Subsequent Bacterial Colonization Research Articles

The effect of laser therapy for the treatment of dentin hypersensitivity on surface roughness and bacterial adhesion

The aim of the study was to measure the degree of dentine surface roughness caused by five distinct lasers used to treat dentine hypersensitivity, as well as to evaluate the subsequent bacterial colonization on these irradiated surfaces. Sixty human maxillary premolar teeth without caries or restoration which were extracted for periodontal reasons were used in this study. Five different types of lasers were applied to the root dentin surface. Tested samples were divided into six groups of 10 samples each; control, diode (810 nm), diode (980 nm), Nd: YAG, Er: YAG, and Er, Cr: YSGG laser groups. The arithmetic mean of the surface roughness values (Ra) and the average roughness over a measurement area (Sa) were measured pre- and post-application using any of the laser types. Swab samples were then collected from the dentin surface. Following a 24-hour incubation period at 37 °C, the colony forming units were counted using a stereoscope. The results demonstrated a statistically significant difference in the surface roughness values pre- and post-application (Ra and Sa, respectively) in the Er, Cr: YSGG laser group (p = 0.037,p = 0.007). No significant difference was observed in the other groups (p > 0.05). There was no statistically significant difference in the number of bacterial colonies observed between the test and control groups. Diode and Nd: YAG lasers showed either a decrease or no change in surface roughness; however, the hard tissue lasers (Er: YAG, Er, Cr: YSGG) showed an increase. The Er: YAG and Nd: YAG laser groups exhibited decreased bacterial adhesion compared to the other groups.

Role of the polyamine transporter PotABCD during biofilm formation by Streptococcus pneumoniae.

Streptococcus pneumoniae is a bacterium of great global importance, responsible for more than one million deaths per year. This bacterium is commonly acquired in the first years of life and colonizes the upper respiratory tract asymptomatically by forming biofilms that persist for extended times in the nasopharynx. However, under conditions that alter the bacterial environment, such as viral infections, pneumococci can escape from the biofilm and invade other niches, causing local and systemic disease of varying severity. The polyamine transporter PotABCD is required for optimal survival of the organism in the host. Immunization of mice with recombinant PotD can reduce subsequent bacterial colonization. PotD has also been suggested to be involved in pneumococcal biofilm development. Therefore, in this study we aimed to elucidate the role of PotABCD and polyamines in pneumococcal biofilm formation. First, the formation of biofilms was evaluated in the presence of exogenous polyamines-the substrate transported by PotABCD-added to culture medium. Next, a potABCD-negative strain was used to determine biofilm formation in different model systems using diverse levels of complexity from abiotic surface to cell substrate to in vivo animal models and was compared with its wild-type strain. The results showed that adding more polyamines to the medium stimulated biofilm formation, suggesting a direct correlation between polyamines and biofilm formation. Also, deletion of potABCD operon impaired biofilm formation in all models tested. Interestingly, more differences between wild-type and mutant strains were observed in the more complex model, which emphasizes the significance of employing more physiological models in studying biofilm formation.

Role of traveling microplastics as bacterial carriers based on spatial and temporal dynamics of bacterial communities

Microplastics (MPs) are considered as distinct substrates for bacterial colonization, they can carry bacterial communities to travel around environments. The bacterial communities on traveling MPs prefer to be gradually consistent with those on local MPs that were always in the same environment, and this process of change in the bacterial communities on traveling MPs was called ‘localization’. However, the dynamics of localization process and their influencing factors are still unclear. Therefore, we simulated the MPs migration process along the water flow direction in the estuary. We used quantitative analysis to study the dynamics of bacterial communities on the migrated MPs. We found the localization characteristics depended on the differences between the former and latter environments, as well as the preexisting bacteria. The localization degree was higher when the former and latter environments were similar. In most cases, compared with the first cultivation of pristine MPs, the time for localization was shorter. Moreover, although the entire bacterial communities tended to be localized, the preexisting bacteria on the migrated MPs had selective effects on subsequent bacterial colonization. Furthermore, the preexisting bacteria on MPs could set up the connections with the bacteria that existed at the latter site, and the stability of the entire bacterial communities on the migrated MPs increased with time. Overall, our findings indicated that the localization characteristics of bacterial communities on traveling MPs were related to the precultured time and environmental differences, which were helpful to understand the colonized bacteria transportation and MPs ecological effects.

