Fixation and demineralization of bone tissue for immunohistochemical staining of neuropeptides

Summary The present study in the rat demonstrates the feasibility of applying immunohistochemical staining techniques on bone tissue for studies of substances such as neuropeptides contained in nerve fibers. Two fixation procedures, as well as the influence of demineralization on neuropeptide antigenicity, were studied in bone and for comparison in small intestine.In vivo perfusion with paraformaldehyde and picric acid, followed by demineralization in a solution of either EDTA-cacodylate or buffered EDTA-sucrose, proved to be the most appropriate with respect to preserved substances were tested. In the bone tissue, immunoreactivity was found to four neuropeptides: substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, and neuropeptide Y, and also to the catecolamine-synthesizing enzyme tyrosine hydroxylase. The described method for identifying intraosseal neuropeptides offers a new means of studying skeletal innervation and bioactive substances in bone tissue.     

新型生物活性玻璃促进人工牙本质龋再矿化的作用

目的：研究以植酸为前驱体合成的生物活性玻璃(phytic acid derived bioactive CaO-P₂O₅-SiO₂ gel-glasses, PSC)和含氟生物活性玻璃(fluoride-containing bioactive glasses, FBG)这两种新型生物活性玻璃(bioactive glass, BG)对人工牙本质龋再矿化的作用,为促进牙本质龋再矿化寻找更有效的方法。方法：(1)PSC是以植酸为磷前驱体、采用溶胶凝胶法制备,其化学组成为10.8%P₂O₅-54.2%SiO₂-35.0%CaO(摩尔百分比); FBG采用熔融法制备,化学组成为6.1%P₂O₅-37.0%SiO₂-53.9%CaO-3.0%CaF₂(摩尔百分比);传统生物活性玻璃45S5采用熔融法制备,化学组成为6.0%P₂O₅-4...     

A pattern of post-traumatic demineralization of bone simulating permeative neoplastic replacement: A potential source of misinterpretation

Long bones with a prominent endosteal trabecular pattern, particularly the herringbone configuration, when immobilized, will demineralize in a striking spotty pattern which may simulate neoplastic permeative replacement of bone. The recognition of this phenomenon will obviate needless concern and investigation.     

Enamel demineralization during orthodontic treatment. Aetiology and prevention

The aetiology of enamel demineralization during fixed orthodontic treatment and its sequelae are discussed. A summary is given of the various methods available to assess the risk of demineralization prior to active treatment. The best preventive strategy would appear to be an assessment of risk factors prior to banding, coupled with fluoride rinses, regular reinforcement of oral hygiene, and dietary advice throughout the course of treatment.     

不同饮料对SD大鼠牙釉质脱矿影响的激光共聚焦扫描电镜观察

目的通过激光共聚焦扫描电镜了解饮料对釉质脱矿的影响。方法80d龄SD大鼠42只,每只单笼饲养,喂饲致龋饲料15天后检测无牙釉质脱矿。余鼠随机分为去离子水组(阴性对照,A组)、雪碧组(碳酸类,B组)、伊力纯牛奶组(牛奶类,C组)、农夫山泉矿泉水组(矿泉水类,D组)、统一鲜橙多组(果汁类,E组)和康师傅鲜c组(果汁类,F组),每组6只,喂饲饮料3个月,用激光共聚焦扫描显微镜观察磨牙釉质的脱矿情况。结果雪碧、统一鲜橙多和康师傅鲜c组的荧光面积、总荧光面积及平均荧光量分别是12.75×10-3μm2、19.83×10-3及1.56;8.90×10-3μm2、14.52×10-3及1.63;15.05×10-3μm2、24.04×10-3及1.60,明显高于对照组(P<0.05),其值为6.03×10-3μm2、9.73×10-3及1.55,其中又以康师傅鲜c组为最高。矿泉水和牛奶类的荧光面积和总荧光量都较低,分别为3.45×10-3μm2、5.41×10-3和3.87×10-3μm2、6.14×10-3,与对照组相比没有显著性差异(P>0.05),与酸性饮料(包括碳酸类和果汁类)比较有显著差异(P<0.01)。结论酸性饮料具有较强的酸蚀性,牛奶和矿泉水对釉质脱矿没有明显的影响。     

Demineralization of drinking water: Is it prudent?

