BACKGROUND & AIMS: :A biobank is an organized collection of biological human material and its associated information stored for research according to regulations under institutional responsibility, without commercial purposes, being a mandatory and strategical activity for research, regenerative medicine, and innovation. Stem cells have largely been employed in research and frequently stored in biobanks, which have been used as an essential source of biological materials. Stem cells of human exfoliated deciduous teeth (SHED) are stem cells which have a high multipotency and can be easily obtained. Besides, this extremely accessible tissue has advantages with respect to storage, as the SHED obtained in childhood can be used in later life, which implies the necessity for the creation and regulation of biobanks. The proper planning for the creation of a biobank includes knowledge of the material types to be stored, requirements regarding handling and storage conditions, storage time, and room for the number of samples. Thus, this study aimed to establish an overview of the development of a SHED biobank. Ethical and legal standardization, current applications, specific orientations, and challenges for the implementation of a SHED biobank were discussed. Through this overview, we hope to encourage further studies to use SHED biobanks.

背景与目标： : 生物库是根据机构责任下的法规为研究而存储的生物人类材料及其相关信息的有组织的集合，没有商业目的，是研究，再生医学和创新的强制性和战略性活动。干细胞已广泛用于研究，并经常存储在生物库中，这些生物库已被用作生物材料的重要来源。人脱落的乳牙 (SHED) 的干细胞是具有高多能性且易于获得的干细胞。此外，这种极易接近的组织在存储方面具有优势，因为在童年时期获得的棚子可以在以后的生活中使用，这意味着创建和调节生物库的必要性。创建生物库的适当计划包括要存储的材料类型的知识，有关处理和存储条件的要求，存储时间以及样品数量的空间。因此，本研究旨在概述棚屋生物库的发展。讨论了道德和法律标准化，当前的应用，特定的方向以及实施棚屋生物库的挑战。通过此概述，我们希望鼓励进一步的研究使用棚子生物银行。

BACKGROUND & AIMS: PURPOSE:The purpose of this retrospective study was to explore clinical outcomes for NuSmile anterior preveneered stainless steel crowns. METHODS:A convenience sample of healthy children treated with anterior crowns was selected from a teaching clinic and private office. Crowns were placed by either a private practice dentist or pediatric dental resident. Clearly defined clinical outcomes were assessed by 3 calibrated examiners at recall, including: (1) presence; (2) chipping; (3) wear; (4) crazing; and (5) marginal location by clinical and radiographic examination. Factors affecting placement--such as operator experience and behavior--were also assessed. RESULTS:In 46 subjects (21 females, 25 males; mean age at placement=4 years, 2 months), 226 crowns with a mean post-placement time of 12.9 months were evaluated. Only 2 crowns matched natural teeth, with NuSmile crowns lighter in 83% of subjects. Most crowns (86%) were normal in size. Eighty-eight percent resisted fracture for 6 months. All but 3 crowns resisted color change for 6 months. Canine crowns were the least successful, but overall 91% of crowns retained good to excellent clinical appearance. CONCLUSIONS:NuSmile anterior preveneered crowns are a clinically successful restoration for primary incisors with early childhood caries.

背景与目标：

BACKGROUND & AIMS: :This reaction time study assessed the valence and strength of evaluations of people with differing levels of fluorosed teeth. Eighty participants rated photographs of smiling faces with four levels of digitally manipulated fluorosed teeth. Faces were presented on a computer screen for a period of 2000 ms followed by a single word descriptor. Participants quickly indicated whether the descriptor applied to the preceding face using a response key. Descriptors included health, aesthetic, and personal judgments. Logistic and linear regressions revealed that participants were significantly more likely to make negative judgments involving health, aesthetic, and person attributions about faces with high levels of fluorosis, and to make negative judgments more quickly and positive judgments more slowly than those with lower levels of fluorosis. These data are consistent with the view that people use negative, easily accessible, stereotypes of individuals presenting with health problems.

