This slide is about mechanism of mastication. it include muscles of mastication. disorders .of masticatory muscles also included. mastication in different condition is also presented
THEORIES OF ERUPTION
ERUPTION SEQUENCE
PHYSIOLOGY OF TOOTH ERUPTION
CELLULAR BASIS
MOLECULAR BASIS
PRODUCTION OF OSTEOCLAST
ANOMOLIES OF TOOTH ERUPTION
The document discusses the complex process of tooth development from initiation to eruption. It begins with the formation of the primary epithelial bands and dental lamina between 6-7 weeks in utero, which give rise to the tooth buds. The buds progress through stages of proliferation, histodifferentiation, and morphodifferentiation to form the crown and root structures. Hertwig's epithelial root sheath is responsible for root formation and shape before teeth erupt into the oral cavity.
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 summarizes the development of teeth from the dental lamina. It discusses how the primary epithelial band forms and divides into the dental lamina and vestibular lamina. Tooth buds then develop from the dental lamina, forming the enamel organ, dental papilla, and dental follicle. Teeth progress through developmental stages including the bud stage, cap stage, bell stage, and root formation. The dental lamina gives rise to both primary and permanent teeth before degenerating.
Theories of Mineralization
There are three main theories of mineralization:
1) Robinson's phosphate theory which involves alkaline phosphatase increasing local phosphate levels for hydroxyapatite formation.
2) Nucleation theory where nucleating substances like proteoglycans and collagen fibrils initiate crystal formation.
3) Matrix vesicle theory which is most accepted - matrix vesicles accumulate calcium and phosphate ions to form initial mineral complexes within their membranes before releasing crystals into the extracellular matrix.
A Complete presentation explaining the complete morphology of Maxillary first molar, for the benefit of people like me who tried and failed to find everything in one package
1) Mastication involves the chewing and grinding of food using the teeth and muscles of mastication. As food is broken down, it is mixed with saliva and prepared for swallowing.
2) The muscles of mastication work in a coordinated manner through opening and closing strokes to crush and grind food between the teeth. Sensory feedback and reflexes help coordinate this chewing cycle.
3) After sufficient mastication, the food is swallowed through a coordinated process of deglutition involving the oral, pharyngeal, and esophageal phases to transport the food bolus to the stomach for further digestion.
This document provides information on the anatomy of permanent mandibular molars. It describes the identifying features, anatomical aspects, and differences between upper and lower molars for the mandibular first, second, and third molars. Key details include the number and shape of cusps, developmental grooves, roots, and contact areas for each tooth. Differences between upper and lower molars are also summarized such as the number of roots, presence of an oblique ridge, and shape of cusps on the mesial aspect.
THEORIES OF ERUPTION
ERUPTION SEQUENCE
PHYSIOLOGY OF TOOTH ERUPTION
CELLULAR BASIS
MOLECULAR BASIS
PRODUCTION OF OSTEOCLAST
ANOMOLIES OF TOOTH ERUPTION
The document discusses the complex process of tooth development from initiation to eruption. It begins with the formation of the primary epithelial bands and dental lamina between 6-7 weeks in utero, which give rise to the tooth buds. The buds progress through stages of proliferation, histodifferentiation, and morphodifferentiation to form the crown and root structures. Hertwig's epithelial root sheath is responsible for root formation and shape before teeth erupt into the oral cavity.
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 summarizes the development of teeth from the dental lamina. It discusses how the primary epithelial band forms and divides into the dental lamina and vestibular lamina. Tooth buds then develop from the dental lamina, forming the enamel organ, dental papilla, and dental follicle. Teeth progress through developmental stages including the bud stage, cap stage, bell stage, and root formation. The dental lamina gives rise to both primary and permanent teeth before degenerating.
Theories of Mineralization
There are three main theories of mineralization:
1) Robinson's phosphate theory which involves alkaline phosphatase increasing local phosphate levels for hydroxyapatite formation.
2) Nucleation theory where nucleating substances like proteoglycans and collagen fibrils initiate crystal formation.
3) Matrix vesicle theory which is most accepted - matrix vesicles accumulate calcium and phosphate ions to form initial mineral complexes within their membranes before releasing crystals into the extracellular matrix.
A Complete presentation explaining the complete morphology of Maxillary first molar, for the benefit of people like me who tried and failed to find everything in one package
1) Mastication involves the chewing and grinding of food using the teeth and muscles of mastication. As food is broken down, it is mixed with saliva and prepared for swallowing.
2) The muscles of mastication work in a coordinated manner through opening and closing strokes to crush and grind food between the teeth. Sensory feedback and reflexes help coordinate this chewing cycle.
3) After sufficient mastication, the food is swallowed through a coordinated process of deglutition involving the oral, pharyngeal, and esophageal phases to transport the food bolus to the stomach for further digestion.
This document provides information on the anatomy of permanent mandibular molars. It describes the identifying features, anatomical aspects, and differences between upper and lower molars for the mandibular first, second, and third molars. Key details include the number and shape of cusps, developmental grooves, roots, and contact areas for each tooth. Differences between upper and lower molars are also summarized such as the number of roots, presence of an oblique ridge, and shape of cusps on the mesial aspect.
Mastication is the process of chewing food using the teeth and jaws. It breaks food into smaller pieces to increase surface area for digestion and mixes food with saliva. Mastication occurs via convergent movements of the maxilla and mandible, initially crushing food followed by shearing movements. Sensory receptors provide feedback to control rhythmic jaw movements generated by central pattern generators in the brainstem. Oral reflexes like the jaw jerk response help regulate mastication.
https://userupload.net/3ppacneii1wj
Toxicologic Pathology (Second Edition), 2010
INTRODUCTION
The oral mucosa is, in many ways, similar to the skin in its architecture, function, and reaction patterns. This section only emphasizes those characteristics of the oral mucosa that influence or result in a distinct group of pathologic entities.
Because of its location at the entrance of the digestive and respiratory tracts and its proximity to the teeth, the oral mucosa is subjected to numerous natural and man-made xenobiotics. The peculiar architecture and absorption characteristics of the oral mucosa, especially in areas of extreme thinness, coupled with the rich microorganism flora of the mouth, makes the oral mucosa a peculiar site deserving separate discussion.
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.
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.
