Effects of an acidic calcium phosphate solution and the intraoral fluoride-releasing device on dental caries and fluoride uptake in rats

This investigation comprised two studies evaluating the effects of an acidic calcium phosphate solution (CPS) on fluoride uptake in the enamel, glycolysis of dental plaque, the incidence of dental caries and urinary fluoride concentrations of rats wearing an intraoral fluoride-releasing device (IFRD). In the first study, CPS-fluoride treatment preceded the cariogenic challenge. In the second study, the cariogenic challenge preceded the treatments. In the first study, CPS treatments increased the ability of enamel to bind fluoride. However, the enamel-bound fluoride exerted a negligible effect on plaque glycolysis as measured by the pH decrease after sucrose challenge. In the second study CPS augmented the caries inhibition for both the sulcal-morsal and buccal-lingual surfaces. In both studies the IFRD significantly restricted the development of carious enamel on the sulcal-morsal surfaces and caused elevated concentrations of fluoride in the urine independent of CPS treatments.     

An intraoral study of caries induced on enamel in contact with fluoride-releasing restorative materials

The aim was to study the effect of three fluoride-releasing restorative materials on sound enamel of approximal teeth under cariogenic conditions intraorally. Bovine enamel slabs were paired with four hemispherical samples from each of three test materials (Ketac Molar, ESPE; Vitremer, F-2000, both from 3M) and one control material (Pertac II, ESPE). Their curved surface touched enamel at a contact point allowing space for plaque accumulation. Pairs were inserted in the buccal flanges of 2 lower dentures for 70 days. Initially and upon dismantling, enamel surface microhardness was measured and the increase in length of indentation in micrometers was recorded at a distance of 0, 0.4, 0.8 and 1.2 mm from the contact point. Respective values were: Pertac II: 16.0+/-7.5, 27.6+/-15.4, 38.6+/-23.3, 47.8+/-25.2; F-2000: 11.89+/-9.6, 15.8+/-14.2, 21.0+/-15.0, 25.1+/-15.2; Ketac Molar: 6.6+/-6.8, 9.4+/-7.0, 9.5+/-8.0), 13.4+/-9.4; Vitremer: 2.7+/-4.1, 3.5+/-3.5, 3.6+/-4.5), 7.4+/-5.2. Caries protection was Vitremer 82% > Ketac Molar 69% >F-2000 42% in relation to Pertac II (p<0.001). Sections of the slabs examined with polarized light showed typical subsurface lesions only in the Pertac II group, areas of pseudoisotropy in the F-2000 and Ketac Molar groups and no signs of lesion in the Vitremer group.     

Inhibition of artificial secondary caries by fluoride-releasing adhesives on root dentin

Fluoride-releasing materials can be expected to inhibit the secondary caries. The aim;of this study was to evaluate the effect of fluoride-releasing adhesives on inhibition of secondary caries in outer and wall lesions. Two commercial fluoride-releasing adhesives, Reactmer bond (RB) and One-up bond F (OB), and a commercial adhesive without fluoride release, Mac-bond II (MB), were used prior to placement of restorative materials without fluoride release, Lite-fil II A (LF) and Estelite (EL), and a fluoride-releasing restorative material, Reactmer paste (RP). Class V cavities prepared on extracted human premolars were restored with various combinations of the materials: MB/EL, OB/EL, RB/LF and RB/RP. The restored teeth were incubated in bacterial medium containing sucrose with Streptoccus mutans for 14 days. Microradiographs of specimens showed no wall lesions in all groups and an acid-resistant layer adjacent to the restoration in the caries-like lesion. OB/EL, RB/LF and RB/RP groups showed thicker layers than the MB/EL group. The RB/RP group formed the shallowest outer lesion among all groups. These results indicate that fluoride-releasing adhesives are effective in the prevention of wall lesions but exhibit little outer lesion inhibition. Therefore, combined restoration using a fluoride-releasing adhesive and fluoride-releasing restorative material should be selected to inhibit secondary caries.     

