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At least 19 recordsLinked to original sources

The effect of root resection on the sealing property of root canal obturations.

Root canal systems of extracted anterior teeth were obturated with sealer and either multiple gutta-percha cones or single silver cones. The effect of root resection on the sealing property of these obturating materials was evaluated by autoradiographic methods. Results indicate that root resection with a rotary instrument in a high-speed handpiece does not adversely affect the sealing property of well-condensed gutta-percha-sealer obturations.

Apicoectomy↗

An in vitro evaluation of coronal microleakage in obturated root canals without coronal restorations.

A study was conducted to evaluate coronal microleakage of Super EBA and Ketac-Endo when used as sealers with single-cone gutta-percha (GP) root canal obturation. The root canals of 24 extracted human teeth were instrumented with flared preparations to a minimum #40 master apical file size. Ten teeth were obturated with a single GP cone and Super EBA as the sealer and ten teeth were obturated with a single GP cone and Ketac-Endo as the sealer. Four teeth were used as controls. Salivary bacterial microleakage studies were conducted to determine whether these sealers could prevent coronal microleakage through the root canal in the absence of a coronal tooth restoration. There was no bacterial penetration through the apical foramen for either sealer tested during the 60-day test period.

Dental Leakage↗

Area-metric analysis of dye leakage for evaluation of sealing ability of root canal obturation techniques.

Root canal sealing ability of obturation techniques has been assessed in vitro with various methods. The majority of the methods employ microleakage tracers and particularly dyes. In vitro measurements of dye penetration are either linear or volumetric. Area-metric analysis is a three dimensional registration method of dye leakage. The purpose of the present study was to evaluate in cleared teeth area-metric analysis as opposed to linear analysis of dye penetration. Forty freshly extracted single rooted human teeth were used. Instrumentation was carried out using Hedstroem files with a step back technique. The root canals were obturated using Roth sealer and qutta-percha cones and lateral condensation technique. The roots were then subjected to dye leakage tests under vacuum of 50 mmHg for 20 min. India ink was used as the tracer. The roots were randomly divided in two groups. In Group A the roots were cleared and linear measurements of the dye penetration were recorded The roots in Group B were ground stepwise transversally and subjected to area metric analysis. The results showed that area-metric analysis enabled sufficient recordings of the dye leakage patterns and the volume of the dye penetration could also be calculated.

Coloring Agents↗

Human saliva penetration of coronally unsealed obturated root canals.

Studies have shown significant coronal dye and bacterial leakage following exposure of sealed root canals to artificial and natural saliva. The purpose of this study was to determine the time needed for bacteria in natural saliva to contaminate the entire length of root canals obturated by lateral and vertical condensation techniques. Forty root canals were cleaned and shaped using a step-back technique. Thirty root canals were obturated with gutta-percha and root canal sealer using either lateral or vertical condensation techniques. Forty root canals were obturated without a root canal sealer and served as positive controls. After obturation, the coronal 3 mm of five root canals were sealed with sticky wax and served as negative controls. The coronal portions of the filling materials were placed in contact with human saliva and the number of days required for bacteria in saliva to penetrate the entire root canals were determined. No bacterial leakage occurred in the negative control group. Complete bacterial leakage occurred within 2 days in the positive control group. All root canals were recontaminated in less than 30 days. No statistical significant difference was found between the two methods of obturation.

Dental Leakage↗

Bacterial leakage in obturated root canals following the use of different intracanal medicaments.

