A Comparative Study of the Efficacy of WaveOne and NeoEndo Retreatment File System for the Removal of Gutta Percha from the Root Canal.

BACKGROUND: Teeth with apical periodontitis that either persisted or developed after initial root canal treatment is most often indicated for retreatment procedure. The present study was conducted to compare the WaveOne and NeoEndo retreatment file system for the removal of gutta-percha from the root canal.
MATERIALS AND METHODS: Fifty extracted mandibular first premolars with single straight roots were divided into two groups, Group I-WaveOne and Group II-NeoEndo. All samples were scanned with cone-beam computed tomography after the root filling and retreatment procedures. The decrease in the volume of filling material after each retreatment protocol was measured.
RESULTS: The mean volume of gutta-percha in Group I before retreatment was 5.6 and in Group II was 5.3, after retreatment in Group I was 2.7, and in Group II was 4.2. The mean percentage reduction in Group I was 45.2% and in Group II was 23.8%. The difference was significant (P < 0.05).
CONCLUSION: Both systems failed to completely remove gutta-percha. WaveOne was significantly more effective than the NeoEndo retreatment system. Copyright:

INTRODUCTION

A procedure to remove root canal filling materials from the tooth, revise the shape, and obturate the canals; usually accomplished because the original treatment appears inadequate or has failed or because the root canal has been contaminated by prolonged exposure to the oral environment. This definition is very limited because it does not take into consideration all the situations where there is no previous filling material to be removed, nevertheless, the case is failing and needs to be “retreated.”[1]

The leading cause of posttreatment disease after root canal treatment is persistent secondary intraradicular infection.[2] Teeth with apical periodontitis that either persisted or developed after initial root canal treatment are most often indicated for retreatment procedures. Another most common indication for retreatment is failed root canal treatment due to incomplete cleaning and disinfection of root canals, inadequate filling of root canals (unfilled, overfilled, or incomplete filling), and unsatisfactory or untimely coronal tooth restoration.[3]

The use of rotary instruments could reduce the fatigue and time of endodontic retreatments in comparison with hand files. Rotary nickel–titanium instruments are efficient than hand files.[4] Advantages of rotary files are maintenance of canal shape and shorter working time, whereas disadvantages are the higher incidence of file fracture and more remaining filling material after retreatment. A single-file reciprocating technique utilizing unequal clockwise and counterclockwise angles is four times safer and almost three times faster than using multiple rotary files to achieve the same final shape.[5] The present study was conducted to compared WaveOne and NeoEndo retreatment file system for the removal of gutta-percha from the root canal.

MATERIALS AND METHODS

The present in vitro study comprised fifty extracted mandibular first premolars with single straight roots. Higher authorities were approached for obtaining consent for the study.

All tooth root canals were instrumented with the ProTaper system up to the F3 file and filled with gutta-percha and epoxy resin-based sealer using the cold lateral condensation technique. After 1 month, the samples were divided into two groups based on retreatment system used: Group I-WaveOne and Group II-NeoEndo. All samples were scanned with cone-beam computed tomography after the root filling and retreatment procedures. The decrease in the volume of filling material after each retreatment protocol was measured. The results were clubbed and entered in MS excel sheet for correct statistical inference where P value was set statistically significant <0.05.

RESULTS

Table 1 shows that each group comprised 25 teeth.

Table 1

Distribution of specimens

Groups	Group I	Group II
System	WaveOne	NeoEndo
Number	25	25

Table 2, Graph 1 shows that the mean volume of gutta-percha in Group I before retreatment was 5.6 and in Group 2 was 5.3, after retreatment in Group I was 2.7, and in Group II was 4.2. The difference was statistically significant (P < 0.05).

Table 2

Mean volume of gutta-percha before and after retreatment

Groups	Before	After	P
Group I	5.6	2.7	0.02
Group II	5.3	4.2	0.05

Graph 1

Mean volume of gutta-percha before and after retreatment

Table 3, Graph 2 shows that the mean percentage reduction in Group I was 45.2% and in Group II was 23.8%. The difference was statistically significant (P < 0.05).

