Permanent Mandibular Molars PDF

PERMANENT mandibular molars Dr. Sandeep Gupta Oral Pathologist Buccal Aspect Of Mandibular Molars Crown Shape – The crowns of mandibular molars are wider mesiodistally than high cervico-occlusally (greatest extent on first molars) 3 2 1 Buccal Aspect Of Mandibular Molars First Molar Cusps – The mesi...

PERMANENT mandibular molars Dr. Sandeep Gupta Oral Pathologist Buccal Aspect Of Mandibular Molars Crown Shape – The crowns of mandibular molars are wider mesiodistally than high cervico-occlusally (greatest extent on first molars) 3 2 1 Buccal Aspect Of Mandibular Molars First Molar Cusps – The mesiolingual cusp is the highest and widest – The first molar has the largest mesiodistal dimension of any tooth – First molars usually possess three buccal cusps S M L Buccal Aspect Of Mandibular Molars DB Line angle First Molar Cusps – The mesiobuccal is the largest, widest, and highest cusp on the buccal side – The distobuccal cusp is slightly smaller, shorter, and may be sharper than the mesiobuccal – Distal cusp is on the DB line angle and is the smallest of the five cusps Buccal Aspect Of Mandibular Molars First Molar Cusps 2nd highest – The distolingual cusp is the second highest cusp when the tooth is oriented vertically – Even though the lingual cusps are higher than the buccal cusps, clinically the lingual cusp tips are at a lower level than the buccal due to the lingual tilt of the tooth Buccal Aspect Of Mandibular Molars MB groove Grooves Of The First Molars Buccal Pit – The mesiobuccal groove separates the mesiobuccal and distobuccal cusp – There may be a deep pit at the cervical end of this groove – This pit can be a site of caries Buccal Aspect Of Mandibular Molars DB groove Grooves Of The First Molar – The distobuccal groove separates the distobuccal cusp from the distal cusp – It is shorter than the MB groove and not frequently pitted D Buccal Aspect Of Mandibular Molars Second Molar Cusps – Four cusps are present on lower second molars – MB cusp is usually wider mesiodistally than the DB cusp – The lingual cusp tips are usually visible from the buccal aspect M D M Buccal Aspect Of Mandibular Molars Buccal groove Grooves Of The Second Molar – The buccal groove separates the MB cusps from the DB cusp – May end in the middle of the buccal surface in a pit Buccal Aspect Of Mandibular Molars Proximal Contacts – Same as all molars – Mesial: Junction of the occlusal and middle thirds – Distal: Middle third of crown #31 Buccal Aspect Of Mandibular Molars #30 Taper To The Cervical – There is proportionally more tapering of the crown from contact areas to the cervical line on first molars than second molars because of the bulge of the distal cusp Buccal Aspect Of Mandibular Molars Absent 1/5 of the time Variations In Mandibular Molar Crowns – The distal cusp is absent. – A four-cusp molar may not always be a second molar - rely on tooth position to aid in determination Roots Of Mandibular Molars Both mandibular first and second molars have two roots (one mesial and one distal) Both roots are nearly twice as long as the crown Roots Of Mandibular Molars Root depression The root bifurcation of a mandibular first molar is near the cervical line A depression exists between the cervical line and bifurcation The root trunk relatively short (shorter than lower second molars) Short root trunk Roots Of Mandibular Molars Note distal bend in root Roots of first molars are widely separated Second molars have more parallel roots Roots may possess a distal curve in the apical portion Roots Of Mandibular Molars The distal root is straighter than the mesial root and may possess a pointed apex The apex of the mesial root may be in line with the mesiobuccal groove as the root is bend in middle. #30 Lingual Aspect Of Mandibular Molars Crown Shape From The Lingual – Mandibular first and second molar crowns taper to the lingual – This lingual taper is more evident in first molars – The lingual cusps are longer and more pointed than the buccal cusps ML Lingual Aspect Of Mandibular Molars Crown Shape From The Lingual – The mesiolingual cusp is usually longer and wider (slightly) than the