Effects of reducing excess dental adhesive on bacterial adhesion in the bracket periphery

ObjectivesWhite spot lesions are one of the most common side effects of orthodontic therapy with a multibracket appliance and may indicate a preliminary stage of caries, also known as initial caries. Several approaches may be utilized to prevent these lesions, such as reducing bacterial adhesion in the area surrounding the bracket. This bacterial colonization can be adversely affected by a number of local characteristics. In this context, the effects of excess dental adhesive in the bracket periphery were investigated by comparing a conventional bracket system with the APC flash-free bracket system.Materials and methodsBoth bracket systems were applied to 24 extracted human premolars, and bacterial adhesion with Streptoccocus sobrinus (S. sobrinus) was performed for 24 h, 48 h, 7 d, and 14 d. After incubation, bacterial colonization was examined in specific areas by electron microscopy.ResultsOverall, significantly fewer bacterial colonies were found in the adhesive area around the APC flash-free brackets (n = 507 ± 13 bacteria) than the conventionally bonded bracket systems (n = 850 ± 56 bacteria). This is a significant difference (**p = 0.004). However, APC flash-free brackets tend to create marginal gaps with more bacterial adhesion in this area than conventional bracket systems (n = 265 ± 31 bacteria). This bacterial accumulation in the marginal-gap area is also significant (*p = 0.029).ConclusionA smooth adhesive surface with minimal adhesive excess is beneficial for reducing bacterial adhesion but also poses a risk of marginal gap formation with subsequent bacterial colonization, which can potentially trigger carious lesions.Clinical relevanceTo reduce bacterial adhesion, the APC flash-free bracket adhesive system with low adhesive excess might be beneficial.APC flash-free brackets reduce the bacterial colonization in the bracket environment.A lower number of bacteria can minimize white spot lesions in the bracket environment.APC flash-free brackets tend to form marginal gaps between the bracket adhesive and the tooth.

Heterotypic Influenza Infections Mitigate Susceptibility to Secondary Bacterial Infection.

Influenza-associated bacterial superinfections have devastating impacts on the lung and can result in increased risk of mortality. New strains of influenza circulate throughout the population yearly, promoting the establishment of immune memory. Nearly all individuals have some degree of influenza memory before adulthood. Due to this, we sought to understand the role of immune memory during bacterial superinfections. An influenza heterotypic immunity model was established using influenza A/Puerto Rico/8/34 and influenza A/X31. We report in this article that influenza-experienced mice are more resistant to secondary bacterial infection with methicillin-resistant Staphylococcus aureus as determined by wasting, bacterial burden, pulmonary inflammation, and lung leak, despite significant ongoing lung remodeling. Multidimensional flow cytometry and lung transcriptomics revealed significant alterations in the lung environment in influenza-experienced mice compared with naive animals. These include changes in the lung monocyte and T cell compartments, characterized by increased expansion of influenza tetramer-specific CD8+ T cells. The protection that was seen in the memory-experienced mouse model is associated with the reduction in inflammatory mechanisms, making the lung less susceptible to damage and subsequent bacterial colonization. These findings provide insight into how influenza heterotypic immunity reshapes the lung environment and the immune response to a rechallenge event, which is highly relevant to the context of human infection.

Facile synthesis and coating of aqueous antifouling polymers for inhibiting pathogenic bacterial adhesion on medical devices

Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. Thus, there is an urgent need for novel modification of antibiofilm surfaces on polymeric medical devices to inhibit pathogenic bacterial adhesion. Herein, we describe the development of water-soluble, antifouling polymers (APs) containing benzene moieties capable of anchoring to hydrophobic surfaces and hydrophilic poly (ethylene) glycol and carboxyl groups to inhibit pathogenic bacterial adhesion on polymeric medical devices. We found that the optimized APs could be facilely and controllably synthesized on and modify the surfaces of commercial hydrophobic substrates in aqueous solution, with the resulting polymer-coated surfaces capable of efficiently preventing pathogenic bacterial adhesion and subsequent bacterial colonization as precursors to biofilm formation. These results suggest the potential efficacy of the developed and optimized polymers for use as an antibiofilm platform to inhibit healthcare-associated infections on various polymer-based medical devices.

