tytin and Dental-Leakage

Dispersalloy with a 0.9% zinc and a non-zinc composition and Tytin with a 1.0%, 0.33% and a non-zinc formula were evaluated. Thirty-nine patients received 247 amalgam restorations, in which these five formulas were randomly placed. Results after 3 years indicate that the zinc-containing alloys had less fracture at the margins than the non-zinc alloys. The data indicate that small amounts of zinc (approximately 1%) play a beneficial role in the serviceability of high copper amalgams.

Topics: Adult; Analysis of Variance; Copper; Dental Alloys; Dental Amalgam; Dental Leakage; Dental Restoration, Permanent; Female; Humans; Male; Materials Testing; Middle Aged; Zinc

The aim of this study was to compare the coronal microleakage of conventional and bonded amalgam coronal-radicular (Nayyar) restorations on endodontically treated molar teeth, because coronal seal is a major factor in the long-term success of endodontic treatment.. Forty extracted human molar teeth were root-filled and prepared for coronal-radicular amalgam restorations. Four groups of 10 teeth were restored with Tytin amalgam and Vitrebond, Superbond D Liner II, Panavia 21, or no adhesive agent. The teeth were placed in India ink for 1 week, and then demineralized and rendered transparent. The ink penetration was assessed with a coded scoring system.. The bonded amalgam groups produced significantly less leakage than did the nonbonded group. No statistically significant differences in leakage were detected among the bonded amalgam groups.. To prevent the reinfection of the endodontically treated molar, it may be preferable to restore the tooth immediately after obturation by employing a bonded amalgam coronal-radicular technique.

Topics: Boron Compounds; Carbon; Coloring Agents; Dental Alloys; Dental Amalgam; Dental Bonding; Dental Enamel; Dental Leakage; Dental Pulp Cavity; Dentin; Dentin-Bonding Agents; Glass Ionomer Cements; Gutta-Percha; Humans; Methacrylates; Methylmethacrylates; Molar; Phosphates; Post and Core Technique; Resin Cements; Root Canal Filling Materials; Root Canal Obturation; Root Canal Preparation; Root Canal Therapy; Statistics as Topic; Surface Properties; Treatment Outcome

This study evaluated the microleakage and interfacial micromorphology of Class V cervical amalgam restorations lined with OptiBond, AElitebond, or Panavia 21.. Unlined amalgams served as control. Cavities were treated with each dentin bonding system according to the manufacturers' instructions and restored with Tytin non-gamma 2 spherical amalgam. After one week of storage in tap water at 37 degrees C, the specimens were thermocycled (1000 cycles, 6-60 degrees C, 30s dwell time). Microleakage was assessed by means of basic fuchsin dye penetration and recorded according to an ordinal scale.. None of the systems tested in this study completely eliminated microleakage. Kruskal-Wallis one-way ANOVA and Mann-Whitney U test found that on the occlusal wall, Panavia 21 and the control group had the least leakage (P<0.05). No statistically significant differences were found at dentin margins (P>0.05). Wilcoxon matched pairs signed rank test found that Panavia 21 and the control group had less leakage at the occlusal than at the dentin margins (P<0.05); when AElitebond and OptiBond groups were evaluated, microleakage at the enamel and at the dentin margins was similar for each group. With the adhesive systems, perhaps the hydrophilic bonding agents incorporated the dye during specimen immersion and/or sectioning.. The use of adhesives may not be as worthy as resin cements for sealing and bonding amalgam restorations to enamel and dentin.

Topics: Adhesives; Analysis of Variance; Dental Alloys; Dental Amalgam; Dental Bonding; Dental Cavity Lining; Dental Enamel; Dental Leakage; Dental Restoration, Permanent; Dentin; Dentin-Bonding Agents; Humans; Methacrylates; Microscopy, Electron, Scanning; Phosphates; Resin Cements; Rosaniline Dyes; Surface Properties; Temperature; Thermodynamics; Tooth Cervix; Water

