使用不同氟制剂后菌斑氟浓度的动态变化

目的 通过测定志愿者使用不同氟制剂后菌斑氟浓度，观察Fluor Protector，Bilfluoride，0．2％NaF漱口水，1．23％APF泡沫四种氟制剂使用后，氟在口腔菌斑中的动态变化，了解不同剂型的氟制剂在口腔中的释放情况，为临床选择有效的氟制剂提供实验依据。方法 选择56名志愿者，用离子选择性氟电极测定使用四种氟制剂后1、3、7天菌斑氟浓度，并与基线水平相比较。结果 无论是使用哪种类型的氟制剂，菌斑氟浓度都显著提高，0．2％NaF漱口水，1．23％APF泡沫只在第一天时高于基线，Fluor Protector和Bilfluoride在第一天、第三天都高于基线，Bilfluoride在第七天时仍然高于基线。结论 作为缓释制剂的双氟漆和氟保护漆延长了氟在菌斑中的停留时间，使氟的清除速度降低，这有利于防龋作用的发挥。     

四种方式局部用氟对牙菌斑产酸力的影响

目的探讨氟化物对含漱糖溶液后菌斑产酸力的影响，以期为合理、正确使用氟制剂防治龋齿提供实验依据。方法采用4种局部用氟方式，分别为含氟牙膏刷牙，含氟牙膏刷牙加每天1次0.05％氟化钠漱口液含漱，含氟牙膏刷牙加每周1次0．2％氟化钠漱口液含漱，含氟牙膏刷牙加试验时即刻使用0．2％氟化钠漱口液含漱。采用微型pH电极接触法检测使用氟化物后菌斑pH在含漱蔗糖溶液后1h内的变化；同时用分光光度计法检测菌斑内变形链球菌的含量。结果只有当含漱蔗糖的同时给予氟化物才能有效抑制菌斑pH下降，在含漱后各时间点菌斑pH均未发生明显变化，维持在6，0以上；而其他方式用氟后菌斑pH仍可下降至临界值5.5以下；4种用氟方式对菌斑内变形链球菌的含量无明显影响。结论氟化物可抑制菌斑内的产酸代谢活动，但这种抑制作用受菌斑内氟离子浓度的影响；在含漱糖溶液的同时给予氟可有效地抑制菌斑内酸的形成，降低菌斑的产酸力。     

咀嚼麦芽糖醇口香糖对牙菌斑原位pH值的影响

目的探讨咀嚼麦芽糖醇口香糖后牙菌斑原位pH值的变化趋势。方法将30名13～15岁龋易感儿童随机分为3组，即麦芽糖醇口香糖组（A组）、木糖醇口香糖组（B组）、胶母口香糖组（C组）。通过微电极原位接触法对牙菌斑pH值进行检测，观察咀嚼口香糖4W前后菌斑pH值的变化趋势。结果三组受试者分别在咀嚼口香糖后，菌斑pH值于各个时间点均呈上升趋势，约20min达到最高值，随后仍保持高于基线值水平。咀嚼口香糖4周后，三组各时间点牙菌斑pH值均上升，与咀嚼前比较具有显著性差异（P〈0．05）；三组间在各个时间点pH值上升幅度（△pH）比较具有显著性差异（P〈0．05）。结论麦芽糖醇口香糖对牙菌斑pH值的作用同木糖醇口香糖一样较为明显。     

用于牙菌斑pH测定的复合型微pH电极的研制

目的　研制可用于测定菌斑pH值的微pH电极。方法　用循环伏安法聚苯胺修饰钨丝电极作为pH指示电极 ,用Ag AgCl丝作为参比电极 ,二者复合于塑料套管内构成复合型pH微电极 ,试用于菌斑pH的测定。结果　在pH3～ 12范围内 ,该电极呈现Nernst响应 ,响应时间 <2min。将该电极试用于菌斑pH测定 ,获得蔗糖含漱后菌斑pH变动曲线。结论　该电极可用于菌斑内pH测定 ,且有望用于体内其它微小环境pH测定。     

Fluoride concentration in plaque in adolescents after topical application of different fluoride varnishes

