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Cariology and Endodontics A 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 textbook Cariology Non-cariogenic disease of dental hard tissue Endodontics Operative dentistry History In 50s years Oral medicine vCariology vOperative dentistry vEndodontics vNon-cariogenic disease of dental hard tissue vDisease of Oral mucosa vPreventive dentistry vPeriodontology vPaediatrics for dentistry Stomatology in ancient times Before Christ (B.C.) There were some record about caries Image liking character (script) worm + tooth The 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 periodontology Anno Domini Pulpitis In Han, Mr. Zhang Zhong Jing Jin Gui Yao luewas a very famous writings in which there was a record about arsenicarsenic Arsenic is a toxicant medicine which has been generally used for killing pulp In Dynasty Tang (A.D.710 era) the people use silver paste silver paste to fill tooth decay In Tang, tooth brush with willow twigtooth 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 city 3 events above described reflected ancient civilization of our country Dentistry development in West country The 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 Greeks Hippocrates (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 pericementitis He also classified teeth into centrals, cuspids and molars. B. Leonardo B. Leonardo dada Vinci Vinci (end of (end of 15th Century) - he 15th Century) - he described the anatomy described the anatomy of the jaws, teeth and of the jaws, teeth and maxillary sinus. These maxillary sinus. These drawings are the first drawings are the first to accurately describe to accurately describe the maxillary sinus. the maxillary sinus. However, credit has However, credit has been given to Dr. been given to Dr. Nathaniel Highmore of Nathaniel Highmore of England (1650).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 leeuwenhoek K. John Greenwood (1789) - dentures for George Washington were made by him. a red laser scans George Washingtons false teeth not wooden Laser 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 Fauchard at the Academie Nationale de Chirurgie Dentaire 22 Rue Emile Menier, 75116, Paris France He 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.D John 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 Harden 1859 A.D.1859 A.D. Organization of American Dental Organization of American Dental Association on a representative basis.Association on a representative basis. 18901890 W.D. MillerW.D. Miller propose a chemical-bacteria Paraorganism theory to explain the mechanism of caries 1891 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 University West China University 1918(School 1910) The first dental school in China was founded in West China Medical University in 1917. A.W. Lindsay A. W. Lindsay was teaching After 1949 Hubei Medical College 1960 Founder Prof. Xia Liang Cai In recent 20 years, the science and techniques got great progress There are 12 faculties or dental schools in each province Caries research Caries Vaccine Etiology 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 disorders Hereditary hypoplasia Hereditary aplasia of the enamel dental caries Periodontitis Oral candidiasis Herpes Hepatitis,HIV/AIDS Infections diseases Viral, bacterial, fungal and parasitic such as Diseased Periodontium Primary herpetic stomatitis Candidal stomatitis Neoplastic disease Supports 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 diseases The full range of research involving chronic disabling disease associated with the craniofacial-oral-dental complex This 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 denture Behavior, 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 Health Cariology 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 caries DMF=Decayed teeth+Missing teeth+Filled teeth/Number of subjects examined DMFT vIf surface have been counted, then we refer to the score as DMF-S vIf the teeth have been counted, then it is refer to as DMF-T The DMF-S or DMF-T are often referred to as an “index” The distribution of dental caries in oral cavity Reducing 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 country 95 84 98 95 98 92 95 98 1 3 Romania China Fuji Tonga Jordanian 4 5 6 2 7 8 83 8586 62 DMFTs for 12 Years-old in Part of developing country The caries prevalence of China Time Population people with caries prevalence Before 1949 32469 19258 59.30 19501959 219312 106781 48.70 19601969 544708 217774 40.00 19701979 3766290 1356362 36.00 1983 131340 40.54 permanent teeth Cities 25080 Countryside 20636 29.70 Cities 19683 79.55 Countryside 16253 58.48 Deciduous teeth The DMFT prevalence of 12-year-old children in 11 provinces of China Beijing 1.41 0.98 Shanghai 1.17 0.95 Tianjing 1.41 1.02 Gansu 0.36 0.8 Shandong 0.69 0.59 Yunnan 0.46 0.88 Liaoning 0.76 1.29 Zhejiang 1.22 1.46 Hubei 0.98 0.51 Guangdong 0.91 1.65 Sichuan 0.57 0.37 Account 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 1995 Current concept of caries etiology Dental 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- organisms host The agent must be isolated from the host and grown in a lab dish; The disease must be reproduced when a pure culture of the agent is inoculated into a healthy susceptible host; The same agent must be recovered again from the experimentally infected host Kochs postulates Specific bacteria and caries Lactobacilli these bacteria were thought to play an important role in caries etiology when it was first found that early carious plaque contained elevated levels of lactobacilli compared with plaque from non-carious surfaces Lactobacill Caries free group: 100/ml Caries active group: 100000/ml In a group of caries-free children the mean number of lactobacilli per 1ml of saliva was in the hundreds, while in caries active children the mean number per1ml was in the range of 100,000. The early observation on changes in lactobacillus levels in the oral cavity led many dental scientists to consider these bacteria