Er-YAG激光在牙体硬组织中的应用

随着科学技术的进步,激光技术正以惊人的速度向前发展。激光具有许多优异的性能,已被应用到人类生活的各个领域。伴随激光医学的进展,近来在口腔医学方面的研究已逐步开展起来,除了应用于口腔软组织处理外,激光用于牙体硬组织也得到了越来越多的关注。其中Er-YAG激光在口腔领域的实用性和安全性已得到多方面的认证。该文就激光在口腔医学特别是牙体硬组织中的应用作一综述。     

Er-YAG激光在口腔软组织中的应用

随着科学技术的进步,激光技术正以惊人的速度向前发展。自激光引入口腔治疗中以来,被广泛的应用于口腔硬组织中。由于激光杀菌、消毒等特性研究的广泛报道,近来激光应用于口腔软组织也得到了越来越多的关注。其中Er-YAG激光在口腔领域的实用性和安全性已得到多方面的认证。该文就激光在口腔医学特别是软组织中的应用作一综述。     

放射数字化减影技术（Digital Subtraction Radiography）在评估骨组织细微变化方面的应用

在口腔医学临床实践中,对及时发现早期、细微硬组织的变化提出了越来越高的要求。由于口腔颌面部硬组织结构复杂,运用常规的影像学检测手段常难以对早期病损作出准确的诊断。即使已存在明显的牙槽骨丧失,但确诊变化程度,常受种种因素干扰而发生误差。在口腔种植中,早期存在的种植体周     

Er,Cr:YSGG激光在口腔医疗中的应用研究进展

Er,Cr:YSGG激光是新一代水动力生物激光系统,其特性和优势正在口腔医疗的应用中越来越受到关注,该文对Er,Cr:YSGG激光对于牙体组织的去龋能力、清除玷污层和蚀刻作用以及对于牙周病变牙根表面的杀菌、去除菌斑和牙石的能力等方面的研究进展进行综述。     

Er:YAG激光脉宽对牙硬组织消融特性影响的研究

研究了Er:YAG激光消融离体牙本质过程中激光脉宽对消融阈值、消融深度以及消融后牙硬组织微结构的影响。使用50μs到1 ms脉宽的Er:YAG激光对人牙本质在无喷水冷却下消融实验,通过体式光学显微镜观察样品消融切口进而测量消融坑洞深度,利用扫描电镜(SEM)观察消融后牙本质的形态。实验结果表明,随着激光脉宽的增加,Er:YAG激光对人牙本质的消融阈值、消融深度呈现逐渐增大的趋势,同时还观察到高能量密度消融实验中牙小管封闭以及牙本质熔融现象。该实验结果对了解Er:YAG激光消融牙硬组织的微观过程及牙科治疗应用具有参考价值。     

PBL教学法在口腔临床带教中的运用体会

目的探讨PBL教学法在口腔牙体牙髓科临床实习带教中的实施效果。方法将2014年1~4月在我科实习的2009级口腔医学专业本科实习生34名随机分成观察组和对照组。对照组采用LBL教学模式,即传统的讲授式教学法;观察组采用PBL教学模式,即基于问题的学习教学法。观察比较两组学生病例分析能力、医患沟通能力和出科考试成绩。结果观察组在病例分析能力、医患沟通能力和出科考试成绩方面均明显优于对照组。结论 PBL教学法在口腔牙体牙髓科的临床实习带教效果显著,学生的临床综合素质得到明显提高。     

XeCl准分子激光消融几种生物组织的实验结果

本文报道了３０８ｎｍＸｅＣｌ准分子激光对人牙硬组织和猪肉软组织消融的实验研究结果,在国内首次开展了ＸｅＣｌ准分子激光牙科应用的基础研究,为准分子激光在牙科的临床应用提供了实验依据。     

牙齿生长线——解人类演化及生活历史的新方法

绝大多数哺乳动物的牙齿分为门齿、犬齿、前臼齿和臼齿。从外部观察,牙体由牙冠、牙根及牙颈三部分组成,从牙体的纵剖面可见牙体由牙釉质、牙本质、牙髓和牙根组成。在牙齿表面和内部保留着周期性的发育记录称为牙齿生长线,代表牙齿硬组织分泌的时间间隔,     

排龈线在楔状缺损充填修复中的应用体会

楔状缺损为临床常见牙体病,多采用光固化树脂或玻璃离子体水门汀充填修复。楔状缺损为位于唇颊侧牙颈部的硬组织缺损,缺损部位多可达龈缘以下。充填修复的质量对牙及牙周的健康有重要的影响。近两年来我科应用排龈线在楔状缺损充填前进行排龈,使缺损部位充分暴露,充填效果满意。     

脉冲CO2激光骨组织消融和电钻磨削的弹坑形态比较

激光消融技术在生物骨硬组织领域具有广泛的应用前景.选用脉冲CO2激光对离体牛胫骨组织进行消融,以电钻作为参照组,体视显微镜和扫描电子显微镜观察骨组织弹坑的形态学变化,光学相干层析成像(OCT)技术测量弹坑消融深度.比较结果表明:脉冲CO2激光辐照骨硬组织后产生的消融凹陷在几何形状和形态学方面与电钻的磨削效果相类似.此外,喷水速率为31 mL/min时可减少热损伤,并提高消融效率.     

