Lack of correlation between the amount of eugenol released from zinc oxide-eugenol sealer and cytotoxicity of the sealer

The purpose of this study was to examine a possible correlation between the eugenol released from a zinc oxide-eugenol sealer (Canals) and the degree of cytotoxicity. The cytotoxicity and eugenol release from root canal filling material containing eugenol was examined for test solutions at several experimental periods. No positive correlation was found between eugenol release and cytotoxicity of the root canal filling material.     

Biologic properties of eugenol and zinc oxide-eugenol. A clinically oriented review.

Eugenol-containing dental materials are frequently used in clinical dentistry. When zinc oxide-eugenol (ZOE) is applied to a dentinal cavity, small quantities of eugenol diffuse through the dentin to the pulp. Low concentrations of eugenol exert anti-inflammatory and local anesthetic effects on the dental pulp. Thus use of ZOE temporary filling may facilitate pulpal healing; on the other hand, high eugenol concentrations are cytotoxic. Direct application of eugenol to pulp tissue may result in extensive tissue damage. The ability of ZOE-based endodontic sealers to influence periapical tissue healing is considered in view of eugenol's anti-inflammatory and toxic properties.     

Temporary zinc oxide–eugenol cement: eugenol quantity in dentin and bond strength of resin composite

Uptake of eugenol from eugenol‐containing temporary materials may reduce the adhesion of subsequent resin‐based restorations. This study investigated the effect of duration of exposure to zinc oxide–eugenol (ZOE) cement on the quantity of eugenol retained in dentin and on the microtensile bond strength (μTBS) of the resin composite. The ZOE cement (IRM Caps) was applied onto the dentin of human molars (21 per group) for 1, 7, or 28 d. One half of each molar was used to determine the quantity of eugenol (by spectrofluorimetry) and the other half was used for μTBS testing. The ZOE‐exposed dentin was treated with either OptiBond FL using phosphoric acid (H₃PO₄) or with Gluma Classic using ethylenediaminetetraacetic acid (EDTA) conditioning. One group without conditioning (for eugenol quantity) and two groups not exposed to ZOE (for eugenol quantity and μTBS testing) served as controls. The quantity of eugenol ranged between 0.33 and 2.9 nmol mg^?1 of dentin (median values). No effect of the duration of exposure to ZOE was found. Conditioning with H₃PO₄ or EDTA significantly reduced the quantity of eugenol in dentin. Nevertheless, for OptiBond FL, exposure to ZOE significantly decreased the μTBS, regardless of the duration of exposure. For Gluma Classic, the μTBS decreased after exposure to ZOE for 7 and 28 d. OptiBond FL yielded a significantly higher μTBS than did Gluma Classic. Thus, ZOE should be avoided in cavities later to be restored with resin‐based materials.     

HEMA diffusion from dentin bonding agents through various dentin thicknesses in primary molars

PURPOSE: To evaluate in vitro HEMA diffusion amounts from three dentin-bonding systems in primary molars with various remaining dentin thicknesses. METHODS: Occlusal cavities were prepared with remaining dentin thickness of 0.5, 1 and 2 mm respectively. Chambers that contain 1 ml of distilled water were attached to each tooth. The groups were treated with Total Etch + Syntac Single Component, Syntac Single Component and Clearfil SE Bond. Water eluates were removed after 72 hours for analyses by HPLC. RESULTS: The cumulative HEMA release amounts were significantly different between all groups (P< 0.05). Decreasing dentin thickness and acid-etching significantly increased pulpward diffusion of HEMA.     

The pharmacologic and toxicological properties of zinc oxide-eugenol

An explanation of the therapeutic effects of zinc oxide-eugenol when placed in contact with intact or carious dentin, and the toxic effects of zinc oxide-eugenol when placed in contact with soft tissue or tissue cultures is presented to allow for the rational, safe, and effective use of the material.     

Retentive and compressive strengths of modified zinc oxide-eugenol cements

OBJECTIVES: This investigation sought to improve the handling and physical properties of a commonly used temporary zinc oxide-eugenol cement by changing the base/accelerator (B/A) ratio or combining it with a petroleum jelly or fluoride varnish. METHODS: Twelve modifications of a temporary cement were evaluated in terms of retentive strength, compressive strength at 24 h, film thickness and by scanning electron microscopy. RESULTS: Decreasing the B/A mixing ratio increased the retentive and compressive strengths, but reduced the film thickness of the cement. By increasing the percentage of incorporated petroleum jelly or fluoride varnish in the cement, there was a progressive decrease in the retentive and compressive strengths and in film thickness. CONCLUSIONS: Modifications of a zinc oxide-eugenol temporary cement to change the B/A ratio or to incorporate additives resulted in variations in physical properties. All modified forms of the cement had a film thickness less than 25 microns and a compressive strength below 35 MPa. With a wide range of retentive strength, modified forms of zinc oxide-eugenol cement may be found to have diverse clinical applications.     

