Cavity Liner Research Articles

Biologic effects of dental materials: 5. Effect of cavity liners on HeLa cells in vitro

The cytotoxicity of cavity liners and varnishes was studied by means of an in vitro tissue culture cell system. The cytotoxicity of the liners was found to be greater than the composite materials for which they are intended as liners. While all the liners were toxic, the 3M liner was found to be the least damaging to the tissue culture cells.

Fluoride release from varnish-coated silicates and from cavity liners and fissure sealants.

abstract— The fluoride release of varnish‐coated silicates and liners and sealants was studied by measuring the uptake of the released fluoride by synthetic hydroxyapatite. Silicate specimens were made and coated with cavity varnish. The specimens were shaken in solution with the apatite for 7 weeks. The apatite was analyzed for fluoride each week and the specimens were then transferred to a fresh solution with new apatite. The varnish reduced the fluoride release during the first three weeks, but after that time the release from the varnish‐coated specimens was the same as that from the uncoated specimens. The release from the liners and sealants was studied by coating composite resin specimens with the material. The resin contained no fluoride. The specimens were shaken in solution with apatite and the fluoride uptake was measured each week in the same manner as for the silicate specimens. The liners showed an initial release of fluoride. When the two different sealants were applied as two layers, only one of the brands showed initial release of fluoride. Five layers of sealant resulted in an initial release from both brands.

The occurrence of secondary caries-like lesions in vitro. The effect of a fluoride cavity liner and a cavity varnish.

The occurrence of secondary caries-like lesions in vitro. The effect of a fluoride cavity liner and a cavity varnish.

Effect of addition of Cafpo3 to a zinc oxide-eugenol base liner on the michrohardeness and fluoride content of dentin.

Addition of fluoride to a cavity liner increased the microhardness of the underlying dentin.

Galvanic degradation of amalgam restorations.

Amalgam restorations in contact with saliva and tissue fluid act as concentration cells. The galvanic current is associated with selective attack of the γ 2 phase and loss of mechanical properties. Tin is deposited in the underlying dentin. Cavity liners do not stop the degradation.

Status Report on Cement Bases, Cavity Liners, Varnishes, Primers, and Cleansers

Status Report on Cement Bases, Cavity Liners, Varnishes, Primers, and Cleansers

Pulpal reaction to composite resin restorations

\/ omposite resin materials appear to be gaining in popularity. A report of their physical properties implied that they are superior to silicate cement and the coldcuring acrylic resins. In some situations composite resin materials are suitable for use in the restoration of posterior teeth.l Histologic studies of the effect of composite resin materials on the pulp are few and are concerned mainly with Addent 35t-the first such material to appear on the market. It has been suggested that the pulp reaction to this resin may be slightly less “severe” than to other cold-curing materials, and it was apparently difficult to find an effective liner that would prevent reactions to the Addent 35.* Stanley, Swerdlow, and Buonocore3 found that without a liner this material gave a mild response at first but that it increased in intensity with time. They considered that the proved polyvinyl cavity liner recommended for Addent 35 did not always provide adequate protection of the p~lp.~ In another study conducted by Baume and FioreDonno, pulp injury was found to be particularly severe under deep cavities with Addent 35, and the polyvinyl liner recommended by the manufacturer did not protect the pulp, though calcium hydroxide paste did. Sayegh and Reed5 studied the response beneath 36 Blendantl fillings in human teeth and, as a rule, found a mild response. No histologic examinations of the effect on the pulp of the new materials Addent 12 and Adaptics appear to have been published. The question of whether these materials are acceptable from the biologic aspect remains unanswered, and this applies to whatever kind of protection is used should damage to the pulp occur. In a separate study, 6 bacteria were detected on the walls of 56 of 66 unlined cavities restored with Adaptic, Addent 12, or DFR.11 Under 19 of these restorations, bacteria were observed in the dentinal tubules and in the pulps of three teeth. Only with

Preliminary Histopathological Study of a New Quartz-Filled Composite Dental Restorative Material

An experimental composite dental restorative material was studied histologically by means of restorations, with and without cavity liners, in the teeth of rhesus monkeys. A commercially available composite material, with liner, was used for comparison. There was a definite, statistically significant, downward trend of pulpal response with time for all materials tested, although there was no significant difference among them. The experimental restorative appeared to produce no more pulpal response without a liner than when liners were used.

Pulpal Protection by a Cavity Liner Applied As a Thin Film Beneath Deep Silicate Restorations

Before deep silicate restorations were placed in 40 contralateral pairs of permanent premolars, a thin film of a polystyrene liner was applied in one randomly chosen cavity of each pair. The observation periods were one and four weeks. In all but one of the 40 teeth, the liner gave satisfactory protection.

