Biomedical subjects

A Gaffar

Publications and source records attributed to A Gaffar.

At least 37 records · Page 2Linked to original sources

PubMed1996

In vitro and in vivo studies on salifluor/PVM/MA copolymer/NaF combination as an antiplaque agent.

Salifluor (5-n-octanoyl-3'-trifluoromethyl-salicylanilide), a broad spectrum antimicrobial agent, was investigated for its ability to inhibit dental plaque formation. A combination of salifluor with PVM/MA copolymer and NaF was optimized for its antiplaque effect in mouthrinse and dentifrice formulations based on a series of both laboratory and clinical studies. It was found that salifluor, a highly hydrophobic compound, could not be adequately solubilized with the conventional amount of sodium lauryl sulfate (SLS), the most commonly used anionic surfactant in oral hygiene products. However, it was possible to prepare stable mouthrinse formulations using a mixed surfactant system containing both anionic and nonionic surfactants. The most suitable mixture was found to be a combination of SLS, Pluronic and Tauranol in a proportion of 1:1:1. This combination provided adequate stability and high antimicrobial activity as determined by in vitro microbiological tests. Addition of a PVM/MA copolymer to the formulation improved the adsorption and retention of salifluor on stimulated tooth surfaces in vitro (saliva coated hydroxyapatite disks) by almost two-fold and also increased the antiplaque efficacy in both laboratory and human clinical studies. It was also found that a non fluoride dentifrice containing a combination of salifluor and PVM/MA copolymer with a dicalcium phosphate dihydrate abrasive, was highly effective in reducing smooth surface and fissure caries in rats. The results of the present studies demonstrated that salifluor is an effective antiplaque agent in mouthrinse and dentifrice when carefully formulated to maximize its delivery and bioavailability on oral surfaces. They also illustrated the difficulties encountered in exploiting the antimicrobial efficacy of highly hydrophobic, nonionic antimicrobial agents such as salifluor in commonly used oral hygiene vehicles.

Adsorption↗

PubMed1995

The effect of triclosan on developing gingivitis.

The aim of the study was to examine whether triclosan has an effect on developing gingival inflammation. 10 volunteers, with clinically healthy gingivae were enrolled. The study was performed as a 2-week, double-blind, cross-over, experimental gingivitis trial. Between each plaque accumulation period, there was a wash-out phase of 4 weeks. A baseline examination was performed which included assessment of plaque and gingivitis. The volunteers were asked to refrain from mechanical oral hygiene measures for 2 weeks. During this period, they rinsed 2x daily with one of the randomly assigned mouthrinse preparations. Solution A (period A): 0.06% triclosan+ 2%tween 80. Solution B (period B): 0.06% triclosan+ 0.25% sodium lauryl sulphate. Re-examinations were performed on days 4, 7, 11 and 14. The mean plaque score increased during period A to 2.2 (day 4), 2.8 (day 7), 3.1 (day 11) and 3.1 (day 14). The corresponding scores for period B were significantly lower; 1.2 (day 4), 1.8 (day 7), 2.0 (day 11) and 2.2 (day 14). The mean gingivitis scores at baseline were 0.17 (periods A and B). The mean gingivitis scores increased to 0.45 (day 4), 0.69 (day 7), 0.83 (day 11) and 0.96 (day 14) when the subjects rinsed with solution A and 0.42 (day 4), 0.64 (day 7), 0.78 (day 11) and 0.92 (day 14) in period B. There were no statistically significant differences between periods A and B with respect to gingivitis. Thus, although significantly more plaque formed during period A than period B, no differences could be found between the gingivitis scores in the 2 periods.

Adult↗

PubMed1995

The effect of triclosan on mediators of gingival inflammation.

