5.2
Non‐surgical Retreatment and Disassembly
John Rhodes
Objectives
At the end of the case the reader should be aware of the assessment, treatment options and technical aspects of disassembling a tooth that has been restored with a post crown.
Introduction
A 54‐year‐old man was referred with occasional pain and tenderness over the apex of his root‐filled maxillary right lateral incisor (UR2). The tooth had been restored with a post crown for over 15 years.
Chief Complaint
A tender spot on the gum above the tooth and the tooth occasionally ached.
Medical History
Unremarkable.
Dental History
A regular attender at the dentist with a well‐maintained dentition.
Clinical Examination
There were no extraoral signs or swelling. Intraoral examination revealed a well‐cared‐for dentition with various restorations, no caries and healthy periodontium.
The crown on UR2 was reasonable and there was staining on the UR1 and UR3
(Figure 5.2.1). The gingiva was tender when palpated over the apex of UR2.
What does the periapical radiograph reveal?
- Alveolar bone height within normal limits.
- The UR2 had been restored with a post crown and large metal parallel serrated or screw post that extended 2–3 mm below crestal bone level.
- A laterally condensed gutta percha root filling was in place; the filling could be slightly short.
- There was a periapical radiolucency associated with the UR2.
- The UR1 had also been root filled more recently and there may be periapical radiolucency associated with this tooth (Figure 5.2.2).
A small‐volume cone beam computed tomography (CBCT) scan of the anterior maxilla was exposed to confirm the presence or absence of periapical pathology on the UR1 and to prepare for the possibility of a microsurgical treatment approach on the UR2 (Figure 5.2.3).
The CBCT showed:
- There was no periapical radiolucency associated with the UR1.
- A periapical radiolucency was evident on the UR2. The cortical plate was intact.
- There were no other problems identified.
Diagnosis and Treatment Planning
The diagnosis for the UR2 was symptomatic apical periodontitis associated with an existing root canal treatment.
Treatment options for tooth UR2
- Non‐surgical root canal retreatment
- Microsurgical root end surgery
- Extraction and replacement
- No treatment
Technical challenges
What technical challenges could be faced during treatment?
Non‐surgical retreatment will require the removal of the large metal post. Using force there is a risk that the root could fracture while this is being done. The tooth would definitely require a new coronal restoration for which the patient would incur additional cost.
Microsurgical treatment avoids the need to replace the crown and has a similar success rate in the short term to a non‐surgical approach. However, there is more risk of postoperative pain and swelling.
The general consensus is that if the previous root filling is technically poor and can be improved using a non‐surgical approach, this will improve the long‐term prognosis. However, in anterior teeth with post crowns, if the post crown restoration is good it is often possible to disinfect the apical portion of the root beyond the post using a modern microsurgical approach and bespoke ultrasonic instruments.
The tooth is restorable and functional and it would be difficult to justify extraction and replacement. Equally, doing nothing risks the chance of an acute flare‐up.
Treatment plan
After discussing all of the options the patient elected to have non‐surgical root canal retreatment.
Single‐ or multiple‐visit treatment?
Due to the concern that a temporary post crown could allow microleakage between visits, there was no clinical justification for completing treatment over two visits. In this case, due to the possibility of contamination with multiple‐visit treatment, single‐visit treatment may be associated with a higher chance of success.
Treatment
After application of local anaesthetic, the crown on the UR2 was removed by sectioning and elevated with an Ash crown remover (Dentsply Sirona, Charlotte, NC, USA).
The root was isolated with dental dam and a wingless EW clamp (Ash, Denstply Sirona) (Figure 5.2.4).
Disassembly
Core material was removed from around the metal post using a Start‐X no. 3 ultrasonic tip (Dentsply Sirona) on a medium power setting. Cement was removed from around the post using the same ultrasonic tip (Figure 5.2.5).
Post removal – what is the most efficient means?
- Cement should be removed conservatively to preserve valuable coronal tooth substance. This can be achieved with ultrasonic tips and when the post is cylindrical with a Masserann trephine.
- Ultrasonic tips can be used to vibrate and loosen metal and cast restorations. Heat is created when using ultrasound and it is important to use water coolant to prevent damage to the periodontium.
- Do not try to remove the post with forceps or apply lateral force, as this will increase the likelihood of root fracture.
- If after a few minutes nothing seems to be happening, consider using a different technique such as a post‐puller.
The post was removed using a combination of a Masserann trephine and a Start‐X no. 4 ultrasonic tip. The tip was used with water coolant to prevent heating. The Masserann trephine was used to remove cement conservatively from around the circumference of the post. It can also be used to grip the post and help unscrew it (Figure 5.2.6).
Gutta percha root filling material was removed using a Gates‐Glidden no. 2 and Hedström file no. 30.
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