Correlations between bacterial levels in autologous subgingival plaque and saliva of adult Sudanese

The aim of this study was to assess levels of oral bacteria and their correlations in paired samples of saliva and subgingival plaque in a population of adult Sudanese. Whole saliva and pooled subgingival plaque samples from six probing sites of one tooth in each jaw were obtained from 56 Sudanese adults (mean age 35.2+/-8.9 years). Levels of 24 oral bacteria in the autologous saliva and pooled plaque sample of each subject were assessed by DNA probes and checkerboard DNA-DNA hybridization. There were significantly ( P< or =0.01) higher percentages of subjects with > or =10(5) bacterial cells of Prevotella intermedia, Campylobacter rectus, Veillonella parvula, Streptococcus mutans, Lactobacillus acidophilus, Streptococcus anginosus, Streptococcus salivarius, and Leptotrichia buccalis and significantly ( P< or =0.01) lower percentages with Treponema denticola in saliva than in subgingival plaque. The detection frequencies at > or =10(6) bacterial cells were significantly higher for Selenomonas sputigena, S. anginosus, Streptococcus sanguis, and S. salivarius and significantly lower for Porphyromonas gingivalis in saliva than in subgingival plaque ( P< or =0.01). Porphyromonas gingivalis, Fusobacterium nucleatum, S. sputigena, S. sanguis, and Streptococcus mitis demonstrated significant ( P< or =0.05) positive correlations between their levels in plaque and saliva. This study indicates that the levels of P. gingivalis, F. nucleatum, S. sputigena, S. sanguis, and S. mitis correlate significantly in saliva and subgingival plaque and that higher accuracy of detection and assessment of the levels of these bacteria in the oral cavity may be achieved by concurrent sampling of saliva and subgingival plaque.     

Profile of subgingival microbiota in children with primary dentition

Eruption of primary teeth has a great influence on the oral environment by providing suitable niches for bacterial colonization. The aim of the study was to investigate the composition of the subgingival microbiota of primary incisors, canines and molars in 40 systemically healthy children aged 4-5 yr, chosen randomly. Subgingival plaque samples were taken from the mesiobuccal sites of primary incisors (61, 81), canines (53, 73) and molars (64, 84). The samples were cultured for bacterial isolation anaerobically and in 10% CO2 plus air using selective and non-selective media. Forty-one different microbial species were isolated. Gemella morbillorum and Peptostreptococcus magnus were statistically significantly more frequently detected in incisors while P. micros, Streptococcus intermedius, Bacteroides forsythus, Fusobacterium nucleatum, Prevotella loeschei, P. melaninogenica and Selenomonas sputigena were more frequently detected in molars. The bacterial species S. constellatus, G. morbillorum and P. magnus were isolated in greater numbers in incisors and P. micros, S. intermedius, Campylobacter concisus, Bacteroides egertheii, B. forsythus, P. oralis and S. sputigena were isolated in greater numbers in molars, respectively. Cluster analysis revealed 4 clusters in which 6-7 bacterial species were elevated above mean levels. Cluster I was predominated by S. constellatus, S. mitis, S. sanguis, G. morbillorum, P. melaninogenica and P. oralis; cluster II was predominated by S. sanguis, Actinomyces naeslundii, Capnocytophaga gingivalis, C. ochracea and P. intermedia; cluster III was predominated by S. mitis, C. ochracea, F. nucleatum, P. loeschei, P. melaninogenica and P. oralis; and finally cluster IV was predominated by S. sanguis, C. gingivalis, Veillonella parvula, Campylobacter gracilis, F. nucleatum and P. intermedia. The bacterial species S. constellatus, P. micros, Pseudoramibacter alactolyticus, Eikenella corrodens and F. nucleatum were associated with non-bleeding sites while S. intermedius, C. concisus, P. intermedia and P. loescheii were found more frequently in bleeding sites.     

