A survey of methods used for post removal in specialist endodontic practice

[drsushant]

 

Introduction.

The most common reason for failure of root canal treatment is the presence of microorganisms within the root canal system (Nair et al. 1990, Sundqvist et al. 1998). When endodontic failure occurs, conservative orthograde retreatment is usually the preferred treatment choice rather than periapical surgery, since retreatment is generally more successful and more predictable (Allen et al. 1989).
Orthograde root canal retreatment requires removal of the existing coronal restoration in order to obtain access to the root canal system and this may include removal of a post. There is little information in the dental literature to indicate how often this is required, although Abbott (1994) analysed the treatment performed on 2000 patients referred to a specialist endodontist and reported that post removal was required for 210 teeth. This represented 9.4% of all teeth treated and 25.7% of the retreatment cases with the majority of posts being removed from maxillary incisors (60.9%).
Articles in the dental literature concerning post removal are mainly discussions of the various techniques for post removal in the form of clinical case presentations. Several techniques can be used to remove posts and these include the use of ultrasonic vibration, solvents with endodontic files, burs to drill the posts out, and post removal devices. Some examples of post removal devices are the Masserann kit (Micro-Méga, Besançon, France), the Eggler post remover (Automaton-Vertriebs-Gesellschaft, Germany), the Gonon post remover, which is also called the Thomas Extracteur De Pivots (FFDM, Bourges, France) and more recently, the Ruddle post remover (Analytic Endodontics, Orange, CA, USA).
In a survey of American endodontists regarding the methods used to remove posts, Stamos & Gutmann (1993) reported that the majority of respondents used haemostats (67%) or they drilled out the posts (62%). These figures are surprising, and somewhat alarming, particularly regarding the use of a bur to drill out a post. This procedure is very likely to lead to loss of a considerable amount of the surrounding dentine, which may result in root perforation or may weaken the tooth and predispose it to a vertical root fracture. The least common method for removing posts amongst the respondents was the use of post removal devices such as the Gonon post remover, the Eggler post remover and the endodontic extractor. Some respondents did not use post removers because they thought they were too dangerous, could not be used universally, or they did not work. Unfortunately, from the survey report, it was not possible to determine the method of post removal in different situations or whether more than one instrument was used to remove posts. Surgical treatment was performed in situations where the post could not be removed or if respondents felt that post removal might cause a root fracture. They were concerned about this, because it is often stated that root fracture may occur with post removal even though there is currently no evidence in the literature to support this empirical claim.
The aims of the current study were to establish the attitudes of endodontists in Australia and New Zealand toward the risk of root fracture when removing posts, and to assess which methods they commonly use to remove posts.

        

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 Materials and methods.

A survey of members of the Australian and New Zealand Academy of Endodontists (ANZAE) was conducted in April 1999. The survey was mailed to all 74 members of the ANZAE with an explanatory letter and a stamped pre-addressed return envelope. The survey was divided into three parts to obtain the following information:

1. Details of previous undergraduate and postgraduate training, number of years in specialist endodontic practice, number of h per week treating patients, and the practice location. 
2. An analysis of cases treated by the endodontists to determine the percentage of teeth that require root canal retreatment, the number of orthograde retreatment cases and the number of surgical cases treated each month. The attitudes toward the risk of root fracture during post removal were determined, as well as the treatment options considered for post removal and reasons for not removing a post. Each respondent was also asked to indicate whether they had ever fractured a root during post removal and to provide details of the case(s), if possible. 
3. Data were obtained about the post removal devices that were available in their practices and which ones they commonly used.

Periapical radiographs of four clinical examples (Figs 1–4) were provided to determine the methods used to remove posts in the following specific situations: a maxillary anterior tooth with a cast post and core, a maxillary anterior tooth with a parallel-sided preformed post, a mandibular molar with a parallel serrated preformed post, and a maxillary anterior tooth with a fractured parallel-sided preformed post.

Figures 1. A cast post and core in a maxillary incisor tooth. Respondents were asked to indicate the instruments they would use to remove this post or any other treatment that they would recommend.

The survey participants were advised to assume that root canal treatment was indicated because of the presence of symptoms and that there were no other complicating factors. They were asked to indicate their first and second choices for removing each post, and if post removal was not their preferred treatment, then they were asked to indicate what other treatment they would provide.

Figures 2. A parallel preformed post in a maxillary incisor tooth. Respondents were asked to indicate the instruments they would use to remove this post or any other treatment that they would recommend.

Figures 3. A parallel preformed post in a mandibular molar tooth. Respondents were asked to indicate the instruments they would use to remove this post or any other treatment that they would recommend.

Figures 4. A fractured post in a maxillary incisor tooth root. Respondents were asked to indicate the instruments they would use to remove this post or any other treatment that they would recommend.

Statistical analysis.
Data from the returned surveys were entered into a database statistical software program ( SPSS for Windows 6.1.31995, SPSS Inc, Chicago, IL, USA) for analysis. Chi-squared ( 2 ) tests were conducted from contingency tables of different variables where the sample was large. When the sample was not large and the expected value was less than five, the Fisher’s exact test was used. Statistical analysis was performed at the 95% level of confidence.

        

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Results:

There were 62 survey forms returned, which was a response rate of 84% of the ANZAE members. Retreatment of previously root-filled teeth constituted an average of 38% of all treatment performed by the respondents in their practices. The average number of root canal retreatments commenced each month was 27, with an average of three cases per month being treated surgically; the average number of posts removed each month was six. The majority of retreatment cases were treated by orthograde techniques and when a post was present in a tooth that required retreatment, 66% of respondents preferred to remove the posts, whilst 27% considered removing the post or considered doing periapical surgery. Of the respondents who considered post removal and periapical surgery, 75% were concerned that post removal may cause the roots to fracture. However, of those that preferred to remove the post, only 46% were concerned about root fracture.
Forty-seven per cent of the respondents indicated that they would avoid removing posts in certain situations and the most common reason was the presence of a wide post and the concern that the root may fracture. Some other common situations were when:

The coronal restoration was deemed clinically satisfactory, particularly in situations where the cost to replace the coronal restoration was high;
Removal of the restoration would result in the tooth being unrestorable;
The patient chose to have periapical surgery. There was no statistically significant difference in the use of post removal devices amongst respondents who reported avoiding post removal in certain situations ( 2 = 0.81, P = 0.37).

        

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