• Title/Summary/Keyword: Pulsed Nd:YAG laser

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Wound Healing After Gingivectomy Using Pulsed Nd : YAG Laser In The Rat (백서에서 Pulsed Nd : YAG Laser에 의한 치은절제술후의 치유양상)

  • Kim, Ok-Su;Chung, Hyun-Ju
    • Journal of Periodontal and Implant Science
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    • v.26 no.1
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    • pp.293-308
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    • 1996
  • Recently, dental laser have been applied for removal of soft tissues, hemostasis and blood coagulation, removal of benign and malignant tumor, treatment of leukoplakia, aphthous ulcer and herpetic lesion, implant second surgery, removal of granulation tissue, frenectomy, clinical crown lengthening, gingivectomy, gingivoplasty, and treatment of dentin hypersensitivity. Even though the frequency of laser treatment is increasing, the research on the healing process after gingivectomy using pulsed Nd : YAG laser is very rare. The purpose of this study was to observe and compare the wound healing after gingivectomy using scalpel and pulsed Nd : YAG laser in the rat. Gingivectomy was performed using pulsed Nd : YAG laser(SUNRISE Technologies, U.S.A., 1.5 Watts, 10 pps) on the buccal gingiva of right maxillary first molar and using scalpel(No.12) on the contralateral side. Those sites treated by surgical scalpel were designated as the control, and by pulsed Nd : YAG laser as the experimental group. Animals were sacrificed at 1, 2, 3, 5, 7, 11 and 14 days postoperatively, and specimens were histologically observed under light microscope. The results were as follows : 1. Clinical observation Normal color and shape were observed at the 5th day ill the control group and the 7th day in the experimental group. 2. Histologic findings 1) In the control group, denser inflammatory infiltration was observed. 2) Epithelialization started at the 2nd day in the control group, similar to the experimental group, and completed at the 11th to the 14th day postoperatively. 3) In the experimental group, connective tissue showed the vacuole formation and degenerative change during early healing period. Healing of connective tissue was slower in the experimental group than in the control group by 2 days. 4) In the both groups, wound healing was completed at the 2nd week. From this study, gingivectomy using pulsed Nd : YAG laser seems to result in a little delayed wound healing process, compared to the gingivectomy using scalpel. Considering the clinical advantages of laser surgery, pulsed Nd : YAG laser might be useful device for gingivectomy.

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A Study on the Antibacterial Effects of Pulsed Nd: YAG Laser Irradiation to Streptococcus Mutans (Pulsed Nd : YAG Laser 조사의 Streptococcus mutans에 대한 효과)

  • Woo-Cheon Kee
    • Journal of Oral Medicine and Pain
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    • v.22 no.1
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    • pp.15-22
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    • 1997
  • In order to investigate the antibacterial effects of pulsed Nd:YAG Laser concerning to Streptococcus mutans, Streptococcus mutans was cultured and standardized and plated in 96 well plates. After that, black dye and chlorhexidine were applied and pulsed Nd:YAG Laser was irradiated to plates. Experimental groups which was applied with black dye and chlorhexidine were divided into 5 groups by concentration. And experimental groups and control group were subdivided as unlased and lased of 20, 40, and 60J. After laser irradiation, All groups were plated in agar plates and incubated for 18 hours. Bacterial colonies were counted and analysed comparitively, and the temperature of culture medium was measured on every laser irradiation. The results were obtained as follows; 1. In case of laser irradiation only, there is no significant reduction in number of Streptococcus mutans by irradiated energy of laser. 2. In case of black dye application, there is no difference by concentration of black dye but there is decrease when applied Laser and black dye simultaneously. 3. When applied chlorhexidine, the number of Streptococcus mutans was decreased according to increase of concentration, but there is no difference by irradiated energy of laser. 4. The temperature of culture medium was increased according to increase of irradiated energy of Laser, and the number of Streptococcus mutans was reduced remarkably just above 50 centigrade and killed above 70 centigrade. As above results, pulsed Nd:YAG Laser has well-absorbing affinity to black dye. And antibacterial effect of pulsed Nd:YAG Laser against Streptococcus mutans is seemed to be due to increase of temperature.

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EFFECT OF ND : YAG LASING ON TEMPERATURE RISING AND PROPERTIES OF MATTER OF DENTAL IMPLANTS (Nd : YAG LASER 조사가 치과 임플란트의 물성과 온도 상승에 미치는 영향)

  • Lee, Ho-Yong
    • The Journal of Korean Academy of Prosthodontics
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    • v.34 no.3
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    • pp.489-500
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    • 1996
  • Pulsed Nd : YAG LASER has been applied to various fields in clinical dentistry including the treatment of peri-implantitis. However, LASER can affect properties of matter of dental implants which are important to maintaining the health of peri-implant tissue and can raise its temperature during lasing. So there have been warings of using LASER to treat peri-implantitis. But, the effects of laser on dental implants itself are not certain yet. So we measured the temperature rising, examined matter of properties by SEM and EDX before and after pulsed Nd : YAG lasing various intensity. 7 TPS implants and 7 HPS implants were used and pulsed Nd : YAG LASER was used in 0.3W, 1.0W, and 2.0W. 1. 2.0W LASER made polished neck portion of HPS implants reach $39.2^{\circ}C$ after 5 seconds lasing. 2. LASER made crater-like defects on plasma sprayed surface and surfaces were melted and divided by fragments after lasing. 3. There was no specific evidence of element change after lasing.

