Chapter 10: Growth and Development/Management of the Developing Occlusion Flashcards
Two types of bone formation
Endochondral
Intramembranous
Endochondral bone formation
Bony replacement of cartilaginous precursors
Cranial bse and condyle of the mandible
Less modifiable in context of dentofacial orthopedics
Intramembranous bone formation
Secretion of bone matrix without cartilaginous precursors
Facial bones (maxilla, body of mandible)
More modifiable in context of dentofacial orthopedics
Does bone apposition occur in osteogenic areas under pressure or under tension?
Under tension
Growth of the Cranial Vault
Formed by intramembranous ossification
Apposition of new bone primarily at sutures
Remodeling on inner and outer surfaces of bones to allow for changes in contour
Growth of the Cranial Base
Formed by endochondral ossification
Bony replacement primarily at synchondroses
Spheno-occipital considered principal growth cartilage of cranial base and only one remaining active in childhood growth period
Growth of the Maxilla
Formed by intramembranous ossification
Apposition in superior and posterior sutures of maxilla
Resorption on anterior surface of maxilla
Balanced apposition and resorption
Appositional growth occurs up and back against cranial base with growth expressed down and forward
Growth of the Mandible
Formed by endochonral ossification at condyle, intramembranous at body
Endochondral replacement at fibrocartilage of condyle
Appositional growth predominates along posterior border of ramus, remodeling along anterior border
Appositional growth occurs up and back against glenoid fossa, with growth expressed downward and forward
How much sooner do females reach skeletal maturity compared to males?
2 years earlier on average
Female growth spurt
Starts at approximately 10.5-11 years
Peaks 14-18 months later (12-13 years)
Complete by about 13.5-14 years of age
Male growth spurt
Starts at approximately 12.5-13.5 years
Peaks in 18-24 months (14-16 years)
Complete by about 17-18 years of age
Hypodivergent/brachyfacial facial form
Posterior face height proportionately greater than anterior face height
Flat mandibular plane, pronounced overbite
Hyperdivergent/dolichofacial
Anterior vertical facial growth greater than posterior condylar growth
Steep mandibular plane with open bite tendency
Vertical dimension growth
Nasion-menton
70% complete by age 3; 90% by adolescent growth spurt
Transverse dimension growth (facial width)
The least amount of change of any facial dimension
Upper face width increases during childhood and adolescence with greatest rate observed between 2-6 years
Lower face width 85% complete by time first molars erupt
Anteroposterior dimension growth (facial depth)
Longest growing facial dimension
Greater mandibular increments allow profile to change from convex in childhood to straighter adult profile
Airway compromise/mouthbreathing impact on growth
May compromise facial growth
Increase vertical orientation
Similar occlusion changes as with extraoral habits
Management of mouthbreathing
Distinguish from extraoral habits
If airway related, refer to ENT assessment for allergy management, tonsillectomy/adenoidectomy followed by palatal expansion
Is there a recognized or specific standard for what type of diagnostic records are necessary for orthodontic problems?
No
General agreement that proper assessment includes questionnaire of patient, examination, as well as diagnostic records
2016 AAO list of pretreatment unaltered diagnostic records needed for comprehensive orthodontic treatment
Intra and extraoral images
Dental models of maxillary and mandibular arch
Intraoral and/or panoramic radiographs
Cephalometric radiographs, with CBCT used as alternative when necessary
Periodic radiographic assessment, such as panoramic, is recommended at what intervals during ortho treatment?
6-12 months
Recommended due to major problems such s external apical root resorption
Ceph: Maxilla to cranium
SNA
A point to Nasion
Ceph: Mandible to cranium
SNB
Pogonion to Nasion
Ceph: Maxilla to mandible
ANB
Mx-Mn length difference