Table 3

Percentage reduction in the volume of gutta-percha after retreatment

Groups	Percentage reduction	P
Group I	45.2	0.01
Group II	23.8

Graph 2

Percentage reduction in volume of gutta-percha after retreatment

DISCUSSION

Retreatment is common in endodontics. The clinical success of endodontic retreatment seems to depend on whether alterations in the natural course of the root canals were caused by previous root canal treatment.[6] Few authors related their outcomes to microbiological problems to discriminate root canal retreatment. The clinical rate of success of retreatment has been estimated to vary between 50% and 90%. The ultimate goal of nonsurgical root canal retreatment is to re-establish healthy periapical tissues. There are many causes of failure of initial endodontic therapy.[7] These include iatrogenic procedural error, untreated canal, canals that are poorly cleaned and obturated, complication of instrumentation (ledges, perforation, etc.) and overextension of root filling material and sometimes by self-styled expert. Such “failures” are most often caused by microorganisms that have either survived the conventional treatment procedures or invaded the root canal system at later stages through coronal leakage.[8] To combat the infection, the root canal has to be renegotiated using either an orthograde or a retrograde route of entry. The selection of retreatment procedures primarily has to be based on case-specific factors, such as the technical quality of the root filling and the personal evaluation of risks and monetary costs.[9]

There are different techniques currently in use for the removal of filling materials. These are the use of endodontic hand files, automated devices, solvents, ultrasonics, and lasers. Earlier endodontic retreatments were challenging as well as time-consuming.[10] The present study was conducted to compared WaveOne and NeoEndo retreatment file system for the removal of gutta-percha from the root canal.

In the present study, the mean volume of gutta-percha in Group I before retreatment was 5.6 and in Group II was 5.3, after retreatment in Group I was 2.7 and in Group II was 4.2. Wahane et al.[11] compared the NeoEndo and WaveOne retreatment systems concerning the effective removal of epoxy resin-based sealer and gutta-percha during the retreatment of straight root canals. Sixty extracted, human mandibular first premolars were randomly divided into two groups (n = 30) according to the retreatment system used: NeoEndo and WaveOne. There were no statistically significant differences in the initial filling volume of the filling material among the samples (P > 0.05). The amount of filling material in the root canals decreased after two retreatment protocols. However, none of the protocols succeeded in complete removal of the material from any root canal. The WaveOne system was more effective than the NeoEndo retreatment system during the removal of filling material.

We found that the mean percentage reduction in Group I was 45.2% and in Group II was 23.8%. The difference was statistically significant (P < 0.05). Sundqvist et al.[12] for example, reported an overall success rate of 74% of 50 cases examined after retreatment. They found that the success rate in bacteria-free canals was almost 80%; whereas in teeth with particular bacteria species the outcome was significantly lower (66%). In a study by Sjogren et al.[13] similar results were achieved and further considerations were made regarding the size of the lesions: The greater the lesion, the lower the success rate. During the diagnostic phase, only clinical signs and symptoms are available for dentists.

The removal of filling materials during retreatment procedures enables instruments and irrigants to reach all areas of the root canal system, which results in more effective intracanal cleaning and disinfection. According to a review, no existing retreatment protocol can completely remove root filling materials.[14] The mean percentage of residual material ranges from 45.4% to 0.02%. Kvist and Reit[15] compared the results of surgical and nonsurgical retreatment. After 1 year, the surgically treated cases had healed more quickly, but after 4 years the slower healing of the nonsurgical cases had “caught up” and there were some failures in the surgical group, resulting in no difference.

CONCLUSION

Authors found that both systems failed to completely remove gutta-percha. WaveOne was significantly more effective than the NeoEndo retreatment system.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.