PubMed Health⌕ Search

Biomedical subjects

S O Hondrum

Publications and source records attributed to S O Hondrum.

At least 37 records · Page 2Linked to original sources
PubMed1991

The U.S. Army Institute of Dental Research dental materials shelf-life survey: lot request results.

In an attempt to determine the age of perishable dental materials used at any one time in U.S. Army dental care facilities, a questionnaire was distributed to each U.S. Army Dental Activity supply point. Results reveal that almost half of commonly used perishable dental restorative materials are older than the expiration date, determined by the manufacturer's shelf-life, at the time of use. Materials used in OCONUS facilities are generally several months older than materials within CONUS facilities. Supply personnel could not determine the shelf-life of perishable restorative dental materials from package information in over 25% of all entries.

Dental Materials↗
PubMedDate not supplied

Interim dentures for the older patient who is medically compromised.

The concept of interim or transitional dentures is appropriate to the treatment of older patients who are hospitalized or medically compromised. This paper briefly reviews the emotional and physiological needs of these patients, and illustrates a case in which an interim denture technique was beneficial.

Dental Care for Persons with Disabilities↗
PubMedDate not supplied

Comparison of 10% carbamide peroxide and sodium perborate for intracoronal bleaching.

The purpose of this study was to compare 10% carbamide peroxide to the combination of sodium perborate and water as intracoronal bleaching agents. Forty-four extracted teeth were discolored in vitro. Bleaching agents were placed intracoronally to the level of the cemento-enamel junction for 12 days; solutions were replaced after four and eight days. Standardized slides were used to rank color changes; a colorimeter was used to quantify color change. After 12 days, 65% of the discolored teeth in the 10% carbamide peroxide group and 67% of the discolored teeth in the sodium perborate group had lightened to their original shade or lighter. While there was no statistical difference between the two treatments, sodium perborate was easier to use.

Borates↗
PubMedDate not supplied

Effects of evaporation on the properties of water-based dental luting agents.

The most commonly used luting agents for fixed prosthodontics are water-based cements: zinc phosphate, zinc polycarboxylate, glass ionomer, and resin-modified glass ionomer. Properties were tested at baseline and after the cement liquids were allowed to evaporate for 10, 20, and 30 minutes. Viscosity, pH, contact angle, and surface tension were determined using the cement liquids only; tensile strength, hardness, film thickness, and working/setting times were determined after the cements had been mixed with the various liquids. pH decreased over 30 minutes, while viscosity, contact angle, and film thickness all increased, especially for the zinc polycarboxylate and glass ionomer cements. Changes in mechanical properties depended upon time and material.

Analysis of Variance↗
PubMedDate not supplied

A comparison of commercially available mouthguards and a custom mouthguard.

Participation in sporting events involves a risk of injury to the teeth and surrounding structures. The purpose of this study was to compare the properties of a custom mouthguard and three commercially available mouthguards. Tests included rebound upon impact as well as incisor thickness and hardness after fabrication. Results revealed that all three commercially available mouthguards exhibited greater rebound than the custom mouthguard. Rebound was related directly to the thickness of the mouthguard in the incisor region. The thickness of a mouthguard may be critical to avoiding injury to the teeth and surrounding structures.

Analysis of Variance↗
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↗
PubMedDate not supplied

Resin bonding to primary teeth using three adhesive systems.

In vitro bond strengths of three resin adhesive systems were tested using 111 primary teeth. Ninety-six flat dentin surface specimens were divided into six groups consisting of 16 primed or 16 unprimed samples for each adhesive system. The remaining 15 tooth samples were divided into three groups of five to determine each adhesive system's bond strength to primary etched enamel. Resin buttons were polymerized to all specimens with visible light, thermocycled for 2000 cycles between 5 and 55 degrees C, and shear bond strength was measured with a Instron Testing Machine (Instron Engineering Corp, Canton, MA). ANOVA and multiple comparison tests showed that Optibond Multiuse Bonding Agent had a statistically greater mean shear bond strength to primary dentin (20.5 +/- 3.5 MPa) than Prisma Universal Bond 3 Multi-purpose Bonding System (9.1 +/- 4.4 MPa), Scotchbond Multi-purpose Dental Adhesive System (7.3 +/- 3.7 MPa), and primary etched enamel (9.8 +/- 4.4 MPa) at P < 0.05. This study demonstrated that resin adhesive systems may achieve bond strengths to primary dentin comparable to those of primary enamel, and that these bonds may be as strong as bonds to permanent enamel and dentin. These adhesive systems may allow more confident esthetic restoration of primary anterior teeth.

Acid Etching, Dental↗
PubMedDate not supplied

In vitro evaluation of an adhesive monomer as a bonding agent for orthodontic brackets to primary teeth and nickel-chromium ion crowns.

