The document discusses the periodontal ligament (PDL), which is a specialized connective tissue that surrounds tooth roots and attaches them to the alveolar bone. It provides definitions of the PDL, describes its development, structure, cellular components, principal fibers, blood supply, and functions. The PDL maintains the space between the root and bone despite forces on the teeth and is composed of fibroblasts, extracellular fibers and ground substance that connect the cementum and alveolar bone. It summarizes the key anatomical and functional aspects of the PDL.
This document provides an overview of the periodontal ligament (PDL), including its development, cells, extracellular components, fiber groups, and structures. The PDL is a specialized connective tissue that attaches teeth to alveolar bone. It contains fibroblasts that secrete collagen fibers, along with blood vessels, nerves, and progenitor cells. The principal fiber groups resist various forces on teeth. The PDL allows teeth to withstand chewing forces through its extracellular matrix and continual remodeling by synthetic and resorptive cells.
This document provides an overview of the anatomy, histology, development and clinical implications of alveolar bone. It describes the components and cellular makeup of bone, including osteoblasts, osteocytes and osteoclasts. It explains that the alveolar process develops with tooth eruption and is resorbed after tooth loss. Factors that regulate bone formation and resorption are discussed. The document also outlines how alveolar bone is affected by tooth loss, orthodontic forces and non-functioning teeth.
This document provides an overview of cementum, the calcified tissue that forms the outer covering of tooth roots. It discusses the development, composition, histology, classification, and functions of cementum. Cementum begins forming at the cementoenamel junction and extends to the root apex. It is made up of inorganic hydroxyapatite and organic collagen fibers. Cementum provides a medium for periodontal ligament attachment and protects underlying dentin, helping to maintain tooth integrity under forces. It is capable of continuous deposition to repair damage or resorption on root surfaces.
The periodontal ligament is a dense fibrous tissue that connects teeth to the alveolar bone. It is composed primarily of collagen fibers arranged in bundles and a ground substance containing cells, blood vessels and nerves. The collagen fibers provide structural support and allow the teeth to withstand functional forces. Fibroblasts are the main cell type and are responsible for collagen synthesis and remodeling. Blood vessels supply the ligament with nutrients. The periodontal ligament functions to attach teeth to the alveolar bone and helps maintain the teeth in their proper functional positions.
The dentogingival junction is the region where the tooth is attached to the gingiva. It initially forms with the emergence of the tooth into the oral cavity, with the enamel covered by epithelium. Over time, the junction shifts apically as the epithelium separates from the enamel surface in a process called passive eruption. The junctional epithelium, which is more permeable, eventually attaches at the cementoenamel junction. In unhealthy conditions, the junction and sulcus can shift further onto the root surface, forming a pathological periodontal pocket.
The document discusses the alveolar bone, including its definition, components, development, structure, clinical applications, and appearance on x-rays. It notes that the alveolar bone contains the tooth sockets and supports the teeth. The alveolar bone proper surrounds the tooth root and is perforated by Volkmann's canals. The supporting alveolar bone consists of cortical plates and spongy bone between the plates and alveolar bone proper. The alveolar bone undergoes remodeling and modeling during tooth movement and in response to functional forces.
The document discusses the periodontal ligament (PDL), which is a specialized connective tissue that surrounds tooth roots and attaches them to the alveolar bone. It provides definitions of the PDL, describes its development, structure, cellular components, principal fibers, blood supply, and functions. The PDL maintains the space between the root and bone despite forces on the teeth and is composed of fibroblasts, extracellular fibers and ground substance that connect the cementum and alveolar bone. It summarizes the key anatomical and functional aspects of the PDL.
This document provides an overview of the periodontal ligament (PDL), including its development, cells, extracellular components, fiber groups, and structures. The PDL is a specialized connective tissue that attaches teeth to alveolar bone. It contains fibroblasts that secrete collagen fibers, along with blood vessels, nerves, and progenitor cells. The principal fiber groups resist various forces on teeth. The PDL allows teeth to withstand chewing forces through its extracellular matrix and continual remodeling by synthetic and resorptive cells.
This document provides an overview of the anatomy, histology, development and clinical implications of alveolar bone. It describes the components and cellular makeup of bone, including osteoblasts, osteocytes and osteoclasts. It explains that the alveolar process develops with tooth eruption and is resorbed after tooth loss. Factors that regulate bone formation and resorption are discussed. The document also outlines how alveolar bone is affected by tooth loss, orthodontic forces and non-functioning teeth.
This document provides an overview of cementum, the calcified tissue that forms the outer covering of tooth roots. It discusses the development, composition, histology, classification, and functions of cementum. Cementum begins forming at the cementoenamel junction and extends to the root apex. It is made up of inorganic hydroxyapatite and organic collagen fibers. Cementum provides a medium for periodontal ligament attachment and protects underlying dentin, helping to maintain tooth integrity under forces. It is capable of continuous deposition to repair damage or resorption on root surfaces.
The periodontal ligament is a dense fibrous tissue that connects teeth to the alveolar bone. It is composed primarily of collagen fibers arranged in bundles and a ground substance containing cells, blood vessels and nerves. The collagen fibers provide structural support and allow the teeth to withstand functional forces. Fibroblasts are the main cell type and are responsible for collagen synthesis and remodeling. Blood vessels supply the ligament with nutrients. The periodontal ligament functions to attach teeth to the alveolar bone and helps maintain the teeth in their proper functional positions.
The dentogingival junction is the region where the tooth is attached to the gingiva. It initially forms with the emergence of the tooth into the oral cavity, with the enamel covered by epithelium. Over time, the junction shifts apically as the epithelium separates from the enamel surface in a process called passive eruption. The junctional epithelium, which is more permeable, eventually attaches at the cementoenamel junction. In unhealthy conditions, the junction and sulcus can shift further onto the root surface, forming a pathological periodontal pocket.
The document discusses the alveolar bone, including its definition, components, development, structure, clinical applications, and appearance on x-rays. It notes that the alveolar bone contains the tooth sockets and supports the teeth. The alveolar bone proper surrounds the tooth root and is perforated by Volkmann's canals. The supporting alveolar bone consists of cortical plates and spongy bone between the plates and alveolar bone proper. The alveolar bone undergoes remodeling and modeling during tooth movement and in response to functional forces.
