Development of Dentition and Occlusion _Dr. Nabil Al-Zubair

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Development of Dentition and Occlusion _Dr. Nabil Al-Zubair

  1. 1. Development ofdentition & occlusion• Dr. Nabil Al-Zubair
  2. 2. Dental development Six-week-old embryo• Dental development usually begins in the 5th or 6th week of prenatal life. A-mandibular process B-maxillary process C-lateral nasal processes D-medial nasal process E-naso-optic furrows
  3. 3. • The embryonic Oral Cavity is lined by Str. squ epithelium known as the Oral Ectoderm
  4. 4. Around the 6th week of intra-uterine life (1) The infero-lateral border of the maxillary arch & (2) The supero-lateral of the mandibular arch show Localized proliferation ORAL ECTODERMResulting in the Horse-shoe shapedformation band of tissue DENTAL LAMINA
  5. 5. (1) The infero-lateral border of the maxillary arch & (2) The supero-lateral of the mandibular arch show Localized proliferation ORAL ECTODERMResulting in the Horse-shoe shaped band of tissueformation DENTAL LAMINAAround the 6th week of intra-uterine life
  6. 6. DENTAL LAMINA: Two meanings first refers From this Thickening in the ectoderm A secondary dental lamina Grows down into the mesenchyme At intervals Dental Organs Along this deep lamina(tooth buds) form
  7. 7. DENTAL LAMINA: Two meanings As the dental organs are established the original surface lamina reverts to oral lining ectoderm (differentiating into gingival epithelium) the secondary lamina starts to disintegrate leaving The first dental organ Successional lamina for the second tooth bud
  8. 8. ‫المالءة‬ DENTAL LAMINAPlays an important role in the development of the dentition LAMINA = Sheet ‫صفيحة رقيقة‬ Tongue Dental lamina Vestibular lamina
  9. 9. • Formation of the deciduous tooth germs occurs on the labial aspect of the dental lamina (DL).• The free tip of DL proliferates into the ectomesenchyme as the successional lamina (SL) providing the anlage ‫ البداءة‬for a permanent tooth. •Dental papilla (DP), dental follicle (DF).
  10. 10. All teeth originate from the dental laminaDECIDUOUS TEETH are formed by DIRECT proliferation of the dental lamina PERMANENT MOLARS develops as a result of its DISTAL proliferation Permanent teeth that replace the deciduous teeth form a lingual extension
  11. 11. All teeth originate from the dental lamina DENTAL LAMINA will grow back to form germs for 3 permanent molars BONE DECIDUOUS TEETH formed by 10 TOOTH GERMDIRECT proliferation of the 20 Successional TOOTH dental lamina GERM on lingual side of 10 PERMANENT MOLARS develops as a result of its DISTAL proliferation SYMPHYSEAL CARTILAGE Permanent teeth that replace the deciduous teeth form a lingual extension
  12. 12. All teeth originate from the dental laminaDECIDUOUS TEETH are formed by DIRECT proliferation of the dental lamina PERMANENT MOLARS develops as a result of its DISTAL proliferation Permanent teeth that replace the deciduous teeth form a lingual extension
  13. 13. Mitotic area TOOTH PRIMORDIUM/GERM BUD The ectoderm in certain areas of the dental lamina proliferates & form knobs-like structures that grow into the underlying mesenchyma Oral Ectoderm knobs-like structuresMesenchyme
  14. 14. Each of this knobs represents a future deciduous tooth & is called ENAMEL ORGAN ENAMEL ORGAN DENTAL LAMINA TOOTH GERM • The enamel organ passes through a number of stages ultimately forming the teeth
  15. 15. • Based on the shape of the enamel organ, the development of teeth BUD can be divided into three stages CAP • They are the bud, cap & bell stage Outer dental epithelium DENTAL LAMINA Stellate reticulum Stratum intermedium BELL TOOTH GERMInner dental epithelium
  16. 16. Stages of Tooth Development • Dental lamina • Bud • Cap • Bell
  17. 17. BUD STAGEOral ectoderm (1) Thickening in the ectodermNext step tothe (2) downgrowthsof dental lamina Formation of a BUD from the dental lamina
