|Year : 2014 | Volume
| Issue : 1 | Page : 53-57
Gutta percha verses resilon: An in vitro comparison of fracture resistance in endodontically treated teeth
Jyothi Shashidhar1, C Shashidhar2
1 Department of Pedodontics and Preventive Dentistry, Modern Dental College and Research Center, Airport Road, Indore, Madhya Pradesh, India
2 Department of Conservative Dentistry and Endodontics, Modern Dental College and Research Center, Airport Road, Indore, Madhya Pradesh, India
|Date of Web Publication||15-Feb-2014|
1663/56, "Chandragiri," 10th Main,11th Cross, Siddaveerappa Extension, Shamanur Road, Davangere - 577 004, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective: The aim of this study was to evaluate and compare the fracture resistance of endodontically treated teeth filled with gutta percha and Resilon using lateral and vertical condensation methods. Materials and Methods: A total of 75 freshly extracted single-rooted teeth were selected. All samples were instrumented with profile 4% Ni-Ti rotary instruments. Samples were randomly divided into five groups of 15 samples each: Group 1 was obturated using lateral condensation with gutta percha and AH -26 sealer. Group 2 was obturated using vertical condensation with gutta-percha and AH-26. Group 3 was obturated with Resilon and epiphany using lateral condensation technique. Group 4 was obturated with Resilon and epiphany using vertical condensation method. Group 5 received no filling. Restored teeth were subjected to compressive loading in a universal testing machine. Results: One-way ANOVA test showed significant difference among the groups (P < 0.05). The mean and SD values for the groups are as follows: Group 1 - (773.3 ± 148.1), Group 2 - (769.9 ± 170.5), Group 3 - (928.1 ± 135.4), Group 4 - (902.6 ± 120.8), and Group 5 - (766.0 ± 152.0). It was seen that samples of Group 3 showed the highest fracture resistance followed by Group 4, Group 1, and Group 2. Group 5 showed the least fracture resistance. Conclusion: Resilon-epiphany obturated roots using lateral condensation method showed higher fracture resistance compared with gutta percha-AH 26 groups on vertical loading.
Keywords: AH-26, epiphany, gutta-percha, lateral condensation, Resilon, vertical condensation
|How to cite this article:|
Shashidhar J, Shashidhar C. Gutta percha verses resilon: An in vitro comparison of fracture resistance in endodontically treated teeth. J Indian Soc Pedod Prev Dent 2014;32:53-7
|How to cite this URL:|
Shashidhar J, Shashidhar C. Gutta percha verses resilon: An in vitro comparison of fracture resistance in endodontically treated teeth. J Indian Soc Pedod Prev Dent [serial online] 2014 [cited 2019 Sep 19];32:53-7. Available from: http://www.jisppd.com/text.asp?2014/32/1/53/127058
| Introduction|| |
The primary objective of root canal therapy is complete obturation of the root canal system. It is known that endodontic treatment results in reduction of fracture strength of teeth. , Biomechanical preparation and dehydration effects of the irrigant solutions are the causative factors that weaken the tooth structure. , Therefore, one of the aims of filling the root canals must be to reinforce the root canal dentin to increase the fracture resistance.
Obturation is one of the most critical steps in root canal therapy. Hence, it should be performed according to the highest clinical standards. Gutta percha used in conjunction with root canal sealers may have been the best combination available to date and is seen as the gold standard of root canal fillings. Despite its many advantages and having achieved the status of a time-honored material, gutta percha still has its limitations, like its inability to strengthen root as it does not bond to dentin. Although few materials have seriously challenged gutta percha in the majority of filling situations, research continues to find alternatives that may seal better and mechanically reinforce compromised roots. ,
In recent years, a new resin-based obturation material, Resilon (Resilon Research LLC, Madison, CT, USA; Epiphany sealer - Pentron Clinical Technologies, Wallingford, CT, USA) has been introduced. It is a dual curable thermoplastic synthetic resin material, is used with a self-etching primer to create a solid monoblock. ,
Resilon performs in a similar way to gutta percha, has the same handling properties, and can be heat softened or dissolved with solvents such as chloroform during retreatment procedures. A real seal/epiphany sealer is a dual-cure resin composite sealer, which is used in conjunction with Resilon points.  The Resilon System is expected to form a monoblock within the canal space, whereby the core (Resilon) is bonded to the sealer (Epiphany) and the resulting complex is bonded to the root dentine by the resin-based primer. Such a monoblock has been suggested to reduce bacterial ingress pathways and strengthen the root to some extent. 
