Depth Of Dye Penetration Research Articles

Infiltração marginal em cavidades de classe V restauradas com materiais estéticos, utilizando diferentes técnicas restauradoras

The purpose of this study was to compare the microleakage of class V cavities restored with composite resin (CR), resin-modified glass ionomer cement (RMGIC) and polyacid-modified resin composite (PAMRC), using different clinical procedures. Thirty-six noncarious human molars were used in this study. A class V cavity, measuring approximately 3 mm x 4 mm x 2 mm, was prepared in each tooth in both buccal and lingual aspects, with a diamond bur (number 1,093) at high speed, with coolant water spray. The occlusal margin was located on enamel and the gingival margin was located on dentin. The teeth were divided into 9 groups with 8 specimens each. The cavities were restored according to different techniques. The specimens from groups 1, 2, 4 and 5 did not receive acid etching. The samples were stored in water at 37 degrees C for 24 hours, subjected to occlusal load, thermocycled and immersed in rhodamine B. The restorations were then washed and sectioned in buccolingual direction. The depth of dye penetration was scored from zero (no leakage) to 3 (maximum leakage). The Kruskal-Wallis test revealed statistically significant differences between the materials (p < 0.05). PAMRC used without acid etching showed the greatest score of leakage in both margins. In the gingival margin, CR showed scores of leakage lower than those of PAMRC and RMGIC. Additional retentions and acid etching were able to decrease microleakage in PAMRC restorations in both gingival and occlusal margins.

Mineral trioxide aggregate — a new experimental material for retrograde filling

Objective To compare apical microleakage of MTA following reverse retrograde root filling with that following amalgam and EBA retrofilling. Design Prospective random control trial. Setting It was conducted at the University of Jordan in 1998. Materials and methods The root canals of 79 extracted teeth were instrumented and obturated with vertically condensed gutta-percha. Each tooth was apically resected and the apex was prepared ultrasonically to 3 mm depth and the root surface isolated with nail varnish. Teeth were divided randomly into three groups of 25 teeth each. First group was retrofilled with amalgam, second group with EBA and the third group with MTA. Following immersion in 1% methylene blue dye for 72 hours, the roots were sectioned and the depth of dye penetration was evaluated by a stereomicroscope at x10 magnification. Interventions Super EBA is a reinforced zinc oxide cement based on a mixture of 32% eugenol and 68% ethoxy benzoic acid (EBA). MTA is a mineral trioxide aggregate cement (MTA) based on a mixture of sterile water. Main outcome measures The sealing effectiveness of the retrograde filling materials used in this study was determined by their ability to inhibit dye penetration. Results 56% of the group filled with amalgam and 20% of the group filled with EBA showed dye leakage beyond the retrofilling material whereas the MTA group showed none, two samples from MTA group were eliminated because of their fractured roots. The chi-squared test revealed a statistically significant difference among all three groups (P < 0.05). Conclusion MTA cement provides a better seal than amalgam and EBA cement when used as retrograde filling, but the extrapolation of this result into a clinical practice may be questionable.

Multiple Pass Thermal Dye Diffusion Modeling Profiles

A numerical model has been developed to simulate the dye transfer thermal printing process. The simulation incorporates the multiple layers of the head/media interface and uses finite difference techniques to calculate the temperature and mass distributions. Surface boundary conditions have been determined from experimental print head temperature data. This enables us to use different pulse modulation heating schemes. Also, the concentration dependence of diffusivity is taken into account which leads to a non-linear governing equation. The amount of dye transferred and its distribution in the receiving material can be predicted.The model has been extended to incorporate multiple pass printing. Depth profile predictions are made for a variety of input parameters. Various printing line times, pulse modulation schemes, partition coefficients, donor and receiver glass transition temperatures, and receiving layer thickness are used to calculate the dye concentration profile of the receiver. The surface layer concentration and the depth of dye penetration are of particular importance. These predictions are compared to experimental cross-sectional measurements of dye transfer in receiver material.

