Plaque formation on surface modified dental implants

Bacterial adhesion on titanium implant surfaces has a strong influence on healing and long-term outcome of dental implants. Parameters like surface roughness and chemical composition of the implant surface were found to have a significant impact on plaque formation. The purpose of this study was to evaluate the influence of two physical hard coatings on bacterial adhesion in comparison with control surfaces of equivalent roughness. Two members of the oral microflora, Streptococcus mutans and Streptococcus sanguis were used. Commercially pure titanium discs were modified using four different surface treatments: physical vapour deposition (PVD) with either titanium nitride (TiN) or zirconium nitride (ZrN), thermal oxidation and structuring with laser radiation. Polished titanium surfaces were used as controls. Surface topography was examined by SEM and estimation of surface roughness was done using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Titanium discs were incubated in the respective bacterial cell suspension for one hour and single colonies formed by adhering bacteria were counted by fluorescence microscopy. Contact angle measurements showed no significant differences between the surface modifications. The surface roughness (Ra) of all surfaces examined was between 0.14 and 1.00 microm. A significant reduction of the number of adherent bacteria was observed on inherently stable titanium hard materials such as TiN and ZrN and thermically oxidated titanium surfaces compared to polished titanium. In conclusion, physical modification of titanium implant surfaces such as coating with TiN or ZrN may reduce bacterial adherence and hence improve clinical results.     

Control of plaque by chemical agents

Abstract The bacteria forming pathogenic dental plaque on the tooth surfaces have long constituted a challenge for researchers with an interest in chemical degerming agents. As the plaque grows outside the vascularized tissues, most trials have been conducted with locally applied antibiotics and antiseptics. When these are introduced into the oral cavity, they will, if effective, reduce the amount of supragingival plaque. No means have so far been demonstrated for chemical control of the plaque growing underneath the gingival margin. The results obtained from trials with various antibiotics have not been very promising, especially when compared to the risks involved. Also many antiseptics with an excellent degerming effect in vitro have been tried. Most of them have proved inactive in the human mouth. Failure may be due to the protective properties of mucus and other constituents of the saliva and, apparently, (o the short retention time of the antimicrobial agent in the oral cavity. Good retentive properties have been observed with chlorhexidine (CHX). Two daily 1-min rinses with a 0.2 % aqueous solution of CHX digluconate totally prevents growth of supragingival plaque and even when CHX has been included in. gels and dentifrices, a both statistically and clinically significant reduction in the amount of plaque has been demonstrated. At present CHX seems to be agent of choice in chemical control of supragingival dental plaque. However, due to some secondary side effects, it is mostly used only for short period treatments.     

The effect of a microbead dentifrice on microbial load in oral microenvironments

To cite this article:
Int J Dent Hygiene 9 , 2011; 136–142
DOI: 10.1111/j.1601‐5037.2010.00465.x
Sreenivasan PK, Haraszthy VI, Zambon JJ.The effect of a microbead dentifrice on microbial load in oral microenvironments. Abstract: Objectives: The human oral cavity contains several microenvironments or ecologic niches. While mechanical plaque control is well known to reduce the number of supragingival dental plaque bacteria, there is little data on antimicrobial effects in other oral ecologic niches. The present study examined the effects of mechanical plaque control using a microbead dentifrice on bacteria colonizing oral ecologic niches. Methods: Twenty‐two adults (aged 18–70 years) including nine generalized moderate chronic periodontitis subjects and 13 periodontally healthy subjects having average gingival indices ≥1 and plaque indices ≥1.5 completed a 1 week washout phase and refrained from oral hygiene the morning of baseline sample collection. Microbial samples from supragingival dental plaque, buccal mucosa, dorsal surface of the tongue and whole mixed saliva were obtained. Subjects brushed with a microbead dentifrice and, after 10 min, sampling was repeated. The number of anaerobic bacteria was determined by culture on non‐selective media and transformed to log₁₀ for statistical analyses. Results: Mechanical plaque control using the microbead dentifrice resulted in statistically significant reductions in bacterial numbers in each ecologic niche (P < 0.001). The greatest reduction in the number of viable bacteria occurred in samples taken from the buccal mucosa (97.22%) followed by a 95.22% reduction in supragingival plaque bacteria, a 94.51% reduction in the number of bacteria on the dorsal surface of the tongue and a 91.57% reduction in the number of bacteria in whole mixed saliva. Conclusions: Mechanical plaque control using a microbead dentifrice reduces microbial load in microenvironments throughout the human oral cavity.     

