Developmental disturbances of teeth Dr. Saleem Shaikh

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

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

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

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

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

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

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)

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

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

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

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

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 -

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

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

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

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

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 0.7 -1.2 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

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

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

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

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 ).

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.

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

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

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

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

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

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

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