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PRENATAL AND POSTNATAL DEVELOPMENT OF MAX AND MANDIBLE.pptx
The development of the maxilla and mandible is a complex, highly regulated process that begins early in embryogenesis and continues through various postnatal stages until adulthood. This presentation explores both prenatal and postnatal aspects of jaw development, emphasizing their anatomical, embryological, physiological, and clinical significance. The jaws, derived from the first pharyngeal arch, play a pivotal role in shaping facial features, enabling mastication, respiration, phonation, and proper dental alignment. A sound understanding of the development of these structures is fundamental for dental professionals, maxillofacial surgeons, orthodontists, and embryologists, as it forms the basis for diagnosing and managing various craniofacial anomalies and growth disturbances. Prenatally, development begins with the migration of neural crest cells from the neuroectoderm of the midbrain and hindbrain regions to the facial region. These cells contribute significantly to the mesenchyme of the first pharyngeal arch, which ultimately gives rise to the maxillary and mandibular prominences. During the 4th to 8th weeks of intrauterine life, these prominences undergo extensive cellular differentiation and morphogenesis. The maxillary process fuses medially with the medial nasal process to contribute to the upper jaw, including the maxilla, while the mandibular process merges at the midline to form the lower jaw or mandible. The ossification of the mandible begins earlier than the maxilla, typically around the 6th week of intrauterine life. It follows the pattern of intramembranous ossification, although the condylar, coronoid, and symphyseal regions may involve endochondral ossification. The Meckel’s cartilage, although not directly converting into bone, serves as a template and contributes to the formation of structures such as the malleus and incus in the middle ear, as well as ligaments. The maxilla, on the other hand, also develops via intramembranous ossification and is closely related to the cartilaginous nasal capsule. The zygomatic process, frontal process, palatine process, and alveolar process begin to form distinctly, coordinating with the development of primary and secondary palates. During the fetal period, both jaws continue to grow and are shaped by the influence of genetic and environmental factors, including the position of the developing tooth buds, muscle attachments, intrauterine pressure, and functional movements of the fetus. The early development of alveolar ridges and sockets provides the foundation for the future dentition. The growth of the mandible is influenced significantly by the condylar cartilage, which acts as a secondary cartilage and remains active until adolescence. This is crucial for understanding how mandibular growth occurs in multiple directions—downward, forward, and laterally. At birth, the maxilla and mandible are underdeveloped compared to their adult form. The mandibular angle is obtuse, the body .
PRENATAL AND POSTNATAL DEVELOPMENT OF MAX AND MANDIBLE.pptx
- 1. GOOD MORNING DR.SHEETAL SCHAVAN PG 1ST YEAR DEPARTMENT OF PUBLIC HEALTH DENTISTRY
- 2. Prenatal and postnatal developmentof Maxilla and Mandible
- 3. Contents Prenatal and postnatal period Development of maxilla Palate and its Development Prenatal and postnatal development of mandible Anomalies of maxilla and mandible Conclusion refrences
- 8. Prenatal period Period ofovum - Fertilization to 2 weeks Period of Embryo - 2nd to 8th week Period of fetus - 9th week to term
- 9. Anatomy of themaxilla Parts of Maxilla • 1. Body-Large Pyramidal Shape • 2.Four Processes Frontal Zygomatic Alveolar Palatine Maxilla houses the largest sinus of the face, the maxillary sinus
- 10.
- 11. Ossification of maxillabegins slightly later than in the mandible. The premaxilla begins to ossify from two centers in the latter part of 7th week. Ossification spreads by Bony trough formed for infraorbital nerve and Palatine Process. Maxillary sinus – 16th week.
- 12. Postnatal Development ofMaxilla The growth of the Naso-maxillary Complex is Produced by following mechanism Displacement Growth at Sutures Surface Remodelling
- 13. Displacement. Leads to opposition of boneat sutures Displacement Primary Secondary
- 14. Primary Displacement When the bonegets displaced as a result of its own growth.
- 15. Secondary Displacement Bone gets displacedas a result of growth and enlargement of a adjacent bone. It is physical movement of bone. Causing secondary deposition of bone at sutures. Downward and forward growth.
- 16. Growth at the sutures Themaxilla is connected to the cranium and cranial base by number of sutures. a. Fronto-nasal suture b. Fronto-maxillary suture c. Zygomatico –maxillary suture. d. Pterygo-Palatine Suture e. Zygomatico-Temporal Suture
- 17. • These suturesare all oblique and more or less Parallel to each other. • This allows the Downward and Forward Positioning of the maxilla as growth occurs at this sutures. • This leads to opening up of space at the sutural attachments. • The overall size of the bones increases on either side. • Hence a tension related bone formation occurs at the sutures.