Triclosan (2,4,4',-trichloro-2'-hydroxydiphenylether) is a well-known and widely used nonionic antibacterial agent which has recently been introduced in toothpastes and mouthrinses. The efficacy of triclosan-containing toothpaste and mouthrinse to reduce both plaque and gingivitis in long-term clinical trials has been well documented. Until recently, it was generally assumed that triclosan's effect on gingival inflammation was due to its antimicrobial and anti-plaque effect. It has now become apparent that triclosan may have a direct anti-inflammatory effect on the gingival tissues. Several in vitro studies were conducted to evaluate the effect of triclosan on 4 primary enzymes of the pathways of arachidonic acid metabolism, cyclo-oxygenase 1, cyclo-oxygenase 2, 5-lipoxygenase and 15-lipoxygenase. These pathways lead to the production of known mediators of inflammation such as the prostaglandins, leukotrienes and lipoxins. Triclosan inhibited both cyclooxygenase 1 and cyclo-oxygenase 2 with IC-50 values of 43 microM and 227 microM, respectively. Triclosan also inhibited 5-lipoxygenase with an IC-50 of 43 microM. The 15-lipoxygenase was similarly inhibited by triclosan with an IC-50 of 61 microM. Hence, triclosan has the ability to inhibit both the cyclo-oxygenase and lipoxygenase pathways of arachidonic acid metabolism with similar efficacy. In cell culture experiments, it was found that triclosan inhibited IL-1 beta induced prostaglandin E2 production by human gingival fibroblasts in a concentration dependent manner, and at relatively low concentrations. These data, taken together, indicate that triclosan can inhibit formation of several important mediators of gingival inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Infective Agents, Local↗

PubMed1995

Intra-oral remineralization of enamel with a MFP/DCPD and MFP/silica dentifrice using surface microhardness.

The present study was undertaken to ascertain the effect of dicalcium phosphate dihydrate (DCPD) abrasive in a dentifrice on the remineralizaton of enamel using a surface microhardness technique. The method of assessing enamel remineralization via surface microhardness (SMH) was validated in a randomized, crossover, double-blind, intra-oral remineralization study conducted with 12 healthy adults. Enamel demineralization was achieved in vitro by covering bovine enamel blocks with exogenous oral bacteria, S. Mutans 1600 Ingbritt, containing glucan which was then exposed to sucrose. In the intra-oral treatment phase, subjects were fitted with oral maxillary palatal retainers, each holding four demineralized enamel blocks. Subjects brushed their teeth for 30 seconds with a test dentifrice, swished for an additional 60 seconds, rinsed with water and then retained the blocks intra-orally for 4 hours. Percent mineral recovery for each enamel block was calculated as the ratio of the changes in enamel microhardness due to treatment (remin) and sucrose challenge (demin). Treatments included DCPD-based dentifrices containing 0, 250 and 1000 ppm fluoride (F) from sodium monofluorophosphate (MFP). Using SMH, respective mean percent mineral recoveries of 5.7, 18.7 and 41.4% were obtained. All ADA criteria for model validation were fulfilled. This same model was then used to compare the remineralization effects of a silica placebo, DCPD placebo, 1000 ppm F MFP/silica and 1000 ppm F MFP/DCPD dentifrice. Mean percent mineral recoveries of -0.9, 24.1, 30.2 and 55.7% were obtained, respectively. The MFP/DCPD dentifrice was superior to MFP/silica (<0.01) with use of the MFP/DCPD dentifrice when compared to MFP/silica or the silica placebo. These results indicate that more active calcium and a higher degree of saturation (DS(EN)) with respect to enamel exists for an extended period of time after use of a MFP/DCPD dentifrice. Since an elevation in DS(EN) is considered a major parameter controlling the extent of enamel remineralization, this finding may partly explain the superior remineralization of enamel observed with the MFP/DCPD dentifrice. The significant increases in calcium activity and intra-oral enamel remineralization by the DCPD-based dentifrice are consistent with earlier findings that a DCPD abrasive provides added benefit for enamel remineralization.

Adolescent↗

PubMed1994

Plaque and gingivitis in the deciduous and permanent dentition.

