L3 - Max & Mand Incisors

DEN5404C Lecture 3

Max Incisors

#7, 8, 9, 10

Max central incisor eruption

7-8 years

Max lateral incisor eruption

8-9 yearseruption begins at 8-9 years

Central lobe

smallest, occupies ¼ of mesiodistal dimension

Mamelons

• rounded projections on incisal edge of newly erupted teeth

• 3 mamelons

• worn after eruption

F/Labial developmental grooces

also called lines, depressions, labial lobe grooves formed by joining of lobes

Imbrication lines

curved lines in cervical 1/3, not always present

Proximal contacts

• D contact in incisal near junction of middle third

  • M contact in incisal third near MI angle

Lingual anatomy

Cingulum, M/D marginal ridge, L fossa, I edge, crown has L taper

Cingulum

broad & smooth, slightly offset to D

L ridges

from cingulum to L fossa, forming W-shape

Root shape, apex, & cross-section

cone-shaped, blunt apex, & cross-section form is rounded triangle

Unique characteristic of max central incisor

• wider - MD crown dimension is largest of anteriors

  • more square - MD & IC crown dimension closer than any incisor

Incisal line angle

• D & I surfaces create obtuse angle (wider)

  • M & ! create acute angle (narrow)

Embrasure spaces

Get wider the more posterior you go

Marginal ridges

M ridge is longer & straighter than D, D is shorter & more curved

Linguogingival groove

Found where lingual fossa joins cingulum

Max lat incisor

Narrowest of any max tooth, MD and FL dimensions are closer than any ant tooth, incisal edge curve greatest of any incisor

Max lat incisor distal contact

Centered incisiocervically & faciolingually, shared w/ 4 teeth: max canine, max 1st & 2nd molar, mand 2nd molarW

Which tooth is subject to more anomalies than any other tooth?

max lat incisor

Mand incisors #

#23, 24, 25, 26

Mand central incisor eruption

6-7 years

Mand lat incisor eruption

7-8 yrs

Mand incisors lingual surface

Smooth, no pits/fissures, least cingulum, no developmental lines

Incisal ridge vs. edge

Incisal ridge becomes edge after sloped & flattened over time

Labial vs. lingual inclination

Max incisal edge (IE) develops lingual inclination, mand IE develops labial inc

Mand incisor root

• conical & narrow

• central I is shorter & thinner than lateral

• curves distally

Differences btw central & lat mand incisors

• Crown dimensions - lat is longer & wider

• MI & DI angles - central is symmetrical, lat D surface is more convex

• incisal edge form - central is flat/perpendicular, lat slopes

• prox contacts - M&D of central and M of lat are in incisal 1/3 at same position, D contact on lat is farther cervically

• ingual surface - marg ridges on cent near I edge & slightly concavity, M marg ridge slightly longer than D for lat

Unique characteristics mand incisors

• fewest F developmental lines/grooves of any tooth

• Smoothest lingual surface of ant teeth

• smallest cingulum

• IE lingual to long axis

• central are smallest teeth & only tooth thats bilaterally symm

• cent has sharpest prox angles

• crown twisted on root