  18. 18. BUD STAGEThis is the initial stage of tooth formation where The enamel organ resembles A small bud Enamel organ
  19. 19. BUD STAGE The surrounding mesenchymal cells result inCondensation in TWO areas Proliferate1- Immediately below the enamel organ Dental Papilla 2- Surrounds the tooth bud & the dental papilla Dental Sac
  20. 20. 1- Immediately below the enamel organ Dental Papilla2- Surrounds the tooth bud & the dental papilla Dental Sac
  21. 21. A: ENAMEL ORGAN•The cells of the dental papilla C: DENTAL SAC form the DENTIN & PULP while the dental sac forms CEMENTUM & PERIODONTAL LIGAMENT B: DENTAL PAPILLA
  22. 22. BUD STAGE Usually 10 tooth buds are in each dental arch give rise to Future Primary teeth BONE 10 TOOTH GERM Tooth buds for 20 Successional TOOTH GERM on lingual side of 10 Permanent Teeth form b/w the 17th week of fetal life through the age of 5. SYMPHYSEAL CARTILAGE
  23. 23. DENTAL LAMINA Tooth Bud Continue to proliferate Resulting in A CAP shaped Enamel Organ
  24. 24. Continue to proliferate Tooth Bud Resulting inA CAP shapedEnamel Organ
  25. 25. CAP STAGE• The tooth bud continues to proliferate resulting in a cap shaped Enamel Organ• This is characterized by a shallow invagination on the under surface of the bud
  26. 26. Cap Stage This stage is also known as Proliferation(reproduction or multiplication)in which Cells of the tooth GROWThe tooth bud Takes a hollowed caplike shape
  27. 27. The outer cells of the cap covering the Convexity are cuboidal & are called the “OUTER ENAMEL EPITHELIUM” The cells lining the Concavity of the cap become tall columnar & are referred to as the “INNER ENAMEL EPITHELIUM”
  28. 28. The central area of the enamel organ b/w the outer & inner enamel epithelium, acquire more inter-cellular fluid & forms a cellular network called the Stellate reticulum Cap determines: position, type, & size of tooth
  29. 29. Bell Stage Due to uneven growth ENAMEL ORGAN (CAP) BELL SHAPEalso known as Histodifferentiation (the acquisition of tissue characteristics by cell groups)
  30. 30. Bell Stage: DENTAL ORGAN: Cap, becoming Bell stage The last period of growth is also known as Histodifferentiation(the acquisition of tissue characteristics by cell groups) or bell stage.
  31. 31. Bell stage (5) Dental papilla Odontoblasts Outer dental epithelium Dentin DENTAL LAMINA (3) Stellate reticulum (2) Stratum intermedium Stratum intermedium TOOTH GERM (1)Inner dental epithelium (4) Ameloblasts Enamel
  32. 32. Bell stage (5) Odontoblasts Rich in capillary network dental papilla Outer dental epithelium (3) Stellate DENTAL LAMINA reticulum (2) Stratum intermedium TOOTH GERM(1) Inner dental epithelium Ameloblasts (4) Enamel P. fibres
  33. 33. TOOTH TISSUES: Sources ENAMELDENTAL ORGAN DENTAL LAMINA DENTINE MESENCHYME PULP CEMENTUM DENTAL PAPILLA PDL DENTAL SAC/FOLLICLE ALVEOLAR BONE A BONE
  34. 34. TOOTH TISSUES: Cell Sources DENTAL LAMINA TOOTH DENTAL ORGAN ENAMEL Ameloblasts DENTAL PAPILLA DENTINE Odontoblasts PULP CT cellsDENTAL SAC/FOLLICLE CEMENTUM Cementoblasts PDL Fibroblasts ALVEOLAR BONE A BONE Osteoblasts & „clasts Crest
  35. 35. Root Formation
  36. 36. Root formation• Root development begins:After the dentine & enamel formation reaches the future cemento-enamel junction• The outer & inner enamel epithelium join & form a sheath that helps in molding the shape of the root• This sheath is called the“HERTWIG‟S EPITHELIAL ROOT SHEATH “
  37. 37. Root Formation Cervical loop forms the epithelial root sheath (of Hertwig) Cervical loop Dental papilla
  38. 38. Development of occlusion
  39. 39. Occlusion• Occlusion is the relationship of the mandibular and maxillary teeth when closed or during excursive movements of the mandible; when the teeth of the mandibular arch come into contact with the teeth of the maxillary arch in any functional relationship.
