Low Fluoride Concentrations Research Articles

Electric properties of oxyfluorides Ba2In2O5−0.5x F x with brownmillerite structure

Synthesis of fluoro-substituted substances based on brownmillerite Ba2In2O5 is carried out. The width of the homogeneity region of the Ba2In2O5−0.5x F x (0 < x ≤ 0.25) solid solution was established using X-ray analysis. Measurement of temperature dependences of conductivity in atmospheres with different partial pressure of water vapor (pH2O = 3.3 and 2 × 103 Pa) showed an increase in conductivity at T ≤ 550°C in a humid atmosphere, which is due to appearance of proton transport. The dependence of conductivity on partial oxygen pressure (pO2 = 0.21 × 105 to 10−15 Pa) is studied in the temperature range of 500–1000°C; ion transport numbers are calculated. The method of polarization measurements was used to determine transport numbers of fluoride. Total conductivity is divided into ion (proton, oxygen, and fluoride ion) and electron components. Analysis of concentration dependences of conductivities showed that low concentrations of fluoride allow increasing both the total and partial conductivities (oxygen-ion and proton) and, besides, allow shifting the “order-disorder” phase transition by 100°C to the low temperature range.

Drinking water fluoride concentration and its relationship with decayed, missing, and filled teeth index in Mianeh, Iran

Aims: The aim of this study was to determine fluoride levels in drinking water of Mianeh city and to evaluate decayed, missing, and filled teeth (DMFT) index in children between 6 and 9 years old. Materials and Methods: This cross-sectional research was carried out on all sources of drinking water including 14 groundwater sources in Mianeh city. A total of 56 samples were taken from all wells during four seasons of 2009 and analyzed with colorimeter SPADNS method with DR 2500 spectrophotometer set17. Results: The results show that the means of source fluoride concentration in spring, summer, autumn, and winter seasons were 0.295 ΁ 0.039 mg/l, 0.47 ΁ 0.17 mg/l, 0.48 ΁ 0.18 mg/l, and 0.4 ΁ 0.06 mg/l, respectively. This means that the concentration of fluoride in all sources was below national standards, but they were in permissible range proposed by WHO. In addition, the DMFT index of the children between 6 and 9 years old in Mianeh city was higher than national mean. Conclusions: Considering the low fluoride concentration in water sources of Mianeh, it was proposed that a chemical compound such as sodium fluoride be added to provide fluoride ion. It seems that the low fluoride levels in supplied water have a significant effect on higher DMFT index in children of the subjected community.

Migration of fluoride ions from the permanent teeth into saliva in children with glass ionomer cement restorations: An in vitro study

Glass ionomer cements (GIC) belong to the group of polycarboxyl cements, and one of the principal characteristics of these materials is their anticariogenic potential of fluorine release into saliva and enamel-dentin substance. The aim of this study was to examine the content of released fluorine from GIC restorations (Fuji IX, GC, Japan) of young permanent teeth in the medium of artificial saliva and similar releases in the same medium by the restorations of these teeth treated with a low concentration fluoride solution. We examined 12 premolars extracted from orthodontic reasons. The GIC restored teeth were divided into the group treated daily with low concentration fluoride solution (334 ppm) and the control, not treated group. The samples of artificial saliva were analyzed for fluorine ion content using an ion selective electrode. Our comparative analysis of the mean values using the Student's t-test demonstrated a statistically significant difference in fluorine ion concentration in artificial saliva of fluoridated and non-fluoridated teeth with GIC fillings after 14 and 21 days (p < 0.05), while the difference detected after 7 days was with no statistical significance. The results of this in vitro study indicated that low-concentration fluoride solutions could serve to refluoridate GIC fillings and contribute to an increased fluorine content in saliva. The process of refluoridation of GIC fillings should be advised 2-3 weeks after the restoration, since the release of fluorine from GIC fillings diminishes in time.

Sorption of fluoride on partially calcined dolomite

Natural dolomite was calcined at different temperatures in the range 873–1373K and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption/desorption isotherm. The calcination temperature had considerable effect on the surface chemical composition, crystallinity, and basicity of CO2 gas sorption of each component in the calcined products. The sorption isotherm of both in low and high concentrations of fluoride (F–) was investigated for selected calcination products. The sample calcined at 973K was found to show the highest sorption density for F– at equilibrium concentrations lower than 0.5mM, which was equivalent to the maximum concentration limit of F–. In this range, the principle of F– removal is mainly based on destructive hydration of MgO. At equilibrium concentrations of F– higher than 0.5mM, the sorption process was controlled by precipitation of CaF2 and co-precipitation with Ca(OH)2 due to excess liberation of Ca2 ions from CaO. In this concentration region the products of calcination at higher temperatures are profitable for the immobilization of F–. Additionally, the effect of CO2 gas derived from carbonates on the reactivity of MgO to remove F– during calcination of natural dolomite was also discussed.

