Transcript for:
Understanding Dental Occlusion and Anatomy

Class 1 occlusion is anatomically defined by-relationship of mesiobuccal cusp of permanent 1st molar aligned with the buccal groove of mandibular 1st molar How is class 1 occlusion for patients without 1st molars determined?-maxillary canine fits into facial embrasure between mandibular canine and 1st premolar Overjet-horizontal overlap of maxillary and mandibular teeth Ideal overjet-maxillary teeth are labial to the incisal edges of mandibular teeth Overbite-vertical overlap of the maxillary and mandibular teeth Ideal overbite-incisal edge of the maxillary incisors overlap the incisal third of mandibular incisors Maximum mouth opening-ability to position three fingers into the mouth at once (index, middle, and ring finger of nondominant hand) Interincisal opening range-40 to 50 mm Malocclusion of individual teeth can occur in-mouths of all class jaw relationships Labioversion-tooth out of alignment to the labial/buccal Linguoversion-tooth out of alignment to the lingual Torsiversion-twisted/rotated tooth Supraeruption-overerupted tooth (abnormally long) Infraocclusion-undererupted tooth (abnormally short) Ankylosis-loss of periodontal ligament causes the root cementum to fuse with alveolar bone, preventing eruption Maximal intercuspation-ideal occlusal fit of both arches Posterior crossbites (reverse articulation) occur when-mandibular posterior teeth are positioned too far buccally Posterior crossbites is anatomically defined by-lingual cusps occlude in central fossae of maxillary teeth Anterior crossbites occur when-mandibular anteriors are facial to the maxillary anteriors Severe overbite-maxillary anteriors completely cover the mandibular anteriors Anterior open bite-posterior teeth occlude but the incisal edges of anterior teeth don’t Anterior open bites are commonly seen in-thumb sucking or pacifier habit Severe overjet-maxillary anterior teeth are considerably anterior to the mandibular incisors Class II malocclusion-mandible is positioned distal from ideal occlusion Class II malocclusion is anatomically defined as-distobuccal cusp of the maxillary first molar aligns with the buccal groove of the mandibular 1st molar How is the mandible positioned in class II occlusion?-retruded Retrognathic profile-receded mandible in which the buccal groove of the mandibular 1st molar is far distal to the mesiobuccal cusp of the maxillary 1st molar Class II, division 1 malocclusion-severe horizontal overjet/flaring of maxillary incisors Class II, division 2 malocclusion-retruded maxillary central incisors with slightly flared lateral incisors Prognathic profile-protruded mandible in which the mesiobuccal groove of the mandibular 1st molar is far mesial to the mesiobuccal cusp of the maxillary 1st molar Class III malocclusion-mandible is positioned facially from ideal occlusion Class III malocclusion is also known as-underbite, anterior crossbite What forms the TMJ?-mandibular condyle articulates with the articular fossa of the temporal bone What structure is found between the mandibular condyle and articular fossa?-articular joint disc padded with a thick layer of fibrous tissue acting as a shock absorber Condylar subluxation-dislocation of the mandible in the upper joint compartment Protrusion of mandible-forward movement Mandibular lateral translation (deviation)-left, right, downward movements when chewing; gliding and rotation Power stroke-during mastication, a movement from a laterally deviated position back to the midline to move food from the cheeks Working side-side of the mouth in which the mandible moves/chews Nonworking side-side of the mouth opposite of the working side Deglutition-voluntary act of swallowing which the tongue pushes a bolus into the pharynx followed by peristalsis Parafunctional contacts-clenching and bruxing Desmosome-intercellular junction; in tissue injury, junctions are released and reattach in new locations Hemidesmosome-an attachment of a cell to an adjacent noncellular surface Functions of the cell membrane-exocytosis, endocytosis, phagocytosis Exocytosis-active transport of material from a vesicle within the cell into the extracellular environment OUTSIDE the cell Endocytosis-uptake of materials from the extracellular environment INTO the cell Phagocytosis-form of endocytosis where the cell membrane invaginates, engulfs, and enzymatically digests waste or foreign materials Nucleolus produces-ribosomal RNA (rRNA) and the nucleotides of two other types of RNA. Mitochondria provides-chief source of energy for the cell What is Kreb’s cycle or hydrogen pathway?-aerobic cellular respiration transforms chemical energy bond of nutrients into adenosine triphosphate (ATP) Cristae-inner folds in mitochondria increase the surface area Produced in the nucleolus from rRNA-ribosomes Where can ribosomes be found?-Within the mitochondria, free-floating in cytoplasm, bound to outer nuclear membrane, bound to surface of the rough ER Proteins synthesized on free polyribosomes are used in-transcription of mRNA Proteins synthesized by rough ER are used in-other sections of the cell or outside the cell Smooth endoplasmic reticulum produces-steroids Rough endoplasmic reticulum produces-proteins Primary functions of ER-modification, storage, segregation, and transport of proteins Golgi complex is responsible for-modifying and packaging a variety of proteins to cell’s surface in a single vesicle to be exocytosed from the cell Synthesis site for lysosomes-golgi complex Main enzyme in lysosomes-hyaluronidase What vitamins stabilize the lysosome’s membrane?