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Morphology of deciduous dentition


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Morphology of deciduous dentition

  2. 2. Functions of primary teeth  needed for efficient chewing of food  provide support for lips and cheeks maintaining a normal facial appearance and smile  formulation of clear speech  critical for maintaining space for permanent teeth to erupt
  3. 3. Important times for tooth eruption 1. NO TEETH (EDENTULOUS) • From birth to 6 months old (approximately): There are no teeth visible within the mouth. 2. PRIMARY DENTITION ONLY • 6 months to 2 years old (approximately): All primary teeth are erupting into the child’s mouth over this period. • 2 to 6 years old (approximately): All 20 primary teeth are present; no permanent teeth are yet visible in the mouth.
  4. 4. Important times for eruption  3. MIXED DENTITION • 6 years old (approximately): Permanent teeth start to appear, beginning with the first molars (also called 6-year molars) just distal to the primary second molars. followed closely by the loss of the primary mandibular central incisors, which are quickly replaced by the permanent mandibular central incisors.  • 6 to 9 years old: All eight permanent incisors replace primary incisors that are exfoliated (shed).
  5. 5. Important times for eruption  9 to 12 years old: All four permanent canines and eight premolars replace primary canines and molars. • 12 years old: Second molars (also called 12-year molars) emerge distal to the permanent first molars.
  6. 6. Important times for eruption 4. ADULT DENTITION ONLY • After 12 years (second) Molars erupt, 28 permanent teeth are present, and all primary teeth have been exfoliated and replaced. • 17 to 21 years old: Third molars (if present) emerge.
  7. 7. Deciduous versus permanent dentition Smaller in size Shorter crown height relative to total crown root length Greater crown width mesiodistally relative to inciso(occluso) gingival height  Relatively longer roots than their crowns compared to permanent teeth
  8. 8. Deciduous versus permanent dentition CERVICAL RIDGES on labial and lingual surface of anterior teeth  Buccal cervical ridges on deciduous molars  Constricted cervix(squeezed in)  Occlusal aspect: constricted occlusal table
  9. 9. Deciduous versus permanent dentition  Longer and thinner roots when compared to permanent teeth  Flaring or spreading in deciduous molar roots.
  10. 10. Pulp chamber deciduous v/s permanent teeth  Larger pulp chamber compared to permanent teeth
  11. 11. Deciduous Dentition  The layers of enamel and dentin of primary teeth are thinner than on secondary teeth, so the pulp cavities are proportionally larger and therefore closer to the surface  Primary teeth are less mineralized so become very worn  Primate spaces: Interproximal spaces between primary teeth i.e b/w max lateral incisor and canine and b/w mandibular canine and first molar--- proper alignment of permanent
  12. 12. Dental formula
  13. 13. Deciduous teeth
  14. 14. 1. Prominent cervical ridges on facial surfaces run mesiodistally 2. The prominent lingual cingula seem to bulge and occupy about one third of the cervicoincisal length 3. No depressions, mamelons, or perikymata on the labial surface of the crowns of the primary incisors TRAITS OF ALL PRIMARY ANTERIOR TOOTH CROWN
  15. 15. ROOT TRAITS OF ANTERIOR TEETH  The roots of primary anterior teeth are long in proportion to crown length and are relatively narrow mesiodistally  The roots of primary anterior teeth bend labially in their apical one third to one half by as much as 10 degree.
  16. 16. Deciduous incisors  Eruption Mandibular before maxillary incisors Central before lateral incisors  No mamelons, labial grooves or lobes
  17. 17. Maxillary Central incisor  UNS------------------E, F  FDI--------------------- 51, 61  PALMER-------------- A A  Eruption time------- 7.5months(FULLER)  Order----------------- 1  Shedding----------- 6-7 years
  18. 18. Maxillary Central incisor  Increased mesiodistal width of crown (unique trait)  Rounded mesioincisal and distoincisal angle than permanent successor.  No mamelons on incisal surface+ flat incisal surface  No labial grooves, depressions or lobes  Pronounced bulge on labial surface.
