Obturation Methods Research Articles

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.

Evaluation of apical seal in straight canals after obturation using the lightspeed sectional method

This study evaluated the sectional gutta-percha obturation technique advocated by Lightspeed Technology, Inc. Single relatively straight-canaled teeth were prepared with rotary instruments and divided into three groups. Groups A and B served as controls and were obturated using laterally condensed gutta-percha and either Roth's 801 or Ketac-Endo sealer. Group C was obturated using the Lightspeed technique that included placement of a 5-mm apical section of gutta-percha, followed by backfill with Ketac-Endo sealer and a single gutta-percha cone. All teeth were suspended in India ink for 14 days then cleared. Four additional teeth, which were obturated as in group C then sectioned, revealed a tightly adapted apical section of gutta-percha with a very thin layer of sealer. However, voids were noted in the middle and coronal areas. There was no significant difference in apical microleakage among the three groups. The sectional method was significantly faster than lateral condensation and seems to offer promise as an effective obturation method.

A method of adapting gutta-percha master cones for obturation of open apex cases using heat.

CLINICAL TECHNIQUE: It is generally accepted that the success of root-canal treatment is mainly dependent on the proper cleaning, shaping and hermetic obturation of root canals. Obturation of the root canal is of importance as 60% of endodontic failures are attributable to incomplete obliteration of the root-canal system. The clinical application of many obturation techniques used today demands the preservation of the natural apical construction or the preparation of an artificial equivalent during chemo-mechanical preparation. However, in clinical practice there are cases where the apical foramen is wide because of over-instrumentation, root-end resection during periradicular surgery, root resorption or because the apex of the root is incompletely formed. Thus the preparation of an artificial apical stop is very difficult to achieve. It is a common experience that performing usual gutta-percha condensation techniques in such canals often results in overfilling and therefore special obturation techniques are needed. Some clinical cases of teeth with wide apical foramen treated by a special obturation method are presented in this paper. In this method the end point of the primary gutta-percha cone is elasticized with a heated instrument and inserted into the root canal to record the internal morphology of the apical portion.

Analysis of forces developed during obturations. Wedging effect: Part I

The aim of this study was to define the "wedging effect" created by the intracanal forces developed during obturations and to measure it using a force analyzer device. In endodontics, the wedging effect is the result of, for example, a plugger pushing gutta-percha into a canal: the plugger functions much as the rod of a hydraulic jack and the vertical force applied by this rod induces in the cylinder (i.e. the canal) a hydrostatic pressure that is relatively equal in all directions. It is these forces resulting from the hydrostatic pressure that have been labeled the wedging effect. The original device, the Endographe, had a monobloc cupule for measuring the external vertical and horizontal forces developed by a practitioner, but it was unable to measure the intracanal forces. With a new cupule composed of two independent parts joined under pressure, the wedging effect was recorded and analyzed. Two obturation methods, warm vertical compaction and lateral condensation, were performed by endodontists. The forces were depicted by Endogrammes as a function of time. For all of the forces developed during the two techniques, the mean values showed a nonsignificant difference between the different practitioners. The use of graphs provides a new approach to the analysis of intracanal forces as they develop our time and permits the comparison of different obturation techniques.

Analysis of forces developed during obturations. Comparison of three gutta-percha techniques

The aim of this study was to compare the forces developed during three obturation techniques: warm vertical compaction (WVC), lateral condensation (LC), and thermomechanical compaction (TMC). A force-analyzer device allowed us to record and analyze the forces exerted during the obturations. The different methods, which varied in instrumentation, duration, and compaction load, were studied from graphs representing the force application sequences. In addition, the graphs resulting from specific modifications in the LC technique (use of a single spreader) and deliberately induced failures with TMC (with a too-small condensor or with excessive load) were analyzed. The mean values for the vertical forces for WVC, LC, and TMC were, respectively, 2.5 +/- 0.4 kg, 1.1 +/- 0.3 kg, and 1.65 +/- 0.2 kg. The mean values for the lateral forces were, respectively, 0.85 +/- 0.2 kg, 0.35 +/- 0.1 kg, and 0.5 +/- 0.2 kg. The use of graphs provides a new approach to the analysis of obturation methods and may find its greatest application in the teaching of these techniques. It also has the potential to improve research into obturation technique.

