Therapeutic dentistry department Un-carious defects of teeth. Classification. Pathomorphology, clinic and diagnostics of defects that are developed before and after eruption of teeth. Treatment. Therapeutic dentistry department

Uncarious lesions of teeth Developmental Alterations of Teeth Post-eruptive Alterations of Teeth

Developmental Alterations of Teeth I. Lesions that occur in the stage of dental follicle development, before eruption: 1. hypoplasia; 2. hyperplasia of enamel (enamel pearls); 3. endemic fluorosis; 4. developmental disturbances and disorders of eruption; 5. genetic disturbances of tooth development.

Posteruptive Alterations of Teeth II. Lesions that occur after teeth have been erupted: 1. tooth wear: attrition, abrasion, wedge-shaped defect; 2. erosion; 3. necrosis of hard tooth tissues; 4. hyperesthesia; 5. trauma of teeth; 6. fluorosis; 7. discolorations of teeth: intrinsic stains extrinsic stains

LOCALIZED DISTURBANCES IN ERUPTION DEVELOPMENTAL DISTURBANCES AND DISORDERS OF ERUPTION LOCALIZED DISTURBANCES IN ERUPTION PRIMARY IMPACTION- Teeth cease to eruption before emergence ANKYLOSIS -Cease of eruption after emergence and anatomic fusion of tooth cementum or dentin with alveolar bone

Impaction 3rd molars, maxillary canines, mandibular premolars, mandibular canines, maxillary premolars, maxillary central incisors, maxillary lateral incisors, and mandibular second molars; usually angulated or diverted Factors associated with impaction: Crowding and deficient maxillofacial development Overlying cysts or tumors Trauma Reconstructive surgery Thickened overlying bone or soft tissue A host of systemic disorders, diseases or syndromes

Classification : Partially erupted or full bony impaction according to angulation: Mesioangular, distoangular, vertical, horizontal or inverted

ANKYLOSIS Infraocclusion, secondary retention, submergence, reimpaction, reinclusion

ANKYLOSIS Clinical And Radiographic Features Pathogenesis is unknown, may be secondary to many factors and result in PDL barrier deficiency. May occur at any age, any tooth Most affect 8~9yr-old children and D , E , D , E PDL absent Occlusal, periodontal problems, impaction of the underlying teeth Treatment and Prognosis Variable : extraction, orthodontics, segmental osteotomy

Premature eruption Neonatal teeth: within 30 days Natal teeth: newborns Most are prematurely erupted deciduous teeth Removal only if mobile and at risk of aspiration

Disturbances in tooth form may present as dilacerated teeth, double teeth, dens invaginatus and enamel pearls Anhidrotic ectodermal dysplasia showing conical teeth, giving an undesirable, Dracula-like appearance.

Gemination, Fusion, Concrescence

Gemination single tooth germ division tooth no.: normal single root & root canal + 2 complete or incomplete separated crowns tooth no.: normal twinning

Fusion Union of 2 separate tooth germs Contact of tooth germ before calcified Confluent of the dentin Complete- form a single tooth Incomplete- after calcified begins Tooth no. : less one

Concrescence Fusion after root formation Cementum united Traumatic injury or crowding Pre-extraction x-ray check

Talon cusp Eagle’s talon Lingual projection from the cingulum area of ant. teeth Most contain a pulp horn Both in deciduous & permanent dentition

Dens invaginatus ( central tubercle, occlusal tuberculated premolar; Leong’s premolar; evaginated odontome; occlusal enamel pearl ) An accessory cusp or a globule of enamel on central groove or buccal cusp of premolars or molars; unilateral or bilateral. 15% in Asians, rare in whites

Dens invaginatus Kaohsiung Medical University, Oral Pathology and image Diagnosis Dept.