  19. 19. Maxillary Central incisor  Prominent cingulum.  Prominent marginal ridges  Deeper lingual fossa.  No lingual pit
  20. 20. Maxillary Central incisor  MESIAL ASPECT: wider labiolingually  Cervical line exhibits less curvature incisally.  DISTAL ASPECT:  Cervical line curvature less on distal surface as compared to mesial surface.
  21. 21. Maxillary Central incisor Incisal Aspect  Straight incisal edge  Divides the crown into equal labial and lingual portions.  Greater mesiodistal width.
  22. 22. Maxillary Central incisor  Single root  Tapers evenly to the apex  Root longer relative to crown length.
  23. 23. Maxillary Lateral Incisor  UNS--------------------D ,G  FDI--------------------- 52, 62  PALMER--------- B B  Eruption time------- 9 months(FULLER)  Order----------------- 2  Shedding------------ 7 -8 yrs
  24. 24. Maxillary Lateral incisor  Much smaller than central (trapezoidal labially, triangular proximal aspect)  Crown is wider incisocervically than mesiodistally.  Distoincisal angle more rounded than mesioincisal angle  Marginal ridges on lingual surface more prominent  Lingual fossa is deep
  25. 25. Maxillary lateral incisor Incisal aspect  Much narrower Mesiodistal dimension  more rhomboidal & more convex.
  26. 26. Maxillary Lateral Incisor ROOT  Lateral incisor root relatively longer  Apex not so rounded.
  27. 27. Lok virsa museum islamabad DR UMAR KHITAB
  28. 28. Mandibular teeth
  29. 29. Mandibular central incisor  UNS-------------------- P, O  FDI--------------------- 81, 71  Eruption time------- 6 months(FULLER)  Order----------------- 1  Shedding------------ 6-7 yrs
  30. 30. Mandibular central incisor  Chisel shape incisor morphology  Sharp mesioincisal and distoincisal angles to the cervial line(90 DEGREES)  Incisal margin straight,no mamelons.  Smooth labial surface lacking developmental depressions.  Flatter than labial surface of permanent incisors.  Labially symmetrical crown  Bulge on labial surface at CEJ.
  31. 31. Mandibular central incisor  Well developed lingual cingulum  Less defined marginal ridges than those of maxillary deciduous central incisor.  Shallow lingual fossa
  32. 32. Mandibular central incisor Proximal aspect;  Triangular in shape/ wedge shaped when seen from mesial or distal aspect.  Incisal edge located over root centre.  Cervical line contour evenly curved towards incisal.  Greater labiolingual width than that of permanent incisors.  Distal aspect shows less depth of curvature towards incisal.
  33. 33. Mandibular central incisor  Straight incisal edge  Divides the labial and lingual portions of the crown into nearly equal halves.  In deciduous maxillary central incisor the crown is wider MD.  M & D portions of crown symmetrical
  34. 34. Mandibular central incisor  Single ,long ,slender  Convex labial and lingual surfaces.  Flattened mesial and distal surfaces.
  35. 35. Mandibular Lateral Incisor  UNS--------------------Q , N  FDI--------------------- 82, 72  Eruption time------- 7 MONTHS  Order----------------- 2  Shedding------------ 7-8 years
  36. 36. Mandibular lateral incisor  Similar in form to deciduous central incisor.  Distoincisal angle is rounded, mesioincisal angle is sharp.  Labial/lingual aspect: Incisal outline slopes slightly towards the distal
  37. 37. Mandibular Lateral Incisor  Lingual Aspect  Cingulum and marginal ridges little larger.  Lingual fossa little deeper.
  38. 38. Mandibular Lateral Incisor  Incisal aspect: crown not symmetrical.  Cingulum bulges towards distal.
