Biomedical subjects

Werner J Finger

Publications and source records attributed to Werner J Finger.

11 recordsLinked to original sources

PubMed2007

Effect of a desensitizing agent containing glutaraldehyde and HEMA on bond strength to Er:YAG laser-irradiated dentine.

OBJECTIVES: The aim of this study was to investigate whether a desensitizing agent (GLUMA Desensitizer) containing glutaraldehyde and HEMA improved the bond strength and bonding durability of a self-etching primer adhesive to Er:YAG-irradiated dentine. METHOD: Dentine of 120 human molars was exposed by wet grinding on SiC paper for bond strength testing. Thirty specimens each were allocated to the following treatment groups: (1) control; (2) Er:YAG laser irradiation; (3) Er:YAG laser irradiation followed by application of GLUMA Desensitizer; (4) Er:YAG laser irradiation followed by application of GLUMA Desensitizer and 10s rinsing with water. Composite cylinders were bonded to the dentine surfaces with a self-etching priming adhesive system. Tensile bond strengths (TBS) of 10 specimens of each treatment group were measured after 24-h water storage, 6 months water storage and 12 months water storage, respectively, and the failure modes were analyzed. TBS data were statistically treated by two-way ANOVA and Fisher's PLSD test at a significance level of p<0.05. RESULTS: TBSs for the GLUMA-non rinse and GLUMA-rinse groups were significantly higher than for the laser group at 24 h and 12 months. Specimens from the Er:YAG-irradiated dentine group had significantly lower bond strengths than the control group at each storage time. All control specimens showed cohesive fractures in resin close to the bonding interface whereas the Er:YAG laser-irradiated groups showed both dentine cohesive, resin cohesive and dentine-resin mixed failures. CONCLUSION: Application of GLUMA Desensitizer to Er:YAG-irradiated dentine increases the bond strength and durability of the self-etching priming adhesive used.

Composite Resins↗

PubMed2006

Dimensional accuracy of a new polyether impression material.

OBJECTIVES: The purpose of this study was to evaluate the dimensional accuracy of stone dies produced from standardized impressions with 1 new and 1 conventional polyether impression material and a polyvinyl siloxane reference material. METHODS AND MATERIALS: Impressions with the polyether materials P2 and Impregum and with the polyvinyl siloxane Flexitime were produced at 23 degrees C or 37 degrees C from a truncated steel cone in cylindrical steel trays giving 4-mm impression layer thickness at the prominence line. Stone dies were poured after 1 or 24 hours of storage at ambient atmosphere. Additional impressions were stored at different relative humidity levels (0%, 33%, 50%, 75%, or 100%) for 24 hours prior to die pouring. The accuracy of the stone dies was determined as axial discrepancy between a steel ring, which fit perfectly on the steel die and the occlusal die surface. The base-diameter deviation (deltad) was calculated. RESULTS: After 1 hour, a similar increase in deltad was noticed for impression materials when dies were poured at impression temperature. Impressions made at 37 degrees C exhibited significantly higher deltad than at 23 degrees C. Light-bodied P2 showed the highest deltad increase when dies were poured after 24 hours. Flexitime showed moderate deltad differences at the 2 pouring times. The deltad of dies made from polyether materials decreased significantly with increasing humidity, whereas polyvinyl siloxane was not adversely affected. CONCLUSION: The dimensional accuracy of P2 is comparable to that of the conventional polyether impression material after short-term storage. Polyethers may absorb water, significantly compromising die accuracy upon storage at high humidity.

Absorption↗

PubMed2006

Relationship between degree of polymerization and enamel bonding strength with self-etching adhesives.

PURPOSE: To investigate the relationship between the degree of conversion of double bonds of all-in-one adhesives and their shear bond strength on ground human enamel. MATERIALS AND METHODS: Six commercially available systems and one experimental adhesive were tested: Absolute (ABS; Dentsply-Sankin), Clearfil S3 Bond (CSB; Kuraray), G-Bond (GBO; GC), Hybrid Bond (HYB; Sun Medical), iBond (IBO; Heraeus Kulzer), Xeno IV (XEN; Dentsply Caulk), and experimental iBond NG (ING; Heraeus Kulzer). Conventional shear bond strengths (SBS, n=8) of adhesive-coated enamel specimens bonded to Venus composite (Heraeus Kulzer) and degrees of conversion (DC) (FTIR, n=5) were determined after 1 and 10 min, 1, 2, and 24 h of storage. Data were statistically analyzed using ANOVA and Duncan's post hoc test (0 < 0.05). RESULTS: The adhesives' SBS (MPa) and DC (%) by testing time followed logarithmic regression lines established by the least square method. Mean shear bond strengths after 1 min/24 h were: ABS 9.8/14.9; CSB 14.7/23.4; GBO 14.8/22.0; HYB 9.7/17.0; IBO 11.3/22.3; XEN 9.1/17.3; ING 9.7/25.6. The corresponding mean DC values were: ABS 51.3/66.2; CSB 83.1/90.8; GBO 75.8/87.7; HYB 49.6/67.2; IBO 72.6/93.7; XEN 61.6/74.1; ING 64.9/89.1. Linear regressions for the relationship DC vs. SBS were significant with coefficients of determination (r2) between 0.72 and 0.97. CONCLUSION: Despite similar acidity, the adhesives showed different SBSs on enamel. Based on the relationships between DC and SBS, the cohesive failure patterns observed, and the composition-property relations discussed, it is concluded that the percentage DC is the main parameter influencing an adhesive's bonding efficacy to ground enamel.