A new method to improve penetration depth of dyes into the follicular duct: Potential application for laser hair removal

Background: Many persons seek to decrease hair growth and hair density. Although a variety of epilating methods are available, a practical and permanent hair removal treatment is needed. Objective: The purpose of this study was to evaluate a new method of obtaining a better penetration depth of dyes into the follicular duct. By increasing both the quantity and the penetration depth of dye into the follicular duct, the efficacy of laser hair removal could be improved. Methods: Dye penetration depth was assessed histologically after the use of formulations containing rhodamine-6G-loaded microspheres dispersed into two different silicones. Each formulation was tested on two hairless rats. After formulation application, dye diffusion was realized by applying ethanol on the skin to extract rhodamine-6G from microspheres. Results: In all our experimental conditions follicular targeting occurred. No difference in the penetration depth of rhodamine-loaded microspheres was seen between our different silicone formulations. After ethanol application, the penetration of rhodamine-6G into the hair follicle was considerably increased by the fluid silicone vehicle (vs volatile silicone). Conclusion: This new galenical approach aims to transport a dye into the hair follicle specifically and deeply. By using adequate laser, the efficiency of laser hair removal could be increased. (J Am Acad Dermatol 1999;41:172-5.)

Avaliação in vitro da microinfiltração em cavidades de classe V restauradas com diferentes combinações de resina composta e cimento de ionômero de vidro

O propósito deste estudo foi comparar o padrão de microinfiltração em restaurações classe V usando diferentes combinações de cimento ionomérico/resina composta. Cinqüenta cavidades foram preparadas nas superfícies vestibular e lingual de caninos e de pré-molares recém-extraídos. A margem gengival dos preparos estendeu-se até a dentina/cemento, e a margem oclusal localizou-se em esmalte. As cavidades foram restauradas como se segue: cimentos ionoméricos restauradores modificados por componentes resinosos (Fuji II LC e Vitremer); sistema adesivo/resina composta (Scotchbond Multi-Uso/Silux Plus); técnica sanduíche empregando-se o sistema adesivo/resina composta descrito, com um cimento ionomérico forrador (Vitrebond e GC Lining LC). Os espécimes foram armazenados em água destilada, polidos, submetidos à ciclagem térmica e imersos em fucsina. A extensão de penetração do corante foi classificada segundo o critério de escores, e os dados foram analisados estatisticamente, não sendo observadas diferenças significativas tanto entre materiais como entre margens.

The effects of L-arginine and iloprost on the viability of random skin flaps in rats.

The effects of an intravenous infusion of L-arginine as a physiological precursor of endothelium-derived relaxing factor/nitric oxide (EDRF/NO), iloprost (a stable prostacyclin (PGI2) analogue), and L-arginine combined with iloprost on skin viability were studied in 9 x 3 cm random pattern skin flaps in rats. Intravenous infusion of all drugs was started at the beginning of the operation and continued for 60 minutes. At the end of infusion period the depth of fluorescein dye penetration in the skin flap was assessed visually from photographic records, and the flap survival area was measured by the grid method at the seventh postoperative day. There was a significant reduction in distal necrosis of random skin flaps after intravenous infusion of L-arginine, iloprost, and L-arginine combined with iloprost (p < 0.01). Possible mechanisms that may be responsible for impairment of endothelium-dependent vasodilation and vasospasm in the microvasculature of random skin flap and their prevention with L-arginine and iloprost include restoration of the depleted stores of NO which in turn causes vasodilatation and has an antithrombotic effect.

Sealing ability of five different retrograde filling materials

The sealing ability of Amalgam, Harvard-Cement, Diaket, gold-leaf, and Ketac-Endo as retrofilling materials was investigated. Paper cones were fixed with Harvard-Cement in the instrumented roots of 100 extracted human incisors. Apicectomy was performed and a 2-mm-deep retrograde cavity was prepared. Teeth were assigned to five groups (n = 20); each group received a different filling material. Surfaces of the roots were isolated with nail polish. Teeth, were stored in 1% methylene blue dye for 72 h. Roots were sectioned, and the depth of dye penetration was evaluated through a stereomicroscope. Retrofills with Ketac-Endo showed significantly less leakage compared with amalgam. There was no significant difference between the amalgam and Diaket groups. The sealing ability of Harvard-Cement and gold foil was lower than amalgam. It was concluded that retrograde fillings with Ketac-Endo or Diaket can be considered as alternatives for amalgam.

