Ablation of temporomandibular joint structures of a pig with a fibre-guided 308 nm excimer laser light--an in vitro investigation.
OBJECTIVE
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.


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.


CONCLUSIONS
The guidable 308 nm excimer laser light offers a combination of precise tissue ablation with only minimal thermal damage to the surrounding tissue.
Haffner
Cornelius
C
Department of Restorative Dentistry and Periodontology, Ludwig-Maximilians University, Munich, Germany. chaffner@dent.med.uni-muenchen.de
Folwaczny
Matthias
M
Hickel
Reinhard
R
Horch
Hans Henning
HH
D000818:Animals; D020679:Arthroscopes; D002244:Carbon; D002358:Cartilage, Articular / Q000473:pathology / Q000601:surgery; D004396:Coloring Agents; D004867:Equipment Design; D005152:Facial Muscles / Q000473:pathology / Q000601:surgery; D005336:Fiber Optic Technology / Q000295:instrumentation; D007091:Image Processing, Computer-Assisted; D053685:Laser Therapy / Q000295:instrumentation* / Q000379:methods; D007834:Lasers / Q000145:classification*; D009336:Necrosis; D013552:Swine; D013701:Temporal Bone / Q000473:pathology / Q000601:surgery; D013704:Temporomandibular Joint / Q000473:pathology / Q000601:surgery*; D019224:Temporomandibular Joint Disc / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
D004396:Coloring Agents; D002244:Carbon