To compare the microleakage and bond strength exhibited by two light-cured, filled dentin bonding agents, a resin cement, and cavity varnish.. The four test groups of lining agents for amalgam restorations included (LF) Light-cured, Filled resin (Clearfil Liner Bond 2); (LCF) light- and chemical-cured, Filled resin (Clearfil Liner Bond + Protect Liner); (RC) Resin Cement (Panavia 21); and (V) Varnish (Copalite). For each group, 20 Class V cavity preparations were cut in human extracted molars. Tytin amalgam was condensed into the preparation. After storage for at least 24 hrs in distilled water at 37 degrees C, all restorations were subjected to 2500 thermal cycles (8 degrees C to 48 degrees C). After 1 wk, specimens were tested. For the leakage tests, teeth were immersed in 45Ca, sectioned, and radiographs of sections were evaluated and then evaluated by Ridit analysis. Retention samples were tested to failure in tension using an Instron machine and peak load (kg) was recorded.. Compared to varnish, the two dentin bonding agents (LF and LCF) significantly decreased microleakage at the cementum margin but not at the enamel margin. The two dentin bonding agents also exhibited significantly greater retentive strength than either the resin cement or the varnish.

Topics: Calcium Radioisotopes; Dental Alloys; Dental Amalgam; Dental Bonding; Dental Cavity Lining; Dental Cavity Preparation; Dental Cementum; Dental Enamel; Dental Leakage; Dental Materials; Dental Restoration, Permanent; Dental Stress Analysis; Dentin-Bonding Agents; Humans; Image Processing, Computer-Assisted; Methacrylates; Microscopy, Confocal; Molar; Phosphates; Radiopharmaceuticals; Resin Cements; Resins, Plant; Stress, Mechanical; Temperature; Thermodynamics; Time Factors

A tight and long-lasting seal of root-end fillings is of prime clinical importance. A hundred standard bovine root sections, each 3 mm high and with a central pulp lumen of 2.6 mm in diameter, were filled with five commonly used or potential root-end filling materials. At 24 h, or at 3, 6, or 12 months after filling, leakage along these filling materials was determined under a low headspace pressure of 10 kPa (0.1 atm) using a fluid transport model. During the first 3 months, the percentage of gross leakage (> 20 microliters day-1) increased noticeably for Tytin amalgam (from 20 to 100%) and Super-EBA (from 0 to 55%), whereas it decreased noticeably for mineral trioxide aggregate (MTA; from 55% to 0%). Thereafter, the increased leakage of amalgam and Super-EBA decreased with time, whereas the improved seal of MTA was maintained until the end of the experiment. At 3-, 6-, and 12-month time intervals, both glass ionomer cements (Fuji II and Hi Dense) and MTA showed less leakage than the conventional amalgam and Super-Eba, of which amalgam leaked more.

Topics: Aluminum Compounds; Animals; Calcium Compounds; Cattle; Dental Alloys; Dental Amalgam; Dental Leakage; Dentin-Bonding Agents; Drug Combinations; Evaluation Studies as Topic; Glass Ionomer Cements; Longitudinal Studies; Oxides; Retrograde Obturation; Root Canal Filling Materials; Silicates; Statistics, Nonparametric

Dentinal tubules are oriented perpendicularly to the root canal walls but parallel to the lateral walls of class I occlusal preparation. It was hypothesized that the contact surface area of the material may depend on the tubule orientation in the cavity wall to which the material is applied, and that the difference in contact surface may affect the seal provided by the filling material. Standard central lumens, 2.6 mm in diameter and 3 mm high, were machined in human crown or root specimens. After removal of the smear layer with a conditioner, the specimens in each experimental group, consisting of 20 crown and 20 root specimens, were filled with amalgam, Fuji II glass ionomer (with or without varnish), or gutta-percha with Ketac-Endo root canal sealer. A modified fluid transport model was used to test the leakage along the fillings. Selected specimens were then split longitudinally and observed in a scanning electron microscope. The micrographs showed that all the test materials were pressed into the dentinal tubules. The contact surface of the material was calculated to be at least 45% larger in root specimens than in crown specimens, depending on the depth of the tubular penetration of the test material. The leakage results showed that all the test materials leaked less in root specimens than in crown specimens (P = 0.0000 for amalgam, P = 0.0374 for Fuji II with varnish, P = 0.0088 for Fuji II without varnish, P = 0.002 for gutta-percha with sealer). It was concluded that the tubule orientation in the cavity wall may influence the seal provided by certain dental filling materials.

