Growth and Orthodontic Treatment Flashcards
(35 cards)
What is the definition of growth?
An increase in size and number
What is the definition of development?
Implies an increase in specialisation or function
What is the definition of growth centre?
Where independent growth occurs (genetically determined)
What is the definition of endochondral ossification?
Bone develops from cartilaginous precursor, seen in the long bones of the limbs and cranial base
What is the definition of intramembranous ossification?
Bone is formed by osteoblasts present in mesenchymal tissue
Takes place in mandible, maxilla and cranial vault
What is the definition of surface remodelling?
Process of resorption and deposition of bone which allows the size and shape of facial bones to change
Describe the definition of primary displacement
Change in position is caused by bone itself changing in size
Describe the definition of secondary displacement
Caused by the growth of an adjacent bone - such as in the change in the position of maxilla due to growth of the cranial base
Name 2 components which controls the timing and extent of growth
- Genetics
2. Environment
Describe Moss’s Functional Matrix Theory
Growth of the face is determined by growth of soft tissues i.e orbit increases as eye grows, cranium increases as brain grows
Describe the Cartilagenous Theory of craniofacial growth
Proposes cartilage as the primary determinant of growth
Describe the implications of growth on orthodontic treatment
- Majority of orthodontic treatment carried out on individuals who are growing
- Many authorities studying growth emphasis variation in amount and direction of growth
Name 3 growth problems which may be present in orthodontic cases
- Severe skeletal II (insufficient growth of mandible)
- Severe skeletal III (excess growth on mandible)
- Severe skeletal open bites (excess vertical growth)
Describe 4 headings under which orthodontic implications of growth may be consdiered
- What changes are likely due to growth?
- Can the orthodontist influence growth?
- Can the orthodontist make use of growth?
- Growth prediction
Describe growth of the cranial vault
- Cranial vault composed of squamous parts of parietal, frontal, temporal and occipital bones
- Cranium grows as brain grows
- Growth is sutural and appositional
- All intramembranous growth
Name 4 components of the cranial base
- Occipital
- Sphenoid
- Ethmoid
- Frontal
Name 2 pieces of chondrocranium present at birth
- Spheno-occipital synchrondrosis
2. Nasal cartilage
Describe the growth of the cranial base
- Anterior cranial base (apart from thickness of frontal bone) is finished growing at around 8-10 years
- Area used as reference to evaluate growth in other areas
- Base grows in intermediate fashion between calvarium and face
Describe how the bones are arranged to make up the cranial base, including explanations of anterior and posterior
- Anterior base is made up of frontal, ethmoid and anterior part of sphenoid and includes the SES (fuses 6-7 years)
- Posterior base is made up of posterior part of sphenoid and occipital and includes SOS (grows until 13-15F / 15-17M)
Describe maxillary growth
- Predominant enlargement is posterior and superior, with downward and forward displacement
- Processes are primary and secondary displacement, intramembranous ossification and surface remodelling
- Deposition of bone on ridges increases face height
Describe the effect of teeth on maxillary growth
- Growth is reduced without presence of teeth
- Mouth breathing where teeth are not in contact or edentulous patients will show reduced vertical growth
Describe 3 types of maxillary growth which occurs
- Maxillary displacement
- Tuberosity growth (increase arch length for molars)
- Inferior relocation of palate
Describe the V-principle of growth
Infiltrating bone in the middle of the palate causes lateral displacement of bone which widens the arch
Describe condylar growth
- Site of growth but not growth centre
- Condyle does not establish rate or amount of growth
- It is adaptive