It is a presentation in detail about the strongest structure of the oral cavity "ENAMEL". It is a simple topic but people find it difficult to learn about it. I hope my presentation is a simple method to learn about it. I would like to thank my professors for assign me this project and i learn't a lot from it and still learning my basics daily.
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.
Occlusion is defined as the contact relationship of the teeth in function or parafunction.
Malocclusion is defined as the misalignment of teeth and jaws, or more simply, a "bad bite". Malocclusion can cause a number of health and dental problems.
The document summarizes the development and growth process of teeth. It begins with the formation of the primitive oral cavity and buccopharyngeal membrane. It then discusses the development of the primary epithelial band and dental lamina. The key stages of tooth development are described - the bud stage, cap stage, bell stage, and root formation stage. The roles of the enamel organ, dental papilla, dental sac, and Hertwig's epithelial root sheath in determining tooth shape and root development are also summarized.
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 the anatomy, development, and prosthodontic considerations of the hard and soft palate. It begins with an introduction to the palate and its two parts: the anterior hard palate and posterior soft palate. It then covers the embryological development of the palate and anatomical structures of both parts such as bones, muscles, nerves and vessels. Developmental anomalies including clefts are described along with various classification systems. Finally, it discusses prosthodontic factors relevant to constructing dentures, such as determining border extent and seals based on palatal anatomy and physiology.
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.
This document discusses various theories of tooth eruption and the phases of tooth eruption. It summarizes six main theories of tooth eruption: root elongation theory, bone remodeling theory, periodontal ligament contraction theory, hydrostatic pressure theory, pulp constriction theory, and dental follicle theory. It states that the periodontal ligament contraction theory, whereby fibroblasts in the periodontal ligament contract to apply an axial force, is the most widely accepted. It also outlines the three phases of tooth eruption: pre-eruptive, eruptive, and post-eruptive phases.
The document discusses the relationship between tooth form and function. It explains how characteristics like root size and shape, crown size, contact areas, and embrasures are proportional to each other and related to jaw movements. Tooth form directly influences jaw morphology and movements. For example, humans have more complex tooth anatomy and jaw movements compared to animals with simpler conical teeth. The positions of contact areas, contours, embrasures, and occlusal curves are adapted for functions like mastication, protection of tissues, and self-cleansing of teeth.
Dentinogenesis is the formation of dentin, which begins before enamel formation. Dentin is formed by odontoblast cells in two phases: first the formation of an organic collagen matrix, followed by deposition of hydroxyapatite crystals. As dentinogenesis begins, odontoblasts elongate and secrete an unmineralized collagen matrix called predentin. Over time, predentin adjacent to the pulp mineralizes and forms dentin while new predentin is deposited, resulting in incremental dentin growth of approximately 4 micrometers per day. Dentinogenesis continues throughout life but slows after eruption.
This document discusses important anatomical landmarks for complete dentures in the maxilla and mandible. It describes 14 maxillary landmarks including the labial and buccal frenums, vestibules, alveolar ridge, tuberosity, hamular notch, hard palate features, and rugae. It also describes 9 mandibular landmarks like the labial and lingual frenums and vestibules, buccal shelf area, retromolar pad, and pear shaped pad. Understanding these landmarks is essential for proper denture fit and function as well as preservation of underlying tissues.
Growth & development of maxilla and mandibleRajesh Bariker
The document discusses the pre-natal and post-natal growth and development of the maxilla and mandible. It describes how the maxilla forms from embryonic development and ossification centers. It grows through displacement, remodeling at sutures, and increases in height, width and length. The mandible develops from Meckel's cartilage and also grows through remodeling at sites of growth. The palate develops from primary and secondary palatal shelves fusing in the midline. Post-natally, the maxilla grows through apposition at sutures and displacement downward and forward from cranial base growth. The mandible grows through remodeling at sites like the ramus and condyle.
The document discusses the muscles of mastication. It describes the four primary muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid. It details the origin, insertion, nerve supply, blood supply, actions and functions of each muscle. The document also briefly discusses secondary muscles like the suprahyoid muscles. Clinical considerations related to the muscles of mastication like tetanus, bruxism, and myofascial pain dysfunction syndrome are mentioned at the end.
The document discusses the muscles involved in mastication. It describes the primary muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid - which attach to the mandible and aid in elevating, depressing, and moving the jaw laterally. The secondary muscles of mastication - the suprahyoid muscles like digastric, mylohyoid, and geniohyoid - provide supporting functions. Clinical considerations related to these muscles like tetanus, bruxism, and myofascial pain dysfunction syndrome are also outlined.
Mastication is the process of chewing food using the teeth and jaws. It breaks food into smaller pieces to increase surface area for digestion and mixes food with saliva. Mastication occurs via convergent movements of the maxilla and mandible, initially crushing food followed by shearing movements. Sensory receptors provide feedback to control rhythmic jaw movements generated by central pattern generators in the brainstem. Oral reflexes like the jaw jerk response help regulate mastication.
https://userupload.net/3ppacneii1wj
Toxicologic Pathology (Second Edition), 2010
INTRODUCTION
The oral mucosa is, in many ways, similar to the skin in its architecture, function, and reaction patterns. This section only emphasizes those characteristics of the oral mucosa that influence or result in a distinct group of pathologic entities.
Because of its location at the entrance of the digestive and respiratory tracts and its proximity to the teeth, the oral mucosa is subjected to numerous natural and man-made xenobiotics. The peculiar architecture and absorption characteristics of the oral mucosa, especially in areas of extreme thinness, coupled with the rich microorganism flora of the mouth, makes the oral mucosa a peculiar site deserving separate discussion.
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.
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.
It is a presentation in detail about the strongest structure of the oral cavity "ENAMEL". It is a simple topic but people find it difficult to learn about it. I hope my presentation is a simple method to learn about it. I would like to thank my professors for assign me this project and i learn't a lot from it and still learning my basics daily.
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.
Occlusion is defined as the contact relationship of the teeth in function or parafunction.
Malocclusion is defined as the misalignment of teeth and jaws, or more simply, a "bad bite". Malocclusion can cause a number of health and dental problems.
