1. Developmental disturbances of teeth
Dr. Saleem Shaikh

2. DEVELOPMENTAL DISTURBANCES IN STRUCTURE OF TEETH
Enamel hypoplasia
Dentinogenesis imperfecta
Dentin dysplasia
Regional odontogenic dysplasia

3. ENAMEL HYPOPLASIA
Defect of enamel due to disturbance during its formative process
Ameloblasts are among the most sensitive cells in the body
During the formative stages of enamel the ameloblast cells are susceptible to various factors which can disturb the process and the effect of which are reflected on the surface enamel after the eruption of tooth

4. Types Enamel hypoplasia Hereditary (Amelogenesis Imperfecta)
Based on causative factors:
Enamel hypoplasia
Hereditary
(Amelogenesis Imperfecta)
Environmental
Generalized
Focal
(Turners hypoplasia)

5. Differences between hereditary & environmental enamel hypoplasia
Both dentition affected
Only enamel is affected
Affected tooth shows diffuse or vertical orientation of defects
Environmental
Either one dentition affected
Affects enamel and other calcified structures
Affected tooth shows defect which is horizontally arranged

6. Hereditary enamel hypoplasia Amelogenesis imperfecta
Hereditary enamel dysplasia; Hereditary brown enamel; Hereditary brown opalescent tooth
It is a heterogenous group of hereditary disorders of enamel formation
Entirely an ectodermal disturbance.
The condition involves only the enamel while dentin, cementum & pulp remain normal
3 types
Hypoplastic type - Defective matrix deposition
Hypocalcification type – Defective calcification
Hypomaturation type- Defective maturation

7. Classification 1. Hypoplastic type
Generalized Pitted, autosomal dominant
Localized Pitted, autosomal dominant
Localized Pitted, autosomal recessive
Diffuse Smooth, autosomal dominant
Diffuse Smooth, X-linked dominant
Diffuse Rough, autosomal dominant
Enamel agenesis autosomal recessive
2. Hypomaturation type
Diffuse pigmented, autosomal recessive
Diffuse, X-linked recessive
Snow capped, X-linked
Snow capped, autosomal dominant
3. Hypocalcification type
Diffuse,Autosomal dominant
Diffuse,Autosomal recessive

8. Hypoplastic type The disease affects the stage of matrix formation
Teeth exhibit complete absence of enamel or there may be presence of enamel on some focal areas
Enamel thickness is usually below normal
Quantity is affected, but quality of formed enamel is normal
Tooth appears as though prepared for receiving a prosthetic crown
Radiographic features -
Enamel may appear totally absent or as a thin line
Radiodensity of affected enamel is similar to that of normal enamel (greater than dentin)

9. Hypocalcification type
The disease affects the stage of early mineralization
Enamel is of normal thickness(quantity not affected)
Tooth is normal in shape on eruption, but the enamel is lost very easily
Enamel is soft & can be easily removed with a blunt instrument
Enamel is yellowish brown on eruption
Radiodensity of affected enamel is lesser than that of normal enamel and is equivalent to normal dentin

10. Hypomaturation type The disease affects the stage of maturation
Enamel is of normal thickness (quantity not affected)
Teeth are normal in shape but enamel is opaque white or brownish in colour
Enamel does not have normal hardness & translucency and tend to chip off easily
It Can be pierced with an explorer tip with firm pressure
Snow capped teeth - It is the mildest form of hypomaturation type of amelogenesis imperfecta.
The enamel is of near normal hardness & has a zone of white opaque enamel on the incisal or occlusal one quarter to one third of crown.
Demonstrates an anterior to posterior distribution and have been compared to a denture dipped in white paint
Radiodensity of affected enamel is much lesser than that of normal enamel

13. Environmental enamel hypoplasia
FOCAL ENAMEL HYPOPLASIA; Also known as Turner’s hypoplasia;
Most common form of enamel hypoplasia
Occurs due to trauma or infection to deciduous teeth
Usually affects single tooth & is called as Turners tooth
Hypoplasia ranges from a mild, brownish discolouration to a severe pitting of enamel surface on the labial aspect
Frequently involved teeth are permanent maxillary/mandibular bicuspids & maxillary incisors
Severity of hypoplasia depends on severity of infection, degree of tissue involvement and stage of tooth formation

14. Pathogenesis Trauma Periapical Infection Deciduous teeth
Affect the ameloblastic layer
of permanent tooth
Disturb the enamel formation
Enamel defects

