List 4 types of environmental alterations of teeth.

-Developmental tooth defects

-Postdevelopmental structure loss

-Discoloration of teeth

-Localized disturbances in eruption

Visible Enamel Defects

(1)  List 3 types

(2)  Explain prevalence

(1) 

• Hypoplasia
• pits, grooves, or larger areas of missing enamel.
• Diffuse Opacities
• normal thickness but variations of translucency.
• Demarcated Opacities
• normal thickness, but areas of increased opacity w/ sharp demarcation from adjacent enamel.

(2)

• Extremely common - possibly over 68% permanent dentition involved in children.
• Avg of 3.6 teeth involved.
• 67.2% opacities
• 14.6% hypoplasia
• 13.4% both patterns

• Birth-related trauma
• Chemicals
• Chromosomal abnormalities
• Infections
• Inherited diseases
• Malnutrition
• Metabolic disorders
• Neurologic disorders

• Local acute mechanical trauma
• Electric burn
• Irridiation
• Local infection

• Turner's hypoplasia
• Molar incisor hypomineralization
• Hypoplasia caused by antineoplastic therapy
• Dental fluorosis
• Syphilitic hypoplasia

(1)  Seen in succedaneous teeth - most commonly bicuspids.

(2) 

• Due to periapical infection of deciduous tooth.
• May also see defects due to direct trauma.
• Displacement of deciduous tooth may cause damage to the underlying tooth bud.
• May cause severe alteration of tooth shape (dilaceration).

(3)  Timing, severity.

(1)  Molar-incisor hypomineralization is defined as a hypomineralization of systemic origin.

Affects one to all of the first permanent molars and is often associated with affected permanent incisors.

(2)  Primary teeth are not affected.

(3)  White/yellow/brown opacities.

(4)  Well demarcated compared to normal enamel.

Molar Incisor Hypomineralization

(1) Tooth surfaces affected

(2)  Symmetrics

(3)  What increases the risk of defects to the incisors appears to increase when...

(4)  Symptoms

(1)  Usually presents on the buccal or occlusal surfaces of the molars and incisors.

(2)  Asymmetrical defects.

(3)  ....more first permanent molars have been affected.

(4)  The affected molars are sensitive to cold and appear to be more difficult to anesthetise.

Molar Incisor Hypomineralization

(1)  The lesions on the incisors are usually not as _____ as those in the molars and present mainly a _____.

(2)  What about the remaining permanent dentition?

(1)  extensive, cosmetic problem.

(2)  Remaining permanent dentition is usually not affected.

Hypoplasia due to antineoplastic therapy

(1)  Avg age.

(2)  Consequences of odontogenesis is very sensitive to radiation.

(3)  Effects of chemotherapy.

(1)  Most common under 12 years of age and most severe under 5 years of age.

(2)  Hypodontia, microdontia, radicular & enamel hypoplasia.

(3)  Chemotherapy can produce similar changes but they are less severe than those seen with radiation.

Dental Fluorosis

(1)  Definition

(2)  Symmetry

(3)  Critical period of development is......

(1)  Permanent bypomaturation of enamel causes surface and subsurface porosity of enamel.

(2)  Should appear as bilateral and symmetric distribution of lusterless, white, opaque areas of enamel.

(3)....second and their eyars of life when the incisors are undergoing enamel maturation.

Dental Fluorosis

(1)  Major concerns are ______.

(2)  Severity is _____ related during _______.

(3)  True enamel hypoplasia is common/uncommon.

(4)  Used to be that fluorosis was mostly due to ______

(1)  aesthetic.

(2)  dose, critical tooth development times.

(3)  uncommon.

(4)  naturally fluoridated water.

Syphilitic Hypoplasia

(1)  Seen in ______.

(2)  Describe Hutchinson's incisors.

(3)  Describe Mulberry molars.

(1)  congenital syphilis.  very rare now.

(2)  constricted incisal edge gives incisor teeth a "screwdriver" appearance.  may see an incisal notch.

(3)  constricted occlusal table.  bumpy occlusal surface, like "mulberries."

List Postdevelopmental loss of tooth structure

• Tooth wear
• Attrition
• Abrasion
• Erosion
• Abfraction

• Internal and external resorption

(1)  Define attrition

(2)  Define abrasion

(3)  Define erosion

(4)  Define demastication

(5)  Define perimolysis

(1)  Loss of tooth structure due to "tooth to tooth" contact during occlusion and mastication.

(2)  Pathologic loss of tooth structure due to mechanical action of an external agent.

(3)  When loss of tooth structure is due to chemical action not caused by bacteria.

(4)  When tooth wear is accelerated by chewing an abrasive substance.

(5)  When erosion is caused by dental exposure to gastric secretions.

(1)  Define abfraction

(2)  Abfraction is predominately seen where?

(3)  Proposed etiology of abfraction.

(1)  Controversial lesions that present as wedge-shaped defects in the cervical areas of teeth.

(2)  On the facial surfaces of bicuspids and molars.

(3)  Proponents of the diagnosis suggest that it is due to weakening of the dentin due to flexure secondary to bruxing.