Drug Delivery into the Arterial Wall: A Time-Course Study with Use of a Lipophilic Dye

One potential approach to the prevention of restenosis after angioplasty is to deliver antiproliferative agents directly to the angioplasty site. The purpose of this study was to determine the time course of drug penetration into the media of the balloon-dilated artery. Balloon angioplasty of the left and right iliac arteries was performed once for 1 minute in each of five rabbits. A double-balloon catheter was then positioned at the site of angioplasty, and the fluorescent dye PKH26 (molecular weight, 961) was delivered under pressure to simulate drug delivery. Afterward, the arteries were removed and dye penetration into the media was measured on frozen cross sections by epifluorescence microscopy. Delivery of the dye was performed for periods ranging from 5 to 50 minutes at a mean pressure of 189 mm Hg. The depth of dye penetration (D, micrometers) was directly related to dye perfusion time (T, minutes) (D = 0.348T + 11.958, r = 0.496, P < .01). This equation predicts complete medial dye penetration in 81 minutes assuming an average intima-media thickness (40 microns). This study demonstrates that PKH26 can be delivered to the media of the dilated artery. However, the time required to obtain complete penetration may limit the utility of this double-balloon catheter approach to drug delivery.

An experimental study of the sealing ability of a dentinal apical plug treated with bonding agent

The purpose of this study was to evaluate the sealing ability of a dentinal apical plug treated with a bonding agent. Ninety human lower premolars were used. The teeth were divided into three groups. in groups 1 and 2, to prepare an apical isthmus of 1 mm in length, the first apical seat was prepared with a #45 K file 1 mm short of the anatomical apex and with a #60 K file 2 mm short for the second apical seat. Dry dentin fillings were packed in the apical isthmus with a #60 K file. In group 1, the root canal was obturated with gutta-percha and Canals root canal sealer by the lateral condensation method. In group 2, following an application of the bonding agent to the plug, the root canal was obturated in the same way. In group 3 (control), a single apical seat was prepared with a #60 K file 1 mm short of the apex and the root canal was obturated similarly. The teeth of three groups were immersed in a 1% methylene blue solution for 1, 2, and 4 wk. Dye penetration depth from the apical foramen was determined. Group 2 showed no leakage after 4 wk. Groups 1 and 3 showed dye penetration into the root canal, and in these two groups dye penetration increased with time.

Effect of storage media on microleakage of five dentin bonding agents

The objective of this study was to investigate the effect of different storage media on microleakage at the gingival margin of mixed Class V composite restorations. Human molars were either used immediately after extraction (control group) or after a 3 – 4 wk storage period in 1% chloramine, 70% ethanol, 10% formalin, or 0.1% thymol. Class V cavities with cervical margins in cementum or dentin were prepared and restored with a microfill composite using five different dentin bonding agents. After thermocycing (1440 × from 5°C to 55°C) and basic fuchsin staining, the depth of dye penetration at the gingival margins was determined and ranked on a scale of 0 to 4. Class V restorations in teeth stored in formalin showed significantly less microleakage (mean leakage score, MLS=1.7) than restorations in freshly extracted teeth (control group; MLS=3.1). Microleakage scores in teeth stored in chloramine (MLS=2.7), ethanol MLS=3.0) or thymol (MLS=3.2) were not significantly different from the microleakage scores in the control group. The improvement of in vitro efficacy of dentin bonding agents when using extracted teeth stored in formalin is probably a result of collagen cross-linking by formaldehyde. Since such an alteration of the dentin does not reflect the condition of the substrate in vitro, extracted teeth assigned for in vitro evaluation of dentin bonding agents should not be stored in formalin. In teeth stored in 1% chloramine, the sums of ranks and the rank orders of the dentin bonding agents were comparable to those in freshly extracted teeth. Taking into account the results of previous in vitro investigations, an aqueous 1% chloramine solution is recommended for storage of extracted teeth in the laboratory testing of dentin bonding agents.