The document summarizes the development and growth process of teeth. It begins with the formation of the primitive oral cavity and buccopharyngeal membrane. It then discusses the development of the primary epithelial band and dental lamina. The key stages of tooth development are described - the bud stage, cap stage, bell stage, and root formation stage. The roles of the enamel organ, dental papilla, dental sac, and Hertwig's epithelial root sheath in determining tooth shape and root development are also summarized.
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 the anatomy, development, and prosthodontic considerations of the hard and soft palate. It begins with an introduction to the palate and its two parts: the anterior hard palate and posterior soft palate. It then covers the embryological development of the palate and anatomical structures of both parts such as bones, muscles, nerves and vessels. Developmental anomalies including clefts are described along with various classification systems. Finally, it discusses prosthodontic factors relevant to constructing dentures, such as determining border extent and seals based on palatal anatomy and physiology.
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.
This document discusses various theories of tooth eruption and the phases of tooth eruption. It summarizes six main theories of tooth eruption: root elongation theory, bone remodeling theory, periodontal ligament contraction theory, hydrostatic pressure theory, pulp constriction theory, and dental follicle theory. It states that the periodontal ligament contraction theory, whereby fibroblasts in the periodontal ligament contract to apply an axial force, is the most widely accepted. It also outlines the three phases of tooth eruption: pre-eruptive, eruptive, and post-eruptive phases.
The document discusses the relationship between tooth form and function. It explains how characteristics like root size and shape, crown size, contact areas, and embrasures are proportional to each other and related to jaw movements. Tooth form directly influences jaw morphology and movements. For example, humans have more complex tooth anatomy and jaw movements compared to animals with simpler conical teeth. The positions of contact areas, contours, embrasures, and occlusal curves are adapted for functions like mastication, protection of tissues, and self-cleansing of teeth.
Dentinogenesis is the formation of dentin, which begins before enamel formation. Dentin is formed by odontoblast cells in two phases: first the formation of an organic collagen matrix, followed by deposition of hydroxyapatite crystals. As dentinogenesis begins, odontoblasts elongate and secrete an unmineralized collagen matrix called predentin. Over time, predentin adjacent to the pulp mineralizes and forms dentin while new predentin is deposited, resulting in incremental dentin growth of approximately 4 micrometers per day. Dentinogenesis continues throughout life but slows after eruption.
This document discusses important anatomical landmarks for complete dentures in the maxilla and mandible. It describes 14 maxillary landmarks including the labial and buccal frenums, vestibules, alveolar ridge, tuberosity, hamular notch, hard palate features, and rugae. It also describes 9 mandibular landmarks like the labial and lingual frenums and vestibules, buccal shelf area, retromolar pad, and pear shaped pad. Understanding these landmarks is essential for proper denture fit and function as well as preservation of underlying tissues.
Growth & development of maxilla and mandibleRajesh Bariker
The document discusses the pre-natal and post-natal growth and development of the maxilla and mandible. It describes how the maxilla forms from embryonic development and ossification centers. It grows through displacement, remodeling at sutures, and increases in height, width and length. The mandible develops from Meckel's cartilage and also grows through remodeling at sites of growth. The palate develops from primary and secondary palatal shelves fusing in the midline. Post-natally, the maxilla grows through apposition at sutures and displacement downward and forward from cranial base growth. The mandible grows through remodeling at sites like the ramus and condyle.
The document discusses the muscles of mastication. It describes the four primary muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid. It details the origin, insertion, nerve supply, blood supply, actions and functions of each muscle. The document also briefly discusses secondary muscles like the suprahyoid muscles. Clinical considerations related to the muscles of mastication like tetanus, bruxism, and myofascial pain dysfunction syndrome are mentioned at the end.
The document discusses the muscles involved in mastication. It describes the primary muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid - which attach to the mandible and aid in elevating, depressing, and moving the jaw laterally. The secondary muscles of mastication - the suprahyoid muscles like digastric, mylohyoid, and geniohyoid - provide supporting functions. Clinical considerations related to these muscles like tetanus, bruxism, and myofascial pain dysfunction syndrome are also outlined.
Muscles of mastication are the group of muscles that help in movement of the mandible as during chewing and speech. We need to study these muscles as they control the opening & closing the mouth & their role in the equilibrium created within the mouth. They also play a role in the configuration of face.
The document provides information about the muscles of mastication. It defines masticatory muscles as the muscles that elevate the mandible to close the mouth. There are four primary muscles - temporalis, masseter, medial pterygoid, and lateral pterygoid. The document describes the origin, insertion, innervation, blood supply, functions, and clinical significance of each of these muscles. It also discusses accessory muscles like mylohyoid, geniohyoid, and anterior belly of digastric. The document emphasizes the importance of understanding masticatory muscles for dental treatments.
The document discusses the muscles of mastication. There are 4 primary muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid. These muscles develop from the first brachial arch and are innervated by the mandibular nerve. They work together to power the chewing cycle and move the mandible during opening, closing, and side-to-side motions. Secondary muscles like the digastric, mylohyoid, and geniohyoid can assist during difficult chewing. Conditions like tetanus and bruxism are also reviewed.
This document discusses the muscles of mastication. It begins by defining mastication and describing the development of muscles from embryonic tissues. The primary muscles of mastication - masseter, temporalis, lateral pterygoid, and medial pterygoid - are then described in detail, including their origins, insertions, nerve/blood supply, and actions. Secondary muscles like the digastric, mylohyoid, and geniohyoid that assist in mastication are also outlined. The document concludes that the masticatory system requires precise muscle movement to effectively move the teeth during function.
A brief ppt on stomatognathic system and its working.Function can influence the overall pattern and the relationship of parts, the very foundations of stomatognathic system.
We should do more than just analyze teeth in occlusion.
It is equally important to appreciate respiration, mastication, deglutition, speech and even maintenance of head in constant postural position.
The document discusses the muscles of mastication - the muscles involved in chewing. It describes the anatomy, development, functions and clinical significance of the main muscles - the masseter, temporalis, lateral and medial pterygoid muscles. Conditions involving the muscles like myofascial pain dysfunction syndrome, trismus and benign masseteric hypertrophy are also covered. The muscles of mastication are important for prosthodontists to consider during treatments like impression making and recording jaw relations.
