1	THEORIES OF DENTAL CARIES BY: DR. KHURRAM ZAFAR www.thedentalclinicpk.com
2	THEORIES OF DENTAL CARIES The Acidogenic theory The Proteolytic theory Proteolysis chelation theory
3	ACIDOGENIC THEORY W.D Miller was the first well known scientist and investigator of dental caries and published his results in 1882. According to him dental decay is a chemoparasitic process It is a two stage process there is decalcification of the enamel which also results in the destruction of the dentin. in the second stage there is dissolution of the softened residue of the enamel and dentin.
4	ACIDOGENIC THEORY In the first stage there is destruction is done by the acid attack where as the dissolution of the residue is carried by the proteolytic action of the bacteria's This whole process is supported by the presence of carbohydrates microorganisms and dental plaque
5	PROTEOLYTIC THEORY
6	PROTEOLYTIC THEORY The evidence given by the acidogenic theory was considerable but it was not conclusive, and alternative explanation was given in the form of proteolytic theory. Workers like “Heider, Bodecker (1878)and Abbott (1879) contributed considerably to this theory
7	PROTEOLYTIC THEORY There has been evidence that the organic portion of the tooth plays an important role in the development of dental caries The are some enamel structure which are made of the organic material such enamel lamelle and enamel rods These structure prove to be the path ways for the advancing microorganisms.
8	PROTEOLYTIC THEORY It has been established that enamel contains 0.56 % of organic matter of which 0.18% is keratin and 0.17 % is a soluble protein Microorganisms invade the enamel lamelle and the acid produced by the bacteria's causes damage to the organic pathways in advance The production of the yellowish pigment produced by the proteolytic bacteria’s the presence of this pigment was only possible in the presence of dietary carbohydrates.
9	PROTEOLYSIS CHELATION THEORY
10	PROTEOLYSIS CHELATION THEORY Some of the minor flaws of the acidogenic and the proteolytic theory were addressed in the proteolysis chelation theory. This theory was put forward by Schatz and his co-workers .
11	PROTEOLYSIS CHELATION THEORY CHELATION It is a process in which there is complexing of the metal ions to form complex substance through coordinate covalent bond which results in: poorly dissociated /or weakly ionized compound
12	PROTEOLYSIS CHELATION THEORY Example of chelation reaction: Hemoglobin in which 4 pyrrole nuclei are linked to iron by a similar bond Chelation is independent of the PH of the medium. The bacteria’s attack on the surface of the enamel this is initiated by keratinolytic microorganisms this result in the breakdown of the protein chiefly keratin and results in the formation of soluble chelates which decalcify enamel even at neutral PH Mucopolysaccarides may also act as secondary chelators.
13	Dental caries Its clinical correlation
14	TYPES OF DENTAL CARIES Gv blanks classification of caries class I , II , III , IV , V and VI Rampant caries Recurrent caries Arrested caries Root or cemental caries Baby bottle caries
15	Pits and fissure caries
16	Proximal caries
17	Cervical caries
18	Rampant caries
19	Recurrent caries
20	Arrested caries
21	Root or cemental caries
22	Nursing bottle caries