Acid tolerance and acid-neutralizing activity of Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum

The tolerance to acid and the acid-neutralizing activity of three important periodontopathic bacteria, Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum were studied. P. gingivalis strains grew only at neutral pH and did not utilize glucose, whereas strains of P. intermedia and F. nucleatum could grow under acidic conditions and increased their growth by utilizing glucose. P. gingivalis tended to raise the culture pH during growth. P. intermedia and F. nucleatum raised the culture pH during growth in the absence of glucose, while in the presence of glucose they decreased the pH. Resting cell suspensions of all the bacteria raised the pH in the presence of tryptone and casamino acids. Acid-neutralizing activity was confirmed by measuring base production at a fixed pH with a pH-stat. During neutralization, the cells produced cytotoxic substrates, ammonia and organic acids (butyric, isobutyric and isovaleric acids by P. gingivalis ; isovaleric and succinic acids by P. intermedia ; propionic and butyric acids by F. nucleatum ). These findings suggest that deamination of amino acids into ammonia and organic acids occurs simultaneously with base production, resulting in acid neutralization. These results could partially explain the survival of P. intermedia and F. nucleatum in both supragingival and subgingival plaque and the apparent restriction of P. gingivalis to subgingival plaque. The former bacteria may aid in creation of an environment fostering colonization of subgingival plaque by P. gingivalis.     

牙周菌斑生物膜的体外模型建立

目的 观察血链球菌、牙龈卟啉单胞菌和具核梭杆菌在人工牙根面上随培养时间变化形成单菌种、双菌种和三菌种生物膜的能力,期望在体外建立龈下菌斑生物膜模型.方法 培养血链球菌、牙龈卟啉单胞菌和具核梭杆菌试验菌株,制备胶原包被羟磷灰石的人工牙根面,在人工牙根面上培养形成试验菌株的单菌种、双菌种和多菌种生物膜,并用扫描电镜观察三种试验菌株分别在培养24、48和72 h后形成单菌种、双菌种和三菌种生物膜的情况.结果 单独培养24h的血链球菌在人工牙根面上形成的完整生物膜,具备三维立体结构;培养48和72 h后,细菌密度逐渐增大,生物膜更加成熟.单独培养48 h的牙龈卟啉单胞菌形成的完整生物膜,具备三维立体结构;培养72 h后,细菌密度有所降低.牙龈卟啉单胞菌和具核梭杆菌培养24h形成的完整的双菌种生物膜,具备三维立体结构;培养48和72h后已看不出完整的生物膜结构,两菌的数量大幅度降低.血链球菌、牙龈卟啉单胞菌和具核梭杆菌在培养24h时形成的较完整的三菌种生物膜,初步具备三维立体结构;三菌中,血链球菌、具核梭杆菌所占比列远大于牙龈卟啉单胞菌;培养48 h后,三菌种生物膜更加成熟,牙龈卟啉单胞菌所占比例有所增加,此时的生物膜已具备三维立体结构;培养72 h后,三菌种仍保持较完整的生物膜结构,但数量均有所下降.结论 血链球菌、牙龈卟啉单胞菌和具核梭杆菌在培养24h时间点已基本形成了完整的单菌种、双菌种和三菌种生物膜结构,故在今后建立龈下菌斑生物膜模型时可选取24h这一时间点.     

