Intracanal temperature rise evaluation during the usage of the System B: replication of intracanal anatomy

Plugger temperature of cordless heat carriers according to the time elapsed

Objective

The purpose of this study was to measure the temperature of the plugger tip of 3 cordless heat carriers set at 200°C.

Materials and Methods

Pluggers of the same taper (0.06, 0.08, 0.10) and similar tip sizes (sizes of 50 and 55) from 3 cordless heat carriers, namely SuperEndo-α² (B & L Biotech), Friendo (DXM), and Dia-Pen (Diadent), were used and an electric heat carrier, System B (SybronEndo), was used as the control. The plugger tips were covered with customized copper sleeves, heated for 10 seconds, and the temperature was recorded with a computerized measurement system attached to a K-type thermometer at room temperature (n = 10). The data were analyzed with 2-way analysis of variance at a 5% level of significance.

Results

The peak temperature of the plugger tips was significantly affected by the plugger taper and by the heat carrier brand (p < 0.05). The peak temperature of the plugger tips was between 177°C and 325°C. The temperature peaked at 207°C-231°C for the 0.06 taper pluggers, 195°C-313°C for the 0.08 taper pluggers, and 177°C-325°C for the 0.10 taper pluggers. Only 5 of the 12 plugger tips showed a temperature of 200°C ± 10°C. The time required to reach the highest temperature or 200°C ± 10°C was at least 4 seconds.

Conclusion

When using cordless heat carriers, clinicians should pay attention to the temperature setting and to the activation time needed to reach the intended temperature of the pluggers.

Thermal analysis and stability of commercially available endodontic obturation materials

OBJECTIVES

The purpose of this study was to evaluate the thermal stability of 23 commercially-available endodontic obturation materials.

MATERIALS AND METHODS

Specimens (n = 10) were sealed in aluminum differential scanning calorimetry (DSC) crucibles and subjected to thermal scan series consisting of a 25 to 70 °C at 5 °C/min followed by a rapid increase to 230 °C, followed by a second scan from 25 to 70 °C at 5 °C/min. The first scan evaluated the materials as-received followed by a worse-case-scenario thermal challenge simulating temperatures involved with warm vertical condensation obturation techniques. The second thermal scan observed any phase changes from the high temperature challenge. This two-scan process was repeated twice to observe changes encountered by repeat high heat exposure during obturation. Mean thermal enthalpies were analyzed with Kruskal-Wallis and Games-Howell post-hoc test. (p = 0.05).

RESULTS

Thermal behavior was material dependent. During the first thermal scan, materials typically demonstrated broad endothermic enthalpy curves suggesting either a gutta-percha phase mixture and/or an alpha crystalline phase. The first high-heat challenge produced definitive alpha/beta thermal phase signatures usually associated with gutta-percha. Changes in beta-phase enthalpies were noted with Therarmafil Plus and UltraFil Firmset while increase in alpha-phases was observed with GuttaCore, K3, Lexicon, and Schein Accessory Points.

CONCLUSIONS

Commercial endodontic gutta-percha obturation materials displayed thermal characteristics that were material dependent. However, all demonstrated stability at temperatures in excess to that experienced during warm vertical condensation techniques.

CLINICAL RELEVANCE

The gutta-percha obturation materials evaluated in this evaluation can be used successfully in warm vertical condensation techniques without fear of degradation.

System B, Endo-Twinn and E-Fill. True temperatures inside the canal

Background:

The aim of this study is to verify the variations of the temperature inside the root canal with three different gutta-percha heating systems.

Materials and Methods:

A split-tooth model was built with a lateral groove at 3.5-mm from working length (WL) in order to insert a Chromel-Alumel K-type thermocouple placed in contact with gutta-percha. The thermocouple was connected to a digital thermometer. Sixty obturations were made with medium gutta-percha points. For 20 specimens the System B was used with the Buchanan fine plugger and the temperature was set at 200°C; for other 20 specimens the Endo-Twinn with a fine plugger was used and for the last 20 specimens we used the E-Fill with a 40.04 plugger. All pluggers were pushed to 3.5 mm from WL so that the tips were in contact to the probe.

Results:

The analysis of 60 samples showed the highest temperature average using the System B after 10 seconds (86.85°C), after 15 seconds (94.9°C), after 20 seconds (100.4°C) and after 25 seconds (104.5°C). The Endo-Twinn average values are similar to System-B ones. The E-Fill average values are lower (69.9°C) than the other two systems evaluated only after 10 seconds due to limited working time. The temperatures average obtained using different systems of warm vertical compaction are lower than what was declared by the producing companies.

