MI Paste Plus is a professional-grade dental cream designed to strengthen and remineralize tooth enamel. Made by GC America, it combines two active components: a calcium-phosphate complex derived from milk protein and 900 ppm fluoride (0.2% sodium fluoride). It’s not a toothpaste replacement. Instead, you apply it after brushing as a targeted treatment for weakened or damaged enamel.
How MI Paste Plus Works
The key ingredient is something called CPP-ACP, short for casein phosphopeptide-amorphous calcium phosphate. In plain terms, it’s a cluster of calcium and phosphate ions stabilized by a protein found in cow’s milk. When you apply the paste to your teeth, these clusters settle into dental plaque and onto enamel surfaces, flooding the area with the same minerals your teeth are made of. This creates a mineral-rich environment around the tooth that helps reverse early damage from acid attacks, the kind that happen every time you eat or drink something acidic or sugary.
The fluoride in MI Paste Plus works alongside the calcium and phosphate rather than independently. Fluoride gets incorporated into the surface of enamel crystals, making them harder and more resistant to acid. At the same time, the calcium and phosphate from the CPP-ACP complex actually enhance fluoride uptake, meaning the enamel absorbs more fluoride than it would from fluoride alone. The combination also buffers plaque pH, helping neutralize the acids that bacteria produce. This two-pronged approach, rebuilding lost minerals while making enamel more acid-resistant, is what sets it apart from standard fluoride toothpaste.
What It’s Used For
MI Paste Plus is most commonly recommended for white spot lesions, those chalky white patches that appear on teeth when minerals have been lost from the enamel surface. These are especially common after braces come off. A clinical trial published in the Dental Research Journal found that MI Paste Plus was effective at reducing the size of post-orthodontic white spots, increasing mineral content in the affected areas, and improving the overall appearance of the enamel.
Beyond orthodontic aftercare, dentists recommend it for several other situations:
- Tooth sensitivity caused by exposed or weakened enamel
- Early-stage cavities that haven’t yet broken through the enamel surface
- Dry mouth from medications or medical conditions, where reduced saliva leaves teeth more vulnerable to decay
- Post-whitening sensitivity, since bleaching treatments can temporarily weaken enamel
- High cavity risk in patients who need extra mineral support beyond regular toothpaste
It’s worth noting that MI Paste Plus works on early, pre-cavity damage. Once a cavity has fully formed and broken through the enamel, no topical paste can reverse it.
MI Paste vs. MI Paste Plus
GC America makes two versions. The original MI Paste contains only CPP-ACP with no fluoride. MI Paste Plus adds 900 ppm of fluoride. The fluoride-free version is sometimes preferred for very young children who might swallow the paste, or for people who want to avoid fluoride for personal reasons. For most adults and older children, MI Paste Plus is the stronger option because of the synergistic effect between fluoride and CPP-ACP. The fluoride doesn’t just add a separate layer of protection; it actually makes the calcium-phosphate complex more effective at rebuilding enamel.
How to Apply It
MI Paste Plus is applied after your normal brushing routine, not as a substitute for toothpaste. The recommended process for adults and children over 12: brush your teeth as usual, rinse your mouth, then squeeze a pea-sized amount onto a clean finger. Spread an even layer over your upper teeth, then repeat for the lower teeth. Leave the paste on for a minimum of three minutes and don’t rinse afterward. The longer the paste stays in contact with your teeth, the more mineral absorption occurs. Some dentists recommend leaving it on for longer or applying it with a custom tray for more targeted coverage.
MI Paste Plus comes in five flavors: melon, mint, strawberry, tutti frutti, and vanilla. Each tube is 40 grams.
Who Should Not Use It
Because the active ingredient is derived from casein, a milk protein, MI Paste Plus is not safe for anyone with a milk protein allergy. This is a true contraindication, not a general precaution. The product label also warns against use for people with a hydroxybenzoates allergy, which relates to the preservatives in the formula. If you experience any allergic reaction, stop using it, rinse your mouth with water, and seek medical attention.
Where to Get It
MI Paste Plus is widely available through dental offices and online retailers. While it contains a prescription-level fluoride concentration (0.2% sodium fluoride), it can often be purchased without a prescription depending on where you shop. Many dentists sell it directly or recommend a specific source. A single tube typically lasts several weeks with daily use, though cost and duration vary depending on how much you apply and whether you’re treating your full mouth or specific areas.