MISCELLANEOUS

 

MISCELLANEOUS

v  Radiographically

Ø  Anterior Palatine Foramen

§  Radiolucent and circular in shape

v  Waxing

Ø  Must Consider

§  Guiding (non-supporting) cusps are related to the Interproximal areas or developmental grooves

§  Supporting cusps are related to the marginal ridge and fossae

§  Supporting cusps are aligned with supporting cups of the same quadrant

§  Guiding (non-supporting) cusps overlap facial to mandibular teeth and lingual to maxillary teeth

v  Attrition

Ø  Facets usually develop on

§  Linguoincisal of Mx centrals

§  Facioincisal of Mn canines

·         Attrition on a Mn Canine, what would the Mesial ridge look like??  M ridge would be shorter than D

·         Attrition of a Mx Canine, what would the Mesial ridge look like?? M ridge would be longer

§  Linguoincisal of Mx canines

§  Incisal edges of Mn laterals is done with Mx central AND lateral incisors, NOT Canines

§  Pt with Normal Class I, has wear facets on inner aspect of facial cusp of Mx PM2, these can only be caused by Mn PM2

§  LEAST likely spot for attrition is labioincisal area of Mx lateral incisor

v  Anodontia

Ø  Complete (usually with Ectodermal Dysplasia)

Ø  Partial

§  Usually 3rds (Max more) >Max laterals >Mand 2^nd PMs

Ø  Rule:  if only one or a few teeth are missing, the absent tooth will be the most distal (if molar, then 3^rd); if premolar, then 2^nd; if incisor, then lateral.

v  Oligodontia

Ø  Many, but not all teeth

Ø  A developmental abnormality characterized by the presence of fewer than the usual number of teeth

Ø  Hypodontia

§  Few gone

Ø  Old school classifications

§  Heterodont – Human teeth, or several kinds of teeth, serving a variety of fxns

§  Diphyodont – To produce 2 sets of teeth (perm/prim)

§  Monophyodont – 1 set of teeth

§  Polyphyodont – Teeth being replaced continually (amphibians)

§  Homodont – teeth are all alike

·         A typical nonpoisonous reptile is a homodont (What a lame question!)

§  Hypsodont – long teeth (High crowned)

§  Haplodont – a primitive basic tooth form having a single conical crown and a single root

§  Selenodontic – Longitudinal Mesiodistal Ridge formation (Grazing animals, along with Hypsodontic)

Ø  Teratogens affecting Dentofacial Development

§  Worse during first trimester

Teratogen	Effect
ASA, Valium, Dilantin, Cigarettes CMV, Toxoplasma Ethyl Alcohol Rubella Virus X-radiation Vitamin D excess	Cleft Lip and Palate Microcephaly, Hydrocephaly, Microphthalmia FAS àCentral mid-face discrepancy Microphthalmia, Cataracts, Deafness Microcephaly Premature suture closure

Ø  Dental hypoplasia

§  If it occurs, it will be present when the teeth erupt

Ø  Tetracycline staining

§  A 5-year-old child is treated with large doses of tetracycline over a one year period.  The perm teeth least likely to show staining are lateral incisors, canines, and premolars.  Perm centrals & M1s are more likely to stain.

·         Kaplan gives this explanation: “Since the child is 5 years old, the teeth erupting at 6 or 7 will be MOST likely to show staining, and those erupting later are less likely.  On average, centrals erupt at 7, laterals at 8, canines at 11, PM1s at 9, and M1s at 6.

·         So most likely stains teeth erupting 1-2 years after tetracycline usage

v  Hypercementosis

Ø  Excessive calcified tissue formation at the root apices

v  Ankylosis

Ø  Fusion of the alveolar bone to a tooth

Ø  Also when different tooth obstructs obstructs

v  Dentin Islands

Ø  Most common in Mx 2^nd PM and in Mn Canine

v  Caries/Dental decay

Ø  Areas susceptible to caries include pits & fissures, Facial surfaces cervical to the height of contour (Cervical Thirds), & proximal surfaces

Ø  On molars, the L of Mx M1s & B of Mn M1s are most likely to develop caries (due to those fissured grooves)

Ø  Least likely to occur on cusp tips

Ø  Mandibular canine is most likely to resist invasion by caries

v  Periodontal Disease

Ø  The following morphologic variations tend to accelerate existing periodontal disease

§  Enamel projections, fused roots, and excessively short roots

v  Malpositioned teeth

Ø  If a Mn PM2 is linguoverted, there is an area of overcontour affecting the lingual gingival sulcus

§  Linguoversion means the tooth is lingual to the normal position

v  Supraeruption

Ø  Tendency of teeth to erupt into an empty space; tends to follow extraction of opposing teeth

Ø  An extruded Mn R M3 (Mx M3 extracted) will most often impede a protrusive Mn movement

v  Anterior open bite

Ø  More common in African Americans

Ø  Can be caused by thumb sucking

§  Protrusion of max incisors

§  Constriction of max arch

§  Lingual inclination of mand incisors

§  Rotation of max laterals

§  Class II Malocclusions

Ø  Can be caused by abnormal swallowing (tongue Thrust)

Ø  Can be caused by mouth breathing

§  Presents with facial gingival of Max bleeding, edematous, and red

§  Midline affected the most

v  Mx arch is slightly longer than Mn

Ø  Mx ¾ diameter is 128mm

Ø  Mn ¾ diameter is 126mm

v  Nerves:

Ø  3^rd→1^st molars innervated by PSA nerve (from V₂)

Ø  1^st molar→PMs innervated by MSA nerve (V₂)

Ø  Canines & incisors innervated by the ASA (V₂)

Ø  A branch of the cranial nerve V to the tongue may be anesthetized during administration of an IA block (think sensory – CN V)  -- the Lingual Nerve

v  Dryopithecus pattern

Ø  shows up most clearly in the mandibular first molar

Ø  It’s the name of the ape they think we descended from, blah, blah

v  Maxillary Molar of early Primate

Ø  Had a trigon made up of 3 cusp MB, ML, DB

Ø  Heart shaped/triangular

v  Rodents (Rodentia)

Ø  Mammalian order with continuously erupting teeth in which apices never form  

v  How many times do we swallow in one day? à 2,000 times a day

v  When does a person swallow the most??

Ø  Daytime, when they’re NOT eating