用色度学方法研究牙齿漂白剂增白牙齿的效果

目的:研究牙齿漂白剂增白牙齿的效果,建立用色度学分析手段研究牙齿漂白剂增白牙齿效果的方法。方法:将166名受试者随机分配到三个实验组,经过两周的临床实验,分别用Vita比色板法和数码照像计算机色度分析系统,分析并比较实验前后牙面Vita色度和色差△Eab的变化。结果:118名受试者完成实验,三个实验组间受试者在性别、年龄、吸烟量等基本情况方面分布均衡;两种漂白剂使用两周后,牙面Vita色度与实验前比较相差非常显著(P<0.01),而空白对照组与实验前比较相差不显著(P>0.05);与空白对照组比较,两漂白剂组△Eab值相差非常显著(P<0.01),两漂白剂组之间△Eab值相差不显著(P>0.05)。结论:建立了用色度学分析手段研究牙齿漂白剂增白牙齿效果的方法,用该方法研究表明,两种漂白剂都具有增白牙齿的效果,并且它们增白牙齿的效果之间没有差别。     

非侵入性牙齿美白技术的研究进展

牙齿美白技术是口腔医学美学的代表技术之一,被广泛应用于临床.随着人们对口腔美学需求的增加,研究者对牙齿美白技术及其相关问题的认识越来越清晰,也越来越广泛和深入.本文针对非侵入性牙齿美白技术的相关研究做一个阶段性的回顾,包括牙齿美白技术的发展、种类、效果评价、安全性、延伸应用及药物的联合应用等.     

Efficacy of tooth whitening with different calcium phosphate‐based formulations

The aim of this in‐vitro study was to evaluate the efficacy of tooth whitening using different calcium phosphate‐based formulations. Teeth were treated with three different hydroxyapatite preparations at different concentrations and with two control preparations; each tooth was treated a total of three times. After application of the last material, hydrodynamic shear force was applied to mimic mechanical loading. After each treatment, tooth color was measured using a dental spectrophotometer, and the mean changes in L*a*b* values between different measurements were expressed as ?E. The results indicated significant differences between the materials, but neither dose‐ nor time‐dependent associations were found. The suspension containing tricalcium phosphate (10 wt%) showed the most obvious color change (?E = 2.20 ± 0.90), while the suspension containing zinc‐carbonate‐apatite (20 wt%) showed the least obvious color change (?E = 0.91 ± 0.50). Calcium phosphate‐based formulations that can adhere to the enamel surface and contribute to tooth whitening have promising tooth‐whitening potential.     

New discoveries and directions for medical, dental and dental hygiene research: low temperature atmospheric pressure plasma

Abstract:  The study of plasma integrates physics, chemistry, biology, and engineering, and has recently engaged medicine and dental hygiene in research efforts. The study of plasma holds promise for a myriad of applications ranging from lasers and electronics, hazardous waste management, decontamination, sterilization and disinfection of foods, soil, water, instruments, to medical uses in wound healing and treating certain types of tumours and cancers. Plasma represents a new state-of-the-art sterilization and disinfection treatment for certain oral and enviornmental pathogens, heat-sensitive materials, contaminated medical waste, hard and soft surfaces, and ventilation systems may assist health care facilities in the management of various health concerns. The role that Low Temperature Atmospheric Pressure Plasma (LTAPP) could play in the inactivation of pathogenic microorganisms might prove to be a new, faster, noncorrosive, more economical alternative, as well as support green healthcare.     

