Dental Anomalies PDF

-1- Developmental Disturbances of Teeth Classification: I. Abnormalities in Number: (defective initiation) A) Decrease in number 1. Total anodontia 2. Partial anodontia. B) Increase in number: hyperdontia 1. Pre-deciduous dentition....

-1- Developmental Disturbances of Teeth Classification: I. Abnormalities in Number: (defective initiation) A) Decrease in number 1. Total anodontia 2. Partial anodontia. B) Increase in number: hyperdontia 1. Pre-deciduous dentition. 3. Supernumerary teeth. 2. Post-permanent dentition. 4. supplemental teeth. II. Abnormalities in size (defective proliferation) 1. Microdontia. 2. Macrodontia. III. Abnormalities in shape ( morpho -differentiation). 1. Gemination. 2. Fusion. 3. Concrescence. 4. Dilaceration. 5. Talon cusp. 6. Taurodontism 7. Supernumerary root. 8. Enamel pearl 9. Dens Invaginatus. 10. Congenital syphilis IIII. Abnormalities in structure (defective apposition and calcification): A) Defects of Enamel: 1. Hereditary defects (amelogenesis imperfecta). 2. Acquired defects of enamel. B) Defects of Dentin: Dentinogenesis imperfecta. C) Defects of Enamel and Dentin: - Regional odontodysplasia. IV. Abnormalities in Eruption (defective eruption): A) Premature eruption. B) Delayed eruption. C) Embedded and impacted teeth. D) Submerged teeth.  -2- ABNORMALITIES IN THE NUMBER OF TEETH Variation in number of teeth may be either a decrease or an increase than normal. the permanent dentition is mostly affected, while the deciduous dentition is rarely involved. A) DECREASE IN THE NUMBER OF TEETH: HYPODONTIA -ANODONTIA Classification: 1. Total anodontia (absence of all teeth): a. Associated with hereditary ectodermal dysplasia. b. Unassociated with hereditary ectodermal dysplasia. 2. Partial anodontia or hypodontia: (absence of a single tooth or a group of teeth): 3. a. True anodontia, the absent teeth fail to develop. b. Pseudo anodontia, the clinically absent teeth develop but fail to erupt (embedded or impacted teeth). c. False anodontia, occurs as a result of tooth loss (extraction). TOTAL ANODONTIA Total absence of all teeth is exceedingly rare. It usually occurs in association with hereditary ectodermal dysplasia. Hereditary Ectodermal Dysplasia "Streeter's Syndrome" It is a hereditary defect in the development of the ectodermally derived structures. the disease affects mainly males Clinical Features: The skin is thin, smooth and dry. Total or partial absence of sweat glands results in the inability to regulate body temperature and the patient can not tolerate hot weather. Lack of sebaceous glands results in dry skin. The hair follicles may be defective or absent. Fingernails are usually defective  -3- Oral Manifestations: Total or partial anodontia of both dentitions. The few teeth that are present are often retarded in eruption and cone- shaped. The palate is frequently high and a cleft palate may be present. Salivary glands hypoplasia with xerostomia is sometimes seen. The alveolar process is deficient in height. PARTIAL ANODONTIA hypodontia Failure of development of one or more permanent teeth is a rather common condition. The most common congenitally absent permanent teeth are the third molars, followed by the maxillary lateral incisors and the mandibular second premolars, often bilaterally. Congenitally missing deciduous teeth are uncommon, but, when occurring, usually involve the maxillary lateral incisor. Etiology: Unknown. Hereditary tendency (familial). Hereditary ectodermal dysplasia. Radiation therapy of the face during tooth formation at an early age may result in the destruction of tooth germs Absence of upper lateral incisor may be associated with cleft palate. B) INCREASE IN NUMBER OF TEETH: ADDITIONAL TEETH Classification of Additional Teeth: 1. Predeciduous dentition. 2. Post-permanent dentition. 3. Supernumerary teeth.  -4- 4. Supplemental teeth. (1) Predeciduous dentition: It is a very rare condition and is due to accessory buds being given before the formation of the enamel organ of the deciduous teeth. They are rudimentary in size, present at birth usually erupted in the mandibular incisor area, and are weakly attached to the gum. Predeciduous teeth should be distinguished from prematurely erupted deciduous teeth which may have erupted at birth. (2) Post-permanent dentition: It is that dentition formed after the permanent dentition. Their enamel organ is presumed to arise from the dental lamina after giving the enamel organ of the permanent series. The majority of such cases are believed to arise from delayed eruption of previously embedded or impacted permanent teeth. (3) Supernumerary teeth: These are extra teeth that do not morphologically resemble any of the adjacent normal teeth. They are far more common in the maxilla than in the mandible and are found more often in the permanent dentition than in the primary dentition. They may be small and conical in shape, single or multiple, erupted or impacted, or inverted. Supernumerary teeth are classified according to their site of eruption into: - Mesiodens: located between the maxillary central incisors. - Distomolar: located distal to the third molar. - Paramolar: located on the buccal surface of upper molars. Etiology: - may have a hereditary tendency. - Multiple impacted supernumerary teeth may be associated with cleidocranial dysostosis Pathogenesis: - It may arise from additional tooth germ. - or division of the tooth germ of the normal series.  -5- Clinical consideration: - Additional teeth usually erupt in an abnormal position, labial or buccal to the arch, - Supernumerary tooth may prevent a normal tooth from erupting. - Impacted supernumerary teeth can develop dentigerous cysts around the crown. 4- Supplemental teeth : supplemental teeth …. morphologically resemble the adjoining teeth. Its most common sites are maxillary lateral incisors, lower premolar region, or distal to lower third molar. Cleidocranial Dysplasia It is a hereditary rare disease characterized by deficient growth of bones developed in the membranes as the cranial vault, maxilla, mandible, and clavicles Oral and Dental Clinical Manifestations: 1. high arched palate. 2. Delayed shedding of deciduous teeth 3. Delayed eruption of permanent teeth. 4. Presence of unerupted multiple supernumerary teeth. 5. The crown may be conical in shape. 6. Some teeth may show gemination. 7. enamel hypoplasia. 8. unerupted teeth have hooked roots. 9. Lack of cellular cementum. 10. Multiple dentigerous cysts may develop in relation to some of the unerupted teeth.  -6- ABNORMALITIES IN THE SIZE OF TEETH MICRODONTIA It means abnormal small teeth: Classification: 1. True. A: generalized microdontia. All the teeth in both arches are smaller than normal. True. B: localized microdontia involving a single or group of teeth: The most commonly affected single teeth are the maxillary lateral incisor "peg lateral" and third molar. 2. Relative generalized microdontia. Normal-sized teeth appear small in large jaws. MACRODONTIA It means abnormal large teeth: Classification: 1. True. A: generalized macrodontia. All teeth in both arches are larger than normal. True. Localized macrodotia involving single or group of teeth: The most commonly affected single tooth are maxillary central incisors, canines followed by maxillary lateral and third molars. 2. Relatively generalized macrodontia. Normal-sized teeth appear large in small jaws.  -7- Microdontia Macrodontia ABNORMALITIES IN THE SHAPE OF TEETH GEMINATION Gemination is characterized by the partial division of a single tooth germ, resulting in a tooth that exhibits two completely or incompletely separated crowns that have a single root and root canal. Gemination can affect the deciduous and permanent dentitions and is most common in the maxillary incisor region. The number of teeth is usually normal. FUSION Fusion results from the union of two adjacent tooth germs. The cause of fusion is uncertain – heredity, trauma, and crowding have all been suggested. Fusion can be complete or incomplete, depending on the stage of tooth development at the time of contact. Early contact with developing tooth germs can result in a fusion involving the entire length of the teeth; later contact can result in the union of roots only. The root canals are usually separated. The number of teeth is reduced by one, except in cases where one of the fused tooth germs was that of a supernumerary tooth. -fusion of the entire length of two teeth (enamel, dentin, and cementum) - fusion of the root only (dentin and cementum) CONCRESCENCE Concrescence is a type of fusion that occurs: After root formation is complete. The teeth are joined along their roots by cementum. Trauma or crowding of teeth can cause concrescence.  -8- DILACERATION Dilaceration is the presence of angulation or a sharp bend along the long axis of a tooth. The cause of this condition has been related to trauma during root development. The curve or bend may occur anywhere along the length of the tooth, sometimes at the cervical portions, at other times midway along the root or even just at the apex of the root, depending upon the amount of root formed when the injury occurred. If the crown developed and root not – trauma – bending of the crown bc it is the hard structure Concrescence Dilacerations TALON CUSP It is an extra cusp resembling an eagle's talon. It projects lingually from the cingulum area of a maxillary or mandibular permanent incisor and extends to the incisal edge. It is composed of normal enamel and dentin and contains a pulp horn.  -9- TAURODONTISM The term literally means "bull-like" teeth. It is a variation in tooth form in which there is: enlargement of the tooth trunk at the expense of the roots; the bifurcation or trifurcation is located apically. Pathogenesis: It is believed that the condition is due to the failure of Hertwig's epithelial root sheath to invaginate at the proper horizontal level to form the furcation area. Classification: mildest form extreme form, the bifurcation or trifurcation occurs near the apices of the roots Clinically: The teeth have no remarkable or unusual morphological clinical characteristics. Both the permanent and deciduous teeth may be affected. It may be unilateral or bilateral affecting a single tooth or a group of teeth, mostly molars. Radiographically: The pulp chamber is extremely large with a much greater apico-occlusal height than normal. The pulp lacks the usual cervical constriction. The bifurcation or trifurcation is apically displaced and the roots are exceedingly short.  - 10 - Talon cusp Taurodontism SUPERNUMERARY ROOTS Supernumerary or extra roots are most commonly seen in mandibular premolars, canines, and maxillary and mandibular third molars. Supernumerary roots are diagnosed radiographically. ENAMEL PEARL "Enameloma" Enamel pearl is a small, spherical enamel projection located on the root surface near the bifurcation or trifurcation area and is usually found on maxillary molars. Histologically; It may consist of enamel only or enamel, dentine, and pulp. Pathogenesis: It may occur as a result of the abnormal displacement of ameloblasts below the amelodentinal junction. Or due to differentiation of cells of the epithelial root sheath of Hertwig into ameloblasts during root formation so that, a nodule of enamel forms in place of cementum. DENS INVAGINATUS "Dens in Dente" Pathogenesis:  - 11 - It is caused by the invagination of all layers of enamel organ into the dental papilla during odontogenesis, resulting in the formation of an enamel-lined cavity that communicates with the surface. Radiographically; a tooth-like structure appears within the pulp of the involved tooth and hence the term "dens in dente" was used. Clinically: The dens in dente may appear as either a normally shaped or malformed crown that exhibits a deep pit in the area of the cingulum. Food debris: tends to lodge in the pit: and usually affects the upper lateral incisors bilaterally. causing caries, pulp infection, and periapical disease. DENS EVAGINATUS Dens evaginatus appears as an accessory cusp on the occlusal surface between the buccal and lingual cusps of premolars, unilaterally or bilaterally. A pulp horn may extend into the extra cusp. Pathogenesis: It is thought to be due to the proliferation and evagination of enamel epithelium during tooth development. CONGENITAL SYPHILIS Syphilis is a contagious venereal disease caused by the spirochetes "treponema pallidum". Prenatal syphilis is transmitted from an infected mother to her fetus via the placenta. Children born to syphilitic mothers may show characteristic abnormalities in the size, shape, and structure of some of their permanent teeth. The deciduous dentition of such children is normal because it develops at an early stage of intra-uterine development. If the fetus becomes infected at such an early stage, abortion follows. Teeth almost consistently affected are the upper first permanent incisors and the first molars in both jaws. Less frequently lateral incisors or canines may be affected.  - 12 - Hutchinson's Teeth The permanent incisors are barrel-shaped: their mesial and distal surfaces taper toward the incisal edge giving a "screw-driver" appearance. The incisal edges usually have a central notch. The mesial and distal incisal angles are rounded. The incisors may show enamel hypoplasia. Moon's and Mulberry Molars The first permanent molars show a constricted occlusal surface and rounded angles and is dome-shaped (Moon's molars); or their occlusal surfaces may be rough, pitted and exhibit multiple, irregular tubercles replacing their normal cuspal pattern (mulberry molars). ABNORMALITIES IN THE STRUCTURE OF TEETH Developmental disturbances that may affect the structure of teeth, whether they may affect the enamel, dentine or both may be: Hereditary or Acquired In the Acquired cases: a. local factor that usually affects individual teeth, b. general systemic factor that will affect all the teeth undergoing development at the time of disturbance. The following criteria are useful in differentiating hereditary structural defects from those resulting from acquired factors. 1. Hereditary structural anomalies usually affect: both the deciduous and permanent dentitions, while Acquired (environmental) factors result in: only one dentition, usually the permanent 2. Hereditary anomalies usually affect either enamel or dentine, while Acquired (environmental) factors affect both enamel and dentine. 3. Hereditary anomalies usually produce: diffuse or vertically oriented enamel defects,  - 13 - while Acquired (environmental) factors produce: horizontally oriented defects. Table (1): Differences between hereditary and acquired defects. Hereditary defects Acquired defects Affect both dentitions Affects only one dentition usually Deciduous. and permanent the permanent Usually affects all teeth Usually affects single or group of teeth Affect enamel or dentine Affects both enamel and dentine Produce diffuse or vertically or Produce horizontally oriented pits or oriented pits or defects. defects. DEVELOPMENTAL DEFECTS OF ENAMEL Classification of enamel defects : I. Hereditary (Amelogenesis inperfecta). II. Acquired factors: 1. Local factors: a. Trauma. b. Infection. c. Irradiation. 2. Systemic factors: a. Nutritional deficiencies: vitamins (A & D) calcium, phosphorus. b. fevers (measles,). c. Hormonal disturbances d. Infantile gastro-intestinal disturbances. e. Congenital syphilis. f. (fluoride, tetracyclines, cytotoxic drugs). g. premature birth, h. May be associated with idiopathic causes:(Cleidocranial dysplasia) Hereditary Enamel Defects  - 14 - "Amelogenesis Imperfecta" Amelogenesis imperfecta is a hereditary familial disorder of enamel formation affecting both the primary and permanent dentitions. Types of Amelogenesis Imperfecta: 1) Hereditary enamel hypoplasia. 2) Hereditary enamel hypo-calcification. 3) Both types may coexist. Hereditary enamel Hypoplasia: The defect is mainly quantitative due to a decrease in the amount of organic matrix formed. The teeth erupt with insufficient amount of enamel, The remaining enamel is hard, smooth, reflect light, and translucent. Teeth tends to be small in size. Hereditary Enamel Hypocalcification: The amount or thickness of the enamel matrix formed is normal as the defect is a failure in normal mineralization. Enamel lacks its surface luster or gloss and the color of the teeth varies from white opaque to yellow-brown. Enamel is soft and friable, so that it fractures exposing dentine which as well wears down rapidly often being leveled with the gum line. Differences between hereditary enamel hypoplasia and hereditary enamel hypocalcification. Hereditary enamel Hereditary enamel hypoplasia hypocalcification - Nature of defect Quantitative Qualitative - Amount of matrix Deficient Normal - Mineralization Normal Defective - Thickness Thin enamel Normal thickness - Hardness Normal hardness Soft enamel  - 15 - - surface texture Smooth in unpitted areas Rough - Translucency Translucent Opaque white - surface luster Shiny Dull - radiographically Enamel of normal Decreased radiopacity, radiopacity enamel Acquired Enamel Hypoplasia acquired defects of enamel are usually confined to the permanent dentition. Except in cases of endemic fluorosis, The deciduous dentition escapes Local Factors Acquired