PubMed Health⌕ Search

Biomedical subjects

W J Finger

Publications and source records attributed to W J Finger.

At least 19 recordsLinked to original sources
PubMed2005

Volatilization of components from and water absorption of polyether impressions.

OBJECTIVE: To evaluate the accuracy of stone dies produced from impressions with polyether impression materials and a vinyl polysiloxane reference material after prolonged storage at 0, 50, or 100% relative humidity. METHODS: Impressions were taken with light and heavy-bodied types of the polyethers P2 (P2L/H; Heraeus Kulzer) and Impregum (IML/H; 3M ESPE) and vinyl polysiloxane Flexitime (FLL/H; Heraeus Kulzer) from a truncated steel master cone in cylindrical trays giving 4 mm layer thickness at the prominence line. Impressions were taken at 23 degrees C, and stone dies were poured after 1, 2, 3, 4, or 5 days storage at 23 degrees C and 0, 50, or 100% RH. Accuracy was determined as discrepancy between a steel ring with accurate fit on the master cone and the stone die and expressed as base diameter deviation Deltad (microm). One-way ANOVA and Duncan's post-hoc test were used for statistical data analysis (p<0.05). RESULTS: P2L/H showed significant Deltad increase (30-240 microm) depending on storage time and humidity (p<0.05). Dies from IML/H at 0% RH were 90 through 180 microm enlarged, at 50% RH the maximum diameter increase was 60 microm, and at storage in 100% RH all dies were 25-120 microm smaller (p<0.05). Dies from FLL/H showed maximum Deltad deviations (55 to -10 microm). CONCLUSIONS: P2 impressions release volatile substances during storage and should preferably be poured within less than 24 h. Impregum absorbs water and should be stored at <50% humidity. The accuracy of Flexitime is scarcely affected by storage time or by ambient humidity.

Absorption↗
PubMed2001

Self-etching primers--an alternative to the conventional acid etch technique?

MATERIAL AND METHODS: The aim of the present in vitro study was to evaluate the bonding capacity of three self-etching primers (Clearfil SE Bond [SE], Clearfil Liner Bond 2V [CLB], Novabond [NOVA]) to enamel. Two adhesive systems with a separate phosphoric acid etching procedure (Gluma Comfort Bond [GLU], Kurasper F [KU]) served as controls. 60 human incisors were used to evaluate shear bond strengths of composite cylinders to enamel. RESULTS: Significant differences were found between the groups (p < 0.001). The mean value for groups GLU, KU, CLB and SE was 24 MPa. The shear bond strength recorded for the Novabond system was significantly lower (17 MPa). CONCLUSION: The results of the present investigation indicate that enamel bonding especially with the self-etching primers CLB and SE is as effective as conventional phosphoric acid etching.

Acid Etching, Dental↗
PubMed2001

Microtensile bond strength evaluation of three adhesive systems in cervical dentin cavities.

PURPOSE: To evaluate the influence of the orientation of dentinal tubules on the bonding performance, microtensile bond strengths (MTBS) to dentin in cervical dentin cavities were measured for three current bonding systems. MATERIALS AND METHODS: Wedge-shaped cervical cavities (5 x 5 x 3 mm) prepared in extracted human premolars were treated with one of the three adhesive systems, Gluma One Bond, UniFil Bond and Mega Bond in combination with a hybrid-type resin composite. After storage in water for 24 h, the teeth were sectioned longitudinally through the restoration for determination of MTBS, either at the coronal or at the apical wall of the lesion. In an additional group, either the coronal or the apical walls were coated with vaseline prior to adhesive bonding and insertion of the resin composite, and then MTBS was measured. RESULTS: MTBSs (mean +/- SD, MPa) to coronal and apical dentin were 35.1 +/- 19.1 and 16.4 +/- 7.9 for Gluma One Bond, 37.7 +/- 11.5 and 18.6 +/- 8.6 for UniFil Bond, and 27.0 +/- 15.2 and 30.3 +/- 17.0 for Mega Bond, respectively. MTBS to the coronal wall was higher than to the apical wall (p < 0.05) with Gluma One Bond and UniFil Bond, whereas no difference was found with Mega Bond. With all three systems, vaseline coating had no effect on the bond strength (p > 0.05), indicating that the wall-to-wall contraction stresses exerted in the noncoated group had no influence on the bond strength generated. CONCLUSION: In cervical dentin cavities, apart from the individual adhesive's bonding capacity, the dentinal tubular orientation may have an influence on the bond strength.

