1. picture outline is cone shape with base at DEJ and apex toward pulp
2. Zones of infected area: 1- Mild pulpal inflammation 2-Reparative dentine 3-Sclerotic dentine 4-Body of the lesion : deepest one "has pioneer bacteria cocci - beading" lateral distension of dentenial tubules - liquafiation foci - transverse cleft "
3. Pathology of Dental Caries in enamel
3.1. macroscopic
3.1.1. early : as opaque chalky white (white spot) may become rough to probe and later on cavitation occurs pit and fissure caries appears as opaque bordered zone related to fissure periphery and may be stained brown
3.2. radiographic picture
3.2.1. proximal surface caries appear as cone shaped radiolucent area in enamel with intact outer surface
3.3. microscopically
3.3.1. Findings of enamel caries are domstrated on longitudinal ground sections and have been examined by: Polarized light microscope determines percent of enamel pores by Ordinary light microscope
3.3.1.1. Microradiography: small x ray Film placed in contact with ground section and exposed to xray this microradiofraphy reflect the amount and distribution of minerals
3.3.1.1.1. Chemical analysis chemical structure is stuclied for seperate zones obtained by microdissection
3.4. 1.Translucent zone located on advancing front of lesion toward dentine it is the first observed changes histologically in early caries
3.4.1. 2.Dark Zone lies superficial to translucent zone by polarized light: increase in volume of pores, some small and some large
3.4.1.1. 3.Body of the lesion :it is the largest
3.4.1.1.1. 4. surface zone which may appear intact
3.5. Creación de webs
4. dentin caries
4.1. macroscopic
4.1.1. dentin is brownish and soft to probe
4.2. microscopic
4.2.1. 1-Initial uninfected lesion prior to cavitation of enamel) advancing front of enamel caries have reached dej but enamel surface is intact and no cavity formed
4.2.2. 2- infected lesion after bacterial invasion of enamel and formation of enamel cavity. dentinal tubules provide pathway for invasion of dentine by bacteria
5. factors contributing to caries
5.1. carbohydrates
5.1.1. importance
5.1.1.1. main compnent of diet that bacteria can act on and produce acid .
5.1.2. factors of cariogenecity
5.1.2.1. 1) types of cho :-Disaccharide: sucrose is arch criminal -polysaccharid : starch and collegen but less cariogenic
5.1.2.2. 2) amount of cho :increase intake of fermentable CHO so increase caries activity .
5.1.2.3. 3) texture of CHO :sticky cho is more cariogenic than solution one
5.1.3. vipeholm experiment
5.1.3.1. Aim: to investigate effect of total cho intake, frequency and texture on caries incidence.
5.1.3.2. diagram observation : eating sticky food as toffe and caramel between meals have highest caries activity .
5.1.3.3. conclusion :1- frequerency of adminstration of cho showed greater effect on caries activity .
5.2. microrganism
5.2.1. experiments
5.2.1.1. 1-miller experiment : proved that caries might be caused by action bacteria on fermentable carbs in un boiled test tube.
5.2.2. bacteria involved in caries
5.2.2.1. acidogenic :stept viridans group and lactobacilli
5.2.2.2. proteolytic : actinomyces, clostridia
5.2.2.3. strept mutans were found to be potent cariogenic specially in smooth surface of teeth
5.2.3. 3- proteolytic "chelation theory ": proteolytic bacteria +organic matrix = chelation agent deminerlizing enamel
5.2.4. theories
5.2.4.1. 1-acidogenic theory: acidogenic bacteria + carbs=lactic acid this acid deminerlizes inorganic part of enamel
5.2.4.2. 2- proteolytic theory : proteolytic bacteria act on organic matrix so produce sulpheric acid deminerlizing enamel
5.3. saliva
5.3.1. people with xerostomia have high caries activity