Mixed dentition /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Mixed dentition /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Department of orthodontics DEVELOPMENT OF MIXED DENTITION  MIXED DENTITION PERIOD CONSISTS OF BOTH DECIDUOUS & PERMANENT TEETH IN THE ORAL CAVITY.  EXTENDS FROM 6- 12 YEARS OF AGE www.indiandentalacademy.com
  3. 3. MIXED DENTITION CONSISTS OF 3 PHASES: 1. FIRST TRANSITIONAL PERIOD 2. INTER-TRANSITIONAL PERIOD 3. SECOND TRANSITIONAL PERIOD www.indiandentalacademy.com
  4. 4. 1. FIRST TRANSITIONAL PERIOD A. EMERGENCE OF FIRST PERMANENT MOLARS B. EXCHANGE OF DECIDUOUS INCISORS WITH PERMANENT INCISORS www.indiandentalacademy.com
  5. 5. A. EMERGENCE OF FIRST PERMANENT MOLARS MANDIBULAR FIRST MOLAR IS THE FIRST PERMANENT TOOTH TO ERUPT AT AROUND 6 YEARS OF AGE ANTEROPOSTERIOR POSITIONING OF THE PERMANENT MOLARS IS INFLUENCED BY TERMINAL PLANE RELATION-SHIP OF DECIDUOUS 2 ND MOLARS WHICH IS OF 3 TYPES. www.indiandentalacademy.com
  6. 6. 1. FLUSH TERMINAL PLANE  THE DISTAL SURFACES OF THE UPPER AND LOWER 2 ND DECIDUOUS MOLARS ARE IN ONE VERTICAL PLANE.  THIS IS A NORMAL FEATURE OF DECIDUOUS DENTITION www.indiandentalacademy.com
  7. 7.  THE ERUPTING 1ST PERMANENT MOLARS MAY ALSO BE IN A FLUSH OR END-ON RELATION  THE SHIFT IN PERMANENT LOWER MOLAR FROM FLUSH TERMINAL PLANE TO CLASS 1 RELATION CAN OCCUR IN 2 WAYS: 1. EARLY SHIFT 2. LATE SHIFT www.indiandentalacademy.com
  8. 8. 1. EARLY SHIFT  ERUPTIVE FORCE OF 1 ST PERM MOLARS IS SUFFICIENT TO PUSH THE DECI 1ST & 2ND MOLARS FORWARD TO CLOSE THE PRIMATE SPACES & ESTABLISH A CLASS I MOLAR RELATIONSHIP  SINCE THIS OCCURS IN THE EARLY MIXED DENTITION PERIOD, IT IS CALLED EARLY SHIFT www.indiandentalacademy.com
  9. 9. 2. LATE SHIFT  When The Deciduous 2 nd Molars Exfoliate The Permanent 1 st Molars Drift Mesially Utilizing The LEEWAY SPACE OF NANCE.  This Occurs In The Late Mixed Dentition Period & Is Called LATE SHIFT www.indiandentalacademy.com
  10. 10. LEEWAY SPACE OF NANCE  THE COMBINED MESIODISTAL WIDTHS OF DECIDUOUS CANINE, 1ST & 2ND MOLARS IS MORE THAN THAT OF THE COMBINED MESIODISTAL WIDTHS OF PERMANENT CANINE, IST & 2ND PREMOLARS.  THE DIFFERENCE BETWEEN THE TWO IS CALLED LEEWAY SPACE  MAXILLA : 0.9mm/ segment= 1.8mm total  MANDIBLE : 1.7mm/ segment= 3.4mm total www.indiandentalacademy.com
  11. 11. 2. MESIAL STEP TERMINAL PLANE  DISTAL SURFACE OF LOWER 2ND DECIDUOUS MOLAR IS MORE MESIAL THAN THAT OF UPPER  PERMANENT MOLARS MAY ERUPT IN CLASS I BUT IF THE DIFFERENTIAL GROWTH OF MANDIBLE IN THE FORWARD DIRECTION PERSISTS, IT CAN LEAD TO ANGLE’S CLASS III MOLAR RELATION www.indiandentalacademy.com
  12. 12. 3. DISTAL STEP TERMINAL PLANE  DISTAL SURFACE OF LOWER 2ND DECIDUOUS MOLAR IS MORE DISTAL THAN THAT OF THE UPPER  ERUPTING PERMANENT MOLARS MAY BE IN CLASS II OR END-ON RELATION IF DIFFERENTIAL GROWTH OF MANDIBLE PERSISTS www.indiandentalacademy.com