Concentration of eugenol apically released from zinc oxide-eugenol-based sealers

This study investigated the amount of eugenol released from a zinc oxide-eugenol-based sealer at the apex of teeth filled according to two techniques: the single-cone and the Thermafil. The crown of 10 maxillary central incisors was removed, and the canal was prepared with ProFile to a size 30 under NaOCl irrigation. The patency of the apex was checked with a #8 K-file between each ProFile. Five roots were filled with a Thermafil #30 and 0.03 g of Sealite; five roots were filled using a Lentulo with 0.07 g of sealer and a gutta-percha cone #30. The powder/liquid ratio of the sealer was of 5/1. The concentration of eugenol released in phosphate-buffered saline was spectrofluorimetrically determined immediately after sealing, after 1 day, and after 1 month of storage. The roots filled with the single-cone technique released significantly more eugenol than these filled with Thermafil immediately after sealing (p = 0.002); but, after 1-day or 1-month storage, there was no difference. For both techniques, eugenol concentration decreased over time (p = 0.01): the immediate concentration was higher than the 1-day concentration (p = 0.04). Eugenol concentration after 1-month storage was undetectable. The results of this work show that the level of eugenol released from a zinc oxide-eugenol-based sealer beyond the apex is very low and decreases over time.     

pH changes and calcium ion diffusion from calcium hydroxide dressing materials through root dentin.

The purpose of this study was to evaluate Ca2+ and OH- diffusion properties through root dentin by using different calcium hydroxide (CH) dressing materials. Twenty-eight single-rooted teeth were instrumented and external defects were created on the root surface. 17% EDTA was used to eliminate the smear layer. All surfaces except the external defects were sealed, and the teeth were placed in normal saline. Ca2+ concentrations and the pH in the saline were determined for 3 days as the control period. After removing the teeth from normal saline, they were filled with: (i) DT Temporary Dressing CH; (ii) CH powder and normal saline; (iii) TempCanal; and (iv) CH points. The teeth were then placed in normal saline, and Ca2+ concentrations and pH values were measured at 1, 3, 7, 14, and 28 days. Nonsetting CH pastes gradually released Ca2+, whereas this increase was absent from CH points. None of the test materials induced a pH increase in the media during the observation period. This study demonstrated that, when nonsetting CH pastes are applied to the root canal, diffusion of Ca2+ without an increase in pH to the surrounding media occurs. This implies that these type of material are more suitable than CH points for treatment of external root resorption.     

Influence of eugenol contamination on the wetting of ground and etched dentin

Forty third molars were sectioned parallel to the occlusal surface in order to expose superficial and deep dentin. Exposed surfaces were ground flat with 500-grit sandpaper. Contact angle measurements were performed to assess wettability using the ADSA-CD technique. Specimens were divided into two groups. Group 1 was the control group (no contamination). Group 2 served as the test group. Dentin surfaces were covered with a provisional eugenol-containing material (IRM) and were placed into a humidor at 37 degrees C for one week. The provisional material was removed. Wettability measurements of the two groups were made with water on ground dentin, with water and resin on etched dentin. Data were statistically analyzed by ANOVA, Student-Newman-Keuls multiple comparison and Student t-tests. Eugenol contamination did not affect the dentin wetting. Acid etching significantly diminished contact angle values. Dentin wetting was greater on deep dentin than on superficial dentin.     

Solubility of zinc oxide-eugenol and calcium hydroxide cements in simulated dentinal fluid

The solubility of four dental cement bases was measured in simulated dentinal fluid and distilled water to evaluate the relevancy of the American Dental Association solubility test for cement bases in contact with vital dentine. A simulated dentinal fluid was formulated utilizing glucose, distilled water, and sterile human plasma. Cement-base samples were immersed in either distilled water or simulated dentinal fluid at 37 degrees C in a shaker water-bath for 1, 2, or 3 months. Weight loss values were compared utilizing a three-way analysis of variance. Zinc oxide-eugenol cements were significantly more soluble in simulated dentinal fluid than distilled water, while the calcium hydroxide cement bases were significantly more soluble in distilled water than simulated dentinal fluid.