基于光学相干层析图像的离体牙三维重建

利用shear-warp算法对离体牙的光学相干层析图像进行三维重建,通过不透明度传递函数的合理设置及光照模型的引入实现牙齿内部组织结构的可视化,便于医生在早期龋齿诊断中定位病变.介绍了shear-warp算法的原理、用于龋齿检测的全光纤光学相干层析成像系统及其二维层析图,以及利用离体牙牙冠的二维层析图重建获得三维结构图.     

光学相干层析用于牙齿病变的检测

阐述了适用于牙齿结构成像的光学相干层析成像(OCT)系统。系统光源中心波长为1 310 nm,成像分辨率10μm,在牙内成像深度2 mm,成像速度1幅/秒,系统信噪比100 dB。利用此OCT仪清晰检测到牙齿样品的牙釉质和牙本质,观察到牙釉质与牙本质的分界面以及正常牙齿牙釉质与龋齿牙齿牙釉质OCT图像的区别。进一步设计研制了适用于口腔内探测的小型OCT探头。     

不同年龄组修复性牙本质生成情况探讨

目的观察不同年龄段人的牙齿在受到龋损刺激后,修复性牙本质的生成情况。方法收集5组不同年龄组含有牙本质浅层龋的离体牙,每组各5颗牙齿。制作标本切片,HE染色,显微镜下观察。测量修复性牙本质厚度,作统计学检验。结果5组不同年龄牙齿的修复性牙本质平均厚度分别为:3.36、2.6、2.8、4.2、3.36,统计学检验无明显差异。结论受龋损刺激后,不同年龄牙齿的修复性牙本质生成情况无明显差异。     

郑州汪沟遗址仰韶文化居民的牙齿磨耗及口腔健康状况

对汪沟遗址出土的174例仰韶文化居民的2816枚牙齿进行统计与分析,计算出牙齿的平均磨耗等级和前后部牙齿磨耗差别指数,统计特殊磨耗、龋齿、骨质隆起在样本中的出现率。结果显示,汪沟组牙齿平均磨耗等级为3.403262级,男性牙齿平均磨耗等级为3.63级,女性为3.61级;男女两性牙齿磨耗差异不显著（p>0.05);前后部牙齿磨耗差别指数比达到1:1;出现26例由于深覆牙合导致的特殊磨耗;臼齿咬合面凹坑式磨耗出现率为2.50%;龋齿患病率68.97%,龋齿率26.56%,龋均4.30;骨质隆起的出现率为5.20%,颌骨粗壮程度不显著。汪沟人群的牙齿磨耗程度总体偏轻,牙齿磨耗程度与河南下王岗组居民接近。基于以上特点,我们认为中原地区仰韶文化人群在饮食结构和用牙习惯上存在一定的共性。     

咖啡和茶可防龋齿

美国加利福尼大学牙科学院的一位口腔生物学副教授罗伦斯·伍林斯基,在研究尼日利亚人的咀嚼糖(是当地的一些植物加工而成)时,发现它可能是导致尼日利亚龋齿发病率低的原因。由于“咀嚼糖”中含有单宁能够阻止细菌附着到牙齿的珐琅质上,因而可预防龋牙。他们在实验中对这一猜想进行了验证,把“咀嚼糖”提取物加入到引起龋牙的菌系中,然后把这种菌     