Inhibition of artificial secondary caries in root by fluoride-releasing restorative materials

This investigation evaluated the fluoride-releasing properties of various fluoride-releasing restorative materials, including resin-modified glass-ionomer cements (Fuji ionomer TypeII LC, Photac-Fil Aplicap, Vitremer), compomers (Ionosit FIL, Compoglass, Dyract) and fluoride-releasing resin composites (Heliomolar radiopaque, Degufill mineral). The study also estimated the effects of those materials on the inhibition of artificial secondary caries around restorations using a bacterial caries-inducing system. The amount of fluoride released from the materials in deionized water was measured every one week for 10 weeks. Class V cavities with the gingival margin located in the root were prepared in extracted human premolars and restored with each of the materials. The restored teeth were incubated in the bacterial artificial caries chamber, and the artificial lesion created around the restoration was observed microradiographically. The resin-modified glass-ionomer cements released the largest amount of fluoride and created a thick radio-opaque zone in the artificial lesion along the restoration-dentin interface. These results indicated that the fluoride-releasing restorative materials have the potential to inhibit secondary caries formation around restorations. Resin-modified glass-ionomer cements presented a particularly strong effect, compared with compomers and fluoride-releasing resin composites.     

Evaluating the effects of fluoride-releasing dental materials on adjacent interproximal caries.

BACKGROUND: The authors examined several restorative materials to evaluate their ability to inhibit demineralization and enhance remineralization of incipient carious lesions on the interproximal enamel of teeth adjacent to those restored with the materials. METHODS: Twenty-one subjects in need of a crown on a mandibular molar and a Class II inlay on an adjacent tooth took part in this six-phase study. Artificial enamel lesions were created and positioned within the interproximal portion of a crown. Lesions were photographed with polarized light microscopy and characterized before and after 30-day intraoral exposures. Each phase included the placement of a new section in the crown model and a new Class II inlay restorative material in the adjacent tooth. RESULTS: Results demonstrated that nonfluoridated resin composite, fluoridated resin composite and resin-modified glass ionomer restorative materials, when placed in subjects who brushed with a fluoridated dentifrice, demonstrated significantly (P < .05) less enamel demineralization than the nonfluoridated resin composite control placed in subjects who brushed with a nonfluoridated dentifrice. The resin-modified glass ionomer cement, however, even when brushed with a nonfluoridated dentifrice, exhibited significantly (P < .05) less demineralization than the nonfluoridated resin composite control brushed with a nonfluoridated dentifrice. CONCLUSIONS: Resin-modified glass ionomer cement appears to significantly inhibit demineralization of interproximal enamel of teeth adjacent to those restored with the material. CLINICAL IMPLICATIONS: Resin-modified glass ionomer cement restorations can enhance prevention of enamel demineralization on adjacent teeth.     

Fully digital fabrication of an occlusal device using an intraoral scanner and 3D printing: A dental technique

This dental technique describes a fully digital method for fabricating occlusal devices using a complete-arch intraoral scan and 3D printing. The maxillary and mandibular arches of a healthy, fully dentate volunteer were digitized using an intraoral scanner. A second scan and modified recording of the centric relation enabled a virtual arrangement of the maxillary and mandibular arches, both in centric relation and in the desired vertical dimension of occlusion. An occlusal device was subsequently designed virtually and fabricated from a light-polymerizing acrylic resin using a 3D printer. The occlusal device was tested for fit, occlusion, and patient-friendly handling. As only minor occlusal corrections were required, the fully digital procedure described is suitable for the fabrication of occlusal devices.     

