Anatomy of Mandibular First Molar - Tooth Morphology — Transcript

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9. 0:16for which is given here above
10. 0:19so let's begin
11. 0:21mandibular first molar is the sixth
12. 0:23earth from the midline
13. 0:25it is the largest earth in the
14. 0:27mandibular arch
15. 0:29the truth has five well-developed curves
16. 0:31and has two roots a measle and a distal
17. 0:34root
18. 0:36both measle and distal roots are broad
19. 0:39bucco lingually between the two roots
20. 0:41the mesial root is broader of the two
21. 0:43let's study all five aspects of the turt
22. 0:46in detail
23. 0:48from the buccal aspect the crown of the
24. 0:50turt is roughly trapezoidal in shape
25. 0:52all five buccal and lingual curses of
26. 0:55the turt are visible from this aspect
27. 0:58the buccal curse are the mesiobuccal the
28. 1:00dystrobuccil and the distal curse
29. 1:03the two lingual curves which are the
30. 1:05mesolingual and the distrolingual curse
31. 1:08are also visible because of its higher
32. 1:10position and pointed curved tips
33. 1:15two grooves can be observed on the
34. 1:16buccal aspect called the mesiobuccal
35. 1:19developmental groove located in between
36. 1:21the mesial buccal and the dystrophical
37. 1:23lobe and the dystrophical developmental
38. 1:25groove located in between the
39. 1:27distrobuccal and the distal lobe of the
40. 1:29turret
41. 1:31the mesio buccal groove is the shortest
42. 1:33of the two
43. 1:34the tips of all three buccal curses are
44. 1:37flat and this flatness is another reason
45. 1:40for the well-observed lingual curves
46. 1:42from the suspect
47. 1:44the mesial buccal curve is the largest
48. 1:46curve and the distal curve is the
49. 1:47smallest of all five curses
50. 1:50the mesial contact area is located at
51. 1:53the junction of the occlusal
52. 1:55and the middle third
53. 1:57while the distal contact area is located
54. 1:59in the middle of the middle third
55. 2:01the cervical line is curved evenly
56. 2:03towards the root
57. 2:15the measle outline of the crown is
58. 2:16convex from the cervical line up to the
59. 2:19mesial contact area while the distal
60. 2:21outline is almost straight
61. 2:24at the point where the developmental
62. 2:26grooves end a developmental depression
63. 2:28is noticeable which runs in a mesodictal
64. 2:31direction
65. 2:32and due to this developmental depression
66. 2:34a cervical ridge is evident below the
67. 2:36depression at the buccal surface
68. 2:40the cervical ridge may also show a
69. 2:42smooth developmental depression in it
70. 2:45which runs cervically and joins with the
71. 2:47developmental concavity just below the
72. 2:50cervical line at the bifurcation area or
73. 2:53at the root trunk buckley
74. 2:55the point of bifurcation of the true
75. 2:57roots is located approximately 3 mm
76. 3:00below the cervical line where it
77. 3:02bifurcates into the measle and distal
78. 3:04roots
79. 3:06both measle and distal roots are curved
80. 3:08towards the distal
81. 3:12on both measles and distal roots a
82. 3:14developmental depression is present
83. 3:16which is elongated in shape
84. 3:18these depressions provide a strong
85. 3:20anchorage for the mandibular first molar
86. 3:24from the lingual aspects the two mesial
87. 3:26lingual and the distrolingual curves are
88. 3:28visible
89. 3:32the buccal curves cannot be seen due to
90. 3:34the high crystal ridges and the pointed
91. 3:36curved tips of the two lingual curves
92. 3:39the mesiolingual curve is the wider of
93. 3:41the two lingual curves
94. 3:43the custard slopes of the mesio-lingual
95. 3:46and the distrolingual curves joins at an
96. 3:48obtuse angle of approximately 100
97. 3:51degrees at the curved tip
98. 3:53the lingual developmental groove
99. 3:55separates the mesial lingual and the
100. 3:56distrolingual lobes of the truth on the
101. 3:58lingual aspect this groove is shorter
102. 4:01than the grooves present on the buccal
103. 4:02aspect of the trunk
104. 4:04the distrolingual curve is at a lower
105. 4:06level than the mesiolingual curse the
106. 4:09location of contact areas are just like
107. 4:11that found on the buccal aspect of the
108. 4:13truck
109. 4:14the measle outline is convex all the way
110. 4:16from the cervical line up to the mesial
111. 4:18marginal ridge while the distal outline
112. 4:21is straight below the contact area
113. 4:24part of the measle and distal surfaces
114. 4:26of the crown and root trunk may be seen
115. 4:28from this aspect because the measle and
116. 4:31distal sides converge lingually
117. 4:33the cervical line is irregular
118. 4:36the point of bifurcation of the root is
119. 4:384 mm below the cervical line which is 1
120. 4:41mm more than it is on the buccal surface
