Orthodontics Lecture PDF

ORTHODONTICS 1 LECTURE Disproportion: retrognathic (class II), prognathic (class III) INTRODUCTION Unfavorable Sequelae of Malocclusion The term Orthodontics was first coined by Le...

ORTHODONTICS 1 LECTURE Disproportion: retrognathic (class II), prognathic (class III) INTRODUCTION Unfavorable Sequelae of Malocclusion The term Orthodontics was first coined by Le Felon in 1839 1. Poor facial appearance 2. Poor oral hygiene maintenance Orthodontics 3. Risk of dental caries 4. Risk of periodontal disease - Greek word orthos (right or correct) and odontos (tooth) 5. Abnormalities of function 6. Psychosocial problems Definition of Orthodontics according to: 7. Risk of trauma in the teeth Moyers — branch of dentistry that is mainly concerned with the study 8. TMJ Problems of growth of cranial facial complex and the development of the Abnormalities of function – cleft lip and palate problems (speech) occlusion and the treatment of the dentoalveolar abnormalities Noyes – study of the relation of the teeth to the development of the Aims of Orthodontic Treatment face and the correction and perburted development of the face - To obtain a result which go well with the patient’s personality Salzman – branch of science and art of dentistry which deals with the that make him or her look more esthetically appealing developmental and positional anomalies of the teeth as well as the jaw Jackson’s Triad American Board of Orthodontics (ABO) and American Association A. Functional Efficiency of Orthodontics (AAO) – supervision of the growth and development a. Mastication of the dentition and its related anatomical structures from birth to dental b. Phonation maturity B. Structural Balance - Combination of all the ideas a. Teeth b. Soft tissue c. Skeletal structures C. Esthetic Harmony a. Alignment of certain teeth b. Movement of complete dental arch including basal bone Types of Orthodontics Based on the nature and time of intervention a. Preventive Orthodontics What is Malocclusion? Action taken to preserve of what appears to be a normal occlusion at a specific time Guilford – distinguished two types of malocclusion b. Interceptive Orthodontics - Type I: Developing - Type II: Fully-developed Iniintercept ang mangyayaring malocclusion sa patient (art and science that employs to recognize and eliminate the potential malpositions in Malocclusion – anything beyond the accepted range of normal the facial and dental complex) occlusion (bad tooth) c. Corrective Orthodontics Common cause Fixed appliances (braces) Common characteristics of malocclusion Took place after the manifestation of a malocclusion Unfavorable sequelae – unfavorable causes Note: Common Characteristics of Malocclusion The best space maintainer for a child is their deciduous dentition 1. Overcrowded teeth 2. Spacing between the teeth 4 Types of Orthodontic Appliances, which can either be singly or 3. Improper bite between the maxillary and mandibular teeth combination to treat malocclusion: 4. Disproportion in the size and the alignment between the maxillary and mandibular jaws 1. Removable orthodontic appliances 2. Fixed orthodontic appliances Improper bite: deep bite, overbite, overjet, crossbite, open bite, edge- 3. Functional appliances (myofunctional appliances) to-edge 4. Orthopedic appliances/extraoral force appliances  a. Indications - Esthetic Dentistry b. Examples - Implantology Timing of Orthodontic Intervention – Related to the Stage of Tissue Systems of Human Dental Occlusion Dentition - Bone System - Deciduous - Muscle System - Early mixed - Nerve System - Late mixed/Early permanent - Tooth System - Late treatment HISTORY OF ORTHODONTICS Serial extraction – kesa magbraces ang patient, bubunutin nalang yung sungki na ngipin Contents - Introduction Advantages of Early Orthodontic Treatment - Evolution from Orthodontics Eliminate and reduce the abnormal swallowing and speech problems - Ancient Civilization - Middle Ages through Seventeenth Century Application of orthopedic appliances while still in growth period - 18th Century - 19th Century Scopes of Orthodontics - 20th Century - Appliances contributed by E.H. Angle - Monitoring and assessment of developing dentition - E.H. Angle’s Publications and Presentations - Correcting malocclusions of dental origin - Other Contributors - Correcting malocclusions of skeletal origin - Adult orthodontics Introduction - Guards - Management of dentofacial anomalies - Since the beginning of human history, human beings have understood at a very basic level that