Smart, Photothermally Activated, Antibacterial Surfaces with Thermally Triggered Bacteria-Releasing Properties.

The development of effective antibacterial surfaces to prevent the attachment of pathogenic bacteria and subsequent bacterial colonization and biofilm formation is critically important for medical devices and public hygiene products. In the work reported herein, a smart antibacterial hybrid film based on tannic acid/Fe3+ ion (TA/Fe) complex and poly(N-isopropylacrylamide) (PNIPAAm) is deposited on diverse substrates. This surface is shown to have bacteria-killing and bacteria-releasing properties based on, respectively, near-infrared photothermal activation and subsequent cooling. The TA/Fe complex has three roles in this system: (i) as a universal adhesive "anchor" for surface modification, (ii) as a high-efficiency photothermal agent for ablation of attached bacteria (including multidrug resistant bacteria), and (iii) as a robust linker for immobilization of NH2-terminated PNIPAAm via either Michael addition or Schiff base formation. Moreover, because of the thermoresponsive properties of the immobilized PNIPAAm, almost all of the killed bacteria and other debris can be removed from the surface simply by lowering the temperature. It is shown that this hybrid film can maintain good antibacterial performance after being used for multiple "kill-and-release" cycles and can be applied to various substrates regardless of surface chemistry or topography, thus providing a broadly applicable, simple, and reliable solution to the problems associated with surface-attached bacteria in various healthcare applications.

Impact of the springtail's cuticle nanotopography on bioadhesion and biofilm formation in vitro and in the oral cavity.

Springtails (Collembola) have a nanostructured cuticle. To evaluate and to understand anti-biofouling properties of springtail cuticles’ morphology under different conditions, springtails, shed cuticles and cuticle replicates were studied after incubation with protein solutions and bacterial cultures using common in vitro models. In a second step, they were exposed to human oral environment in situ in order to explore potential application in dentistry. In vitro, the cuticular structures were found to resist wetting by albumin solutions for up to 3 h and colonization by Staphylococcus epidermidis was inhibited. When exposed in the oral cavity, initial pellicle formation was of high heterogeneity: parts of the surface were coated by adsorbed proteins, others remained uncoated but exhibited locally attached, ‘bridging’, proteinaceous membranes spanning across cavities of the cuticle surface; this unique phenomenon was observed for the first time. Also the degree of bacterial colonization varied considerably. In conclusion, the springtail cuticle partially modulates bioadhesion in the oral cavity in a unique and specific manner, but it has no universal effect. Especially after longer exposure, the nanotextured surface of springtails is masked by the pellicle, resulting in subsequent bacterial colonization, and, thus, cannot effectively avoid bioadhesion in the oral cavity comprehensively. Nevertheless, the observed phenomena offer valuable information and new perspectives for the development of antifouling surfaces applicable in the oral cavity.

