牙周组织病

20062333盐酸米诺环素软膏牙周袋内药物释放特征的体内研究；20062334脉冲Nd：YAG激光照射对人牙周膜成纤维细胞的影响；20062335米诺环素对牙周膜细胞在根面上附着和增殖的影响；20062336牙周炎与类风湿关节炎的相关性研究；20062337十二烷基硫酸钠对人牙周膜细胞活性影响的实验研究；20062338NGFmRNA在人牙周膜成纤维细胞的表达。[编者按]     

Er:YAG激光对人牙周膜细胞增殖和迁移的影响

目的比较不同输出功率和照射时间的Er:YAG激光照射对体外培养的人牙周膜细胞增殖、克隆形成、迁移及转化生长因子-β1(TGF-β1)分泌的影响。方法酶消化法培养人牙周膜细胞,传至3~6代用于实验,按不同的输出功率、相同照射时间(0、0.45、0.60、0.75 W,10 s)及不同照射时间、相同输出功率(0、10、30、60 s,0.60 W)对接种细胞行Er:YAG激光照射,通过噻唑蓝法、克隆形成、划痕实验、酶联免疫吸附法观察激光照射对人牙周膜细胞增殖、克隆形成能力、细胞迁移及TGF-β1分泌的影响。结果输出功率为0.45、0.60 W,照射时间10 s时,可促进细胞的增殖及克隆形成(P<0.05),迁移速度和TGF-β1分泌也较对照组快,但此两组间差异无统计学意义。照射时间10 s,输出功率0.60 W时,细胞增殖及克隆形成率明显高于对照组(P<0.05),迁移速度和TGF-β1分泌较对照组快;60 s反之。结论在适度的功率和照射时间,Er:YAG激光对人牙周膜细胞增殖、克隆形成、迁移及TGF-β1分泌具有促进作用。     

Nd:YAG激光辅助去除陶瓷托槽对托槽的粘接强度及髓腔温度影响的研究

目的　研究国产DL-200型计算机控制脉冲Nd:YAG口腔激光机去除陶瓷托槽的最佳技术参数。方法　观察未使用激光照射组,以及激光功率5 W、照射时间2 s组,功率3 W、照射时间3 s组和功率2 W、照射时间5 s 组,3种参数下激光对陶瓷托槽的粘接强度及髓腔温度的影响。结果　①激光照射后可以显著降低陶瓷托槽的粘接强度,约降低50%,4组间的平均粘接强度差异有统计学意义(P<0·001);②激光照射后各组髓腔温度均升高,各组温度升高有统计学意义(P<0·001),激光功率3 W、照射时间3 s组髓腔温度只升高3·65℃,较其他两组低。结论　国产DL-200型计算机控制脉冲Nd:YAG口腔科激光治疗机激光照射后可以显著降低陶瓷托槽的粘接强度,去除陶瓷托槽的最佳参数是激光功率3 W、照射时间3 s,这一能量不会明显升高牙髓温度。     

Er：YAG 激光照射对人牙周膜成纤维细胞增殖的影响

目的：观察离体培养的人牙周膜成纤维细胞在 Er：YAG 激光照射后其增殖能力的变化。方法：离体培养的人牙周膜成纤维细胞,进行常规免疫组化染色,鉴定细胞来源。选用第5代人牙周膜成纤维细胞,随机分为5组,A 组为对照组,不接受激光照射。实验组分别接受频率为10 Hz 的不同能量 Er：YAG 激光照射,参数分别为 B 组：50 mJ,C 组：100 mJ,D 组：150 mJ,E 组：200 mJ。分别于1、3、5、7、9 d 使用 CCK-8法测定细胞生长情况,分析其增殖能力的变化。结果：培养第5天时 B～E 组细胞增殖率高于 A 组（P ＜0．05）。结论：低能量,短时间的 Er：YAG 激光照射能促进牙周膜成纤维细胞的增殖能力。     