without a proper bite, Adult Orthodontics survival is very difficult - Started on the 19th century as a science 1. Adjunctive Orthodontic Procedures Evolution of the term orthodontics They refer to limited orthodontic treatment carried out to facilitate other dental procedures. Adjunctive procedures include uprighting of tilted - Regulations prior to 1900s abutment teeth prior to bridge work, space gaining for placement of - Orthodontia up to 1930s (that is referred to as a medical implants, etc. condition - Orthodontics up to 1970s, currently orthodontics and 2. Comprehensive Orthodontic Treatment dentofacial orthopedics It is usually carried out in young adults and involves full-fledged orthodontic treatment with or without extraction of teeth. Ortho – straightening of the teeth Benefits of Orthodontic Treatment - Improved confidence - Well-aligned teeth that are easier to keep clean and healthy - Ideally positioned teeth, which lessens the chance of gingivitis and advanced gum disease - Closed spaces to avoid the need for a bridge or denture - Better chewing and food digestion Correlation to Other Disciplines - General Anatomy - Oral Anatomy - Oral Histology Primitive Orthodontic Appliances – Greek and Etruscan artifacts, these - Oral Physiology societies used various kinds of metals and wires to strengthen their - Pediatric Dentistry teeth - Prosthodontics - Restorative Dentistry - Oral Surgery - Periodontics - Roentgenology - Nutrition  - Was the first to mention cast in Dentistry. - He used wax as an impression material 18th Century Pierre Fauchard - Father of Modern Dentistry - 1678-1761 - The one who really made the course dentistry as a science itself 1723 – developed the first orthodontic appliance They have discovered these with Egyptian mummies, crude metals Bandelette – plates used to straighten teeth by tying them to crude wrapped around in individual teeth metal plates with brass or silver wire. Catgut – used to close the gaps of the teeth, nylon-like John Hunter Ancient Civilization - English surgeon Hippocrates - 1728-1793 - Great teacher or anatomy, published a book (The Natural - Greek physician History of Human Teeth – 1771) - 460-377 B.C. o Growth, development, and articulation of both - The first to separate medicine from religion maxilla and mandible - Established a medical tradition, called the Corpus o The one to give the nomenclature incisors, Hippocraticum cuspids, bicuspids, and molars o Pre-christian era, has references from not only the teeth but also the jaws (descriptions of irregularity Philip Pfall and overcrowding) - Was the first one to report that Plaster of Paris can be used Aristotle as impression materials in 1756 - Greek philosopher Bunon - 384-322 B.C. - 1743 - First to write and study about the teeth in De Partibus - Was the first to use the term Orthopedics in connection to Animalium (On the Parts of the Animal) correction of malocclusion - He compared various dentitions of animals at the time 19th Century Aulius Cornelius Celcus Joseph Fox - Prominent roman author of the 1st Century - 25 B.C. to 50 A.D. - Wrote two books (1803-1806) in which he gave explicit - Described finger pressure (De Medicina – On Medicine) directions for the correction of malocclusion - A student of Hunter devoted 4 chapter of his book, The Gaius Pliny Secundus Natural History and Diseases of Human Teeth (1814) to that - Pliny the Elder topic. - A.D. 23-79 - He is interested in the judicious removal of deciduous teeth - Suggested filing for elongated teeth (to correct alignment) and the use of bite blocks to open the bite. - The remedies for tooth ache in natural history Joseph Sigmond Middle Ages Through the 17th Century - 1825 Pierre Dionis - He recognized habit as a factor in malocclusion - 1658-1718 William Imrie - Was the first to mention “separators for the teeth – to open - 1834 or widen the teeth when they are set too close together” - He was the first one to mention thumbsucking as a cause - Also commented on the etiology of dental irregularity. of dental abnormalities Matthacus Gottfried Purmana Friedrich Christoph Kneisel - 1692 - 1836  - Published the first book (German) on malocclusion of the - Published two volumes entitled “Treatise on Irregularities of teeth the Teeth and their Correction in 1888 and 1889. - Der Schiefstand der Zahne - Good at designing brace appliances and was the first to - Attempted the first classification of malocclusion and suggest the use of mild force at timed intervals to move teeth was the first to advocate the