Analysis of the forces developed during obturation: Warm vertical compaction

The aim of this work was to measure and analyze the forces applied by endodontists during an obturation. This was achieved by devising a system of force transducers linked to acquisition software. The software allowed us to study the obturation forces in real time or to store them. In this initial study, the forces developed by endodontists and students during a warm vertical compaction were analyzed. The vertical and frontware backware horizontal direction forces were first stored. Graphs of the compaction forces were then generated, permitting the analysis of the obturation method. Indeed, two cases of obturation failure were analyzed from these graphs. The mean values for the vertical forces applied by the endodontists and students were, respectively, 2.5 +/- 0.4 kg and 1.9 +/- 0.9 kg; the mean values for the lateral forces were, respectively, 0.85 +/- 0.2 kg and 1.4 +/- 0.6 kg. This device permits the analysis of compaction forces and may thus be highly useful in obtaining improvements in obturation techniques.

An in vitro evaluation of the sealing ability of super-EBA cement used as a root canal sealer

Forty-six extracted human teeth, 26 maxillary central incisors, and 20 mandibular incisors were instrumented with flared preparations. The maxillary and mandibular incisors were prepared to #50 and #30 master apical file sizes, respectively. Ten maxillary and mandibular teeth were obturated with a single gutta-percha (GP) cone and Super-EBA cement. Ten maxillary and mandibular incisors were obturated with laterally condensed GP and Roth 801 sealer. Six maxillary incisors were used as controls. Apical leakage of India ink was measured using a stereomicroscope after clearing the teeth. Results showed significantly less leakage in the mandibular incisors filled with GP and Super-EBA (p<0.05). There was no significant difference in leakage when comparing the maxillary central incisors (p>0.05). In this in vitro study, root canal obturation with a single GP cone and Super-EBA showed promise as an effective way to eliminate or reduce apical microleakage. Further studies are needed to test the ability to use this obturation method clinically.

A Study on the Root Canal Obturation Method by Ultrafil Using a Vent Provided into Root Canal

A Study on the Root Canal Obturation Method by Ultrafil Using a Vent Provided into Root Canal

Comparison of apical leakage in root canals obturated with various gutta-percha techniques using a dye vacuum tracing method

In this study, residual apical microlumina remaining after obturation with five different gutta-percha obturation methods were traced with an efficient vacuum method. Seventy-nine human maxillary anterior teeth were instrumented and divided into five groups. The groups were obturated with single-cone techniques, lateral condensation, vertical condensation, Thermafil, and Ultrafil techniques. All specimens were immersed in a vacuum flask containing 2% methylene blue dye solution. The air was evacuated with a vacuum pump to an absolute pressure of 75 torr for 30 min. The roots were sectioned longitudinally and the linear extent of dye penetration was measured. Group mean linear dye penetration values were: single-cone technique, 1.55 +/- 0.95 mm; lateral condensation, 2.25 +/- 1.46 mm; vertical condensation, 2.61 +/- 2.61 mm; Thermafil 1.41 +/- 1.16 mm; and Ultrafil 3.51 +/- 4.70 mm. There were no statistically significant differences between the gutta-percha obturation methods. The clinical implications of these findings are discussed.

Influence of smear layer on the coronal leakage of thermafil and laterally condensed gutta-percha root fillings with a glass ionomer sealer

The effect that two methods of root canal obturation, combined with removal of the smear layer, had on coronal leakage was studied in vitro. Single-rooted teeth with mature apices were prepared chemomechanically and divided into two groups of 72 teeth each. One of the groups was treated with 40% citric acid and 2% sodium hypochlorite to remove the smear layer. The teeth were then subdivided and obturated using the glass ionomer sealer, Ketac Endo and either lateral condensation or Thermafil. After storage for 7 days or 4 months, the specimens were evaluated for coronal leakage using Indian ink. After 90 h, each root was split longitudinally and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification. After 7 days, there was significantly less leakage in those teeth obturated with Thermafil without smear layer compared with the other groups (p < 0.05). After 4 months, there was no significant difference in leakage between the groups (p > 0.05).

