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Adaptation and placement of alpha-phase gutta-percha delivered with a plastic core-carrier, Thermafil, was compared to the lateral condensation of gutta-percha in a specific tooth model. Fifty-one mandibular molar roots with separate canals, patent canal orifices and curvatures greater than 15 degrees were cleaned and shaped with K-files and 2.5% sodium hypochlorite to a size 30 at the apex, and flared with Hedstrom files to create a continuously tapering funnel preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha-phase gutta-percha on a plastic Thermafil carrier, or standard beta-phase gutta-percha with lateral condensation. Roots were radiographed from the proximal and evaluated by three examiners, based on established criteria for overall material adaptation, apical adaptation, and filling material extrusion. Thermafil provided a statistically significant better overall canal obturation (P < 0.001), while, in the apical third, both techniques were not significantly different (P > 0.05). When the apical orifice was patent there was a significant propensity for the extrusion of filling materials beyond the apex (P < 0.001) with the Thermafil technique.

The short- and long-term apical seal of root canals obturated with softened alpha-phase gutta-percha on plastic core-carriers, Thermafil, was compared to that of laterally condensed, cold gutta-percha. Fifty-one roots from mandibular molars with separate canals, patent canal orifices and curvatures greater than 15 degrees were cleaned and shaped with K-files and 2.5% sodium hypochlorite to a size 30 at the apex, and flared with Hedstrom files to create a continuously tapering funnel preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha-phase gutta-percha on a plastic Thermafil carrier, or standard beta-phase gutta-percha with lateral condensation. Teeth were separated into three groups of 17 each and placed in black India ink for 24 h, 7 days or after 5 months storage in water. The teeth were demineralized, rendered transparent, and apical microleakage determined by the linear measurement of dye penetration. Significant differences in microleakage were noted between the 24 h and 5-month Thermafil groups (P < 0.05), 24-h and 7-day lateral condensation groups (P < 0.05), and 24-h and 5-month lateral condensation groups (P < 0.05). There were no significant differences between the two techniques at each time interval. It was concluded that both techniques demonstrated a significant increase in apical microleakage over a 5-month period.

Temperature elevations of 10 degrees C above body temperature, of duration greater than 1 minute, may be sufficient to cause bone tissue injury. Temperature rises on the root surface in excess of 10 degrees C have been shown in studies in vitro of thermoplasticized gutta-percha root filling techniques. To determine whether results in vitro at room temperature could be extrapolated to conditions in vivo, temperature elevations were recorded at the mid-point on the root surface of the canine tooth in the ferret during thermomechanical compaction of gutta-percha. The time taken for the temperature to return to normal was also measured. There was no statistically significant difference between temperature elevations recorded in vitro and those measured in vivo. A linear extrapolation may therefore be made from results recorded at room temperature. Temperature elevations dissipated more rapidly in vivo than in vitro; this may be due to the cooling effect of the microvasculature of the periodontal membrane.

An in vivo investigation is described and a histological evaluation made of the effect of canal obturation by thermomechanical compaction of gutta-percha and sealer on the cementum on the lateral surface of the root and adjacent periodontal membrane and alveolar bone of the ferret canine after time intervals of 24 hours, 20 days and 40 days. These tissue reactions were compared with those in the roots of control teeth filled by lateral condensation of cold gutta-percha and sealer. Iatrogenic damage was apparent in a minority of the experimental specimens 20 and 40 days after obturation.

The effect of three methods of root-end preparation. following apical resection, on the apical seal of root-end fillings, was studied in vitro. Root canals of 116 single- rooted teeth with mature apices were prepared chemo-mechanically and obturated with gutta-percha and sealer. The root ends were resected with a diamond but under water coolant and were prepared as follows: group I a size 010 round bur was used to prepare an apical cavity 2-3 mm down the long axis of the root; group H treatment as per group 1 followed by a 60-s rinse with a solution of 10:3 (10% citric acid: 3% Fe2Cl3); and group 111 an ultrasonic retrotip was used to prepare a 2-3 mm deep apical cavity. The root end was restored with an EBA cement. Apical leakage was determined using India ink after 7 days and 7 months. The teeth were demineralized, rendered transparent and linear dye penetration was recorded. Results showed that there was no significant difference in leakage between the groups at each time interval (P>0.05) but there was increased leakage after 7 months (P<0.01). Cracking of the root surface was seen most often with the ultrasonically prepared roots (P<0.001). [ABSTRACT FROM AUTHOR]