  13. 13. B. EXCHANGE OF INCISORS • DECIDUOUS INCISORS ARE REPLACED BY PERMANENT INCISORS • MANDIBULAR CENTRAL INCISORS ARE USUALLY 1ST TO ERUPT INCISOR LIABILITY : The permanent incisors are larger than the deciduous incisors they replace.This difference between the amount of space needed for accommodation of incisors and the amount of space available is called incisor liability. MAXILLARY ARCH: 7mm MANDIBULAR ARCH: 5mm www.indiandentalacademy.com
  14. 14. INCISOR LIABILITY IS OVERCOME BY : a. UTILIZATION OF PHYSIOLOGICAL SPACES IN PRIMARY DENTITION b. INCREASE IN INTER-CANINE WIDTH: During the transition from primary incisors to permanent incisor there is an increase in inter-canine width of both arches. c. CHANGE IN INCISOR INCLINATION : Permanent incisors erupt more labially inclined as compared to primary incisors which are usually upright. This causes increase in dental arch perimeter www.indiandentalacademy.com
  15. 15. INTER-INCISAL ANGLE : PRIMARY INCISORS- 150 O PERMANENT INCISORS- 123 O www.indiandentalacademy.com
  16. 16. 2. INTER- TRANSITIONAL PERIOD  LASTS FOR AROUND 1.5 YEARS  RELATIVELY STABLE PHASE WITH NO CHANGES OCCURING IN THE DENTITION  TEETH PRESENT ARE PERMANENT INCISORS & 1 ST MOLARS ALONG WITH DECIDUOUS CANINES & MOLARS www.indiandentalacademy.com
  17. 17. 3. SECOND TRANSITIONAL PERIOD CHARACTERIZED BY :  REPLACEMENT OF DECIDUOUS MOLARS & CANINES BY PERMANENT PREMOLARS & CUSPIDS RESPECTIVELY  BEGINS AT AROUND 10 YEARS OF AGE www.indiandentalacademy.com
  18. 18. UGLY DUCKLING STAGE  This is a particular situation seen at around 8-9 years of age during the eruption of Permanent canines. As the developing permanent canines erupt, they displace the roots of the lateral incisors Mesially.  This results in transmitting of force on the roots of the central incisors which also get displaced mesially.  A resultant distal divergence of the crowns of the 2 central incisors causes a midline spacing. www.indiandentalacademy.com
  19. 19.  Ugly duckling stage has been described by BROADBENT as during this stage children tend to look ugly  This condition usually corrects by itself when canines erupt & the pressure is transferred from the roots to the coronal areas of the incisors www.indiandentalacademy.com
  20. 20. DEVELOPMENT OF PERMANENT DENTITION  PERMANENT DENTITION FORMS WITHIN THE JAWS SOON AFTER BIRTH EXCEPT FOR CUSPS OF 1 ST PERMANENT MOLARS WHICH FORM BEFORE BIRTH  PERMANENT INCISORS DEVELOP LINGUAL OR PALATAL TO DECIDUOUS INCISORS  THE PREMOLARS DEVELOP BELOW THE DIVERGING ROOTS OF DECIDUOUS MOLARS www.indiandentalacademy.com
  21. 21.  CALCIFICATION BEGINS AT BIRTH WITH THE CALCIFICATION OF CUSPS OF 1 ST PERMANENT MOLARS & EXTENDS AS LATE AS THE 25 TH YR OF LIFE  COMPLETE CALCIFICATION OF INCISOR CROWNS TAKES PLACE BY 4-5 YRS & OF OTHER PERMANENT TEETH BY 6-8 YRS EXCEPT FOR THE 3 RD MOLARS  AT APPROXIMATELY 13 YRS OF AGE ALL www.indiandentalacademy.com PERMANENT TEETH EXCEPT 3 RD MOLARS ARE
  22. 22. ERUPTION SEQUENCE OF PERMANENT DENTITION MAXILLARY ARCH: 6 – 1 - 2 – 4 – 5 – 3 – 7 – 8 OR 6 – 1 – 2 - 4 – 3 – 5 – 7 – 8 MANDIBULAR ARCH: 6 – 1 – 2 – 3 – 4 – 5 – 7 - 8 www.indiandentalacademy.com
  23. 23. www.indiandentalacademy.com
  24. 24. www.indiandentalacademy.com

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