背景与目标： : 这项反应时间研究评估了含氟牙齿水平不同的人的评估价和强度。80名参与者对带有四个级别的数字处理的含氟牙齿的笑脸照片进行了评分。面部在计算机屏幕上显示一段时间，2000年ms，然后是单个单词描述符。参与者使用响应键快速指示描述符是否应用于前面的人脸。描述符包括健康、审美和个人判断。逻辑回归和线性回归显示，与氟中毒水平较低的人相比，参与者更容易做出涉及健康，审美和人归因的负面判断，并且做出负面判断的速度更快，正面判断的速度更慢。这些数据与人们对存在健康问题的个人使用负面的，容易获得的刻板印象相一致。

BACKGROUND & AIMS: Background/objective:The aim of this study was to evaluate force levels exerted by levelling arch wires with labial and lingual conventional and self-ligating brackets. Materials/methods:The tested orthodontic brackets were of the 0.022-in slot size for labial and 0.018-in for lingual brackets and were as follows: 1. Labial brackets: (i) conventional bracket (GAC-Twin, Dentsply), (ii) passive self-ligating (SL) brackets (Damon-Q®, ORMCO; Ortho classic H4™, Orthoclassic; FLI®SL, Rocky Mountain Orthodontics) and (iii) active SL brackets (GAC In-Ovation®C, DENTSPLY and SPEED™, Strite). 2. Lingual brackets: (i) conventional brackets (Incognito, 3M and Joy™, Adenta); (ii) passive SL bracket (GAC In-Ovation®LM™, Dentsply and (iii) active SL bracket (Evolution SLT, Adenta). Thermalloy-NiTi 0.013-in and 0.014-in arch wires (Rocky Mountain Orthodontics) were used with all brackets. The simulated malocclusion represented a maxillary central incisor displaced 2 mm gingivally (x-axis) and 2 mm labially (z-axis). Results:Lingual bracket systems showed higher force levels (2.4 ± 0.2 to 3.8 ± 0.2 N) compared to labial bracket systems (from 1.1 ± 0.1 to 2.2 ± 0.4 N). However, the differences between SL and conventional bracket systems were minor and not consistent (labial brackets: 1.2 ± 0.1 N for the GAC Twin and 1.1 ± 0.1 to 1.6 ± 0.1 N for the SL brackets with 0.013-in thermalloy; lingual brackets: 2.5 ± 0.2 to 3.5 ± 0.1 N for the conventional and 2.7 ± 0.3 to 3.4 ± 0.1 N for the SL brackets with 0.013-in Thermalloy). Limitations:This is an in vitro study with different slot sizes in the labial and lingual bracket systems, results should be interpreted with caution. Conclusions/implications:Lingual bracket systems showed higher forces compared to labial bracket systems that might be of clinical concern. We recommend highly flexible nickel titanium arch wires lower than 0.013-in for the initial levelling and alignment especially with lingual appliances.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:The aim of this retrospective investigation was to evaluate the incidence of loss to pulp sensibility testing (PST) of maxillary front teeth after paramedian (3 to 5 mm away from the suture) orthodontic mini-implant (OMI) insertion in the anterior palate. METHODS:A total of 284 patients (102 males, 182 females; mean age was 14.4 years (±8.8) years at time of OMI-Insertion) with a total of 568 OMIs (1.7 mm diameter, length 8 mm) were retrospectively investigated. A binomial regression analysis was performed to explore covariates, such as age, gender, inclination of upper central incisors, dentition status and insertion position of OMIs that could have contributed to loss of sensibility. Statistical significance was set at p < 0.05. RESULTS:Loss of response to PST was encountered during retention in 3 out of 284 patients and the respective OMIs had been placed at height of the second rugae (R-2). Affected teeth were a right canine, a left lateral and a left central incisor. Subsequent root canal treatment was successful. Results of the binomial regression analysis revealed that the covariate insertion position (R-2) of OMIs (p = 0.008) had statistically significant influence on loss of response to PST. CONCLUSIONS:(1) Although there was no radiographic evidence for direct root injury, the proximity of the implants to the anterior teeth was nevertheless statistically related to loss of PST. (2) In all cases of PST loss OMIs were inserted at the second rugae. Therefore OMIs should be placed either more posteriorly, at the third rugae or in the median plane. (3). Loss of PST was not increased for patients with palatal OMI (0.18%) compared to samples without OMI (0.25%).

