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Maxillary Incisors Dr. Syed Sadatullah Ibn Sina National College Jeddah.
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Maxillary IncisorsDr. SyedSadatullahIbn Sina National CollegeJeddah
IntroductionMaxillary incisors are four in numberMaxillary central incisor and lateral are similar in anatomy and complement each other in functionTheir major function is to cut teethMaxillary central incisor erupts between the age of 7 and 8 and it is the second permanent tooth to eruptMaxillary lateral incisor erupts between the age of 8 and 9
Maxillary Central Incisor Labial aspect • The mesial margin is straight and meets the incisal edge at right angle. The distal margin is shorter and more rounded. • The distoincisal angle is more rounded than the mesioincisal angle. • The labial surface is marked by two developmental groove and has convexity in cervical third. • Maxillary central incisor is the widest anterior tooth mesiodistally
Lingual aspect • The crown profile is same as that of labial surface except that there is a broad depression in the central portion called the lingual fossa and a well developed cingulum. • The lingual fossa is bordered by mesial and distal marginal ridges on the sides and the cingulum cervically. • The cervical line on labial and lingual surface is convex apically.
Mesial aspect • From the mesial aspect the labial margin is convex • The lingual margin is ‘S’ shaped, being convex near cingulum and concave in the middle • Mesial curvature of cervical line (3.5mm) is the most pronounced compared to any other tooth. • The cervical line on the mesial and distal surface is convex incisally
Distal aspect Distal aspect • Distal surface is very similar to the mesial surface.
Incisal aspect Incisal aspect • The crown and incisal margin are centered over root • Crown profile is almost bilaterally symmetrical • The incisal margin of newly erupted teeth show three elevations called mamelons. They correspond to the developmental lobes
Average Dimensions in millimeters Crown Length Root Length Mesiodistal Diameter at Contact Area Mesiodistal Diameter at Cervical Line Labiolingual Diameter at Crest of Curvature Labiolingual Diameter at Cervical Line Curvature of Cervical Line M D 10.5 13.0 8.5 7.0 7.0 6.0 3.5 2.5 • Root • The root is straight and tapers from the cervical line to the apex giving it a conical shape • The root ends in a blunt apex.
Maxillary Lateral Incisor • The general shape is similar to maxillary central incisors except that they are shorter and narrower. • Next to third molars maxillary lateral incisors are the teeth that show most variation in crown size, shape and form • The mesioincisal and distoincisal angles are more rounded than the corresponding angles of the maxillary central incisor • On the lingual aspect the marginal ridges and cingulum are more prominent
Mesial aspect Lingual aspect Labial aspect Distal aspect