Growth and Development of Craniofacial Complex PDF

ORTHDONTICS Growth and Development of Craniofacial Complex GROUP 2  Members Balasan, Aishley Jade Barabona, Je - An Cuatriz, Clyde Bata, Julian Miguel Dalisay, Jenny Baticos, Yuhanna Jane De La...

ORTHDONTICS Growth and Development of Craniofacial Complex GROUP 2  Members Balasan, Aishley Jade Barabona, Je - An Cuatriz, Clyde Bata, Julian Miguel Dalisay, Jenny Baticos, Yuhanna Jane De La Llana, Gabrielle Bordones, Shane Kate Demegilio, Dustin Cabacaba, Claire Dioman, Armstrong Castillano, Bea Castor, Shen Mae 2  TABLE OF CONTENTS A. Importance B. Difference between growth and development C. Prenatal growth and development Brachial Arches Development of perioral region Development of the tongue Development of palate 3  TABLE OF CONTENTS D. Growth of Craniofacial Skeleton Osteogenesis Difference between cartilage and bone Mechanisms of bone growth Deposition and resorption Enlow's "V" principle Remodeling Growth movements Drift Displacement 4  TABLE OF CONTENTS E. Theories of Cranialfacial Growth Genetics Sicher Scott Moss Petrovic F. Controlling Factors of Craniofacial Growth G. Postnatal Development of Craniofacial Complex Cranial case Cranial base Nasomaxillary complex Mandible 5  TABLE OF CONTENTS H. Dynamics of Facial Growth Differential growth Clinical implications 6 Today, you’ll be able to: Understand how the bones and structures of the face and skull grow and develop, The craniofacial complex is and why this is important home to the muscles for treating issues like responsible for facial expressions. It takes about crooked teeth and facial 17 muscles to smile but 43 to problems. frown—so smiling is easier on your face! 7 Definition of Terms Intrauterine Life Intrauterine life refers to the period of development a baby undergoes while inside the uterus, from conception until birth. It begins with fertilization, followed by the formation of the embryo and later the fetus. Craniofacial Pertaining to the head (skull) and face. Pathologic refers to something that is related to or caused by disease or abnormal conditions. It’s often used in medical contexts to describe changes or conditions that are unhealthy or abnormal. 8 Definition of Terms Malocclusion is a term used to describe when your teeth don’t line up properly when you bite down. It’s often referred to as a "bad bite." This can happen when your upper and lower teeth don’t meet in a straight, even way, 9 Definition of Terms Cohabitational Effect Generally refers to the influence that living together or cohabiting (usually in a romantic or familial context) has on individuals. In genetics or developmental biology, it could refer to how environmental or social factors, like shared living conditions or interactions, might affect physical traits, behavior, or development. Progeny Refers to the offspring or descendants of an individual, typically in the context of reproduction. It can refer to children, young, or future generations that are the result of reproduction 10 Definition of Terms Discontinuous Distribution It means that traits are divided into separate, distinct categories with no in- between values. The trait doesn’t gradually change but falls into clear, separate groups. Continuous Distribution It means that a trait can have many different values that gradually change, without clear boundaries between them. The trait changes smoothly across a spectrum. 11 Definition of Terms Mendelian Inheritance Refers to how traits are passed down from parents to children through specific genes. It was discovered by a scientist named Gregor Mendel. He found that traits, like eye color or seed shape, follow certain patterns and are controlled by one gene from each parent. These genes can be dominant or recessive, which determines how the traits are expressed in the child.. Polygenic Refers to traits or characteristics that are controlled by multiple genes, rather than a single gene. These traits are influenced by the combined effects of several genes, each contributing a small amount to the overall trait 12  Orthodontics A dental speciality focused on aligning your bite and straightening your teeth. ➔ The variation in craniofacial morphology which is the primary source of serious malocclusion. It is important to distinguish normal variation from the effects of abnormal or pathologic processes. How the face changes from its embryologic form through childhood, adolescence and adulthood. 13  Why the Growth of the Face and Skull is Important The growth of the face and skull (craniofacial complex) is really important for how we look, eat, speak, and even breathe. This process involves all the bones, muscles, and soft tissues of the head working together as we grow. Here’s why it matters: It Helps Us Do Everyday Things It’s Key for Treating Problems It Affects How We Look Catching Problems Early It’s Linked to Healthy Teeth 14 growth vs development 15  Definitions Growth Development Is a normal changes in amount of living Growth is often synonymous with substance development. May results in increase or decrease in Biologically development is a process of size, change in form or proportion, continuous changes occurring in a complexity and texture. predetermined direction. Growth changes in quantity 16  DEFINITIONS RELATED TO GROWTH J.S HUXLEY “ The self multiplication of living substances” “Increase in size, changes in proportion and progressive KROGMAN complexity” TODD “An Increase in size” “Entire series of sequential anatomic and physiologic changes MERIDITH taking place from the beginning of prenatal life to senility” MOYERS “Quantitative aspect of biologic development per unit of time” MOSS “Change in any morphological parameter which is measurable” PROFIT “Growth refers to an increase in size/number” 17  DEFINITIONS RELATED TO DEVELOPMENT TODD “Development is progress towards maturity” PROFIT “Development is in complexity” “Development refers to all the naturally occurring unidirectional changes in the life of an individual from MOYERS its existence as a single cell to its elaboration as a multifunctional unit