Effects of non‐thermal atmospheric pressure pulsed plasma on the adhesion and durability of resin composite to dentin

This study investigated the effect of low‐power, non‐thermal atmospheric pressure plasma (NT‐APP) treatments, in pulsed and conventional modes, on the adhesion of resin composite to dentin and on the durability of the bond between resin composite and dentin. A pencil‐type NT‐APP jet was applied in pulsed and conventional modes to acid‐etched dentin. The microtensile bond strength (MTBS) of resin composite to dentin was evaluated at 24 h and after thermocycling in one control group (no plasma) and in two experimental groups (pulsed plasma and conventional plasma groups) using the Scotchbond Multi‐Purpose Plus Adhesive System. Data were analyzed using two‐factor repeated‐measures anova and Weibull statistics. Fractured surfaces and the bonded interfaces were evaluated using a field‐emission scanning electron microscope. Although there were no significant differences between the plasma treatment groups, the plasma treatment improved the MTBS compared with the control group. After thermocycling, the MTBS did not decrease in the control or conventional plasma group but increased in the pulsed plasma group. Thermocycling increased the Weibull moduli of plasma‐treated groups. In conclusion, plasma treatment using NT‐APP improved the adhesion of resin composite to dentin. Using a pulsed energy source, the energy delivered to the dentin was effectively reduced without any reduction in bond strength or durability.     

牙齿漂白专用比色板的设计方法初探

目的 通过对变色牙色度值的分析,探讨通过统计学方法设计牙齿漂白专用的,可以科学、准确地评价漂白效果的比色板。方法 分析2009年2月-2014年7月就诊的Beyond冷光美白患者的136张临床照片,其中四环素牙25例,氟斑牙61例,黄牙50例,测量变色牙色度值;用系统聚类分析法确定色标L*值,根据变色牙的a*、b*均值确定色标a*、b*值,为3种变色牙分别设计漂白专用比色板,并评价其效果。结果 3种变色牙的色度值存在差异;所设计的比色板与Vitapan Classical比色板相比色标排列更有规律,对漂白效果的评价更准确、更科学,其色标与变色牙的色差值更小。结论 这种牙齿漂白专用比色板的设计方法理论上是可行的,其实际效果还有待临床检验。     

Evaluation of the bactericidal effect of cold atmospheric pressure plasma on contaminated human bone: an in vitro study

The use of cold atmospheric pressure plasma (CAPP) as a bacterial decontaminant for chronic wounds has shown good results. The purpose of this in vitro study was to evaluate the bactericidal effects of CAPP on the cancellous area of the bone. Sterile glass slides and processed sterile human bone allografts 1, 2, 3, and 4 mm thick were used for initial contamination and further CAPP treatment. Each block was contaminated with Staphylococcus aureus suspension on one side. Each slide was turned 180° and treated on the reverse side. The bacterial count in colony-forming units (CFU) was then measured and compared with that of a control group, and the bactericidal effects of CAPP in relation to bone density evaluated. A significant reduction in count was measured between treated and untreated groups (groups A-D: p < 0.01 and group E: p = 0.04). A strong positive linear relation was found between bone density and the S aureus count (r = 0.844, p = 0.156). Treatment with CAPP had a bactericidal effect on bone structures with a penetration depth of up to 4 mm. It might be used for all diseases involving infected bone, and so extends the existing range of treatments.     

Clinical trial of tooth desensitization prior to in‐office bleaching

The aim of this clinical trial was to compare tooth sensitivity during and after bleaching with hydrogen peroxide gel following application of GLUMA Desensitizer PowerGel or placebo. Forty‐six subjects with sound maxillary incisors and canines were enrolled. Tooth shades were determined by comparison with a Vitapan Classic Shade guide. GLUMA Desensitizer PowerGel and placebo were randomly applied to the labial surfaces of the left or right anterior teeth for 1 min, which were then rinsed and dried. Then, Opalescence Boost PF 40% gel was applied onto labial enamel for 15 min. Sensitivity scores [recorded on a 10‐point visual‐analog scale (VAS)] were determined before, at 5, 10, and 15 min during, and 1, 24, 48 h and 1 wk after, the bleaching treatment. Shades were determined postbleaching and after 1 wk. Prebleaching application of GLUMA Desensitizer PowerGel significantly reduced tooth sensitivity during and after bleaching when compared with treatment with placebo. The whitening effects immediately and 1 wk after bleaching were significant when compared with the prebleaching shades. In conclusion, tooth pretreatment with GLUMA Desensitizer PowerGel for 1 min prior to 15 min of in‐office bleaching with 40% hydrogen peroxide gel was highly effective in reducing tooth sensitivity during and after bleaching.     

