TOPIC: «Orthopedic dentistry as the medical science. Organs of masticatory system and their function» Teacher : Dudina I. L. Plan of the lecture: 1. Orthopedic dentistry as medical science; 2. Dental and technician apartments 3. Organs of maxilla-facial system "Orthopedics" prevention and correction of musculoskeletal system disorders Dentistry prevention, diagnosis, and treatment of diseases and disorders of oral cavity, maxillofacial region, and associated structures orthopedic dentistry recognition, prophylaxis and treatment of hereditary and gained diseases or deformations of dental-maxilla-facial system by using of orthopedic methods (devices and prostheses) The goals of orthopedic dentistry: 1. To improve methods of diagnostics, prophylaxis, treatment of dental-maxilla-facial system’s diseases; 2. To provide qualified dental aid to the patients; 3. To widen knowledge concerning physiological and pathological processes before and after treatment. The tasks of orthopedic dentistry: 1. To provide prophylaxis, early diagnosis, treatment of dental-maxilla-facial system diseases by using of orthopedic methods; 2. To provide rehabilitation procedures after treatment; 3. To provide regular medical check-up of the patients. ORTHOPEDIC DENTISTRY Propedeutic course · anatomical-physiological features of masticatory apparatus; · methods of patient’s examination; · signs of illness; · material science; · laboratory technique. The main course · prosthodontics; · maxilla-facial orthopedics; · orthodontics Scheme of a dental room (14m2 for 1 dental unit and + 7m2 to each added dental unit) Square for 1 dental unit is 14m2 + 7m2 for additional one 1. Dental unit; 2. Dental arm-chair; 3. assistant‘s table; 4. assistant‘s chair; 5. dentist‘s chair; 6. Table for instruments; 7. Cabinet for medicines; 8. Draught; 9. Couch 10. sink; 11. Gypsum table. Scheme of a dental laboratory apartment In dental policlinic or separated Accident prevention · To work wearing a working clothes (surgeon’s coat, cap); · To work with protective gloves, plastic cover, glasses; · To work with saliva ejector, dust separator; · To wash hands with special disinfectants; · Impressions, prostheses and other materials must be disinfected properly; · Disposable instruments must be destroyed immediately after using, others - sterilized; · to start working with patient from taking his history; · To be careful using sharp instruments · To use earth connection to electrical devises, don’t use apparatus' out of order or you don’t know their mode of operation; · To be careful using harmful liquids (sulfuric acid, hydrogen peroxide). Maxillofacial system composed of: - Skeleton; - Teeth; - Masticatory and mimic muscules; - Organs which take part in forming of food bolus; - Salivary glands; - Temporo-mandibular joint (TMJ). Functions of the musular-facial system include: · Feeding (mastication) · Phonation and Vocalization · Breathing Permanent teeth The simple formula of permanent teeth 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 Formula of permanent teeth by WHO I II 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 IV III Tooth formation Anatomical neck of the tooth is the border between crown and root (the thinnest part of the tooth) Clinical neck of the tooth is the thinnest part of the crown which is located above the gum Surfaces of teeth Incisors and canines: 1. Vestibular 2. Palatal or lingual (oral) 3. Medial and distal contact 4. Scalprum Premolars and molars: 1. Vestibular 2. Palatal or lingual (oral) 3. Medial and distal contact 4. Chewing or occlusive Dental archs (dentitions) semi-elliptical shape Parabolic shape Occlusal curve – the line which connects 1. sculprums and vestibular cusps in saggital plane 2. vestibular and oral cusps in transversal plane occlusal surface – the plane of chewing surface of teeth Saggital occlusal curve first described by E. Spee (1890). and forms concave curve from premolars to the last molar. The deepest place - is the occlusal surface of the first lower molar. Upper dental arch in the area of premolars and molars has sagital protuberant curve that congruous to the lower curve. Transversal occlusal curve (Wilson’s curve) Cheek cusps of upper premolars and molars are at more high level, than lingual. Transversal line united the cusps is a concave transversal curve. basal arches ( )of upper and lower jaws (line through the apexes) dental arches ( ) of upper and lower jaws (line through the crowns of teeth) alveolar arches ( ) of upper and lower jaws (line through the roots of teeth) On the lower jaw basal arch is the biggest; dental – is the smallest. On the upper jaw basal arch is the smallest; dental – the biggest. Periodontium (periodontal ligament) - dense connective tissue located in space between wall of alveolus and root surface Main functions: · supporting (as a ligament); · amortizing (lowing the pressure); · pressure distributive, sensitive (has