Topics: Dental Alloys; Dental Amalgam; Dental Cavity Lining; Dental Leakage; Dental Pulp Cavity; Dentin; Glass Ionomer Cements; Humans; Microscopy, Electron, Scanning; Root Canal Filling Materials; Root Canal Obturation; Statistics, Nonparametric; Tooth Crown; Tooth Root

To evaluate the effectiveness of the dentin bonding systems (DBS) Tenure, Syntac, Amalgambond and All-Bond 2 using a resin-lined amalgam technique in preventing short-term microleakage in Class V cavity preparations restored with a spherical and an admixed alloy.. Class V cavity preparations were made on the mesial and distal surfaces of non-carious human mandibular molars with the occlusal margins in enamel and gingival margins in cementum. Prepared teeth were randomly assigned to 12 treatment groups (n = 10) consisting of each DBS, no liner and Copalite for both amalgam alloys. Samples were thermocycled, stained and sectioned to evaluate microleakage.. The DBS-lined restorations had significantly less microleakage at both occlusal and gingival margins than the Copalite and unlined restorations. Among DBS, Syntac had significantly more microleakage with both alloys than either All-Bond 2 or Amalgambond. These results do not totally correlate to a previous study which used the same experimental design but included viscous liners in addition to the same DBS, indicating a potential difference between resin-lined versus resin-bonded amalgam techniques in preventing microleakage.

Topics: Analysis of Variance; Dental Alloys; Dental Amalgam; Dental Bonding; Dental Cavity Lining; Dental Leakage; Dental Materials; Dentin-Bonding Agents; Humans; Methacrylates; Resin Cements; Resins, Plant; Statistics, Nonparametric

To answer criticisms of an insufficient number of cycles in thermocycling in an earlier paper (Wendt et al., 1992), this study was initiated to evaluate the effect of different dwell times during long-term thermocycling in microleakage analysis of bonded restoratives.. A total of 90 resin-bonded restorations, Tytin/Liner F, (Kerr/Bisco), APH/Universal Bond 3, (LD Caulk) and Heliomolar/Syntac, (Vivadent), were inserted in Class V preparations in human third molars. Group A restorations were stored in 0.5% basic fuchsin dye for 166 h. Group B restorations were thermocycled for 5000 cycles in 0.5% basic fuchsin dye baths at 5 +/- 1 degrees C and 55 +/- 1 degrees C with a dwell time of 10 s in each bath. Group C was thermocycled as in Group B but with a dwell time of 60 s. Readings by defined criteria were taken from each of two 1 mm sections along the cemental margin.. There were no significant differences (p < 0.05) in the extent of dye penetration at the tooth restoration interface for the thermocycled composite restorations when compared to composite restorations with no thermocycling. There was a significant difference (p < 0.05) in the extent of dye penetration at the tooth restoration interface for the thermocycled amalgam restorations when compared to dye-exposed amalgam specimens with no thermocycling.. During microleakage analysis, the need for thermocycling is dependent upon the extent the restorative is thermally conductive in relation to its mass. The dwell time should be clinically relevant, i.e., 10 s, and is important only if the restorative is thermally conductive.

Topics: Acrylic Resins; Analysis of Variance; Composite Resins; Dental Alloys; Dental Leakage; Dental Marginal Adaptation; Dental Restoration, Permanent; Dentin-Bonding Agents; Hot Temperature; Humans; Materials Testing; Molar, Third; Polyurethanes; Resin Cements; Statistics, Nonparametric; Thermodynamics; Time Factors

To evaluate in vitro the microleakage of various dentin bond/resin liner systems when used with both a spherical and an admixture alloy.. Class V cavity preparations were prepared on 60 noncarious extracted human molar teeth with one margin in enamel and another in dentin and restored with either Dispersalloy or Tytin alloy. Treatment groups utilizing either no liner, Copalite varnish, Amalgambond Plus/HPA, Tenure with Panavia EX Dental Adhesive, Syntac with Dual Cem, and All-Bond 2 with Liner F were tested. Samples were thermocycled, stained, and sectioned to evaluate microleakage.. A significant reduction in microleakage at the enamel and dentin margins was found in all dentin bond system/resin liner groups when compared to unlined and Copalite-lined alloys. There were no significant differences in total microleakage scores between the alloy types. Statistically significant differences in microleakage were detected between some systems. The Tenure with Panavia EX treatment group exhibited a significantly lower total microleakage when used with Tytin. The Syntac/Dual Cem treatment groups exhibited a significantly higher total microleakage when used with Dispersalloy.

