Abnormalities of the Teeth

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• Abnormalities of the Teeth

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Environmental Effects on Tooth Structure
Development
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Environmental Effects on Tooth Structure
Development

• Visible environmental enamel defects can be
  classified into one of three patterns
• Enamel hypoplasia pits, grooves, or larger
  areas of missing enamel
• Diffuse opacities of enamel variations in
  translucency or normal thickness increased white
  opacity with no clear boundary with adjacent
  normal enamel
• Demarcated opacities of enamel show areas of
  decreased translucence, increased opacity, and a
  sharp boundary with adjacent enamel normal
  thickness

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Environmental Effects on Tooth Structure
Development

• Common pattern occurs as result of systemic
  influences (such as exanthematous fevers) which
  occur during the first two years of life
  horizontal rows of pits or diminished enamel on
  anterior teeth and first molars enamel loss is
  bilateral
• Similar pattern in cuspids, bicuspids, and second
  molars when the inciting event occurs at age 4-5

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Enamel Hypoplasia associated with exanthematous
fevers
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Turners Hypoplasia (1)

• Secondary to periapical inflammatory disease of
  the overlying deciduous tooth
• Enamel defects vary from focal areas of white,
  yellow or brown to extensive hypoplasia involving
  the entire crown.
• Most frequently affects permanent bicuspids
• Traumatic injury to deciduous teeth also causes
  Turners teeth (45 of children sustain injuries
  to primary teeth)

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Turners Hypoplasia (2)

• Trauma can displace the already formed hard tooth
  substance in relationship to the remaining soft
  tissue for root formation causing dilaceration (a
  bend in the tooth root)
• Severe trauma early in tooth development can
  cause disorganization of the bud resembling a
  complex odontoma. Severe trauma later on can
  lead to partial or total arrest of root formation.

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Turners Hypoplasia
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Turners Hypoplasia
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Hypoplasia Caused by Antineoplastic Therapy

• Degree and severity related to age, form of
  therapy (chemotherapy/radiotherapy) and dose
• Defects include hypodontia, microdontia,
  radicular hypoplasia, enamel hypoplasia and
  discolorations
• Radiotherapy effects more severe than
  chemotherapy alone but sometimes used together
• Dose of radiation as low as 0.72 Gy can cause
  mild defects in enamel/dentin
• Mandibular hypoplasia due to direct radiation,
  alveolar deficiency or pituitary effects.

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Hypoplasia Caused by Antineoplastic Therapy
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Dental Fluorosis

• Critical period is age 2-3, if fluoride levels
  greater than 1 part per million are ingested
• Fluoride comes from several sources besides
  water adult-strength fluoride toothpastes,
  fluoride supplements, infant foods, soft drinks,
  and fruit juices
• Severity is dose dependent (higher intakes during
  critical periods associated with more severe
  fluorosis)

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Dental Fluorosis
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Syphilitic Hypoplasia

• Mulberry molars constricted occlusal tables
  with disorganized surface anatomy resembling
  surface of a mulberry
• Anterior teeth called Hutchinsons incisors, have
  crowns shaped like straight-edge screwdrivers
  incisal taper notch
• Treatment - Most are cosmetic problems treatment
  includes acid-etched composite resin
  restorations, labial veneers, and full crowns

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Syphilitic Hypoplasia
Moons (mulberry) molars
Hutchinsons incisors
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Postdevelopmental Loss of Tooth Structure
Attrition

• Loss of tooth structure caused by tooth-to-tooth
  contact during occlusion and mastication.
• Pathologic when it affects appearance and
  function.
• Process can be accelerated by poor quality or
  absent enamel, premature edge-to-edge occlusion,
  intraoral abrasives, erosion, and grinding
  habits.

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Attrition

• Can occur in deciduous and permanent dentitions
• Most frequently, incisal and occlusal surfaces
  involved
• Large flat wear facets found in relationship
  corresponding to pattern of occlusion
• Interproximal contact points also affected
• Over time, interproximal loss can result in
  shortening of arch length

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Postdevelopmental Loss of Tooth Structure
Attrition
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Postdevelopmental Loss of Tooth Structure
Abrasion

• Pathologic loss of tooth structure secondary to
  the action of external agent
• Most common source is tooth brushing with
  abrasive toothpaste and horizontal strokes.
• Also pencils, toothpicks, pipe stems, bobby pins,
  chewing tobacco, biting thread, inappropriate use
  of dental floss

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Abrasion

• Variety of patterns, depending on the cause
• Toothbrush abrasion presents as horizontal
  cervical notches on buccal surface of exposed
  radicular cementum and dentin degree of loss
  greatest on prominent teeth
• Thread-biting, pipe stem, bobby pins etc.,
  produce rounded or V-shaped notches in incisal
  edges of anterior teeth
• Dental floss, toothpicks result in loss of
  interproximal radicular cementum and dentin

