Stannous fluoride treatment of acid-etched caries-like lesions of enamel: A scanning electron microscopic study

Author(s):  
M. John Hicks ◽  
Leon M. Silverstone ◽  
David G. Gantt ◽  
Catherine M. Flaitz

Although fluoride levels become elevated in sound enamel following a topical fluoride treatment, the caries-preventive effect of fluoride is thought to be due primarily to the role of fluoride in remineralization of clinically undetectable enamel lesions and hypomineralized enamel. During lesion formation, redistribution of fluoride from the enamel surface to the subsurface demineralized enamel occurs. This results in a surface zone with a relatively low fluoride content. In order to maintain an intact surface zone over a carious lesion, it may be necessary to replenish the fluoride levels with an exogenous fluoride source. By acid-etching the lesion surface, a more reactive surface is made available for fluoride interaction. In addition, porosities and etching patterns may be created, allowing for bonding of a caries-resistant resin material to the lesion surface. The purpose of this study was to determine the integrity of the caries-like lesion surface following acid-etching and subsequent stannous fluoride treatment (SnF2).

Author(s):  
Grace C.H. Yang

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.


2005 ◽  
Vol 29 (3) ◽  
pp. 215-219 ◽  
Author(s):  
Azza El-Housseiny ◽  
Aly Sharaf

Fissure sealant is an important tool in the prevention of dental caries. This study evaluated the effect of treating the enamel with topical fluoride gel prior to acid etching on sealant retention clinically (Part I) and in vitro (Part II). In part I a split mouth design using contralateral first permanent molars was conducted. Seventy (35 pairs) molars were sealed. Fissure sealant was applied on one side of the mouth (control group) and the contralateral tooth received acidulated phosphate fluoride gel (test group) prior to acid etching. The sealant was evaluated after 6 and 12 months and scored as intact, partially lost or completely missing. In part II, the shear bond strength between sealant and buccal enamel of extracted permanent molars without or with topical fluoride treatment was evaluated. Results showed no statistically significant differences between the test and control groups either clinically or in vitro. It is concluded that topical fluoride application prior to acid etching does not have a deleterious effect on sealant retention. However, further investigations should be conducted using different types of fluoride before altering the traditional practices.


2020 ◽  
Vol 8 (11) ◽  
pp. 991-1003
Author(s):  
Isha Bisla ◽  

Dental caries is a most common disease that affects large number of people. It is a worldwide public health problem, affecting numerous urban and rural communities. White-spot lesions (WSL) are the earliest macroscopic evidence of enamel caries. Typically, the enamel surface layer stays intact during subsurface demineralization, but, without treatment, will eventually collapse into a full cavity. Near-neutral pH of saliva is endowed with a natural buffering capacity. Natural demineralization of tooth at an early stage is reversed by saliva, which contains calcium ions, phosphate ions, buffering agents, fluoride, and other substances. The strategy for aided remineralisation is to have ions directly delivered to where and when they are needed the most. Several mechanisms are available for aided remineralisation. The most well known is the delivery of topical and systemic fluoride, which has been proven to be a highly effective measure for prevention of caries. However limitations and risks associated with the use of fluoride as a remineralising agent fuelled the need to develop newer non-toxic techniques that deliver calcium and phosphate ions directly into subsurface lesion and/or boost remineralising properties of saliva. Encouraging microscopic changes in the demineralized enamel surface following the treatment with different concentration of metal salts, involving zinc, strontium, magnesium, in addition to stannous fluoride, many metal salts are in use for the treatment of dental caries. Microscopic examination was conducted on teeth samples before and after pH-cycling procedure and following the treatment with the selected metal salt under polarized microscope (100X). The best obvious remineralisation was found following treatment with stannous fluoride, followed by zinc chloride. The stannous fluoride was the best in the remineralisation of initial caries, results for other metals seem to be promising if used for prevention of dental caries. Mineralization of teeth is determined by major inorganic elements as calcium, phosphorous in addition to other elements that occur in traces within tooth structure (Thylstrup and Fejerskov, 1996 Murry, 1996 Peter, 2004). Fluoride now a day is widely used either systemically or topically to increase resistance of teeth surface, it has been well documented as a major contributing factor in the decline of the incidence and severity of dental caries in many countries (Murry, 1996 Curzon,1999).So far fluoride has been considered to play an almost unique role in the prevention of dental caries however there is no reason to dismiss the role of other elements as being potential cariostatic agents. Different concentrations of different metal ions as zinc and copper have been tested for better effect on remineralisation in vitro (Dedhiya, et al., 1974 Fang et al., 1980). However controversy is present in the literature concerning their effectiveness in prevention of dental caries when used topically at effective concentrations (Torredo et al., 2004 Elzbieta et al., 2008 Curzon, 1983).


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