Biomedical subjects

J C Meiers

Publications and source records attributed to J C Meiers.

42 records · Page 3Linked to original sources

PubMedDate not supplied

Shear bond strength of resin to acid/pumice-microabraded enamel.

The effect of enamel microabrasion techniques consisting of either 18% hydrochloric acid in pumice or a commercially available abrasive/10% hydrochloric acid mixture, PREMA, on composite/enamel shear bond strengths was investigated. Sixty extracted third molars had the bonding surface flattened and were divided into six treatment groups (n=10) with the enamel treated prior to bonding as follows: Group 1-- untreated; Group 2--37% phosphoric acid etched for 30 seconds; Group 3--18% hydrochloric acid/pumice mixture applied for five 20-second treatments; Group 4--similar to Group 3 with additional 37% phosphoric acid etch; Group 5--treated with PREMA compound applied for five 20-second treatments; Group 6--similar to Group 5 treatment with additional 37% phosphoric acid. Herculite XR composite resin was then bonded to all samples using a VLC unit. Samples were tested in shear, and fractured enamel surfaces were evaluated using light microscopy to determine the enamel-to-resin failures. Resin bond strengths to microabraded and H3PO4-etched enamel were similar to bond strengths of untreated H3PO4-etched enamel and were significantly better than bond strengths to PREMA-treated or unetched enamel.

Acid Etching, Dental↗

PubMedDate not supplied

Cavity disinfectants and dentin bonding.

The purpose of this study was to examine the effect on microleakage of two disinfectants, one chlorhexidine based and the other I2-KI/CuSO4 based, used as cavity washes prior to the application of the dentin bonding systems Tenure and Syntac in class 5 composite restorations. Class 5 cavity preparations were placed on extracted molars with occlusal margins in enamel and gingival margins in cementum. Preparations were treated with either Syntac or Tenure, combinations of one of the two disinfectant washes with Syntac or Tenure, or with one of the disinfectants only and filled with Tetric composite. Samples were thermocycled, stained, and sectioned to evaluate dye penetration. The chlorhexidine-based wash did not significantly affect microleakage when compared to the Tenure and Syntac controls, while the I2-KI/CuSO4-based wash resulted in significantly higher gingival microleakage when used with Syntac. The use of cavity disinfectants with composite resin restorations appears to be material specific regarding their interactions with various dentin bonding systems' ability to seal dentin.

Analysis of Variance↗

PubMedDate not supplied

Surface roughness of light-activated glass-ionomer cement restorative materials after finishing.

The purpose of this study was to compare the effect of various finishing sequences on the surface roughness of four new light-activated (LAGIC) restorative materials. Restorative materials included a polyacid-modified composite resin (Variglass VLC) and three resin-modified glass-ionomer cements (Vitremer, Photac-fil, and Fuji II LC). Thirty specimens of each material were prepared in Macor dies and randomly divided into six finishing sequence groups (n = 5): (1) Mylar strip (control), (2) carbide bur/Sof-Lex XT disks, (3) ET finishing diamonds, (4) carbide bur/Enhance polishing system, (5) carbide bur/Politip rubber finishers, and (6) carbide bur alone. Average surface roughness (Ra) in micrometers was measured with a Mitutoyo Surftest 401 Surface Roughness Tester and the data compared using ANOVA, Student-Newman-Keuls Multiple Comparison tests, and Dunnett's test at P < or = 0.05. Surface topography was also assessed using the scanning electron microscope (SEM) on epoxy replicas from samples of each group. The Mylar strip produced the smoothest surface and finishing sequences; (2) and (3) were significantly smoother than (4), (5), and (6). There were no significant differences between restorative materials when all finishing sequences were combined. SEM analysis was consistent with the profilometer results. Materials with higher (Ra) values appeared to have rougher surfaces. Rubber abrasives and polishing pastes seem to preferentially remove the polysalt and resin matrix of these materials.

Acrylic Resins↗

PubMedDate not supplied

Effect of dentin primer on the shear bond strength between composite resin and enamel.

The purpose of this investigation was to determine the effect of dentin primers from Scotchbond Multi-Purpose, ProBond, All-Bond 2, and Syntac on the shear bond strength of composite resin to etched enamel. Two groups of extracted human molar teeth with flattened enamel surfaces (n = 12) were randomly assigned to each enamel/dentin bonding system. Following manufacturers' instructions enamel surfaces were etched, rinsed, and dried. Composite bonding procedures were conducted similarly in both groups for each enamel/dentin bonding system, except that in one of the two groups, dentin primer was applied prior to adhesive resin and composite placement. Samples were thermocycled and tested in shear until failure. Fracture analysis was performed on enamel surfaces with both light and scanning electron microscopy. Shear bond values (Mean +/- SD, MPa) were: Scotchbond Multi-Purpose unprimed 22.4 +/- 3.2, primed 17.9 +/- 5.9; ProBond unprimed 19.4 +/- 6.2, primed 18.3 +/- 3.3; All-Bond 2 unprimed 19.0 +/- 3.6, primed 17.3 +/- 3.0; and Syntac unprimed 26.2 +/- 9.0, primed 22.0 +/- 5.4. The only significant difference found between primed and unprimed groups was with Scotchbond Multi-Purpose, though there was a trend for primer application to decrease enamel bond strengths. Fracture surface analysis revealed that most failures were cohesive within the composite resin. These data suggest that the effect of primer on bonded composite resin to etched enamel is material specific.

Analysis of Variance↗

PubMedDate not supplied

Antibacterial activity of dentin bonding systems, resin-modified glass ionomers, and polyacid-modified composite resins.

The antibacterial effects of the dentin bonding systems Syntac, ProBOND, Gluma 3-Step, the resin-modified glass ionomers Photac-Fil, Fuji Lining LC, Fuji II LC, and the polyacid-modified composite resins VariGlass, Geristore, and Infinity were evaluated using the cariogenic bacteria S mutans, L salivarius, S sobrinus, and A viscosus in vitro with a modified cylinder drop plate agar diffusion assay. All glass ionomers, the polyacid-modified composites, and the primers and adhesives of the dentin bonding systems exhibited various degrees of antibacterial activity against most of the test bacteria. The antibacterial activity of the adhesives of dentin bonding systems was anticipated because of the glutaraldehyde used in their formulations. However, the antibacterial activity of the various primers was unexpected and indicates a dual antibacterial action of these systems.

Acrylic Resins↗

PubMedDate not supplied

Microleakage of dentin/amalgam alloy bonding agents: results after 1 year.

The purpose of this study was to evaluate the 1-year results of the dentin bond (DBS)/viscous resin liner combinations Amalgambond Plus, Tenure/Panavia, Syntac/Dual Cem, and All-Bond 2/Liner F in reducing microleakage in class 5 cavity preparations restored with an admixed or a spherical amalgam alloy and to compare these results to the previously reported short-term (4-day) data from this same study. Class 5 cavity preparations with occlusal margins in enamel and gingival margins in cementum were prepared on extracted human molar teeth. Prepared teeth were distributed randomly into 12 treatment groups (n = 10) consisting of the various DBS/ liners, Copalite, and no liner for each alloy. Samples were stored in saline for 12 months, thermocycled, and stained with dye. Restorations were sectioned and microleakage scored. The DBS/liner combinations, with the exception of Syntac/Dual Cem, had significantly less microleakage with both alloys than Copalite or no liner. Comparing short-term to long-term results within the DBS/liners, only Tenure/ Panavia with Tytin had a significant increase in microleakage scores. These data indicate DBS/ liner combinations can provide significant protection against microleakage under high-copper amalgam alloys for up to 1 year.

Analysis of Variance↗