不同托槽结扎材料在固定矫治中对牙体健康影响的比较研究

目的 分析固定矫治中用不同结扎材料对牙体健康的影响.方法 随机选择固定矫治患者30名,在每位患者左右牙弓分别使用橡皮圈和金属丝结扎托槽.测定矫治开始及6个月时托槽周围的菌斑进行细菌厌氧培养,研究牙面变形链球菌附着情况的变化,并进行对比.结果 固定矫治器粘结后托槽周围牙面菌斑变形链球菌数量和在总菌中的百分比有显著增高,但两种材料牙面菌斑比较无明显差异.结论 固定矫治器粘结后患者龋易感性增强.结扎材料的选择并不会对相应牙面菌斑的致龋性产生直接的影响.     

固定矫正青少年龋活性临床研究

目的通过检测29名12～18岁固定矫正青少年的龋活性,了解固定矫正与龋活性的关系.方法测定变形链球菌菌落数、菌斑产酸能力和唾液缓冲能力,用团体T检验的方法进行统计.结果正常青少年对照组口腔内变形链球菌菌落数明显少于固定矫正青少年组,而唾液PH值明显大于固定矫正组,统计学上有显著性差异(P＜0.01).两组菌斑产酸能力无统计学显著性差异,正常青少年唾液缓冲能力虽然高于固定矫正组,但两组之间无显著性差异(P＜0.05).结论结果显示固定矫正青少年对龋病的易感性增加.     

Nd:YAG激光和氟涂料对细菌在牙釉质上黏附的影响

细菌黏附是导致临床正畸患者釉质脱矿的重要环节,细菌在釉质上的黏附速度和程度对菌斑的形成具有决定性意义。一些影响细菌在牙面上黏附效果的因素可以影响菌斑的结构和构成,进而影响酸性代谢物的产生,关系到对釉质的伤害[1]。从20世纪末开始,学者们通过模拟自然口腔的生态环境,研究各种致龋因素的作用和龋病病变的特征,并鉴定各种防龋方法的效能。     

窝沟封闭剂在乳牙龋坏防治中的作用

目的探讨窝沟封闭剂在乳牙龋坏防治中的作用。方法临床在门诊选择2—5岁的儿童上颌乳前牙无龋或可疑龋400例，试验组与对照组各200例。采用晨光医用高分子制药厂生产的EB型防龋涂料，对儿童乳前牙进行牙体预备、酸蚀、涂布。结果儿童乳前牙使用涂料后浅龋发生率明显下降，涂膜脱落后龋病也不会立刻出现。涂膜局部脱落后也有一定的防龋作用，虽然涂膜完全脱落后防龋作用消失，但并不增加牙齿对龋病的易感性。结论窝沟封闭剂可以抑制儿童乳上前牙龋的发生，帮助儿童度过龋病易感期，以达到乳、恒牙正常替换的目的。     

木糖醇对变形链球菌母婴传播的影响

目的观察母亲产后3个月使用木糖醇口香糖和氟化泡沫对婴幼儿口腔内变形链球菌的影响,为制定婴幼儿防龋计划提供依据。方法选择产后唾液中高水平变形链球菌的母亲96例（变形链球菌≥105cfu/ml）,随机分为3组,木糖醇组（X组）、氟化物组（F组）和对照组（C组）,每组32例。X组在产后3个月开始餐后咀嚼木糖醇口香糖至婴儿2岁,3次/d,20min/次;F组在产后6、12、18、24个月使用1.23%的氟化泡沫;C组保持原有口腔卫生不变。在婴儿6、12、18、24个月,分别检测其菌斑中变形链球菌量,计算其定植情况。结果在儿童2岁时,X组变形链球菌的定植率为12.5%,F组为53.13%,C组为71.88%。X组的MS阳胜率于F组和C组比较,差异有统计学意义（P〈0.01）。结论产后唾液中高水平变形链球菌的母亲餐后咀嚼木糖醇口香糖可以延迟婴幼儿口腔内变形链球菌的定植,从而减少婴幼儿龋的发生。     

