Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment

Abstract The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat®) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat®, the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were banded for 4 weeks without any treatment to induce caries. 1 premolar in each pair was then extracted and analyzed. The contralateral tooth received one Duraphat® application and was extracted after another 2 weeks. In the caries development part of the study. TMR analysis showed that the Duraphat® treatment on sound enamel reduced lesion depth by 48% compared to the untreated control. In the caries progression part, no significant difference was found between the untreated teeth extracted after 4 weeks and the fluoride treated lesions extracted after another 2 weeks. CLSM images agreed well with the TMR measurements. In the fluoride treated lesions, the CLSM images showed more light scattering indicating precipitation of material.     

Nd:YAG laser and calcium sodium phosphosilicate prophylaxis paste in the treatment of dentin hypersensitivity: a double-blind randomized clinical study

Clinical Oral Investigations - This double-blind, placebo-controlled, randomized clinical trial evaluated the effectiveness of Nd:YAG laser and a calcium sodium phosphosilicate–containing...     

Imaging and non-contact profile analysis of Nd:YAG laser-irradiated teeth by scanning electron microscopy and confocal laser scanning microscopy

Two types of non-contact optical profilometers, one performing scanning electron microscopy (SEM) installed with a 3D analyzer and another performing confocal laser scanning microscopy (CLSM) were applied to evaluate imaging and surface profiles simultaneously on enamel and dentin after Nd:YAG laser irradiation. The results were correlated with a stylus profilometer. Surface roughness (Ra) was also measured. Laser was applied perpendicularly to vertical sections of human extracted caries-free molars. Analysis was done on the same spot of the same specimen by both SEM and CLSM for comparison. After irradiation, enamel produced a flake-like surface and dentin resulted in a melted globule surface. SEM and CLSM gave similar surface profiles and different image contrast. The Ra obtained by CLSM was larger than that by SEM. Both SEM and CLSM provided a non-contact evaluation of tooth structural change by laser irradiation through surface analysis in selected micro areas, which was not possible using the stylus profilometer.     

The combined occluding effect of sodium fluoride varnish and Nd:YAG laser irradiation on human dentinal tubules.

Various methods and materials used in the treatment of dentin hypersensitivity are thought to achieve a therapeutic benefit by tubule occlusion. The aim of the present study was to evaluate the combined occluding effect of sodium fluoride varnish and Nd:YAG laser irradiation on human dentinal tubules. Thirty-six dentin specimens with exposed dentinal tubule orifices were used in this study. The samples were randomly divided into four groups. Groups A, B, and C were varnished by sodium fluoride, whereas group D served as a control. Then, group C was lased by 30 mJ of Nd:YAG laser, 10 pulses/s for 2 min by light painting. Three hours later, groups B and C were brushed by an electrical toothbrush for 30 min. Under SEM observation, the control group showed numerous exposed dentinal tubule orifices, and the sodium fluoride varnished specimens showed closure of exposed dentinal tubule orifices. After electrical toothbrushing, most of the sodium fluoride varnish was brushed away, except in the specimens that were irradiated by Nd:YAG laser. Over 90% of the dentinal tubule orifices were occluded by sodium fluoride varnish combined with Nd:YAG laser irradiation.     

Occluding effect of Nd:YAG laser and different dentin desensitizing agents on human dentinal tubules in vitro: a scanning electron microscopy investigation

