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At least 181 records · Page 10Linked to original sources
PubMed1991

The effect of post space preparation on the apical seal of root canal obturated teeth.

The dental literature is contradictory about the quality of the apical seal as it relates to the length of remaining gutta-percha following post-space preparation. The purpose of this study was to compare apical leakage with varying remaining lengths of gutta-percha in an in vitro system. Fifty disarticulated single canal human mandibular premolar teeth were used in five experimental groups. All root canals were prepared 1 mm short of the apical foramen through a size 50 k-file and sequentially flared through a size 70 k-file. Four groups were obturated using gutta-percha with lateral condensation and Roth's 801 Elite Grade root canal sealer. Post-space preparation was accomplished by removing gutta-percha with heated pluggers so that the lengths of the remaining filling varied by increments of one millimeter between 3 and 7 mm. Specimens were covered with enamel paint leaving only the apical foramen exposed. All roots were then submerged in 1 percent methylene blue dye for two weeks, sectioned longitudinally, and measured for depth of dye penetration. No significant difference was found between the 4 and 5 mm groups or between the 6 and 7 mm groups. Significant difference (p less than .05) in leakage did exist between the 3, 4-5, and 6-7 mm groups, showing the least in the latter groups. The best apical seal was obtained when the maximum of 6 mm of gutta-percha remained.

Analysis of Variance↗
PubMed1999

Immediate core buildup of endodontically treated teeth: the rest of the seal.

One primary objective of endodontic therapy is to establish an adequate seal with the root canal filling material. The placement of an immediate amalgam buildup at obturation, in conjunction with rubber dam isolation, allows an endodontic seal to be extended from the foramen to the cavosurface margin. As a result of this immediate buildup, the length of the seal and the longevity of the endodontic treatment are presumably extended. This article describes an effective means of performing the immediate core buildup of endodontically treated teeth.

Dental Amalgam↗
PubMed2003

Bacterial penetration through canals of endodontically treated teeth in the presence or absence of the smear layer.

OBJECTIVES: The goal of this study is to determine if the smear layer affects the passage of bacteria through or around obturating material as evidenced by penetration of bacteria through and out the canal. Specifically, this study focused on determining the effect of the smear layer on the magnitude of bacterial penetration through the apical foramen. METHODS: Thirty extracted, maxillary central or lateral incisors were collected. Teeth were randomly assigned (10 teeth per group) to three groups: (1) smear layer removed, (2) smear layer present, and (3) negative control. Canal preparation and obturation using lateral condensation, gutta percha, and AH 26 sealer was performed on all of the teeth. Removal of the smear layer was accomplished by rinsing with 17% EDTA. The model systems consisted of an upper chamber attached to the cemento-enamel junction and a lower chamber at the apices of the teeth. Standardized bacterial suspensions containing Fusobacterium nucleatum, Campylobacter rectus, and Peptostreptococcus micros were inoculated into the upper chambers. Models were incubated anaerobically at 37 degrees C. At various times over a 60-day period, samples were taken from the lower chamber and spiral-plated on selective-differential media to determine numbers and types of bacteria. RESULTS: Leakage results were as follows: (1) smear layer present-6/10 leaked; (2) smear layer removed-0/10 leaked; (3) negative control-0/10 leaked. Profiles of bacterial leakage were similar among the groups. F. nucleatum was the predominant microorganism. CONCLUSIONS: This study indicated that removal of the smear layer reduced the leakage of bacteria through the root canal system.

Bismuth↗
PubMed1989

Use of an electronic apex locator in the treatment of teeth with incomplete root formation.

An electronic apex locator was used to determine length and control apical bridge formation in the treatment of teeth with incomplete root formation. Measurements were taken in 10 teeth in which apexification therapy had just started and in 11 teeth where the formation of the apical barrier was considered to be complete. In the beginning of the apexification therapy, when the apical foramen was still open, endometric measurements gave incorrect results in all instances. After apical closure had occurred and definite obturation of the root canal seemed possible, the apex locator in all teeth gave correct results and complete agreement was obtained between the radiographs and the electronic tests. Even in teeth in which complete apical closure could not be obtained, the results of electronic measurements were correct. Electronic apex locators may be used as auxilliary devices in controlling apical hard tissue closure in the treatment of teeth with incomplete root formation.

Adolescent↗
PubMed1998

Apical limit of root canal instrumentation and obturation, part 1. Literature review.

One of the major controversies in root canal therapy concerns the apical limit of instrumentation and obturation. The results of longitudinal prognostic studies, basic anatomical knowledge of the apical third of the root canal, and the histological pulp reaction to caries progression demonstrated the presence of a vital apical pulp remnant, even in the presence of a periapical lesion. Finally necrosis and bacteria establish themselves in the periapical lesion. All valid prognosis studies confirm the practice of staying short of the apex with a homogeneous obturation to obtain the highest success rate of 90-94% (when done by or under supervision of specialists; results in the general population had a failure rate greater than 50%). The location of the apical foramen(ina) related to root canal treatment most frequently ends short of the apex, often by several millimetres.

Dental Pulp↗
PubMed1989

[Making a mernetic root seal].

