|Year : 2019 | Volume
| Issue : 7 | Page : 926-931
Comparison of warm vertical compaction and cold lateral condensation of α, β gutta-percha and resilon on apically extruded debris during retreatment
BC Canakci, R Sungur, O Er
Department of Endodontics, Faculty of Dentistry, Trakya University, Edirne, Turkey
|Date of Acceptance||08-Mar-2019|
|Date of Web Publication||11-Jul-2019|
Dr. B C Canakci
Trakya University, Faculty of Dentistry, Department of Endodontics, Edirne
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: This study was performed to evaluate the amount of apically extruded debris removed from a root canal filled with cold lateral condensation (CLC), and warm vertical compaction (WVC) techniques, using b or a phase gutta-percha with AH-Plus (Dentsply DeTrey, Konstanz, Germany) or Resilon (Resilon Research LLC, Madison, WI) with RealSeal SE (SybronEndo, Amersfoort, The Netherlands). Materials and Methods: About 100 human incisor teeth were prepared with a #25.06 NiTi rotary system and divided into five groups according to the filling material used: Group 1: CLC (gutta-percha, AH-Plus); Group 2: WVC (b phase gutta-percha, AH-Plus); Group 3: WVC (a phase gutta-percha, AH-Plus); Group 4: CLC (Resilon, RealSeal SE); and Group 5: WVC (Resilon, RealSeal SE). Extruded debris during the retreatment procedure was collected in preweighed Eppendorf tubes. The times required for retreatment were recorded. Results: The amount of debris extrusion was significantly greater with WVC than CLC in the gutta-percha and Resilon groups (P < 0.001). Using a phase gutta-percha resulted in significantly more debris extrusion than b phase gutta-percha (P < 0.001). In the WVC groups, Resilon caused significantly more debris extrusion than gutta-percha (P < 0.05). Retreatment was faster for CLC than WVC (P < 0.05). Conclusions: In the retreatment procedure, the amount of apically extruded debris and retreatment duration were dependent on the type of obturation material and technique used.
Keywords: Apical extrusion, warm vertical compaction, a phase gutta-percha, b phase gutta-percha, Resilon
|How to cite this article:|
Canakci B C, Sungur R, Er O. Comparison of warm vertical compaction and cold lateral condensation of α, β gutta-percha and resilon on apically extruded debris during retreatment. Niger J Clin Pract 2019;22:926-31
|How to cite this URL:|
Canakci B C, Sungur R, Er O. Comparison of warm vertical compaction and cold lateral condensation of α, β gutta-percha and resilon on apically extruded debris during retreatment. Niger J Clin Pract [serial online] 2019 [cited 2019 Jul 22];22:926-31. Available from: http://www.njcponline.com/text.asp?2019/22/7/926/262536
| Introduction|| |
The debris containing root canal filling materials, dentin, microorganisms, and irrigants may be extruded from the apical foramen during retreatment procedures, regardless of the technique, instrument, or material used. This can cause periapical inflammation, flare-up, and disruption of the healing process, which may be more likely with increasing amount of extruded debris.
The different materials and methods—generally a solid core material with an endodontic sealer—are used for root canal system obturation. Gutta-percha is the most commonly used material for this purpose due to its stability and ability to be plasticized by heating. The gutta-percha polymer, trans-polyisoprene, can exist in two crystalline and/or stereochemical forms as a (alpha) and b (beta). Naturally occurring gutta-percha exists in the a-crystalline phase, and if a gutta-percha is cooled at a rate greater than 0.5°C per hour it can be transformed into the b phase. Most dental gutta-percha exists in the b semi-crystalline state, although some manufacturers produce an a phase gutta-percha. Providing an adequate seal with gutta-percha is difficult due to the absence of bonding to root canal dentine and endodontic sealer.
As an alternative, a synthetic polymer-based material, Resilon (Resilon Research LLC, Madison, WI), which shows thermoplastic ability similar to gutta-percha, has been introduced  for use with methacrylate-based sealer to enable monoblock according to their compositions and adhesive properties, and to improve the bond to the root canal dentine. RealSeal SE (SybronEndo, Orange, CA) is a fourth-generation self-adhesive methacrylate resin-based sealer recommended for use with Resilon, as the core material, in cold lateral condensation (CLC) or warm vertical compaction (WVC) techniques.
