Mandibular central & lateral 23-24 S.Copy (2).pdf

Mandibular Permanent Central Incisor Mandibular Permanent Central Incisor # 31 , # 41 ( FDI ) # 24 , # 25 ( Universal) Prof. Hisham Othman 2023-24  Mandibular Permanent Central Incisor Mandibular Perm...

Mandibular Permanent Central Incisor Mandibular Permanent Central Incisor # 31 , # 41 ( FDI ) # 24 , # 25 ( Universal) Prof. Hisham Othman 2023-24  Mandibular Permanent Central Incisor Mandibular Permanent Central Incisor  Mandibular Permanent Central Incisor Learning outcomes: Ø Labial Aspect Ø Lingual aspect Ø Mesial aspect Ø Distal aspect Ø Incisal aspect Ø Anomalies Each aspect has the following items Labial and Lingual aspects: Proximal aspects: Ø Geometric shape of the crown Ø Geometric shape of the crown Ø Mesial / Distal outlines Ø Labial / lingual outlines Ø Contact area locations Ø Crest of curvatures (contoures) Ø Incisal angles Ø Incisal edge Ø Cervical line Ø Cervival line  Mandibular Permanent Central Incisor Ø It is the smallest tooth in the dental arch Ø Smallest mesiodistal dimensions than any of other teeth Ø It shows uniform development with bilateral symmetry with few instances of malformation  Mandibular Permanent Central Incisor Ø Labial Aspect Ø The outline of the tooth is regular & straight Ø Taper evenly from the sharp mesial and distal incisal angles to the apical portion of the root  Mandibular Permanent Central Incisor Ø MCA and DCA located at the same level within the incisal third ØThe mesial and distal outlines are straight ØTheincisal outline Straight and at right angle to the long axis of the tooth  Mandibular Permanent Central Incisor Ø Mamelons Ø Smooth with few traces of developmental lines Ø The labial surface is Flat at the incisal third, convex at the middle third and more convex at the cervical third  Mandibular Permanent Central Incisor The Root Ø Regular and convex labially Ø Taper evenly to the pointed apex j Ø The apical third curves distally in most cases Mesial Distal  Mandibular Permanent Central Incisor Ø Labial Aspect Distal Mesial  Mandibular Permanent Central Incisor Ø Lingual aspect Ø The lingual surface Smooth marginal ridges and shallow lingual fossa Ø Slight concave at the incisal third, flat at the middle and convex at the cervical third  Mandibular Permanent Central Incisor Ø Lingual aspect ØThe cervical line is placed 0.5 mm. apically, making the crown longer on the lingual side +0.5 mm  Mandibular Permanent Central Incisor Ø Mesial aspect Ø Labial outline Straight from the crest of Labial Lingual curvature at the cervical third to the incisal ridge Ø Lingual outline Smooth convexity at the cingulum, concave at the middle third and extends to join the round incisal ridge Ø Incisal ridge Rounded and lingual to the center of the root (Why ?)  Mandibular Permanent Central Incisor Ø Mesial aspect Ø Mesial contact area is located within the incisal third Ø Root outlines Labially and lingually are straight and parallel in the cervical and middle third, then taper to rounded apex Ø A broad developmental depression at the root surface ( Function ?)  Mandibular Permanent Central Incisor Labial Lingual Ø Mesial aspect  Mandibular Permanent Central Incisor Ø Distal aspect Ø The CL. is shallower Ø Marked development depression with deep developmental groove on the root surface Labial  Mandibular Permanent Central Incisor Ø Incisal aspect Ø The incisal edge is straight and located lingually to a line bisecting the crown labiolingually Ø Rounded incisal edge Ø lingual convergence Ø Bilateral symmetry Ø Wider labiolingual than mesiodistally  Mandibular Permanent Central Incisor Dental Anatomy Manual/ 20-21 Permanent Mandibular Central Incisor Disto-incisalLabial Aspect Incisal Ridge Lingual Aspect Mesio-incisal Labial angle angle Mesial Aspect Distal Aspect DCA MCA Mesial Distal Incisal Ridge DCA Mesial Lingual Distal MCA Fossae Marginal Marginal Distal Ridge Ridge Mesial Marginal Marginal Lingual Ridge Ridge Incisal Aspect Cingulum Cervical Lingual crest Ridge Labial crest of curvature of curvature Cervical line Cingulum Distal Mesial Distal Development Mesial Distal Mesial Depression Development Depression Lingual Labial Labial 14 Lingual  Mandibular Permanent Lateral Incisor Mandibular Permanent Lateral Incisor # 32 , # 42 ( FDI ) # 23 , # 26 ( Universal) Prof. Hisham Othman 2023-24  Mandibular Permanent Lateral Incisor Mandibular Permanent Lateral Incisor  Mandibular Permanent Lateral Incisor Ø Labial Aspect Ø Slightly larger than the lower central incisor Ø The crown has fan shape ØThe mesial side is longer than the MCA distal causing the incisal ridge to DCA slope cervically in a distal direction ØThe DCA is slightly cervical in the incisal third than the MCA  Mandibular Permanent Lateral Incisor Incisal Aspect  Mandibular Permanent Lateral Incisor Incisal Aspect  Mandibular Permanent Lateral Incisor ØThe incisal ridge is not at right angle to the long axis of the tooth. tear Ø The crown follows the mandibular arch curve, while the root axis remains parallel to the central incisor. Ø This arrangement gives the crown of the lateral the appearance of being twisted on its base distolingually  Mandibular Permanent Lateral Incisor Anomalies Macrodontia Microdontia Fusion  Mandibular Permanent Lateral Incisor Fusion  Dental Anatomy Manual/ 20-21 Permanent Mandibular Lateral Incisor Labial Aspect Incisal Ridge Disto-incisal Lingual Aspect Mesio-incisal Labial angle angle Distal Aspect Mesial Aspect DCA MCA Mesial Distal Lingual Distal DCA Fossae Marginal Mesial Ridge Marginal Distal Ridge Mesial Lingual Marginal Marginal Incisal Aspect Ridge Ridge Cingulum Cervical Lingual crest Ridge of curvature Labial crest Cervical line of curvature Cingulum Distal Mesial Development Depression Distal Mesial Development Depression Distal Mesial Lingual Labial Labial Lingual 17  Pulp Morphology Mandibular Central Incisor  Pulp Morphology Mandibular Central Incisor ØThe pulp chamber has two pulp horns directed toward the incisal angles Ø Pulp chamber and root canal are constricted cervically and narrow at the apex Ø Occasionally, there is a distal inclination at the apex with lateral position of the apical foramen Labial Aspect  Pulp Morphology Mandibular central incisor The pulp chamber is pointed incisally taking out the 0 general outline of the crown Ø The root canal remains wide until the middle third, then it tapers apically and open by single foramen Ø There may be two root Proximal Aspect two separate openings J canals, labial and lingual with  Pulp Morphology Root Cross section Ø Oval and wider labiolingually Mandibular central incisor Mandibular Central and Lateral Incisor