Amelogenesis Imperfecta (AI), dentinogenesis inperfecta (DI), and dentin dysplasia (DD) revisited: problems in classification

Resident: J. Hencler
Date: 02/05/2010

Article title: Amelogenesis Imperfecta (AI), dentinogenesis inperfecta (DI), and dentin dysplasia (DD) revisited: problems in classification
Author: C. J. Witkop Jr.
Journal: J Oral Pathol 1989: 17: 547-553

Major topic: AI, DI, DD

Type of Article: Review

Main Purpose:
Update classification and prevalence of AI and discuss problems with the classification of inherited dentin defects.

Discussion:

AI should is limited to those inherited, congenital defects that only affect enamel formation and not accompanied by morphogenic or metabolic defects in other body systems other than tooth form or eruption. AI classification based on clinical exam is problematic b/c the same clinical features may have several modes of inheritance. The expression of AI can vary greatly from very mild forms to severe. AI prevalence differed in many studies at the time of this publication so was still debated. Now the estimated incidence of AI includes 1 in 14000, 1 in 8000, and 1 in 4000. 14 subgrps of AI with multiple inheritance patterns are known which complicates diagnosis. The 4 categories of AI are described according to the stage of tooth development in which each is thought to occur.

DI is an inheritable dental defect of pre-dentin matrix that results in amorphic, disorganized, and atubular circumpulpal dentin. DI is classified into 3 types. Type 1 occurs with osteogenesis imperfect (OI), Type 2 is also known as hereditary opalescent dentin. Type 3 is a rare type found only in a tri-racial isolated grp in Maryland called the Brandywine population and is proposed to be a different expression of the same type 2 gene.

DD represents a grp of inherited dentin disorders resulting in defects involving circumpulal dentin and root morphology. 2 Types are described. Type 1 has normal primary and perm crown morph but with amber translucency. Roots are short and sharply constricted. Primary teeth have obliterated pulps and both dentitions exhibit multiple radiolucencies and absent pulp chambers. Type 2 involves amber colored primary teeth closely resembling DI types 1 and 2. Perm teeth appear normal, but radiographically show thistle tube shaped pulp chambers with pulp stones. DD type 2 has been argued to be a type of DI on the basis of clinical, radiographic, histologic, and alterated structural protein similarities.

Assessment of article:
Awful, it was hard to understand and written in way too much genetic detail. Unless you enjoy an article that debates numerous intricate genetic differences that determine a complicated classification system, this article may not be for you. The article did do a good job going into each subtype of AI but lacked info on DI and DD.