脉冲Nd∶YAG激光联合羟基磷灰石对根尖切除的作用
作者：
单位：
关键词：激光；根尖切除术；羟基磷灰石
中国激光医学杂志990313Y. BEN HATIT, P. GOUDOT, O. DILANCHIAN, C. SEVERIN, K. SOHR ABI
摘要
目的 评价脉冲Nd∶YAG激光对应用羟基磷灰石的根尖切除术后的牙齿根部的作用。
方法 70颗拔出的上颌中切齿，牙髓腔扩张后用马来乳胶封闭并覆以氧化锌。 随机分为7组，每组10颗，第1组为对照组；第2、3、4组为单纯激光照射组，以脉冲Nd∶YAG 激光照射，脉宽150 μs，最高频率30Hz，波长1064nm，照射时间20s，功率分别为0.5、1.0、1.5W；第5、6、7组为羟基磷灰石加激光照射组，去除马来乳胶0.5mm，换以羟基磷灰石，激光照射方法同2、3、4组。7组牙齿标本均进行扫描电镜下观察。
, http://www.100md.com
结果 电镜观察可见单纯激光照射组牙本质表面出现很多孔状熔化及结晶；羟基磷灰石处理组，激光照射后羟基磷灰石未见明显改变，而在其周围的牙本质表面出现熔化及结晶，在二者之间有明显界限，说明二者没有相互融合。
结论 脉冲Nd∶YAG激光对羟基磷灰石物质无明显作用，牙本质与羟基磷灰石之间也没有反应；在实验所用激光剂量范围内，激光照射可造成牙本质熔化及结晶 。(刘爱琴 译)
Effect of Pulsed Nd∶YAG Laser on the Apical Root Dentin when
Associated with Hydroxyapatite
Y. BEN HATIT, P. GOUDOT, O. DILANCHIAN, C. SEVERIN, K. SOHR ABI
, 百拇医药
1.European Laser Academy, Luxembourg 2.Reims University, France
ABSTRACT
Objective The purpose of this study was to evaluate the effects of the pulsed Nd∶ YAG laser on the apical root dentin of extracted human teeth, following apicoectomy when associated with hydroxyapatite.
Methods Seventy sound, extracted maxillary central incisors were used in this study. The canals were enlarged and then obturated with laterally condensed gutta-percha and zinc oxide sealer. The seventy teeth were divided in seven groups of ten teeth each: one group was used as control group, three other groups were treated by the Nd∶YAG laser only and the three remaining groups(teeth with the hydroxyapatite material) were treated in the name way. All seven groups were observed under the scanning electron microscope.
, 百拇医药
Results The SEM study showed melted dentin on the apical surface but noevidence of hydr oxyapatite fusion to the dentin.
Conclusions Some craters were observed at the surface of the dentin, investigation showed that this was most likely due to the preparation method for SEM observation.
Key word Lasers； Apicoectomy； Hydroxyapatite
In the last ten years, lasers have been introduced into the dental medicine field. Some high powered laser beams, such as CO2 laser, have been used for the cuttingand vaporization of tissue to replace the classic scalpel[1-5]. CO2 and other lasers have been used successfully in dental surgery[6-7]. The Argon laser, 488nm, showed an important interest for the polymerization of the composites and is successfully used for this purpose[8-10]. Another type of laser is the Nd∶YAC laser (1064nm), which was intr oduced into dental practice in 1989 and has been recommended for a number of applications in hard and soft tissues[11-13]. In the last five years, manu facturers have developed a thin optic fiber of 200μm. This led to a recommendation that the Nd∶YAG laser be used for endodontic treatment to sterilize the canal and also to vitrify the inner dentinal walls of the canal. Studies in this field were few and quite contradictory. It is obvious that the rise of the temper ature can contribute to the sterilization of the canal and may produce some dent in structure alteration as well as cause possible periodontal ligament damage [14-17].
, 百拇医药
This study was designed to evaluate the pulsed Nd∶YAG laser effects on the hydroxyapatite when added to the dentin at the apex of a tooth prepared for an apicoectomy. For this and other treatments, there is a great deal of interest in pulsed lasers as a means of controlling or reducing the amount of heat generated during lasing.
