OCDB Revision Lecture Handouts (PDF)

04/03/2021 Oral and craniofacial developmental biology (Revision lecture) Ana Angelova Volponi, DDS, PhD Lecturer in Regenerative Dentistry, Faculty of Dentistry, Oral & Craniofacial Sciences King’s College, University of London 1 REVISION of OCDB topics Unit 2: Embryology and Development Dental Tis...

04/03/2021 Oral and craniofacial developmental biology (Revision lecture) Ana Angelova Volponi, DDS, PhD Lecturer in Regenerative Dentistry, Faculty of Dentistry, Oral & Craniofacial Sciences King’s College, University of London 1 REVISION of OCDB topics Unit 2: Embryology and Development Dental Tissues 2 1 04/03/2021 Embryogenesis -What are the stages of our Development? -Define endoderm, mesoderm and ectoderm -How the germ layers are formed during embryogenesis? -List the derivates of each germ layer …. -Can you name the germ layer origin of different facial structures -How the 3D shape of the body and head forms from three germ layer -How the head to tail axis is set up 3 4 2 04/03/2021 Pharyngeal arch development Ectoderm Different tissue of the face have different origins https://www.youtube.com/watch?v=fp3Z_Y--0jo Endoderm What part of the face each facial primordial gives rise to in the adult face -Which facial primordia fuse to generate: The upper lip Primary Secondary palate Mesenchyme https://www.youtube.com/wat ch?v=4LQJIf0XLP0&t=69s 5 How many arches there are? How are they numbered? What is the fate of the pharyngeal arches ? 6 3 04/03/2021 Mechanisms of post-natal growth Can you make a difference between endochondral and intramembranous ossification and recall which bones develop in cartilage and which in membrane. Describe the four methods of bone growth, sutural growth, endochondral growth i.e. growth plate and growth by bone remodelling and via secondary cartilage. Know the key differences between primary and secondary cartilage Define the three basic regions of the skull: cranial vault, cranial base, face Know the features of the skull and face at birth Know how the shape of bones changes postnatally i.e. mandible and maxilla Know the mechanisms of post-natal growth of the cranial vault, cranial base and face Know how these regions differ in the rates and timing of post-natal growth. Use revision sources on KEATS 7 TMJ development Describe how the TMJ forms during normal development. Review of developmental defects associated with the TMJ Review of genes thought to play a role in TMJ formation 8 4 04/03/2021 Early tooth development Recall the basic stages of tooth development as well as the features and timing of each stage. Define cranial neural crest cells and ectomesenchyme. Describe origin of epithelium and mesenchyme involved in tooth development. Use revision sources on KEATS Use Virtual Histology Lab 9 Embryonal origin of different dental tissues: Epithelium ? / Mesenchyme? 10 5 04/03/2021 Late tooth development What is the function and fate of the enamel organ, dental papilla and dental follicle? (what develops from each of these structures? Recall location and features of primary and secondary enamel knots. When (which stage) do the enamel knots appear? Where are these positioned? What is specific about the enamel knots Can you describe initiation of development of secondary dentition for teeth with and without deciduous precursors? How tooth crown shape is established in mono- and multicusped teeth. (revise in Tooth Morphogenesis lecture too) Define the dental lamina and its fate. What is the cellular origin of odontoblasts and ameloblasts. 11 Tooth Embryonic development 12 6 04/03/2021 Tooth Morphogenesis Understand how tooth type is controlled -How do you make an incisor rather than a molar. Understand the role of the enamel knot in shaping the developing tooth The primary enamel knot is induced at the bud stage of tooth development by signals from the mesenchyme This leads to high proliferation outside the enamel knot and low proliferation within the enamel knot. The result is a folding of the dental epithelium. The Enamel knot expresses growth factors but does not express the receptors and so can not respond to its own signal. Do Molars have primary enamel knot? Do incisors have secondary enamel knot? 13 Signaling Pathways in tooth development Recall different types of cell signalling Understand the basic principles of signal transduction systems. 14 7 04/03/2021 Root development and eruption Define Hertwig’s root sheath and explain its function in root development. Explain how single and multirooted teeth form and how accessory root canals develop. What is the origin of epithelial cell rests. (Mallasez cells?) Illustrate the stages of tooth eruption in teeth lacking predecessors. What is reduced enamel epithelium and understand its role in the development of the junctional epithelium? What is eruption, what are its rates throughout life? What is active eruption versus passive eruption? Describe the possible mechanisms whereby an eruptive force may be produced: tension versus pressure. 15 TOOTH AND ITS SUPPORTING TISSUES lectures revision 16 8 04/03/2021 Structure and function of enamel Understand the enamel structure and its anatomical features designed to withstand biting and wearing forces. Describe the enamel prism structure, incremental lines, diazones and parazones and their importance for adhesive dental materials. Understand the specific features of Enamel-dentin junction, tufts and lamellae and their clinical relevance. 17 Amelogenesis Describe the composition and structure of enamel Understand the stages of enamel formation (amelogenesis), the physiology of cells involved in this process and secreted matrix proteins, the process of maturation and mineralisation of the enamel. What are ameloblast and what is their embryonal origin? (epithelial or mesenchymal?) What are Tomes’s processes? Describe the clinical considerations of maturation changes in Increm ental line enamel (fluoride and tetracycline staining), as well as mechanisms of adhesion of dental materials to enamel. Can you describe the process and cellular involvement? 