Nd：YAG激光照射对提高人牙周膜成维细胞增殖力的作用

目的观察Nd：YAG激光对人牙周膜成纤维细胞增殖和碱性磷酸酶（ALP）活性的影响。方法采用酶消化组织块法原代培养人牙周膜成纤维细胞，并进行波形蛋白及角蛋白的免疫细胞化学染色，对所培养的细胞进行鉴定。将牙周膜成纤维细胞分组，接受不同能量密度的Nd：YAG激光照射。测定牙周膜成纤维细胞碱性磷酸酶活性并观察其生长情况。结果5个实验组的细胞增殖速度及碱性磷酸酶含量均高于对照组，其中能量密度为60j／cm^2组、80j／cm^2组、100i／cm^2组与对照组相比有统计学的差异。结论低能量密度，短时间的Nd：YAG激光照射能促进牙周膜成纤维细胞的增殖，提高碱性磷酸酶活性。     

Nd:YAG 激光与根面平整对牙龈成纤维细胞在根面附着的影响

目的 :为探讨Nd :YAG激光照射对牙周病患牙根面的生物相容性影响。方法 :应用体外细胞培养技术 ,观察激光照射等处理根面的不同方式对人牙龈成纤维细胞 (Humangingivalfibroblast,HGF)附着的影响。结果 :Nd :YAG激光照射 根面平整组 ,成纤维细胞接种 2 4h后的附着量明显高于单纯Nd :YAG激光照射组和单纯根面平整组 (P<0 .0 5 )。而单纯激光照射组 (80mj/mm2 )和单纯根面平整组细胞附着量又明显大于未处理组 (P <0 .0 5 )。结论 :用一定能量密度的Nd :YAG激光照射与根面平整术联合应用可提高HGF在患牙根面上的附着量。     

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目的    评价脉冲Nd：YAG激光治疗慢性牙周炎患者牙周袋深度（PD）和附着丧失（AL）的效果。方法    选择2008年1—6月在福建医科大学附属协和医院就诊的45例慢性牙周炎患者,每例患者至少有4个以上≥6 mm的牙周袋并且分布在2个以上口腔区域内,在接受基础检查和龈上洁治术后,随机分成3组。A组（15例）：单纯接受龈下刮治和根面平整（SRP）治疗;B组（15例）：SRP+1次激光照射治疗（Nd： YAG激光,输出功率2 W,照射时间40 s）;C组（15例）：SRP+2次激光照射治疗（Nd： YAG激光,第1次照射输出功率2 W,照射时间40 s;第2次照射输出功率1 W,照射时间20s）。每组各选择40个位点。统计在基础检查,治疗2、4和12周时各组的PD和AL。结果    从第2周时,3组的PD均明显减小。而AL的改善在第4周时可以明显观察到,且C组的效果最为明显,并一直延续到12周。结论    SRP基础上辅助2次不同能量的激光治疗对慢性牙周炎PD和AL的改善效果均明显优于单独SRP使用。     

不同时间脉冲型Nd:YAG激光照射牙周病牙根面电镜及X射线能谱分析

目的:通过对不同时间脉冲型Nd:YAG激光照射牙周病牙根表面超微结构及牙骨质层主要无机物钙(Ca)、磷(P)含量进行分析,初步探讨临床最佳激光照射时间。方法:临床选择重度牙周病病例,待拔除单根牙共25颗,25个根面,随机分为5组,对照组、激光1组、2组、3组、4组,每组5颗患牙5个根面,另选5颗离体健康阻生牙为健康组。对照组在拔牙前无激光照射,余激光组用脉冲型Nd:YAG激光分别在牙周袋内持续照射15s、30s、60s、90s后,局麻下拔除患牙,处理样品,扫描电子显微镜观察牙根面超微结构,X射线能谱仪对根面牙骨质层Ca、P含量分析,分别计算Ca/P比值,统计学处理。结果:用脉冲型Nd:YAG激光,波长532nm,0.8W输出功率,15～30s为最佳照射时间,即杀菌、玷污层被汽化,又无根面过度损伤;X射线能谱分析激光照射15～30s组,根面牙骨质层Ca/P比值分别与对照组相比,经统计学处理无统计学差异;随激光照射时间延长患牙根面出现熔融碎裂等热伤害现象,形态明显改变,但牙结石仍存。结论:当其他激光参数相对恒定时,正确掌握激光照射时间,是牙科激光技术在牙周病辅助治疗中的重要因素。     

