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Biomedical subjects

W W Brackett

Publications and source records attributed to W W Brackett.

At least 19 recordsLinked to original sources
PubMed2000

Effect of plasma arc curing on the microleakage of Class V resin-based composite restorations.

PURPOSE: To evaluate the effect of plasma arc light-curing on the microleakage of Class V resin-based composite (RBC). MATERIALS AND METHODS: Facial and lingual Class V cavities were prepared at the cemento-enamel junction of extracted third molars. Restorations of the two materials (Z250; Amelogen) were placed, using the supplied dentin adhesives (Single Bond; PQ 1, respectively), and light-cured by either a halogen light curing unit (H) or a plasma arc curing unit (P). After thermal cycling, the teeth were immersed in methylene blue dye, then sections of the restored teeth were visually assessed for leakage. RESULTS: No leakage was observed at the interface between enamel and RBC in any restoration in this study. At gingival margins, the incidence of leakage (slight/severe) was: Z250 H = 2/4, P = 6/6; Amelogen H = 3/4, P = 1/12, where n = 16. The greatest incidence of leakage was observed in restorations cured by the plasma arc method. A two-way ANOVA of leakage data rankings showed curing method to be a significant factor (P = 0.002), restorative material not to be a significant factor (P = 0.24), and no significant interaction between material and curing method (P = 0.38).

Analysis of Variance↗
PubMed1999

1-year clinical evaluation of Compoglass and Fuji II LC in cervical erosion/abfraction lesions.

PURPOSE: This study was undertaken to compare the clinical performance of a polyacid-modified resin-based composite and a resin-modified glass-ionomer restorative material over 1 year. MATERIALS AND METHODS: Thirty-four pairs of restorations of Compoglass (C) and Fuji II LC (F) were placed in 31 patients, with no patient receiving more than two pairs, and with materials assigned at random within the pairs. Caries-free cervical erosion/abfraction lesions of the facial surface were restored without tooth preparation according to manufacturers' instructions, except that tooth structure to be restored was etched with 37% phosphoric acid prior to placement of Compoglass. Restorations were clinically evaluated by two blinded examiners at baseline, 6 months, and 1 year, using modified Ryge/USPHS criteria. Restorations receiving a score of "Charlie" in either retention or secondary caries were classified as failed restorations. The incidence of failures was statistically analyzed as a pairwise comparison, using an exact binomial test. RESULTS: Thirty-one pairs of restorations were available for recall at 1 year. The percentage of Alfa scores for each material in each category were: Retention (C = 84%, F = 100%), Color match (C = 81%, F = 100%), Marginal discoloration (C = 78%, F = 97%), Secondary caries (C = 88%, F = 100%), Anatomic form (C = 92%, F = 100%), and Marginal adaptation (C = 26%, F = 46%). Except for the failed restorations, no other Charlie scores were assigned. A significant difference in the incidence of failed restorations was found between the materials (P = 0.01).

Adult↗
PubMed1998

Microleakage of Class V compomer and light-cured glass ionomer restorations.

STATEMENT OF PROBLEM: Resin-modified (light-cured) glass ionomer and polyacid-modified composite resin (compomer) restorations are popular choices for the restoration of root caries and cervical abrasion/erosion lesions, but clinical studies are relatively few and have been published primarily as abstracts. PURPOSE: In the absence of adequate clinical data, the marginal integrity of restorations of the above two types of material was compared in vitro. The microleakage of restorations of two light-cured glass ionomer restorative materials and of one compomer material was evaluated. METHODS AND MATERIAL: Restorations of the three materials were placed in facial and lingual Class V cavity preparations in bovine incisors. All preparations were centered on the cementoenamel junction and were prepared with 45-degree enamel bevels. After thermal cycling, teeth were immersed in methylene blue dye, then sections of the restorations (n = 16) were visually evaluated. RESULTS: Dye penetration was observed at approximately 20% of restoration margins for all three materials, with the greatest incidence of severe leakage in the compomer restorations. CONCLUSION: No significant difference in microleakage among the three materials (ANOVA; p > 0.05) was found.

Animals↗
PubMed1997

Effect of finishing method on the microleakage of Class V resin composite restorations.

