Clinical evaluation of diamine silver fluoride/potassium iodide as a dentine desensitizing agent. A pilot study.

BACKGROUND: The aim of the present study was to compare the efficacy of an experimental diamine silver fluoride/potassium iodide product with an oxalic acid-based preparation in reducing dentine hypersensitivity. METHODS: The study was conducted as a double-blind, randomized clinical trial. A total of 19 subjects with dentine hypersensitivity on both sides of their upper arch were selected. The most sensitive tooth in each quadrant was identified and received a cold stimulus. The response was recorded on a visual analogue scale (VAS). The tooth thus selected was treated with one of the treatment agents. One week later the level of dentine sensitivity was assessed. Participants were also asked for their subjective assessment of treatment effects. RESULTS: The mean difference between VAS at baseline and seven days for teeth treated with diamine silver fluoride/potassium iodide was greater than that for teeth treated with the oxalic acid-based preparation (p = 0.0134). The subjects' subjective assessment of changes in dentine hypersensitivity indicated that more obtained relief with the diamine silver fluoride/potassium iodide treatment (p = 0.0129). CONCLUSIONS: It was concluded that an experimental diamine silver fluoride/potassium iodide product has potential as a treatment for dentine hypersensitivity.

The inability of Streptococcus mutans and Lactobacillus acidophilus to form a biofilm in vitro on dentine pretreated with ozone.

BACKGROUND: The use of ozone therapy in the treatment of dental caries is equivocal. The aim of this study was to use an in vitro model to determine the effects of prior ozone application to dentine on biofilm formation and to measure any associated reduction in bacteria viability. METHODS: Twenty dentine discs were bonded to the bases of 5 mL polycarbonate screw top vials. Ten dentine discs were infused with ozone for 40 seconds, 10 samples remained untreated as a control. The vials were filled with nutrient medium, sterilized and placed into the outflow from a continuous chemostat culture of Streptococcus mutans and Lactobacillus acidophilus for four weeks. At the conclusion of the experiment bacterial growth was monitored by taking optical density readings of the growth medium in each vial and the outer surface of the dentine specimens were examined by scanning electron microscopy as shown by SEM analysis. RESULTS: Ozone infusion prevented biofilm formation on all the treated samples while there was substantial biofilm present on the control specimens. While the average optical density of the control specimens was almost twice that of the ozone infused dentine (0.710 for the control with a SD of 0.288 and 0.446 for the ozonated samples with a SD of 0.371), the results were not significant (p > 0.05). CONCLUSIONS: This preliminary study has shown that the infusion of ozone into non-carious dentine prevented biofilm formation in vitro from S. mutans and L. acidophilus over a four-week period. The possibility exists that ozone treatment may alter the surface wettability of dentine through reaction with organic constituents.

An in vitro investigation of marginal dentine caries abutting composite resin and glass ionomer cement restorations.

BACKGROUND: There are a number of studies citing the primary reason for replacing auto cure glass ionomer cements was due to recurrent caries. The purpose of this study was to use an in vitro model to measure caries at the dentine restoration interface of bonded composite resin and auto cure glass ionomer cement restorations and to measure the amount of surface degradation occurring in the restorative materials. METHODS: Specimens of auto cure glass ionomer cements (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and bonded composite resin restorations (Ice, SDI) were placed separately at the dentino-enamel junction of 10 recently extracted human third molar teeth, disinfected and placed into the overflow from a continuous culture of S. mutans for two weeks. Restorations were sectioned and prepared for scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Restoration tooth interfaces were photographed and the distance from the surface of the teeth to the surface of the restorations measured. EPMA of percentage weights of calcium, phosphorous and fluoride were made outwards from the restoration surface 130pm at a depth of 10 microm below the surface of the dentine. RESULTS: There were significant differences between the surface heights of composite resin, auto cure glass ionomer cements compared to teeth surfaces. Percentage weights of calcium and phosphorus levels were similar to non-demineralized dentine in the auto cure glass ionomer cement samples but there were significant reductions in mineral content of dentine adjacent to bonded composite resin restorations. Fluoride levels were mixed. CONCLUSIONS: This study shows that placing a bonded composite resin restoration into dentine affords little protection to the surrounding tooth from caries attack although insignificant degradation of the restorative surface occurs. Placing a glass ionomer cement restoration into dentine protects the surrounding tooth from caries but degradation of the restoration surface occurs.

