Preclinical dentistry I. 1.lecture Doc. MUDr. Lenka Roubalíková, Ph.D. lroubal@med.muni.cz +420 607 122 064 2 Enamel Dentin Cementum Dental pulp Periodontal tisues Restorative dentistry Diseases of hard dental tisues, dental pulp and periodontal tissues (of pulpal origin) Aethiology, ,pathogenesis,diagnosis,therapy and prevention. Diseases of hard dental tissues Congenital – genetic reasons Postnatal - Before eruption - After eruption Congenital • Amelogenesis imperfecta Enamel is affected • Dentinogenesis imperfecta Dentine is affected Before eruption • Hypomineralization (white, brown spots) • Defects of enamel (hypoplasia) Reasons - local (inflammmation, traumatic dental injuries) - systemic (systemic diseases, antibiotics) After eruption • Dental caries • Trauma • Attrition, abrasion • Erosion • V-shaped defects Antony van Leeuwenhoek (1632 – 1723) nizozemský přírodovědec a vynálezce. Obchodník v Amsterdamu a vědec samouk, byl členem královské společnosti. Zhotovil jednoduchý mikroskop s jedinou čočkou, který zvětšoval 300krát. Prostudoval řadu mikroorganismů a popsal jejich způsob života. Mj. objevil krevní kapiláry, jako první podal v roce 1683 přesný popis bakterií a prvoků, popsal příčné pruhování svalů. Popisem buněčné stavby rostlin se stal jedním ze zakladatelů rostlinné anatomie. First observation of microbs in oral cavity 17.century Dental caries • Willoughby Dayton Miller (1853 -1907) • Explanation – theories Miller´s theory: chemical – bacteriogical explanation Origin of dental caries • Dental caries originates as decalcification of hard dental tissues. This decalcification is caused by microbs that are present on tooth surfaces in the dental biofilm. These microbs utilize sugars. • After this decalcification also the decomposition of organic substances follows due to proteolytic microbs. Dental biofilm – plaque. Pelicle • A layer of proteins from saliva that precipitate on the tooth Dental biofilm • Adherence Dental biofilm • Colonization and coaggregation Dental biofilm • Maturation lenka.roubalikova@tiscali.cz 16 Dental bioífilm Comunity More species, Better conditions for survival Higher resistancy Higher virulency Mikrobs Hard dental tissues Time Sugars Metabolic activity lenka.roubalikova@tiscali.cz 18 pH 0 50 min 5,0 Stephan Dissolving of enamel lenka.roubalikova@tiscali.cz 19 Ca2+ PO4 3- F- Ca2+ PO4 3- Ca10(PO4)6(OH)2 Ca10(PO4)6F2 OH- lenka.roubalikova@tiscali.cz 20 Demineralization Time Irreversibil: non cavitated lesion Reversibil: Initial (non cavitated) lesion Non cavitated lesion can be healed Cavitated lesion must be drilled and filled Dental caries is multifactorial disease • Essential factors • - necessary • Co condition factors • - not necesasary but can influence the expansion Co commitans factoras • Quality of hard dental tissues and position of teeth • Food – composition and consistency • Systemic health • Age • Heredity (liking of sweetness?) • Climate Caries danger areas • Pits and fissures • Proximal surfaces below the contact point • Cervical third of dental crown (area below the maximum convexity) • Exposed root = habitually unclean areas 25 Habitually clean places • Incisal edges • Cusps and their slopes • Areas above the maximal convexity • Enamel ridges : transverse ridge, oblique ridge Classification of dental caries Acc to topograpoy • Coronal caries • Root surface caries According to affected surfaces - See classification acc to Black According to affected tissues • Caries in enamel • Caries in dentin • Caries in cementum Classification of dental caries According to its depth • Surface caries (caries superficialis) • Middle caries (caries media) • Caries next to dental pulp (caries pulpae proxima) • Caries penetrating into dental pulp (caries ad pulpam penetrans) Deep caries Surface caries Middle caries Caries next to dental pulp Caries penetgrating into dental pulp Classification of dental caries According to history • Acute • Chronic • Arrested Classification of dental caries According to origin • Primary caries • Secondary caries • Recurrent caries Primary caries Secondary caries Recurrent caries Penetrating caries Undermining caries Green Vardiman Black (1836 – 1915) American professor Established the scientific bases of dentistry Formulated basic rules of preparation of cavities Developed the guidelines for amalgam fillings including the optimal composition of amalgam (balanced alloy) Preparation Preparation is an instrumental treatment of the tooth that has been damaged by dental caries in such a way that - the reconstruction of this tooth