Caries inhibiting effect of ammonium fluoride varnish in vitro

The reaction of incorporation of fluoride into tooth enamel from NH4F varnish, and Duaphat were measured using SEMq2 in vitro. Level of enamel uptake of fluoride was highest in teeth treated with NH4F varnish. Average depth of fluoride penetrated into enamel was more than 80 microns from the two varnishes. Prolonged coating duration from 24 hours to 1 week did not increase uptake and penetration of fluoride from both varnishes. The NH4F varnish was found to be superior to Duraphat in terms of inhibiting artificial caries lesion formation (P less than 0.001).     

Role of remineralizing fluid in in vitro enamel caries formation and progression.

OBJECTIVE: To evaluate a remineralizing fluid for its influence on in vitro caries formation and progression. METHOD AND MATERIALS: Caries-free teeth (n = 12) were sectioned into 3 segments. Each segment was assigned to a treatment group: (1) remineralizing fluid for 2 minutes; (2) 1.23% acidulated phosphate fluoride (APF) gel for 1 minute; (3) no-treatment control. Following treatment, the tooth segments were rinsed in distilled/deionized water and exposed to synthetic saliva for 24 hours. In vitro caries were formed and longitudinal sections obtained. The tooth segments were treated again and rinsed as above, before undergoing in vitro caries progression. Longitudinal sections were evaluated for lesion depth (ANOVA, Duncan multiple range analysis). RESULTS: Following lesion formation, mean lesion depths were 173 +/- 19 microm for no-treatment control; 97 +/- 11 microm for APF gel; and 52 +/- 12 microm for remineralizing fluid. After lesion progression, mean lesion depths were 236 +/- 23 microm for no-treatment control; 184 +/- 26 microm for APF gel; and 112 +/- 17 microm for remineralizing fluid. Mean lesion depths for the remineralizing fluid and APF gel groups for the lesion formation and progression periods were significantly less than those for the control group (P < .05). After lesion formation and progression, the APF group had significantly greater mean lesion depths than did the remineralizing fluid group (P < .05). CONCLUSIONS: A remineralizing fluid containing calcium, phosphate, and fluoride in a carbopol base enhanced resistance against in vitro caries formation and progression when compared with APF treatment.     

In vitro cytotoxicity of a remineralizing resin-based calcium phosphate cement.

Recently, a resin-based calcium phosphate cement (RCPC) has been reported as a remineralizing pulp-capping or lining cement. RCPC consists mainly of tetracalcium and dicalcium phosphates, ethoxylated bisphenol A dimethacrylate and pyromellitic glycerol dimethacrylate monomers and photo- and chemical initiators. OBJECTIVES: Here, the cytotoxic effects of RCPC were evaluated. The hypothesis was that RCPC induced only minor cytotoxic response in immortalized murine odontoblast and pulp cells, comparable to that produced by similar dimethacrylates due to unpolymerized dimethacrylate monomer present after curing. METHODS: Cytotoxicity was determined following the changes in cell succinate dehydrogenase activity after 24 h exposure to the cement components and after a 24 h recovery period. A fourfold range of concentrations was tested of the monomers, the eluate of cured RCPC leached in Dulbecco's modified Eagle's medium, and crushed cured cement in dimethyl sulfoxide. RESULTS: The monomers themselves had cytotoxicities similar to those reported for other dimethacrylates, although they are significantly less toxic than Bis-GMA. Differential cell sensitivity was demonstrated, with the pulp cells having greater sensitivity to the unpolymerized monomer than the odontoblast-like cells. The leached components have cytotoxicity similar to that of the free monomers. The crushed material demonstrated no apparent cytotoxicity at the dilutions tested. SIGNIFICANCE: These data demonstrate that RCPC has an in vitro cytotoxicity that is comparable to other materials containing dimethacrylate monomers and suggest that the material may be suitable for use in dental restorations. The data also indicate that the pulp cells appear more sensitive to dimethacrylates than the odontoblasts.     

