Created by Evian Chai
over 4 years ago
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Question | Answer |
Label the Alveolar Bone | A: Body B: Ramus C: Incisive Fossa D: Mental Foramen E: Angle F: External oblique line G: Coronoid process H: Condyle I: Mental Protuberance |
What are the functions of alveolar bone? (4) | 1. Muscle attachment 2. Bone marrow 3. Reservoir for ions (Ca2+) 4. Plasticity+remodelling |
What does the alveolar depend on for development? Maintenance? Retain bone mass? | 1. Tooth eruption 2. Tooth retention 3. Functional stimuli |
When does the alveolar bone develop? | Second month of fetal life with root formation/eruption of teeth |
What are the 3 layers inside alveolar bone, from outside to inside? | 1. Outer cortical plates (cortical) 2. Central spongiosa (spongy) 3. Bundle bone lining alveolus (cortical) |
What attaches bundle bone to the PDL? | Collagen fibres |
Where is the outer cortical plate thicker? | Mandible>maxilla Premolar/molar regions |
What are Sharpey's Fibers? What orientation are they to bundle bone? | Fibers of the PDL that embed in bone/cementum Perpendicular to bundle bone (vs. parallel) |
What is the lamina dura? | Thick line on radiograph due to lack of trabeculations |
What is the cribiform plate in the alveolar bone? | The preforated structure that allows for blood vessels/nerves |
What does the interradicular septum separate? | Roots on multirooted teeth |
What does the interdental septum separate? | Two adjacent teeth |
What is the alveolar bone innervated by? | The trigeminal nerve |
What does the trigeminal nerve contain? (4) | 1. Mesencephalic sensory neurons of trigeminal nerve 2. Motor nucleus 3. Sensory nucleus 4. Spinal sensory trigeminal nucleus |
What does the trigeminal ganglion split into? (3) | Ophthalmic branch Maxillary branch Mandibular branch |
What in the alveolar bone allows nerve/blood to pass through? | Canals and foramens |
What is the arrangement of the trabeculae in the maxilla? | Irregular (Type 2) More trabecular More porous |
What is the arrangement of the trabeculae in the mandible? | Regular/horizontal (Type 1) Less trabecular Less porous |
What is the relationship between tooth loss and bone? | Leads to bone loss (eg. shortened jaw) |
What is the resting line? | Where osteoblasts stop making bone |
What is the reversal line? | Where osteoclasts start reabsorbing bone |
What is cementum? | Bone like tissue covering ROOTS of teeth Thickest at apex Unvascularised |
What are the functions of cementum? (4) | 1. Joins enamel at cervix of teeth 2. Anchor teeth to bony walls of tooth socket 3. Anchor gingival/periodontal fibres 4. Protects dentine |
What forms cementum? Where do they originate? | Cementoblasts 3 models (pulp cells to odontoblasts to cementoblasts OR HERS-->Epithelial mesenchyme transformations OR dental follicle cells) |
What is the composition of cementum? | 65% inorganic hydroxyapatite 23% organic (type 1 collagen, proteoglycans, glycoproteins) 12% H20 |
What is the ranking of inorganic material from high to low of bone, cementum, dentine and enamel? | Enamel (90%)>Dentine(70%)>Cementum(65%)>Bone (60%) |
What are the four types of cementum? | 1. Acellular, afibrillar cementum: -small islands on enamel 2. Acellular, extrinsic fibre cementum 3. Cellular intrinsic fiber cementum 4. Cellular mixed fiber cementum |
What are the differences between cellular and acellular cementum in terms of cementocytes, deposition rate, incremental lines, and precementum layer? | 1. Acellular has no cementocytes 2. Acellular has slow deposition 3. Acellular has close incremental lines 4. Acellular has THIN precementum layer |
What are the differences between extrinsic fibrillar and intrinsic fibrillar in terms of orientation to cementum, origin, and function? | 1. Extrinsic comes from PDL and is perpendicular to cementum (eg. Sharpey's) while intrinsic is parallel 2. Intrinsic is produced by cementoblasts 3. Extrinsic anchors teeth, intrinsic found near repair |
Does the cementum remodel? | No, unlike bone |
What is hypercementosis? | Too much cementum creates bulge in tooth roots |
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