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Growth of maxilla Pre and postnatal growth
- 1. Growth of maxilla ByDr Hadiqa Ayub Naz TMO ORTHODONTICS
- 2. According totodd Growth is an increase in size Change in propotion Progressive complexity
- 3. Mechanism of bonegrowth By three ways ; Bone deposition and resorption Cortical drift Displacement
- 4. Bone deposition andresorption Bone changes in size and shape by bone deposition and resorption and this phenomenon is called bone remodeling The changes that bone deposition and resorption produced are Change in size Change in shape Change in propotion Relationship of bone with adjacent structures
- 5. Cortical drift Acombination of bone deposition and resorption resulting in growth movement towards depositing surface is called cortical drift If both deposition and resorption are equal bone thickness remains constant In case if more bone is deposited on one side and less is resorpted on opposite side the thickness of bone increases
- 6. Displacement The movementof whole bone as a unit 2 types Primary displacement : This type of displacement occurs as a result of the bone's own growth. It involves the bone moving as a unit due to its own expansion and remodeling processes. For example, the growth of the maxilla at the tuberosity pushes the maxilla forward and downward against the cranial base
- 7. Secondary displacement ; This type of displacement occurs due to the growth of adjacent bones or surrounding tissues, not the bone itself. For example, the growth of the cranial base can cause the maxilla to move forward and downward, even if the maxilla itself isn't growing at that specific location
- 8. PRENATAL AND POSTNATALPERIODS Growth of an individual can be divided into : Prenatal and postnatal periods The PRENATAL can be arbitraliy divided into Period of ovum (2 weeks from time of fertilization ) Peripod of embroyo (14 day to 56 day of interuterine life) Period of fetus(56 day of interuterine life till birth )
- 9. Prenatal growth ofmaxilla The maxilla is attached to the neurocranium by circummaxilllary suture system and toward the midline by cartilaginous nasal cApasule ,nasal septum and vomer Anatomy of maxilla Parts of maxilla Four prosseses : Frontal Zygomatic Alveolar Palatine
- 11. Maxilla area pair of pneumatic bones and join together to form upper jaw They house the largest sinus in the body the maxillary sinus Each maxilla assist in forming the boundries of 3 cavities : The roof of the mouth The wall of orbit The floor and lateral wall of the nasal antrum
- 12. Prenatal embryology ofmaxilla Around 4 week OF IUL, the developing brain and pericardium form 2 prominent bulges on the ventral aspect of embryo ThEse bulges are separated by primitive oral cavity or stomodeum The floor of stomodeum is formed by buccophyrangeal memebrane which seperates it from foregut The mesoderm covering the developing forebrain proliferates and form downward projection that overlaps the upper part of the stomodeum The downward projection is called frontonasal process The phyrangeal arches are laid down on lateral and ventral aspects of cranial most part of foregut which lies in close approximation with stomodeum
- 16. Each ofthese arches give rise to muscels ,connective tissue ,vasculature,skeletal and neural components of future face Initially there are 6 phyrangeal arches but the 5 th one usually dissappeas as soon as it is formed The first arch is called mandibular arch The mandibular arches of both sides form lateral walls of stomodeum The mandibular arch gives off a bud from its dorsal end called the maxillary process The maxillary process grows ventromedially cranial to the main part of mandibular arch which is now called mandibular process At this stage the primitive mouth is overlapped from above by the frontal process below by the mandibular process and on either side by maxillary process
- 18. The ectodermoverlying the frontonasal process shows bilateral localized thickenings above stomodeum Theses are called nasal placodes these placodes soon sink and form nasal pits These pits divide frontonasal process into two parts medial and lateral nasal process The two mandibular processes grow medially and fuse to form the lower lip and lower jaw
- 20. As themaxillary processes under grows growth the fronronasal process become narrow so that the two nasal pits comes closer The line of fusion of maxillary process with medial nasal prosses coressonds to nasolacrimalduct
- 22. DEVELOPMENT OF PALATE Palate is formed by ‘ Maxillary process Frontonasal process 2 palatal shelves
- 24. Primary palate At the end of 5 week Develops from deep part of intermaxillary segment of the maxilla By the fusion of maxillary and nasal prosseses in the roof of stomodeum
- 26. Secondary palate Begins to develop in 6 week from shelves like stuctures called lateral palatine process Primodium of hard and soft palate posterior to incisive foramen Characterized by formation of palatal shelves on the maxillary process
- 27.