Coronal dye penetration of the apical filling materials after post space preparation

Forty canals of palatal and distal roots of molars were cleaned and shaped with the use of a step-back technique. Thirty canals were obturated, 10 each with lateral, vertical, and thermafil techniques. Five root canals were obturated without a root canal sealer and served as positive controls. Another five root canals were obturated, and their coronal half was sealed with sticky wax and served as negative controls. The apical 5 to 6 mm of the filling materials were exposed to india ink for 48 hours. The depth of dye penetration was measured in all groups and statistically analyzed. The apical plugs in the thermafil group had the highest degree of coronal leakage. The ANOVA test showed a significant statistical difference between coronal dye leakage between this group and those found in canals filled by lateral or vertical condensation techniques. The results indicate that the apical filling materials obtained by lateral or vertical condensation leak less than those obtained by thermafil.

Effect of different sealers on thermoplasticized gutta-percha root canal obturations

The objective of this study was to test the hypothesis that the apical seal provided by thermoplasticized root canal obturations depends on the film thickness of the sealer used. The root canals of 120 maxillary cuspid teeth were instrumented and divided into six equal groups of 20 teeth. A thermoplasticized gutta-percha root canal obturator was used to make an impression of the lubricated canal and coated with a sealer cement before reseating. Five different sealer cements of known film thickness were studied. They were, in the decreasing order of film thickness, Roth's Type I Cement, Seal-apex, Lee Endofil, AH26, and Ketac-Cem. The control group that received no sealer was prepared as recommended by the manufacturer. The degree of microleakage was based on the depth of dye penetration from the apical end measured by two independent examiners. The data collected were analyzed by analysis of variance and Weibull distribution. Analysis of variance shows that the control group exhibited significantly higher dye penetration depth (p < 0.05) while there were no significant differences among the other five groups. Analysis by Weibull distribution function shows that Lee Endofil and AH26 exhibited a higher percentage of lower linear dye penetration values compared with other groups.

A comparative in vitro coronal microleakage study of new endodontic restorative materials

Complete sealing of endodontic access openings between appointments and after completion of therapy is an essential element in achieving endodontic success. Recently, two new products for use as temporary restorative materials, TERM and Dentemp, have become available. The purpose of this study was to compare in vitro the sealing ability of Cavit, Cavit-G, Cavit-W, and IRM-Caps, with TERM, Hard-TERM, and Dentemp. Standard access cavities were prepared in 144 intact extracted human teeth. They were equally and randomly distributed into seven groups, and their access openings were temporized. Specimens were submitted to thermocycling (5 to 55 degrees C) for 7 days and stained with silver nitrate. The teeth were split in half, and the greatest depth of dye penetration at the tooth surface was recorded. TERM exhibited the least leakage, while Hard-TERM demonstrated the greatest leakage, at the tooth-restoration interface.

Effect of apical resections and reverse fillings on thermafil root canal obturations

This in vitro dye leakage study examined the influence of apical root resection and reverse amalgam fillings on the apical seal of root canals obturated with Thermafil. Fifty human canine teeth were instrumented and obturated with either laterally condensed gutta-percha or Thermafil using Roth's zinc oxide-eugenol Type I regular sealer. After 24 h, one of the following additional procedures was performed on 30 of the teeth: 2-mm apical resection, 4-mm apical resection, and 2-mm apical resection plus reverse amalgam filling 2 mm in depth and diameter. The external root surfaces were coated with enamel paint and the teeth were exposed to 1% methylene blue dye at 37 degrees C for 2 wk. The roots were split longitudinally and the depth of linear dye penetration was measured through a stereozoom microscope. Statistical analysis showed no significant differences in the linear dye penetration among the various groups of teeth.

Posterior composite Class II restorations: in vitro comparison of preparation designs and restoration techniques

The aim of this study was to evaluate conservative preparation designs for the restoration of Class II lesions with posterior resin composite. Fourteen primary and 14 permanent molars were obtained. Conservative modified MO and DO preparations were placed in half the teeth; conventional MO and DO preparations were placed in the remaining teeth. Randomly, a glass-ionomer liner was placed over the exposed dentin in one preparation of each tooth; a calcium hydroxide liner was placed in the remaining preparations. Posterior resin composite was placed in all teeth, and the teeth were loaded with a 17-kg force. Teeth were thermocycled, stored in 37°C water, then immersed in 50% silver nitrate solution and placed in developer. The teeth were sectioned and photographed. Microleakage was calculated according to the depth of dye penetration, on a 6-degree scale. Results demonstrated the conservative modified restorations and conventional restorations, when glass-ionomer liner was used, to have less marginal microleakage, in both primary and permanent teeth, than their calcium hydroxide counterparts.

