DEN 020 Oral Histology and Embryology Student Activity Sheet #20 PDF

DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________...

DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________ Class number: _______ Section: ____________ Schedule: _____________________________________ Date: _______________ LESSON TITLE: TEMPOROMANDIBULAR JOINT (TMJ) MATERIALS: Ballpens, erasers, pencils, LESSON OBJECTIVES: highlighter pens and module At the end of the day, you will be able to: 1. Describe the histology of the temporomandibular joint. REFERENCES: 2. Discuss the clinical significance of the temporomandibular joint. Nanci, A. 2019. Ten Cate’s Oral Histology. 9th Edition. Singapore: Elsevier (Singapore) Pte. Ltd. PRODUCTIVITY TIP: Good day stuDENTIST! You are about to start your module. Do short stretching and breathing exercises. After you are done, sit down, be comfortable and say a short prayer. You are now ready to start your work. Enjoy and learn! A. LESSON PREVIEW / REVIEW Introduction (2 minutes) The bones involved in the articulation of the lower jaw with the cranium and upper facial skeleton are the mandible and the temporal bone, and the joint therefore is designated the temporomandibular joint (TMJ). The joint is unique to mammals. In other vertebrates the lower jaw is compound, consisting of several bones including the dentary bone (bearing teeth) and the articular bone (formed from the posterior part of Meckel’s cartilage), and articulates with the quadrate bone of the skull. As mammals evolved, the compound lower jaw was reduced to a single bone (the mandible) bearing teeth that articulate with the newly developed articulating surface on the temporal bone. Thus in phylogenetic terms the TMJ is a secondary joint. The primary vertebrate jaw joint is still present in human anatomy (as the incudomalleolar articulation), with the bones involved (incus and malleus) now positioned in the middle ear (Nanci, A. 2019. Ten Cate’s Oral Histology. 9th Edition. Singapore: Elsevier (Singapore) Pte. Ltd. pp. 289). Learn and Enjoy! Activity 1: What I Know Chart, part 1 (3 minutes) What I Know Guide Questions: What I Learned (Activity 4) 1. What I know about the TMJ? 2. What are the parts of the TMJ? 3. What are the functions of the TMJ? This document is the property of PHINMA EDUCATION  DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________ Class number: _______ Section: ____________ Schedule: _____________________________________ Date: _______________ B. MAIN LESSON Activity 2: Content Notes (13 minutes) Learn and Enjoy! Please read the Content Notes. This will give you a preview on the topic and tasks that will follow in this module. You can use your highlighter pen to shade important keywords. TEMPOROMANDIBULAR JOINT  is a joint on each side of the head that allows for movement of the mandible during mastication, speech and respiration  ginglymoarthrodial joint, referring to its dual compartment structure and function  it develops in the 11th -12th week of prenatal development during the growth of the associated ligaments, muscles and bone Bony Components  Condyle of the mandible, Glenoid fossa and Articular eminence  These bony components are covered with fibrocartilage that consists of an outer fibrous layer and an inner layer of hyaline cartilage. Disc or Meniscus  Temporodiscal compartment or an upper compartment where gliding movement takes place.  Condylodiscal compartment of a lower compartment where hinge movement takes place. Synovial Membrane  inner lining of the capsular ligament responsible for the secretion of the synovial fluid that functions to lubricate the joint. Functions of the Temporomandibular Joint (Source: Bordoni, B. and Varacallo, M. 2020. Anatomy, Head and Neck, Temporomandibular Joint. USA: StatPearls Publishing LLC.)  When the mouth opens there is a combination of rotational movement of the discomandibular space and action of the translational discotemporal space; the rotation occurs before the translation.  The condyle can move laterally through a rotation and then an anterior sliding of the same condylar structure, and an anterior translation/rotation in the medial direction of the opposite condyle.  The condyle can move backward, while the opposite condyle slides forward.  The bilateral or ipsilateral TMJ protrusion occurs by anterior sliding.  The complex movements of TMJ allow multiple functions including: Chewing, Sucking, Swallowing, Phonation, Facial expressions, Breathing, Protrusion, retrusion, lateralization of the jaw, Opening the mouth and Maintain the correct pressure of the middle ear. Embryology of the Temporomandibular Joint (Source: Bordoni, B. and Varacallo, M. 2020. Anatomy, Head and Neck, Temporomandibular Joint. USA: StatPearls Publishing LLC.) This document is the property of PHINMA EDUCATION  DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________ Class number: _______ Section: ____________ Schedule: _____________________________________ Date: _______________  TMJ derives from the first pharyngeal arch, where we can recognize a mesodermal part (muscles and vessels) and mesenchyme (from neural crests) for bones and cartilages. The development of TMJ divides into three stages: the blastemic stage; the cavitation stage and lastly, the maturation stage. Blastemic stage. It begins in the seventh/eighth week of gestation, where the formation of the glenoid fossa and condylar blastema occurs (a group of cells that remain long undifferentiated and, proliferating, give rise to sketches of organs). Cavitation stage. The formation of the lower joint space begins. The blastemis start to differentiate into multiple layers, to form the lower synovial layer and what will become the joint disk; this happens between the ninth and tenth weeks of gestation. Maturation stage. The upper joint space begins to form towards the eleventh week of gestation. TMJ will continue to form until the baby is born. Around 17 weeks the joint capsule is formed, while at 19 to 20 weeks the development of the cartilage inside the capsule can be recognized.  