Adhesives↗
PubMed2001

4-META as an acidic monomer in an all-in-one experimental adhesive.

This article describes a clinical study of an experimental, all-in-one, self-etching priming enamel and dentin adhesive. This new compound is a hydroxyethylmethacrylate (HEMA)-free resin mixture of urethane dimethacrylate (UDMA) and 4-methacryloxyethyl trimellitate anhydride (4-META) dissolved in acetone and water. The pH of the adhesive solution is 2.2, which classifies this material as moderately strong. Bond strengths to enamel and dentin are approximately 20 MPa. The marginal inspection of bonded resin composite restorations in 3.5-mm wide, cylindrical, butt-joint dentin cavities reveals gap-free intact margins in 6 of 8 cases. Scanning electron microscopy analysis of the bonding interface to enamel shows a shallow microretentive etching pattern, and dentin is hybridized to a depth of approximately 1 micron. The fracture morphology analyzed on debonded shear strength specimens illustrates cohesive failure in resin close to the enamel and dentin bonding interfaces.

Analysis of Variance↗
PubMed2000

Rewetting strategies for bonding to dry dentin with an acetone-based adhesive.

PURPOSE: The objective of this study was to investigate the effect of rewetting agents on bonding to etched and air-dried dentin. MATERIALS AND METHODS: For shear bond strength testing (SBS), the proximal surfaces of 90 molars were ground on wet SiC paper to prepare them for resin composite bonding with Gluma One Bond (Heraeus Kulzer, Germany). Dentin cavities were cut (Ø 3.5 mm, 1.5 mm deep) in 60 molars and restored with Gluma One Bond/Charisma for evaluation of the marginal performance (MGW). The adhesive was applied on acid-etched and rinsed dentin after the following pretreatment techniques: A: moist; B: 15 s air dried; C through F: 15 s air dried, followed by 30 s rewetting with C: water; D: 35% HEMA; E: Gluma Primer; F: 5% glutardialdehyde; G through J: as C through F, but followed by 15 s air drying. SBS data were analyzed with ANOVA and Tukey's test, and MGW with Kruskal-Wallis and Mann-Whitney U-test (alpha = 0.05). RESULTS: Shear bond strengths of groups A and B were 20.3 and 1.1 MPa, respectively. The Tukey ranking of SBS results was [A=C=D=E] > [C=D=E] > [C=D=I] > H > [F=J] > [B=G]. Groups A, C, D, E, H, and I with 3 or 4 gap-free restorations each showed no differences in MGW (p > 0.05). In contrast, no gap-free specimens were found in groups B, F, G, or J, and marginal gaps were significantly larger (p < 0.05). CONCLUSION: Rewetting of dried dentin with water, 35% HEMA, or Gluma Primer resulted in effective bonding. Excessive drying after rewetting had no compromising effect on adhesion in the HEMA- and GLUMA-primed groups, whereas the water and glutardialdehyde-treated groups showed poor bonding.

Acetone↗
PubMed2000

Postadjustment polishing of CAD-CAM ceramic with luminescence diamond gel.