CLC is the most commonly used root canal obturation technique. However, its ability to adjust to the root canal system is questionable, as a number of problems, including the occurrence of voids, spreader tracts, incomplete cone fusion, and canal wall adaptation, have been reported. Several obturation techniques have been recommended to overcome these disadvantages. The WVC techniques, and a number of variations therein, were introduced for optimal three-dimensional filling with the flow of thermoplasticized gutta-percha. Generally the devices designed for the down-packing, and back-filling for WVC function by heating the obturation material with special tips up to 150–200°C. The rise of the temperature may result in heat dissipation to the root canal surface and periapical tissues.
The previous studies generally compared the effects of various retreatment systems and materials on the amount of extruded debris during retreatment. To our knowledge, there have been no studies comparing the removal of root canal fillings performed with b and a phase gutta-percha versus Resilon with different obturation techniques. The present in vitro study was performed to evaluate the amounts of apically extruded debris removed from root canals filled with CLC and WVC, using b/a phase gutta-percha with AH-Plus (Dentsply DeTrey, Konstanz, Germany), or Resilon with Real Seal SE. The null hypothesis was that the amount of apically extruded debris would be unaffected by the filling technique or materials used.
| Materials and Methods|| |
This study was approved by the Ethics Committee of Trakya University, Medical Scientific Research Committee, Edirne, Turkey (TUTF-BAEK, 2016/48). In total, 100 freshly extracted human mandibular central teeth with a single root canal, mature apex, and root canal curvature of <10° were used. The radiographs were taken to ensure that there was no internal resorption or root canal calcification. Soft tissue remnants and calculi on the external root surface were removed by hand, and using ultrasonic devices.
All teeth were shortened to 20 mm by flattening the incisal edge and a coronal access cavity was opened using a diamond bur (Diatech; Coltene Whaledent, Altststten, Switzerland), and a high-speed handpiece under water cooling. The working length (WL) was determined as 1 mm short of the length of a size 10-K file (Dentsply Maillefer, Ballaigues, Switzerland), so that the tip of the file was visible at the major apical foramen under an operating microscope (Opmi Pico; Carl Zeiss, Oberkochen, Germany).
All teeth were prepared with a RevoS SC2 (#25.04) (Micro-Mega SA, Besançon, France) and RevoS SU (#25.06) instruments to the WL, according to the manufacturer's recommendations. Apical canal patency was controlled with a size 10-K file.
During the instrumentation procedure, the canals were irrigated with 2-mL 5% sodium hypochlorite (NaOCl) (Cerkamed Company, Stalowa Wola, Poland) between each file using a syringe and a 29-G double-side port NaviTip irrigation needle (Ultradent, South Jordan, UT). After completion of the preparation, 5 mL of 17% EDTA (Cerkamed Company), 5-mL of 5% NaOCl, and 10 mL of distilled water (Can Medikal, Edirne, Turkey) were used. The root canals were then dried with paper points (VDW GmbH, Munich, Germany) and divided randomly into five experimental groups (n = 20).
Group 1: CLC, Gutta-percha/AH-Plus
A #25.06 standardized master gutta-percha cone (VDW) was fitted to the WL to check tug-back. An AH-Plus sealer was used. The sealer was introduced into the root canal using a Lentulo spiral filler (Dentsply Maillefer). Master gutta-percha cone was coated with a sealer and placed into the root canal. The accessory cones (VDW) were laterally compacted until the size 20 finger spreader could no longer penetrate into the coronal one third of the root canal. On average, four accessory cones were used per tooth.
Group 2: WVC, β phase gutta-percha/AH-Plus
A #25.06 b phase gutta-percha (VDW) was fitted to the WL to check tug-back. An AH-Plus sealer was introduced into the root canal using a Lentulo spiral filler. The 0.5-mm tip of the gutta-percha was trimmed, coated with a sealer and placed into the root canal, 0.5 mm short of the WL. A BeeFill™ (VDW) down-pack device was used for obturation of the apical part. This device was preset to 180°C during apical compaction of the gutta-percha. Hot plugger (Dentsply Maillefer) was applied, searing the points off approximately 3 to 4 mm from the apex. BeeFill™ (VDW) backfill device was used for the remainder of the root canal system, as recommended by the manufacturer. Vertical condensation was then performed using pluggers (Dentsply Maillefer).