The effect on coronal leakage of the use of either a single gutta-percha cone or cold lateral condensation of gutta-percha, with a glass ionomer sealer cement was studied. In addition, the effect of the removal of the smear layer was also determined. Eighty-eight single-rooted teeth were prepared chemomechanically using hand files, with the balanced force technique. Lubrication was provided by either Hibiscrub (maintaining the smear layer) or an EDTA-containing paste (to remove the smear layer). Copious irrigation was carried out with 2.2% sodium hypochlorite. The teeth were allocated randomly to four groups of 20 teeth each, the remaining eight teeth served as controls. Two groups of teeth, one with and one without smear layer, were obturated with either a single gutta-percha cone or cold laterally condensed gutta-percha, with Ketac Endo as the sealer. The teeth were stored for 6 weeks, thermocycled, and the extent of coronal leakage determined for each group after immersion in India ink for 90h. The teeth were demineralized, dehydrated and immersed in methyl salicylate, which rendered them transparent. Linear measurement of maximum dye penetration was recorded. The mean depth (+ SD) of leakage for the groups in which the smear layer was left intact was 1.68mm (+ 0.38) for the single cone (A1) and 2.29 mm (+ 1.58) for lateral condensation (B1). When the smear layer was removed the mean depth of leakage for the single cone group (A2) was 2.04 mm (+ 0.73) and 2.37mm (+ 1.70) for the laterally condensed group (B2). There was no significant difference in coronal leakage between the groups (P>0.05). [ABSTRACT FROM AUTHOR]

The effect of post space preparation on the apical seal of teeth roots treated with the plastic-cored Thermafil was studied in vitro. Single rooted teeth with mature apices were prepared chemomechanically and obturated with alpha-phase gutta-percha, Thermafil, on plastic core-carriers and sealer, Scalapex. The teeth were divided randomly into four groups of 18 teeth each. In two of the groups post space was prepared by hand using a Parapost drill (diam. 1.25 mm) after gutta-percha removal with Peeso reamers in a slow-speed handpiece, one group immediately after canal obturation and the other after storage in 100% relative humidity at 37°C for 1 week; 5 mm of root filling was left intact. The time taken to remove the gutta-percha was recorded. Post space was not prepared in the control groups. Apical leakage was determined using black India ink. The teeth were demineralized, rendered transparent, and linear measurement of dye penetration was recorded. Results showed that there were no significant differences in leakage between any of the groups (P>0.05). There was no statistically significant difference in the time required to remove the gutta-percha from the root canals in both groups (P<0.05). It is concluded that under the conditions of this study post space preparation immediately after obturation, or after a delay of 1 week, does not affect the apical seal of Thermafil with plastic core-carriers. [ABSTRACT FROM AUTHOR]

The effect of the removal of the smear layer on coronal leakage of root fillings was studied using two sealer cements. Sixty single-rooted teeth with mature apices were prepared chemomechanically using a modified double-flared technique with non-cutting tipped files and copious irrigation with 2% sodium hypochlorite. The teeth were randomly allocated to four groups of 15 teeth each. Two groups were treated with 40% citric acid to remove the smear layer. Two groups of teeth, one with and one without smear layer, were filled by lateral condensation of gutta-percha with either Tubliseal or a resin-based glass ionomer, Vitrebond. The teeth were stored for 1 week, thermocycled, and the extent of coronal leakage determined for each group after immersion in indian ink for 90 h. The teeth were demineralized, dehydrated and immersed in methyl salicylate which rendered them transparent. Linear measurement of dye penetration was recorded. The mean depth (± SD) of leakage for the groups in which the smear layer was left intact was 4.26±1.53 mm and 6.83±1.65 mm for the Vitrebond and Tubliseal, respectively. When the smear layer had been removed, the mean depth of Leakage for the Vitrebond group was 1.13±0.29 mm, and 3.72±1.23 mm for the Tubliseal group. There was a statistically significant difference in leakage between the groups (P<0.001). With both sealers, those teeth in which the smear layer had been removed showed less leakage than the specimens in which the smear layer was left intact (P<0.001). The Vitrebond specimens leaked less than the teeth that were root filled using Tubliseal, both when the smear layer was intact and when It was absent (P<0.001). [ABSTRACT FROM AUTHOR]

