Purpose: The present in vitro investigation was carried out to assess the efficacy of treatment with 308 nm excimer laser radiation applied to the structures of the temporomandibular joint of a pig. Laser parameters suitable to ensure adequate clinical efficiency with only minor thermal damage to the surrounding tissues were to be determined.
Material and methods: Tissue structures of the temporomandibular joint (cortical and cancellous bone, cartilage, disc and muscle) were extracted from freshly killed pigs and served as specimens. The specimens were embedded in polymethylmethacrylate. The laser light was applied after horizontal sectioning and measurement of thickness. The number of impulses that were necessary to perforate the specimen was counted and the rate of ablation determined. In addition, the irradiated surface was investigated histologically and the degree of tissue alteration was evaluated.
Results: The lowest energy threshold for ablation was found at an energy density of 0.8 J/cm2. Depending on the type of tissue, the maximum rate of ablation was evaluated as 1.7-6.3 microm/pulse. The depth of the thermal alteration to the surrounding tissue was about 30-70 microm.
Conclusion: The guidable 308 nm excimer laser light offers a combination of precise tissue ablation with only minimal thermal damage to the surrounding tissue.