The aim of the present investigation was to monitor de novo plaque formation and associated alterations of the gingival conditions in the deciduous, mixed and permanent dentition in man. 31 volunteers, divided into 3 study groups participated in the trial. Group 1 was made up of 11 subjects, 4-6 years of age (deciduous dentition), group 2 comprised of 10 subjects, 8-9 years of age (mixed dentition) and group 3 included 10 subjects, 14-16 years of age (permanent dentition). After a screening examination, each participant received detailed instruction in a proper oral hygiene technique and was subjected to professional tooth cleaning. The professional debridement and the oral hygiene instruction were repeated after 1 week. After another week, a given day was termed Day 0 and a baseline examination was performed. This examination included assessments of plaque and gingivitis. Each subject received an additional, comprehensive professional tooth cleaning and was asked to abstain from all mechanical oral hygiene measures. Re-examinations were performed after 3 and 7 days. The findings demonstrated that: (i) during a 7-day period of no active oral hygiene, subjects with a mixed or a permanent dentition formed visible amounts of plaque and developed modest signs of gingivitis; (ii) during the 7 days of the trial, young subjects with a fully erupted deciduous dentition formed less plaque than the older subjects, and failed to respond to de novo plaque formation with enhanced signs of gingivitis; (iii) in subjects with a mixed dentition, the amount of plaque formed during the 7 days of experiment and the matching gingivitis development were similar in the deciduous and permanent tooth segments of the dentition.

Adolescent↗

PubMed1994

Chemostat flow cell system: an in vitro model for the evaluation of antiplaque agents.

We developed an experimental in vitro model of dental plaque to assess the potential efficacy of antiplaque agents. The model used a chemostat, which provided a continuous source of 5 species of oral bacteria grown in an artificial "saliva-like" medium. This mixture was pumped through six flow cells, each containing two types of surfaces on which plaque formed and was subsequently measured. Formation of bacterial plaque on hydroxyapatite surfaces was assessed by measurement of the DNA and protein content of the plaque film. The amount of bacterial plaque formed on germanium surfaces was measured by attenuated total reflectance (ATR/FT-IR) spectroscopy. Plaque viability was also assessed by a fluorescent staining technique. The quantity of plaque formed on both types of surfaces gradually increased with the duration of flow (from 24 to 72 h) through the cells during a 72-hour experimental period. The flow cells were then pulsed with experimental treatment solutions for 30 s, twice daily. Parallel to results of human clinical studies, the model was capable of discriminating among water, a placebo mouthrinse, and an active antimicrobial mouthrinse formulation containing 0.03% triclosan. It therefore offers a valuable alternative to animal model testing and allows for more rapid evaluations under well-controlled experimental conditions.

Actinomyces viscosus↗

PubMed1994

Recent advances in plaque, gingivitis, tartar and caries prevention technology.

A dentifrice containing triclosan/PVM/MA, copolymer/NaF (Total) combination was compared with dentifrices containing triclosan without the copolymer system. A variety of laboratory, animal and human studies indicated that Total provided higher uptake and retention of triclosan on teeth, and was more effective in reducing plaque in chemostat and flow cell models. The retention of triclosan in dental plaque was significantly higher with Total as compared with other dentifrices 2 hours post brushing. The triclosan retained in the plaque after using Total was effective against plaque bacteria for up to 12 hours. Other dentifrices did not provide a sustained antibacterial effect against plaque. The results indicated that the delivery system with the copolymer significantly enhanced the efficacy of triclosan against plaque, gingivitis and plaque related diseases in vivo.

Adsorption↗

PubMed1994

Recent advances in stannous fluoride technology: antibacterial efficacy and mechanism of action towards hypersensitivity.

Stannous fluoride (SnF2) is highly susceptible to oxidation and hydrolysis but both anhydrous and aqueous preparations can be well established by proper formulation. When stability in aqueous preparations is achieved by the use of certain strong complexing agents, reduced antibacterial activity is observed which may be attributed to reduced bioavailability of the stannous ion. In contrast, an anhydrous SnF2 preparation maintains stannous ion in a stable but, uncomplexed form. This preparation displays antibacterial activity in saliva and delivers stannous ion which is absorbed onto surfaces making them less susceptible to plaque formation for an extended period of time (hours). When this anhydrous preparation is brushed onto dentine in vitro or in situ, one observes a nearly complete coverage of the dentine surface and occlusion of tubules by a tin-rich surface deposit. This finding indicates that the observed clinical efficacy of this preparation at relieving hypersensitivity is due to occlusion of tubules by a mixture of low solubility complexes of tin. A water-based SnF2 preparation containing strongly complexed stannous ions does not form a surface coating on dentine in vitro suggesting that this preparation may not be optimal for treating hypersensitivity. Overall, the findings indicate that the stannous ions in a SnF2 preparation must be maintained in a stable, bioavailable form for optimal efficacy against plaque and hypersensitivity to be obtained. The results suggest that these properties are provided by stable anhydrous preparations but are difficult to achieve simultaneously in aqueous preparations. When properly formulated, stannous fluoride preparations can provide multiple oral therapeutic benefits.