PURPOSE: To evaluate the effect of three finishing methods on the microleakage of Class V hybrid resin composite. MATERIALS AND METHODS: Facial and lingual Class V cavities were prepared at the cemento-enamel junction of bovine incisors. Restorations of the two materials (Z100; Prodigy) were placed, using the supplied dentin-adhesives (Scotchbond Multipurpose; OptiBond FL, respectively). Finishing methods were carbide (C) and diamond (D) finishing instruments operated at high-speed, and finishing disks (S). After thermal cycling, the teeth were immersed in methylene blue dye, then sections of the restored teeth (n = 12) were visually assessed for leakage. RESULTS: No leakage was observed at the resin-enamel interface in any restoration. At gingival margins, the incidence of leakage (slight/severe) was: Z100 D = 4/3, C = 5/3, S = 2/0; Prodigy D = 3/0, C = 2/4, S = 3/2. The greatest incidence of leakage was observed in restorations finished with carbide finishing burs. A two-way ANOVA of leakage data rankings showed no significant difference among the three methods (P = 0.07) or between the two materials (P = 0.55), and no significant interaction of material and finishing method (P = 0.07).

Analysis of Variance↗
PubMed1996

The effect of etchant and cement age on the adhesion of resin composite to conventional and resin-modified glass-ionomer cements.

The effects of etching with maleic or phosphoric acid on the adhesion of resin composite to resin-modified glass-ionomer cement restorative materials were evaluated through a shear bond test. These effects were determined with both recently set and aged cement. For the three resin-modified materials tested, compared to no etching, the two etchants improved or did not affect the adhesion of resin composite, regardless of the age of the cement. For a chemically cured material, included in the study as a control, the same effects were observed, except that etching of the recently set cement with maleic acid was detrimental to adhesion.

Acid Etching, Dental↗
PubMed1995

Microleakage of light-cured glass-ionomer restorative materials.

The microleakage of three glass-ionomer restorative materials, one chemically cured and two light cured, was evaluated. Ten restorations of each material were placed, according to manufacturer's instructions, in Class V cavities in bovine incisors. All cavities were prepared with 90-degree cavosurface margins and were located at the cementoenamel junction. Sectioning of the teeth after thermocycling and immersion in methylene blue dye revealed only occasional slight leakage and no statistically significant difference among the three materials.

Analysis of Variance↗
PubMed1994

Performance of a glass ionomer luting cement over 8 years in a general practice.

For this report, 1230 cast restorations luted with a glass ionomer cement were followed up for 8 years. The results show an absence of secondary caries, 99% retention of restorations, and a 4% incidence of irreversible pulpitis. The infrequent thermal sensitivity previously observed after cementation in this group of restorations did not recur.

Biocompatible Materials↗
PubMed1994

The etiology and treatment of cervical erosion.

Erosion lesions are probably caused by a number of factors in combination. Symptomatic treatment is most indicated for lesions too shallow to restore. For the restoration of erosion, glass ionomer materials, because they eliminate the risk of secondary caries, remain the material of choice, although dentin-adhesive resins have been continuously improved. Recent light-cured glass ionomer restorative materials can be placed without most of the inconvenience inherent in earlier chemically cured materials, and like their chemically cured predecessors, can be veneered with composite resin to improve the esthetics of highly visible restorations.

Composite Resins↗
PubMed1992

Performance of a glass ionomer luting cement over 5 years in a general practice.

Over a 5-year period, 1435 teeth in patients under recall in a general dental practice have received cast restorations luted with a glass ionomer cement. The material has demonstrated an exceptionally low rate of secondary caries, excellent retention of castings, and acceptable compatability with the dental pulp.

Cementation↗
PubMed1989

Repair of glass ionomer restorative materials: flexure strength of specimens repaired by two methods.

This study evaluated the adhesion of newly mixed glass ionomer restorative materials to set materials. The flexure strength of specimens formed by the addition of new material to week-old material by using two different surface treatments was compared with the flexure strength of solid specimens that were 1 week old. All repaired specimens attained at least 44% of the average strength of unrepaired specimens of the same material. Repairs made with a combination of unlike materials were not significantly different from most repairs with like materials. For all materials collectively, repairs made with a 37% phosphoric acid pretreatment were significantly stronger than repairs made with a 40% polyacrylic acid pretreatment.

Acid Etching, Dental↗
PubMed1989

Relative microhardness of glass ionomer restorative materials as an indicator of finishing time.

Microhardness was evaluated as an indicator of appropriate finishing intervals for glass ionomer restorative materials. The hardness of several materials was determined after the first hour of mixing. A material clinically documented to be satisfactorily finished after a delay of 15 minutes attained 29% of its 24-hour hardness during that interval. Samples of the other materials finished on reaching this relative hardness, which differed from the manufacturers' suggested finishing delays, showed no differences in surface characteristics, appearance, or surface roughness compared with specimens finished at the recommended times.

Aluminum Silicates↗