Experimental infective endocarditis induced by human supragingival dental plaque in rats

Human dental plaque is thought to contribute to disease, not only in the oral cavity but also at other body sites. To investigate the pathogenicity of dental plaque in tissues remote from the mouth, we examined the ability of human supragingival dental plaque to induce infective endocarditis (IE) in rats. In total, 15 out of 27 catheterized rats survived after intravenous injections with human supragingival dental plaque suspensions containing 3 x 10(6) colony-forming units (CFU) of bacterial cells. In surviving rats, infected vegetations were formed in all except one rat. The microbial composition of the infected vegetations was different from that of the respective dental plaque inocula, with Streptococcus oralis comprising the majority of the isolates. In rats affected with endocarditis, the aortic sinus was filled with fibrinous vegetation containing bacteria. Inflammatory cells infiltrated the aortic valve, the aorta adjacent to the valve, and the cardiac muscles. The inoculation of catheterized rats with a cell suspension of S. oralis isolate (5 x 10(6) CFU) was not lethal but capable of inducing endocarditis in all animals. The results suggest that if dental plaque were introduced into the bloodstream, it could serve as a potent source of bacteria causing IE in humans.     

Microbial vitality of supragingival dental plaque during initial stages of experimental gingivitis in humans

Although vital plaque micro-organisms are part of the natural ecosystem in the oral cavity they are also the key factor in the development of diseases induced by the human dental plaque. In a previous study (9) the portion of vital bacteria related to the total number of plaque micro-organisms (i.e. the microbial vitality) appeared low in small plaque samples. The objective of this investigation was to determine the exact relationship of microbial vitality and age of supragingival plaque during the early phases of human dental plaque formation. Between intervals of optimal oral hygiene, thirteen participants refrained from all oral hygiene measures for periods of 1, 2, 4, 8, 24 and 72 h. Plaque was completely sampled from a defined area situated on the vestibular surface of the teeth 13, 14, 15, 23, 24 and 25. The pooled plaque from these areas was immediately processed. Total bacterial counts (BC) as enumerated by darkfield microscopy, and colony-forming units (CFU) were recorded. The microbial vitality was calculated indirectly as plating efficiency (PE=CFU per BC) and directly assessed using a vital fluorescence (VF) technique. In the 1 h old plaque samples the median values of PE and VF were 29% and 18%, respectively. Thereafter, the microbial vitality increased significantly with plaque age. The 24 h old plaque samples yielded values of 77% (PE) and 62% (VF). It was concluded that the microbial vitality of the early dental plaque investigated was considerably lower compared to that of a more mature plaque.     

龋齿、牙周炎患牙和健康牙的菌斑生物膜特征

目的研究牙面菌斑生物膜特征与口腔疾病的关系。方法选择牙周健康而牙冠严重龋坏的龋齿5颗、无龋损而极度松动的牙周炎患牙6颗及正畸原因拔除的健康牙4颗,在扫描电镜下,观察分析龈上、龈下及移行生态区的菌斑生物膜特征。结果龋齿、牙周炎患牙和健康牙的牙面均观察到细菌混合物组成的菌斑生物膜,健康牙菌斑生物膜以球菌为主,放线菌和短杆菌少量;龋齿牙的龋坏处为坏死组织和细菌,龋边缘及龈沟处的球菌和短杆菌较健康牙多;牙周炎患者牙菌斑生物膜的细菌种类多,在龈上、龈下移行处可见典型的玉米棒状菌斑或以杆菌为主的紧密附着菌斑,龈下可见球菌、杆菌、梭菌及螺旋体等构成的复杂菌斑。结论龋齿、牙周炎患牙和健康牙菌斑生物膜细菌组成、集聚秩序和立体结构不同,菌斑生物膜的形成与细菌的附着、集聚、生长有关,也与局部病变密切相关。     

