Continued Development of Therapeutic Dentifrices
The ongoing pressures of a competitive dentifrice market led to continued investigations to develop improved products, leading to changes in toothpaste formulations and packaging of products. Some examples include the development of gels vs. pastes, pumps to deliver the products, dual tube reservoirs, and the addition of many cosmetic agents as well. One of the early improvements was the development of "tartar control" toothpastes in the mid 1980s, which proved to be highly successful in the market place. A pyrophosphate or zinc additive was found to be effective in reducing the growth of tartar and not allowing it to harden into a deposit that was difficult to remove. This made cleanings easier for the hygienist during routine dental visits.45,46 Another tartar control agent made use of a co-polymer of ether and maleic acid (PVM/MA), in combination with pyrophosphate to reduce calculus formation. Not all people are troubled by excess tartar formation, but an increased public awareness of oral health has led to the addition of agents to not only clean the teeth and mouth but to improve overall oral health. Thus, manufacturers have focused on the development of “multi-benefit” formulations capable of addressing a combination of oral care needs. An example is the combination of fluoride and potassium nitrate to simultaneously control both caries and dentinal hypersensitivityy.47,48 We have also seen an increase in products that combine "cosmetic" and "therapeutic" agents into one. An example here would be the cleaning, tartar control, stain removal, or whitening ability of new formulations combined with fluoride to control caries.
Although fluoride dentifrices and improved oral health have greatly benefited the population by reducing caries incidence, surveys showed a continued high prevalence of gingivitis and gingival recession among adults.49 The desire to treat both caries and gingivitis, coupled with the changing patterns in oral health, led to extensive research by the Procter & Gamble laboratories and the "return" to stannous fluoride as an active ingredient. This required the development of a stabilized formulation that would provide sufficient stannous fluoride activity to provide the anti-gingivitis benefit and sufficient reserves of the active to provide a caries benefit. The stabilization system developed used sodium gluconate as a chelating agent to protect SnF2 from hydrolysis. Stannous chloride was also included as an anti-oxidant to protect SnF2 from oxidation and as a stannous reservoir to reduce the SnF2 loss onto the abrasive. The broad range of beneficial aspects of stannous fluoride, such as dentin desensitization, root surface reactivity, plaque and gingivitis benefits as well as its anticaries effectiveness strongly suggested that this unique active could be the basis for many future improvements in dentifrice formulations.50-60 Thus, the active agents most readily available in the US market once again included SnF2 as well as NaF and Na2FPO3. Unfortunately, the use of SnF2 continued to be limited at the time, largely due to poor taste, astringency, and potential for minor extrinsic stain. These challenges would take another decade to overcome.