MATERIALS AND METHODS
Seventy sound, extracted maxillary central incisors were used in this study. The teeth had been preserved in normal saline after extraction until the teeth were used inthis experiment. Preoperative radiographs showed an absence of multiple canals, calcifications, apical curvatures or fractures.
, 百拇医药
The crowns were removed with a high speed fissure bur at the cemento-enamel jun ction before root canal instrumentation to eliminate any variables in access preparation. The remaining pulp was removed with a barbed broach and the length of the root canals was determined by passing a ＃20 K-type file into the canal until the tip was just visible at the apical foramen and then subtracting 1mm from this length.
The canals were enlarged with K-type files using a serial (step-back) technique with recapitulation of files to establish a progressive tapering root canal preparation. In this instrumentation process, the apical portion of each canal was enlarged to ＃45 or ＃50 file. Any tooth requiring a size larger than ＃50 file for adequate cleaning was discarded and replaced with another tooth.
, 百拇医药
The apical third of each canal was flared using hand files in a step back techni que and the coronal two thirds of the canals were flared to a gradual taper using ＃2 and ＃3 Gates Glidden burs. After each instrumentation, the canals were irrigated copiously with normal saline solution.
After drying the canals with paper points, all root canal were obturated with la terally condensed gutta-percha and zinc oxide eugenol sealer.
The apical 2mm of each root was resected with a 45° angle to the long axis of the root in a labio-lingual direction by a ＃701 high speed bur and water coolant.
, 百拇医药
The roots were then randomly divided into 7 groups of 10.
In group 1, control group (C.G.), no additional procedures except obturation of the canals and apical resection were done.
In groups 2, 3 and 4 (or Al, A2 and A3), all the resected surfaces of the roots were irradiated by the 1064nm pulsed Nd∶YAG laser for 20 seconds with 0.5, 1.0 and 1.5 watts of power, respectively.
, http://www.100md.com
In groups 5, 6 and 7 (or B1, B2 and B3), after removal of 0.5mm of gutta -percha by a hot instrument, hydroxyapitate (Interpore 200) was placed in the created space. Subsequently, all of the cut surfaces, as in groups Al, A2 and A3, were irradiated by the same laser at 0.5, 1.0 and 1.5 watts of power, respectively.
A pulsed Nd∶YAG laser with a wavelength of 1 064 nm, pulse duration of 150μs (manufactured by ELEN, Florence, Italy), maximum output power of 3.0 watts and a total energy of 100 mJ per pulsation and with a maximum freq uency of 30Hz was used. All laser experiments were performed in the laboratory by using a 300 m optic fiber. The procedures were accomplished by non contact, defocused irradiation of the dentin and the hydroxyapatite. After irradiation all samples were immersed in a formalin solution for two hours, then rinsed and dried by using an alcohol solution, atter dehydration, the samples were sent to the laboratory to be prepared for SEM examination.
, 百拇医药
RESULTS
Overall, differences were found between the experimental groups. SEM analysis of the A group (A1, A2, A3) treated only with the Nd∶YAG Laser revealed an important alteration on the apical lased dentin surface. Regardless of the laser power used, there was always a dentin surface alteration indicating that dentin is melted when lased by the Nd∶YAG laser. Under high magnification, the lased dentinal surface shows a porous pattern with a melted and crystallized appearance.
, http://www.100md.com
SEM examination of B group (B1, B2, B3) treated with hydroxyapatite and then lased by Nd∶YAG laser with different power revealed no apparent changes on the lased hydroxyapatite placed on the apex. However, the lased apical dentinal surface just around thehydroxyapatite revealed an important and apparent alter a-
tion on the dentinal surface. Melted and crystallized surface is seen.
The examination of the same group showed a gap between the hydroxyapatite placed on the apex and the lased melted dentin, indicating that no fusion was happened between the hydroxyapatite and the lased dentin as expected.