Group 3: WVC, α phase gutta-percha/AH-Plus
The same procedure was used as in Group 2, but an a phase gutta-percha cone (VDW) was used as the master cone.
Group 4: CLC, Resilon/RealSeal SE
A #25.06 standardized Resilon cone was fitted to the WL to check tug-back. A RealSeal SE sealer was used. The RealSeal primer was applied on the root canal walls with the help of a microbrush and excess primer was removed by using paper points. The sealer was introduced into the root canal using a Lentulo spiral filler. Master cone was coated with a sealer and placed into the root canal. The accessory Resilon cones were laterally compacted until the size 20 finger spreader could no longer penetrate into the coronal one third of the root canal. The root canal filling was cured with a Bluephase LED light (Ivoclar Vivadent, Schaan, Liechtenstein; 1200 mW/cm 2) for 40 seconds. On average, four accessory cones were used per tooth.
Group 5: WVC, Resilon/RealSeal SE
A #25.06 Resilon was fitted to the WL to check tug-back. The 0.5-mm tip of the cone was trimmed and placed into the root canal 0.5 mm short of the WL. The RealSeal primer and RealSeal SE was used as the sealer. System B (Analytic Endodontics, Orange, CA) down-pack device was used for obturation of the apical part. Hot plugger was applied, searing the points off approximately 3 to 4 mm from the apex. An Obtura II gun (Obtura Spartan, Fenton, MO) was used for backfill, in accordance with the manufacturers' instructions. Vertical condensation was then performed using pluggers. Temperature in System B and Obtura III was set to 150°C. The root canal filling was cured with a Bluephase LED light (1200 mW/cm 2) for 40 seconds.
The root canal fillings were removed coronally with a heated instrument and limited to 16 mm from the apex. The access cavities were filled with a temporary filling material (Cavit; 3M ESPE, Seefeld, Germany). The quality of the root fillings was confirmed by radiography. The teeth were stored in an incubator at 37°C and 100% humidity for 8 weeks.
Next, all teeth were placed in a vial system, which had been pre-weighed three times using an analytical balance (AUW-220D; Shimadzu, Tokyo, Japan) with an accuracy of 10-5 g. Holes were made in the rubber stoppers of vials with a hot instrument. The tooth was inserted under pressure through the rubber stopper, which was fixed to the cementoenamel junction using cyanoacrylate. The rubber stopper with the tooth was then fitted into the mouth of the vial. The apical part of the root was suspended within the vial, which acted as a collecting container for apical material evaluated through the foramen of the root. A 25-gauge needle was placed through the rubber stopper to equalize the air pressure inside and outside the vial.
ProTaper Universal retreatment files (Dentsply Maillefer) D1 (#30.09), D2 (#25.08), and D3 (#20.07) were used according to the manufacturer's instructions to the WL for gutta-percha removal. For the final preparation, RevoS AS40 (#40.06) NiTi files were used to the WL. For each specimen, in total 20 mL of distilled water was used for irrigation. Each instrument was used for only one preparation.
Retreatment was deemed complete when no gutta-percha or sealer was visible on the instrument surface and the canal walls were smooth using a dental operating microscope. All procedures were performed by a single operator.
When the retreatment procedures were finished, the apical part of the tooth was washed with 1 mL of distilled water to collect the apically extruded debris that had adhered to the root apex in the vial. The rubber stoppers were removed from the glass vials, which were stored in an incubator at 68°C for 5 days to evaporate any moisture before weighing the dry debris. Glass vials that included dry extruded debris were weighed in the same manner as during the initial measurement. The weight of the extruded debris was determined by subtracting the weight of the preweighed empty glass vials from the weight of the tubes containing dried debris.
The times required for retreatment procedures were also recorded.
Data were subjected to one-way analysis of variance (ANOVA) and Tukey's test using SPSS software (ver. 22.0; SPSS Inc., Chicago, IL). In all analyses, P < 0.05 was taken to indicate statistical significance.
| Results|| |
The median weights of the extruded debris are presented in [Table 1], and the median retreatment durations are shown in [Table 2].
All groups using WVC showed significantly greater amounts of extruded debris than the CLC groups: Group 5 (WVC, Resilon) > Group 3 (WVC, a) > Group 2 (WVC, b) > Group 1 (CLC, gutta-percha) and Group 4 (CLC, Resilon). Using WVC, significantly more extrusion was observed with a phase gutta-percha (Group 3) than with b phase gutta-percha (Group 2).
