As dentistry pivots toward caries management and away from "drill and fill," research is rolling in about the effectiveness of different treatments. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is used to remineralize, but just how well it works is still being established.
Now, researchers from China and New Zealand who sought to gauge its long-term effect on early caries in a systematic review have presented data in the Journal of Dentistry that can help guide clinicians' decision-making and patients' expectations (July 2014, Vol. 42:7, pp. 769-777).
"CPP-ACP has a long-term remineralizing effect on early caries lesions in comparison with placebo, although this does not appear to be significantly different from that of fluorides," the researchers from Nanjing University Medical School and Sichuan University in China and the University of Otago in New Zealand explained. "The evidence to support its synergistic effect with fluoride is insufficient based on the current existing long-term human randomized controlled trials."
That should temper the enthusiasm about remineralizing agents in which CPP-ACP is touted as supplement or enhancement to the fluoride they contain. But it is clear, at least, that CPP-ACP has a demonstrable remineralizing effect. Previous studies have shown that it stabilizes free calcium and phosphate ions and also binds well to plaque, the researchers noted.
Numerous studies also demonstrate CPP-ACP's anticariogenic effect via its ability to remineralize enamel subsurface lesions. The researchers were unconvinced by the data, however, because "the evidence regarding the in vivo remineralization effect of CPP-ACP remains insufficient due to the shortage of randomized controlled trials." That led them "to assess the long-term (>3 months) remineralizing effect of CPP-ACP on early caries lesions in vivo compared with placebo and/or fluorides."
To do so, they looked at randomized clinical trials involving generally healthy patients who had follow-up periods greater than three months. They were broadly inclusive of the mode of application; CPP-ACP could be topically applied through dentifrice, gum, mouth rinse, and tooth mousse.
The authors searched Medline via PubMed, Web of Science, Embase, Science Direct, Chinese Biological Medical, and the Cochrane Library for studies on the subject in English or Chinese that took place from 1970 to 2013. They screened the abstracts of 738 articles to determine their relevancy and retrieved, reviewed, and critically appraised 83 of them in their entirety. Eight of those studies met the inclusion criteria, six of which were randomized controlled trials, while the remaining two were controlled clinical trials. The studies involved 2,367 participants, most of whom were adolescents and the remainder children. The follow-up periods ranged from three to 24 months.
Three studies considered naturally occurring caries and found that CPP-ACP use resulted in a significant reduction in caries increment compared with a placebo. A chewing gum containing CPP-ACP also significantly enhanced the regression of approximal caries when it was compared with a placebo gum in a two-year follow-up study. "However, no clinical advantage was found for using extra CPP-ACP (10% w/w) after brushing with fluoridated toothpaste," they noted.
Similarly, CPP-ACP's effect on white-spot lesions (WSLs) associated with orthodontic treatment was examined in five studies, and no clinical advantage was observed when used as a supplement in fluoride toothpaste. While two trials did find that CPP-ACP helped to prevent WSLs, the researchers in those studies did not reveal whether the toothpaste tested contained fluoride.
That said, the researchers did not advise future studies to utilize nonfluoridated toothpaste since the participants would already have caries lesions to manage. They did recommend that future studies use more than one caries detection method, given their variable reliability for detecting early caries. In any event, more research is certainly needed.
"The present review has highlighted a lack of relevant research with low risk of bias on the effect of CPP-ACP on caries lesions, suggesting that CPP-ACP has a long-term (>3 months) remineralizing effect on early caries lesions in vivo compared with placebo," the researchers wrote. "But its synergistic effect with fluoride to restore early caries lesions still remains controversial."