use of removable - First to recommend root or bodily movement of the tooth appliances - Introduced the modern impression tray William and Magill - First to use plaster model to record malocclusion - Developed molar bands on the teeth as early as 1871 Joachim Lefoulon Edward H. Angle - 1839-1841 - First one to coin the term Orthodontia originally - 1887 - Also the first to combine a labial arch with a lingual arch - He presented his classification of malocclusion JS Gunnell Henry A. Baker - 1840 - Introduction of the so-called Baker’s anchorage or the use - Introduced the chin strap as occipital anchorage for the of the intermaxillary elastics with rubber bands in 1893 treatment of mandibular protrusion, the principle of which is Angle – Father of Modern Orthodontics used even today. JMA Sehange of France 20th Century Edward Hartley Angle - He described a clamp band in which a screw was employed for tightening the band to the tooth. - 1855-1930 William Lintott - June 1, 1855 in Herrick, Pennsylvania - DDS, College of Dental Surgery in 1878 - 1841 - Joined the faculty of the Dental Department of the University - Introduced the use of screws in his work, On the Teeth of Minnesota in 1886 - Described premature loss of deciduous teeth as a cause - First professor of Orthodontics at Northwestern University of malocclusion School of Dentistry - Recommended that treatment begins between the age of 14 1892 – moved to Chicago and became a professor in Orthodontics and 25 years - bite-opening appliances Angle’s Contribution to Orthodontics Norman William Kingsley - Organized the first orthodontic society and called it as The Society of Orthodontics - 1829-1913 - Dentist, artist/sculptor, and orthodontist 1935 – The American Association of Orthodontists (AAO) - “Correction of cleft palate” - In 1866, he devised a technique called “Jumping the bite” American Association of Orthodontists with the use of a bite plane. - Used vulcanite on conjunction with ligatures, elastic bands - Established the magazine, a quarterly titled The American made of rubber, Jackscrews and the chin cap. Orthodontist, which we read today as the American Journal - In 1859, he presented the first obturator to a cleft palate of Orthodontics. patient. Appliances Contributed by Angle Emerson C. Angel “E” (expansion)-arch Appliance - 1823-1903 - In 1860, he was the first to advocate the opening of the median suture to provide space in the maxillary arch, since he strongly opposed extraction - Began the use of arch expansion in orthodontics Angel – first to introduce the expansion arch John Nutting Farrar - 1839-1913 - Father of American Orthodontics  Pin and Tube Appliance Ayaw magbunot – Emerson Angel Gusto magbunot – Calvin Case Charles A. Hawley - 1861-1929 - Used a celluloid sheet containing a geometric figure that 1900s – E-arch appliance when adapted to a model determined the extent of proposed tooth movement (1905) 1901 – pin and tube appliance - introduced the retainer appliance that bears his name 1910 – Ribbon arch appliance Hawley Retainer Ribbon Arch Appliance Ribbon arch – nakatayo, hindi pahiga. Tatalian ng ligature wires Martin Dewey Brackets (Edward Angle) - 1914 - Wrote Practical Orthodontics Edgewise Appliance - Founded the International Journal of Orthodontics, now known as The American Journal of Orthodontics and Orthopedics Raymond Begg - In the 1930s, he presented the Begg Appliance. o A modification of the ribbon arch appliance, but 1925 – edgewise appliance (Edward angle, brackets of today) used extremely light forces for treatment Edward H. Angle’s Publications and Presentations HD Kesling Published the first edition of his textbook, 1887 which would go through - 1945 seven editions under the following titles: - Introduced his philosophy of tooth movement by using a rubber tooth positioning device in which the teeth were 1. Irregularities of the Teeth (1887) moved into a more ideal cuspal relationship after major 2. A System of Appliances for Correcting Irregularities of the correction has been accomplished. Teeth (1890) 3. The Angle System of Regulating and Retention of the Teeth (1892) 4. The Angle System of Regulation and Retention of the Teeth – with an Addition of Treatment of Fractures of the Maxillae, (1895) 5. Angle System of Regulation and Retention of the Teeth and Treatment of Fractures of the Maxillae (1899) 6. Malocclusion of the Teeth and Fractures of the Maxillae (1900) 7. Treatment of Malocclusion of the Teeth (1907) Other Orthodontic Pioneers of the Early 20 th Century Calvin