The document discusses the muscles of mastication - masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. It covers the origin, insertion, innervation, action, and clinical considerations of each muscle. It also discusses the role of these muscles in supporting complete denture prostheses, including how the contours of the denture should relate to the underlying muscles. The document provides anatomical and clinical context regarding the functions of the masticatory muscles.
This document discusses the muscles of mastication. It begins by introducing the muscles and their anatomy. The primary muscles of mastication are the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. It describes the origin, insertion, nerve supply, blood supply, and actions of each muscle. Additionally, it covers related topics like the embryology of the muscles, clinical considerations like trismus and bruxism, and the significance of the muscles in orthodontics.
The document discusses the muscles of mastication. It describes the primary muscles - temporalis, masseter, medial pterygoid, and lateral pterygoid muscles. The secondary muscles include the digastric, mylohyoid, and geniohyoid muscles. The development of the muscles from pharyngeal arches is explained. Clinical features like myalgia, myositis, trismus, and hypertrophy affecting the muscles are also covered. Management options for various conditions are summarized.
The document discusses the stomatognathic system, which includes the structures and functions involved in chewing, swallowing, breathing, and speaking. It describes the key structures - jaws, teeth, tongue, and muscles. The muscles involved include the temporalis, masseter, medial and lateral pterygoid muscles. It discusses the functions of mastication (chewing), deglutition (swallowing), respiration, and speech. Mastication involves preparing the food, crushing it between teeth, and grinding it using temporal and masseter muscles. Swallowing then moves the crushed food to the pharynx.
The document discusses the muscles of mastication. It describes the temporalis, masseter, lateral pterygoid, medial pterygoid, digastric, geniohyoid, and mylohyoid muscles. It details the origin, insertion, nerve supply and action of each muscle. The document also discusses clinical evaluation and disorders of the masticatory muscles, including myofascial pain, myositis, and myospasm.
This document provides an overview of the muscles of mastication. It begins by defining muscle and mastication. It then discusses the development, classification, properties and functions of the primary muscles of mastication - the masseter, temporalis, lateral pterygoid, and medial pterygoid muscles. The document also covers the accessory muscles of mastication and their functions. Finally, it discusses some clinical considerations regarding these muscles, including bruxism, tetanus, and myofascial pain disorders.
As we know that the muscles play an important role in stability and support of a prosthesis,hence we should be well learned about their peripheries and actions.
The document summarizes the muscles of mastication. It defines muscles and mastication, and describes the development, classification, and functions of the primary muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid. It provides details on the origin, insertion, nerve/blood supply, actions, and clinical importance of each muscle. It also briefly discusses the accessory muscles and chewing cycle.
The document summarizes the muscles of mastication, including their origin, insertion, function, nerve and blood supply, and clinical significance. It discusses the four primary muscles - temporalis, masseter, lateral pterygoid, and medial pterygoid - as well as some accessory muscles like the digastric. The temporalis muscle elevates the mandible, the masseter muscle elevates and moves the mandible laterally, the lateral pterygoid muscle depresses and protrudes the mandible, and the medial pterygoid muscle elevates and closes the jaw. Understanding the muscles of mastication is important for dentistry, prosthodontics and evaluating facial pain disorders
The temporalis, masseter, medial pterygoid, and lateral pterygoid muscles are the primary muscles of mastication. They develop from the mesoderm of the first pharyngeal arch and receive innervation from the mandibular branch of the trigeminal nerve. The temporalis muscle elevates the mandible, while the masseter muscle elevates and moves the mandible sideways. The lateral and medial pterygoid muscles protrude the mandible. Accessory muscles like the digastric, mylohyoid, and geniohyoid aid in mandibular depression and elevation of the hyoid bone. Masticatory muscle disorders involve pain and dysfunction and include conditions
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share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
• Equipping health professionals to address questions, concerns and health misinformation
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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.
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
2. CONTENTS
Introduction
Definition
Muscles of mastication
Function of mastication
Chewing stroke
Muscular activity during mastication
Mandibular movements during
mastication
Tooth contact during mastication
Forces of mastication
Role of soft tissue in mastication
Chewing reflexes
Control of mastication
Mastication in denture bearer
Mayofascial pain dysfunction
Prosthetic management of masticatory
muscle disorder
Conclusion
References
2
3. INTRODUCTION
Mastication is one of the main functions of the stomatognathic system.
Mastication is also an important factor and a stimulus for normal craniofacial
growth.
The masticatory system is a functional unit composed of the teeth; their
supporting structures, the jaws; the temporomandibular joints; the muscles
involved directly or indirectly in mastication (including the muscles of the lips
and tongue); and the vascular and nervous systems supplying these tissues.
Mastication is the action of breaking down of food, preparatory to deglutition.
This breaking down action is highly organized complex of neuromuscular and
digestive activities.
3
4. DEFINATIONS
Mastication: the process of chewing food for swallowing and digestion. (GPT-9)
Masticatory system: the organs and structures primarily functioning in mastication; these
include the teeth with their supporting structures, craniomandibular articulations, mandible,
positioning and accessory musculature, tongue,lips, cheeks, oral mucosa, and the associated
neurologic complex. (GPT-9)
Masticatory efficiency: the effort required to achieve a standard degree of comminution of
food. (GPT-9)
Masticatory movements: mandibular movements used for chewing food. (GPT-9)
4
5. • MUSCLES OF MASTICATION
Muscles of mastication moves the mandible during mastication and speech.
They develop from the mesoderm of the first branchial arch at the starting of
7th week and are supplied by the mandibular nerve which is the nerve of that
arch.
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.144
6
6. • CLASSIFICATION OF
MUSCLES OF
MASTICATION
6
MUSCLES OF
MASTICATION
PRIMARY
Masseter
Temporalis
Lateral
pterygoid
Medial
Pterygoid
ACCESSARY
Digastric
Stylohyoid
Mylohyoid
Geniohyoid
8. 8
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.146
2. Wheeler’s dental anatomy, physiology and occlusion;9th edition;2012.p. 266
9. 1. Masseter
9
Origin Action
Nerve supply
Insertion
Active during forceful
jaw closing and may
assist in protrusion of
the mandible.