牙周菌斑生物膜的体外模型建立

目的观察血链球菌、牙龈卟啉单胞菌和具核梭杆菌在人工牙根面上随培养时间变化形成单菌种、双菌种和三菌种生物膜的能力,期望在体外建立龈下菌斑生物膜模型。方法培养血链球菌、牙龈卟啉单胞茵和具核梭杆菌试验菌株,制备胶原包被羟磷灰石的人工牙根面,在人工牙根面上培养形成试验菌株的单菌种、双菌种和多菌种生物膜,并用扫描电镜观察三种试验菌株分别在培养24、48和72h后形成单菌种、双菌种和三菌种生物膜的情况。结果单独培养24h的血链球菌在人工牙根面上形成的完整生物膜,具备三维立体结构;培养48和72h后,细菌密度逐渐增大,生物膜更加成熟。单独培养48h的牙龈卟啉单胞菌形成的完整生物膜,具备三维立体结构;培养72h后,细菌密度有所降低。牙龈卟啉单胞菌和具核梭杆菌培养24h形成的完整的双菌种生物膜,具备三维立体结构;培养48和72h后已看不出完整的生物膜结构,两菌的数量大幅度降低。血链球菌、牙龈卟啉单胞菌和具核梭杆菌在培养24h时形成的较完整的三菌种生物膜,初步具备三维立体结构;三菌中,血链球菌、具核梭杆菌所占比列远大于牙龈卟啉单胞菌;培养48h后,三菌种生物膜更加成熟,牙龈卟啉单胞菌所占比例有所增加,此时的生物膜已具备三维立体结构;培养72h后,三菌种仍保持较完整的生物膜结构,但数量均有所下降。结论血链球菌、牙龈卟啉单胞菌和具核梭杆菌在培养24h时间点已基本形成了完整的单菌种、双菌种和三菌种生物膜结构,故在今后建立龈下菌斑生物膜模型时可选取24h这一时间点。     

Transition dynamics in experimental gingivitis in humans

This study was conducted in order to investigate the dynamics of the gingival inflammatory status during periods of plaque accumulation and thorough oral hygiene. After a period of prophylaxis, 42 volunteers were asked to abstain from all oral hygiene measures for 2 weeks, whereafter oral hygiene was reinstituted. In the absence of oral hygiene, plaque was found at virtually all sites after 7 days and the number of sites with gingivitis increased simultaneously. A reduction in gingival inflammation occurred subsequent to plaque removal. During phases of both plaque accumulation and thorough oral hygiene, sites were found to convert from non-inflamed to inflamed status concurrently, as in the reverse direction. No association between plaque and gingivitis was revealed. The gingival status of a single site was a poor predictor of its status on the subsequent occasion. The proportion of inflamed sites converting to non-inflamed status was greater than the proportion of non-inflamed sites converting to inflamed status at any time. The estimated incidence rate remained fairly constant during both the plaque accumulation phase and the oral hygiene phase, whereas the estimated recovery rate was considerable lower during the plaque accumulation phase compared to oral hygiene phase. The clinical appearance is the outcome of the dynamics between these rates. The steady-state prevalences derived from the estimated "incidence" and "recovery" rates were quite similar to the actual findings after 14 d of plaque accumulation and the subsequent 10 d of thorough oral hygiene.     

The effects of a new mouthrinse containing chlorhexidine,cetylpyridinium chloride and zinc lactate on the microflora of oral halitosis patients: a dual-centre,double-blind placebo-controlled study

AIM: This study evaluated the microbial effects of a newly formulated mouthwash (Halita) on oral halitosis patients. METHODS: Forty subjects were included in this dual-centre, double-blind, placebo-controlled parallel study. Inclusion and exclusion criteria were used to select patients. At baseline and at 2 weeks post-treatment, full-mouth organoleptic odor scores, level of volatile sulphur compounds (VSC) and the Winkel Tongue Coating Index were recorded. Standardized samples of tongue coating, saliva and subgingival plaque were microbiologically investigated. Participants were randomly assigned to the test or placebo groups. RESULTS: High prevalences were observed for Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas gingivalis in tongue coating, saliva and subgingival plaque samples. A significant positive correlation between baseline total counts of P. gingivalis in saliva samples and organoleptic and VSC scores was found. Two weeks post-treatment there was a reduction in total anaerobic counts in all samples in the test group. A significant positive correlation was observed between the reduction in total counts in saliva samples and the reduction in organoleptic scores in the test group. Significant reductions in total counts and proportions of F. nucleatum and total counts of P. intermedia in tongue coating samples were observed in the test group. CONCLUSIONS: The test mouthwash demonstrated efficacy in reducing the microbiological parameters in three oral niches in moderate to severe halitosis patients without periodontitis, and this was correlated with the improvements in organoleptic and VSC scores but not with the tongue coating scores.     

