Dental Plaque and Calculus Formation

Which type of bacteria mainly colonize the oral cavity of newborns within hours after birth?

What does the oral microbiota of newborns closely resemble in terms of the mother’s microbiota?

When can anaerobic bacteria be detected in the infant’s edentulous mouth?

What happens to the number of oral bacteria in newborns as a result of exposure to external environmental microbial sources?

In what type of delivery does the oral microbiota of newborns resemble the mother’s skin microbiota?

What is the initial state of the oral cavity at birth according to the text?

Which species are among the first colonizers of the oral cavity of newborn infants?

What is the estimated number of different species capable of colonizing the adult mouth?

In what context can disease occur due to the commensal microbiota?

Which bacteria has been associated with aggressive periodontitis?

What is crucial for the induction of infectious diseases such as gingivitis or periodontitis?

Where are areas of gingival inflammation characterized by an increased number of adhering bacteria?

What is the primary composition of dental plaque?

What distinguishes supragingival plaque from subgingival plaque?

Which microorganisms are found in dental plaque, apart from bacteria?

What characterizes the subgingival region environment compared to the supragingival region?

Which microorganisms dominate the tooth-associated cervical plaque that adheres to the root cementum?

What do studies indicate about plaque associated with crevicular epithelial cells?

What is the primary colonizing bacteria adhered to the tooth surface known as?

What is the process of plaque formation divided into?

What is the acquired pellicle on tooth surfaces composed of?

Which proteins retain enzymatic activity when incorporated into the pellicle?

What did Walker and coworkers report about dental plaque samples and in vitro biofilms?

What occurs in the second stage of initial adhesion to the tooth surface?

Which of the following is true about Prevotella intermedia and other black-pigmented Prevotella spp.?

In nature, bacteria struggle to obtain sufficient nutrients due to:

Where are the densest bacterial populations located in aquatic ecosystems?

What makes the oral cavity somewhat unique in terms of microbial colonization?

Biofilm bacteria are often up to 1000 times more resistant to antimicrobial agents than their planktonic counterparts due to:

The intercellular matrix of dental plaque confers a specialized environment that distinguishes the bacteria within the biofilm from those that are free-floating. This state is known as:

Which physicochemical forces are mediating adhesin-receptor interactions in the context of bacterial binding to surfaces?

What is the estimated range of ligand-receptor interactions required to attain irreversible binding of a bacterial cell to the pellicle?

Which proteins in the acquired pellicle can act as receptors for streptococci?

What is the main component of the salivary pellicle that mediates binding with oral streptococci?

What is the distinctive feature of coaggregation compared to agglutination?

What determines strong cell-cell binding in coadhesion?

What is the distinctive characteristic of lactose-inhibitable coaggregations?

What is the role of early colonizers in plaque formation?

What distinguishes coadhesion from bacterial binding to surfaces?

Which forces prevent bacterial cells from getting closer than approximately 10 nm to a surface?

What is the estimated number of different species capable of colonizing the adult mouth?

What is the distinctive feature of coaggregation compared to agglutination?

What is the primary composition of dental plaque?

What determines strong cell-cell binding in coadhesion?

What makes the oral cavity somewhat unique in terms of microbial colonization?

What occurs in the second stage of initial adhesion to the tooth surface?

What is the process of plaque formation divided into?

What characterizes the subgingival region environment compared to the supragingival region?

What occurs in the second stage of initial adhesion to the tooth surface?

What is the primary composition of dental plaque?

What happens to the number of oral bacteria in newborns as a result of exposure to external environmental microbial sources?

What does the oral microbiota of newborns closely resemble in terms of the mother’s microbiota?

What is the estimated number of distinct microbial phylotypes present as natural inhabitants of dental plaque?

What type of bacteria dominates in the outer surface of the mature plaque mass?

What is the primary composition of subgingival plaque in terms of microorganisms?

What distinguishes dental plaque from materia alba?

What environmental parameter differs between the subgingival and supragingival regions?