背景与目标：

BACKGROUND & AIMS: :It was the aim of this study to investigate the distribution of Ca, P and C in predentin, dentin and enamel in human tooth buds and permanent teeth by EDX element analysis. The mandible of a 16-week-old human fetus containing eight mineralizing tooth buds and three human permanent molars were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80 microm thickness of the mandible were cut in the frontal-dorsal direction, and polarized light micrographs were taken of these sections. The permanent teeth were cut in mesio-distal direction. The sections were investigated with scanning electron microscopy and EDX element analysis with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, mature dentin, mineralizing enamel and young enamel of developing teeth and mature enamel of permanent teeth. In developing teeth the Ca and P content increased rapidly from outer predentin towards mineralizing dentin. In enamel prisms of developing teeth the Ca and P content increased linearly from the surface towards the enamel-dentin junction. In permanent teeth only a small layer of predentin was found. The Ca and P content in enamel and circumpulpal dentin of permanent teeth was higher than in developing teeth. The Ca/P ratio differed between predentin and dentin areas reflecting different calcium phosphate compositions, but it was the same in mineralizing and young enamel. The differences in the distribution of Ca and P reflect different mineralizing patterns of the enamel and dentin matrices.

背景与目标： : 本研究的目的是通过EDX元素分析研究Ca，P和C在人牙芽和恒牙中预牙本质，牙本质和牙釉质中的分布。将16周大的人类胎儿的下颌骨固定在甲醛中，并嵌入Technovit 9100中。沿额背方向切割下颌骨80微米厚的连续切片，并对这些切片进行偏振光显微照片。恒牙沿近中远侧方向切割。用扫描电子显微镜和EDX元素分析对切片进行了研究，并使用Philips XL 30 FEG扫描显微镜和EDAX能量色散x射线系统进行了斑点测量，EDX线扫描和元素映射。对预牙本质，与预牙本质相邻的矿化牙本质，成熟牙本质，正在发育的牙齿的矿化牙釉质和年轻牙釉质以及恒牙的成熟牙釉质进行了定量测量。在发育中的牙齿中，Ca和P含量从外部牙本质向矿化牙本质迅速增加。在发育中的牙齿的牙釉质棱柱中，Ca和P含量从表面到牙釉质-牙本质交界处线性增加。在恒牙中，仅发现一小层predentin。恒牙牙釉质和牙周牙本质中的Ca和P含量高于发育中的牙齿。钙/磷比在牙本质和牙本质区域之间有所不同，反映了不同的磷酸钙成分，但在矿化和年轻牙釉质中是相同的。Ca和P分布的差异反映了牙釉质和牙本质基质的不同矿化模式。

BACKGROUND & AIMS: BACKGROUND:Diabetes mellitus (DM) may affect the healing and survival of root filled teeth with periapical lesions. AIM:To systematically analyse the available clinical literature to evaluate the association between DM and the prevalence of radiolucent periapical lesions in root filled teeth. The review question was 'Is there a difference between the root canal treatment healing outcome (in terms of presence or absence of radiolucent periapical lesions) in diabetic and non-diabetic patients?'. DATA SOURCES:A systematic review of cross-sectional studies and prospective clinical trials was conducted according to the PRISMA checklist. The review involved a search of the electronic databases of PubMed, Scopus and EBSCO host. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS:The research protocol was previously registered in the International Prospective Register of Ongoing Systematic Reviews (CRD42019130954) and included defined inclusion/exclusion criteria. The included studies were related to the root canal treatment outcome in diabetic patients in terms of periapical radiolucent lesions associated with root filled teeth. STUDY APPRAISAL AND SYNTHESIS:The selected studies were critically analysed by two evaluators using the Joanna Briggs Institute Critical Appraisal tool. The pooled odds ratio (OR) was recognized as the primary outcome variable and measure of the effect for the occurrence of periapical lesions associated with root filled teeth of control and diabetic patients. The random-effects Mantel-Haenszel method was used, at a 95% confidence interval, to calculate the pooled OR. A funnel plot was created to evaluate possible sources of heterogeneity. RESULTS:Ten studies published between 1989 and March 2019 were selected after thorough analysis and exclusion according to the strict criteria. Seven cross-sectional studies, 1 longitudinal and 2 prospective clinical studies were included. The pooled OR was calculated by comparing 773 diabetic subjects and 1133 control subjects. The pooled OR for the observational studies and clinical studies were 1.42 and 6.36, respectively. This value signified a high prevalence of periapical lesions in root filled teeth in diabetic subjects. LIMITATIONS:There are limited prospective clinical trials on this topic. The majority of the included studies are observational. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS:The data suggest a strong connection between the presence of periapical radiolucency on root filled teeth amongst diabetics as determined by the pooled OR.

