Intraoral perfusion assessment using endoscopic hyperspectral imaging (EHSI)- first description of a novel approach.

Abstract

Objectives: This study aimed to establish a method to detect and quantify mucosal malperfusion intraorally using state-of-the-art Endoscopic Hyperspectral Imaging (EHSI). For this purpose, mucosal ischemia was selectively induced by intraligamentary anesthesia (ILA) with and without + epinephrine using a standardized protocol.

Materials and methods: EHSI was performed using a novel endoscopic hyperspectral imaging system. Parameters assessed were Tissue Oxygen Saturation (StO₂ [%]), Tissue Hemoglobin Index (THI), Near Infrared Perfusion Index (NPI) and Tissue Water Index (TWI). Fifty-seven healthy subjects received ILA using Articaine 4% with (ILA+) and without (ILA-) epinephrine at a dosage of 1:200,000 administered mesially and distally to the target tooth 42 (Universal No. 26). Mucosal perfusion was assessed using EHSI for 45 min post-injection.

Results: After ILA+, a distinct ischemia of the mucosa was already clinically apparent after 30 s with significant reduction of THI and StO₂ by an average of 57% (p < 0.001) and 7% (p < 0.040) compared to baseline values. Persistent hypoperfusion of the oral mucosa was observed throughout the monitoring period, exhibiting a gradual resolution at the 30-minute mark, and nearing baseline perfusion approximately 45 min post-injection. There was no papillary necrosis after ILA + injection.

Conclusion: EHSI is suitable to adequately detect and visualize actual perfusion of the intraoral mucosa. The study revealed that LA with epinephrine (1:200,000) induce temporary hypoxia in the dental papilla but without causing severe ischemia.

Clinical relevance: EHSI will enable promising applications in the future, i.a. success monitoring of periodontal therapies, intraoral free flap monitoring and the assessment of cancer margins.