Physical, chemical, and histologic changes in dentin caries lesions of primary teeth induced by regular use of polyol chewing gums

Abstract

A previous clinical trial showed that long-term use of saliva-stimulating polyol (xylitol and sorbitol) chewing gums was associated with arrest of dental caries in young subjects. After a 20-22-month intervention (when the subjects were 8 years old), a total of 23 primary teeth with extensive dentin caries lesions whose surface in clinical examination was found to be totally rehardened (remineralized) could be removed because the teeth were near their physiologic exfoliation time. These teeth were subjected to histologic, microhardness, and electron microscopic tests. The majority of the specimens had been remineralized from the surface by a non-cellular-mediated process within the remaining collapsed, organic extracellular matrix associated with the remaining dentinal surface. Many of the underlying dentinal tubules were filled with a matrix that had been subsequently mineralized. Dental microanalyses showed that the topmost (outer) 20-microm-thick rehardened layer of the lesions exhibited the highest Ca:P ratio, which leveled off at a depth of approximately 150 microm. The rehardened surface layer (normally <0.1 mm in thickness) was significantly (P < 0.001) harder than sound dentin and nearly as hard as sound enamel. Although the main source of the mineral present in the rehardened layer was most likely of salivary origin, some extracellular remineralization was probably mediated by odontoblasts. The results complete the dinical diagnoses of the original trial and suggest that regular use of polyol chewing gums may induce changes in dentin caries lesions, which in histologic and physiochemical studies show typical characteristics of rehardening and mineralization.

Microhardness of dentine in primary teeth after topical fluoride applications

“…5,7 Others have suggested that dentin specimens be examined directly without ethanol dehydration. 3,6,15,16 Not only does the hardness of carious primary dentin differ (approximately 10-fold) when it is measured under hydrated and dehydrated conditions, but it is particularly higher in more-demineralized tissue. 17 Secondly, the load used in the microhardness test varied between studies, ranging from 1.5 gf (9.8 Â 10 À3 N) 6 to 500 gf (4.9 N).…”

“…4 Hardness testing is an indirect method of tracking changes in the mineral content of dentin, and several microhardness studies on dentin in arrested carious lesions have been published. 3,[5][6][7] Dentinal microhardness in those studies typically ranged in KHN from 25 to 65 (245 to 638 MPa). However, microhardness results from different studies cannot be compared directly.…”

“…Such dentin is usually microbiologically inactive and its hardness approaches that of sound dentin. 3 Because dentin with arrested caries is exposed to the oral cavity, it has a high fluoride content and becomes hypermineralized owing to continuous remineralization from oral fluids. The lesion in arrested caries has a brown-black pigmentation and is hard on clinical probing.…”

“…Measuring hardness has indeed been shown to be a reasonable method of examining the mineral content of teeth, 4 and several studies of caries or arrested caries have shown that changes in the microhardness of dentin is directly related to its mineral content. 3,[5][6][7] High-concentration topical fluoride agents, such as 5% sodium fluoride (NaF) varnish containing 22,600 ppm fluoride and 38% silver diamine fluoride (SDF) solution containing 44,800 ppm fluoride, have been used to arrest caries. Clinical trials have reported encouraging results after topical application of SDF solution or NaF varnish.…”

Purification and crystallization of xylitol from fermentation broth of corncob hydrolysates

“…Xylitol is used as an alternative sweetener to sucrose for diabetic patients because of its equivalent sweetening power but fewer calories [2], and is possibly even anticarcinogenic because it inhibits the growth of oral bacteria [3]. Due to these properties, xylitol is used as a sweetener in food products such as chewing gum, candy, soft drinks, and personal health products such as mouth wash and tooth paste.…”