Masseteric nerve, a
branch of anterior
division of
mandibular nerve
• Superficial layer (largest):
from anterior 2/3rd of
zygomatic acrh and
adjoining zygomatic
process
• Middle layer: from
anterior 2/3rd of deep
surface and posterior
1/3rd of border of
zygomatic arch
• Deep layer: from deep
surface of zygomatic
• Superficial layer: into
lower part of lateral
surface of ramus
• Middle layer: into
middle part of ramus
• Deep
layer(zygomaticomand
ibular muscle): into
upper part of ramus
and coronoid process
of the mandible
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.145
2. Wheeler’s dental anatomy, physiology and occlusion;9th edition;2012.p. 265
10. 2. Temporalis
10
Origin Action
Nerve supply
Insertion
• Principal positioner
of mandible during
elevation.
• The posterior part is
active in retruding
the mandible.
• The anterior part is
synergistic to
masseter in
protrusion and helps
in clenching.
Two deep temporal
nerve from anterior
division of
mandibular nerve
• Temporal fossa
excluding zygomatic
bone
• Temporal fascia
• Margins and deep
surface of coronoid
process
• Anterior border of
ramus of mandible
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.145
2. Wheeler’s dental anatomy, physiology and occlusion;9th edition;2012.p. 268
11. 11
Position of masseter and temporalis muscle
2. Wheeler’s dental anatomy, physiology and occlusion;9th edition;2012.p. 268
12. 3. Lateral Pterygoid
12
Origin Action
Nerve supply
Insertion
• Depress mandible to
open mouth with
suprahyoid muscle.
• Protrude the
mandible.
• Left lateral pterygoid
and right medial
pterygoid turn the
chin to left side as
part of grinding
movements.
Nerve from anterior
division of
mandibular nerve
• Upper head (small): from
infratemporal surface
and crest of greater wing
of sphenoid bone.
• Lower head (large): from
Lateral surface of Lateral
Pterygoid plate.
• Pterygoid fovea on
the anterior surface of
neck of the mandible.
• Anterior margin of
articulator disc and
capsule of
temporomandibular
joint. (insertion is
posterolateral and
slightly higher level
than origin.)
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.145
13. 4. Medial Pterygoid
13
Origin Action
Nerve supply
Insertion
• Elevates the
mandible
• Helps in protrusion
of mandible.
• Lateral positioning of
mandible.
Nerve to medial
pterygoid, branch
from main trunk of
mandibular nerve
• Superficial head (small):
from tuberosity of
maxilla and adjoining
bone.
• Deep head (large): from
medial surface of lateral
pterygoid plate and
adjoining process of
palatine bone.
• Roughened areas
on medial surface
of angle and
adjoining surface of
mandible ramus,
below and behind
the mandibular
foramen and
mylohyoid groove.
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.145
2. Wheeler’s dental anatomy, physiology and occlusion;9th edition;2012.p. 268
14. 14
Position of lateral and medial pterygoid muscle
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.146
16. 5. Digastric
16
Origin Action
Nerve supply
Insertion
• Depress the
mandible
• Elevates the hyoid
bone
• Anterior belly:
nerve to
mylohyoid branch
of mandibular
nerve
• Posterior belly:
facial nerve
• Anterior belly: from
digastric fossa of
mandible
• Posterior belly: From
mastoid notch of
temporal bone
• Both heads meet at
the intermediate
tendon which
perforates
suprahyoid muscle
and is held by
fibrous pulley to
the hyoid bone.
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.158
17. 6. Stylohyoid
17
Origin Action
Nerve supply
Insertion
• Pulls hyoid bone
upward and
backword
• With other hyoid
muscle fixes the
hyoid muscle.
• Facial nerve
• Posterior surface of
styloid process
• Junction of body
and greater cornua
of hyoid bone
BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.158
19. 7. Mylohyoid
19
Origin Action
Nerve supply
Insertion
• Elevates the floor of
mouth
• Helps in depression
of mandible and
elevation of hyoid
bone
• Nerve to
mylohyoid
• Mylohyoid line of
mandible.
• Posteriors fibers:
body of hyoid bone
• Middle and anterior
fibers: median
raphe, between
mandible and
hyoid bone
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.158
20. 8. Geniohyoid
20
Origin Action
Nerve supply
Insertion
• Helps in depression
of mandible and
elevation of hyoid
bone
• C1 through
hypoglossal nerve
• Inferior mental spine.
• Anterior surface of
body of hyoid bone
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS Publisher 2004. p.158
21. 1. Masticatory Myofascial pain
2. Masticatory myalgia
3. Masticatory myospasm
4. Myofibrotic contracture
5. Myositis
6. Bruxism
7. Temporomandibular joint dysfunction
8. Tumor
21
• Pathology related to masticatory
muscle
3. Basit H, Tariq MA, Siccardi MA. Anatomy, Head and Neck, Mastication Muscles. StatPearls [Internet], 2020.
22. Break up food as the first stage of digestion. The surface area of food is
increased, allowing for increased nutrient absorption.
stimulate the hippocampus in the brain. The act of chewing transmits nerve
impulses to the hippocampus in the central nervous system and also increases
blood flow to the brain. Stimulation of the hippocampus is critical for learning
and spatial memory.
22
• Functions of mastication
4. Helmenstine, Anne Marie, Ph.D. "Mastication: Definition and Functions." ThoughtCo, Aug. 29, 2020.
23. • Chewing stroke
Mastication is made up of rhythmic and well-controlled separation and closure
of the maxillary and mandibular teeth.
This activity is under the control of the CPG (central pattern generator) located
in the brainstem.
tear-shaped movement pattern.
Each chewing cycle lasts approximately 0.8-1.0 s.
23
Chewing
stroke
Opening
phase
Closing
phase
Crushing
phase
Grinding
phase
5. JEFFREY P
. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p39
24. • In frontal plane
24
5. JEFFREY P
. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p40
25. 25
Mandible drops downward from the intercuspal position to a
point where the incisal edges of the teeth are about 16 to 18 mm
apart.
It then moves laterally 5 to 6 mm from the midline as the
closing movements begins.
The first phase of closure traps the food between the teeth and
is called the crushing phase. As the teeth approach each other,
the lateral displacement is lessened so that when the teeth are
only 3 mm apart the jaw occupies a position only 3 to 4 mm
lateral to the starting position of the chewing stroke.