The effect of xylitol and fluoride on remineralization for primary tooth enamel caries in vitro

The effect of fluoride and xylitol on remineralization at the early stage of the enamel caries in primary tooth was studied. The samples were divided into four groups (control, 10% xylitol, 950 ppm NaF and 10% xylitol+950 ppm NaF) and analyzed by the using single thin section method and pHcycling model in vitro. The remineralizing ratio were control –8.9%, xylitol –0.4%, NaF 8.3% and xylitol + NaF 32.4%, respectively. Xylitol+NaF group particularly showed significantly smaller ΔZ value compared with 0 days (P<0.05). Therefore we assume that the effect of xylitol and fluoride are additive. We concluded that xylitol and fluoride treatment to the tooth enamel may be an effective caries-preventive measure in both primary and permanent tooth enamel.     

Caries-preventive and remineralizing effect of fluoride gel in orthodontic patients after 2 years

Patients with orthodontic appliances exhibit a higher caries risk, but they are often excluded from preventive studies. Thus, the aim of this observational study was to assess the caries-preventive and remineralizing effect of a high-fluoride gel in orthodontic patients. Two hundred twenty-one orthodontic patients (age, 6-19?years; mean, 13.1?±?2.3; n?=?104 with use of a 1.25% fluoride gel weekly at home, 117 participants without) were recruited and followed for 2?years, recording caries (decayed/missing/filled teeth (DMFT)/decayed/missing/filled surface (DMFS), active/inactive lesions), orthodontic treatment, use of fluorides, plaque and gingivitis. Baseline values regarding demographic and clinical parameters were equivalent for the 75 participants using fluoride gel and the 77 individuals of the control group who completed the study. The initial plaque and gingivitis values (approximal plaque index (API), 37%?±?34 and 42%?±?39, resp.; papillary bleeding index (PBI), 19%?±?28 and 22%?±?27, resp.) deteriorated slightly during the 2-year study (API, 54%/56%; PBI, 25%/28%). The increase in carious defects or fillings was minimal in both groups (fluoride, 0.75 DMFT?±?1.2, 1.27 DMFS?±?1.9; control, 0.99?±?1.3 and 1.62?±?2.6, resp.) without reaching statistical significance (p?=?0.12 for DMFT, 0.44 for DMFS). The main statistically significant effect of the fluoride use was the reversal of active initial lesions diagnosed (fluoride group, -0.96?±?1.82; control, -0.19?±?2.0, p?=?0.004), while the number of inactive initial lesions increased (2.3?±?2.1 and 1.7?±?2.1, resp.; p?=?0.02). In conclusion, the weekly application of a fluoride gel in orthodontic patients can reduce their caries activity. Initial caries lesions in orthodontic patients can be inactivated by weekly fluoride gel use at home.     

Effect of xylitol and fluoride on enamel erosion in vitro

This study aimed to determine the anti-erosive effects of xylitol, fluoride and a xylitol/fluoride combination used as an additive in an acidic drink or as mouthrinse after enamel was exposed to an acidic drink, in vitro. Human third molars were divided into 7 groups (A-G). Samples from groups A to D were immersed for 5 min in orange juice only (A), orange juice plus either 25% xylitol (B), F(-) 1 ppm (C) or a 25% xylitol/F(-) 1 ppm combination (D), respectively. Samples from groups E to G were immersed in orange juice for 5 min and then in either 40% xylitol (E), F(-) 227 ppm (F) or a 40% xylitol/F(-) 227 ppm combination (G), for 1 min respectively. This process was performed four times daily for 14 days. Mineral loss was determined from the lesion depth and surface hardness. Erosion depth progressively increased in all groups, except E, where erosion depth was significantly lower than group A. Surface microhardness progressively decreased in all groups, except E, where hardness was significantly higher than group A. This study demonstrated that addition of xylitol, fluoride or a xylitol/fluoride combination to an acidic drink or post-treatment with fluoride or a xylitol/fluoride combination could reduce, but not prevent, enamel erosion.     