terminating in death” 18  At 3rd month of intra uterine life: PATTERN Head: 50% of total body length At birth: OF Head: 39% of total body length Legs: 30% of total body length GROWTH Adults: Head: 12% of total body length Legs: 50% of total body length 19 GROWTH AND DEVELOPMENT Differentiation Is the change from generalized cells or tissues to more specialized kinds during development Is change in quality or kind Translocation Change in position Most of the growth is taking place at the condyle and ramus while the entire mandible is translocated ventrally Maturation Used to express the qualitative changes which occur with ripening 20 or aging PRENATAL GROWTH AND DEVELOPMENT 21 BRANCHIAL ARCHES 22 INTRODUCTION TO PRENATAL GROWTH Prenatal facial development occurs AND BRANCHIAL ARCHES early, between weeks 5–7. Week 4: The future face and neck region begin segmenting. Five branchial arches form, which contribute to: Face and neck systems: Skeletal, muscular, vascular, connective tissues. Primary contributors: 1st and 2nd arches (mandibular and hyoid). 23  Week 4: Facial development starts with a dimple under the forebrain. This pit outlines the oral cavity and connects with the foregut. FORMATION OF FACIAL 24 FEATURES  Week 5: Face “crowded” between forebrain and enlarging heart. Oxygen supplied by placenta; heart pumps blood early. FORMATION OF FACIAL 25 FEATURES Key Milestones in Facial Development Week 4–8 Progression: Week 4: Forebrain bulges, 1st branchial arch appears. 26 Key Milestones in Facial Development Week 4–8 Progression: Week 6: Nasal pits and oral slit form; eyes on the sides. 27 Key Milestones in Facial Development Week 4–8 Progression: Week 6.5: Eyes move forward, nose and ears appear. 28 Key Milestones in Facial Development Week 4–8 Progression: Week 8: Face masses fuse, forebrain shifts forward, ears move back. 29 ORTHODONTICS DEVELOPMENT of PERIORAL REGION 30  DEVELOPMENT OF PERIORAL REGION Nasolabial Oral PERIORAL - peri = "around" Folds Commissures - oral = "mouth" PERIORAL REGION - refers to the area of the face surrounding the mouth. - is bounded superiorly by the nasolabial folds, laterally by the oral commissures, and inferiorly by the mentolabial sulcus. Mentolabial Sulcus 31 DEVELOPMENT OF PERIORAL REGION 5 weeks 6 weeks 8 weeks 10 weeks 32  DEVELOPMENT OF PERIORAL REGION 5th week As thick as the paper 1 1/2 mm wide Oral pit is bounded above by the frontal area Below by the mandibular arch. Appears shovel shaped 33  DEVELOPMENT OF PERIORAL REGION 6th week Midline groove is apparent Two small, oval, raised areas appear above the lateral aspects of the future mouth. In the next 48 hours, the centers of these raised areas become depression. Tissues around them continue to grow anteriorly. 34  DEVELOPMENT OF PERIORAL REGION 8th week Depressions deepen into pits Becomes the future nostrils and the masses surrounding them. Tissue between the nasal pits is termed medial nasal process. Those lateral to the pits are called lateral nasal processes. Tissues are originate from the superficial epithelial and connective tissues of the 35 frontal area.  DEVELOPMENT OF PERIORAL REGION 10th week Fusion taking place between the median nasal process and lateral nasal processes. Nasal pits undergo further elongation. The raised anterior edges of these pits from the shape of minute horseshoes. 36  DEVELOPMENT OF PERIORAL REGION 10th week Fusion taking place between the median nasal process and lateral nasal processes. Nasal pits undergo further elongation. The raised anterior edges of these pits from the shape of minute horseshoes. 37  DEVELOPMENT OF PERIORAL REGION 10th week Fusion taking place between the median nasal process and lateral nasal processes. Nasal pits undergo further elongation. The raised anterior edges of these pits from the shape of minute horseshoes. 38  DEVELOPMENT OF PERIORAL REGION 10th week The inferior ends of the horseshoes come into contact with each other. Distance between two nasal pits does not increase during this important period of facial development. Pits themselves increase in both height and length. 39 DEVELOPMENT OF PERIORAL REGION The primary palate is the tissue underlying each nostril, representing the first separation of the nasal cavity from the oral cavity. Its formation is crucial as failure in any step may result in a cleft lip. The process involves contact between the medial border of the maxillary process and the lateral border of the medial nasal process, forming a lamina called the "nasal fin." 40 DEVELOPMENT OF PERIORAL REGION Lip development is a three-stage process, the first being contact of the two epithelial sheets covering the adjacent processes; the second, fusion of the epithelium into a single sheet; and, finally, degeneration of this sheet, followed by invasion by connective tissue of the lip growing through it. The developing eyelids are an example of two epithelial laminae that come into tight contact but do not fuse or undergo connective tissue pene- tration. They simply remain closed, with their surfaces fused, until the seventh prenatal month, at which time they open, exposing the eyes. 41  NG ORTHODONTICS GROUP 2 GROWTH AND DEVELOPMENT OF CRANIOFACIAL COMPLEX TO UE “dil a” of the t n p me l o e Dev 42 DEVELOPMENT OF TONGUE Largest singular muscular organ inside the oral cavity. The tongue is a muscular structure as well as a sensory organ that starts developing alongside the external face around week four of intrauterine life. 43 DEVELOPMENT OF TONGUE The two parts develop separately which results in them having different nerve supplies. POSTERIOR 2/3 TERMINAL SULCUS ANTERIOR 2/3 44 DEVELOPMENT OF TONGUE Around week four of embryonic development as a result of the folding of the embryo along the rostrocaudal axis and the lateral axis the neural tube expands greatly forming the primitive forebrain which produces a bulge known as the frontal prominence lateral to the neural tube is the paraxial mesoderm 45 DEVELOPMENT OF TONGUE which partially segments rostrally to form somitomeres and fully segments caudally to form somites 46 DEVELOPMENT OF TONGUE A