The aim of the study was to measure the fluoride (F) concentration in plaque after a single topical application of different fluoride varnishes with contrasting levels of F. Thirty adolescents (12–17 years) with fixed orthodontic appliances were randomly assigned to one of three groups: Bifluoride (6% F), Duraphat (2.23% F) and Fluor Protector (0.1% F). The varnishes were applied after professional cleaning in one upper quadrant, leaving the opposite quadrant untreated according to the split-mouth technique. Pooled plaque samples from each quadrant were collected at baseline and 3 days, 7 days and 30 days after the varnish treatment, and fluoride was analysed by microdiffusion. All fluoride varnishes increased the fluoride concentration in plaque compared with baseline, and the mean values varied between 23 and 138 ng F/mg after 3 days, depending on varnish F concentration. Compared with the control quadrant, statistically significant elevations were recorded for Bifluoride after 3 days and 7 days and Duraphat after 3 days, while no significant differences were revealed in the Fluor Protector group. The fluoride concentration in plaque was back to baseline levels for all participants in the Duraphat group after 7 days, while some individuals in the Bifluoride and Fluor Protector groups still registered slightly increased levels after 30 days. The results suggest that fluoride varnish treatments resulted in elevated fluoride levels in plaque adjacent to fixed orthodontic appliances for a period of up to 1 week, although different patterns was disclosed for the various brands. Received: 5 October 1999 / Accepted: 18 November 1999     

Buffering effect of a prophylactic gel on dental plaque

The aim of this study was to evaluate the effect of a new prophylactic gel on plaque pH and plaque fluoride concentration. Twelve participants with normal (n=6, ≥0.7 ml/min) and low (n=6, <0.7 ml/min) stimulated whole salivary secretion rate were included. After 3 days of plaque accumulation, at random the participants were (1) treated with Profylin fluoride gel with buffering components (active gel), (2) treated with Profylin fluoride gel without buffering components (placebo gel), (3) asked to rinse with water, and (4) given no treatment. All test series were followed by rinsing with a nutrition solution; after which registration of plaque pH was performed during 60 min. There were two drop outs with low salivary secretion rate in the water session. The overall least pronounced pH fall was found after the use of the prophylactic gel. Significant differences between the prophylactic gel and the placebo gel were found for the participants with normal secretion rate. Fluoride plaque concentrations evaluated in 12 individuals after (1) application of the active gel, (2) rinsing with 0.2% NaF, and (3) rinsing with water showed significantly higher values after rinsing with the NaF solution. It can be concluded that application of the active gel, particularly in subjects with normal salivary secretion rate, in general, buffered plaque pH to higher levels. Factors like concentration of buffering agent and solubility of the gel need to be further evaluated to improve the effect.     

Effect of fluoride sustained slow-releasing device on fluoride, phosphate and calcium levels in plaque biofilms over time measured using ion chromatography

Objectives

To determine whether there are any differences in fluoride (F), calcium (Ca) or phosphate (PO₄) concentrations in natural plaque biofilms between the upper right and left quadrants using a fluoride sustained slow-releasing device (FSSRD) placed in the upper right quadrant after 7 and 21 days. To report and validate a new methodology in measuring very low concentrations of F in dental plaque and saliva using ion chromatography.

Methods

Twenty-one participants were divided into two groups with 11 participants in group one and 10 in group two. Each participant had a FSSRD attached to the upper right second permanent molar and two plaque generating devices (PGDs) attached to the upper right and left first permanent molars. The PGDs were recovered after 7 days in group one and 21 days in group two.

Results

At both 7 and 21 days (right, left), F (1.081 ± 1.517 ppm, 0.736 ± 0.840 ppm) and (0.459 ± 0.888 ppm, 0.203 ± 0.139 ppm), PO₄ (1053 ± 533 ppm, 654 ± 246 ppm) and (865 ± 1099 ppm, 474 ± 304 ppm) and Ca (136 ± 132 ppm, 74 ± 36 ppm) and (130 ± 109 ppm, 77 ± 24 ppm), were higher in the quadrant containing the FSSRD but not significantly so (p > 0.05). Fluoride and PO₄ fell in both quadrants between 7 and 21 days, though not significantly.

Conclusions

Intriguingly while not statistically significant, 21 day plaque contained less fluoride than those investigated after 7 days. While the data was not statistically significant, it seems possible that F, Ca and PO₄ accumulated around the device to a limited extent but were washed away fairly quickly and distributed around the oral cavity.

Clinical importance

The FSSRD was found to reduce dmfs/DMFS by 76% and raise salivary F levels by ∼10 folds. This device is very helpful in reducing dental decay where compliance is impaired such as in patients with special needs. This study further investigates the anti-cariogenic effect of this device.     

