Permanent Maxillary Incisors PDF

PERMANENT MAXILLARY INCISORS  PERMANENT MAXILLARY INCISORS * The maxillary incisors are FOUR in number. * The maxillary central incisors are centered in the maxilla, one on either side of the median line , with the mesial surface of each in contact with the mesial surface of the ot...

PERMANENT MAXILLARY INCISORS  PERMANENT MAXILLARY INCISORS * The maxillary incisors are FOUR in number. * The maxillary central incisors are centered in the maxilla, one on either side of the median line , with the mesial surface of each in contact with the mesial surface of the other NB The maxillary and mandibular central incisors are the only neighboring teeth in the dental arches with mesial surfaces in contact. * The right and left maxillary lateral or second incisors are distal to the central incisors. * The maxillary central incisor is larger than the lateral incisor. * These teeth supplement each other in function, and they are similar anatomically * The incisors are shearing or cutting teeth. Their major function is to punch and cut food material during the process of mastication.  * These teeth have incisal ridges or edges rather than cusps such as are found on the canines and posterior teeth. INCISAL EDGE CUSP Differentiate between the two terms incisal ridge and incisal edge The incisal ridge is that portion of the crown which makes up the complete incisal portion. When an incisor is newly erupted, the incisal portion is rounded and merges with the mesioincisal and distoincisal angles and the labial and lingual surfaces. This ridge portion of the crown is called the incisal ridge. Differentiate between the two terms incisal ridge and incisal edge The term edge implies an angle formed by the merging of two flat surfaces. Therefore an incisal edge does not exist on an incisor until occlusal wear has created a flattened surface linguoincisally, which surface forms an angle with the labial surface. The incisal edge is formed by the junction of the linguoincisal surface, sometimes called the incisal surface, and the labial surface THE PERMANENT MAXILLARY CENTRAL INCISOR Calcification & Eruption Schedule Calcification begins 3-4 Months 1 1 Crown completed 4-5 years Eruption 7-8 years Root completed 9 years 8 9 11 21 THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The labial outline of the Crown is trapezoidal with shortest side cervically D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The labial outline of the Crown is trapezoidal with shortest side cervically. Cervicoincisal (CI) Length is (10.5 mm) Mesiodistal (MD) Diameter iS (8.5 mm) Mesiodistal MD at Cervix is (7.0 mm) D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT Mesioincisal angle is relatively sharp. Distoincisal angle is rounded D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The Distal outline of the crown is more convex than the Mesial outline (slightly convex but can be nearly straight ) D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The crest of curvature of mesial outline (mesial contact area) is at incisal third D M  THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The crest of curvature of the distal outline (distal contact area) is at the junction of incisal and middle third of the crown (higher towards the cervical line) D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The incisal outline is usually regular and straight in a mesiodistal direction NB: A newly erupted tooth shows mamelons on the incisal ridge D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT Cervical outline concave toward the incisal and the arc is part of a semicircle D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT Developmental groove : mesiolabial and distolabial Two straight, shallow grooves separating the three labial lobes D M THE PERMANENT MAXILLARY CENTRAL INCISOR LABIAL ASPECT The Root (13mm) is cone shaped with blunt apex 13mm which is slightly distal to the center with no developmental depressions D M THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT The lingual outline of the maxillary central incisor is the reverse of that found on the labial aspect. However, the lingual aspect of the crown is different when we compare the surface of the lingual aspect with that of the labial aspect. M D THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT From the labial aspect, the surface of the crown is smooth generally. The lingual aspect has convexities and a concavity ( concavo-convex ) more irregular cingulum NB. The convexity is called the "cingulum", and lingual fossa the central concavity is the "lingual fossa" F P THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT The outline of the cervical line is similar (semicircular) , but immediately below the cervical line a smooth convexity is to be found; this is called the cingulum M D THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT Mesially and distally confluent with the cingulum are the marginal ridges. M D THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT Between the marginal ridges, below the cingulum, a shallow concavity is present called the lingual fossa. M D THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT Outlining the lingual fossa, the linguoincisal edge is raised somewhat, being on a level with the marginal ridges mesially and distally, completing the lingual portion of the incisal ridge of the central incisor. M D THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT The crown and root taper lingually, so that the crown calibration at the two labial line angles is greater than the calibration at the two lingual line angles, and the lingual portion of the root is narrower than the labial portion. M D THE PERMANENT MAXILLARY CENTRAL INCISOR PALATAL ASPECT Usually there are developmental grooves extending from the cingulum into the lingual fossa. M D THE PERMANENT MAXILLARY CENTRAL INCISOR MESIAL ASPECT The crown is wedge shaped, or triangular, with the base of the triangle at the cervix and the apex at the incisal ridge F P THE PERMANENT MAXILLARY CENTRAL INCISOR MESIAL ASPECT The incisal ridge of the crown is on a line with the center of the root. This alignment is characteristic of maxillary central and lateral incisors. F P THE PERMANENT MAXILLARY CENTRAL INCISOR MESIAL ASPECT Labially and lingually, immediately coronal to the cervical line are the crests of curvature of these surfaces. These crests of contour give the crown its greatest labiolingual measurement. The crest of the curvature is at the cervical third F P THE PERMANENT MAXILLARY CENTRAL INCISOR MESIAL ASPECT The cervical line outlining the cementoenamel junction (CEJ) mesially on the maxillary central incisor curves incisally to a noticeable degree. This cervical curvature is greater on the mesial surface of this tooth than on any surface of any other tooth in the mouth. F P THE PERMANENT MAXILLARY CENTRAL INCISOR MESIAL ASPECT The labial outline of the crown from the crest of curvature to the incisal ridge is very slightly convex F P THE PERMANENT MAXILLARY CENTRAL INCISOR MESIAL ASPECT The lingual outline is convex at the point where it joins the crest of curvature at the cingulum; it then becomes concave at the mesial marginal ridge and slightly convex cingulum again at the linguoincisal ridge and the incisal edge. lingual fossa F P THE PERMANENT MAXILLARY CENTRAL INCISOR DISTAL ASPECT M D When looking at the central incisor from the distal aspect, it may be noted that the crown gives the impression of being somewhat thicker toward the incisal third. F P P F THE PERMANENT MAXILLARY CENTRAL INCISOR DISTAL ASPECT M D The curvature of the cervical line outlining the CEJ is less in extent on the distal than on the mesial surfaces. F P P F THE PERMANENT MAXILLARY CENTRAL INCISOR INCISAL ASPECT The crown conforms to a triangular outline F D M P THE PERMANENT MAXILLARY CENTRAL INCISOR INCISAL ASPECT From this aspect, the labial face of the crown is relatively broad and flat in comparison with the lingual surface, especially toward the incisal third. The outline of the lingual portion tapers lingually toward the cingulum THE PERMANENT MAXILLARY CENTRAL INCISOR INCISAL ASPECT The cervical portion of the crown labially is convex, although the arc described is broad. The cingulum of the crown makes up the cervical portion of the lingual surface. THE PERMANENT MAXILLARY CENTRAL INCISOR INCISAL ASPECT The mesiodistal calibration of the crown F at the labial line angles is greater than the same calibration at the lingual line angles. D M P THE PERMANENT MAXILLARY CENTRAL INCISOR INCISAL ASPECT The mesiodistal dimension is slightly F greater than labioligual dimension M-D width (8.5mm) D M F-L width (7.0 mm) P THE PERMANENT MAXILLARY CENTRAL INCISOR THE PERMANENT MAXILLARY CENTRAL INCISOR THE PERMANENT MAXILLARY CENTRAL INCISOR THE PERMANENT MAXILLARY CENTRAL INCISOR THE PERMANENT MAXILLARY LATERAL INCISOR Calcification & Eruption Schedule 2 2 Calcification begins 1 year Crown completed 4-5 years Eruption 8-9 years 7 10 Root completed 11 years 12 22 THE PERMANENT MAXILLARY LATERAL INCISOR The maxillary lateral incisor supplements the central incisor in function, the crowns bear a close resemblance. The lateral incisor is smaller in all dimensions except root length THE PERMANENT MAXILLARY LATERAL INCISOR Maxillary lateral incisors vary in form. If the variation is too great, it is considered a developmental anomaly. A common situation is to find maxillary lateral incisors with a nondescript, pointed form; such teeth are called peg-shaped laterals THE PERMANENT MAXILLARY LATERAL INCISOR In some individuals the lateral incisors are missing entirely, in these cases the maxillary central incisor may be in contact distally with the canine. THE PERMANENT MAXILLARY LATERAL INCISOR In some individuals the lateral incisors are missing entirely, in these cases the maxillary central incisor may be in contact distally with the canine. THE PERMANENT MAXILLARY LATERAL INCISOR The presence of a palatogingival groove in maxillary incisors may be a predisposing factor in localized periodontal disease This groove is also referred to as the palatoradicular groove. THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The labial outline of the Crown is trapezoidal with shortest side cervically D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The labial outline has more curvature, with a rounded incisal ridge and rounded incisal angles mesially and distally D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The tooth is relatively narrow mesiodistally , usually approximately 2 mm narrower than the central incisor. The crown on the average measures from 2 to 3 mm shorter cervic-oincisally than that of the 5 central incisor, although the root is usually as 9 long, if not somewhat longer, than that of the central incisor. 