S. R. Prabhu - Handbook of Oral Pathology and Oral Medicine

Dilaceration:No treatment for mild dilacerationIf symptomatic due to gross dilaceration, tooth requires surgical extraction

A group of inherited disorders caused by defects in the genes that encode enamel matrix proteins, resulting in defective structure of the enamel involving both dentitions

Global prevalence: 0.5%

Caused by mutations or altered expression in five genes:AMEL (amelogenin)ENAM (enamelin)MMP20 (matrix metalloproteinase‐20)KLK4 (kallikrein‐4)FAM83H. 6–16

Inheritance can be autosomal dominant, recessive or x‐linked

Three types of amelogenesis imperfecta have been identified – hypoplastic, hypocalcified and hypomaturation:Hypoplastic type:Enamel is of reduced thickness due to a defect in the formation of normal matrixEnamel is pitted, grooved, stained and thinEnamel is normally mineralized; hard and translucentRadiographically, the enamel contrasts normally from dentineHypocalcified type:Enamel matrix is normal in quantityEnamel calcification is defectiveEnamel is weak in structure and vulnerable to attritionTeeth become opaque, stained and rapidly wear down ( Figure 1.6)Radiographically, enamel is less radio‐opaque than dentineHypomaturation type:Enamel is normal in thickness, shows opaque brownish‐yellow patchesEnamel mimics fluorotic mottled enamel in appearanceEnamel is soft and vulnerable to attrition

Other features that may occur in any of the above types of amelogenesis imperfecta include:Delay in dental eruptionMicrodontiaDeviant crown and morphologyRoot resorptionShort rootsEnlarged pulp chamberPulp stonesDens in dente (dens invaginatus)Tooth agenesisCrowding of teeth Figure 1.6 Amelogenesis imperfecta (hypocalcified type); the enamel is stained and vulnerable to attrition(source: by kind permission of Professor Charles Dunlap, Kansas City, USA).

Dental fluorosis

Dentinogenesis imperfecta

Enamel hypoplasia

Trauma

Molar incisor hypomineralization

History including a detailed family history

Pedigree plotting (family health history tree)

Clinical examination

Radiography

Aesthetic treatment

Treatment for symptoms if present (e.g. tooth sensitivity)

A group of autosomal dominant genetic conditions characterized by abnormal dentin structure affecting both the primary and secondary dentitions

Incidence of 1 in 6000 to 1 in 8000

Mutations in dentin sialoprotein genes

Primary and permanent teeth are affected

Teeth appear amber, brown/blue, or opalescent brown ( Figure 1.7a)

Syndromic form, osteogenesis imperfecta: opalescent dentine, blue sclera and short stature

The crowns may appear bulbous ( Figure 1.7b)

Pulp chambers are often small or obliterated

The roots are often narrow with small or with obliterated root canals Figure 1.7 Dentinogenesis imperfecta. (a) Note tooth wear and opalescent crowns. (b) Radiograph shows bulbous crowns and cervical constriction of molars.(source: by kind permission of Professor Charles Dunlap, Kansas City, USA.)

Hypocalcified forms of amelogenesis imperfecta

Osteogenesis imperfecta

Congenital erythropoietic porphyria

Conditions leading to early tooth loss

Permanent teeth discolouration due to tetracyclines

Vitamin D‐dependent and vitamin D‐resistant rickets

Family history

Pedigree construction

Detailed clinical examination

Radiography

The aims of treatment are to remove sources of infection or pain, restore aesthetics and protect posterior teeth from wear

Preservation of occlusal face height, maintenance of function and aesthetic needs are priorities

For the primary dentition, stainless steel crowns are recommended

A rare inherited disorder of dentin formation characterized by either absent or short conical roots

Two types occur: radicular dentin dysplasia (type 1) and coronal dentin dysplasia (type 2)

Coronal dentin dysplasia is a severe form of dentinogenesis imperfecta

Type 1: 1 in 100 000

Type 2: 1 in 6000 to 1 in 8000

Defective dentin sialoprotein gene for both types

Radicular type (type 1):Diffusely affects both dentitions: severe manifestations in deciduous teethCoronal enamel and dentin are normalRadicular dentin is defective: short roots result in tooth mobility and premature tooth lossStrength of roots is reducedHypersensitive dentinLoss of pulpal vitalityAbsent root canalsBifurcation is close to the apex in molarsPeriapical pathology is common (seen as periapical radiolucency)

Coronal type (type 2):Primary and permanent teeth are affectedTeeth appear amber, brown/blue or opalescent brown

Coronal type:The crowns may appear bulbousPulp chambers are often small or obliteratedThe roots are often narrow with small or obliterated root canalsRoots may be absent ( Figure 1.8) Figure 1.8 Dentinal dysplasia radiograph showing absence of roots(source: by kind permission of Professor Charles Dunlap, Kansas City, USA).

Dentinogenesis imperfecta

Osteogenesis imperfecta

Conditions that cause premature loss of teeth

Family history

Clinical examination

Radiography

Symptomatic and preventive care and meticulous oral hygiene

A rare non‐hereditary dental anomaly involving enamel, dentin and cementum of both dentitions, but mostly the teeth of one quadrant

A rare disorder

Unknown

Probably alteration in vascular supply in the jaws around developing teeth

Female predilection (female to male ratio 1.7 : 1)

Both dentitions are involved

Mostly one but rarely two quadrants are involved

Age at diagnosis: 2–4 years for deciduous teeth and 7–11 years for permanent teeth

Maxillary predominance (ratio of maxillary to mandibular width 1.6 : 1)

Failure of tooth eruption is common

Erupted teeth exhibit small brown crowns

Pulp necrosis is common

Early tooth exfoliation

Thin enamel and dentin appear surrounding enlarged radiolucent pulp chamber (hence the name ghost tooth)

Pulp stones are occasionally detected on radiography