Shovel-shaped incisors

Dens in dente Tooth within a tooth, incidence 5% (Dens invaginatus; Dilated composite odontome) Tooth within a tooth, incidence 5% Invagination of the enamel organ into dental papilla before calcification Coronal type: 3 types maxillary lateral incisors are common

Dens invaginatus, coronal type II

Dens invaginatus Radicular type Hertwig’s sheath invagination Food deposition→ caries → pulp infection Restorated as soon as possible

Taurodontism “Bull-like “ teeth Bi- or trifurcation near the apex Pulp chamber : greater apico-occlusal height and no constriction at the cervical of the tooth

Enamel pearl. There is a small mass of enamel at the root Enamel pearls Enamel pearl. There is a small mass of enamel at the root bifurcation

Supernumerary roots Any tooth may develop accessory roots No rtg required, but critical important in endodontic procedure

Dilaceration Angulation, sharp bend of root or crown Trauma during tooth is forming Pre-extraction x-ray check

DISTURBANCES IN THE NUMBER OF TEETH Missing teeth 1.6-9.6% , excluding 3rd molars, female predominance Hypodontia: missing one or more teeth Oligodontia: missing 6 or more teeth Anodontia: total missing 1.6-9.6% 4

Hypodontia

Congenital absence of lateral incisors with spacing of the anterior teeth.

Supernumerary teeth, hyperdontia Mesiodens Paramolar Supplemental teeth

Mesiodens The most common in supernumerary. Premaxillary area , usually between upper central incisors Cone-shaped crown & short root One or two in number

Kaohsiung Medical University, Oral Pathology and image Diagnosis Dept.

DISTURBANCES OF TOOTH SIZE Microdontia True: 1.General -pituitary dwarfism 2. Single -peg lat., 3rd molar Relative microdontia

Macrodontia True macrodontia : 1. Generalized-pituitary gigantism 2. Localized- single, hemifacial hypertrophy Relative macrodontia: small jaw, child

Disturbances in the structure of teeth Disturbances of enamel ■ Genetic disturbances - Amelogenesis imperfecta. ■ Local disturbances: - Infection. - Trauma. - Idiopathic. ■ Generalised disturbances: - Infections. - Fluorosis. - Neonatal events, e.g. premature birth, rhesus incompatibility.

Amelogenesis imperfecta (Hereditary enamel dysplasia; Hereditary brown enamel; Hereditary brown opalescent teeth) Defects in-- Formative stage→hypoplastic type → defective formation of matrix Calcification stage →hypocalified → defective mineralization of formed matrix Maturation stage → hypomaturation → enamel crystallites remain immature Genes mutation : AMELX, ENAM, MMP-20, KLK4, DLX3

1. Hypoplastic type Thin enamel with pitted, rough or smooth & glossy surface; yellowish to brown undersized, squared crown, lack of contact flat occlusal surface & low cusps, attrition

Hypoplastic type Kaohsiung Medical University, Oral Pathology and image Diagnosis Dept.

Hypoplastic type

2.Hypomaturation normal thickness of enamel, but mottled surface; cloudy white, yellow or brown, opaque in color softer than normal same density as dentin

Hypomaturation type Kaohsiung Medical University, Oral Pathology and image Diagnosis Dept.

3.Hypocalcified type normal thickness of enamel, density less than dentin normal size & shape when erupt, abrade or fracture away rapidly permeability increase, darkened & stained 4.Hypomaturation-hypocalcified with taurodontism

Hypocalcified type

Tricho-dento-osseous syndrome Hypoplastic-Hypomaturation type

Factors associated with enamel defects ACQUIRED DISTURBANCES OF ENAMEL FORMATION Factors associated with enamel defects Local- 1.Local acute mechanical trauma 2. Electric burn 3. Irradiation 4. Local infection: periapical inflammatory disease

Acquired disturbances of enamel formation Environmental enamel defects: 1.Hypoplasia: pits, grooves or large area of missing enamel 2. Diffuse opacities: variation in translucency, normal thickness, white opacity without clear boundary 3. Demarcated opacities: increased opacity, a sharp boundary with adjacent normal enamel, normal thickness

Acquired disturbances of enamel formation Most acquired enamel defects result in areas of HYPOPLASIA, which may be due to either a defect in matrix production or a defect in mineralisation. Localized - only a single tooth is affected Generalized - several teeth are affected

Turner’s hypoplasia, Turner’s tooth Permanent teeth Periapical inflammatory disease of the overlying deciduous tooth, less frequently in anterior teeth Traumatic injury- not rare -45% children sustain injury to their deciduous teeth, 23% permanent teeth development disturbed Turner’s hypoplasia secondary to previous trauma

Turner’s teeth

Generalized defects are sometimes referred to as chronological hypoplasia The overwhelming majority of chronological hypoplasia are the result of disturbances in the first 10 months of life and the teeth usually affected are: ■ The first permanent molars. ■ Upper central incisors. ■ Lower lateral incisors and canines.

