MAXILLARY CENTRAL INCISOR Dr. Ram Simsuangco

Maxillary Central Incisor - develops from 4 primary centers of formation (lobes); 3 labial lobe and 1 lingual lobe - Widest mesiodistal dimension; generally smooth MORPHOLOGY OF NEWLY ERUPTED CENTRAL INCISOR presence of mamelons Two shallow developmental depressions labially Perikymata fine horizontal lines on the crown surface 2 basic forms: wide cervix and narrow cervix Variations: short root, unusually long crown, shovel-shaped incisors

Contact Area Mesial- incisal 3rd, very near or approaching the incisal angle Distal near the junction of the incisal and middle 3rd

Labial aspect Crown outline is trapezoidal Length of crown usually greater than MD width Outline of crown: Mesial slightly convex Distal outline more convex Mesioincisal angle = sharp ; Distoincisal angle = more convex Incisal outline regular and straight in MD direction Cervical outline: semi-circular with curvature rootwise Root is cone-shaped, with a regularly blunt apex; root is 2 or 3 mm more longer than crown Root axis line of crown and root labially tends to parallel the mesial outline of the crown and root

Lingual Aspect Crown outline is trapezoidal Smooth convexity at the cervical 3rd, cingulum is located off centered towards distal Bet. Mesial and distal marginal ridges is a shallow concavity, the lingual fossa Shovel-shaped incisors incisors with deep lingual dossa and prominent marginal ridges Linguoincisal edge is raised, in level with MRs There are developmental grooves extending from the cingulum to the lingual fossa Crown and root taper lingually Root surface on lingual is narrower than labially

Mesial Aspect Crown is triangular or wedge-shaped Root axis line bisect incisal ridge and root apex, Incisal ridge is in line with center of the root Crest of curvature at the cervical 3rd greatest labiolingual measurement CEJ curves incisally to a noticeable degree than any of the tooth in the mouth Root is cone-shaped, apex is usually bluntly rounded

Distal Aspect Similar to mesial; except crown is thicker toward incisal 3rd Less curvature of CEJ Most teeth turned a little on their root bases, in order to adapt to the curvature of the dental arch, creating an illusion of greater thickness on the distal

Incisal Aspect Labial surface is relatively broad and flat especially towards the incisal 3rd Cervical portion of crown is convex, arc is described as broad Incisal ridge slope toward the lingual Lingual outline tapers towards the cingulum Cingulum off centered to the distal Prominent mesiolabial and distolabial line angles Labiolingual calibration of the crown is more than two 3rds as great as the MD calibration