Porphyromonas gingivalis platelet aggregation activity: outer membrane vesicles are potent activators of murine platelets

Recent evidence has established an association between chronic periodontitis and cardiovascular disease. Periodontitis is a chronic inflammatory disease caused by a small group of gram-negative bacteria, of which Porphyromonas gingivalis is considered an important causative agent. It has been proposed that dental plaque bacteria and their products can disseminate into the bloodstream from the site of infection and promote thromboembolic events associated with atherosclerosis and myocardial infarction. In this regard, Streptococcus sanguis and P. gingivalis have been shown to induce platelet aggregation in vitro. Here we report that P. gingivalis was able to induce platelet aggregation, and that oral strains of Actinobaillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Fusobacterium nucleatum, Prevotella intermedia and Trepenoma denticola failed to aggregate platelets when tested for platelet aggregation activity under similar conditions. Additionally, we show that vesicles (outer membrane evaginations that are shed into the environment by the bacteria) of P. gingivalis are potent inducers of mouse platelet aggregation in vitro. In summary, our data show that i) initial adherence of the bacterium to platelet may be facilitated by P. gingivalis fimbriae and ii) P. gingivalis vesicles possess platelet aggregation-inducing activity.     

Dipeptide utilization by the periodontal pathogens Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum

Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum, which can frequently be isolated from periodontal pockets, preferentially utilize proteins and peptides as growth substrates. In this study, we determined the size of peptide that is preferentially utilized as a source of energy and material for cell growth by P. gingivalis, P. intermedia, P. nigrescens and F. nucleatum using various sizes of poly amino acids consisting of two to approximately 100 molecules of aspartate or glutamate. Resting cells of P. gingivalis, P. intermedia and P. nigrescens utilized aspartylaspartate, while cells of P. gingivalis and F. nucleatum utilized glutamylglutamate. The addition of aspartylaspartate to the culture medium increased the growth of P. gingivalis, P. intermedia and P. nigrescens, while the addition of glutamylglutamate promoted the growth of P. gingivalis and F. nucleatum. These results clearly indicate that dipeptides such as aspartylaspartate and glutamylglutamate can be utilized as growth substrates for P. gingivalis, P. intermedia, P. nigrescens and F. nucleatum.     

Periodontal bacteria in adult twins

BACKGROUND: Both environmental and genetic factors are known to influence clinical measures of periodontal disease. The purpose of this study was to determine whether genetic factors similarly influence the presence of specific periodontal bacteria in subgingival plaque. METHODS: Reared-together and reared-apart monozygous (MZ) and dizygous (DZ) adult twins were examined clinically. Demographic and behavioral information was obtained from each subject by questionnaire. Subgingival plaque samples were obtained from the index teeth, and the presence of P. intermedia, P. gingivalis, A. actinomycetemcomitans, E. corrodens, and F. nucleatum was determined using an immunoassay. RESULTS: Microbiological and clinical data were available for 169 twin pairs. The subject-based prevalences of the bacteria in the twin groups ranged from 11% for Porphyromonas gingivalis to 40% for F. nucleatum. For all species examined, the concordance rates were not significantly different (P > 0.05) between MZ and DZ twin groups. These findings were apparent despite similar smoking histories, self-reported oral hygiene practices, and antibiotic use in the twin groups. Furthermore, MZ twins reared together were not more similar than MZ reared-apart twins with respect to any bacterial species examined. CONCLUSIONS: These findings suggest that in a population with access to routine dental care, any effects that host genes and the early family environment have on the presence of specific bacteria in subgingival plaque are not apparent in adulthood. Most twins with disease in this study had early periodontitis. Results from this study may not necessarily be extrapolated to more advanced disease states.     

