In vitro dentin permeability after application of Gluma® desensitizer as aqueous solution or aqueous fumed silica dispersion

OBJECTIVES: To assess and to compare the effects of Gluma® Desensitizer (GDL) with an experimental glutaraldehyde and HEMA containing fumed silica dispersion (GDG) on dentin permeability using a chemiluminous tracer penetration test. MATERIAL AND METHODS: Twenty disc-shaped dentin specimens were dissected from extracted human third molars. The dentin specimens were mounted in a split chamber device for determination of permeability under liquid pressure using a photochemical method. Ten specimens were randomly selected and allocated to the evaluation groups Gluma® Desensitizer as aqueous solution and glutaraldehyde/HEMA as fumed silica dispersion, respectively. Dentin disc permeability was determined at two pressure levels after removal of smear with EDTA, after albumin soaking, and after application of the desensitizing agents. Two desensitizer-treated and rinsed specimens of each group were examined by scanning electron microscopy (SEM) for surface remnants. RESULTS: Comparatively large standard deviations of the mean EDTA reference and albumin soaked samples permeability values refected the differences of the dentin substrates. The mean chemiluminescence values of specimen treated with GDL and GDG, respectively, were signifcantly reduced after topical application of the desensitizing agents on albumin-soaked dentin. The effects of GDL and GDG on permeability were not signifcantly different. Treated specimens showed no surface remnants after rinsing. CONCLUSIONS: The experimental desensitizer gel formulation reduced dentin permeability as effectively as the original Gluma® Desensitizer solution

Effect of two desensitizing agents on dentin permeability in vitro

Objective The aim of this in vitro study was to investigate the effect of two desensitizing agents and water on hydraulic conductance in human dentin. Material and Methods GLUMA Desensitizer PowerGel (GLU) contains glutaraldehyde (GA) and 2-hydroxyethyl methacrylate (HEMA), and Teethmate Desensitizer (TD) is a powder comprising tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) that is mixed with water. Deionized water was used as a negative control (CTR). Thirty discs with a thickness of 1.2 mm were cut from the coronal dentin of the third molars and cleaned with 0.5 M EDTA (pH 7.4). After being mounted in a split-chamber device, the discs were pressurized with water at 1 kPa and 3 kPa in order to measure flow rates with a highly sensitive micro-flow sensor and to calculate hydraulic conductance as a baseline value (BL). Following the application of GLU, TD, and CTR (n=10), hydraulic conductance was remeasured with intermittent storage in water after 15 min, 1 d, 1 w, and 1 m. Reduction in permeability (PR%) was calculated from hydraulic conductance. Data were statistically analyzed using nonparametric methods (

Effects of glutaraldehyde, HEMA, and Gluma Desensitizer on in vitro dentin permeability

Objective: Aim of this in vitro study was to investigate dentin permeability after application of Gluma Desensitizer (Heraeus Kulzer, Hanau, Germany), and aqueous solutions of glutaraldehyde and HEMA, respectively.Method: The permeability of dentin slices, cut from crowns of human third molars, was determined using a split-chamber device. Activator fluid crossing through the dentin disc from the apical side produces a photochemical signal upon contact with the luminol-containing reagent at the opposite side of the specimen. This light signal is proportional to the liquid flow during pressurizing cycles with 2.5 kPa for 2 minutes and with 13 kPa for 1 minute, respectively. Ten specimens each were investigated after EDTA treatment for removal of cutting smear (Baseline), then after soaking in protein solution (Albumin) and finally after application of each of the desensitizer solutions, respectively. Statistical data treatment: non-parametric ANOVA and post-hoc testing (p<0.05).Results: Permeability of all specimens was not significantly different at Baseline and Albumin evaluation stages. Glutaraldehyde and HEMA solutions did not reduce permeability of dentin discs, whereas Gluma Desensitizer showed pronounced permeability reduction. Conclusion: Supposedly, permeability decrease results from a reaction between glutaraldehyde and albumin (protein precipitation) and secondly from induction of HEMA polymerization. &nbsp

How reliable are failure site assessments after "macro" shear debonding of resin from tooth substrate?

Objective: To determine inter-examiner reliability and concordance of failure pattern assessments made by stereomicroscopy and SEM, respectively, after macro shear bond testing of bonded resin composite from human enamel and dentin.Method: Six investigators examined independently the failure pattern morphology of 184 debonded tooth side specimens using stereomicroscopy inspection at 20-fold magnification. The same specimens were investigated using SEM at 1000-fold magnification to determine the "true" failure site morphology. Failures were classified as 1=adhesive, 2=mixed (adhesive-cohesive), 3=cohesive in resin, 4=cohesive in tooth, 5=mixed cohesive (resin-tooth).Results: Spearman’s rho coefficients of correlation between the paired examiner score allocations differed between "strong disagreement" and "moderate agreement". Comparisons of each examiner's ratings with the SEM ratings revealed coefficients, describing these relationships as“disagreement"in the worst and“moderate agreement" in the best case.Conclusion: Inter-examiner reliability in fracture pattern characterization of tooth specimens is ambiguous and not concordant with fracture pattern morphology rating using SEM