Electron probe microanalysis of ion exchange of selected elements between dentine and adhesive restorative materials.

BACKGROUND: There have been numerous attempts to demonstrate the phenomenon of ion exchange between auto cure glass ionomer cements (GICs) and dentine. The purpose of this study was to employ an electron probe microanalysis (EPMA) technique to examine the interchange of elements between non-demineralized dentine and two types of restorative material, auto cure GICs and a resin composite. METHODS: Restorations of auto cure GICs (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and a bonded composite resin were placed in each of 10 recently extracted human third molar teeth. After two weeks the restorations were sectioned and prepared for EPMA. Percentage weights of calcium, phosphorus aluminum, strontium and fluoride were calculated in the restorations 200 microm from the restorative interface and 200 microm into the dentine at 5 microm intervals. RESULTS: There was evidence of calcium and phosphorus in all five auto cure GICs to a depth of 50 microm. Aluminum and strontium ions were also present in dentine except subjacent to Ketac Molar restorations. There was evidence of element transfer into composite resin and resin-bonded dentine. CONCLUSIONS: The findings of this paper support the concept of ion exchange as a bonding mechanism between auto cure GIC and dentine. Element penetration into tooth structure and GIC exceeded beyond the "ion exchange layer" observed in scanning electron microscopy studies. Penetration of calcium and phosphorus into composite resin from dentine likely occurred as a result of the self-etching process dissolving calcium and phosphorus and incorporating these elements into the hybrid layer. The presence of Al and Sr ions in dentine were likely to be associated with resin tags extending into the dentine.

Differences between normal and demineralized dentine pretreated with silver fluoride and potassium iodide after an in vitro challenge by Streptococcus mutans.

BACKGROUND: The application of diamine silver fluoride (Ag(NH3)2F) and potassium iodide (KI) to demineralized dentine has been shown to inhibit the growth of Streptococcus mutans. The purpose of this study was to observe the differences between demineralized and non-demineralized dentine treated with AgF/KI. METHODS: Thirty-five dentine discs were bonded to the bases of 5 mL polycarbonate screw top vials which were filled with nutrient medium, sterilized and placed into the overflow from a continuous culture of S. mutans. Samples were divided as follows: 10 samples of demineralized dentine; 10 samples of demineralized dentine treated with AgF/KI; 5 samples of non-demineralized dentine; and 10 samples of non-demineralized dentine treated with AgF/KI. Following two weeks connected to the Chemostat, an electron probe microanalysis (EPMA) of percentage weights and penetration depths of calcium, phosphorous silver and fluoride was conducted. Bacterial growth was monitored by taking optical density readings of the growth medium in each vial and outer surfaces of the specimens were examined by scanning electron microscopy (SEM). RESULTS: AgF/KI treatment of demineralized and non-demineralized dentine prevented biofilm formation and reduced further demineralization by S. mutans. AgF/KI treatment of demineralized dentine was more effective in reducing dentine breakdown and the growth of S. mutans. Significantly higher levels of silver and fluoride were deposited within demineralized dentine. CONCLUSIONS: A topical treatment with AgF/KI on dentine reduced in vitro caries development and inhibited surface biofilm formation. Reduction of in vitro caries development and viability of S. mutans was more pronounced on the dentine samples that had been demineralized prior to the application of

Ion uptake into demineralized dentine from glass ionomer cement following pretreatment with silver fluoride and potassium iodide.

