by Dr. Kamsiah G Haider BDS, MDS , Dr. Lehgabairavi Shanmuganathan BDS
Crowned teeth requiring retreatment due to fracture of the underlying tooth structure and/or foundation restoration often possess an undamaged extracoronal restoration. Rebuilding the core followed by making an impression for a new crown fabrication may be an option, but it is time-consuming and financially demanding.
In such cases, it may be desirable to reuse the intact restoration for the sake of cost and time. If the underlying root is healthy, the tooth is restored with a post and core followed by retrofitting the existing intact crown. This article describes the technique of refabricating post and core to match the features of the existing crown in restoring a damaged root filled tooth.
INTRODUCTION
A post-and-core followed by a crown is a common treatment option to restore the form, function, and aesthetics of an endodontically treated tooth. However, several clinical studies have shown the failure of these post-retained crowns. These studies indicate that endodontically treated teeth have a shorter survival time compared to that of a vital teeth.
Among the possible causes for endodontically treated teeth restored with post-retained restoration to face failures include loosening of the post, fracture of the post or root itself. Other documented post-and-core complications are recurrent caries, endodontic failure, periodontal disease, cement failure, post-core separation, crown-core separation, loss of crown retention, post distortion and tooth fracture.
Very often the post and core fails, leaving behind an intact crown. Root may have adequate bone support and which could be favourably used if the post is retrieved. Depending on the extent and severity of the fracture, retrofitting the crown on a fractured core may be a preferred option.
CLINICAL REPORT
A 43-year old female presented with a dislodged crown of the left maxillary molar and fractured post-and core restoration. Past dental history showed that the tooth was previously root canal treated and restored with a cast post and core followed by a Zirconia crown over it. On examination, both post-and-core was fractured leaving behind a healthy root and intact crown (Figure 1).
The residual cement in the post space was removed and a fibre post of diameter 1.25mm (Flexi-Post, Coltene Whaledent) was bonded using dual-cured composite resin (Paracore, Coltene Whaledent) (Figure 2). The crown was intact, and it was decided to be used to restore the fractured tooth. Fitted surface of the crown was first cleaned and dried. A 50 µm polytetrafluoroethylene (PTFE) (teflon) tape was adapted on the fitting surface of the crown and a dual-cured core build-up composite resin (Paracore, ColteneWhaledent) was injected into the crown and positioned over the bonded post. It was then light polymerized for 30s and excess composite was gently removed with a probe (Figure 3).
The crown was then removed leaving behind the core bonded to the post and the tooth structure (Figure 4). The core was light polymerized again for 30 s. The teflon tape was removed from the crown, and the crown was cemented to the core using glass ionomer cement (GIC gold label glass ionomer luting and lining cement) (Figure 5).
CONCLUSION
The need for retreatment of a tooth and/or prosthetic restoration may arise due to secondary caries, pulpal involvement, trauma to the restoration, and/or foundation, and subjective desires for a more aesthetic or durable restoration. Crowned teeth requiring retreatment due to fracture of the underlying tooth structure and/or foundation restoration often possess an undamaged extracoronal restoration. In such cases, it may be desirable to reuse the restoration for the sake of cost and time.
REFERENCES
- Arabolu. M., et al., 2014, Using an Existing Crown to Repair a Damaged Cast Post and Core Restoration, Journal of International Oral Health 2014; 6 (5):111-113.
- Saafi.J., et al., 2018, A Simplified Technique for Retrofitting a Post and Core Foundation to a Pre-existing Crown: A Case Report, J Dental Sci, , 3(2): 000171.