郑州孙庄遗址仰韶文化人群的龋病

孙庄遗址位于河南省郑州市中原区孙庄村,是分布在黄河中游的一处仰韶文化晚期遗址,该遗址出土的54例仰韶时期的人骨保存状况良好,为我们了解仰韶文化人群的龋患情况提供了珍贵的资料。本文以肉眼观察为主并结合超景深显微镜对遗址出土的846枚牙齿进行鉴定、统计与分析,得出以下结论：孙庄遗址古代人群的龋病患病率70.37%,龋齿率22.93%,龋均3.59;壮年组患龋率最高,为88.89%,不同年龄组之间的龋齿率差异性显著;龋齿率女性为30.55%,男性为16.16%,女性龋齿率显著高于男性,P(0.000)<0.05,两性之间的龋齿率有显著差异;浅龋率为6.70%,中龋率为21.65%,深龋率为27.32%,深龋已穿髓率为19.07%,残冠残根率为25.26%,随着年龄的增长,龋病的病变程度呈加重趋势;龋损范围小于1/2牙冠累龋最常见,占总患龋齿数的42.27%;上颌龋齿率为26.91%,下颌龋齿率为19.70%,上下颌龋齿率差异显著（P<0.05）。龋病在不同牙位上的发生率依次为M3>M2>P2>M1>P1>C>I1>I2;邻面和 面是主要的龋患分布处,分别占患龋牙齿数的46.40%和39.18%。孙庄人群门齿较高的患龋率表明该遗址人群患龋情况已经非常严重,患龋率与龋齿率明显高于其他古代组,较高的龋病罹患率可能与孙庄人群复杂的农业经济模式有关。     

中国茶预防龋病的研究

收集了３９种茶叶，制成１％茶水，要用Ｆ＾－选择性电极法测定其中的Ｆ＾－，等离子发射光谱法测定其它离子成份，探讨茶中各种微量元素与Ｆ＾－之间影响和关系。本文还对三种茶在离体牛牙釉质人工龋再矿化作用和对正常牙釉面抗龋作用的影响进行了显微硬度测定。     

武汉市306名儿童牙菌斑中变形链球菌的血清型

本试验共检测了306例5～6岁学龄前儿童牙菌斑中的变形链球菌,在其中208名患龋齿病儿童的牙菌斑中分离出304株变形链球菌,用双向琼脂扩散法进行血清学鉴定,c、e、f血清型有259株,占所分离的变链菌总数的85.19%,其中c型206株占68%,e型37株占12%,f型16株占5%。在有龋组和无龋组牙菌斑中变链菌培养阳性率比较,有龋组变链菌培养阳性率明显高于无龋组(P<0.01)。本试验提示变链菌是武汉地区龋齿病的重要致病因素之一;武汉地区龋齿病的儿童中感染的变形链球菌血清型以c型为主。     

广西顶蛳山遗址人骨的龋齿病理观察

顶蛳山遗址位于广西壮族自治区南宁市邕宁区,保存了丰富的新石器时代文化遗存以及大量的古人类骨骼遗存。本文主要从龋齿研究入手,对顶蛳山二、三期文化(8-7 ka BP)中大于15岁的169个体的2737枚恒齿进行了观察。分别统计了龋齿等级和个体和牙齿患龋率以评估人群患龋情况,进而分析顶蛳山遗址人群的口腔健康状况,并探讨了食物构成、饮食行为与社会经济等。统计结果表明,顶蛳山遗址人群的个体和牙齿患龋率都较高。患龋率在两性、葬式、年龄段间都存在差异,女性患龋程度要高于男性;不同葬式之间差异也显著,随着年龄的增长患龋的比例和程度也随之加深。通过与其他8组新石器时代国内遗址人群的个体和牙齿患龋率的对比,我们看到包含顶蛳山在内的三组华南渔猎采集遗址的个体和牙齿患龋率都要高于其他遗址,农业遗址的人群要低于华南遗址的患龋率,而混合经济遗址的患龋率最低。龋齿的出现与人类饮食中的碳水化合物关系密切。据此,我们推测顶蛳山及其他两组华南遗址的高患龋与碳水化合物的摄入关系密切,但这与一般所认为的农业的出现没有联系。三组遗址都是以渔猎采集主导的社会经济形态,并且这时期农业并未传播至华南地区。因此我们的分析表明高患龋率与农业并没有必然联系,而华南地区当时人群所食用的碳水化合物可能源于当地的块茎类和含蔗糖类植物。     

山东广饶县中南世纪城墓地出土明代人骨的初步研究

本文对广饶县中南世纪城墓地出土的明代人骨进行了多方面的生物考古学研究,包括性别、年龄的分布,身高的复原以及古病理的观察。牙病方面,对龋病、牙釉质发育不全和错牙合畸形进行了观察记录,从性别、年龄、龋患程度及好发牙位等方面对该人群的龋患情况进行统计分析。研究结果表明,该人群牙齿患龋率不具备明显的性别差异,与年龄变化也无显著相关性,好发牙位多为臼齿。此外,还观察到多孔性骨肥厚、骨关节疾病等病理现象以及一处愈合较好的骨折创伤。     

Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography

An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light‐Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System.