The document discusses aging changes that occur in the periodontium. Key points:
- With aging, the gingival epithelium thickens due to acanthosis. Connective tissue ridges become more prevalent in young individuals while papillae predominate in old individuals.
- The periodontal ligament has greater elastic fibers, decreased vascularity and cellular elements, and altered collagen with aging. Alveolar bone shows increased osteoporosis and irregular surfaces facing the ligament.
- Subgingival plaque in older adults contains more enteric rods and pseudomonads, and increased pathogens like P. gingivalis. Periodontitis is associated with increased risk of conditions like diabetes, coronary
This document provides an overview of cementum, the mineralized tissue that covers tooth roots. It defines cementum and discusses its development, physical and chemical characteristics, classification, cells, functions, and involvement in periodontal disease. Cementum is composed of collagen fibers embedded in mineralized matrix. It provides attachment for periodontal ligament fibers and aids in tooth function and repair. The document also examines cementum at the microscopic level and various proteins and cells involved in its formation and remodeling.
The document discusses the alveolar bone, including its definition, composition, structure, cells, blood supply, and changes associated with orthodontic forces. It notes that alveolar bone surrounds and supports the teeth sockets. It is composed primarily of inorganic minerals and collagen. Microscopically, it contains osteons arranged in concentric lamellae around Haversian canals. Osteoblasts build bone while osteoclasts resorb it, maintaining a constant state of remodeling. The alveolar bone has a rich blood supply from the superior and inferior alveolar arteries and drains via lymph vessels. Orthodontic forces induce changes in the bone's morphology and turnover.
Cementum is the mineralized connective tissue covering tooth roots. It has several functions including anchoring collagen fibers from the periodontal ligament to provide attachment between the tooth and bone. Cementum can be classified based on its location, cellularity, fiber content, and other characteristics. It plays roles in adaptation, repair, and maintaining the periodontium. The cemento-enamel junction describes the interface between cementum and enamel at the cervical portion of the tooth root.
This document provides an overview of bone histology and development. It discusses that bone is a specialized mineralized connective tissue that can be divided into compact and cancellous bone microscopically. Bone develops through either endochondral or intramembranous ossification. The key cells involved are osteoblasts, which form new bone, and osteoclasts, which resorb bone. Bone is remodeled throughout life by the balanced actions of these cells.
This document provides an overview of cementum, including:
- Its physical characteristics, composition, classification, and formation process (cementogenesis).
- The cells involved in cementum formation and maintenance, including cementoblasts and cementocytes.
- Its locations and junctions with other tissues like enamel and dentin.
- The functions of cementum in anchoring teeth, adaptation, and repair.
- Some developmental anomalies and abnormalities that can affect cementum.
The document discusses various age-related changes that occur in oral tissues. It describes changes at the macroscopic, microscopic, and cellular levels in tissues like enamel, dentin, pulp, cementum, periodontal ligament, alveolar bone, gingiva and salivary glands. With increasing age, the oral tissues show signs of wear and tear like cracks, discoloration and loss of elasticity. There are also changes in vascularity, cellularity and thickness of various tissues. The rate of tissue turnover reduces with aging affecting the structure and function of oral tissues.
Alveolar bone is the specialized bone that forms the sockets for teeth in the maxilla and mandible. It consists of alveolar bone proper surrounding the tooth root, supporting alveolar bone made of cortical plates and spongy bone, and bundle bone where periodontal ligament fibers insert. Osteoblasts build bone matrix while osteoclasts resorb it, allowing remodeling. With age, alveolar bone thins with wider marrow spaces and more fragile trabeculae, leading the alveolar crest to slope down distally as teeth tilt mesially.
This document provides information on cementum, including its definition, physical characteristics, chemical composition, formation (cementogenesis), classification, functions, anomalies, and clinical considerations. Cementum is the mineralized tissue covering tooth roots. It is softer than dentin and lacks enamel's luster. Cementum formation involves acellular and cellular stages. Cementum attaches the periodontal ligament fibers to the tooth root and allows for tooth repair. Abnormalities include hypercementosis, ankylosis, and cementomas. Cementum is an important part of the periodontium that aids in tooth attachment and repair.
The document discusses the periodontal ligament (PDL), which is the soft connective tissue that surrounds tooth roots and attaches cementum to alveolar bone. It defines PDL and describes its extent, average width, development from the dental follicle, orientation of collagen fibers, cellular elements including fibroblasts, cementoblasts, osteoblasts, and epithelial rests of Mallassez. The document also covers the biochemical composition and ground substance of PDL, as well as its blood supply, nerve supply, age-related changes, and role in healing after periodontal surgery.
Alveolar bone forms tooth sockets and provides attachment for the periodontal ligament. It is composed of outer cortical and inner cancellous bone. Osteoblasts form bone matrix containing collagen fibers and hydroxyapatite crystals. Osteoclasts resorb bone. Bone is remodeled through the balanced actions of osteoblasts and osteoclasts, regulated by hormones and growth factors.
The periodontal ligament (PDL) is a soft connective tissue that surrounds tooth roots and attaches them to the alveolar bone in the jaw. It ranges from 0.15-0.38mm in width and is narrowest at the mid-root level. The PDL contains principal collagen fibers, blood vessels, nerves and cells that allow it to absorb forces and remodel throughout life. Diseases can widen the PDL space and disrupt its fibers. The document discusses the development, structure, functions and clinical implications of the PDL.
The document discusses the dentogingival junction and junctional epithelium. It begins with an introduction and overview of the three zones of gingival epithelium. It then covers the historical aspects and development of the junctional epithelium. The structure of the junctional epithelium is described including its anatomical features, epithelial attachment apparatus involving hemidesmosomes, and dynamic aspects like rapid turnover. The permeability and various functions of the junctional epithelium are also summarized.
The document summarizes the anatomy and structures of the gingiva. It describes the marginal gingiva, gingival sulcus, attached gingiva, interdental gingiva, and mucogingival junction. It discusses the functions of the gingiva in protecting tissues, obtaining shape with tooth eruption, and resisting forces. The document also examines age-related changes to the gingiva and studies on the width of attached gingiva needed for periodontal health.
This document provides an overview of dentin, including:
- A brief history of discoveries related to dentin structure.
- Dentinogenesis, the process of dentin formation carried out by odontoblasts. Primary dentin formation beneath the enamel and root dentin formation are described.
- The physical properties, chemical composition, and structural components of dentin including dentinal tubules, predentin, peritubular and intertubular dentin.