背景与目标：

BACKGROUND & AIMS: :It is known that iron is deposited in the enameloid of some teleost fishes, although its biological significance has not been clarified. In the present investigation, a quantitative analysis of iron in the enameloid of fishes of a primitive suborder, the Balistoidei, and an advanced suborder, the Tetra-odontoidei, of the Tetra-odontiformes of marine teleosts was performed by means of the electron microprobe. The results indicated that the enameloid of Balistoidei contained from 0.4-13.5% iron at its surface layer, whereas that of Tetra-odontoidei was very low in iron, which could not be discriminated from the background value of the emission intensity. The enameloid of three perciform species belonging to the Acanthuridae--from which the Tetra-odontiformes are considered to have been derived--also contained high iron (2.7-3.9%) throughout its entire layer. The iron concentration in the enameloid seemed to be related to the phylogeny of fishes rather than to their environmental water and feeding habits, and it is believed that the mechanisms of iron concentration into the developing enameloid have been lost during evolution from the Achanthuridae to the Tetra-odontoidei. Since a similar phenomenon has been previously observed with respect to the fluoride concentration in the enameloid of the same fishes (Suga et al., 1981a), it is speculated that the concentrations of iron and fluoride, which have originally no chemical correlation, have some special biological significance, although the timing and distribution pattern of their deposition are completely different.

背景与目标： : 尽管尚未阐明其生物学意义，但已知铁沉积在某些硬骨鱼类的搪膜中。在本研究中，通过电子探针对海洋硬骨鱼的原始亚目的Balistoidei和高级亚目的四齿类鱼类的enameloid中的铁进行了定量分析。结果表明，Balistoidei的enameloid在其表面层含有0.4 13.5% 的铁，而四齿突的enameloid的铁含量非常低，无法与发射强度的背景值区分开来。属于Acanthuridae的三种perciform物种的enameloid (被认为是从其衍生出的四齿龙形目) 在整个层中也含有高铁 (2.7-3.9%)。enameloid中的铁浓度似乎与鱼类的系统发育有关，而不是与它们的环境水和摄食习惯有关，并且据信，在从Achanthuridae到四齿齿突的进化过程中，铁浓度进入发育中的enameloid的机制已经丧失。由于先前已经观察到关于相同鱼类的enameloid中的氟化物浓度的类似现象 (Suga等人，1981a)，因此推测最初没有化学相关性的铁和氟化物的浓度具有某些特殊的生物学意义，尽管它们沉积的时间和分布模式完全不同。

BACKGROUND & AIMS: -2

背景与目标： -2

BACKGROUND & AIMS: OBJECTIVE:The purpose of the present work was to examine some properties of different brands of beer manufactured in Brazil that may be important to oral health. METHODS:Samples from seven different beer brands were analyzed for pH, titratable acidity, calcium and phosphate concentrations. Demineralization experiments were carried out by incubating samples with crown tooth particles (40-80 mesh) at 37 degrees C under agitation (100 strokes/min). RESULTS:The pH was lower than 4.0 for three of the seven samples and higher than 4.0 for the others. The amount of titratable acidity, expressed as the volume of 0.1N NaOH solution consumed to raise the initial pH to 7.0, and the concentrations of calcium and phosphate varied. Calcium concentration ranged from 0.21 to 1.59 micromol/ml, while phosphate concentration varied from 0.048 to 0.094 micromol/ml. Calcium released to the incubation medium was proportional to the time of incubation up to 5min. Maltose, a disaccharide, was detected in all samples studied. CONCLUSION:Differences in the properties examined indicated that some brands of beer studied may have potential dental effects.

背景与目标：

BACKGROUND & AIMS: :This clinical trial assessed the ability of Gluma Dentin Bond to inhibit dentinal sensitivity in teeth prepared to receive complete cast restorations. Twenty patients provided 76 teeth for the study. Following tooth preparation, dentinal surfaces were coated with either sterile water (control) or two 30-second applications of Gluma Dentin Bond (test) on either intact or removed smear layers. Patients were recalled after 14 days for a test of sensitivity of the prepared dentin to compressed air, osmotic stimulus (saturated CaCl2 solution), and tactile stimulation via a scratch test under controlled loads. A significantly lower number of teeth responded to the test stimuli for both Gluma groups when compared to the controls (P less than .01). No difference was noted between teeth with smear layers intact or removed prior to treatment with Gluma.