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Abrasion
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Abrasion
Abrasion from partial clasp
Abrasion from improper flossing
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Postdevelopmental Loss of Tooth Structure
Erosion

• Loss of tooth structure by chemical reaction, not
  that associated with bacteria (caries)
• Secondary to presence of acid or chelating agent
• Source can be dietary (e.g., vinegar, lemons),
  internal (gastric secretions perimolysis), or
  external (e.g., acids, industrial, atmosphere)
• If it is not abrasion or attrition, it must be
  erosion

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Erosion

• Commonly affects facial surface of maxillary
  anteriors and appears as shallow spoon-shaped
  depressions in cervical portion of the crown
• Posterior teeth exhibit loss of occlusal surface,
  where dentin is destroyed more rapidly than
  enamel, resulting in concave depression of dentin
  surrounded by elevated rim of enamel
• Erosion limited to facial surfaces of maxillary
  anterior dentition is usually associated with
  dietary acid.

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Erosion

• Tooth loss confined to incisal portions of
  anterior dentition of both arches indicates
  environmental source.
• Erosion on palatal surfaces of maxillary anterior
  teeth and occlusal surfaces of posterior teeth of
  both dentitions probably caused by regurgitation
  of gastric secretions.

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Erosion

• Fizzy Drinks Are Major Cause of Teen Tooth
  Erosion Thu Mar 11, 706 PM ET LONDON (Reuters)
  - Fizzy drinks are the major cause of tooth
  erosion in British teenagers but many parents are
  not aware of the problem, researchers said on
  Friday.   
• The sodas and pop drunk by up to 92 percent of UK
  14-year-olds wear away the enamel protective
  coating on teeth. Dental erosion weakens teeth
  and can cause thinning or chipping of the tooth
  edges.
• "This research identifies fizzy drink as by far
  the biggest factor in causing dental erosion
  among teenagers," said Dr Peter Rock, of
  Birmingham University.
• "Drinking fizzy drinks only once a day was found
  to significantly increase a child's chances of
  suffering dental erosion," he added.
• Drinking four or more glasses of fizzy drinks a
  day raises a 12-year-old's chances of suffering
  from tooth erosion by 252 percent. Heavy
  consumption in 14-year-olds increased the risk to
  513 percent, according to research published in
  The British Dental Journal.
• Unlike tooth decay, which results from high
  levels of sugar, erosion is caused by acidic
  substances in the drinks. Even diet versions are
  harmful.
• Drinking milk and water, instead, reduces the
  risk.
• "Erosion is a growing problem among British
  teenagers, yet many parents don't understand the
  difference between decay and erosion," said
  Professor Liz Kay of the British Dental
  Association.
• "Parents need to understand...it is the acidity
  of certain products that cause erosion," she
  added in a statement.

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Erosion
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Postdevelopmental Loss of Tooth Structure
Abfraction

• Loss of tooth structure resulting from repeated
  tooth (enamel dentin) flexure produced by
  occlusal stresses
• Disruption of chemical bonds at cervical fulcrum
  leads to cracked enamel that can be vulnerable to
  abrasion and erosion

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Abfraction

• Wedge-shaped defects limited to cervical area
• Deep, narrow, V-shaped
• Sometimes single tooth or subgingival
• More common in mandibular dentition and among
  those with bruxism

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Abfraction
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Treatment of Postdevelopmental Loss of Tooth
Structure

• Early diagnosis and intervention to restrict
  severity of tooth loss
• Patient education
• Mouth guards
• Limit (redirect) tooth brushing flossing
• Replacement of lost posterior teeth and avoidance
  of edge-to-edge occlusion
• Composite resins, veneers, onlays, full crowns

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Internal External Resorption

• Internal resorption is caused by cells located in
  dental pulp. Rare, usually follows injury to
  pulpal tissues.
• External resorption is caused by cells in the
  periodontal ligament. Most patients are likely
  to have root resorption on one or more teeth.

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Internal Resorption

• Internal resorption presents as a uniform,
  well-circumscribed symmetrical radiolucent
  enlargement of pulp chamber. When it affects the
  coronal pulp, crown can display pink
  discoloration (pink tooth of Mummery)

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External resorption

• External resorption presents with a moth-eaten
  loss of root structure in which radiolucency is
  less well-defined and demonstrates variations in
  density. Most cases of external resorption
  involve apical or mid-portions of root

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Internal External Resorption

• Cervical pattern of external resorption is often
  rapid (invasive resorption)
• Multiple idiopathic root resorption involves
  several teeth, underlying cause not obvious
• Treatment involves the removal of all soft tissue
  from sites of dental destruction. For external
  resorption, determine if an accelerating factor
  is present, and eliminate it.