121. 4:46the roots appear longer from the lingual
122. 4:49aspect than on the buccal aspect they
123. 4:51measure 1 mm longer lingually then at
124. 4:54the buccal aspect and this appearance is
125. 4:56because of the higher kospel ridges and
126. 4:58higher position of the cervical line in
127. 5:01addition the mesio-distal measurement of
128. 5:03the root trunk is less toward the
129. 5:05lingual surface than it is at the buccal
130. 5:07surface
131. 5:14from the measles aspect the crown is
132. 5:16roughly rhomboidal in shape
133. 5:18two cusps which are the mesiobuccal and
134. 5:21the mesolingual curves with the mesial
135. 5:23root is visible from this aspect
136. 5:26the distal aspect cannot be seen from
137. 5:28this view due to the higher position of
138. 5:31both mesial curves and the broader
139. 5:33bucco-lingual dimension of the crown and
140. 5:35the mesial root at the measles aspect
141. 5:43the buckle outline is convex immediately
142. 5:46above the cervical line at the buccal
143. 5:48cervical ridge
144. 5:50this ridge is prominent on first molars
145. 5:53then on other molars
146. 5:55the lingual outline of the crown is
147. 5:57straight starting at the cervical line
148. 5:59up to the height of contour located at
149. 6:01the middle of the middle third
150. 6:07the cervical line is convex towards the
151. 6:10crown and it is slightly occlusal in the
152. 6:12lingual half then at the buccal half
153. 6:27from the distal aspect the crown is
154. 6:29shorter and smaller than the mesial
155. 6:31aspect and as the buccal and lingual
156. 6:34surfaces converge towards the distal
157. 6:36surface major portion of the crown is
158. 6:38visible
159. 6:43parts of all five curves are visible
160. 6:45from this aspect
161. 6:49the distal curve is located a little
162. 6:51buckle to the central axis of the crown
163. 6:55the cervical line might be straight or
164. 6:57irregular due to the comparatively
165. 6:59smaller bucco-lingual dimension of the
166. 7:01distal root the lingual border of the
167. 7:03mesial root is also visible from this
168. 7:06aspect
169. 7:08from the occlusal aspect the truth is
170. 7:10hexagonal in shape
171. 7:14the mesio-distal dimension of the crown
172. 7:16is greater than the bucco-lingual
173. 7:17dimension with the mesodictal dimension
174. 7:20greater at the buccal half than the
175. 7:22lingual half
176. 7:24the bucco-lingual dimension of the crown
177. 7:26is greater in the mesial half than on
178. 7:28the distal half the opposite is true for
179. 7:31maxillary molars
180. 7:34all five curves are visible these are
181. 7:37the three buccal cusps and two lingual
182. 7:39curves
183. 7:40the three buccal curves are the
184. 7:42mesiobuccal curse which is the largest
185. 7:44of all the distro buckle cusp and the
186. 7:47digital curse which is the smallest of
187. 7:49all five curses
188. 7:51on the lingual side the two mesolingual
189. 7:54and distrolingual curses are located
190. 7:56which in size are equal to the size of
191. 7:58the distro buckle curse
192. 8:01the occlusal surfaces possess some
193. 8:03ridges fossa pits and grooves
194. 8:06the ridges present are the two mesial
195. 8:08and distal cuspal ridges for each cusp
196. 8:11and the two mesial and distal marginal
197. 8:13ridges
198. 8:18based on the number of curves five
199. 8:20triangular ridges are present
200. 8:23one for each cusp which extends from the
201. 8:25curved tip to the center of the occlusal
202. 8:27surface
203. 8:32one major and two minor fossa are
204. 8:34present the major fossa is the circular
205. 8:37fossa located at the center of the truth
206. 8:40the two minor fosse are the mesial
207. 8:42triangular fossa located immediately
208. 8:45distal to the mesial marginal ridge and
209. 8:47the distal triangular fossa located
210. 8:50immediately measles to the distal
211. 8:52marginal ridge or let's say they are
212. 8:54located at either sides of the central
213. 8:56fossa
214. 9:00the grooves are the central
215. 9:02developmental groove which runs in a
216. 9:04mesio-distal direction starting from the
217. 9:06measle pit on one side and ending at the
218. 9:09distal pit on the other
219. 9:17the mesio-buccal developmental groove
220. 9:19which runs between the buccal and the
221. 9:21distrobuckle curve the distrobuccal
222. 9:24developmental groove which runs in
223. 9:26between the distrobuccal and the distal
224. 9:28curve and the lingual developmental
225. 9:30groove which runs in between the two
226. 9:32lingual curves
227. 9:34some supplementary grooves are also
228. 9:36present
229. 9:37all these grooves converge in the center
230. 9:39of the central fossa at the central pit
231. 9:44i hope this video helps if you think
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