Bacteria↗

PubMed1994

Evaluation of a new dentifrice for the treatment of sensitive teeth.

A dentifrice containing 5% potassium nitrate, 1.3% soluble pyrophosphate, 1.5% polyvinylmethyl ether and maleic acid (PVM/MA) copolymer and 0.243% sodium fluoride in a silica base (Sensitive/Tartar Control) has been developed to concomitantly control tartar, caries and dentinal hypersensitivity. In vitro and animal studies show that the fluoride in this product effectively inhibits formation of enamel and dentine caries. In vitro studies also demonstrate that this dentifrice effectively reduces hydraulic conductance by occluding dentine tubules with a mixed surface deposit of copolymer and silica. Using an in vitro model that simulates in vivo conditions, this dentifrice also allows a rapid penetration of potassium nitrate through the dentine matrix. These findings demonstrate a correlation under in vivo conditions between the occlusion of dentine and the ability to deliver topically applied agents to target sites within or below dentine. The results indicate that this new dentifrice should provide multiple clinical therapeutic benefits including controlling tooth decay and tartar formation, and reducing and preventing dentinal hypersensitivity.

Animals↗

PubMed1993

In vivo studies with a dicalcium phosphate dihydrate/MFP system for caries prevention.

Recent basic studies have shown that increasing supersaturation with respect to dicalcium phosphate dihydrate (DCPD), above and beyond the amount present in saliva, enhanced the efficacy of fluoride in vitro. Since the combination of monofluorophosphate (MFP) with DCPD abrasive is unique for fluoride stability, dentifrices containing the combination were evaluated in a variety of in vivo tests. MFP with silicon dioxide (silica) abrasive at an equivalent fluoride concentration was used for comparison. The influence of slurries of DCPD or silicon dioxide on the intraoral plaque pH was measured following sucrose challenge in humans. The data indicated that DCPD slurries were more effective than silica in preventing plaque pH drop when compared to silica. A toothpaste containing MFP and DCPD was significantly more effective than an MFP/silica toothpaste. A toothpaste containing radiolabeled DCPD was applied topically in rats' teeth during a cariogenic challenge. The results showed that calcium45 was incorporated into the enamel with a concomitant reduction in enamel solubility. In a rat caries study using MFP/DCPD, matching placebo and MFP/silica, MFP/DCPD dentifrice showed a significantly greater reduction in smooth surface caries. Two dentifrices were also tested in an in situ human model for fluoride uptake in artificial root caries lesions where MFP/DCPD provided a significantly higher fluoride uptake than MFP/silica. A second in situ study in humans evaluated the same dentifrices. MFP/DCPD increased salivary plaque calcium and fluoride. These results of laboratory, animal and in situ studies taken together indicate that the MFP/DCPD combination is unique in providing extra supersaturation in saliva and plaque with concomitant enhanced anticaries efficacy.

Animals↗

PubMed1992

A model for studying the effects of mouthrinses on de novo plaque formation.

The aim of the present study was to describe a 4-day no oral hygiene model to assess the pattern of de novo plaque formation and to use this model to appraise the potential of some mouthwash preparations to retard or inhibit plaque formation in the human dentition. 10 subjects were recruited for the trial. During a preparatory period, the participants were exposed to repeated professional plaque control and given oral hygiene instruction to eliminate signs of gingivitis. At the end of the preparatory period, each participant received a final professional tooth cleaning and was subsequently told to abstain from mechanical plaque control efforts for the next 4 days. They were asked to rinse twice daily for 60 s with 10 ml varying test solutions. On Day 4, the volunteers were exposed to a new clinical examination and the presence and amount of plaque were examined by the use of the plaque index system (P1I). The participants were subsequently given a professional tooth cleaning and asked to exercise proper self performed plaque control during the next 10 days. A new test period was then initiated. 6 different mouthwash preparations were tested in each subject namely, (1) placebo (a negative control rinse), (2) Veadent mouthrinse, (3) Listerine mouthrinse, (4) 0.06% triclosan + polyvinyl phosphonic acid (PVPA), (5) 0.06% triclosan + phenolic flavor and (6) 0.12% chlorhexidine digluconate (a positive control rinse). The results from the study revealed that the mean P1I values for individuals, groups of teeth and tooth surfaces provide an adequate but gross overall estimation of the potential of a given mouthrinse to retard/inhibit plaque build up. More detailed information on the effects of the test rinses could be obtained by data describing the % distribution of different P1I score categories; a high frequency of score 0 describes the potential of a mouthrinse to maintain tooth surfaces free from plaque while a low frequency of score 2/3 describes the ability of a treatment to retard/prevent gross plaque formation. The plaque pattern displays finally allowed assessment of the magnitude of plaque prevention, in comparison to the positive and negative controls, that could be achieved by a given compound in various parts and surfaces of the dentition. In this model, all test rinses (i) were significantly more effective than the placebo rinse in retarding de novo plaque build up and (ii) had a minor effects on plaque build up in the maxillary molars and at the approximal surfaces.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1992