  39. 39. Mandibular lateral incisor  Single root  Longer root than central incisor  Distal curvature apically.  Distal longitudinal groove.
  40. 40. Maxillary deciduous canine
  41. 41. Maxillary canine  UNS--------------------C (rt) , H(lt)  FDI--------------------- 53, 63  Eruption time------- 19 MONTHS  Order----------------- 4  Shedding------------ 10-12 years
  42. 42. Maxillary canine  MD width > crown height(Incisocervical measurement)  Labial or lingual views: diamond in shape  Rounder mesial and distal outlines.  M & D outlines overhang the cervical line.  M& D contact areas located at the same level incisocervically.  Mesial cusp slope longer than distal cusp slope.  No labial ridge or depressions  No imbrication lines.
  43. 43. Maxillary canine  Well developed cingulum.  Prominent marginal ridges.  ML and DL fossae are present  Tubercle often present on the cingulum extending from the cusp tip to cingulum.
  44. 44. Maxillary canine  Mesial aspect Triangular in shape  Labial margin convex incisocervically  Lingual margin concave in incisal half and convex in cervical half  Labiolingually tooth is thicker  Cervical line depth less
  45. 45. Maxillary canine Distal Aspect  Similar to mesial except that cervical line shows less curvature. Incisal aspect  Rhomboidal outline  Exhibits more rounding incisal than the permanent canine.  Cusp tip offset to distal.  Mesial cusp ridge therefore longer.
  46. 46. Maxillary canine  ROOT  Single root  Root approx twice the length of crown  Wider labiolingually than mesiodistally.
  48. 48. Mandibular canine  UNS-------------------- R ,M  FDI--------------------- 83, 73  Eruption time------- 16 MONTHS  Order----------------- 4  Shedding------------ 9-12 years
  49. 49. Mandibular canine  Smaller and slimmer overall than the maxillary deciduous canine.  MD width of mandibular primary canine< MD width of maxillary pri canine.  Incisocervical ht> MD Width.
  50. 50. Mandibular canine  Distoincisal slope longer than mesioincisal slope(reverse of max.dec canine)
  51. 51. Mandibular canine  LL diameter < that of deciduous max. canine( much narrower tooth labiolingually)  Less pronounced cingulum, MR & cervical ridges.  Shallower fossae than max canine.
  52. 52. Mandibular canine  Single but shorter root.
  53. 53. TRAITS OF ALL PRIMARY POSTERIOR TOOTH CROWNS  The prominent mesial cervical ridge or bulge on the buccal surface  narrow occlusal table:Due to the taper of the crown from the cervical bulges toward the occlusal surface  molar crowns are wide mesiodistally relative to their height cervico-occlusally
  54. 54. Traits tooth crowns molar  The primary molar occlusal anatomy is shallow;  the cusps are short (not pointed sharp, almost flat), occlusal ridges not pronounced, and fossae and sulci are correspondingly not as deep as on secondary molars.
  55. 55. Traits tooth crowns molar  There are few grooves or depressions in the crowns. 6. In the primary dentition, primary second molars are decidedly larger than primary first molars. This is different in the permanent dentition where first molars are larger than seconds
  56. 56. ROOT TRAITS OF PRIMARY POSTERIOR TEETH  1. The root furcations are near the crown, with little or no root trunk 2.thin and slender roots  This root divergence makes room for the developing succedaneous premolars.  3. The roots of primary molars are similar to those of permanent molars in relative size (before resorption)and number.  Primary maxillary molars have three roots: the palatal (longest), mesiobuccal, and distobuccal (shortest). Primary mandibular molars  have two roots: the mesial (largest) and distal.
