2. áá¬áááá¬
1. Introduction to Orthodontics 1
2. Development of Normal Occlusion 8
3. Growth and Development 17
4. Face Development in Orthodontics 20
5. Development of the dentition 23
6. Clinical Examination in Orthodontics 29
7. Cephalometric analysis 35
8. Soft tissue analysis 41
9. Etiology of malocclusion in orthodontics 46
10. Tooth Movement 51
11. Orthodontic Movements 54
12. Orthodontic Records 59
13. Anchorage in Orthodontics 63
14. Diagnosis and Treatment Planning 68
15. Crowding 79
16. Maxillary midline diastema 83
17. Crossbite 86
18. Fixed appliances in Orthodontics 89
19. Timing of Orthodontic Treatment 95
20. The pre-adjusted edgewise (straight wire) appliance 98
21. Growth and Development 101
22. Biomechanics 103
23. Orthodontic instruments, materials and equipments 107
24. Malocclusion 127
25. Class I Malocclusion 136
26. Class II division malocclusion 143
27. Class II division 2 malocclusion 152
28. Class III malocclusion 158
29. Introduction to Fixed appliance 167
30. Retention, Retainers and Relapse 180
31. Risks of Orthodontic Treatment 190
21. á¡áá±ážááá¯á±ážááá±ážááœá±á¬á±ážá¡áá á¥á±á¬áºáᬠááá±á¬áºá¡áá á±á¬áºá¡ááœá±á á²á· ááááá±á¬áºá±ážáááá±á¬áºá±ážááá±ážááœá±á¬á±ážáá¬áá²á· áá±á¬áºá¡áááá±á¬áºá±ážá á²á· ááá±á¬áº
á¡á¡áá¬áá±á¬áºá±ážá¡ááœá± ááááá±á¬áºá±ážáááá±á¬áºá±ážá¡á á¬á²á·áá¬áá²á· áá±á¬áºá¡áááá±á¬áºá±ážááᯠá±áž (á) áá¯áá±á¬áºá±áž á¡ááœá±áœá¶á·á á«ááá±á¬áºá Ramus á á²á·posterior border
áᬠááá±á¬áºá¡áá á±á¬áºá¡ááœá±á á²á· ááá±ážááœá±á¬á±ážááŸá¯ááá±á¬áºááá á±á¬áºáᬠá«ááá±á¬áºá Ramus á á²á·anterior border áᬠááá±á¬áºá¡á¡áá¬áá±á¬áºá±ážá¡ááœá±
á¡ á¬áá±á¬áºááœá±áá±á¬áºáᬠá«ááá±á¬áºá Mental protuberance á á²á·
á¡ááá±á¬áºáᬠbone resorption ááá á±á¬áºáá¬áá²á·á¡áá« á¡á áá²á·á±á¬áºá¡áá±áž
ááá á±á¬áºáá¬áá¬ááᯠá¡ááœá±áœá¶á·á á«ááá±á¬áºá
ááœá±á¬á±ážáááá¯áá°áá¬á¡ááœá±ááᯠááá¯áááŸá¯á¡ á±ážáá²á·á¡áá« á¡áá¬áá á¬á±ážá¡áá±ážá á²á·
ááá±á¬áºá±ážáá¡áá±ážá¡ááœá±á á²á· growth spurt ááá¯
ááá¬á±ážááá²á·á±á¬áº á«ááá±á¬áºá
Boys Girls
⢠12.5 â 15 years old (average 14 year)
⢠Max velocity is 10 cm/ year
⢠Results in height increase of 20 cm and
weight increase of 20 kg
⢠Principal hormone is testosterone but
some estradiol may be converted from
testosterone
⢠10.5 â 13 years old (average 12 years)
⢠Max velocity is 8 cm/ year
⢠Results in height increase of 20 cm and
weight increase of 16 kg
⢠Principal hormone is estradiol but some
testosterone may be converted from
androstenedione
Note: Nutrition is the most important environmental determinant of growth. Mostly affected by
malnutrition is muscles and fat, then bones, then teeth.
áá¡áá±ážá¡ááœá±á á²á·
á¡ááá±á¬áºááᯠáá±á¬áºááᯠááá±á¬áºááá±á¬áºá áá±á¬áºá¡ááœá±á á²á· ááá²á·á±á¬áºááá¯áá±á¬áºáá?