- Features such as von Ebner's lines, lines of Schreger, and contour lines of Owen which represent incremental growth patterns in dentin.
The document discusses the peridontium and its components, which include the gingiva, periodontal ligament, cementum, and alveolar bone. It focuses on cementum, describing it as a hard connective tissue that covers tooth roots and provides attachment for collagen fibers. Cementum begins forming at the cementoenamel junction and continues to the root apex. It contains cementoblasts and cementocytes that aid in its formation and structure. Cementum comes in cellular and acellular varieties and demonstrates incremental lines from its continuous deposition over time.
This document discusses the development of the periodontium, which includes the cementum, periodontal ligament, alveolar bone, and gingiva. It describes how the tooth germ develops from the enamel organ and dental papilla through stages of growth. Root formation is induced by Hertwig's epithelial root sheath, which regulates the development of cementum, periodontal ligament, and alveolar bone through cellular differentiation and protein signaling. The periodontium develops through reciprocal interactions between the enamel organ and dental follicle mesenchyme.
The periodontal ligament is a fibrous connective tissue that attaches the tooth to the alveolar bone. It is composed of fibers, cells, blood vessels and ground substance. The fibers are arranged in bundles that provide support, resist displacement, and allow movement. The principal fiber groups include gingival fibers around the neck of the tooth and dento-alveolar fibers along the root. Blood supply comes from the superior and inferior alveolar arteries.
The periodontal ligament connects tooth roots to alveolar bone and is made up of collagen fibers, cells, blood vessels and nerves. It develops from the dental follicle and extends from the cementum to the alveolar bone. The principal collagen fibers develop in stages during eruption and establish the ligament's architecture. The periodontal ligament contains fibroblasts, osteoblasts and cementoblasts which synthesize and maintain the ligament, as well as osteoclasts and cementoclasts which resorb bone and cementum. It has a complex blood, nerve and lymphatic supply to support its functions in tooth mobility, sensation and homeostasis.
The document discusses aging changes that occur in the periodontium. Key points:
- With aging, the gingival epithelium thickens due to acanthosis. Connective tissue ridges become more prevalent in young individuals while papillae predominate in old individuals.
- The periodontal ligament has greater elastic fibers, decreased vascularity and cellular elements, and altered collagen with aging. Alveolar bone shows increased osteoporosis and irregular surfaces facing the ligament.
- Subgingival plaque in older adults contains more enteric rods and pseudomonads, and increased pathogens like P. gingivalis. Periodontitis is associated with increased risk of conditions like diabetes, coronary
This document provides an overview of cementum, the mineralized tissue that covers tooth roots. It defines cementum and discusses its development, physical and chemical characteristics, classification, cells, functions, and involvement in periodontal disease. Cementum is composed of collagen fibers embedded in mineralized matrix. It provides attachment for periodontal ligament fibers and aids in tooth function and repair. The document also examines cementum at the microscopic level and various proteins and cells involved in its formation and remodeling.
The document discusses the alveolar bone, including its definition, composition, structure, cells, blood supply, and changes associated with orthodontic forces. It notes that alveolar bone surrounds and supports the teeth sockets. It is composed primarily of inorganic minerals and collagen. Microscopically, it contains osteons arranged in concentric lamellae around Haversian canals. Osteoblasts build bone while osteoclasts resorb it, maintaining a constant state of remodeling. The alveolar bone has a rich blood supply from the superior and inferior alveolar arteries and drains via lymph vessels. Orthodontic forces induce changes in the bone's morphology and turnover.
Cementum is the mineralized connective tissue covering tooth roots. It has several functions including anchoring collagen fibers from the periodontal ligament to provide attachment between the tooth and bone. Cementum can be classified based on its location, cellularity, fiber content, and other characteristics. It plays roles in adaptation, repair, and maintaining the periodontium. The cemento-enamel junction describes the interface between cementum and enamel at the cervical portion of the tooth root.
This document provides an overview of bone histology and development. It discusses that bone is a specialized mineralized connective tissue that can be divided into compact and cancellous bone microscopically. Bone develops through either endochondral or intramembranous ossification. The key cells involved are osteoblasts, which form new bone, and osteoclasts, which resorb bone. Bone is remodeled throughout life by the balanced actions of these cells.
This document provides an overview of cementum, including:
- Its physical characteristics, composition, classification, and formation process (cementogenesis).
- The cells involved in cementum formation and maintenance, including cementoblasts and cementocytes.
- Its locations and junctions with other tissues like enamel and dentin.
- The functions of cementum in anchoring teeth, adaptation, and repair.
- Some developmental anomalies and abnormalities that can affect cementum.
The document discusses various age-related changes that occur in oral tissues. It describes changes at the macroscopic, microscopic, and cellular levels in tissues like enamel, dentin, pulp, cementum, periodontal ligament, alveolar bone, gingiva and salivary glands. With increasing age, the oral tissues show signs of wear and tear like cracks, discoloration and loss of elasticity. There are also changes in vascularity, cellularity and thickness of various tissues. The rate of tissue turnover reduces with aging affecting the structure and function of oral tissues.
Alveolar bone is the specialized bone that forms the sockets for teeth in the maxilla and mandible. It consists of alveolar bone proper surrounding the tooth root, supporting alveolar bone made of cortical plates and spongy bone, and bundle bone where periodontal ligament fibers insert. Osteoblasts build bone matrix while osteoclasts resorb it, allowing remodeling. With age, alveolar bone thins with wider marrow spaces and more fragile trabeculae, leading the alveolar crest to slope down distally as teeth tilt mesially.
This document provides information on cementum, including its definition, physical characteristics, chemical composition, formation (cementogenesis), classification, functions, anomalies, and clinical considerations. Cementum is the mineralized tissue covering tooth roots. It is softer than dentin and lacks enamel's luster. Cementum formation involves acellular and cellular stages. Cementum attaches the periodontal ligament fibers to the tooth root and allows for tooth repair. Abnormalities include hypercementosis, ankylosis, and cementomas. Cementum is an important part of the periodontium that aids in tooth attachment and repair.
The document discusses the periodontal ligament (PDL), which is the soft connective tissue that surrounds tooth roots and attaches cementum to alveolar bone. It defines PDL and describes its extent, average width, development from the dental follicle, orientation of collagen fibers, cellular elements including fibroblasts, cementoblasts, osteoblasts, and epithelial rests of Mallassez. The document also covers the biochemical composition and ground substance of PDL, as well as its blood supply, nerve supply, age-related changes, and role in healing after periodontal surgery.