中药五倍子对口腔致龋菌影响的体外实验研究

目的：研究五倍子对致龋菌生长、产酸及产胞外多糖的影响，探讨五倍子是否能有效调节口腔菌群生态平衡。方法：测定五倍子对3种主要致龋菌－变形链球菌、粘性放线菌和血链球菌的最低抑菌浓度MIC。再测定低于MIC的4个浓度的五倍子对3种细菌产酸及产生水不溶性多糖能力的影响。结果：五倍子对3种细菌的生长、产酸均有一定的抑制作用，且能够有效抑制变形链球菌产生水不溶性葡聚糖。结论：五倍子能有效抑制变形链球菌、粘性放线菌和血链球菌的生长、产酸及抑制变形链球菌产水不溶性葡聚糖。     

蜂胶与柠檬提取物混合液对变形链球菌作用的体外研究

目的：探讨蜂胶与柠檬提取物混合液对变形链球菌（Streptococcus mutans．S．m）生长、产酸的抑制作用,以及对主要致龋毒力因子乳酸脱氢酶（Lactate dehydrogenase,LDH）活性的影响。方法：分别测定蜂胶、柠檬以及两者混合液的最小抑菌浓度（MIC）值,通过分级抑制浓度（FIC）指数来判断两者联合使用对S．m（ATCC25175）生长作用的影响,并在低于混合液最小抑菌浓度的混合液中培养S．m,用pH计测其培养前后的ApH（酸碱度的变化）,同时采用还原性辅酶I氧化法测定混合液对S．m乳酸脱氢酶活性的影响。结果：蜂胶与柠檬提取物混合液对变形链球菌的体外抗菌活性具有相加作用,随着菌混合液浓度的升高,△pH和乳酸脱氢酶活性逐渐降低。结论：蜂胶与柠檬提取物混合液能有效的抑制变形链球菌的生长,对其产酸及乳酸脱氢酶有较强的抑制作用。     

某市儿童涂氟前后患龋状态及龋齿活跃度的比较

<正>龋病是一种感染性疾病,尤其儿童龋病更是多因素共同作用的结果[1]。龋齿的活跃性检测,主要是变形链球菌与乳酸杆菌等致龋菌产酸能力的强弱或数量多少检查,能够预测新发龋齿的患病率。龋齿活跃性试验法(Cariostat)是下野等研究者开发研制[2],通过测定菌斑中致龋菌的酸产生能来判定龋齿活动性强弱的,因为操作简便,价廉,在日本已经被广泛用于临床。氟化物对于釉质的发育及矿化有着重要的作用,可以增强牙齿的     

天然药物防龋作用的研究进展

龋病是人类最常见的口腔疾病之一,药物防龋是龋病防治的重要手段。近年来,利用天然药物防龋的研究受到国内外学者的广泛关注,并取得很大进展。多种天然药物能够抑制主要致龋菌的生长及其产酸、产糖、黏附能力,抑制生物膜形成或清除已形成生物膜,抑制牙釉质脱矿并促进釉质再矿化。但有关天然药物毒性、天然药物对混合生物膜的作用、天然药物之间的协同作用及天然药物防龋与其他防龋方式的联合还有待进一步研究。该文从天然药物对致龋菌和对牙釉质的作用两方面进行阐述。     

第三讲社区常见疾病第八章口腔常见疾病

第一节龋病龋病是牙体硬组织在以细菌为主的多因素影响下,发生脱钙崩解、造成牙齿缺损、破坏的一种慢性进行性疾病。龋病是人类多发病、常见病之一,主要的致龋菌是变形链球菌,其次是乳酸杆菌和放线菌。牙体组织一旦形成龋洞,因缺乏自身修复能力,不可能自行恢复。     

Discovery of Potent Inhibitors of Streptococcus mutans Biofilm with Antivirulence Activity