small pit called the stomodeum forms between the frontal prominence and the developing cardiac bulge and it will eventually become the oral cavity 47 DEVELOPMENT OF TONGUE At the same time, six little bulges or thickenings of the mesoderm sprout from the primitive pharynx to become the branchial or Pharyngeal Arches These arches are paired symmetrical bumps that form on each side of the lateral aspect of the embryo in a craniocaudal fashion going from head to tail. 48 DEVELOPMENT OF TONGUE The neural crest cells from the midbrain and the first two rhombomeres migrate bilaterally to the region and infiltrate the mesoderm bumps where they support the development of embryonic connective tissue needed for craniofacial development called ecto mesenchyme 49 DEVELOPMENT OF TONGUE the pharyngeal arches are separated externally by small clefts on the pharyngeal wall called branchial grooves and internally by corresponding depressions called pharyngeal pouches 50 DEVELOPMENT OF TONGUE the first pharyngeal arch splits up into two processes the upper maxillary process and the lower mandibular process the pharyngeal arches on either side then proceed to grow towards the midline and merge with their counterparts beneath the stomodeum now the tongue begins to develop around week four of intrauterine life 51 DEVELOPMENT OF TONGUE the anterior two-thirds develops from the first pharyngeal arch and the posterior one- third develops from the second third and fourth pharyngeal arches 52 DEVELOPMENT OF TONGUE The anterior 2/3rd starts developing when the mesoderm of the first pharyngeal arch proliferates giving rise to a midline swelling called the tuberculum impar. During the sixth and seventh week, the mesoderm of the same arch gives rise to two more bulges on the right and left. 53 DEVELOPMENT OF TONGUE During the 6th and 7th week the mesoderm of the same arch gives rise to two more bulges on the right and left lateral lingual swellings just lateral and above the tuberculum impar the lateral lingual swellings enlarge overlap the tuberculum impar and merge with each other along the midline. 54 DEVELOPMENT OF TONGUE giving rise to the mucosa over the anterior 2/3rd of the tongue since the mucosa overlying this area of the tongue has its origin from the first pharyngeal arch 55 DEVELOPMENT OF TONGUE it receives its sensory innervation from the lingual branch of the mandibular division of the fifth cranial nerve 56 DEVELOPMENT OF TONGUE the two lateral lingual swellings merge develops into a fibrous septum which appears as the midline groove over the surface of the tongue known as the median sulcus DEVELOPMENT OF TONGUE Similarly, the posterior 1/3rd of the tongue also begins to develop as two mesodermal swellings the first swelling known as the copula develops in the midline of the second and third pharyngeal arches. During week four the second swelling known as hypobranchial eminence grows from the midline of the third and fourth pharyngeal arches DEVELOPMENT OF TONGUE In the following weeks, around week five, the hypobranchial eminence begins to grow upwards, and along the way, it grows over the copula. The hypobranchial eminence then goes on to become the mucosa over the posterior third of the tongue, which grows upwards and fuses with the anterior portion, forming the complete Tongue. DEVELOPMENT OF TONGUE The mucosa overlying this area of the tongue receives its sensory innervation from the ninth cranial nerve, the glossopharyngeal nerve the region between anterior 2/3 and posterior 1/3 contains a v-shaped depression called the terminal sulcus. at the tip of the terminal sulcus the endoderm descends downwards and develops into the thyroid gland the descent of the endoderm creates a tiny sac-like structure called foramen cecum DEVELOPMENT OF TONGUE As the lingual swellings are developing, the occipital somites that come from the paraxial mesoderm migrate into the developing tongue. The occipital somites give rise to myoblasts which go on to develop into the tongue skeletal muscles. The Motor Innervation of the tongue muscle comes from the 12th cranial nerve, the hypoglossal nerve. 61 DEVELOPMENT OF TONGUE The Taste Buds start to sprout over the surface of the Tongue around week 8 DEVELOPMENT OF TONGUE As the body of the tongue appears as a more unified structure. The tongue grows so rapidly that it pushes into the nasal cavity above and between the two palatine shelves. And by 8½ or 9 weeks the muscles of the body of the tongue appear clearly differentiated. Thus, the oral and nasal cavities originate from the single stomodeal cavity and become separated as the palatal shelves elevate and grow between them. DEVELOPMENT OF TONGUE The Taste Buds start to sprout over the surface of the Tongue around week 8 and finish differentiating into the different types around week 11 to week 13. DEVELOPMENT OF TONGUE 1. Fungiform Papillae: Sweet 3. Foliate Papillae: Sour 2. Circumvallate Papillae: Bitter and Umami 4. Filiform Papillae: No taste (texture only) DEVELOPMENT OF PALATE 67  DEVELOPMENT OF PALATE The palate is the tissue that interposes between the oral & nasal cavities it develops from two parts 1. The Primary Palate 2. The Secondary Palate The Primary Palate -Fusion of the two medial process with the fronto nasal process results in the formation of primary palate The Secondary Palate -The formation of secondary palate commences between 7 and 8 weeks and completes around the 3rd month of the gestation. 