Alveolar bone forms tooth sockets and provides attachment for the periodontal ligament. It is composed of outer cortical and inner cancellous bone. Osteoblasts form bone matrix containing collagen fibers and hydroxyapatite crystals. Osteoclasts resorb bone. Bone is remodeled through the balanced actions of osteoblasts and osteoclasts, regulated by hormones and growth factors.
The periodontal ligament (PDL) is a soft connective tissue that surrounds tooth roots and attaches them to the alveolar bone in the jaw. It ranges from 0.15-0.38mm in width and is narrowest at the mid-root level. The PDL contains principal collagen fibers, blood vessels, nerves and cells that allow it to absorb forces and remodel throughout life. Diseases can widen the PDL space and disrupt its fibers. The document discusses the development, structure, functions and clinical implications of the PDL.
The document discusses the dentogingival junction and junctional epithelium. It begins with an introduction and overview of the three zones of gingival epithelium. It then covers the historical aspects and development of the junctional epithelium. The structure of the junctional epithelium is described including its anatomical features, epithelial attachment apparatus involving hemidesmosomes, and dynamic aspects like rapid turnover. The permeability and various functions of the junctional epithelium are also summarized.
The document summarizes the anatomy and structures of the gingiva. It describes the marginal gingiva, gingival sulcus, attached gingiva, interdental gingiva, and mucogingival junction. It discusses the functions of the gingiva in protecting tissues, obtaining shape with tooth eruption, and resisting forces. The document also examines age-related changes to the gingiva and studies on the width of attached gingiva needed for periodontal health.
This document provides an overview of dentin, including:
- A brief history of discoveries related to dentin structure.
- Dentinogenesis, the process of dentin formation carried out by odontoblasts. Primary dentin formation beneath the enamel and root dentin formation are described.
- The physical properties, chemical composition, and structural components of dentin including dentinal tubules, predentin, peritubular and intertubular dentin.
- Features such as von Ebner's lines, lines of Schreger, and contour lines of Owen which represent incremental growth patterns in dentin.
The document discusses the peridontium and its components, which include the gingiva, periodontal ligament, cementum, and alveolar bone. It focuses on cementum, describing it as a hard connective tissue that covers tooth roots and provides attachment for collagen fibers. Cementum begins forming at the cementoenamel junction and continues to the root apex. It contains cementoblasts and cementocytes that aid in its formation and structure. Cementum comes in cellular and acellular varieties and demonstrates incremental lines from its continuous deposition over time.
This document discusses the development of the periodontium, which includes the cementum, periodontal ligament, alveolar bone, and gingiva. It describes how the tooth germ develops from the enamel organ and dental papilla through stages of growth. Root formation is induced by Hertwig's epithelial root sheath, which regulates the development of cementum, periodontal ligament, and alveolar bone through cellular differentiation and protein signaling. The periodontium develops through reciprocal interactions between the enamel organ and dental follicle mesenchyme.
The periodontal ligament is a fibrous connective tissue that attaches the tooth to the alveolar bone. It is composed of fibers, cells, blood vessels and ground substance. The fibers are arranged in bundles that provide support, resist displacement, and allow movement. The principal fiber groups include gingival fibers around the neck of the tooth and dento-alveolar fibers along the root. Blood supply comes from the superior and inferior alveolar arteries.
The periodontal ligament connects tooth roots to alveolar bone and is made up of collagen fibers, cells, blood vessels and nerves. It develops from the dental follicle and extends from the cementum to the alveolar bone. The principal collagen fibers develop in stages during eruption and establish the ligament's architecture. The periodontal ligament contains fibroblasts, osteoblasts and cementoblasts which synthesize and maintain the ligament, as well as osteoclasts and cementoclasts which resorb bone and cementum. It has a complex blood, nerve and lymphatic supply to support its functions in tooth mobility, sensation and homeostasis.
This document summarizes a presentation on the periodontal ligament given by Dr. Abhishek Gakhar. It discusses the structure, development, constituents including cells, fibers and blood/nerve supply of the periodontal ligament. The functions of the periodontal ligament and its clinical correlations are also reviewed. Diagrams illustrate the fiber groups and cells found in the periodontal ligament.
The periodontal ligament is a complex connective tissue that surrounds the tooth root and connects it to the alveolar bone. It is composed of collagen fibers, cells like fibroblasts and cementoblasts, blood vessels and nerves. The PDL develops from the dental follicle during root formation and ranges in width from 0.15-0.38mm. It contains principal fibers that extend obliquely from cementum to bone and adapt to functional changes in teeth. The PDL maintains homeostasis between the hard tissues of cementum and bone through regulatory molecules and cells.
This document provides information on the connective tissue of the periodontium. It defines the periodontium and describes its four main components - gingiva, periodontal ligament, cementum, and alveolar bone. It then discusses the structure and components of gingival connective tissue, periodontal ligament, and the extracellular matrix. Key cell types and fibers are described. In conclusion, the connective tissue of the periodontium plays an important role in supporting teeth and maintaining periodontal health.
The dental pulp is the soft connective tissue contained within the tooth. It originates from neural crest cells that migrate and condense around ectomesenchymal cells to form the dental papilla during development. The pulp contains odontoblasts, fibroblasts, undifferentiated cells and defense cells. It has a histological structure with outer odontoblastic, cell-free and inner cell-rich zones. The pulp functions to provide nutrition, sensation, defense and formation/protection of dentin. In aging teeth, the pulp undergoes changes like fewer cells, fibrosis, vascular changes and calcifications that decrease its functions over time.
This document provides an overview of the periodontal ligament (PDL). It describes the PDL's extent, shape, width and cellular components. The PDL contains principal collagen fibers that connect cementum to alveolar bone in different orientations. It is made up of fibroblasts, osteoblasts, cementoblasts and other cells. The PDL helps anchor teeth, withstand forces from chewing and allows limited movement.
The periodontal ligament is a complex connective tissue that connects teeth to the alveolar bone. It contains fibroblasts, cementoblasts, osteoblasts, osteoclasts and epithelial rests of Malassez. The fibroblasts are the predominant cells and produce collagen fibers that develop into principal fiber bundles. The periodontal ligament allows for adaptation during function by remodeling its collagen fibers and allows movement within the periodontal space. It develops from the dental follicle prior to tooth eruption and contains stem cells that can differentiate into cementoblasts, osteoblasts or fibroblasts.