菌斑原位pH在判断个体龋易感性中的作用

口内牙齿表面菌斑的原位pH既能反映细菌代谢产酸的能力,也反映局部环境缓冲和转运酸的能力。本研究使用钯-微触电极测量龋活跃者(CA)和无龋者(CF)在用10％蔗糖溶液漱口前后菌斑的原位pH,以评价原位pH测定在判断个体龋易感性中的作用。结果表明,龋活跃组菌斑pH在漱糖前后各时间点均较无龋组低;龋活跃组与无龋组在漱糖后菌斑下降的最低pH相近,但龋活跃组菌斑pH回升速度慢,导致低pH水平持续时间长。上颌牙菌斑pH水平较下颌牙菌斑pH水平低,而左右侧牙菌斑pH水平大致相同,提示唾液在维持菌斑pH水平中的主导作用。     

Influence of pH and oxygen-inhibited layer on fluoride release properties of fluoride sealant

OBJECTIVES: This study tested the hypothesis that the oxygen-inhibited layer on a light-cured methacrylate based resin and the pH of the storage medium would increase significantly the initial fluoride release and long-term release rate from fluoride dental sealant. METHODS: Forty-eight discs (16-mm diameter x 1-mm thick) were made from FluroShield (<5 wt% NaF) and Helioseal F (<30 wt% fluorosilicate glass) sealants. For each sealant, 24 discs were cured through a Mylar strip that covered the surface and the remaining 24 discs were cured in air allowing formation of the oxygen-inhibited surface. Each specimen in the 24-disc groups was stored individually in 25-mL vials, and divided into four six-vial groups to receive 10 mL of pH4-pH7 (designation of pH 4-7) lactate buffer solutions. The buffer solutions were replaced periodically up to 121 days. The cumulative fluoride release over time was used to determine the coefficients for short-term and long-term release. RESULTS: Two-way ANOVA showed that the mean coefficient values for either sealant were significantly influenced by the curing condition (p<0.0001) and pH (p<0.0001), except for short-term release from NaF sealant. The duration of short-term release was much longer for the fluorosilicate glass sealant. CONCLUSIONS: Both pH and the source of fluoride source incorporated in the sealant play significant roles in fluoride release.     

Mass transfer of therapeutics through natural human plaque biofilms: a model for therapeutic delivery to pathological bacterial biofilms

Bacterial biofilms in the mouth are prime mediators of the destruction of the dental and oral tissues. This brief review summarises recent work using a device for generating intact plaque in the mouth on natural enamel surfaces such that quantitative studies of mass transfer through natural plaque biofilms could be carried out in relation to plaque architecture. This data is discussed against the background of existing information. The device revealed complex plaque architecture with high a surface area to mass ratio decreasing from the exterior of the biofilm towards the tissue surface. Fluoride, a potent inhibitor of caries was concentrated in the outer regions of the biofilm. This implies some restriction of diffusion and possibly binding to the high surface area of the outer biofilm. Whilst all components examined conformed to this distribution pattern, some relatively uncharged materials penetrated the bacterial biomass whilst other, more highly charged materials tended to be restricted to the channels or biomass surface. Plaque architecture was robust but could be altered using detergent indicating that biomass architecture and chemistry could be manipulated as a possible means of facilitating mass transport of therapeutics.     

Penetration of fluoride into natural plaque biofilms

Caries occurs at inaccessible stagnation sites where plaque removal is difficult. Here, the penetration through plaque of protective components, such as fluoride, is likely to be crucial in caries inhibition. We hypothesized that topically applied fluoride would readily penetrate such plaque deposits. In this study, plaque biofilms generated in vivo on natural enamel surfaces were exposed to NaF (1000 ppm F-) for 30 or 120 sec (equivalent to toothbrushing) or for 30 min. Biofilms were then sectioned throughout their depth, and the fluoride content of each section was determined with the use of a fluoride electrode. Exposure to NaF for 30 or 120 sec increased plaque fluoride concentrations near the saliva interface, while concentrations near the enamel surface remained low. Fluoride penetration increased with duration of NaF exposure. Removal of exogenous fluoride resulted in fluoride loss and redistribution. Penetration of fluoride into plaque biofilms during brief topical exposure is restricted, which may limit anti-caries efficacy.     