When the mandible is traced in the frontal plane during a single chewing stroke, the
following sequence occurs:
Opening phase:
Closing phase:
Crushing phase:
26. 26
At this point the teeth are so positioned that the buccal cusps
of the mandibular teeth are almost directly under the buccal
cusps of the maxillary teeth on the side to which the mandible
has been shifted.
As the mandible continues to close, the bolus of food is
trapped between the teeth.
During the grinding phase the mandible is guided by the
occlusal surfaces of the teeth back to the intercuspal position,
which causes the cuspal inclines of the teeth to pass across each
other, permitting shearing and grinding of the bolus of food.
Grinding phase:
5. JEFFREY P. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6
28. • IN THE SAGITTAL
PLANE OF THE
WORKING SIDE.
28
• During opening, the incisor moves slightly anterior to
the intercuspal position (ICP) and then returns from a
slightly posterior position.
• The molar begins with an anterior movement during
the opening phase and a more posterior movement
during the closing stroke.
• The working side condyle also moves posteriorly during
the closing stroke until final closure, when it shifts
anteriorly to the intercuspal position.
6. Lundeen HC, Gibbs CH: Advances in occlusion, Boston, 1982, John Wright PSG
29. 29
6. Lundeen HC, Gibbs CH: Advances in occlusion, Boston, 1982, John Wright PSG
30. • IN THE SAGITTAL PLANE
OF THE NON WORKING
SIDE.
30
• The first molar initially drops from the intercuspal
position (IP) almost vertically with little to no anterior
or posterior movement.
• The final stage of the closing stroke is also almost
completely vertical.
• The condyle on the nonworking side moves anteriorly
during opening and follows almost the same pathway
on its return.
• The nonworking side condyle is never situated
posterior to the intercuspal position.
6. Lundeen HC, Gibbs CH: Advances in occlusion, Boston, 1982, John Wright PSG
31. 31
6. Lundeen HC, Gibbs CH: Advances in occlusion, Boston, 1982, John Wright PSG
32. • When food is initially introduced into the
mouth, the amount of lateral movement is
great and then becomes less as the food is
broken down.
• The amount of lateral movement also varies
according to the consistency of the food.
• The harder the food, the more lateral the
closure stroke becomes.
• The hardness of the food also has an effect
on the number of chewing strokes necessary
before a swallow is initiated: the harder the
food, the more chewing strokes needed.
32
5. JEFFREY P. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p42
33. • Muscular activity during mastication
6.
6. Lavelle, Christopher L.B. (1988). Applied Oral Physiology || Mastication. , (), 12–24.
33
During both the opening and beginning of the closing phases, the masticatory muscles undergo
isotonic contraction or relaxation. In the latter part of the closing and occlusal phases, however,
tension builds up in the elevator muscles.
Elevator muscular contraction is strictly isometric only when the teeth are in contact or when there is a
hard unyielding object in between them. During chewing, the change from isotonic to isometric
contraction is usually not abrupt but rather a gradual change during the latter part of the closing
phase.
During the closing phase of mastication, the temporalis muscle on the working side is the first to
become active, followed by both masseters and the temporalis of the balancing (non-working) side.
34. 34
The masseter and medial pterygoids are the first to become active during an incisive
movement. The lateral pterygoid muscle is active during both mandibular protrusion and
opening, although it is not strictly a mandibular depressor.
The suprahyoid muscles (digastric, geniohyoid and mylohyoid muscles) become active during
jaw opening, although hyoid stabilization through infrahyoid and stylohyoid muscle contraction
is a necessary prerequisite. During the initial phase of isotonic closing from an open position,
the depressor muscles are first activated. The depressor muscles then gradually relax to allow
the mouth to be closed by the passive tension in the elevator muscles and ligaments.
The muscles responsible for mandibular opening may be placed in the following order of
activity:
(1) Mylohyoid. (2) Digastric. (3) Lateral pterygoid.
This serves to stabilize the mandibular condyle or move the condyle anteriorly or posteriorly during
opening, closing and protrusive mandibular movements.
The primary muscles responsible for mandibular closing include:
(1) The temporalis on the working side. (2) The temporalis on the balancing side and both
masseters after a 50-100 ms delay. (3) Both masseter and medial pterygoid muscles.
6. Lavelle, Christopher L.B. (1988). Applied Oral Physiology || Mastication. , (), 12–24.
35. • Mandibular movements during
mastication
During opening, there is usually a lateral mandibular shift to the working (functional) side. The mandible
then swings back during closure into the intercuspal position.
The working-side condyle moves laterally during the opening phase, whereas the opposing condyle on
the balancing side moves medially downwards and forwards.
The working-side condyle rapidly resumes its position within its fossa early in the closing phase, whereas
the balancing-side condyle moves back into its fossa in the later phase of closing.
Such mandibular movement patterns are not fixed, however, but may be affected by a number of factors,
including food bolus consistency, individual masticatory habits and the state of the dentition.
35
6. Lavelle, Christopher L.B. (1988). Applied Oral Physiology || Mastication. , (), 12–24.
36. • Tooth contacts during mastication
Early studies35 suggested that the teeth do not actually contact during mastication.
It was speculated that food between the teeth, along with the acute response of the neuromuscular
system, prohibits tooth contacts.
Other studies, however, have revealed that tooth contacts do occur during mastication.
When food is initially introduced into the mouth, few contacts occur.
As the bolus is broken down, the frequency of tooth contacts increases.
36
Tooth
contacts
during
mastication
Gliding (60%)
which occurs as the cuspal inclines pass by each
other during the opening and grinding phases
mastication
Single (56%)
which occurs in the maximum intercuspal
position
5. JEFFREY P
. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p42
37. 37
The average length of time for tooth contact during mastication is 194 ms.
It has even been demonstrated that the occlusal condition can influence the entire chewing
stroke.
During mastication the quality and quantity of tooth contacts constantly relay sensory
information back to the CNS regarding the character of the chewing stroke.
This feedback mechanism allows for alteration in the chewing stroke according to the
particular food being chewed.
Generally, tall cusps and deep fossae promote a predominantly vertical chewing stroke,
whereas flattened or worn teeth encourage a broader chewing stroke.