  57. 57. Maxillary deciduous molars
  58. 58. Maxillary 1st molar  UNS----------------- B(Right) , I (LEFT)  FDI--------------------- 54, 64  Eruption time------- 14 MONTHS  Order----------------- 3  Shedding------------ 9-11 years
  59. 59. Maxillary 1st molar  Most atypical of all primary or permanent molars  Crown doesnot resemble any other primary or permanent molar crown.  Exhibit some similarities to the crowns of permanent premolars
  60. 60. Maxillary 1st molar BUCCAL ASPECT  MD diameter greater than crown height  Mesial and distal outlines are convex ,constricted towards cervix.  Comparatively straight occlusal outlinetwo buccal cusps not sharp or prominent.
  61. 61. Maxillary 1st molar Essential difference from permanent tooth  Depth of curvature is much greater towards the mesial than distal.  Buccal surface smooth and lacks grooves or depressions.  MOLAR TUBERCLE OF ZUCKERKANDL; pronounced bulge on mesial surface of buccal surface.  Flat surface occlusally
  62. 62. Maxillary 1st molar LINGUAL ASPECT  Lingual surface shorter mesiodistally than buccal surface.  ML cusp quite bulky and dominates the occlusal outline  DL cusp is so diminitive that DB CUSP is also partially visible from this aspect.
  63. 63. Maxillary 1st molar LINGUAL ASPECT  Cervical line is evenly and slightly curved towards cervix.  Convex & smooth surface ,lacking grooves or depressions.
  64. 64. Maxillary 1st molar  MESIAL ASPECT  Disparity b/w the buccolingual widths at its cervical and occlusal margins much more than in max.first permanent molars.  Wider dimension cervically due to prominent cervical ridge on buccal and greater taper of buccal and lingual outlines towards occlusal.
  65. 65. Maxillary 1st molar Mesial Aspect  Buccal outline dominated by cervical ridge and crest of curvature is in cervical third.Remainder of buccal outline straight.  Lingual outline convex.More cervically located crest of curvature than in permanent molars  Occlusal outline MB+ ML cusps and mesial marginal ridge make up the occlusal outline.  ML cusp more generous in height than MB cusp.
  66. 66. Maxillary 1st molar MESIAL ASPECT  Cervical line slightly curved towards occlusal.
  67. 67. Maxillary 1st molar Distal Aspect  Considerably smaller than the mesial surface.  Tapering of buccal surface towards the distal therefore much of the buccal surface visible from distal aspect.  DB cusp more prominent than minute DL cusp.  Distal marginal ridge less pronounced than mesial marginal ridge.  Cervical line is straight to slightly curved occlusally.
  68. 68. Maxillary 1st molar OCCLUSAL ASPECT  UNUSUAL FIVE SIDED FIGURE  Cusps: 4 cusps 1) MB cusp 2) DB cusp 3) ML cusp 4) DL cusp
  69. 69. Maxillary 1st molar Mesiolingual cusp  Largest cusp and longest. Mesiobuccal cusp  MB cusp greater than distobuccal. Distobuccal cusp Distolingual cusp  Smallest cusp.
  70. 70. Maxillary 1st molar Transverse ridge: prominent T-ridge  Formed by lingual cusp ridge of MB cusp and buccal cusp ridge of ML cusp. Oblique Ridge Extends from ML cusp to DB cusp.
  71. 71. Maxillary 1st molar Fossae: 3 fossae 1) CENTRAL FOSSA 2)MESIAL TRIANGULAR FOSSA 3) DISTAL TRIANGULAR FOSSA
  72. 72. Maxillary 1st molar ROOTS  no root trunk.  Root trunk: defined as that portion of root situated b/w cervical line and the point of furcation.  Three roots: 1) MB root 2) DB ROOT 3) Palatal  Slender and flared roots  Largest +longest palatal root.
  73. 73. Maxillary 2nd molar  UNS-------------------- A,J  FDI--------------------- 55, 65  Eruption time------- 24 MONTHS  Order----------------- 5  Shedding------------ 10-12 years
  74. 74. Maxillary 2nd molar  Primary maxillary second molar larger than primary maxillary first molar  Closely resembles the permanent maxillary first molar in form but is smaller in all dimensions.  Usually has a Cusp of Carabelli ,as its permanent counterpart.
