无龋根面和牙骨质龋菌斑菌丛的研究

本实验选择门诊患者28人,分为无龋恨面组和牙骨质龋组进行了细菌学研究。结果提示:轻链菌、粘放菌和内氏放线菌是参与菌斑组成的基本成员;变链菌在牙骨质龋组中显著多于正常无龋根面组达10倍以上,在统计学上有极显著差异,提示变链菌为根龋的主要致病菌;而韦荣氏菌是基础牙菌斑微生物群落成员之一。     

釉质表层特征与早期釉质龋形成的关系

釉质表层是在早期龋时釉质表面相对完整的一层结构，其出现与表面釉质的晶体排列和化学组成有关，早期釉质龋不单是矿物质的溶解和丢失，还包括溶解的矿物质在釉质表层的选择性再矿化，釉质表层和再矿化在早期龋损过程中有重要作用。对釉质表层和早期釉的研究是指导早期龋预防和治疗的关键。本文就釉质表层结构特点，化学组成特点及近6年来众学者对早期龋的形成和预防方面的研究作一综述。     

人牙早期釉质龋通透性研究

人牙早期釉质龋的发生，发展机理尚有许多不明之处，早期龋釉质的通透性在龋病发生发展中的作用研究和报道甚少，本文采用扫描电镜技术、生物化学方法和细胞学方法对人牙早期釉质的通透性加以研究观察。结果发现葡萄糖和细菌能穿过早期龋釉质表层进入表层下，扫描电镜图象也证实早期龋损表层下的损害主体内有细菌生长繁殖。本文结果表明，早期龋釉质对糖和细菌具有一定通透性，这种通透性是早期龋得以进一步发展的必要条件。     

Nd：YAG激光照射釉质,牙本质和牙骨质的形态变化

应用不同能量的脉冲Ｎｄ：ＹＡＧ激光照射釉质、牙本质和牙骨质表面，用ＳＥＭ观察其形态变化。结果表明：这些组织的表面产生许多密集、形态和边缘不规则的凹窝结构，深度１５～４０μｍ不等，但３种组织表面形态的改变和程度各不相同。分析讨论了粗糙的表面对复合树脂粘结的潜在意义，并提出合适的激光能量参数     

特异性鸡蛋黄抗体对人工釉质龋形成的影响

目的：研究特异性鸡蛋黄抗体（IgY）对人工釉质龋形成的影响。方法：采用人工菌斑模型研究IgY对早期釉质龋形成的影响。56块釉质块经唾液包被后置6种与菌斑形成有关的混合细菌液中培养。实验组釉质块每两天置IgY液中浸泡处理,在实验第7、14、21、28、35天分别取出对照、实验组釉质块,磨片后偏光显微镜下观察,并采用显微X线照相系统投照,TMR软件分析早期釉质脱矿量、龋损的深度。结果：对照组较实验组更早出现釉质龋,实验组釉质脱矿量为1275．2 vol％um,显著低于对照组2836．5vol％ um。结论：特异性IgY在体外能有效减缓早期釉质龋的发生。     

釉质龋的非破坏性治疗方法

釉质龋是一种非细胞反应性病变,可导致牙齿硬组织的破坏。传统治疗釉质龋的方法往往会损害到正常的牙体组织,因此目前非破坏性修复釉质龋的新方法成为了研究的热点和难点,本文就非破坏性治疗釉质龋的2种方法——再矿化和仿生矿化法的最新进展作一综述。     

釉质龋牙髓损伤反应的观察

目的观察釉质龋阶段牙髓的组织病理学改变,并探讨牙髓损伤与龋损活动性的关系。方法选用拔出的患釉质龋的第三磨牙22颗（其中急性龋12颗,慢性龋10颗）,无龋第三磨牙10颗作为对照,脱钙、切片、常规染色。光镜下观察釉质龋损下牙髓的组织病理改变。用多功能图象分析仪测量此区内成牙本质细胞的浆核面积之比（简称浆核比）、数目及前期牙本质的面积,血管数目与横截面积,炎症细胞数目。结果慢性的釉质龋未见明显的病理改变。急性釉质龋牙髓的病理变化有：前期牙本质变窄,成牙本质细胞排列紊乱,细胞体积缩小,胞核向前期牙本质区移位;少细胞层见少量成纤维细胞与炎症细胞侵入;多细胞层可见血管轻度扩张,成纤维细胞增殖。少量炎症细胞主要为淋巴细胞和单核细胞。结论釉质龋时牙髓可以出现成牙本质细胞的损伤性变化,而这种变化与龋损活动性相关。     

釉质初期龋损组织氨基酸组成含量分析

许多学者已利用层析、凝胶电泳及氨基酸分析技术 ,发现无论在人或牛的牙釉质中 ,蛋白质的组成均以甘氨酸、脯氨酸、谷氨酸、胱氨酸、天门冬氨酸的含量最高[1] 。Ｌｉｎｄｅｎ(1985 ) [2 ] 对牛牙釉质表层下脱矿中蛋白质的丧失情况进行了研究 ,发现蛋白质在脱矿过程中丢失。丢失的氨基酸主要为甘氨酸、谷氨酸、脯氨酸、丝氨酸、天门冬氨酸 ,即以正常的牛牙釉质中所含的主要氨基酸为主。本文用氨基酸自动分析方法 ,对人釉质初期龋损组织中以及邻近的正常釉质中氨基酸组成含量进行分析 ,以探讨在人釉质初期龋形成过程中 ,釉质氨基酸的变化情况…     

釉质龋的非破坏性治疗方法

釉质龋是一种非细胞反应性病变,可导致牙齿硬组织的破坏.传统治疗釉质龋的方法往往会损害到正常的牙体组织,因此目前非破坏性修复釉质龋的新方法成为了研究的热点和难点,本文就非破坏性治疗釉质龋的2种方法——再矿化和仿生矿化法的最新进展作一综述.     