Case - In 1892, he stressed the importance of root movement and the first to use elastics for treatment. - Also a strong proponent of extraction theory in Orthodontics  GENERAL PRINCIPLES OF GROWTH AND DEVELOPMENT Appositional Growth Importance - Repeated division of cells - Periosteum, pericondrium - Understanding the principles and complexity of craniofacial growth is of paramount importance to orthodontists, since Interstitial Growth timely recognition and intervention of an abnormal jaw growth pattern by appropriate orthodontic appliances can - Grows as a whole and expands from within restore the normal occlusion and facial harmony using the - Very similar to accretionary growth active growth period. Meristematic Growth We have the study the growth spurts of each individual to know when - Growth from a tooth that contains a population of dividing is the right time to place braces to a patient. cells Difference between Growth and Development Compensatory Growth DEFINITION - There is a balance that is maintained through wear and tear Growth as defined by: - Ex. liver (major tissue loss if there is cirrhosis) Todd – increase in size PHASES OF GROWTH Krogman – there is a change in proportion and we progressively find Prenatal Growth out its complexity - Characterized by a rapid rise in cell numbers and fast growth Huxley – self-multiplication of a living substance rates. Moss – change in any morphological parameter which can be Postnatal Growth measured - It lasts for about the first 20 years of life and is characterized Moyers – quantitative aspect of biologic development per unit of time by declining growth rates and increasing the maturation of tissues. Meridith – very detailed, entire series of sequential anatomic and physiologic changes from prenatal life to senility Maturity Development as defined by: - A period of stability during which body achieves maximum function and growth processes are limited to the Todd – progress towards maturity maintenance of an equilibrium state between cellular loss Moyers – all the naturally occurring unidirectional changes in the life of and gain. an individual from its existence from a single cell to elaboration as a Old Age multifunctional unit terminating in death Types of Growth - Is a period during which functional activity declines and growth processes slow down. 1. Growth at Cellular Level a. Cellular Hyperplasia – a phenomenon by which Factors affecting Growth and Maturation protein and DNA synthesis leads to an increase in 1. Genetic Factors cell number by mitotic division. 2. Growth Hormones and Growth Factors b. Cellular Hypertrophy – is a synthesis of protein 3. Nutrition and cellular material without mitotic division that 4. Illness leads to an increase in cell size. 5. Race 6. Season and Circadian Rhythm Embryogenesis/organogenesis – examples of hyperplasia 7. Adult Physique 2. Growth at Tissue Level 8. Socioeconomic Factors a. Accretionary Growth 9. Exercise b. Appositional Growth 10. Family Size and Birth Order c. Interstitial Growth 11. Secular Trends d. Meristematic Growth 12. Psychological Disturbance e. Compensatory Growth Genetic Factors Accretionary Growth - The genes have the basic control of growth. - Increase in the amount of extracellular matrix (outside of the Growth Hormones and Growth Factors cell, provides support – cytoskeleton)  - In particular, postnatal growth is affected by the circulating - May be useful for the development of motor skills, for concentration of growth hormone somatotropin and increase in muscle mass, for fitness, and general well-being. somastatin. - Abnormal secretion of growth hormone after the epiphysis Family Size and Birth Order plates have fused results in acromegaly - First born children tend to weigh less at birth and ultimately Other growth factors affecting growth are: achieve less stature and a higher IQ. - Insulin-like Growth Factor: I and II Secular Trends - Platelet-derived Growth Factor - Epidermal Growth Factor - 15-year old boys are approximately 5 inches taller than 15- - Vascular Endothelial Growth Factor year old boys were 50 years ago - Transforming Growth Factor-B Psychological Disturbance Hormones of thyroid gland – stimulates metabolism, important for - It has been shown that children experiencing stressful growth of bones, teeth, and brain conditions display an inhibition of growth hormone. Nutrition Methods of Studying Physical Growth - Poor nutrition at critical stages of life may permanently alter Measurement Approach the normal development pattern of