dental embryology, histology, and anatomy Ch 1 and 15 quiz

dentition

• used to describe the natural teeth in the jaws

• a person has two dentitions during a lifetime: primary and permanent dentition

primary dentition (baby teeth)

• primary school ~ first school = primary dentition ~ first set of teeth

• 20 teeth in total

• 8 incisors

• 4 canines

• 8 molars

• NO premolars

permanent dentition (adult teeth)

• second dentition to develop

• 32 teeth in total

• 8 incisors

• 4 canines

• 8 pre molars

• 12 molars

universal numbering system (UNS)

• united states - universal

• Starts on patients upper right side, 1-16, then dropping down to mandible starting at 17-32

• primary dentition follows the same pattern, using letters A-T

international numbering system (INS)

• teeth are designated from each other by using a two digit code

• the first digit corresponds to the specific quadrant the tooth lies in, with the second number indicating the position of the tooth in the quadrant

• for example: the right central maxillary incisor would be tooth “11”

• primary dentition starts first quadrant at 5

palmer notation method

• known as the military tooth numbering system

• teeth are designated from each other with a right-angle symbol indicating the quadrants and arch with tooth number placed inside

dentition periods

• there are two dentition, but three dentition periods

• primary

• mixed

• permanent

mixed dentition period

~6 to 12 years

• eruption of permanent mandibular first molar (6-year molar)

• primary and permanent

• fastest and most noticeable

primary dentition period

~6 months to 6 years

• eruption of primary mandibular central incisor

• primary

• beginning

permanent dentition period

After ~ 12 years

• shedding of last primary tooth

• usually permanent

• slowest and least noticeable dentition period

dental anatomy

is the area of the dental sciences dealing with the morphology or form of the teeth, both the crown and root. Restorative dentistry uses many specific dental anatomy terms when discussing treatment and pathology.

alveolus

• Alveolar process means bone.. it needs an alveoLUS because the tooth needs less bone (hole) for the tooth to go in

• surrounds and supports each tooth

• the bone of the tooth socket

• located in the alveolar process (tooth bearing part of each jaw)

occulsion

• is the method by which the teeth of the mandibular arch come into contact with those of the maxillary arch

mandible

• man down! (lower jaw)

D-A-Q-T system

• is based on the tooth within its quadrant

• D for dentition (primary, permanent)

• A for arch (maxillary or mandibular)

• Q for quadrant (1st,2nd,3rd, or 4th)

• and T for tooth type (molar, premolar, canine, incisor, etc)

ex: (D) permanent, (A) mandibular, (Q) left (T) first premolar

sextants

• further divide each dental arch into three parts according to the relationship with the midline

• each arch is divided into left and right

• central six incisors and canine are considered “anterior” or “front facing” sextant

• remaining molars and considered either left or right posterior sextant

crown

• each tooth consists of a crown and one or more roots

• can be seen on the top of the tooth (CROWNS the tooth)

• each crown has dentin covered by enamel

• dentin meets enamel at dentinoenamel junction (DEJ)

root

• each tooth consists of a crown and one or more rooths

• the root consists of dentin surrounded by cementum

• the cementum meets the enamel at the cementoenamel junction (CEJ)

pulp cavity

• consists of a pulp chamber, pulp canal or canals, an apical foramen, and possibly a pulp horn

• covered by dentin

• consists of nerves, blood vessels, and the connective tissues of the tooth

anatomic crown

• anatomy never changes

• is the entire part of the tooth that is covered by the enamel

• stays constant except for attrition and other physical wear

clinical crown

• is the part of the anatomic crown that is visible and not covered by the gingiva

• height is determined by the location of the marginal gingiva

• depends on health of patient

• “what is visible?”

apical

• the tip of the tooth’s root

• the hole that the pulp and nerves use to enter the alveolar process

restorations (clinical connection)

• certain restorations may cover the entire anatomic crown area; these are full artificial crowns (caps)

