Application of Laser to Endodontic Micro-Surgery

1：初始成纤维细胞与铒YAG激光照射牙本质的附着本研究的目的是评估在酸、低水平铒YAG激光照射或激光照射加抗生素治疗后，切除牙本质表面的生物相容性。取单根人牙本质盘分为两组：(1)激光组，Er: YAG激光照射（30mJ/脉冲，10pps, 60s）；(2) L-MTAD组，与激光组相同，采用激光照射加强力霉素、四环素异构体和柠檬酸混合治疗；(3) RC-Prep组，以EDTA凝胶或乳膏（RC-Prep）治疗；(4)对照组，不处理。每次处理后，牙本质盘与培养至亚融合的NIH/3T3成纤维细胞在添加10%胎牛血清和抗生素的Dulbecco改良Eagle培养基中孵育。各组间附着细胞数以5%的显著性水平进行统计学分析。在扫描电镜下观察到更多的牙本质表面形态。通过计数、组织学观察和扫描电镜，在细胞培养处理后的4、8和16小时三个代表性时间点评估细胞附着。附着细胞数显著高于对照组（p< 0.05）。在16h时，激光组比RC-Prep组和对照组明显增高（0.05）。激光组树突状细胞仅在8h时通过扫描电镜观察到成纤维细胞的延伸。组织学分析显示，激光照射后牙本质表面附着细胞明显增多。2 . Er: YAG和Nd: YAG激光照射后牙本质表面修饰对成纤维细胞粘附的影响本实验通过分析Er: YAG和Nd: YAG激光照射后牙本质表面的形貌和粗糙度，并与常规毛刺处理后的结果进行比较，评估成纤维细胞与牙本质表面的粘附性。本研究使用35颗新拔的单根人牙，牙尖完全成形。拔除每颗牙的根尖，用低速锯制作牙本质盘。牙本质盘分为三组。A组不进行治疗，B组采用Er: YAG激光照射（60mJ/脉冲，10pps, 60s）， C组采用Nd: YAG激光照射（60mJ/脉冲，10pps, 60s）。激光照射后，牙本质盘与Dulbecco改良Eagle培养基中培养的NIH/3T3成纤维细胞孵育。用扫描电镜观察牙本质表面形貌，用激光共聚焦扫描显微镜测量牙本质表面粗糙度。利用扫描电镜（SEM）分析和WST实验，在12和24h的孵育期评估细胞粘附性。统计学分析采用方差分析，显著性水平为5% （p< 0.05）。05)。形态学分析和粗糙度测量表明，Er: YAG激光照射组（B组）牙本质表面均较A、c组粗糙。Er: YAG激光照射组培养12h后，附着细胞变平，丝状足扩张贴附在牙本质上。在12和24h后，B组（Er: YAG）的附着细胞数量是各组中最多的。少

1 : Initial fibroblast cell attachment to Erbium : YAG laser-irradiated dentinThe purpose of this study was to evaluate the biocompatibilities of resected dentin surfaces after treatment with acid, low-level Er : YAG laser irradiation, or laser irradiation plus antibiotics. Dentin disks obtained from single-rooted human teeth were divided into the following groups :(1) Laser group, treated with Er : YAG laser irradiation(30mJ/pulse, 10pps, 60s);(2) L-MTAD group, treated with laser irradiation as in the laser group plus a mixture of doxycycline, tetracycline isomer and citric acid ;(3) RC-Prep group, treated with EDTA gel or cream(RC-Prep); and(4) Control group, left untreated. After each treatment, the dentin disks were incubated with NIH/3T3 fibroblasts cultured to subconfluency in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and antibiotics. The number of attached cells among the groups was statistically analyzed at the 5% significance level. The dentin … More surface morphologies was observed under scanning electron microscopy(SEM). Cell attachments were evaluated at three representative time points : 4, 8, and 16h following cell culture treatment by counting assays, histological observation, and SEM. The number of attached cells was significantly higher(p<0. 05) in the Laser group than in the RC-Prep and Control groups at 16h. Dendritic cell extension of the fibroblasts was only observed in the Laser group at 8h by SEM. In the histological analyses, significantly more attached cells were found on the dentin surfaces treated with laser irradiation.2 : Effects of dentin surface modifications treated with Er : YAG and Nd : YAG laser irradiation on fibroblast cell adhesionThis in vitro study evaluated fibroblast adhesion to dentin surfaces treated with Er : YAG and Nd : YAG laser irradiation by analyzing the morphology and roughness of dentin surfaces and compared the results with those of the conventional treatment with burs. Thirty-five freshly extracted single-rooted human teeth with fully formed apices were used in this study. The root apex of each tooth was removed and dentin disks were prepared using a low-speed saw. Dentin disks were divided into three groups. Group A was left untreated, Group B was treated with Er : YAG laser irradiation(60mJ/pulse, 10 pps, 60s), and Group C was treated with Nd : YAG laser irradiation(60mJ/pulse, 10pps, 60s). After laser irradiation, the dentin disks were incubated with NIH/3T3 fibroblasts cultured in Dulbecco's modified Eagle's medium. A morphological analysis of the dentin surface was observed under SEM, and surface roughness was measured using a confocal laser scanning microscopy. Cell adhesion was evaluated at 12and 24h of incubation periods using SEM analysis and WST assay. The statistical analysis was undertaken using ANOVA at a 5% level of significance(p<0. 05). Morphological analysis and roughness measurement showed that all dentin surfaces treated with Er : YAG laser irradiation(Group B) were rougher than those in Groups A and C. In the Er : YAG-irradiated group, attached cells were flattened and attached to the dentin by expanded filopodia after 12h of culture. Group B(Er : YAG) exhibited the greatest number of attached cells among all groups after 12 and 24h. Less