Perforation management and primary endodontic treatment

Dr Petros Mylonas, Clinical Lecturer and Speciality Training Registrar in Restorative Dentistry, presents a challenging case, consisting of perforation repair, canal location, and primary root canal treatment (RCT).

Patient information

An 80-year-old female presented to Cardiff Dental Hospital Restorative Department consultant clinic in November 2022. The patient was experiencing occasional pain from the UR2. Previous acute pain in the same tooth had led to RCT in May 2022 by her general dental practitioner (GDP). An iatrogenic perforation had occurred at this time. The UR2 was dressed temporarily before her referral to Cardiff Dental Hospital.

The patient was a regular attender with good oral hygiene. Her medical history revealed hypothyroidism, previous deep vein thrombosis, and crepitus associated with her right-hand side temporomandibular joint on opening.

Assessment

The patient experienced sharp pain followed by a dull throb, particularly when she bit down hard. In addition, a temperature-sensitive shooting pain was noted in the UR2 region.

A thick gingival biotype was identified, with no swellings or pathology, some recession generally, and periodontal assessment scores of 3/3/3, 3/3/3. The dentition was heavily restored, but there was no evidence of caries or other primary hard tissue disease. Assessment of the UR2 revealed a positive response to percussion testing, buccal tenderness, no probing depths over 5mm, positive response to sensibility testing, and grade 0 mobility.

An intraoral periapical radiograph revealed normal bone levels, temporary restoration in the UR2, and a veneer on the UR1. Radiolucency was identified distally on the UR2. The root canal of the UR2 was not clearly visible at the apical 1/3, and the periodontal ligament was intact.

Diagnoses

A diagnosis of generalised periodontitis (stage 2, grade A) with unknown stability was determined, alongside previously initiated therapy with a symptomatic apical periodontitis, and distal perforation for the UR2.

Treatment options

Four treatment options were discussed:

1. No treatment and monitor (not recommended)
2. Non-surgical perforation repair and orthograde RCT
3. Surgical perforation repair and orthograde RCT
4. Tooth extraction and prosthetic provision

The patient consented to option two, but understood that options three and four were distinct possibilities and provided consent for these too, if necessary.

Treatment plan

The treatment plan for the UR2 was as follows:

• Restorability assessment following the removal of the existing temporary restoration
• Visualisation of perforation, and determination whether perforation can be located externally
• Consider cone beam computed tomography (CBCT) evaluation if clinical assessment of the perforation is inconclusive
• Determine whether perforation is supra- or sub-crestal
• Attempt non-surgical repair
• If successful, continue with orthograde RCT
• If unsuccessful, carry out surgical repair – then continue with orthograde RCT

Further evaluation of the periodontal condition, stabilisation, and management of periodontal disease, to be provided by her GDP.

Treatment provision

Visit 1 – Restorability assessment, perforation location, true canal location.

The temporary composite restoration with cotton pledget and Ledermix was removed, caries was removed, and the true root canal was visualised. This was done without dental dam to ensure visualisation of the crown axis and aid bur angulation. The UR2 and 1, UL1 and 2 were then isolated with dental dam using Wedjets and floss ties. The perforation site was thoroughly debrided with sterile saline, and dried gently with an ISO 70 paper point.

There was no communication between buccal mucosa and the UR2 perforation, though some granulation tissue was evident, and the angulation of perforation appeared to track distobuccally. The true root canal had a working length of 22mm.

The perforation had an ISO of >70 in diameter, and it was difficult to know the precise shape or whether it was supra- or sub-crestal. As such, further radiographic assessment was required – a high resolution, low field of view CBCT of the UR2 (5x5cm) – to visualise the perforation shape, position, size, extent, and whether it was supra- or sub-crestal.

Visit 2 – Discussion of CBCT results with patient and finalisation of treatment strategy.

CBCT review revealed the UR2 had an access cavity which tracked the long axis of the clinical crown, but did not match the angulation of the root. The crown axis and root axis did not align.

The CBCT also showed that the perforation tracked distobuccally, with dimensions similar to a tapered diamond dental bur. The distal aspect was approximately 2mm in length, and width varied from 5mm to 1mm corono-apically. The perforation had an irregular shape, and was entirely supra-crestal. It was agreed with the patient to attempt non-surgical repair of the perforation using resin-modified glass ionomer (Vitrebond) and continue with primary endodontic treatment.

Visit 3 – Controlling the main canal and stage one of perforation repair.

The main root canal orifice was accessed, and coronal preparation completed to ensure ease of access for future primary RCT. The perforation site was thoroughly cleaned with a 50:50 ratio of 2% NaOCl and sterile saline. Granulation tissue was removed with a gooseneck bur, the site was temporised with non-setting calcium hydroxide paste, and a cotton pledget and Poly-F temporary restoration was provided to allow resolution of bleeding and facilitate perforation repair at the next visit.

Visit 4 – Completion of perforation repair and primary RCT.

After the removal of the temporary restoration and irrigation of both the main root canal and perforation, the main canal was blocked with a large Polytetrafluoroethylene (PTFE) barrier. The perforation site was gently cleaned with 50:50 2% NaOCl and saline mixture and dried with micro-suction and size 70 paper points. The repair was carried out carefully using Vitrebond glass ionomer and a modified injection technique. An intraoral periapical radiograph was taken to confirm restoration.

Following this, a Reciproc Blue R25 file was used for canal shaping, the site was irrigated with full strength 2% NaOCl, and activated with EndoActivator. Obturation was performed using gutta percha and AH+ sealer, with a warm vertical condensation technique, to a length of 22mm.

Visit 5 – First review at six months.

At a six-month review, there were no clinical symptoms relating to the UR2, indicating the need for surgery would be unlikely in the near future.

Visit 6 – One-year review.

At a 12-month review, there were still no signs or symptoms, and there were no radiographic features evident. Patient was discharged for continued monitoring by the GDP.

Case reflection

This was a difficult case due to the location and size of the perforation. CBCT imaging allowed the complete 3D visualisation of the perforation – it supplemented clinical assessment findings, and informed treatment planning including material selection and repair strategy.

A minimally invasive approach was undertaken with chemomechanical shaping of the main canal to preserve pericervical dentine and minimise risk of communication with the perforation.

Use of Vitrebond allowed for controlled restoration of the perforation with a moisture tolerant material indicated in similar situations.

Reason for iatrogenic perforation: the UR2 had a mismatch in axis/angulation between the clinical crown and the root. The root mesially inclined far more than expected from the clinical crown visible.

Tips to avoid perforation:

• Appreciation of visible clinical crown with consideration of position and contour of tooth structure at the level of cemento-enamel junction
• Assessment of crown/root angulation radiographically
• Careful planning of access cavity according to approximation of orifice location – remember centrality and concentricity as described by Krasner & Rankow (2004)[i]
• Use of magnification and illumination allowing visualisation of colour changes on pulp chamber floor
• Periodic radiographs to check your access angulation when there is clinical uncertainty

For more information about the BES, or to join, please visit the website www.britishendodonticsociety.org.uk or call 01494 581542

[i] Krasner, P., & Rankow, H. J. (2004). Anatomy of the pulp-chamber floor. Journal of endodontics, 30(1), 5–16. https://doi.org/10.1097/00004770-200401000-00002

Case Study Images:

Radiographic assessment Clinical assessmentRemoval of temporary restorationDebridement of perforation site Working length CBCT Perforation repair and root canal treatment Perforation repair and root canal treatment Root canal treatment completion12 month review appointment