Kr:F准分子激光对牙体硬组织的热效应研究

目的：评价Kr:F准分子激光照射牙齿后，对牙体硬组织的影响。方法；通过测量Kr:F准分子激光照射后牙齿硬组织的温度，并与Nd:YAG激光照射组进行比较。结果：10s,60s时，Kr:F准分子激光组牙齿硬组织的温度升高值明显低于Nd：YAG激光照射组（P＜0．01）。在照射10s-60s时间内，Kr:F准分子激光照射后牙齿硬组织的温度变化值也明显低于Nd:YAG激光照射组（P＜0．01）。结论：Kr:F准分子激光牙齿产热较少。     

脉冲Nd:YAG激光促进氟保护漆治疗牙齿敏感症临床观察

目的　观察脉冲Nd :YAG激光促进氟保护漆治疗牙齿敏感症的临床疗效。方法　用计算机程序控制脉冲Nd :YAG激光照射经涂一层氟保护漆的牙齿敏感症患牙 ,并分别与单纯涂一层氟保护漆或单纯脉冲Nd :YAG激光照射的疗效相比较。结果　涂氟保护漆加脉冲Nd :YAG激光照射治疗牙齿敏感症优于单纯涂保护漆或单纯脉冲Nd :YAG激光照射 ,疗效有显著性差异 (P <0 .0 5 )。结论　涂氟保护漆和脉冲Nd :YAG激光照射的联合应用是一种治疗牙齿敏感症较为有效的手段     

Effect of low-level GaAlAs laser irradiation on the proliferation rate of human periodontal ligament fibroblasts: an in vitro study

AIM: The aim of this in vitro study was to evaluate a potential stimulatory effect of low-level laser irradiation on the proliferation of human periodontal ligament fibroblasts (PDLF). MATERIALS AND METHODS: PDLF obtained from third molar periodontal ligaments were cultured under standard conditions and spread on 96-well tissue culture plates. Subconfluent monolayers were irradiated with an 809-nm diode laser operated at a power output of 10 mW in the continuous wave (cw) mode at energy fluences of 1.96-7.84 Jcm-2. The variable irradiation parameters were the time of exposure (75-300 s per well) and the number of irradiations (1-3). After laser treatment, the cultures were incubated for 24 h. The proliferation rate of the lased and control cultures was determined by means of fluorescence activity of a reduction-oxidation (REDOX) indicator (Alamar Blue Assay) added to the cell culture. Proliferation, expressed in relative fluorescence units (RFU), was determined 24, 48 and 72 h after irradiation. RESULTS: The irradiated cells revealed a considerably higher proliferation activity than the controls. The differences were significant up to 72 h after irradiation (Mann-Whitney U-test, p<0.05). CONCLUSION: A cellular effect of the soft laser application is clearly discernible. Clinical studies are needed to evaluate whether the application of low-level laser therapy might be beneficial in regenerative periodontal therapy.     

Intrapulpal temperature changes during root surface irradiation with an 809-nm GaAlAs laser