Cesarean Delivery and Neonatal Intestinal Colonization

Research Article| October 01 2016 Cesarean Delivery and Neonatal Intestinal Colonization AAP Grand Rounds (2016) 36 (4): 47. https://doi.org/10.1542/gr.36-4-47 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Cesarean Delivery and Neonatal Intestinal Colonization. AAP Grand Rounds October 2016; 36 (4): 47. https://doi.org/10.1542/gr.36-4-47 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: cesarean section, intestines, microbial colonization, newborn Source: Stokholm J, Thorsen J, Chawer BL, et al. Cesarean section changes neonatal gut colonization. J Allergy Clin Immunol. 2016; 138(3): 881– 889.e2; doi: https://doi.org/10.1016/j.jaci.2016.01.028Google Scholar Investigators from multiple institutions in Denmark conducted a prospective study to identify the relationship between route of delivery and subsequent bacterial colonization of the gastrointestinal tract and the airway in the first 12 months of life. Study participants included mothers and infants who had been enrolled in the Copenhagen Prospective Studies on Asthma, a cohort study of pregnant Danish women and their offspring. For the study, delivery route was categorized as vaginal, emergency cesarean (failed trial of labor), or elective cesarean (membranes ruptured at delivery). Fecal samples were collected and cultured on study children at 1 week, 1 month, and 1 year of life; hypopharyngeal samples were collected at 1 week, 1 month, and 3 months of life. Demographic information collected included maternal age, household income, maternal asthma, maternal smoking during pregnancy, pregnancy complications, the use of intrapartum antibiotics, older children in the home, and duration of breastfeeding. Rates of positive fecal and airway cultures for individual bacteria were compared among children born vaginally or by cesarean delivery. Of the 700 children in the cohort, 549 (78%) were born vaginally, 85 (12%) by emergency cesarean, and 66 (9%) by elective cesarean. All mothers who had cesarean delivery received intrapartum antibiotics compared to 13% of those who delivered vaginally. Fecal and airway samples were obtained on over 90% of enrolled newborns at most time points. The investigators found that at 1 week of life, intestinal colonization with Citrobacter freundii, Clostridium species, Enterobacter cloacae, Enterococcus faecalis, Klebsiella species, and Staphylococcus aureus were significantly associated with cesarean delivery (for either reason), and colonization with E. coli was significantly associated with vaginal delivery. These associations declined over time and disappeared by 1 year of life. No associations were found between route of delivery and airway colonization. The authors conclude that neonates delivered by cesarean section show a pattern of bacterial colonization in the first week of life that differs from that of babies delivered vaginally. They speculate that these differences may play a role in the development of immunemediated disease, such as asthma and allergy, later in life. Dr. Springer has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device. There can be no doubt that while life-saving for some newborns with intrapartum obstetric complications, cesarean delivery is associated with higher incidence of postnatal complications for both mother1–3 and infant.2–5 In the United States, approximately 32% of all deliveries are via cesarean,2 although less than 15% are medically indicated.5 Recently, efforts have been undertaken to reduce the number of cesarean deliveries that are not medically indicated, both from a professional5 as well as economic perspective.6 The authors of the... You do not currently have access to this content.

Predictors of Chronic Lung Allograft Dysfunction (CLAD) Following Respiratory Viral Infection (RVI)

Purpose RVI increases the risk of chronic graft dysfunction and death in lung transplant (LTx) recipients. We examined the features of RVI in LTx patients and their relationship with graft dysfunction at 1 and 2 years post-RVI. Methods and Materials We retrospectively analyzed demographic, clinical (symptoms, hospitalization, hypoxia at the time of RVI), microbiological (viral type, coexisting bacteria/fungus, subsequent bacterial/fungal colonization in the first year post-RVI) and radiographic characteristics of RVI in 49 LTx recipients. RVI was diagnosed by bronchoscopy and/or nasopharyngeal swab. Pulmonary function data at five time points was collected: peak, pre-infection, at time of RVI and at 1 and 2 years post-RVI. A decrease of ≥10% in either FEV1 or FVC compared to stable pre-infection values was deemed significant. We performed univariate and multivariate analyses to identify predictors of graft dysfunction at 1 and 2 years post-RVI. Results Graft dysfunction was noted in 10/49 (20.4%) recipients at 1 year post-RVI and 9/35 (25.7%) at 2 years. Isolated FEV1 loss occurred in 6/10 patients at 1 year post-RVI and 3/9 patients at 2 years. The remaining LTx recipients with graft dysfunction had FVC loss with or without associated FEV1 decline. Hypoxia at the time of RVI, Influenza A, and subsequent bacterial colonization in the year post-RVI predicted graft dysfunction at 1 year in univariate analysis. In multivariate analysis, only subsequent bacterial colonization remained a predictor of graft dysfunction (p=0.009). At 2 years post-RVI, only coexistence of bacteria at the time of RVI was associated with graft dysfunction in univariate and multivariate analysis (p=0.029). Conclusions CLAD occurs in an important number of LTx recipients following RVI, with changes suggestive of both obstructive and restrictive physiology. Bacterial colonization post-RVI as well as the presence of bacteria at the time of RVI appear to affect graft outcome at 1 and 2 years respectively. This suggests important interactions within the microbiome of the graft.

