The document discusses the oral microbiota. It begins by explaining that the mouth is a diverse microbial habitat containing over 700 bacterial species. Key factors that support microbial growth in the oral cavity include teeth, saliva, specialized mucosal surfaces, and gingival crevicular fluid. The microflora is acquired early in life and remains stable, though it can be impacted by factors like pH, nutrients, temperature and host defenses. The major groups of bacteria found endogenously in the oral cavity are also outlined.
Oral microflora /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Oral microflora /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Oral micro flora/dental crown &bridge course by Indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Oral micro flora/certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The oral cavity hosts a complex ecology of microbial populations that compete for available nutrients. While most oral bacteria grow best at a narrow pH range, some aciduric bacteria can grow at low pH levels and are favored in acidic environments. Sugar is the main energy source, but some bacteria can use other substrates like carboxylic acids. Key bacterial adaptations include maintaining metabolism at low pH, rapidly transporting sugars, and producing extracellular and intracellular polysaccharides. Major cariogenic bacteria associated with dental caries include Streptococcus mutans, Lactobacillus, Actinomyces, and Veillonella. Dental caries results from the net acid production of the overall plaque microflora through multiple bacterial interactions, competitions,
Oral microbiology:normal oram microflora and Dental plaqueKarishma Sirimulla
This document discusses oral microbiology and dental plaque. It begins by introducing the types of microorganisms found in the oral cavity, including bacteria, fungi, and protozoa. It then discusses the normal oral microflora, including indigenous, supplemental, and transient flora. Key topics covered include the various types of oral bacteria; factors that affect bacterial growth such as temperature, pH, nutrients, and host defenses; bacterial metabolism of carbohydrates, proteins, oxygen, and nitrogen; and the definition and formation of dental plaque.
This document discusses microorganisms found in the oral cavity and their role in oral infections. It begins by describing the normal oral flora, including the most common bacteria present in healthy individuals. It then discusses factors that determine bacterial growth in the mouth and how the oral flora develops from infancy to adulthood. The document also describes how microorganisms can be retained in the oral cavity and form biofilms. It discusses pathways of endodontic infections and microorganisms commonly found in infected root canals and periapical tissues.
Oral microbiology/ rotary endodontic courses by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Oral microflora /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Oral microflora /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
Oral micro flora/dental crown &bridge course by Indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Oral micro flora/certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The oral cavity hosts a complex ecology of microbial populations that compete for available nutrients. While most oral bacteria grow best at a narrow pH range, some aciduric bacteria can grow at low pH levels and are favored in acidic environments. Sugar is the main energy source, but some bacteria can use other substrates like carboxylic acids. Key bacterial adaptations include maintaining metabolism at low pH, rapidly transporting sugars, and producing extracellular and intracellular polysaccharides. Major cariogenic bacteria associated with dental caries include Streptococcus mutans, Lactobacillus, Actinomyces, and Veillonella. Dental caries results from the net acid production of the overall plaque microflora through multiple bacterial interactions, competitions,
Oral microbiology:normal oram microflora and Dental plaqueKarishma Sirimulla
This document discusses oral microbiology and dental plaque. It begins by introducing the types of microorganisms found in the oral cavity, including bacteria, fungi, and protozoa. It then discusses the normal oral microflora, including indigenous, supplemental, and transient flora. Key topics covered include the various types of oral bacteria; factors that affect bacterial growth such as temperature, pH, nutrients, and host defenses; bacterial metabolism of carbohydrates, proteins, oxygen, and nitrogen; and the definition and formation of dental plaque.
This document discusses microorganisms found in the oral cavity and their role in oral infections. It begins by describing the normal oral flora, including the most common bacteria present in healthy individuals. It then discusses factors that determine bacterial growth in the mouth and how the oral flora develops from infancy to adulthood. The document also describes how microorganisms can be retained in the oral cavity and form biofilms. It discusses pathways of endodontic infections and microorganisms commonly found in infected root canals and periapical tissues.
Oral microbiology/ rotary endodontic courses by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
This document provides an overview of the microbiology of the oral cavity. It discusses the resident oral microflora including the major groups of microorganisms found, such as streptococci. Specifically, it focuses on the Streptococcus mutans group, detailing their role in dental caries, characteristics, ecology, physiology and screening tests. It also briefly discusses other streptococcal groups commonly found in the oral cavity like S. salivarius and S. milleri groups.
The document discusses the normal oral microflora and dental plaque. Regarding normal oral microflora, it describes the different bacterial species present in different areas of the oral cavity and factors that determine their distribution. Regarding dental plaque, it defines plaque, describes its classification and the successive stages of development from pellicle formation to maturation of the microbial community. Key bacterial species involved in early and late colonization are mentioned.
The document discusses the oral microbiome and factors that influence it. It begins by defining key terms like microbiota, habitat, and ecology. It then describes the four major ecosystems in the oral cavity and how they each support different microbial communities. Factors that affect microbial growth like temperature, pH, nutrients, and host defenses are also examined. The document outlines the succession of bacterial colonization from pioneer species in infants to the climax community of diverse bacteria in adults. It provides an overview of the normal oral microbiome and its development.
The document discusses dental plaque formation and ecology. It begins by defining dental plaque and describing its bacterial composition. It then discusses the stages of plaque formation from pellicle formation to mature plaque development. The document also covers plaque retention sites, plaque disclosure methods, and classifications. It describes the hypotheses concerning plaque pathogenicity, including the non-specific, specific, and ecological plaque hypotheses. The strategies for caries prevention and control based on the ecological plaque hypothesis are preventing shifts in the microbial ecology through dietary and oral hygiene interventions. In healthy circumstances, the resident oral flora are generally not disease-causing, but environmental changes can trigger shifts to more cariogenic microbial compositions.
etiology and pathogenies of dental caries.pptxraniaasaad3
This document discusses the etiology and pathogenesis of dental caries. It begins with introducing the topics of etiology and pathology. It then discusses dental caries in more detail, describing it as a chronic infectious disease caused by cariogenic bacteria metabolizing sugars and producing acid. This acid demineralizes tooth structure over time. The document goes on to discuss dental plaque biofilm, the theories of dental caries, factors affecting the role of sugars in caries development like the Stephan curve, and host factors influencing caries like age, diet, saliva composition and flow rate.
Dental plaque forms through sequential colonization of microorganisms on tooth surfaces. It is made up of bacteria, epithelial cells, and extracellular matrix. Plaque formation involves acquired pellicle formation, reversible bacterial attachment, irreversible attachment through adhesins, microbial succession through coaggregation, and maturation of the biofilm and matrix. The microbial composition of plaque varies by oral site and influences diseases like periodontitis and dental caries. Periodontitis results from an imbalance in homeostasis allowing pathogenic bacteria to overgrow. Dental caries occurs when frequent sugar consumption in plaque favors acid-tolerant bacteria like mutans streptococci, changing the microbiota and predisposing to demineralization.
Oral health is inextricably linked to general health, and vice versa.
