The European Society of Endodontology and the American Association for Endodontists have released position statements and clinical considerations for regenerative endodontics. There is increasing literature on this field since the initial reports of Iwaya et al. (Dental Traumatology, 17, 2001, 185) and Banchs & Trope (Journal of Endodontics, 30, 2004, 196). Endogenous stem cells from an induced periapical bleeding and scaffolds using blood clot, platelet rich plasma or platelet-rich fibrin have been utilized in regenerative endodontics. This approach has been described as a 'paradigm shift' and considered the first treatment option for immature teeth with pulp necrosis. There are three treatment outcomes of regenerative endodontics; (i) resolution of clinical signs and symptoms; (ii) further root maturation; and (iii) return of neurogenesis. It is known that results are variable for these objectives, and true regeneration of the pulp/dentine complex is not achieved. Repair derived primarily from the periodontal and osseous tissues has been shown histologically. It is hoped that with the concept of tissue engineering, namely stem cells, scaffolds and signalling molecules, that true pulp regeneration is an achievable goal. This review discusses current knowledge as well as future directions for regenerative endodontics. Patient-centred outcomes such as tooth discolouration and possibly more appointments with the potential for adverse effects needs to be discussed with patients and parents. Based on the classification of Cvek (Endodontics and Dental Traumatology, 8, 1992, 45), it is proposed that regenerative endodontics should be considered for teeth with incomplete root formation although teeth with near or complete root formation may be more suited for conventional endodontic therapy or MTA barrier techniques. However, much is still not known about clinical and biological aspects of regenerative endodontics.

A 47-year-old woman was referred by her general dentist to the postgraduate endodontic clinic for assessment and root canal treatment of multiple teeth with associated periapical radiolucencies. The patient's medical history included chronic renal failure. All mandibular teeth with periapical radiolucencies except tooth 37 had positive responses to pulp sensibility testing. A diagnosis of pulpal necrosis and associated periapical periodontitis was made on tooth 37, and root canal treatment was carried out. To determine the possible relationship between the patient's renal disease and the multiple periapical radiolucencies, an additional physician consultation and laboratory tests were requested. Secondary hyperparathyroidism was confirmed with the laboratory report showing an elevated level of parathyroid hormone and a normal serum calcium level. Renal osteodystrophy of the mandible caused by secondary hyperparathyroidism was the probable aetiology of the multiple mandibular periapical radiolucencies, and no root canal treatment was required. Key learning points Renal osteodystrophy of the mandible caused by secondary hyperparathyroidism can present as multiple periapical radiolucencies but is a rare finding. Diverse orofacial manifestations such as loss of lamina dura, widening of periodontal ligament and demineralization of bone can be observed in renal osteodystrophy. Thorough clinical and radiographic assessment along with the review of patient's medical history and haematological analysis is essential for the diagnosis of renal osteodystrophy.