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The output characteristics of pulsed Nd:YAG laser with voltage variable capacitor-charging system (충전전압 가변방식을 이용한 펄스형 Nd:YAG 레이저의 출력특성에 관한 연구)

  • Moon, D.S.;Hong, J.H.;Song, K.Y.;Song, W.J.;Kim, K.H.;Kim, H.J.
    • Proceedings of the KIEE Conference
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    • pp.1703-1705
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    • 2001
  • The pulsed Nd:YAG laser is used widely for materials processing and medical instrument etc. It is important to control the laser energy in those fields using a pulsed Nd:YAG laser. In this paper, constant-frequency current resonant half-bridge inverter and Cockcroft-Walton circuit are used to charge the energy storage capacitor variably. This laser power supply is designed and fabricated which has no high-voltage transformer, less switching losses, compact size and capability in varying the laser output power. Also, the output characteristics of this Nd:YAG laser system are investigated. The tested results are described.

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A Study on the Anesthetic Effects of Pulsed Nd:YAG Laser Irradiation to the Oral Mucosa and the Teeth (Nd:YAG 레이저 조사에 의한 치아 및 구강점막의 마취효과)

  • 최재갑
    • Journal of Oral Medicine and Pain
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    • v.23 no.1
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    • pp.1-9
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    • 1998
  • The aim of the study was to evaluate the anesthetic Effecs of pulsed Nd:YAG laser irradiation to the oral mucosa and the teeth. Twenty subjects who didn't have a history of significant systemic or current oral disease were included in this study. All the subjects were divided randomly into the experimental group and the control group with 10 for each group. Pain thresholds were measured with Weighted Needle Pinprick Sensory Threshold Test for the mucosal surface of lower lip and with electric pulp test for the upper right central incisor respectively, before and immediately after pulsed Nd:YAG laser irradiation in the condition of 2 watt, 20pps for 2 minute at 10mm distance. The experiment was double-blinded clinical trial. The results were as follows : 1. The mean pain threshold of the mucosal surface of lower lip for Weighted Needle Pinprick Sensory Threshold Test was 2.94(1.00g for the contral group respectively, and there was no statistical difference between two groups. 2. The mean pain threshold of the mucosal surface of lower lip was significantly increased immediately after pulsed Nd:YAG laser irradiation. 3. The mean pain threshold of the upper right central incisor for eledtric pulp test was 34.50(4.97V in the experimental group and 34.00(13.08V in the control group respectively, and there was no statistical difference between two groups. 4. The mean pain threshold of the upper right central incisor was significantly increased immediately after pulsed Nd:YAG laser irradiation.

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Investigation of Zircaloy-4 weldability using a pulsed Nd:YAG laser (펄스형 Nd:YAG 레이저를 이용한 지르칼로이-4 용접특성 조사)

  • 김수성;김덕현;김철중;이종민
    • Journal of Welding and Joining
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    • v.9 no.1
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    • pp.23-31
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    • 1991
  • Laser beam weldability of zircaloy-4was investigated using a pulsed Nd: YAG laser of 200W average power. Mechanical properties of laser and GTA bead-on-plate welded zircaloy-4 test specimens were compared. The influence of plasma generated during laser welding was analyzed and optimum laser welding parameters were investigated.

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Development of high repetition rate and high power pulsed Nd:YAG laser power supply using ZCS resonant converter (ZCS공진형 컨버터를 적용한 고반복 대출력 펄스형 Nd:YAG 레이저 전원장치 개발)

  • Joe, K.Y.;Kim, E.S.;Byun, Y.B.;Kim, H.J.;Park, J.M.;Lee, H.W.
    • Proceedings of the KIEE Conference
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    • pp.514-517
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    • 1996
  • Zero current switching(ZCS) series resonant converter is used to control laser power density in a pulsed Nd:YAG laser power supply. The high power and high repetition rate paused Nd:YAG laser is designed and fabricated to control current pulse width and pulse repetition rate in the double elliptical laser oscillator. In order to find out operational characteristics of pulsed Nd:YAG laser, the electrical properties of driving power supply and laser output power are investigated and experimented by changing of the current pulse width from 200uS to 350uS(step 50uS) and pulse repetition rate range of 500pps(pulse per second) to 1150pps. From that result, we obtaind maximum efficiency of 1.83% and maximum laser output or 220W at the condition of 350 uS and 1150pps with one Nd:YAG rod), and obtained that of more than 400W with two laser head connecting series.

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Development of a pulsed Nd:YAG laser materials processing system (정밀 용접용 펄스형 Nd:YAG 레이저 가공기 개발)

  • 김덕현;정진만;김철중;이종민
    • Journal of Welding and Joining
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    • v.9 no.1
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    • pp.32-39
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    • 1991
  • A 200W pulsed Nd: YAG laser for fine welding was developed. The important laser parameters such as laser peak power, average power, pulse width, and pulse energy for welding were studied. In order to obtain the sufficient laser power density for welding, thermal lensing effects were analyzed and a laser resonator with laser beam divergence was designed. The power supply unit was designed to support up to 7kW input. The pulse control unit was developed using a GTO thyristor and could control over 100kW input power to obtain 3.5kW peak power laser. Also due to the GTO thyristor the pulse width could be varied continuously from 0.1 to 20 msec and maximum repetition rate was as high as 300pps.

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