The mouth is the gateway of the body to the external world and represents one of the most biologically complex sites in the body.
The document discusses the defense mechanisms of the gingiva that help it withstand various adverse environmental conditions. There are nonspecific and specific defense mechanisms. Nonspecific mechanisms include the anatomical structure of the gingiva, the mucous barrier formed by saliva and gingival crevicular fluid, and tissue resistance. Specific mechanisms include the host-microbial symbiosis provided by beneficial commensal bacteria and the local inflammatory response. Saliva plays an important role through its antibacterial factors such as antibodies, enzymes, and buffers that help maintain pH and protect against pathogens. The gingival crevicular fluid also acts as a permeable barrier, with its production increased during inflammation. These defense mechanisms work together to keep the
This document discusses dental plaque/biofilm, including its definition, classification, composition, properties, and factors that affect its composition. It begins by defining dental plaque as a host-associated biofilm that adheres tenaciously to intraoral hard surfaces. Plaque is classified as supragingival or subgingival based on its location relative to the gingival margin. The composition of plaque includes water, organic constituents like bacteria and carbohydrates, and inorganic constituents like calcium and phosphorus. Properties include its structure, exopolysaccharides that form its backbone, physiological heterogeneity, quorum sensing, and increased antibiotic resistance of bacteria within it. Factors like periodontal disease status, the local environment, transmission from other individuals,
The document discusses the oral microbiome. It begins by introducing key terms and describing the oral ecosystem and habitats that support diverse microbial communities. It then details the development of the normal oral flora from birth through adulthood and how factors like teeth eruption influence community composition over time. Major groups of bacteria, fungi and other microbes that comprise the oral microbiome are also outlined. Physicochemical factors like temperature, oxygen levels, and pH that shape microbial colonization are explained.
This document discusses the microbial flora of the oral cavity. It describes the various microbial habitats in the mouth and the acquisition of normal flora beginning at birth. The major types of flora are discussed as well as factors that modulate microbial growth. The document also examines the oral microbiome's role in oral diseases and conditions like dental caries, periodontal disease, and infections. Additionally, it summarizes how orthodontic appliances can impact the oral microbiome by facilitating plaque accumulation and altering the microbial environment. Maintaining proper oral hygiene is emphasized when wearing orthodontic appliances.
The document discusses the oral microflora, including the different oral habitats that microorganisms inhabit, such as the teeth, oral mucosa, tongue, and saliva. It describes the various microorganisms commonly found in the oral cavity, including streptococci, actinomyces, and candida albicans. It also defines several terms related to oral microflora and their ecology.
Microbiology of dental caries/ orthodontic course by indian dental academyIndian dental academy
This document discusses dental caries and summarizes key points about its multifactorial causes and pathogenesis. It describes dental caries as caused by an interaction between host factors, microflora, diet/substrate, and time. Host factors include tooth morphology, composition, saliva properties, and immunization. Saliva helps protect teeth through its buffering ability, antibacterial components like lactoferrin and lysozyme, and role in mineralization. Components like amylase, statherin, and proline-rich proteins both aid and potentially harm dental health. Understanding caries as resulting from these complex interactions can help inform prevention and treatment approaches.
- The oral cavity is colonized by bacteria starting at birth, with Streptococcus salivarius and Streptococcus mitis among the first. Over time, the microbiome shifts and becomes more diverse.
- The oral cavity can be divided into six major ecosystems from a microbe's perspective, including the teeth and implants which provide a unique hard, nonshedding surface for bacterial biofilms to form.
- Dental plaque formation occurs in stages, starting with the salivary pellicle coating teeth, followed by initial bacterial adhesion and colonization as the biofilm matures over days and the microbiome changes in composition.
The document discusses the oral microbiota and its role in various oral diseases. It begins with an introduction to oral microbiology and a brief history. It then describes the normal microbial flora of the oral cavity including bacteria, fungi and protozoa. Several key bacteria associated with dental diseases like dental caries and periodontal disease are mentioned. The document also discusses the development of oral flora from infancy to adulthood. Various diseases caused by oral microbes like dental plaque, caries, periodontitis and endodontic infections are summarized. Sample collection and diagnostic methods for oral pathogens are also outlined.
This document discusses the immunology of dental caries. It begins by describing how the oral flora develops from birth and the role of bacteria like Streptococcus mutans in dental caries. Dental caries is considered a biofilm-induced disease. Key points include that S. mutans is a significant pathogen in enamel caries and lactobacillus is predominant in dentinal caries. The document also discusses potential caries vaccines and notes their development has focused on subunit vaccines to avoid potential heart-reactive antibodies induced by whole cell vaccines. In conclusion, while current prevention methods are not sufficient, a successful caries vaccine could make a significant contribution to disease control.
This document provides an overview of the diversity of microorganisms that make up the resident oral microbiota. It discusses the classification and identification of numerous bacteria, fungi, viruses, and other microbes found in the oral cavity. Key points covered include the variety of gram-positive and gram-negative bacteria isolated from the oral cavity, both aerobic and anaerobic species, and the diseases some opportunistic pathogens can cause. Molecular methods for identifying microbes are also summarized as being more accurate and able to detect non-culturable species compared to conventional techniques.
Periodontal diseases are caused by a complex interplay between multiple local and systemic factors that influence the host response to the bacterial biofilm (plaque) that forms on the teeth. The plaque is composed of hundreds of bacterial species organized in a matrix on the tooth surface. As plaque matures, the proportion of gram-negative anaerobic bacteria increases, enhancing its pathogenicity. Subgingival plaque is more pathogenic than supragingival plaque due to its protected location below the gumline. The composition and virulence of the plaque, as well as the host immune response, determine the severity and progression of periodontal disease.
MODIFIED EDEN BAYSAL DENTAL TRAUMA INDEX (MEBDTI)
Traumatic dental injuries (TDI) are common in both the primary and permanent dentitions.
Using a standardized index to record the entire dental and ST injuries would result in the possibility of more robust data from various centers.
This document provides an overview of the microbiology of the oral cavity. It discusses the resident oral microflora including the major groups of microorganisms found, such as streptococci. Specifically, it focuses on the Streptococcus mutans group, detailing their role in dental caries, characteristics, ecology, physiology and screening tests. It also briefly discusses other streptococcal groups commonly found in the oral cavity like S. salivarius and S. milleri groups.
The document discusses the normal oral microflora and dental plaque. Regarding normal oral microflora, it describes the different bacterial species present in different areas of the oral cavity and factors that determine their distribution. Regarding dental plaque, it defines plaque, describes its classification and the successive stages of development from pellicle formation to maturation of the microbial community. Key bacterial species involved in early and late colonization are mentioned.
The document discusses the oral microbiome and factors that influence it. It begins by defining key terms like microbiota, habitat, and ecology. It then describes the four major ecosystems in the oral cavity and how they each support different microbial communities. Factors that affect microbial growth like temperature, pH, nutrients, and host defenses are also examined. The document outlines the succession of bacterial colonization from pioneer species in infants to the climax community of diverse bacteria in adults. It provides an overview of the normal oral microbiome and its development.