localized enamel hypoplasia involving only one or two teeth is known as "Turner's tooth". It results from trauma or localized infection during tooth formation. Trauma: Traumatic injuries to upper deciduous incisors may take a path deeply into their sockets resulting in injury manifested as a yellowish or brownish stain or pigmentation of the enamel, usually on the labial surface. Infection: Periapical infection of a deciduous tooth, and usually one of the molars, may reach the underlying developing tooth germ of the succeeding premolar and give rise to enamel hypoplasia of that tooth. Severe infections during the time of tooth development may also affect the structure of dentin as well as enamel. Systemic Factors Acquired generalized enamel hypoplasia may occur as a result of systemic environmental factors such as a deficiency in minerals The hypoplasia will usually present itself clinically as horizontally oriented rows of pits on the enamel surface that correspond to time of development, duration and severity of the environmental factors.  - 16 - If the duration of the environmental insult is brief, the line of hypoplasia is narrow, whereas a prolonged insult produces a wider zone of hypoplasia and may affect more teeth. Dental Fluorosis: Mottled Enamel Ingestion of drinking water containing fluoride at levels greater than 1.5 part per million during the time of tooth formation may result in enamel hypoplasia or hypocalcification, also known as "dental fluorosis". Dental fluorosis affects mainly permanent teeth; deciduous teeth are rarely affected. The incidence and severity of mottling increase in line with the increase in the fluoride content of drinking water (content reaches or exceeds 4.5 ppm Mottled teeth show an increased resistance to dental caries. Pathogenesis: Increased fluoride levels interfere with ameloblastic function, which adversely affects both enamel matrix formation and calcification Clinically: Enamel mottling may be graded as follows: 1. Very mild: Small white opaque areas involving less than 25% of the surface area of the tooth. 2. Mild: White opaque areas involving more than 25% but not exceeding 50% of the surface area of the tooth. 3. Moderate: The whole enamel may be affected with white chalky areas and yellowish, or brown staining. 4. Severe: The enamel is stained black, brittle, and easily chipped away from the tooth surface. Tetracycline Pigmentation Tetracycline binds to calcifying tissues of developing teeth, in higher doses, which may cause stained, hypoplastic enamel. Tetracycline is deposited along the incremental lines of dentine and enamel with the result that the whole tooth may be discolored. DEVELOPMENTAL DEFECTS OF DENTINE  - 17 - DENTINOGENESIS IMPERFECTA "Hereditary Brown Opalescent Dentine" It is an inherited disorder of dentine formation. Clinically: Both deciduous and permanent dentitions are affected. The teeth color ranging from bluish-gray to brown The crowns of the teeth are slightly smaller than normal, with a constricted neck resulting in a bulbous appearance. ,short roots Radiographic features: Small bulbous crowns. The teeth show partial or total obliteration of the pulp chambers The roots are short Narrow root canals Histological features: Normal enamel. The amelodentinal junction is straight rather than scalloped. The mantle dentine is normal. The deeper dentin shows the following: - Dentinal tubules are fewer in number, widely spaced, larger in diameter than normal, and irregular. - Poorly calcification with large areas of interglobular spaces. The pulp shows the following: - Numerous pulp stones. - Obliteration of pulp chamber and root canal by poorly formed dentine. - Absence of odontoblastic layer. SHELL TEETH Discovered in Brandywine isolate ….in state of Maryland, USA. It is a very rare abnormality, clinically similar to dentinogenesis imperfecta except that the pulp chamber is not obliterated, the dentine being quite thin and forming a shell around the wide pulp.  - 18 - Early pulp exposure is common sequela of caries affecting these teeth. The roots of the teeth are extremely short. Histologic features: Normal enamel. The peripheral layer of mantle dentine is normal. The pulp: is very wide, it lacks a normal odontoblastic layer and it consists of coarse fibrous connective tissue Prof. Dr. Salah Hamed