Periodontal tissue reactions following root canal obturation with an injection-thermoplasticized gutta-percha technique

Comparative Analysis of Temperature Variation with Three Continuous Wave Obturation Systems in Endodontics: An In Vitro Study

The aim of this study was to assess temperature changes with different continuous wave obturation systems when downpacking to 2 mm and 4 mm from the apical foramen in an open system not simulating the surrounding biological structures at body temperature. Sixty single-rooted teeth were divided into three groups: (A) Dia-Duo® (DiaDent Group International, Cheongju-si, Korea), (B) Elements Free® (Kerr Corporation, Orange, CA, USA) and (C) Calamus® (Dentsply Sirona, Ballaigues, Switzerland). The root canals were instrumented with Protaper Gold (Dentsply Sirona, Ballaigues, Switzerland) to size F2 (25.08). The root canals were filled by a continuous wave using an AH Plus® sealer (Dentsply Sirona). Temperatures during the obturation procedure were measured by a thermal imaging camera (Testo 875-1®) perpendicular to a vice where the teeth were held at −2 mm and −4 mm from the apical foramen. Comparisons were made by applying Student’s t-test and ANOVA (p = 0.05). The continuous wave technique at −2 mm with the Dia-Duo system® emitted average temperatures of 37.3 °C, Elements Free® emitted 39.85 °C and Calamus® emitted 40.16 °C. At −4 mm, the Dia-Duo system® emitted average temperatures of 34.81 °C, Elements Free® emitted 33.73 °C and Calamus® emitted 32.91 °C. There were significant differences between continuous waves at −2 mm and at −4 mm (p < 0.05). Dia-Duo® was the only system that did not present significant differences between the two lengths (p = 0.197). Regarding the heat emitted, the best system was Elements Free®, since, at −2 mm, it emitted the highest temperature without going above 47 °C. The Dia-Duo® system had lower temperatures. It could be concluded that not all systems transmit the same temperature to the apex and, therefore, to the periapical tissues. The surrounding conditions, such as temperature and humidity, have not been considered in this study.

Temperature Changes on External Root Surfaces with the Use of Several Thermoplastic Filling Techniques

INTRODUCTION

The purpose of this study was to measure the temperature rise on the external root surface of filled root canals using Touch'n Heat (Analytic Endodontics, Orange, CA), the TC System (TC; Tanaka de Castro & Minatel Ltda, Cascavel, PR, Brazil), and the Tagger technique.

METHODS

Forty-five single-canal mandibular premolar human teeth were used in the 3 experimental groups. The root canals were enlarged to accommodate up to an R40 Reciproc file (VDW, Munich, Germany). Next, the specimens were filled according to the technique evaluated. The measurement of the temperature was performed by K chromium-aluminum thermocouples attached to the coronal, middle, and apical root levels.

RESULTS

There was a significant difference among the 3 techniques (P < .001) in relation to the temperature variation between the highest temperature and the initial temperature. The highest temperature change was found with the Tagger technique at the middle third root level (11.8°C), and the lowest variation was in TC at the cervical third (2.05°C).

CONCLUSIONS

There was a rise of temperature on the external root surface for all of the techniques evaluated. TC showed the lowest temperature rise.

Thermal irritation of teeth during dental treatment procedures

While it is reasonably well known that certain dental procedures increase the temperature of the tooth's surface, of greater interest is their potential damaging effect on the pulp and tooth-supporting tissues. Previous studies have investigated the responses of the pulp, periodontal ligament, and alveolar bone to thermal irritation and the temperature at which thermal damage is initiated. There are also many in vitro studies that have measured the temperature increase of the pulp and tooth-supporting tissues during restorative and endodontic procedures. This review article provides an overview of studies measuring temperature increases in tooth structures during several restorative and endodontic procedures, and proposes clinical guidelines for reducing potential thermal hazards to the pulp and supporting tissues.

Bone level around endodontically treated teeth in periodontitis patients

OBJECTIVES

This retrospective study compared the marginal bone level of teeth with root canal fillings with contra-lateral teeth without.

METHODS

Of 286 consecutive patients (> or =35 years), referred to practice for periodontology in the Netherlands, 67 full sets of radiographs contained > or =1 endodontically treated tooth and its contra-lateral tooth without root canal treatment. Bone level at the mesial and distal of these teeth was scored from the CEJ. In multi-rooted teeth, the presence of interradicular radiolucency was assessed. The presence of posts, and periapical radiolucencies was assessed. Analysis for differences between treated teeth and contra-laterals was controlled for tooth surface, presence of a post and tooth type.

RESULTS

The mean distance from the root filling to the apex was 2.6 mm. Periapical radiolucencies were found in 14%. The mean bone level was at 4.3 mm for endodontically treated teeth and at 3.7 mm for contra-laterals. Significantly more bone loss (0.6 mm) was found at the endodontically treated teeth. No difference was found between mesial and distal, teeth without and with posts and different tooth types. The presence of interradicular radiolucency was more frequent in endodontically treated teeth (OR 2.1, p(McNemar test)=0.039).

