Orthodontic Growth Assessment and Clinical Examination

Methods of Assessing Growth

• Physiologic Markers: Height and weight have limited predictive value for future growth rates.
• Pubertal Markers: Voice deepening (males) and menarche/breast development (females) are accurate but not applicable in dental clinics.
• Chronological Age: Girls (11.13 years) and boys (13.15 years) are convenient but do not correlate well with skeletal maturation.
• Dental Age: Panoramic X-rays show a weak correlation with puberty.
• Biological Skeletal Age (Most Accurate):
  • Skeletal Maturation Index (SMI): Uses adductor sesamoid via left-hand radiographs.
  • Cervical Vertebral Maturation Index (CVMI): Uses lateral cephalometric X-rays; CVMI 2 corresponds to SMI stage 4.

Concepts of Craniofacial Growth

• Cortical Drift: Bone deposition occurs in the direction of growth, with resorption on the opposite side.
• Mosaic Pattern: Outside and inside bone surfaces undergo continuous deposition and resorption.
• Bone Composition: Facial and cranial bones derive half their cortical bone from endosteal and half from periosteal sources.
• Functional Matrix Theory: Growth is controlled by the soft tissue matrix (e.g., mouth breathing leads to facial elongation).
• Growth Centers: High-rate growth areas include facial and cranial sutures, mandibular condyle, maxillary tuberosity, alveolar bone, and cranial base synchondroses (spheno-occipital, spheno-ethmoidal, intersphenoidal, and intra-occipital).
• Relocation and Remodeling: Relocation is the sequential movement of bone components in the direction of growth. Remodeling involves reshaping and resizing (e.g., mandibular ramus relocation and maxillary nasal chamber enlargement).
• Primary Displacement: Physical movement of the whole bone as it grows and remodels (e.g., nasomaxillary complex).
• Secondary Displacement: Movement of a whole bone caused by the enlargement of a nearby bone.

Smile Analysis and Functional Examination

Types of Smiles

• Spontaneous: Involuntary, dynamic, unsustainable, unstrained, emotionally induced, involving all facial muscles.
• Posed Smile: Voluntary and static.

Smile Assessment Criteria

1. Midline and smile symmetry
2. Smile line
3. Buccal corridor
4. Frontal occlusal plane
5. Upper lip curvature
6. Smile arc
7. Dental components
8. Gingival components

Functional Examination

• Mastication and Swallowing:
  • Somatic swallowing: Relaxed muscles, teeth in occlusion, tongue remains in the palate.
  • Visceral swallowing: Tongue thrust between teeth, no occlusion, contraction of orofacial muscles.
• Respiration: Assessed via double-sided mirror.
• Speech and TMJ: Evaluated through palpation and auscultation.

Uses of Orthodontic Study Models

1. Record dental anatomy
2. View occlusion from the lingual aspect
3. Assess arch form and symmetry
4. Evaluate occlusal curves
5. Analyze occlusion
6. Measure treatment progress
7. Detect abnormalities
8. Calculate total space
9. Provide permanent records
10. Facilitate research studies