many organs and tissues. - Proper nutrition is essential for normal postnatal growth. - Includes techniques that measures certain criteria on living animals/skeletal remains. These are not invasive. Growth process accelerates when deficient nutrient is replaced during o Craniometry – measurement of human skull growth period, i.e. the Catching-up Growth. o Anthropometry – technique in which a skeletal dimension can be measured on a living individual Osteoclast – destruction o Cephalometric Radiography – study of growth and development before we assume the treatment Osteoblast – construction of bone cells to a patient particularly in ortho Vitamin c – for proper bone and tissue growth Experimental Approach Vitamin D - This approach includes techniques that may be manipulative and invasive in nature and thus may harm the animal. Such Illness studies are carried out on experimental animals. - Systemic disease has an effect on child growth. Experimental methods of study growth include: o Vital Staining Example of systemic disease – asthma o Radioisotopes o Autoradiography Race o Implant radiography - Some so-called racial differences are clearly due to climatic, Modes of Collection of Growth Data nutritional, or socioeconomic differences. Cross-sectional Studies Season and Circadian Rhythm - A large number of individuals of different age groups are examined at one occasion to develop information on growth - Growth in height is faster in spring than in autumn, while attained at a particular age. weight increase occurs faster in autumn than in spring Longitudinal Studies Adult Physique - Involve repeated examination and measurements of same - There are correlations between the adult physique and subjects at regular intervals over a long period during active earlier development events. growth. Tall women tend to mature later Mixed/Semi-longitudinal Studies Socioeconomic Factors - Combinations of the cross-sectional and longitudinal type of studies to obtain the advantages of both methods of data - Children living in favorable socioeconomic conditions tend to collection. be larger, display different types of growth. Scammon’s Growth Curve Exercise Richard Scammon described four basic growth curves of the tissues of the body: 1. Lymphoid 2. Neural 3. General 4. Genital Prenatal Growth and Development of Head, Face, and Oral Cavity What results in this period? Prenatal – how the baby was conceived, how was the face developed 1. An increase in size by contributing the different parts including its embryology 2. A change in proportion between the various structures also occur Once the baby is delivered, it becomes post-natal At the 10th week (3rd month) of pregnancy, it is not considered as an Pre-Natal Period of Development embryo but rather a fetus Pre-natal is a dynamic phase in the development of a human being. At the end of the 12th week, they can be assigned a sex (through ultrasound) Three Phases of Development: The height increases 5000 times as compared to a 3 fold increase 1. Period of the Ovum during the post natal period Fertilization to 2 weeks to 14th day The human somatic cell contains 46 chromosomes, called as the diploid number When does this period extend? The sex chromosomes in females are XX and in males are XY. This period extends from the time of fertilization. The cleavage of the ovum and the attachment (implantation) of the ovum to the intrauterine There are two series of division of somatic cells, mitosis and meiosis wall and the rapid proliferation of the cells occurs with no or little differentiation Out of 44 autosomes, the remaining two are the sex chromosomes and these are designated as X and Y 2. Period of the Embryo Mitosis Occurs from the third week to the eighth week (56th day) - Produces the same number if chromosomes in the resulting - Very critical daughter cell When does this period extend? Meiosis th th - This period extends from the 114 to 56 day of the - Produces half the number (i.e. 23 designated as haploid, intrauterine line (IUL) – nasa loob pa ng sinapupunan with resultant formation of gametes Why is this stage of intrauterine life vulnerable to exposure of Development begins with fertilization, the process in which the male teratogens? gamete (sperm) and the female gamete (oocyte) unite to form a zygote. - Teratogens are viruses that can cause birth defects - This period is where the many recognizable genital defects Early Embryonic Events will be evident - How fertilization occurs Zygote – fertilized egg, start of the fusion of the sperm