牙体牙髓常见考点总结Presented by Kurtis.D in 2011Part 1, introduction of endodonticsPart 2, dental cariesDental caries: It is a bacteria infected disease and chronic, destructive process causing decalcification of the tooth hard tissue and leading to continued destruction of enamel, dentin or cementum, and cavitation of the tooth.Prevalence rate: It is the number of cases of a specific disease present in a given population at a certain time point.Incidence rate: It is the frequency of developing a particular disease during a given period of time; the numerator is the number of new cases during the specified time period and the denominator is the population at risk during the period.Dental plaque: It is unmineralized bacterial deposite that builds up on the teeth. It consists of adhesive matrix and bacteria. If not removed, it can lead to dental caries or periodontal diseases.Supragingival plaque: It is the dental plaque lies on the tooth surface above gingiva. It is the factor cause dental caries.Subgingival plaque: It is the dental plaque lies on the tooth surface below gingiva. It is the factor cause periodontal disease.Remineralizative therapy: It is a non-surgical treatment of dental caries. It is The reintroduction of complex mineral salts into enamel or cementum, to recover the hardness and arrest or reverse the early caries lesions. Pulpodentinal complex: The pulp and dentin is a biological complex. The nerve, blood vessel and cells can grow into the dentinal tubule and combine pulp and dentine together. When dentine is exposed, stimulation can affect pulp.Smear layer: When dentin is cut or prepared by dental instruments, the layer of debris is called the smear layer. This layer consists of broken-down collagen, hydroxyapatite and bacteria and varies in thickness from about 1-5 microns.Hybrid layer: It is the structure formed in dental hard tissues by demineralization of the surface and sub surface, followed by infiltration of monomers and subsequent polymerization.Resistance form: It is the shape given to a prepared cavity to enable the restoration and remaining tooth structure to withstand masticatory stress without fracture.Retention form: It is the shape or form of the conventional preparation that resist displacement or removal of the restoration from lateral or vertical forces.Pin-supported restoration: When tooth lesion is very serious but pulp is healthy, pin can be use to increase the retention of obturator. It is called pin-supported restoration.Pin-support retention: It is the retention by pin. Put the pins into the prepared tooth, then obdurate with restoration material. The obturator can acquire more retention.Sedating dressing: It is a treatment of deep caries by dressing the teeth with sedative materials so that the symptoms disappear. It is a temporary restoration with package such as zinc oxide.Properties of the cariogenic bacteria1. Main pathogen: Oral streptococci(streptococcus mutans/ streptococcus sanguinis/ streptococcus mitis ), lactobacillus, actinomyces2. These pathogens are acid production pathogen and acid tolerance3. Single type pathogen is hard to cause caries, dental caries is a multi-pathogen disease.Theory of etiology of dental caries1. Chemical theory2. Proteolytic theory3. Proteolysis-chelation theory4. Chemical-parasitic theory5. Four factor theoryDiagnostic method of dental caries1. Clinical signVisual: location, cavitationTactile: surface texture detecting2. Clinical symptoms3. Diagnostic testRadiographTransilluminationOptical methodThe principles of cavity preparation1. Remove all decayed dental tissuesThe decayed dental tissue can cause secondary caries. So it must be remove completely. The cleanness is according to the hardness and colour.2. Protect pulp vitality1) Interval preparation and water cooling2) Dont press pulp cavity3) Prevent accidental cavity access3. Save health dental tissues1) The extension of cavity should be least2) Dont use preventive extension4. Prepare resistance form and retention formThe adhesive mechanism of composite resin1. The resin can diffuse into the acid-etched dentin and form micro tugs. These tugs can provide physical lock retention.2. The surface treatment of dentin can advance the adhesion.3. The hybrid layer can advance adhesion.Indication of composite resin restoration1. Typecavity of anterior tooth. 2. Type cavity of anterior and posterior tooth3. Typeandcavity of posterior tooth suffering small occlusal force4. Restoration before crown restorationProcedure of composite resin restoration1. Colour selection2. Cavity preparation3. Basing and lining4. Surface treatment5. Put matrix band and wedge6. Fill resin7. Shaping The relationship between shape of obturator and periodontal tissue1. Correct shape of obturator can protect gingiva and prevent formation of dental plaque. Small ob