Dental Anomalies Flashcards
what is an anomaly?
a deviation from normal or average that can result in the absence, excess or deformity of body parts
what are the 4 stages of tooth development?
initiation
bud
cap
bell
what happens during the initiation stage of tooth development?
-begins approximately 6 weeks in utero
- basal cells of the oral epithelium proliferate
- dental lamina becomes distinctive from the oral epithelium and connects the developing tooth bud to the oral epithelium
what happens during the bud stage of tooth development?
- epithelial cells proliferate into the ectomesenchyme of the jaw
- cells are not clearly arranged yet
- the actual tooth bud is a group of cells at the periphery of the dental lamina
what happens during the cap stage of tooth development?
- a small group of ectomesenchymal cells form the dental papilla
- tooth bud (enamel organ) grows around the dental papilla and takes on a cap shape
- ecentually tooth bud forms enamel and dental papilla forms dentin and pulp
what happens during the bell stage of tooth development?
- enamel organ is bell shaped
- morphodifferentiation takes place
- dental lamina disintegrates, separating tooth from oral epithelium
- during the late bell stage hard tissues develop (enamel and dentin)
what is anodontia and what are the different types?
the absence of teeth due to congenital factors inhibiting one or more tooth buds from forming
total anodontia, partial anodontia/hypodontia and oligodontia
what is total anodontia? and what is it associated with?
- complete absence of teeth (rare)
- often associated with hereditary ectodermal dysplasia (abnormal development of ectoderm)
what is partial anodontia/hypodontia? and what teeth does it most commonly effect?
- partial absence of teeth
- most common in third molars especially maxillary
- 2nd most common in maxillary lateral incisors
- 3rd most common in mandibular second premolars
what is oligodontia?
absence of more than 6 teeth
what is supernumerary teeth, how is it caused and where is it most commonly found?
- more teeth than usual
- results from splitting of permanent tooth bud
- occurs in both permanent and primary dentition most often in maxilla
- most common: maxillary incisors
- 2nd most common: third molars (mostly maxilla)
- 3rd most common: mandibular premolars
what is a mesiodens?
small, cone shaped supernumerary tooth that forms between maxillary central incisors (less commonly occurs between laterals/canines)
what are supernumerary third molars?
- “fourth molars”
- rarely erupt
- often found on accident on x-ray
what are supernumerary mandibular premolars?
- generally resemble premolars anatomically
- often crowded or positioned lingually or facially
what is macrodontia?
normally shaped tooth, but larger in size
- usually seen in incisors and canines
- often associated with giantism
what is microdontia?
normally shaped tooth, but smaller in size
- usually maxillary laterals and third molars
peg shaped laterals are considered what type of abnormality and occur from?
a form of microdontia where the laterals are cone shaped
- development occurs from one lobe rather than 4
what is gemination (twinning) and where is it most common?
- incomplete splitting of a single developing tooth into two where the tooth has only 1 root and 1 pulp chamber
- most common in primary dentition and maxillary anteriors
**if gemination tooth splits it would develop an extra tooth
what is fusion and how does it occur? would there be more or less teeth in the arch?
- two separate adjacent crowns FUSE and appear to be double in width AND two separate roots fuse with TWO separate pulp chambers
- occurs by pressure of force during development of adjacent teeth
- less if the fused teeth are counted as one
what is Hutchinson’s Incisors (congenital Syphilis)?
- where syphilis is passed to child by the mother and causes the incisors to appear notched, broad cervical or more narrow incisally
what is mulberry molars (congenital syphilis)?
- first molars have occlusal anatomy made up of tiny tubercles and poorly developed cusps
- berry like shape is where the name comes from
what are Talon Cusps? what would happen if it is removed?
- extra cusp on the lingual surface of anterior teeth that may have a pulp horn
- may need endo therapy if removed
what are the two types of accessory molar cusps and how do they occur?