68 DEVELOPMENT OF PALATE The Secondary Palate -Three outgrowth appear in the oral cavity 1. The two palatal process 2. The nasal septum Hard Palate and Soft Palates Hard palate At a later stage, the mesoderm in the palate undergoes intramembranous ossification to form the hard palate. Intra-membranous: Conversion of mesenchymal connective issue, usually in membranous sheaths, directly into osseous USSHE IS known as intramembranous ossification Soft palate However ossification does not extend in to the most posterior portion, which remains as the soft palate 69 DEVELOPMENT OF PALATE 70 DEVELOPMENT OF PALATE 71 ORTHODONTICS GROWTH AND DEVELOPMENT OF CRANIOFACIAL COMPLEX f the cran o io th fa Gro w cial skele ton 72 GROUP 2 Why is the growth of the craniofacial skeleton crucial in orthodontics? Variations in craniofacial morphology are the source of the most serious malocclusions and clinical changes of bone growth and morphology are a fundamental basis of orthodontic treatment 73 Osteogenesis ➔ also known as ossification ➔ process of bone formation ➔ bones forms in two basic modes named after the site of appearance (cartilage or membranous connective tissue) ➔ transformation of a preexisting mesenchymal tissue into bone tissue ➔ bones of the face and skull develop and remodel. Allows the expansion of the craniofacial skeleton to accommodate brain growth and facial development. 74  Osteogenesis TWO MAIN TYPES Endochondral Bone Formation - Bone forms by replacing a pre-existing cartilage model. This is how most facial bones (mandible, maxilla, sphenoid) develop Intramembranous Bone Formation - Bone develops directly from mesenchymal tissue. This is how flat bones of the skull (frontal, parietal) are formed 75  The ENDOCHONDRAL BONE FORMATION I. ROLE Primarily responsible for the growth of the base of the skull (e.g., sphenoid, ethmoid, temporal bones). II. PROCESS Begins with the ORIGINAL MESENCHYMAL TISSUE BECOMES CARTILAGE. Cartilage is gradually replaced by bone tissue. Crucial for the vertical and posterior growth of the craniofacial skeleton. 76  THE ENDOCHONDRAL BONE IS NOT FORMED DIRECTLY FROM CARTILAGE! The cartilage provides a framework for the subsequent deposition of bone tissue. It's like a mold that is eventually filled and replaced by bone. 77 The Intramembranous Bone Formation I. ROLE the process of bone formation from connective tissue membranes II. PROCESS Mesenchymal cells differentiate Osteoblasts secrete osteoid Osteoid calcifies Osteoblasts become osteocytes: Bone is remodeled: Woven bone is remodeled and replaced by mature lamellar bone. 78 Importance of cartilage-bone interface in endochondral bone formation 79 CARTILAGE Rigid and firm but not ordinarily calcified. Provides three basic growth factors: flexible yet supports structure pressure tolerance in sites with compression a growth site in conjunction with enlarging bones Cartilage grows both appositionally 80 BONE Tension adapted and cannot grow directly in heavy-pressure areas Its growth is dependent upon its vascular osteogenic covering membrane “Growth cartilages” appear where linear growth is necessary toward the direction of pressure, allowing the bone to lengthen towards the force area and yet grow elsewhere by membranous ossification in conjunction with all periosteal and endosteal surfaces 81  Bone growth involves: Two basic processes: Deposition and Resorption. MECHANISMS Remodeling occurs due to tissue growth in different bone areas. OF BONE Key Points: GROWTH Bone shape changes during growth (remodeling). Deposition > Resorption = Bone enlarges and relocates. 82 DEPOSITION - the process whereby new bone is formed RESOPTION- process where existing bone is broken down and removed BONE REMODELING - process that replaces old bone with 83 new bone DEPOSITION AND RESORPTION ARE THE DYNAMIC PROCESSES OF BONE TISSUE REMODELING, ESSENTIAL FOR THE GROWTH OF THE CRANIOFACIAL SKELETON GUIDING ITS GROWTH, ADAPTING IT TO FUNCTION, AND ENSURING IT REMAINS STRONG, AND AESTHETICALLY PLEASING THROUGHOUT LIFE,, PARTICULARLY IN THE DEVELOPMENT OF THE JAWS AND FACIAL BONES 84  The process of deposition and resorption together is called bone remodelling Deposition occurs on the surface facing the direction of growth, new bone is added Resorption is seen on the surface facing away, bone is taken away The result is a process termed cortical drift 85  Cells that are responsible for deposition and resorption Osteoclasts- dissolves old and damaged bone tissue so it can be replaced with new, healthier cells created by osteblast Osteoblasts- form new bones and add growth to existing bone tissue 86  Cortical drift - growth movement where external surface of bone moves in particular direction lead to changes change in change in proportion size change in change in relation with shape adjacent structure 87 ORTHODONTICS Enlow’s V Principle 88  Enlow’s V Principle Enlow's 'v' principle was given in 1982 by DONALD H. ENLOW. It is the most useful and basic concept of facial growth. 89 Enlow’s V Principle 90  Bone Remodeling 91  Bone Remodeling Remodeling involves simultaneous deposition and resorption to shape bones and adapt to functional demands. 92 Types of Remodeling: a. Biochemical remodeling b. Growth remodeling c. Haversian remodeling d. Pathological 93 Types of Remodeling Growth remodeling: Bone replacement Biochemical remodeling: Maintains during childhood. mineral homeostasis. 94 Types of Remodeling Pathological: Regeneration Haversian remodeling: after trauma or disease. Cortical reconstruction in vascular bone. 95 Function Remodeling ensures regional adjustments for proper bone fitting. Active during childhood and adolescence; slows down in adulthood. 96 Growth Movement 97 Growth Movement Epiphyseal Plates (Growth Plates): Cartilage regions at the ends of long bones where growth occurs, these plates gradually ossify and fuse as the individual reaches full height. 98  Growth Movement Growth movements involve cortical drift and displacement, which enable craniofacial bones to enlarge and adapt to their functional environments. These movements are critical for maintaining relationships between growing bones and surrounding structures. 99 ORTHODONTICS Drift 100  DRIFT the process where a portion of a bone in the skull and face gradually remodels and shifts its position due to bone deposition on one side and resorption on the other 101  DRIFT Contrast with displacement: While drift is a localized remodeling process, displacement refers to the movement of a whole bone as a unit to a new position due to the growth of adjacent structures. 