- 30. Ossification of maxilla Ossification within the midface starts at approximately 7 to 8 weeks gestation Develops in the mesenchyme of maxillary process INTARMEMBRANOUS OSSIFICATION
- 31. Primary ossificationcentre It lies between the division of inferior orbital nerve and the anterior superior nerve, just above the canine tooth dental lamina From this centre the bone spreads ; Posteriorly :below the orbit towards the developing zygoma Anteriorly :towards the future incisor region Superiorly :to form the frontal process
- 32. The secondaryossification centres are Zygomatic Nasopalatine Orbitnasal process Ossification spreads by ‘palatine process ‘and zygomatic processs
- 33. Develops fromthe centre of ossification in the mesenchyme of maxillary process No primary cartilage exist Centre of ossication is closely associated with cartilage of nasal capsule Primary centre of ossification develops near the division of inferior ortbital nerve into anterior superior alveolar nerve From the centre of ossification bone formation extends posteriorlty towards the developing zygoma and anteriorly toward the incisor region Ossication spreads posteriorly to form fontal process of maxilla
- 34. A bonytrough is form for inferior orbital nerve From this trough lateral alveolar plate forms for the develoing tooth germs Ossification spreads in the palatine process to form hard palate Medial alveolar plate develops from palatal process Medial and lateral alveolar plates form the trough for tooth germs
- 35. Post natal growthof maxilla Maxillary complex is attached to cranial base has a strong impact of growth of latter to former DISPLACEMENT THE DISPLACEMENT IN THE POSITION OF MAXILLARY COMPLEX Primary displacement : Growth of bone occurs due to its own growth which causes it to move from original position This occurs in forward direction This occurs by the growth of the maxillary tuberousity in the posterior direction this results in the whole maxilla being carried anteriorly
- 37. Secondary displacement Occurs inthe downward and forward direction as the cranial base grows Till the age of seven years
- 38. Growth atsutures ‘ Proliferation ,ossification ,surface apposition ,resorption and translation are the mechanisms of maxillary growth Maxilla is related to cranium at least by 5 sutures Frontonasal suture Frontomaxillary suture Zygomaticotempoeral suture Zygomaticomaxillary suture Ptergopalatine suture Thse sutures are oblique and more or less parallel to each other the growth in thess areas would serve to ,move the maxilla downward and forward
- 39. PREMAXILLARY suturefuses at approximately 3 to 5 years of age The midpalaatal and transpalatal sutures which are major intermaxillary growth sites associated with transverse and anteroposterior maxillary growth have been reprted to close between 15 to 18 years of age and 20 to 25 years of age respectively
- 41. SURFACE REMODELING Increase in size Change in shape Change in functional relation ship
- 43. Orbit:lateral surfaceof the orbital rim undergoes resoption PERMITTING lateral movement of eyeball. as a compensation there is bone deposition on medial rim of orbit and external surface of lateral rim. surface deposition occurs in orbital floor and as a result floor of the orbit faces superiorly, laterally & anteriorly.* MAXILLARY TUBEROSITY- bone deposition is seen along entire posterior margin of the maxillary tuberosity. this results in lengthening of dental arch and enlargement of antero-posterior dimension of entire maxilary body.thus posteriorly space for eruption of molars is provided.* THE ZYGOMATIC BONE- the zygomatic bone moves in a posterior and lateral direction. the posterior movement is achieved by resorption on the anterior surface and deposition on posterior surface. face enlarges in width by bone formation on lateral surface of zygomatic arch and resorption on its medial surface.