OBJECTIVES : This in vitro study aimed to microscopically evaluate and compare the occluding effect of the Nd:YAG laser and different dentin desensitizing agents on human dentinal tubules. MATERIALS AND METHODS : The Nd:YAG laser (SunLase? 800) and four commercially available and professionally applied dentin desensitizers (Gluma? desensitizer, Tenure Quick?, Quell? desensitizer, and VivaSens?) were investigated in this study. Sixty-four extracted intact human molars were used. Each dentin surface was divided by shallow indentation into two halves, one of which was used for treatment and the other of which served as a control. The dentin surfaces were etched to remove any smear plugs and to mimic the open dentinal tubules of sensitive dentin using 0.5 M ethylenediaminetetraacetic acid (pH 7.4) for two minutes (applied with a microbrush) and then rinsed with an air-water syringe for 30 seconds. The laser samples (n=16) were randomly divided into four groups of four samples each. These groups were the step-up technique group, the 14-day group, the one-minute group, and the two-minute group. Forty-eight samples were treated with the four tested desensitizing agents and were randomly divided into four groups (n=12/group). Each group was further subdivided into three subgroups (n=4). Samples of the first subgroup were treated for 14 days, while those of the second subgroup were treated once. Samples of the last subgroup were fractured longitudinally after a single treatment. All of the samples were then examined under a scanning electron microscope. RESULTS : The Nd:YAG laser-irradiated dentin showed reduction or complete obliteration of the dentinal tubule lumen; thus, the treatment modified the original dentinal structure. The lased dentin surface in the two-minute group showed bubble-like changes in the area of the dentinal tubules' orifices. Statistically, the two-minute group was found to have a significantly higher percentage of partially or fully occluded tubules than did the one-minute group. All of the studied desensitizing agents produced occlusion of the dentinal tubules; however, the appearance of the precipitates, the level of coverage, and the degree of dentinal occlusion varied among the tested products. CONCLUSION : Throughout the specified period of this study, occlusion and/or narrowing of the open dentinal tubules have been successfully achieved with both treatment approaches.     

Treating cervical dentin hypersensitivity with fluoride varnish: a randomized clinical study

BACKGROUND: This subject-blind randomized clinical trial tested the efficacy of a new 5 percent sodium fluoride varnish (AllSolutions Fluoride Varnish, Dentsply Professional, York, Pa.) for treatment of cervical dentin hypersensitivity. The authors also compared the test varnish with a control fluoride varnish (Duraphat, Colgate Oral Pharmaceuticals, New York City). METHODS: The study involved application of the test or control varnish to 19 subjects (59 teeth) with tooth sensitivity. The authors applied each product once to each tooth, following manufacturers' instructions. They used a visual analog scale (VAS) to assess subjects' responses to compressed air and ice stimuli at six weeks before baseline, at baseline and at two, eight and 24 weeks after treatment. RESULTS: Mean VAS scores for teeth receiving the test varnish dropped from 34.9 (air) and 68.0 (ice) at baseline to 26.3 (air) and 54.7 (ice) at two weeks after treatment. Mean scores at 24 weeks were 20.6 (air) and 34.8 (ice), representing statistically significant differences from baseline values. For the control varnish, mean VAS scores dropped from 36.9 (air) and 64.2 (ice) at baseline to 32.9 (air) and 47.2 (ice) at two weeks, and to 20.8 (air) and 40.3 (ice) at 24 weeks. The authors analyzed the data for statistical significance, accounting for clustering of teeth within subjects. CONCLUSION AND CLINICAL IMPLICATIONS: The test varnish was effective in reducing cervical dentin hypersensitivity. However, the efficacy was not significantly different from that of the control varnish.     

Nd:YAG激光治疗牙齿感觉过敏症

牙齿感觉过敏症是口腔科的常见病和多发病。应用Nd:YAG激光技术治疗牙齿感觉过敏症已经取得了较好的疗效。有并且在这方面的研究成果正不断出现，成为一个热点，目前主要的研究集中在激光治疗的效果，牙髓的反应和对牙齿硬组织的影响方面，本文就激光治疗牙齿感觉过敏症的机制，疗效和失败的因素作一简要综述。     

Combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine

ObjectiveThis study evaluated the combined effect of fluoride varnish to Er:YAG or Nd:YAG laser on permeability of eroded root dentine.DesignSixty slabs of bovine root dentine (2 × 2 × 2 mm) were eroded with citric acid 0.3% (pH 3.2) during 2 h and then kept in artificial saliva during 24 h. Specimens were randomly assigned in 6 groups (n = 10), to receive the following treatments: fluoride varnish; fluoride varnish + Er:YAG laser; fluoride varnish + Nd:YAG laser; non-fluoride varnish; non-fluoride varnish + Er:YAG laser; non-fluoride varnish + Nd:YAG laser. The Er:YAG (100 mJ, 3 Hz) and Nd:YAG (70 mJ, 15 Hz) were applied for 10 s. Specimens were subjected to further erosive challenges with citric acid 0.3% 4×/day, during 1 min, for 5 days, remaining in artificial saliva between cycles. Dentin permeability was then assessed. Two-way ANOVA demonstrated no significant interaction between laser and varnish (p = 0.858).ResultsNo effect was also detected for the main factor varnish (p = 0.768), while permeability of eroded root dentin was significantly lower when such substrate was laser-irradiated, no matter the laser source (p < 0.001).ConclusionsThis study concluded that Er:YAG and Nd:YAG lasers can be employed to control the permeability of eroded root dentin, regardless of fluoride varnish application.     