Topics: Analysis of Variance; Composite Resins; Dental Alloys; Dental Amalgam; Dental Cavity Lining; Dental Cements; Dental Leakage; Dental Materials; Dentin-Bonding Agents; Humans; Methacrylates; Microscopy, Electron, Scanning; Phosphates; Resin Cements; Resins, Plant; Statistics, Nonparametric

The feasibility of utilizing mercury-free Gallium alloy GF for retrograde filling was investigated by comparing apical microleakage in 184 extracted human teeth. The teeth were divided into four experimental and two control groups. Three experimental groups were apical cavity retrofillings with the Gallium alloy GF, a mercury-containing amalgam, and a glass ionomer. The fourth experimental group was filled with gutta-percha and heat-burnished after apicoectomy. After 24 h, 1 wk, 4 wk, and 12 wk immersion in dye solution, the roots were vertically sectioned, and the deepest point of dye penetration was recorded. The glass ionomer showed the least leakage, followed by the amalgam group and the gallium group (no significant difference). The gutta-percha heat-burnished group displayed the greatest leakage. Gallium alloy GF was shown to have an equivalent sealing potential to dental amalgam for a retrograde filling material.

Topics: Analysis of Variance; Dental Alloys; Dental Amalgam; Dental Leakage; Gallium; Glass Ionomer Cements; Gutta-Percha; Humans; Retrograde Obturation; Root Canal Filling Materials

A phantom head model was modified to simulate as closely as possible the limited access encountered during periapical surgery on maxillary anterior teeth. Extracted human maxillary anterior and mandibular canine teeth were placed in this model in a standardized position for root resection, retrograde cavity preparation and filling with amalgam. Three different designs of retrograde cavities were evaluated: the conventional class 1 cavity, the slot cavity and a previously unreported approach, the funnel cavity. Upon completion of the retrograde filling, the teeth were removed from the model and subjected to microleakage tests by placing radiolabelled lipopolysaccharide in a reservoir created coronal to the retrograde fillings. Leakage was quantified by measurement of radioactivity in scintillation counter. It was found that the retrograde fillings in the funnel cavity leaked significantly less than those in the other two cavity designs. There was no statistically significant difference in leakage between the conventional class 1 and the slot cavities up to the thirtieth day 30.

Topics: Aggregatibacter actinomycetemcomitans; Dental Alloys; Dental Amalgam; Dental Leakage; Humans; Lipopolysaccharides; Models, Dental; Phantoms, Imaging; Radioactive Tracers; Retrograde Obturation; Root Canal Filling Materials; Root Canal Preparation

Different formulations of amalgam have physical properties that may make them behave differently in the often-contaminated root end environment. Five different brands of amalgam were evaluated for microleakage of root-end fillings placed in extracted human teeth. These included a zinc-free spherical amalgam, a zinc-free admixture amalgam, two zinc-containing admixture amalgams, and a zinc-containing lathe-cut amalgam. The amalgams were placed either into dry root-end preparations or into preparations contaminated with human blood. The fluid filtration method was used to measure microleakage at 1, 2, 4, 8, 12, and 24 wk after placement. Analysis of variance revealed significant differences in the rates of microleakage at every measurement period. Scheffé's test showed that the zinc-free spherical amalgam had significantly greater leakage than all the other products evaluated. There were no significant differences between any of the other products. Blood contamination did not adversely affect the seal of any amalgam.

