Saberi Sogol, Seyed Jabbari Doshanlo Sooreh, Bagheri Hossein, Mir Mohammad Rezaei Susan, Shahabi Sima
Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Periodontics Department, School of Dentistry, Shahid Beheshti University of Medical Science, Tehran, Iran.
J Lasers Med Sci. 2018 Summer;9(3):188-193. doi: 10.15171/jlms.2018.34. Epub 2018 Jul 28.
Laser irradiation of dentin surface can affect its surface topography and roughness. Atomic force microscopy (AFM) is among the most efficient tools for determination of surface topography of natural biomolecules in nano-scales. Surface roughness affects plaque retention especially in the cervical region. This study aimed to assess and compare the obstruction of dentinal tubules and dentin surface roughness after irradiation of erbium: yttrium aluminum garnet (Er:YAG ) and CO2 lasers for treatment of dentin hypersensitivity (DH). Five disc-shaped samples measuring 3 mm in thickness were fabricated by horizontal sectioning of the cervical area of five extracted human molars using a low speed saw. Each disc was divided into 3 segments by a bur under water coolant. The three segments of each disc were placed on a glass slide. First segment: No intervention (control group). Second segment: Er:YAG laser irradiation (2940 nm, 50 mJ, 10 Hz and 0.5 W, 30 seconds) along with water coolant. Third segment: CO2 laser irradiation (10600 nm, 80 Hz, 0.3 W, 30 seconds) along with water coolant. After that, the surfaces underwent non-contact AFM. The diameters of dentinal tubules as well as surface roughness were then measured and statistically analyzed using repeated measures ANOVA. The surface roughness parameters (Ra, Rq) showed increased roughness after laser irradiation and this increase in roughness after Er:YAG laser application was significant compared to the control group (P=0.048). However, CO2 laser caused no significant change in surface roughness. Also, after Er:YAG laser application, fewer open dentinal tubules were observed and the remaining open tubules had a smaller diameter. Based on the results, Er:YAG laser irradiation obstructs the dentinal tubules and increases the dentin surface roughness. This increase in surface roughness can cause microbial plaque retention and increase the risk of caries and periodontal disease. Application of CO2 laser (compared to Er:YAG) lead to slight but clinically significant obstruction of dentinal tubules and surface roughness.
牙本质表面的激光照射会影响其表面形貌和粗糙度。原子力显微镜（AFM）是测定纳米尺度天然生物分子表面形貌最有效的工具之一。表面粗糙度会影响牙菌斑的附着，尤其是在颈部区域。本研究旨在评估和比较铒：钇铝石榴石（Er:YAG）激光和二氧化碳激光照射治疗牙本质过敏症（DH）后牙本质小管的阻塞情况和牙本质表面粗糙度。使用低速锯对五颗拔除的人类磨牙的颈部区域进行水平切片，制作了五个厚度为3毫米的圆盘形样本。每个圆盘在水冷条件下用钻头分为3段。每个圆盘的三段分别放置在载玻片上。第一段：不干预（对照组）。第二段：Er:YAG激光照射（2940纳米，50毫焦，10赫兹和0.5瓦，30秒）并伴有水冷。第三段：二氧化碳激光照射（10600纳米，80赫兹，0.3瓦，30秒）并伴有水冷。之后，对表面进行非接触式AFM检测。然后测量牙本质小管的直径以及表面粗糙度，并使用重复测量方差分析进行统计分析。表面粗糙度参数（Ra、Rq）在激光照射后显示粗糙度增加，与对照组相比，Er:YAG激光照射后粗糙度的增加具有显著性（P = 0.048）。然而，二氧化碳激光对表面粗糙度没有显著影响。此外，在应用Er:YAG激光后，观察到开放的牙本质小管较少，剩余开放小管的直径较小。基于这些结果，Er:YAG激光照射会阻塞牙本质小管并增加牙本质表面粗糙度。这种表面粗糙度的增加会导致微生物牙菌斑附着，并增加龋齿和牙周疾病的风险。与Er:YAG激光相比，二氧化碳激光的应用导致牙本质小管有轻微但临床上显著的阻塞和表面粗糙度变化。
