Anatomy - Outcome 14 Flashcards
Initiation
This process includes the dental lamina and bud stages, and affects the presence of absense of tooth bud.
Proliferation
Occurs during the bud, cap and bell stages, and influences the general size and proportions of the tooth germ.
Histodifferentiation
This process takes place from the advanced cap stage through the bell stage, and basically involves the formation of potential enamel and dentin-forming cells
Morphodifferentiation
The shape and size of the tooth are determined in this process, which happens during the budy, cap and bell stages. Thus a disturbance in morphodifferentiation may inffluence the size and shape of a tooth but have no effect on the enamel and dentin-forming process.
Apposition
The process is active during the bell stage, through the completion of the root, and involves the regular laying down of the enamel and dentin.
Maturation
Dental tissues fully mineralize
Most dental anomalies are caused by…
hereditary and congenital factors, developmental, or metabolic disturbances
Important factors influencing the final form of the anomaly, as well as which teeth are affected
The stages of development along with the length of the effect
Is permanent or primay teeth more prone to abnormality?
Permanent dentition is much more prone to abnormality than deciduous teeth. This is partially explained by the position of the permanent tooth bud on the dental lamina when compared to the primary tooth bud
Tooth anomalies may appear as variations in…
-number
-size
-shape (form)
-structure (calcification and apposition
Abnormal Number of Teeth - Reason
The presence of an abnormal number of teeth, either more or less than usual, is almost always the result of some type of disturbance during the initiation process (dental lamina and budy stage) of teooth develipment. The disturbance is most often hereditary in nature.
Anodontia
-complete absence of teeth or absense of a single tooth
-hereditary, hormonal, disease, radiation
-complete absence very rare
Hyperdontia
-supernumerary (extra tooth)
-extra bud from dental lamina
-does not resemble normal tooth
-mesiodens
-4th molar
-hereditary/syndromes
Abnormal Size of Teeth
-Normally the teeth of an individual vary in size directly with their general face and body size. Therefore, large, or small teeth, when found in this context, are not considered to be abnormal
- very rare for all the teeth to be abnormal in size
- Anomaly is usally limited to a single tooth, or a few teeth of the same type
- is thought to be the result of a disturbance during morphodifferentiation in the bell stage, with genetic etiologoy
Macrodontia (Gigantism)
-abnormal increase in tooth size
-one or more teeth
True Macrodontia
-rare
-all teeth
-pitutiary gigantism
False Macrodontia
-incomplete tooth splitting
-teeth fusing together
Microdontia (Dwarfism)
-abnormal decease in tooth size
-hereditary
-bilateral
Complete Microdontia
-pituitary dwarfism
-all teeth, rare
Isolated Microdontia
-peg laterals (maxillary lateral incisors)
-cancer treatment during tooth development
Abnormal Shape of Teeth
-abnormal crown and root shapes and contours is normally involved with disturbances during the morpho differentiation and apposistional stages of tooth development
Dens in Dente
-tooth within a tooth
-enamel and dentin vaginate inward to the pulp
-common in maxillary laterals and central incisors
-may require endodontics
Dilaceration
-sharp bend in a root or crown
-interference with eruption path
-crowding, trauma, orthodontics
-common 3rd molars
-endo and exo concerns
Flexion
-same cause as dilaceration
-only involves root
Gemination
-single tooth bud attemps to split in two
-imcomplete division
-mandibular and maxillary incisors
-clinically difficult to distinguish from fusion
-complete separation (twinning) is possible
-normal complement of teeth or one extra tooth
Fusion
- two tooth buds attempt to join
-incisors common
-one less tooth clincally
-radiographically two pulps
Concrescense
- union of 2 roots by cementum
-due to crowding and resorption of bone between roots
Enamel Pearl
-pearl-like deposits of enamel at the furcation of molars
-1-2 mm in size
-chronic periodontal infection
Hypercementosis
-excessive deposition of secondary cementum on roots
-trauma
-post eruption
-infection
-extraction difficult
Abnormal Calcification and Apposition – Disturbances in the Formation (Structure) of Teeth
This group of anomalies is the result of disturbances that affect enamel and dentin formation during the histodifferentiation and appositional stages. The resultant condition is dependent upon the severity of the disturbance, the stage of matrix or calcification affected, as well as the length of the disturbance
Enamel Hypoplasia
Incomplete or defective formation of enamel matrix on primary and secondary teeth.
Fever-Related Enamel Hypoplasia
-horizontal white lines, pits, or grooves
-lack of enamel
Amelogenesis Imperfecta
-hereditary cause
-defect enamel formation or lack of calcification
-various types and severity
Dental Fluorosis
-ingesion of excessive fluoride during tooth development
-bilateral
-chalky white to brown
Turner’s Teeth
Trauma or infection to primary tooth
-abscess affects permanent tooth bud (germ)
-white spot to enamel deficit
Hutchinson’s Incisors
-congenital syphillis
-affected incisors have incisal notches
-affected molars have small supernumerary lobes resembling a mulberry/raspberry (mulberry molars)
Hereditary Dentinogenesis Imperfecta
-hereditary development involving abnormal dentin developmen
-primary more than permanent
-no underlying support
-amber-grey brown
-fraction and sever attrition
-obliterates the pulp
Tetracycline Staining
-intrinsic stainig
-mom or child taking antibiotic
-band-like grey to green discoloration
-no functional side effect
An odontoma is really not an anomaly of shape, but rather a benign tumor. An odontoma is a growth of calcified dental tissues, involving structures of both ectodermal (enamel) and mesodermal (dentin, cementum, and pulp) origin. There are two basic types, both of which are thought to result from developmental disturbances of the dental lamina by trauma or infection
Complex Odontoma
This growth consists of calcified dental tissues and may be attached to a normal tooth, or located separately in the alveolar bone. It does not exhibit any definite dental form
Compound Odontoma
This type of odontoma also consists of the various calcified tissues of a tooth, but in comparing it to the “complex” type, these tissues are arranged in the shape of a recognizable tooth form. There may be one or more of these tooth forms, sometimes with almost perfect similarity to a normal tooth, and sometimes resembling more rudimentary dental forms
Attrition
-wearing down and loss of occlusal and/or incisal tooth structure due to frictional contact
-flattening of tooth
-grinding, occlusion porcelain restorations
Abrasion
-mechanical wearing away of tooth
-toothbrush - high pressure, med to hard bristles
-recession of gingiva
Abfraction
-appears as abrasion
-“v”-notches in dentin with recession
-shear and tensile stresses at CEJ (clenching)
-distruption of the bond between dentin and enamel
Erosion
-chemical wearing away/dissolving of enamel
-lemon sucking, cocaine, bulimia
-apple juice, carbonated beverages, sports beverages
Oral Facial Piercings
-chipped teeth, broken teeth, and infection at the site of the piercing