Topics: Analysis of Variance; Dental Alloys; Dental Amalgam; Dental Leakage; Evaluation Studies as Topic; Humans; Retrograde Obturation; Root Canal Filling Materials; Zinc

The sealing ability of two potential retrograde root filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol) was compared with that of amalgam using three methods of assessment: bacterial leakage, confocal microscopy and Indian ink leakage. the root canals of 80 extracted human single-rooted teeth were prepared. All the teeth were apicected, retrograde cavities were prepared and then divided into four equal groups of 20 teeth. The teeth were sterilised by autoclaving and the retrograde cavities filled with the test materials. In the control group, retrograde cavities in 10 teeth were left unfilled while cavities in another 10 teeth were sealed with cyanoacrylate cement. The teeth were first subjected to a bacterial leakage test using Enterococcus faecalis as a leakage marker. After which, the adaptation of the retrograde root fillings was assessed using a confocal optical microscope. Finally, the teeth were processed for the Indian ink leakage test. Bacterial leakage occurred in more teeth filled with amalgam compared with both Vitrebond and Kalzinol (P<0.001), between which there were no differences. With confocal microscopy, the size of the marginal gap was largest with amalgam and smallest with Vitrebond; all differences were statistically significant (<0.001). Finally, there was more Indian ink penetration with amalgam compared with both Vitrebond and Kalzinol (P<0.001) but there were no differences between Vitrebond and Kalzinol. Although there were individual differences within samples, overall, the three methods of assessment produced similar results. The sealing ability of Vitrebond and Kalzinol was similar and both materials were better than amalgam.

Topics: Carbon; Chi-Square Distribution; Coloring Agents; Dental Alloys; Dental Amalgam; Dental Leakage; Dental Marginal Adaptation; Drug Combinations; Enterococcus faecalis; Eugenol; Formaldehyde; Glass Ionomer Cements; Humans; Microscopy, Confocal; Retrograde Obturation; Root Canal Filling Materials; Statistics, Nonparametric; Zinc Oxide

This study evaluated the preparation of root-end cavities using an ultrasonically activated file, and the obturation of such cavities. In the first part, the root canals of 40 extracted teeth were prepared to size 40 and irrigated with NaOCl and EDTA. The root ends were resected and the teeth inoculated with Enterococcus faecalis, incubated for 10 days and divided into four groups: control; saline; irrigation; hand instrumentation performed via a retrograde approach up to size 50 using saline irrigant; ultrasonic instrumentation with prebent size 40 K-flex file inserted into a Piezon Master using saline irrigant. The teeth were fixed, sectioned longitudinally and viewed under scanning electron microscopy. Bacterial and smear layer scores were obtained at 1, 3, and 5 mm from the resected end. The bacterial scores for control and saline groups were similar; the scores for each instrumentation group were significantly lower than the control group (P<0.001). In addition, there were significantly fewer bacteria in the ultrasonic group compared with the hand instrument group (P<0.001). The smear layer scores for control and saline groups were similar, and significantly lower than in either instrumentation group (P<0.001). In the second part, root-end cavities were ultrasonically prepared in 20 extracted teeth. Ten cavities were filled with amalgam, and 10 with thermoplasticized gutta-percha and Grossman's sealer. After 24-h storage, the root ends were immersed in dye for 48 h. Cross-sectional slices of the obturated part of the root were evaluated using both light and confocal microscopy for dye leakage along the interface of filling material and dentine. There were no statistical differences between the leakage of amalgam and gutta-percha root-end fillings, nor between the two methods of microscopy.

Topics: Dental Alloys; Dental Leakage; Dental Pulp Cavity; Dentin; Gutta-Percha; Humans; Microscopy, Electron, Scanning; Retrograde Obturation; Root Canal Filling Materials; Root Canal Preparation; Smear Layer; Statistics, Nonparametric; Tooth Root; Ultrasonic Therapy

The most recent advancement in silver amalgam is use of resin formulations to bond metal to tooth both chemically &/or physically, Since, historically, amalgam has been used successfully without adhesion to tooth, obvious clinical question is: Why is bonding now desirable? Two major clinical reasons to bond are: (1) Adhesive can increase fracture resistance of amalgam restored teeth & decrease cusp fractures; & (2) Seal provided by adhesive can greatly decrease, & often eliminate post-operative sensitivity. Following report summarizes CRA laboratory study of shear bond strength & sealing capability of 23 commercial adhesives used to bond 2 types of silver amalgam to tooth structure.

