lecture 8+9 Abnormalities of Teeth

lecture 8+9 Abnormalities of Teeth

1. 3

   • Developmental Alterations in the Shape of Teeth
     • • gemination
         • single enlarged tooth or joined (double) tooth in which the tooth count is normal when the anomalous tooth is counted as one
           • both deciduous>> incisors and canines>> differentiated by assessing the number of teeth in the dentition
             • A bifid crown with two completely separated roots, or joined crowns blend in one enlarged root with a single canal
           • maxilla >>
             • if
               • double teeth - separate pulps<< hemisection without root canal therapy
                 • double teeth - one pulp << endodontic therapy is necessary if sectioning is considered
       • Fusion
         • single enlarged tooth or joined (double) tooth in which the tooth count reveals a missing tooth when the anomalous tooth is counted as one
           • mandible
       • concrescence
         • union of two teeth by cementum without confluence of the dentin (It is frequent in maxillary 2nd and 3rd molars because their routes are so close to each other).
         • • developmental / post-inflammatory
             • posterior and maxillary regions
               • 2nd-3rd molars
             • requires no therapy unless it interferes with eruption<< surgical removal
     • Accessory Cusps
       • Cusp of Carabelli
         • palatal surface of the mesiolingual cusp of a maxillary molars (1sr>2nd>3rd)
       • Talon Cusp
         • anterior tooth and>1/2 distance from the cementoenamel junction to the incisal edge
         • eagle’s talon
           • lingual surface of the affected tooth and forms a three-pronged pattern
         • permanent maxillary lateral/ central incisor>> mandibular incisors and maxillary canines
         • max should be removed
       • Dens Evaginatus (Leong premolar)
         • in the central groove or lingual ridge of the buccal cusp
           • PM >>> M
           • MAND>>
           • BILATERAL
           • deciduous
         • Radiographically
           • tuberculated appearance, and often a pulpal extension is seen in the cusp.
         • may result in
           • dilaceration, displacement
           • rotation of the tooth
           • tilting
       • Dens Invaginatus
         • deep surface invagination of the crown or root that is lined by enamel
     • Ectopic Enamel
       • enamel in unusual locations, mainly the tooth root
         • most widely known are enamel pearls
       • • enamel pearls.
           • the maxillary permanent molars >> mand molar
             • place
               • root furcation
               • CEJ
               • Mature internal enamel pearls
                 • well-defined circular areas of radiodensity, extending from the dentinoenamel junction (DEJ) into the underlying coronal dentin.
             • normal periodontal attachment with connective tissue, and a hemidesmosomal junction
               • less resistant
                 • associated with extensive bone loss and abscess formation
         • Cervical Enamel Extensions
           • • buccal surface of the root overlying the bifurcation
               • Mandibular molars are >> maxillary molars
                 • extracted teeth 20% to 50% of molars are affected.
                   • • Because connective tissue cannot attach to enamel
                     • localized loss of periodontal attachment with furcation involvement.
             • associated with the development of inflammatory cysts identical to inflammatory periapical cysts.
               • along the buccal surface over the bifurcation and most appropriately
                 • called buccal bifurcation cysts
       • Treatment and Prognosis
         • enamel pearls
           • no treatment
             • meticulous oral hygiene should be maintained.
           • exposed due to periodontal pocket formation and removal is contemplated, then the clinician must remember that lesion occasionally contains vital pulp tissue.
         • cervical enamel extensions<< surgical therapy
     • Taurodontism
       • • enlargement of the body and pulp chamber of a multirooted tooth, with apical displacement of the pulpal floor and bifurcation of the roots
           • molar teeth of cud-chewing animals
           • e rectangular and exhibit pulp chambers with a dramatically increased apico-occlusal height and a bifurcation close to the apex.
           • highly variable (0.5% to 46%) normal >> patho
         • 3rd>2nd>1st
       • The degree of taurodontism has been classified into according to the degree of apical displacement of the pulpal floor.
         • mild (hypotaurodontism), moderate (mesotaurodontism), and severe (hypertaurodontism)
       • increased frequency of taurodontism with
         • hypodontia, cleft lip, and cleft palate.
     • • Hypercementosis
         • Non-neoplastic / excessive cementum
           • factors
             • local
               • Adjacent inflammation (e.g pulpal, periapical, periodontal)// Unopposed teeth (lack of function), (e.g impacted, embedded, without antagonist) // occlusal trauma (hyperfunction)
                 • Most common cause, periapical periodontitis
             • systemic
               • Acromegaly and pituitary gigantism • Arthritis • Calcinosis • Paget’s disease of bone, not common in our country. • Rheumatic fever • Thyroid goiter • Gardner syndrome • Vitamin A deficiency (possibly)
                 • Paget’s disease of bone ass 100% with Hypercementosis
           • mandibular molars >>
           • adulthood, and frequency increases with age >>
           • hypercementosis require no treatment. Unless they need RCT for pulpal necrosis
         • radiology
           • thickening or blunting of the root.
             • no periapical inflammation, the enlarged root is surrounded by the radiolucent periodontal ligament space and adjacent intact lamina dura
             • periapical periodontitis : lamina-dura will be resorbed so PDL and lamina dura will be absent.
         • histology
           • periphery of the root << excessive amount of cementum
             • The excessive cementum may be hypocellular or cellular
               • concentric layers and may be applied over the entire root / apical portion
                 • light microscopy, distinguishing between dentin and cementum<<< difficult ~ section with polarized light helps to discriminate between the two different layers
       • Dilaceration
         • angulation or bend
           • after an injury that displaces the calcified portion of the tooth germ,
             • follows avulsion (tooth comes out of the socket) or intrusion (tooth goes inside the bone)
               • anterior dentition >>
         • radiographically obvious if the bend occurs in a mesial or distal direction. Roots that bend facially or lingually may be more difficult to detect
       • Supernumerary Roots
         • increased number of roots
           • 3rd perm >> PM mand

