Growth patterns of Candida albicans in relation to radicular dentin

WOS: A1997XK78200018PubMed ID: 9247954Candida albicans is the most common fungal pathogen isolated from the oral cavity. The role of this organism as an endodontic pathogen is poorly understood. Objectives. The aim of this study was to observe the interaction of C. albicans with root canal walls and the growth patterns of this microorganism in relation to radicular dentin. Study design. Fifteen root sections were infected with C. albicans grown in calf serum and incubated for various periods. The sections were fixed in glutaraldehyde, split into two halves, and evaluated by scanning electron microscopy. Results, Blastospores and hyphal structures were observed on the root canal walls of all specimens. Filamentous hyphal form was dominant in 5-day specimens. Most of the hyphae and blastospores showed penetration into dentinal tubules. The body of germinating mother cells and hyphae demonstrated collapsed cell walls as a result of vacuole formation. Conclusions. With this invasive affinity to dentinal structures, C. albicans may be considered a dentinophilic microorganism

Colonization of Candida albicans on cleaned human dental hard tissues

WOS: A1997XV72100007PubMed ID: 9296271Candida albicans is a fungus that commonly infects oral mucosal surfaces. Limited data exist on biofilm formation by C. albicans on dental surfaces. Human premolar teeth were infected with C. albicans for 10 days and hard-tissue surfaces were examined with a scanning electron microscope. Enamel, cementum and dentine, in the absence or presence of a smear layer, were readily colonized by this micro-organism. Hyphae penetrated into cracks, followed the ridges of the cavities and migrated into dentinal tubules. Blastospores and hyphae were embedded in an extracellular material. These findings suggest that dental hard tissues may be invaded by C. albicans and thus can potentially present a reservoir for disseminating candidal infections. (C) 1997 Elsevier Science Ltd

Morphologic effects on L929 fibroblasts of titanium tetrafluoride application

WOS: 000075888200016PubMed ID: 9768426Objective. The aim of this study was to investigate the effect of titanium tetrafluoride solution on L929 fibroblasts by scanning electron microscopy. Titanium tetrafluoride was then compared with sodium fluoride and acidulated phosphate fluoride. Study design. Cells were treated with fluoride solutions for 1 minute either directly, through a filter membrane with a pore size of 0.4-mu m, or indirectly, through dentin disks; they were then investigated at an electron microscopic level. Results. Fluoride application on smeared dentin disks showed fewer cytotoxic effects on fibroblasts than application on nonsmeared dentin disks. Acidulated phosphate fluoride and titanium tetrafluoride appeared to be more cytotoxic than sodium fluoride. Because all fluoride solutions used in this study contained the same fluoride concentration, pH was considered to be the main factor causing the higher toxicity. Conclusion. Because these solutions demonstrated toxicity in vitro, they must be further evaluated under in vivo conditions to ascertain their clinical safety

Permeability changes of dentine treated with titanium tetrafluoride

WOS: 000082369600009PubMed ID: 10507210Objectives: The aim of this research was to evaluate the effect of titanium tetrafluoride on dentine permeability in comparison with sodium fluoride and acidulated phosphate fluoride to determine their contribution to acid resistance of dentine. Methods: Thirty-two dentine discs were prepared from extracted mandibular molars. The hydraulic conductance of all discs was measured before and after the formation of smear layer. The discs were then randomly divided into five experimental and one-control groups. Coronal surfaces of dentine discs were treated with either fluoride solutions of NaF, APF, 1% TiF4, 0.5% TiF4 and 0.1% TiF4 or de-ionised water. Following the measurement of hydraulic conductance, treated surfaces were subjected to 25% citric acid application. Then, final permeability measurements were made. The data were statistically analysed using ANOVA and Tukey's HSD multiple comparisons. Results: While smear layer formation considerably reduced dentinal permeability of dentine discs, fluoride or de-ionised water application to smeared surfaces did not cause any significant change in hydraulic conductance (p > 0.05). After citric acid application, control and NaF groups showed higher permeability values than 1%, 0.5% and 0.1% TiF4 and APF groups (p < 0.01). Conclusion: Clinical use of acidic solutions of titanium tetrafluoride in dentine cavities may be considered since smeared dentine surfaces an modified to a stabile and acid-resistant state. (C) 1999 Elsevier Science Ltd. All rights reserved

A comparative scalability study of different retrofitting materials

WOS: A1993LK76200006PubMed ID: 8225643The purpose of this study was to compare the sealing ability of high-copper amalgam, glass ionomer cement, and silver glass ionomer cement as retrofilling materials when used with and without varnish. Seventy extracted human single-rooted anterior teeth were instrumented and the root canals obturated with laterally condensed gutta-percha and sealer. The apical 3 mm of each root was resected and a 2 mm-deep apical Class I preparation cut. The roots were then randomly allocated to six groups of 10 teeth and retrofilled with one of the experiment materials. Group I comprised high-copper amalgam, group 2, high-copper amalgam with cavity varnish; group 3, glass ionomer cement without varnish; group 4, glass ionomer cement with varnish: group 5, silver glass ionomer cement without varnish; and group 6, silver glass ionomer cement with varnish. Two groups of five roots each were used as positive and negative controls. The root surfaces were coated with nail polish and specimens immersed in 2% methylene blue solution for 14 days. After vertical sectioning, dye penetration was examined under a stereomicroscope. The results of the study were analysed statistically. The sealing ability of the conventional glass ionomer cement with varnish was significantly better while dye penetration was higher in silver glass ionomer cement without varnish group than the other groups (P<0.01)