16. Generalized Enamel Hypoplasia
The ameloblasts in the developing tooth germ are sensitive to external stimuli
Any systemic or environmental disturbance can result in abnormalities in enamel formation which manifests as defects on the surface of tooth
It affects numerous teeth which are being formed at the time of disturbance
Clinically the defects can manifests as
1. Hypoplasia
2. Diffuse opacities
3. Demarcated opacities
Most often it manifests as a horizontal line of enamel hypoplasia with pits & grooves
CHRONOLOGIC HYPOPLASIA -

17. The line on the tooth surface indicates the zone of enamel hypoplasia
The location of the line corresponds with the developmental stage of affected tooth & width indicates the duration of the disturbances

18. Causes Prenatal Infections (Rubella, Syphilis)
Malnutrition, Metabolic & Neurological disorders during pregnancy
Chromosomal abnormalities
Excess chemical intake (Tetracycline, Fluoride)
Neonatal
Birth injury
Premature delivery
Prolonged labor
Low birth weight
Postnatal
Severe childhood infections (Viral exanthematous fever)
Congenital heart diseases
Nutritional deficiencies (Vit-B, Vit-D)
Endocrinal disorders

19. Enamel hypoplasia due to nutritional deficiency and exanthematous fevers
Serious nutritional deficiency is potentially capable of producing enamel hypoplasia
The teeth that form within the first year after birth are affected.
Teeth most frequently affected are central & lateral incisors, cuspids and first molars.
Premolars, 2nd & 3rd molars are rarely affected, since their formation does not begin until the age of 3 or later
Presents as pitting of the tooth surface

20. Enamel hypoplasia due to congenital syphilis
Hypoplasia is not of pitted variety
Involves the permanent maxillary & mandibular incisors and 1st molars
Anterior teeth are referred to as Hutchinson’s incisors and posterior teeth are referred to as mulberry molars.
Characteristically, the upper central is screw driver shaped, the mesial and distal surfaces tapering and converging towards the incisal edge.
Incisal edge is usually notched.
Middle lobe of tooth is affected
The crowns of first molars are irregular & constricted, and the enamel of the occlusal surface and occlusal third of tooth appears to be arranged in an agglomerate mass of globules rather that well formed cusps.
Resembles a mulberry, hence the name mulberry molars

22. Enamel hypoplasia due to fluoride
Excess amounts of fluoride can result in enamel defect known as dental fluorosis./ mottled enamel
The severity increases with an increase in amount of fluoride in the water.
The optimum range of fluoride in drinking water is ppm
Increased levels of fluoride interferes with calcification process of the enamel matrix leading to the formation of hypomineralized enamel
These alterations results in an increased surface and subsurface porosity of the enamel which alters the light reflection and creates the appearance of white chalky areas which later gets stained

24. Clinical features Affected teeth are caries resistant
Wide range of manifestations depending on fluoride levels
Grading
Questionable changes
White flecking or spotting of enamel
Mild changes
White opaque areas involving more of tooth surface areas
Moderate and severe changes
Pitting and brownish staining of surface
Corroded appearance
Mild cases- Bleaching of teeth
Severe cases- Prosthetic crowns

25. Dentinogenesis Imperfecta
A hereditary defect of dentin in the absence of any systemic disorder, consisting of opalescent teeth composed of irregularly formed and undermineralized dentin that obliterates the coronal and root pulpal chambers.
Also known as “Hereditary opalescent dentin”, “Capdepont’s teeth”
Severely affects the deciduous teeth than permanent teeth (Incisors & 1st molars; Least involved teeth- 2nd & 3rd molars)
Teeth exhibits a gray to brownish violet or yellowish brown appearance
Involved teeth exhibits a characteristic unusual translucent or opalescent hue.
Enamel is normal but fractures and chips away easily leads to exposed dentin and functional attrition presumably because of defective DEJ
Teeth are not particularly sensitive & are not caries prone

26. Associated with osteogenesis imperfecta, blue sclera
Type I
Associated with osteogenesis imperfecta, blue sclera    
 Type II
Not associated with osteogenesis imperfecta unless by
chance 
This type is most frequently referred to as Hereditary
opalescent dentin
Most common type   
Type III
Brandywine type, racial isolate in Maryland state
Same clinical presentation of Type I or II with multiple
pulpal exposures in deciduous dentition

27. Classification (Shafer)
DENTINOGENESIS IMPERFECTA 1: Dentinogenesis imperfecta without osteogenesis imperfecta (opalescent dentin), this corresponds to dentinogenesis imperfecta type II of Shields classification.
DENTINOGENESIS IMPERFECTA 2: Brandywine type dentinogenesis imperfecta: this corresponds to dentinogenesis imperfecta type III of Shields classification.
There is no substitute in the present classification for the category designated as DI Type I of the previous classification (Shield’s ).