The remineralizing effect of an essential oil fluoride mouthrinse in an intraoral caries test

BACKGROUND: The authors conducted a two-week clinical study to determine the remineralizing effect of an experimental mouthrinse containing both fluoride and essential oils in an intraoral caries test model. METHODS: The study used an observer-blinded, randomized, controlled, 3 x 3 crossover design. The authors enrolled in the study 153 subjects, each of whom had a mandibular removable partial denture. Two partially demineralized human enamel specimens were mounted on each subject's removable partial denture. Subjects used either a fluoride mouthrinse with essential oils (the test mouthrinse), a fluoride nonessential oils mouthrinse (the positive control) or an essential oil nonfluoride mouthrinse (the negative control) twice daily for 14 days. The researchers assessed specimens for mineral content change and fluoride uptake using surface microhardness, or SMH, testing and enamel fluoride analysis, respectively. RESULTS: Of the 153 subjects enrolled in the study, 125 subjects were evaluable at the study endpoint. The results after two weeks showed that percentage of SMH recovery was 42 percent in the test group, 36 percent in the positive control group and 16 percent in the negative control group. The fluoride uptake was 19 micrograms per square centimeter, 16 microg/cm2 and 3 microg/cm2 for the test mouthrinse, positive control and negative control groups, respectively. In terms of both percentage of SMH and fluoride uptake, the test mouthrinse and positive control mouthrinse were statistically higher than the negative control mouthrinse, and the test mouthrinse was "at least as good as" the positive control mouthrinse. CONCLUSIONS: This study provides evidence that an essential oil mouthrinse with 100 parts per million fluoride is effective in promoting enamel remineralization and fluoride uptake. CLINICAL IMPLICATIONS: The combination of fluoride and essential oils in a mouthrinse may provide anticaries efficacy, in addition to essential oils' previously established antigingivitis efficacy.     

Effect of a bonding agent on in vitro biochemical activities of remineralizing resin-based calcium phosphate cements

OBJECTIVES: To test whether fluoride in a resin-based Ca-PO4 ion releasing cement or coating with an acidic bonding agent for improved adhesion compromised the cement remineralization potential. METHODS: Cements were formulated without fluoride (Cement A) or with fluoride (Cement B). The treatment groups were A=Cement A; A2=Cement A+bonding agent; B=Cement B; B2=Cement B+bonding agent. The calcium, phosphate, and fluoride ion release in saliva-like solution (SLS) was determined from hardened cement disks without or with a coating of bonding agent. For the remineralization, two cavities were prepared in dentin of extracted human molars and demineralized. One cavity received composite resin (control); the other received treatment A, A2, B or B2. After 6 week incubation in SLS, 180 microm cross-sections were cut. The percentage remineralization was determined by transverse microradiography comparing the dentin mineral density under the cement to that under the control. RESULTS: The percentage of remineralization (mean+/-S.D.) was A (39+/-14)=B (37+/-18), A2 (23+/-13), B2 (14+/-7). Two-way analysis of variance (ANOVA) and Holm-Sidak test showed a significant effect from the presence of bonding agent (p<0.05), but not from fluoride (p>0.05). The ion solution concentrations of all groups showed undersaturation with respect to dicalcium phosphate dihydrate and calcium fluoride and supersaturation for fluorapatite and hydroxyapatite suggesting a positive remineralization potential. SIGNIFICANCE: Compared to the control all treatments resulted in mineral increase. The remineralization was negatively affected by the presence of the bonding agent.     

