Uncertainty in Internal Matrix Selection During Apexification: A Case-based Critical Appraisal

Abstract

Background: Apexification in immature permanent teeth with open apices requires controlled placement of apical barrier materials to limit overextension and support an apical seal. Internal matrices may assist this procedure; however, their indications and material-selection criteria remain insufficiently defined. Case Presentation: A 22-year-old female patient presented with intermittent discomfort in tooth #21 and a history of dental trauma. Clinical and radiographic findings, including cone-beam computed tomography, indicated pulpal necrosis with symptomatic apical periodontitis, an immature apex, and a periapical radiolucency. After minimal canal preparation and intracanal calcium hydroxide medication, an amniotic membrane allograft was adapted as an internal matrix. A 4–5 mm mineral trioxide aggregate apical plug was placed, followed by thermoplasticised gutta-percha obturation and definitive coronal restoration. Discussion: The case is used to critically appraise internal matrix materials, including collagen scaffolds, calcium sulphate, platelet-rich fibrin, and amniotic membrane. Matrix selection appears to be influenced by apical morphology, lesion characteristics, material behaviour, radiographic visibility, operator experience, and practical considerations rather than standardised criteria. Conclusion: At six months, the tooth remained asymptomatic and showed radiographic and cone-beam computed tomographic evidence of reduced periapical radiolucency. The case illustrates the potential procedural role of an internal matrix in apexification, while highlighting the need for objective clinical criteria and comparative evidence to guide matrix selection.