The document provides an overview of the periodontal ligament (PDL). It discusses the development, cells, extracellular substances like fibers and ground substance, structures present, and functions of the PDL. The PDL is a soft connective tissue that surrounds tooth roots and attaches them to the alveolar bone. It is derived from the dental follicle during root formation and contains fibroblasts, cementoblasts, osteoblasts and other cells. Collagen fibers are the main component and help attach the PDL to cementum and bone. The PDL acts to support teeth, absorb chewing forces, and allow limited movement.
The document provides an overview of dental pulp, including its:
1. Development from the dental papilla during the 8th week of gestation.
2. Anatomy, with the coronal pulp in the crown and radicular pulp in the root canal. Primary pulp has a larger chamber relative to crown size compared to permanent pulp.
3. Histology consisting of an odontoblast layer, cell-free zone, cell-rich zone, and pulp core containing blood vessels and nerves.
4. Main cell types - odontoblasts, fibroblasts, undifferentiated mesenchymal cells, and defense cells like macrophages, mast cells, and lymphocytes.
5.
Periodontal ligament dr. sherif hassan sherifsayed65
The periodontal ligament is a thin connective tissue that fills the space between the root and alveolar bone. It ranges from 0.15-0.38mm thick and is thinner in the middle of the root and thicker at the crest and apex. The periodontal ligament supports the tooth, allows it to withstand forces, and acts as a cushion to distribute forces to the bone. It contains sensory nerves for pain and touch, and receives a blood supply for nutrition. Fibroblasts form collagen fibers that attach to cementum and bone, providing support. The periodontal ligament also plays roles in tooth eruption, remodeling, and protection.
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The periodontal ligament is a connective tissue that connects the cementum of teeth to the alveolar bone. It contains fibroblasts that form collagen fibers, as well as blood vessels, nerves, and other cell types. The periodontal ligament provides supportive, sensory, nutritive, and protective functions to help anchor teeth and maintain the periodontium. It transmits forces during chewing and contains nerve fibers that detect pressure and pain.
This document discusses the biology of tooth movement. It begins by classifying tooth movement into physiological, pathological, and orthodontic categories. It then discusses the historical studies on tooth movement dating back to the early 1900s. The bulk of the document describes the relevant biological structures - cementum, periodontal ligament, alveolar bone, and their cells and composition. It explains the fiber groups within the periodontal ligament. Finally, it discusses the biological events and tissue reactions that occur during orthodontic tooth movement.
The dental pulp is loose connective tissue located in the center of the tooth that contains blood vessels, nerves, and cells like odontoblasts. It has formative, nutritive, protective, and defensive functions. Over time, the pulp undergoes changes like decreased size and vascularity, increased calcification in the form of pulp stones or diffuse deposits, and reduced vitality.
The dental pulp is loose connective tissue located within the tooth. It can be divided into the coronal pulp within the crown and radicular pulp within the root. The pulp contains cellular elements like odontoblasts, fibroblasts, and defensive cells, as well as neurovascular elements. With age, the size of the pulp decreases as secondary dentin is deposited. The number of cells and vascularity also decrease with age. Accessory canals may form due to developmental processes or resorption of tissue during aging. The pulp provides nutrients and defenses to the tooth.
Epithelial tissue, also known as the epithelium, is one of the four tissues found in the human body. It exists in various parts of the body, such as our digestive system, outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs.
Histology
Junqueira’s Basic Histology Text and Atlas, 15th Ed
This document provides an outline and overview of a lecture on connective tissues. It begins with objectives and an introduction to connective tissues, describing their general features and functions. It then discusses the cells and extracellular matrix components of connective tissue, including fibers and ground substance. Several types of connective tissues are classified and described, including loose connective tissue, dense connective tissue, cartilage, and bone. Clinical correlations regarding conditions like Marfan syndrome are also presented.
Travel Clinic Cardiff: Health Advice for International TravelersNX Healthcare
Travel Clinic Cardiff offers comprehensive travel health services, including vaccinations, travel advice, and preventive care for international travelers. Our expert team ensures you are well-prepared and protected for your journey, providing personalized consultations tailored to your destination. Conveniently located in Cardiff, we help you travel with confidence and peace of mind. Visit us: www.nxhealthcare.co.uk
DECLARATION OF HELSINKI - History and principlesanaghabharat01
This SlideShare presentation provides a comprehensive overview of the Declaration of Helsinki, a foundational document outlining ethical guidelines for conducting medical research involving human subjects.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
The skin is the largest organ and its health plays a vital role among the other sense organs. The skin concerns like acne breakout, psoriasis, or anything similar along the lines, finding a qualified and experienced dermatologist becomes paramount.
Kosmoderma Academy, a leading institution in the field of dermatology and aesthetics, offers comprehensive courses in cosmetology and trichology. Our specialized courses on PRP (Hair), DR+Growth Factor, GFC, and Qr678 are designed to equip practitioners with advanced skills and knowledge to excel in hair restoration and growth treatments.
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.
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3. Introduction
Development
Homeostasis
Contents of PDL
Functions
Age changes
Clinical considerations
Conclusion
Refferences
3
4. PDL is an connective tissue
organ, covered by epithelium
which attaches the teeth to
the bones of jaw.
And it provides continuously
adapting apparatus for support
of the teeth during function.
4
5. The term ligament is used because of it is a complex
soft connective tissue, connecting two mineralized
tissues.
Definition:
According to Caranza& Bernard:
“The periodontal ligament is the connective tissue that
surrounds the root & connects it to the bone. it is
continuous with the connective tissue of gingiva &
communicates with the marrow spaces through
vascular channels in the bone.
According to Berkovitz, Holland & Moxham:
“It is the dense fibrous connective tissue that
occupies the periodontal space between the root of
the tooth & the alveolus. It is derived from the
dental follicle above the alveolar crest is continuous
with the connective tissues of gingiva; at the apical
foramen it is continuous with the dental pulp.
5
7. Thickness of the PDL
0.15 to 0.38mm
Radiographically
0.4 to 1.5 mm
It is thinnest around the middle
third of the root, with an hour
glass appearance.
Thickness of the PDL decreases
with age.