The document discusses dental plaque formation and ecology. It begins by defining dental plaque and describing its bacterial composition. It then discusses the stages of plaque formation from pellicle formation to mature plaque development. The document also covers plaque retention sites, plaque disclosure methods, and classifications. It describes the hypotheses concerning plaque pathogenicity, including the non-specific, specific, and ecological plaque hypotheses. The strategies for caries prevention and control based on the ecological plaque hypothesis are preventing shifts in the microbial ecology through dietary and oral hygiene interventions. In healthy circumstances, the resident oral flora are generally not disease-causing, but environmental changes can trigger shifts to more cariogenic microbial compositions.
etiology and pathogenies of dental caries.pptxraniaasaad3
This document discusses the etiology and pathogenesis of dental caries. It begins with introducing the topics of etiology and pathology. It then discusses dental caries in more detail, describing it as a chronic infectious disease caused by cariogenic bacteria metabolizing sugars and producing acid. This acid demineralizes tooth structure over time. The document goes on to discuss dental plaque biofilm, the theories of dental caries, factors affecting the role of sugars in caries development like the Stephan curve, and host factors influencing caries like age, diet, saliva composition and flow rate.
Dental plaque forms through sequential colonization of microorganisms on tooth surfaces. It is made up of bacteria, epithelial cells, and extracellular matrix. Plaque formation involves acquired pellicle formation, reversible bacterial attachment, irreversible attachment through adhesins, microbial succession through coaggregation, and maturation of the biofilm and matrix. The microbial composition of plaque varies by oral site and influences diseases like periodontitis and dental caries. Periodontitis results from an imbalance in homeostasis allowing pathogenic bacteria to overgrow. Dental caries occurs when frequent sugar consumption in plaque favors acid-tolerant bacteria like mutans streptococci, changing the microbiota and predisposing to demineralization.
Oral health is inextricably linked to general health, and vice versa.
The mouth is the gateway of the body to the external world and represents one of the most biologically complex sites in the body.
The document discusses the defense mechanisms of the gingiva that help it withstand various adverse environmental conditions. There are nonspecific and specific defense mechanisms. Nonspecific mechanisms include the anatomical structure of the gingiva, the mucous barrier formed by saliva and gingival crevicular fluid, and tissue resistance. Specific mechanisms include the host-microbial symbiosis provided by beneficial commensal bacteria and the local inflammatory response. Saliva plays an important role through its antibacterial factors such as antibodies, enzymes, and buffers that help maintain pH and protect against pathogens. The gingival crevicular fluid also acts as a permeable barrier, with its production increased during inflammation. These defense mechanisms work together to keep the
This document discusses dental plaque/biofilm, including its definition, classification, composition, properties, and factors that affect its composition. It begins by defining dental plaque as a host-associated biofilm that adheres tenaciously to intraoral hard surfaces. Plaque is classified as supragingival or subgingival based on its location relative to the gingival margin. The composition of plaque includes water, organic constituents like bacteria and carbohydrates, and inorganic constituents like calcium and phosphorus. Properties include its structure, exopolysaccharides that form its backbone, physiological heterogeneity, quorum sensing, and increased antibiotic resistance of bacteria within it. Factors like periodontal disease status, the local environment, transmission from other individuals,
The document discusses the oral microbiome. It begins by introducing key terms and describing the oral ecosystem and habitats that support diverse microbial communities. It then details the development of the normal oral flora from birth through adulthood and how factors like teeth eruption influence community composition over time. Major groups of bacteria, fungi and other microbes that comprise the oral microbiome are also outlined. Physicochemical factors like temperature, oxygen levels, and pH that shape microbial colonization are explained.
This document discusses the microbial flora of the oral cavity. It describes the various microbial habitats in the mouth and the acquisition of normal flora beginning at birth. The major types of flora are discussed as well as factors that modulate microbial growth. The document also examines the oral microbiome's role in oral diseases and conditions like dental caries, periodontal disease, and infections. Additionally, it summarizes how orthodontic appliances can impact the oral microbiome by facilitating plaque accumulation and altering the microbial environment. Maintaining proper oral hygiene is emphasized when wearing orthodontic appliances.
The document discusses the oral microflora, including the different oral habitats that microorganisms inhabit, such as the teeth, oral mucosa, tongue, and saliva. It describes the various microorganisms commonly found in the oral cavity, including streptococci, actinomyces, and candida albicans. It also defines several terms related to oral microflora and their ecology.
Microbiology of dental caries/ orthodontic course by indian dental academyIndian dental academy
This document discusses dental caries and summarizes key points about its multifactorial causes and pathogenesis. It describes dental caries as caused by an interaction between host factors, microflora, diet/substrate, and time. Host factors include tooth morphology, composition, saliva properties, and immunization. Saliva helps protect teeth through its buffering ability, antibacterial components like lactoferrin and lysozyme, and role in mineralization. Components like amylase, statherin, and proline-rich proteins both aid and potentially harm dental health. Understanding caries as resulting from these complex interactions can help inform prevention and treatment approaches.
- The oral cavity is colonized by bacteria starting at birth, with Streptococcus salivarius and Streptococcus mitis among the first. Over time, the microbiome shifts and becomes more diverse.
- The oral cavity can be divided into six major ecosystems from a microbe's perspective, including the teeth and implants which provide a unique hard, nonshedding surface for bacterial biofilms to form.
- Dental plaque formation occurs in stages, starting with the salivary pellicle coating teeth, followed by initial bacterial adhesion and colonization as the biofilm matures over days and the microbiome changes in composition.
The document discusses the oral microbiota and its role in various oral diseases. It begins with an introduction to oral microbiology and a brief history. It then describes the normal microbial flora of the oral cavity including bacteria, fungi and protozoa. Several key bacteria associated with dental diseases like dental caries and periodontal disease are mentioned. The document also discusses the development of oral flora from infancy to adulthood. Various diseases caused by oral microbes like dental plaque, caries, periodontitis and endodontic infections are summarized. Sample collection and diagnostic methods for oral pathogens are also outlined.
This document discusses the immunology of dental caries. It begins by describing how the oral flora develops from birth and the role of bacteria like Streptococcus mutans in dental caries. Dental caries is considered a biofilm-induced disease. Key points include that S. mutans is a significant pathogen in enamel caries and lactobacillus is predominant in dentinal caries. The document also discusses potential caries vaccines and notes their development has focused on subunit vaccines to avoid potential heart-reactive antibodies induced by whole cell vaccines. In conclusion, while current prevention methods are not sufficient, a successful caries vaccine could make a significant contribution to disease control.
This document provides an overview of the diversity of microorganisms that make up the resident oral microbiota. It discusses the classification and identification of numerous bacteria, fungi, viruses, and other microbes found in the oral cavity. Key points covered include the variety of gram-positive and gram-negative bacteria isolated from the oral cavity, both aerobic and anaerobic species, and the diseases some opportunistic pathogens can cause. Molecular methods for identifying microbes are also summarized as being more accurate and able to detect non-culturable species compared to conventional techniques.