  40. 40. Periods of occlusal development
  41. 41. Occlusal development can be divided into the following developmental periods: 1. Pre – dental period 2. The deciduous dentition period 3. The mixed dentition period 4. The permanent dentition period
  42. 42. Pre – dental period This is the period after birthduring which the neonate does nothave any teeth It usually lasts for 6 months afterbirth
  43. 43. GUM PADS• The alveolar processes at the time of birth are known as gum pads• The gum pads are:(1) pink,(2) firm &(3) covered by a dense layer of fibrous periosteum
  44. 44. GUM PADS• They are HORSE-SHOE shaped & develop in two parts:(1) the labio-buccal portion &(2) the lingual portion• The two portions of the gum pads are separated from each other by a groove called the dental groove
  45. 45. GUM PADS Lateral sulcus• The gum pads are divided into TEN SEGMENTS by certain grooves called TRANSVERSE GROOVES• Each of these segments consist of one developing deciduous tooth sac• The gingival groove separates the gum pads from the palate & floor of the mouth• The transverse groove b/w canine & first deciduous molar segment is Transverse grooves called the lateral sulcus
  46. 46. Lateral sulcus• The lateral sulcus of the mandibular arch is normally more DISTAL to that of the maxillary arch• The upper gum pad is both(1) wider as well as(2) longer thanthe mandibular gum pad Lateral sulcus
  47. 47. • Thus when the upper & lower gum Complete overjet pads are approximated, there is a complete overjet all around(1) Contact occurs b/w the upper & lower gum pads in the first molar region &(2) A space exist b/w them in the anterior region• This infantile open bite is Open bite considered normal & it helps in suckling
  48. 48. The status of dentition• The neonate is without teeth for about 6 months of life(1) At birth:The gum pads are not sufficiently wide to accommodate the developing incisors which are crowded in their crypts(2) During the first year of life:The gum pads grow rapidly permitting the incisors to erupt in good alignment
  49. 49. The status of dentition Very rarely teeth are found to have erupted at the birth time• Such teeth that are present at the time of birth are called NATAL TEETH• Sometimes teeth erupt at an early age• Teeth that are erupt during the first month of age are called Neonatal teeth• The natal & neonatal teeth are mostly (1) LOCATED in the mandibular incisor region & (2) Show a familial tendency
  50. 50. The deciduous dentition period
  51. 51. Cause AetiologyPre – dental period (lasts for 6 (complete overjet)The upper This is the period after months after gum pad is both (1) wider as well as birth during which the birth) (2) longer than the mandibular gum neonate does not have any teeth  gum pads Ant. open bite (divided into TEN Contact occurs b/w the upper SEGMENTS) & lower gum pads in the first molar region  A space exist b/w them in the anterior regionDeciduous dentition - Rarely endogenous tongue thrust
  52. 52. Cause AetiologyDeciduous dentition (lasts from 6 months 1. Spacing usually exists b/w the deciduous teethThe eruption begin at after birth to 6 yrs) 2. A normal feature of deciduousabout 6 months&  sequence of eruption dentition is a Flush Terminalcompleted by 2 ½ - 3 ½ A–B–D–C–E Planeyears of age 3. A deep bite may occur in the Initial Stages of development