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目的探讨体外酪蛋白磷酸肽(CPPs)抑制人牙釉质脱矿的作用。方法选择2006年6—8月在山西医科大学口腔医院因正畸治疗拔除的健康前磨牙30颗,制作30粒圆形平面开窗区釉质块(直径4mm),其余部分由抗酸指甲油涂抹封闭。根据开窗区釉质的显微硬度(HK0.02),将30粒釉质块完全随机分为5组,每组6粒,分别进行5种不同处理(A组:去离子水和去离子水;B组:CPPs和去离子水;C组:去离子水和乳酸;D组:CPPs和乳酸;E组:氟保护剂和乳酸),使用原子吸收光谱分析法检测釉质表面溶出钙量,比较各组溶出钙量的差别。结果A组、B组和E组间钙溶出量差异无统计学意义(P>0.05),C组和D组间钙溶出量差异无统计学意义(P>0.05),但A组、B组和E组均比C组和D组溶出钙量少,差异有统计学意义(P<0.05)。结论CPPs没有直接阻止脱矿的作用,但也不会使釉质表面发生脱矿;氟保护剂形成的漆膜能够有效抵抗酸的腐蚀作用。     

The effect of xylitol on plaque metabolism

Evidence is presented which shows that Strep. mitior and Strep. mutans (which are unable to metabolize xylitol) take yp xylitol and transfer it to xylitol phosphate. Dental plaque also takes up xylitol. In this case a xylitol/protein complex is formed in addition to xylitol phosphate and also some labelled components yet to be identified. It is suggested that accumulation of xylitol phosphate inside the cells may "poison" the bacteria and possibly explain the caries therapeutic effect of xylitol observed in some laboratories.     

酪蛋白磷酸肽钙磷复合体治疗正畸后釉质脱矿的临床研究

目的研究酪蛋白磷酸肽钙磷复合体(CPP-ACP)对正畸后釉质脱矿的治疗作用。方法选择63例正畸治疗结束后,上牙(14~24,或15~25)唇面釉质存在轻度到中度脱矿的患者,随机分为2组:试验组31例,对照组32例。两组均给予含0.14%氟牙膏刷牙,每天晚上刷牙结束后试验组在脱矿牙牙面应用含有CPP-ACP的GC护牙素,对照组应用除不含CPP-ACP成分外,其他成分相同的安慰剂糊剂。临床检测指标为牙釉质脱矿指数(EDI)。观察时间为正畸结束当天,治疗1、3个月后,采用STATA12.0软件包对数据进行单因素方差分析。结果 58例完成试验(试验组28例,对照组30例),两组EDI总和均较治疗前降低。治疗前,治疗1个月后3个月后试验组的EDI分别为(0.5903±0.2585),(0.4514±0.2077),(0.2396±0.1499);对照组为(0.5291±0.2494),(0.4397±0.2068),(0.3287±0.1757)。治疗前和治疗1个月后两组EDI的差异无统计学意义,治疗3个月后试验组EDI少于对照组,差异有统计学意义。结论可以通过使用含CPP-ACP的GC护牙素来治疗正畸后釉质脱矿。     

The effect of xylitol and chlorhexidine acetate/xylitol chewing gums on plaque accumulation and gingival inflammation

Chewing gums may be suitable vehicles for the delivery of xylitol (X) and chlorhexidine acetate (CHX), both of which can aid oral health. The aim of this study was to determine the clinical effectiveness of chewing gums containing X or a combination of X and CHX in a double-blind, randomised, cross over, 5-day clinical trial, with a 9-day washout period in a group of participants over 40 years old. After professional tooth cleaning, 8 subjects (mean age 51.3+/-10.4 years) used in a random order 2 pieces of ACHX (a liquorice flavoured CHX/X) gum, 2 pieces of BCHX (a chocolate mint flavoured CHX/X), 2 pieces of X (a liquorice flavoured X gum) and 1 piece of ACHX. Gums were chewed 2x daily for 15 min and volunteers refrained from all other oral hygiene procedures. Data were analysed using Friedman nonparametric analysis of variance. Plaque indices for chewing 2 pieces of ACHX gum (0.78+/-0.15) and BCHX gum (0.52+/-0.15) were significantly lower (p<0.0006) than for X gum (1.57+/-0.08). The gingival index was significantly greater (p<0.05) for X containing gum than for the other chewing regimes. The subjects' attitudes to the gums were also assessed by structured questionnaires which showed that all gums were easy to chew, did not adhere to dentures, teeth or restorations and that the subjects preferred to chew 2 pellets rather than 1.