Periodontal diseases are caused by a complex interplay between multiple local and systemic factors that influence the host response to the bacterial biofilm (plaque) that forms on the teeth. The plaque is composed of hundreds of bacterial species organized in a matrix on the tooth surface. As plaque matures, the proportion of gram-negative anaerobic bacteria increases, enhancing its pathogenicity. Subgingival plaque is more pathogenic than supragingival plaque due to its protected location below the gumline. The composition and virulence of the plaque, as well as the host immune response, determine the severity and progression of periodontal disease.
Similar to SEMINAR III ORAL MICROFLORA PART.pptx (20)
MODIFIED EDEN BAYSAL DENTAL TRAUMA INDEX (MEBDTI)
Traumatic dental injuries (TDI) are common in both the primary and permanent dentitions.
Using a standardized index to record the entire dental and ST injuries would result in the possibility of more robust data from various centers.
Pulpectomy is the procedure of extirpating the diseased pulp associated with microorganism and debris from the canal and obturating with an antibacterial resorbable filling material and it is indicated when the inflammation of the pulpal tissue involves the radicular pulp or when nonvital tooth is diagnosed.
Obturating the canal creates a fluid tight seal along the length of the root from the coronal opening to the apical system and eliminating all portals of entry between the periodontium and the root canal system.
Stainless steel crowns are prefabricated crown forms that are adapted to individual teeth and cemented with a biocompatible luting agent. “The SSC is extremely durable, relatively inexpensive, subject to minimal technique sensitivity during placement, and offers the advantage of full coronal coverage.”
SEMINAR V & VI TRIGEMINAL NERVE AND ITS CLINICAL IMPORTANCE FINAL.pptxPrem Chauhan
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Fothergill’s disease/tic douloureux
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Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
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Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
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www.agostodourado.com
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...Donc Test
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by Stamler, Verified Chapters 1 - 33, Complete Newest Version Community Health Nursing A Canadian Perspective, 5th Edition by Stamler, Verified Chapters 1 - 33, Complete Newest Version Community Health Nursing A Canadian Perspective, 5th Edition by Stamler Community Health Nursing A Canadian Perspective, 5th Edition TEST BANK by Stamler Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Pdf Chapters Download Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Pdf Download Stuvia Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Study Guide Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Ebook Download Stuvia Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Questions and Answers Quizlet Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Studocu Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Quizlet Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Pdf Chapters Download Community Health Nursing A Canadian Perspective, 5th Edition Pdf Download Course Hero Community Health Nursing A Canadian Perspective, 5th Edition Answers Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Ebook Download Course hero Community Health Nursing A Canadian Perspective, 5th Edition Questions and Answers Community Health Nursing A Canadian Perspective, 5th Edition Studocu Community Health Nursing A Canadian Perspective, 5th Edition Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Pdf Chapters Download Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Pdf Download Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Study Guide Questions and Answers Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Ebook Download Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Questions Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Studocu Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Stuvia
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
2. CONTENTS
◎ INTRODUCTION
◎ THE MOUTH AS A MICROBIAL HABITAT
◎ FACTORS AFFECTING THE GROWTH OF MICROORGANISMS IN THE ORAL
CAVITY
◎ HUMAN ORAL FLORA
◎ ACQUISITION OF THE RESIDENT ORAL MICROFLORA
◎ AGEING AND THE ORAL MICROFLORA
◎ DISTRIBUTION OF THE RESIDENT ORAL MICROFLORA
◎ METABOLISM OF ORAL BACTERIA
◎ BENEFITS OF THE ORAL MICROBIOTA
3. INTRODUCTION
◎ Human body is made up of over 1014 cells of which only around 10% are mammalian. The
remainder are the microorganisms that comprise the resident microflora of the host.
◎ This resident microflora does not have merely a passive relationship with its host, but
contributes directly and indirectly to the normal development of the physiology, nutrition
and defence systems of the organism.
◎ In general, these natural microfloras live in harmony with humans and animals and, indeed,
all parties benefit from the association. Loss or perturbation of this resident microflora can
lead to colonization by exogenous (and often pathogenic) microorganisms, thereby
predisposing sites to disease.
4. ◎ The oral cavity is a border area between the environment and the human organism, a
gateway for food, an outpost of the immune system and above all a multilayered habitat
inhabited by countless microorganisms.
◎ The mouth is continually exposed to organisms from the external environment ,beginning
with the passage through the birth canal.
◎ In time a ecological balance is reached that serves to establish a resident microbial flora
that remains fairly stable throughout life.
◎ Microorganisms in mouth were first described by Anton von Leeuwenhoek in 1683.
5. THE MOUTH AS A MICROBIAL HABITAT
◎ Not all of the micro-organisms that enter the mouth are able to colonize. The properties of
the mouth make it ecologically distinct from all other surfaces of the body, and dictate the
types of microbe able to persist. Habitats that provide obviously different ecological
conditions include mucosal surfaces (such as the lips, cheek, palate and tongue) and teeth.
◎ Ecological conditions within the mouth will also vary during the change from the primary
to the permanent dentition and following the extraction of teeth, the insertion of prostheses
such as dentures, and any dental treatment, including scaling, polishing and fillings.
◎ Transient fluctuations in the stability of the oral ecosystem may be induced by the
frequency and type of food ingested, variations in saliva flow and periods of antibiotic
therapy.
6. ◎ Four features that help to make the oral cavity distinct from other
areas of the body are:
1. Teeth
2. Specialized mucosal surfaces
3. Saliva
4. Gingival crevicular fluid
7. TEETH
◎ The mouth is the only normally-
accessible site in the body that has hard
non-shedding surfaces for microbial
colonization.
◎ Teeth (and dentures) allow the
accumulation of large masses of
microorganisms (predominantly
bacteria) and their extracellular
products, termed dental plaque.
◎ Teeth do not provide a uniform habitat
but possess several distinct surfaces
each of which is optimal for
colonization and growth by different
populations of microorganism.
8. SPECIALIZED MUCOSAL SURFACES
◎ The oral cavity have specialized surfaces
which contribute to the diversity of the
microflora at certain sites.
◎ The papillary structure of the dorsum of
the tongue provides refuge for many
micro-organisms which would otherwise
be removed by mastication and the flow of
saliva
◎ The mouth also contains keratinized (e.g.
the palate) as well as non-keratinized,
stratified squamous epithelium which may
affect the intra-oral distribution of some
micro-organisms.
9. SALIVA
◎ The mouth is kept moist and lubricated by saliva which flows over all the internal surfaces
of the oral cavity. Saliva enters the oral cavity via ducts from the major paired parotid,
submandibular and sublingual glands as well as from the minor glands of the oral mucosa
(labial, lingual, buccal and palatal glands) where it is produced.
◎ Saliva contains several ions including sodium, potassium, calcium, chloride, bicarbonate
and phosphate .
