Clinical and Radiographic Outcomes of Metronidazole Monotherapy in Regenerative Endodontics: A Case Series.

The evolution from apexification to regenerative endodontic procedures reflects a paradigm centred on preservation of the apical stem cell niche as a prerequisite for restoration of the pulp-dentine complex. This case series explores the biological premise in 6 immature mandibular second premolars diagnosed with pulp necrosis and chronic apical pathology secondary to fractured Leong's tubercles. Management employed a tissue-preserving regenerative protocol characterised by minimal mechanical instrumentation and metronidazole monotherapy as the sole intracanal antimicrobial agent. Following canal disinfection, controlled apical bleeding was induced to establish an endogenous cell-rich scaffold, and coronal sealing was achieved using bioceramic and adhesive restorative materials. Over follow-up intervals ranging from 9 months to 9.5 years, all teeth demonstrated resolution of periapical pathology, continued root maturation, apical closure and radicular wall reinforcement. Four teeth regained pulp sensibility, suggesting possible neurovascular regeneration. No reinfection or structural compromise was observed. Metronidazole monotherapy was associated with favourable clinical and radiographic outcomes while promoting biologically favourable regenerative outcomes, offering a reproducible, cost-efficient alternative to conventional multi-antibiotic protocols and reinforcing the feasibility of this monotherapy approach in regenerative endodontics.