What is the distinguishing factor of the plaque associated with crevicular epithelial cells?

What distinguishes dental plaque biofilm from other biofilms?

Why are biofilm bacteria often up to 1000 times more resistant to antimicrobial agents than their planktonic counterparts?

What are the primary inorganic components of subgingival plaque, and how does their presence lead to calculus formation?

Explain the role of the biofilm matrix in dental plaque.

What distinguishes the human oral cavity in terms of microbial colonization?

Why is dental plaque considered one of the most highly studied biofilm systems?

What are the primary phases involved in the process of plaque formation?

What is the composition of the acquired pellicle on tooth surfaces?

What is the mechanism by which primary colonizing bacteria are transported to the tooth surface?

What is the distinctive feature of the salivary pellicle in terms of its association with dental plaque samples?

Which types of microorganisms bind with streptococci and/or actinomyces in the context of coaggregation?

What is the impact of incorporating proteins into the pellicle in terms of the physiology and metabolism of adhering bacterial cells?

What is the estimated range of ligand-receptor interactions required to attain essentially irreversible binding of a bacterial cell to the pellicle?

What is the primary role of early colonizers in plaque formation?

What are the proteins in the acquired pellicle that can act as receptors for streptococci?

What distinguishes coaggregation from agglutination in the context of bacterial binding?

What physicochemical forces mediate adhesin-receptor interactions in the context of bacterial binding to surfaces?

What characterizes the subgingival region environment compared to the supragingival region?

What is the distinctive characteristic of lactose-inhibitable coaggregations?

What is the distinctive feature of coadhesion compared to bacterial binding to surfaces?

What makes the oral cavity somewhat unique in terms of microbial colonization?

What is the main component of the salivary pellicle that mediates binding with oral streptococci?

One gram of plaque (wet weight) contains approximately ______ bacteria

The number of bacteria in supragingival plaque on a single tooth surface can exceed ______ cells

In a periodontal pocket, counts can range from bacteria in a healthy crevice to more than ______ bacteria in a deep pocket

More than ______ distinct microbial phylotypes can be present as natural inhabitants of dental plaque

Non-bacterial microorganisms that are found in plaque include archaea,yeasts, protozoa, and ______

Supragingival plaque is found at or above the gingival margin; when in direct contact with the gingival margin, it is referred to as ______ plaque

The colonization of the oral cavity starts close to the time of ______

Within hours after ______, the sterile oral cavity will be colonized by low numbers of mainly facultative and aerobic bacteria.

From the second day, ______ bacteria can be detected in the infant’s edentulous mouth.

The number of oral bacteria increases gradually as a result of exposure to external environmental ______ sources.

The oral microbiota of newborns closely resembles the mother’s vaginal microbiota or, for newborns delivered by cesarean section, the mother’s ______ microbiota.

The intercellular matrix of dental plaque confers a specialized environment that distinguishes the bacteria within the biofilm from those that are ______. This state is known as:

The apical part of the subgingival plaque is more dominated by spirochetes, cocci, and ______, whereas in the coronal part more filaments are observed.

The process of plaque formation can be divided into several phases: (1) the formation of the pellicle on the tooth surface; (2) the initial adhesion/attachment of ______; and (3) colonization/plaque maturation.

The pellicle on tooth surfaces consists of more than peptides, proteins, and glycoproteins, including keratins, mucins, proline-rich proteins, phosphoproteins (e.g., statherin), histidine-rich proteins, and other molecules that can function as adhesion sites (receptors) for ______.

The primary colonizing bacteria adhered to the tooth surface provide new receptors for attachment by other bacteria as part of a process known as ______.

The first stage involves the initial transport of the bacterium to the tooth surface. Random contacts may occur, for example, through Brownian motion (average displacement, 40 μm/hour), through sedimentation of microorganisms, through liquid flow, or through active bacterial movement (chemotactic activity). It should be noted, however, that relatively few oral bacteria are ______.

