Casein phosphopeptides (CPP), naturally found in milk, bind to oral surfaces and enhance enamel acid resistance while also increasing salivary fluoride levels.3 Amorphous calcium phosphate (ACP) is an active and soluble calcium phosphate compound that rapidly remineralizes enamel and dentin. When it forms in the enamel of the teeth and within the dentin and dentinal tubules, it creates a reservoir of remineralizing ions in the saliva. This helps with fluoride uptake and strengthens teeth.4 When dental tubules are filled with ACP, ACP is converted into tooth mineral. At the same time, ACP renews the mineral elements of the tooth, also increases the effectiveness of fluoride and reduces hypersensitivity by unclogging the dentinal tubules.5
MI Varnish became available in 2012, but third-party research into the development of Recaldent began in the 1980s.6 Reynolds and colleagues at the Melbourne School of Dentistry at the University of Melbourne investigated the casein protein in milk.7 They were able to isolate CPP – ACP complex from casein protein and recognition of its preventive properties, which led to the development of Recaldent. The FDA approved Recaldent in early 1999 and since then it has been used to protect teeth in products around the world.
CPP-ACP works by binding to the surface of the tooth as well as the bacteria in the plaque present on the surface of the tooth. Upon contact, a high concentration of ACP is deposited on the tooth surface. When exposed to acidic conditions, CPP-ACP acts as a buffer for free calcium and phosphate ions, significantly increasing calcium phosphate levels in plaque bacteria, thus inhibiting desalination and enhancing the remineralization process.
CPP-ACP is an excellent adjunct for controlling dental caries in moderate to high risk patients, reducing decalcification and enhancing remineralization in orthodontic patients, and reducing erosion in regurgitation patients. Some studies have shown a significant reduction in dry mouth as a result of CPP-ACP treatment.7 It has been observed that enamel remineralized by the application of CPP-ACP is more resistant to changes in pH.8.
Fighting caries around orthodontic brackets
The efficacy of fluoride varnish containing CPP-ACP in preventing caries around orthodontic brackets was tested using two fluoride varnishes: Duraphat and MI Varnish. Brackets were attached to 120 bovine incisors which were then subjected to pH cycling. The pH cycling protocol required neutral saliva at pH 7.0 for two hours, followed by deionized saliva at pH 4.5 for 22 hours. Optical coherence tomography was used to evaluate the enamel microstructure after pH cycling. The results showed that groups treated with MI Varnish had statistically less caries depth compared to Duraphat.8.
In another study, 33 orthodontic patients received MI Varnish on the day of bracket bonding, while 29 control group participants followed routine oral hygiene regimens. Participants were recalled at four weeks (twice) and then at three-month intervals. When patients were evaluated for the prevention of white spot formation, it was found that there was a small, but statistically significant, reduction in enamel decalcification index scores in the anterior zone of the MI Varnish group.9
Enamel demineralization during orthodontic treatment was also the subject of a double-blind study conducted by Robertson et al. in 2011, in which 60 routine orthodontic patients used either a topical dental cream containing fluoride and CPP-ACP (MI Paste Plus, GC America) or a placebo tray paste with fluoride for three to five minutes in the evening after brushing . Patients were followed up at four-weekly recall appointments for three months. Patients who used the fluoride cream and CPP-ACP had a 53.5% decrease in enamel decalcification index scores compared to the placebo group, which had scores that increased by 91.1% during the study.
The researchers concluded that application of fluoride and CPP-ACP prevented the development of new white spot lesions in orthodontic patients and reduced those already present on the gingival and incisal surfaces.10
Resistance to acid enamel
Forty primary incisors and 40 primary molars were obtained to evaluate the effectiveness of fluoride varnish with addition of CPP-ACP treatments on acid resistance. Groups for this study included: control (no treatment), MI Varnish, Clinpro White Varnish, and Colgate Duraphat Varnish. After the application of the fluoride varnish, the samples were stored in a humid environment for 24 hours. The varnish was then carefully removed and the specimens immersed in a pH 4.4 deionizing solution for six hours. They were then rinsed, dried and immersed in a remineralization solution with pH 7.0. Damage depth and microhardness were then analyzed by Tukey’s test and ANOVA (analysis of variance).