Treatment of dentin hypersensitivity by Nd:YAG laser

BACKGROUND, AIMS: Promising results using Nd:YAG laser against dentin hypersensitivity have been reported. The aim of this double-blind, controlled, split-mouth designed clinical trial was to assess the effect of a single Nd:YAG laser application on alleviating hypersensitivity. METHODS/RESULTS: Seventeen subjects participated in the study. Each of them had two teeth treated; one with the laser activated and one with nonactivated (placebo), for 2 min The assessment of pain was performed by a VAS, after an air blast at baseline immediately after treatment, at 1 week, 4 weeks and 16 weeks. Mean values of VAS for test and control teeth were compared by paired t-test (alpha = 0.05). The results showed mean baseline VAS values of 6.59 (+/- 1.65) and 6.14(+/- 1.95) for test and control teeth, respectively. Immediately after treatment, these values decreased to 4.09(+/- 2.28) and 3.89(+/- 2.11), respectively. After 1 week, 4 weeks and 16 weeks the mean values for test and control teeth were 3.85 +/- 2.36, 4.03 +/- 1.95, 3.60 +/- 2.66, and 4.44 +/- 2.56, 3.41 +/- 2.30, 3.42 +/- 2.30, respectively. There were no statistically significant differences between test and control at any time. However, both groups improved significantly (P < 0.05) from baseline to immediately after application, and at 1 week, 4 weeks and 16 weeks, respectively. The changes that occurred between immediately after application and 1 week, 4 weeks and 16 weeks, respectively, were not statistically significant. CONCLUSION: It is concluded that the effect of treatment of hypersensitive teeth with Nd:YAG laser is not different from placebo. The observed effects seem to last for at least 16 weeks.     

脉冲Nd:YAG激光照射牙本质后与复合树脂粘结的初步研究

目的 :筛选脉冲Nd :YAG激光应用于牙本质粘结的最佳输出参数 ,并与传统的表面处理方法进行对照 ,探讨脉冲Nd :YAG激光的应用前景。方法 :选取 3 5个新鲜健康的离体人前磨牙 ,随机分成 5组 ,分别用 5组激光剂量照射牙本质表面 ,复合树脂粘结 ,测定抗拉粘结强度。另选取 2 7个离体牙 ,随机分成 3组 :激光组 (前面筛选的 )、磷酸酸蚀组和 10 3液组。每组随机抽取 2个样本 ,垂直于粘结界面剖开 ,扫描电镜观察粘结界面的形态学 ;其余样本用于测定抗拉粘结强度 ,并观察断面的形态学改变。结果 :当激光输出参数为 1W、15Hz时 ,抗拉粘结强度最高〔( 5 .74± 2 .86)MPa〕。在对比研究中 ,激光组的抗拉粘结强度均值最高 ,但与其它 2组无统计学差异 (P >0 .0 5 )。界面与断面结果 ,激光组的混合层最厚 ( 10～ 3 0 μm) ,激光组和 10 3液组断面残留的复合树脂明显多于酸蚀组。结论 :脉冲Nd :YAG激光作为牙本质表面处理方法的最佳输出参数为 1W、15Hz ,但抗拉粘结强度与 10 3液组和磷酸酸蚀组无显著性差异     

Nd:YAG激光治疗牙本质过敏症的机制和应用进展

牙本质过敏症是口腔领域一种常见的症状,目前尚未有十分理想的治疗方法.在众多治疗方法中,激光脱敏因其疗效明确、作用迅速等优点,引起了人们的广泛关注,其中Nd:YAG激光是应用最为广泛的一种激光.该文对Nd:YAG激光治疗牙本质过敏症的具体机制和应用进展作一综述,以期为临床应用及科学研究提供参考.     