The second stage results in an initial reversible adhesion of the ______. This is initiated when the bacterial cell comes into close proximity to the surface (separation distance, ≈50 nm).

The human body provides several interfaces that support microbial populations, of which the most important in healthy individuals are the skin, gut, mouth, and female urogenital tract. As mentioned previously, the oral cavity is somewhat unique in this regard, because it provides hard, nonshedding surfaces (teeth) that are accessible for microbial colonization. Biofilm bacteria are often up to ______ times more resistant to antimicrobial agents than their planktonic counterparts. Bacteria that grow in multispecies biofilms interact closely with neighboring cells. Sometimes these interactions are mutually beneficial, as is the case when one organism removes another’s waste products and uses them as an energy source. In other instances, bacteria compete with their neighbors by secreting antibacterial molecules such as inhibitory peptides (bacteriocins) or hydrogen peroxide ($H_2O_2$). In addition, the biofilm mode of growth facilitates cell–cell signaling and deoxyribonucleic acid (DNA) exchange between bacteria. It is clear that microbial ecology within biofilm communities is highly complex and that, in many cases, knowledge is only emerging at this point.

The architecture of a dental plaque biofilm has many features in common with other biofilms. It is heterogeneous in structure, with clear evidence of open fluid-filled channels running through the plaque mass. Nutrients make contact with the sessile (attached) microcolonies by diffusion from the water channels to the microcolony rather than from the matrix. The bacteria exist and proliferate within the intercellular matrix through which the channels run. The matrix confers a specialized environment that distinguishes the bacteria that exist within the biofilm from those that are free-floating; this is the so-called “______ state” in solutions such as saliva or crevicular fluid. The biofilm matrix functions as a barrier. Substances produced by bacteria within the biofilm are retained and concentrated, which fosters metabolic interactions among different bacteria. The intercellular matrix consists of organic and inorganic materials derived from saliva, gingival crevicular fluid, and bacterial products. The inorganic components of plaque are predominantly calcium and phosphorus, with trace amounts of other minerals such as sodium, potassium, and fluoride.

The source of inorganic constituents of supragingival plaque is primarily saliva. As the mineral content increases, the plaque mass becomes ______ to form calculus. Calculus is frequently found in areas of the dentition adjacent to salivary ducts (e.g., the lingual surface of the mandibular incisors and canines, the buccal surface of the maxillary first molars), which reflects the high concentration of minerals available from saliva in those regions. The inorganic components of subgingival plaque are derived from crevicular fluid (a serum transudate). The calcification of subgingival plaque also results in calculus formation (Figure 8-9). Subgingival calculus is typically dark green or dark brown, which probably reflects the presence of blood products that are associated with subgingival hemorrhage. The importance of these biofilms for oral diseases, such as dental caries and periodontitis—together with the relative ease with which tooth surface biofilms can be accessed—has led to dental plaque becoming one of the most highly studied biofilm systems.

The tough ______ matrix makes it impossible to remove plaque by rinsing or with the use of sprays. Plaque can thus be differentiated from other deposits that may be found on the tooth surface, such as materia alba and calculus.

It is anticipated that, by understanding the ______ involved in the accumulation of dental plaque and the transition from health to disease, it will be possible to improve our control over these processes and to further restrict plaque-associated oral diseases.

The intercellular matrix of dental plaque confers a specialized environment that distinguishes the bacteria within the biofilm from those that are free-floating. This state is known as:

At distances of approximately 10 nm from the surface, bacterial cells are reversibly bound. It is thought that stronger binding at this point is the consequence of interactions between bacterial adhesins and receptors in the salivary ______.

Many proteins in the acquired pellicle can act as receptors for streptococci, including α-amylase, acid proline-rich proteins, statherin, and salivary agglutinin glycoprotein ______.

The specific adhesins of primary colonizing bacteria have been the subject of many investigations, because these represent potential targets for interference with the formation of dental ______.

One of the best-characterized interactions is the binding between the antigen I/II family adhesins of oral streptococci and ______.