Fluoride availability in human saliva after dentifrice use: correlation with anticaries effects in rats.

Studies were conducted to determine fluoride availability in saliva after dentifrice use and to relate this parameter to cariostatic efficacy in rat caries experiments. Three dentifrices--two commercial formulations (Colgate Winterfresh Gel and Crest Dentifrice with Na-Sr-polyacrylate) and an Experimental dentifrice--were compared with respect to salivary fluoride availability. All of the dentifrices tested contained 1100 ppm F as sodium fluoride. It was observed that the Experimental dentifrice and Crest dentifrice with Sr-polyacrylate exhibited low salivary fluoride availability relative to the Colgate Winterfresh Gel. Salivary fluoride availability was assessed by means of two parameters: (a) the fluoride concentration in the dentifrice saliva slurry expectorated after brushing, and (b) the area under the curve of salivary F concentration vs. time for up to two hours after dentifrice use. In two rat caries experiments, it was observed that both the Experimental dentifrice and the Sr-polyacrylate dentifrice provided less cariostatic efficacy than the clinically validated Positive Control (Colgate Winterfesh Gel). Analysis of these data provides further evidence in support of the concept that fluoride availability in saliva following dentifrice use is an important parameter related to anticaries efficacy.

Acrylic Resins↗

PubMed1992

General principles for the delivery of active agents from mouthrinses.

Mouthrinses are a convenient and accepted method of delivering oral therapeutic agents. Efficacy, however, depends on several factors including the type of drug used and its properties, use of an optimal delivery vehicle, patient compliance or usage practices and the therapeutic indication for which they are used. Three classes of therapeutic agents currently used in mouthrinses are reviewed, including fluorides, tartar control agents and antimicrobial compounds. The specific agents in these categories, some of which are currently used in mouthrinses, span a broad range of chemical and pharmacological properties. A basic understanding of these properties allows for a rational use of these agents in therapeutically optimised formulations.

Anti-Infective Agents↗

PubMed1991

Effects of potassium peroxydiphosphate on bone resorption.

Potassium peroxydiphosphate (KPDP) is a slowly hydrolyzed pyrophosphate analog that can release hydrogen peroxide during hydrolysis. We tested its effects on the resorption of cultured fetal rat long bones as measured by the release of previously incorporated 45Ca, both by direct addition of KPDP to the medium and after preincubation of KPDP with large-molecular-weight resorbing factors followed by dialysis to reduce the KPDP concentration. With direct addition, KPDP at a concentration of 1 mM could inhibit the resortive response to bacterial lipopolysaccharide (LPS), parathyroid hormone (PTH), prostaglandin E2 (PGE2), and mouse recombinant interleukin-1 (mrIL-1). The response to LPS was partially inhibited at 0.3 mM KPDP. Control resorption in the absence of stimulators was also inhibited. Potassium pyrophosphate at 1 mM was less effective as an inhibitor of bone resorption. The inhibitory effects of KPDP did not appear to be due entirely to nonspecific toxicity since partial recovery occurred after it was removed. There was no significant decrease in [3H]thymidine or [3H]proline incorporation into bones incubated with KPDP at 1 mM for 5 days, but [3H]proline incorporation was decreased at 24 h, suggesting that KPDP may have a general inhibitory effect on bone cells. When media with and without stimulators of resorption were incubated overnight at 4 degrees C with KPDP at 5.8 mM and then dialyzed to bring the concentration to below 0.3 mM, the bone-resorbing activity of PTH, LPS, and mrIL-1 was completely lost. This may have been due to the slow release of hydrogen peroxide; however, preincubation with equimolar concentrations of H2O3 caused only partial inactivation of PTH and LPS. LPS.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

113Cd nuclear magnetic resonance (NMR) study of the inhibitory effect of methylvinylether/maleic acid (PVM/MA) copolymer on the alkaline phosphatase of Escherichia coli.