Expert opinion and review article: The timing of comedone extraction in the treatment of premenstrual acne – a proposed therapeutic approach

The face is the most exposed part of our body, and deterioration of facial appearance, through disease or ageing, causes psychological distress. Acne lesions and subsequent pigmentation changes contribute to the unevenness of skin colour that is detrimental to facial attractiveness and leads to rejection and stigmatization in our society. The purpose of this review is to look at the root causes of premenstrual acne and, for the first time ever, propose that the specific timing of treatment can, at least in part, resolve the acne lesions. We postulate that it is the timing of the manual extraction that matters in resolving premenstrual acne and that the effectiveness of this therapy could be improved. Based on the reviewed evidence, we propose that it is important to remove the comedones at the time of ovulation, prior to the reduction of the size of the sebaceous orifice and epidermal barrier function, to counteract the onset of increased sebum production, prevent blockage of the pores and subsequent bacterial colonization and inflammation. If performed successfully, the extraction may contribute to a reduction in inflamed acne lesions and thus benefit women by increasing their facial attractiveness, well-being, social function and thereby decrease psychological stress.

Escherichia coliO157:H7 Colonization in Cattle following Systemic and Mucosal Immunization with Purified H7 Flagellin

Escherichia coli O157:H7 is an important pathogen of humans. Cattle are most frequently identified as the primary source of infection, and therefore, reduction in E. coli O157:H7 prevalence in cattle by vaccination represents an attractive strategy for reducing the incidence of human disease. H7 flagella have been implicated in intestinal-epithelial colonization of E. coli O157:H7 and may represent a useful target for vaccination. In this study, calves were immunized either systemically with H7 flagellin by intramuscular injection or mucosally via the rectum with either H7 or H7 incorporated into poly(DL-lactide-co-glycolide) microparticles (PLG:H7). Systemic immunization resulted in high levels of flagellin-specific immunoglobulin G (IgG) and IgA in both serum and nasal secretions and detectable levels of both antibody isotypes in rectal secretions. Rectal administration of flagellin resulted in levels of rectal IgA similar to those by the intramuscular route but failed to induce any other antibody response, whereas rectal immunization with PLG:H7 failed to induce any H7-specific antibodies. Following subsequent oral challenge with E. coli O157:H7, reduced colonization rates and delayed peak bacterial shedding were observed in the intramuscularly immunized group compared to nonvaccinated calves, but no reduction in total bacterial shedding occurred. Rectal immunization with either H7 or PLG:H7 had no effect on subsequent bacterial colonization or shedding. Furthermore, purified H7-specific IgA and IgG from intramuscularly immunized calves were shown to reduce intestinal-epithelial binding in vitro. These results indicate that H7 flagellin may be a useful component in a systemic vaccine to reduce E. coli O157:H7 colonization in cattle.

Bordetella bronchiseptica Modulates Macrophage Phenotype Leading to the Inhibition of CD4+ T Cell Proliferation and the Initiation of a Th17 Immune Response

Bordetella bronchiseptica is a Gram-negative bacterium equipped with several colonization factors that allow it to establish a persistent infection of the murine respiratory tract. Previous studies indicate that B. bronchiseptica adenylate cyclase toxin (ACT) and the type III secretion system (TTSS) synergize to drive dendritic cells into an altered phenotype to down-regulate the host immune response. In this study, we examined the effects of B. bronchiseptica ACT and TTSS on murine bone marrow-derived macrophages. We demonstrate that ACT and TTSS are required for the inhibition of Ag-driven CD4+ T cell proliferation by bacteria-infected macrophages. We identify PGE2 as the mediator of this inhibition, and we show that ACT and the TTSS synergize to increase macrophage production of PGE2. We further demonstrate that B. bronchiseptica can modulate normal macrophage function and drive the immune response toward a Th17 phenotype classified by the significant production of IL-17. In this study, we show that B. bronchiseptica-infected macrophages can induce IL-17 production from naive CD4+ splenocytes, and that lung tissues from B. bronchiseptica-infected mice exhibit a strong Th17 immune response. ACT inhibited surface expression of CD40 and CD86, suppressed TNF-alpha production, and up-regulated IL-6 production. TTSS also synergized with ACT to up-regulate IL-10 and PGE2 secretion. These findings indicate that persistent colonization by B. bronchiseptica may rely on the ability of the bacteria to differentially modulate both macrophage and dendritic cell function leading to an altered adaptive immune response and subsequent bacterial colonization.

