牙体牙髓病学概论

Cariology Cariology and and EndodonticsEndodonticsA discipline to study the etiology,pathogenic mechanism,pathology,pathology-physiology,clinical expression,treatment and favorable turn etc.of the disease on dental hard tissue and pulp tissue.The content of the textbookCariology Non-cariogenic disease of dental hard tissue EndodonticsOperative dentistryHistoryIn 50s yearsOral medicinevCariologyvOperative dentistryvEndodonticsvNon-cariogenic disease of dental hard tissuevDisease of Oral mucosavPreventive dentistryvPeriodontologyvPaediatrics for dentistryStomatology in ancient timesBefore Christ(B.C.)There were some record about cariesImage liking character(script)worm +toothThe chinese were known to have treated dental ills with knife,cautery,and acupuncture,a technique whereby they punctured different areas of the body with a needle.In Dynasty Han(A.D.215282)There are some record about periodontologyAnno DominiPulpitisIn Han,Mr.Zhang Zhong Jing?Jin Gui Yao lue?was a very famous writings in which there was a record about arsenicArsenic is a toxicant medicine which has been generally used for killing pulp In Dynasty Tang(A.D.710 era)the people use silver paste to fill tooth decay In Tang,tooth brush with willow twig a toothbrush with hair planted was invented in A.D.911 century from a tomb of an emperors son-in-law of Liao from Chi Fong city3 events above describedreflected ancient civilization of our countryDentistry development in West countryThe first known dentist was an Egyptian named Hesi-re(3000 B.C.).He was chief toothist to the pharaohs,he was also a physician,indicating an association between medicine and dentistry.The GreeksHippocrates(500 B.C.)appreciated the importance of teeth.He accurately described the technique for reducing a fracture of the jaw and also replacing a dislocated mandible.He was familiar with extraction forceps for this is mentioned in one of his writings.Aristotle(384 B.C.)also stated figs and soft sweets produce decay.Galen(200A.D.Romans)was first to recognize that toothache could be:Pulpitis or pericementitisHe also classified teeth into centrals,cuspids and molars.B.Leonardo da Vinci(end of 15th Century)-he described the anatomy of the jaws,teeth and maxillary sinus.These drawings are the first to accurately describe the maxillary sinus.However,credit has been given to Dr.Nathaniel Highmore of England(1650).D.Leeuwenhoek(17th Century)-invented the microscope.He described the dental tubuli and was the first to see organisms of the mouth Anton van leeuwenhoekK.John Greenwood(1789)-dentures for George Washington were made by him.a red laser scansGeorge Washingtons false teeth not woodenLaser scans find gold,ivory,lead,human and animal teeth L.Pierre Fauchard(18th Century-1728)-Father of Scientific Dentistry.Wrote a great text Surgeon Dentist.He also wrote a complete work on Odontology in two volumes,843 pages.He recognized the intimate relationship between oral conditions and general health.He advocated the use of lead to fill cavities.He removed all decay and if the pulp was exposed,he used the cautery.Musee dArt Dentaire Pierre Fauchardat the Academie Nationale de Chirurgie Dentaire22 Rue Emile Menier,75116,Paris FranceHe prescribed oil of cloves and cinnamon for pulpitis.He described partial dentures and full dentures in his text.He constructed dentures with springs and used human teeth.Gold dowels were used in root canals filled with lead.He was also known as Father of Orthodontics.Fauchard died in 1768 at the age of 83.1763 A.DJohn Baker,M.D.Surgeon Dentist.The earliest qualified dentist to practice in Boston and in America.1836 A.D.Arsenic introduced for the killing of pulps,by Spooner.1840 A.D.The American Society of Dental Surgeons,first national dental organization.The Baltimore College of Dental Surgery,the first school in the world for the training of dentists was founded by Harris and Harden.Founded by Harris and Harden1859 A.D.Organization of American Dental Association on a representative basis.1890 W.D.Miller propose a chemical-bacteria Paraorganism theory to explain the mechanism of caries1891 A.D.Extension for prevention and scientific cavity preparation promulgated by G.V.Black.1892 A.D.The establishment of a three-year course in dental colleges.1906 A.D.Einhorn recommends novacaine and adrenalin combination for local anesthesia.1915 A.D.McKay and Black publish results of investigation of fluoride in drinking water.1956 A.D.Air-rotor drill,250,000 RPM Dr.Robert Borden.Stomatology in China before 1949 West China University(1910)Shanghai Second University(1920)4th Military Medical University(1935)Beijing University(1943)Shanghai Second UniversityWest China University 1918(School 1910)The first dental school in China was founded in West ChinaMedical University in 1917.A.W.LindsayA.W.Lindsay was teachingAfter 1949Hubei Medical College 1960 Founder Prof.Xia Liang Cai In recent 20 years,the science and techniques got great progressThere are 12 faculties or