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.

CONTEMPORARY PERSPECTIVES ON CANAL OBTURATION

The astute practitioner must recognize that no one particular obturation technique will satisfy the myriad of clinical cases that require endodontic therapy. The obturation method selected, whether it be a conventional method or one of the contemporary ones, must be consistent with the overall goals of clinical practice; i.e. to provide the best possible care for our patients. Although all obturation techniques have their advantages as well as their disadvantages, the clinician should be open-minded enough to accept and master a number of obturation techniques and not just focus on one. At the same time, he or she should be able to provide a biologically sound rationale for the method he or she chooses. In time, this philosophy will generate dental practitioners who can not only solve problems but who can also think critically.

Evaluation of apical seal and placement control in straight and curved canals obturated by laterally condensed and thermoplasticized gutta-percha

The sealing ability of laterally condensed gutta-percha was compared with injection-molded thermoplasticized gutta-percha in straight and curved canals. A standardized mix of Roth's sealer was used. After exposure to 2% methylene blue dye for 7 days, the teeth were sectioned at 1.0-mm increments and examined by two independent evaluators. The results indicate no statistically meaningful difference in microleakage between the methods of obturation. The incidence of either an overextension or under-extension of gutta-percha was 20% for lateral condensation and 50% for the injection-molded thermoplasticized technique. The differences were significant for teeth with both straight and curved canals.

A clinical evaluation of four obturation methods for root canals

A clinical evaluation of four obturation methods for root canals

Gutta-percha: a comparative study of three methods of obturation

A comparative study of three commonly used gutta-percha filling techniques—Kloroperka infusion, vertical condensation with warm gutta-percha, and lateral condensation—was undertaken to see which method best replicated the entire prepared root canal system. Models of the root canals were made by dissolving the tooth structure away after the root canals were filled. Kloroperka infusion proved to be superior to warm gutta-percha with vertical condensation and to lateral condensation in replication of morphologic aberrations, uniform sealer dispersement, and homogeneity of filling. All three techniques proved equally satisfactory in density of filling, conformity to the prepared root canal, and conformity to the shape of the apical preparation. It appears that of these three techniques, Kloroperka infusion best replicates the prepared root canal system and its inherent morphologic aberrations. A comparative study of three commonly used gutta-percha filling techniques—Kloroperka infusion, vertical condensation with warm gutta-percha, and lateral condensation—was undertaken to see which method best replicated the entire prepared root canal system. Models of the root canals were made by dissolving the tooth structure away after the root canals were filled. Kloroperka infusion proved to be superior to warm gutta-percha with vertical condensation and to lateral condensation in replication of morphologic aberrations, uniform sealer dispersement, and homogeneity of filling. All three techniques proved equally satisfactory in density of filling, conformity to the prepared root canal, and conformity to the shape of the apical preparation. It appears that of these three techniques, Kloroperka infusion best replicates the prepared root canal system and its inherent morphologic aberrations.

Molar Endodontics

The terminal objective of all endodontic techniques is to eliminate the root canal system and its affected tissue as an instigator of periradicular inflammation and infection. The therapeutic regimen includes eradication of bacteria and tissue debris from the root canals and a three-dimensional obturation of the space with a dense, dimensionally stable and tissue tolerated filling. The most common methods of canal obturation have been described. Specific omissions of other filling techniques (vertical condensation with warm gutta percha, chloropercha technique, or Johnson-Callahan method) is in no way intended to discount or minimize their efficacious results. However, these techniques are sufficiently detailed as to warrant a separate discussion. The reader is referred to other inclusions in this symposium for a more comprehensive view of adjunctive therapies related to molar endodontics.