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Internal External Resorption
External Resorption
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Internal resorption
Internal resorption
External resorption-- embedded tooth
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Environmental Discoloration of Teeth
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Environmental Discoloration of Teeth Extrinsic

• Arise from surface accumulation of exogenous
  pigment
• Bacterial stains occur most frequently in
  children
• Excessive use of tobacco, tea, coffee
• Foods that contain abundant chlorophyll
• Restorative materials, especially amalgam
• Medications
• Stannous fluoride and chlorhexidine
• Extrinsic stains can be removed by polishing with
  fine pumice, (sometimes with added 3 hydrogen
  peroxide) recurrence is likely unless the
  associated cause is altered

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Environmental Discoloration of Teeth Extrinsic
Amalgam stain
Tobacco stain
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Environmental Discoloration of Teeth Intrinsic

• Secondary to endogenous factors that discolor
  underlying dentin
• Congenital erythropoietic porphyria (Günthers
  disease) is an AR disorder of metabolism that
  results in increased synthesis and excretion of
  porphyrins
• Hyperbilirubinemia due to jaundice,
  erythroblastosis fetalis (hemolytic anemia of
  newborns secondary to blood incompatibility,
  usually Rh factor), biliary atresia (sclerosing
  process of the biliary tree), and chlorodontia
  (green discoloration).

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Environmental Discoloration of Teeth Intrinsic

• Localized red blood cell destruction (pink
  discoloration arising from hemoglobin breakdown
  within necrotic pulp tissue when blood has
  accumulated in the head)
• Lepromatous leprosy (pink discoloration secondary
  to infection-related necrosis and the rupture of
  numerous small blood vessels within the pulp
• Medications (tetracycline)
• Intrinsic stains are difficult to treat.
  Possible treatments include full crowns, external
  bleaching of vital teeth, internal bleaching of
  nonvital teeth, bonded restorations, composite
  build-ups, and laminate veneer crowns.

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Intrinsic Coloration of Teeth
Porphyria
Hyperbilirubinemia
Tetracycline Stain
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Localized Disturbances in Eruption
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Localized Disturbances in Eruption

• Eruption the continuous process of movement of
  a tooth from developmental location to functional
  location
• Impacted teeth that cease to erupt due to
  physical obstruction
• Embedded teeth that cease to erupt due to lack
  of eruptive force
• Ankylosis teeth that cease to erupt due to
  anatomic fusion of tooth with alveolar bone

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Localized Disturbances in Eruption

• Primary impaction of deciduous teeth is extremely
  rare. Most commonly involves second molars often
  due to ankylosis.
• Primary impaction of permanent teeth most
  frequently affects third molars. Lack of eruption
  is most often related to crowding and
  insufficient maxillofacial development.
• Impacted teeth are frequently diverted or
  angulated, eventually losing their potential to
  erupt mesioangular, distoangular, vertical,
  horizontal and inverted

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Localized Disturbances in Eruption

• Treatment includes long-term observation,
  orthodontic-assisted eruption, transplantation,
  or surgical removal
• Risks associated with both intervention and
  nonintervention
• Surgical removal of impacted teeth is the
  procedure most frequently performed by OMFS

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Localized Disturbances in Eruption

• Ankylosis cessation of eruption after emergence
• Usually develops between ages 7-18 peak 8-9
  prevalence est. 1.3-8.9
• Fails to respond to orthodontic therapy
• Failure to treat can result in tilting, carious
  destruction, and periodontal disease
• When successor tooth present, best treated with
  extraction and space maintenance

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Localized Disturbances in Eruption
Primary tooth impaction
Mesioangular impaction
Ankylosis
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Developmental Alterations of the Teeth
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Developmental Alterations in the Number of Teeth

• Anodontia total lack of tooth development.
  Rare most cases occur in hereditary hypohidrotic
  ectodermal dysplasia
• Hypodontia lack of development of one or more
  teeth. Uncommon in deciduous teeth, usually
  involves mandibular incisors. More common in
  permanent teeth, third molars most affected.
  More frequent in females than males
• Oligodontia lack of development of six or more
  teeth

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Developmental Alterations in the Number of Teeth

• Hyperdontia development of increased number of
  teeth. Additional teeth are supernumerary.
  Prevalence 1-3. More common in males and
  usually develops by age 20.
• Maxilla is most common site (90) for single
  tooth hyperdontia, especially incisor region
  (mesiodens)
• Most single supernumerary teeth are unilateral.
  Nearly 75 of supernumerary teeth in anterior
  maxilla fail to erupt
• Non-syndromic multiple supernumerary teeth occur
  mostly in mandible.

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Hypodontia (oligodontia)

• Example of pedigree

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Hypodontia in Ectodermal Dysplasia