Conclusion:

Time is one the most important parameters to consider using these systems. Temperatures reached from the System B and Endo-Twinn after 25 seconds; however, seem to be sufficient to ensure an optimal adaptation of the gutta-percha in the anatomical complexity of root canals. The temperatures obtained from the E-Fill, only after 10 seconds, instead seems to be insufficient to assure the rheological characteristics of gutta-percha.

An ex vivo comparison of three different gutta-percha cones when compacted at different temperatures: rheological considerations in relation to the filling of lateral canals

AIM

To compare ex vivo the penetration of three brands of gutta-percha cones, compacted under a constant force and heated to different temperatures, into artificial lateral canals.

METHODOLOGY

Resin blocks with simulated main canals, each having two lateral canals (C at 6.5 and A at 13 mm from the surface of the resin block), were selected. A gutta-percha cone, either Mynol MF, Hygenic MF or GT Tulsa 0.04 was compacted into each main canal for 5 s using a wire rod with a diameter of 0.7 mm soldered to the bottom of a metal cylinder, with a force of 2.7 kg at controlled temperatures of 37, 42, 47, 52, 60 degrees C. The penetration of each brand of gutta-percha into 60 lateral canals (10 at each temperature) was measured using a stereomicroscope. Statistical analysis was performed using the ANOVA, the Scheffè test and the t-test.

RESULTS

None of the three brands of cones entered up to 0.1 mm within either lateral canal until a temperature of 47 degrees C was reached; at that temperature only Mynol cones (P < or = 0.05) penetrated in four of 10 A-level canals (mean 0.13 +/- 0.19 mm) and in all 10 C-level canals (mean 0.43 +/- 0.12 mm). The A-level lateral canals were penetrated at 52 degrees C by Mynol cones (mean 0.76 +/- 0.34 mm) to a significantly greater distance (P < or = 0.05) than Tulsa cones (mean 0.31 +/- 0.12 mm) and Hygenic cones (mean 0.11 +/- 0.08 mm). At 60 degrees C the Mynol cones (mean 1.93 +/- 0.34 mm) penetrated significantly more (P < or = 0.05) than the Tulsa cones (mean 0.86 +/- 0.22 mm) and Hygenic cones (mean 0.67 +/- 0.19 mm). The C-level lateral canals were penetrated at 52 degrees C by Mynol cones (mean 0.91 +/- 0.29 mm) to a significantly greater distance (P < or = 0.05) than Tulsa cones (mean 0.47 +/- 0.16 mm) and Hygenic cones (mean 0.46 +/- 0.15 mm), whilst no significant difference was found at 60 degrees C.

CONCLUSIONS

When heated and compacted, the three gutta-percha cones penetrated the lateral canals to different degrees. They penetrated more than 0.43 mm into the lateral canals only at temperatures higher than 47 degrees C.

Evaluation of canal filling after using two warm vertical gutta-percha compaction techniques in vivo: a preliminary study

AIM

To evaluate the quality of root canal filling when comparing two warm gutta-percha filling techniques in vivo.

METHODOLOGY

Human teeth were randomly divided into two equal groups, with 30 canals each. The root canals were shaped by hand and ProFile 0.04 rotary instruments to size 20-40 at the end-point and then filled with gutta-percha cones and AH-Plus. In group A, a traditional warm vertical compaction technique was performed using the Touch'n Heat, and back-filling with the Obtura II. In group B, a modified warm vertical compaction technique was used: small amounts of gutta-percha were removed, and the remaining most apical 3 mm were compacted with a 1 mm movement; then thermomechanical back-filling was performed. The teeth were extracted, stored in dye, cleared, and the distance between the apex and apical limit of the filling, linear dye penetration, and voids were measured from the buccal, lingual, mesial and distal perspective. The homogeneity of variance and means was verified using Levene's test and t-test. ANOVA and Dunnett post hoc test were used to establish the significance and to analyse the effects through multiple comparisons.

RESULTS

Compared with the specimens of group A, the specimens of group B exhibited less mean linear dye penetration (P < 0.05), smaller void length (P < or = 0.05) and maximal width (P < or = 0.05) when examined in all four views, and a more precise filling when viewed from the buccal aspect (P < 0.05).

CONCLUSIONS

The modified warm vertical compaction technique with apical back-filling produced a more effective and precise three-dimensional filling.