背景与目标： : 这项临床试验评估了Gluma牙本质键抑制准备接受完整石膏修复的牙齿牙本质敏感性的能力。20名患者为研究提供了76颗牙齿。牙齿准备后，在无菌水 (对照) 或在完整或去除的涂片层上两次30秒的Gluma牙本质粘合 (测试) 涂覆牙本质表面。14天后，患者被召回，以测试制备的牙本质对压缩空气的敏感性，渗透刺激 (饱和CaCl2溶液) 以及在受控负荷下通过刮擦测试进行触觉刺激。与对照组相比，两个Gluma组对测试刺激的反应明显减少 (P小于.01)。涂片层完整或在用Gluma治疗之前已去除的牙齿之间没有差异。

BACKGROUND & AIMS: INTRODUCTION:Parent/caregivers' inability to recognize the importance of baby teeth has been associated with inadequate self-management of children's oral health (i.e. lower likelihood of preventive dental visits) which may result in dental caries and the need for more expensive caries-related restorative treatment under general anesthesia. Health behavior theories aid researchers in understanding the impact and effectiveness of interventions on changing health behaviors and health outcomes. One example is the Common-Sense Model of Self-Regulation (CSM) which focuses on understanding an individual's illness perception (i.e. illness and treatment representations), and subsequently has been used to develop behavioral interventions to change inaccurate perceptions and describe the processes involved in behavior change. METHODS:We present two examples of randomized clinical trials that are currently testing oral health behavioral interventions to change parental illness perception and increase dental utilization for young children disproportionately impacted by dental caries in elementary schools and pediatric primary care settings. Additionally, we compared empiric data regarding parent/caregiver perception of the chronic nature of dental caries (captured by the illness perception questionnaire revised for dental: IPQ-RD constructs: identity, consequences, control, timeline, illness coherence, emotional representations) between parent/caregivers who did and did not believe baby teeth were important. RESULTS:Caregivers who believed that baby teeth don't matter had significantly (P<0.05) less accurate perception in the majority of the IPQ-RD constructs (except timeline construct) compared to caregivers who believed baby teeth do matter. CONCLUSION:These findings support our CSM-based behavioral interventions to modify caregiver caries perception, and improve dental utilization for young children.

背景与目标：

BACKGROUND & AIMS: :Nerve growth factor (NGF) is a key regulator of the development and differentiation of neuronal and non-neuronal cells. In the present study we examined the distribution of NGF and its low and high-affinity receptors, p75NTR and TrkA respectively, in permanent human teeth under normal and pathological conditions. In intact functional teeth, NGF, p75NTR and TrkA are weakly expressed in dental pulp fibroblasts and odontoblasts that are responsible for dentine formation, while the NGF and p75NTR molecules are strongly expressed in nerve fibres innervating the dental pulp. In carious and injured teeth NGF and TrkA expression is upregulated in a selective manner in odontoblasts surrounding the injury sites, indicating a link between NGF signalling and dental tissue repair events. Accordingly, NGF and TrkA expression is strongly upregulated in cultured primary human dental mesenchymal cells during their differentiation into odontoblasts. Targeted release of NGF in cultured human tooth slices induced extensive axonal growth and migration of Schwann cells towards the NGF administration site. These results show that NGF signalling is strongly linked to pathological and regenerative processes in human teeth and suggest a potential role for this neurotrophic molecule in pulp regeneration.