dental schools in each province Caries researchCaries VaccineEtiology&prevention Pulp diseaseModern root canal traitment Pulp biologyStem cell final targetAchievementsCraniofacial-oral-dental research in the century21stThe leadership team of NIDR initiated a strategic planning process in 1999 to identifyWhere we are(strengths,weaknesses,opportunities and threats)Where we want to go(e.g.,mission and vision)How we plan to get there(strategic plan)Several scientific areas will be concerned in century 21stFrom molecular biology to clinical investigations;etiology,pathogenesis,epidemiology,prevention,diagnosis and treatment of inherited craniofacial-oral-dental diseases and disorders.e.g.,ectodermic,dysplasia,cleft lip and palate,amelogenesis imperfect,dentin genesis imperfect,osteogenesis imperfect,and other inherited diseases.Inherited disease and disordersHereditary hypoplasiaHereditary aplasia of the enamel dental caries Periodontitis Oral candidiasis Herpes Hepatitis,HIV/AIDSInfections diseasesViral,bacterial,fungal and parasitic such asDiseased PeriodontiumPrimary herpetic stomatitisCandidal stomatitisNeoplastic diseaseSupports basic,patient oriented,and community-based research on the etiology,pathogenesis and metastasis,epidemiology,prevention,diagnosis,treatment of oral and pharyngeal neoplastic diseases Chronic disabling diseasesThe full range of research involving chronic disabling disease associated with the craniofacial-oral-dental complexThis includes osteoporosis,osteoarthritis and related bone disorders,temporo-mandible joint diseases and disorders,neuropathies and neuro-degenerative diseases including those involving oral sensory and motor functions and autoimmune diseases such as sjgrens syndrome.Chronic diseases of cran-oral-dental complex and other systemic diseases(e.g.,diabetes)Biomaterials,biomimetics and tissue engineering Biomaterials used for the repair,regeneration,restoration and reconstruction of craniofacial-oral-dental molecules,cells,tissues and organs The study of computer aid design(CAD)computer aid manufacture(CAM)for dentureBehavior,health promotion and environment aimed at assessing the interactive roles of sociological,behavior,economic,environmental,genetic,and biomedical factors in craniofacial-oral-dental diseases and disorders 1996 Diet and Oral HealthCariology is a discipline within Stomatology which deals with the complex interplaying between the oral fluids and the microbial deposits in relation to subsequent changes in the dental hard tissues.Several index have been used in dental caries Prevalence=No of the patients with caries No of the specific population in an area at risk of getting caries at that time Prevalence of caries:the total caries experience of a population in existence at a certain time in a designated area.Caries incidence is usually expressed as the number of new decayed teeth or surfaces per-a period in a individual,group,or population.Incidence of cariesDMF=Decayed teeth+Missing teeth+Filled teeth/Number of subjects examined DMFTvIf surface have been counted,then we refer to the score as DMF-SvIf the teeth have been counted,then it is refer to as DMF-TvThe DMF-S or DMF-T are often referred to as an“indexThe distribution of dental caries in oral cavityReducing tendency in developed country The DMFT prevalence of 12-year-old children in the Nordic countries in the period 1974-91.Denmark,Finland,Norway and Sweden seem to follow the same downward trend,whereas Iceland has started a more rapid decline somewhat later.Increasing tendency in developing country958498959892959813Romania China Fuji Tonga Jordanian45627883858662DMFTs for 12 Years-old in Part of developing countryThe caries prevalence of China Time Population people with caries prevalence Before 1949 32469 19258 59.3019501959 219312 106781 48.7019601969 544708 217774 40.0019701979 3766290 1356362 36.001983 131340 40.541984 permanent teethCities 25080Countryside 20636 29.70 Cities 19683 79.55Countryside 16253 58.48Deciduous teethThe DMFT prevalence of 12-year-old children in 11 provinces of ChinaBeijing 1.41 0.98Shanghai 1.17 0.95Tianjing 1.41 1.02Gansu 0.36 0.8Shandong 0.69 0.59Yunnan 0.46 0.88Liaoning 0.76 1.29Zhejiang 1.22 1.46Hubei 0.98 0.51Guangdong 0.91 1.65Sichuan 0.57 0.37Account 0.67 0.88 Province DMFT(1983)DMFT(1995)Age DMFT 12 1.03 15 1.42 18 1.60 3544 2.11 6574 2.49(DFT)The DMFT prevalence in 1995Current concept of caries etiologyDental caries is a multifactorial disease in which there is an interplay of three principal factors:the host(primarily the saliva and teeth),the microflora,and the substrate,or diet.A fourth factor time must be considered in any discussion of the etiology of caries.Diagrammatically,these factors can be portrayed as four overlapping circles.Micro-organismshost&toothSub-strateThe four circles diagrammatically represent the factors involved in the carious process.all four factors must act concurrently(overlapping of the circles)for caries to occurtimeno cariesno