and egg cell (single cell stage) Fertilization and Morula Formation Is a zygote an embryo? No, since it is only in the early stages of Fertilization development - Process by which male and female gametes fuse, occurs in Embryo – second stage after zygote, the later stage of development the ampullae of the uterine tube where the fertilized egg that begins once the zygote undergoes several rounds of cell division undergoes a series of rapid divisions to form a ball of cell (Morula) What occurs during this period? Zona pellucida – external surface of the egg cell - A major part of development of the facial and cranial organs will be differentiated (organogenesis) The Process of Fertilization 3. Period of the Fetus The male gamete (sperm) fuses with the female gamete (ovum) Occurs from the 56th day up to birth Blastocyst Formation and its Implantation When does this period extend? - Fluid seeps into the morula and its cells realign to form a This phase extends from 56th day in the IUL fluid filled hollow ball (blastocyst) - 2 cell population: The development is largely in the form of growth and maturation rather o Trophoblast cell than differentiation o Inner cell mass/Embryoblast cell Growth and Maturation Period Fluid filled cavity – primitive yolk sac - The nervous system develops as a thickening within the ectodermal layer at the crest of the embryo called the Neural Proper embryo – small cluster within the cavity Plate - Cells of the neural plate comprise the Neuroectoderm Bilaminar Discs: A depressed groove forms between the neural folds in the midline - Epiblast called Neural Groove o Dorsally situated columnar cell layer - Hypoblast o Cuboidal cell layer on the ventral aspect Bilaminar disc forms during the second week of development Trilaminar Disc Forms during the third week through gastrulation The neural folds approach each other and fuse to form the “neural This disc establishes three dimensional organizations tube” which then gets separated from the surface of the ectoderm. Lays down the formation for the tissues and organs of the body Marks the major body access 3rd week of Gastrulation - The bilaminar embryo is converted into trilaminar embryo Begins with the formation of primitive streak (develops in the midline of epiblast towards the caudal end) Primitive node The Neural Crest Cells - A small depression located near the narrow groove with bulging areas on each side - As the neural tube is forming, a population of cells develop along the lateral margins of the neural plate. Some cells of the epiblast migrate and invaginate the primitive streak - These cells are the neural crest cells and migrate throughout and primitive node the body and differentiate to various structures Some of these cells displace the hypoblast layer to form the embryonic - Neural crest cells in the head region provide embryonic endoderm connective tissue (the ectomesenchyme) which is essential for craniofacial development. Some remain in the endoblast and the epiblast (embryonic mesoderm) all the tissues of the tooth and its supporting structures except enamel Remaining cells in the epiblast – ectoderm are derived from ectomesenchymal cells. All 3 embryonic germ layers are formed from the epiblast layer Proper migration of neural crest cells is essential for the development of face and teeth Primitive streak – elongated band of cells that forms along the axis of the developing fertilized egg that was formed early during gastrulation Failure of neural crest cells to properly migrate to the facial region and is considered as the forerunner of the neural tube and the nervous leads to craniofacial anomalies (Treacher Collins Syndrome) system - Other names: 3 to 4 weeks of Organogenesis o Mandibulofacial Dysostosis o Franceschetti-Zwalen-Klein Syndrome - Major tissues and organ differentiate from the trilaminar embryo - Head, face, and tissues contributing to the tooth development - Nervous system and neural crest tissue differentiates from ectoderm and the folding of the embryo occurs in two planes: o Along head and tail o Lateral axes Neurulation Pierre Robin Sequence  The Branchial Arches Pharyngeal pouch – can be found on the endoderm - Pharyngeal Arches Pharyngeal groove – ectoderm Introduction 4 Important Processes The human face is first characterized by an invagination or dimple in Maxillary Process the surface ectoderm layer appearing just below the forebrain. Frontonasal Process Mandibular Process Lateral Nasal Process DEVELOPMENT OF THE PERIORAL REGION Introduction - The face at the 