, 百拇医药
DISCUSSION
Analysis of the specimens treated with the Nd∶YAG laser at different power levels, when compared to the control group, showed an important alteration of the dentin surface, melted areas of dentin were seen. This dentin surface change was the result of the effect of the high energy delivered by the Nd∶YAG laser. At the same time, the SEM study showed that there was no effect of the Nd∶YAG laser on the hydroxyapatite powder placed on the apical surface. Expected melting of the dentin to the hydroxyapatite was not evident. A gap between the hydroxyapatite and the dentinal edge is evident, showing the lack of adaptation of the hydroxyapatite to the dentin. Cracks and small cratering were seen in some area of the apical surface in all groups, which is due to the preparation method for SEM analysis. Further studies, are needed to determine the degree of the hardness of the melted dentin surface. Also, studies are needed to measure the depth of the melted dentin as well as the effect of this treatment on the apical seal, if any.
, 百拇医药
CONCLUSION
The SEM study showed no effect of the Nd∶YAG laser on thehydroxyapatite materia l and no interaction with the dentin and the hydroxyapatite. At the present expe rimental energy levels, a melted and vitrified dentin alteration was achieved.
For correspondence:Y. BEN HATIT, P. GOUDOT, O. DILANCHIAN, K. SOHR ABI European Laser Academy, Prof. Dr. Y.
C. SEVERIN,BEN HATIT Bd. L. METTEWIE, 47 1080 Brussels, Belgium
, 百拇医药
REFERENCES
1 Ben Hatit Y, et al. Removal of oral hyperplasia using C02 laser. Laser, Official, J Eur Med Laser Assoc, 1990, 1-2:14-18.
2 Abt E, Wigdor H, Lobraico R, et al. Removal of benign in traoral masses using the CO2 laser. J Am Dent Assoc, 1987, 115:729-731.
3 Pecaro BC, Garehime WJ. CO2 laser in oral and maxillof acial surgery. J Oral Maxillofacial Surg, 1983, 41:725-728.
, 百拇医药
4 Sachs SA, Borden GE. The utilization of the CO2 laser in the treatment of recurrent papillomatosis: report of Case. J Oral Surg, 1981, 39:299.
5 Horch H, Gerlach K, Schaefer H. CO2 laser surgery of oral premalignant lesions. Int J Oral Maxillofacial Surg, 1986, 15:19-24.
6 Okshiro T, et al. Treatment of pigmentation of the lips and oral mucosa in Peutz-Jegher's syndrome using ruby lasers. Br J Plast Surg, 1980, 33:346-349.
, 百拇医药
7 Roberto P, et al. Laser dentistry: a new application of the excimer laser in root canal therapy. Lasers Surg Med, 1989, 9:352-357.
8 Kelsey WP, et al. Enhancement of physical properties of resin restorative materials by laser polmerization. Lasers Surg Med, 1989, 9:62 3-627.
9 Thomas V, et al. Laser photopolymerization of dental materials with potential endodontic applications. J Endodontics, 1990, 16:265-28 6.
, 百拇医药
10 Ben Hatit Y. The effects of a pulsed Nd∶YAG laser on subgingival bacterial flora and on cementum: An in vivo study. J Clin Laser Med Surg, 199 6, 14:3. 137-143.
11 Ben Hatit Y. The Nd∶YAG laser in dentistry Laser, Official J Eur Med Laser Assoc, 1990, 1-2:17-21.
12 Ben Hatit Y. Les laser: indications et limites enme'decine dentaire. J Dentaire du Que'bec, 1992, 29:167-170.
13 Adrian JC. Pulp effects of the Nd∶YAG laser. A preliminary report. Oral Surg, 1977, August: 301-305.
, 百拇医药
14 Tulip J, et al. Scanning electron microscope analysis of canal wall dentin following Nd∶YAG laser irradiation. J Endodontics, 1984, 10:428-43 1.
15 Hardee MW, et al. Evaluation of the antibacterial effects of in tracanal Nd∶YAG laser irradiation. J Endodontics, 1994, 8:377-380.