Skeletal age = based on ossification of bones [mostly assessed by radiographs of the hands and wrists
compared to an atlas of radiographs that covers the entire developmental period]
Dental age = based on tooth formation + eruption [degree of cusp/root calcification, development of
the roots, closure of the apical foramen, emergence (penetration of the gingiva), eruption (contacting
the opposing tooth) is assessed]
Simplest way to determine age is to look for the number of teeth erupted and the sequence of eruption
Morphological age = based on height
Sexual = based on development of sexual features
19
32. Extra-oral Assessment
Assessment of skeletal pattern
Anteroposterior dimension
áááá¥á±ážáá¶áá¯á±áž áá°áá¬ááᯠnatural head position (standardized and reproducible) áᬠáá¬á±ážáááá²á·áºááá«áááºá
Natural head position ááá¯áᬠáá°áá¬ááᯠáááºáááºááá¯ááºááá¯ááºá±ážá ááºá á¬áá²á·áº áẠá¬áááá ááá±áž áá°áá¬áá² á²á·
áá»ááºáá¶áá¯á±ážáá² á²á·
áá áºáááºá±ážáááºá±áž áááŸá±á·áááºáá¬ááááá²á²á· point áá áºááá¯ááᯠáááá²á·áºááá¯ááºá±ážáá¬á±ážáᬠááá áºáá«áááºá áœá±á¬á±ážáááœá±ááá¯áááºá±áž
á¡á¶ááááºáááá¬áá»áŒá¯á±ážáááá¯ááºáá² áá¶áá¯áááºá¡ááá¡áá¬á±áž áá¬á±ážááá«áááºá (Teeth should be slightly in occlusion.)
áá°áá¬áá² á²á· á¡ááá±á«áº áá² á²á·
áá¡á¬ááºááá±ážááá¯á±ážáááœá±áá² á²á· áááŸá±á·áááºá¡áá»áá¶áá¯á±ážá¡áááºáááœá±ááᯠá¡ááá±á«áºááŸá¯ááºáááºá±ážáá² á²á· áá¡á¬ááº
ááŸá¯ááºáááºá±ážáááœá±áá² á²á·
á¡áááááááá²á·áº áá¶áá¯áᬠáááá¬á±ážáá²á²á·á¡ááá¯ááºá±áž á ááºá±ážáááá²á·áºááá¯ááºáá«áááºá
Class I The mandible lies 2-3 mm posterior to the maxilla [the straight profile]
Class II The mandible lies retrusive to the maxilla [convex profile]
Class III The mandible lies protrusive to the maxilla [concave profile]
áá°áá¬áá² á²á·anterior limit of cranial base ááᯠááá¯ááºá á¬á±ážáááŒá¯áá²á²á· zero meridian line ááœá±á²áááá²á·áºááá±áž soft tissue A
point, soft tissue B point áááœá±áá² á²á·ááŸá¯ááºá±ážáá¥áºáááá²á·áºááá¯ááºáá«áááºá áá¶áá¯áááºááá¯ááẠsoft tissue A point á álineáá² á²á·áááŸá±á·áááº
2-3mmá¡ááœá±á¬áᬠáááá±áž soft tissue B point á álineáá² á²á·ááá¬ááºááẠ0-2mmá¡ááœá±á¬áᬠááááááºáá«áááºá
(a) The Ricketts zero-meridian line is a constructed vertical line dropped perpendicular to the Frankfort Plane (or horizontal) from Nâ. It
gives an indication of the antero-posterior position of Pgâ, which will lie behind the line in class II cases with mandibular retrusion (b) and
in front in cases with mandibular prognathism (c).
30
35. Lip fullness and tone
Lip competency
A. Competent lips: a lip seal is produced with minimal muscular effort when the mandible is at
rest position
B. Potentially competent: positioning of the upper incisors prevents a comfortable lip seal
C. Incompetent: excessive muscular activity is required to achieve lip seal [the interlabial distance
at rest is >4mm]
Signs of excessive muscular activity
Flattening of the labio mental fold when the lips are held together
Puckering of the skin overlying the chin [due to the mentalis muscle contraction]
Method of achieving anterior oral seal at rest and at swallowing
á¡ááá±á«áºááŸá¯ááºáááºá±ážáá² á²á·áá¡á¬ááºááŸá¯ááºáááºá±ážáááœá±áᬠRickettâs esthetic line [E-line]áá² á²á·áááºááá¬ááºá¡ááœá±á¬á¡ááá±áž
áᬠááááá²ááá¯áá¬ááá¯áááºá±áž ááá¯ááºá±ážáááá²á·áºááá¯ááºáá«áááºá áá¶áá¯áááºááá¯ááẠupper lip áᬠE-lineáá² á²á·
ááá¬áẠ4mmá¡ááœá±á¬áá á²á·
áº
áᬠááá áá²á·áºááá±áž lower lip áᬠE-lineáá² á²á·
ááá¬áẠ0-2mmá¡ááœá±á¬áá á²á·
áºáᬠááá áá²á·áºáá«áááºá
áá°áá¬áá² á²á·upper lipáᬠáááºááá¯á¡ááá¡áá¬á±ážáá² á²á·
ááááá²ááá¯áá¬ááᯠáááá¯ááºááᯠá²á·Nasolabial angle ááá¯áááºá±áž
ááá¯ááºá±ážáááá²á·áºááá¯ááºáá«áááºá
Normal Nasolabial angle=102±8 Acute = <90 Obtuse = >90
33