Classification of dental anomalies
I . Anomalies of number
II. Anomalies of size
III. Anomalies of shape
IV. Anomalies of structure Managements of all defects
Stage of Tooth Development
Initiation →
Proliferation →
Morphodifferentiation →
Histodifferentiation →
Apposition →
Maturation →
Dental Defects
number
Size
shape
structure & color
structure
structure
I. ANOMALIES OF NUMBER Defects in initiation of tooth germ
Etiology: • Hereditary • Physical disruption of dental lamina • Overactive dental lamina • Failure of dental lamina induction
A. Decrease in Number of Teeth (hypodontia)
• Oligodontia ( partial anodontia) • Anodontia
Clinical picture
• Varies with racial group • Rare in primary teeth • Female ˃male • Teeth affected =Maxillary lateral incisor, • Unilateral or bilateral
A. Associated with systemic disease: • Hereditary ectodermal dysplasia • Down’s syndrome • Ellis van creveld syndrome • Crouzon`s disease B. Unassociated with systemic disease • Cleft palate
Hereditary Ectodermal Dysplasia ( streeter’s syndrome)
Definition Hereditary condition in which there are abnormalities of at least 2 or more ectodermal structures e.g. hair, nails, teeth, sweet glands. Clinically • Males are more affected. Females are carriers or show mildest form of disease. • Hair: scanty, fine, sparse • Sweat glands: inability to sweat → can not tolerate heat • Sebaceous glands: lack of sebum→ dry skin
• Mucous glands: absent in nose & pharynx → Rhinitis • Nails: defective , anonychia (absence of nails) • Salivary glands → xerostomia • Teeth: anodontia or hypodontia, maximum 4 teeth, most deciduous teeth but few or no permanent teeth -primary teeth: show ankylosis without permanent successors. -Permanent teeth: conical, pegshaped, small→ Dracula like appearance
College of Dentistry,Al Jouf University
• alveolar process: fails to develop, resorption of alveolar bone causes: i. Depressed nasal bridge ii. Protrusion of lips ( due to over closure) iii. ↓ vertical dimension of face( Elderly profile) Palate: high arched Mental retardation: some cases
Treatment Objectives of Hypodontia:
• Provide adequate function • Promote speech development ( 2-3 yr. Age) • Maintain vertical dimension • Esthetic
Management of Hypodontia:
• Composite buildups of conical teeth • Surgical exposure of impacted teeth • Orthodontic adjustment of spaces • Prosthetic treatment, implants (adolescent)
• Missing laterals with sufficient space : space maintainer for future bridge or implant
• Missing laterals with insufficient space : canine movement & reshaping
B.Increase in Number of Teeth( Hyperdontia) 1. Predeciduous dentition • Present at birth(natal teeth) • Rudimentary in size • Weakly attached to gum : must be extracted otherwise it may be inhaled or ingested by infant and affect feeding. • Should be differentiated from prematurely erupted true deciduous dentition • ( neonatal)(erupt within 30 days of life)
2. Supernumerary(extra teeth) i. Hereditary ii. Associated with: • Cleidocranial dysplasia( dysostosis) • Gardner’s syndrome ( multiple polyps in the colon + tumors outside colon ) • Down’s syndrome • Crouzon’s syndrome ( branchial arch syndrome) • Sturge - Weber syndrome • Oral - facial - digital syndrome • Hallermann - Streiff syndrome
Cleidocranial dysplasia
Is congenital disease characterized by deficient growth of bones developed in membranes( cranial vault, clavicle, maxilla & mandible) Clinically: • Shoulder( clavicle): Hypoplastic, aplastic in 10% of cases→ can approximate shoulder together.
• Skull: Frontal & parietal bossing Fontanells & cranial sutures→ delayed closure • Maxilla: Hypoplasia, narrow, V-shaped, high arched palate • Mandible: pseudo prognathism • Teeth: Delayed eruption, many unerupted supernumerary or supplemental teeth, multiple dentigerous cyst.
Site: • Mesiodens- most common( ant. Max. midline) • Paramolars in molar region(adjacent) • Distomolars in molar region( distal) • Mand. Bicuspid(premolar) area
Shape: • Supplemental ( similar morphologically to normal teeth, premolar area. • Conical, peg shaped • Tuberculated • Odontome Clinical significance: • Supernumerary may fail to erupt→ delay eruption of permanent which is developing deeper within jaw e.g. mesiodens prevent or delay eruption of 1│1 • Routine radiographic survey
Clinical problems of supernumerary Teeth: •Failure of eruption – tuberculate type •Displacement / rotation •Crowding •Abnormal diastema / premature space closure •Dilaceration / abnormal root development •Cystic formation •Eruption into nasal cavity
Management of Supernumeraries
• Occlusal films ( bucco- lingual & anteroposterior) + periapical Sup.- Inf. & ant. - post.) • occlusal radiographs gives clearer view / tube – shift technique • Panoramic view for vertical orientation • Extraction: Careful surgical removal of impacted teeth to
II. ANOMALIES OF SIZE ( Defect in proliferation of tooth germ)
1. Macrodontia (Megadontia) 2. Generalized/Localized i. Associated with hormonal disturbance e.g. pituitary gigantism, hemifacial hyperplasia , hereditary gingival fibromatosis. • Fusion of right & left dental lamina • prematurely • Associated with other midline defects – cleft palate.