The aim of this study was to examine whether intracanal medication prior to root canal obturation has an inhibitory effect on corono-apical penetration of bacteria. 93 single rooted teeth were instrumented and sterilized with ethylene oxide. They were assigned to three control groups and four test groups with n = 20 each. For one week, they were dressed with different medicaments: The first group with a 5% chlorhexidine gel, the second with Ledermix, the third with a fresh mix of calcium hydroxide and water and the fourth without any medication. After obturation (lateral condensation, AH26) the roots were fixed between a top and a bottom chamber. The top chamber contained 3 mL trypticase soy broth with 10(8) Staphylococcus epidermidis CFU's/mL, whereas the bottom chamber contained sterile trypticase soy broth. For one year, the mounts were incubated at 37 degrees C. They were checked on a regular basis for turbidity in their bottom chambers indicating bacterial growth. None of the test samples leaked for three months. After one year, the calcium hydroxide group had only 6 leaking samples whereas the chlorhexidine group had 14, the Ledermix group 15, and the unmedicated group had 13 leaking samples. It may be concluded that under the conditions of this study, calcium hydroxide was the medicament of choice to avoid bacterial penetration of the root canal. Ledermix did not perform better than no premedication. Chlorhexidine was superior to Ledermix in the second third of the observation period.

Anti-Bacterial Agents↗

In vitro radiographic representation of the extent of voids within obturated root canals.

The aim of this study was to determine whether radiographs provide an accurate representation of the degree of root canal obturation following a cold lateral condensation technique. A total of 40 extracted single-rooted lower premolar teeth were prepared using either a standardized step-back technique or an ultrasonic device by one of two operators. The four groups each of 10 teeth were obturated using lateral condensation by a third operator. To assess apical leakage the obturated teeth were coated with nail varnish to within 2 mm of the apex and immersed in methylene blue for 48 h. The teeth were then radiographed in bucco-lingual and mesio-distal planes prior to subsequent sectioning in a bucco-lingual plane. Sections and radiographs were analysed using an image analysis apparatus to determine the proportion of root canal occupied by gutta-percha, void and/or sealer. Mean percentages of void calculated from the bucco-lingual radiographs, mesiodistal radiographs and tooth sections were 4.14%, 5.98% and 4.98%, respectively. Statistical analysis showed no significant differences between the radiographic views and the tooth sections (P > 0.05). Both planes of radiograph accurately represented the proportion of void when compared with the tooth section.

Analysis of Variance↗

Effect of apical resections and reverse fillings on Thermafil root canal obturations.

This in vitro dye leakage study examined the influence of apical root resection and reverse amalgam fillings on the apical seal of root canals obturated with Thermafil. Fifty human canine teeth were instrumented and obturated with either laterally condensed gutta-percha or Thermafil using Roth's zinc oxide-eugenol Type I regular sealer. After 24 h, one of the following additional procedures was performed on 30 of the teeth: 2-mm apical resection, 4-mm apical resection, and 2-mm apical resection plus reverse amalgam filling 2 mm in depth and diameter. The external root surfaces were coated with enamel paint and the teeth were exposed to 1% methylene blue dye at 37 degrees C for 2 wk. The roots were split longitudinally and the depth of linear dye penetration was measured through a stereozoom microscope. Statistical analysis showed no significant differences in the linear dye penetration among the various groups of teeth.

Analysis of Variance↗

Intraorifice sealing of gutta-percha obturated root canals to prevent coronal microleakage.

A study was conducted to evaluate Cavit, Intermediate Restorative Material, and Super-EBA as intraorifice filling materials to prevent coronal microleakage. Root canal instrumentation and obturation was done on 74 extracted single-rooted teeth. Three and one-half millimeters of the gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the three filling materials. The teeth were suspended in scintillation vials containing trypticase soy broth, and human saliva was added to the pulp chambers. Microbial penetration was detected as an increase in turbidity of the broth corresponding to bacterial growth. At the end of 90 days, the results showed that 15% of the Cavit-filled orifices leaked, whereas 35% of the Intermediate Restorative Material and Super-EBA-filled orifices leaked. The gutta-percha obturated root canals that received an intraorifice filling material leaked significantly less than the obturated, unsealed control group--all of which leaked in < 49 days.

Calcium Sulfate↗

Effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals: an electrochemical study.