The effect of human blood on the sealing ability of root canal sealers: An in vitro study

The effect of human blood and moisture contamination on the sealing ability of six commonly used root canal sealers was studied. The materials tested--Tubliseal, Diaket, AH26, Nogenol, Roth, and Endomethasone sealers--were placed in root canals with laterally condensed gutta-percha. The specimens were immediately immersed in blood or saline solution or kept dry for 2 hours. All the teeth were then subjected to methylene blue dye for 1 hour. A comparison of the seal was made by observation of dye penetration around the filling materials. Under all conditions, Tubliseal exhibited the least amount of marginal penetration, followed by AH 26. There was no significant difference in the depth of dye penetration between Diaket and Tubliseal in dry and wet conditions. Although AH 26, Nogenol, Roth, and Endomethasone sealers showed comparable sealing ability under dry conditions, the sealing ability of AH 26 and Diaket was superior to that of Nogenol, Roth, and Endomethasone sealers in moisture contamination. A significant drop in the seals afforded by AH26, Diaket, Roth, and Endomethasone sealers was recorded when these materials were immersed in blood. On the other hand, immersion in blood caused no significant change in the sealing ability of Nogenol.

A comparison of leakage between silver-glass ionomer cement and amalgam retrofillings

Apical microleakage following reverse filling with zinc-free amalgam was compared with that using silver-glass ionomer cement. The root canals of 20 extracted human maxillary canine teeth were instrumented and obturated with laterally condensed gutta-percha and sealer. Each root was then apically resected at a 45-degree angle to the long axis of the tooth. Following application of nail polish to the root surfaces, standardized apical cavity preparations were made. Ten of the cavity preparations were coated with cavity varnish and filled with zinc-free amalgam; the other 10 preparations were filled with silver-glas ionomer cement. After retrofilling, specimens were suspended in 2% methylene blue dye and placed into an incubator at a temperature of 37°C for 7 days. The teeth were sectioned longitudinally, and the depth of linear dye penetration was measured. Penetration of dye was significantly less (p

Apical leakage associated with retrofilling techniques: A dye study

This in vitro study utilized methylene blue dye to evaluate the extent of apical microleakage following reverse filling procedures. Forty human canine root canals were biomechanically prepared and obturated with laterally condensed gutta-percha and Roth's 801 Elite grade zinc oxide and eugenol sealer. The surfaces of the specimens were covered with red enamel paint, leaving only the apical foramen in a patent condition. The roots were then apically resected and randomly placed into one of four groups. The specimens in each group received the following treatment: group A—cold-burnished gutta-percha; group B—reverse amalgam fillings without varnish; group C—reverse amalgam fillings with varnish in cavity preparation only; and group D—reverse amalgam fillings with varnish in cavity preparation and on beveled root surface. All roots were submerged in 1% methylene blue dye for 2 wk and sectioned longitudinally, and the depth of linear dye penetration was measured. Significantly less leakage occurred when the cavity preparation and the beveled root surface were coated with varnish prior to placement of an amalgam restoration.

Fabrication and Performance of Color Filter Arrays for Solid-State Imagers

A technique has been developed for the fabrication of a color filter array (CFA) to be used in conjunction with a solid-state area sensor to provide three-color image information from a single sensor. The fabrication technique employs sublimable dyes which are heat-transferred through photoresist windows onto a polymer receiving layer. Good edge sharpness and a low dye penetration depth into the polymer have been achieved. The predicted and measured spectral response of the color channels of the composite device are in good agreement. The pattern noise associated with CFA transmittance fluctuations from element to element is on the order of 10 percent.

Fabrication and performance of color filter arrays for solid-state imagers

A technique has been developed for the fabrication of a color filter array (CFA) to be used in conjunction with a solid-state area sensor to provide three-color image information from a single sensor. The fabrication technique employs sublimable dyes which are heat-transferred through photoresist windows onto a polymer receiving layer. Good edge sharpness and a low dye penetration depth into the polymer have been achieved. The predicted and measured spectral response of the color channels of the composite device are in good agreement. The pattern noise associated with CFA transmittance fluctuations from element to element is on the order of 10 percent.