distolingual cusp DL #30 Lingual Aspect Of Mandibular Molars Grooves – The lingual groove separates the mesiolingual cusp from the distolingual cusp – Terminates in the occlusal third with no pit Lingual Aspect Of Mandibular Molars Cervical Line – The CEJ is relatively flat mesiodistally – Can dip cervically between the roots over the bifurcation (similar to buccal) – A depression can be seen between the cervical line and the bifurcation Mesial Roots Of Mandibular Molars From The Lingual The roots are narrower on the lingual aspect than the buccal Proximal Aspect Of Mandibular Molars Crown Shape From The Proximal – Appear relatively short occlusocervically compared to faciolingual dimension – The crowns are tilted lingually on the root base – The buccal outline is convex in the cervical third Proximal Aspect Of Mandibular Molars #30 Crest Of Curvature – The height of contour on the buccal surface is within the cervical third – On molars this buccal bulge is called the buccal cervical ridge – It is more prominent on second molar than first molars #30 Proximal Aspect Of Mandibular Molars Cusp Height – The lingual cusps are more conical and pointed than the buccal – They are the largest of the four to five cusps #30 Distal Proximal Aspect Of Mandibular Molars #31 Distal Distal Tilt – Due to the distal tilt of the crown and the sloping of the occlusal surface, most of the occlusal surface and all cusps can be seen from the distal #30 Distal Proximal Aspect Of Mandibular Molars #31 Distal Taper To The Distal – On both first and second molars the crown is more narrow on the distal than the mesial – Can see some of the buccal and lingual surface from the distal due to this taper Proximal Aspect Of Mandibular Molars Cervical Line – The mesial CEJ of both first and second molars slopes occlusally from buccal to lingual – The distal cervical line is nearly straight Occlusal Aspect Of Mandibular Molars Lingual Inclination – Due to lingual inclination a considerable portion of the buccal aspect can be seen from this view – The molars are wider mesiodistally than faciolingually Occlusal Aspect Of Mandibular Molars D M M Shape: Rectangular Or Pentagon – The second molar is roughly rectangular – The first molar with the distal cusp is more like a pentagon – The two mesial cusps are larger than the two distal cusps D Occlusal Aspect Of Mandibular Molars D M M Taper To The Distal And Lingual – The crown is narrower buccolingually on the distal than the mesial – The crown is narrower mesiodistally on the lingual than the facial D Occlusal Aspect Of Mandibular Molars Ridges – On both first and second molars the MB and ML cusp’s triangular ridges form a transverse ridge – The same is true for the DB and DL cusps – Since lingual cusps are taller, they possess longer triangular ridges than the buccal Occlusal Aspect Of Mandibular Molars Fossae – Mandibular molars possess three fossae, a large central fossa, a smaller mesial, and the smallest distal fossa – Each or all may possess a pit MB Groove DB Groove Occlusal Aspect Of Mandibular Molars Grooves: First Molar – The central groove is more zigzag – There are two buccal grooves instead of one found on lower second molars Occlusal Aspect Of Mandibular Molars Grooves: Second Molar – Groove is simpler than first and resembles a cross – Central groove is straighter than that of the first molar – Buccal and lingual grooves are usually continuous Mandibular Third Molars #32 Distal #32 Buccal Shape And Relative Size – Shortest of mandibular teeth – Crown may resemble a first or second molar – Generally have bulbous crowns Mandibular Third Molars Cusp Size – Lingual cusps are the longest and largest, with ML being biggest Grooves – Irregular groove pattern with multiple supplemental grooves Mandibular Third Molars Roots #32 Lingual #32 Mesial – The two roots tend to be short and are often fused – If the roots are separate the root trunk will be long – Can possess one or more extra roots Mandibular 1st Molar Chronology Mandibular 2nd Molar Chronology Mandibular 3rd Molar Chronology Maxillary 1st Molar Chronology Maxillary 2nd Molar Chronology Maxillary 3rd molar Chronology Thank You