Analysis of Variance↗

PubMed2006

Compatibility between an all-in-one self-etching adhesive and a dual-cured resin luting cement.

PURPOSE: To determine if bonding incompatibility between a single-step self-etching adhesive and a dual-cured luting cement is prevented by addition of deprotonizing anion exchange resin powder to the amine component of the resin cement. MATERIALS AND METHODS: iBond adhesive (IBO) (Heraeus Kulzer) and the dual-cured resin cement Twinlook (TWI) (Heraeus Kulzer) were used with base pastes, containing 0, 1, 2, and 4 wt% anion exchange resin (AER) in OH- form. Conventional shear bond strength (SBS) was determined on human dentin. After application of IBO, a cylindrical mold was clamped on the treated surface and bulk filled with TWI. SBS was measured after 24 h in 37degrees C water at a crosshead speed of 1 mm/min. The following curing protocols were investigated: Group 1: IBO not light cured, TWI redox cured; group 2: IBO light cured, TWI redox-cured; group 3: IBO light cured, TWI dual cured (n=8). The data were statistically analyzed using ANOVA and Duncan's post-hoc test at alpha < 0.05. RESULTS: The mean SBSs (MPa) with original TWI in groups 1, 2, and 3 were 12.7aA, 16.4bA, and 24.7cA. The corresponding figures for 1% AER were: 16.6aB, 23.0bB, 22.8bA; for 2% AER: 16.8aB, 22.6abB, 24.6bA; and for 4% AER: 16.2aAB, 22.5bB, 24.7bA. Different small and capital letters denote significant differences by treatment group and by AER content, respectively. CONCLUSION: Addition of anion exchange resin to the amine component of the dual-cured resin cement enhances the bond strength to dentin upon redox curing by prevention of amine neutralization through functional acid monomers from an all-in-one adhesive, mainly when the adhesive or the luting cement were not light cured.

Analysis of Variance↗

PubMed2005

Compatibility between self-etching adhesive and self-curing resin by addition of anion exchange resin.

OBJECTIVE: The aim was to investigate whether anion exchange resin powder in the OH(-) form, added to the amine component of self-cured resin can deprotonize acid groups of a self-etching adhesive and thus eliminate incompatibility caused by amine neutralization. METHODS: Shear bond strength (SBS) of a self-cured CorePaste (COP), bonded either with all-in-one adhesive iBond (IBO) or with IBO coated with a self-cured experimental resin (SCR), loaded with 0, 8, 16, or 32 wt% of anion exchange resin powder (AER) in OH- form, were determined on 80 enamel and dentin surfaces each after 24 h water storage. IBO specimens were either light-activated or not. Flexural modulus and strength of the four SCR resins were determined by three-point bending. Data was analyzed by one-way ANOVA and Duncan's post hoc test (p<0.05). RESULTS: Enamel SBSs of COP on IBO were 20-25 MPa, in combination with SCR (0 up to 32%) >25 MPa for activated or non-activated IBO. COP on IBO produced no bond on dentin, with the non-loaded SCR 5-10 MPa SBS was achieved, and 15 and 21 MPa were measured with the three AER-loaded SCRs on activated and non-activated IBO, respectively. Flexural moduli of SCR with 0 and 8% AER were higher than with 16 and 32%. Flexural strengths were not significantly different. SIGNIFICANCE: Addition of anion exchange resin to the amine component of self-cured resin is an effective means of enhancing the bond strength on dentin and to prevent amine neutralization through the acid groups of self-etching primer adhesives.

Acid Etching, Dental↗

PubMed2005

Effect of application mode on bonding performance of self-etching adhesives.