QLF versus OCT imaging of enamel caries: a photonics assessment     

Use of 2D images of depth and integrated reflectivity to represent the severity of demineralization in cross‐polarization optical coherence tomography

Several studies have demonstrated the potential of cross‐polarization optical coherence tomography (CP‐OCT) to quantify the severity of early caries lesions (tooth decay) on tooth surfaces. The purpose of this study is to show that 2D images of the lesion depth and the integrated reflectivity can be used to accurately represent the severity of early lesions. Simulated early lesions of varying severity were produced on tooth samples using simulated lesion models. Methods were developed to convert the 3D CP‐OCT images of the samples to 2D images of the lesion depth and lesion integrated reflectivity. Calculated lesion depths from OCT were compared with lesion depths measured from histological sections examined using polarized light microscopy. The 2D images of the lesion depth and integrated reflectivity are well suited for visualization of early demineralization. (© 2013 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Oral health of the Paleoamericans of Lagoa Santa,central Brazil

The peopling, origins, and early prehistory of the Americas are topics of intense debate. However, few studies have used human remains to document and interpret patterns of health and lifestyle of Paleoamericans. This study provides the first investigation to characterize oral health in a series of early Holocene skeletal remains from Lagoa Santa, Brazil, a locality containing the remains of some of the earliest inhabitants of South America (10,000–7,000 BP). The sample is composed of 949 teeth and 1925 alveoli from an estimated 113 individuals excavated from 17 archaeological sites located in the State of Minas Gerais. We compare dental caries and abscess prevalence at Lagoa Santa to a large sample of human skeletons from the Western Hemisphere Project (WHP) database using both individual and tooth/alveolus count methods. In addition, antemortem tooth loss and tooth wear were analyzed in Lagoa Santa by sex and age. The results show that Lagoa Santa dental caries and abscess prevalence are significantly higher than observed among other hunter–gatherers included in the WHP database, except when abscess prevalence is considered by individual count. Adult females have less tooth wear coupled with higher prevalence of dental caries and antemortem tooth loss than adult males. These results point to an unexpected record of poor oral health at Lagoa Santa, especially among females. A diet based on a highly cariogenic combination of wild tubers and fruits is suggested as an explanation for the elevated rate, characterizing an early adaptation to a tropical environment in South America. Am J Phys Anthropol 154:11–26, 2014. © 2014 Wiley Periodicals, Inc.     

Dental health of elderly confederate veterans: evidence from the Texas State Cemetery

Analysis of the skeletal remains of 50 Confederate veterans provided a unique opportunity to explore the dental health of a geriatric sample. These men, who died between 1907-1932, had an average age at death of 76.7 years. Ninety percent were institutionalized at the Confederate Home for Men (Austin, TX) prior to their deaths. This elderly sample was assessed in terms of caries, antemortem tooth loss (AMTL), abscesses, and linear enamel hypoplasias. On a per tooth basis, the AMTL rate was 57.2%. Of 39 dentate men, 33 (84.6%) had dental caries, and 24.4% (121 of 496) of teeth were carious. Ten (25.0%) of the dentate men had hypoplastic teeth. At least one abscess was seen in 14 (28%) of 50 individuals. Results from this geriatric institutionalized sample are compared to contemporaneous historical samples. Disparities in dental health among these groups may be due to differences in average age at death, and these comparisons allow a better understanding of dental changes that occur with age. The sample is also compared to modern elderly samples: modern groups have higher caries rates, possibly because they retained more teeth. This finding may be due in part to diets in the United States becoming increasingly cariogenic over time. In addition, dental care has moved from the reactive practices seen in the nineteenth and early twentieth centuries (such as tooth extractions) to modern proactive solutions dedicated to preserving and restoring teeth (such as tooth brushing, fluoride treatments, and dental fillings).     

