Permanent Mandibular Incisors PDF

PERMANENT MANDIBULAR INCISORS PERMANENT MANDIBULAR INCISORS * The mandibular incisors are four in number. PERMANENT MANDIBULAR INCISORS The mandibular central incisors are centered in the mandible, one on either side of the median line, with the mesial surface of each in contact with the mesial su...

PERMANENT MANDIBULAR INCISORS PERMANENT MANDIBULAR INCISORS * The mandibular incisors are four in number. PERMANENT MANDIBULAR INCISORS The mandibular central incisors are centered in the mandible, one on either side of the median line, with the mesial surface of each in contact with the mesial surface of the other. D M D PERMANENT MANDIBULAR INCISORS The right and left mandibular lateral or second incisors are distal to the central incisors. D M D PERMANENT MANDIBULAR INCISORS The mandibular incisors have smaller mesiodistal dimensions than any of the other teeth. The central incisor is somewhat smaller than the lateral incisor, which is the reverse of the situation in the maxilla. D M D M PERMANENT MANDIBULAR INCISORS Are the first permanent teeth to erupt 6-7 years  PERMANENT MANDIBULAR INCISORS The crowns of these teeth exhibit lingual inclination over the root base which can be appreciated from proximal aspects. PERMANENT MANDIBULAR CENTRAL INCISORS Calcification & Eruption Schedule 1 1 Calcification begins 3-4 Months Crown completed 4-5 years Eruption 6-7 years 24 25 Root completed 9 years 41 31 PERMANENT MANDIBULAR CENTRAL INCISORS Generally the mandibular central incisor is the smallest tooth in the dental arches D M PERMANENT MANDIBULAR CENTRAL INCISORS The crown has little more than half the mesio-distal diameter of the maxillary central incisor 5mm MX central incisor ? D M  PERMANENT MANDIBULAR CENTRAL INCISORS The single root is very narrow mesiodistally and corresponds to the narrowness of the crown, although the root and crown are wide labiolingually. 6 5 L L D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT Trapezoid with shortest side cervically D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT The crown labial aspect is ordinarily smooth, with a flattened surface at the incisal third, the middle third is more convex, narrowing down to the convexity of the root at the cervical portion. D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT The incisal ridge of the crown is straight and is at approximately a right angle to the long axis of the tooth. NB: A newly erupted tooth shows mamelons on the incisal ridge D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT Usually the mesial and distal outlines of the crown make a straight drop downward from the incisal angle to cervical area D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT The mesioincisal angle is sharp and at right angle D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT Mesial contact area is at the incisal third D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT The DISTOINCISAL angle is sharp and at right angle D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT Distal contact area is at the incisal third (at the same level) Bilaterally symmetrical crown D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT DEVELOPMENTAL depressions Are not normally present Occasionally, there are very faint ( fewest ) depressions which only occur near the incisal margin D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT The outlines of the mesial and distal roots are straight with the mesial and distal outlines of the crown down to the apical portion D M PERMANENT MANDIBULAR CENTRAL INCISORS LABIAL ASPECT The apical third of the root terminates in a small pointed taper, in most cases curving distally. D M PERMANENT MANDIBULAR CENTRAL INCISORS LINGUAL ASPECT Slight concavity Flat The lingual surface of the crown is smooth, with a very slight concavity at the incisal third, Convex then becomes flat and then convex as progresssion is made from the incisal third to the cervical third. M D PERMANENT MANDIBULAR CENTRAL INCISORS LINGUAL ASPECT No developmental lines ‡Cingulum size is the least developed (shared with mandibular lateral incisor) M D PERMANENT MANDIBULAR CENTRAL INCISORS LINGUAL ASPECT The outlines and surfaces of the mandibular incisors are regular and symmetric.) M D PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT It is triangular with its base at the cervix L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The curvature labially and lingually above the cervical line is less than that found on maxillary incisors L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT LINGUAL The incisal ridge is rounded or worn flat, and its center is usually lingual to the center of the root L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT LINGUAL The crown appears to be inclined lingually; this mandibular teeth feature to facilitate normal overiet L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The outline of the labial face of the crown is straight above the cervical curvature , sloping rapidly from the crest of curvature to the incisal ridge. L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The lingual outline of the crown is a straight line inclined labially for a short distance above the smooth convexity of the cingulum cingulum L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The lingual outline of the crown is a straight line inclined labially for a short distance above the smooth convexity of the cingulum cingulum the straight outline joins a concave line at the middle third of the crown, L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The lingual outline of the crown is a straight line inclined labially for a short distance above the smooth convexity of the cingulum cingulum the straight outline joins a concave line at the middle third of the crown, which extends upward to join the rounded outline of a narrow incisal ridge. L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The curvature of the cervical line representing the cementoenamel junction (CEJ) on the mesial surface is marked, curving incisally approximately one-third the length of the crown L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The root outlines from the mesial aspect are straight with the crown outline from the cervical line. L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT convex and smooth The mesial surface of the crown is convex and broader and flatter smooth at the incisal third and becomes quite flat broader and flatter at the middle third cervical to the contact area; it then becomes quite flat, with a tendency toward concavity immediately below the middle third of the crown and above the cervical line L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The root outlines from the mesial aspect are straight with the crown outline from the cervical line. so that the root diameter is uniform through the cervical third and part of the middle third L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT The root outlines from the mesial aspect are straight with the crown outline from the cervical line. the outline of the root begins to taper in the middle third area, tapering rapidly in the apical third to either a bluntly rounded or a pointed root end. L L PERMANENT MANDIBULAR CENTRAL INCISORS MESIAL ASPECT Most of roots have a broad developmental depression for most of the root length. The depressions are usually deeper at the junction of the middle and apical thirds L L PERMANENT MANDIBULAR CENTRAL INCISORS DISTAL ASPECT The cervical line representing the CEJ curves incisally about 1 mm less on the distal aspect than on the mesial aspect. 