The time of retreatment procedure was greater in all groups using WVC than in the CLC groups: Group 2 (WVC, b), Group 3 (WVC, a) and Group 5 (WVC, Resilon) > Group 1 (CLC, gutta-percha) and Group 4 (CLC, Resilon).
| Discussion|| |
During retreatment procedures, apical extrusion of debris may cause postoperative failure, depending on the amount of extruded debris. Only the two previous studies evaluated apically extruded debris during retreatment procedures from root canals obturated with different techniques and materials; one compared CLC, single-cone technique, and WVC using two different sealers with gutta-percha, while the other compared gutta-percha with CLC and single-cone with the use of solvents. In the present study, we evaluated the amounts of apically extruded debris from root canals filled with CLC and WVC using b/a phase gutta-percha and Resilon/RealSeal SE.
The results of this study indicated that with gutta-percha/AH-Plus as obturation materials, the WVC technique resulted in significantly greater amounts of extruded debris than CLC, similar to the results of Topçuoǧlu et al. There may be several reason for this difference between the two techniques. First, with the flow of plasticized gutta-percha in WVC, irregularities, fins, recesses, and accessory and lateral canals can be filled, thus providing better adaptation to the dentinal walls  and better sealing ability  than CLC. In addition, WVC provides more homogenous dense root canal filling  with a lower percentage of voids  and greater mass of gutta-percha  than CLC. Finally, the presence of spreader tracts and the greater amount of seal in CLC may reduce the adaptation of gutta-percha and the homogenous obturation material mass. Therefore, superior obturation quality may result in more difficult removal of root canal filling and a greater amount of apically extruded debris.
In this study, when WVC was used with gutta-percha/AH-Plus, the use of a phase gutta-percha as the master cone caused a significantly greater amount of apically extruded debris than seen with use of b phase. When heated, the components of gutta-percha, such as polyisoprene, can be degraded, resulting in loss of stability of the material; molar mass reduction may also occur. This can negatively affect the sealing ability of root filling at different heat levels with different types and brands of gutta-percha. In addition, the thermoplasticity of different types of gutta-percha is affected by their chemical compositions, with a phase gutta-percha showing better fluidity and ability to adapt to dentin walls than b phase gutta-percha., In addition, a phase gutta-percha has superior properties with regard to shrinkage, stiffness elongation and tension.,
With Resilon/Real Seal SE, use of the WVC technique resulted in significantly greater amounts of apically extruded debris than were seen with CLC. Although there have been reports of similar sealing ability of cold and heated obturation with Resilon,, with similar thermal behavior to gutta-percha, the material has the ability to flow into root canal irregularities, which may result in more adaptance to dentin walls and irregularities, more penetration to lateral canals and resistance to removal procedures.
We found that with CLC, using Resilon/RealSeal SE or gutta-percha/AH-Plus caused no significant differences in the amount of apically extruded debris. Considering the sealing ability, strength of bonding to dentin, and leakage, although some studies reported the superiority of Resilon  or gutta-percha, these materials have generally similar properties. Obturation with Resilon exhibited more voids, but RealSeal SE  showed deeper penetration into dentinal tubules than AH-Plus.
The results of this study indicated that with the WVC technique, use of Resilon/RealSeal SE caused significantly more debris extrusion than gutta-percha/AH-Plus. This may have been because of the higher thermoplasticity of Resilon than conventional and thermoplastic gutta-percha, resulting in a greater ability to fill irregularities and lateral canals. Conversely, some authors reported no differences between Resilon and gutta-percha in terms of flowability into grooves and depressions. In addition, these observations may be related to the bonding effect of the material  and higher tubular penetration of sealer.
Root canals filled with WVC required a significantly longer time for the retreatment procedure, similar to the results reported previously., There were no significant differences between gutta-percha and Resilon groups, similarly to some previous reports, although other reports indicated shorter times for Resilon  or gutta-percha.
| Conclusion|| |
Within the limitations of this study, in the retreatment procedure, the amount of apically extruded debris and the time required for retreatment procedure were dependent on the type of obturation material (a - b phase gutta-percha, Resilon) and technique (CLC, WVC) used.
Financial support and sponsorship
Supported by Trakya University Scientific Research Projects Unit with TDK (project number 2017/101).
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]