Relative contribution of caries and periodontal disease in adult tooth loss among patients reporting to the Institute of Dental Sciences,Belgaum, India

Objectives: To examine the reasons for tooth loss in an adult population. Methods: Patients who reported to the department of prosthodontics in Institute of Dental Sciences, Belgaum, located in the north‐western part of the state of Karnataka, in the southern region of India over a period of 2 months, with at least one missing tooth (excluding third molars) constituted the sample size. There were a total of 365 patients (185 females and 180 males) within the age group of 16–84 years (mean age 51.06 ± 16.47 years) who fulfilled this criterion. Socio‐demographic profile was recorded along with a clinical examination for assessing the number and pattern of tooth loss. The reasons for tooth loss were recorded according to the history reported by the patient. Results: In the present study of 365 patients, 58.9% of the patients were completely edentulous, 41% were partially dentate, of which 20.8% had lost their teeth from caries, 11% from periodontal disease and 9.3% from a combination of reasons. More females had lost their teeth because of dental caries whereas more males had lost their teeth because of periodontal disease, this being statistically significant. (χ² = 16.53, p = 0.001). Highly significant results were obtained for age and reasons for tooth loss. (χ² = 150.39, p < 0.001). Irrespective of the socio‐economic status, dental caries was the most common cause for tooth loss in partially dentate patients though it was not statistically significant (χ² = 13.62, p = 0.325). Mandibular first molars were the teeth most frequently lost due to dental caries. The maxillary left central incisor was most frequently lost due to periodontal disease, followed by the maxillary right central incisor. Conclusions: Since both dental caries and periodontal disease contributed to tooth loss at different ages, risk indicators need to be identified.     

A new approach for calibrating dental caries frequency of skeletal remains

It is a fact that researchers make use of various calibration methods for calculating and correcting dental caries frequency. The lack of standardization and accuracy of such methods has made it difficult for the researchers to draw reliable and differentiated conclusions from caries frequencies. Besides, the number of studies on how far the calculation methods reflect the "real" caries frequency is very limited. In this study, various methods for calculating caries frequency in skeletal samples are discussed and a new calculation method is proposed for estimating "real" caries frequency. The Hardwick's correction, which is one of the methods discussed in this study, is not successful in estimating "real" caries frequency as it proposes standard values for different life styles and dietary habits. The decayed and missing index is also considered inefficient as it assumes that all antemortem tooth loss is due to caries. The caries correction factor, proposed by Lukacs, achieves more successful results by considering factors other than caries in antemortem tooth loss, but because it does not differentiate between the anterior and posterior tooth groups during calculation, the results to be obtained therefrom may deviate from actual figures. In order to correct any such deviation, the caries correction factor must be applied separately for the anterior and posterior teeth groups since the resistance of each group to cariogenic factors is different. All the methods outlined above do not consider the effects of postmortem tooth loss on caries frequency. As a result, these methods are still far from reflecting a reliable caries frequency. The application of a proportional correction factor--as a technique newly introduced here--corrects the deviation caused by postmortem tooth loss and achieves more realistic results.     

An effect of zinc deficiency on dental caries.

Rat pups suckled by dams fed a zinc-deficient diet developed higher levels of dental caries following a caries-test challenge than pups suckled by dams fed a zinc-adequate diet. The zinc deficient treatment was administered during the mineralization stage of tooth development before the molars erupted. The data shows that suboptimal zinc nutriture was associated with an increase in dental caries.Fluoride, a trace element, is recognized as a factor in preventing dental caries and its use has had a significant impact on dental health in this country. However, the possible roles of other trace elements have not been closely examined. Zinc is a trace element important to bone mineralization as well as in general nutrition.The effects on dental caries produced by the addition of zinc to rat diets have been reported (1, 2, 3). In those investigations, however, zinc supplements were added to diets that were adequate in zinc. Moreover, zinc supplements were fed after the teeth had appeared in the oral cavity. Because the critical period of tooth maturation occurs before eruption (4), post-eruptive zinc supplements probably should not markedly influence the development and, specifically, the mineralization of the tooth. Therefore, we investigated the influence of pre-eruptive zinc deficiency on caries development in rats.