PURPOSE: To investigate effects of static vs. dynamic application of self-etching adhesives on bond strengths to enamel and dentin and marginal adaptation in dentin cavities. METHODS: Products: AC Bond experimental (ACB), AQ Bond (AQB), Fluorobond (FLB), and One-Up Bond F (OUB). Shear bond strengths (SBS) to enamel and dentin were determined on human molars. Primer applications: 1. undisturbed, 2. brush agitation, 3. ultrasonic agitation (Cavitron, lowest setting), or 4. ultrasonic agitation (5 seconds). A 3.5 x 2 mm mold was mounted for application of the resin-based composite Charisma. Six specimens for each condition were stored for 24 hours and loaded until failure. STATISTICS: ANOVA and Scheffé test (P= 0.05). Marginal adaptation was determined in cylindrical dentin cavities (4 x 1.5 mm) 15 minutes after curing of Charisma. Eight specimens/adhesive were produced following application modes 1, 2, and 4. Kruskal-Wallis and Mann-Whitney showed a P= 0.05. RESULTS: Application modes showed no differences in shear bond strengths (SBS) on enamel and dentin by adhesive. SBSs on enamel were not different from those on dentin. Average SBSs for ACB, AQB, FLB, and OUB were 21.0, 21.9, 20.8, and 13.7 MPa. Ranking of adhesives for SBS on enamel and dentin was: AQB, ACB > ACB, FLB > OUB. Application modes had no influence on marginal adaptation. From the 24 cavities each, all ACB, 21 AQB, 13 FLB, and 1 OUB were gap-free. Mann-Whitney ranking: ACB, AQB, FLB > OUB.

Acid Etching, Dental↗

PubMed2005

Evaluation of the elastic recovery of polyether impression materials.

PURPOSE: To evaluate and compare the effects of induced strain, time of straining, and loading time on the elastic recovery of two polyether impression materials and a vinyl polysiloxane reference material. METHODS: Specimens of the light and heavy-bodied types of the polyether materials P2 (P2L/H) and Impregum (IML/H) and of the vinyl polysiloxane impression material Flexitime (FLC/H) were loaded in a cone-plate rheometer with tensile strains between 16.4 and 60%, at different times after mixing, and at loading times between 1 and 10 seconds. The resulting permanent deformation was determined from creep curves. For each material and each variable condition six specimens were tested at ambient laboratory atmosphere. Regression analyses and ANOVA were used for statistical data analysis. RESULTS: Both induced strain, time of straining, and straining rate were significantly associated with the resulting permanent deformation of all materials, except FLC when loaded in the well-set stage between 1 and 10 seconds loading time at 37.4% induced tensile strain (P< 0.001). Apart from P2 the heavy-bodied impression materials showed significantly higher secondary creep (P < 0.05) than their corresponding light-bodied versions.

Dental Impression Materials↗

PubMed2002

Direct and indirect fiber-reinforced fixed partial dentures: case reports.

Direct and indirect fiber-reinforced resin composite fixed partial dentures are a new way to produce minimally invasive, esthetic, and cost-effective metal-free tooth replacements. These treatment alternatives have a number of indications, for example, chairside tooth replacements, long-term provisional fixed partial dentures, economically feasible tooth replacements for patients who cannot afford more traditional treatment regimens, and tooth replacements for medically compromised patients who are unable to withstand the physical stress associated with fabrication of traditional fixed prostheses. This article presents four typical cases in which fiber-reinforced fixed partial dentures seemed to be the preferable treatment modality.

Acid Etching, Dental↗

PubMed2002

Radiopacity of fiber-reinforced resin posts.

PURPOSES: (1) To determine the radiopacity of one titanium and seven fiber-reinforced resin posts by densitometric analyses of radiographs, taken from the separate posts and from posts after seating in extracted root-treated human canine teeth with and without a radiopaque luting resin, respectively, and (2) To receive a ranking order by 20 dental practitioners of 16 randomly selected radiographs (2 for each post brand) by radiodensity and by acceptability assessment of the posts' radiographic appearance. MATERIALS AND METHODS: One reference titanium post (1) and the following 7 commercial fiber post brands were investigated: AEsthetiPlus/RTD (2), FiberKor/Jeneric Pentron (3), Light-Post/RTD (4), LightPost/Dentatus (5), Mirafit/Hager & Werken (6), Snowlight/Carbotech (7), and Snowpost/Carbotech (8). Standardized radiographs of the separate posts and of posts in extracted canines both before cementation and after cementation with Panavia 21 EX were produced and evaluated densitometrically together with a reference aluminum step-wedge. The cemented posts' radiodensities were determined from radiographs taken without and with 10 mm Plexiglass shielding. The optical densities were recorded in mm Al equivalents. Sixteen radiographs (2 for each post) were presented in random order to 20 dentists for ranking by decreasing radiopacity and by clinical acceptability scores from good (1), adequate (2), acceptable (3), not acceptable (4), to no radiopacity (5) of the posts' radiographic appearance. Statistical evaluation by ANOVA and Duncan post-hoc test at P< 0.05. RESULTS: Statistically the posts' radiodensities were significantly different. For separate and cemented posts, recorded from radiographs of Plexiglass shielded specimens, respectively, the following Duncan rankings were obtained: 1>7, 8>3>2, 4, 5>6 and 1>7, 8> 3, 5, 2, 6>6, 4. The dentist ranking by radiopacity scores was 1>7, 8>3>5,6>4>2, and by clinical acceptability scores 1>7, 8>3>2, 4, 5, 6. The titanium post (1) and posts 7 and 8 received scores better than acceptable, post 3 was assessed acceptable, whereas posts 2, 4, 5 and 6 were characterized as "not acceptable" or "not radiopaque".

