de Oliveira Ortolan Andréa Soares, Torres Carolina Paes, Gomes-Silva Jaciara Miranda, de Menezes-Oliveira Maria Angélica Hueb, Pécora Jesus Djalma, Palma-Dibb Regina Guenka, Borsatto Maria Cristina
Department of Pediatric Clinic, Preventive and Social Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
Photomed Laser Surg. 2009 Dec;27(6):885-90. doi: 10.1089/pho.2008.2358.
To evaluate the ablation capacity of different energies and pulse repetition rates of an erbium-doped yttrium aluminium garnet (Er:YAG) laser on primary dentin by assessing mass loss and to analyze the surface morphology using scanning electron microscopy (SEM).
Previous studies have demonstrated the ability of the Er:YAG laser to ablate dentin substrate.
Forty-eight sound primary molars were bisected in the mesiodistal direction. The dentin surfaces were flattened, and initial mass (mg) was obtained. A 4-mm2 area was delimited. Specimens were randomly assigned to 12 groups according to the combination of energy (160, 200, 250, and 300 mJ) and pulse repetition rate (2, 3, and 4 Hz). Er:YAG laser irradiation was performed for 20 s. After irradiation, the final mass was obtained, and specimens were prepared for SEM. The data obtained by subtracting the final mass from the initial mass were statistically analyzed using analysis of variance and Tukey test (alpha=0.05).
The pulse repetition rate of 4 Hz provided greater mass loss, and it was different from 2 Hz and 3 HZ. The energy of 300 mJ resulted in greater mass loss, similar to 200 and 160 mJ. SEM micrographs showed dentinal tubule obliteration, structural alterations, and the presence of cracked areas in all specimens.
The settings of 160, 200, and 250 mJ at 2 and 3 Hz promoted a good ablation rate with fewer surface alterations in primary dentin.
通过评估质量损失来评价掺铒钇铝石榴石（Er:YAG）激光不同能量和脉冲重复频率对乳牙本质的消融能力，并使用扫描电子显微镜（SEM）分析表面形态。
先前的研究已证明Er:YAG激光能够消融牙本质基质。
将48颗完好的乳牙沿近远中方向一分为二。将牙本质表面平整，获取初始质量（mg）。划定一个4平方毫米的区域。根据能量（160、200、250和300 mJ）和脉冲重复频率（2、3和4 Hz）的组合，将样本随机分为12组。用Er:YAG激光照射20秒。照射后，获取最终质量，并制备样本用于SEM分析。通过将初始质量减去最终质量得到的数据，使用方差分析和Tukey检验进行统计学分析（α = 0.05）。
4 Hz的脉冲重复频率导致更大的质量损失，且与2 Hz和3 Hz不同。300 mJ的能量导致更大的质量损失，与200和160 mJ相似。SEM显微照片显示所有样本中均有牙本质小管闭塞、结构改变以及裂纹区域。
2 Hz和3 Hz时160、200和250 mJ的参数设置在乳牙本质中促进了良好的消融率，且表面改变较少。