  75. 75. Mandibular 1st molar  UNS-------------------- L &S  FDI--------------------- 84, 74  Eruption time------- 12 MONTHS  Order----------------- 3  Shedding------------ 9-11 years
  76. 76. Mandibular 1st molar  crown unlike any tooth of either dentition.(unique crown shape)  Prominent buccal cervical ridge on mesial half of buccal surface.  The HOC on the buccal is at cervical one third  The HOC on the lingual is in the middle one third.
  77. 77. Mandibular first molar  Crown wider mesiodistally than buccolingually
  78. 78. Mandibular primary first molar  Buccal aspect: mesial outline straight occlusogingivally  Distal outline more convex & overhangs the cervical line  Two buccal cusps in occlusal outline MB AND DB CUSP.MB CUSP LARGER.
  83. 83. MESIAL ASPECT  CERVICAL RIDGE representing crest of curvature in cervical third of buccal outline  BOTH MB &ML cusps visible  CONTACT AREA: at the junction of occlusal & middle third  CERVICAL LINE: Located farther cervically on buccal and extends to more occlusal at lingual
  84. 84. Distal aspect  All the four cusps seen  MB Cusp the longest
  85. 85. Mandibular 1st molar  CUSPS: 4 cusps:1)MB 2) ML 3) DB 4) DL  The two mesial cusps are considerably larger than distal cusps.
  86. 86. OCCLUSAL ASPECT  occlusal outline is somewhat oval or rectangular  wider mesiodistally than faciolingually  occlusal table is wider mesiodistally than faciolingually
  87. 87. OCCLUSAL ASPECT  4 CUSPS  MB LARGEST FOLLOWED BY ML,DB,DL (smallest)  The two mesial cusps larger than distal cusps
  88. 88. Mandibular 1st molar  A transverse ridge passes b/w the mesiobuccal and mesiolingual cusps.
  89. 89. OCCLUSAL TABLE  Fossae : 3  Central ,mesial and distal triangular fossae  Two pits: central and mesial pit  Distal pit absent  Central pit :deepest pit and is the central grooves distal termination
  90. 90. Occlusal table  GROOVES  Central:connects mesial and central pits  Buccal: originates in central pit extend buccaly to fade out on occlusal surface b/w two buccal cusps  Lingual:separated the two lingual cusps and fade out on occlusal surface
  91. 91. Mandibular 1st molar Roots  2 roots i.e mesial and distal .  Mesial wider than distal root.  FLAT apex of root mesial root  Shorter distal root having rounded apex
  92. 92. HOW TO TELL RIGHT FROM LEFT PRIMARY TEETH  Crown longer on mesial than distal (facial)  Occlusal table has small mesial triangular fossa; large distal fossa  Mesial cervical crown bulge  Distal marginal ridge more cervical than mesial
  93. 93. HOW TO TELL RIGHT FROM LEFT PRIMARY TEETH Mesial root (if intact) longer and wider (faciolingually
  94. 94. Mandibular 2nd molar  UNS-------------------- K&T  FDI--------------------- 85, 75  Eruption time------- 20 MONTHS  Order----------------- 5  Shedding------------ 10-12 years
  95. 95. Mandibular 2nd molar  Larger than the primary mandibular first molar.  closely resembles the permanent mandibular first molar, disregarding size and general differences.  5 cusps similar to permanent mand first molar.
  96. 96. Mandibular 2nd molar  Major differences are: The 3 buccal cusps (MB,DB& distal) are nearly equal in size.  Occlusal table relatively narrower buccolingually and less pentagonal than that of the first permanent molar.  The mesial root is longer and wider than the distal root whereas they are of equal length in permanent first molar.
  97. 97. ANY QUESTIONS???