Permanent Anterior Teeth - IncisorsChapter 16

Central Incisor (Facial view)

http://www.youtube.com/watch?v=2F1DuV1cxpU

Maxillary Incisors

Location – anterior Teeth #s – 7, 8, 9, and 10Eruption – 7-9 years

8 97 10

Maxillary Central Incisor

Location – most anterior tooth on maxillaTeeth #s – 8 & 9Eruption – 7-8 yearsShape - Shovel

8 9

Labial View

Perikymata (imbrication lines) Horizontal lines on the

enamel surface of newly erupted teeth

Mamelons (tubercles or scallops) Rounded scallops or

tubercles near the incisal edge of newly erupted teeth

Woelfel and Scheid. Dental Anatomy. 6th ed. Lippincott Williams and Wilkins, 2002, p. 92.

Labial View

Developmental grooves Mesiolabial Distolabial

Brand and Isselhard. Anatomy of Orofacial Structures. 7th Ed. Mosby, 2003, p. 120.

Labial View

Incisal edge over root

Labial View

Wide mesiodistally

Sharper mesioincisal line angle than distoincisal line angle

Distocervical part of crown elevates. D M

Labial and Lingual Height of Contour

HOC: Widest portion viewed from the proximal (mesial and distal) views

Cervical 1/3

Mesial and Distal ViewCEJ more curved on mesial than distal

Lingual View

Cingulum (4th growth center) swings to the distalShovel shaped Distinct mesial

marginal ridge and distal marginal ridge

Prominent lingual fossa

Mesial marginal ridge

Fossa

Distal marginal ridge

Root

Cone shape

Plaque Retention

Labial depressionsNear cervical lineLingual fossa

Maxillary Lateral Incisor

7

Maxillary Lateral Incisors

Location –Distal to central incisors, mesial to cuspidTeeth #s – 7 & 10Eruption – 8-9 years

710

Lateral Incisor Compared to Maxillary Central Incisor

Smaller Rounder line angles Similar in that the mesioincisal line angle is sharper than distoincisal line angleOblongLabial depressions do not appear

Lingual View

Distinct marginal ridgesMesiomarginal ridge is longer and straighter than distomarginal ridgeDeep lingual fossa Distinct lingual pitCingulum prominent and centered

Mesial and Distal Views

Mesial CEJ is curved more than distalCEJ dips closer to incisal on the mesial than the distal

Height of Contour

Labial and lingual height of contours in cervical 1/3

Root Anatomy

Longer and thinner than central incisorApex curves distally (90% of the time)Oval in cross-section

MANDIBULAR INCISORS

http://www.youtube.com/watch?v=fS22tHO2DpA

Mandibular Incisors

Anterior teethTeeth #s: 23, 24, 25, 26

262626 25 24 23

Eruption of Mandibular Incisors

Central: 6 – 7 yearsLateral: 7 – 8 yearsRoots complete: 9 – 10 yearsGenerally after 1st permanent molars

Occlusion

Mandibular central occludes with maxillary central incisor

Lateral incisor occludes with maxillary central and lateral incisor

Mandibular Central Incisor

Mamelons on newly erupted teethCingulum is not as prominent as maxillary Developmental grooves not prominentMarginal ridges not distinct 2425

Labial View of Mand. Central Incisor

Smallest tooth in the mouthSymmetrical – difficult to tell left from rightDistoincisal angle slightly more round than mesioincisal angle 2425

Mandibular Central Lingual View

Lingual surface narrower than labial surfaceRelatively smooth – shallow lingual fossaSmall centered cingulum

Mesial View

Incisal edge lingual to root axis line, otherwise bilaterally symmetrical over the rootMesial CEJ more curved than distal CEJ

Incisal View

Incisal angles equal sharpness, approximately 90º Broad (wider) labiolingually than mesiodistallyLabial surface flat and lingual surface convex due to cingulumCingulum centered

90º mesioincisal and distoincisal angles

Height of Contour

Labial and lingual height of contour in cervical third

Contact Areas

Mesial and distal contact areas in incisal 1/3Distal contact area slightly more cervically located

Root Anatomy

Mesial and distal root depressions, BOW shaped rootCrown centered over the root – apex may bend slightly to the distal

Plaque and Calculus Retention

May have plaque or calculus accumulation

MANDIBULAR LATERAL INCISORS

Location

Distal to central incisor and mesial to cuspid

26

Mandibular Lateral Incisor - Labial View

Not as symmetrical as central incisorLarger than central incisor in same mouthDistoincisal angle more rounded than mesioincisal angleDistal surface convexCrown tilts to distal – looks bent at cervix

Lingual View of Mandibular Lateral Incisor

Mesiomarginal ridge is longer than distomarginal ridgeShallow lingual fossaDistal surface bulges from the incisal view

Mesial marginal ridge

Distal marginal ridge

Incisal View

Distolingual twistCingulum twisted (off-center) to the distal

Mesial View

Incisal edge lingual to root axis lineCEJ is curved more on the mesial than the distalRoot depressions possible

Distal View

Root depression or concavity always present on the distal surface, known as a “KIDNEY SHAPE”

Height of Contour

Labial and lingual HOCs in cervical 1/3

Contact Areas

Mesial and distal contact areas in incisal 1/3

DistalMesial

Root Anatomy

Mesial and distal root depressionsApex may curve slightly to the distal