背景与目标： 神经生长因子 (NGF) 是神经元和非神经元细胞发育和分化的关键调节剂。在本研究中，我们检查了NGF及其低亲和力和高亲和力受体p75NTR和TrkA在正常和病理条件下的分布。在完整的功能性牙齿中，NGF，p75NTR和TrkA在负责牙本质形成的牙髓成纤维细胞和成牙本质细胞中弱表达，而NGF和p75NTR分子在支配牙髓的神经纤维中强烈表达。在龋齿和受伤的牙齿中，NGF和TrkA的表达在损伤部位周围的成牙本质细胞中以选择性方式上调，表明NGF信号传导与牙齿组织修复事件之间存在联系。因此，在培养的原代人类牙间充质细胞分化为成牙本质细胞的过程中，NGF和TrkA表达强烈上调。在培养的人牙齿切片中靶向释放NGF可诱导雪旺细胞广泛的轴突生长，并向NGF给药部位迁移。这些结果表明，NGF信号与人类牙齿的病理和再生过程密切相关，并暗示了这种神经营养分子在牙髓再生中的潜在作用。

BACKGROUND & AIMS: Digital imaging fiber-optic transillumination (DI-FOTI) is a novel method to detect and monitor dental caries, using light, a charge-coupled device (CCD) camera, and computer-controlled image acquisition. The advantages of DIFOTI over radiography includeno ionizing radiation, no film, real-time diagnosis, and higher sensitivity in detection of early lesions not apparent to X-ray, as demonstrated in vitro. Here, we present a method of processing DIFOTI images, acquired at different times, for monitoring changes. Of central importance to this application is pattern matching of image frames that is invariant to translation and rotation of a tooth, relative to the field of view of the imaging camera, and that is robust to changes in illumination source intensity.

Our method employs:1) wavelet modulus maxima representations for segmentation of teeth images; 2) first and second moments of gray level representations of DIFOTI images in the spatial domain, to estimate tooth location and orientation; and 3) multiresolution wavelet magnitude representations for quantitative monitoring. Even with illumination source intensity variation, it is demonstrated in vitro that such wavelet representations can facilitate detection of simulated clinical changes in light transmission that cannot be detected in the spatial domain.

背景与目标： 数字成像光纤透光 (DI-FOTI) 是一种使用光，电荷耦合器件 (CCD) 相机和计算机控制的图像采集来检测和监视龋齿的新颖方法。DIFOTI优于放射线照相术的优势包括电离辐射，无胶片，实时诊断以及在检测x射线不明显的早期病变方面具有更高的灵敏度，如体外证明的那样。在这里，我们提出了一种处理在不同时间采集的DIFOTI图像以监视变化的方法。对于该应用而言，最重要的是图像帧的图案匹配，该图像帧相对于成像相机的视场而不会改变牙齿的平移和旋转，并且对照明源强度的变化具有鲁棒性。
我们的方法采用 :1) 小波模极大值表示用于牙齿图像的分割; 2) DIFOTI图像在空间域中灰度表示的第一和第二矩，估计牙齿的位置和方向; 3) 用于定量监测的多分辨率小波幅度表示。即使存在照明源强度变化，在体外也证明了这种小波表示可以促进检测在空间域中无法检测到的光透射的模拟临床变化。

BACKGROUND & AIMS: PURPOSE:This study aimed to explore the relationships among tooth replacement, number of present natural teeth, and sociodemographic and behavioral factors in an adult population in Bulgaria. MATERIALS AND METHODS:Quota sampling was used to recruit 2,531 dentate subjects aged 20 years and over from the capital city and four main urban centers, four towns, and seven small towns and villages of Bulgaria. Potential candidates for tooth replacement were classified as having functional dentitions (26 to 27 or 20 to 25 natural teeth present) or subfunctional dentitions (16 to 19 or 2 to 15 natural teeth present), not including third molars. Multiple logistic regression analyses were performed to determine the associations between tooth replacement and the factors of interest. RESULTS:Of the included subjects, 37% presented with tooth replacement, while 19% presented with fewer than 20 natural teeth. Molars were replaced significantly less often (P ≤ .017) than premolars and anterior teeth. The presence of tooth replacement was more likely in subjects with 2 to 15 teeth (odds ratio: 1.62) and less likely in subjects with 26 to 27 teeth (odds ratio: 0.29), but no significant difference was detected between subjects with 16 to 19 and 20 to 25 teeth. Tooth replacement was associated with age, occupational status, frequency of dental visits, and toothbrushing habits. CONCLUSIONS:In this Bulgarian population, the variables number of present teeth, age, dental visits, and toothbrushing were relevant factors with respect to tooth replacement. The cutoff value of 20 teeth did not discriminate high-risk from low-risk subjects.

背景与目标：