Absorptiometry, Photon↗

PubMed2002

Clinical evaluation of the role of glutardialdehyde in a one-bottle adhesive.

PURPOSE: To evaluate clinically whether the addition of glutardialdehyde to the one-bottle enamel-dentin adhesive Gluma Comfort Bond (GCB) has a desensitizing function, as insinuated by the brand name Gluma Comfort Bond+Desensitizer (GCB+D). MATERIALS AND METHODS: Two pain studies following identical protocols were conducted in Abu Dhabi (A) and Bologna (B). Each of the 60 and 59 patients selected, respectively, had two sensitive cervical tooth sites, characterized by a score three or higher on a five-step pain scale: 1 (no), 2 (slight), 3 (mild), 4 (severe), 5 (very severe) discomfort upon application of a 2-second cold air stimulus. The buccal sensitive sites treated in A were generally small, in B larger and in most cases extending into the proximal tooth area. The patients indicated their discomfort level according to the pain scale prior to and immediately after topical application of GCB and GCB+D, respectively, and then at recalls after 1 week, 1 (A) or 3 (B) months, and 6 months. The data was statistically analyzed by chi2-tests (P < 0.05). RESULTS: With the cumulative scores 1 and 2, the following percentage success rates were found for GCB/GCB+D. A: postoperatively 93/98, 1 week and 1 month 98/98, and at 6 months 92/100. In B, the respective decrease in sensitivity was uniformly 43/100 throughout the entire evaluation period, postoperatively through 6 months. The 33 teeth (57%) of GCB with scores 3 and 4 in the B-study received a rescue treatment with Gluma Desensitizer immediately after the 1 week recall. This regimen reduced the sensitivity instantaneously to scores 1 and 2 until the end of the evaluation after 6 months. In the A-study, GCB+D was significantly more effective than GCB after 1 week, 1 month, and 6 months, in the B-study at all recall sessions. It is hypothesized that a thin film of adhesive applied to a sensitive area may not polymerize and seal the dentin surface adequately due to oxygen inhibition. In particular, proximal sensitive tooth sites with poor access for adhesive application are suspected to remain inadequately sealed with a polymer film and thus sensitive. In this latter case however, glutardialdehyde as a component of the adhesive compound will result in coagulation of peripheral tubular liquid protein and thus desensitization, due to hampering of the liquid shift across the tubules upon excitation of a cold stimulus. In conclusion, glutardialdehyde played an active and effective role as a desensitizing agent, when added to the ethanol-water based one-bottle adhesive Gluma Comfort Bond.

Adult↗

PubMed2002

Effect of smear layer thickness on bond strength mediated by three all-in-one self-etching priming adhesives.

PURPOSE: The aim of this study was to investigate the effect of dentin smear-layer thickness on the bond strength of three all-in-one adhesives of different acidity. MATERIALS AND METHODS: Peripheral dentin was prepared by wet grinding on SiC papers (80-, 180-, 240-, 320-, 400-, 600-, 4000-grit), and by turbine cutting with supercoarse, coarse, medium, fine, or extrafine diamond burs. The smear layer thickness (SLT) was measured microscopically. The relationship between SLT and average grain size of the abrasives used to prepare the dentin surface was described by regression analysis. Shear bond strength (SBS) was determined for the following adhesives: AC Bond, pH 2.1 (experimental, Heraeus); AQ Bond, pH 2.5 (Sun Medical); and Prompt L-Pop, pH 1.1 (3M-Espe). Six specimens were tested for each adhesive on dentin ground with each of the seven SiC grit sizes. The mode of failure was inspected by SEM. SBS data were analyzed by one-way ANOVA and Fisher's PLSD test at p < 0.05. RESULTS: A logarithmic relationship between SLT and grain size of the abrasives was established. The coefficient of determination R2 for the regression line was 0.803. Shear bond strengths for the individual adhesives did not differ significantly by SiC grit size. SBS of AC Bond (18.3 MPa) was greater than the SBS of AQ Bond and Prompt L-Pop (16.9 MPa). Cohesive failures were consistently found in resin composite or adhesive. CONCLUSION: Smear layer thickness increased with decreasing SiC grit numbers and increasing diamond bur roughness. In spite of the widely differing acidity, all three adhesives tested were equally effective over the range of SLT from 2.6 microm through 0.9 microm.

Adhesives↗