2. 2

   • Developmental alterations in the size of teeth
     • Microdontia
       • maxillary lateral incisors and the third molars are among the most frequent teeth to be congenitally missing.
         • finding in: Down syndrome, pituitary dwarfism, and in a small number of rare hereditary disorders .
     • Macrodontia
       • association with: pituitary gigantism, pineal hyperplasia with hyperinsulinism
         • Isolated macrodontia incisors or canines >>second premolars+ third molar

3. 1

   • Developmental Alterations in the Number of Teeth
     • lack of development __ teeth.
       • 1<
         • Hypodontia
         • 6+
           • Oligodontia
       • all teeth missing
         • Anodontia
     • Hypodontia
       • • common in permanent teeth
           • 3% to 10% perm - third molars is excluded
           • 20% - third molars included
           • third molars >> second premolars MAND>> lateral incisor MAX
         • uncommon in deciduous teeth
           • 90% are maxillary lateral incisors and mandibular incisors
         • female- 1.5 : 1
         • associated with
           • • microdontia
             • reduced alveolar development
             • increased freeway space
             • anterior malocclusion
             • retained primary teeth
           • Sequelae
             • • Abnormal spacing of teeth
               • Delayed tooth formation
               • Delayed tooth formation
               • Late permanent tooth eruption
               • Altered dimension of the associated gnathic regions
         • management - severity
           • No treatment = single missing tooth// Prosthetic replacement = multiple teeth are absent.//orthodontic therapy helpful
         • Hereditary Hypohidrotic Ectodermal Dysplasia
           • ectodermal dysplasia. - Thin, sparse hair. - Short stature and low weight. - Sparse light-colored eyebrows. - Thin and brittle nails. - Absence of all teeth or some teeth. - Episodes of high fever because they don’t have sweat glands. - Intolerance to heat, and lack of sweat. - Light intolerance. - Dry and rough skin because of the absence of secretions (sweat).
     • Hyperdontia
       • • 1>> 2>> 3+more less than 1% of cases
           • maxillary incisor region (Mesiodens)= single tooth
           • non-syndromic multiple supernumerary teeth occur most frequently in the mandible.
             • premolar > molar > anterior .
         • eruption= degree of space available: 75% of supernumerary teeth in the anterior maxilla fail to erupt
         • macrodontia //2:1 male //first two decades of life
         • depending on their location:
           • Mesiodens: in the maxillary anterior region
           • Distomolar or distodens: fourth molar
           • Paramolar: a posterior lingually or buccally to a molar tooth
         • divided into:
           • Supplemental (normal size and shape)
           • Rudimentary (abnormal shape and smaller size)
         • we could see
           • dental transposition :erupt into an inappropriate position
           • natal and neonatal teeth may represent predeciduous supernumerary teeth, but most are prematurely
         • notes
           • Complicationsof anterior supernumerary >>>> posterior regions
           • Consequences of late therapy may include:
             • Delayed eruption
             • Resorption of adjacent teeth
             • Displacement
             • Infections
             • cysts and tumors.

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