mice. The possible causes and the significance of these changes are discussed.

Animals↗
PubMed1986

Errors incurred in programming a fully adjustable articulator with a pantograph.

The ability of experienced and inexperienced dentists to follow graphic tracings of known value was compared. The mean differences from known values were low for the settings of condylar inclination, progressive side shift, and immediate side shift. Errors were high in both groups when the parameters of the top wall and rear wall were evaluated. Further work is necessary to determine the clinical significance of these errors.

Dental Articulators↗
PubMedDate not supplied

Fracture resistance of endodontically treated teeth restored with bonded amalgam and full crowns.

The use of dentin bonding prior to placement of core build-up restorations has been shown to reduce microleakage and reinforce remaining tooth structure. However, information is lacking about the influence a core build-up has on the fracture resistance of crowned teeth. The purpose of this in-vitro study was to compare the influence of three types of core build-ups on the fracture resistance of crowned teeth.

Analysis of Variance↗
PubMedDate not supplied

Increased interleukin-1 beta in the crevicular fluid of diseased implants.

Diseased implants can be distinguished from healthy implants by the presence of inflammation in the surrounding tissue. Inflammation correlates with elevated levels of interleukin-1 beta in gingival crevicular fluid. An analysis of interleukin-1 beta levels in diseased implants compared to those in matching healthy implants in 12 patients indicates that the level of interleukin-1 beta was approximately three times that at healthy sites. Interleukin-1 beta levels may provide a means of monitoring the health status of dental implants.

Adult↗