Topics: Composite Resins; Dental Alloys; Dental Amalgam; Dental Bonding; Dental Cements; Dental Leakage; Dental Restoration, Permanent; Dental Stress Analysis; Dentin Sensitivity; Humans; Materials Testing; Molar

This study was designed to evaluate one of the commonly used scoring systems--Score I--(categories from 0-5) to other two suggested scoring systems--Score II & III--(categories from 0-1 and 0-2 respectively), to test the degree of dye penetration for leakage studies. Class V cavities were prepared on 100 extracted human upper central incisors and filled with light cured composite. Herculite, and high copper amalgam. Tytin. All teeth were immersed in sodium fluorescein dye to test the degree of dye penetration. The results revealed that the suggested score II is very easy, simplified and representative but not indicative regarding the severity of dye penetration as score I. Score III are indicative and obvious discussion can be obtained rather than score I. For any leakage study the use of non parametric measurement is preferable than parametric ones.

Topics: Dental Alloys; Dental Caries; Dental Cavity Preparation; Dental Leakage; Dye Dilution Technique; Fluorescein; Humans; In Vitro Techniques; Incisor; Maxilla; Random Allocation; Resin Cements; Statistics, Nonparametric

A self-setting apatite cement, EBA cement, and amalgam with varnish were tested for root end sealing ability using a fluid filtration and dye technique. Single-rooted human teeth were prepared in vitro to receive root end fillings. Experimental groups were amalgam with two layers of varnish, EBA cement with dry cavity, EBA cement within a wet cavity, apatite cement within a dry cavity, and apatite cement within a wet cavity. Fluid filtration measurements were made at 6, 24, and 7 days, and 1 and 3 months. Each specimen was also subjected to a dye leakage test using Procion Green dye at 3 months. Results indicated that apatite cement provided a comparable seal to amalgam and EBA cement. This finding, in conjunction with its excellent biocompatibility, suggests that apatite cement is an acceptable alternative to present-day root end filling materials.

Topics: Aluminum Oxide; Apatites; Dental Alloys; Dental Amalgam; Dental Cements; Dental Leakage; Evaluation Studies as Topic; Humans; Retrograde Obturation; Root Canal Filling Materials; Statistics, Nonparametric; Water

Topics: Dental Alloys; Dental Amalgam; Dental Leakage; Dental Restoration, Permanent; Dentin Sensitivity; Humans; Materials Testing; Particle Size; Pressure

Two dentin bonding agents that contain phosphorus esters, (Clearfil Photo Bond and Panavia), and a bonding agent for porcelain, (Clearfil Porcelain Bond), have been introduced for bonding to enamel, dentin, amalgam, cast metal alloys and porcelain. The shear bond strengths were determined to enamel (Procedure A), to dentin (Procedure B), to amalgam (Procedure C), of amalgam to dentin (Procedure D), to cast metal alloy (Procedure E) and to porcelain (Procedure F). Also the quantitative microleakage of Class V restorations in cementum (dentin) was evaluated (Procedure G). The components were applied as directed by the manufacturer and a light-cured resin composite for posterior teeth, (Clearfil Photo Posterior) used. The mean +/- SD of the shear bond strengths recorded in MPa were: A = 24.15 +/- 3.65; B = 11.30 +/- 3.12; C = 13.77 +/- 3.42; D = 4.26 +/- 0.92; E = 17.84 +/- 3.19; F = 13.45 +/- 4.12. The quantitative microleakage (G) was 0.55 +/- 0.34 mg dye/restoration.

Topics: Analysis of Variance; Chromium Alloys; Composite Resins; Dental Alloys; Dental Amalgam; Dental Bonding; Dental Cements; Dental Enamel; Dental Leakage; Dental Porcelain; Dentin; Dentin-Bonding Agents; Esters; Evaluation Studies as Topic; Humans; Materials Testing; Microscopy, Electron, Scanning; Phosphates; Resin Cements; Tensile Strength

The apical seal of amalgam retrograde fillings was evaluated in 86 extracted teeth. The experimental groups included retrofillings of amalgam alone, amalgam with a cavity varnish interface, and amalgam with a root canal sealer interface. After a 3-month immersion of the teeth in Higgins ink and subsequent clearing process, statistical analysis of ink penetration measurements showed significantly less leakage (p < 0.001) around amalgam retrofillings when using a root canal sealer as an interface between the retrograde cavity preparation and the condensed amalgam.

