MANDIBULAR MOLARSMANDIBULAR FIRST MOLAR
Eruptions time: 6-7 years Root Completed: 9-10 yearsNormally, the mandibular first molar is the largest tooth in the mandibular arch. It has five well-developed cusps two buccal, two lingual and one distal. Two root one mesial and one distal.
Buccal AspectLingual Aspect
1-Three cusps may be seen: two lingual cusps and the lingual portion of the distal cusp. The two lingual cusps are pointed.
2-The distolingual cusp is almost as wide mesiodistally as the mesiolingual cusp.
3-The distal cusp is at a lower level than the mesiolingual cusp.Mesial Aspect
Two cusps and one root only are to be seen: the mesiobuccal and mesiolingual cusps and the mesial root.
Distal Aspect1-We see more of the tooth from the distal aspect because the crown is shorter distally than mesially and the buccal and lingual surfaces of the crown converge distally.
2-The distal root is narrower buccolingually than the mesial root.
Occlusal Aspect1-The mandibular first molar is somewhat hexagonal from the occlusal aspect.
2-The crown measurement is 1 mm or greater mesiodistally than buccolingually.
3-It must be remembered that the opposite arrangement is true of the maxillary first molar.
Mandibular Second MolarEruptions time: 11-13 years Root Completed: 14-15 years
Buccal aspect1- the crown is shorter and narrower mesio-distally than the first molar.
2-there is one developmental groove dividing the M-B and D-B cusps which are equal in size.
3- the CL points sharply toward the root bifurcation.
4- two roots that are less broad and close together.
Lingual aspectDifferences between the man. Second molar and man. First molar:
1- the crown and root of man. Second molar converge lingually.
2- the M-D calibration lingually is greater than that of first molar.
3- the curvatures M and D on the crown are more noticeable from the lingual aspect.
4- only the lingual cusps are in view.
Mesial aspect1- the cervical ridge buccally less pronounced and the occlusal surface is constricted bucco-lingually.
2- the cervical line shows no curvature.
3- the two roots may be seen from this aspect.
Distal aspect1- absene of distal cusp and disto-buccal groove.
2- most of the buccal surface can be seen from this aspect.
Occlusal aspect1- it is roughly rectangular.
2- the central groove is in the center.
3- the lingual and buccal developmental grooves meeting the central developmental groove at right angle.
Mandibular third molarEruptions time: 17-21 years Root Completed: 18-25 years
Buccal aspect1- the crown is wider mesio-distally than at the cervix.
2- the buccal cusps are short and rounded.
3- the crest of contour mesially and distally is located more than half the distance from cervical line to tips of cusps.
4- the third molar has two roots, one mesial and one distal.
Lingual aspectThe mandibular third molar, when well developed, corresponds closely to the form of the second molar except for size and root development.
Mesial aspectFrom the mesial aspect, it resembles the mandibular second molar except in dimensions. The roots are shorter, with the mesial root tapering more from cervix to apex.
Distal aspectThe anatomic appearance of the distal portion is like that of the second molar except for size. The distal root appears small when compared with the crown portion.
Occlusal aspectThe occlusal aspect is similar to that of the second man. Molar, there is a tendency toward a more rounded outline and a smaller bucco-lingual measurement distally.
First molarSecond molar
third molarFirst molar Second molar