The role of sugar-rich diet and salivary proteins in dental plaque formation and oral health

BackgroundDental plaque is a complex colorless film of bacteria that develops on the surfaces of teeth. Different mechanisms of microbial adhesion to tooth surfaces exist. Both non-specific and specific types of adherence have been anticipated.HighlightThe present review evaluated the effect of sugar-rich diet and salivary proteins on oral hygiene and dental plaque development.ConclusionThe oral microbiota is essential for maintaining and reestablishing a healthy oral cavity. Different types of sugars have different effects on the inhibition and formation of dental plaque. The peptides, proteins, and amino acids secreted by parotid glands in the oral cavity facilitate neutralizing the acidity in dental plaque and preventing dental caries. A properly balanced diet is crucial for both a healthy oral cavity and the oral microbiome.     

Influence of optimal and excluded oral hygiene on early formation of dental plaque on plastic films

Abstract The influence of oral hygiene on early plaque formation has been studied. The amount and structure of dental deposits formed on plastic films were determined at two occasions with or without a preceding period of effective oral hygiene. Six human subjects developed plaque during 4 hours on plastic films applied to the buccal surfaces of premolars and cuspids. The plastic films with adhering deposits were processed for electron microscopy. In presence of healthy gingiva, the plastic films were covered by a surface coating of acellular material in or on which bacteria, epithelial cells and leukocytes were observed. The microorganisms were almost exclusively Gram-positive cocci. When plaque formation was preceded by a week of excluded oral hygiene, the deposits collected on the same teeth exhibited a threefold increase in the number of bacteria. The relative composition of the flora was altered, as evidenced by a higher number of Gram-negative cells as well as the occurrence of rods and filamentous organisms. The results indicate that neglect of oral hygiene favors an earlier establishment of a complex bacterial flora at the dento-gingival region of the buccal surfaces of premolars and cuspids.     

Clinical relevance of surface characteristics on the formation of plaque on teeth and implants

The mouth is, from an ecologic point of view, an 'open growth system' with a continuous transport of micro-organisms. To cause infection (caries or periodontitis) or even to survive in the oral cavity, micro-organisms need to attach to one of the available surfaces, otherwise they will be removed by a continuous flow of saliva. The mouth, with his ideal growth conditions for micro-organisms, has many places, called niches, that can be colonised with micro-organisms. It is not surprising that the mouth is being colonised with more then 400 different species. This article discusses successively colonisation of the oral cavity, bacterial adhesion, plaque growth from a clinical point of view, the influence of surface properties on the initial plaque adhesion and maturation, and finally important factors influencing the plaque formation on oral implants.     

Occurrence of Helicobacter pylori in dental plaque and saliva of dyspeptic patients

BACKGROUND: Helicobacter pylori infection in the stomach is associated with gastric and duodenal ulcers, gastric cancers and gastric lymphoma. The organism is transmitted by ingestion, but the oral-oral route and the fecal-oral route are also suggested. The prevalence of infection with H. pylori in developing countries, including Brazil, is higher than in developed countries. PURPOSE: This study aimed to evaluate the role of the oral cavity as a reservoir of this species, by evaluating the occurrence of H. pylori in supragingival dental plaque and in saliva of Brazilian dyspeptic patients, whether harboring the organism or not in the stomach. MATERIAL AND METHODS: Forty-nine patients reporting dyspeptic symptoms were subjected to oral clinical examination and collection of saliva and supragingival dental plaque samples prior to the endoscopic examination. The detection of H. pylori in oral samples was performed by PCR using 16S rRNA primers. The bacteria were detected in stomach by means of the rapid urease test. RESULTS: Helicobacter pylori was detected in the stomach of 20 of 49 subjects reporting dyspeptic symptoms. The organism was detected in only one supragingival plaque sample, obtained from a patient positive for the urease test in the stomach and in none of the salivary samples. CONCLUSION: Supragingival dental plaque and saliva may not be relevant reservoirs of H. pylori.     