Young adult - 0.21mm
Mature adult - 0.18mm
Old adult - 0.15mm
7
8. Develops from Dental Follicle.
Development of PDL begins with root formation.
Developing Hertwig`s epithelial root sheath separates
Dental papilla & dental follicle.
8
9. Dental follicle has 2 types of
cells.
Dental follicle proper
Perifollicularmesenchyme
9
10. As the root formation continues, cells in the peri
follicular mesenchyme gain their polarity, cellular
volume & become widely separated
Actively synthesize & deposit collagen fibrils and
glycoprotiens in developing PDL
Type I collagen is secreted
Assembles as collagen bundles on the bone and
cememtum surface
Establish continuity across the ligament space
10
12. Development of Principal Fibers:
Periodontal fibers develop from mesenchymal cells of the PDL.
First formed fibers are Alveolar crest fibers.
Fibroblast in the coronal third, align in oblique direction to the
tooth long axis and start secreting alveolar crest group of
fibers.
12
13. Microfibrils from cementum & alveolar bone grow towards
center to meet, intertwine and fuse to form remaining
groups of fibers.
At the time of occulusal contact alveolar crest group and
horizontal group fibers are fully developed. Oblique &
Apilcal groups are under developing state.
13
15. Periodontal ligament maintains its width more or
less overtime.
This is because of molecules secreted by
different cells in the PDL.
These molecules can regulate the extent of
mineralization of the surrounding hard tissues
like bone and cementum.
These factors can prevent the fusion of the root
and bone by preventing excess mineralization.
15
16. Some Factors maintaining homeostasis of PDL:
Prostaglandins : Inhibit mineralized bone nodule
formation by bone stromal cells.
Msx2 : Prevents Osteogenic differentiation of
fibroblasts by suppressing Cbfa1 (also
known as Runx2 ) transcriptional activity.
Bone sialoprotien: Balance between these contributes to &
Osteopontin the unmineralized PDL.
Matrix ‘GLA’ protein: Inhibitor of the mineralization.
Glycosaminoglycans or
RGD-cementum attachment protein
16
17. PDL has capacity to adapt to functional
changes:
Functional demand
increases
Width of PDL increases
by as much as 50%
Fiber bundle increases
in thickness
Functional demand
decreases
Narrowing of PDL
Decrease in number
and thickness of fiber
bundle
17
20. Synthetic cells:
Cells that are synthesizing proteins for secretion.
Microscopically they appear as comparatively
large cells with large vesicular nucleus with
prominent nucleoli due to increased
transcription of RNA & production of ribosomes.
And cytoplasm is also abundant, due to
increased activity of mitochondria, golgi
membrane and RER.
20
22. Osteoblasts:
Secrete bone components.
Cover the surface of the bone
Microscopic features:
Cuboidal in shape
Prominent round nucleus at
the basal end.
Abundant RER, mitochondria
and vesicles.
Basophilic due to RER
Pale juxtanuclear layer of
golgi membrane.
Microfilaments are present
beneath the cell membrane, at
the secretary surface.
22
23. Fibroblasts:
Predominant cells in PDL
Secret Fiber Components.
Mainly secret
Collagen
Elastin
Glycoprotien
Glycosaminoglycans
Matrixmetalloprotinesases (MMP`s)
Responsible for the formation and remodeling of
PDL fibers & signaling system to maintain the
width and thickness of the PDL.
23
24. Microscopic features
Fusiform in shape.
Large cells with large nucleus and one or
more prominent nucleoli.
Extensive RER Well developed golgi Complex
Abundant secretory granules containing type-
1 collagen.
Cytoplasmic extensions in secretory end that
form 3 dimensional veils which
compartmentalize collagen fibrils to fibers.
24
25. Cementoblasts:
Secrete cementum.
Arranged on the cementum.
Microscopic features:
Often indistinguishable from PDL fibroblasts.
Cuboidal in shape.
Large nucleus with One or more nucleoli.
Abundant mitochondria & less RER.
Cellular cementum secreting cells have
cytoplasmic processes and the nucleoli are
folded and irregularly shaped.
Acellular cementum secreting cells don’t have
these cytoplasmic processes.
25
27. Osteoclasts:
Responsible for bone
resorption.
Microscopic features:
Large multinucleated but
sometimes small and mono
nucleated.
Have eosinophilic cytoplasm.
Abundant cytoplasam,
mitochondria,golgicomplex, free
ribosmomes, little RER.
Plasma membrane is folded in the
resorbing side- Ruffled boarder or
Striated boarder.
Under the ruffled boarder – Clear
zone.
Resorb bone by producing highly
acidic PH .
27
29. Fibroblasts:
Show rapid degeneration of collagen by
Phagocytosis, which results in fast turnover of
collagen.
Collagen degradation is both
Extracellular
Intracellular
Normally intracellular in healthy tissues, where
there is a controlled turnover& remodeling.
Extracellular is seen in pathological conditions
where degeneration is rapid and involves whole
tissue, simultaneously.
29
30. Extracellular:
Matrix metalloprotiens (MMP`s) secreted by fibroblasts
play an important role in extracellular collagen
degradation.
Removal of fibronectin & proteoglycans on fibril surface by
Stromelysin (MMP-III)
Collagenase (MMP-I)binding
Cleavage of triple helix portion of molecules
with in the fibril
Denaturation of collagen by MMP-IV
Prteolysis of the rest of the molecule by MMP-II (Gelatinase)
& MMP-V
30
31. Intracellular:
Through Phagocytosis
Intracellulrar collagen profiles – Special cell
organells for collagen degradation
Collagenase is not involved
Lysosomal cysterine protinesases are
involved.
31
32. Phagocytosis of collagen fibrils
Banded fibril is surrounded by Electron- lucent zone
Phagosome+ lysosome Phagolysosome
Enzymic degradation of fibrils
Electronlucent zone Electon dense zone
Fibrils loss their characeristic structure
32
33. Cementoclasts:
They resembles osteoclasts and are located in
depressions in cementum resembling Howship`s
lacuna.
As cementum does not remodel, Cementoclasts
are not usually found in the ligament.
These cells only occur in some pathological
conditions, during resorption of deciduous teeth
and when regressive forces are applied on a
tooth such as orthodontic therapy.
These cells not only resorb cementum, they can
destroy dentin and enamel as well thus they are
called Odontoclasts.
33
34. Progenitor cells:
All connective tissues including PDL contain
progenitor cells that have the capacity to
undergo mitotic division.