The adhesive monomer, Clearfil New Bond, was used to enhance the bond strength between orthodontic brackets and primary molars, premolars, and NiCr crowns. Twenty specimens of each had this dental adhesive applied according to the manufacturer's instructions in addition to a chemically cured composite material. The remaining specimens (20 each) were bonded without the adhesive monomer. Shear bond strengths were determined using a universal testing machine. Fracture sites were examined to determine the type of bond failure. All bond strengths were significantly increased with the addition of Clearfil New Bond (P < or = 0.0001). The shear bond strength to NiCr crowns with the addition of the adhesive monomer was 7.76 kg. This is comparable to the shear bond strength observed for primary molars (8.66 kg) and premolars (8.65 kg) without adhesive monomer. The observed decrease in adhesive bond failures with the addition of Clearfil New Bond indicated a stronger shear bond strength between the tooth surface and the bracket base. Clearfil New Bond can significantly increase the shear bond strength of orthodontic brackets to both primary molars and premolars. Additionally, it was shown that orthodontic brackets can be successfully bonded to Ni-Cr crowns at strengths comparable to primary or permanent enamel.

Analysis of Variance↗
PubMedDate not supplied

Tear and energy properties of three impression materials.

A dental impression material must have sufficient strength to allow removal from a gingival sulcus without tearing; it must also have adequate elastic recovery. This study examined the tear energy, the permanent deformation upon extension, the energy absorbed to an estimated point of significant deformation, and the extent of permanent deformation at tear of polysulfide, polyether, and addition-reaction silicone impression materials. As expected, polysulfide material had a higher tear energy and strain at tear than either polyether or addition-reaction silicone materials. However, the more relevant clinical properties, such as energy absorbed per amount of deformation and tear at a point of minimal permanent deformation, favored the addition-reaction silicone material, followed by the polyether material.

Analysis of Variance↗
PubMedDate not supplied

Effect of sterilization on stiffness and dimensional stability of rubber-dam clamps.

Simulated clinical conditions were used to test the effect of sterilization on rubber-dam clamp stiffness and dimension. Sixty Hygienic and Ivory W7 clamps were either steam or dry heat sterilized and compared to controls. Stiffness and dimensional change between Ivory clamp groups was significant (p<.0001); the sterilized clamps showed less change than the controls. Hygienic groups showed a significant different between the control and dry heat groups (p<.05); the sterilized clamps showed less change than the controls. The change in stiffness and interjaw width for all Ivory clamps compared to all Hygienic clamps was significant (p<.0001). The Hygienic clamps changes less than the Ivory clamps. The results indicate that steam and dry heat sterilization do not affect retention of rubber-dam clamps.

Analysis of Variance↗
PubMedDate not supplied

Microleakage under amalgam restorations lined with Copalite, Amalgambond Plus, and Vitrebond.

To evaluate the effectiveness of 3 cavity-preparation lining agents in reducing microleakage under amalgam restorations, the apices of 64 human molars were sealed with amalgam, and Class V preparations were placed. Following storage and thermocycling, the molars were placed in acid fuchsin for 24 hours, then sectioned longitudinally. Ranked data were used to score dye penetration. A Kruskal-Wallis statistical test was used to compare the three groups to the control. Teeth treated with glass ionomer cement showed a statistically significant increase (p = .0227) in dye penetration. Dye penetration increased when Amalgambond Plus and glass ionomer resin liner were placed under amalgam restorations. No difference in dye penetration was observed when Copalite was applied. Results of this study do not support routine use of these agents under amalgam restorations for control of microleakage.

Calcium Hydroxide↗
PubMedDate not supplied

Effect of heat treatment on stainless steel lingual arch appliances.

This study evaluated the effect of heat treatment on 0.036" diameter stainless steel wire. Forty wires were bent into arch forms (20 experimental and 20 control). The arch width changes were measured and the forces generated were determined over an eight week period. Heat treatment resulted in immediate and significant expansion (p < 0.001) followed by stabilization of arch width. The control wires continued to expand throughout the study. The force generated by the control group and experimental group expansion was capable of producing tooth movement.

Compressive Strength↗
PubMedDate not supplied

Contouring, finishing, and polishing Class 5 restorative materials.

Three materials used for class 5 restorations (composite resin, glass ionomer, and resin-modified glass ionomer) were contoured, finished, and polished using seven methods: Matrix only, Sof-Lex disks, Composite Finishing System, Enhance Finishing/Polishing System. Two Striper MFS/MPS System. Two Striper MPS polish only, and contouring burs only. Results were quantified by surface roughness and gloss (reflectance). The glass-ionomer material was rougher and less reflective than composite resin; the smoothness and gloss of the resin-modified glass ionomer were between these two extremes. The original matrix smoothness and gloss could not be reproduced with any of the contour/finish/polish techniques tested on any of the three materials. The smoothest surfaces were achieved using a sequential series of rotary abrasive instruments.

Analysis of Variance↗