Anatomy - Week 12.2 PP Flashcards
Tooth Anomalies - Dental Assistant Role with them
- Recognition of anomaly
-Patient education
-Treatment considerations
Types of Developmental Disorders
-Inherited disorders (genetic) are different from developmental disorders because they are caused by an abnormal gene
*a congenital disorder is one that is present at birth
*either inherited or developmental; however, exact cause of most congenital abnormatilies is un known
Genetic Factors
Malformations that are often the result of genetic factors such as chromosoal abnormalities
Environmental factors
Called teratogens; include infections, drugs, and exposure to radiation
Distrubances in Jaw Development - occur during development of the jaw
-Macrognathia - abnormally large jaw
Micrognathia - abnormally small jaw
Exostoses - a benign bony overgrowth projecting outward from the surface of a bone (usually on maxillary)
Torus palatinus - a bony overgrowth at the midline of the hard palate
Torus mandibularis - a bony overgrowth on the lingual surface of the mandible
Disturbances in Lip, Palate,
and Tongue Development
Cleft lip - results when the maxillary and medial nasal processes fail to fuse
Cleft palate - results when palatal shelves fail to fuse with primary palate
Cleft uvula - the mildest form of cleft palate
Ankyloglossia - often called tongue-tie; results in a short lingual frenum that extends to the apex of the tongue
Tooth Anomalies
- can happen during differnt stages of development
- length of effect
- heriditary or environmental cause
- more often in permanent dentition
Etiology of Anomalies
Stages of Development
- initiation
- Proliferation
- Histo-differentation - difference of cell type
- Morpho-differentiation - difference of shape
- Apposition
- Maturation
Abnormal Number of Teeth
-Initiation stage of development
- lack of initation within the dental lamina
*absence of a single tooth or an entire dentition
-Associated with… (during prego)
*Ectodermal dysplasia
*Endocrine dysfunction
*Systemic disease
*Radiation
Anodontia (Hypodontia)
-Partial or complete abesense of teeth
-Commonly include:
*permanent third molars
*maxillary lateral insicors
*Mandibular second premolarrs
Hyperdontia
-Supernumary tooth or teeth
-Commonly found:
*Between permanent maxillary icisors
*Distal to third molars
-Etiology:
*Hereditary
- more genetically common than Hypodontia
Mesiodens
small extra central incisor
erupts between two central incisors
Abnormal Size
-Bud stage of the development (proliferation stage)
- abnormal proliferation of the tooth bud can cause a single tooth or multipe teeth or an entire dentition to be larger or smaller than usual
- generally genetic with partial
- endocrine dysfunction associated with complete (during prego)
Macrodontia
-abnormal increase in tooth size
- childhood hyperpituitartism (gigantism) can cause
Microdontia
-Complete miccrodontia - extremely RARE!
*all teeth small
*associated with hypopituitarism or Down’s Syndrom
- True Partial Microdontia
*heritidary factors involved
*commonlly affects the permanent maxillary lateral insicors and permanent third molars
Abnormal Shape
- later stages of tooth development (/Aposition- Cap-Maturation)
- Proliferation of Morphodiffrentiation process
- Can pressent as abnormal crown or root shape
Dens in Dente
-Cap stage
-Enamel organ invaginates into the dental papillae
-Commonly affects permanent lateral incisor
-Etiology-Hereditary factors
Gemination
-Cap Stage (Maturation)
-The tooth germ tries to divide but develops a large single-rooted tooth with one pulp cavity and “twinning” in the crown of anterior teeth
-**The correct number of teeth will be present **
-Etiology - Hereditary
-an unsuccessful attempt is indicated by an incisal notch
-sometimes looks like just a notch, however, when you take an Xray it will become clear
Fusion
-Cap Stage
-Union of two adjacet tooth germs
-Results in a large tooth with two pulp cavities
-One fewer tooth in the dentition
-common on anteriors in primary dentition
-Etiology - Presssssuuuree!! Either during pregancy, during fetal growth, or right at birth
Tubercle
-Cap Stage
-Small rounded enamel extension
-commonly found on posterior occlusal surfaces or anterior lingual surfaces
Etiology - Trauma, pressure, or metabolic disease.. affecting the enamel organ
Enamel Pearl
-Apposition and Maturation stage
-Sphere of enamel root - almost perfectly round
-Etiology - displacement of ameloblasts to root surface
Hypercementosis
-refers to excess deposition of cementum on the root surfaces
-a variety of local and systemic factors have been associated: trauma, inflammation, supraeruption, pituitary gigantism, arthritis, calcinosis, Paget’s disease, rheumatic fever, and goiter.