电脑比色仪比色结果的可重复性研究

目的研究Shade Eye NCC电脑比色仪比色结果的可重复性以及与目测比色结果的差异性。方法10名自愿者参加试验,由两名测试者使用Shade Eye NCC电脑比色仪对测试对象的右上颌中切牙进行测试．记录比色仪推荐的Vita比色板色号。3周后进行重复测量并记录结果。另外两名测试者对相同测试对象进行目测比色。计算电脑比色法同一测试者前后两次比色和不同测试者之间比色结果的一致性,以及目测比色法不同测试者比色结果的一致性。结果电脑比色法两位测试者前后两次比色结果的一致性分别为90％和80％．两位测试者之间比色结果的一致性为80％。目测比色法两位测试者D、E之间比色结果的一致性为80％。结论使用Shade Eye NCC电脑比色仪进行比色,其结果具有很高的可重复性。可将其用于辅助临床比乜．以及牙齿漂白过程中的疗效判定。     

Pharmacological evaluation of an intra-oral fluoride-releasing device in adolescents

The purpose of this study was to quantify fluoride (F) concentrations in body fluids of adolescents wearing two intra-oral fluoride-releasing devices (IFRDs) designed to release 0.10 mg F/day. Fluoride concentrations were determined potentiometrically. No significant increases occurred in urine or serum F concentrations during the 26-week device phase. Elevated salivary F concentrations were maintained throughout the device phase when broken or depleted IFRDs were replaced. However, salivary F concentrations returned to pre-device phase values by 26 weeks when the original IFRDs were maintained. These findings suggest that IFRDs can significantly elevate salivary F concentrations of adolescents without significant elevations in systemic F concentrations.     

The repeatability of an intraoral dental colorimeter

STATEMENT OF PROBLEM: Characterizing and reproducing color remain one of the most challenging aspects of dentistry. A relatively new intraoral colorimeter measures the color of natural teeth and metal-ceramic restorations and prints out a color recipe for the Vintage Halo Porcelain System. The reliability of the colorimeter is unknown. PURPOSE: The purpose of this study was to evaluate the reliability of a contact dental colorimeter and to correlate the shade registered by the colorimeter with the shade selected by experienced clinicians. MATERIALS AND METHODS: In part I of the study, 2 examiners (A and B) took 2 colorimeter measurements from the maxillary right central incisors of 11 subjects. The examiners were blinded to their own data and those of other investigators. The readings were repeated 3 weeks later with the same protocol. The Cronbach alpha reliability coefficient was used to analyze the collected data. In part II of the study, 2 experienced clinicians (examiners D and E) selected a shade from the classic Vita Lumin Vacuum shade guide for the maxillary right central incisors of the same 11 subjects. The clinicians were blinded to each other's selections and the colorimeter readings. It should be noted that the manufacturer of the colorimeter uses the terms shade, value, and hue to represent chroma, value, and hue, respectively, as defined in the Glossary of Prosthodontic Terms (J Prosthet Dent 1999;81:39-110). RESULTS: The reliability analysis results for each of the combined trials for shade, value, and hue were all >.94. The interexaminer reliability alpha values were >.9 for shade and value and.64 to.74 for hue. The interexaminer alpha represented the value range of each of 4 measurements. The intraexaminer reliability alpha values for shade, value, and hue were.99,.95, and.96 for examiner A and.99,.93, and.97 for examiner B, respectively. In part II of the study, the colorimeter agreed with itself 82% of the time, whereas clinicians agreed with each other on the selected shade 73% of the time. Selections made by the colorimeter and the clinicians matched 55% to 64% of the time. CONCLUSIONS: Within the limitations of this study, the colorimeter reliably measured the color of natural teeth.     

Inhibition of experimental caries by plaque prevention

abstract – The purpose of this study was to test the hypothesis that a frequent intake of sucrose does not produce caries if the teeth are regularly treated with an antibacterial agent. Twenty-four students with clean teeth and normal gingivae were assigned to one of the following three groups: (1) eight individuals ceased all active oral hygiene measures and rinsed 9 times daily with 50% sucrose, (2) eight students refrained from all active oral hygiene procedures, rinsed 9 times daily with sucrose and twice daily with 10 ml 0.2% chlorhexidine gluconate, (3) the third group consisted of two subgroups each comprising 4 students. One subgroup ceased all oral hygiene procedures and rinsed twice daily with 0.2% chlorhexidine gluconate. The other was instructed to practice meticulous tooth brushing twice daily. The experiment lasted for 22 days. The group who rinsed with sucrose showed heavy plaque accumulation, those who rinsed with sucrose + chlorhexidine showed a drastic reduction in the formation of plaque. In the subgroup rinsing with chlorhexidine only and in that performing good oral hygiene, plaque was non-existent. The gingival state essentially paralleled the plaque formation. The sucrose group showed a definite increase in Caries Index. No significant changes occurred in the group rinsing with sucrose + chlorhexidine, with chlorhexidine only, or in the group performing good oral hygiene. It is concluded that prevention of plaque formation inhibits the development of gingivitis and dental caries, even with frequent rinses of sucrose.     