◎ Some of these ions contribute to the buffering property of saliva which can reduce the
cariogenic effect of acids produced from the bacterial metabolism of dietary carbohydrates.
Bicarbonate is the major buffering system in saliva but phosphates, peptides and proteins
are also involved.
◎ The mean pH of saliva is between pH 6.75 and 7.25, although the pH and buffering
capacity will vary with the flow rate.
10. ◎ Within a mouth, the flow rate and the concentration of components such as proteins and
calcium and phosphate ions have circadian rhythms, with the slowest flow of saliva
occurring during sleep. Thus, it is important to avoid consuming sugary foods or drinks
before sleeping because the protective functions of saliva are reduced.
◎ The major organic constituents of saliva are proteins and glycoproteins, such as mucin, and
they influence the oral microflora by:
1. Adsorbing to the tooth surface to form a conditioning film (the acquired pellicle), which
determines which microorganisms are able to attach.
2. Acting as primary sources of nutrients (carbohydrates and proteins) for the resident
microflora.
3. Aggregating exogenous microorganisms, thereby facilitating their clearance from the
mouth by swallowing.
4. Inhibiting the growth of some exogenous microorganisms.
11.
12. GINGIVAL CREVICULAR FLUID (GCF)
◎ Serum components can reach the mouth by the flow of a
serum-like fluid through the junctional epithelium of the
gingivae. The flow of GCF is relatively slow at healthy
sites, but increases during inflammation.
◎ GCF can influence the site by acting as a novel source of
nutrients, while its flow will remove nonadherent
microbial cells.
◎ GCF also contains components of the host defenses
which play an important role in regulating the microflora
of the gingival crevice in health and disease. The
neutrophils in GCF are viable and can phagocytose
bacteria within the crevice.
13. FACTORS AFFECTING THE GROWTH OF
MICROORGANISMS IN THE ORAL CAVITY
◎ Temperature
◎ Redox potential
◎ pH
◎ Nutrients
◎ Adherence and agglutination
◎ Anti-microbial agents.
◎ Host defence
◎ Host genetics
14. TEMPERATURE
◎ The human mouth is kept at a relatively constant temperature (35–36°C) which provides
stable conditions suitable for the growth of a wide range of microorganisms.
◎ Periodontal pockets with active disease (inflammation) have a higher temperature (up to
39°C) compared with healthy sites. Even such relatively small rises in temperature can
significantly alter bacterial gene expression, and possibly the competitiveness of individual
species.
◎ A rise in temperature down-regulated expression of some of the major proteases as well as
the gene coding for the major subunit protein of fimbriae in the periodontal pathogen,
Porphyromonas gingivalis
◎ Up-regulated synthesis of superoxide dismutase, which is involved in the neutralization of
toxic oxygen metabolites.
15. REDOX POTENTIAL/ANAEROBIOSIS
◎ Tissues or microbes that need a positive Eh for viability are termed "aerobes," and those
that need a negative Eh are "anaerobes”.
◎ Anaerobic species require reduced conditions for their normal metabolism; therefore, it is
the degree of oxidation-reduction (redox potential, Eh) at a site that governs their survival.
◎ Some anaerobes can survive at aerobic habitats by existing in close partnership with
oxygen consuming species. Obligate anaerobes also possess specific molecular defence
mechanisms that suitable for the survival and growth of a changing pattern of organisms,
and partenable them to cope with low redox potential (highly reduced).
16. ◎ The development of plaque in this way is associated with a specific succession of
microorganisms . Early colonizers will utilize O2 and produce CO2; later colonizers may
produce H2 and other reducing agents such as sulphur containing compounds and volatile
fermentation products.
◎ Thus, as the redox potential is gradually lowered, sites become icularly anaerobes.
◎ Periodontal pockets are more reduced ( - 48 m V) than healthy gingival crevices in the
same individuals (+ 73 m V). Gradients of O2 concentration and Eh will exist in the oral
cavity, particularly in a thick biofilm such as plaque.
◎ The redox potential will also affect bacterial metabolism. e.g. the activity intracellular
glycolytic enzymes and the pattern of fermentation products of Streptococcus mutants
varies under strictly anaerobic conditions. Thus, modifications to the habitat that disturb
such gradients may influence the composition and metabolism of the microbial community.
17. pH
◎ Many micro-organisms require a pH around neutrality for growth, and are sensitive to
extremes of acid or alkali. The pH of most surfaces of the mouth is regulated by saliva so
that, in general, optimum pH values for microbial growth are provided at sites bathed by
this fluid.
◎ Bacterial population shifts within the plaque microflora can occur following fluctuations in
environmental pH after sugar consumption, the pH in plaque can fall rapidly to below pH
5.0 by the production of acids (predominantly lactic acid) by bacterial metabolism slowly
to base-line values then pH recovers.
◎ Depending on the frequency of sugar intake, the bacteria in plaque will be exposed to
varying challenges of low pH. Many of the predominant plaque bacteria from healthy sites
can tolerate only brief conditions of low pH, and are inhibited or killed by more frequent or
prolonged exposures to acidic conditions.
18. ◎ This can result in the enhanced growth of, or colonization by, acid-tolerant species,
especially mutans streptococci and Lactobacillus species, which are normally absent or
only minor components in dental plaque at healthy sites. Such a change in the bacterial
composition of plaque predisposes a surface to dental caries.
◎ In contrast, the pH of the gingival crevice becomes alkaline during the host inflammatory
response in periodontal disease, e.g. following deamination of amino acids and ammonia
production. The mean pH may rise to between pH 7.2 and 7.4 during disease, with a few
patients having pockets with a mean pH of around 7.8.
◎ This degree of change may perturb the balance of the resident microflora of gingival
crevice by favouring the growth and metabolism of periodontal pathogens, such as
Porphyromonas gingivalis, that have pH optima for growth above pH 7.5.
19. NUTRIENTS
◎ The association of an organism with a particular habitat is direct evidence that all of the
necessary growth-requiring nutrients are present. The mouth can support a microbial
community of great diversity and satisfy the requirements of many nutritionally demanding
bacterial population.
20. ENDOGENOUS NUTRIENTS
◎ The persistence and diversity of the resident oral microflora is due primarily to the
metabolism of the endogenous nutrients provided by the host, rather than by exogenous
factors in the diet. The main source of endogenous nutrients saliva, which contains amino
acids, peptides, proteins and glycoproteins, vitamins and gases.
◎ In addition, the gingival crevice is supplied with GCF which, in addition to delivering
components of the host defences, contains potential sources of novel nutrients, such as
albumin and other host proteins and glycoproteins, including haeme containing molecules.
◎ Plaque bacteria proteases, and produce glycosidase interact synergistically and to
breakdown these endogenous nutrients as no single species has the full enzyme
complement to totally metabolize these nutrients.
21. E X O G E N O U S N U T R I E N T S
◎ Superimposed upon these endogenous nutrients is the complex array of food stuffs ingested
periodically in the diet. Fermentable carbohydrates are the main class of compounds that
influence markedly the ecology of the mouth. Such carbohydrates can be broken down to
acids.