16 Launay Y, et al. Thermal effects on dental tissues. Lasers Surg Med, 1987, 7:473-477.
17 Ben Hatit Y. Introduction to lasers in biomedicine. Eur Dent, 1 994, 3:28-29.
(收稿日期：1999-07-05), 百拇医药
单位：
关键词：激光；根尖切除术；羟基磷灰石
中国激光医学杂志990313Y. BEN HATIT, P. GOUDOT, O. DILANCHIAN, C. SEVERIN, K. SOHR ABI
摘要
目的 评价脉冲Nd∶YAG激光对应用羟基磷灰石的根尖切除术后的牙齿根部的作用。
方法 70颗拔出的上颌中切齿，牙髓腔扩张后用马来乳胶封闭并覆以氧化锌。 随机分为7组，每组10颗，第1组为对照组；第2、3、4组为单纯激光照射组，以脉冲Nd∶YAG 激光照射，脉宽150 μs，最高频率30Hz，波长1064nm，照射时间20s，功率分别为0.5、1.0、1.5W；第5、6、7组为羟基磷灰石加激光照射组，去除马来乳胶0.5mm，换以羟基磷灰石，激光照射方法同2、3、4组。7组牙齿标本均进行扫描电镜下观察。
, http://www.100md.com
结果 电镜观察可见单纯激光照射组牙本质表面出现很多孔状熔化及结晶；羟基磷灰石处理组，激光照射后羟基磷灰石未见明显改变，而在其周围的牙本质表面出现熔化及结晶，在二者之间有明显界限，说明二者没有相互融合。
结论 脉冲Nd∶YAG激光对羟基磷灰石物质无明显作用，牙本质与羟基磷灰石之间也没有反应；在实验所用激光剂量范围内，激光照射可造成牙本质熔化及结晶 。(刘爱琴 译)
Effect of Pulsed Nd∶YAG Laser on the Apical Root Dentin when
Associated with Hydroxyapatite
Y. BEN HATIT, P. GOUDOT, O. DILANCHIAN, C. SEVERIN, K. SOHR ABI
, 百拇医药
1.European Laser Academy, Luxembourg 2.Reims University, France
ABSTRACT
Objective The purpose of this study was to evaluate the effects of the pulsed Nd∶ YAG laser on the apical root dentin of extracted human teeth, following apicoectomy when associated with hydroxyapatite.
Methods Seventy sound, extracted maxillary central incisors were used in this study. The canals were enlarged and then obturated with laterally condensed gutta-percha and zinc oxide sealer. The seventy teeth were divided in seven groups of ten teeth each: one group was used as control group, three other groups were treated by the Nd∶YAG laser only and the three remaining groups(teeth with the hydroxyapatite material) were treated in the name way. All seven groups were observed under the scanning electron microscope.
, 百拇医药
Results The SEM study showed melted dentin on the apical surface but noevidence of hydr oxyapatite fusion to the dentin.
Conclusions Some craters were observed at the surface of the dentin, investigation showed that this was most likely due to the preparation method for SEM observation.
Key word Lasers； Apicoectomy； Hydroxyapatite
In the last ten years, lasers have been introduced into the dental medicine field. Some high powered laser beams, such as CO2 laser, have been used for the cuttingand vaporization of tissue to replace the classic scalpel[1-5]. CO2 and other lasers have been used successfully in dental surgery[6-7]. The Argon laser, 488nm, showed an important interest for the polymerization of the composites and is successfully used for this purpose[8-10]. Another type of laser is the Nd∶YAC laser (1064nm), which was intr oduced into dental practice in 1989 and has been recommended for a number of applications in hard and soft tissues[11-13]. In the last five years, manu facturers have developed a thin optic fiber of 200μm. This led to a recommendation that the Nd∶YAG laser be used for endodontic treatment to sterilize the canal and also to vitrify the inner dentinal walls of the canal. Studies in this field were few and quite contradictory. It is obvious that the rise of the temper ature can contribute to the sterilization of the canal and may produce some dent in structure alteration as well as cause possible periodontal ligament damage [14-17].
, 百拇医药
This study was designed to evaluate the pulsed Nd∶YAG laser effects on the hydroxyapatite when added to the dentin at the apex of a tooth prepared for an apicoectomy. For this and other treatments, there is a great deal of interest in pulsed lasers as a means of controlling or reducing the amount of heat generated during lasing.
