Thermographic Effects of 445 nm Laser in Periodontal and Periapical Areas Ex Vivo

Abstract

The objective of the study was to evaluate heat transfer within periodontal and periapical tissues when exposed to a 445 nm diode laser operating in continuous-wave (c.w.) versus pulsed mode. Mandibular bovine anterior teeth were endodontically prepared, and posterior teeth were used for laser-assisted periodontal therapy. A 445 nm diode laser was irradiated on root canals (120 μm glass fiber) and periodontal pockets (320 μm glass fiber) for 30 s (n = 20) at 2W in c.w. and pulsed modes (15 Hz, 50% duty cycle) using non-initiated tips. The maximum temperature changes (in °C) and heat transfer in height (vertical surface temperature distribution) and width (lateral heat transfer) were captured using a thermographic infrared camera. Mean periodontal heat temperature changes (in °C) were 36.53 ± 10.32 (c.w.) and 22.32 ± 8.46 (pulsed). In the periapical areas, the temperature changes were 11.65 ± 4.46 and 7.74 ± 2.40, respectively. In the periodontal tissues, lateral heat transfer was 6.13 ± 0.85 mm in c.w. mode and 6.94 ± 1.03 mm in pulsed mode. In the periapical areas, lateral heat transfer was 4.11 ± 0.75 mm in c.w. mode and 3.59 ± 0.32 mm in pulsed mode. The vertical surface temperature distribution in periodontal tissues showed similar patterns to periapical areas with minimal difference in both modes. Within the limitations of this study, a 445 nm diode laser caused a higher temperature change in continuous waves and produced greater lateral heat transfer than vertical spread in periodontal and endodontic applications.

Received: 29 November 2025 | Revised: 28 February 2026 | Accepted: 25 March 2026

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

Data sharing is not applicable to this article as no new data were created or analyzed in this study.

Author Contribution Statement

Grace Kang: Writing – original draft, Writing – review & editing, Visualization. Jamie Wu: Investigation. Ghaedsharafi Yasamin: Validation, Investigation. Jiayue Han: Writing – original draft, Writing – review & editing, Visualization. Thomas Manders: Validation, Investigation, Writing – review & editing. Rafael Delgado-Ruiz: Software, Validations, Formal analysis, Resources, Data curation, Writing – review & editing. Georgios E. Romanos: Conceptualization, Methodology, Validation, Investigation, Resources, Writing – review & editing, Visualization, Supervision, Project administration.