School of Dentistry Wuhan University 2006 Hong Qian Pediatric dentistry School of Dentistry Wuhan University 2006 Hong Qian

Abnormality of tooth development Abnormality of tooth number congenital absence of teeth supernumerary tooth Abnormality of tooth form double teeth geminated teeth fused teeth concrescence of teeth peg-shaped lateral incisor dens invaginatus dens evaginatus dilaceration taurodontism Abnormality of tooth structure enamel hypoplasia and hypomineralisation dentinogenesis imperfecta intrinsic staining of teeth Abnormality of tooth eruption natal and neonatal teeth delayed eruption submerged teeth ectopic eruption retained teeth

Abnormality of tooth number Congenital absence of teeth Total anodontia: congenital absence of all teeth Partial anodontia (hypodontia, oligodontia) : congenital absence of one or more teeth

Anodontia Treatment Depends on severity of the case No treatment Prosthetic replacement Prognosis: good 

Supernumerary tooth Definition Additional to normal series and can be found in almost any region of dental arch. Etiology ※ A dichotomy of tooth bud. ※ Local, independent, conditioned hyperactivity of dental lamina. ※ Heredity. More common in relatives of affected children than in general population.

Supernumerary tooth Prevalence 0.8% of primary dentitions and 2.1% of permanent dentitions. Single or multiple, unilateral or bilateral, erupted or impacted, and in one or both jaws. Associated with cleft lip and palate, cleidocranial dysplasia, and Gardner syndrome.

Supernumerary tooth Conical Root formation ahead of or at an equivalent stage to that of permanent incisors. Found high and inverted into palate or in a horizontal position. Mostly long axis of tooth is normally inclined. Can result in rotation or displacement of permanent incisor, rarely delays eruption.

Supernumerary tooth Tuberculate More than one cusp or tubercle Barrel-shaped and may be invaginated Root formation delayed Often paired and rarely erupt and frequently associated with delayed eruption of incisors Commonly located on palatal aspect of central incisors

Supernumerary tooth Supplemental Duplication of teeth in normal series and found at the end of a tooth series. Most common: permanent maxillary lateral incisor. Majority found in primary dentition are of the supplemental type and seldom remain impacted.

Supernumerary tooth Odontoma Tumor of odontogenic origin. Lesion composed of more than one type of tissue and called a composite odontoma. Complex composite odontoma: diffuse mass of dental tissue which is totally disorganized. Compound composite odontoma: malformation which bears some superficial anatomical similarity to normal tooth.

Problems associated with supernumerary tooth Failure of Eruption Displacement Crowding Pathology: dentigerous cyst formation Alveolar bone grafting Implant site preparation Asymptomatic

Indications for supernumerary removal central incisor eruption delayed or inhibited; evident altered eruption or displacement of central incisors; there is associated pathology; active orthodontic alignment of an incisor in close proximity to supernumerary is envisaged; its presence would compromise secondary alveolar bone grafting in cleft lip and palate patients; present in bone designated for implant placement; spontaneous eruption of supernumerary occurred.

Abnormality of tooth form Double teeth—geminated teeth Make two teeth from one enamel organ. Two completely or incompletely separated crowns with a single root and root canal. Causes: trauma and familial tendency. Seen in deciduous and permanent dentition.

Double teeth—fused teeth Joining of two tooth germs results in a single large tooth. Involve entire length of teeth, or only roots. Shared or separate root canal. Causes: trauma and familial tendency. In deciduous and permanent dentition. Difficult to differentiate fusion of supernumerary teeth from gemination.

Double teeth—concrescence of teeth Concrescence is fusion of adjacent already-formed teeth by cementum. Take place before or after eruption. A form of fusion where teeth are united by cementum only. Causes: trauma or crowding of teeth.

Peg-shaped lateral incisor Reduced mesio-distal diameter and proximal surfaces converging markedly in incisal direction. Prevalence: 1% to 2%. Associated with other dental anomalies like tooth agenesis, maxillary canine-first premolar transposition, palataly displacement of maxillary canine teeth and mandibular lateral incisor- canine transposition.

