6.2
Restoration of an Endodontically Treated Posterior Tooth
Shanon Patel, Massimo Giovarruscio, and Bhavin Bhuva
Objectives
At the end of this case the reader should understand the biomechanical differences between endodontically treated teeth and vital teeth, and the principles of restoring endodontically treated posterior teeth.
Introduction
A 45‐year‐old patient presented with symptoms of a throbbing pain localised to a heavily restored upper left first premolar tooth (UL4).
Chief Complaint
The patient complained of a spontaneous throbbing ache that lasted minutes to hours. Hot and cold liquids also resulted in similar symptoms. The pain had been getting progressively worse over the last four days.
Medical History
Unremarkable.
Dental History
The patient regularly attended her dentist for annual routine examinations and saw the hygienist every six months.
Clinical Examination
The UL4 was restored with a class 2 amalgam restoration (Figure 6.2.1). The tooth was slightly tender to percussion. The patient’s presenting symptoms were reproduced with cold sensibility testing on the UL4. A periapical radiograph revealed a calcified pulp chamber and root canal system (Figure 6.2.2).
Diagnosis and Treatment Planning
A diagnosis of symptomatic irreversible pulpitis with symptomatic apical periodontitis was reached for the UL4. The patient was advised that endodontic treatment was necessary if she wished to retain her tooth, after which a cuspal coverage restoration (for example, crown or onlay) would be required to provide the best long‐term treatment outcome.
Before embarking on endodontic treatment, how would you assess the restorability of the tooth?
The overall restorability of the tooth must be established before carrying out endodontic treatment (Table 6.2.1). The following factors should be assessed:
- Periodontal status: The periodontal probing profile should be determined by ‘walking’ a periodontal probe around the circumference of the tooth. Localised increased probing depths may be of significance (for example, vertical fractures, furcation defects or perforation) and generalised increased probing depths indicating periodontal disease may adversely influence the long‐term prognosis of the tooth.
Table 6.2.1 Factors affecting the prognosis of a tooth requiring endodontic intervention.
General - Patient’s motivation to preserve tooth
- Financial and time restraints
Prosthodontic - Ability to remove existing restoration
- Remaining sound coronal tooth structure
- Ability to obtain ferrule
- Occlusal factors
- Ability to obtain satisfactory aesthetics
Periodontal - Oral hygiene
- Gingival health and periodontal probing depths
- Furcation involvement
- Root length and anatomy
Endodontic - Development status of root
- Existing root canal treatment
- Presence of a periapical radiolucent lesion
- Access to tooth
- Ability to isolate the tooth with dental dam
- Ability to identify all root canals
- Ability to negotiate, shape, clean and fill all canals to length
- Prosthodontic status: The residual sound tooth structure should be assessed following the removal of existing restorations and/or caries, after which the restorability of the tooth may be determined. The volume and location of residual sound dentine will determine the ‘survival’ of the endodontically treated tooth, as the majority of teeth will fail through ‘structural’ (biomechanical) failure, rather than due to complications associated with the root canal treatment itself. For endodontically treated posterior teeth, in addition to the overall loss in sound tooth structure, a minimum 2 mm of supramarginal circumferential sound coronal dentine is desirable to provide a ferrule effect for the subsequent cuspal coverage restoration (for example, crown or onlay). The final restoration therefore needs to be considered and planned following coronal disassembly.
- Endodontic status: Is it possible to identify and negotiate all the root canals to their full working length for subsequent preparation, cleaning and obturation? If these objectives can be met, then the endodontic prognosis of the tooth in question is excellent, regardless of whether the tooth is being root treated for the first time or being retreated.
These factors will determine the overall prognosis of the tooth. It is essential to advise patients that the tooth will need to be investigated in the first instance to establish the feasibility and prognosis of treatment. Prior to embarking on the treatment, it should be discussed that if there is insufficient tooth structure and/or a deep crack is found, then extraction may be indicated. Furthermore, the patient should be advised of the importance of the final cuspal coverage restoration as an integral part of the treatment.
How do endodontically treated teeth differ from vital teeth?
Endodontically treated teeth appear to be more susceptible to fracture compared with teeth with vital pulps. This is due to a cumulative effect of the following:
- Loss of tooth structure
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