When stimulated appropriately, these cells
undergo mitotic division and can differentiate
into fibroblast, osteoblast or cementoblast.
34
35. Epithelial cell rests of
Malassez:
These were first described by
Malassez in 1884 and are the
remnants of the epithelium of
Hertwig’s epithelial root
sheath.
They persist as networks,
strands, islands or tubule-like
structures near and parallel to
the surface of the root.
35
36. Their function is not yet clear
but they could be involved in
periodontal repair and
regeneration.
These cells may proliferate to
form cysts and tumors.
These cells may undergo
calcification to become
CEMENTICLES.
36
37. Defence cells:
Mast cells
Eosinophills
Macrophages
MAST CELLS – These are relatively small
round or oval cell having a diameter of about
12 to 15 um
Mast cells are often associated with blood
vessels .
These cells are characterized by numerous
cytoplasmic granules which frequently
obscure the small , round nucleus .
37
38. MACROPHAGES-
These are found in the ligament and are
predominantly located adjacent to blood vessels
.
The wandering type are derived from blood
monocytes has a characteristic ultrastructure
that permits it to be readily distinguished from
fibroblasts .
38
39. EOSINOPHILLS –
These are seen in the periodontal ligament .
They posses granules that consist of one or
more crystalloid structures .
These are capable of phagocytosis .
39
41. FIBERS
COLLAGEN :
The main types of collagen in the PDL are TYPE I
and TYPE III.
More than 70 % of PDL is Type I .
Type I is uniformly distributed in the ligament .
Type III collagen accounts for about 20 % of
collagen fibers, found in periphery of Sharpey’s
fiber attachments into alveolar bone.
Type IV and VII are associated with epithelial cell
rests and blood vessels.
Type XIII collagen is believed to occur within the
PDL only when ligament is fully functional .
Within each collagen bundle , subunits are
present called collagen fibrils.
41
43. PRINCIPAL PDL FIBERS :
The collagen is gathered to form bundles
approximately 5 um in diameter. These bundles
are termed as PRINCIPAL FIBERS.
These are collagenous and follow a wavy pattern
when viewed in longitudinal section.
They are thought to contribute to the regulation
of mineralization and to tissue cohesion at sites of
increased biomechanical strain.
43
44. Types of Principal fibers
Alveolar crest
Horizontal group
Oblique group
Apical group
Inter radicular group
44
45. Fiber group Origin & insertion Function
1. Alveolar crest Extend obliquely from the
cementum just beneath the
junctional epithelium to the
alveolar crest and to the fibrous
layer of the periosteum covering
the alveolar bone.
Retains tooth in the socket
Oppose lateral forces
Prevents extrusion &
intrusion of tooth. Protects
deeper periodontal
ligament structures
2. Horizontal They extend from cementum to
alveolar bone in horizontal
direction at right angles to long
axis of tooth.
Restrain lateral tooth
movements.
3.Oblique Largest group of PDL fibers.
Occupy 80-85% of root surface.
Extend from cementum in a
coronal direction obliquely to
the bone.
They bear vertical
masticatory stresses and
transform them into
tension on alveolar bone
and resist intrusive forces.
4. Apical The apical fibres radiate in a
rather irregular fashion from
cementum to the apical region
of the socket
Prevent tooth tipping Resist
luxation. Protect blood,
lymph and nerve supplies
to tooth.
5. Interradicular They fan out from the cementum
to the tooth in the furcation
areas of multirooted teeth.
Aid in resisting tipping
torquing and luxation.
45
46. SHARPEYS FIBERS:
The collagen bundles of the periodontal
ligament embedded into cementum and
alveolar bone – are called as Sharpey’s fibers.
Orientation is similar to that of adjacent
periodontal ligament bundles.
Sharpey’s fibers in Acellular cementum- fully
mineralized.
Cellular cementum & Alveolar Bone – partially
mineralized.
Few Sharpey’s fibers pass uninterruptedly
through bone of alveolar process –
Transalveolar fibers.
46
48. ELASTIN FIBERS :
There are three types of elastic fibers which
are histochemically and ultrastructurally
different.
Mature Elastic fibers
Eulanin fibers
Oxytalan fibers .
Eulanin fibers and Oxytalan fibers have been
described as immature elastic fibers.
MATURE ELASTIC FIBERS
Consist of microfibrillar component
surrounding an amorphous core of elastin
protein .
48
49. Restricted to walls of blood vessels in humans
PDL fibers do not contain mature elastin but two
immature forms are found oxytalan and eulanin
OXYTALAN FIBERS :
Are micro fibrils
Run in apico-coronal direction to bend and
attach at cervical third of root
Diameter – 0.5-2.5um
Volume – 3%
Function is unknown but they may play a role in
- supporting blood vessels of PDL.
- tooth support (abutments/
Orthodontically moved teeth)
49
50. EULANIN FIBERS:
Are bundles of microfibrils embedded in a
small amount of amorphous elastin.
An elastic meshwork has been described in
the PDL as being composed of many elastin
lamellae with peripheral oxytalan & eulanin
fibers .
Functions
- Regulate vascular flow
- Role in tooth support
- Facilitate fibroblast attachment and
migration.
50
51. RETICULAR FIBERS:
These are immature collagen fibers with
argyrophilic staining properties and are related
to basement membrane of blood vessels and
epithelial cells which lie within the periodontal
ligament.
SECONDARY FIBERS :
Represent the newly formed collagenous
elements, not yet incorporated into principal
fiber bundle.
Located between and among the principal fibers.
These are relatively non-directional and
randomly oriented.
Appear to transverse the periodontal ligament
space corono-apically and are often associated
with path of vasculature and nervous elements.
51
52. INDIFFERENT FIBER PLEXUS:
Small Collagen fibers in association with the
larger principal collagen fiber.
Run in all directions forming a plexus.
Once the tooth has erupted into clinical
occlusion such an intermediate plexus is no
longer demonstrable.
Intermediate plexus has been reinterpreted
by Sloan as representing merely an optical
effect explained entirely by the arrangement
of middle layer collagen into sheets rather
than bundles.
52
53. GROUND SUBSTANCE
The ground substance is the gel like matrix
synthesized by the fibroblast family & fills
the space between the fibers and cells.
COMPOSITION :
Consists of a biochemically complex, highly
hydrated, semisolid gel.