  53. 53. The deciduous dentition period• The initiation of primary tooth buds occurs during the first 6 weeks of intra-uterine life• The primary teeth begin to erupt at the age of about 6 months• The eruption of all primary teeth is completed by 2 ½ - 3 ½ years of age when the second deciduous molars come into occlusion
  54. 54. DECIDUOUS DENTITION 5 months in utero 2 yrs (± 6 mos.) 7 months in utero 3 yrsPRENATAL (± 6 mos.) Birth 6 mos. 4 years (± 2 mos.) (± 9 mos.) 9 mos. (± 2 mos.) 5 yrs (± 9 mos.) 1 year (± 3 mos.) 6 years (± 9 mos.) 18 months (± 3 mos.) EARLY CHILDHOOD INFANCY (Pre-school age)
  55. 55. Eruption age & sequence of deciduous dentition• The mandibular central incisors are the first teeth to erupt into the oral cavity• They erupt around 6-7 months of age
  56. 56. The sequence of eruption of the deciduous dentition is: A–B–D–C–E Central Incisors (6 – 8 mo) Usual Order of Appearance: Lateral Incisors (6 – 10 mo) Canines (16 – 20 mo) First Molars (10 – 15 mo)Second Molars (2 ½ - 3 ½ years ) Mandibular Teeth Usually Precede Maxillary in order of Appearance
  57. 57. The primary dentition is usually established by 3 years of age on eruption ofthe second deciduous molarsB/w 3 – 6 years of age, the dental arch is relatively stable & very few changesoccurs Central Incisors (6 – 8 mo) Lateral Incisors (6 – 10 mo) Canines (16 – 20 mo) First Molars (10 – 15 mo) Second Molars (2 ½ - 3 ½ years )
  58. 58. DECIDUOUS DENTITION 1. Spacing usually exists b/w the deciduous teeth2. A normal feature of deciduous dentition is a Flush Terminal Plane 3. A deep bite may occur in the Initial Stages of development
  59. 59. 1 Spacing in deciduous dentitionSpacing usually exists b/w thedeciduous teeth• These spaces are calledPhysiological spaces orDevelopmental spaces
  60. 60. Spacing in deciduous dentition Spacing• The presence of spaces in the PRIMARY DENTITION is important for the normal development of the PERMANENT DENTITION
  61. 61. Spacing in deciduous dentition No Spacing• Absence of spaces in the primary dentition is an indication that crowding of teeth may occur when the LARGER permanent teeth erupt
  62. 62. 2 Flush terminal plane• The mesio – distal relation b/w the DISTAL SURFACE of the lower & upper Second Deciduous Molars is called the terminal plane• A normal feature of deciduous dentition is a Flush Terminal Plane where the distal surfaces of the upper & lower second deciduous molars are in the same vertical plane
  63. 63. 3 Deep bite• A deep bite may occur in the Initial Stages of development• The deep bite is accentuated by the fact that the deciduous incisors are more upright than their successors• The lower incisal edges often contact the cingulum area of the maxillary incisors
  64. 64. Deep biteThis deep bite is later Reduceddue to the following factors:a. Eruption of deciduous molarsb. Attrition of incisorsc. Forward movement of the mandible due to growth
  65. 65. The mixed dentition period
  66. 66. A panoramic x-ray of a 7 year-old child. One cannotice the complex mix of the permanent andthe primary teeth at this stage.