6.5 8.5 THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The mesial outline of the crown from the labial Aspect resembles that of the central incisor, with a more rounded mesioincisal angle D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The distal outline of the crown from the labial aspect is always more rounded D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The crest of contour mesially ( mesial contact area ) is usually at the point of junction of the middle and incisal thirds D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The crest of contour distally ( Distal contact area ) is more cervical, usually in the center of the middle third D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT The Cervical line curves toward the root (semicircular) same as central incisor but the curvature is more. D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT Root apex Distal curvature The root tapers evenly from the cervical line to a point approximately two-thirds of its length apically. In most cases, it curves sharply from this location in a distal direction and ends in a pointed apex. D M THE PERMANENT MAXILLARY LATERAL INCISOR LABIAL ASPECT Developmental groove : mesiolabial and distolabial: Two straight, shallow grooves separating the three labial lobes D M THE PERMANENT MAXILLARY LATERAL INCISOR PALATAL ASPECT Because of the crown lingual convergence (the tooth tapers toward the lingual) ,the Lingual surface is narrower than the labial surface M D THE PERMANENT MAXILLARY LATERAL INCISOR PALATAL ASPECT Lingual fossa: deep, triangular shaped and occupies 2/3 of lingual surface of the crown. M D THE PERMANENT MAXILLARY LATERAL INCISOR PALATAL ASPECT Cingulum is usually prominent limited to cervical 1/3 M D THE PERMANENT MAXILLARY LATERAL INCISOR PALATAL ASPECT Tendency toward deep Lingual pit or developmental groove within the lingual fossa, where it joins the cingulum. M D THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR CENTRAL INCISOR MESIAL ASPECT It is triangular with its base at the M M cervix but (Shorter and narrower than that of the central incisor) THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR CENTRAL INCISOR MESIAL ASPECT It is convex but less than central M M Incisor THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR CENTRAL INCISOR MESIAL ASPECT The crest of the curvature is at M M the cervical third THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR CENTRAL INCISOR MESIAL ASPECT The curvature of the cervical line is M M marked in the direction of the incisal ridge, although because of the small size of the crown the actual extent of curvature is less than that found on the central incisor. THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR CENTRAL INCISOR MESIAL ASPECT The heavy development of the incisal M M ridge accordingly makes the incisal portion appear somewhat thicker than that of the central incisor.. THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR CENTRAL INCISOR MESIAL ASPECT Root apex may have a Labial M M curvature THE PERMANENT MAXILLARY LATERAL INCISOR LATERAL INCISOR LATERAL INCISOR DISTAL ASPECT Similar to that of mesial aspect D M except 1. The crown appears thicker from distal aspect 2. Distal contact area is at the middle third 3. Palatogingival developmental groove may be seen on extending onto the root THE PERMANENT MAXILLARY LATERAL INCISOR INCISAL ASPECT F Similar to that of central incisor D M LATERAL INCISOR except 1. Labially. Crown is more convex P 2. The labiolingual dimension is slightly greater than the mesiodistal dimension F 3. The incisal ridge and the cingulum are more D M CENTRAL INCISOR prominent P THE PERMANENT MAXILLARY LATERAL INCISOR THE PERMANENT MAXILLARY LATERAL INCISOR THE PERMANENT MAXILLARY LATERAL INCISOR THE PERMANENT MAXILLARY LATERAL INCISOR  The maxillary lateral incisor is smaller than the maxillary central incisor in all dimensions except which of the following? A. Crown length B. Root length C. Mesiodistal diameter of crown D. Curvature of the mesial cervical line  Which of the following structures is not considered a border of the lingual fossa of a maxillary central incisor? A. Distal marginal ridge B. Mesial marginal ridge C. Cingulum D. Labioincisal edge  The root of the permanent maxillary central incisor is complete by what age? A. 9 YEARS B. 10 YEARS C. 11YEARS D. 12 YEARS  Which of the following teeth has a variant in form known as being “peg shaped”? A. Maxillary central incisor B. Maxillary lateral incisor C. Mandibular central incisor D. Mandibular lateral incisor  Which of the following surfaces demonstrates the greatest curvature of the cervical line? A. #7 distal B. #7 mesial C. #8 distal D. #8 mesial