1. Prenatal development from orthodontic point of view. Flashcards
(25 cards)
Why should we know about craniofacial growth and development?
To identify the etiology of the malocclusion, to identify the pathological models of Growth, to conduct malocclusion prevention and modify the pathologic growth process, diagnosis, prognosis, treatment planning of malocclusion, to choose the proper time to start treatment, to understand the factors which affect the retention and stability of the treatment results.
What is Ontogenesis?
Individual development of human from birth to death; a short repetition of PHYLOGENESIS.
What are the periods of Ontogenesis according to Boyanov?
- Prenatal development (afunctional period)
- Postnatal development (functional period)
What occurs during the fertilisation stage?
Fusion of sex cells nuclei; parents’ traits are combined.
What is the embryonic period?
Development of human (in particular craniofacial region) until end of the 1st trimester; tissues and organs are formed in this period.
What happens during the fetal period?
Continued growth and development of already formed major structures until birth.
What is the blastocyst structure composed of?
- Embryoblast cells
- Trophoblasts cells
- Blastocele
What occurs in week 2 of development?
Embryo implantation into the endometrium with help of trophoblast cells.
What is gastrulation?
The process where the bilaminar embryonic disk becomes trilaminar, forming the three germ layers.
What are the derivatives of the three germ layers?
- Ectoderm: structures maintaining contact with the outer environment
- Endoderm: mucosa of the digestive tract (not oral part)
- Mesoderm: connective tissue, muscles, skeletal bones
What is the pharyngeal arch apparatus?
Begins to develop in the area of the future neck; forms significant structures of the head and neck.
What are the derivatives of Arch 1?
- Mandibular arch
- Masticatory muscles
- Trigeminal nerve
- Maxilla and mandible
What structures are included in Arch 2?
- Hyoid bone
- Mimetic muscles
- Pharyngeal nerve
- Facial nerve
What does ectoderm generally form?
- Oral mucosa epithelium
- Salivary gland epithelium
- Tooth enamel, dentin, cementum, pulp
- Skull bones, maxilla, mandible
What does endoderm develop into?
- Digestive tract mucosa epithelium (not oral part)
- Tongue and Pharynx
- Thyroid and parathyroid glands
What does mesoderm give rise to?
- Connective tissue
- Muscles of the head and body
- Skeletal bones
What is involved in facial development between weeks 4-8?
Enlargement and movement of 5 facial prominences.
What are the five facial prominences?
- Frontonsal prominence
- Paired maxillary prominences
- Paired mandibular prominences
What is the significance of the buccopharyngeal membrane?
Separates the foregut from the stomadeum and later breaks down allowing continuity.
What is the primary palate formed from?
Fusion of the 2 medial nasal prominences.
What is the secondary palate formed from?
Fusion of paired lateral palatine shelves.
When does the mandible, lower lip, and chin begin to form?
From fusion of the 2 mandibular prominences between 30 – 35 days.
When do enamel organs of primary teeth form?
In the gum pads in the 2nd month of pregnancy.
What is the developing organism known as after the 1st trimester?
Fetus.