18 9 04/03/2021 Dentine Define all the terms used to describe dentine Understand why they are important Define and explain all the growth lines in dentine State the difference between primary, secondary and tertiary dentine Understand the clinical aspects of the structure of dentine Use Virtual Histology resource to explore and annotate your slide ! 19 Dentinogenesis Consider the differentiation of odontoblasts State the role of odontoblasts in secreting and modifying the protein matrix and the mineralisation of the matrix State the different mechanisms by which mineralisation occurs State the molecular features of the biological process involved in tertiary dentine formation 20 10 04/03/2021 Dental pulp Disposition of the tissue; Functions; Composition Arrangement of outer and inner regions of pulp: odontoblast layer; cell free zone; Raschkow's nerve plexus; subodontoblastic capillary plexus - cell rich zone - homogeneous bulk of pulp - centre containing large nerves - blood vascular system. Cells of dental pulp: odontoblasts; fibroblasts; defence cells. Fibres and ground substances of the dental pulp; Blood vascular system; Nervous elements in the dental pulp; Age changes; Reactions to stimuli; Pulp/dentine sensitivity; Clinical aspects Use Virtual Histology resource to explore and annotate your slide ! A 21 Dental pulp is a connective tissue situated within rigid encasement of mineralised dentin. Incased in the dental chamber, the dental pulp has limited nerve and blood supply. Connective tissue that contains different cell populations. Apical foramen 22 11 04/03/2021 Age-related changes of dental pulp Dimensional changes: -Reduction in size, decreased volume of dental pulp chamber and root canal. In Coronal part, there is a continious apposition of dentin occlusally and in the furcation area. http://pocketdentistry.com/12-endodontic-management-of-the-aging-patient/ Is this primary, secondary or tertiary dentin? 23 Histological age-related changes of the dental pulp young old http://pocketdentistry.com/12-endodontic-management-of-the-aging-patient/ 24 12 04/03/2021 Structure of cementum and alveolor bones Explain the main features of alveolar bones (maxilla and mandible) Know the anatomy! How do the bones change through life and what are the underlying mechanisms (be able to describe the apposition and resorption as processes and the cells involved in remodelling of the bones) What is called lamina dura? What are resting lines and reversal lines? Define: cementoblast & cementocyte Describe different types of cementum and where are these localised ? Can you list the constituents of cementum and compare its composition with that of bone? Can you distinguish between acellular and cellular cementum. Can you list the five cell types found in bone, giving their structure and function? Can you illustrate the tooth/alveolar process relationships? Can cementum be repaired ? 25 Structure and function of periodontal ligament-learning outcomes Describe in a detailed overview the anatomical structure of the periodontal ligament. (fibrous, cellular, ground substance com ponents of this specialised connective tissue) Is Periodontal ligament part of the Periodontium? What are the other parts of Periodontium? Where is Periodontal ligament positioned and which types of fibers we find there? Whate are Sharpey’s fibers? Where do these fibres attach? Do you know the functions of the periodontal ligament during tooth support, eruption and mastication. 26 13 04/03/2021 Periodontal Ligament D-dentin; C-cementum; V-blood vessels; F-fibroblats White arrows = cementoblast Red arrows = Epithelial rests of Malassez Green arrow = PDL 27 (Collagen fibres attached to Bundle bone) 28 14 04/03/2021 Gingiva and periimplant tissue Can you describe anatomy and function of gingival tissues, and of those tissues around the emerging dental implant and restoration. To be able to compare and contrast these tissue types To understand the basics of how these tissues may change in the presence of inflammation. 29 Periodontium Bundle bone http://pocketdentistry.com/1-a-whistle-stop-tour-of-the-periodontium/ 30 15 04/03/2021 Dental Stem cells and Regenerative approaches in dentistry Describe the main properties of stem cells and what we need to define stem cells? What are embryonic stem cells (ESCs) and how are these derived? What are adult/somatic stem cells and what is their function and properties? What are Induced Pluripotent Stem (iPSCs) cells and how are these derived? Describe the tooth as an accessible source of different stem cells, and describe similarities and differences among different dental stem cells. (Can you tell what are: SHED cells; DPSCs; PDLScs; SCAP; Follicular stem cells; Gingival (fibroblast)SCs; …?) Understand the new approaches in dentistry: repair and regenerate -How does the dentin repair? What happens in Dental pulp following injury? 31 Use all these resources for your revision, don’t use only some…! Summary In order to support your learning of OCDB topics, the following resources ARE available for the revision: All video recorded lecture are available on KEATS Histology Workshop has been organised to strengthen the learning of Tooth development and Dental tissues. Additional revision excercises (to revise Development lectures and Anatomy) are set up and available on KEATS This is an additional REVISION LECTURE Please give your feedback on KEATS ! …it takes less than a minute ! 32 16 04/03/2021 Additional revision excercises (to revise Development lectures and Anatomy) are set up and available on KEATS 33 Additional revision excercises (to revise Development lectures and Anatomy) are set up and available on KEATS 34 17 04/03/2021 Additional revision excercises (to revise Development lectures and Anatomy) are set up and available on KEATS 35 Formative exam 2 will contain MCQs from this Unit, along with other modules: BMS1 Introduction to Clinical Skills Dentistry in Society BMS2 36 18