102 ORTHODONTICS DISPLACEMENT 103  DISPLACEMENT Movement of the bone as a whole unit. Growth remodeling simultaneously maintains relationships of the bones to each other. For some instances, as the entire mandible is displaced from its articulation in the glenoid fossa, it is necessary for the condyle and ramus to grow upward and backward to maintain relationships. 104  DISPLACEMENT Primary Displacement A process of which the condylar neck, coronoid process, and ramus remodel to accommodate the displacement. They also grow in size and sustain basic shape. Displacement associated with the bone’s own enlargement. Secondary Displacement Movement of a bone related to enlargement of other bones. 105  DISPLACEMENT Drift and displacement occur together and complement each other. May take place in contrasting directions, Difficult to determine the separate contributions of remodeling and displacement during cephalometric analyses. Separate processes. 106 107  108 Genetic Theory Assumptions that genes determine all aspects of facial form. Little correlation between facial features of parent and child. Evidence supports polygenic inheritance.  Sicher’s Hypothesis Suggests that primary growth of the craniofacial skeleton was genetically regulated within the sutures and cartilages. Suture growth was regarded as being the prime mediator of bony expansion. In the case of the maxilla, downward and forward displacement relative to the anterior cranial base. 109  Scott's Hypothesis (Nasal Septum) cartilaginous structure particularly nasal septum act as a primary growth center of the skull driving facial growth Cartilage of nasal septum paced the growth of maxilla Sutural growth response to the growth of other structures 110  Lantham’s refinement Combine ideas of Scott’s, Sicher, and Moss Emphasized role of Septo-premaxillary ligament which connects nasal septum to the maxilla initiating growth beginning in the later part of fetal period felt the maxillary sutures began as sliding joints adapting to initiating growth forces later manifest osteogenesis 111  Growth of maxilla Cartilage of nasal septum serves as a pacemaker for the growth of maxilla cartilage growth leads to forward and downward translation of maxilla sutures serves as a reactive area responds by new bone formation leading to growth 112  Experiments that verify Scott's theory TRANSPLANTATION EXPERIMENTS CARTILAGE REMOVAL EXPERIMENTS 113 Experiments that verify Scott's theory TRANSPLANTATION EXPERIMENTS involved transplanting different types of cartilage to see if they continued to grow in their new location. Epiphyseal plate of long bone: Continued to grow well in the new location. Spheno-occipital synchondrosis: Also grew, but not as well as the epiphyseal plate. Nasal septal cartilage: Found to grow nearly as well as others. Mandibular condyle: growth was observed when transplanted 114 TRANSPLANTATION EXPERIMENTS 115 TRANSPLANTATION EXPERIMENTS 116 Experiments that verify Scott's theory Cartilage Removal Experiments Extirpating a young rabbit's septum causes a considerable deficit in growth of the midface 117 Cartilage Removal Experiments 118  Moss’s Theory Bone and cartilage do not have genetic programing to control their own growth and lack growth determination Growth of bone and cartilage is primarily driven by the growth of surrounding soft tissues termed as "functional matrices” 119  Moss’s Theory Functional matrices these are non- Functional matrices eg; skeletal tissues that interact and muscle influence growth of bone and nerves cartilage and perform essential blood vessels function fat teeth skeletal tissue support and protect spaces filled with fluids associated functional matrices ( like oral cavity) 120 Moss hypothesis functional matrices TWO TYPES OF FUNCTIONAL MATRICES 1. Periosteal Matrices - deposition and resorption of bone, affecting its shape and size 2. Capsular Matrices - spaces or cavities that must remain open for the proper function of organs, necessitates the growth of surrounding bones. 121 PERIOSTEAL AND CAPSULAR MATRICES 122  Petrovic’s Hypothesis (servosystem) It is the interaction of a series of casual change and feedback mechanisms that determines the growth of the various craniofacial regions According to the servosystem theory of facial growth, control of primary cartilages takes a cybernetic form of command, whereas, in contrast, the secondary cartilages comprise not only the direct effect of cell multiplication but also indirect effects. 123  Petrovic’s Hypothesis (servosystem) In his experiments, Petrovic detected no genetically predetermined final length for the mandible. The direction and magnitude of condylar growth variation are perceived as quantitative responses to the lengthening of the maxilla. 124 Controlling Factors of Craniofacial Growth 125  Controlling Factors of Craniofacial Growth 1. NATURAL Van Limborgh has divided the factors controlling skeletal morphogenesis into 5 groups: Intrinsic genetic factors Local epigenetic factors General epigenetic factors Local environmental influences General environmental influences 126  Controlling Factors of Craniofacial Growth a. GENETICS Garn et. al. report similarities in fatness in families as a cohabitational effect, suggesting that living together and consuming the same food result in measurable similarities. 127  Controlling Factors of Craniofacial Growth a. GENETICS What we sometimes assume to be genetic may be acquired and superimposed on a genetic foundation common to parents and progeny. 128  Controlling Factors of Craniofacial Growth a. GENETICS Such a discontinuous distribution is evidence for simple Mendelian inheritance. A continuous distribution of a variable, with most values grouped around a mean, is evidence for inheritance from several or many genes. 129  Controlling Factors of Craniofacial Growth a. GENETICS Van Limborgh reports experimental studies on chick embryos indicating that the intrinsic genetic information necessary for the differentiation of cranial cartilages and bones is supplied by neural crest cells. 130  Controlling Factors of Craniofacial Growth a. GENETICS Primary genetic control determines certain initial features (e.g. tooth buds calcify in the jaws and mandible forms in faces). Secondarily, there are inductive local feedback and inner communication mechanisms between cells and tissues. 