Nd:YAG laser biostimulation of bisphosphonate-associated necrosis of the jawbone with and without surgical treatment

Bisphosphonate-associated osteonecrosis was first reported in 2003 and is getting common. Size of lesions, symptoms, and duration of time between starting bisphosphonates and the development of bone necrosis vary. There is currently no effective treatment. We describe our preliminary results with 19 patients affected by bisphosphonate-associated osteonecrosis of the jaws who were treated conventionally with surgical or medical treatment alone or in combination with neodimium: yttrium-aluminium-garnet (Nd:YAG) laser. Clinical variables such as symptoms, presence of pus, and closure of mucosal flaps before and after treatment were evaluated to establish the effect of the laser irradiation. We treated nine patients with laser biostimulation with or without surgical treatment, and in this group there were eight clinical successes and one symptomatic improvement, with a clinical finding better than ones without laser biostimulation (ten patients, five clinical successes, and one symptomatic improvement).     

Effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting dentin caries in Chinese pre-school children

Untreated dental caries in Chinese pre-school children is common. This prospective controlled clinical trial investigated the effectiveness of topical fluoride applications in arresting dentin caries. Three hundred seventy-five children, aged 3-5 years, with carious upper anterior teeth were divided into five groups. Children in the first and second groups received annual applications of silver diamine fluoride solution (44,800 ppm F). Sodium fluoride varnish (22,600 ppm F) was applied every three months to the lesions of children in the third and fourth groups. For children in the first and third groups, soft carious tissues were removed prior to fluoride application. The fifth group was the control. Three hundred eight children were followed for 30 months. The respective mean numbers of arrested carious tooth surfaces in the five groups were 2.5, 2.8, 1.5, 1.5, and 1.3 (p < 0.001). Silver diamine fluoride was found to be effective in arresting dentin caries in primary anterior teeth in pre-school children.     

脉冲Nd：YAG激光照射对牙本质通透性的影响

应用牙本质通透性测定装置，定量测定脉冲Ｎｄ：ＹＡＧ激光在不同参数条件下照射后对牙本质通透性的影响。结果表明：在４个不同的激光参数条件下，激光照射后牙本质通透性均较照射前呈显著性下降，其中以每秒１５个脉冲０．７５Ｗ的２．０ｍｉｎ组和每秒１５个脉冲１．００Ｗ的２．０ｍｉｎ组下降最为明显，与每秒１５个脉冲０．７５Ｗ的１．５ｍｉｎ组之间呈显著性差异（ＦＫＰＦＦ＜０．０５）。提示脉冲Ｎｄ：ＹＡＧ激光在一定参数条件下照射，可熔融和封闭牙本质小管，是治疗牙齿敏感症的有效手段之一     

Nd:YAG激光治疗牙本质敏感的研究进展

牙本质敏感是口腔常见病症,患病率高,影响患者口腔健康与生活质量。激光治疗牙本质敏感获得良好疗效,其中Nd:YAG激光成为激光治疗牙本质敏感的首选。本文就目前Nd:YAG激光治疗牙本质敏感的研究进展进行综述。     

Evaluation of root canal dentin after Nd:YAG laser irradiation and treatment with five different irrigation solutions: a preliminary study

This study evaluated in vitro any changes in the morphology and mineral content of root canal dentin after treatments with Nd:YAG laser irradiation and 5 different irrigation solutions. The groups of extracted single-rooted human teeth were exposed to sterile saline solution, 5.25% NaOCl, 3% H2O2, 15% ethylenediaminetetraacetic acid, 2% chlorhexidine gluconate, and Nd:YAG laser irradiation. All prepared teeth were bisected longitudinally; half of each tooth was used for wavelength dispersive x-ray fluorescence spectrometry analysis to assess the mineral content. The other half was studied by using scanning electron microscopy to analyze the surface of the dentin. The results showed that the calcium level and calcium/phosphorus ratio decreased significantly with the NaOCl irrigation solutions (p < .05), suggesting the presence of changes at molecular level. Significant differences among the test groups were also observed in the scanning electron microscopy evaluation (p < .05). The lowest scores for root cleaning were obtained by using ethylenediaminetetraacetic acid followed by Nd:YAG laser treatment.     