- tuberculum intermedium: 3rd lingual cusp on mandibular molars
- tuberculum sextum: extra cusp on mandibular molars (distal marginal ridge)
- occurs from localized hyperplasia and can occur on all molars
what is Dens In Dente and how does it occur and where does it occur?
- a tooth within a tooth
- results from invagination of epithelium of enamel organ prior to calcification
- almost exclusively in anterior teeth and in peg laterals
***clinically can see deep crevice near cingulum of incisors
what is a shovel shaped incisor?
incisor with pronounced cingulum and marginal ridges
what are enamel pearls, where are they found and what can they lead to?
- nodules of enamel with dentin core on root surfaces
- found in the furcation areas of molars
- enamel composition prevents normal root-bone attachment leading to periodontal problems
what is taurodontia?
- bull like root with a very long pulp chamber without cervical constriction
what is a dilaceration, where is it found and how is it caused?
- severe bend in tooth root
- often found in accessory roots
- due to traumatic injury or insufficient space for development
what is concrescence and why does it occur?
fusion of cementum of two adjacent teeth that usually occurs after eruption due to close proximity or excess cementum deposition
what is dwarfed (blunted) roots and why do they occur?
- normally sized crowns but small roots
- can result from orthodontic movement too rapidly
what is hypercementosis and what is it caused by?
- excess cementum around the root
- can be caused by trauma, metabolic dysfunction or periodical inflammation
what are accessory roots and where do they occur?
- extra small root off main root
- most often occur as a facial and lingual split (mesial and distal split is rare)
- can occur in third molars, mandibular canines, mandibular premolars, and other teeth
what are impacted teeth and where do they occur most?
- unerupted teeth due to mechanical obstruction (evolution of decreasing jaw size)
- most often in third molars and maxillary canines
what are the two types of misplaced teeth (ectopic eruption or transposition) and what tooth does it mostly occur?
labioversion- tooth located too far facial
linguoversion- tooth located too far lingually
- often in canines
what is ankylosis and what is it caused by?
- loss of periodontal ligament space which causes the tooth to fuse to the bone
- can be caused by infection or trauma to the PDL space
what is dysplasia?
abnormal development
what is hypomineralization?
too little mineral content
what is hypocalcification?
too little calcium
what is hypoplasia?
incomplete formation of tissue
what is amelogenesis imperfecta an what are some complications?
- hereditary enamel dysplasia that affects enamel development in both the primary and permeant dentition where there is a partial or complete lack of enamel
- abnormal tooth color, higher risk of dental decay, hypersensitivity, teeth likely undergo attrition
what is fluorosis and how is it caused?
- mottled enamel where the enamel changes to white or yellow/brown spots and may cause pitted enamel
- caused by ingestion of high concentrations of fluoride during enamel formation
what is focal enamel hypoplasia (hypomaturation), where does it occur and how is it caused?
- when enamel doesn’t develop properly
- usually occurs in the middle crown of smooth tooth surfaces
- can be caused by: trauma, infection of adjacent tooth, high fever during tooth formation, other interferences during enamel formation
what is dentinogenesis imperfecta and what are some symptoms?
- hereditary dentin dysplasia affecting odontoblasts and causes the teeth to be weak and susceptible to attrition
- teeth appear opalescent, light blue gray to yellow color and they have partial or total calcification of the pulp chamber
what is tetracycline staining and why does it occur?
- teeth appear yellow or gray brown: usually present with characteristic staining bands
- occurs when tetracycline is ingested by a pregnant woman or infant child
what is attrition? what is bruxism?
- wearing away of enamel and eventually dentin due to grinding of teeth seen on occlusal and incisal edges
- the excessive grinding of teeth
what is abrasion and why does it occur?
- mechanical wear of tooth structure often located in cervical areas due to hard toothbrushing or aggressive horizontal brushing
what is abfraction?
bending/flexure of tooth caused by heavy occlusal forces
what is erosion and what causes it?
- tooth loss due to exposure to chemicals
- bulimia, serve acid reflux, lemon sucking, excessive intake of carbonated beverages or acidic foods/drink
