Orthodontic Introduction (LEC 1) PDF

LEC : 1 ORTHODONTICS ‫دثامر هاني الصفار‬ Orthodontics is the oldest specialty in the dental profession. Orthodontics (Ortho =Straight, Dontic = Teeth), is that branch of dental science concerned with genetic variation and development and growth of facial form....

LEC : 1 ORTHODONTICS ‫دثامر هاني الصفار‬ Orthodontics is the oldest specialty in the dental profession. Orthodontics (Ortho =Straight, Dontic = Teeth), is that branch of dental science concerned with genetic variation and development and growth of facial form. It is also concerned with the manner in which these factors affect the occlusion of the teeth and the function of associated organs. Therefore we are not only concerned with straightening of the teeth, but also the growth, development, and function of the total orofacial complex. INDICATIONS FOR ORTHODONTIC TRETMENT: 1. Unattractive facial esthetic. 2. Dysfunction of TMJ. 3. Susceptibility to dental caries. 4. Susceptibility to periodontal disease. 5. Impaired speech caused by malposition of teeth and\or jaws. CONTRAINDICATIONS OF ORTHODONTIC TREATMENT: 1. Poor oral hygiene and lack of cooperation. 2. Lack of bony support for the dentition. 3. Poor general or mental health. 4. Lack of interest. Benefits of orthodontic treatment: Orthodontic treatment may aid in eliminating or reducing three types of adverse effect for the patient: 1.PSYCHOSOCIAL FUNCTION Severe malocclusion & dental facial deformities strongly influences child self-esteem and if left untreated it can cause difficulty in psychological and social adjustment as the child matures. 2. ORAL FUNCTION: Malocclusion may compromise oral function:  1. Difficulty in chewing. 2. Jaw discrepancy change manner of swallowing. 3. Difficulty for certain speech sounds. 4. TMJ joint pain from minor imperfection in occlusion (clenching & grinding). 3. DENTAL DISEASE: Malocclusion can contribute in: 1. dental decay :mal-alignment of the teeth may reduce the potential for natural teeth cleansing and increase risk of decay 2. periodontal disease: because of difficulty in maintaining good oral hygiene due to lack of normal occlusion and natural cleansing benefits. 3. Trauma to anterior teeth: studies refer that overjet more than 3mm and more increase the risk of traumatic injuries to anterior teeth. 4. Impacted teeth may affect normal position and the health of adjacent teeth and loss function of the impacted tooth irself. OCCLUSION When the teeth in mandibular arch come into contact with those in maxillary arch in any functional relation are said to be in occlusion. (WHEELER’S) IDEAL OCCLUSION  A theoretical concept of an ideal arrangement of teeth within the dental arches combined with an ideal inter-arch relationship ,which concentrates optimal esthetic.function, and stability of the dentition and supporting structures.But it is almost never found in nature. Normal Occlusion : That occlusion which satisfies the requirements of function and esthetic but in which there are minor irregularities of individual teeth. It implies a situation commonly found in the absence of disease. It should include not only a range of anatomically acceptable values but also physiological adaptability.It is always a range never a point. Andrews Six Keys To Normal Occlusion LAWRENCE F.ANDREWS(1972) - collection of 120 models of teeth with naturally excellent occlusion Criteria for selection 1. Had never undergone ortho treatment 2. Were straight & pleasing in appearance 3. Had a bite which looked generally correct 4. In his judgement, would not benefit from ortho treatment  MOLAR RELATIONSHIP  The mesio-buccal cusp of the upper first permanent molar should made contact and occluded with the mesial surface of the mesio buccal cusp of the lower second molar.  CROWN ANGULATION The gingival portion of the long axis of each crown should be distal to the incisal portion. The degree of crown tip is the angle between the of long axis of the crown to a line perpendicular to the occlusal plane.  CROWN INCLINATION  Refers to the buccolingual inclination of the long axis of crown, not to the long axis of entire tooth. Determined by resulting angle between a line perpendicular to the occlusal plane and a line that is tangent to the middle of the labial or buccal clinical crown. A ‘plus’ reading is given if the gingival portion of the tangent line is lingual to the incisal portion.A ‘minus’ reading is recorded when the gingival portion of the tangent line is labial to the incisal portion. Most maxillary incisors have a positive inclination; mandibular incisors have a slightly negative inclination.All posterior teeth have lingual crown inclination (negative inclination) ROTATIONS Absence of rotations Arch should be devoid of any rotated tooth. A rotated molar occupies more mesiodistal space. A rotated incisor occupies less space.  TIGHT CONTACTS In absence of abnormalities such as genuine tooth size iscrepancies, contact point should be tight.It should be free of spacing.  OCCLUSAL PLANE The curve of spee given by F. Graf Von Spee in Germany in 1890 It refers to the antero-posterior curvature of the occlusal surfaces beginning at the tip of the mandibular cusped and following the buccal cusps of bicuspid and molar continuing as an arch through the condyle. An excessive curve of spee restrict the amount of space available for the upper teeth results in crowding. A flat curve of spee is most receptive for normal occlusion.(the mandibular curve of spee should not be deeper than 1.5mm) Risk of orthodontic treatment 1-The roots of teeth resorption All brace work causes minor changes to the roots of the teeth. This is not usually a problem. Occasionally, changes to the roots can be more serious. It is often possible to tell if someone is at risk, but not always. 2-Teeth be painful teeth are likely to be sore for about 3-5 days after the brace is fitted and each time it is adjusted. If necessary ,pain killers such as the ones you would normally take for a headache may help. Please follow the instructions on the packet. If your brace rubs your lips or cheeks, you can be given a product to help with this. It is sensible to contact your orthodontist if your teeth are very painful. 3- loss of periodontal support caused by poor oral hygiene during orthodontic treatment. 4-Demineralisation of teeth may occur during fixed orthodontic treatment specially as a result of plaque accumulation in case of uncooperative patient (poor oral hygiene). 5- soft tissue damage: traumatic ulcerationmay occur specially in fixed orthodontic treatment. 6-pulpal injuries: Excessive orthodontic force may lead to pulp injury and death especially for teeth with history of trauma. 7-Relaps of orthodontic treatment: Orthodontic treatment should be successful. it will need to look after teeth and brace well, follow the orthodontist’s instructions and attend regularly to have the brace adjusted. During the orthodontic treatment check the teeth and gums are healthy.