Multicenter evaluation of tetracycline fiber therapy. III. Microbiological response

In a multicenter study of the effects of tetracycline (TC) fiber therapy, subgingival plaque samples were tested for 6 probable periodontal pathogens by DNA probe analysis. Levels of Actinobacillus actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas (Bacteroides) gingivalis, Prevotella intermedia (Bacteroides intermedius), and Wolinella recta were quantitatively determined in samples taken at baseline, and immediately after TC fiber removal, control fiber removal, and scaling and root planing. At untreated sites, samples were taken at baseline and 10 d later. Specificity of the DNA probe method was evaluated by testing the hybridization to 83 reference cultures. Interaction of the F. nucleatum probe with Fusobacterium periodonticum, and of the W. recta probe with Wolinella curva were the only cross-hybridizations noted. Species were detected at an average sensitivity of 2.9 x 10(4) organisms per sample. Approximately 70% of sites were initially infected with P. gingivalis and F. nucleatum; 50% with P. intermedia and E. corrodens; infections with W. recta and A. actinomycetemcomitans were less common (36% and 11% respectively). The average numbers of organisms found in the plaque samples were highest for F. nucleatum, P. gingivalis, and P. intermedia (ca. 10(6)). E. corrodens, W. recta, and A. actinomycetemcomitans occurred at 10-fold lower levels. Bacterial numbers and proportions of species in subgingival sites from the five centers did not differ appreciably. Both TC fiber therapy and scaling decreased the number of sites infected with all the monitored species. The bacterial composition at untreated sites and at sites where control fibers were placed was not significantly altered. The percentage reduction of the number of sites with detectable infection varied with each species: from 86% with W. recta to approximately 40% with P. gingivalis. Significant reduction of pocket depth and bleeding occurred at TC fiber-treated sites infected with each of the species. Significant attachment level gain occurred only at sites initially infected with P. gingivalis and treated with TC fibers.     

血链球菌对牙周可疑致病菌体外拮抗作用的研究

目的体外研究血链球菌与牙周可疑致病菌的相互关系,探讨血链球菌全菌细胞、培养上清液对牙周可疑致病菌的拮抗作用。方法分别采用交叉双层培养基法和微量琼脂糖弥散法测定血链球菌全菌细胞和培养上清液对牙龈卟啉单胞菌、中间普雷沃菌、具核梭杆菌的拮抗作用。结果血链球菌全菌细胞均能拮抗这3种牙周可疑致病菌的生长;而其培养上清液无拮抗作用。结论血链球菌在牙周微生态系中起有益菌的作用,同时交叉双层培养基法是一种简便易行的测定血链球菌抑菌活性的方法。     

Use of the Syrian golden hamster for the induction of intraoral abscesses by sutures contaminated with human subgingival plaque

Analysis of normal oral flora in 150 cheek pouches of hamsters ( Mesocricetus auratus ) defined the microbial working environment and demonstrated the absence of human oral black-pigmented bacteria. Silk sutures saturated with Porphyromonas gingivalis, Prevotella intermedia or subgingival plaque were used to close wounds made in hamster's cheek pouches. Abscesses were formed when sutures had solitary P. gingivalis or other bacteria mixed with P. gingivalis or when P. intermedia was mixed with other bacteria besides P. gingivalis. A concentration of black-pigmented bacteria emanating from 3×10⁵ colony-forming units/inoculum was required for abscess formation. Six abscesses (14.3%) were developed in association with the presence of other odontopathic bacteria, primarily Fusobacterium nucleatum and Actinomyces viscosus. The hamster cheek pouch with iatrogenic wounds closed with plaque-impregnated sutures is a novel and effective model to study the pathology of wound infections and virulence of human subgingival organisms.     