Phase, compositional, and morphological changes of human dentin after Nd:YAG laser treatment

Although techniques for repairing root fracture have been proposed, the prognosis is generally poor. If the fusion of a root fracture by laser is possible, it will offer an alternative to extraction. Our group has attempted to use lasers to fuse a low melting-point bioactive glass to fractured dentin. This report is focused on the phase, compositional, and morphological changes observed by means of X-ray diffractometer, Fourier transforming infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy in human dentin after exposure to Nd:YAG laser. The irradiation energies were from 150 mJ/ pulse-10 pps-4 s to 150 mJ/pulse-30 pps-4 s. After exposure to Nd:YAG laser, dentin showed four peaks on the X-ray diffractometer that corresponding to a-tricalcium phosphate (TCP) and beta-TCP at 20 = 30.78 degrees/34.21 degrees and 32.47 degrees/33.05 degrees, respectively. The peaks of a-TCP and beta-TCP gradually increased in intensity with the elevation of irradiation energy. In Fourier transforming infrared analysis, two absorption bands at 2200 cm(-1) and 2015 cm(-1) could be traced on dentin treated by Nd:YAG laser with the irradiation energies beyond 150 mJ/pulse-10 pps-4 s. The energy dispersive X-ray results showed that the calcium/phosphorus ratios of the irradiated area proportionally increased with the elevation of irradiation energy. The laser energies of 150 mJ/ pulse-30 pps-4 s and 150 mJ/pulse-20 pps-4 s could result in the a-TCP formation and collagen breakdown. However, the formation of glass-like melted substances without a-TCP at the irradiated site was induced by the energy output of 150 mJ/ pulse-10 pps-4 s. Scanning electron micrographs also revealed that the laser energy of 150 mJ/ pulse-10 pps-4 s was sufficient to prompt melting and recrystallization of dentin crystals without cracking. Therefore, we suggest that the irradiation energy of Nd:YAG laser used to fuse a low melting-point bioactive glass to dentin is 150 mJ/ pulse-10 pps-4 s.     

Nd:YAG激光对不同水门汀与牙本质间边缘微渗漏的影响

目的:评价Nd:YAG激光对不同水门汀与牙本质之间边缘微渗漏的影响。方法:选用人离体磨牙48颗,间接法制作树脂嵌体,随机分为激光组和对照组,激光组使用80 mJ、10 Hz脉冲Nd:YAG激光照射后,分别用6种水门汀粘结树脂嵌体。全部试件放在37℃生理盐水中7 d,并冷热循环300次后,放置于0.5%的品红溶液中染色24 h,沿嵌体长轴纵剖后在根管显微镜下观察微渗漏情况,采用SPSS 17.0软件包对数据进行统计学处理。结果:6组牙本质经Nd:YAG激光照射后微渗漏程度均有降低趋势,且前2种水门汀有统计学差异(P<0.05)。另外,树脂水门汀与牙本质之间的微渗漏程度比水基水门汀低。结论:80 mJ、10 Hz脉冲Nd:YAG激光照射牙本质壁,可提高洞壁的密合度,减少微渗漏。     

Nd:YAG激光治疗牙本质过敏症的临床疗效观察

目的 :探讨Nd :YAG激光治疗牙本质过敏症的疗效。方法 :15 3例患者的 2 70颗患牙 ,随机分为 2组 ,分别用Nd :YAG激光和Gluma脱敏剂进行治疗后观察疗效。结果 :实验组治愈率为 92 .5 9% ,有效率为94.0 7% ;对照组治愈率为 49.62 % ,有效率为 71.84%。结论 :2种治疗方法的疗效有显著性差异 (P <0 .0 1) ,激光治疗牙本质过敏的效果优于Gluma脱敏剂。