3mm 2mm L MESIAL ASPECT L DISTAL ASPECT L PERMANENT MANDIBULAR CENTRAL INCISORS DISTAL ASPECT The developmental depression on the distal surface of the root may be more marked, with a deeper, better-defined developmental groove at its center. L MESIAL ASPECT L DISTAL ASPECT L PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT L The Oval labiolingually M D L PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT L The incisal aspect illustrates the bilateral symmetry of the mandibular central incisor). M D The mesial half of the crown is almost identical with the distal half. L PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT L Because of the crown lingual inclination, most of the labial surface is seen from this aspect M D L PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT L The incisal edge is almost at right angles to a line bisecting the crown labiolingually. M D L PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT L The labiolingual diameter is always greater than mesiodistal diameter. M D L PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT Labial The labial surface of the crown is wider mesiodistally than the lingual surface M D Lingual PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT Labial The cingulum forms a smaller convex M D Lingual PERMANENT MANDIBULAR CENTRAL INCISORS INCISAL ASPECT Labial The labial surface of crown at incisal third is convex , while the lingual surface of the crown at M D incisal third is concave Lingual PERMANENT MANDIBULAR LATERAL INCISORS Calcification & Eruption Schedule 2 2 Calcification begins 3-4 Months Crown completed 4-5 years Eruption 7-8 years 26 23 Root completed 10 years 42 32 PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT Mandibular lateral incisor is very similar to the mandibular central in form as the two teeth function as a team It is slightly larger than the mandibular central incisor (unlike the case of maxillary incisors where the lateral is smaller than the central incisor) PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT Similar to that central incisor except The crown is not bilaterally symmetrical; the crown distal half is slightly larger The mesiodistal width of crown is approximately 1 mm more PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT trapezoid with shortest side cervically D M PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT Incisal ridge straight but may appear to slope downward in a distal direction. D M PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT MESIOINCISAL angle is sharp (90°), DESTOINCISAL angle more rounded. D M PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT The contact areas are near the incisal ridges mesially and distally Some times, the distal contact area is more toward the cervical than the mesial contact area D M PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT Mesial crown outline is straight, but distal has more curvature (very slight convexity). D M PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT A tendency toward a deeper concavity immediately above the cervical line on the distal surface of the mandibular Lateral incisor. D M PERMANENT MANDIBULAR LATERAL INCISORS LABIAL ASPECT NB: The crown mesial and distal outlines are continuous with that of the root D M PERMANENT MANDIBULAR LATERAL INCISORS LINGUAL ASPECT Similar to that central incisor except Lingual surface is wider mesiodistally than that of the central incisor. PERMANENT MANDIBULAR LATERAL INCISORS LINGUAL ASPECT Similar to that central incisor except Marginal ridges, cingulum and lingual fossa are more prominent PERMANENT MANDIBULAR LATERAL INCISORS PROXEMAL ASPECT It is triangular with its base at the cervix MESIAL ASPECT DISTAL ASPECT PERMANENT MANDIBULAR LATERAL INCISORS PROXEMAL ASPECT The mesial side of the crown is often longer than the distal side; this causes the incisal ridge, which is straight, to slope downward in a distal direction MESIAL ASPECT DISTAL ASPECT PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT The incisal ridge is at an angle to the line bisecting the tooth labiolingually rather than being perpendicular to it INCISAL ASPECT PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT The incisal ridge is at an angle to the line bisecting the tooth labiolingually rather than being perpendicular to it INCISAL ASPECT PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT LABIAL The incisal edge is not at approximate right angles to a line M D bisecting the crown which gives the crown of the mandibular lateral incisor the appearance Distoincisal of angle of mandibular permanent central incisor is: being twisted slightly on its root LINGUAL base a. Acute angled b. Right angled c. Obtuse angled d. None of the above PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT LABIAL The incisal edge is not at approximate right angles to a line M D bisecting the crown which gives the crown of the mandibular lateral incisor the appearance In mandibular of central incisor, the mesial and permanent being twisteddistal contacton slightly area itsare: root LINGUAL base a. At the same level b. At different levels c. Absent one side d. Absent on both the sides PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT LABIAL The incisal edge is not at approximate right angles to a line M D bisecting the crown which gives the crown of the mandibular lateral incisor the appearance In mandibular permanent of central incisor, the labiolingual being twisted dimension slightlyis:on its root LINGUAL basea. Always smaller than mesiodistal dimension b. Always greater than mesiodistal dimension c. Both are exactly same d. None of the above PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT LABIAL The incisal edge is not at approximate right angles to a line M D bisecting the crown which gives the crown of the mandibular lateral incisor the appearance of The smallest tooth in permanent dentition is: being twisted slightly on its root LINGUAL base b. Mandibular permanent lateral incisor a. Maxillary permanent lateral incisor c. Mandibular permanent central incisor d. Maxillary permanent central incisor PERMANENT MANDIBULAR LATERAL INCISORS INCISAL ASPECT LABIAL The incisal edge is not at approximate right angles to a line M D bisecting the crown which gives the crown of the mandibular lateral incisor the appearance of The crown of mandibular permanent central incisor is: being twisted slightly on its root LINGUAL basea. Bilaterally asymmetrical from labial and b. Bilaterally symmetrical from labial, lingual aspects lingual and incisal aspects c. Bilaterally symmetrical from all aspects d. Bilaterally asymmetrical from all aspects