- 18. Surface Remodeling • A. Increasein size • B. change in shape of bone • C. change in functional relationship In addition to occurring at the sutures. Massive remodeling by bone deposition and resorption occurs to bring about
- 19. The following arethe bone remodeling changes that are seen in the naso- maxillary complex 1.Bone deposition occurs along the posterior margin of the maxillary tuberosity. They cause the lengthening of the dental arch and enlargement of antero-posterior dimension of entire maxillary body this help to accommodate the erupting molars.
- 20. Bone resorption occurson the lateral wall of the nose leading to increase in the size of nasal cavity. Entire wall of the sinus expect mesial wall undergoes resorption this results in increase in size of maxillary antrum.
- 21. Bone resorption isseen on floor of nasal cavity to compensate deposition on palatal side thus net downward shift occurs leading to increase in maxillary height.
- 22. As the teethstart erupting bone deposition occurs at the alveolar margin increase maxillary height and depth of palate.
- 23. Growth at height-Vertical Growth in width- Transverse Growth in Length-A-P
- 24. Vertical Dimension (InHeight) Palatal Remodeling Eruption of teeth Primary displacement
- 25. Transverse direction (Inwidth) Growth in midpalatine suture Remodeling at lateral surface of alveolar processes
- 26. A-P Dimension (Inlength) Maxillary tuberosity Palatomaxillary suture Primary and secondary displacement
- 27. Palate Ossification • Ossification ofpalate occurs from 8th week of intrauterine life. • This is intramembranous type of ossification • The palate ossifies from single center derived from the maxilla • The most posterior part of the palate does not ossify: This forms the soft palate • The mid-Palatal sutures ossifies by 12-14 years.
- 28. Fusion of mediannasal prominences with contralateral side creates intermaxillary segment. The maxillary Prominences expand medially to give rise to palatal shelves PRIMARY PALATE (becomes anterior 1/3rd of definitive palate) Philtrum Upper Four Incisors Mandible prominences expand. Palatal shelves then fuse with each other in horizontal plane and nasal septum in vertical plane, forming secondary palate.
- 29. Musculature of palate Tensorveli palatini 40 days 1st arch Palatopharyngeous 45 days Levator veli palatini 8th week 2nd arch Palatoglossus 9th week Uvular muscles 9th week 2nd arch
- 30. Growth in dimensionsof palate • Prenatal life (Oppositional growth in the alveolar margin) length>width • At birth (Oppositional Growth in maxillary tuberosity) Length=Width • Post natal life Width>Length • Length increases- 7-18weeks IUL • Width increases-4th month onwards
- 31. Growth at midpalatal suture ceases at 1-2 years Apposition inner surface of Alveolar Process Resorption –Superior surface
- 32. Factors affecting growthof palate Elevation of head and lower jaw Oxygen and nutritional deficiency Excess endocrine substances Drugs Irradiation Vascularity
- 33. Prenatal and postnatal developmentof Mandible
- 34.
- 35. Condylar Process About the 5th weekof IUL a area of mesenchymal condensation can be seen above the ventral of developing mandible. This develops into a cone-shaped cartilage by about 10th week and starts ossification by 14th week. Then migrates inferiorly and fuses with the mandibular ramus by about 4th month.
- 36. Coronoid Process Secondary accessory cartilages appearin the region of the coronoid process by about 10-14th week of IUL Coronoid process
- 37. Mental Region In this region,on the either side of the symphysis, or two small cartilages appear and ossify in the 7th month of IUL to form a variable numbers of mental ossicles in the fibrous tissue of the symphysis Mental region
- 38. Postnatal Growth ofmandible • While the mandible appears in the adult as single bone; • It is developmentally and functionally divisible into several skeletal sub unit. • Basal Bone Forms one unit, to which is attached the alveolar process, coronoid process, condylar process, angular process, the ramus, the lingual tuberosity and the chin.
- 39. Ramus • It movesProgressively Posteriorly by a combination of deposition and resorption. • Resorption Occurs on anterior Part of ramus and Deposition occurs on the posterior region. • This results Drift in posterior direction.