cariesno cariesno cariescariesCaries requires a susceptible host,a cariogenic oral flora and a suitable substrate that must be present for a sufficient length of timeSalivathe term saliva refers to the mixture of secretions in the oral carityvSaliva is produced day and night and it is constantly swallowed vSaliva is present as a proteinaceous film covering all surfaces of oral cavityThis mixture consists of fluids derived fromv the major salivary glandsv minor glands of oral mucosev traces from gingival exudateEffect of desalivation on incidence and extent caries in animals Effect of desalivation on caries in hamstersGruopNo.hamstersAvg.no.carious teethAvg.caries scoreIntact Salivary glands202.34.0Desalivated*1010.539.0*Parotid,submandibular,and sublingual glands.Decreased salivary flow and caries in humansvSarcoidosisvSjogrens syndromevTharapeutic radiationHydrogen ionBuffering abilityCalciumInorganic phosphateFluoricle Inorganic componentsOrganic componentsmucinsGlycoproteinsStatherin and acidic proline-rich proteinsamylaseAntrmicrobial proteinsSaliva and dental cariesthe quantity of saliva associated with caries experienceRelationship between salivary characteristics and caries prevalencePropertyRelationshipPropertyRelationshipFlow ratepHCa-Buffer capacity+PO4NH3AmylaseViscosityUrea-Salivary composition and cariesAntibacterial factors of glandular origin could protect oral mucosal and hard surfaces by helping to regulate the quantity and species distribution of oral microbesOral Microorganisms and dental plaqueIn contrast to mucosal surfaces,the surfaces of teeth are not constantly renewed by shedding of colonized epithelial cells.Surfaces of teethSome special sites occlusal fissues Approximal surfaceDental depositsBiofilms on dental surface-matrix-embedded microbial population,adherent to each other and/or to surface or interfacesAcquired pellicleAcellular,homogeneous organic film that forms on enamel and other hard surface by selective adsorption of salivary proteins.adsorption of salivary proteins or glycoproteinsOrigin Immediately after cleaning and polishing,salivary secrete deposit in the defects of enamel.v Surface pelliclev Subsurface pellicleHistological appearanceThe surface pellicle appears acellular and faintly granular under TEM Surface PelliclePellicles of unknown age may vary in thickness from 501000nm.globular fibrillar granular Different morphological typesA subsurface pellicleconsisting of dendritic processes that spread into the intercrystalline spaces and extend to 3m into the enamel.90%water 10%solid material compositionAccording to chemical analysesamino acids account for 45%to 50%carbohydrates amount 10%to 15%of the dry weight lipidFunctionvhealing,repairing,or protecting the enamel surfacevimparting selective permeability to the enamelvinfluencing the adherence of specific oral microorganisms to the tooth surfacevserving as a substrate or nutrient for the organismssummaryvOrganic depositvNaturally forms by selective adsorptionvOrigin of protein from salivavAfter polishing,reforms rapidlyvBacteria settle on the pellicle as soon as it forms vformation of dental plaqueDental Plaque In the fourth century B.C.Aristotle related soft,adhere food deposits to tooth decay,but it was not until the advent of the microscope in the seventeenth century that“animalcules(microorganism)were seen in these dental deposits.Anton van leeuwenhoek,a draper and sheriffs chamberlain in Delft recognized the limitation of mechanical oral hygiene in removing these deposits.Anton Van leeuwenhoek saw large numbers of living cells in scrapings from teeth:I judge from myself that all the people living in our united Netherlands are not as many as the living animalcules that I carry in my own mouth this very day.Terminology1847 Ficinus a slime coating denticulate1897 Williams demonstrated the presence of a mass of microorganisms 18981895 G.V.Black gelatinous microbial 1899 plaqueDental plaque Most figurative description:a bacterial aspic with millions of organisms standing shoulder to shoulder More formal definition by Le:plaque is the soft,non-mineralized,bacterial deposit which forms on teeth and dental prosthesis that are not adequately cleanedMorphology of dental plaque A white or off-white accumulation Variable thicknessThree main typies of organisms coccoid rod-shaped filamentous classificationvSupragingival plaque vSubgingival plaque vDental calculus(calcified plaque)Supragingival plaquevSmooth surface plaque vFissure plaque Supragingival smooth surface plaqueDivided into 4 areas:vplaque/tooth interfacevcondensed microbial layervbody of the plaque vplaque surfaceplaque/tooth interfaceIn some locations no pelicleHigher magnification of plaque-enamel border.Microorganisms that divide in horizontal planes are in direct contact with enamel(1 30,000).Condensed microbial layer a layer of very densely packed coccoid organisms,from 320 cells thickPart of a 7-day-old interdental plaque grown on enamel.The enamel