The inhibitory effect of PVM/MA copolymer on the alkaline phosphatase (AP) of E. coli was investigated. Kinetic studies indicated that enzyme inhibition was characterized by a reduction in both the Vmax and the Km. Addition of 1 mM zinc or magnesium ions to the reaction prevented inhibition of the enzyme by the copolymer. The inhibitory effect of the copolymer on alkaline phosphatase was also investigated using 113Cd NMR after exchange of the active center metal ions with 113Cd. The resulting Cd(II)6AP exhibited characteristic 113Cd resonances reflecting the environment of the A, B, and C metal binding sites of the enzyme's active center. Addition of copolymer resulted in a 113Cd NMR spectrum which indicated removal of 113Cd from the C site and formation of two distinct forms of the enzyme. Possible explanations for the 113Cd NMR results are discussed.

Alkaline Phosphatase↗

PubMed1991

Evaluation of tartar control dentifrices in in vitro models of dentin sensitivity.

The effects of anticalculus dentifrices were compared with other commercially available dentifrices in in vitro models of dentin sensitivity. Changes in the hydraulic conductance of dentin discs were measured with and without a smear layer before and after treatment and also after a post-treatment acid etch. The capacity of dentifrices to occlude open dentinal tubules in vitro was also assessed by scanning electron microscopy (SEM). There was good correlation (R = 0.98) between our test and values reported in the literature. Tartar control dentifrices gave reductions in fluid flow rates through the dentin discs comparable to those obtained with Promise, Sensodyne, Thermodent and Denquel. Additionally, tartar control dentifrices did not remove microcrystalline debris (smear layers) from the surfaces of dentin in vitro. These results were confirmed by SEM. Thus, according to the hydrodynamic theory of dentin sensitivity, these in vitro results suggest that pyrophosphate-containing dentifrices should reduce dentinal sensitivity.

Dental Calculus↗

PubMed1991

Influence of an anticalculus mouthrinse treatment on the dentition and periodontium in beagle dogs.

This research evaluated the effect of an anticalculus mouthrinse, containing 3.3% pyrophosphate anion and 1.0% of a copolymer of vinylmethyl ether and maleic acid (Gantrez), on calculus formation, gingivitis, gingival recession, and epithelial attachment in beagle dogs over a one-year period of time, compared to a distilled water rinse. Each was applied twice a day for the one-year period. Compared to the control, the anticalculus mouthrinse resulted in significant reductions in the formation of calculus and gingivitis, as well as a prevention of loss of epithelial attachment in the beagle dogs. The results from this investigation suggest that it is possible to mitigate both probing epithelial attachment loss and increases in probing pocket depth at the calculus prone sites through the use of an anticalculus mouthrinse.

Analysis of Variance↗

PubMed1990

In vitro and in vivo anticalculus effects of a triclosan/copolymer system.

The effect of PVM/MA copolymer on hydroxyapatite crystal growth in vitro at 37 degrees C was evaluated. The copolymer provided a 50% inhibition of the growth rate at 35 ppm for 220 minutes. The polymer adsorbed to saliva-coated hydroxyapatite disks and the adsorption was time and concentration dependent. Under exaggerated in vitro conditions, the copolymer did not etch or damage enamel surfaces at pH 5.5 and 7.5. It was highly effective against calculus formation in rats when applied topically yielding a 54% reduction (P less than or equal to 0.01). In beagle dogs, it reduced calculus formation significantly (P = 0.06) over a period of 24 to 28 weeks when applied topically either as a rinse or toothpaste. Collectively, the data indicated that the copolymer was an effective anticalculus agent when applied topically, in the presence of triclosan.

Adsorption↗