CLEANING EFFECTIVENESS OF DENTIFRICES

T OST persons who are conscious of their teeth would like to have them free lVI from dingy films or deposits. It is not only believed that such tooth sur-faces look better, but that they give out less odor. ' It is also known that most gingivitis is caused by local irritation and that accumulations on the teeth brought about by faulty oral hygiene constitute the greatest source of local irritation. The part that the dentifrice actually plays as an adjunct to the toothbrush in this matter of appearance and the maintenance of oral hygiene has only been partially determined.' Phillips6 studied the abrasiveness of dentifrices and the resulting effect on tooth luster. This study showed that smooth, lustrous tooth surfaces were pro-duced by a sodium metaphosphate type of dentifrice. Phillips also showed that this smoothness of surface might be brought about with no appreciable abrasive effect on enamel and with the development of a minimum amount of erosion of exposed cervical dentin. Later Phillips ' showed that surfaces of extracted teeth with a high luster accumulated fewer bacteria from contact than did surfaces with a low degree of luster. Several serious attempts have been made to study the deposits usually found on teeth. These opinions and findings have been carefully summarized bv Vallotton.8 There are of course several different types of unsightly tooth sur-face accumulations recognized today. Exactly what these stains are, how they form, how they attach themselves to the teeth, and how they may be prevented from forming are questions not yet answered. Until these points are better understood, it is our opinion that there will be a need for a better method of comparing tooth cleanliness so that the effectiveness of dentifrices, brushes, and techniques can be properly evaluated. It is, therefore, the purpose of this study to compare the cleansing effect of various dentifrices upon the visible surfaces of the teeth. This has been accomplished by having dental students brush their teeth for three weeks each with several different dentifrices. Kodachrome photo-ngraphic records are used to estimate the comparative effectiveness of the denti-frices. Comparisons are made on the basis of the differences in cleanliness of the tooth surfaces visible to the naked eye