  67. 67. The mixed dentition period• The mixed dentition period begins at approximately 6 years of age with the eruption of the first permanent molars• During the mixed dentition period, the deciduous teeth along with some permanent teeth are present in the oral cavity
  68. 68. The mixed dentition periodThe mixed dentition period can be classified into three phases: 1. First transitional period 2. Inter-transitional period 3. Second transitional period
  69. 69. First transitional period• The first transitional period is characterized by :(1) the emergence of the first permanent molars &(2) the exchange of the deciduous incisors with the permanent incisors
  70. 70. Emergence of the first permanent molars:• The mandibular first molar is the first permanent tooth to erupt at around 6 years of age
  71. 71. Emergence of the first permanent molars:• The (1) location & (2) relationship of the first permanent molars depends much upon the DISTAL SURFACE relationship b/w the lower & upper second deciduous molars
  72. 72. Emergence of the first permanent molars:• The first permanent molars are Guided into the dental arch by distal surface of the second deciduous molars• The mesio-distal relation b/w the Distal Surfaces of the upper & lower second deciduous molars can be of three types
  73. 73. THE THREE TYPES OF TERMINAL PLANESFLUSH PLANE MESIAL STEP DISTAL STEP TYPE TYPE TYPE
  74. 74. A. Flush terminal plane:• The distal surface of the upper & • This is a normal feature of the lower second deciduous molars deciduous dentition are in VERTICAL PLANE • Thus the erupting first• This type of relationship is called permanent molars may also be flush or vertical terminal plane in a flush or end on Class I molar relationship
  75. 75. Flush Class I molar• For such transitionthe lower molar has to move forward by about 3 – 5 mm relative to the upper molar
  76. 76. Flush Class I molar• This occurs by(1) utilization of the physiological spaces & leeway space in the lower arch &(2) by differential forward growth of the mandible
  77. 77. Flush• The shift in lower molar can occur in two ways Class I relation• They are designated as the Late shift Early shift Shift: Refers to mandibular permanent molar moving mesially
  78. 78. Early shift:• Occurs during the early mixed Primate space dentition period• The ERUPTIVE FORCE of the first permanent molar is sufficient to push the deciduous first & second molars forward in the arch to close the PRIMATE SPACE• Since this occur early in the mixed dentition period it is called early shift
  79. 79. • Many children lack the primate space lack the primate Late shift space & thusthe erupting permanent molars unable to move forward to establish Class I relationship• In this cases, when the deciduous second molar exfoliate the permanent first molars DRIFT MESIALLY utilizing Leeway spacethe leeway space This occurs in the late mixed dentition period & is thus called late shift
  80. 80. Late Mesial Shift (cont.) Molar moves intoFTP this space... Class I
  81. 81. Late Mesial Shift (cont.)
  82. 82. B. Mesial step terminal plane• In this type of relationship the Distal Surface of the lower second deciduous molar is more Mesial than that of the upper• Thus the permanent molars erupt directly into Angle’s Class I occlusion
  83. 83. B. Mesial step terminal plane• This type of mesial step terminal plane most commonly occurs due to EARLY FORWARD GROWTH OF THE MANDIBLE• If the differential growth of the mandible in a forward direction persist, it can lead to an Angle‟s Class III molar relation• If the forward mandibular growth is minimal, it can establish a Class I molar relationship
  84. 84. B. Mesial step terminal plane• This type of mesial step terminal plane most commonly occurs due to EARLY FORWARD GROWTH OF THE MANDIBLE• If the differential growth of the mandible in a forward direction persist, it can lead to an Angle‟s Class III molar relation
  85. 85. C. Distal step terminal plane • This is characterized by the Distal Surface of the lower second deciduous molar being more DISTAL to that of the upper • Thus the erupting permanent molars maybe in Angle‟s Class II occlusion