◎ Sucrose can be converted by bacterial enzymes into two classes of polymer (glucans and
fructans) which can be used to consolidate attachment or act as extra cellular nutrient
storage compounds, respectively.
◎ Dairy products (milk, cheese) have some influence on the ecology of the mouth. The
ingestion of milk or milk products can protect the teeth of animals against caries. This may
be due to the buffering capacity of milk proteins or due to decarboxylation of amino acids
after proteolysis since several bacterial species can metabolize casein.
◎ Xylitol is a sugar substitute that has been added to some confectionery; it cannot be
metabolized by oral bacteria and, in addition, xylitol can be inhibitory to the growth of
Streptococcus mutans.
22. ADHERENCE AND AGGLUTINATION
◎ Chewing and the natural flow of saliva (mean rate = 19 ml/h) will detach microorganisms
not firmly attached to an oral surface.
◎ Salivary components can aggregate certain bacteria which facilitates their removal from the
mouth by swallowing. Bacteria are unable to maintain themselves in saliva by cell division
because they are lost at an even faster rate by swallowing.
◎ The molecules responsible for agglutination are mucins. Mucins are high molecular weight
glycoprotein's. These Mucins not only agglutinate oral bacteria, but can also interact with
exogenous pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa, as well
as viruses (e.g. aeruginosa influenza virus)
◎ Dental plaque formation involves an ordered colonization by a range of bacteria. The early
colonizers interact with, and adhere to, saliva coated enamel, while later colonizers bind to
already attached species (co-aggregation).
23. ANTIMICROBIAL AGENTS AND
INHIBITORS
◎ Anti-plaque agents are distinguished from antimicrobials on the basis of their mode of
action. Anti-plaque agents remove already attached cells, or prevent adhesion of new cells
to the tooth surface. Unlike antimicrobials which are designed to kill (bactericidal) or
inhibit the growth (bacteriostatic) of the bacteria.
◎ Both types of agent can be delivered from toothpastes (dentifrices) and mouthwashes.
Antibiotics given systemically or orally for problems at other sites in the body will enter
the mouth via saliva or GCF and affect the stability of the oral microflora
◎ Within a few hours of taking prophylactic high doses of penicillin's, the salivary microflora
can be suppressed permitting the emergence of antibiotic resistant bacteria.
24. HOST DEFENCES
◎ The health of the mouth is dependent on the integrity of the mucosa (and enamel) which
acts as a physical barrier to prevent penetration by micro-organisms or antigens . The host
has a number of additional defence mechanisms which play an important role in
maintaining the integrity of these oral surfaces.
25.
26.
27.
28. HOST GENETICS
◎ Gender and race can influence disease susceptibility, and possibly also affect the
microflora. In an adult periodontitis group, P. gingivalis and Peptostreptococcus anaerobius
were associated more with black subjects whereas, Fusobacterium nucleatum was found
more commonly in white individuals.
◎ The reasons for this are unknown, but may reflect some variation in the local immune
response. The microflora of twin children living together was more similar than that of
unrelated children of the same age. Further analysis showed that the micro flora of identical
twins was more similar than that of fraternal twins, suggesting some genetic control.
32. ACQUISITION OF THE RESIDENT ORAL
MICROFLORA
◎ The foetus in the womb is normally sterile. Despite the widespread possibility of
contamination, the mouth of the newborn baby is usually sterile. However, from the first
feeding onwards, the mouth is regularly inoculated with microorganisms and the process of
acquisition of the resident oral microflora begins.
◎ Acquisition depends on the successive transmission of micro-organisms to the site of
potential colonization. Initially, in the mouth, this is by passive contamination from the
mother, from food, milk and water, and from the saliva of individuals in close proximity to
the baby. S. salivarius, mutans streptococci and some other species transmitted from mother
to child via saliva.
33.
34. ◎ Mutans streptococci found in children appeared identical to those of their mothers in 71 %
of 34 infant-mother pairs examined. No evidence of father to infant transmission of mutans
streptococci was observed, although transmission between spouses may occur with some
periodontal pathogens, such as P. gingivalis.
◎ The first micro-organisms to colonize are termed pioneer species, and collectively they
make up the pioneer microbial community. These pioneer species continue to grow and
colonize until environmental resistance is encountered. This can be due to several limiting
forces (including physical and chemical factors) which act as barriers to further
development.
35.
36. ◎ In the oral cavity, physical factors include the shedding of epithelial cells (desquamation),
and the shear forces from chewing and saliva flow. Nutrient requirements, redox potential,
pH, and the antibacterial properties of saliva can act as chemical barriers limiting growth.
One genus or species is usually predominant during the development of the pioneer
community.
◎ The pioneer micro-organisms are S. salivarius, S. mitis and S. oralis. With time, the
metabolic activity of the pioneer community modifies the environment providing
conditions suitable for colonization by a succession of other populations, by:
1. Changing the local Eh or pH.
2. Modifying or exposing new receptors for attachment.
3. Generating novel nutrients.
37. ◎ Eventually a stable situation is reached with a high species diversity; this is termed the
climax community. A climax community reflects a highly dynamic situation and must not
be regarded as a static state. The diversity of the pioneer oral community increases during
the first few months of life, and several Gram-negative anaerobic species appear .
◎ When the infants were followed longitudinally during the eruption of the primary dentition,
gram-negative anaerobic bacteria were isolated more commonly, and a greater diversity of
species were recovered from around the gingival margin of the newly erupted teeth (infant
mean age = 32 months).
◎ These findings confirmed that the eruption of teeth has a significant ecological impact on
the oral environment, and its resident microflora. The acquisition of some bacteria may
occur optimally only at certain ages.
◎ Studies of the transmission of mutans streptococci to children have identified a specific
'window of infectivity' between 19 and 31 months (median age = 26 months). This opens
up the possibility of targeting preventive strategies over this critical period to reduce the
likelihood of subsequent colonization in the infant.
38. ALLOGENIC AND AUTOGENIC SUCCESSION
◎ Microbial succession -The establishment of a climax community at any oral site involves
a series of phases of development during which the complexity of the microflora increases
◎ Two distinct types of succession have been identified
1. In Allogenic succession, factors of non-microbial origin are responsible for an altered
pattern of community development. For example, the frequency of detection of mutans
streptococci and S. sanguinis in the mouth increases markedly once hard, non-shedding
surfaces are present. This is usually following tooth eruption, but it can also occur after the
insertion of dentures or removable orthodontic appliances, and acrylic obturators in children
with cleft palate.
39.
40. 2. The increase in number and diversity of obligate anaerobes once teeth are present is an
example of autogenic succession in which community development is influenced by
microbial factors. The metabolism of the aerobic and facultatively anaerobic pioneer
species lowers the redox potential in plaque and creates conditions suitable for colonization
by strict anaerobes. Other examples of autogenic succession are the development of food
chains and food webs, whereby the metabolic end product of one organism becomes a
primary nutrient source for another:
41. AGEING AND THE ORAL MICROFLORA
At Birth
◎ The mouth of full term foetus is usually sterile, transient flora from the birth canal may be
acquired.