Changes of bacterial flora on inbred mouse strains using experimental dental caries model

In the experimental dental caries model using inbred mouse strains, the bacterial flora of lower molars were investigated during the process of caries induction to examine the differences of bacterial flora between the caries susceptive mouse strains (BALB/cA, C57BL/6N) and the caries resistant mouse strain (C3H/HeN), as well as the relation between the bacterial flora and Streptococcus faecalis that seemed to be the pathogen of caries on this caries model. The total cultivable bacterial number immediately after weaning (3 weeks old) was larger in the caries susceptive strains than in the caries resistant strain. The composition of Gram(+) cocci, Gram(+)rods and Gram(-)rods varied in each strain and Gram(-)cocci were not isolated from any of the strains. The proportion of Gram(+)cocci to the total cultivable bacterial number was larger in the caries susceptive strains than in the caries resistant strain, while S. faecalis was the most predominant species in Gram(+)cocci in all strains. It suggests that S. faecalis existed indigenously on the lower molars of mice at the time of weaning (3 weeks old). The total cultivable bacterial number increased in all strains as feeding with Diet-2000 which contains 30% sucrose started. The number reached its peak on the fifth week, and it either remained the same or slightly declined after that. The number of S. faecalis also reached the peak between third and fifth week. The order of 10(5) - to 10(6) S. faecalis was isolated from the caries susceptive strains, and the order of 10(4) from the caries resistant strain throughout the experimental period. It suggests that C3H/HeN (the caries resistant strain) mice have certain caries resistant factors in the genetic background. Toward the end of the experimental period, S. acidominimus in the caries susceptive mice and Staphylococcus sciuri in the caries resistant mice increased and replaced S. faecalis. Gram(+)rods also increased in the caries susceptive strains. It seems that Gram(+)rods have some relation with the progress of advanced dental caries.     

Maxillary advancement using distraction osteogenesis with intraoral device

This article describes the surgical orthodontic treatment of maxillary hypoplasia in a patient with cleft lip and palate using maxillary distraction osteogenesis with internal maxillary distractors. Maxillary advancement was performed to correct the retrusive maxillary facial profile and Class III malocclusion. Rotational movement of the distraction segment was made to correct the upper dental midline. Although maxillary advancement was insufficient because of unexpected breakage of the intraoral distractor after completion of the distraction, skeletal traction with a face mask compensated for the shortage. Successful esthetic improvement and posttreatment occlusal stability were achieved with no discernible relapse after 2 years of retention.     

Enamel fluoride uptake from an experimental fluoride-releasing orthodontic adhesive.

The purpose of this study was to evaluate quantitatively the fluoride uptake by enamel from an experimental visible light-cured orthodontic adhesive (VP-862) based on YbF3 filler. Sixteen contralateral premolars were extracted from 10 orthodontic patients and were classified in four groups (A, B, C, D) of four buccal surfaces each. Standardized enamel areas located on these surfaces were acid etched and were subjected to the following adhesive treatments: (A) VP-862; (B) Heliosit Orthodontic; (C) Heliobond + VP 862; and (D) Heliobond + Heliosit Orthodontic. Groups B and D were used as a reference. After 9 months in vivo, the teeth were extracted and cross-sectioned, and the enamel-adhesive interfaces were studied by combined wavelength-energy dispersive electron probe microanalysis. According to the results, the cumulative fluoride uptake by enamel from the experimental adhesive was not statistically different from the fluoride detected in the reference groups. No effect of the liquid resin, Heliobond, on the fluoride uptake gradients of enamel could be differentiated.     

