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

doi:10.1016/j.joen.2005.10.047

Journal of Endodontics

Volume 32, Issue 5, May 2006, Pages 438-441

https://doi.org/10.1016/j.joen.2005.10.047 Get rights and content

Abstract

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°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°C to fill the maxillary central incisors and mandibular central incisors resulted in the rises of the root surface temperature by 8.5°C and 22.1°C, respectively. In conclusion, the injection of the gutta-percha heated to 160°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°C.

Section snippets

Materials and Methods

Thirty extracted human teeth with a single canal (15 maxillary central incisors and 15 mandibular central incisors) were used in this study. Teeth were divided into two groups of 15 teeth each. Group 1 consisted of maxillary central incisors and group 2 of mandibular central incisors. All specimens were microscopically inspected to disclose any defects or root fractures and to confirm complete formation of apices.

An access cavity to the pulp chamber was prepared and the contents of the pulp

Results

The mean temperature rise recorded on the outer root surfaces of the maxillary central incisors was 8.5 ± 2.4°C (4.9-13.6), while the rise in the mandibular central incisors was 22.1 ± 7.3°C (14.9-37.2). The difference was highly significant (p = 0.000003).

Figure 1 shows the graphic representation of mean temperature changes. In both maxillary and mandibular incisors, the injection of heated gutta-percha into the root canal produced a two peak temperature elevations. The first showed a lower

Discussion

This in vitro study investigated the outer root surface temperature increases during root canal obturation with high-temperature thermoplasticized injectable gutta-percha. The temperatures were measured using a thermal imaging infrared camera on the outer root surface of teeth with different root dentin wall thickness. It showed temperature rises of less than 10°C on the outer root surface of the maxillary central incisors and, therefore, should not have an adverse effect on the attachment

Acknowledgment

This research was supported by State Committee for Scientific Research; Komitet Badań Naukowych (Grant No. 4 P0 5E 13119).

References (30)

D.B. Kirkham
The location and incidence of accessory canals in periodontal pockets
J Am Dent Assoc
(1975)
Q.D. DeDeus et al.
Frequency, location and direction of the lateral, secondary, and accessory canals
J Endod
(1975)
C.S. Lea et al.
Comparison of the obturation density of cold lateral compaction versus warm vertical compaction using the continuous wave of condensation technique
J Endod
(2005)
M. Venturi et al.
Evaluation of apical filling after warm vertical gutta-percha compaction using different procedures
J Endod
(2004)
J.G. Cailleteau et al.
Prevalence of teaching apical patency and various instrumentation and obturation techniques in United States dental schools
J Endod
(1997)
F. Meister et al.
Diagnosis and possible causes of vertical root fractures
Oral Surg Oral Med Oral Pathol
(1980)
S.M. Brayton et al.
Gutta-percha root canal fillings
Oral Surg Oral Med Oral Pathol
(1973)
M. Wong et al.
Comparison of gutta-percha filling techniques, compaction (mechanical), vertical (warm) and lateral condensation techniques. Part I
J Endod
(1981)
B.G. Soyenkoff et al.
Thermal conductivity measurements of dental tissues with the aid of thermistor
J Am Dent Assoc
(1958)
Fl Lee et al.
A comparison of root surface temperatures using different obturation heat sources
J Endod
(1998)

M. Lipski

Root surface temperature rises in vitro during root canal obturation with thermoplasticized gutta-percha on a carrier or by injection

J Endod

(2004)

M. Lipski

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

Oral Surg Oral Med Oral Pathol Oral Radiol & Endod

(2005)

M. Lipski

Root surface temperature rises in vitro during root canal obturation using hybrid and Microseal techniques

J Endod

(2005)

A.R. Eriksson et al.

Temperature threshold levels for heat-induced bone tissue injurya vital-microscopic study in the rabbit

J Prost Dent

(1983)

J.L. Gutmann et al.

