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{{frontpage
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|pagetitle =Teeth - Pathology
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|pagebody =
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|contenttitle =Content
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|contentbody =<big><b>
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<br><br>
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<categorytree mode=pages>Teeth - Pathology</categorytree>
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==Introduction==
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</b></big>
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|logo =path-logo.png
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See [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|anatomy and physiology of the teeth]]
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==Functional Anatomy==
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[[File:Toothinfection.gif|200px]]
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*The [[Cavity & Gingiva - Pathology|gingival crevice]] is an important site for disease processes in mouth to begin.
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*In ruminants and rodents [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] may fail to oppose properly or to allow side to side movement of jaws. This produces uneven wear (especially in horse). Sharp edges are produced on the outside of the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] in the upper jaw and inside of the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] in the lower jaw, which causes painful feeding and inanition (not eating).
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**Approximately 75% of wasting horses have dental abnormalities.
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*This is not a problem in carnivores as do they not use [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] for [[Mastication|mastication]].
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*If a [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] is lost the opposing [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] may become very long and stop mouth closing properly. 
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**Seen mostly in rodents - [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] may even penetrate through [[Lips - Anatomy & Physiology|lip]].
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==Defence Mechanisms==
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==Developmental Pathology==
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===[[Erythropoietic Porphyra]].===
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===[[Photosensitisation]]===
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===[[Abnormal Wear of Teeth]]===
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===[[Abnormal Numbers of Teeth]]===
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==Infection of teeth==
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===[[Dental caries]]===
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===[[Infundibular Impaction]]===
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===Direct infection of pulp cavity===
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*For example, a dog whose canine has been snapped off while biting stones etc. exposes [[Pulp - Anatomy & Physiology|pulp]].
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*Also possible that infection in [[Pulp - Anatomy & Physiology|pulp]] cavity originates from a circulating pyaemia producing pulpitis.
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===Gingival crevice inflammation===
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*Mostly in carnivores (also cats), may occur in horses. 
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*[[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|Gingival]] inflammation starts because of dental calculus (tartar) from diets high in minerals and diets consisting of soft rather than hard crunchy food.
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*Dental plaque becomes calcified and whole [[Crown - Anatomy & Physiology|crown]] may become covered in brown chalky material.
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*Calculus gives brittle dirty brown covering to [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]].
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*This may not affect [[Enamel - Anatomy & Physiology|enamel]] at all but may produce mild [[Cavity & Gingiva - Pathology|gingivitis]] round edge and the gum may start to recede.
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*This exposes more of [[Crown - Anatomy & Physiology|crown]], may reach level of [[Dentine - Anatomy & Physiology|dentine]] and infection may enter the alveolus and loosen ligaments holding [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]] in and ultimately the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]] will become loose and fall out.
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*Pyorrhoea is unusual in sheep but, nonetheless, periodontal disease with “broken mouth” is a major cause of culling of ageing ewes.
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===Alveolar Periostitis===
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*A more virulent infection into the alveolus produces alveolar periostitis.
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*Infection spreads from [[Pulp - Anatomy & Physiology|pulp]] or from gingivitis to produce the periostitis.
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*This may then break out of the alveolus into the bone causing [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]].
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**Seen in infection of carnassial teeth in dogs as chronic sinus discharging below eye. So called 'malar' abscess.
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*Only treated by removal of [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]].
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*Abscess may break through into maxillary sinus. If drained will get recovery.
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**Other maxillary cheek [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] can be involved in pyaemic infection with sinus formation.
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*Hard to evaluate on [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]], may produce fistula that also needs [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]] removal.
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==Granulomatous and pyogranulomatous Inflammation==
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===Mandibular Osteomyelitis===
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[[Image:Lumpyjaw1.gif|right|thumb|125px|<small><center>Lesion caused by Actinomyces Bovis(Courtesy of Alun Williams (RVC))</center></small>]]
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*"Lumpy jaw"
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====Clinical====
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*Seen mainly in cattle and exotics caused by ''[[Actinomyces bovis]]'' producing [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]] of mandible.
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*Mostly young animals.
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*Will not heal without treatment and jaw enlarges until animal cannot eat.
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====Pathogenesis====
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*Starts as alveolar periostitis of lower cheek [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]], due to ingestion of poor coarse roughage e.g. straw or hay with lots of thistles. 
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*Slowly enlarging [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] (occasionally [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilla]]) due to granulomatous inflammation producing much fibrous tissue.
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*No real pus formation but "'''sulphur granules'''" in middle of lesion.
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*Organism causes "'''pyogenic granuloma'''."
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*Can grow to enormous size (e.g. size of grapefruit) and whole of mandible is blown apart by multiple foci of infection.
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<small>Also see:[[Tongue - Pathology#Actinobacillosis|Actinobacillosis - "Wooden Tongue" (Courtesy of Alun Williams (RVC))</small>]]
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====Pathology====
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3 major features:
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#Inflammatory removal of bone. As cortex of bone is pushed out by central inflammation produces thinning of bone cortex with proliferation of new periosteal bone. The centre of the [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] is eroded forming a honeycomb-like bone. Eventually will erode through bone producing [[Granuloma|granulomatous]] lesion on bottom of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] and eventually eroding through skin.
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#Granuloma with micro abscess's in centre with greenish / yellow granules in middle of pus. These granules known as "sulphur bodies". Sulphur body is a colony of tangled mass of Actinomyces filaments. This is surrounded by [[Neutrophils - WikiBlood|neutrophils]] and [[Macrophages - WikiBlood|macrophages]] forming a pyogenic granuloma. 
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#Masses of fibrous tissue surround the granuloma and fill the spaces where bone has been destroyed.
