ISSN:1044-5471    

DOI:10.1089/clm.1997.15.1

年代:1997

数据来源: MAL

摘要:

ABSTRACTAnin vitrostudy of laser tissue welding mediated with a dye-enhanced protein solder was performed. Freshly harvested sections of porcine aorta were used for the experiments. Arteriotomies approximately 4 mm in length were treated using an 805 nm continuous-wave diode laser coupled to a 1-mm diameter fiber. Temperature histories of the surface of the weld site were obtained using a fiberoptic-based infrared thermometer. The experimental effort was complemented by the LATIS (LAser-TISsue) computer code, which numerically simulates the exposure of tissue to near-infrared radiation using coupled Monte Carlo, thermal transport, and mass transport models. Comparison of the experimental and simulated thermal results shows that the inclusion of water transport and evaporative losses in the model is necessary to determine the thermal distributions and hydration state in the tissue. The hydration state of the weld site was correlated with the acute weld strength.

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.3

年代:1997

数据来源: MAL

摘要:

ABSTRACTRoot resection of extracted human teeth was performed using the erbium:YAG (Er:YAG) and holmium:YAG (Ho:YAG) laser to investigate the clinical application of lasers on hard tissue. The CO2laser and the mechanical drill were also used for comparison. After resection using these technologies, the morphological changes of the cut surface were investigated by optical and scanning electron microscope. Er:YAG laser irradiation produced smooth, clean resected surfaces without signs of thermal damages. Complete obturation of the root canal was maintained after Er:YAG laser irradiation. Ho:YAG laser irradiation, however, produced some signs of thermal damage. Relatively large voids between the gutta-percha and the canal walls were revealed after Ho:YAG laser irradiation. The sealing of the dentinal tubules was not completely attained as stipulated by original conditions of this study.

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.9

年代:1997

数据来源: MAL

摘要:

ABSTRACTA new experimental therapy for squamous carcinoma was tested by sensitizing human tumor cells with light-sensitive anticancer drugs followed by laser illumination at visible or infrared wavelengths. The anthrapyrazole DUP-941 and the isoquinoline derivative DUP-840 were compared with the dianthraquinone hypericin. P3 human squamous carcinoma cells were incubated for 2 h with the drugs at escalating doses ranging from 5 to 100 μg/ml, then exposed to visible green 532-nm or infrared 1064-nm light at 300 J output from a KTP/Nd:YAG laser. Tumor cell toxicity measured byin vitroMTT viability assays was minimal after DUP-840 uptake but was slightly enhanced by infrared laser emissions. By contrast, the strong tumoricidal effects seen after DUP-941 uptake were amplified over 10-fold by 532-nm light and up to 2-fold by 1064-nm light. Hypericin-sensitized tumor cells were killed after 532 nm irradiation even at the lowest drug dose but were not affected by 1064-nm illumination. The results suggest that laser chemotherapy with drugs sensitive to photothermal energy could become a useful new treatment modality for cancer

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.15

年代:1997

数据来源: MAL

摘要:

ABSTRACTBackground/Objective: A new pulsed near-infrared laser was developed for incision of soft tissues. This article presents a preliminary investigation of the 1.44-μm laser.Methods: A prototype laser was used with a cleaved 600-μm quartz fiber (1.44 μm, 5–30 Hz, 30 W max.). Standardized 5-cm incisions were made on skin, striated muscle, and liver in anesthetized New Zealand White rabbits. The animals were euthanized and the tissues were immediately harvested, and histologic examination completed after hematoxylin and eosin (HE) staining. The acute zone of coagulation was measured. A wound healing study was conducted on anesthetized NZW rabbits. The hind leg muscle was exposed and four, 5-cm incisions were made using the laser (0.5 J, 25 Hz) and four incisions were made with an electrosurgical unit on coagulating current (25 W). The incisions were marked and the overlying skin reapproximated. One rabbit was euthanized on day 11 and one on day 21. The wounds were exposed and excised for histology.Results: The acute zone of injury was 1160 ± 120 μm to 1250 ± 110 μm for skin; 70 ± 20 μm to 400 ± 280 μm for muscle, and 660 ± 120 μm to 1930 ± 300 μm for liver. The chronic study demonstrated less inflammation in the laser wounds on day 11 and a chronic inflammatory response on day 21. No gross differences in healing were noted.Discussion/Conclusion: The 1.44 μm laser wavelength interacts with tissues in a manner that is substantially equivalent to the holmium laser (2.1 μm). Further studies of the 1.44 μm laser and delivery system develo

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.23

年代:1997

数据来源: MAL

摘要:

ABSTRACTThe microbial flora of the root canal dentin can cause failures in the conventional treatment of infected root canals if it cannot be sufficiently removed by preparation and chemical disinfection of the root canal. The aim of this study is to examine the bactericidal effects of neodymium:y ttriumaluminum garnet (Nd:YAG) laser irradiation in the depth of the root canal dentin. Following sterilization, longitudinal section dentin slices of different thicknesses (100–1000 μm) were inoculated on one side with 4 μl of aStreptococcus mutanssuspension. The opposite sides of the dentin slices were then irradiated four times for 10–20 sec (according to the sample area) using the Nd:YAG laser at a setting of 1.5 W, 15 pps with a 200 μm glass fiber from an angle of about 5°. The bacteria were then removed from the dentin using vibration and plated out on culture dishes that were selective forStreptococcus mutans. When compared with untreated control slices, counting of the colonies revealed a highly significant elimination of bacteria for all thicknesses following laser irradiation. Although the intensity of the laser irradiation decreased after penetration of a 1000-μm dentin slice, the bactericidal mode of action was still e

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.29

年代:1997

数据来源: MAL

摘要:

ABSTRACTThis study examines the application of a diode laser with a wavelength of 805 nm for periodontal treatment. While the use of the diode laser in this field has not been investigated so far, several authors have reported on the use of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser for such applications. The aim of this study was to examine the immediate effect of the diode laser in reducing the bacterial concentration in periodontal pockets. Important periodontal indices (PBI, CPITN) were assessed in 50 patients to obtain initial values for a planned long-term study and to select appropriate periodontal pockets for this study. The periodontal pockets were required to have a minimum depth of 4 mm. Only proximal pockets were included in this study. The patients were subdivided into two groups. After microbiological samples had been collected with sterile paper tips, the group selected for laser treatment was subjected to scaling. One week after scaling, the patients underwent laser treatment. One week later, a second series of microbiological samples were obtained and the patients were subjected again to scaling; this time, however, they did not undergo laser treatment after 1 week. Two weeks after scaling, another series of microbiological samples was collected. The microbiological samples were evaluated to verify bacterial elimination from the periodontal pockets. A comparison between the initial and the final bacterial counts revealed that irradiation with the diode laser facilitates considerable bacterial elimination, especially ofActinobacillus actinomycetemcomitans, from periodontal pockets.

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.33

年代:1997

数据来源: MAL

摘要:

ABSTRACTIn this article, the results of a 5-year investigation of low-energy laser therapy for the treatment of some oncological and infection diseases are presented. We used special infrared (IR) lasers with a wavelength of 890 nm in our investigations. All laser actions on organisms occurred through the skin only (a noninvasive method).

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.39

年代:1997

数据来源: MAL

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.45

年代:1997

数据来源: MAL

ISSN:1044-5471    

DOI:10.1089/clm.1997.15.47

年代:1997

数据来源: MAL