Topics: Dental Alloys; Dental Amalgam; Dental Cavity Lining; Dental Leakage; Dental Materials; Humans; Lacquer; Resins, Plant; Retrograde Obturation; Root Canal Filling Materials; Zinc Oxide-Eugenol Cement

Various techniques for applying two types of varnish to control microleakage of Class V amalgam restorations were compared in vitro. The drying time for each layer of varnish with a gentle air spray was varied, including delays in applying the second coat and the placement of the amalgam restoration. Microleakage was recorded by dye penetration. Both varnishes were inefficient at reducing dye penetration at the gingival wall. There were no statistical differences in dye penetration at the gingival wall between the two varnishes, regardless of the method of application, or the presence of varnish. Both varnishes exhibited good sealing properties at the occlusal wall when used according to the manufacturer's instructions, but varnish application was technique-sensitive. Short-cuts in the procedure may increase leakage; too short a drying time of either varnish can cause microleakage similar to the control group without a varnish.

Topics: Analysis of Variance; Chi-Square Distribution; Dental Alloys; Dental Amalgam; Dental Cavity Lining; Dental Cements; Dental Leakage; Dental Materials; Dental Restoration, Permanent; Humans; Lacquer; Resins, Plant

Currently there is no "standard" finishing and polishing procedure for dental amalgam restorations. This investigation evaluated the effect of four different finishing techniques on the durability of dental amalgam restorations as determined by the marginal breakdown. Burnishing immediately before carving or as part of the condensation process seems to improve the carving characteristics of the amalgam.

Topics: Dental Alloys; Dental Amalgam; Dental Leakage; Dental Occlusion; Dental Polishing; Humans; Microscopy, Electron, Scanning; Surface Properties

Calcium hydroxide has been shown to be an effective medium for the in vivo microleakage testing of amalgams. The purpose of this study was to determine the relative effectiveness of several forms of calcium hydroxide in the measurement of this clinical problem. It was also the purpose of this study to determine whether a relationship exists between the pH of the Ca(OH)2 liner and its ability to detect microleakage. Standardized Class V preparations were generated on the buccal surfaces of extracted molars. The axial walls of the preparations were based either with Dycal, Dycal VLC, Pulpdent Liquid, or pure Ca(OH)2. A series of teeth without a calcium hydroxide base served as the negative control. All teeth were restored with a spherical amalgam and kept in de-ionized water. The surfaces of the restorations were then subjected to 20 mL of 2 degrees C water for a period of one min. After three min, a color-indicating pH paper was positioned over the restored area for detection of the presence of hydroxyl ions at the amalgam/tooth interface. Regardless of the form of calcium hydroxide, all indicated extensive microleakage immediately after insertion of the restoration. In all cases, the number of samples generating positive results for leakage decreased over a period of time. The rate of decrease, however, was substantially dependent upon the form of calcium hydroxide used as well as its pH. The reagent grade of Ca(OH)2 generated the greatest percentage of positive results for the longest duration.

Topics: Calcium Hydroxide; Dental Alloys; Dental Cavity Lining; Dental Leakage; Humans; Hydrogen-Ion Concentration; Materials Testing

The adaptation and sealing ability of a light-cured glass ionomer cement when used as a retrograde root filling was assessed using a confocal optical microscope with and without a fluorescent dye. This material was compared with a conventional glass ionomer cement and amalgam. The root canals of 60 extracted human single-rooted teeth were prepared and filled with gutta-percha and sealer. All the teeth were apicected, retrograde cavities were prepared, and then divided into three groups of 20 teeth each and filled with the test materials. The light-cured glass ionomer cement was well adapted to the retrograde cavity and apicected root surface. Within the retrograde cavity the cement was often well adapted to one wall, but gaps were found on the opposite cavity wall. This was probably caused by the polymerization contraction of the material. In contrast, the amalgam retrograde root fillings were poorly adapted to the cavities, with gaps between the cavity walls and amalgam. This group exhibited the poorest sealing ability as measured by the extent of dye penetration. The conventional glass ionomer cement was often found smeared over the root face, and there were unfilled voids at the base of some retrograde cavities. The results of the dye leakage study were analysed statistically. The sealing ability of the light-cured glass ionomer cement was significantly better than that of amalgam (P less than 0.001). The dye penetration around the light-cured glass ionomer cement and the conventional glass ionomer cement was not significantly different (P greater than 0.05). However, the sealing ability of the conventional glass ionomer cement was significantly better than that of amalgam (P less than 0.05).