as the specific microbial etiological factor in human caries For a number of reasons, the lactobacilli failed to qualify as an exclusive etiological agent in human caries formation: The affinity of lactobacilli for tooth surface is low, 0.01% High levels of lactobacilli tend to exist after caries has developed, caries can frequently be initiated in the absence of detectable lactobacilli. The lactobacilli are secondary invaders, they may contribute to the progression of decay due to their acidogenic and aciduric properties Conclusion Streptococci In vitro studies with the oral streptococci have demonstrated many features that support their role as cariogenic agents vRelatively rapid generation vTo produce large quantities of acid vAciduric vTo utilize a wide range of fermentable carbohydrates vTo produce extracellular polysaccharides vTo store intracellular carbohydrate vTo form plaque matrix Streptococcus mutans In the early 1920s, Clark attempted to evaluate the etiology of caries by analyzing the microbial content of plaque from human carious lesions A streptococcal bacterium was consistently isolated from the samples and its pleomorphic nature (range from cocci to rods, depending on the culture conditions) caused it to be named Streptococcus mutans Orland etc. demonstrated that microorganisms were required for imitation of dental caries in rats In 1960s at the NIDR got a series of success Keyes and Fitzgerald showed that in rats, caries is an infectious and transmissible disease, and that specific streptococci from carious lesion in animals could induce extensive decay in hamsters. S.mutans and Human caries S.mutans represents less than 1% the flora in pooled plaque from caries-inactive individuals S.mutans normally makes up 5% to 10% of the total bacteria present in pooled plaque samples obtained from caries-active subjects High concentrations of S. mutans is found mainly at retentive sites such as caries lesions, occlusal surface, pits and fissures, and approximal areas A series studies indicate that S.mutans is significant involved in occlusal fissure decay S.mutans and sucrose One of the more unique features of S.mutans is the ability to utilize dietary sucrose to enhance colonization of the oral cavity S. mutans has the ability to metabolize the disaccharide sucrose by several pathways Two extracellular sucrose-dependent polysaccharide-forming enzymes are constitutively produced and excreted from the cell by S.mutans Dextransucrase or glucosyltransferase(GTF) is the enzyme responsible for glucan production. When glucan is formed by GTF, the products contain varying proportions of (16) and (1 3) linkage The (1 3) linkage are critically important in that as their proportion increases the glucan becomes less soluble in water Classification of mutans streptococci Other cariogenic bacteria Bacteria capable of producing carious lesions at different sites in the dentition of germ-free rats site Bacterium Smooth occlusal Root Surfaces Fissures Surfaces Lactobacillus acidophlilus - + - Lactobacillus casei - + - Streptococcus mutans+ + + Streptococcus sanguis - + - Streptococcus salivarius+ + - Streptococcus mitior - + - Streptococcus milleri+ + - Streptococcus faecalis - + - Actinomyces viscosus - + - Actinomyces naeslundii - + + Actinomyces israelii - + + Rothia sp. - - + The Actinomyces species and other gram positive rods may be involved in the initiation of lesions on root surfaces of human teeth Members of the genus veillonella are obligate anaerobes and are found in significant numbers in dental plaque and saliva Within plaque these bacteria have the capacity to utilize lactic acid and convert it to less harmful products The progress on bioflms research Our understanding of biofilms has been advanced over last decade by the application of novel techniques. These include non-invasive and non-destructive microscopic techniques (e.g. scanning confocal laser microscopy) That biofilms are usually lightly structured with channels traversing the depth of biofilm, creating primitive circulatory system. What is the significance of biofilms Gene expression can alter markedly when cell form a biofilm, resulting in many organisms having a radically different phenotype following attachment to a surface. DNA microarrays have show that 73 genes and 50% of the detectable proteome were differentially regulated in biofilms of P.aeruginosa when compared with conventional liquid grown (planktonic) cell. Cell-cell communication Gram-positive bacteria generally communicate via small diffusible peptides Gram-negative bacteria secrete acyl homoserine lactones (AHLS) The MIC of an organism growing on a surface can range from two-to 1000-fold greater than the same cells grown planktonically What is the significance of microbial communities The component organisms are not merely passive neighbors but rather that they are involved in wide range of physical, metabolic and molecular interactions. This community life-style provides enormous potential benefits to the participating organisms vA broader habitat range for growth vAn increased metabolic deversity and efficiency vAn enhanced resistanc to environmental stress Horizontal gene transfer is also more feasible in multi- species biofilms Plaque structure Confocal laser scanning microscopy has revealed that supergingival plaque can have a structured architecture. Polymer-containing channels or pores have been observed that link the plaque/oral environment interface. Typical vertical (xz) section through a four-day human plaque sample taken in reflected-light mode. Images were taken at 0.6-umintervals from the top of the biofilm to the enamel surface underlying it. The image clearly demonstrates the bacterial aggregates (grey-white) separated by areas of low reflectance (arrowed) presumed to be channels. Inverted biomass (M) and associated narrow attachment points (A) can also be observed. Scale bar = 25 um That bacterial vitality varies throughout the biofilm, with the most viable bacteria present in the central part