The morphology of the glenoid fossa and the condyle will be under the influence of the mechanical forces of the vessels and neighboring muscles. At birth, TMJ, compared to other types of synovial joints, is not fully developed. The jaw will begin to develop from the fourth week. TMJ develops simultaneously with the ear.  The child has a more obtuse mandibular arch, compared to the adult, which has a more angular shape; in the baby, the glenoid fossa is looser and, the cartilage is not yet present, but there will be a fibrous connective tissue. Between 5 and 10 years of age, the condyles grow in a posterior, lateral and upward direction; the joint shape will be further managed by the mechanical forces of the teeth and the chewing muscles. Figures Anatomy of the TMJ Histology of the TMJ This document is the property of PHINMA EDUCATION  DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________ Class number: _______ Section: ____________ Schedule: _____________________________________ Date: _______________ Positions of the TMJ during function Figure (Sources) https://quizlet.com/127262235/oral-histology temporomandibular-joint-flash-cards/ https://pocketdentistry.com/19-temporomandibular-joint/ Activity 3: Skill-building Activities (with answer key) (18 minutes + 2 minutes checking) Identify the lettered structures of the temporomandibular joint histology (10x magnification). Check your answers against the Key to Corrections found at the end of this activity sheet. Write your score on your paper. Good Luck and Enjoy! Answers: A. B. C. D. E. F Activity 4: What I Know Chart, part 2 (2 minutes) Go back to the “What I Know Chart” in Activity 1 and answer the “What I Learned” column. Activity 5: Check for Understanding (5 minutes) This document is the property of PHINMA EDUCATION  DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________ Class number: _______ Section: ____________ Schedule: _____________________________________ Date: _______________ Encircle the most appropriate letter of choice for your answer to the Content Questions as honestly as you can. You can encircle more than one (1) letter for your answer. Let’s go! My Score: _____________ 1. The cavitation stage of TMJ embryology is characterized by: a. formation of the lower joint space begins c. the lower synovial layer will form the joint disk b. blastemis differentiate into multiple layers d. occurs during the ninth and tenth weeks of gestation. 2. Functions of the TMJ include: a. opening the mouth c. phonation b. maintain the correct pressure of the inner ear d. facial expressions 3. The TMJ develops together with this organ: a. mouth c. ears b. nose d. eyes 4. Lubrication for movement of the TMJ discs is brought about by a fluid secreted by: a. retrodiscal membrane c. articular membrane b. discotemporal membrane d. synovial membrane 5. The child has a more obtuse mandibular arch while the adult has a more angular shape: a. angular - reflex c. reflex - acute b. acute - straight d. obtuse - angular STOP! and check your answers against the Key to Corrections found at the end of this Activity Sheet. Write your score/s on your paper. C. LESSON WRAP-UP Activity 6: Thinking about Learning (5 minutes) Work Tracker You are done with this session! Let’s track your progress. Shade the session number you just completed. Think about your Learning: Please answer the following questions: Please rate your activity today by placing a check mark (/) before a choice. Please explain your choice on the blank space beside the table: This document is the property of PHINMA EDUCATION  DEN 020: Oral Histology and Embryology Student Activity Sheet #20 Name: ____________________________________________________________ Class number: _______ Section: ____________ Schedule: _____________________________________ Date: _______________ 1. Boring 2. Not informative 3. Challenging 4. Fair 5. Fun “What details in the content and/or activities were not clear to you?” ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ D. FREQUENTLY ASKED QUESTIONS:  What is the clinical significance of the TMJ? Many pathologies can impact the TMJ and potentially cause varying degrees of clinical dysfunction. These conditions include but are not limited to:  Rheumatoid arthritis: crepitus, limited range of motion, increased stiffness, pain, joint sounds  Psoriatic arthropathy: joint sounds, morning stiffness, pain  Ankylosing spondylitis: joint sounds, pain in the lateral pterygoid muscles, hypertrophy of the masseter muscle, limitation of the ROM  Pain: articular sounds.  Fibromyalgia syndrome: myalgia, pains of TMJ  Muscular pain  Multiple sclerosis: myalgia pains of TMJ, pain during the movement of the mouth Several temporomandibular disorders symptoms (approximately 85-90%) are treated with noninvasive, nonsurgical approaches. Non-invasive approaches include manual physiotherapy and osteopathy, patient education, medication, and splint therapy. (Source: Bordoni, B. and Varacallo, M. 2020. Anatomy, Head and Neck, Temporomandibular Joint. USA: StatPearls Publishing LLC.) KEY TO CORRECTIONS Identification (6 points) Content Questions (10 points) A. articular disk B. glenoid fossa 1. A, B, C, D 2. A, C, D 3. C 4. D 5. D C. condyle of the mandible D. retrodiscal disk or tissue E. lateral pterygoid muscle F. articular eminence RENELSON L. ESGUERRA, BSc, DMD, PhD, DipForOdont, FICCDE Professor Southwestern University PHINMA - College of Dentistry This document is the property of PHINMA EDUCATION