Chronological hypoplasia due to metabolic upset Chronological hypoplasia due to metabolic upset. Unlike the hereditary types of amelogenesis imperfecta, defects are linear and thought to correspond to a short period of amelogenesis disturbed by a concurrent severe illness

Syphilitic hypoplasia Congenital syphilis Hutchinson’s incisors & mulberry molars

Congenital syphilis; Hutchinson's teeth Congenital syphilis; Hutchinson's teeth. The characteristics are the notched incisal edge and the peg shape tapering from neck to tip.

Disturbances in the structure of teeth Disturbances of dentine This genetic disorder is characterised by defective dentine matrix production and two types have been described. Dentinogenesis imperfecta type 1 occurs in association with osteogenesis imperfecta, in which there is defective bone formation. It is very uncommon. Dentinogenesis imperfecta type 2 is the commonest form. It has the following features: ■ Both the permanent and primary dentition are affected. ■ The teeth have a normal shape on eruption but appear amber–brown or purple–blue in colour. ■ The enamel shears away from the poorly formed dentine which quickly wears away. ■ The pulps become obliterated with abnormal dentine.

Clinical features type I : deciduous severe than permanent teeth; type II: equally affected; type III: both dentitions affected. Gray to brownish violet or yellowish brown color, with translucent or opalescent hue. Enamel lost early through fracture, esp. on the incisal & occlusal surface, and dentin attrition rapidly. Caries rate is not increased.

Dentinogenesis imperfecta

Regional odontodysplasia Developmental Structural Abnormalities Involving Both Enamel and Dentin Regional odontodysplasia (odontodysplasia; odontogenic dysplasia; odontogenesis imperfecta; ghost teeth) One or several teeth in a localized area Maxi. > Mand.; both dentitions most in ant. area Delayed or total failure eruption Irregular appearance Defective mineralization

Radiographic features 1. Radiodensity ↓, “ghost appearance” 2. Large pulp, thin enamel & dentin On one side of the midline the deciduous incisors have poor root formation with thin radicular dentine and enamel. A poorly organised spotty calcification is present at the site of the permanent successors.

Odontogenesis Imperfecta Shell teeth Initial reported in the Brandywine population Normal thickness of enamel associated with extremely thin dentin and dramatically enlarged pulps (due to insufficient and defective dentin formation) Short roots.

Kaohsiung Medical University, Oral Pathology and image Diagnosis Dept.

ENDEMIC DENTAL FLUOROSIS Acceptable measures of fluorine in water according to hygienic standards is – 0,8-1,2 (1,5) mg/l. Fluorosis is the term given to changes in the enamel which are associated with excess ingestion of fluoride Fluorosis. Moderate effects from an area of endemic fluorosis. Irregular patchy discolouration.

Dental fluorosis Retention of the amelogenin protein in enamel structure → hypomineralized enamel → permanent hypomaturation → increased surface and subsurface porosity → alters light reflection and create white, chalky area

Dental fluorosis Critical period for clinical dental fluorosis is the 2nd and 3rd year of life, dose dependent Caries resistant

POSTERUPTIVE DEFECTS II. Lesions that occur after teeth have been erupted: 1. tooth wear: attrition, abrasion, wedge-shaped defect; 2. erosion; 3. necrosis of hard tooth tissues; 4. hyperesthesia; 5. trauma of teeth; 6. fluorosis;

Attrition Tooth to tooth contact during occlusion and mastication, some are physiologic Accelerated by: poor quality or absent enamel, premature contact, intraoral abrasives, erosion, grinding habits Incisal, occlusal and interproximal surfaces

