Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
summaries annual session White Spot Lesions Demineralization and Remineralization Presented by Eric Reynolds, AO, at the PCSO Annual Session, October 10, 2010. Summarized by Dr. Bruce P. Hawley, PCSO Bulletin Northern Region Editor. I n Dr. Eric Reynolds’ home country of Australia, the prevalence of dental caries is increasing in the 6- to 12-year-old child populations. Rather incredibly, oral disease has moved in recent years from the seventh to the second most expensive disease group in Australia, behind cardiovascular disease. This change appears to be related to increased consumption of flavored bottled beverages (resulting in a higher level of sugar consumption), as well as of bottled water, which does not include fluoride. Also, plasticizers in bottles may have a metabolic effect on the porosity of enamel. MECHANISM OF DENTAL CARIES Oral biofilms, which are really films of bacteria, take on a low pH when mature, and on enamel this becomes acidogenic. Glucose, fructose, and other fermentable carbohydrates in the diet can also lower the pH level, like sucrose. The white spot lesion is completely reversible in the initial stage, and of course our aim is to reverse the demineralization process whenever possible. White spot lesions can be detected in orthodontic patients as early as four weeks into orthodontic treatment. The inverse relationship between fluoride and caries is well known, and the conversion of hydroxyapatite to fluorapatite is desirable. Fluoride remineralizes predominantly at the tooth surface, but remineralization at the subsurface body of the demineralized lesion is needed to obtain general improvement. Net remineralization to form fluorapatite is believed to be calcium phosphate limited. The clinical application of calcium phosphate is not particularly successful due to a low solubility factor. Insoluble calcium phosphate is not easily applied or effectively located at the tooth surface. In studies going back to the 1940s and 50s, milk and cheese have been shown to cause anti- 34 cariogenic activity in animals and in situ caries models. The anticariogenic agents in milk have been identified as casein, calcium, and phosphate. REMINERALIZATION STUDIES The combination of casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP) is now marketed under the brand name Recaldent. CPP-ACP prevents caries in rat models, with 55% caries reduction at the 1% concentration level and 78% reduction at the 5% level. The inhibition of strep mutans’ in vitro adherence to the enamel surface by CPP-ACP has also been demonstrated. Several studies have been carried out in Australia comparing the use of sugar-free gum vs. sugar-free gum with CPP-ACP. In a randomized double-blind study of 12-yearolds in Melbourne, the experimental and control groups chewed their gum three times daily for a 24-month study period, with one of these daily sessions being supervised in the school setting. The gum with Recaldent showed a 53% increase of carious lesions, and the control group had a 20% decrease in lesions. This was true even in an environment of fluoridated water and fluoride toothpaste. CPP-ACP localizes calcium phosphate at the tooth surface and is still present three hours following the chewing session. In another randomized comparative mouthrinse study, the incorporation of fluoride into plaque via combined 2% CPP-ACP plus 1100ppm fluoride was better than with the fluoride only or the CPP-ACP alone, even under acid-challenged conditions. On a microscopic level, the defects do indeed get smaller, with acid-soluble apatite converting to fluorapatite. Intra- and inter-crystalline defects begin repairing, with preferential binding of the peptides to the faces of the hydroxapatite crystals. PCSO Bulletin • WINTER 2010 summaries annual session CLINICAL USE OF RECALDENT In Australia, Recaldent is available commercially as Tooth Mousse/MI, while in North America the only product with CPP-ACP is MI Paste (made by GC America). The esthetic improvement of demineralization requires the agent to get into the lesion. Dr. Reynolds likes first to remove the protein, which blocks ion diffusion. Rather than acid etching or microetching the tooth, he prefers bleaching with hypochlorite, though peroxide bleaching can also be done. Improvement often takes weeks or months to occur. There is enough clinical trial evidence to advocate short-term as well as long-term CPP-ACP use for caries prevention. Combined CPP-ACP with fluoride results in a greater regression of white spot lesions over a 12-week period than CPP-ACP alone or fluoride application alone (comparable to the mouth rinse study above). Subsurface remineralization is needed for post-orthodontic remineralization of white spot lesions. U.S.) can be used in the morning and evening, with the special CPP-ACP chewing gum after meals and snacks (this gum is not available in North America). Active demineralized lesions have a porous surface layer, which will show a rapid visual change to air drying. Inactive lesions, conversely, have a mineralized surface layer, and there is little to no change to air drying. In very severe cases of demineralization, the use of bleaching, acid etch, microabrasion, or strong acid application in the dental chair followed by the application of MI Paste can help to achieve an esthetic improvement. S It is possible to damage a demineralized area of enamel adjacent to a bonded orthodontic bracket while debracketing, and remineralization before bracket removal has been found to help reduce this damage in an in vitro study. During active treatment, Dr. Reynolds will have the atrisk patient apply the Recaldent agent with fingers around the wires and brackets before going to bed. During treatment or at deband, Tooth Mousse Plus (or MI Paste in the WINTER 2010 • PCSO Bulletin 35