早期釉质龋表层形成的化学机制

早期釉质龋表层相对完善，表层脱矿比表层下轻是其典型的病理特征，也是龋损机制的难点和关键。本文介绍了对早期釉质龋表层形成机制的研究历程，各种学说及氟等抑龋因子在早期龋表层形成中所发挥的作用。     

Comparative study of plaque pH on enamel and cemental surfaces

This study was undertaken to compare the pH response of enamel and cemental plaques to a sucrose rinse challenge. The plaque pH readings on the enamel surfaces were consistently lower than the subjacent cemental plaque pH readings on the same teeth at the same time intervals following the sucrose exposure.     

The relationship between cemental caries, oral hygiene status and fermentable carbohydrate intake.

Two groups of patients were evaluated for the presence of active, restored, and recurrent root surface caries. One group of 120 subjects had received treatment for moderate to severe periodontitis. The second group consisted of 124 subjects who were affected by moderate to severe periodontitis but had received no treatment. The two groups were also evaluated for amounts of recession, pocket depth, and the presence of bacterial plaque. In addition, each subject was asked to compile a record of his/her dietary intake for a seven-day period. The treated group was found to brush and floss more frequently than the untreated group and had a lower mean plaque score (45.8), than the untreated group (61.4). There was no difference in the mean plaque scores for the subgroups with and without root surface caries within either the treated groups. The prevalence of root surface caries increased through age 59 in the treated group, then diminished after age 60. In the untreated group the prevalence increased steadily with age. Analysis of the data from the dietary hisories revealed that the subjects in both the treated and the untreated groups who were affected with root surface caries had a significantly higher (P less than 0.01) number of fermentable carbohydrate exposures per week.     

The predominant microflora of nursing caries lesions.

The predominant microflora recovered from infected dentine of 52 carious teeth from 14 children with nursing caries was determined using both selective and non-selective media for the isolation of specific genera and acidified media (pH 5.2) to isolate the predominant aciduric microorganisms, and compared with the microflora of sound enamel surfaces in caries-free children. Streptococcus mutans formed a significantly greater proportion of the lesion flora while Streptococcus oralis, Streptococcus sanguis and Streptococcus gordonii formed a significantly greater proportion of the plaque flora from sound tooth surfaces. The proportions of Actinomyces naeslundii and Actinomyces odontolyticus were significantly greater in the plaque samples than in the lesion samples. Actinomyces israelii formed 18.2% of the flora from the lesions, but was not isolated from the plaque samples. The proportions of Candida albicans, Lactobacillus spp. and Veillonella spp. were also significantly greater in the carious dentine than in the plaque samples. The most frequently isolated lactobacilli were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus rhamnosus. The predominant aciduric flora was S. oralis, S. mutans and A. israelii and these taxa were also isolated from a similar proportion of the lesions at pH 7.0. Strains of S. mutans, L. casei, L. fermentum and L. rhamnosus isolated from individual carious teeth were genotyped using PCR-based methods. Each species was genotypically heterogeneous and different genotypes were recovered from different carious teeth in the same child. These data indicate that the microflora of lesions in the same child is microbiologically diverse and support a non-specific aetiology for nursing caries in which the physiological characteristics of the infecting flora, not its composition, is the major determinant underlying the disease process.     

The nature of early caries lesions in enamel

Since 1935, various mechanisms have been suggested for the formation of subsurface lesions and, in particular, the surface layer covering enamel lesions. The relatively intact mineral-rich and porous surface layer is most likely caused by kinetic events. The suggested mineral-rich outer layer in sound enamel, the organic matrix, the pellicle, or a non-uniform ion distribution have all been shown to be non-essential for surface layer formation; they may, however, influence the rate of surface layer formation. Models based on outer surface protection by adsorbed agents, the dissolution-precipitation mechanism, and combinations of these two models, as well as models based on porosity or solubility gradients, are discussed in this paper together with their advantages and disadvantages. Most models have not explained some important recent experimental observations on initial in vivo caries lesion formation: e.g., initial enamel lesions formed in vivo do not have a surface layer initially but develop this mineral-rich layer later on; and the fact that the F- level in the solid sound enamel is not determining the subsurface lesion formation. Furthermore, the observations that in vitro fluoride ions in the liquid at very low levels (approximately equal to 0.02 ppm) determine surface layer formation are difficult to explain. A new kinetic model for subsurface lesion formation is described, in which inhibitors such as F- or proteins play an important role. The model predicts that if lesions depth and demineralization period are denoted by df and t, lesion progress can be described by: dfp = alpha t + c, where alpha and c are constants with 1 less than or equal to p less than or equal to 3, depending on the lesion formation conditions. If lesion progress is entirely diffusion-controlled, p = 3, corresponding to low inhibitor concentrations; if the inhibitor content is so high that the progress is controlled by processes at the crystallite surface, p = 1. A kinetic mechanism for surface layer formation in vivo is proposed, based on the assumption that F- is a main inhibitor in the plaque-covered acidic in vivo situation. The inhibiting fluoride, adsorbed onto the crystallite surfaces at OH- vacancies, originates from the so-called fluoride in the liquid phase (FL) between the enamel crystallites. Under acidic conditions (plaque), we have, due to an influx of fluoride from the saliva or plaque as FL, an aqueous phase in the enamel supersaturated with respect to the mineral for a small distance (x*) only.(ABSTRACT TRUNCATED AT 400 WORDS)