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The aim of this study was to compare the volumetric expansion of gutta-percha in the presence of eugenol or physiologic saline over time. Sections of gutta-percha cones were scanned to determine their total volume and surface area. They were then placed in sealed test tubes with either 2 microL eugenol or 2 microL saline and allowed to soak for 24 hours, 7 days, or 30 days. The results were scanned again to determine the volumetric changes in the material after placement in the test solutions. The results were statistically analyzed by using t tests and analysis of variance. Specimens soaked in eugenol showed a dramatic increase in volumetric expansion versus the saline group at all time periods. Sealers that incorporate eugenol could be attributed to gutta-percha volumetric expansion over time, thereby creating a better seal of the obturation material.

Eleven sealers, including Resilon sealer, were mixed according to manufacturer's instructions. Setting times were determined in both aerobic and anaerobic environments. Two samples of each sealer were mixed and placed in the following conditions: (a) uncovered in an aerobic incubator; (b) covered with a glass cover-slip in the aerobic incubator; (c) covered with phosphate buffered saline in an aerobic incubator; (d) uncovered in an anaerobic incubator; (e) light cured and then placed in the aerobic incubator (Resilon only). All samples were tested for setting times with a Gillmore needle at 15, 30, and 60 minutes, then hourly up to 8 hours, then at 24, 48, and 72 hours, and then weekly up to 3 weeks. Ketac Endo and Kerr Tubliseal, were the fastest sealers to set in aerobic environments. Ketac Endo and Resilon were the fastest sealers to set in anaerobic environments. Roth 801 and Roth 811 were the slowest sealers to set, taking over 3 weeks to set in either anaerobic or aerobic environments. Resilon sealer set in 30 minutes in both anaerobic environments. However, in the presence of air, Resilon took a week to set and when placed in PBS, an uncured layer remained on the surface.

The aim of this study was to compare coronal microleakage in two conditions. Twenty-eight extracted upper molars were endodontically treated and divided into two groups and controls: group A: prefabricated post and core permanently cemented; and group B: prepared for a post and restored with a temporary post crown cemented with a temporary cement. The teeth were thermocycled, immersed in black India ink for 1 week, and made transparent. Results indicated that the permanently cemented, prefabricated post and core produced the best seal (p < 0.01); leakage was significantly greater with the temporary post crown and was similar to that of a positive control group.

The purpose of this study was to compare the regional bond strengths of C&B Metabond resin to root canal dentin, with or without treatment using a eugenol-containing endodontic sealer liquid. Eighteen extracted human canines were decoronated at the cementoenamel junction with a slow speed saw. The apical third of the root was removed leaving the cervical and middle dentin. The canal space was then enlarged with files, Gates-Glidden burs, and parapost drills. The teeth were ground on either the mesial or distal sides, permitting direct access to the entire canal. The cervical or middle third dentin was treated with Kerr Root Canal Sealer liquid, alternating between the middle and cervical thirds. Each tooth served as its own control. The adhesive resin was then luted directly to the prepared canal. Specimens, 1 x 1 x 8 mm, were prepared and mounted to a Vitrodyne testing machine enabling microtensile bond strengths to be measured. Data were analyzed using a two-way ANOVA and the least squares means test. The mean microtensile bond strengths for the cervical and middle third dentin treated with eugenol were 13.6 +/- 6.1 MPa (n = 33) and 14.8 +/- 3.9 MPa (n = 29), respectively. Without the eugenol, the mean bond strengths were 18.1 +/- 6.0 MPa (n = 31) and 17.3 +/- 4.6 MPa (n = 31) for the cervical and middle sections. The specimens treated with the eugenol liquid had significantly lower bond strengths than those without eugenol (p < 0.05) only in the cervical third. The region of the tooth tested had no effect on bond strength. That is, bond strength of the cervical third was not significantly different from bond strength on the middle third in either of the two groups (with or without eugenol) tested.

The formaldehyde release from three different ground root canal sealer materials was examined. Ten specimens each of AH26, Amubarut, and N2 were stored under dry conditions for 6 months. An amount of approximately 100 to 200 mg ground material was obtained from each sample by using a round bur and stored for 10 min in distilled water. The formaldehyde concentration of the immersion water was determined by high-performance liquid chromatography. The mean formaldehyde release per mg material was 6.6 (+/-2.5) microg for AH26 and 8.3 (+/-1.0) microg for Amubarut. A lower formaldehyde release was detectable by our method from the N2 samples (0.3 +/- 0.1 microg/g; p < 0.0001). In conclusion formaldehyde release from ground root canal material is low, although a risk of an allergic reaction in susceptible patients cannot be excluded.