131  Controlling Factors of Craniofacial Growth a. GENETICS The teeth “talk to” the bone, the muscles “talk to” the bone, and the bone “talks back” to the muscles. What is environment to the bone is genetic to the muscles to the muscles and teeth: Van Limborgh’s “epigenetic factors” 132  Controlling Factors of Craniofacial Growth a. GENETICS If the face were under rigid genetic control, it would be possible to predict features of children from cephalometric data of the parents. A number of studies illuminate this particular point: the best involved parents whose children have achieved maturity, so that little growth is yet expected from them. 133  Controlling Factors of Craniofacial Growth a. GENETICS Given multifactorial controls, it can be shown that the highest correlation between parents and progeny can only be a correlation of r =.5. This can be compared to the correlation for blood type, namely, = 1.0 between parents and progeny. 134  Controlling Factors of Craniofacial Growth a. GENETICS Squaring the correlation coefficient enables one to arrive at the amount of variation explained or predicted for one variable in the correlation by the other. Thus a correlation of 0.5 enables one to predict only 25% of a child's mandibular size from knowledge about the parents' mandibular sizes. 135  Controlling Factors of Craniofacial Growth a. GENETICS Since the usual correlation between parents' and children's dimensions is about 0.3, something less than 15% of children's dimensions are predictable or explained by parents' dimensions. 136  Controlling Factors of Craniofacial Growth a. GENETICS 1. Inheritance of facial dimension is polygenic. 2. No more than one-fourth of the variability of any dimension in children can be explained by consideration of that dimension in parents. 137  Controlling Factors of Craniofacial Growth a. GENETICS SUMMARY: It is highly unlikely that any component of the facial skeleton is inherited in the Mendelian fashion. Rather, the evidence strongly supports polyenic inheritance, greatly limiting our ability to explain facial dimensions from study of parents. 138  Controlling Factors of Craniofacial Growth a. GENETICS SUMMARY: Even if the size of facial bones were inherited in Mendelian fashion, that inherited pattern is altered by environmental influences, some epigenetic and some general, to such an extent that in the patient the underlying genetic features cannot be easily detected. 139  Controlling Factors of Craniofacial Growth B. FUNCTION Importance of Function Normal function is critical for skeletal growth. Absence of function ( temporomandibular ankylosis, aglossia, neuromuscular disorders) leads to severe bony morphology distortion. 140  Controlling Factors of Craniofacial Growth Aglossia Neuromuscular Disorders Absence of the tongue causing Temporomandibular Ankylosis difficulties in speech and Conditions impairing Fusion of the TMJ leading to swallowing. nerve-muscle function, restricted mouth opening and causing weakness and functional limitations coordination issues. 141  Controlling Factors of Craniofacial Growth B. FUNCTION Primary Control Factor Function acts as the primary factor controlling craniofacial growth. Core concept: Moss' "Functional Matrix Hypothesis." 142  Controlling Factors of Craniofacial Growth B. FUNCTION Role of Malfunction Malfunction causes compensatory abnormal growth. Refer to Section D-2-d (Disruptive Factors, Malfunction). 143  Controlling Factors of Craniofacial Growth B. FUNCTION Key Understanding Sites of compensatory growth adapt to altered function. Refer to Section E (Regional Development) for detailed adaptive responses. 144  Controlling Factors of Craniofacial Growth C. GENERAL BODY GROWTH Biological Maturity: Influences all aspects of individual maturation. Factors: genetic, climatic, racial, nutritional, socioeconomic. Somatic and Craniofacial Growth Relationship: Considerable interest in understanding the timing of body growth and craniofacial dimensional growth. 145  Controlling Factors of Craniofacial Growth GROWTH VELOCITY CURVE FOR HEIGHT Key Features: Height is the most studied dimension of growth. Velocity decreases continuously from birth except for: A small, inconsistent spurt at 6–7 years. A significant spurt during puberty. Pubertal Spurt in Stature Velocity is greatest during this time, often coinciding with orthodontic treatment. 146  Controlling Factors of Craniofacial Growth FACIAL GROWTH SPURTS Characteristics: Not all facial dimensions exhibit a spurt. Timing, onset, duration, and cessation vary among individuals. Generally aligns with the pubertal spurt in height. Peak Growth Ages: Girls: ~12 years (±1 year). Boys: ~14 years (±1 year). 147  Controlling Factors of Craniofacial Growth PREDICTING GROWTH SPURTS Challenges in Prediction: Growth spurts are difficult to predict until they are underway. Hand-wrist radiographs used for skeletal age and predicting Peak Height Velocity (PHV). Limitations: Hand-wrist radiographs and chronological age are not precise for clinical use. Population means are of limited value due to normal variation. 148  Controlling Factors of Craniofacial Growth SUMMARY Relationship: Somatic growth and craniofacial growth are related but challenging to predict precisely. Pubertal Spurt: The peak growth spurt in stature aligns with orthodontic treatment periods, but predicting facial growth spurts remains difficult. Clinical Utility: General growth information is helpful clinically, but its practical and precise application is often overstated. 149  Controlling Factors of Craniofacial Growth D) NEUTROPHISM Neurotrophism suggests that neural activity influences skeletal growth by transmitting signals through nerves. While it is logical, direct evidence for its effects on bone growth is lacking. 150  Controlling Factors of Craniofacial Growth D) NEUTROPHISM How It Works Neurotrophism likely impacts skeletal growth indirectly by affecting soft tissues, which then influence bone structure. This idea aligns with Moss' functional matrix hypothesis, which states that bone growth responds to changes in surrounding tissues. 