固定矫治器粘结前后牙齿颊面菌斑pH值和变形链球菌附着的改变

目的对固定矫治器粘结前后牙颊面菌斑pH值和变形链球菌附着量、比例进行研究,初步探讨固定矫治中菌斑微生态的变化。方法应用离子选择性微电极测定菌斑提取液的pH值,对变形链球菌和总厌氧菌进行培养,记数。结果固定矫治器粘结后牙面菌斑pH值有极显著的下降(p<0.001),粘结一周后下降了0.5,三周后下降了0.7。菌斑湿重在粘结后三周有显著增多(p<0.05)。变形链球菌附着量、比例有极显著的升高(p<0.001)。粘结后一周,变形链球菌的数目平均上升了8.85×1011CFU/g;粘结后三周,平均上升了4.20×1011CFU/g,比例增加了1.10％。结论固定矫治器粘结后颊面菌斑的致龋性增强,但并未转化为致龋性菌斑。固定正畸与龋易感性的关系有待进一步研究。     

The effect of casein and calcium containing paste on plaque pH following a subsequent carbohydrate challenge

Objectives

Previous research has shown that regular use of CPP–ACP increases calcium and inorganic phosphates in plaque and reduces enamel mineral loss. The aim of this study was to investigate if a CPP–ACP-containing paste would neutralize acidic challenges in dental plaque following sucrose rinse.

Method

Plaque pH was measured on 15 subjects in a cross-over study with and without prior application of the paste and with and without CPP–ACP. On each occasion, subjects rinsed with 10% sucrose and sorbitol solutions for 2 min in randomized order.

Results

The results showed the median lowest pH without paste was 4.8 (IQR: 4.7–5.0) and with mousse 5.6 (IQR: 5.5–5.6 and p < 0.001). The median lowest pH was 5.0 (IQR: 4.9–5.3) without CPP–ACP and with CPP–ACP was 5.8 (5.6–6.1 and p < 0.001). The time that pH remained below 5.7 and the time to return to resting pH showed similar differences in all subjects (p < 0.01).

Conclusion

The results indicate that prior application of a CPP–ACP-containing paste reduced the fall in plaque pH following a sucrose challenge.     

Effect of nonfluoridated milk and fluoridated milk on acidic dental plaque

PurposeRecovering the acidic plaque pH to its resting value as soon as possible after exposure to a sugary beverage might reduce the risk of dental caries. Milk contains nutrients that help to buffer acid. Adding fluoride to milk might enhance this effect. Accordingly, this study investigates the effect of milk and fluoridated milk on acidic dental plaque.MethodsThe study was a randomized crossover design. Ten subjects were asked to rinse for 2 min with the following solutions: (1) water, (2) 10% sucrose, (3) milk, (4) fluoridated milk, (5) 10% sucrose followed by water, (6) 10% sucrose followed by milk, or (7) 10% sucrose followed by fluoridated milk. The supra-gingival plaque was collected before rinsing and every 5 min after rinsing to measure the plaque pH.ResultsThe results showed that rinsing with 10% sucrose caused acidic dental plaque. After rinsing with 10% sucrose followed by milk, fluoridated milk, or water, the maximum plaque pH dropped and the area under the curve was significantly less than that after rinsing with 10% sucrose alone (p = 0.001). The maximum change in the plaque pH and the area under the curve in the group challenged with 10% sucrose followed by fluoridated milk were significantly lower than those in the group followed by nonfluoridated milk (p = 0.04).ConclusionRinsing with milk could raise the acidic plaque pH to the resting value faster than individual's natural capacity to do so. Adding fluoride to milk can enhance this effect.     