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===Odontoclastic resorptive lesions===
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*Cats
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**Odontoclasts attack external and internal to the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]].
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**Initially start at the neck/cervical region and extend into [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]] [[Root - Anatomy & Physiology|root]] and also enter the [[Root - Anatomy & Physiology|root]] via the apical foramen (stage 3 lesions)
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**20%+ of cats have them
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**Different from caries – demineralization by bacteria fermenting CHO on the [[Enamel - Anatomy & Physiology|enamel]].
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**ORLs – only occur when odontoclasts resorb the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]]/bone
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***continues with remodeling of [[Alveolar bone - Anatomy & Physiology|alveolar bone]] until ankylosis
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*** fixation of [[Periodontal ligament - Anatomy & Physiology|periodontal ligament]] and [[Lamina dura - Anatomy & Physiology|lamina dura]] so that the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]] is permanently fixed to the bone.
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*Odontoclasts normally only active in young animals to resorb the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology#Temporary Tooth|deciduous teeth]] to make way for the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology#Permanent Tooth|permanent teeth]] – so represents abnormal activation in adults.
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*Can have inflammatory infiltrates into the resportive lesions
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==Eosinophilic Inflammation==
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==Necrotizing Inflammation==
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==Lymphocytic and plasmacytic Inflammation==
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==Proliferative Pathology==
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===Hyperplastic===
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====Focal fibrous hyperplasia<ref name="epulides1"> </ref>====
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*44% of cases.
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*Dense collagenous tissue, with ulceration/superficial inflammation
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*Dystrophic calcificaition within the fibrous connective tissue stroma (often highly cellular, with 'young stellate fibroblasts'
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*No odontogenic epithelium seen.
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*Occasional strands of surface epithelium growing down into the stroma.
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*Most of these were previously diagnosed as fibromatous or ossifying epulides.
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===Neoplastic===
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====Peripheral odontogenic fibroma<ref name="epulides1">J Comp. Path. 1992 (106),  169-182  The  Histological  Nature  of  Epulides  in  Dogs  F.  J.  M.  Verstraete*,  A.  J.  Ligthelmf  and  A.  WeberT. ... review of 154 oral 'epulis' from dogs reviewed with the current (at the time) human literature.</ref>====
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[[Image:epulis.gif|right|thumb|125px|<small><center>Canine Epulis (Courtesy of Alun Williams (RVC))</center></small>]]
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*aka: Fibromatous epulis of periodontal ligament origin
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*17% of cases.
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*Proliferation of fibrous tissue with variety of osteoid, [[Cementum - Anatomy & Physiology|cementum]] or [[Dentine - Anatomy & Physiology|dentine]]-like material.
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*Isolated strands or islands of odontogenic epithelium always present (ie: suggesting induction of connective tissue by the epithelial cells).
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*The stroma contains neoplastic fibroblasts, with varying cellularity.
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*The overlying epitheluim is normal.
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====Peripheral ameloblastoma<ref name="epulides1"> </ref>====
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[[Image:ameloblastoma.gif|right|thumb|125px|<small><center>Ameloblastoma (Courtesy of Alun Williams (RVC))</center></small>]]
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*aka: basal cell carcinoma, acanthomatous ameloblastoma, acanthomatous epulis
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*18% of cases.
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*Islands and sheets of mature odontogenic epithelium within a collagenous fibrous connective tissue stroma of low/moderate cellularity.
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*Each of the islands bounded by a row of tall columnnar cells.
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*These palisading cells exhibit polarisation away from the basement membrane and had cytoplasmic vacuolation.
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*Central cells had a basaloid appearance.
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*Often infiiltrating into the underlying bone.
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*Synonymous with basal cell carcinoma.
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====Central ameloblastoma<ref name="epulides1"> </ref>====
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*Different from peripheral ameloblastoma - cystic changes and follicular arrangement of ameloblasts and stellate reticulum cells, resembling the basic structure of the [[Tooth Anatomy - Anatomy & Physiology|enamel organ]].
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==Degenerative Pathology==
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===Odontodystrophy===
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*Damage to [[Ameloblasts - Anatomy & Physiology|ameloblasts]] (which form [[Enamel - Anatomy & Physiology|enamel]]) in utero upsets permanent incisor formation.
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*[[Enamel - Anatomy & Physiology|Enamel]] is marked by pits, lines etc.
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====In ruminants:====
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*Damage to [[Enamel - Anatomy & Physiology|enamel]] formation most often caused by fluoride poisoning. 
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*Seen in cattle grazing on pasture contaminated by cement works effluent.
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*Chalky mottling and yellow brown pitting of [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|tooth]].
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====In canines:====
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[[Image:enamal-hypoplasia.gif|right|thumb|125px|<small>Enamal Hypoplasia Following a CDV infection (Courtesy of Alun Williams (RVC))<center></center></small>]]
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Very severe systemic disease early in life / or in utero may result in severe discoloration or pitting of [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]] due to effect on [[Enamel - Anatomy & Physiology|enamel]] formation. (e.g. [[Paramyxoviridae#Canine Distemper Virus (CDV)|distemper in dog]])
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==Metabolic Pathology==
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==Nutritiona Pathology==
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==Traumatic Pathology==
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==Vascular Pathology==
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==References==
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<small>
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With thanks to Andrew Jefferies (Cambridge) and Alun Williams (RVC) for providing access to their lecture materials
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<references/>
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</small>
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==Learning Tools==
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[[Alimentary Flashcards - Pathology#Teeth Flashcards|Teeth Flashcards]]
   
[[Category:Oral_Cavity_and_Gingiva_-_Pathology]]
 
[[Category:Oral_Cavity_and_Gingiva_-_Pathology]]
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