5th week is about as thick as the sheet of paper (bond paper) and the whole face is only about 1 and ½ Buccopharyngeal membrane will disintegrate and there will be a mm wide continuity from the outside environment to the inside The branchial arches give rise to the lower face, neck, and part of the upper thorax, while the frontonasal prominence gives rise to the forehead and nose. Failure of the branchial arches to correctly develop results into an anatomical and developmental defects that will be manifested in different ways The Branchial Arches - Embryologic structures that develop into anatomic structures in the adult human. - The term branchial derives from the Latin word branchia, meaning gills, and is used to describe the development of many species of fish and amphibia. Therefore, the term branchial arches is alternatively named pharyngeal arches to more accruately describe the human anatomy. Hyoid arches – 2nd brachial arch Base of the tongue – 3rd branchial arch, paired bars of the mesoderm that is divided by the heart 4th arch is similar to the 3rd and 5th branchial arches The Branchial Arches and the Heart A – at 4 weeks, future face which is indicative of the bulging of the forebrain, below is the first branchial arch (mandible) At 5 weeks, the face appears crowded between the forebrain and the heart, which occupies much of the chest cavity at this stage, and the B – six weeks, the oral slit is noted with the nasal pits, eyes appear on lungs are not quite functioning well yet and begin to form in the fourth the side of the head and the mandibular arch bounds the oral seed month. below C – six and a half weeks, eyes are near at the front of the face, nose is The growth of the heart – affects the development of face almost defined, the developing ears appear at the corners of the mouth Because the face, during its early period of rapid growth and D – 8 weeks, face is fused together, forebrain begins to grow forward organization, is crowded between enlarging forebrain and the pulsating leaving the ears behind heart. The hyoid arch, frontonasal process, and maxillary process form the Pharyngeal Groove facial groove - The first pharyngeal groove produces the external auditory meatus (ear canal) The growth on the lateral remains constant and causes the nose to appear smaller The maxillary process and median nasal process fuse to form the upper lip In the 6th week, the upper face and mandibular arch appears flat and broad. In the upper face, the nasal pit is positioned on the lateral corners of the face Midline grooves disappear with small oval tissues that appear just below the lateral aspect of the mouth Primary Palate – mass of tissue that is bounded in the oral cavity below and above the nostrils Since the tissue underlying each nostril represents the first separation of the nasal pit from the oral cavity, therefore it represents the primary palate Failure in any of the steps in development may result to a cleft lip blind pockets that are connected to the oral cavity Hare lip – very rare compared to cleft lip and nostrils The covering of the maxillary nasal process and median nasal process PRENATAL GROWTH AND DEVELOPMENT OF HEAD, FACE, AND from this epithelial sheath will later on fuse together and will be seen ORAL CAVITY on the right side Development of Palate The posterior aspect of the pit opens into the roof of the mouth - When does the development of the palate occur The lip is unified anteriorly, and separation of the floor of the pits in the form of a cleft is prevented the palate develops between the 6th and 9th week of gestation DEVELOPMENT OF THE UPPER LIP - Primary - Secondary Maxillary process with median nasal process will form the floor (base) of the nostrils Primary Palate - UPPER LIP DAW PALA - Triangular-shaped part of the palate anterior to the incisive foramen The lateral nasal process will enlarge to form the side of the nose - Developed from the frontonasal process The slit below the nostril is the nasal fin which is the potential site of a - Forms the premaxilla, which carries the incisor teeth cleft lip Deeper part of the intermaxillary segment of the maxilla Represents the only small part of the adult hard palate The internal merging with the median nasal process From what histological part is the primary palate? Maxillary Process Secondary Palate - Will give rise to hard and soft palate - Posterior to the incisive foramen - 2 palatine shelves which extend from right and left to midline Nasal Septum - Cartilage and bone of the nose - This