Temperature elevations of 10°C above body temperature, of duration >1 minute, may be sufficient to cause bone tissue injury. Temperature rises on the root surface in excess of 10°C have been shown in studies in vitro of thermoplasticized gutta-percha root filling techniques. To determine whether results in vitro at room temperature could be extrapolated to conditions in vivo, temperature elevations were recorded at the mid-point on the root surface of the canine tooth in the ferret during thermomechanical compaction of gutta-percha. The time taken for the temperature to return to normal was also measured. There was no statistically significant difference between temperature elevations recorded in vitro and chose measured in vivo. A linear extrapolation may therefore be made from results recorded at room temperature. Temperature elevations dissipated more rapidly in vivo than in vitro; this may be due to the cooling effect of the microvasculature of the periodontal membrane. [ABSTRACT FROM AUTHOR]

An in vivo investigation is described and a histological evaluation made of the effect of canal obturation by thermomechanical compaction of gutta-percha and sealer on the cementum on the lateral surface of the root and adjacent periodontal membrane and alveolar bone of the ferret canine after time intervals of 24 hours, 20 days and 40 days. These tissue reactions were compared with those in the roots of control teeth filled by lateral condensation of cold gutta-percha and sealer. Iatrogenic damage was apparent in a minority of the experimental specimens 20 and 40 days after obturation. [ABSTRACT FROM AUTHOR]

The leakage associated with restorative materials placed within the pulp chamber of maxillary and mandibular molars was studied in vitro. The root canals and pulp chambers of 69 extracted teeth were prepared chemomechanically and sealed with gutta-percha and Tubliseal using cold lateral condensation. The teeth were divided into five groups. Gutta-percha was removed from the pulp chambers of three of the groups of 15 teeth and filled with one of three materials, a glass ionomer cement, a cement or an amalgam. The gutta-percha was removed from the pulp chamber in the fourth group of nine teeth, which were left unfilled. The gutta-percha in the pulp chambers of the fifth group of teeth was left intact. The teeth were suspended in Indian ink, thermocyded for 24 hours and stored for a further 48 hours at 37°C. They were then demineralized and cleared and the degree of coronal leakage was assessed. Those teeth with no filling in the pulp chamber showed extensive leakage. The gutta-percha-filled group demonstrated rearer leakage than did the groups in which other restorative materials had been employed (P<0.01). No significant differences in leakage occurred between the other groups (P0.05). It is recommended that the pulp chamber of molars should be restored with a filling material following root canal treatment. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to assess the effect of compactor design, alterations in rotational speed and modification to the basic technique of thermomechanical compaction on the quality of the apical seal produced by gutta-percha and sealer cement. The integrity of the apical seal achieved using two different configurations of compactor, rotational speeds of 8000 and 16,000 rev/ minute and a hybrid technique which combined thermomechanical compaction with lateral condensation were compared with conventional lateral condensation. The same brand of gutta-percha and type of sealer were used throughout the investigation. A cleared tooth technique that allowed the three- dimensional assessment of Indian ink leakage was employed. Instrument fracture, a problem experienced in some other investigations, did not occur with either design of compactor used. Apical dye leakage was found to be a relatively frequent occurrence with each variation in obturation technique studied, including that of lateral condensation of cold gutta-percha and sealer. The results showed no significant difference in the mean degree of leakage for each of the groups or in the proportion of specimens that showed leakage (P>0.1). The advantages of the hybrid method of root canal obturation were discussed. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess long-term coronal leakage in root fillings achieved by 2 gutta-percha techniques using 2 calcium hydroxide-containing sealers. The root canals of 90 single-rooted teeth with mature apices were prepared chemomechanically. The teeth were placed randomly into four experimental groups (n = 20) and obturated with either lateral condensation of cold gutta-percha or a thermo-plasticized gutta-percha delivery, system, JS Quickfill, using Sealapex or Apexit as the sealer. A further five teeth were placed in each of negative or positive control groups. After root filling the teeth were sectioned at the cernentoenamel junction and stored in saline solution at 37° for 1 yr. Coronal leakage was then determined with an India ink tracer (using a reduced pressure model) and a clearing technique. The extent of coronal leakage was measured at ×6 magnification. Non-parametric analysis showed that there was significantly more leakage with the thermally softened gutta-percha technique than with lateral condensation (p<0.05). There was no significant difference in leakage between the groups obturated with lateral condensation (p>0.005) but, with the thermoplasticized technique, there was more leakage ,with the sealer Sealapex (p<0.05). [ABSTRACT FROM AUTHOR]