The effect of bleaching gel and (940 nm and 980 nm) diode lasers photoactivation on intrapulpal temperature and teeth whitening efficiency

This in vitro study aimed to investigate the whitening efficacy of 940 nm and 980 nm diode laser photoactivation in tooth bleaching by analysing pulp chamber temperature, as well as the change in tooth colour. Root canals of thirty extracted human lower premolars were prepared. Laserwhite* 20 bleaching agent containing 38% of hydrogen peroxide was photoactivated with 7 W output power of 940 nm and 980 nm diode lasers for 120 s. Bleaching gel reduced 27–29% of the temperature from reaching the pulp chamber. For shade assessment, only the groups photoactivated using diode lasers showed statistically significant differences from control group P < 0.001. Within the studied parameters, both 940 nm and 980 nm diode lasers produced a safe pulp temperature increase. Diode laser photoactivation of bleaching gel resulted in more efficient teeth whitening. Photoactivation with 940 nm diode laser yielded the highest change in colour with only minor increase in pulp chamber temperature.     

Evaluation of plasma treatment effects on improving adhesive–dentin bonding by using the same tooth controls and varying cross‐sectional surface areas

The objective of this study was to evaluate and verify the effectiveness of plasma treatment for improving adhesive–dentin interfacial bonding by performing microtensile bond‐strength (μTBS) testing using the same‐tooth controls and varying cross‐sectional surface areas. Extracted unerupted human third molars were used after removal of the crowns to expose the dentin surface. One half of each dentin surface was treated with a non‐thermal argon plasma brush, whilst the other was shielded with glass slide and used as an untreated control. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were then applied as directed. The teeth thus prepared were further cut into micro‐bar specimens, with cross‐sectional sizes of 1 × 1 mm², 1 × 2 mm², and 1 × 3 mm², for μTBS testing. The test results showed that plasma‐treated specimens gave substantially stronger adhesive–dentin bonding than their corresponding same‐tooth controls. Compared with their untreated controls, plasma treatment gave statistically significant higher bonding strength for specimens with a cross‐sectional area of 1 × 1 mm² and 1 × 2 mm², with mean increases of 30.8% and 45.1%, respectively. Interface examination using optical and electron microscopy verified that plasma treatment improved the quality of the adhesive–dentin interface by reducing defects/voids and increasing the resin tag length in dentin tubules.     

Improved resin‐to‐dentin bond strength and durability via non‐thermal atmospheric pressure plasma drying of etched dentin

This study aimed to evaluate the improvement in strength and durability of the bond between dentin and composite resins following plasma drying of the etched dentin surface using non‐thermal atmospheric pressure plasma. Plasma drying was applied to the etched dentin before applying adhesive. Conventional wet‐bonding and helium (He) gas‐dried bonding schemes were used as control groups. The bond strength of the composite resin to dentin was measured as the microtensile bond strength at 24 h after bonding and after 10,000 cycles of thermocycling. Hybrid layer formation was observed using micro‐Raman spectroscopy and scanning electron microscopy. Although the bond‐strength values were not statistically different either at 24 h after bonding or after thermocycling, the bond strength of the plasma‐dried bonding group was significantly higher than the conventional wet‐bonding group and He gas‐dried bonding group. Micro‐Raman spectral analysis revealed effective penetration of the adhesive and an improved polymerization rate of the adhesive after plasma drying. Plasma drying increased the penetration of hydrophobic resin into the collagen mesh structure, which improved mechanical bonding and long‐term durability between dentin and composite resin.