PURPOSES: (1) to investigate by SEM and profilometry the effectiveness of Luminescence diamond polishing gel on machinable ceramic after adjustment grinding with different grit diamond finishing burs, and (2) to define a simple, time-saving ceramic finishing and polishing technique for clinically satisfactory results. MATERIALS AND METHODS: Discs, 3 mm thick, were cut from Vita Mark II CAD-CAM ceramic and ground to a uniform surface finish on 600 grit wet SiC paper. Five specimens in each of the seven groups below were finished unidirectionally by a sweeping mode with the following Two Striper MFS diamond burs: 1. MF1 (45 microm); 2. MF2 (25 microm); 3. MF3 (10 microm); 4. MF1 + MF2; 5. MF1 + MF3; 6. MF2 + MF3; 7. MF1 + MF2 + MF3. Then, Luminescence diamond polishing gel was dispensed on a mandrel-mounted felt applicator and applied at 10,000 rpm for 60 s, and after dipping in water for another 60-s sequence. Surface roughness was determined for each step with a stylus-fitted surface analyzer. On each specimen five parallel tracings (evaluation length 4.0 mm and cut-off length 0.8 mm) were made 1 mm apart. Ra and Rz values were recorded as roughness parameters. Data was subjected to one-way ANOVA and Tukey's multiple comparison test at a significance level of alpha = 0.05. One additional sample for each grinding and polishing step in each of the seven groups was produced for SEM analysis. RESULTS: Diamond polishing after MF1 finishing reduced Ra and Rz significantly from 1.75 to 0.79, and from 10.0 to 4.09 microm, respectively, whereas the Ra and Rz reduction after MF3 finishing and diamond polishing were from 0.64 to 0.49 and from 4.31 to 1.81 microm. The polished surface roughness of specimens prefinished with MF2 or MF3 burs alone or as the final step after preceding grinding with coarser grits was not significantly different. The average Ra and Rz values were 0.42 microm and 1.73 microm. SEM photographs confirmed the uniformity of the surface finish in these groups. The second polishing sequence did not significantly improve the smoothness obtained with the first cycle.

Analysis of Variance↗
PubMed1999

Bonding efficiency of single-bottle enamel/dentin adhesives.

PURPOSE: To compare the bond strength to dentin of the single-step enamel-dentin adhesive Etch & Prime 3.0 (EP3) to that of two-step systems Clearfil Liner Bond 2 (CL2), which includes a self etching primer and Gluma One Bond (GL1), a one-bottle bonding agent, intended for use with the total etch technique. MATERIALS AND METHODS: Shear bond strength after a 24-hour water storage was determined for 10 specimens each bonded with the three adhesives. Maximum, gap widths were recorded microscopically after a 10-minute water storage along the margins of resin-based composite restorations bonded with each adhesive in cylindrical dentin cavities (3.5 mm wide and 1.5 mm deep). Marginal micro-morphology of the specimens bonded with EP3 was observed with the SEM. RESULTS: EP3 had an enamel bond strength similar to that of the other materials, but its bond strength to dentin was approximately only 50% of the bond strength of the two other adhesives. Similarly, the marginal performance of resin restorations bonded with EP3 in cylindrical dentin cavities was poor (average maximum gap width 5 microns) irrespective of the curing conditions tested with EP3. CL2 showed significantly smaller gaps (2 microns) along the cavity margin than EP3, whereas in the GL1 group in 7 of the 10 restorations inspected perfect gap-free margins were observed. An SEM investigation of different steps throughout the EP3 application and processing gave evidence that the product apparently conditions and wets enamel and dentin quite effectively, and that an approximately 0.5 micron thick hybrid layer is formed as a coupling zone between dentin (intertubular and peritubular) and restorative resin.

Adhesives↗
PubMed1999

Practitioner variability effects on dentin bonding with an acetone-based one-bottle adhesive.