Evaluation of heat transfer during root canal obturation with thermoplasticized gutta-percha. Part II. In vivo response to heat levels generated

J Endod

(1987)

Cited by (32)

Real-time Intracanal Temperature Measurement During Different Obturation Techniques
2018, Journal of Endodontics
The purpose of this study was to assess temperature development in endodontic sealers during different obturation techniques in a closed system simulating the surrounding biological structures at body temperature.
The root canals of 48 human single-rooted maxillary canines were instrumented with ProTaper Gold (Dentsply Sirona, York, PA) to size F3. On the buccal aspect of each root, artificial side canals with a diameter of 0.5 mm were drilled at a distance of 3, 6, and 9 mm from the apical foramen, and type K thermocouples were inserted via plastic pipes. The roots were positioned in plastic vials filled with alginate. The root canals were obturated by the continuous wave and warm backfill technique, Thermafil obturators (Dentsply Sirona), or single-cone obturation (n = 12) at body temperature using AH Plus sealer (Dentsply Sirona). Temperature measurement during the obturation procedure was assessed by thermocouples. Statistical analysis of the maximum temperature change was performed using the Kruskal-Wallis test (P = .05).
The continuous wave and warm backfill technique caused significantly higher temperatures than Thermafil and single-cone obturation (P < .05). The continuous wave technique revealed significantly higher temperatures than the warm backfill technique at 3 mm and 6 mm from the apex (P < .05).
In a closed system with simulated surrounding tissues at 37°C, the continuous wave technique produced higher increases in temperature than the warm backfill technique with a maximum of 19.1°C. The temperature increase during Thermafil obturation was negligible. The temperature increase in the endodontic sealer was markedly lower than expected from root surface temperature measurement studies.
Periodontal Blood Flow Protects the Alveolar Bone from Thermal Injury during Thermoplasticized Obturation: A Finite Element Analysis Study
2018, Journal of Endodontics
The purpose of this study was to investigate the heat transfer during thermoplastic obturation and the cooling capacity of blood flow in the periodontal ligament (PDL) using finite element analysis (FEA).
A 3-dimensional digital tooth model was constructed based on micro–computed tomographic scanning of a mandibular first molar after chemomechanical preparation in vitro. A layer of PDL with or without simulated blood flow was built on the root portion of the tooth in software. Two heat-assisted obturation techniques (ie, the single-wave condensation technique and the warm vertical compaction technique followed by backfilling with injectable gutta-percha) were examined using an FEA package.
In the model without blood flow, the highest temperature at the alveolar bony aspect of the PDL was 50.0°C along the distal canal and 52.5°C for the mesiolingual canal when the single-wave technique was used. With the warm vertical compaction technique, the highest temperature was 47.3°C for the distal canal and 47.8°C for the mesiolingual canal. In the model with simulated periodontal blood flow, a notable drop in the peak temperatures at the root surface and at the adjoining alveolar bone was observed for both the distal and mesiolingual canals; all peak temperatures at the PDL fell below 47°C regardless of the obturation techniques used. The greatest rise in temperature was situated at the furcation aspect of the middle third of both roots.
The cooling capacity of blood flow in the PDL is a factor that must be considered in the investigation of heat transfer during thermoplastic obturation.
Temperature changes on external root surfaces with the use of several thermoplastic filling techniques
2016, Journal of Endodontics
Citation Excerpt :
However, facing the surveyed methodologies, the thermocouples seem to be the most appropriate resource for this kind of experiment. Infrared cameras are also used to measure the temperature changes on the external root surface (22–24). However, the camera calibration for emissivity of the root tissue, distance from the root to the camera, and ambient temperature are difficult variables to control (25).
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.
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.
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).
There was a rise of temperature on the external root surface for all of the techniques evaluated. TC showed the lowest temperature rise.
In Vivo Intracanal Temperature Evolution during Endodontic Treatment after the Injection of Room Temperature or Preheated Sodium Hypochlorite
2015, Journal of Endodontics
Citation Excerpt :
Different methods have been used to measure temperature changes of and in teeth. The use of infrared thermography (23, 24) and thermocouples (25) in in vitro studies has been described. These studies investigated temperature changes in extracted teeth (26), root canal models (27), or an experimental design that simulated the heat-dissipating role of the radicular supporting tissues (17, 28).
Heating a sodium hypochlorite solution improves its effectiveness. The aim of this study was to measure the in vivo temperature changes of sodium hypochlorite solutions that were initially preheated to 66°C or at room temperature inside root canals during routine irrigation.
