Belcheva A, El Feghali R, Nihtianova T, Parker S
Department of Pediatric Dentistry, Faculty of Dental medicine, Medical University of Plovdiv, Plovdiv, Bulgaria.
Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.
Lasers Med Sci. 2018 Jul;33(5):1009-1017. doi: 10.1007/s10103-018-2446-4. Epub 2018 Jan 21.
The aim of this in-vitro study was to evaluate positive effects of the carbon dioxide laser (CO, 10,600 nm) with acidulated phosphate fluoride (APF) gel on enamel acid resistance. Twenty extracted human third molars (40 surfaces) were randomly assigned into four groups: group C, untreated control; group L, CO laser alone group; group F, APF 1.23% fluoride gel; and group FL, APF 1.23% gel and laser. Samples from group L were irradiated with a CO laser for 30s. The parameter settings used were average power, 0.73 W; time on, 100 μs; time off, 40 ms; tip-to-tissue distance, 20 mm; tip diameter 700 μm; and energy density with movements, 5 J/cm. Samples from group F were treated with the APF gel for 4 min, and the gel was washed off with distilled water. The enamel samples from group FL were treated with APF gel for 4 min and then irradiated with the CO laser for 30s without removing the gel. Each enamel sample was placed in 50 ml soft drink (pH = 2.75) for 10 min then rinsed with deionized water and stored in artificial saliva at 37 °C for 1 h. Samples were assessed for Vickers hardness number (VHN) before and after treatments and subjected to SEM analysis. Data were analyzed using a one-way analysis of variance (ANOVA) and Tukey's test (α < 0.05). After the acid challenge, the untreated C group was demineralized to a great extent and the enamel surface was with the lowest mean score of microhardness. The observed VHN in the control (C group) had a mean value of 176.13, the scores in the CO laser group (L group) were with mean value of 238.40, the F group with a mean value of 218.45, and the fluoride-treated and laser-irradiated FL group-with a mean of 268.28 VHN. Paired t test performed to compare groups C, L, F, and FL has shown that group FL has greater resistance to decrease in microhardness of dental enamel (P ≤ 0.05) on exposure to acidic protocol. After the acid challenge, the fluoride-treated and laser-irradiated samples (group FL) showed the least diminution in enamel surface microhardness. The sub-ablative carbon dioxide laser irradiation in combination with fluoride treatment is more effective in protecting enamel surface and resisting demineralization than CO laser irradiation or fluoride alone.
本体外研究的目的是评估二氧化碳激光（CO，10600纳米）联合酸化磷酸氟（APF）凝胶对牙釉质抗酸性的积极影响。将20颗拔除的人类第三磨牙（40个表面）随机分为四组：C组，未处理的对照组；L组，仅二氧化碳激光组；F组，1.23% APF氟凝胶组；FL组，1.23% APF凝胶和激光组。L组的样本用二氧化碳激光照射30秒。使用的参数设置为：平均功率0.73瓦；开启时间100微秒；关闭时间40毫秒；尖端与组织距离20毫米；尖端直径700微米；移动时的能量密度5焦/平方厘米。F组的样本用APF凝胶处理4分钟，然后用蒸馏水冲洗掉凝胶。FL组的牙釉质样本用APF凝胶处理4分钟，然后在不除去凝胶的情况下用二氧化碳激光照射30秒。每个牙釉质样本置于50毫升软饮料（pH = 2.75）中10分钟，然后用去离子水冲洗，并在37℃的人工唾液中保存1小时。在处理前后对样本进行维氏硬度值（VHN）评估，并进行扫描电子显微镜分析。数据采用单因素方差分析（ANOVA）和Tukey检验（α < 0.05）进行分析。酸蚀后，未处理的C组脱矿严重，牙釉质表面显微硬度平均得分最低。对照组（C组）观察到的VHN平均值为176.13，二氧化碳激光组（L组）的得分平均值为238.40，F组平均值为218.45，氟处理和激光照射的FL组平均值为268.28 VHN。对C、L、F和FL组进行配对t检验表明，FL组在暴露于酸性方案时对牙釉质显微硬度降低的抵抗力更强（P≤0.05）。酸蚀后，氟处理和激光照射的样本（FL组）牙釉质表面显微硬度降低最少。亚消融性二氧化碳激光照射联合氟处理在保护牙釉质表面和抵抗脱矿方面比单独的二氧化碳激光照射或氟处理更有效。