PURPOSE: The objective of this study was to investigate the effect of operator variability on the marginal performance of resin composite restorations bonded with an acetone-base one-bottle adhesive in standardized dentin preparations. MATERIALS AND METHODS: Five general practitioners were recruited for this trial. In the first group, each dentist received six extracted human teeth with dentin preparations (Ø 3.5 mm, 1.5 mm deep), cut in flatground proximal dentin, and original packages of Gluma One Bond adhesive and Charisma resin composite (Heraeus-Kulzer, Werheim, Germany) including instructions for use. For the second group, the operators were orally instructed, emphasizing the importance of the moist technique, before they received another six teeth for restoration with the same materials. Finally, a third group of six preparations was restored in order to evaluate a possible training effect. The restored teeth were stored in a hygrophor prior to removal of excess material and microscopic determination of the maximum marginal gap width (MGW). Statistical analyses were performed with the Kruskal-Wallis and Wilcoxon tests at p < 0.05. RESULTS: Apart from two samples, preparation margins in the first test group showed gaps between 1 and 12 microns. In the second and third groups, 15 and 16 restorations were gap free, respectively. Significant interoperator variation was found in the first group only. Marginal performance of group 1 restorations was significantly inferior to groups 2 and 3, which were not different (p = 0.79). CONCLUSION: Application of the one-bottle adhesive is technique-sensitive and requires meticulous attention to the instructions.

Adhesives↗
PubMed1998

Salivary contamination during bonding procedures with a one-bottle adhesive system.

OBJECTIVE: The effect of salivary contamination of enamel and dentin on bonding efficacy of an experimental one-bottle resin adhesive was investigated. METHOD AND MATERIALS: The adhesive was a light-curing urethane dimethacrylate/hydroxyethyl methacrylate/4-methacryloxyethyl trimellitate anhydride mixture dissolved in acetone. Evaluation parameters were shear bond strength and marginal gap width in a dental cavity. Apart from a control group without contamination (group 1), etched enamel and dentin were (2) contaminated with saliva and air dried; (3) contaminated, rinsed, and blot dried; (4) coated with adhesive, contaminated, rinsed, and blot dried; (5) coated with adhesive, light cured, contaminated, rinsed, and air dried; or (6) treated as in group 5, with additional adhesive application after air drying. RESULTS: There was no negative effect in groups 3 and 4, compared with control. Air drying after salivary contamination (group 2) resulted in low shear bond strengths and wide marginal gaps. Contamination of the cured adhesive layer (groups 5 and 6) had no adverse effect on enamel shear bond strengths, but resulted in 50% reduced dentin shear bond strengths and wide marginal gaps. CONCLUSION: The one-bottle adhesive system is relatively insensitive to salivary contamination, provided that the contamination occurs prior to light curing of the adhesive and is carefully rinsed and blot dried. Salivary contact after adhesive curing must be avoided.

Adhesives↗
PubMed1997

Resin bonding to enamel and dentin with one-component UDMA/HEMA adhesives.

The aim of this study was to investigate the potential of UDMA/HEMA mixtures as priming and sealing components of dental adhesives. The monomers were mixed in weight ratios 100/0, 80/20, 60/40, 50/50, 40/60, 20/80, 10/90, and 0/100, light activated, and dissolved in acetone at equal parts. The 60/40 UDMA/HEMA mixture served as a reference which was modified with 5, 10, 20, and 30 parts 4-MET relative to the mass of the basic monomer mixture. Shear bond strengths (24 h) of resin composite cylinders, bonded with the adhesive monomers on human enamel and dentin, were determined following a total etch technique with phosphoric acid and application of the adhesives in 2 coats on moist tooth surfaces. Average bond strength to enamel was 32 MPa with no difference between the adhesives. On dentin, significantly different bond strengths were found between UDMA (12.9 MPA) and HEMA (19.4 MPa), whereas all binary mixtures' bond strengths were not significantly different (mean 16.2 MPa). Addition of 5 to 20 wt% 4-MET resulted in a significantly increased mean shear bond strength of 22.3 MPa on dentin. At 10%, a maximum mean strength of 25.4 MPa was recorded. It is concluded that mixtures of commonly used polymerizable monomers, characterized by hydrophilic moieties and dissolved in acetone, are promising candidates for effective resin bonding to enamel and dentin, provided application by the moist bonding technique.

Acetone↗
PubMed1997

Closing of dentinal tubules by Gluma desensitizer.