  86. 86. C. Distal step terminal plane • This is characterized by the Distal Surface of the lower second deciduous molar being more DISTAL to that of the upper • Thus the erupting permanent molars maybe in Angle‟s Class II occlusion
  87. 87. Primary PermanentDistal Step Class IIFlush Terminal End-End Plane Class I Mesial Step Minimal Growth Differential Class III Forward Growth of Mandible Shift of Teeth
  88. 88. First transitional period• The first transitional period is characterized by :(1) the emergence of the first permanent molars &(2) the exchange of the deciduous incisors with the permanent incisors
  89. 89. The exchange of incisors:• During the first transitional period:The deciduous incisors are replaced by the permanent incisors• The mandibular central incisors are usually the first to erupt• The permanent incisors are considerably larger than the deciduous teeth they replace
  90. 90. The exchange of incisors: • This difference b/w the amount of space needed for the accommodation of the incisors & amount of space available for this is called “INCISAL LIABILITY” 7 mm in the maxillary arch 5 mm in the mandibular arch
  91. 91. Overcoming Incisal Liability The incisal liability is overcome by the following factors: A. Utilization of interdental spaces seen in primary dentition B. Increase in the inter – canine width C. Change in incisor inclination
  92. 92. Overcoming Incisal Liability A. Utilization of interdental spaces seen in primary dentition:• The physiologic or the developmental spaces that exists in the primary dentition are utilized to partly account for the incisal liability
  93. 93. Overcoming Incisal Liability A. Utilization of interdental spaces seen in primary dentition:• The Permanent Incisors are much more easily accommodated innormal alignment in cases exhibiting Adequate Inter-dental Spaces than in an arch that has No space
  94. 94. Primary dentition, baby teeth, withnormal spaces between the teeth
  95. 95. Overcoming Incisal Liability B. Increase in the inter – canine width: – WIDTH GROWTH creates more room for the permanent incisors(1) Mandibular intercanine growthoccurs mostly during permanent incisor eruption(2) Maxillary intercanine growth occurs during incisor eruption, and continues
  96. 96. Overcoming Incisal Liability C. Change in incisor inclination:• One of the differences b/w deciduous & permanent incisors is their inclination• The primary incisors are more uprightthan the permanent incisors
  97. 97. Overcoming Incisal Liability C. Change in incisor inclination:s • Since the Permanent Incisors erupt more labially inclined they tend to increase the Dental Arch Perimeter• This is another factor that helps in accommodating the larger Permanent Incisors
  98. 98. The mixed dentition periodThe mixed dentition period can be classified into three phases: 1. First transitional period 2. Inter-transitional period 3. Second transitional period
  99. 99. Inter – transitional period• In this period the maxillary & mandibular arches consist of Sets of deciduous & permanent teeth 6edc21 12cde6 6edc21 12cde6• B/w the permanent incisors & the first permanent molars are the deciduous molars & canines• This phase during the mixed dentition period is relatively stable & no change occurs
  100. 100. The mixed dentition periodThe mixed dentition period can be classified into three phases: 1. First transitional period 2. Inter-transitional period 3. Second transitional period
  101. 101. Cause AetiologyThe mixed  deciduous The first transitional period is characterized by :dentition period teeth along with (1) the emergence of the first permanent molars some permanent Flush transition to Class I molarThe eruption begin teeth are present in (2) the exchange of the deciduous incisors withapproximately at 6years of age with the the oral cavity the permanent incisors “INCISAL LIABILITY”eruption of the first Classified into Inter – transitional periodpermanent molars three phases: ( First , Relatively stable & no change occurs Inter-transitional , The second transitional period Second) transitional period Replacement of the deciduous molars & canines by the premolars & permanent cuspids respectively
