G V BLACK CLASSIFICATION In the first decade of the twentieth century an American dentist and teacher, G. V. Black, established principles governing the design of cavities and suggested steps in their preparation. He based these principles on what was known at the time about the natural history of caries and the restorative materials available. The wisdom of his work was such that it remained virtually unchallenged for more than half a century. Now, with new materials, a better understanding of caries, and research findings into the success or otherwise of various restorative procedures, the principles have been largely revised.
G. V. Black was a far-sighted scientist who would surely have expected that his ideas would have been taken up, researched, and revised by successive generations of clinicians and scientists. It would perhaps have been a disappointment to him that this was not done until relatively recently, but he would undoubtedly have been the first to applaud these developments. In 1908 Dr Black wrote: ‘the complete divorcement of dental practice from studies of the pathology of dental caries, that existed in the past, is an anomaly in science that should not continue. It has the apparent tendency plainly to make dentists mechanics only.’ Since his principles have now been so extensively
modified, and since many conditions in addition to caries are treated operatively (see Chapter 1), no further reference will be made to Black’s principles.
Black also described a classification of carious lesions which is still widely used in dental schools. However, this classification is now regarded as incomplete in that it does not include root caries and secondary caries. Also, it does not include non-carious lesions, which are treated in the same way as carious lesions. Therefore this classification is not used in this book but it is useful clinical shorthand and is as follows:
Class I. Caries affecting pits and fissures.
Class II. Caries affecting the approximal surfaces of posterior teeth.
Class III. Caries affecting the approximal surfaces of anterior teeth
Class IV. Caries affecting the approximal surfaces of anterior teeth and involving the incisal angle.
Class V. Caries affecting the cervical surfaces
Why restore teeth?
The objectives of restoring teeth are as follows:
• to restore the integrity of the tooth surface
• to restore the function of the tooth
• to restore the appearance of the tooth
• to remove diseased tissue as necessary
Dental caries, Dental caries is a process which may take place on any tooth surface in the oral cavity where a microbial biofilm (dental plaque) is allowed to develop for a period of time. Although there are some 300 bacterial species in dental plaque, it is not a haphazard collection of micro-organisms. It is an ordered accumulation forming a community with a collective physiology. The bacteria in the biofilm are always metabolically active, causing minute fluctuations in pH. These may cause a net loss of mineral from the tooth when the pH is dropping. This is called demineralization. Alternatively there may be a net gain of mineral when the pH is increasing. This is called remineralization. The cumulative result of these de- and remineralization processes may be a net loss of mineral and a carious lesion which can be seen. Alternatively the changes may be so slight that a carious lesion never becomes apparent.
The carious process is the metabolic activity in the biofilm. This is an ubiquitous, natural process because the formation of the biofilm and its metabolic activity cannot be prevented. However, disease progression can be controlled so that a clinically visible enamel lesion never forms. The deand remineralization processes can be modified particularly by regular disturbance of the biofilm with a toothbrush and fluoride toothpaste. If the biofilm is partially or totally removed mineral loss may be stopped or even reversed towards mineral gain. The fluoride in the toothpaste delays lesion progression by inhibiting demineralization and encouraging remineralization.
G V BLACK CLASSIFICATION
G V Black Classification of dental caries is the standard method used in identification and classification of carious lesions according to its location on the tooth surface. G.V. Black have only give five classifications, but a sixth one was later added make six classification of dental caries. These classifications are used when examining patient and then recording on the patient’s chart the type of caries found on the teeth.
CLASS I LESIONS: All pit-and-fissure restorations are Class I, and they involve the following 3 location groups:
- The occlusal surfaces of molars and premolars
- The occlusal two thirds of the buccal and lingual surfaces of molars
- The lingual surfaces of anterior teeth
CLASS II LESIONS: Involve the proximal surfaces (mesial and distal) of posterior teeth with access established from the occlusal tooth surface
CLASS III LESIONS: Involve the proximal surfaces of the anterior teeth which may or may not involve the lingual extension but DO NOT involve the incisal line angle.
CLASS IV LESIONS: Involve all proximal surfaces of anterior teeth which also INVOLVE the incisal line angle.
CLASS V LESIONS: Involve the CERVICAL THIRD of all teeth, including the proximal surface of posterior teeth where the marginal ridge is not included in the cavity preparation (Do not involve pit & fissure areas)
CLASS VI LESIONS: Involve the incisal edges of all anterior teeth and the cusp tips of all posterior teeth.