Water is the elixir of life. The requirement of water for very existence of life and preservation of health has driven man to devise methods for maintaining its purity and wholesomeness. The water can get contaminated, polluted and become a potential hazard to human health. Water in its purest form devoid of natural minerals can also be the other end of spectrum where health could be adversely affected. Limited availability of fresh water and increased requirements has led to an increased usage of personal, domestic and commercial methods of purification of water. Desalination of saline water where fresh water is in limited supply has led to development of the latest technology of reverse osmosis but is it going to be safe to use such demineralized water over a long duration needs to be debated and discussed.     

The influence of different irradiation doses and desensitizer application on demineralization of human dentin

The aim of the present study was to evaluate the effect of different irradiation doses after desensitizer application on the onset of initial demineralization of human dentin in situ. The root surfaces of 45 freshly extracted caries-free human molars were cleaned, thereby removing the cementum. From each tooth two root dentin specimens were prepared. The specimens were distributed among the following experimental groups: 0, 0.5, 1, 2 and 5 Gy. The irradiation dose was fractionally applied (0.5 Gy/day). One dentin specimen of each group was inserted into both buccal aspects of nine intraoral mandibular appliances. On one side the specimens were additionally coated with the desensitizer Hyposen (H). On the other side, the specimens were left untreated (C). The appliances were worn by nine persons for five weeks day and night. During meals, the appliance was stored in 10% sucrose solution. After the in situ period, slabs (150 μm) were ground and studied using a polarized light microscope. Concerning radiation dose, significant differences were observed between the control and 5 Gy group (p < 0.05, Tukey´s test). Pairwise comparison showed that lesion depths in groups treated with Hyposen were significantly decreased. Within the limitations of this study it can be concluded that higher radiation doses seem to increase the caries susceptibility of dentin. The additional application of a desensitizer hampers the demineralization and might have a caries-protective effect on exposed irradiated root surfaces.     

保留BMP的微脱矿骨条在脊柱融合术中的应用研究

目的探讨保留BMP的微脱矿骨条在脊柱融合术中的临床疗效。方法自2005年6月~2010年12月应用保留BMP的微脱矿骨条行脊柱融合术26例﹙实验组﹚,其中颈椎8例,胸腰椎18例,术后对所有患者行切口愈合情况、异物反应及脊柱融合情况进行观察,对照组为同期应用普通同种异体骨条行脊柱后路融合术26例。结果实验组与对照组伤口均一期愈合,未发生感染。颈椎实验组、对照组均现脊柱融合;胸腰椎实验组坚强融合16例,可能融合2例,对照组坚强融合13例,可能融合5例。随访6~24月,平均15.2月,内固定系统无松动及断钉断棒。结论保留BMP的微脱矿骨条应用在脊柱融合术中,脊柱融合可,无排异、感染等并发症,临床疗效满意。     

In vitro evaluation of fluoride and calcium sodium phosphosilicate toothpastes, on root dentine caries lesions

Objectives

The aim of this in vitro study was to assess the effect of toothpastes containing three different sodium fluoride concentrations and a calcium sodium phosphosilicate system, on root dentine demineralization and remineralization.

Methods

During a fourteen-day pH-cycling protocol, pre-softened bovine root dentine specimens were immersed twice daily, before and after the demineralization periods, for 2 min, in the following toothpaste slurries: (a) non-fluoridated (control), (b) 7.5% calcium sodium phosphosilicate, (c) 1450 ppm F, (d) 2800 ppm F, and (e) 5000 ppm F. Subsequently, the slabs were subjected to a fifty-hour acid resistance test. Knoop microhardness at different lesion depths was assessed in specimen cross-sections and KHN values were converted to vol.% mineral. Comparisons between the groups were performed at each lesion depth through ANOVA-based tests and furthermore, regression analysis of the derived statistic of “integrated vol.% mineral loss” was carried out. Also, lesions were evaluated qualitatively using transmission and polarized light microscopy.

Results

The 5000 ppm F toothpaste group, during pH-cycling, presented significantly less total vol.% mineral loss and subsequently exhibited considerably increased surface acid resistance, compared to all the other tested groups. The calcium sodium phosphosilicate toothpaste, during pH-cycling, inhibited demineralization and/or promoted remineralization of the surface layers significantly more effectively than the control group nevertheless, subsequently, the acid resistance of the calcium sodium phosphosilicate dentifrice group was similar to that of the control group. These observations were confirmed by microscopic examination of the lesions.

Conclusions

Under the present experimental conditions, the 5000 ppm F toothpaste, promoted remineralization and inhibited demineralization more effectively, than the other tested toothpastes.