First clinical application of a liquid-core light guide connected to an Er:YAG laser for oral treatment of leukoplakia.
ABSTRACT For medical applications, erbium lasers are usually equipped with articulated mirror arms or special glass fibers. However, only with mirror arms is it so far possible to transmit high average powers or pulse energies in the region of 1 J to achieve suitable energy densities for fast tissue preparation. An alternative to the glass fiber systems mentioned above are liquid-core light guides. An extremely flexible liquid-core light guide was used to connect a dental Er:YAG laser system to an especially adapted dental laser applicator. The core liquid was continuously circulated during laser irradiation to transmit pulse energies up to 1.1 J. A modified laser handpiece was used for exemplary clinical treatment. The experimental setup with the highly flexible light guide was completed successfully, and its ease of handling for a dental surgeon was demonstrated in the clinical treatment of leukoplakia of the oral cheek mucosa. Complete ablation of the epithelium with the laser was performed. One year postoperatively, the patient remains disease-free. This article describes the technical realization of a liquid-core light guide system for medical applications. We report about the first successful clinical treatment of oral hyperkeratosis using this new light guide technology.
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ABSTRACT: Laser therapy has been a favoured treatment regime for oral leukoplakia since the mid 1980s. There is no information in the literature regarding factors affecting outcomes in patients with oral leukoplakia. Forty-three patients (mean age 60.3+/-13.6 years) with 73 primary oral leukoplakia were assessed for outcome and factors affecting survival. Dysplastic lesions were found in the majority of patients. The male to female ratio was 1.7:1 with 74% ex- or current smokers, 27% consuming alcohol and 31% continuing to smoke after treatment. The mean observation time was 47.2+/-28.2 months (range 2-102 months). Disease-free survival was 55.4% at 3 years that dropped to 33.9% after 5 years. The malignant transformation rate was 7.3%. No significant prognostic factors were found on univariate analysis but alcohol consumption (P=0.034) and previous malignancy (P=0.018) were found to be significant prognostic indicators using multivariate analysis. Continuation to smoke approached significance (P=0.061). Similar disease-free survival and malignant transformation rates with minimal complications were found as compared to the literature. Recommendations for minimizing recurrence are presented. Long-term follow up and removal of aetiological factors, such as smoking and alcohol, are advised.International Journal of Oral and Maxillofacial Surgery 07/2005; 34(4):396-400. · 1.52 Impact Factor
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ABSTRACT: The ablation efficiency and depth of secondary thermal damage have been determined for a range of cadaveric soft tissues on exposure to radiation from a pulsed Er-YAG laser operating at 2.94m. The tissues investigated included brain, small intestine, stomach, liver, heart, spleen, lung, aorta, cornea, kidney, skin and uterus. The results obtained are compared to those predicted by a simple one-dimensional model of the interaction. The amount of tissue damage varied between tissues. In cellular tissues it was approximately 20m in extent on either side of the slot and at its base. In acellular tissues (aorta, cornea, etc.) the alteration in protein structure was more variable and was dependent upon the nature of the connective tissue fibres. Corneal collagen showed changes in protein structure up to 30m from the edge of the slot, whereas aortic elastic fibres were little affected by the laser energy, apparently melting to form a coagulum that lined the slot.Lasers in Medical Science 05/1991; 6(2):125-131. · 2.40 Impact Factor
- Applied Physics B 09/1997; 65(4):659-666. · 1.78 Impact Factor