Sixty permanent human teeth, all with straight, accessible root canals were analyzed in vitro in order to compare the sealing capacity of three different instrumentation and obturating techniques, namely: Obtura system, sonic and ultrasonic techniques, and modified lateral instrumentation and condensation technique. Root canals were instrumented and obturated according to guidelines of each technique. Three layers of varnish were then applied, except on a 1 mm area around the apical foramen. The pieces were immersed in 5% methylene blue, making sure that the apical foramen kept in contact with the solution. Next, they were introduced in an incubator for a 48-hour period, at a temperature of 37 degrees C. Longitudinal sections were subsequently cut and observed on the stereoscopic microscope. Penetration values of the dye in each specimen were obtained by means of a micrometric slide. These were analyzed in a computer by the Student T method, yielding a value of P greater than 0.5, meaning there is no statistical difference in the comparison of the three techniques under study.

Dental Leakage↗
PubMed2003

Analysis of continuous-wave obturation using a single-cone and hybrid technique.

This study analyzed the adaptation of gutta-percha to prepared root canal walls using two obturation techniques and determined the influence of the System-B plugger depth on filling adaptation. Fifty-six extracted human mandibular molars were instrumented using Profile NiTi rotary instruments, stratified based on curvature, then randomly distributed into two groups. Group 1 was obturated using the single-cone continuous-wave technique. Group 2 was obturated with a hybrid technique: lateral condensation followed by a continuous-wave down-pack. Based on System-B plugger penetration, teeth were divided into three subgroups: (a) < 3.5 mm, (b) 3.5 to 4.5 mm, and (c) > 4.5 mm. Roots were horizontally sectioned at 1 mm and 3 mm coronal to the apical foramen, stained, and photographed. Four evaluators scored the adaptation of gutta-percha to the prepared canal walls. In 100% (n = 56) of the samples, no statistically significant difference existed between the two obturation methods at 1-mm (x = 1.80, SD +/- 0.69) or 3-mm (x = 1.804, SD +/- 0.69) sections. Best results were obtained with a plugger depth 3.5 to 4.5 mm from the working length.

Gutta-Percha↗
PubMed1993

An experimental study of the sealing ability of a dentinal apical plug treated with bonding agent.

The purpose of this study was to evaluate the sealing ability of a dentinal apical plug treated with a bonding agent. Ninety human lower premolars were used. The teeth were divided into three groups. in groups 1 and 2, to prepare an apical isthmus of 1 mm in length, the first apical seat was prepared with a #45 K file 1 mm short of the anatomical apex and with a #60 K file 2 mm short for the second apical seat. Dry dentin fillings were packed in the apical isthmus with a #60 K file. In group 1, the root canal was obturated with gutta-percha and Canals root canal sealer by the lateral condensation method. In group 2, following an application of the bonding agent to the plug, the root canal was obturated in the same way. In group 3 (control), a single apical seat was prepared with a #60 K file 1 mm short of the apex and the root canal was obturated similarly. The teeth of three groups were immersed in a 1% methylene blue solution for 1, 2, and 4 wk. Dye penetration depth from the apical foramen was determined. Group 2 showed no leakage after 4 wk. Groups 1 and 3 showed dye penetration into the root canal, and in these two groups dye penetration increased with time.

Composite Resins↗
PubMedDate not supplied

[A morphological basis for the levels of pulp extirpation and root c anal obturation (experimental morphological research)].

Periapical tissue reaction to root canal filling with zinc-eugenol paste (complete or incomplete filling) was studied in 15 teeth of 5 mongrel dogs after total or subtotal pulp extirpation. Inflammatory reaction developed in all the cases. It was more intensive in cases with total extirpation of the pulp followed by complete or incomplete filling of the root canal than after subtotal extirpation of the pulp followed by root canal filling 1-2 mm below the anatomical apical foramen.

Animals↗
PubMed1999

Study on apical leakage of the teeth after argon laser treatment and obturation.

OBJECTIVE: This study was performed to compare the apical leakage degree after laser treatment and obturation with that without laser treatment, and to evaluate the efficiency of argon laser irradiation in removing debris and smear layer from the prepared root canal walls in vitro. SUMMARY BACKGROUND DATA: There has been no report of laser effect on apical leakage after laser treatment and obturation. METHODS: Fifty-six human extracted single root teeth were used in this study. Teeth were divided into four groups of 14 teeth each and prepared up to a #60 K-file size at 1 mm short of the apical foramen using a step-back technique. Argon laser at the wavelength of 470 nm and at the output of 0.3 W was irradiated at apical stop for 1, 2, or 3 seconds at the continuous mode. In each group, ten teeth for the microleakage study were obturated and immersed in rhodamine B solution for 48 hours at 37 degrees C, and the others were used for the observation by scanning electron microscopy (SEM). All teeth were bisected longitudinally and observed by stereoscopy or SEM. RESULTS: The apical leakage degree after laser treatment and obturation was reduced compared to that in the control, but not significantly (p > 0.05). However, debris and smear layer in the laser-treated groups were removed from apical stop even at low energy density. CONCLUSIONS: These results suggest that apical leakage after argon laser treatment is not reduced significantly, but that argon laser is useful for removing debris and smear layer from root canals.

Dental Leakage↗
PubMed1998

Apical limit of root canal instrumentation and obturation, part 2. A histological study.

The results of an in vivo histological study involving apical and periapical tissues following root canal therapy after different observation periods demonstrated the most favourable histological conditions when the instrumentation and obturation remained at or short of the apical constriction. This was the case in the presence of vital or necrotic pulps, also when bacteria had penetrated the foramen and were present in the periapical tissues. When the sealer and/or the gutta-percha was extruded into the periapical tissue, the lateral canals and the apical ramifications, there was always a severe inflammatory reaction including a foreign body reaction despite a clinical absence of pain.

Adolescent↗