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Biomedical subjects

D J Bales

Publications and source records attributed to D J Bales.

At least 19 recordsLinked to original sources
PubMed1992

Clinical performance of posterior composite resin restorations.

Two formulations of posterior composite resin (P-30 and Bisfil-P) were evaluated and compared to a high-copper, dispersed-phase amalgam (Dispersalloy). One hundred twenty-eight restorations were placed in 27 patients so that each patient received at least one of each material. After 3 years of clinical service, all three restorative materials produced clinically acceptable restorations, according to US Public Health Service and Leinfelder criteria. The amalgam restorations, however, underwent less wear (44 microns) than did the posterior composite resin restorations (60 to 74 microns). Stratification of data by type of tooth, class of restoration, and size of restoration produced the same ranking of wear from lowest to highest: Dispersalloy, Bisfil-P, and P-30. Resin restorations showed 45% more wear in molars than in premolars, and more wear was associated with moderately sized restorations than with conservative restorations. The surface texture of restorations of composite resin with porous strontium glass filler was nearly as smooth as that of enamel and was significantly smoother than that of the restorations of composite resin with zinc glass filler or of unpolished amalgam.

Analysis of Variance↗
PubMed1992

Clinical evaluation of high-copper dental amalgams with and without admixed indium.

High-copper amalgam alloys containing 5% and 10% admixed indium, shown in previous studies to have improved properties and acceptable biological behavior, were evaluated in a clinical study designed to examine factors relating to clinical success. One hundred and seventy-five Class I and Class II amalgam restorations were placed in 25 patients. Each patient received all three dispersed-phase amalgams tested: without indium (Dispersalloy), with 5% indium (Indisperse 5), with 10% indium (Indisperse 10). After 30 months, 22 patients were recalled and 146 restorations evaluated. The margins of the indium-containing amalgam restorations incurred slightly less marginal breakdown, an effect that could be attributed to the addition of admixed indium and to the increase in silver-copper eutectic spheres which is found in these alloys. These amalgams also demonstrated a slightly darker appearance, and were slightly rougher than the non-indium-containing amalgam. These differences were minor; at 30 months, all restorations were well within the clinically acceptable range for each parameter evaluated.

Analysis of Variance↗
PubMed1991

Marginal adaptation of castable ceramic crowns.

Tooth preparations and seating techniques of castable ceramic crowns differ from metal ceramic crowns. This study evaluated the variable effects of cementation on the marginal adaptation of Dicor, Cerestore, and porcelain-fused-to-metal crowns. The shoulder preparation was maintained for ceramic crowns, and a cavosurface bevel was designed for metal ceramic crowns. Crowns were made with a replication size of 10, placed on master dies, and the marginal openings measured with a Nikon Measurescope 20 instrument. Thirty crowns were cemented with zinc phosphate cement and the recommended clinical force. Marginal adaptation was not improved with a gingival bevel preparation or an increased seating force. The best marginal adaptation was recorded for Cerestore crowns.

Aluminum Oxide↗
PubMed1991

Tooth bleaching: its effect on oral tissues.

After investigating the literature, we suggest these guidelines for tooth bleaching: If bleaching solutions of high concentration are used, prevent accidental exposure of gingival tissues to the solutions by use of a rubber dam. If using lower concentrations of bleaching solutions, avoid long-term exposures to gingival tissues. To maintain pulp vitality, keep bleaching time and temperatures to a minimum. Check teeth for exposed dentin and enamel fractures. Advise patients that thermal sensitivity may occur after the bleaching procedure and may persist for several days. Prescribe premedication with an anti-inflammatory drug, when necessary. Avoid bleaching the cervical area of the tooth by covering the area with a base to avoid cervical resorption. Avoid dentin exposure by noting that abrasive bleaching techniques can remove significant amounts of enamel. Take special care when bleaching enamel--especially near the cervix of the tooth, where the enamel is thin.

Dental Enamel↗
PubMed1989

Effect of admixed indium on mercury vapor release from dental amalgam.

The purpose of this study was to evaluate the effect of admixed indium on the amount of mercury vapor released from dental amalgam. We made amalgam specimens according to ADA Specification Number 1. We added various amounts (0-14% by weight) of indium to the alloy powder. We also tested the commercial amalgams Dispersalloy, Valiant, and Indiloy. Specimens were held at 37 degrees C and 100% humidity. We used a Jerome Mercury Vapor Analyzer (model 411) to measure the mercury vapor released. We analyzed the data by means of ANOVA and Student-Newman-Keuls procedures. Admixed indium significantly decreased the amount of mercury vapor released from dental amalgams; the period of the greatest effect on mercury vapor released was during the setting phase of amalgam; and dental amalgams with greater than or equal to 8% admixed indium released the least amount of mercury vapor.

Air Pollutants↗
PubMed1979

Arthrotomography of the temporomandibular joint: new technique and preliminary observations.

A technique for arthrography of the temporomandibular joint using multidirectional tomography is described that greatly simplifies interpretation. In 21 attempts, 20 successful arthrograms were obtained in patients complaining of pain, tenderness, and clicking and locking of the joint who had not responded to conservative therapy. Abnormalities demonstrated were perforation of the meniscus, anterior dislocation and subluxation of the meniscus; and redundancy of the bilaminar zone. In all 11 patients who underwent surgical meniscoplasty, disc abnormalities included thinning, perforation, flaccidity, and bilaminar redundancy. No permanent complications of the arthrographic procedure occurred, but temporary postprocedure discomfort was frequent. This preliminary experience with temporomandibular joint arthrotomography suggests this easily performed procedure offers reliable information about disc function and integrity that may assist in a selection of patients for meniscoplasty and other surgical treatment.

Adolescent↗
PubMed1979

Arthrotomographic evaluation of the temporomandibular joint.

Thirty-five arthrotomograms of the temporomandibular joint (TMJ) were done on 33 patients who had chronic pain and dysfunction of the TMJ. All patients were refractory to conservative treatment. Five arthrotomograms were normal; abnormalities were observed in 30. Abnormalities of the meniscus were anterior dislocation, anterior subluxation, perforation, tenting, and degenerative changes and adhesions. The significance of these abnormalities is discussed. Arthrotomography was found to be an integral part of the diagnosis and treatment of TMJ disorders.

Adolescent↗
PubMedDate not supplied

Effect of admixed indium on the clinical success of amalgam restorations.

The purpose of this study was to clinically evaluate two formulations of a dispersed-phase, high-copper dental amalgam alloy (Indisperse), which contained admixed indium. One alloy tested contained 5% indium, and the second alloy contained 10% indium. A similar alloy without indium, Dispersalloy, was also placed for comparison. Over the course of the five-year study, there were no differences clinically or statistically regarding texture and luster. The margins of the restorations containing indium incurred slightly less fracture than the non-indium-containing restorations; however, these differences were not clinically significant. It can be concluded that the admixture of 5-10% indium as well as the increased ratio of eutectic spheres to lathe-cut particles found in the indium alloys enhance the clinical performance of amalgam restorations.

Dental Amalgam↗