Dental Anomalies Part II

Question 1

what is amelogenesis imperfecta

Answer 1

• inherited genetic mutation
• isolate or syndromicc
• enamel is affected in all or nearly all teeth

Question 2

what dentition is affected in amelogenesis imperfecta

Answer 2

primary and permanent

Question 3

what is type 1 alemogenesis imperfecta

Answer 3

hypoplastic type: thinner but hard enamel

Question 4

what is type 2 amelogenesis imperfecta

Answer 4

hypomaturation type: relatively hard but colored (not translucent)

Question 5

what is type III amelogenesis imperfecta

Answer 5

hypomineralized or hypocalcified: softer rough colored undermineralized enamel

Question 6

what is type IV amelogenesis imperfecta

Answer 6

hypoplastic- hypomature with taurodontism

Question 7

describe the type 1 hypoplastic type amelogenesis imperfecta

Answer 7

• thin bur mineralized enamel. looks radiopaque
• quantitative enamel defect: failure during enamel matrix secretory stage (enamel agenesia is rare)
• generalized or localized, pits, striae, groove defects
• diffuse smooth or rough
• teeth appear white to yellow-brown, small, and square shaped
• open contacts “picket fence” appearance. flat occlusal surface, low cusps
• delayed eruption and increased impaction

Question 8

describe type II amelogenesis imperfecta

Answer 8

• normal thickness of enamel. a qualitative defect
• soft enamel - as radiodense as dentin
• less translucid enamel: cloudy white, yellow or brown color
• hard and protective

Question 9

describe type III amelogenesis imperfecta

Answer 9

• enamel of normal thickness but soft, porous and shedding easily from the dentin. normal shape at eruption
• these teeth are very sensitive even to physical contact with a toothbrush
• soft enamel that is less dense than dentin in radiographs
• grossly worn teeth to gingival level
• the color of enamel can range from white to creamy yellow-brown

Question 10

describe dentinogenesis imperfecta

Answer 10

• primary dentition more severely affected
• amberlike translucency (yellow to blue-gray)
• enamel separates easily from dentin (faulty DEJ)
• accelerated attrition -> anterior open bite
• cervical constriction -> bulbous crown
• short and slender roots
• partial or complete obliteration of pulp chambers and canals
• types I, II and III

Question 11

describe type I dentinogenesis imperfecta

Answer 11

• associated with osteogenesis imperfecta
• mutation in collagen synthesis genes

Question 12

describe type II dentinogenesis imperfecta

Answer 12

• no skeletal defects
• enlarged pulp chambers in primary teeth (occasional)d

Question 13

describe type III dentinogenesis imperfecta

Answer 13

• brandywine isolate
• found in people originating from southern maryland
• enlarged pulp chambers
• pulp exposure

Question 14

what are the acquired abnormalities

Answer 14

• attrition
• abrasion
• erosion
• third molar impaction

Question 15

what is attrition

Answer 15

physiologic wear of teeth

Question 16

what is abrasion

Answer 16

mechanical wear of teeth

Question 17

what is erosion

Answer 17

chemical wear of teeth

Question 18

what are the ways third molars can be impacted

Answer 18

full impaction and partial impaction

Question 19

what are the orientations for third molar impactions

Answer 19

• vertical
• inverted
• mesioangular
• distoangular
• horizontal
• inverted mesioangular
• inverted distoangular