Acid-neutralizing activity during amino acid fermentation by Porphyromonas gingivalis,Prevotella intermedia and Fusobacterium nucleatum

Acid-neutralizing activity during amino acid fermentation by washed cells of Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum was studied. When the washed cells of these strains were anaerobically incubated in the presence of aspartylaspartic acid or glutamylglutamic acid for P. gingivalis, aspartic acid for P. intermedia and glutamic acid for F. nucleatum at an initial pH of 5.0 or 5.5, the pH of the incubation mixtures rose toward neutral. F. nucleatum had the highest acid-neutralizing activity, followed by P. intermedia and P. gingivalis. The P. intermedia and F. nucleatum cells were used to measure the amounts of base produced at a fixed pH of 5.0. These cells generated significant amounts of base at pH 5.0 along with the production of organic acids and ammonia from aspartic or glutamic acid. Acid-base balance theoretically calculated from the amounts of consumed substrate and end products implies that the acid-neutralizing activity was derived from the decrease in acidity during the fermentation of amino acid into organic acids and ammonia.     

Experimental gingivitis in young and elderly individuals

Abstract The development of experimental gingivitis was studied in young and elderly humans during a 21-d period of oral hygiene abstention. The state of the gingiva was assessed by the Gingival Index and by measurements of the amount of gingival exudate on filter paper strips placed at the entrance of the gingival sulcus of the lower lateral incisors and cuspids. Soft deposits were assessed by the Plaque Index and by differential counts of microorganisms in gram stained smears of dento-gingival plaque. At the end of the plaque growth period, the patients were given a thorough dental prophylaxis. Gingival condition and plaque were assessed at regular intervals during a subsequent period of controlled oral hygiene. The development of gingivitis during the oral hygiene abstention period was more rapid and more severe in old than in young individuals. Plaque accumulation was greater in the older persons. A definite difference in plaque consistency was also observed. However, microscopic counts of various types of microorganisms did not reveal any differences throughout the period of plaque accumulation. When active oral hygiene was reinstituted, the state of the gingiva rapidly returned to pre-experimental levels in both groups. The findings of this study indicate that with age there is an altered host response to the microorganisms of the plaque.     

Degradation of immunoglobulin G by periodontal bacteria

Several subgingival microorganisms were tested for their ability to utilize human immunoglobulin G (IgG) as a substrate for growth. This was done using a protein-free chemically defined medium, supplemented with IgG. Stimulation of growth was observed for Capnocytophaga ochracea, Porphyromonas asaccharolytica, Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella oralis, Lactobacillus catenaforme and Streptococcus intermedius. Immunoelectrophoresis, sodium dodecyl sulfatepolyacrylamide gel electrophoresis and a protein assay demonstrated that P. intermedia and P. endodontalis completely degraded the protein chains of IgG. Partial breakdown of IgG was observed for P. asaccharolytica and C. ochracea , whereas P. oralis cleaved the IgG heavy chain, yielding Fc and Fab fragments. All these bacteria utilized IgG as a substrate for growth. Binding studies using an enzyme-linked immunosorbent assay, revealed complete loss of in vitro antigen-antibody binding capacity after incubation of specific IgG with P. endodontalis and partial loss of binding with P. intermedia , P. gingivalis, C. ochracea or Fusobacterium nucleatum. Degradation or inactivation of IgG by oral bacteria is thought to be important in the causation of polymicrobial infections.     

牙周可疑致病菌对胶原包被羟磷灰石黏附的体外实验研究

目的比较对牙根面具有黏附能力的具核梭杆菌、牙龈卟啉单胞菌、中间普氏菌和伴放线菌嗜血菌对胶原包被的羟磷灰石实验膜（C- HA）的黏附能力,初步探讨以上牙周可疑致病菌在牙根表面形成菌斑生物膜的能力。方法采用同位素闪烁计数法测定上述4种细菌黏附至C- HA表面的黏附量及黏附率,比较其黏附能力。结果培养相同时间,不论是培养24 h还是培养48 h,4种不同细菌两两比较,具核梭杆菌ATCC 10953和牙龈卟啉单胞菌ATCC 33277对C- HA表面黏附率的差异无统计学意义;中间普氏菌ATCC 25611和伴放线菌嗜血菌ATCC 29523的黏附率之间差异也无统计学意义,但是具核梭杆菌ATCC 10953和牙龈卟啉单胞菌ATCC 33277对C- HA表面的黏附率显著高于中间普氏菌ATCC 25611和伴放线菌嗜血菌ATCC 29523（P<0.001）。同一种细菌,在培养不同时间即培养24 h和48 h,对C- HA表面黏附率的差异均无统计学意义。结论不同的牙周可疑致病菌对胶原包被的羟磷灰石的选择性黏附作用不同,具核梭杆菌和牙龈卟啉单胞菌对胶原有较强的亲和作用,在细菌的局部定植过程和牙周炎的进展和复发中可能发挥重要作用。     