-A, E, Zinc Microfilaments-threadlike structures of the cytoskeleton help stabilize the cytoplasm Intermediate filaments-threadlike structures of the cytoskeleton help form keratin & intercellular junctions Microtubules-tubular structures of the cytoskeleton that help microfilaments maintain cell shape, transport intracellular materials Microtubules form the internal framework for-cilia, flagella, centrioles, and the mitotic spindle Phases of interphase-gap 1, synthesis, gap 2 Gap 1 (G1)-resting phase for cell growth and function Synthesis (S)-phase of DNA duplication Gap 2 (G2)-second resting phase that resumes cell growth and function Replication occurs during-interphase Replication produces-two identical copies of DNA Why is interphase critical for mitosis?-replication ensures that each of the daughter cells are identical to each other and also to the parent cell Two layers of basement membrane-basal lamina (superficial) & reticular lamina (deep) Two layers of basal lamina-lamina lucida & lamina densa Lamina lucida-clear layer closer to the epithelium Lamina densa-dense layer closer to the connective tissue Reticular lamina-connective tissue portion of the basement membrane consists of collagen and reticular fibers Interdigitation of epithelial tissue with the deeper connective tissue occurs with formation of-rete ridges Most common cell type in all types of connective tissue-fibroblast Fibroblasts-synthesize protein fibers and intercellular substances that sustain connective tissue White blood cells-inflammatory response and immune response Red blood cells-transport oxygen and carbon dioxide Platelets-function in the clotting mechanism Chondrocytes and chondroblasts-maintain the cartilage matrix Osteoblasts-forms osteoid which matures into bone Osteoclasts-resorbs bone Fibril-subunit of a collagen fiber Fibrous matrix fibers-collagen fibers, type I collagen fibers, elastic fibers Most common type of collagen protein-type I collagen Both loose and dense types of connective tissue are found together in adjoining layers as-connective tissue proper In oral mucosa, the deep connective tissue proper is considered-lamina propria The layer of loose connective tissue, or the papillary layer, forms-connective tissue papillae when the connective tissue interdigitates with the epithelial tissue The loose connective tissue is composed of-elastin and collagen fibers The dense connective tissue is deep to the loose connective tissue and is primarily composed of-protein fibers Dense connective tissue is present in the-lamina propria and dermis Which cells contribute to the turnover of connective tissue proper?-Fibroblasts Turnover time for connective tissue is ________ than epithelial tissue-slower Describe granulation tissue-immature connective tissue with few fibers and a large amount of blood vessels which clinically appears softer, redder, and bleeds easily after injury How is adipose tissue different from other connective tissue?-The cells in are packed tightly together and have little to no matrix What is the function of adipose tissue?-Intracellular fat storage Firm connective tissue is known as-cartilage What role does the perichondrium play with cartilage tissue? Why?-surrounds most of cartilage, and contains blood vessels which supplies the avascular cartilage with nutrients Differentiate between chondroblasts and chondrocytes=Chondroblasts produce cartilage matrix while chondrocytes are mature forms that maintain the matrix Describe the three types of cartilage and where they are located-Hyaline cartilage: avascular, no innervation, containing only collagen fibers, and most common type in the body; located within the embryonic skeleton. Elastic cartilage: similar to hyaline but with elastic and collagen fibers; found in larynx, epiglottis, external ear. Fibrocartilage: transitional cartilage between hyaline and dense CT; found in ligaments and tendons such as the temporomandibular joint What is the difference in interstitial and appositional growth?-Interstitial growth occurs deep within a tissue or organ while appositional growth occurs by adding layers onto tissue masses. How does aging affect cartilage?-cellular reproduction and tissue generation slows, and cartilage becomes less cellular due to chondrocyte death. The tissue loses flexibility and becomes more dense. Bone is the hard and rigid form of-connective tissue. The functions of bone include-movement, attachment for soft tissues, protection, structural support, manufacturer of blood cells, energy bank, and storage for calcium and other minerals. At what level is calcium and phosphorous withdrawn from the bone?-Resorption occurs as injury, appositional growth, or disease occurs, however varying amounts of resorption occur in varying rates dependent on endocrine activity which relies on calcium and phosphate. Growth or injury affect the rate of resorption. Why does bone repair quicker than cartilage?-Bone does not require migration for repair since bone is vascularized. The outer part of the bone is covered by the-periosteum Periosteum is a bilayered dense connective tissue sheath containing-an outer layer with blood vessels and nerves and an inner layer with osteoblasts Compare and contrast compact bone and cancellous bone.-Compact bone is formed by closely apposed layers of about 5 to 20 parallel lamellae embedded with osteocyte which form concentric layers of cylinders called osteons, similar to growth rings of a tree trunk. Cancellous bone matrix consists of a lattice like trabeculae in which the lamellae’s concentric rings are formed into-cone-shaped spicules The endosteum lines the _______-, which is where bone marrow is located.-medullary cavity Bone tissue is ___ inorganic or mineralized material.-60% The inorganic material known as _____ is what gives bone its hardness.-calcium hydroxyapatite Name the cells involved in bone formation maintenance and their function.