Chapter 2: Abnormalities of teeth Flashcards
Environmental effects on tooth structure development
-‐ Enamel hypoplasia: pits, grooves and larger areas of missing enamel
-‐ Diffuse opacities: increased white opacity with no clear boundaries from normal enamel
-‐ Demarcated opacities: increased opacity with clear boundaries
-‐ Exanthematous fevers: Ant teeth and 1st molars with horizontal rows of pits or enamel.
-‐ Turner’s hypoplasia: due to periapical inflammation or trauma of overlying deciduous
-‐ Molar-‐incisor hypomineralization: affects molars (“cheese molars”)
-‐ Radiotherapy: hypodontia, microdontia, enamel/radicular/MD hypoplasia
-‐ Fluorosis: white, chalky, hypomature enamel or mottled enamel (stained yellow/brown)
-‐ Amoxicilin use: ~ fluorosis. Affects 1st molars and MX central incisors.
Postdevelopmental loss of tooth structure
-‐ Attrition: loss caused by tooth/tooth contact (eg. bruxism)
-‐ Abrasion: caused by mechanical external agent (eg. toothbrush-‐ horizontal cervical notches).
-‐ Demastication: chewing of an abrasive substance (attrition+abrasion)
-‐ Erosion: caused by nonbacterial chemical agent (eg. acidity from soft drinks). Classic pattern is cupped lesion (central depression of dentin rounded by elevated enamel).
-‐ Abfraction: caused by occlusal stresses at a location away from the wear. V-‐shaped on cervical.
-‐ Perimolysis: erosion of teeth due to gastric secretions
-‐ Noncarious cervical lesion: focal facial tooth wear at gingival due to erosion and/or attrition
-‐ Tooth resorption: internal (by dental pulp cells) or external (by PDL cells; more common)
-‐ Factors assoc w/ external resportion: zoster, Paget’s disease, cysts and tumors
-‐ Inflammatory internal resorption: dentin replaced by granulation tissue
-‐ Pink tooth of Mummery: inflammatory internal resorption affecting coronal pulp
-‐ Replacement/metaplastic internal resorption: dentin replaced by bone. Area is radiodense.
-‐ External resorption: moth-‐eaten RL (usually apical). Due to effects of dentinoclasts.
-‐ Invasive cervical resorption: rapid external resorption starting at cervical region
-‐ Multiple idiopathic apical root resorption: affects multiple teeth without obvious cause
Environmental discoloration of teeth
-‐ Gingival hemorrhage: green from breakdown of hemoglobin into biliverdin (~ bacterial)
-‐ Stannous fluoride: labial surfaces of anterior teeth and occlusal of posterior teeth
-‐ Chlorhexidine: interproximal surfaces near gingival margins (Listerine and sanguinaria too)
-‐ Gunther disease (congenital erythropoietic porphyria): depositin of porphyrin. Red teeth
-‐ Ochronosis: blue/black discoloration, connective tissue, tendons, cartilage. Seen in alkaptonuria (black urine disease: AR disorder of phenylalanine and tyrosine metabolism).
-‐ Chlorodontia: green teeth in hyperbilirubinemia, due to biliverdin deposition.
-‐ Pink teeth: trauma, inflammatory internal resorption, leprosy (MX incisors) and postmortem
-‐ Tetracycline: becomes incorporated into developing tooth. Bright yellow to dark-‐brown teeth.
-‐ UV light diagnostic for tetracycline discoloration (shows yellow fluorescence)
-‐ Minocycline: blue-‐gray discoloration of the alveolus that is evident through the thin mucosa
Localized disturbances in eruption
-‐ Impacted tooth: tooth that ceases to erupt before emergence
-‐ Unerupted teeth: impacted (physical barrier) or embedded (lack of force)
-‐ Eruption sequestrum: bone spicule overlying crown of a partially erupted tooth
-‐ Ankylosis: cessation of eruption after emergence due to fusion of tooth with bone. Aka secondary retention. Most common in MD primary first molars.
Developmental alterations in the number of teeth
-‐ Anodontia: total lack of teeth (usually hypohydrotic ectodermal dysplasia)
-‐ Hypondontia: lack of 1+ teeth; oligodontia: lack 6+ teeth
-‐ Hypodontia: PAX9 (molars), MSX1 (distal tooth of each type) and He-‐Zhao deficiency (China).
-‐ AXIN2 hypodontia: assoc with colonic polyps and colorectal ca.
-‐ Mesiodens: supernumerary tooth on anterior maxilla
-‐ Distodens (distomolar): fourth molar
-‐ Paramolar: ST located lingually or bucally to a molar
-‐ ST: supplemental (normal size/shape) or rudimentary (abnormal size/shape).
-‐ Rudimentary: conical, tuberculate and molariform
-‐ Dental transposition: normal tooth in abnormal location. Usually canines and first premolars
-‐ Natal teeth: present at birth or shortly after. Assoc with Riga-‐Fede disease.
Developmental alterations in the size of teeth
-‐ Microdontia associated with hypodontia; macrodontia assoc with hyperdontia
-‐ Relative microdontia: teeth are normal, but jaws are larger (macrognathia)
-‐ Diffuse microdontia: seen in Down syndrome and pituitary dwarfism
-‐ Relative macrodontia: teeth normal, jaw smaller (micrognathia)
-‐ Diffuse macrodontia: gigantism, otodental syndrome, XYY males and pineal hyperplasia.