Thirty-five root canals were prepared to ISO size 40 with 4% taper. A type K (nickel-chromium-nickel) thermocouple microprobe (Testo NV, Ternat, Belgium) was positioned within 3 mm of the working length to measure the temperature at 1-second intervals. In each canal, 2 test protocols were evaluated in a randomized order with 3% sodium hypochlorite solutions: (1) preheated to 66°C and (2) at room temperature. The temperature measurements began 5 seconds before the 25 seconds of irrigant injections and continued for 240 seconds. This resulted in 270 data points for each protocol.
The temperature of the irrigant at room temperature increased from the initial intracanal temperature after injection of 20.7°C (±1.2°C) to 30.9°C (±1.3°C) in 10 seconds and to 35°C (±0.9°C) after 240 seconds. The temperature of the preheated to 66°C solution decreased from 56.4°C (±2.7°C) to 45.4°C (±3.0°C) after 5 seconds, reached 37°C (±0.9°C) after 60 seconds, and reached 35.7°C (±0.8°C) after 240 seconds.
The original temperatures of the sodium hypochlorite solutions were buffered inside the root canal and tended to rapidly evolve to equilibrium. The findings of this study contribute to an improved understanding of the thermodynamic behaviors of irrigant solutions inside root canals in vivo.
Thermoplastic properties of endodontic gutta-percha: A thermographic in vitro study
2015, Journal of Endodontics
Citation Excerpt :
Infrared thermal imaging proved to be an accurate and descriptive research method. It has been used previously to investigate the temperature achieved during thermoplastic root canal filling (12–15); yet, to the best of our knowledge, it has never been used to measure the temperature behavior of heat carriers and/or root canal filling materials. Infrared thermography is able to produce precise images, thus allowing fine-resolution measurements when reflections are avoided and the room temperature is maintained constant.
Endodontic gutta-percha undergoes deformation at temperatures above 65°C. The temperature influence of heat carriers on gutta-percha cones was investigated in vitro.
Six single-rooted extracted teeth were embedded in resin and fixed. The root canals were prepared (ProFile; Dentsply Maillefer, Ballaiques, Switzerland) to different tapers and bisected. Thermographic images when heating the gutta-percha cones (Roeko, Langenau, Germany) with a heat carrier (ML .12; SybronEndo, Orange, CA) at 1 and 5 mm from the working length were made with an infrared thermal imaging camera (ThermaCam P640; Flir Systems, Täby, Sweden). The device temperature was preset at 200°C. The pixel temperature registered at the contact lines between the heat carriers and gutta-percha cones in the thermographic images was recorded and statistically described.
A mean temperature (°C) instability in the heat carrier (324.96 ± 46.10, minimum = 147.35, maximum = 474.13), a temperature drop of the gutta-percha cones (159.52, ±37.57, min 67.64, max 259.04) at the measuring level, and a mean temperature penetration depth (mm) equal or to higher than 65°C (1.05 ± 0.28, minimum = 0.20, maximum = 1.30) were recorded. No correlation between the penetration depth into the gutta-percha cones and applied temperatures, regardless of the size and/or taper, could be established.
Temperature discrepancies between the device preset and achieved ones of the heat carriers was observed. Gutta-percha is a poor thermal conductor, transports heat irregularly, and should be heated 1–2 mm from the target area.
Heat transfers to periodontal tissues and gutta-percha during thermoplasticized root canal obturation in a finite element analysis model
2010, Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology
The aim of this study was to measure the temperature distributions on the periodontal ligament and apical gutta-percha during thermal obturation with different plugger activation time.
The multirooted model of mandibular first molar development and root canal treatment were performed by finite element analysis. The apical thirds of canals were obturated by continuous-wave condensation technique, with 3 seconds and 4 seconds of activation time. The remainder was backfilled with injected gutta-percha in 2 segments (Obtura II).
The highest temperatures on the periodontal ligament reached 46.914°C and 48.887°C, in the “dangerous zone” between the root canals, when activation times were 3 seconds and 4 seconds, respectively. The greatest temperature rise within the apical gutta-percha was only 0.859°C.
With 3 seconds of activation, the temperature elevation reached almost 47°C, so one should be careful not to extend the activation time beyond 3 seconds, which is clinically difficult to control. The apical gutta-percha temperature was always below the desired level to achieve proper thermoplasticity.

View all citing articles on Scopus

View full text

Basic research—technologyIn Vitro Infrared Thermographic Assessment of Root Surface Temperatures Generated by High-Temperature Thermoplasticized Injectable Gutta-Percha Obturation Technique

Abstract

Section snippets

Materials and Methods

Results

Discussion

Acknowledgment

J Am Dent Assoc

J Endod

J Endod

J Endod

J Endod

Oral Surg Oral Med Oral Pathol

Oral Surg Oral Med Oral Pathol

J Endod

J Am Dent Assoc

J Endod

J Endod

Oral Surg Oral Med Oral Pathol Oral Radiol & Endod

J Endod

J Prost Dent

J Endod

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