Optimized Injectable Matrix Approach for Deep Margin Elevation in Challenging Subgingival Restorations: A Case Report

Abstract

This case report describes a modified deep margin elevation (DME) technique to address a deep subgingival carious lesion in Tooth 9 of a 62-year-old female patient with a history of bisphosphonate therapy and hypothyroidism. Conventional restorative techniques were inadequate because of the lesion’s subgingival depth. A customized injectable matrix technique was utilized, incorporating injectable wax, flowable composite, and soft tissue management with aluminum chloride–soaked retraction cord. The wax replicated the internal structure of the cavity, upon which a flowable composite was light-cured to form a patient-specific matrix. Glycerin gel was used to eliminate the oxygen-inhibited layer and facilitate matrix clearance. Composite resin was administered to raise the margin supragingivally, enhancing both periodontal and restorative results. This technique provides superior accuracy, clarity, and flexibility compared to conventional DME, particularly in anatomically complex cases.