MATERIALS AND METHODS
Seventy sound, extracted maxillary central incisors were used in this study. The teeth had been preserved in normal saline after extraction until the teeth were used inthis experiment. Preoperative radiographs showed an absence of multiple canals, calcifications, apical curvatures or fractures.
, 百拇医药
The crowns were removed with a high speed fissure bur at the cemento-enamel jun ction before root canal instrumentation to eliminate any variables in access preparation. The remaining pulp was removed with a barbed broach and the length of the root canals was determined by passing a ＃20 K-type file into the canal until the tip was just visible at the apical foramen and then subtracting 1mm from this length.
The canals were enlarged with K-type files using a serial (step-back) technique with recapitulation of files to establish a progressive tapering root canal preparation. In this instrumentation process, the apical portion of each canal was enlarged to ＃45 or ＃50 file. Any tooth requiring a size larger than ＃50 file for adequate cleaning was discarded and replaced with another tooth.
, 百拇医药
The apical third of each canal was flared using hand files in a step back techni que and the coronal two thirds of the canals were flared to a gradual taper using ＃2 and ＃3 Gates Glidden burs. After each instrumentation, the canals were irrigated copiously with normal saline solution.
After drying the canals with paper points, all root canal were obturated with la terally condensed gutta-percha and zinc oxide eugenol sealer.
The apical 2mm of each root was resected with a 45° angle to the long axis of the root in a labio-lingual direction by a ＃701 high speed bur and water coolant.
, 百拇医药
The roots were then randomly divided into 7 groups of 10.
In group 1, control group (C.G.), no additional procedures except obturation of the canals and apical resection were done.
In groups 2, 3 and 4 (or Al, A2 and A3), all the resected surfaces of the roots were irradiated by the 1064nm pulsed Nd∶YAG laser for 20 seconds with 0.5, 1.0 and 1.5 watts of power, respectively.
, http://www.100md.com
In groups 5, 6 and 7 (or B1, B2 and B3), after removal of 0.5mm of gutta -percha by a hot instrument, hydroxyapitate (Interpore 200) was placed in the created space. Subsequently, all of the cut surfaces, as in groups Al, A2 and A3, were irradiated by the same laser at 0.5, 1.0 and 1.5 watts of power, respectively.
A pulsed Nd∶YAG laser with a wavelength of 1 064 nm, pulse duration of 150μs (manufactured by ELEN, Florence, Italy), maximum output power of 3.0 watts and a total energy of 100 mJ per pulsation and with a maximum freq uency of 30Hz was used. All laser experiments were performed in the laboratory by using a 300 m optic fiber. The procedures were accomplished by non contact, defocused irradiation of the dentin and the hydroxyapatite. After irradiation all samples were immersed in a formalin solution for two hours, then rinsed and dried by using an alcohol solution, atter dehydration, the samples were sent to the laboratory to be prepared for SEM examination.
, 百拇医药
RESULTS
Overall, differences were found between the experimental groups. SEM analysis of the A group (A1, A2, A3) treated only with the Nd∶YAG Laser revealed an important alteration on the apical lased dentin surface. Regardless of the laser power used, there was always a dentin surface alteration indicating that dentin is melted when lased by the Nd∶YAG laser. Under high magnification, the lased dentinal surface shows a porous pattern with a melted and crystallized appearance.
, http://www.100md.com
SEM examination of B group (B1, B2, B3) treated with hydroxyapatite and then lased by Nd∶YAG laser with different power revealed no apparent changes on the lased hydroxyapatite placed on the apex. However, the lased apical dentinal surface just around thehydroxyapatite revealed an important and apparent alter a-
tion on the dentinal surface. Melted and crystallized surface is seen.
The examination of the same group showed a gap between the hydroxyapatite placed on the apex and the lased melted dentin, indicating that no fusion was happened between the hydroxyapatite and the lased dentin as expected.