Management of Macrodontia
• Reduce tooth size( only small change can be achieved). • Too large teeth & malocclusion → extraction & prosthesis
2. Microdontia
• There is association between microdontia & hypodontia. • i. Generalized: associated with Down’s syndrome , Ectodermal dysplasia, Pituitary dwarfism, Microcephaly, hemifacial hypoplasia.
• ii. Localized: peg- shaped lateral incisor, 3rd molar
Management of Microdontia
• Composite resin, porcelain crowns, porcelain veneers. • Orthodontic alignment & extraction may be required • Implant • Auto-transplantation
III. ANOMALIES OF SHAPE defective in morphodifferentiation
Etiology • Hereditary • Systemic diseases • Trauma
1. Double teeth( connation)
i. Gemination/Twining • Is budding of a 2nd tooth From a single tooth germ. Tooth appear to have 2 crowns, no. of teeth is normal. Site: anterior teeth, both dentition • Twinning: more complete than gemination→2 separate teeth from 1 tooth germ (1 extra tooth • in the arch).
ii. Fusion • When 2 teeth are joined together • result from physical force or pressure producing contact of developing teeth. • The tooth arisen from 2 teeth germ iii. Concresence Is joinig of 2 teeth by cementum along their roots, after root formation has been complete Result from trauma Rare in children, 2nd, 3rd permanent molars in adults, mand. premolars
Management
• Diagnose whether single canal or Separate canals by periapical, C. beam • Central groove is prone to caries→ Fissure sealant is recommended • Fused teeth: Hemisectioning ( surgical separation) Endodontic treatment Orthodontic alignment Restorative: Crown reshaping
2. Dilaceration
• Is presence of sharp bend along long axis of tooth in crown or root. • Causes: trauma during tooth development or secondary to bone lesion • Clinical significance: tooth involved will not erupt due to direction of root → surgical Removal.
3. Dens Invaginatus (dens in Dente)
• Is developmental invagination of cingulum pit • Site: max. lateral incisor, max central incisor, Canine. • Clinical significance: food become entrapped → early caries→ pulpitis → pulp necrosis soon after eruption. • Management Newly erupted→ seal palatal fissure Evident caries→ acid etched retained composite Symptomatic → favorable RC morphology →RCT Complex internal anatomy →Extract
➢Coronal
➢Radicular
4. Dens Evaginatus(occlusal enamel drop) & Talon cusp • Is accessory cusp that arise from occlusal surface between buccal & lingual cusp of premolars Synonyms : occlusal tubercle, Leong‟s PM, dilated composite odontoma, tuberculated PM,occlusal enamel pearl, evaginated odontoma • When present in cingulum of max. incisors = Talon cusp • Contains 3 dental element (enamel-Dentin-pulp) • Occur commonly in mongoloid descent.
Clinical significance: Tubercle can easily fracture(due to occlusal Interference) if pulp exist→ pulp necrosis Treatment: Vital teeth - Selective grinding followed by fissure sealing Hill&Bellis(1984) Selective pulpotomy to allow normal formation : if diagnosed early Nonvital teeth Apexification followed endodontic treatment
3 PATTERNS OF TALON CUSPS Trace talon Semi-talon Talon Forms : T –form ; Y -shaped Syndromes Rubinstein – Taybi, Struge – Weber Orofacialdigital syndrome
5. Taurodontism • Are teeth having long anatomical crown, large pulp chamber and short root(s) resembling teeth found in bulls • Site: molars • Failure of HERS to invaginate at the proper horizontal level • Shaw‟s classification ( 1928 ) • Basis of apical placement of pulp chamber
Conditions demonstrating Taurodontism
• Ectodermal dysplasia (hypohidrotic type) • Down’s syndrome • Amelogenesis imperfecta Type IV • klinefelter’s syndrome • Rickets • Oro - facial - digital syndrome • Hypophosphatasia
I. ANOMALIES OF STRUCTURE Amelogenesis imperfecta:
Autosomal dominant, autosomal recessive, Xlinked.
Gene: Amelogenin (AMG), enamelin (ENAM).
Affects both dentitions
Sensitive teeth, Susceptible to wear
Delayed or partial eruption of premolars and permanent molars.
Turner‟s Hypoplasia
Local factors Trauma Infection
Enamel Hypoplasia Fluorosis
Tetracycline Mechanism Toxic to ameloblasts Disruption of mineralization Chelating Ca2+ of hydroxyapatite
Dentinogenesis imperfecta:
Autosomal dominant
Gene: dentin sialophosphoprotien (DSPP)
Both dentitions are affected
Blue-gray or brown teeth
Susceptible to extreme wear
Pulpal obliteration and dental abscesses.
Associated with Fractures-Osteogenesis imperfecta.
Dentin dysplasia 1. Radicular Dentin dysplasia
2.Coronal dentin dysplasia (Thistle tube)
Regional Odontodysplasia/Ghost teeth
References:
Pinkham JR, Casamassimo PS, Fields HW, McTigue DJ, Nowak AJ. Pediatric Dentistry: infancy through adolescent. 4th edition, Missouri: Elsevier; 2005.
McDonald RE, Avery DR, Dean JA. Dentistry for the child and adolescent. 9th edition, St Louis, Missouri: Mosby, Inc; 2011.