牙周致病菌和致龋菌间生长关系的体外动态观察

目的研究6种代表性牙周致病菌和致龋菌在菌斑生物膜和悬浮液中的消长关系。方法将双菌组（致龋菌＋牙周致病菌）接种于改良恒化器中,连续培养1h、24h、48h和96h,然后取在羟基磷灰石表面形成的生物膜和悬浮液再进行细菌培养。结果与血链球菌混合培养时,菌斑生物膜和悬浮液中牙周致病菌均增多,而血链球菌明显减少（P〈0.05）;具核梭杆菌与变形链球菌培养时,菌斑生物膜和悬浮液中具核梭杆菌明显增多,而变形链球菌减少（P〈0.05）。菌斑生物膜中致龋菌占优势,相应的悬浮液中牙周致病菌96h开始占优势。悬浮液中细菌量波动更明显。结论2类致病菌在菌斑生物膜与相应的悬浮液中的生长是不一致的。2类致病菌之间相互作用也许是决定菌斑生物膜内部生态环境发展方向的主要因素。     

The effect of Octapinol on dento-gingival plaque and development of gingivitis

Octapinol, a compound which in previous studies has been shown to reduce plaque formation in vitro and to reduce gingivitis in vivo in dogs, was studied with regard to its effect on plaque formation and gingivitis in man.
The study was divided in two parts. In the first, 24 dental hygiene students were divided into 4 groups of equal size and starting from a plaque-free base line were treated with 0.1–1.0% w/v aqueous solutions of Octapinol applied daily for 4 days onto the teeth on one side of the jaw while the contralaterial side was treated with a placebo solution. In the second study, 7 students starting from a plaque- and gingivitis-free base line applied a 1.0% solution daily to all teeth for a 3-week period during which time no mechanical oral hygiene was allowed. After a period of resumed oral hygiene another 3-week period of no oral hygiene followed during which a placebo solution was applied in a similar fashion.
In the first study 0.5 and 1.0% concentrations of Octapinol significantly reduced the plaque formation during the 4-day test period while the effect of lower concentrations was less prominent.
In the 3-week experiment using a 1% Octapinol solution only minor development of plaque and gingivitis was noted during the test period while rapid accumulation of plaque and marked gingival inflammation occurred during the control period.     

Amalgam restorations, plaque removal and periodontal health

Abstract. A total of 156 approximal subgingival amalgam overhanging margins were assessed in the buccal segments of 13 patients for plaque accumulation, gingival inflammation, pocket depth and gingival shrinkage. Recordings were made immediately before and 2, 4 and 8 weeks fallowing scaling, removal of overhangs, and oral hygiene instruction. Surfaces with overhangs were compared with control surfaces, which were either intact or contained supragingival amalgams. Initially it was found that gingival inflammation and pocket depth were more extensive adjacent to subgingival amalgam overhangs than to sound teeth or those with supragingivally located amalgams. This appeared to be due to preferential plaque accumulation in relation to subgingival overhangs. For all parameters compared, differences apparent at the baseline had disappeared by the end of the 8-week study period. Contouring of defective subgingival restorations, followed by effective scaling and oral hygiene instruction produced approximately 1 mm of gingival shrinkage, sufficient in most cases to produce clinical gingival health. Of the 156 subgingival fillings 83 (53 % ) became supragingival and 43 (28 %) reached the gingival crest by the end of the 8-week study period.