Gluma Dentin Bond is an adhesive system, where the primer contains 5% glutaraldehyde and 35% hydroxyethyl methacrylate. Practitioners have reported a strong desensitizing effect of the Gluma system on dentin. This study, thus, sought to evaluate the effect of this system on dentin using various microscopic techniques. 12 non-restored human molars extracted for prosthodontic reasons were used. Prior to extraction the buccal cusps were removed such that a 2 mm x 2 mm wide dentin surface was exposed. The surfaces were treated in 6 ways: (1) application of Gluma 2 cleanser, Gluma 3 primer to which 0.1% w/v fluorescein was added, and Gluma 4 sealer; (2) as in (1) but treatment with H2O/0.1% w/v fluorescein instead of the Gluma 3; (3) as in (1) but without Gluma 2; (4) as in (1) but with application of 5% glutaraldehyde instead of Gluma 3; (5) as in (1) but without Gluma 4; (6) as in (1) but with application of 35% HEMA/0.1% w/v fluorescein instead of Gluma 3. Following extraction, 1 tooth per procedure was prepared for confocal laser scanning microscopy. The remaining teeth were fixed and prepared for SEM and TEM evaluation. In specimens of procedures (1) and (5), tubular occlusions could be seen to a depth of 200 microm. In specimens of procedure (4) tubular occlusions were found only to a depth of 50 microm. Such occlusions were not seen in control specimens (2), in specimens where the smear-layer had not been removed (3), or following application of HEMA alone (6). It is concluded that glutaraldehyde can intrinsically block dentinal tubules. The septa in the tubules may counteract the hydrodynamic mechanism for dentinal sensitivity.

Adhesives↗
PubMed1997

Effect of cavity design on microleakage of resin-modified glass ionomer restorations.

PURPOSE: To investigate cavity sealing with resin-modified glass ionomer cements (RGIC) and a compomer relative to the design of Class V cavities crossing the CEJ. MATERIALS AND METHODS: Three types of cavities, 6 x 3 x 1.5 mm, were prepared buccally in human molars. Type 1: semicircular with 90 degrees cavo-surface angle; Type 2: as type 1, but with bevelled enamel margin; Type 3: V-shaped. The cavities were restored with the compomer Dyract (DYR), with one of the RGIC, Fuji II LC (FUJ), Photac-Fil (PHF) or Vitremer (VIT), or with the bonded resin composite system Gluma-CPS/Pekafill (GLP) as a reference. Six restorations in each group were finished immediately after curing and thermocycled 1500 between 5 degrees C and 55 degrees C. For Type 1 restorations, another set of six samples was stored in 23 degrees C water for 24 hours. After thermocycling and water storage, respectively, the specimens were immersed in 0.1% fuchsin. Two sections were made through the restoration to register microleakage on the four surfaces produced as depth of dye penetration coronally and apically by scores 0 (no) to 4 (beyond deepest part of cavity). The results were statistically analyzed by cavity type, site, and restorative material using Kruskal-Wallis ANOVA and Wilcoxon's two sample test at P = 0.05. RESULTS: When compared with water storage, thermocycling had no effect on dye penetration with FUJ and PHF, yet more pronounced microleakage at the enamel site was noted with DYR and VIT, and apically with DYR and GLP. Type 1 restorations leaked more than type 2 and 3 cavities for FUJ, VIT and GLP.

Analysis of Variance↗
PubMed1996

Effects of acidic conditioners on dentine demineralization and dimension of hybrid layers.

OBJECTIVES: This study was aimed at investigating the relationships between dentine conditioning for different durations with different acids and (1) the resulting depth of dentinal demineralization and (2) the rebounding capacity of collapsed collagen due to primer and adhesive resin penetration. METHODS: Two commercial and four experimental acids were tested directly by light microscopic evaluation of the depth of decalcification of dentine, and indirectly by determination of the hybrid layer thickness and the total depth of demineralization effects on perpendicular sections through Gluma bonded composite resin specimens. RESULTS: Depths of demineralization increased by both acid concentrations and conditioning times following a logarithmic relationship. There was good agreement between the results of the direct and the indirect procedures. Thirty seconds' conditioning with 20% phosphoric-acid gel resulted in 10-microns hybrid layer thickness. This 20% compound was considered a suitable compromise as a uni-etch conditioner since 30-s etch duration also generated an effective enamel retentive pattern and at the same time a frosted enamel appearance for visual control of extent and efficacy of enamel conditioning.