  102. 102. The second transitional period• The second transitional period is • The surplus is called leeway characterized by space of Nancethe replacement of the deciduous molars & canines by the premolars & permanent cuspids respectively• The combined mesio-distal width of the permanent canines & premolars is usually less than that of the deciduous canines & molars
  103. 103. The leeway spaces Maxillary arch 1.8mm (0.9 mm on each side of the arch) Mandibular arch• The amount of leeway space is greater in the mandibular arch 3.4mm (1.7 mm on each side of the arch) than in the maxillary arch
  104. 104. The leeway spacesMaxillaryc-d-e minus 3-4-5 is 0.9 mm per sideMandibularc-d-e minus 3-4-5 is 1.7 mm per side
  105. 105. The ugly duckling stage:• Sometimes a Transient or Self Correcting malocclusion is seen inthe MAXILLARY INCISOR REGION b/w 8 – 9 years of ageThis is a particular situation seen during the Eruption of the permanent canines
  106. 106. The ugly duckling stage: 7 years old 9 years old 14 years old• As the developing permanent canines erupt, they displace the roots of the lateral incisors mesially• This result in transmitting of the force on to the roots of the central incisors which also get displaced mesially
  107. 107. The ugly duckling stage: 7 years old 9 years old 14 years old• A resultant distal divergence of the crowns of the two central incisors causes a midline spacing• This situation has been described by Broadbent as the ugly duckling stage as children tend to look ugly during this phase of development
  108. 108. The ugly duckling stage:7 years old 9 years old 14 years old • Parents are often apprehensive during this stage & consult the dentist • This condition usually corrects by itself when the canines erupt & the pressure is transferred from the roots to the coronal area of the incisors
  109. 109. The permanent dentition period
  110. 110. The permanent dentition period• The permanent dentition forms within the jaws soon after birth, except the cusps of the first permanent molars which form before birth• The permanent incisors develop lingual or palatal to the deciduous incisors & move labially as they erupt
  111. 111. The permanent dentition period• The premolars develop below the diverging roots of the deciduous molars• The eruption sequence of the permanent dentition may exhibit variation
  112. 112. The permanent dentition period • The frequently seen sequences in the maxillary arch are: – 6 – 1 – 2 – 4 – 3 – 5 – 7 or – 6–1–2–3–4–5–7 • In case of the mandibular arch the sequence is – 6 – 1 – 2 – 3 – 4 – 5 – 7 or – 6–1–2–4–3–5–7
  113. 113. Time of Eruption (Years) Tooth Maxilla Mandible 1 7-8 6-7 2 8-9 7-8 3 11-12 9-10 4 10-11 10-12 5 10-12 11-12 6 6-7 6-7 7 12-13 11-13 8 17-21 17-21
  114. 114. Chronology of Tooth Development Permanent Dentition Calcification Crown Eruption Root completed begins completedTooth Max. Mand. Max. Mand. Max. Mand. Max. Mand.Central 3 mo. 3 mo. 4 ½ yr. 3 ½ yr. 7 ¼ yr. 6 ¼ yr. 10 ½ yr. 9 ½ yr.Lateral 11 mo. 3 mo. 5 ½ yr. 4 yr. 8 ¼ yr. 7 ½ yr. 11 yr. 10 yr.Canine 4 mo. 4 mo. 6 yr. 5 ¾ yr. 11 ½ yr. 10 ½ yr. 13 ½ yr. 12 ¾ yr.1st Pre 20 mo. 22 mo. 7 yr. 6 ¾ yr. 10 ¼ yr. 10 ½ yr. 13 ½ yr. 13 ½ yr.Molar2nd Pre 27 mo. 28 mo. 7 ¾ yr. 7 ½ yr. 11 yr. 11 ¼ yr. 14 ½ yr. 15 yr.Molar1st Molar 32 wk. 32 wk. 4 ¼ yr. 3 ¾ yr. 6 ¼ yr. 6 yr. 10 ½ yr. 10 ¾ yr. in utero in utero2nd Molar 27 mo. 27 mo. 7 ¾ yr. 7 ½ yr. 12 ½ yr. 12 yr. 15 ¾ yr. 16 yr.3rd Molar 8 yr. 9 yr. 14 yr. 14 yr. 20 yr. 20 yr. 22 yr. 22 yr.
  115. 115. ?
  116. 116. SEQUENCES of DENTAL ERUPTIONFavorable sequence Unfavorable sequence
  117. 117. SEQUENCES of DENTAL ERUPTIONFavorable sequence -345 -435 - (3 4) 5 - 3 (4 5)
  118. 118. SEQUENCES of DENTAL ERUPTION Unfavorable sequence - 543 -534 - 5 (3 4) -453
  119. 119. SEQUENCES of DENTAL ERUPTION Unfavorable sequenceSECOND MOLARS erupting before Second premolars and/or CANINES
  120. 120. 4. Favorable sequences of eruption.5. Tooth size and jaw in harmony.
  121. 121. n
  122. 122. Thank you for listening! Dr. Nabil Al-Zubair

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