Supra- and subgingival biofilm formation on implant abutments with different surface characteristics

PURPOSE: The aim of the present study was to establish a noninvasive method for quantitative analysis of supra- and subgingival biofilm formation on dental implants considering different surface modifications. MATERIALS AND METHODS: Patients of both sexes were included. They had to be in generally good health, partially edentulous, and the recipient of at least 1 screw-type implant with an abutment possessing supra- and subgingival areas. Healing abutments were inserted for 14 days. The abutment surfaces were divided into quadrants that were sandblasted, ground, acid-etched, and untreated (with the latter surface as a control). Biofilm formation on the healing abutments was analyzed using scanning electron microscopy, including secondary-electron and Rutherford backscattering-detection methods. Calculation of biofilm-covered surfaces was performed depending on grey-values, considering supra- and subgingival areas. After calculating absolute and relative biofilm-covered surfaces depending on localization, the influence of surface modification on biofilm formation was analyzed. RESULTS: Fifteen healing abutments were inserted in 11 patients. In all surface properties plaque adhesion in supragingival areas was significantly higher (17.3% +/- 23.1%) than in subgingival areas (0.8% +/- 1.0%). Biofilm accumulation in supragingival areas was significantly increasing by higher surface roughness, whereas this influence was not detected in subgingival areas. CONCLUSION: The described method is valuable for investigation of supra- and subgingival biofilm adhesion on surface-modified implant abutments. There was a significant influence of surface localization (supra- and subgingival) as well as surface modification on biofilm formation.     

Plaque development in relation to the periodontal condition and bacterial load of the saliva

AIM: To investigate the influence of the oral bacterial load on plaque development in various groups of periodontitis patients and in healthy subjects. MATERIAL AND METHODS: This study included subjects with a healthy periodontium, a healthy reduced periodontium after treatment, an inflamed reduced periodontium after treatment and untreated periodontitis. At the start of the study, subjects were instructed to rinse with 10 ml reduced transport fluid (RTF) for 10 s in order to evaluate the oral bacterial load. The microbiological evaluation included anaerobe culture and phase-contrast microscopy. Next, the amount of plaque and the clinical condition were evaluated. Thereafter, all supragingival plaque was removed and patients were instructed to refrain from all oral hygiene procedures for 19 h. Subsequently, the rinsing procedure and the evaluation of the amount of plaque were repeated. RESULTS: The amount of plaque that developed in 19 h was significantly higher in the untreated periodontitis group as compared with the two healthy groups. In case of an inflamed reduced periodontium, sites with deep pockets developed more plaque in 19 h than sites with shallow pockets. The number of bacteria present in the rinsing samples of the two inflamed groups was considerably higher than of the two periodontally healthy groups. A significant correlation was found between the bleeding index at intake and the plaque index at 19 h. No correlations were found between gingival recession and the bacterial counts at intake, and the plaque index at 19 h. CONCLUSION: The present findings support the concept that the periodontal condition is the dominating factor in relation to the rate of plaque formation. The number of bacteria present in the oral cavity as ascertained by means of a rinsing sample does not seem to play a role.     