Dental caries is a bacterial infectious disease characterized by demineralization of the tooth enamel. Treatment of this disease with conventional antibiotics is largely ineffective as the cariogenic bacteria form tenacious biofilms that are resistant to such treatments. The main etiological agent for dental caries is the bacterium Streptococcus mutans. S. mutans readily forms biofilms on the tooth surface and rapidly produces lactic acid from dietary sucrose. Glucosyl transferases (Gtfs) secreted by S. mutans are mainly responsible for the production of exopolysaccharides that are crucial for the biofilm architecture. Thus, inhibiting S. mutans’ Gtfs is an effective approach to develop selective biofilm inhibitors that do not affect the growth of oral commensals. Herein, we report a library of 90 analogs of the previously identified lead compound, G43, and exploration of its structure activity relationships (SAR). All compounds were evaluated for the inhibition of S. mutans biofilms and bacterial growth. Selected compounds from this library were further evaluated for enzyme inhibition against Gtfs using a zymogram assay and for growth inhibition against oral commensal bacterial species such as Streptococcus gordonii and Streptococcus sanguinis. This study has led to the discovery of several new biofilm inhibitors with enhanced potency and selectivity. One of the leads, III_F1, showed marked reduction in buccal, sulcal, and proximal caries scores in a rat model of dental caries.     

Streptococcus mutans and Streptococcus sobrinus are able to adhere and invade human gingival fibroblast cell line

Streptococcus mutans and Streptococcus sobrinus, the principal etiologic agents of caries decay of teeth, are generally acquired in oral cavity at the moment of tooth eruption. However, as S. mutans has been detected in oral cavity of predentate children, the eruption of teeth seems not to be a necessary prerequisite, suggesting that this species may be not confined to dental plaque. Here, we evaluate the ability of S. mutans and S. sobrinus in planktonic and biofilm lifestyle to adhere, invade and survive within human gingival fibroblast (HGF-1) cells. Planktonic and biofilm streptococci adhered and invaded host cells to different extents, showing higher efficiencies of biofilm than planktonic counterparts. Moreover, planktonic and biofilm streptococci showed the same percentage of survival within host cells. Transmission electron and confocal microscopy observations confirmed intracellular localization of planktonic and biofilm bacteria. The adhesion, invasion and survival abilities within human oral cells may be considered S. mutans and S. sobrinus virulence mechanisms to colonize and persist in the oral cavity in the absence of tooth surface.     

Comparative evaluation of in-vitro effects of Brazilian green propolis and Baccharis dracunculifolia extracts on cariogenic factors of Streptococcus mutans

Streptococcus mutans triggers dental caries establishment by two major factors: synthesis of organic acids, which demineralize dental enamel, and synthesis of glucans, which mediate the attachment of bacteria to the tooth surface. Propolis is a natural product that may prevent dental caries. Baccharis dracunculifolia DC (Asteraceae), a native plant from Brazil, is the most important botanical origin for the production of green propolis (Brazilian propolis) by honeybees. However, whether B. dracunculifolia (Bd) has an anticariogenic effect, like green propolis, remains unknown. Herein, we have made a comparative evaluation of the effects of extracts from green propolis and Bd on the glucan synthesis and acidogenic potential of S. mutans. The inhibitory effects of the extracts on bacterial acid production were evaluated through the potentiometric measurement of pH from bacterial suspensions treated with serial concentrations of both extracts. Besides presenting close inhibitory values at the same concentration range, Bd leaf rinse and green propolis extracts had similar IC(50) values (0.41 and 0.34 mg/ml, respectively). Both extracts produced a bacteriostatic effect on S. mutans cultures at a concentration of 0.40 mg/ml. Estimated inhibitory values of green propolis and Bd leaf rinse extracts on the synthesis of insoluble glucans (IC(50)=12.9 and 25.0 microg/ml, respectively) and soluble glucans (IC(50)=50.4 and 49.1 microg/ml, respectively) were not significantly different from each other at p<0.05. The results demonstrate that Bd leaf rinse and green propolis extracts have similar inhibitory effects on the S. mutans cariogenic factors evaluated herein, and allowed us to suggest that Bd leaves may be a potential source for pharmaceutical products employed for this purpose.     