BACKGROUND: Diamine silver fluoride (Ag(NH3)2F), referred to as AgF, has been shown to provide a pronounced antimicrobial action against caries. The clinical application of this material has been limited by the staining associated with both teeth and tooth coloured restorative materials. The application of potassium iodide (KI) after AgF eliminates stain formation. The purpose of this study was to determine if a prior application of silver fluoride and potassium iodine to demineralized dentine affected the uptake of strontium and fluoride from a glass ionomer cement restoration. METHOD: Three cavities were prepared in each of five recently extracted human third molars. The cavities were demineralized and treated as follows. In each tooth, one cavity was left as a control, one cavity was restored with glass ionomer cement and one cavity was treated with 1.8M AgF and a saturated KI solution and then restored with glass ionomer cement. The penetration of the various elements into demineralized dentine was measured by their relative percentage weights using electron probe microanalysis (EPMA). RESULTS: Fluoride uptake was significantly higher in the AgF and KI treated samples compared to the other two samples and significantly higher in the glass ionomer restored sample compared to the control. The application of AgF and KI did not significantly interfere with the transfer of strontium from glass ionomer cement into dentine. Silver and iodine deposits were present in the demineralized dentine treated with AgF and KI. CONCLUSIONS: The application of AgF and KI onto dentine prior to the placement of glass ionomer cement did not significantly affect the strontium uptake into the subjacent demineralized dentine and the fluoride levels in this zone were significantly increased.

An in vitro model to measure the effect of a silver fluoride and potassium iodide treatment on the permeability of demineralized dentine to Streptococcus mutans.

BACKGROUND: Diamine silver fluoride (Ag(NH3)2F), referred to as AgF, has been used to reduce the incidence of caries in primary dentitions but has been limited by the associated staining of both teeth and restorative materials. The application of potassium iodide (KI), following AgF prevents staining but its effects on the ability of AgF to reduce caries are not known. The aim of this study was to develop an in vitro model that would provide an indication of the permeability of demineralized dentine to Streptococcus mutans after treatment of the dentine with AgF followed by KI. METHODS: Forty dentine discs were bonded to the base of forty 5mL polycarbonate screw top vials (that had had their bases removed), filled with nutrient medium, sterilized and placed into a continuous culture of S. mutans. Samples were divided into four groups as follows: 10 samples of demineralized dentine as a control, 10 samples of demineralized dentine treated with AgF/KI, 10 samples of demineralized dentine treated with KI and 10 samples of demineralized dentine treated with AgF. After two weeks the optical density of the growth medium chambers was measured to determine bacterial penetration and growth. Cultures were plated out to determine migration through the discs by S. mutans. RESULTS: S. mutans migrated through all dentine discs. However, the samples treated with AgF and AgF/KI had significantly lower optical densities than the corresponding controls. The range of optical densities was least amongst demineralized samples treated with AgF/KI. CONCLUSIONS: Under the conditions of this study, treatment of demineralized dentine discs with AgF followed by KI allowed the penetration of S. mutans. Based on optical density measurements, the treatment resulted in significantly fewer microorganisms being present subjacent to the discs treated with AgF and KI than the control discs at the end of the experimental period.

Clinical appearance of permanent successors after nonextraction treatment of grossly carious primary molars in highly anxious children.

After taking into account the local constraints, a treatment plan was devised to introduce children to dental procedures in gradual stages. An alternative nonextraction approach was adopted. Children between the ages of five and ten years were chosen for the acclimatization program; and 65 percent of their permanent successors to treated primary molars showed no defects.

Changes in the caries experience of 12-year-old Sydney schoolchildren between 1963 and 1982.