Acid Etching, Dental↗
PubMed1996

Resin-modified glass ionomer cements: bonding to enamel and dentin.

OBJECTIVES: This study was designed to investigate the effect of storage in water on bonding efficacy to enamel and dentin of four resin-modified (Dyract, De Trey Dentsply; Fuji II LC, GC Dental Corp.; Photac Fil, ESPE; Vitremer, 3M Dental Products), one conventional glass ionomer filling material (Ketac Fil, ESPE) and a resin composite system (Pekafill/Gluma bonding system, Bayer). The hypothesis was that water storage would lead to an adverse effect on bond strength of resin-modified glass ionomer cements to enamel and dentin. METHODS: The shear bond strength of each material was determined after storage periods of 24 h, 1 wk, 1 mon, 3 mon and 6 mon. The data were subjected to one-way ANOVA. Significant differences were determined by multiple comparison testing (significance level 5%). The failure modes of the debonded specimens were analyzed with a dissecting microscope. RESULTS: Shear bond strengths to enamel for Dyract, Photac Fil and Pekafill were 5.2 +/- 1.3, 9.9 +/- 1.6 and 17.0 +/- 2.3 MPa, irrespective of storage time (p > 0.05). For Ketac Fil, the average shear bond strength between 1 wk and 6 mon was 4.5 +/- 1.7 MPa, the mean value for Fuji II LC between 24 h and 3 mon was 10.3 +/- 3.9 MPa and after 6 mon was 19.8 +/- 4.4 MPa, while Vitremer showed increasing shear bond strengths between 24 h (2.4 +/- 0.8 MPa) and 1,3 and 6 mon (13.8 +/- 4.3 MPa). Shear bond strengths to dentin were not adversely affected by storage throughout the 6 mon for Dyract (13.0 +/- 2.6 MPa), Fuji II LC (12.7 +/- 1.7 MPa) and Pekafill (14.6 +/- 3.1 MPa), when tested by ANOVA (p > 0.05). Ketac Fil showed 4.9 +/- 1.2 MPa between 1 wk and 6 mon and lower shear bond strength after 24 h. The average shear bond strengths up to 1 mon for Vitremer were 5.4 +/- 2.5 MPa (p > 0.05). However, at 3 and 6 mon immersion in water, three specimens had loosened spontaneously. With Photac Fil, no adhesion to dentin was registered. Most samples showed cohesive failure patterns in the restorative materials. Adhesive or mixed failures were registered only for Vitremer on dentin and enamel up to 1 wk and for Dyract on enamel. SIGNIFICANCE: Long-term water storage generally had no adverse effect on bonding efficacy of resin-modified glass ionomer cements to dentin and enamel.

Acid Etching, Dental↗
PubMed1996

Monomers with low oxygen inhibition as enamel/dentin adhesives.