氟保护漆儿童防龋的应用

目的评价应用氟保护漆开展集体儿童口腔保健的效果。方法观察组(600例)给予氟保护漆防龋治疗每丰年一次,共观察2年;对照组(600例)只做早晚刷牙等日常口腔护理。结果观察组4岁、5岁、6岁年龄组儿童的患龋情况分别比对照组下降10．52％、7．74％、8．76％,呈明显下降趋势。结论氟保护膝防龋效果明显,操作简便,适合推广。     

安徽省岳西县某贫困山村居民口腔健康状况流行病学调查

目的 了解安徽省岳西县某贫困山区居民口腔健康状况,及人们对口腔健康知识的知晓情况,了解当地居民龋病、牙周病的发病情况,指导开展相关口腔健康保健工作.方法 参照《第3次全国口腔健康流行病学抽样调查方案》,采用普查的调查方法,用SPSS 16.0软件对数据进行统计分析,龋病以患龋率和龋均数,牙周病以牙龈出血、牙结石和牙周袋的检出率做为统计指标.结果 共调查某贫困山村居民487例,总患龋率为63.66%,受检者龋均为2.07颗,牙龈出血检出率为14.37%,牙结石检出率为95.48%,牙周袋检出率为16.02%,总体失牙率为72.69%,全口无牙率为1.64%,义齿修复率为5.34%.结论 患龋率,牙龈出血、牙结石和牙周袋检出率和全口无牙率均接近第3次全国口腔健康流行病学抽样调查结果,但失牙率高、义齿修复率较低,应加强山区居民口腔健康防治工作,改善贫困山区居民口腔医疗条件.     

Effects of oral clotrimazole troches on the pharmacokinetics of oral and intravenous midazolam

AIMS

The aim of the study was to determine the effects of oral clotrimazole troches on the pharmacokinetics of oral and intravenous midazolam in the plasma.

METHODS

We conducted a randomized, open-label, four-way crossover study in 10 healthy volunteers. Each volunteer received oral midazolam 2 mg or intravenous midazolam 0.025 mg kg⁻¹ with and without oral clotrimazole troches 10 mg taken three times daily for 5 days. Each study period was separated by 14 days. Serial blood samples were collected up to 24 h after oral midazolam and 6 h after intravenous midazolam. Plasma concentrations for midazolam and its metabolite 1-hydroxymidazolam were measured and fitted to a noncompartmental model to estimate the pharmacokinetic parameters.

RESULTS

Ten healthy volunteers aged 21–26 years provided written informed consent and were enrolled into the study. Clotrimazole decreased the apparent oral clearance of midazolam from 57 ± 13 l h⁻¹[95% confidence interval 48, 66] to 36 ± 9.8 l h⁻¹ (95% confidence interval 29, 43) (P= 0.003). These changes were accompanied by a decrease in the area under the concentration–time curve (mean difference 22 µg h⁻¹ l⁻¹, P= 0.001) and bioavailability (mean difference 0.21, P= NS). There were no significant differences in the systemic clearance of midazolam with or without clotrimazole troches.

CONCLUSIONS

Oral clotrimazole troches decreased the apparent oral clearance of midazolam; no significant differences in the systemic clearance of midazolam were found.     

Design and Characterization of an Acid-Activated Antimicrobial Peptide

Dental caries is a microbial biofilm infection in which the metabolic activities of plaque bacteria result in a dramatic pH decrease and shift the demineralization/remineralization equilibrium on the tooth surface towards demineralization. In addition to causing a net loss in tooth minerals, creation of an acidic environment favors growth of acid-enduring and acid-generating species, which causes further reduction in the plaque pH. In this study, we developed a prototype antimicrobial peptide capable of achieving high activity exclusively at low environmental pH to target bacterial species like Streptococcus mutans that produce acid and thrive under the low pH conditions detrimental for tooth integrity. The features of clavanin A, a naturally occurring peptide rich in histidine and phenylalanine residues with pH-dependent antimicrobial activity, served as a design basis for these prototype ‘acid-activated peptides’ (AAPs). Employing the major cariogenic species S. mutans as a model system, the two AAPs characterized in this study exhibited a striking pH-dependent antimicrobial activity, which correlated well with the calculated charge distribution. This type of peptide represents a potential new way to combat dental caries.     