, 百拇医药
DISCUSSION
Analysis of the specimens treated with the Nd∶YAG laser at different power levels, when compared to the control group, showed an important alteration of the dentin surface, melted areas of dentin were seen. This dentin surface change was the result of the effect of the high energy delivered by the Nd∶YAG laser. At the same time, the SEM study showed that there was no effect of the Nd∶YAG laser on the hydroxyapatite powder placed on the apical surface. Expected melting of the dentin to the hydroxyapatite was not evident. A gap between the hydroxyapatite and the dentinal edge is evident, showing the lack of adaptation of the hydroxyapatite to the dentin. Cracks and small cratering were seen in some area of the apical surface in all groups, which is due to the preparation method for SEM analysis. Further studies, are needed to determine the degree of the hardness of the melted dentin surface. Also, studies are needed to measure the depth of the melted dentin as well as the effect of this treatment on the apical seal, if any.
, 百拇医药
CONCLUSION
The SEM study showed no effect of the Nd∶YAG laser on thehydroxyapatite materia l and no interaction with the dentin and the hydroxyapatite. At the present expe rimental energy levels, a melted and vitrified dentin alteration was achieved.
For correspondence:Y. BEN HATIT, P. GOUDOT, O. DILANCHIAN, K. SOHR ABI European Laser Academy, Prof. Dr. Y.
C. SEVERIN,BEN HATIT Bd. L. METTEWIE, 47 1080 Brussels, Belgium
, 百拇医药
REFERENCES
1 Ben Hatit Y, et al. Removal of oral hyperplasia using C02 laser. Laser, Official, J Eur Med Laser Assoc, 1990, 1-2:14-18.
2 Abt E, Wigdor H, Lobraico R, et al. Removal of benign in traoral masses using the CO2 laser. J Am Dent Assoc, 1987, 115:729-731.
3 Pecaro BC, Garehime WJ. CO2 laser in oral and maxillof acial surgery. J Oral Maxillofacial Surg, 1983, 41:725-728.
, 百拇医药
4 Sachs SA, Borden GE. The utilization of the CO2 laser in the treatment of recurrent papillomatosis: report of Case. J Oral Surg, 1981, 39:299.
5 Horch H, Gerlach K, Schaefer H. CO2 laser surgery of oral premalignant lesions. Int J Oral Maxillofacial Surg, 1986, 15:19-24.
6 Okshiro T, et al. Treatment of pigmentation of the lips and oral mucosa in Peutz-Jegher's syndrome using ruby lasers. Br J Plast Surg, 1980, 33:346-349.
, 百拇医药
7 Roberto P, et al. Laser dentistry: a new application of the excimer laser in root canal therapy. Lasers Surg Med, 1989, 9:352-357.
8 Kelsey WP, et al. Enhancement of physical properties of resin restorative materials by laser polmerization. Lasers Surg Med, 1989, 9:62 3-627.
9 Thomas V, et al. Laser photopolymerization of dental materials with potential endodontic applications. J Endodontics, 1990, 16:265-28 6.
, 百拇医药
10 Ben Hatit Y. The effects of a pulsed Nd∶YAG laser on subgingival bacterial flora and on cementum: An in vivo study. J Clin Laser Med Surg, 199 6, 14:3. 137-143.
11 Ben Hatit Y. The Nd∶YAG laser in dentistry Laser, Official J Eur Med Laser Assoc, 1990, 1-2:17-21.
12 Ben Hatit Y. Les laser: indications et limites enme'decine dentaire. J Dentaire du Que'bec, 1992, 29:167-170.
13 Adrian JC. Pulp effects of the Nd∶YAG laser. A preliminary report. Oral Surg, 1977, August: 301-305.
, 百拇医药
14 Tulip J, et al. Scanning electron microscope analysis of canal wall dentin following Nd∶YAG laser irradiation. J Endodontics, 1984, 10:428-43 1.
15 Hardee MW, et al. Evaluation of the antibacterial effects of in tracanal Nd∶YAG laser irradiation. J Endodontics, 1994, 8:377-380.
16 Launay Y, et al. Thermal effects on dental tissues. Lasers Surg Med, 1987, 7:473-477.
17 Ben Hatit Y. Introduction to lasers in biomedicine. Eur Dent, 1 994, 3:28-29.
(收稿日期：1999-07-05), 百拇医药