[Chewing gum and dental health. Literature review]

Clinical studies have demonstrated the caries promoting effects of sugar based gum when compared with non sugar chewing controls. Sucrose gum has been shown to stimulate plaque growth and increase its adhesivity. Acid produced in plaque and mixed saliva whilst chewing sugar gum is counteracted by the buffering action of mastication induced saliva. However the vast majority of studies measuring plaque pH has demonstrated acidification of plaque during use of sugar gum into the decalcifying zone (pH < or = 5.5), or after the gum is taken out. Sugar gum causes a more pronounced fall in plaque pH in individuals with an increased caries risk compared to the pH drop in more caries resistant individuals. Sorbitol, by itself or in combination with mannitol is slowly converted to acids by the plaque microorganisms. Chewing gums sweetened with these sugar alcohols do not cause a critical acidification of the plaque and appear not to promote caries in the clinical trial. Twelve weeks use of sorbitol chewing gum has been shown to induce a plaque more adapted to form acids from this sugar alcohol. This adaptation has been shown to persist for up to twelve weeks after cessation of the use of the sorbitol gum. Xylitol has generally been considered non-cariogenic because of its non-fermentability by most important plaque microorganisms. Plaque pH and pH of mixed saliva is increased during and following the use of xylitol based chewing gum. Prolonged use of xylitol or xylitol containing chewing gum reduces Streptococcus mutans counts in plaque and saliva, at the same time fostering remineralization of early caries lesions. Regular use of xylitol reduces the acidogenic potential of the plaque as well as its adhesiveness, at the same time increasing its mineral content. No adaptive changes in plaque metabolism resulting in the fermentation of xylitol have been reported, not even after long term, intense use. Xylitol chewing gum therefore is eminently suited to be used as part of a caries preventive regimen notably for high caries risk patients and those suffering from xerostomia. Adding mineral salts to sugar based chewing gum has been demonstrated to significantly inhibit caries development. Possible additional caries preventive benefits of mineral compounds added to sugar-free chewing gum have, so far not been reported. Sugar-free chewing gum has been shown to be an excellent vehicle for Fluoride. The plaque-growth retarding properties of Chlorhexidine-containing chewing gum have been shown to equal that of a Chlorhexidine mouthwash. Ureum added to a sugar-free chewing gum helps to neutralize plaque acids by liberating basic ammonia.