Light intensity evaluation of laser-induced fluorescence after caries removal using an experimental caries staining agent

OBJECTIVE: The purpose of this study was to evaluate the intensity of fluorescent light reflected from cavity wall dentin, after dentin stained by an experimental caries detecting liquid was removed. BACKGROUND DATA: The conventional caries detecting liquid tends to penetrate dentin too deeply. On the other hand, DIAGNOdent has gradually gained recognition and established itself as a caries detection device using a laser beam. METHOD: An experimental caries staining liquid or the conventional caries staining liquid was applied in the same cavity to observe for differences in dye penetration. Intensity of fluorescence reflected from treated dentin was measured by DIAGNOdent. RESULTS: The mean DIAGNOdent value after removing the tooth substance stained by the experimental liquid was 17.9+/-4.1, compared with 7.7+/-2.7 by conventional one. CONCLUSION: Light intensity evaluation of laser-induced fluorescence suggested that the experimental caries detecting liquid did not penetrate the dentin which should be preserved, hence avoiding overtreatment.     

Effects of a fluoride-releasing fissure sealant on artificial enamel caries

This study examined the effect of a fluoride-releasing fissure sealant upon enamel demineralization in an artificial-caries system. Twenty extracted human molars were randomly assigned to two treatment groups consisting of (1) conventional fissure sealant and (2) fluoride-releasing sealant. Specimens were acid-etched, rinsed, dried, sealant applied, and photocured for 20 seconds. Teeth were thermocycled 500x between 5 degrees C and 55 degrees C using 1 minute dwell times. Acid-resistant varnish was placed on the specimens to within 1 mm of the sealant and the teeth were subjected to an artificial-caries challenge at pH 4.2 for 62 hours. Teeth were then sectioned and the thin-sections photographed using a polarizing-light microscope. Areas of the artificial-caries lesions and their depths were measured using a sonic-digitizing pad. Mean lesion depths (in arbitrary units from the digitizing pads) were 4.17 +/- 0.95 for Group 1 and 1.22 +/- 0.61 for Group 2. Mean areas were 17.26 +/- 7.32 for Group 1 and 3.12 +/- 2.59 for Group 2. Students' t-tests indicated statistically significant differences (P less than 0.001) between groups for both measures. This artificial-caries study indicates that a fluoride-releasing fissure sealant substantially reduces the amount of enamel demineralization adjacent to the material.     

美蓝预防龋病的实验研究

目的：研究美蓝对变形链球菌生长、产酸代谢的作用和对体外菌斑糖酵解模型产酸代谢的作用，以及动物实验研究美蓝预防龋病的效果，为美蓝预防龋病的临床应用提供实验依据。方法：采用比浊法测定不同培养条件下变形链球菌培养液的吸光度A值；采用气相色谱法检测不同培养条件下变形链球菌培养液中有机酸的种类和数量；测定不同处理条件下体外菌斑糖酵解模型产酸液的pH值；采用Keyes龋病评分法观察美蓝对Sprague-Dawley（SD）大鼠磨牙龋的预防效果。结果：①美蓝组细菌A值低于生理盐水组，二者之间的差异具有统计学意义。②不同血清型变形链球菌的3个处理组中均可检测到有机酸的产生，葡萄糖组有机酸的总量最多，美蓝组有机酸的总量最少。③美蓝组产酸液的pH值与阴性对照组之间的差异有统计学意义，与阳性对照组之间的差异无统计学意义。④在E级和Ds级两级龋损中，美蓝组与蒸馏水组相差非常显著（P〈0.01），与氟化钠组相差不显著（P〉0、05）；Dm级龋损仅见于蒸馏水组，美蓝组或氟化钠组均未发生；Dx级龋损在3组中均未出现。结论：美蓝可以抑制变形链球菌的生长、产酸代谢和菌斑的产酸代谢，能够减少SD大鼠磨牙龋的发生。     

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.