• post and core may be placed within the crown and root to help with the buildup of restorative material to support an individual restoration

root concavities

• many surfaces of the roots have depressions or root concavities

• these indentations in the root surface commonly occur on the proximal root surfaces of anteriors and posteriors and the buccal and lingual surfaces of molars

• an area between two or more of these roots is a furcation

• should be CAREFULLY explored during instrumentation appointments and charted

crown lengthening (clinical connection)

a full artificial crown should ideally cover the entire prepared anatomic crown, but enlarges gingival tissue or loss of anatomic crown structure may require a surgical periodontal procedure called crown lengthening to increase the amount of the clinical crown and reduce the surrounding gingival tissue by removal

masticatory surface

• Is the chewing surface on the most superior surface of the crown

• incisal surface for anterior teeth

• occlusal surface on posterior teeth

• both have lineal elevations (ridges) which are named according to location

cusps

• the masticatory surfaces of both canines and posterior teeth have at least one major elevation; a cusp

• cusps contribute to a significant part of the tooth’s surface

mesial

the surface of the specific tooth closest to the midline

distal

the surface of the specific tooth farthest from the midline

proximal

together, both the mesial and distal surfaces between adjacent teeth are considered the proximal

interproximal space

the area between adjacent tooth surfaces

contact areas

• the area where the crowns of adjacent teeth in the same arch physically touch on each proximal surface is the contact area, or as referred to by clinicians, the contact

• (the clicking sound you hear when flossing between teeth and resistance felt are due to strong contacts)

height of contour

• crest of curvature

• is the greatest elevation of the tooth either incisocervically or occulsocervically on a specific surface of the crown when viewing its profile from the labials or buccal and the lingual

embrasures

• when two teeth in the same arch come into contact, the curvatures next to the contact areas form spaces considered embrasures.

line angle

is formed by the lines created at the junction of two crown surfaces and the name is derived by combining the names of the two surfaces

point angle

• is another way to determine the specific area of the crown

• the junction of three surfaces of the crown, the point angle takes its name from those three surfaces

thirds

• a crown can be divided both horizontally and vertically into three parts, or thirds, to designate specific tooth areas

tooth form

• related to the function during mastication for the tooth type, as well as to its role in speech and esthetics

• the form and function of each tooth type are similar for both the primary and permanent dentitions

incisors

• instruments for biting and cutting food during mastication (triangular proximal form of their crowns)

canines

• because of the tapered shape and the prominent cusp of their crowns, function to pierce or tear food during mastication

premolars

• only found in permanent dentition

• assist canines in piercing and tearing food because of prominent cusps of their crowns during mastication

• assist molars in grinding food due to wide masticatory surface (occlusal surface)

molars

• the molars function in grinding food during mastication, assisted by the premolars

• the wide masticatory surface, the occlusal surface of the molars, with the prominent cusps, function during mastication

root axis line (RAL)

an imaginary line representing the long axis of a tooth, drawn in a way to bisect the root (and thus the crown) in the cervical area into two halves

primary tooth eruption sequence

• bottom central incisors (6-10 months)

• upper central incisors (8-12 months)

• upper lateral incisors (9-13 months)

• lower lateral incisor (10-16 months) and upper first molar (13-19 months)

• lower first molar (14-18 months)

• upper canine (16-22 months)

• lower canine (17-23 months)

• lower second molar (23-21 months)

• upper second molar (25-33 months)

permanent dentition eruption

• first molars (6-7 years)

• 2. lower central incisor (6-7)

• 2. upper central incisor (7-8)

• 3. lower lateral incisor (7-8)

• 3. upper lateral incisor (8-9)

• 4. lower canine (9-10)

• 4. upper first premolar (10-11)

• 5. lower first premolar (10-12)

• 5. upper second premolar (10-12)

• 6. upper canine (11-12)

• 6. lower second premolar (11-12)

• 7. second molar (11-13)

• 8. third molar (17-21)

W 12 6 6 12 W

W 12 6 6 12 W