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

Abstract

ObjectivesTo 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 MethodsTwenty 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.ResultsComparatively large standard deviations of the mean EDTA reference and albumin soaked samples permeability values reflected the differences of the dentin substrates. The mean chemiluminescence values of specimen treated with GDL and GDG, respectively, were significantly reduced after topical application of the desensitizing agents on albumin-soaked dentin. The effects of GDL and GDG on permeability were not significantly different. Treated specimens showed no surface remnants after rinsing.ConclusionsThe experimental desensitizer gel formulation reduced dentin permeability as effectively as the original Gluma® Desensitizer solution.

Transdentinal cytotoxicity of glutaraldehyde on odontoblast-like cells

“…Even in this unfavorable condition, the treatment of etched dentin for 60 s with 2.5% and 5% GA solutions did not provoke any toxic effects on odontoblast-like cells, while 10% GA showed a significant reduction of cell viability (29.3%). Since the dentin discs were kept hydrated by the culture medium (DMEM), during GA diffusion through the demineralized dentin and dentinal tubules, some of the glutaraldehyde was probably consumed by reacting with the exposed collagen as it diffused down at dentin tubules 14,28,29 and other available proteins 30 and diluted by the fluid inside the tubules. Residues of the unreacted cross-linking agent are a potential source of cytotoxicity of a chemically cross-linked material.…”

“…When GA comes in contact with plasma proteins in dentinal fluid it causes their precipitation blocking exposed dentin tubules and reducing dentin permeability. 30 Based on that principle, GA-containing dental materials, such as GLUMA, were developed to treat dentin hypersensitivity. This dental product, which contains 35mass% 2-hydroxyhethylmethacrylate (HEMA) in its composition, interacts with tooth structure in different ways.…”

“…This dental product, which contains 35mass% 2-hydroxyhethylmethacrylate (HEMA) in its composition, interacts with tooth structure in different ways. 12 While GA clogs proteins within the dentinal tubules, 30 HEMA reacts with the precipitated proteins to form a mixture of polyHEMA and glutaraldehyde-cross-linked protein. 16 However, in spite of beneficial results regarding dentin desensitizing, Gluma has been reported as toxic to different cell lines.…”

A photochemical method for in vitro evaluation of fluid flow in human dentine

“…We developed a new measuring system to determine dentine permeability 10,11 and used it to investigate the time needed to transfer a liquid through the patent tubules of human dentine specimens.…”

“…10,11 Two cylindrical acrylic chambers were sealed with O-rings on each sliced surface of the specimen and clamped in a metal frame connected with the ring. The chamber on the occlusal side of the sliced surface was sealed with a glass cover slip and filled with a chemical illuminant reagent (aqueous solution of 0.02% luminal [5-amino-2, 3-dihydro-1, 4-phtalazinedione] and 1% sodium hydroxide).…”