OBJECTIVES: This study was conducted to investigate the depths of polymerization inhibition by oxygen, the shear bond strengths to enamel and dentin, and the marginal adaptation in dentin cavities of experimental adhesives containing BisGMA/HEMA of mixtures of low-inhibition BisGMA-dicarbonate with HEMA or with HEMA-carbonate at ratios of 100/0, 80/20, 60/40, 50/50, and 40/60 by weight. METHODS: The inhibition layer thickness was determined microscopically as non-polymerized surface film thickness on three samples each. For bond strength testing, composite cylinders were bonded to enamel and dentin following H3PO4 conditioning with the adhesives dissolved in acetone; marginal adaptation was evaluated in cylindrical dentin cavities. Five specimens each were stored in water for 24 h prior to testing. Shear bond strength results were compared by ANOVA and Duncan's test (p < 0.05), the maximum gap widths by Kruskal-Wallis, ANOVA and Wilcoxon's two-sample test (p < 0.01). RESULTS: Inhibition layer thickness was significantly smaller for modified than for conventional BisGMA/HEMA monomers and increased significantly with HEMA content. In the BisGMA-dicarbonate/HEMA-carbonate group, the inhibited layer was thinner than 1 micron. Apart from the 40 and 50% BisGMA-dicarbonate/HEMA-carbonate mixtures, enamel bond strengths were not significantly different. The highest bond strengths to dentin were 15 and 12 MPa at 50 BisGMA and 50 BisGMA-dicarbonates/HEMA, respectively. The average bond strength for the BisGMA-dicarbonate/HEMA-carbonate group was 5 MPa. Adhesives with 40 and 60% HEMA in the conventional and 40 to 60% HEMA in the dicarbonate/HEMA group showed significantly better marginal adaptation than all others (p < 0.05). SIGNIFICANCE: Carbonate-modified low-inhibition monomers have no advantage as enamel/dentin adhesives compared with conventional BisGMA/HEMA-based resins.

Analysis of Variance↗
PubMed1996

Long-term mechanical characteristics of resin-modified glass ionomer restorative materials.

OBJECTIVES: The purpose of this study was to compare the effects of long-term water storage on the mechanical characteristics of four resin-modified glass ionomer restorative materials with those of a conventional glass ionomer cement and a resin composite material. METHODS: Cylindrical specimens were prepared and stored in water for 1 h, 24 h, 1 wk, 1 mon, 3 mon and 6 mon prior to determination of diametral tensile strength (DTS) and depth of surface indentation both under 1 N load and after removal of the load. RESULTS: Diametral tensile strength was lowest for the conventional glass ionomer cement and highest for the composite; the resin-modified glass ionomer cements were intermediate between the reference materials. Water storage reduced DTS between 24 h and 1 wk or 1 mon but then remained unaffected until the final measurements after 6 mon. The materials showed a trend toward a slight increase in the depth of indentation both under load and after removal of the load with increasing storage time. These mechanical properties indicate the position of four resin-modified glass ionomer cements on a continuum with conventional glass ionomer cement and resin composite as the end points. SIGNIFICANCE: The mechanical properties of resin-modified glass ionomers show that this group of materials is weaker than resin composite but stronger than conventional glass ionomer cement. Water storage for 6 mon has little adverse effect on the mechanical properties.

Analysis of Variance↗
PubMed1996

Bond strength of Gluma CPS using the moist dentin bonding technique.

PURPOSE: To investigate the effects of acetone or water based Gluma primers on bonding efficacy when applied to acid-etched wet, dry or rewetted dentin. MATERIALS AND METHODS: Shear bond strength (SBS, 24 hours) was measured on human dentin etched with 20% phosphoric acid gel and rinsed with water in the wet (blot dried), the conventional (2 seconds air blast), the dry (10 seconds air drying), and the rewetted stage (10 seconds air drying, remoistening and blot drying). The priming solution was either the original water based or an acetone based experimental Gluma primer. Cavity sealing performance and depth of resin impregnation were determined by solvent and by technique along the margins of 4.5 mm wide cylindrical dentin cavities with 90 degree cavosurface angle. RESULTS: The SBSs of the wet technique groups were approximately 18 MPa, irrespective of the primer solvent. Conventional drying gave an SBS almost as high (16.5 MPa). Rewetting was highly effective with acetone as the primer solvent. The dry techniques resulted in moderate (water) and poor (acetone) bond strengths. The cavity margins of acetone based primer treated specimens were consistently gap free with the wet technique. The other seven groups showed between two and six gaps in each group of six specimens. The resin impregnated layer (RIL) thicknesses were 12.5 microns approximately in the wet groups, and thus identical with the total depth of demineralization resulting from the 30-second etching. The alternative techniques showed significantly thinner RILs particularly in the dry groups (7.5 microns).

Acetone↗