Anatomy By Tooth Flashcards
1
Q
Primary Dentition Facts
A
Primary teeth are less mineralized than permanent teeth, and are consequently more worn
The difference in space from the primary to the permanent dentition is 2 – 4 mm (arch length)
Mamelons that remain beyond the age of 10 generally indicate an open bite
Calcification of the primary roots is normally completed at 3 – 4 years of age
The usual pattern of eruption for primary teeth is: centrals, laterals, 1st molars, canines, 2nd molars
Lowers before uppers except laterals
The primate space develops in the maxillary primary dentition between the lateral and canine
The mandibular primary primate space is located between canine and first molar
The primary spacing for the anterior teeth is caused by the growth of the dental arches
The direction of primary enamel rods in the cervical third is in an occlusal direction
Primary molar roots are more divergent than permanent molars
A primary molars lack an identifiable root trunk
Primary mand central has the smallest faciolingual crown dimension
The prim and perm mandibular central incisor is the most bilaterally symmetrical tooth
In delayed resorption of primary incisors the permanent incisors usually erupt lingually
Primary Central incisor has a prominent cervical ridge both on the facial and lingual surfaces
From a facial view, the crown of a primary canine has a mesio-incisal slope longer than the disto-incisal
The cusp tip of the primary canine is generally off set to the distal
2
Q
Primary Mx 1st molar
A
Has a crown somewhat resembles a permanent premolar
Has roots that resembles a typical permanent mx molar
The cervical ridge is most prominent for primary MX teeth on the MF surface of the 1st molar
3
Q
primary Mx 2nd molar
A
The primary tooth that generally has an oblique ridge (resembles perm max 1st molar)
The only primary posterior tooth to have oblique & transverse ridges & DL groove
The primary 2nd molar generally exhibits Cusp of Carabelli
The last primary teeth to erupt are the Mx 2nd Molars
Has more cusps than the primary first molar
4
Q
Primary Md 1st molar
A
- The primary tooth that has the most distinctly prominent facial cervical ridge
- On facial view, the CEJ is most apically positioned on the mesial 1/3 (slopes down bc of prominent cervical ridge)
- Usually has a distal triangular fossa
a. Central fossa usually displaced to the distal, aka called “distal” or a “main” fossa too - Has the most distinct transverse ridge
- Does not look like any permanent tooth
- The primary teeth that differ most from permanent teeth are the Md 1st molars
- ML cusp = highest and sharpest cusp (not MB)
5
Q
Mx central incisors
A
- The teeth whose function is primarily biting
- The mx central has the greatest facio-lingual axial inclination
- GREATEST cervical curvature (on mesial) of any other tooth
a. CEJ deeper on (think of mx central)
- ant teeth than post teeth
- mx than md
- mesial side of tooth than distal
- greatest on mesial of the mx central - Only anterior teeth that are wider mesio-distally than facio-lingually
- Greatest MD crown dimension of any anterior tooth
- Measurement is nearly identical for Inciso-Cervical vs Mesio-distal SQUARE from facial or lingual
- The contact between a mx central and lateral incisor make the lingual embrasure larger than the facial (typical for most teeth) [poc is more facial than lingual]
- The incisal embrasure between the mx centrals is smaller than the one between the central and the lateral
- The non-molar tooth that most frequently has a mesial and distal pulp horn
- The non-molar tooth that is least likely to have a bifurcated root
6
Q
Mx lateral incisors
A
- Most crown shape variability
- Most crown morphology deviation (except for 3rd molars)
- Most often tooth to be in abnormal relation and contact with adjacent teeth
- Most often congenitally missing (other than 3rd molars)
- The ant tooth that would most likely demonstrate lingual pit caries
- The DL groove of mx lateral incisor is an anatomical feature that complicates root planning
- The disto-incisal angle of the mx lateral has the greatest convexity of all mx anterior teeth
- Most prominent marginal ridge of all ant teeth
- Most distinct and deepest lingual fossa’s of all anterior teeth
