Please answer the following: Describe the overall anatomy of the crown and root
ID: 3513942 • Letter: P
Question
Please answer the following: Describe the overall anatomy of the crown and root of the maxillary molars. Describe the overall anatomy of the crown and root of the mandibular molars. What are the differences between the upper and lower 1st molars? What are the differences between the upper and lower 2nd molars? Explain grooves and pits of the maxillary and mandibular molars. What are the developmental disturbances that can affect 3rd molars? How can you distinguish the right maxillary 1st molar from the left? At what ages do the molars erupt? How could you tell the difference between a maxillary 1st and maxillary 2nd molar? Where are the furcations on mandibular molars and maxillary molars? What is the order of cusps from largest to smallest on # 19 and #30? What is the order of cusps from largest to smallest on #3 and #14? What is an oblique ridge and where would you find it? What tooth numbers are associated with 3rd molars? What tooth numbers are associated with 2nd molars?
Explanation / Answer
Answer:
Overall crown and root anatomy of the maxillary molars:
Maxillary molars:
The occlusal surfaces of the maxillary molar teeth are roughly rhomboidal in shape and more pronounced in the second molar to heart-shaped in the third molar. With greatest buccolingual diameter for the first molars followed by the second and the third. A typical maxillary molar has Four cusps namely, the Mesiobuccal, distobuccal, mesiolingual(largest), distolingual. 60% of the population has an additional cusp on the first molar called the cusp of carabelli on the mesial half of the mesiolingual cusp.
The distolingual cusps becomes progressively smaller in the second and third maxillary molars, often seen disappearing onto the third molars. It shows three roots namely the Mesiobuccal, distobuccal and palatal; the palatal being the longest root and distobuccal being the shortest root.The third molar is characterized by the presence of fused roots.
The occlusal aspect of the molars has oblique ridges running between the mesiolingual cusp to the distobuccal cusp, Major, and minor fossae, The mesial and distal marginal ridges, a central fossa and developmental grooves. These structures can be seen more pronounced in first molars than in the rest.
Mandibular molars:
The mandibular first molar shows the greatest mesiodistal diameter of all the teeth. They have five cusps namely, the mesiobuccal( widest mesiodistally), distobuccal, mesiolingual, distolingual and distal cusps. the distal cusp is absent in second and third molars.Each mandibular molar has two roots; a mesial and a distal root. third and second molars may show fused roots.
The crowns are roughly quadrilateral somewhat longer mesiodistally than buccolingually and are shorter cervico-occlusally.The crowns have developmental grooves, triangular fossae, central fossa on the occlusal aspect of the teeth.
Comparison between maxillary first and mandibular first molars.
Mesial furcation is 3mm above the cervical line
Buccal furcation is 4mm above and distal furcation is 5 mm above the cervical line
5 developmental grooves
2 major fossae- central and distal
2 minor fossae- mesial and distal triangular fossa
4 cusp ridges
1 oblique ridge
1 Major central fossa
2 minor fossae
4 developmental grooves
5 cusp ridges
Eruption timings of Molar teeth
Maxillary
Mandibular:
Features Maxillary first molar Mandibular first molar cusps Mesiolingual- largest, mesiobuccal, distobuccal, distolingual, cusp of carabelli Mesiobuccal - largest, mesiolingual, distolingual, distobuccal, distal. No of roots 3 roots, mesiobuccal, distobuccal and palatal 2 roots, mesial and distal. FurcationsMesial furcation is 3mm above the cervical line
Buccal furcation is 4mm above and distal furcation is 5 mm above the cervical line
Buccal furcation is 3mm above the cervical line and lingual furcation is 4mm above. Occlusal anatomy5 developmental grooves
2 major fossae- central and distal
2 minor fossae- mesial and distal triangular fossa
4 cusp ridges
1 oblique ridge
1 Major central fossa
2 minor fossae
4 developmental grooves
5 cusp ridges
Oblique ridge formed by the mesiolingual and distobuccal cusps. -