Peg-shaped lateral incisor Treatment Moving maxillary canines forward and reshape them with acid etch technique and bonded composite resin to simulate lateral incisors. Restoring missing tooth structure by increasing size of a peg-shaped lateral incisor. Placing full-coverage crown on lateral incisors.

Dens evaginatus Definition A developmental anomaly in which focal area of crown projects outward and produces a nodule composed of pulpal horn and normal layers of enamel and dentin. The nodule (talon cusp) can result from abnormal proliferation of enamel epithelium from interior of stellate reticulum of enamel organ . Its etiology is unknown. North American Indian and Asian background

Dens evaginatus Problem: fairly soon after tooth eruption this extra cusp can be ground off during mastication, resulting in pulp exposure. Early pulpal necrosis leads incomplete root development and open apex situation, the most difficult endodontic cases to apexify. Surgical treatment is very difficult because of minimal root length and thin dentinal walls.

Dens evaginatus Clinical features Primarily premolars    Usually bilateral    Conical, tuberculated projection from central fissure of occlusal surface    Can interfere with tooth eruption thus causing tooth displacement   

Dilaceration Definition A sharp bend or angulation of root portion of a tooth. Etiology: Trauma during tooth development or idiopathic

Dilaceration Clinical features Rare in deciduouos teeth    History of trauma or presence of a cyst, tumor, or odontogenic hamartoma    Many are nonvital and associated with periapical inflammatory lesions    Frequently maxillary incisor or mandibular anterior dentition

Dilaceration Treatment Extraction for normal eruption of succedaneous teeth    Usually no therapy for dilaceration of permanent teeth    Orthodontic therapy for grossly dilacerated teeth  Prognosis: good

Abnormality of tooth structure Enamel hypoplasia and hypomineralisation Local Developing permanent teeth may be damaged by trauma or by infection associated with their predecessors. Systematic genetically-transmitted factors, inborn errors of metabolism, neonatal disturbances, endocrinopathies, gastrointestinal disease, liver disease and excessive ingestion of fluoride. Hereditary

Enamel hypoplasia and hypomineralisation Distribution Permanent teeth First molars -occlusal 1/3 Central incisors and mandibular lateral incisors -incisal 1/3 Canines -tips of cusps Primary teeth Molars -cervical-middle 1/3 Canines -cervical-middle 1/3 Incisors -cervical 1/3

Enamel hypoplasia Clinical features pits, grooves, lines or larger areas of missing enamel surface    reduction in enamel thickness    possible occlusal distortion, aesthetic problems, sensitivity    yelllowish or brownish discoloration    may be localized or present on numerous teeth and all or part of surfaces of each affected tooth may be involved

Enamel hypomineralisation Poor appearance of anterior teeth Chipping of enamel, leaving rough surfaces Attrition of occlusal enamel Exposure of dentine—tooth sensitivity Attrition of dentine

Dentinogenesis imperfecta definition A hereditary defect consisting of opalescent teeth composed of irregularly formed and undermineralized dentin that obliterates coronal and root pulpal chambers.

Dentinogenesis imperfecta Treatment composite resin restorations, laminate veneers, stainless steel crowns on molars, and over dentures  Prognosis:  good with early diagnosis

Intrinsic stains Intrinsic Stains Located within tooth anatomy, can be of varied origin. May result from pre-eruptive or post-eruptive causes.

Intrinsic stains Hereditary conditions Hereditary conditions such as porphyria and phenylketonuria can result in a deposition of colored materials in teeth. Other pre-eruptive staining include amelogenesis imperfecta and dentinogenesis imperfecta.

Tetracycline Staining Use of tetracycline during period of tooth formation - including last half of in utero development - leads to its incorporation into tooth structure. Resulting appearance depends both on intensity of use and type of tetracycline employed. Tetracycline can be transferred through placenta and enter fetal circulation. Discoloration may be generalized or limited to a specific part of individual teeth that were developing.

Ingestion of fluoride Ingestion of excessive amounts of fluoride during tooth formation can lead to areas of lighter appearing enamel. These spots are chalky white and cannot be bleached to match surrounding enamel. Referred to as 'mottled enamel'. Whitening does not remove white spots but lightens background so they are less noticeable. Secondary stains around these white areas are readily bleached to produce appearance less noticeable.

