Preventive Orthodontist 

• Stop prevent the dz from occurring 

• Education, oral hygiene, caries control, OCCLUSAL EQUILIBRIATION,

• X of Supernumerary Fovertetained teeth,

• Management of deeply locked 1st molar d/t muscosal barrier, 

• Habit breaking, 

• Ab(N) frenal attachment,

• Proximal stripping of the 1° teeth, 

• Space maintenance, 

• Mouth - guards.

Interceptive Orthodontics

• Interrupt the M/O from fully developing

• Measures taken to prevent & potential m/o from progressing into a more severe one.

• Correction of developing cross-bite.

Corrective Orthodontics

• Mastin Dewey → 1st editor of journal of American Journal of Orthodontics & wrote the book "Practical Orthodontics"

Jackson's triad

Basic Aim of Orthodontic Therapy

1. Functional efficiency (of masticatory system)

2. Structural balance  (b/w teeth & oral mucosa)

3. Esthetic harmony

4. Oral health related Quality of life (OHRQoL)

Why is M/O so prevalent?

Butlers field theory

• In each field, maximum variability occurs in the distal part and minimum in the mesial part

• Example: lateral incisor shows more variability than CI eg = peglaterals

• Evolutionary changes 

  • Decrease in teeth size

  • Decrease in jaw size

  • Decrease in number of teeth

  • Under developed jaw due to soft diet

• All of these contribute to increase prevalence of M/O.

• Face shows greater growth, pre-naturally

• Lower limb shows greater go post naturally

Maxilla being closer to the skull grows earlier than mandible

• Orthopedic applicane to correct max deficiency s/be given at a younger age as compared to mandibular appliance

  • Face mask is given earlier than twin block to correct class III m/o 

  • Headgear is given earlier than bionator to correct maxillary excess or to distallize maxila

Divider the Tissue into 4 types

1. Neutral tissue completes

   • 90% by 6 years

   • 96% 10 years and completes by 15-17 years

   • 100% by 20 years

2. Lymphoid Tissue

   • Involutes at puberty

     • 100% = 7 yrs

     • 200% =14 yrs

       • Clinically : mouth breathing, commonly seen at 10 to 12 years of age and starts decreasing at the start of pubertal growth spurt. 

3. Genital 

   • Begins at puberty

4.  Somatic

   • S shaped 

     • Increases at growth spurts

Que : the major tissue system of the body that is the earliest to complete its growth and development in the life is

• Muscular

• Neural

• Lymphatic

• Lymphoid

• Growth of the neutral tissue completed by 15 to 17 years

• Maximum growth of the neutral tissue is completed by 6 to 7 years

Que :  S - Shaped curve by general body tissue : Musclbone, Viscera

• Negative growth is seen by 

  • Lymphoid tissue eg : Adenoid Thymu

• Growth of 

  • Maxilla follows → Neural

  • Mandible follows →  General

• Growth of the jaw is similar to general body growth

Que : the acceleration of the general body growth at puberty, which affects the jaw parallels. The dynamics increases in development of sexual organ.

• Any myofunctional appliances to influence the growth of job given prior to puberty

Variability

• D/t genetic and environmental factors

• Not all people of population are like in growth, and it is important to decide whether which are at extreme of Ⓝ or fall outside the Ⓝ range

• Differentiate b/w Ⓝ and Ab Ⓝ growth is Variability

• A child falling beyond the 97 percentile needs to be studied further to check if the growth status is abnormal (Bell shaped graph)

• Variability in the growth can arise from

  1. Influence outside the normal experience 

     • e.g. serious illness

  2. Timing effect

     • Biological clock of every individual is set

Timing

• Growth Spurts

  • Period of increases growth activity

• Maximum rate of growth is seen from birth-1st year of life

• Phases of growth spurt

Phase I

• Period of accelerated skeletal growth, correspond to upswing phase as seen in growth curve

  • a/w rapid, increase in height in both female and male

    • Increase length of trunk

      • ♀ = 15 cm  

      • ♂ = 16.5 cm

  • PHV ♂ = 9.8 cm/yr (14 yrs); ♀ 8.1 cm/yr (12/13 yrs)

Phase II

• Growth decelerates from around three years

  • Growth of lower Limb

    • ♀ = 13-16 yrs 

    • ♂ = 15-18 yrs

• ♀ = Menarche occurs 1yr after PHV

  • Little or no skeletal growth occurs after onset of menarche

  • No use of giving functional application after this PD 

    • eg Twin Block → 1/1.5 yrs before onset of puberty

• Growth spurts come later in the male or there is longer growth pd in the male as compare to female

• Functional or growth modification appliances can be given at later, age in male as compared to female

Mini Growth Spurts

• Day-to-day variation in growth

• On every day basis → Exaggerated growth interspersed  ĉ time of the little or no growth → it is d/t the Rhythmic change in level of circulating hormones

When distance curve of boys and girls are compared girls crosses boys at 10 years of age that is beginning of pubertal growth, Spurt

At 10 to 13 years, girls, more than boys (height)

d/t earlier onset of pubertal growth spurt

Add 14 years, boys, more than girls (height)

Rate of growth is seen decrease from birth to adolescece f/by marked, increase in height during pubertal growth spurt 

aka CIRCUM PURERTAL ACCELERATION

Which of the following individual functional appliance

therapy can be started a at 10 yrs of age

m1= menarche ⟹ 10-12 yrs

m2= menarche ⟹ 12-13 yrs

m3= menarche ⟹ 13-15 yrs

1. m1

2. m2

3. m3

4. none

None : b/z functional application is given 1 to 1.5 years before the onset of menarche

First growth spurt after birth occurs in

1. First year

2. Third year

3. Sixth year

4. Ninth year

Method of studying physical growth

• Ant r aspects of symphysis

• 2 pins on right side of the basal part of the mandile under 1st & 2nd PM

• 1 pin on external aspect of the Rt ramus under the level of occlusal surface of the molars

• 1 or 2 pins : Mand base on left side under 2nd or 1st molar.

Im bone form cannot occur against pressure gradient b/z it is DEPENDENT ON PATENT BV along bone surface (So occur in area of TENSION only)

Fast & Direct Process

• Endochondral Ossification

  • Cranial base (SYNCHONDROSIS), Nasal Septum, Condyle & Coronoid process & a part of mental area.

• Both INTERSTITIAL & APPOSITIONAL growth 

  • (Bz of ⊕ence of its own patent Blood supply.)

• occurs at AREA of COMPRESSION

• Replacement of hyaline Cartilage c Bone. 

• Displacement 

  • Movement of the whole whole as a unit as bone remodel

  • Two types

• Note : Growth is composite of 1° & 2° displacement

• Drift main occur in SIMILAR or opposite DIRECTION as that of displacement