Dr Nicolai Orsteen is a Specialist in Endodontics. Nicolai graduated from the dental school at the University of Oslo in February 2002, going on to study for a further three years, specialising in endodontics. Dr Orsteen has been working in private dental clinics in Oslo and London since 2002 and enjoys the challenge of difficult root canal cases. Since 2017 he has been the principal dentist at the Root Canal Dental Referral Centre in Richmond, London, which is a private practice solely limited to endodontics. See www.rootcanalcentre.co.uk for more information.
Here, Dr Orsteen describes a challenging case in which he performed root canal treatment (RCT) on a patient’s UL7, which had been restored with a full metal crown. The case was complicated by a calcified and curved canal.
Patient background
The patient – male, with generally good oral and physical health – attended the practice in October 2024, having been referred by his dentist for assessment. He was originally seen in January 2024 with some pain associated with his UL7. The tooth had been restored with a permanent non-precious metal crown that his dentist was unable to remove.
Assessment and diagnosis
Assessment and diagnosisThe restored UL7 was tender on percussion, and the tooth was hypersensitive to an ice test using ROEKO Endo-Frost (COLTENE). The neighbouring teeth had a positive response to the ice test within the normal limits.
Periapical radiographs showed some calcification, and there was significant curvature of the distobuccal canal – the mesiobuccal canal was also curved but not as acutely. There was no apical radiolucency, and the UL7 was diagnosed with symptomatic, irreversible pulpitis.
Treatment planning
All potential treatment options were explained to the patient. The tooth could be extracted and replaced with an implant; the tooth could be extracted and the patient could be left with a gap; the crown could be removed, and RCT be undertaken, and a new crown could be fitted by his regular GDP; or we could do nothing, which was not recommended in this case.
It was assessed that despite the complicating factors, RCT treatment had a very high probability of success: the prognosis was 90% for 5-10 years. The patient provided informed consent for this treatment.
Treatment provision
Treatment was performed 17 days after the assessment and consultation.
The efficacy of the local anaesthetic was confirmed using the ROEKO Endo-Frost, and a HySolate Latex Dental Dam (COLTENE) was used to isolate the tooth. The metal crown was cut into sections, which was difficult due to the durability of the material. Extreme precision and care had to be exercised to avoid any damage to the tooth structure. Upon removal of the crown, it was discovered that there was a great deal of decay under the metal that extended into the tooth and the pulp. However, the tooth was deemed restorable.
Working length was established with radiographs and by the use of the integrated apex locator in the CanalPro X Move endo motor (COLTENE) and the canals were irrigated using CanalPro NaOCl 3% and CanalPro EDTA 17% solutions (COLTENE).
The HyFlex OGSF file sequence (COLTENE), consisting of an Orifice Opener, Glidepath File, Shaping File and Finishing File were employed, with irrigation between each file. Once the tooth was opened, MicroMega K-Files and the Glidepath File were used to reach the root apex. Then, shaping files were used to carefully clean the canals.
Magnification supported the process of navigating the calcification, and I used flexible files to adapt to the curvature of the canals, and to reduce the risk of file separation. The root canal treatment was completed with the Finishing file (30.04).
Once the treatment was complete, the canals were sealed using gutta percha and bioceramic sealer. The core was built up using ParaCore White (COLTENE), and a temporary crown made of Cool Temp NATURAL (COLTENE) was cemented with the use of Temposil2 (COLTENE).
Treatment outcome
The patient and I were both happy with the treatment result. The tooth was saved and is asymptomatic. It was subsequently successfully restored with a permanent crown by the patient’s dentist.
Learning points
The combined challenges of apical curvature, calcification and significant tissue loss necessitated a cautious, conservative approach. Such a serious loss of dental hard tissue at the crown decreases fracture resistance and can compromise the bonding surface.[i]
In addition, calcification and curvature both pose a risk to the success of RCT. Challenges such as difficulty in achieving patency in the apical third, uneven dentine removal causing transportation, perforation, and instrument fracture within curved canals can pose significant procedural issues that may compromise the management of intraradicular infections and lead to unsatisfactory treatment results.[ii]
With so many elements to consider it was important to adopt a conservative approach to try to preserve as much of the tooth as possible. However, this required skill and careful selection of tools and materials.
In such cases, I recommend using a conservative taper. The files in the COLTENE Hyflex OGSF file sequence can be pre-curved, and are nickel-titanium (Ni-Ti), which has been shown to improve success rates in cases of curvature.ii Using these I was able to employ a precise approach to remove the infection without compromising the healthy tissue to reduce the risk of root fracture in the future.
For more information, info.uk@coltene.com and 0800 254 5115
COLTENE website https://www.coltene.com/
[i] Huang, D., Wang, X., Liang, J. et al. Expert consensus on difficulty assessment of endodontic therapy. Int J Oral Sci 16, 22 (2024). https://doi.org/10.1038/s41368-024-00285-0
[ii] Chaniotis, A. & Ordinola-Zapata, R. (2022) Present status and future directions: Management of curved and calcified root canals. International Endodontic Journal, 55(Suppl. 3), 656–684. Available from: https://doi.org/10.1111/iej.13685