Abrasion Pathologic loss of tooth structure or restoration secondary to the action of an external agent (ex. Toothbrush, hair grips, toothpicks, chewing tobacco, biting thread, dental flossing…) Toothbrush abrasion: horizontal buccal cervical notches of exposed radicular cementum and dentin with smooth surface. Greater on prominent teeth ( canines, premolars , and teeth adjacent to edentulous area) and side of the arch opposite to the dominant hand Demastication- when tooth wear is accelerated by chewing an abrasive substance between opposing teeth (both attrition and abrasion)

Abrasion

Abrasion Improper use of hair grips Long-term use of tobacco pipe

Abfraction Repeated tooth flexure caused by occlusal stresses (tensile stress) → concentrate at the cervical fulcrum → may produce disruption in the chemical bonds of enamel crystal →cracked enamel can be lost or removed by erosion or abrasion Wedge-shaped cervical defects, deep, narrow V-shaped, not allow toothbrush to contact base; if the defect, often affect a single tooth Almost exclusively on facial surface and more often in bruxism, higher in mandibular dentition

Abfraction

Erosion Chemical process, exposure to acidic foods or drinks, medications (chewable Vit. C, aspirin), involuntary regurgitation (ex. esophagitis, pregnancy), voluntary regurgitation (ex. psychologic problems, bulimia) Perimolysis- dental erosion from gastric secretion Facial surface of maxillary anteriors affected-dietary source Posterior teeth extensive loss of occlusal surface, and palatal surface concave dentin surrounded by an elevated enamel rim- regurgitation of gastric secretion 上顎前牙的腐蝕可能是食物因素而起, 而舌側及咬合面的腐蝕則可能是內生性的, 如胃液逆流而來。

concave dentin surrounded by an elevated enamel rim Erosion concave dentin surrounded by an elevated enamel rim

Erosion A bulimia patient

Treatment and prognosis of tooth wear Resolve pain and sensitivity Identify the cause of tooth structure loss Protection

ENVIRONMENTAL DISCOLORATION OF TEETH Extrinsic- surface accumulation of exogenous pigment Intrinsic-secondary to endogenous factors that result in discoloration of underlying dentin

Extrinsic stains Bacterial- Chromogenic bacteria, green, black-brown, orange coloration Frequently in children, labial surface of maxillary ant. in gingival third Iron- formation of ferric sulfide Tobacco Food and beverage- chlorophyll Gingival hemorrhage- Hb. breakdown to biliverdin Restorative material – ex. Amalgam Medications- iron, iodine, silver nitrate, chlorhexidine, stannous fluoride

Intrinsic stains Amelogenesis imperfecta Dentinogenesis imperfecta Dental fluorosis Erythropoietic porphyria – autosomatic recessive disorder of porphyrin metabolism, increased synthesis and excretion of porphyrins and their related precursors Porphyrin deposition in teeth, reddish-brown coloration, red fluorescence when exposed to a Wood’s UV light Present both in dentin and enamel in deciduous teeth, but only dentin affected in permanent teeth

Erythropoietic porphyria Hyperbilirubinemia

Intrinsic stains Hyperbilirubinemia- bilirubin, breakdown product of RBC, jaundice (yellow-green discoloration), erythroblastosis fetalis, biliary atresia Biliverdin deposition, green discoloration of teeth (chlorodontia) Ochronosis-alkaptonuria, blue-black discoloration Trauma- coronal discoloration, pulp necrosis Localized RBC breakdown

Intrinsic stains Medications- Tetracycline (bright yellow to dark brown), chlortetracycline (gray-brown), oxytetracycline (yellow) , minocycline hydrochloride Time of administration dose, duration Avoid from pregnancy up to 8 yrs of age

Minocycline hydrochloride Tx for Acne Blue-gray from incisal 3/4, to dark green or black in roots, also affect developed teeth Skin, nail, sclera, conjunctiva, thyroid, bone discoloration in susceptible individuals Stained alveolar bone

Treatment and prognosis Extrinsic stains- polishing Intrinsic stains- bleaching, bonded restoration, crowns

Uncomplicated crown fracture TRAUMA Uncomplicated crown fracture

Complicated crown fracture

Crown-root fracture Root fracture