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