matrix(bottom),appearing as a fine meshwork,is covered by a thin electron-dense and discontinuous pellicle.Immediately above this is the condensed microbial layer which is covered by a layer of coccoid and filamentous micro-organisms and probably Neisseria.The intermicrobial space is electron-lucent and reveals cell remnants(1 6,500).vBody of the plaque this occupies by far the largest portion of the plaque Thin section of plaque made of different bacterial species-predominantly coccoidal.Dense aggregation of microorganisms at the enamel surface(lower left)vPlaque surfacev loosely arrangement vGreat variety:coccoid,rod like,“corncobIn the surface layer of plaque some microorganisms co-aggregate with other species,as visualized by the presence of so-called corn cob structuresMagnified view of“corncobFree surface of plaque composed of unidentified organismsFree surface of plaque composed of coccoid gram-positive(heavily stained cell walls)and unidentified gram-negative microorganismsFissure plaque Gram-positive cocci and short rods predominate in a homogeneous,matrix,with occasional yeast cells Palisade and branching filaments are absent within the fissuresA:survey of dental plaque situated within a deep,narrow fissure of a premolarB:the upper half of the fissure is filled with dark material,the lower half is les dense C:Higher magnification reveals a plaque consisting of mostly ghostlike membrane and cell wall structures Subgingival plaque The matrix is sparse Organisms:filamentous organisms,bacilli,cocci,spirochetes Gram negative bacteriaThe filamentous nature of plaque associated with gingivitis.Note attachment of smaller bacteria to filamentsCalcified plaqueSupragingival calcucus white chalky yellowSub gingival calculus greenish blackDental calculus is plaque in which mineralization has involved both the plaque matrix and the microorganisms.Formation and development of dental plaques vUneven tooth surface vCarious lesions vill-filling margins of restorationsvIrregularities in positioning of the teeth the location favoring plaque formation:vPellicle formationvMicrobial colonization Process of formationPlaque formation can be considered as three phasesvInitial colonizationvRapid bacterial growthvRemodeling Bacteria are thought to be unspecifically associated with the tooth surface under the influence of Van der walls attractive forces as well as repulsive negative electrostatic forcesInitial microbial colonizationVan der walls forcesThere is a weakness forces between the molecules to be equal to 1/101/100 energe of chemical bondDepend on the cause and character of producing the forces:vOrientation forcevInduction force vDispersion forceOrientation forceInduction forceDispersion forceA firm attachment may subsequently be achieved by specific mechanismsLigands theoryRecognized system“adhesions receptorsSimplified explanation of the principle of selective adherence of bacteria to enamel.Successful attachment is achieved when the surface characteristics of a bacterium fit with a component in the pellicle(P)Two-reaction process for S.mutans initial weak attachment occurs between bacterial cell proteins and salivary glycoproteins of the acquired pellicle and is followed by cellular accumulation mediated by sucrose-dependent glucans and cell surface receptor ligands.The adherence of selected oral bacteria initially involves non specific,low-affinity,very rapid binding reactions followed by specific,high-affinity,slower,but stronger attachment to the acquired pellicle Microbial succession Receptors(oligossacharides)S.Oralis has a glactose-hinding adhesinActiuomyces viscosus proline rich proteinStatherin s.sangnis sialic acid Pioneer bacteria create an environment which is either more attractive for secondary invaders or increase unfavorable condition to themselves.In this way the resident microbial community is gradually replaced by other species In mature dental plaque there may be a subtle balance(homeostasis)that tends to eject invading species not previously present.Structural features of microbial colonization Initial microbial deposition after a cleaned tooth surface has been exposed for 4h to the oral environment,surprisingly few bacteria are found(one of reports)After 4 hours exposure the enamel is covered by pellicle which is a granular deposit,primarily located in Tomes processes pits(TP)and in perikymatal grooves(P)The first bacteria to colonize the tooth surface are of the cocco-bacillary type(B).note that the granular deposit does not cover the tooth surface in a uniform layer(PE)At this early stage bacteria are of the coccid or cocco-bacillary type and always reside in shallow depressions on the surface After 8h only a few smaller groups of microorganisms have settled on the surface sheltered by the perikymata Numerous bacteria spread across the surface as a monolayer In 12-h-old bacterial deposits the microorganisms spread in monolayer along the perikymata(P)In same areas multiplying microorganisms form multipl