-Osteocytes: mature osteoblasts in the lacuna extend into canaliculi which allow for cellular interactions between them. Osteoblasts: produce osteoid. Osteoid: bone matrix precursor formed by osteoblasts which later undergoes mineralization Osteocytes become entrapped in the ____ with their cytoplasmic processes located in the___.-canaliculi;canals Compact bone is formed as sheets or lamellae, which are arranged into concentric forms of cylindrical units making up the ________-Haversian system Each of these cylindrical units is called-osteon What are the two ways in which bone can be formed-intramembranous ossification and endochondral ossification Intramembranous ossification-formation of osteoid between two dense sheets of connective tissue that later replaces the outer connective tissue. Where does intramembranous ossification occur?-maxilla and most of the mandible Endochondral ossification-osteoblasts penetrate disintegrating hyaline cartilage where a formed osteoid died and mineralized, then form ossification centers that continue osteoid formation toward the each end of the bone, eventually replacing the cartilage with bone. Where does endochondral ossification occur?-head of the mandibular condyle What cells come together to form an osteoclast?-Macrophage blood cells List three conditions that can affect the integrity of bone-Periodontal disease, Paget disease, Osteoporosis Blood is a fluid ______-connective tissue RBC’s function in-transportation of oxygen and carbon dioxide Platelets function in-clotting mechanism White blood cells are involved in-inflammatory and immune responses Plasma is the ____ portion of blood-fluid Erythrocyte-most common RBC which binds oxygen and carbon dioxide to its hemoglobin for transport throughout the body; because it’s formed directly from bone marrow stem cells via hematopoeisis, it doesn’t undergo mitosis Platelet-Also known as thrombocytes, these small, disc-shaped, non-nucleated formed elements are fragments of megakaryocytes which function in the clotting mechanism Leukocyte-forms from bone marrow stem cells and mature in the bone marrow or other lymphatic organs; these cells also migrate into epithelium or connective tissue to defend against pathogens Neutrophil-first responders in inflammatory response, these phagocytic white blood cells have a shorter lifespan, contain lysosomal enzymes Makes up the greatest number of WBC’s-neutrophils B cells, T cells, and natural killer cells are-lymphocytic cells which account for 25-33% of all WBC’s B cells mature in-lymph nodes and bone marrow T cells mature in the-thymus gland Both B and T cells act as chemical mediators in the immune response by producing-cytokines NK cells are large cells that mature in-bone marrow First to defend against cancerous or virally infected cells, and are therefore not considered immune-responsive type WBC’s-NK cells Plasma cells/immunoglobulins-arise from B cell division during an immune response and mature to produce antibodies, or immunoglobulins in response to a specific antigen Monocyte/Macrophage-circulating monocytes that migrate into connective tissue are considered macrophages, which are the most abundant WBC in connective tissue Eosinophil-phagocytic cells primarily involved in allergic and parasitic responses Basophil-cell that releases bioactive products in response to hypersensitive reactions, making up less than 1% of the WBC count Mast cell-cell local to connective tissues that release bioactive products in response to hypersensitive reactions A chemical mediator produced by B and T cells as part of the immune response is the-cytokine Muscle tissue is derived from-somite There are three types of muscle-Skeletal muscle, Smooth muscle, Cardiac muscle Skeletal muscles may also be referred to as-striated or striped Skeletal muscles are controlled by the-somatic nervous system Smooth muscles are controlled by the-autonomic nervous system List the two main functions of the nervous system-conscious control of a person to move the skeletal muscles and cnconscious control of tissues and organ systems Describe the components of a neuron-axon, dentrite, cell body Axon-myelinated or non-myelinated extension that carries impulses away from the cell body. Dendrite-threadlike process with multiple branches that receives and conducts impulses towards the cell body Cell body-contains the nucleus and provides metabolic support for the entire neuron A synapse is the junction between-two neurons or between a neuron and an effector organ where neural impulses are transmitted by a neurotransmitter Differentiate between afferent and efferent nerves-Afferent: nerve that relays sensory information from the body towards the brain. Efferent: nerve which carries motor information from the brain to control muscles or glands There are two main divisions of the nervous system-the central nervous system and the peripheral nervous system The brain and spinal cord make up the-CNS The autonomic nervous system is part of the-peripheral nervous system The autonomic nervous system is subdivided into-sympathetic nervous system and the parasympathetic nervous system The parasympathetic nervous system is involved with-rest-or-digest responses An example of a fight-or-flight response is -hyposalivation where salivary gland secretion is inhibited The sympathetic nervous system is involved in-fight-or-flight responses 52. Describe the two groups of the autonomic nervous system and give an example of the function of each The sympathetic nervous system neurons are located in the-spinal cord and synapse in ganglia located along the entire length of the vertebral column. For glands of the head and neck region, neurons may be either-preganglionic or postganglionic as their associated fibers and ganglia are located in the head