Lecture 4- Permanent incisors Flashcards
First permanent tooth to errupt
mandibular 1st molar
Last PRIMARY tooth to be lost (at age 12, marking the end of the mixed dentition period)
primary 2nd molar
What is special about the maxillary central incisors? (5)
1) Esthetically the most prominent teeth
2) Most prone to trauma
3) widest anterior tooth
4) Curvature of the cervical line on mesial aspect of central incisor is greater than that of any other tooth, on any aspect
5) Only maxillary central and mandibular 2nd PM have straight conical roots
Maxillary anterior alignment
Inclined mesially form lateral view
labial and lingual geometric shape
Trapezoid
Proximal geometric shape
Triangle
Incisal geometric shape
Triangle/circle
Why is is a trapezoid?
Because central incisor is longer cervico incisally than it is wider mesiodistally
Distolabial line is more convex on central incisor than the mesiolabial line. This leads to
Point angles:
Mesio-incisal sharp approaching 90 degrees
Disto-incisal angle more convex
(pattern that is repeated in most teeth)
Mesial contact area
located at incisal third
Incisal embrasure size trend
INCREASE as you move POSTERIORLY
lingual embrasure is larger than labial embrasure
1) All teeth have lingual convergence
2) Proximal contact is facial to the center
Lingual pit
Sometimes found in lingual fossa
Cervical line on central incisor/proximal aspects
Curvature of the cervical line on mesial aspect of central incisor is greater than that of any other tooth, on any aspect
Incisal aspect of incisors
Mesiodistal dimension is slightly Greater than labiolingual dimension (bolded)
Cingulum off center to distal side
Incisal aspect of incisors
Lingual embrasure is larger than facial embrasure in ALL teeth
Incisal root
STRAIGHT CONICAL ROOT (incisors and 2nd maxillary premolar)
How many canals do incisors have? (pulp space morphology)
one
Occlusion of maxillary central incisor
Occludes with mandibular central AND lateral incisors
Maxillary lateral incisor
The last permanent incisor to erupt
Peg shaped lateral
lateral incisor that is significantly smaller than it should be
congenitally missing lateral incisor
3rd most common congenitally missing tooth
options for treatment: implants or removable prosthesis
Maxillary lateral incisor vs maxillary central incisor
lateral- more rounded outlines, more convex (more rounded incisal edge and incisal angles/mesial and distal)
smaller in all dimensions EXCEPT root length
Proximal contact area
Mesial: Junction of incisal and middle thirds
Distal: middle third
Embrasure area
Distoincisal embrasure is larger than mesioincisal embrasure (bolded)
Lingual aspect of lateral incisors
The marginal ridges, cingulum, and incisal ridge are more pronounced (bold) so more accentuated lingual fossa
lingual aspect of lateral incisors
lingual pit and lingual developmental groove are more likely
Proximal aspect of lateral incisors
Incisal ridge is in line with center of the root
Incisal aspect of lateral incisors
Looks like a triangle or OVAL outline (due to prominent cingulum)
Incisal ridge is thicker labiolingually compared to the central incisor
Pulp space morphology/number of canals of lateral incisors
one
root of lateral incisors
single root; distal curvature
Occlusion of lateral incisors
mandibular lateral incisor and canine
third most common tooth to be congenitally missing
maxillary lateral incisor
What is special about the Permanent Mandibular Central Incisor?
It is the smallest tooth
It is the most symmetrical tooth
labial surface of mandibular incisors is
bilaterally symmetrical (mesial half is identical to distal half)
Proximal contacts and embrasures of mandibular central incisors
Both mesial and distal contact areas are at the same level at the incisal third (bolded) of crown near the mesial and distal incisal angles
Both incisal embrasures are the same size and very small
lingual aspect of mandibular central incisors
The marginal ridges are ill defined lingual fossa small and shallow Shallow smooth cingulum No lingual pit (bolded)
Incisal aspect
Labiolingual greater than mesiodistal dimension (opposite maxillary teeth).
(bolded)
Root of mandibular central incisors
Root is convex labially and lingually and flattened mesially and distally (bolded)
Pulp space morphology mandibular central incisors
TWO canals with prominent single pulp horn (bold)
occlusion
with maxillary central incisor