外胚间充质干细胞在牙组织工程的应用与基因调控

用干细胞构建组织工程化牙齿是近年来口腔医学领域的研究热点,外胚间充质干细胞是目前已知牙源性干细胞的共同前体细胞,细胞的生物学特性和成牙信号分子环境是牙齿发育与再生的核心与关键,并贯穿于牙齿形成的全过程,是研究牙组织工程最具潜力的种子细胞,明确外胚间充质干细胞成牙分化能力及相关表型特征和分化特性,对进一步深入认识牙齿发育与再生机理具有重要作用。     

Histological Observations of Dental Tissues Using the Confocal Laser Scanning Microscope

To investigate the time course of mineralization in undecalcified dental tissues, calcein-and tetracycline-labeled rat maxillary molar sections were stained with Villanueva bone stain en bloc, embedded in methyl-methacrylate (MMA), ground to 50 μm thickness, and observed by confocal laser scanning microscopy (CLSM). This method allowed observation of dental structures including odontoblasts, pulp cells and periodontal ligament, and dentinal tubules and enamel rods at high resolution; labeled enamel, dentine, and cementum could be observed simultaneously regardless of section thickness. CLSM permitted simultaneous observation of both the components of calcified tissue and the cellular components of dental tissues, and assessment of the mineralization time course of hard tissues labeled by tetracycline or calcein. The technique is useful for both assessing the elements composing dental structure and observing the histological dynamics by which dental structure develops.     

Histological Observations of Dental Tissues Using the Confocal Laser Scanning Microscope

To investigate the time course of mineralization in undecalcified dental tissues, calcein-and tetracycline-labeled rat maxillary molar sections were stained with Villanueva bone stain en bloc, embedded in methyl-methacrylate (MMA), ground to 50 μm thickness, and observed by confocal laser scanning microscopy (CLSM). This method allowed observation of dental structures including odontoblasts, pulp cells and periodontal ligament, and dentinal tubules and enamel rods at high resolution; labeled enamel, dentine, and cementum could be observed simultaneously regardless of section thickness. CLSM permitted simultaneous observation of both the components of calcified tissue and the cellular components of dental tissues, and assessment of the mineralization time course of hard tissues labeled by tetracycline or calcein. The technique is useful for both assessing the elements composing dental structure and observing the histological dynamics by which dental structure develops.     

Prospect for feedback guided surgery with ultra-short pulsed laser light

The controlled cutting of tissue with laser light is a natural technology to combine with automated stereotaxic surgery. A central challenge is to cut hard tissue, such as bone, without inducing damage to juxtaposed soft tissue, such as nerve and dura. We review past work that demonstrates the feasibility of such control through the use of ultrafast laser light to both cut and generate optical feedback signals via second harmonic generation and laser induced plasma spectra.     

Differentiation and regenerative capacities of human odontoma-derived mesenchymal cells

Regenerating human tooth ex vivo and biological repair of dental caries are hampered by non-viable odontogenic stem cells that can regenerate different tooth components. Odontoma is a developmental dental anomaly that may contain putative post-natal stem cells with the ability to differentiate and regenerate in vivo new dental structures that may include enamel, dentin, cementum and pulp tissues. We evaluated odontoma tissues from 14 patients and further isolated and characterized human odontoma-derived mesenchymal cells (HODCs) with neural stem cell and hard tissue regenerative properties from a group of complex odontoma tissues from 1 of 14 patients. Complex odontoma was more common (9 of 14) than compound type and females (9 of 14) were more affected than males in our set of patients. HODCs were highly proliferative like dental pulp stem cells (DPSCs) but demonstrated stronger neural immunophenotype than both DPSCs and mandible bone marrow stromal cells (BMSCs) by expressing higher levels of nestin, Sox 2 and βIII-tubulin. When transplanted with hydroxyapatite/tricalcium phosphate into immunocompromised mice, HODCs differentiated and regenerated calcified hard tissues in vivo that were morphologically and quantitatively comparable to those generated by DPSCs and BMSCs. When transplanted with polycaprolactone (biodegradable carrier), HODCs differentiated to form new predentin on the surface of a dentin platform. Newly formed predentin contained numerous distinct dentinal tubules and an apparent dentin–pulp arrangement. HODCs represent unique odontogenic progenitors that readily commit to formation of dental hard tissues.     

Time-gated in vivo autofluorescence imaging of dental caries.

Laser-induced time-resolved autofluorescence from carious lesions of human teeth was studied by means of ultrashort pulsed laser systems, time-correlated single photon counting and time-gated imaging. Carious regions exhibited a slower fluorescence decay with a main 17 ns fluorescence lifetime than healthy hard dental tissue. The long-lived fluorophore present in carious lesions only emits in the red spectral region. Fluorescence decay time and spectral characteristics are typical of fluorescent metal-free porphyrin monomers. The spatial distribution of the long-lived endogenous porphyrin fluorophore within the tooth material was detected by time-gated nanosecond autofluorescence imaging. In particular, high contrast video images were obtained with an appropriate time delay of 15 ns to 25 ns between excitation and detection due to the suppression of short-lived autofluorescence of healthy tissue. First in vivo applications are reported indicating the potential of time-resolved fluorescence diagnostics for early caries- and dental plaque detection.     

A numerical model for temperature distribution and thermal damage calculations in teeth exposed to a CO2 laser

A numerical axisymmetrical model which may be used for the evaluation of laser dental treatments is presented. This model facilitates the calculations of the temperature distribution and of thermal damage to pulp tissue caused by CO₂ laser irradiation. Temperature distributions are compared with analytical, experimental, and numerical results presented in the literature. The conformity obtained is good. It is shown that this model can be used over a wider range of time intervals and physical conditions than a previous numerical model. In addition, thermal damage is calculated for the temperature distributions presented in this paper. This model can be utilized for the optimization of exposure parameters to minimize pulp damage in the application of lasers for dental treatment.