A study of the caries experience of 12-year-old children attending public high schools in the northern suburbs of Sydney was undertaken in 1982. The data obtained were compared with those from a similar study conducted in the same area in 1963. In the period between the two examinations, Sydney's water supply was fluoridated and fluoride toothpastes became widely available. There was a major improvement in dental health in the 19-year interval between the surveys. The mean number of decayed, missing, and filled teeth (DMFT) per child declined from 8.49 in 1963 to 1.37 in 1982, a reduction of 84%. An analysis of the DMFT index showed that the greatest reductions occurred in the decayed tooth (DT), and missing tooth (MT) components (95% and 94%, respectively). In 1982, in contrast to the situation in 1963, the backlog of unmet restorative dentistry needs was low.

Economic aspects of the prolonged fluoride application method.

Cost-benefit and cost-effectiveness analyses were carried out to obtain an indication of the economic viability of the prolonged fluoride application (PFA) method. Using three year results from a clinical trial of the technique, the cost-benefit ratio has calculated as 1:2.1 and the cost-effectiveness as $3.49 per surface saved in three years. For purpose of general comparison the same analyses were made for an alternative measure, the placement of pit and fissure sealants. Using data from a two-year sealant trial, the cost-benefit ratio was found to be 1:0.77 and the cost-effectiveness $18.49 per surface saved in two years. The findings indicated that the PFA method can be regarded as an economically viable procedure.

Caries progression in primary molars: 24-month results from a minimal treatment programme.

A 2-stage topical treatment regimen (AgF followed by SnF2) was used in an attempt to limit caries progression in the primary molars of children participating in a minimal treatment programme. The children lived in an isolated community in western New South Wales (fluoride in water less than 0.2 parts/10(6)) and were from a low socioeconomic background. The progression, over a 24-month period, of 281 established lesions in the approximal and occlusal surfaces of primary molars in 54 subjects (mean age 7.0 years) was determined from bitewing radiographs. Of the lesions studied, the majority (69%) were in dentine at baseline. At 24 months, 74% of the approximal surface lesions and 90% of the occlusal surface lesions that were in enamel at baseline remained unchanged. The greatest change occurred in the approximal surface lesions that were within 1 mm of the pulp at baseline. Only 35% of the lesions required any treatment other than topical metal fluoride therapy during the 24-month period.

Effect of stannous fluoride treatments on the progression of initial lesions in approximal surfaces of permanent posterior teeth.

Bite-wing radiographs were used to determine the effect of three forms of topical SnF2 therapy on the progression of initial lesions in the approximal surfaces of permanent posterior teeth. Radiographs were taken annually over a four-year period. The subjects were schoolchildren, aged 12-14 yr, living in a low fluoride area. The professional application of a 10% SnF2 solution for 30 s, semi-annually for two yr, had no discernible effect on the development of the initial lesions. However, the home use of a SnF2 dentifrice did inhibit caries progression appreciably at all but one of the four time intervals in the study. The professional application of a 10% SnF2 solution for 30 s, semi-annually for two yr, combined with the home use of a SnF2 dentifrice, was the most effective treatment in retarding lesion development. Even without topical fluoride therapy, the rate of progression of initial approximal lesions was generally quite slow. In view of these findings, it would seem sound clinical practice to treat all initial lesions in approximal surfaces with topical fluoride therapy and delay placement of restorations until there is radiographic evidence of lesions reaching dentin.

Towards a rational approach to topical fluoride therapy at the mixed dentition stage.

Suggestions are given as to the means whereby the professional application of topical fluoride solutions at the mixed dentition stage can be rationalized. One requirement is that the objective of such therapy be clearly understood. Whilst the prevention of new caries lesions is an obvious aim, the importance of slowing or arresting existing early lesions should be appreciated. Data from clinical studies indicate that topical treatments should be directed at newly erupted teeth concentrating on sites with the highest caries susceptibility. At the mixed dentition stage much of the preventive effort must of necessity be directed at pits and fissures in permanent first molar teeth. A prolonged fluoride application (PFA) method provides one means of treating these sites in partially or fully erupted teeth.