- Mesio-distal crown width is smallest of any mx tooth
- Mesio-distal measurement nearly identical to facio-lingual
- Mesio-distal width of mx lateral incisor is narrower than mx central
- Distal contact that farthest cervically of any incisor (usually very incisal)
- Distal contact centered both inciso-cervically and facio-lingually
- Mx lateral incisor is usually equal to or larger than the mx central in root length
7
Q
Md central incisors
A
- Distinguished by the cervical curvature, which is greater on the mesial than distal [CEJ curve]
- Md centrals and laterals most frequently have concave areas on M & D root surfaces
- Smallest crown dimensions of ANY tooth
- Most symmetrical crown
- Sharpest set of incisal angles (mesial and distal)
- Proximal contacts at same level
- Md central incisors and Mx 3rd molars generally occlude with only one opposing tooth
- The 1st succedaneous tooth [perm replacement to a primary] to erupt in the mouth (remember Permanent 1st molar is not succedaneous)
- B & L embrasures may be same size
8
Q
Md lateral incisor
A
- Crown tilts distally in relation to long axis
- Mesio-distal width wider than md central incisor
9
Q
Mx canine
A
- Greatest cervical prominence of any ANTERIOR tooth
- From proximal view, tooth with most vertical, straight lined axis
- Greatest overall tooth length (not longest crown)
- Longest root of any tooth (not longest crown)
- Greatest F-L crown dimension of any ANTERIOR tooth
- Distal contact is centered
(Contacts: “I Just jacked Michael Jackson’s Mo-ped”)
- Only tooth that has potential of contacting both anterior and posterior teeth
-
Cusp tip located facial to lingual axis (aka centered or slightly facial)
- so lingual is more visible from incisal view - Middle-facial lobe includes the cusp tip (opposite to MD canine)
- so lingual is more visible from incisal view -
Has distal bulge [stretched distally a tad]
- so mesial and distal are asymmetric - Crown form of canines from a facial view is Pentagonal
10
Q
Md canines
A
- Straightest mesial alignment of crown to root
- Mesial surface of crown almost parallel to long axis
- Longest crown dimension of any tooth
- Less prominent cingulum than the mx canine
- More narrow mesio-distally than max canine
- think of mx canine distal bulge (makes it bigger)
- think of md canine flat mesial (makes it smaller) - The anterior tooth that most frequently exhibits a bifurcated root
- The bifurcation for the md canine roots (when present) creates a facial and lingual root
-
Longest root length of any md tooth
- BE CAREFUL! – longest root of any tooth is the mx canine - In cross section, the root is IRREGULARLY OVAL
- In cross section at CEJ is OVOID but wider mesiodistally at labial
- In cervical cross section, root is flattened in MD direction
- Contact areas more incisally located than mx canine (think of md incisors)
- Continuous convex facial surface from incisal to apical end
- Makes a C shape from crown tip to root apex
- Incisal edge is lingual to long axis (opposite of mx canine)
11
Q
Mx 1st premolars
A
- Most pronounced developmental marginal groove of any mx tooth
- Mesial concavity that makes it difficult to adapt a matrix band
- In cervical cross section, root outline is kidney bean shaped
- In cervical cross section, pulp chamber floor is kidney bean shaped
- Non-molar tooth that most frequently exhibits 3 roots
- easy to remember, just think of the non-molar tooth that usually has 2 roots (can be bifurcated or trifucated) - Facial cusp is offset to distal
-
Longer mesio-facial cusp ridge than disto-facial cusp ridge (opposite of most teeth)
- only premolar with longer mesial cusp ridge (so does primary max canine) - Premolar with the steepest cusp inclines
- Mx premolars (1st and 2nd) lingual cusp are offset to the mesial
- buccal cusp is offset to distal - The posterior tooth that has the greatest cervico-occlusal crown height
- aka, from CEJ to tip of crown, it is the tallest posterior tooth - The non-molar teeth having the sharpest demarcation between pulp chamber & canal
12
Q
Mx 2nd premolars
A
- Size and position of cusps are more identical for the 2nd mx premolar than the 1st premolar
- Has 2 cusps of equal height
- Most symmetrical POSTERIOR tooth (has to do with equal height cusps)