OBJECTIVE: The aim of this study was to explore, in vitro, whether the irradiation of human root surfaces with a diode laser might induce nonphysiologic intrapulpal temperature elevations and, therefore, jeopardize pulp vitality. STUDY DESIGN: The pulps were removed from human maxillary and mandibular incisors extracted for periodontal reasons. The root canals were enlarged to an apical size #60 file. The teeth were radiographed with standard dental films and a millimeter grid to determine root thickness. The thickness of dentin between the root surface and the pulp in the irradiation areas was 1, 2, and 3 mm. To determine intrapulpal temperature changes during laser irradiation, 0.5-mm K-type thermocouples were inserted. An 809 nm GaAlAs laser with a 400-micron optical fiber was used. The power output varied between 0.5 and 2.5 W in the continuous-wave mode (0 Hz). Irradiation was continued for up to 120 seconds. RESULT: Temperature elevations between 0.5 and 32.0 degrees C were registered in an energy- and time-dependent manner. Dentin thickness had a significant effect on intrapulpal temperature changes (Mann Whitney U test, P <.05), with a thinner dentin layer resulting in higher temperature elevations. CONCLUSION: Diode-laser irradiation may jeopardize pulp vitality. It must be recommended to limit power output to 0.5 W and the time of irradiation to 10 seconds when lasing the root surfaces of lower incisors and first maxillary premolars. With other teeth, a power output of 1.0 W and an exposure time of 10 seconds must not be exceeded to ensure a safe clinical application.     

Effects of Er,Cr:YSGG laser irradiation on the root surface: morphologic analysis and efficiency of calculus removal

BACKGROUND: This in vitro study was performed to determine the appropriate power output setting for an erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser used in periodontal pocket irradiation by examining the morphologic alterations of the root surfaces and the efficiency of calculus removal. METHODS: Sixty-five non-carious extracted human teeth were used in this study. For morphologic analysis of the root surface, the clean, single roots of 22 teeth were separated into 91 pieces, and these pieces were immersed in acrylic resin. The specimens with root-surface exposure were prepared and divided randomly into three groups: a control group (N=8), an irradiation without water group (no water [NW] group; N=39), and an irradiation in water to simulate the conditions in a periodontal pocket group (in water [IW] group; N=44). The power output settings for laser irradiation were 0.5, 1.0, 1.5, and 2.0 W for each group. The roughness (Ra), depth (Z), and width (X) of the disk specimens were determined after laser irradiation. Eight other single-rooted teeth were examined by scanning electron microscopy (SEM) after laser irradiation under the same conditions. Thirty-five single- or multirooted teeth with heavy subgingival calculus were used to test the efficiency of laser scaling. The efficiency of calculus removal was quantified by measuring the time needed to remove the calculus completely using the laser. RESULTS: The mean Ra and Z values in the IW group were significantly higher than in the NW group with the same power output. In addition, these values with 0.5- and 1.0-W power output settings were significantly lower than with 1.5- and 2.0-W settings in the NW and IW groups. No obvious morphologic differences could be found between the 0.5- and 1.0-W power output specimens under SEM. Additionally, thermal alterations, i.e., carbonization or melting, were completely absent in the IW group. Regarding the efficiency of calculus removal, the 0.5-W setting (0.11+/-0.036 mm2/second) was significantly inferior to the 1.0-W setting (0.27+/-0.043 mm2/second). However, there was no significant difference between 1.0- and 1.5-W (0.36+/-0.11 mm2/second). The 2.0-W setting (0.63+/-0.272 mm2/second) was much more efficient but resulted in significant morphologic alterations. CONCLUSIONS: Based on these findings, it is appropriate to use a 1.0-W power output setting with an Er,Cr:YSGG laser for root scaling. This may be done without any conspicuous morphologic alterations to the root surface and with acceptably efficient removal of calculus.     

Temperature changes induced by 809-nm GaAlAs laser at the implant-bone interface during simulated surface decontamination