38. 38
When the posterior teeth contact in undesirable lateral movement, the malocclusion
produces an irregular and less repeatable chewing stroke
Normal persons masticate with chewing strokes that are well rounded, are more repeated,
and have definite borders.
When the chewing strokes of persons with TMJ pain are observed, a less frequent repeat
pattern is noted.
The strokes are much shorter and slower and have an irregular pathway.
These slower, irregular but repeatable pathways appear to relate to the altered functional
movement of the condyle around which the pain is centered.
9. Anderson DJ, Picton DCA: Tooth contact during chewing, J Dent Res 36:21-26, 1957.
39. • Forces of mastication
The maximum biting force that can be applied to the teeth varies from individual to individual. It is
generally found that males can bite with more force than can females.
it was reported that a female’s maximum biting load ranges from 79 to 99 lb (35.8 to 44.9 kg), whereas
a male’s biting load varies from 118 to 142 lb (53.6 to 64.4 kg).The greatest maximum biting force
reported is 975 lb (443 kg).
It has also been noted that the maximum amount of force applied to a molar is usually several times that
which can be applied to an incisor. In another study44 the range of maximum force applied to the first
molar was 91 to 198 lb (41.3 to 89.8 kg), whereas the maximum force applied to the central incisors was
29 to 51 lb (13.2 to 23.1 kg).
The maximum biting force appears to increase with age up to adolescence. It has also been
demonstrated that individuals can increase their maximum biting force over time with practice a high
percentage of tough foods will develop a stronger biting force. This concept may explain increased biting
strength in the Eskimo population.
39
5. JEFFREY P
. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p43
40. 40
Increased biting strength may also be attributed to facial skeletal relationships. Persons
with marked divergence of the maxilla and mandible generally cannot apply as much
force to the teeth as can persons with maxillary and mandibular arches that are relatively
parallel.
A study by Gibbs et al.50 reports that the grinding phase of the closure stroke averaged
58.7 lb on the posterior teeth. This represented 36.2% of the subject’s maximum bite
force.
The tooth pain or muscle pain reduces the amount of forced used during chewing.
During chewing greatest amount of force is placed on the first molar region.
With tougher foods, chewing occurs predominantly on the first molar and second
premolar areas.
The biting force of subjects with complete dentures is only one fourth that of subjects
with natural teeth.
Edentulous bite force at canine/premolar area =25.8lbs
8. Brekhus PH: Stimulation of the muscles of mastication, J Dent Res 20:87-92, 1941.
41. • Role of soft tissues in mastication
As food is introduced into the mouth, the lips guide and control intake, as well as seal off the oral cavity.
The lips are especially necessary when liquid is being introduced.
The tongue plays a major role, not only in taste but also in maneuvering the food with In the oral cavity
for sufficient chewing.
When food is introduced, the tongue often initiates the breaking- up process by pressing it against the
hard palate. The tongue then pushes the food onto the occlusal surfaces of the teeth, where it can be
crushed during the chewing stroke.
41
JEFFREY P
. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p44
42. 42
During the opening phase of the next chewing stroke, the tongue repositions the partially
crushed food onto the teeth for further breakdown. While it is repositioning the food from
the lingual side, the buccinator muscle (in the cheek) is accomplishing the same task from
the buccal side. The food is thus continuously replaced on the occlusal surfaces of the teeth
until the particle size is small enough to be swallowed efficiently.
The tongue is also effective in dividing food into portions that require more chewing and
portions that are ready to be swallowed. After eating, the tongue sweeps the teeth to
remove any food residue that has been trapped in the oral cavity.
JEFFREY P. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND OCCLUSION, EDITION 6 p44
43. • Chewing reflex
43
Presence of a bolus of food in mouth first initiates reflex
inhibition of the muscle of mastication , which allows lower jaw
to drop.
The drop in turn initiates a stretch reflex of the jaw muscles
which leads to rebound contraction.
Automatically raises the jaw to cause closure of teeth, but it also
also compresses the bolus again against the linings of mouth,
which inhibits jaw muscles once again, allowing the jaw to drop
and rebound another time.
44. • Control of mastication
44
Action of mastication is mostly a reflex process.
It is carried out voluntarily also.
The center for mastication is situated in medulla and cerebral cortex.
Responsible nerve for reflex mechanism : mandibular division of 5th cranial (trigeminal) nerve.
7. Sembulingam K, Sembulingam P
. Essentials of medical physiology. JP Medical Ltd; 2012 Sep 30.
45. • Mastication in denture bearer
The quality of the prosthetic service may have a direct bearing on the denture wearer’s
masticatory performance. The maximal bite force in denture wearers is five to six times less
than that in dentulous individuals. Edentulous patients are clearly handicapped in masticatory
function, and even clinically satisfactory complete dentures are a poor substitute for natural
teeth.
The pronounced differences between persons with natural teeth and patients with complete
dentures are conspicuous in this functional context:
(1) the mucosal mechanism of support as opposed to support by the periodontium;
(2) the movements of the dentures during mastication;
(3) the progressive changes in maxillomandibular relations and the eventual migration
of dentures; and
(4) the different physical stimuli to the sensor motor systems
45
10.Kumar L, Biomechanics and clinical implications of complete edentulous state, Journal of Clinical Gerontology & Geriatrics (2014),
46. 46
The denture-bearing tissues are constantly exposed to the frictional contact of the overlying denture
bases. Dentures move during mastication because of the dislodging forces of the surrounding
musculature. These movements manifest themselves as displacing, lifting, sliding, tilting, or rotating of the
dentures. Furthermore, opposing tooth contacts occur with both natural and artificial teeth during function
and parafunction when the patient is both awake and asleep.
Apparently, tissue displacement beneath the denture base results in tilting of the dentures and tooth
contacts on the nonchewing side. In addition, occlusal pressure on the dentures displaces soft tissues of
the basal seat and allows the dentures to move closer to the supporting bone. This change of position
under pressure induces a change in the relationship of the teeth to each other.
