Permanent Anterior Teeth - Incisors Chapter 16

Central Incisor (Facial view)

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

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

Maxillary Central Incisor Location – most anterior tooth on maxilla Teeth #s – 8 & 9 Eruption – 7-8 years Shape - 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 View CEJ more curved on mesial than distal

Lingual View Cingulum (4th growth center) swings to the distal Shovel shaped Distinct mesial marginal ridge and distal marginal ridge Prominent lingual fossa Mesial marginal ridge Distal marginal ridge Fossa

Root Cone shape

Plaque Retention Labial depressions Near cervical line Lingual fossa

Maxillary Lateral Incisor 7

Maxillary Lateral Incisors Location –Distal to central incisors, mesial to cuspid Teeth #s – 7 & 10 Eruption – 8-9 years 10 7

Lateral Incisor Compared to Maxillary Central Incisor Smaller Rounder line angles Similar in that the mesioincisal line angle is sharper than distoincisal line angle Oblong Labial depressions do not appear

Lingual View Distinct marginal ridges Mesiomarginal ridge is longer and straighter than distomarginal ridge Deep lingual fossa Distinct lingual pit Cingulum prominent and centered

Mesial and Distal Views Mesial CEJ is curved more than distal CEJ 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 incisor Apex curves distally (90% of the time) Oval in cross-section

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

Mandibular Incisors Anterior teeth Teeth #s: 23, 24, 25, 26 26 26 23

Eruption of Mandibular Incisors Central: 6 – 7 years Lateral: 7 – 8 years Roots complete: 9 – 10 years Generally 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 teeth Cingulum is not as prominent as maxillary Developmental grooves not prominent Marginal ridges not distinct 25 24

Labial View of Mand. Central Incisor Smallest tooth in the mouth Symmetrical – difficult to tell left from right Distoincisal angle slightly more round than mesioincisal angle 25 24

Mandibular Central Lingual View Lingual surface narrower than labial surface Relatively smooth – shallow lingual fossa Small centered cingulum

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

Incisal View Incisal angles equal sharpness, approximately 90º Broad (wider) labiolingually than mesiodistally Labial surface flat and lingual surface convex due to cingulum Cingulum 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 1/3 Distal contact area slightly more cervically located

Root Anatomy Mesial and distal root depressions, BOW shaped root Crown 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 incisor Larger than central incisor in same mouth Distoincisal angle more rounded than mesioincisal angle Distal surface convex Crown tilts to distal – looks bent at cervix

Lingual View of Mandibular Lateral Incisor Mesial marginal ridge Mesiomarginal ridge is longer than distomarginal ridge Shallow lingual fossa Distal surface bulges from the incisal view Distal marginal ridge

Incisal View Distolingual twist Cingulum twisted (off-center) to the distal

Mesial View Incisal edge lingual to root axis line CEJ is curved more on the mesial than the distal Root 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 Mesial

Root Anatomy Mesial and distal root depressions Apex may curve slightly to the distal