三氯羟苯醚漱口液作用特点的研究

目的 研究新型三氯羟苯醚（triclosan）漱口液－力博漱口液的作用特点。方法 ①检查并记录受检者用药前后的牙菌斑指数和牙龋出血指数,观察临床疗效。②采集受检者用药前后受检者的龋下菌斑标本,厌氧环境下培养,计数菌落数（CUF／L）。对比用药前后的抑菌效果。③选择变形链球菌C、牙龋卟啉单胞菌等为实验菌株,以倍比稀释后的三氯羟苯醚漱口液和酸氯己定漱口液为抑菌物,厌氧培养后,观察抑菌环大小,对比两种漱口液对不同菌株的最低抑菌浓度。④在光滑附着板上培养变形链球菌,形成细菌斑膜后,将附着板置于三氯羟苯醚漱口液、醋酸氯己定漱口液和生理盐水中,观察细菌脱落情况。结果 ①三氯羟苯醚漱口液含漱治疗牙龋炎症临床有效,可降低牙菌斑指数及牙龋出血指数。②使用三氯羟苯醚漱口后,口腔致病菌的培养计数有所减少。③三氯羟苯醚漱口液对变形链球菌C的最低抑菌浓度低于醋酸氯己定漱口液,对牙龋卟啉单胞菌的最低抑菌浓度高于醋酸氯己定漱口液。④在三氯羟苯醚漱口液中,附着板上的细菌膜最容易脱落,三氢羟苯醚漱口液的抗细菌附着作用强于醋酸氯己定漱口液和生理盐水。结论     

Fibronectin levels in stimulated whole-saliva and their relationship with cariogenic oral bacteria

AIM: Fibronectin is a multifunctional glycoprotein that plays a fundamental role in mechanism of cellular union and in bacterial adhesion in the oral cavity. The aim of this study was to test the clinical relationship between fibronectin concentration in stimulated whole-saliva and the number of Mutans streptococci bacteria. PARTICIPANTS: The sample consisted of 167 children aged 12 years. METHODS: Saliva samples were collected from the subjects. Bacterial quantification was carried out using a semiquantitative method (Dentocult SM, Vivadent). Fibronectin was measured by the ELISA method with modifications. RESULTS: An inverse clinical relation was found between the levels of soluble fibronectin and the number of SM colony forming units. CONCLUSIONS: Bacterial counts sufficiently high to destroy the protein films increase bacterial binding to dental surfaces, thereby contributing to the regulation of bacterial plaque composition and its pathogenic potential. This capacity of glycoproteins to reduce the adhesion of microorganisms to the oral tissues and favour macrophage action supports the hypothesis that such proteins contribute to the first line of immune defence together with secretory antibodies.     

牙体充填材料表面粗糙度对常见口腔链球菌黏附力的影响

目的 采用原子力显微镜（AFM）检测常见口腔链球菌属与不同表面粗糙度的光固化复合树脂及玻璃离子水门汀（GIC）之间的黏附力。方法 将光固化复合树脂和GIC样本表面梯度抛光,根据最终表面粗糙度不同分为300、200、100和10 nm组,使用AFM观察其表面形貌。采用先锋菌（血链球菌、缓症链球菌）和致龋菌（变异链球菌、表兄链球菌）制作细菌改性探针,通过AFM获得力-距曲线测量细菌与树脂和GIC样本表面的黏附力。对材料表面粗糙度测量值进行方差分析,细菌黏附力进行Kruskal-Wallis非参数检验,同时采用Dunn’s进行组间两两比较,并对表面粗糙度与细菌黏附力进行相关性分析。结果 随材料表面粗糙度增加,细菌的黏附力增大,4种细菌的黏附力均在300 nm的材料表面达到最大值;在10和300 nm组的GIC表面,变异链球菌的黏附力由0.578 nN增加到2.876 nN。4种细菌在树脂表面的黏附力略大于GIC,先锋菌的黏附力略大于致龋菌,组间差异均在200和300 nm组时较明显。结论 材料表面粗糙度对细菌黏附力的影响较大,二者有明显的相关性;GIC对细菌的黏附性较复合树脂低;材料表面粗糙度对致龋菌的影响小于先锋菌。     