divides the nasal cavity (left and right) - When off centered, it is called a deviated nasal septum Palatine shelves are covered by an epithelial lining which - Two bulges arise adjacent to the tuberculum impar called becomes/degenerates and the connective tissue of the palate lingual swellings intermingles w one another - All these structures form as a result of proliferation of the 1st arch mesenchyme Cleft Lip and Cleft Palate Introduction - Occurs when mesenchymal connective tissues from different embryologic structures fail to meet and merge with each - The tongue musculature originates from the occipital other. myotomes at the beginning of the 4th week - Commonly known as the orofacial defects - Results as a failure fusion of the median nasal and maxillary processes - May extend up to the alveolar process The body of the tongue arises from the first branchial arch - Happens when a tissue which makes up of the lip does not fuse before birth Base – 2nd, 3rd, and 4th branchial arch - Can be enlarged from the lip to the nose - Can be one or two sides (rare) Cleft Palate Dalawang lateral lingual swelling + tuberculum impar = body of the tongue (three primordial) - Ventromedial aspect - Failure of the nasal septum and the primary palate - Other term for cleft hard palate:uranos chisis - Cleft soft palate: staphylos chisis DEVELOPMENT OF THE TONGUE - The tongue begins to develop at about 4th week of gestation in the floor of the primitive pharynx. - Begins as a midline enlargement in the floor of primitive pharynx called the tuberculum impar  4 paired intrinsic muscles of the tongue 1. Superior Longitudinal 2. Inferior longitudinal 3. Verticalis 4. Transversus Origin: inside of the tongue Function: changing the shape of the tongue Sulcus Terminalis – site of the union between the base of the tongue and usually they are delineated by a v-shaped groove U shaped sulcus will develop in front and on both sides of the oral Terminologies Related to Growth (base of the tongue) which allows it to be free and mobile except at the regions of the lingual frenum Growth Fields Copula - Periosteal (outer) and endosteal (inner) surface of bones are blanketed by soft tissues and cartilage or osteogenic - Below the tuberculum impar (foramen cecum) membrane. - Below the foramen cecum is the hypobranchial eminence - With this blanket of soft tissue matrix, the growth fields are (copula) disturbed in a characteristic mosaic like pattern across the - The base of the tongue is indicated by the median elevation surface of a given bone. - Between the copula and the tuberculum impar is a small pit called the foramen cecum (will give rise to a thyroid gland Growth fields either have depository or resorptic activity. If the tissue) periosteal growth field is resorptive, the opposing endosteal field is depository and vice versa. Development at 6th and 7th week Growth Sites The lateral lingual swelling will enlarge. There will be overgrowth, but the tuberculum impar will reduce in size and the furrow appears along - Certain areas of a bone where significant growth of that bone the lateral borders of the tongue separating it from the developing takes place alveolar ridges - Growth sites show marked response to external influences. At 81/2 to 9 weeks, the body of the tongue appears clearly Unlike centers, growth sites do not control the overall growth of the differentiated bone. They are simply areas of the bone where exaggerated growth takes place. Tongue is innervated by the hypoglossal nerve Growth sites can occur at growth centers, but all growth sites are Most posterior part of the tongue – median palatal swelling arising from not growth centers. the 4th pharyngeal arch Difference of Bone and Cartilage Receives its innervation from the superior laryngeal nerve Cartilage – thin, avascular, flexible, and resistant to compressive forces Sensory innervation of the body of the tongue is from the nerve of the first arch called the trigeminal nerve Bone – highly vascularized, and its calcified matrix makes it very strong. Motor supply of the tongue is supplied by the hypoglossal nerve Extrinsic Muscles of the Tongue and Innervations - Styloglossus - Hypoglossus - Genioglossus - Palatoglossus Originates from the structures adjacent to the tongue Elevation, depression, retraction, protrusion Derived from the myoblast which originates from the occipital myotomes (occipital somites) They receive their innervation from the hypoglossal nerve except from the palatoglossus muscle which is supplied by the vagus nerve