Gp340 is present in fluid-phase saliva, and it is a component of the salivary ______.

Coaggregation is a direct interaction; it is distinct from ______, which occurs when cells are stuck together by molecules in solution.

The initial stages of coaggregation or coadhesion are essentially the same as the first steps involved in bacterial binding to surfaces: bacterial cells come into contact through passive or active transport and bind weakly through nonspecific hydrophobic, electrostatic, and van der Waals ______.

Primary colonizers Streptococcus gordonii, Streptococcus intermedius, Streptococcus mitis, Streptococcus oralis, Streptococcus sanguinis, Actinomyces gerencseriae, Actinomyces israelii, Actinomyces naeslundii, Actinomyces oris, and Aggregatibacter actinomycetemcomitans serotype a are examples of ______ colonizers.

In the context of plaque formation, coaggregation between different gram negative species is likely to ______.

The complementary sets of adhesin receptor symbols represent the various kinds of coaggregations as well as the interactions with molecules in the ______.

Streptococcus salivarius and Streptococcus mitis are the first and most dominant oral microbes to colonize the oral cavity of newborn infants, followed by Veillonella spp., Neisseria spp., Actinomyces spp., and Staphylococcus spp. After tooth eruption, a more complex oral microbiota is established. The species that colonize the teeth after eruption include Streptococcus sanguinis, Lactobacillus spp., and ______

Commonly reported to be present after the first year of life are oral streptococci, including S. oralis, Streptococcus anginosus, mutans streptococci (Streptococcus mutans and Streptococcus sobrinus), and Streptococcus gordonii. In addition, anaerobes, including Fusobacterium spp. and ______, can also be detected in young children.

In later childhood, the bacterial diversity and numbers in the oral cavity increase as more teeth erupt and provide more areas for the adherence and retention of bacteria. Because of the paucity of longitudinal studies, relatively little is known about the initial colonization of key microbes found in the oral cavity of children and adults. It is estimated that more than 500 different species are capable of colonizing the adult mouth and that any individual typically harbors around 50 to 150 different species. When one thinks about bacteria, one almost immediately associates them with different pathologies. However, most oral bacteria are harmless commensals under normal circumstances. This means that this microbiota lives in harmony with its host but that, under specific conditions (i.e., increased mass and/or pathogenicity, suppression of commensal or beneficial bacteria, and/or reduced host response), disease can occur. The importance of the commensal microbiota is clearly illustrated by the development of yeast infections when the normal oral microbiota is reduced, such as after a longer period of systemic antibiotic usage. In addition, it has been shown that aggressive periodontitis is associated with a loss of colonization of S. sanguinis.

In periodontal pockets, studies have shown high numbers of bacteria attached to pocket epithelial cells in vivo. Areas of gingival inflammation are characterized by an increased number of adhering bacteria. These adhering bacteria can also infiltrate the pocket wall in relatively large numbers and reach the underlying stroma. In general, there is a positive correlation between the adhesion rate of pathogenic bacteria to different epithelia and the susceptibility of the affected patient to certain infections. In the periodontal pocket, different strategies contribute to bacterial survival, such as adhesion to the pocket epithelium and, when dentine is encountered, the colonization of the dentine tubules.The crevicular fluid with its constant outflow does not favor the maintenance of unattached bacteria in the periodontal pocket. It has been suggested that teeth are the primary habitat for periodontopathogens, because soon after a full-mouth tooth extraction in patients with severe periodontitis, key pathogens such as A. actinomycetemcomitans and P. gingivalis disappeared from the oral cavity as determined by bacterial culturing techniques.

In health, there is a core set of microorganisms that are almost universally present in oral ecosystems. This core microbiome includes members of the phyla Firmicutes (Streptococcus spp., Veillonella spp., and Granulicatella spp.), Proteobacteria (Neisseria spp., Campylobacter spp., and Haemophilus spp.), Actinobacteria (Corynebacterium spp., Rothia spp., and Actinomyces spp.).