29. Radiological features
Exhibit bulb-shaped or bell shaped crowns with constricted CEJ (tulip shaped)
Thin & blunted roots
Early obliteration of root canals and pulp chamber
Cementum, PDL & bone appears normal
Type II exhibits great variability in deciduous teeth, ranging from normal to those changes of type I
Shell teeth
Apparently normal enamel
Extremely thin dentin (may involve entire tooth or isolated to the root)
Enormous pulp chambers (not as a result of resorption, but due to insufficient dentin)
Appear as shells of enamel & dentin surrounding enormous pulp chambers and root canals.

31. Histopathological features
Enamel & mantle dentin are normal
Remaining dentin is severely dysplastic & exhibits vast areas of inter- globular dentin
Dentinal tubules are short, disoriented, irregular & widely spaced
Scanty odontoblasts line the pulp and they can be seen in the defective dentin
Smooth DEJ
Treatment is aimed at preventing excessive tooth attrition & improving esthetics
Metal / Ceramic crowns & over dentures can be given

32. Dentin dysplasia
A hereditary defect characterized by defective dentin formation & abnormal pulpal morphology
Autosomal dominant disorder
Type I – Radicular dentin dysplasia
Also known as “Rootless teeth”
Type II – Coronal dentin dysplasia
Mild
Severe

33. Clinical features Type I Type II
Disturbance in development of radicular dentin
Disturbance in development of coronal dentin
Normal crowns both structurally & morphologically
Semi-transparent opalescent primary teeth           
Normal appearance in the permanent teeth
Color of teeth normal with slight bluish translucency in cervical region
Amber – grey color
Early loss of dentin organization results in extremely short roots
Later disorganization results in minimal root changes
Affected teeth exhibits short roots, delayed eruption , severe mobility & premature exfoliation

35. Radiological features
Type I
Type II
Permanent teeth: Features vary on the proportion of organized versus disorganized dentin
Early disorganization - extremely short roots with little or no pulp
Somewhat Later disorganization - crescent or chevron shaped pulp chambers overlying shortened roots that exhibit no pulp canals
Late disorganization – normal pulp chamber with large pup stone
Permanent teeth: Exhibits abnormally large pulp chambers and apical extension described as flame shaped or thistle-tube in shape. Pulp stones present
Deciduous teeth affected severely with little or no detectable pulp
Deciduous teeth shows bulbous crowns, cervical constriction and early obliteration of pulp (Resembles DI)
Periapical radiolucencies around the defective roots
Absence of periapical radiolucencies

37. Histopathological features
Type I
Type II
Normal enamel
Normal enamel and radicular dentin with partial obliteration of root canals
Portion of coronal dentin is usually normal and may show tubular dentin apical to it
Pulp is obliterated by calcified tubular dentin, osteodentin & fused denticles
Near normal coronal dentin with numerous areas of interglobular dentin near the pulp
Normal dentinal tubule formation appears to be blocked so that new dentin forms around obstacles and takes on characteristic appearance described as lava / stream flowing around boulders
Abnormally large pulp chambers with pulp stones

39. Regional Odontodysplasia
It is a uncommon non-hereditary developmental disturbances of tooth characterized by defective formation of enamel & dentin with abnormal calcifications of pulp & follicle
Also known as “Ghost teeth”
Cause
- Local ischemic change during odontogenesis
Clinical features:
More common in permanent dentition
More common in maxilla
Affects several teeth in a single quadrant
Maxillary anterior teeth affected more
Failure of eruption or delayed eruption of affected teeth
Teeth are deformed, yellowish – brown in color with a soft leathery surface

40. Radiological features
Marked decrease in radio density of teeth
Enamel & dentin are very thin & radiological distinction not possible
Extremely large & open pulp chamber with pulp stones
Ghostly appearance of affected teeth
Abnormal enamel & dentin
Large pulp chamber with pulp stones
Calcification in follicular connective