baroreceptors); · protective (has lymphatic cells); · trophic (has blood vessels, nerves). Reserved strength of periodontium is the ability to adjust to masticatory perssure (goes down with ageing and in case of periodontium diseases). Dentitions have supporting mechanism to protect of dental arches from deformations: 1. Presence of tooth-antagonists (opposing teeth); 2. Presence of tooth-synergists (adjacent teeth); 3. three dimensional orientation of teeth (trapezium shape of vertical axes of teeth-antogonists); Hard palate concave upward Palate is divided into 3 regions: 1. Plicae transversae area; 2. Middle area; 3. Back one-third area. Innocents have plane palate with most evident cross folds. With ageing and permanent teeth eruption there is a process of making it concave upward shape with less prominent transversal fold. With teeth loss the shape of hard palate becomes flat again. Soft palate – is formed by muscles and glandular tissue covering the muscles 1. - m. Tensor veli palatini; 2. - m. levator veli palatini; 3. - hamulus pterygoideus; 4. - m. palatoglossus; 5. - m. uvulae; 6. - m. palatopharyngeus. The functions of soft palate: 1. To separate the respiratory tract from digestive system; 2. To provide the sound making. Mucous membrane of the oral cavity Transitional plicae are formed in area of alveolar process mucous membrane ends and cheek and lip mucous membrane begins. There are two kinds of mucous membrane: mobile and immobile. Mobile mucosa has strongly pronounced submucosal layer. Immobile mucosa is connected to the periosteum and does not have strongly pronounced submucosal layer. Masticatory muscles · Elevators: m. masseter, m. temporalis, m. pterygoideus med. (provide saggital movements of the mandible); · Muscles pulling the mandible forward and sideways: m. pterygoideus lat. (provide protrusive and transversal movements); · Depressors: m. geniohyoideus, m. mylohyoideus, m. digastricus (provide saggital movements of the mandible). Synergism of masticatory muscles – the group of muscles which perform the same function Antagonism of masticatory muscles - the group of muscles which perform inverse function Relative rest of masticatory muscles - is the state of minimum muscular tension or physiological equilibrium of muscles lifting and downing the mandible. Mimic muscles Masticatory muscle strength and pressure · Absolute strength – the maximum muscle’s force in its constraction; · Relative strength (masticatory pressure) – force of muscles which do on the certain surface in process of mastication. Reflexes of masticatory apparatus 1. gingiva-muscular reflex (gingiva has receptors to stop muscular contraction in case of over strength); 2. periodontium-muscular reflex (periodontium has reseptors to stop muscular contraction in case of over strength which might be destructive); 3. muscular-muscular reflex (muscles have proprioreceptors to stop muscles’s contraction if the force might tear the muscular fibres). The ways to transmit of masticatory pressure from occlusal surface to scull base – thickening of cancellous tissue (counterforts) Trajectories of the mandible Temporomandibular joint Difference between TMJ structure in human and animals Articulation - all the positions of the mandible during its movements Central occlusion; Frontal occlusion; Right lateral occlusion; Left lateral occlusion. Distal occlusion Signs of centric occlusion Contacts between tooth-antogonists in central occlusion Gyzi: scheme of mastication Saggital angles · Saggital incisor angle - formed by crossing the line laying on extension of saggital incisor track and occlusal plane · Saggital articular angle - formed by crossing the line laying on extension of saggital condylar track and occlusal plane Transversal angles Transversal angles · Transversal incisor angle - formed on crossing the incisor lines in sideway mandible’s movements · Transversal articular angle - angle between frontal and lateral condylar movements on nonworking side Bite - is the name of relations between dental sets of upper and lower jaws in central occlusion (The alignment of the teeth of the upper and lower jaws when brought together.). Compensated bite – the bite in which protrusive movements give all the tooth-antogonists to be in contact Subcompensated bite – if in frontal occlusion there are two areas of contacts: between central incisors and between last molars Decompensated bite has only one area of contact of teeth – frontal area image4.jpeg image5.jpeg image6.png image7.png image8.png image9.png image10.jpeg image11.jpeg image12.png image13.jpeg image14.png image15.png image16.png image17.png image18.png image19.png image20.png image21.png image22.jpeg image23.jpeg image24.png image25.png image26.png image27.png image28.png image29.png image30.png image31.png image32.png image33.png image34.png image35.png image36.png image37.png image38.png image39.jpeg image40.jpeg image1.png image2.png image3.jpeg