151  Controlling Factors of Craniofacial Growth D) NEUTROPHISM Studies by Behrents and Moss suggest that neurotrophic mechanisms exist but have minimal direct effects on bone. Their primary influence seems to be through soft tissue changes, and distinguishing these effects from muscle-related impacts remains a challenge. 152  Controlling Factors of Craniofacial Growth D) NEUTROPHISM Overbite Correction with Braces 153  Controlling Factors of Craniofacial Growth D) NEUTROPHISM Conclusion Neurotrophism provides an intriguing explanation for neural influence on skeletal growth, primarily through soft tissues. Its overall role is minor, and further research is needed to clarify its mechanisms. 154  Controlling Factors of Craniofacial Growth 2) DISRUPTIVE FACTOR Facial growth can be affected by disruptive factors, which are changes or conditions that don't normally contribute to usual growth patterns. These factors can come from different sources: Elective causes Environmental causes Congenital causes 155  Controlling Factors of Craniofacial Growth A) ORTHODONTHIC FORCES Orthodontic forces are applied to influence facial growth and adjust tooth positions. Orthodontic forces stimulate changes in bone and soft tissues. To correct dental alignment and guide the development of the jaws. 156  Controlling Factors of Craniofacial Growth A) ORTHODONTHIC FORCES Localized changes depend on the type and direction of the forces applied. 157  Controlling Factors of Craniofacial Growth B) SURGERY Orthognathic or plastic surgery is performed for two main reasons: 1. To correct craniofacial anomalies (e.g., cleft palate). 2. To improve craniofacial esthetics in faces that deviate significantly from the norm. 158  Controlling Factors of Craniofacial Growth B) SURGERY Modern Advances in Surgery: Surgical techniques have greatly improved, enabling surgeons to reposition parts of the face with better precision. For example, jaw surgery can correct alignment issues to restore function and esthetics. 159  Controlling Factors of Craniofacial Growth B) SURGERY Challenges: 1. Relapse: Corrections may not hold, even in adults. 2. Growth Impact: Surgery on children can disrupt natural growth. Limited data exists on how surgery affects normal growth and craniofacial anomalies, requiring careful planning and long-term monitoring. 160  Controlling Factors of Craniofacial Growth B) SURGERY Cleft palate repair fixes structural issues but may alter jaw growth without proper follow-up. 161  Controlling Factors of Craniofacial Growth C) MALNUTRITION Although it is presumed that gross malnutrition affects craniofacial growth in humans (it has been studied in some animals), there is little specific information available. 162  Controlling Factors of Craniofacial Growth D) MALFUNCTIONS Their role in craniofacial morphology is well documented is well documented in the experimental labratory by classic research of Harvold, Petrovicc, McNamara, and Carlson. 163  Controlling Factors of Craniofacial Growth D) MALFUNCTIONS Clinical studies of the effects of altered nasorespiratory function on growth and morphology (Linder-Aronson) and posture (Solow and Tallgreen) 164  Controlling Factors of Craniofacial Growth D) MALFUNCTIONS Cleft lip and palate The enunciation of the functional matrix theory by Moss and the previous research give solid support to the idea that function helps determine morphology during Craniosynostosis normal growth and that altered function can produce altered morphology 165  Controlling Factors of Craniofacial Growth E) GROSS CRANIOFACIAL ANOMALIES Patients with this anomaly present a head and faced markedly altered during early organogenesis in ways hard to discern postnatally 166  Controlling Factors of Craniofacial Growth E) GROSS CRANIOFACIAL ANOMALIES Our knowledge of postnatal growth of some of the more common syndromes (like cleft palate) has become better in recent years, but in fundamental work is still needed. fortunately a number of fine research centers are dedicated to the understanding and treatment of these problems. 167 168 Growth of the cranium is divided into: Cranial Base Cranial Vault 169  Growth of the facial skeleton is divided into: Nasomaxillary complex or the maxilla Mandible 170  CHONDROCRANIUM DESMOCRANIUM Cartilaginous boxes protecting the Lateral walls and roof of the brain cage. brain and sensory organs, otic and Infant- at birth, the head of the infant is nasal membrane relatively large due to the advanced state of growth of the brain. Face forms 1/8 of the head. Adult face- occupies 1/3 to ½ the bulk of the head. The volume of the brain is almost complete by age of 14 171  GROWTH MOVEMENT SEEN DURING THE ENLARGEMENT OF CRANIOFACIAL BONE Cortical Drift ○ Gradual movement of the growing area of the bone. ○ It is a growth movement of the enlarging portion of a bone by , modeling action of osteogenic tissue. Displacement ○ Movement of whole bone as a unit and the physical movement as the. whole bone as it remodels. a. Primary displacement b. secondary displacement 172  GROWTH MOVEMENT SEEN DURING THE ENLARGEMENT OF CRANIOFACIAL BONE a. Primary displacement i. The amount of displacement equals the amount of new bone deposition. ii. The respective directions are always opposite. b. Secondary disaplacement i. Not related to its own growth ii. anterior growth of the middle cranial fossa and temporal lobes secondarily displace the nasomaxillary complex anteriorly and inferiorly. 173 The Cranial Vault The bone that covers the upper and outer surface of the brain made up of flat bone that are formed by intramembranous bone formation without cartilaginous precursors The cranium grows because the brain grows 5th year of life almost 90 % growth of the cranial vault is achieved 174 The Cranial Vault Remodeling and growth occur mainly at periosteum-lined contact areas between skull bones. At birth, the flat skull bones are widely separated by loose connective tissues, forming fontanelles. These allow the large head to pass through the birth canal. 