CONCLUSION

In periodontitis patients, teeth with endodontic treatment had more bone loss as compared with untreated contralaterals.

In Vitro Infrared Thermographic Assessment of Root Surface Temperatures Generated by High-Temperature Thermoplasticized Injectable Gutta-Percha Obturation Technique

The aim of this in vitro study was to measure the temperature rises on the outer surface of roots produced by high-temperature thermoplasticized injectable gutta-percha technique. Thirty extracted human teeth with a single canal (15 maxillary central incisors and 15 mandibular central incisors) were used in this study. After root canal cleaning and shaping, the teeth were obturated with the injected gutta-percha heated to 160 degrees C (Obtura II). Temperature changes on the whole mesial outer surface of the roots was measured using an infrared thermal imaging camera. It showed that the use of gutta-percha heated to 160 degrees C to fill the maxillary central incisors and mandibular central incisors resulted in the rises of the root surface temperature by 8.5 degrees C and 22.1 degrees C, respectively. In conclusion, the injection of the gutta-percha heated to 160 degrees C into the root canal of maxillary central incisors produces temperature on the outer root surfaces below the theoretical critical level and, therefore, should not cause damage to supporting periradicular tissues. The injection of gutta-percha into the root canal space of the mandibular central incisors in vitro, resulted in an elevation of the root surface temperature by more than 10 degrees C.

Root surface temperature rises during root canal obturation, in vitro, by the continuous wave of condensation technique using System B HeatSource

OBJECTIVES

This in vitro study evaluated increases in root surface temperature during the continuous wave of condensation technique using a System B HeatSource.

STUDY DESIGN

Forty-five extracted human teeth (15 maxillary central incisors, 15 mandibular central incisors, and 15 maxillary canines) were used. After root canal cleaning and shaping, the teeth were filled with the continuous wave of condensation technique using a System B HeatSource. Temperature changes on the whole mesial and vestibular outer surfaces of the roots were measured using an infrared thermal imaging camera.

RESULTS

The results of this in vitro study showed that the use of the continuous wave of condensation technique to fill the maxillary central incisors and maxillary canines produced temperature rises below the critical level. In the mandibular central incisors the use of a System B HeatSource resulted in elevation of the root surface temperature by more than 10 degrees C.

CONCLUSION

The continuous wave of condensation technique using the System B HeatSource produces temperature changes on the outer root surfaces, which, in the case of teeth with relatively thin dentinal walls, can reach relatively high values.

Clinical and Radiographic Evaluation of Root-canal Obturation with Obtura II

This study evaluated clinical and radiographic healing of 236 root-canal treatments in 131 cases obturated with the Obtura II system. One operator performed all canal preparation and obturation with sealer. A standardized apical-coronal preparation technique instrumented all canals. Clinical symptoms, periodontal condition, and radiographic findings were evaluated at 3, 6, and 12 months. Radiographs taken immediately postobturation were compared to recall radiographs. The level of the final root filling was classified as short (more than 2 mm short of the apex), flush (within 2 mm), or over (beyond) in 12.7%, 81.4%, and 5.9% of cases, respectively. More than 96% of cases were treated successfully by the Obtura II system. Where roots were filled flush, over, or short, lesions healed in 97%, 93%, and 93% of cases, respectively, with no significant differences (p < 0.05). Root filling excess had no impact on the healing process.

Heat transfer to the periodontal ligament during root obturation procedures using an in vitro model

It appears to be important to avoid thermal injury to the periodontal ligament when using heated guttapercha techniques such as "System B." An in vitro model was developed, consisting of an extracted human tooth rooted in an artificial periodontal ligament (PDL) and alveolar socket, which allowed us to measure the temperature transferred to the root surface. The teeth were instrumented and subsequently embedded in alginate to simulate the PDL. Medium gutta-percha points were fit, sealer was applied, and a fine Buchanan plugger was used for condensation. Temperature measurements were taken simultaneously at the apex and 5 mm from the apex during obturation with two fine gauge thermocouples connected to a digital thermometer. The average temperature increase was approximately 1 degree C at the apex and approximately 2 degrees C at the 5 mm mark. The resulting temperature increases appear to be lower than previously reported by other investigators (Hardie, 1986, 1987; Barkhordar et al., 1990; Weller et al., 1991; Lee et al., 1998), who did not allow for the heat disseminating effect of the PDL.