◎ Mouth then rapidly acquires organisms from mother and from the environment.
◎ It consists of several streptococcal and staphylococcal species with Lactobacilli, Bacillus,
Neisseria and Yeasts.
◎ Streptococcus salivarius is the most common and forms the pioneer community with
Staphylococcus albus.
42. Infancy & Early Childhood
◎ The infant comes into contact with an ever-increasing range of microorganisms and some
become established as part of commensal flora.
◎ The eruption of deciduous teeth provides a new attachment surface and turns Streptococcus
sanguis and mutans as regular inhabitants of oral cavity.
◎ Anaerobes are few in number due to absence of deep gingival crevice.
◎ Actinomyces , Lactobacilli are found regularly.
43. Adolescence
◎ The greatest number of organisms in mouth occur when permanent teeth erupt.
◎ These teeth have deep fissures, larger inter proximal spaces and deeper gingival crevice,
allowing a great increase in anaerobes.
44. Adulthood
◎ Its chief characteristic is its complexity of oral flora.
◎ There is an increase in Bacteroides and Spirochetes with maturity of dental plaque.
◎ As the teeth are lost the available sites for microbial colonisation decreases and several
species diminish disproportionately in numbers.
◎ Edentulous persons harbour few Spirochetes or Bacteroides but carriage of Yeast increases.
◎ S.sanguis & mutans disappear
45. ◎ Some variations in the oral microflora have been discerned in later life and can be attributed
to both direct and indirect effects of ageing.
46. DISTRIBUTION OF THE RESIDENT ORAL
MICROFLORA
◎ The populations making up
the resident microbial
community of the oral
cavity are not found with
equal frequency throughout
the mouth.
◎ The composition of these
communities varies on
distinct surfaces due to
differences in the biological
and physical properties of
each site.
47. LIPS AND PALATE
◎ The lips form the border between the skin microflora (which consists predominantly of
staphylococci, micrococci and Gram positive rods such as Corynebacterium and
Propionibacterium spp.), and that of the mouth (which contains many Gram negative
species and few of the organisms commonly found on the skin surface).
◎ Facultatively anaerobic streptococci comprise a large part of the microflora on the lips.
◎ Candida albicans can colonize damaged lip mucosal surfaces in the corners of the mouth
(‘angular cheilitis’).
◎ The microflora of the normal palate can show large variations between subjects.
◎ The majority of the bacteria are streptococci and actinomyces; veillonellae, haemophili and
Gram negative anaerobes are also regularly recovered but at lower levels.
◎ Candida are not regularly isolated from the normal palate except when dentures are worn;
in this situation, the mucosa of the palate can become infected with C. albicans (denture
stomatitis)
48.
49. CHEEK
◎ Streptococci are the predominant bacteria from the cheek (buccal mucosa), especially
members of the mitis-group, and H. parainfluenzae is also commonly isolated .
◎ Simonsiella spp. are isolated primarily from the cheek cells of humans and animals.
◎ Molecular techniques have confirmed the presence of a range of streptococcal species on
buccal cells, as well as Granulicatella and Gemella spp.
◎ Fluorescent in situ hybridization (FISH) was combined with confocal microscopy, have
shown that some of the species implicated in periodontal disease (A.
actinomycetemcomitans, P. gingivalis, F. nucleatum, P. intermedia, T. forsythia) can gain
refuge inside buccal epithelial cells in healthy people, where they persist as intracellular
polymicrobial communities
50. TONGUE
◎ The dorsum of the tongue with its highly papillated surface has a large surface area and
supports a higher bacterial density and a more diverse microflora than other oral mucosal
surfaces
◎ Streptococci are the most numerous group of bacteria (approximately 40% of the total
cultivable microflora) with salivarius- and mitis-group organisms predominating.
◎ Anaerobic streptococci have also been isolated while Rothia mucilagenosa is found almost
exclusively on the tongue.
◎ Other major groups of bacteria (and their proportions) include Veillonella spp. (16%),
Gram positive rods (16%) of which Actinomyces naeslundii and A. odontolyticus are
common, and haemophili (15%).
◎ Both pigmenting (Prevotella intermedia, P. melaninogenica) and non-pigmenting
anaerobes can be recovered from the tongue and this site is regarded as a potential reservoir
(along with the tonsils) for some of the organisms implicated in periodontal diseases.
51.
52. SALIVA
◎ Although saliva contains up to 108 microorganisms ml−1 it is not considered to have its
own resident microflora.
◎ The normal rate of swallowing ensures that bacteria cannot be maintained in the mouth by
multiplication in saliva.
◎ The organisms found are derived from other surfaces, especially the tongue as a result of
oral removal forces (saliva and GCF flow, chewing, oral hygiene).
◎ The microbial profile of saliva (in particular, the level of mutans streptococci and/or
lactobacilli) has been used as an indicator of the caries susceptibility of an individual, and
commercially-available kits for their culture are available.
◎ People with high counts of these potentially cariogenic bacteria are considered to be ‘at-
risk’, and can be targeted for intense oral hygiene, antimicrobial therapy and dietary
counselling.
53. TEETH
◎ The microbial community associated with teeth is referred to as dental plaque. Its
composition varies at each tooth surface due to the local environmental conditions .
◎ Plaque is described on the basis of the sampling site by terms such as smooth surface,
approximal, fissure, or gingival crevice plaque, while the terms supragingival and
subgingival plaque are used to describe samples taken above or below the gum margin,
respectively.
◎ Gram positive rods and filaments (mainly Actinomyces species) are among the major
groups of bacteria cultured from plaque.
◎ Mutans streptococci and members of the mitis- and anginosus- groups of streptococci are
found in highest numbers on teeth.
54. METABOLISM OF ORAL BACTERIA
◎ The persistence of the resident oral microbiota is dependent on the ability of microbes to
attach to oral surfaces, obtain nutrients and multiply.
◎ The pattern of metabolism is closely related to whether the resident microbiota displays a
pathogenic or commensal relationship with the host.
55. CARBOHYDRATE METABOLISM
◎ Most attention has been paid to the metabolism of carbohydrates because of the
relationship between dietary sugars, acid production and dental caries.
◎ Sucrose (a disaccharide of glucose and fructose) is the most widely used dietary
sweetening agent, and can be:
1. Broken down by extracellular bacterial invertases (α-glucosidases) and the resultant
glucose and fructose molecules taken up directly by bacteria.
2. Transported intact as the disaccharide or disaccharide phosphate, and cleaved inside
the cell by an intracellular invertase or a sucrose phosphate hydrolase.
3. Used extracellularly by glycosyltransferases. Glucosyltransferases (GTF) produce
both soluble and insoluble glucans (with a release of fructose), which are important
in biofilm maturation and in the consolidation of bacterial attachment to teeth.
Fructosyltransferases (FTF) produce fructans (and liberate glucose), which can be
metabolised by other microorganisms
56.