AIM: The purpose of this laboratory study was to evaluate the effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals using an electrochemical method. METHODOLOGY: Forty extracted single-rooted teeth were selected and the anatomic crown of each tooth was removed. The specimens were randomly divided into four groups. In group 1, the root canals were prepared with K-files and irradiated with Nd:YAG laser (5 W, 20 Hz) via a 300 microns optical fibre. Then the root canals were obturated with laterally condensed gutta-percha and Pulp Canal Sealer EWT. In group 2, the root canals were treated with the same method as those of group 1 but without laser irradiation. In group 3, the root canals were prepared with ProFiles, laser irradiated and then obturated with vertically condensed gutta-percha and Pulp Canal Sealer EWT. In group 4, the root canals were treated with the same method as those of group 3 but without laser irradiation. The electric resistance between standard and experimental electrodes in the canals was measured over a period of 10 days. RESULTS: At 2 h, groups 1 and 3 irradiated with laser had significantly less apical leakage than group 2 (P < 0.05). After 10 days, group 4 had the highest leakage, followed by groups 2, 1 and 3; the differences between the groups was statistically significant (P < 0.05). CONCLUSIONS: Laser irradiation following root canal preparation reduced apical leakage following root canal obturation.

Aluminum Silicates↗

Apical microleakage of radiolabeled lysozyme over time in three techniques of root canal obturation.

The three methods of obturation assessed in this study were lateral condensation (80 teeth), Thermafil (40 teeth), and McSpadden (40 teeth). All teeth were prepared to the master apical file 30 and widened coronally by Gates Glidden burs before being randomly assigned to experimental groups to be filled by each technique; they were then sealed with nail polish, except for the apical 1 mm. Quantitative evaluation of apical microleakage for each technique was obtained after periods of 1 day, 7 days, 14 days, and 28 days of immersion in a lysozyme solution labeled with radioactive iodine by preparing horizontal sections of the teeth and measuring the level of radioactivity in each section using a gamma counter. Initial (1-day) leakage was least in the Thermafil group and was significantly different from the other techniques. Leakage was greatest in the laterally condensed samples. By the end of the study (28th day) values for lateral condensation were lowest, but were significantly different only for the McSpadden group. For all techniques leakage was most significant in the first 3 mm from the apex and was very low below this level so that all methods can be considered as giving a hermetic seal below 3 mm.

Analysis of Variance↗

Human saliva coronal microleakage in obturated root canals: an in vitro study.

This study assessed salivary penetration through obturated root canals as related to time by using two methods of analysis--histological examination and dye penetrations. A total of 160 human maxillary anterior teeth were instrumented to size 60 Hedstrom file. Ten of the teeth were not obturated; 150 teeth were obturated by lateral condensation of gutta-percha and Roth's root canal sealer. Fifty of these teeth received intermediate restorative material temporaries to a thickness of approximately 3 mm. All teeth were immersed in 50 ml of whole human saliva and kept at 37 degrees C and 100% humidity. The saliva was changed daily. At 2, 7, 14, 28, and 90 days, 32 teeth were removed from the saliva. Of these, two were unobturated and were examined for bacterial penetration by culturing of the apical one-third. Ten teeth without temporaries were immersed in Pelikan ink for 2 days to demonstrate the extent of salivary penetration. These teeth were decalcified and cleared to allow direct measurement of dye penetration. Decalcified serial 7-microns-thick sections were prepared from the remaining 20 teeth, 10 with and 10 without intermediate restorative material temporaries. The sections were stained with hematoxylin and eosin stain and Brown and Hopps stain. Saliva penetration assessed in histological sections was significantly less than was visualized with dye analysis. Salivary penetration at 3 months was significantly greater than at the four earlier study periods. This amount of salivary penetration was considered to be clinically significant. The results strongly suggest retreatment of obturated root canals that have been exposed to the oral cavity for at least 3 months.

Analysis of Variance↗