The GacA global regulator of Vibrio fischeri is required for normal host tissue responses that limit subsequent bacterial colonization

Harmful and beneficial bacterium-host interactions induce similar host-tissue changes that lead to contrasting outcomes of association. A life-long association between Vibrio fischeri and the light organ of its host Euprymna scolopes begins when the squid collects bacteria from the surrounding seawater using mucus secreted from ciliated epithelial appendages. Following colonization, the bacterium causes changes in host tissue including cessation of mucus shedding, and apoptosis and regression of the appendages that may limit additional bacterial interactions. We evaluated whether delivery of morphogenic signals is influenced by GacA, a virulence regulator in pathogens, which also influences squid-colonization by V. fischeri. Low-level colonization by a GacA mutant led to regression of the ciliated appendages. However, the GacA mutant did not induce cessation of mucus shedding, nor did it trigger apoptosis in the appendages, a phenotype that normally correlates with their regression. Because apoptosis is triggered by lipopolysaccharide, we examined the GacA mutant and determined that it had an altered lipopolysaccharide profile as well as an increased sensitivity to detergents. GacA-mutant-colonized animals were highly susceptible to invasion by secondary colonizers, suggesting that the GacA mutant's inability to signal the full programme of light-organ responses permitted the prolonged recruitment of additional symbionts.

Diagnosing, managing, and preventing salivary gland disorders.

Salivary function provides host protection, assists in the initiation of food and fluid intake, and enables communication through speech. Without adequate salivary output, oral and pharyngeal health declines along with a person’s quality of life. The complaint of a dry mouth (xerostomia) and the objective finding of salivary dysfunction are common occurrences in older individuals, producing transient and permanent oral and systemic problems. Salivary dysfunction, however, is not a normal consequence of growing older, and is due to systemic diseases, medications, and head and neck radiotherapy. Diagnosis of salivary disorders begins with a careful medical history, head, and neck examination. While complaints of xerostomia may be indicative of a salivary gland disorder, salivary diseases can present without symptoms. Therefore, routine examination of salivary function must be part of any head, neck, and oral examination. Therapies are designed to prevent the development of oral and pharyngeal sequelae of salivary hypofunction. Current xerostomia-based treatments include replacement therapies and gustatory, masticatory, and pharmacological stimulants. Healthcare professionals can play a vital role in identifying patients at risk for developing salivary dysfunction, and should provide appropriate preventative and interventive techniques that will help preserve a person’s health, function, and quality of life.

Acute acalculous cholecystitis in the critically ill patient

Nine cases of acute acalculous cholecystitis were diagnosed in the surgical intensive care unit at Hartford Hospital during a 2 year period after abdominal, cardiovascular, and traumatic surgery. A tender mass in the right upper quadrant was suggestive but not diagnostic of the condition. Hyperamylasemia was seen in all patients. Ultrasonography is the most useful diagnostic tool; serial studies reveal progressive gallbladder dilatation and edema. Tube cholecystostomy was used in five patients and cholecystectomy in four. Cholecystostomy led to resolution of the inflammatory process in all five patients. Cholecystectomy should be reserved for those patients with extensive gallbladder necrosis. Six of the nine patients in the series died, all from multiple systems failure with concomitant sepsis. Hypotension is probably central to the development of acute acalculous cholecystitis. In the face of elevated intraluminal gallbladder pressure caused by ampullary edema and increased bile viscosity, hypotension may result in mucosal ischemia and necrosis with subsequent bacterial colonization. Acute acalculous cholecystitis represents another organ failure in critically ill patients who are experiencing progressive failure of multiple organ systems. An aggressive approach to the manifestations of organ failure, including acalculous cholecystitis, must be employed.

Clinical adhesiveness of the tooth surface.

The clinical adhesiveness of tooth structure was determined for 43 individuals using intraoral contact angle measurements. There were no statistically significant differences in the critical surface tensions of wetting between groups of males and females nor between the three age groups tested. There was a statistically significant difference between individuals. The critical surface tensions for all the tooth surfaces measured were in the bioadhesive range of 32--50 dynes/cm. The formation of an organic film, pellicle, on the surfaces of teeth brings groups of different ages and sex to a common state of bioadhesiveness, allowing for the subsequent bacterial colonization and plaque formation as a clinical consequence.