57.
58. SUGAR TRANSPORT AND ACID
PRODUCTION
◎ All substrates have to be transported across the cytoplasmic membrane and into the
bacterial cell if they are to be used for biomass production or as an energy source. Oral
bacteria can transport carbohydrates by:
1. The phosphoenolpyruvate phosphotransferase (PEP-PTS) transport system
2. The multiple sugar metabolism (Msm) system
3. A glucose permease
59. ◎ Once sugars have been transported into the
bacterial cell, they can be used either in anabolic
pathways to generate biomass, or they can be
broken down to organic acids to generate energy.
Bacteria catabolise sugars by glycolysis to
pyruvate; the fate of pyruvate will depend on the
particular organism and the availability of oxygen.
◎ Most oral bacteria metabolise pyruvate
anaerobically to organic acids.
◎ Oral streptococci convert pyruvate to lactate by
lactate dehydrogenase when sugars are in excess,
whereas formate, acetate and ethanol are the
products of metabolism by mutans streptococci
and S. sanguinis (but not S. salivarius) under
carbohydrate limitation.
◎ Other bacterial genera produce acetate, butyrate,
propionate, and formate as primary products of
metabolism.
60. ACID TOLERANCE AND ADAPTATION TO
LOW PH
◎ Microbial survival in acidic environments
depends on the ability of a cell to maintain
intracellular pH homeostasis. The mechanisms by
which S. mutans achieves this include:
• proton extrusion via membrane associated,
proton translocating ATP synthase
• acid end-product efflux.
◎ These mechanisms ensure that the intracellular
pH remains higher (i.e., more alkaline) than that
of the external environment during acid
production. Acid tolerant organisms such as
mutans streptococci and lactobacilli have higher
levels of ATP synthase activity, and the pH
optimum for their activity is lower than for less
tolerant species such as S. sanguinis or A.
naeslundii.
61. BENEFITS OF THE ORAL MICROBIOTA
◎ Humans have coevolved with these resident microbes, and it is clear that this is a genuinely
mutualistic relationship.
◎ The host provides a warm and nutritious environment for microbial growth, whereas evidence has
emerged to show that the natural microbial residents are essential for the normal development of the
physiology, nutrition and defences of the host.
62. COLONISATION RESISTANCE
◎ One of the main beneficial functions of the oral
microbiota is its ability to prevent colonisation by
exogenous (and often pathogenic) microorganisms.
This property, termed ‘colonisation resistance', is
because of resident microorganisms being more
effective at:
1. Attachment to host receptors;
2. Competition for endogenous nutrients;
3. Creating unfavorable conditions to discourage
attachment and retard multiplication of
invading organisms; and
4. Producing antagonistic substances (hydrogen
peroxide, bacteriocins, etc.), which are
inhibitory to exogenous microbes.
63. WAYS TO BOOST COLONISATION RESISTANCE
◎ Prebiotics are molecules that stimulate
the growth and/or activity of those
members of the resident microbiota that
contribute to the well-being of their
host.
◎ Prebiotics such as non-digestible fibre
compounds (e.g., inulin, oligofructose)
have been delivered to the
gastrointestinal tract to stabilise the
composition and boost the metabolism
of the gut microbiota, especially that of
beneficial bifidobacteria and
lactobacilli.
◎ Probiotics are live microorganisms, typically
bifidobacteria and lactobacilli, that are
claimed to provide health benefits when
consumed. They can be consumed in dairy
products such as yoghurts, and most
applications are again targeted at the gut
microbiota. Commonly claimed benefits of
probiotics include the decrease of potentially
pathogenic gastrointestinal microorganisms,
the reduction of gastrointestinal discomfort,
the strengthening of the immune system and
the recovery of the intestinal microbiota in
subjects who have received antibiotic
treatment or who have suffered a gastric
illness.
64. HOST-MICROBE CROSS-TALK
◎ The host is able to detect microorganisms, and has evolved systems to tolerate beneficial
resident microorganisms without initiating a damaging inflammatory response, while also
being able to mount an efficient defence against pathogens. The attachment of bacteria to
specific receptors on host cells can trigger substantial changes in gene expression in both the
prokaryotic and eukaryotic cells.
◎ The host has developed strategies to distinguish between commensal and pathogenic bacteria.
Certain oral streptococci have been shown to suppress epithelial cell inflammatory responses
by functional modulation of immunity via Toll-like receptor expression and signalling, and
also by suppressing inflammatory responses by inhibiting activation of NFĸB or by increasing
the secretion of antiinflammatory cytokines, such as interleukin-10 (IL-10).
◎ Beneficial oral streptococci may also actively stimulate beneficial pathways in epithelial cells,
including type I and II interferon responses, promote wound healing, enhance mucin
production, and induce positive effects on then cytoskeleton.
Editor's Notes
Although the mouth is similar to other ecosystems in the digestive tract in having mucosal surfaces for microbial colonization,
Such sites on the tongue can also have a low redox potential, which enables obligatory anaerobic bacteria to grow. . Indeed, the tongue may act as a reservoir for some of the Gram-negative anaerobes.
Saliva is mainly composed of water (99%) plus proteins (0.3%), inorganic molecules (0.2%), lipids and hormones.
‘defender of the oral cavity’.
Saliva plays a fundamental role in maintaining oral health, being involved in lubrication, food clearance and buffering of microbial acids. It reduces demineralisation and
promotes remineralisation of dental tissues. Saliva promotes the attachment and growth of selected microorganisms, as well as delivering components of both the innate and adaptive host response to restrict colonisation by other microbes.
The increased production of GCF during disease is associated with a rise in the pH of the periodontal pocket from approximately 6.90 in health to between 7.25 and 7.75 during inflammation in gingivitis and periodontal disease.
Many bacteria from subgingival plaque are proteolytic and interact synergistically to break down the host proteins and glycoprotein's to provide peptides, amino acids and carbohydrates for growth.
Despite the easy access of the mouth to air with an oxygen concentration of approximately 20%, it is perhaps surprising that the oral microflora comprises few, if any, truly aerobic species.
The majority of organisms are either facultatively anaerobic or obligately anaerobic .
Differences have been found between the Eh of the gingival crevice in health and disease.
Thus, plaque will be suitable for the growth of bacteria with a range of oxygen tolerances. The redox potential at various depths will be influenced by the metabolism of the organisms present and the ability of gases to diffuse in and out of plaque.
The highest pH is found on the palate (mean pH 7.34 0.38) and the lowest on the buccal mucosa (mean Ph 6.28 0.36).
The difference in source of endogenous nutrients is one of the reasons for the variation in the microflora of the gingival crevice compared with other oral sites .
Host cell-pattern recognition receptors (e.g., Toll like receptors) can recognise microbe-associated molecular patterns (e.g., lipopolysaccharide, lipoteichoic acid) and activate multiple signalling pathways, many of which converge on nuclear factor kappa-lightchain-enhancer of activated B cells (NFĸB).