Topics: Analysis of Variance; Dental Alloys; Dental Leakage; Glass Ionomer Cements; Humans; Materials Testing; Retrograde Obturation; Root Canal Filling Materials; Silicate Cement

The in vitro sealing ability of Tytin amalgam, Ketac-Silver, and Prisma VLC Dycal was compared. Roots of extracted teeth were perforated laterally. After the defects were repaired, the teeth were immersed in dye for 10 days and then sectioned, and the linear extent of dye penetration was measured. Statistical analysis showed that the Prisma VLC Dycal group exhibited significantly less dye penetration than the other two groups (p less than 0.01). No difference was found between the Tytin and Ketac-Silver groups.

Topics: Calcium Hydroxide; Cermet Cements; Cuspid; Dental Alloys; Dental Amalgam; Dental Cements; Dental Leakage; Glass Ionomer Cements; Humans; Minerals; Root Canal Filling Materials; Tooth Root

The purpose of this study was to compare microleakage around two types of restorations lined with polyalkenoate (glass ionomer) cements after thermocycling. Preparations were made in 48 molars to a diameter and depth of 2.0 mm. Half of the preparations were lined with glass ionomer, and the remainder were not lined. Dental amalgam or glass ionomer restorative material was placed and the amalgams were left unburnished and unpolished. Selected restorations were thermocycled 625 times between 4 degrees C and 50 degrees C. Teeth were immersed in 0.5 per cent methylene blue solution, sectioned and visually scored for microleakage at X 100 magnification. Data analysis indicated significant differences in microleakage because of: thermocycling (chi 2 = 103.38, d.f. = 19,2P less than 0.0004); presence of glass ionomer liners (chi 2 = 53.28, d.f. = 19,2P less than 0.0001); and type of restorative material (chi 2 = 103.44,d.f. = 19,2P less than 0.0004). The use of a glass ionomer liner significantly reduced microleakage in both amalgam and glass ionomer restorations when subjected to thermocycling.

Topics: Chi-Square Distribution; Dental Alloys; Dental Amalgam; Dental Cavity Lining; Dental Cements; Dental Leakage; Dental Restoration, Permanent; Glass Ionomer Cements; Hot Temperature; Humans; Maleates

Topics: Calcium Radioisotopes; Copper; Dental Alloys; Dental Amalgam; Dental Cavity Lining; Dental Leakage; Dental Materials; In Vitro Techniques; Lacquer; Resins, Plant; Time Factors

On the basis of reports of an increased incidence of postoperative sensitivity associated with the use of a particular spherical amalgam alloy, an investigation of in vitro marginal leakage was initiated. An air pressure test was applied to simulated Class I restorations made from this alloy and a control alloy. Factors such as mix plasticity, condensation force, and condensation technique also were examined. The results showed that the spherical alloy in question had a greater tendency for marginal leakage than the control alloy. For both alloys studied, the following factors are important in reducing marginal leakage: increased plasticity of the mix; increased condensation force; condensation of each increment directly along or against cavity walls in overlapping thrusts; and burnishing the amalgam after condensation. Although it is not known what percentage of postoperative sensitivity is caused by leakage of amalgam restorations, the results of this study indicate that leakage can be minimized by using optimum amalgam manipulative procedures and that a reduced incidence of postoperative sensitivity is likely to result.

Topics: Chemical Phenomena; Chemistry, Physical; Dental Alloys; Dental Amalgam; Dental Leakage; Dental Polishing; Dental Restoration, Permanent; In Vitro Techniques