175 The Cranial Vault After birth, apposition of bone along the edges of the fontanelles eliminates these open spaces fairly quickly, but the bones remain separated by a thin periosteum lined suture for many years, eventually fusing in adult life. 176  The Cranial Base Important Growth Sites: a. Spheno-occipital synchondrosis b. Intersphenoid synchondrosis c. Spheno-ethmoidal synchondrosis 177  The Cranial Base The cranial base grows primarily by cartilage growth in the sphenoethmoidal, intersphenoidal, spheno – occipital and intraoccipital synchondrosis, mostly following the neural growth curve. Activity at the intersphenoidal synchondrosis disappears at birth. 178  The Cranial Base The intraoccipital synchondrosis is a major contributor as the ossification here extends till the 20th year of life. 179  The Cranial Base The Important growth sites: 1. Intersphenoidal synchondrosis Between the two parts of the sphenoid bone and the activity in this area disappears after birth. 2. Spheno-occipital synchondrosis Between the sphenoid and occipital bones This does not stop until the 12 years of life This closes at the 17th year of life 180  The Cranial Base Place a role in vertical growth of the posterior part of the face and also contributes to the sagittal growth of the anterior part of the face were it borders the brain 3. Spheno-ethmoidal synchondrosis Between sphenoid and ethmoid bones Closes on the 3rd and 5th years of life 181  The Cranial Base What Makes the cranial base So Important? The cranial base supports the brain, protects vital structures, and guides skull and facial growth. Summary: The cranial base is the unpopular superhero of your skull, supporting the brain and guiding your face to grow like an expanding “V.” It works hard, grows smart, and shuts down operations at just the right time to give you that perfect balance of brain space and facial structure. 182 The Maxillofacial Complex Made up of the nose, maxilla, and the associated structures. The growth of the cranium and facial skeleton progress at different rates (Scammon). By differential growth, the face literally emerges from beneath the cranium. 183 The Maxillofacial Complex The upper face, under the influence of cranial base inclination, moves upwards and forwards; the lower face moves downwards and forwards on an expanding V”. Literally the mandible is an “EXPANDING V” 184 Active Growth Areas of the Mandible are: 1. Posterior border of ramus 2. Mandibular condyle and coronoid process 3. The alveolar process 185  The Mandible The unique growth mechanism of the mandibular condylar region employs both interstitial and appositional proliferation. Appositional growth along the posterior border of the ramus, alveolar margin, inferior margin of the mandibular body, and, to a lesser extent, the lateral surfaces, contributes to the size increase. Simultaneously, resorption on the anterior ramus margin extends the dental arch length. 186 187  Dynamics of Facial Growth Facial growth is a highly intricate process where form (the shape and structure of the face) and function (how the facial structures work together) are influenced by multiple factors. 188 Dynamics of Facial Growth 1. Morphogenetic patterns: refer to the processes that lead to the formation and organization of the shape and structure of an organism. These patterns are influenced by genetic information, but they also involve other factors like environmental signals, cellular communication, and 189 biochemical gradients. Dynamics of Facial Growth Environmental Influences: Habits, nutrition, and mechanical forces (e.g., chewing, breathing) play a role in shaping the face. Epigenetic Factors: Influences beyond genetics, such as how genes are expressed due to environmental factors. 190 191  Dynamics of Facial Growth Differential Growth is a cornerstone concept, which means that not all parts of the face grow at the same rate or time. For example: Cranial Growth (skull): Reaches near-adult size much earlier than the face. Facial Growth: Height grows the most, followed by depth (front-to-back growth), and then width. 192  Dynamics of Facial Growth Understanding the mosaic of the morphogenetic pattern (the complex arrangement of growing facial tissues) helps orthodontists plan treatments that align with natural growth periods, ensuring interventions are both timely and effective. 193  Dynamics of Facial Growth Thus, many studies of growth we need to take into consideration, i.e Time or timing of treatment. As Orthodontic and orthopedic interventions must be aligned with growth spurts and developmental milestones for better outcome. 194  Dynamics of Facial Growth Growth spurts are sex-linked Longitudinal studies have been made by the author on normal children and those with cleft palate from six years of age. Significantly, it marked the difference in the rate of growth. 195  Dynamics of Facial Growth Not only is the rate of growth for both normal and cleft palate children highly variable, but the direction of growth at a particular time is occasionally unpredictable. Similar studies made on orthopedic patients between the ages 11 and 19 years also shows varying rates of growth accomplishment and directional change. 196  Dynamics of Facial Growth A number of investigators point out the sex- linked nature of growth, with female pubertal spurts occurring ahead of that of male. Means that Sex-Based Variation must need to be taken into consideration as differences in growth patterns between males and females necessitate gender-specific approach to treatment timing. 197  Dynamics of Facial Growth Woodside, in his study of the Burlington group, points out that growth spurts are really possible. They seem to be sex-linked. The greatest increments of growth are actually at the 3 year age level. The second peak is from 6-7 years in girls and 7-9 years in boys. The third peak is 11-12 years in girls and 14-15 years in boys. 198  Dynamics of Facial Growth Male (114) Female (104) One Peak 7 35 Two Peaks 73 64 Three peaks 34 5 199 ORTHDONTICS 1 References GROUP 2 ORTHDONTICS THANK YOU FOR LISTENING GROUP 2 201