-‐ Otodental syndrome: globe shaped molars and deafness
-‐ Unilateral macrodontia: hemifacial hyperplasia
Developmental alterations in the shape of teeth
-‐ Gemination: single enlarged tooth; tooth count normal if anomalous is counted as one
-‐ Fusion: single enlarged tooth; tooth count missing one if anomalous is counted as one
-‐ Concrescence: union of teeth by cementum only (developmental or post-‐inflammatory)
-‐ Accessory cusps: cusp of carabelli, talon cusp, dens evaginatus
-‐ Cusp of carabelli: on palatal surface of mesiolingual cusp of MX 1st molar
-‐ Protostylid: accessory cusp on mesiobuccal of MD molar
-‐ Talon cusp: located on lingual ant teeth (MX lat incisor). Assoc w/ Rubinstein-‐Taybi syndrome
-‐ Rubinstein-‐Taybi syndrome: talon cusps, mental retardation, broad thumbs and toes
-‐ Dens evaginatus: cusplike elevation in occlsal of PM and molars. 25% lead to pulpal pathosis.
-‐ Shovel-‐shaped incisors: lingual surface ~ scoop of a shovel (100% of inuits/Indians; 15% asians)
-‐ Dens invaginatus: Deep surface invagination of crown/root lined by enamel (most MX lat incisor)
-‐ Dens in dente: large invagination in DI resembling “tooth within a tooth”
-‐ Dilated odontome: dilated invagination in DI disturbing tooth development
-‐ Ectopic enamel: enamel pearl (root) and cervical enamel extension (CEJ of molars bifurcation)
-‐ Taurodontism: enlargement of the body and pulp chamber (rectangular teeth)
-‐ Classification: mild (hypotaurodontism), moderate (meso) and severe (hypertaurodontism)
-‐ Taurodontism increased in pts with hypodontia, cleft lip and cleft palate. Assoc w/ ectodermal dysplasia, hypophosphatasia, Down and Tricho-‐dento-‐osseous syndromes
-‐ Hypercementosis vs cementoblastoma: the latter has pain, expansion and continuous growth
-‐ Generalized hypercementosis strongly associated with Paget’s disease of bone
-‐ Dilaceration: abnormal angulation or bend in the root. Idiopathic, trauma or adjc lesion
-‐ Supernumerary roots: increased # of roots. Most molars and PM.
Amelogenesis imperfecta
-‐ Group of conditions with altered enamel in absence of systemic disorder
-‐ AMELX9 (amelogenin), ENAM (enamelin), MMP-‐20 (enamelysin), KLK4 (kallikrein), DLX3 (group of genes) and AMBN (ameloblastin) gene mutations identified
-‐ Hypoplastic: Inadequate deposition of enamel matrix (generalized pitted, localized pitted, AD diffuse smooth, x-‐linked diffuse smooth, diffuse rough, enamel agenesis). All teeth present and erupted, but covered by very thin layer of discernable enamel
-‐ Hypomaturation: Defect of maturation of crystal structure (diffuse pigmented, x-‐linked, snow capped). Teeth have normal shape, but discolored. Enamel softer than normal.
-‐ Hypocalcified (diffuse): lack of mineralization. Normal tooth shape, but soft and very dark.
-‐ AI with taurodontism: hypomaturation-‐hypoplastic (IVA; thicker enamel) and hypoplastic-‐ hypomaturation (IVB)
-‐ Tricho-‐dento-‐osseous syndrome: AI+taurodontism, kinky hair, osteosclerosis, brittle nails
Dentinogenesis imperfecta (hereditary opaslescent teeth, Capdepont’s teeth)
-‐ Alteration of dentin w/o systemic disorder (osteogenesis imperfecta with opalascent teeth is a different disorder). DI has DSPP gene mutation; OI COL1A1 or COL1A2 gene mutation
-‐ Teeth have blue-‐to-‐brown discoloration, with translucence (opalescent teeth)
-‐ Xray: bulbous crowns, cervical constriction, thin roots and obliteration of canals and chambers
-‐ Shell teeth: normal thickness enamel, thin dentin and very enlarged pulp
-‐ Histo: short tubules in granular dentin with calcifications
Dentin dysplasia
-‐ No correlation with systemic disorders or dentinogenesis imperfecta
-‐ Type I (radicular DD): Types Ia-‐Id. Rootless teeth, no pulp, periapical RL, pulp stones
-‐ Fibrous dysplasia of dentin: radiodensity fills pulp chamber and canal. Small foci of RL in pulp (dif from DI) and roots have normal length (dif from DD)
-‐ Type II (coronal DD): Normal root length. DSPP mutation. Deciduous same clinical features of DI. Permanent have normal color, but flame-‐shaped (thistle tube-‐shape) pulp and pulp stones.
-‐ Dentin-‐dysplasia like: calcinosis universalis, rheumatoid arthritis and vitaminosis D, sclerotic bone and skeletal anomalies and tumoral calcinosis
-‐ Pulpal dysplasia: Teeth normal clinically. Flame-‐shaped pulp and pulp stones in both dentitions
-‐ Histo: type 1-‐ whorls of tubular dentin with peripheral layer of normal dentin (stream flowing around boulders). Type 2-‐ deciduos same as DI. Permanent: atubular dentin, pulp stones
Regional odontodysplasia (ghost teeth)
-‐ Non-‐hereditary developmental anomaly of enamel, dentin and pulp.
-‐ Vascular (several cases assoc w/ vascular nevi), neural or growth abnormalities
-‐ Ghost teeth: extremely thin enamel and dentin surrounding an enlarged RL pulp
-‐ Histo: enameloid conglomerates (focal collections of basophilic calcifications; also seen in AI)