纳米羟基磷灰石牙膏对人工龋再矿化研究

目的:用正畸拔除前磨牙形成早期人工龋,再使用含纳米羟基磷灰石(NanoHA)牙膏和空白牙膏分别进行再矿化实验。方法:然后利用显微镜、显微硬度计、扫描电子显微镜等检测手段检测矿化效果。结果表明:含纳米羟基磷灰石牙膏可提高釉质的抗龋力,并能使脱矿的牙釉质再矿化。     

Effect of the antimicrobial decapeptide KSL on the growth of oral pathogens and Streptococcus mutans biofilm

Dental caries and periodontitis are common oral bacterial infectious diseases. Their prevention and treatment requires control of the causative pathogens, such as Streptococcus mutans and Porphyromonas gingivalis, that exist within dental plaque. As one of the attractive future substitutes for conventional antibiotics, antimicrobial peptides (AMPs), both natural and synthetic, have been widely tested and used for controlling bacterial infections. In this study, we investigated the antimicrobial activity of KSL (KKVVFKVKFK-NH(2)), a novel AMP, against several major cariogenic and periodontopathogenic bacteria as well as Candida albicans in vitro. Streptococcus mutans, the causative agent of dental caries, was chosen for in-depth testing. Bacterial susceptibility and time-kill assays were performed to investigate the sensitivity of S. mutans to KSL. The effect of KSL on biofilm formation and on pre-formed biofilm was also examined. For biofilm studies, confocal laser scanning microscopy (CLSM) was used to observe and analyse bacterial biofilm. The results showed that KSL had antimicrobial activity against a variety of oral bacteria and fungi. Streptococcus mutans and Lactobacillus acidophilus were the most susceptible strains to KSL peptide [minimum inhibitory concentration (MIC) of 0.0625 mg/mL] compared with other species tested (MICs of 0.125-1mg/mL). KSL also inhibited S. mutans biofilm formation, with a minimum biofilm inhibition concentration of 0.0625-0.125 mg/mL, and reduced 1-day-old developed S. mutans biofilm, with a minimum biofilm reduction concentration of 0.25-0.5mg/mL. CLSM images showed that KSL significantly reduced the viability of biofilm cells. This study suggests that KSL may have a potential clinical application in treating dental caries by killing S. mutans within dental plaque.     

A nonstaining and tasteless hydrophobic salt of chlorhexidine

Chlorhexidine (CHX) remains one of the most effective and widely used antiplaque agents around the world, although its side effects still limit a long-term usage as the patient compliance for oral treatment with CHX. We hypothesize that a less water-soluble tetracation salt of CHX might be able to interact weakly with tooth enamel and oral taste cells, reducing those undesirable side effects of CHX. The chlorhexidine tetrapalmitate (CHXTP) was obtained and the antimicrobial activity was evaluated by hole-plate diffusion method and twofold tube dilution method; for measurement of its propensity to stain, we used the in vitro method of polymethylmethacrylate blocks in an infusion with black tea solution; the rate of its removal from oral cavity was studied by high-performance liquid chromatography measurement of CHX extracted from human saliva samples; and its effect on the human taste perception was evaluated by taste confusion matrix method. The results showed that CHXTP salt is very active against Streptococcus mutans, with no interference on taste perception and a low tendency to stain; however, chlorhexidine digluconate shows a better retention in saliva. The use of polyvinylpyrrolidone turned possible a nonstaining and tasteless CHXTP formulation to linger in mouth.