The aim of the study was to investigate temperature changes at the implant-bone interface during simulated implant surface decontamination with a 809-nm gallium-aluminium-arsenid (GaAlAs) semiconductor laser. Stepped cylinder implants with a diameter of 3.8 mm and a length of 11 mm with two different surfaces (sand-blasted and acid etched, and hydroxyapatite-coated) were inserted into bone blocks cut from freshly resected pig femurs. Access holes of 0.5 mm were drilled into the bone, to allow K-type thermocouples to contact periimplant bone in different parts of the cavity. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. A 600-micrometer optic fiber was used at a distance of 0.5 mm from the implant surface. Power output varied between 0.5 and 2.5 W in the continuous wave mode. The bone block was placed into a 37 degrees C water bath in order to simulate in vivo thermal conductivity and diffusitivity of heat. Temperature elevations during irradiation were registered for a period of 120 s. In mean, the critical threshold of 47 degrees C was exceeded after 9.0 s at 2.5 W, 12.5 s at 2.0 W, 18.0 s at 1.5 W and 30.5 s at 1.0 W. Surface characteristics did not have a significant effect on temperature elevations. In an energy-dependent manner, implant surface decontamination with an 809-nm GaAlAs laser must be limited in time to allow the implant and bone to cool down. Clinical guidelines are presented to avoid tissue damage.     

In Vitro Evaluation of Dentin Hydraulic Conductance After 980 nm Diode Laser Irradiation

Background: Dentin hypersensitivity treatments are based on the physical obliteration of the dentinal tubules to reduce hydraulic conductance. The aim of the present study is to evaluate the hydraulic conductance of bovine root dentin after irradiation with a 980‐nm diode laser, with or without associated fluoride varnish. Methods: Sixty bovine root dentin specimens were divided into six groups (n = 10 in each group): G1, G3, and G5 (0.5 W, 0.7 W, and 1 W diode laser, respectively); G2, G4, and G6 (fluoride varnish application + 0.5 W, 0.7 W, and 1 W diode laser, respectively). The dentin hydraulic conductance was evaluated at four time periods with a fluxmeter: 1) with smear layer, 2) after 37% phosphoric acid etching, 3) after the treatments, and 4) after 6% citric acid challenge. After the dentinal fluid flow measurements, specimens were also evaluated for mineral composition using energy dispersive X‐ray spectroscopy (EDS). Results: Analysis demonstrated a better result with increased irradiation power (P <0.001), especially if the diode laser irradiation was associated with the application of fluoride varnish (P <0.001), ensuring a greater reduction in permeability. Considering the groups treated only with laser irradiation, the 1 W group was superior when compared with the 0.5 W and 0.7 W irradiated groups immediately after treatment (P <0.001). After citric acid testing, all groups showed similar results, except when comparing the 1 W groups with the 0.5 W groups (P = 0.04). EDS results of the irradiated groups showed an increase in the proportion of calcium and phosphorus ions, which demonstrates a superficial composition modification after laser treatments. Conclusion: Laser irradiation of exposed dentin promoted significant reduction in the dentin hydraulic conductance, mainly with higher energy densities and association with fluoride varnish.     

Antimicrobial efficacy of semiconductor laser irradiation on implant surfaces

PURPOSE: This study was conducted to investigate the antimicrobial effect of an 809-nm semiconductor laser on common dental implant surfaces. MATERIALS AND METHODS: Sandblasted and acid-etched (SA), plasma-sprayed (TPS), and hydroxyapatite-coated (HA) titanium disks were incubated with a suspension of S. sanguinis (ATCC 10556) and subsequently irradiated with a gallium-aluminum-arsenide (GaAlAs) laser using a 600-microm optical fiber with a power output of 0.5 to 2.5 W, corresponding to power densities of 176.9 to 884.6 W/cm2. Bacterial reduction was calculated by counting colony-forming units on blood agar plates. Cell numbers were compared to untreated control samples and to samples treated with chlorhexidine digluconate (CHX). Heat development during irradiation of the implants placed in bone blocks was visualized by means of shortwave thermography. RESULTS: In TPS and SA specimens, laser irradiation led to a significant bacterial reduction at all power settings. In an energy-dependent manner, the number of viable bacteria was reduced by 45.0% to 99.4% in TPS specimens and 57.6% to 99.9% in SA specimens. On HA-coated disks, a significant bacterial kill was achieved at 2.0 W (98.2%) and 2.5 W (99.3%) only (t test, P < .05). For specimens treated with CHX, the bacterial counts were reduced by 99.99% in TPS and HA-coated samples and by 99.89% in SA samples. DISCUSSION: The results of the study indicate that the 809-nm semiconductor laser is capable of decontaminating implant surfaces. Surface characteristics determine the necessary power density to achieve a sufficient bactericidal effect. The bactericidal effect, however, was lower than that achieved by a 1-minute treatment with 0.2% CHX. The rapid heat generation during laser irradiation requires special consideration of thermal damage to adjacent tissues. CONCLUSION: No obvious advantage of semiconductor laser treatment over conventional methods of disinfection could be detected in vitro.     