The antimicrobial activity of four root canal sealers (AH Plus, Sealapex, Ketac Endo, and Fill Canal), two calcium hydroxide pastes (Calen and Calasept), and a zinc oxide paste was evaluated. Seven bacterial strains were used, six of them standard; Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 25922, and Enterococcus faecalis ATCC 10541. There was a wild strain of Streptococcus mutans isolated from saliva obtained in an adult dental clinic. Activity was evaluated using the agar diffusion method with Brain Heart Infusion agar and Müller Hinton medium seeded by pour plate. Calcium hydroxide-based sealers and pastes were either placed directly into 4.0 x 4.0 mm wells or by using absorbent paper points. The plates were kept at room temperature for 2 hr for diffusion. After incubation at 37 degrees C for 24 hr, the medium was optimized with 0.05 g% TTC gel and inhibition haloes were measured. All bacterial strains were inhibited by all materials using the well method. However, when the materials were applied with absorbent paper points, Enterococcus faecalis was not inhibited by zinc oxide, and Pseudomonas aeruginosa was not inhibited by AH Plus, Fill Canal, and the zinc oxide-based paste. We conclude that sealers and pastes presented antimicrobial activity in vitro and culture medium optimization with 0.05 g% TTC gel facilitated observation of the inhibition haloes.

This study examined the effect of three sealers and four irrigants on retention of Dentatus preformed posts luted with Panavia 21 resin cement. Gutta-percha with one of the following sealers--EWT, AH26, Nogenol, or no sealer (control)--was used to fill the root canals of 160 autoclaved incisor and premolar tooth roots. After 72 hr 8 mm post spaces were created with Dentatus Probos Pathfinders and Dentatus reamers. After irrigating the post spaces with saline, 5.25% NaOCl, 50% citric acid followed by NaOCl, or 40% H3PO4, followed by NaOCl, Panavia 21 TC cement was introduced into the canal on the Dentatus #4 stainless steel post's threads. An up-and-down and counterclockwise motion and then a forward twist seated the posts without engaging dentin. Mesiodistal and faciolingual radiographs visualized the chambers. After 72 hr posts were removed axially with an Instron at 5 mm/min. Surprisingly, using Nogenol sealer reduced post retention whereas EWT and AH26 increased retention compared with no sealer. Post retention improved after acid etchants, especially for AH26.

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.

Resin cements are sometimes recommended to enhance the retention of posts in endodontically treated teeth. Many sealer cements used in endodontics contain eugenol, however, which has been shown to inhibit the polymerization of resins. The purpose of this study was to evaluate the effects of a eugenol and a noneugenol sealer cement on the retention of posts. Sixty extracted canines were divided equally into four groups. Each tooth received conventional endodontic therapy and was prepared to receive a post. Two sealer cements were used in obturation: one contained eugenol and one was eugenol-free. The posts were cemented with either zinc phosphate cement or resin cement. Each combination of sealer and post cement was tested for retention on an Instron testing machine. The type of sealer used had no effect on post retention with either cement. Post retention was significantly greater with the zinc phosphate cement than the resin cement.

When a ZnOE type sealer was placed in root canals treated previously with calcium hydroxide dressing, an accelerated sealer setting rate occasionally occurred. This clinical observation led to the present experimental design aiming to investigate the effect of calcium hydroxide on a ZnOE cement and ZnOE type sealers and to preliminarily assess the removal efficiency of a calcium hydroxide preparation from root canal systems. Micro-MIR FTIR spectroscopy was used to quantify the effect of calcium hydroxide on the setting reactions of a ZnOE cement and two ZnOE type sealers. The removal efficiency of calcium hydroxide from root canal systems was evaluated after treatment with NaOCl; NaOCl and filing; and NaOCl plus EDTA and filing. Calcium hydroxide preferentially interacted with eugenol inhibiting the ZnO-eugenol chelate formation. The Ca(OH)2-eugenol interaction was rapid, and kinetically dependent, leading to residual eugenol in the set product. The set ZnOE cement and the ZnOE type sealers in contact with calcium hydroxide were brittle in consistency and granular in structure. Although none of the treatments tested completely removed calcium hydroxide from root canals, treatment with EDTA significantly reduced the extent of residual calcium hydroxide.

Setting times were determined for Kerr pulp canal sealer and the powder component of Kerr pulp canal sealer mixed with different liquid essential oils. The mean setting time of Kerr pulp canal sealer was 16.5 min. The mean setting times for the powder component of Kerr pulp canal sealer mixed with pure eugenol or for the standard liquid component of Kerr pulp canal sealer with rectified turpentine oil were 16.5 and 18.0 min, respectively. There was no significant difference in setting times among the three groups. The addition of rectified turpentine oil to the liquid component of Kerr pulp canal sealer did not have a significant effect on setting time.