The long-term retention of root canal treated teeth depends on many factors but it has become evident that the most common reasons for extraction of these teeth are ‘large carious lesion’ or ‘unrestorable tooth’, followed by ‘tooth fracture’, ‘periodontal disease’ and last of all, ‘endodontically related disease’ (Ng, Mann and Gulabivala, 2010).

Moreover, it is apparent that remaining structural integrity and the preservation of especially peri-cervical dentine are key factors that determine the long-term prognosis (relating to fracture resistance) in these teeth (Tang, Wu and Smales, 2010).