The present study compared the fracture resistances of endodontically treated teeth obturated with AH26 - gutta-percha, Resilon-Epiphany using lateral and vertical obturation technique
| Materials and Methods|| |
A total of 75 single-rooted extracted human teeth were subjected for the study. The teeth were stored in normal saline solution until use. The teeth were immersed in 5% sodium hypochlorite for approximately 15 minutes to remove organic material from the root structure.
All the samples were de-coronated, and the coronal surfaces of the roots were prepared perpendicular to the long axis of the root with a high-speed handpiece and a multi-purpose bur using air water spray. The length of all the roots was prepared approximately 16 mm from the coronal surface to the apex of the root. The working length was established with size 15 K-file (Dentsply malliefer, Tulsa, OK), 0.5 to 1 mm short of the apical foramen. The 15 size K-file was passed through the apical foramen of the canal before and after instrumentation to ensure patency. A total of 15 ml of 1.25% sodium hypochlorite was used for irrigation during instrumentation; 5 ml of 17% EDTA rinses was used during and after instrumentation to remove the smear layer.
The instrumentation was performed using profile 4% taper nickel titanium rotary instruments to size 35 up to the working length. The root canals were dried with sterile paper points before filling.
The roots were divided randomly into five groups of 15 teeth each. The root canals of Group 1 specimen were obturated with AH 26 sealer and master gutta-percha cone of size 35 (4% taper) using lateral condensation method [Figure 1]. Root canals of Group 2 specimen were obturated with gutta percha cone of size 35 and AH26 Sealer using Vertical Condensation method. A back fill with E and Q plus (META BIOMED Co. Ltd., Osong BioValley, cheongweon-gun, chungbuk) was performed [Figure 2]. Root canals of Group 3 and Group 4 were treated with a self-etching primer (Epiphany primer; Pentron clinical technologies) after instrumentation. Excess primer was then removed with paper points. Roots were obturated with Resilon cone of size 35 (4% taper) and Epiphany sealer using lateral and vertical condensation methods, respectively. Backfill was performed with Resilon in an E and Q gun in root canals of Group 4. Root canals of Group 5 were not obturated and served as control.
All of the root canals were enlarged and obturated by only one operator. The root canal fillings were checked for their obturation quality using periapical radiographs. All roots were stored at 37°C in 100% humidity for 1 week to allow complete setting of the sealers.
All of the roots were mounted vertically in self-cure acrylic resin blocks exposing 8 mm of the coronal part. The acrylic blocks were placed on the lower plate of the Universal testing machine (Instron T-Series TINIUS OLSEN. Instron Corp. England, UK) [Figure 3]. The upper plate included a steel spherical tip with a diameter of 5 mm. The tip was lowered to contact the entire coronal surface of the roots and subjected to a gradually increasing force (1 mm/min), which was directed vertically parallel to the long axis of the roots. The force when the fracture occurred was recorded as Newtons.
| Results|| |
The means of fracture loads of the groups are listed in [Table 1] in Newtons. Higher mean of fracture was seen in the Group 3 (928.1N), followed by Group 4 (902.6N), Group 1 (773.3N), Group 2 (769.9N), and the weakest group was the instrumented un-filled control group (766.0N). Most of the specimen showed vertical fracture when subjected to mechanical testing. According to one-way ANOVA, there was significant difference among the experimental groups (P < 0.05). Post-hoc Tukey test [Table 2] was used to compare the individual groups. Significant difference was found between Group 1 and Group 3 (P = 0.04), Group 2 and Group 3 (P = 0.03), and Group 3 and Group 5 (P = 0.03), and results were not significant among other groups. Group 3 (Resilon + Epiphany using lateral condensation) showed highest mean fracture resistance than other groups.