- Has a short central groove with a lot of supplemental grooves (make is look wrinkly), instead of long central groove with a few supplemental grooves
- Has fossa that are closest in size compared to any other posterior teeth
13
Q
Md 1st premolar
A
- Uniquely prominent triangular ridge (snake eyes bc of no central groove)
- Frequently has both a separate mesial and distal pit (snake eyes)
- due to the prominent triangular ridge - Mesio-lingual developmental groove on tooth #21 (mand 1st premolar) originates from the occlusal pit and extends onto proximal surface
- Mesio-lingual developmental groove on tooth #21 extends onto the proximal surface
- Only tooth with a mesio-lingual groove
- Mesial lingual developmental groove makes mesial marginal ridge run at a 45-degree angle
- Mesial marginal ridge is located more cervical than the distal marginal ridge (due to 45-degree angle)
- More of occlusal surface can be seen from the mesial than distal (due to 45 degree Mesial Marginal Ridge)
- The occlusal outline is diamond shaped
- The rare second canal is most likely located to the lingual
- The only premolar that frequently has one pulp horn
- The lingual cusp is approximately 2/3 of height of facial cusp
- The lingual cusp is similar in development to the cingulum of a canine
- Lingual cusp in normal occlusion does not occlude
- Has most variation of all posterior teeth in facial vs lingual cusp height
- The facial masticatory mucosa (attached gingival) is narrowest on the facial aspect of md premolars
- It is the smallest posterior tooth, facio-lingually
- Closest of all MD TEETH in F-L vs M-D diameter
14
Q
Md 2nd premolar
A
- From the occlusal, the basic coronal outline is pentagonal
- the occlusal table outline is rectangular! - The premolar that is most likely to have a crescent-shaped central developmental groove
- The shortest interdental papilla is between the md 2nd premolar and the 1st molar
- The Y-type md premolar has one facial and 2 lingual cusps
- The Y-type md 2nd premolar has the same number of occlusal pits as the mx 1st molar
142. The ONLY premolar with multiple lingual cusps
143. The ONLY premolar with a lingual groove
144. The ONLY premolar with a central fossa
- The premolar that most frequently has single central pit
- Most congenitally missing premolar
15
Q
Mx 1st molar
A
- The occlusal outline form of an occlusal view is rhomboidal
- The mesio-facial and disto-lingual angles from occlusal outline tend to be acute angle
- The mesio-lingual and disto-facial angles from the occlusal outline tend to be obtuse angles
- Tends to taper toward facial, not lingual, so buccal embrasure is larger than the lingual
- The most prone facial and lingual surfaces of molars are the lingual of mx and the
ROOTS
- The largest root of mx 1st molar is the palatal
- The smallest root of the mx 1st molar is the disto-buccal
- From facial view, apex of lingual root is in line with the facial groove of the tooth
- Viewed from L, lingual root is in line with the midpoint of MD diameter
- When a 4th pup canal is present, its located in MB canal
FURCATIONS
- Of the 3 furcations, the mesial is the closest to the cervical line
- Of the 3 furcations, the distal is the furthest from the cervical line
OBLIQUE RIDGE
- The oblique ridge forms the distal boundary of central fossa
- The obtuse corners [ML and DF] coincide with the direction of the oblique ridge
- The center of the oblique ridge is at the same level [height] with the marginal ridge
- The oblique ridge connects the ML & DF cusps
- The ML cusp of mx molars occludes in the central fossa of md molars
DIMENSIONS
- Greatest FL diameter of the crown for all teeth (think of Cusps of Carabelli)
- Closest in size FL vs MD of any mx posterior tooth (be careful here, could ask of any tooth, of mx post tooth, of any post tooth – includes uppers and lowers)
- Has a wider MD width toward the facial than toward the lingual
CUSPS
- The DL cusp of mx molar is the only one that is not part of the molar cusp triangle [oblique ridge cuts it off]
- The ML cusp its largest and longest cusp
- Mx 1st molar is the tooth that is most likely forced into the mx sinus during an extraction
- Has distal concavity that can pose special problems in matrix placement
- Crown has a shorter DL groove than the 2nd molar