Cavity liner, penetration liners and closures of a prestressed concrete pressure vessel for a gas-cooled power reactor

The design criteria of the PCRV cavity liner and the penetration liners and closures are discussed, including the requirements for anchoring the liners to the concrete and the closure design requirements. Materials of construction are identified including discussion of special impact strength requirements and neutron radiation effects. Construction consideration, including inspections, tests, and quality assurance employed during construction are identified. The application of these requirements to the Fort St. Vrain reactor is discussed.

Marginal seal afforded by n-butyl and isobutyl cyanoacrylates as cavity liners

Teeth subjected to identical conditions of treatment, oral environment, and temperature cycling apparently demonstrated different leakage patterns. Those cycled in the fluorescein showed slight evidence of leakage when viewed under ultraviolet light, while those teeth cycled in the C 14-labeled glucose showed considerable leakage. From this study, it appears that radioactive tracer techniques are essential to demonstrate leakage patterns that might not be revealed in dye-penetration studies. 7

Penetration of metallic ions from restorations into teeth

The efflux of metal ions from metal restorations and their penetration into dental tissues have been studied with the use of sophisticated techniques. The results show significant concentrations of metal ions in both enamel and dentin from amalgam, chromium-cobalt, and cast-gold restorations after short periods in or on the teeth. The highest concentrations occurred in the regions closest to the restorations, especially within the dental tubules cut during cavity preparation. It was also shown that use of pure cohesive-gold or nearly pure cast-gold restorations or heat-treatment (homogenization) of gold castings for sufficiently long periods reduced the corrosion of gold restorations and the penetration of corrosion products into dental tissues. Use of a cavity liner was found to prevent migration of corrosion products from metal restorations into teeth.

Pulpal response in rat molars to a new restorative material without a liner

The present study evaluated the pulpal response to Addent 35 used without a cavity liner. Only 3 test specimens showed any adverse pulpal response. Severe hyperemia was observed in the pulp of one tooth beneath a cavity in a rat put to death 2 days postoperatively. Leukocytic infiltration and associated hyperemia was evident in one tooth of a rat put to death after 7 days. In the 30 day group, one of the test teeth was hyperemic. Reparative dentin was present in all test teeth, and in 7 of the 9 control teeth in the 30 day group. Although the average amount of reparative dentin formed in the test teeth during the 30 days was twice the amount that was formed in the control teeth, this difference was insignificant (p > 0.05, t-test). No adverse pulpal responses were observed in the control specimens at any time.

Pulp reactions to anterior restorative materials

Two composite dental acrylic-type resins with improved physical and esthetic properties were tested for level of toxicity compared with that of silicate and zinc oxide-eugenol. Modification of application technic and cavity liners is needed before these new materials can be recommended for general clinical use.

Use of radioactive tracers to determine the protective effect of cavity liners.

Use of radioactive tracers to determine the protective effect of cavity liners.

Letters to the Editor: Cavity liners

Letters to the Editor: Cavity liners

Cavity liner thicknesses and retentive characteristics

Thickness of five cavity liners varied and were influenced by the application method and prior evaporation of the varnishes. Differences in thickness did not appear to affect amalgam retention.

Cavity liners and dentin treatment

Cavity liners and dentin treatment

Retentive properties of dental cements

The relative retentive properties of various luting agents were investigated by measurement of the tensile force necessary to remove cast gold, occlusal inlays seated with the different cements. The influence of the cement base and cavity liners on retention was also studied. 1. 1. Inlays cemented with the zinc phosphate cement (Tenacin) offered the greatest resistance to removal. The results obtained with Kryptex, the silico-phosphate cement, were essentially the same but the retention decreased when the silicate cement, New Filling Porcelain, was used. 2. 2. Inlays cemented with the zinc oxide-eugenol cements, Temrex, and Temporary Cement, required less force to remove than when the same restorations were seated with the phosphoric acid cements. There were some differences between individual products. One material, Temp-Bond, designed for temporary cementation, exhibited considerably less retention than the others. 3. 3. Varnish-type cavity liners, Copalite and Repelac, did not appreciably alter the retentive properties of zinc phosphate cement, although use of Pulpdent, a liner consisting of a suspension of calcium hydroxide, did impair the retention somewhat. 4. 4. The retention of inlays cemented with zinc phosphate cement was not affected by placing either a zinc oxide-eugenol (Cavitec) base or calcium hydroxide (Dycal) base in a depression in the floor of the cavity.

Continued Studies on the Permeability of Cavity Liners

Continued Studies on the Permeability of Cavity Liners