Abnormality of tooth eruption Early eruption-natal tooth and neonatal tooth (1) Natal teeth already present at the time of birth. Neonatal teeth erupt during first 30 days after birth. Associated Conditions Cleft Palate Ellis-van Crevald Syndrome Hallermann-Streiff Syndrome Pachyonychia Congenita Syndrome

Natal tooth and neonatal tooth (2) ⊙ Incidence varies from 1:1000 to 1:30 000. ⊙ Either a premature eruption of normal teeth (up to 95%) or supernumerary (5%). ⊙ Removed only if they are extremely mobile. ⊙ Supernumerary teeth need extraction if confirmed by radiography.

Natal tooth and neonatal tooth (3) Generally develop on lower gum where central incisors will be. Little root structure and attached to margin of gum by soft tissue and often wobbly. Not well formed but firm enough, may cause irritation and trauma to infant's tongue while he is nursing.

Natal tooth and neonatal tooth: Home care and treatment If not removed, keep them clean by gently wiping gums and teeth with clean, damp cloth. Examine infant's gums and tongue frequently to make sure teeth are not causing injury. See a dentist if an infant with natal teeth that develops a sore tongue or mouth; other symptoms develop.

Delayed eruption of deciduous or permanent teeth Etiology for incisors Delayed resorption of a primary incisor following trauma and death of pulp. Dilaceration Supernumerary teeth Very early loss of a primary tooth, followed by formation of bone in tooth socket.

Delayed eruption Etiology for canines and premolars Abnormal eruption path of maxillary permanent canines. Impaction against other teeth due to abnormal angulation or crowding. Retarded resorption of a primary molar. Submerged primary molars

Delayed eruption Etiology for molars Impaction against other teeth, especially affecting third molars. Other conditions, such as a dentigerous cyst, may affect any tooth.

Delayed eruption Treatment for maxillary permanent canines (1) Extract maxillary primary canines and surgically expose crowns of permanent canines in a child aged 10-13 years if permanent canine might have erupted normally following extraction.

Delayed eruption Treatment for maxillary permanent canines (2) Retain maxillary primary canines and extract permanent canines If position of a maxillary permanent canine is unfavourable If its root development has reached an advanced stage, prognosis is poor for normal eruption or for repositioning following extraction of its predecessor.

Delayed eruption Treatment for maxillary permanent canines (3) Extract maxillary primary canines and transplant permanent canines if position of maxillary permanent canine is unfavorable for orthodontic alignment.

Ectopic eruption of first permanent molars Definition Ectopic eruption is a developmental disturbance in eruption pattern of permanent dentition. Molar erupts at a mesial angle to normal path of eruption, results in cessation of eruption and atypical resorption of neighboring primary molar. Permanent tooth may get locked in this position (irreversible) or correct itself without treatment and erupt into normal position (reversible).

Ectopic eruption Prevalence Prevalence: approximate 4% rate Almost 60% were reversible. Mostly seen in maxilla, unilateral or bilateral. Could not identify significant differences between different racial groups. More frequent occurrence in cleft lip and palate patients

Ectopic eruption Etiology Mesial angle of first permanent molar is clearly increased. Extraction of second deciduous molar had no influence on angulation. Cause of this pronounced mesial inclination could not be established. Width of first permanent molar is increased compared to children with normal eruption. Size of central incisors cannot be used to predict ectopic molar eruption.

Ectopic eruption Clinical implication A 3-6 month observation period if resorption on primary molar is not too severe. Cases that self correct usually correct before 7 years of age.

Ectopic eruption Treatment Treatment goals for irreversible ectopic eruption are movement of permanent molar distally in order to regain space and correction of mesial tipping of permanent molar to allow normal eruption. Disimpact tooth using soft brass ligature wire if tooth is impacted against crown rather than root of primary molar. Distal slicing of primary molar is not indicated because it will result in space loss and permanent molar erupt in tipped position that favor development of malocclusion.

Retained deciduous tooth Definition Deciduous teeth retained beyond time of exfoliation are diagnosed as retained deciduous tooth. Causes: absence of bud of permanent tooth or abnormal displacement of bud in embroyonic life.