|Table 1: Descriptive statistics of fracture resistance of five studied groups|
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| Discussion|| |
Root canal instrumentation is an unavoidable step in endodontic treatment. However, it is understood that as dentin is removed during the instrumentation phase, a weakening effect on the root is inevitable, in addition to the wedging forces of the spreader during lateral condensation or excessive dentin removal to facilitate pluggers for vertical condensation. Any material that can compensate for this weakening effect would be very useful. Gutta percha is gold standard in the root filling materials, but limitations of gutta-percha i.e. inability to reinforce endodontically treated roots and coronal microleakage have lead to the development of an alternative. ,
Johnson et al. recommended the use of adhesive sealers in the root canal system to reinforce the root-filled teeth. Comparative in vitro studies have been done for evaluation of root-strengthening effect of different root canal fillings. ,, Resin-based dental materials have been proposed to adhere the root canal dentin and, therefore, to reinforce an endodontically treated tooth. , Various studies were conducted to compare the bond strength of Resilon and gutta-percha with dentinal wall and its reinforcement of the root structure. It is suggested that use of Resilon showed stronger adhesion to dentinal walls when compared with gutta-percha. 
Schafer et al. and Teixeira et al. reported that dual-curing resin-based root canal sealers increased the fracture strength more than AH26.
In this study, 0.04 profile Ni-Ti rotary instruments were used for biomechanical preparation of the root canal. Singla et al.,  who found that canals instrumented with ProTaper F4 instruments showed maximum reduction in vertical root fracture resistance compared with other groups: (control uninstrumented group, hand instrumented .02 taper, Profile .04 taper, and Profile .06 taper instrumented).
The removal of smear layer was thought to be important for resin-based materials to form adhesion and thus increase the fracture strength.  The best composition suggested for removing smear layer was using sodium hypochlorite followed by EDTA.  We used these materials respectively before filling the canals. Irrigation was performed with 15 mL of 1.25% sodium hypochlorite between each instrument, and the smear layer was removed during and after instrumentation with 5 mL of 17% EDTA.
In the current study, all the obturated groups were significantly more resistant to fracture than instrumented unfilled groups. So, it was concluded that all the filling materials used in this study appeared to strengthen the instrumented roots and restore the teeth to resist fracture.
Present study with Resilon and epiphany sealer using lateral condensation method (group 3) to obturate the teeth showed highest mean fracture resistance than gutta-percha groups and the instrumented unobturated control group. This finding is in agreement with the previous study by Teixeira FB et al.,  Schafer et al.,  and Sinan et al.,  who reported that filling the canals with the new resin-based obturation material increased the in vitro resistance to fracture of endodontically treated single-canal extracted teeth when compared with standard gutta-percha techniques.
This reinforcing effect of Resilon groups might be related to the capacity of epiphany sealer to bond resin-based root canal filling material (Resilon) with dentin wall forming a 'monoblock' holding the tooth together and making it more resistance to fracture.
It is important to emphasize that these resin-based root canal filling materials are technique-sensitive, and it is difficult to compare the findings of this in-vitro study to clinical situation because the adhesion of Resilon system is affected by several factors; failure to completely remove the smear layer or sufficiently adapt the resinous sealer to root canal walls might interfere with its bonding in addition to the polymerization shrinkage of these resinous materials during setting, and it is also wise to consider the very high C-factor of root canals during polymerization of resinous endodontic sealers that may cause gaps along dentine/filling material interface. During photo-polymerization, the volume of monomer is significantly reduced, promoting enough shrinkage stresses to debond the material from dentine, thereby reducing adaptation and increasing microleakage. , All of that might interfere with the bonding of these materials to dentine walls minimizing its supporting effect. It is important to mention that Resilon obturation system does not have the same extensive evaluation that gutta-percha and conventional sealers do. Further clinical implications of these promising adhesive materials are needed to search for an effective method to reduce the fracture susceptibility of endodontically filled teeth.
| Conclusion|| |
Resilon-epiphany obturated roots using lateral condensation method showed higher fracture resistance when compared with gutta percha-AH 26 and control group on vertical loading.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]