10. Kumar L, Biomechanics and clinical implications of complete edentulous state, Journal of Clinical
Gerontology & Geriatrics (2014),
47. • Myofascial pain dysfuntion
Etiology:
1. Occlusal disturbances
2. Intracapsular disorders
3. Emotional turmoil
4. Direct or indirect trauma
5. Spine pathology
6. Psychogenic influences like stress and
strain
7. Habits like bruxism
Pathophysiology
47
12. Dr. Preethi Poonja et al, ARC Journal of Dental Science Volume 3, Issue 3, 2018, PP 1-4 ISSN No. 2456-0030
48. 48
• Mpds trigger points
Trigger points are small exquisitely tender areas, which causes pain to the distant region,
called the referred Pain Zone.
They are activated by pressure, movement, change of barometric pressure and tension
TAUT BAND- It is the group of tense muscle fibers extending from a trigger point to the
muscle attachments, the tension being caused by contraction knots that are located in trigger
point region
• Clinical features
TMJ sounds
Impaired or irregular mandibular movement
Limitation in mouth opening
Preauricular pain
Facial pain
Headaches
Jaw tenderness on function
49. 49
• A trigger point in the occipital belly of
the occipitofrontalis muscle can produce
referred headache pain behind the eye.
• Trigger points located in the trapezius muscle
refer pain to behind the ear, the temple, and the
angle of the jaw.
• Trigger points located in the sternocleidomastoideus
refer pain to the temple area.
51. • Prosthetic management of masticatory
muscle disorder
AN OCCLUSAL APPLIANCE is a removable device, usually made of hard acrylic, which
fits over the occlusal and incisal surfaces of the teeth in one arch, creating precise
occlusal contact with the teethof the opposing arch.
Occlusal appliances have several uses, one of which is to temporarily introduce a stable
occlusal condition that can alter neuromuscular reflex activity, leading to improvement
in certain muscle pain disorders.
Two types of occlusal appliance can be used:1) stabilization appliance
2)anterior positioning appliance
51
11. Ekberg E, Nilner M: Treatment outcome of appliance therapy in temporomandibular disorder patients with
myofascial pain after 6 and 12 months, Acta Odontol Scand 62(6):343–349, 2004.
52. 52
The stabilization appliance is sometimes called a muscle relaxation appliance because it is
primarily used to reduce muscle
The anterior positioning appliance is sometimes called an orthopedic repositioning
appliance, since its goal is to change the position of the mandible in relation to the cranium.
Stabilization splint
53. • An occlusal view of a well-
adjusted stabilization appliance
when the patient closes in the
musculoskeletally stable position
(centric relation). All centric
relation contacts are even and on
flat surfaces.
53
54. • A, Relationship of the anterior teeth to
the anterior stop in centric relation.
However, this position does not reduce
pain or clicking associated with the disc
displacement.
• B, The patient’s mandible protrudes
slightly until an opening and closing
movement occurs that eliminates the
painful clicking. The contact area on the
anterior stop is marked with articulating
paper in this position.
• C, The mark labeled as CR is the
musculosk-eletal stable position of the
condyle (centric relation), and the mark
labeled AP is the anterior therapeutic
position of the condyle that eliminates
the TMJ clicking.
54
55. • Conclusion
Mastication is oral motor behavior reflecting central nervous system commands,
and many peripheral sensory inputs to modulate the rhythmic jaw movements.
It is the main function of the dentist to ensure that patients can bite and
masticate their food in an efficient manner.
The problem is that there is still a dearth of information concerning the 'proper’
method for the opposing teeth to meet together during chewing. As a result,
great care has to be taken to ensure that the patient's masticatory ability is
improved, rather than worsened, by dental treatment.
55
56. • References
1. BD Chaurasiya’s human anatomy; temporal and infratemporal region; 4th edition, CBS
Publisher 2004.
2. Wheeler’s dental anatomy, physiology and occlusion;9th edition;2012
3. Basit H, Tariq MA, Siccardi MA. Anatomy, Head and Neck, Mastication Muscles.
StatPearls [Internet], 2020.
4. Helmenstine, Anne Marie, Ph.D. "Mastication: Definition and Functions." ThoughtCo,
Aug. 29, 2020.
5. JEFFREY P
. OKESON MANAGEMENT OF TEMPOROMANDIBULAR DISORDERS AND
OCCLUSION, EDITION 6.
6. Lundeen HC, Gibbs CH: Advances in occlusion, Boston, 1982, John Wright PSG
56
57. 57
7. Sembulingam K, Sembulingam P
. Essentials of medical physiology. JP Medical Ltd; 2012 Sep30.
8. Brekhus PH: Stimulation of the muscles of mastication, J Dent Res 20:87-92, 1941.
9. Anderson DJ, Picton DCA: Tooth contact during chewing, J Dent Res 36:21-26, 1957.
10. Kumar L, Biomechanics and clinical implications of complete edentulous state, Journal of Clinical
Gerontology & Geriatrics (2014),
11. Ekberg E, Nilner M: Treatment outcome of appliance therapy in temporomandibular disorder patients
with myofascial pain after 6 and 12 months, Acta Odontol Scand 62(6):343–349, 2004.
Masticatory Myofascial pain- Mastication muscle pain disorders are similar to other skeletal muscle disorders in other parts of the body. It is characterized by a dull regional ache with the presence of trigger points when palpated which produces referred pain, that increases during the function.
Masticatory myalgia- It is characterized as a dull persistent ache overlying the jaw and temple muscles with occasional reference to other structures such as head, neck, ear, and teeth. Symptoms can also include a restricted opening, fatigue, and stiffness. Signs include tenderness of the muscles with limited ROM. Localized myalgia presents as sore or aching muscles, usually affecting bilaterally at the region of masseter and temporalis muscles.
Masticatory myospasm- Myospasm also known as muscle cramp is an acute condition resulting from a sudden, involuntary and continuous tonic contraction of the muscle. It is characterized by acute shortening of a single muscle and may lead to trismus (lockjaw), pain on movement, severely limited range of motion of the mandible. These characteristics coupled with their sudden onset at rest allow the clinician to differentiate myospasm from other masticatory muscle disorders.
Myofibrotic contracture- It involves a painless shortening of muscle as a result of fibrosis in and around the remaining contractile muscle tissue. It follows an infectious process or trauma. There are limited mouth opening and unyielding resistance to passive jaw muscle stretch.
Myositis- Myositis is an inflammatory condition of the muscles caused by acute trauma or infection It is characterized by swelling, redness overlying skin and increases the temperature over the affected area. It results in jaw dysfunction and limited range of movement.