In vitro evaluation of apical leakage of root canal fillings after in situ obturation with thermoplasticized and laterally condensed gutta percha

The purpose of this investigation was to compare in vitro the sealing ability of root canal treatments performed in situ with injected thermoplasticized gutta-percha compared with the lateral condensation technique. Thirty single-rooted teeth with straight canals, due for extraction for orthodontic or periodontal reasons were prepared using a step-back technique. Teeth were then divided randomly into groups A and B and obturated, respectively, with the sectional injection thermoplasticized gutta-percha and the lateral condensation techniques. Teeth were extracted after 15 days, immersed in India ink for 3 days and the leakage was determined using area-metric analysis. The roots were ground transversally and the root portion was incrementaly removed with successive steps of 250 microns each, up to the coronal level of the dye penetration. Every section was photographed with a stereoscopic microscope under the same magnification (x20); 310 photographs were taken. Measurements of the area covered by ink as well as the whole cross-sectional area of the canal were made from each photograph with the aid of a digitizing computer. The measurements were subjected to non-parametric statistical analysis. No significant difference was found (P > 0.05). The technique of lateral condensation proved to be better in the first five sections (1.2 mm from the foramen) while thermoplasticized gutta-percha technique was superior in the rest of the root canal.

Sealing ability of sectional injection thermoplasticized gutta-percha technique with varying distance between needle tip and apical foramen

The purpose of this investigation was to evaluate the influence of the distance of the needle tip from the apical foramen on the apical seal and the length control of the root filling material when thermoplasticized gutta-percha is injected using a sectional injection technique. Ninety-nine human single-rooted mandibular incisors and permanent premolars with straight canals were divided into three equal Groups A, B and C. In Group A the teeth had relatively the wider root canal, in Group C the narrowest, while in Group B root canal size was intermediate. The root canals of all teeth were prepared with a step-back technique. Roots of Group A were instrumented to a Size 70 4 mm short of the working length, while roots of Groups B and C to a Size 70 6 mm and 8 mm short of the working length, respectively. The teeth of all groups were covered with aluminium foil and embedded in acrylic blocks. After the placement of sealer (Roth 811) the root canals of all teeth were obturated with injection-molded thermoplasticized gutta-percha using a three-stage sectional technique. The roots remained in India ink for three days and then cleared by successive immersion in nitric acid, ascending grades of alcohol and finally in xylene. The linear dye penetration and the linear apical underextentionion of the root canal filling were measured by two independent examiners under a stereo microscope. There was no significant difference in the linear dye leakage between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical experience in root canal obturation by an injection thermoplasticized gutta-percha technique

Forty-one human teeth with a total of 71 root canals were obturated with the high-temperature injected thermoplasticized technique (Obtura). Patients were recalled 6 to 36 months postoperatively. Cases were evaluated on the basis of clinical and X-ray findings. The success rate was 93.1%.

Apical placement of needle tip with an injection-thermoplasticized gutta-percha technique for root canal obturation

It is recommended that when injection-thermoplasticized gutta-percha is used as the obturation technique, the root canal space should be prepared in such a way that the 23-gauge injection needle tip can be placed at a distance 3 to 5 mm short of the working length. In this study the apical seal and extent of gutta-percha were evaluated when the 23-gauge tip was placed at a distance 4 mm, 6 mm, and 8 mm short of the working length. Ninety-nine human single-rooted mandibular incisors and premolars divided into 3 equal groups were used. Their crowns were separated at the cementoenamel junction and their roots were stored in sodium hypochlorite for 1 week. The roots were then instrumented from size 20 at the working length to size 70:4 mm short of the working length in group A, 6 mm in group B, and 8 mm in group C. Following instrumentation, 3 randomly selected roots of each group were used as control. The remaining 30 roots of each group were covered with aluminium foil and embedded in acrylic blocks. The root canals were then dried, coated with sealer (Roth 811) and obturated by injection of thermoplasticized gutta-percha using the single-phase technique. Vertical condensation followed. The roots were immersed in dye for 3 days and then demineralized, dehydrated and cleared in xylene. Measurements of linear dye penetration for the apical seal and for underextension were done by 2 independent examiners under a stereomicroscope. The results of this study showed no statistically significant difference in leakage between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Sealing ability of thermoplasticized gutta-percha in root canal obturation using a sectional vs. a single-phase technique

Properly prepared straight root canals of freshly extracted maxillary canines and central incisors were used to evaluate the sealing ability of the sectional thermoplasticized gutta-percha obturation technique, with or without sealer and the single-phase thermoplasticized gutta-percha filling technique. The teeth were divided into 3 groups (A, B, C) of 20 teeth and were obturated using the 3 thermoplasticized gutta-percha techniques. Group A: single phase with sealer; group B: sectional technique without sealer; and group C: sectional technique with sealer. The obturated teeth were immersed in India ink for 3 days followed by clearing procedures. The teeth were then examined under a stereo microscope and the linear leakage was recorded. Statistical unpaired Student's t-tests showed significantly less dye penetration in teeth obturated using the sectional technique with sealer (group C) than in teeth obturated with the single-phase technique with sealer (group A) or the sectional technique without sealer (group B).