- 40. Functions Of remodelingof ramus are: To accommodate the increasing mass of masticatory muscles inserted into it To accommodate the enlarged breadth of pharyngeal space. To facilitate the lengthening of the mandibular body, Which in turn accommodates erupting molars
- 41. Corpus or thebody of the mandible • Displacement of the ramus results in the conversation of the ramal bone into the posterior part of the mandible. • In this manner It lengthens. Thus additional space made available by means of resorption of the anterior border of ramus is made use of to accommodate the erupting molar.
- 42. Angle of themandible • On the lingual side of the angle of the mandible, • Resorption take place on the Postero-inferior aspect while • Deposition on the antero-posterior aspect. • On the buccal side resorption occur on the antero-superior part while deposition takes place on posterior-superior part. • This results in flaring of the angle of mandible as age advances.
- 43. Alveolar process • Itdevelops in response to the presence of tooth buds. • As the teeth erupt, It develops and increase in height by bone deposition at the margin.
- 44. The chin • Asthe age advances the growth of chin becomes significant. • It is influenced by sexual and specific genetic factors • Usually males are seen to have prominent chin as compared to females. • Mental tuberosity forms by bone deposition during childhood.
- 45. The Condyle • Thehead of condyle is covered by the thin layer of cartilage called condylar cartilage. • The presence of cartilage is an adaptation to withstand the compression that occurs at the joint. • It is believed that the growth of the soft tissue including the muscles and connective tissues carries the mandible forward away from cranial base. • Bone growth follows secondary at the condyle to maintain constant contact with the cranial base • The condylar growth rate increases at puberty reaching a peak between 12 -14 years • The growth ceases around 20 years of age.
- 46. The coronoid process •The growth follows ‘V’ Principle. • Viewing the longitudinal section of coronoid process from posterior aspect, it can be seen that deposition occurs on lingual surface of the left and right coronoid process. • Although addition take places on lingual side, the vertical dimension of coronoid process also increases. • Viewing from the occlusal aspect, the deposition on lingual of coronoid process brigs about posterior growth movement in V pattern.
- 47. Anomalies of Maxilla, palateand Mandible.
- 48. Cleft Lip andcleft palate • It is a most common congenital malformation. • Failure in the fusion of nasal and maxillary process leads to cleft of primary palate. • It can be unilateral or bilateral. • Incidence of cleft lip and palate varies from 1 in 500 to 1 in 2500 depends on geographic origin.
- 49. A cleft =Gap /split in the upper lip or palate A cleft lip- Medial nasal promiance and maxillary prominence fail to fuse Cleft Palate- Palatal shelves fail to fuse in the midline or in combination with cleft lip
- 50. Clinical features Sex: Male>Female Lesion: Unilateral or Bilateral anomaly The cleft anterior to the incisive foramen is defined as cleft primary palate. The cleft posterior to the incisive foramen is defined as a cleft of secondary palate.
- 51. Etiology Heredity Environmental factors Insufficient nutritionto pregnant women Other Factors Defective Vascular supply Size of tongue Prevent union of affected parts Infection, certain alcohol, drugs and toxins Lack of inherent developmental force
- 52. Clinical significance • Mostof cases can be surgically repaired with excellent cosmetic and functional results. • Eating and drinking are difficult because of regurgitation of food and liquid through the nose
- 53. Uranoschisis-cleft of hardpalate Staphyloschisis-Cleft of soft palate
- 54. Cleft Jaw Non fusionof the globular processes with the maxillary processes or non union of the 2 mandibular processes forming the so called true median cleft
- 55. Microstomi a Abnormally small mouthdue to excessive merging of the mandibular and maxillary processes.
- 56. Macrostomia Big mouth resultingfrom incomplete union of the maxillary and mandibular processes may also be called cleft of the cheek.
- 57. Conclusion • Importance ofgrowth is that it is the indicator of general health. • It helps to identify unusual growth patterns at early stage • Growth effects stability and occlusion • Etiology of development of malocclusion • Growth spurts
- 58. Referances • Singh G,editor. Textbook of orthodontics. JP Medical Ltd; 2015 Feb 20. • Singh V. Textbook of Clinical Embroyology. Elsevier India; 2012. • O’Brien K, Stephens C. Obituary: Professor William Robert Proffit. Journal of orthodontics. 2019 Mar;46(1):87-. • Been W, SH LK, Van Limborgh J. Developmental anomalies of the lower face and the hyoid cartilage due to partial elimination of the posterior mesencephalic and anterior rhombencephalic neural crest in chick embryos. Acta Morphologica Neerlando-scandinavica. 1984 Dec 1;22(4):265-78.
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