Water content of 70%
Glycosaminoglycan's – hyaluronic acid,
Proteoglycans( versican , decorin )
Glycoproteins -fibronectin , laminin,
vibronectin , tenascin
53
54. Glycosaminoglycans:
PROTEOGLYCANS
Large group of anionic macromolecules that
consists of a protein core to which are attached
hexose amine containing polysaccharides called
GAG chains.
1. Decorin – regulates growth of collagen fibrils.
2. Versican – binds cell surface glycoproteins to
ECM.
3. Prelecan - binds to fibronectin & helps anchor
fibroblast to ECM.
4. Syndecan - binds to collagen & other
glycoproteins.
5. CD44 – binds to glycoproteins.
54
55. Glycoprotiens:
Three distinctly related glycoprotiens of the
extra cellular matrix have been localized in
the decalcified sections of human
periodontal ligament, namely
Fibronectin
Tenascin
Laminin
Other glycoproteins like Entactin,
Vitronectin, Thrombospondin may also be
present in the glycoprotiens of PDL with a
smaller role in cell attachment and
organization of basement membrane.
55
56. I. Physical function
II. Formative & Remodeling
III. Nutritional
IV. Homeostatic
V. Sensory function.
56
57. I.PHYSICAL FUNCTION :
Provision of a soft tissue ‘casing’ to protect the
vessels and nerves from injury by mechanical
forces.
Transmission of occlusal forces to the bone.
Attachment of the teeth to the bone.
Maintainence of the gingival tissues in their
proper relationship to the teeth.
Resistance to the impact of occlusal forces
(Shock absorption).
57
58. II.FORMATIVE AND REMODELING FUNCTION :
Cells of the PDL participate in the formation and
resorption of cementum and bone, which occur
in - physiologic tooth movement,
- accommodation of the periodontium to occlusal
forces
- in the repair of injures.
Remodeling : The 3-D organization of the fiber
meshwork is adapted to accommodate for
positional changes of the tooth in its socket or
changes in functional state (such as
hypofunction).
It relates to adaptability of PDL tissues.
Both these processes can occur simultaneously
and may therefore be indistinguishable.
58
59. The PDL is constantly undergoing remodeling.
Old cells & fibers are broken down &
replaced by new ones, & mitotic activity can
be observed in the fibroblasts & endothelial
cells.
59
60. III. NUTRITIONAL:
PDL supplies nutrients to the cementum , bone, and
gingiva by way of blood vessels and provides lymphatic
drainage.
The PDL contains blood vessels, which provide anabolites
and other substance to the cementum, bone and gingiva. &
removes catabolites.
IV. HOMEOSTATIC:
Adaptability to rapidly changing applied forces and its
capacity to maintain its width at constant diameter
throughout life.
Its is evident that the cells of PDL have the ability to
resorb and synthesize the extracellular substance of the
connective tissue of the ligament , alveolar bone and
cementum
60
61. SENSORY FUNCTION:
The PDL is abundantly supplied with sensory nerve fibers
capable of the repair of transmitting tactile, pressure and
pain sensations by the trigeminal pathway.
The PDL provides a most efficient proprioceptive
mechanism.
4 types of neural terminations are seen
1. Free nerve endings –pain(at regular intervals along
the length of the root.
2. Ruffini like mechanoreceptors (apical area)
3. Meissner’s corpuscles - mechanoreceptors (middle
3rd)
4. Spindle like pressure and vibration endings (apex)
61
62. Increase in the collagen fibrosis & decrease in
cellularity .
Areas of hyalinization are present.
Sporadic mineralization of the fibers also occurs.
Decrease in the no. of periodontal fibers
Decrease in the cellularity & the formation of
multinucleated fibroblasts.
Decrease in collagen synthesis.
The surfaces of the periodontal alveolar bone
are jagged & uneven an irregular insertion of
fibers is seen.
Replacement of some of the PDL space by
interstitial areas & fat cells.
Structural organization of the ligament
degenerates with age.
62
63. If gingivitis is not cured and supporting structure
become involved, the disease is termed as
periodontitis.
There are few coccal cells and more motile rods
and spirochetes in the diseased site than in the
healthy site.
The bacteria consists of gram-positive
facultative rods and cocci in healthy site while in
diseased site, gram-negative rods and anaerobes
are more in number.
Resorption and formation of both bone and
periodontal ligament play an important role in
orthodontic tooth movement. If tooth movement
takes place, the compression of PDL is
compensated by bone resorption whereas on
tension side, apposition takes place.
63
64. Inflammation of the pulp reached to the
apical periodontal ligament and replaces its
fiber bundles with granulation tissue called
as granuloma, which then progresses into
apical cyst.
Chronic periodontal disease can lead to
infusion of microorganisms into the blood
stream.
The pressure receptors in ligament have a
protective role. Apical blood vessels are
protected from excessive compression by
sensory apparatus of the teeth.
64
65. NEOPLASTIC INVOLVEMENT OF PDL:
Mostly reactive rather than neoplastic.
Oxytalan fibers are found in peripheral
odontogenic fibromas & Adenomatoid
odontogenic tumors
Epithelial rests of malassez --- neoplastic
change
Infiltration of PDL by primary or secondary
malignant tumors --- widening of PDL space--
- mobility –malignant loosening of teeth.
65
66. PERIODONTAL CYSTS :
Inflammatory ---- Radicular cyst
Developmental ---- Lateral periodontal cyst
PDL space Radiographic appearance :
Thin radiolucent line interposed between the
root & lamina dura.
Occlusal Trauma → widened PDL space or
funneling of coronal aspect of PDL space.
It can also widened in case of vertical
fractures & progressive systemic sclerosis
(Scleroderma).
66
67. The periodontal ligament is a fibrous connective
tissue forming important part of the
Periodontium.
The PDL is a physically small, but functionally
important tissue in tooth support, proprioception
and regulation of alveolar bone volume.
The PDL is an absolute requirement for rapid
remodeling of alveolar bone when forces are
applied to teeth.
Cell of the periodontal ligament are Pluri-potent
and helps in the regeneration of all the
components of Periodontium lost in the
periodontal disease process.
67
68. Carranza’s Clinical Periodontology, 10th
Edition
Clinical Periodontology and Implantology by
Jan Lindhe, 5th edition
Oral Histology and Embryology by Orban,
13th edition
Tencate oral histology, 5th edition
68