- Occurs predominately in adults and an increased frequency is seen with increasing age
- may cause concrescense
Concrescence
- Apposition and Maturation Stage
- Union of the root structure of two or more teeth
by cementum - Commonly affects the permanent maxillary molars
- Etiology - traumatic injury or crowding of the
teeth
Root Formation
Dilaceration - results in a distorted root or severe crown angulation (caused by injury or pressure during tooth development)
- Flexion - a deviation or bend restricted just to the root
- Accessory roots - due to trauma, pressure or metabolic disease that effects HERS (Hertwig’s epithelial root sheath) during root developement
Structural Anomalies
Resulting from disturbances in enamel and dentin
formation
- Apposition and Maturation Stages
- Enamel or dentin dysplasia
Enamel Dysplasia
-Results from a reduction in the quantity of the enamel matrix
- Teeth appear with pitting and intrinsic colour changes in enamel
Amelogeneis Imperfecta
- Type of enamel hypoplasia/dysplasia
- Hereditary etiology
- Can affect all teeth of both the primary and permanent dentitions
- Teeth have very thin enamel that chips off or have no enamel at all – crowns are thus yellow
- Varies in severity
- Hereditary enamel hypoplasia is a type of amelogenesis imperfecta that is characterized by teeth with crowns that are hard and glossy, yellow, and cone-shaped or cylindrical
Dental Fluorisis
- Dental fluorosis is a change in the appearance of the tooth’s enamel.
- These changes can vary from barely noticeable white spots in mild forms to staining and pitting in the more severe forms (enamel will be severely altered)
- Dental fluorosis only occurs when younger children consume too much fluoride from any
source over long periods when teeth are developing under the gums
Turner’s Teeth
- Hypoplasia of the enamel involving a single permanent tooth.
- If found on a canine or a premolar, the most likely cause is an infection that was present when the primary tooth was still in the mouth.
- If found in the anterior area of the mouth, the most likely cause is a traumatic injury to a primary tooth
- occurs during formation of enamel
Congenital Syphilis
- Hutchinson’s Incisors
◦ Abnormally shaped permanent front teeth (incisors)
◦ Usually associated with congenital syphilis (treponema palladium) - Mulberry Molars
◦ a first molar tooth whose occlusal surface is pitted due to congenital syphilis with nodules replacing the cusps
Dentin Dysplasia
- faulty development of dentin
Dentinogenesis Imperfecta
Hereditary basis
- results in blue-gray or brown teeth with an opalescent sheen
-enamel appears as usual but chips off due to lack of support from the abnormal underlying dentin - results in severe attitrion
- teeth that have dentinogeneisis imperfecta are opalescent and have an almost amber colour
Tetracycline Staining
- incorporation into dentinal tissue that is calcifying at the time of administration
- the antibiotic become chemically bound to the dentin for the ife of the tooth and because of the transparency of enamel, it is visible
- Permanent discoloration varies from yellow or gray to brown depending on the dose or the type of the drug received in ralation to body weight
Odontoma
Etiology is unknown
- tumor
-local trauma
-◦ Inflammatory and/or infectious processes
◦ Dental lamina remnants
◦ Hereditary anomalies
◦ Odontoblastic hyperactivity
◦ Alterations of the genetic component responsible for
controlling dental development
-usuaslly asymptomatic
-often found when taking xrays
Complex Odontomas
When the calcified dental tissues are simply arranged in an rregular mass bearing no morphologic similarity to rudimentary teeth (tumo)
Compound odontomas
- Composed of all odontogenic tissues in an orderly pattern that results in many teethlike structures but without morphologic resemblance to normal teeth
Ameloblastoma
◦ A tumor composed of remnants of the dental lamina
Degeneration Changes - Attrition
- Wearing down of incisal/occlusal
- Frictional contact
- Grinding/occlusion
Degeneration Changes - Abrasion
- Mechanical wearing away of tooth
- Buccal/lingual surface
- Recession
- Toothbrush abrasion
Degeneration Changes - Bruxism
◦ Oral habit consisting of involuntary gnashing, grinding, and clenching of the teeth in
movements other than chewing
◦ Usually occurs during sleep and is commonly associated with stress or tension
Degeneration Changes - Abfraction
- V – shaped notches in dentin
- Confused with abrasion
- Shear and tensile stresses
- CEJ- slight flexion
Degeneration Changes - Erosion
-Chemical wearing away
-Disolving of enamel
- bulemia
-carbonated beverages
-lemons
Orofacial piercings
◦ Have become popular among some segments of the population
◦ Dental complications include chipped and broken teeth and serious infections at the sites
of piercings
◦ Infection can spread throughout the head and neck area, with serious results
Premature eruption
◦ In premature eruption, teeth are present at birth (natal teeth)
◦ Neonatal teeth are those that erupt within the first 30 days of life
Ankylosis
- in decidous teeth affected by ankylosis, bone has fused to cementum and dentin, preventing exfoliation
Impaction
Occurs when any tooth remains unerupted in the jaw beyond the time at which it should normally erupt