- 44. * NASALCAVITY PALATAL SIDE- size of nasal cavity increases with bone resorption on lateral wall of the nose. bone resorption is also seen on floor of nasal cavity. there is compensatory bone deposition on palatal side. net result is downward shift of palatal vault leading to increase in maxillary height.anterior nasal spine prominence increases due to bone deposition. in addition there is resorption from periosteal surface of labial cortex as compensatory, bone deposition occurs on endosteal surface of labial cortex and periosteal surface o lingual cortex. ALVEOLAR RIDGES: deposition occurs as teeth erupt. as of all permanent teeth, the teeth start erupting bone deposition occurs at alveolar margins. this increases the maxillary height and depth of the palate.* MAXILLARY SINUS- entire wall of sinus except mesial wall undergoesresorption. this results in increase in size of maxillary antrum. it appears as shallow groove during 4th month of iul, grows rapidly during 6-7 yrs and reaches full size after eruption.
- 46. Enlows V PRINCIPLE Enlows V principle was given by 1982 by Donald H enlow It is most useful and basic concept of facial growth According to V principle bone deposition occurs on inner side of V while resorption takes place on outside surface which leads to widening of V configuration At the same time the structure translates from its original position and move towards the wide end of V
- 47. The VPRINCIPLE is an important facial skeletal growth mechanism since many facial and cranial bones have V configuration or V SHAPED REGIONS THUS an increase in size and growth movement takes place in unified process Hence it is also called expanding V principle
- 48. Growth ofhard palate in coronal section shows resorption occurs on outer nasal surface and resorption occurs on inner palatal surface Progressive remodeling along with the growth at midpalatal suture and secondary displacement due to the growth of nasal bones increases the width of the palate and causes it to desends vertically downward
- 52. Length of maxilla Midface is displaced anteriorly ,compensatory bony deposition occurs along the posterior margins of maxillary tuberosity resulting in increase in the lenghth of entire maxilla and of dental arches The posterior maxilla is the major modeling site that accounts for increase in lenghth ALL sutures except ptergopalatine causes increase in leghth of maxilla Apposition in alveolar process to accommodate the eruption of teeth also increases height Nasal cartilage has growth potential innate which pushes maxilla downward
- 53. Increase in width Growth in median suture plays important role in increase in width The width of the midface at time of birth is large because of precocious development of eyes which are central features of neonatal face ‘ Growth in width occurs due to expansion of brain laterally and anteriorposteriorly which brings eyes latearlly with it At the time midface increase in width it also increasing dramatically in depth anteriorly and height posteriorly
- 54. Depth of maxilla The depth is increase by apposition in maxillary tuberosity also accelerated by sutural growth in pterogopalatine suture Midface increases more in height next in depth and least in width
- 55. Clinical significance ofmaxilla maxilla is formed from first branchial arch. any etiological factors which interfere with formation of this structure may give rise to underdeveloped maxilla maxilla forms middle-one third of face, underdevelopment of maxilla leads to midface deficiency particularly if nasal septum is involved maxilla is major site of cleft formation, particularly cleft lip and palate. maxilla is surrounded by envelope of facial muscles. restricted growth of this muscular envelope will retard the growth of maxilla.
- 56. .normal functionand development of dentition is a must for proper development of alveolar bone. anything that interferes with development of teeth may affect the alveolar bone and vertical height of maxilla. maxilla is related to cranial base by an angle of 82°. values less than this results in retrognathic maxilla and class 3 contions whereas value greater than this gives rise to prognathic maxilla and class 2 conditions. - maxilla follows somatic growth pattern. growth spurts are utilized for myofunctional and orthopedic appliances. they have their effect on maxillary sutures orthognathic surgery for maxillary skeletal problems is taken when active growth is completed
- 57. * verticallengthening of maxilla is equal in both anterior and posterior regions. if anterior vertical height is in excess,, it may result in anterior deep bite and gummy smile whereas decreased anterior height results in open bite.