半导体激光根管内照射即刻杀菌效应及其影响因素的初步研究

目的 研究半导体激光对根尖周炎常见致病细菌的杀菌效果及其影响因素.方法 用半导体激光对离体牙根管内细菌悬液进行照射,采用不同照射功率或照射时间,计算其杀菌率.结果 激光输出功率1.5W时,照射1、3、5 min时,杀菌率分别为53.10％、75.18％、90.55％;照射1 min,输出功率为2.0、2 5、3.0...     

Effect of CO<Subscript>2</Subscript> laser irradiation on wound healing of exposed rat pulp

This study examined the effects of direct pulp capping treatment using super-pulsed CO₂ laser preirradiation on the wound healing process of exposed rat pulp on days 1, 3, 7, 14, and 28 postoperatively. Group 1 was irradiated with a CO₂ laser and directly capped with a self-etching adhesive system. The laser was operated in super-pulse mode (pulse duration, 200 μs; interval, 5800 μs; 0.003 J/pulse). The irradiation conditions were a power output of 0.5 W, an irradiation time of 3 s, and repeat mode (10 ms of irradiation at 10-ms intervals for a total beam exposure time of 1.5 s), defocused beam diameter of 0.74 mm (approximately 20 mm from the exposed pulp surface), energy density of 0.698 J/cm² per pulse, total applied energy of 0.75 J, and an activated air-cooling system. Group 2 was capped with the self-etching adhesive system. Group 3 was capped with commercially available calcium hydroxide, and the self-etching adhesive system was applied to the cavity. The following parameters were evaluated: pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation, and bacterial penetration. The results were statistically analyzed using the Kruskal-Wallis test for differences among the groups at each observation period (P < 0.05). There were no significant differences among the experimental groups in any parameters at any postoperative period (P > 0.05). CO₂ laser irradiation was effective in arresting hemorrhaging but showed a tendency to delay reparative dentin formation compared with the application of calcium hydroxide.     

Carbon dioxide laser irradiation stimulates mineralization in rat dental pulp cells

Aim  To examine the effect of carbon dioxide laser irradiation on mineralization in dental pulp cells.
Methodology  Rat dental pulp cells were irradiated with a carbon dioxide laser at 2 W output power for 20, 40 and 60 s, and were cultured in ascorbic acid and β-glycerophosphate containing media. Cell viability was examined 24 h after laser irradiation by a modified MTT assay. Alizarin Red S staining was performed 10 days after laser irradiation. The amounts of secreted collagen from the cells after irradiation were quantified following Sirius Red staining. The expression levels of collagen type I and HSP47, collagen-binding stress protein, were analysed by real-time PCR. HSP47 protein expression was examined by Western blotting. Statistical analysis was performed using one-way analysis of variance ( anova ) followed by the Tukey's multiple comparison test.
Results  The cell viability was not affected by laser irradiation at 2 W for up to 40 s. However, it was significantly decreased by 20% at 60 s ( P <  0.05). The amount of mineralization after 10 days of irradiation at 2 W for 40 s was significantly increased in comparison to the other conditions ( P <  0.05). The extracellular collagen production was significantly increased by 73% on day 2 and 38% on day 4 after laser irradiation ( P <  0.05). Although collagen type I gene expression was not changed by laser irradiation, HSP47 gene and protein expression was induced within 12 and 24 h, respectively.
Conclusions  These results suggested that carbon dioxide laser irradiation stimulated mineralization in dental pulp cells. The laser irradiation also increased HSP47 expression but not collagen gene expression.