is possible - the filling does not fall out - the tooth as well as the filling can face up to occlusal forces - the risk of the caries on treated surface si minimal (Black 1914) Preparation Preparation is an instrumental treatment of the tooth that has been damaged by dental caries in such a way that - the reconstruction of this tooth is possible - the risk of the caries on treated surface si minimal- extention for prevention - the filling does not fall out - retention - the tooth as well as the filling can face up to occlusal forces - resistance (Black 1914) • After we understand the reasons of dental caries we will be able it to heal it (Black 1900) lenka.roubalikova@tisca li.cz 44 Classification acc. to Black • Class I. Pit and fissure caries lenka.roubalikova@tisca li.cz 45 Classification acc. to Black • Class II. Proximal surfaces in premolars and molars lenka.roubalikova@tisca li.cz 46 Classification acc. to Black • Class III. Proximal surfaces of incisors and canines without lost an incisal ridge lenka.roubalikova@tisca li.cz 47 Classification acc. to Black • Class IV. Proximal surfaces of incisors and canines with lost an incisal ridge lenka.roubalikova@tisca li.cz 48 Classification acc. to Black • Class V. cervical lesions Clasification acc. to black • VI. Class • Caries on incisal edges (abraded) Sequence of operations Acces to the cavity Preparation through the hard dental tissues Removal the undermined enamel Separation of teeth Separation or removal of gingiva Prepration through hard dental tissues Breaking the enamel Removal of the undermined enamel Separation with wooden wedge Removal of the old filling Removal of the ingrown gingiva Sequence of operations Acces to the cavity Establishment of the cavosurface margin extention for prevention Retention of the filling Resistance of the restored tooth ( the filling as well as the restoration) Excavation of carious dentin Protection of dentin wound Finishing of the walls Final control (light, miror, magnification) Sequence of operations Preparation of cavity borders and extention for prevention (Cavosurface margin) Depends on Dental material Oral hygiene Precautions of secondary caries Sequence of operations Retention of the filling Precautions of its lost Macromechanical retention Micromechanical retention Chemical retention Sequence of operations Resistance of the restored tooth Against occlusal and other forces Depends on - Material - Individual occlusal forces Sequence of operations Excavation of carious dentin Necessary (risk of recurrent caries) Ball shaped (spheric) bur - slow speed (3000 rpm) or Excavator (hand instrument) Sequence of operations Finishing of the walls Depends on the kind of material - Bevel or without bevel - Fine diamond bur Protection of dentin wound • Filling itself • Base (below the filling – protection against thermal exposure ot toxiccity of dental materials) Sequence of operations Final control Direct or indirect view Good illumination Magnification Preparation • Hand Excavator, cleaver • Power driven • Rotary • Non standard preparation Burs, diamonds Chisel – for enamel Cleaver Chisel for enamel Excavator Motors and handpieces Turbine Micromotor Handpiece Turbine Turbine 300.000 - 400.000 rpm Big force, les control, small torque Motors – micromotors Electromotors – maximum 40.000/min Air motors – maximum 20.000/min Gear to fast Gear to slow 1: 1 Blocked rotation Gear Blue coded handpiece 1:1 Gear Red coded handpiece 1:5 to fast Gear Green coded handpiece – to slow 2,7 :1 7,5 :1 Hendpieces contraangle straight Cutting instruments Burs Steel Tungsten carbide Diamonds Cutting instruments Power driven (powered) instruments for cutting - Rotary instruments Comon design characteristics shank neck Head (cutting part) Head (cutting part) neck shank fissure bur , round (ball) bur pear formed bur,, inverted cone bur Burs Cutting instruments – diamonds head shape • Ball, pear, cylinder,taper,flame, torpedo, lens and others….. Cutting instruments – diamonds Extra coarse – black Coarse – green Standard – blue or without any marker Fine - red Extra fine - yellow Ultrafine - white Diamonds • Blue –standard (90 – 120 mm) ISO 524 Universal Diamonds • Extra coarse (150 – 180 mm) ISO 544 • Cutting of crowns, old fillings Diamonds • Removal of old fillings, some preparations in prosthetic Diamanonds • Red fine ( 20 – 40 mm) ISO 514 • Finishing of borders of cavities Diamanonds • Extrafine (12 – 22mm) ISO 504, finifshig of composite fillings Diamonds Ultrafine – polishing of composite fillings (6-12 mm) ISO 494 Thank you!