应用新一代高通量测序技术探讨含氟涂料对患龋乳前牙菌斑微生物的影响

目的 应用新一代高通量测序技术,了解含氟涂料处理患龋乳前牙前后菌斑微生物的变化。方法 选取20名乳前牙患龋的学龄前儿童,菌斑生物膜样本采自含氟涂料处理前和处理后3天、7天和30天的乳前牙患龋牙面;抽提全基因组DNA后,用16S rRNA基因V4-V5高变区为引物扩增后,运用MiSeq测序平台测序并分析。结果 4个时间点菌斑生物膜微生物多样性Shannon指数的比较表明,涂氟后3天、后7天比涂氟前的Shannon指数更低（P=0.011;P=0.016）,提示菌斑生物膜的微生物多样性降低;涂氟后30天和涂氟前的Shannon指数持平（P>0.05）,提示涂氟后菌斑生物膜的微生物多样性恢复至涂氟前的状态;PCA分析也进一步表明和Shannon指数一致;4个时间点优势菌属的比较表明涂氟后3天、后7天、后30天和涂氟前优势菌属的种类和相对丰度均没有差异,说明含氟涂料对菌斑生物膜的多样性的抑制作用没有特异性。结论 含氟涂料对患龋乳前牙牙面菌斑微生物在一定时间内有明显的抑制作用,抑制作用无特异性,微生物多样性经过一段时间还能恢复至原有状态。     

Fluoride concentration in supragingival dental plaque after a single intake or habitual consumption of fluoridated milk

The aim of this study was to evaluate the fluoride concentration in supragingival dental plaque after single and repeated intakes of fluoridated milk. The study group consisted of 22 schoolchildren, young adults and adults of both sexes, 8-41 years of age. After a 2-week fluoride depletion period and 3 days of plaque accumulation, 200 ml of fluoridated milk (1g F) was ingested along with a standardized lunch meal. Plaque samples were collected immediately before the intake and after 30, 120 and 240 min. From the adult participants (n = 9), additional samples were colleted after 12 and 18 h. After a fluoride-free washout period of at least 2 weeks, the whole experimental procedure was repeated after 4 consecutive daily intakes of fluoridated milk. The fluoride concentration was determined after micro-diffusion with a fluoride selective electrode. The results showed a statistically significant 3-fold increase of the plaque fluoride levels up to 4 h after the intake. At 12 and 18 h after the intake, the recorded levels went gradually back to baseline. There was no significant difference between the fluoride concentrations in the supragingival plaque after the single intake compared with the repeated intakes. In conclusion, the findings support the suggestion that milk is a suitable vehicle for local fluoride administration into the oral cavity, also when consumed together with a meal.     

Plaque biofilms: the effect of chemical environment on natural human plaque biofilm architecture

The architecture of microbial biofilms especially the outer regions have an important influence on the interaction between biofilm and local environment particularly on the flux of materials into and out of biofilm compartments and as a consequence, biofilm metabolic behaviour. In the case of dental plaque biofilms, architecture will determine access of nutrients including acidogenic substrates and therapeutic materials to the microbial biomass and to the underlying tooth surface. Manipulation of this architecture may offer a means of altering mass transfer into the whole biofilm and biomass and raises the possibility of improving access of therapeutics. Plaque biofilms formed in vivo on human enamel were subjected to a number of different chemical conditions while under observation by confocal laser scanning microscopy in reflection mode. In this way the outer 50-100 microm or so of the biofilms was examined. Density and distribution of biomass were recorded as degree of reflectance. The amount and density of biofilm biomass increased from the plaque saliva interface towards the interior. Plaque biofilms were robust and little affected by mechanical manipulation, high ionic strength or low pH (2.5). Detergent (SLS), however, often appeared to either remove biomass and/or dramatically reduce its density.     

咀嚼木糖醇口香糖对牙面菌斑原位pH值的影响

目的通过对牙面菌斑原位pH值的动态检测，观察咀嚼木糖醇口香糖对牙菌斑pH值的影响。方法采用受试者自身对照的试验方法，选择9名健康成人志愿者为受试对象，用pH微电极在口内测定菌斑的原位pH值。在测定受试者牙面48小时成熟菌斑的基线pH值之后用10％的蔗糖溶液漱口，测定漱口后即刻、3、8、13、20、30、40分钟后菌斑的pH值，然后分别咀嚼蔗糖口香糖和木糖醇口香糖，测量相同时间点、相同位点牙菌斑的pH值。结果用10％的蔗糖溶液漱口后牙菌斑pH值迅速下降至5．5以下，咀嚼蔗糖口香糖后牙菌斑pH值也有下降。但下降幅度较小，在即刻、3、8分钟三个时点二者之间有显著性差异（P〈0．05）。咀嚼木糖醇口香糖后牙菌斑的pH值没有下降，在即刻、3、8、13、20分钟五个时点的pH值明显高于咀嚼蔗糖口香糖后的pH值（P〈0．05）。结论咀嚼木糖醇香糖不会导致口腔中牙菌斑pH值的下降，有助于釉质再矿化。