Reduced dental plaque accumulation on composite gold alloy margins

Restoration of tooth surfaces with materials that inhibit formation of heavy bacterial plaque accumulations could be important in the treatment of patients with existing oral disease or in reducing the likelihood for periodontal disease. Captek is a dental gold composite material used to produce copings for ceramometal restorations that has been reported to inhibit plaque accumulation. In this study, the oral bacteria of nine periodontally healthy subjects with a total of 42 gold composite copings were sampled. Contralateral teeth with normal tooth surfaces were also sampled as controls. The quantitative presence of forty bacteria was determined in each sample by DNA:DNA hybridization. The results indicated that the porcelain/gold composite alloy coping surfaces had significantly fewer bacteria than the control normal tooth surfaces (71% reduction). The percentage composition, however, did not differ significantly between surfaces.     

The oral cavity—a key system to understand substratum-dependent bioadhesion on solid surfaces in man

One of the greatest challenges in life sciences and biomaterials research is adhesion of biomolecules and bacteria to solid surfaces in aqueous solutions. An example concerning everybody is biofilm formation in the oral cavity on dental materials and dental hard substances, respectively. The main characteristics typical for any bioadhesion can be observed excellently in the oral cavity. Initially, a proteinaceous layer termed pellicle is formed. It mediates the interactions between solid substrata, oral fluids and microorganisms. Numerous different materials with differing physico-chemical properties and possible impact on the acquired pellicle are present in the oral cavity such as enamel, dentine, restorative materials or dental implants. Despite the fact that in vitro studies demonstrate considerable differences of experimental pellicles formed on these materials, the in situ pellicles seem to be relatively similar and level off the different properties of the underlying substrates. However, the bacterial colonisation of pellicle-coated surfaces under in vivo conditions differs considerably. Long-range forces and detachment of biofilm layers may account for this phenomenon despite the masking effect of the pellicle. Accordingly, low-energy surfaces are desirable for restorative materials exposed to the oral cavity to minimise bacterial adhesion. The oral cavity is an easy accessible in vivo model for understanding bioadhesion and for investigation of protein–surface interactions noninvasively. For evaluation of biofilm formation on dental materials, in situ or in vivo studies are preferable.     

Adherence of Streptococcus sanguis

The presence of adhesins on the cell surface of S. sanguis enables the organism to grow and survive in the oral cavity. Many workers are now actively involved in attempting to characterise these adhesins and the molecular basis for adherence of various streptococci. The complexity of the adhesion processes is underlined by the many varied opinions as to the nature of the molecular components and biochemical interactions that are involved. Understanding the molecular mechanisms involved in bacterial adherence and in dental plaque formation will have significant impact on the prevention and treatment of oral diseases.     

Bacterial morphotypes of 3-day old plaque in Chinese

Abstract The aim of the this study was to estimate the % distribution of bacterial morphotypes of supragingival plaque in Chinese subjects after 3 days of no oral hygiene. 36 dental students, hygienists or dental surgery assistants (mean age: 24.3 years) were recruited. Prophylaxis and oral hygiene reinforcement were given 1X a week for 3 weeks to obtain gingival health and a 3-day period without any plaque control started afterwards. Al the end of the 3-day period, the plaque along the gingivul margin of the upper right central incisor was removed and direct Gram stained smears were prepared for light microscopy. Bacteria were classified as gram-positive or gram-negative cocci, rods, filaments, fusiform organisms, spirilla or spirochetes. A differential count of 200 organisms from 3-6 microscopic fields was performed and the results expressed as a‘M, of the organisms counted. Results from the 36 direct smears showed approximately 83% (range: 52%-96%.) of the organisms to be gram-negative while gram-positive bacteria comprised only a minority of about 12% (range: 0.7%-43%). This result is remarkably different from previous reports from the West where gram-positive bacteria were the predominant bacterial types noted in early supragingival plaque. Further longitudinal studies involving both microscopy and bacteriological culture will be necessary to confirm this finding.