Effect of fluoride on root resorption following heavy and light orthodontic force application for 4 weeks and 12 weeks of retention

To evaluate the null hypothesis that fluoride intake via drinking water has no effect on orthodontic root resorption in humans after orthodontic force application for 4 weeks and 12 weeks of retention. Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from two cities in Turkey. These cities had a high and low fluoride concentration in public water of ≥2 pm and ≤0.05 pm, respectively. The patients were randomly separated into four groups of 12 each: group 1HH, high fluoride (≥2 ppm) and heavy force (225 g); group 2LH, low fluoride (≤0.05 ppm) and heavy force; group 3HL, high fluoride and light force (25 g); and group 4LL, low fluoride and light force. Light or heavy buccal tipping force was applied on the upper first premolars for 28 days. At day 28, the left premolars were extracted (positive control side); the right premolars (experimental side) were extracted after 12 weeks of retention. The samples were analyzed with microcomputed tomography. On the positive control side, under heavy force application, the high fluoride groups exhibited less root resorption (P = .015). On the experimental side, it was found that fluoride reduced the total volume of root resorption craters; however, this effect was not statistically significant (P = .237). Moreover, the results revealed that under heavy force application experimental teeth exhibited more root resorption than positive control groups. The null hypothesis could not be rejected. High fluoride intake from public water did not have a beneficial effect on the severity of root resorption after a 4-week orthodontic force application and 12 weeks of passive retention.

Fluoride removal by adsorption on thermally treated lateritic soils

The ability of lateritic soils to remove fluoride from water has been studied. Important issues considered in the study include the relation between the mineral composition of soils and their ability to remove fluoride, the effect of thermal treatment of the soil on fluoride removal; the predominant fluoride containing species remain in the treated water and the possible mechanism of fluoride removal by lateritic soils. The fluoride removal capacity of thermally treated lateritic soils used in this study is in the range of 22 to 47 mmol/kg. The maximum capacity of 47 mmol/kg was obtained for RGS fired at 500 o C. The results obtained indicate that there is strong correlation between fluoride removal capacity and gibbsite content of the soil. From this it can be concluded that gibbsite is the active component in lateritic soils that strongly influence the fluoride removal capability. Speciation analysis reveals that at low initial fluoride concentrations the dissolution of gibbsite is facilitated by the adsorption of fluoride onto gibbsite. This may result in the formation of aluminum fluoro complexes in water. KEY WORDS : Fluoride removal, Laterite soils, Speciation analysis, Adsorption capacity, Thermal treatment Bull. Chem. Soc. Ethiop. 2012 , 26(3), 361-372. DOI: http://dx.doi.org/10.4314/bcse.v26i3.5

Preventing and treating white-spot lesions associated with orthodontic treatment: A survey of general dentists and orthodontists

The authors investigated the prevention and treatment of white-spot lesions (WSLs) during and after orthodontic therapy from the perspective of general dentists and orthodontists.The authors administered a cross-sectional survey to general dentists (n = 191) and orthodontists (n = 305) in Virginia, Maryland and North Carolina.Sixty-nine percent of general dentists and 76 percent of orthodontists recommended in-office fluoride treatment for patients with severe WSLs immediately after orthodontic treatment. Sixty-nine percent of general dentists reported that they had treated WSLs during the previous year, and 37 percent of orthodontists reported that they had removed braces because of patients' poor oral hygiene. Sixty percent of orthodontists referred patients with WSLs to general dentists for treatment. Eighty-five percent of orthodontists responded that they encouraged patients to use a fluoride rinse as a preventive measure. More than one-third of general dentists indicated that severe WSLs after orthodontic treatment could have a negative effect on their perception of the treating orthodontist.WSLs are a common complication of orthodontic treatment and their presence can result in a negative perception of the treating orthodontist by the patient's general dentist. Clinical implications. General dentists and orthodontists should work together to prevent the development of WSLs in their patients. Treatment with fluoride supplements and motivating and training patients to practice good oral hygiene will help achieve this goal. Treatment after debonding should include the topical application of low concentrations of fluoride.

Fluoride bioavailability in saliva during acute psychological stress

Abstract The aim of this study was to investigate the influence of acute stress on salivary fluoride bioavailability. Acute psychological stress was induced using a standardized model of public speaking. The saliva of male subjects was collected before and after the public speaking task and immediately, 10, 30, and 120 minutes after tooth brushing according to the Bass method with a dentifrice containing amine fluoride (AmF) or oral hygiene tablets containing sodium fluoride (NaF). Subjective psychological responses to public speaking were evaluated using the State-Trait Anxiety Inventory (STAI). Saliva cortisol levels were analyzed as an objective stress marker. The saliva secretion rate was measured both before and after public speaking. Saliva fluoride content was measured. Group comparisons were calculated using a univariate analysis of variance (ANOVA). In all analyses, the alpha-level was set at 0.05. Public speaking significantly increased state anxiety (p&lt;0.001) and salivary cortisol concentrations (p&lt;0.001). Acute stress did not influence salivary secretion rates. In the AmF group, stressed individuals exhibited statistically significant (p=0.044) lower fluoride concentration in saliva compared with the nonstressed subjects Acute psychological stress reactions do not cause hyposalivation but decrease fluoride bioavailability after using a dentifrice containing AmF. Fluoride bioavailability during acute stress is dependent on fluoride formulation.

Modified POF Sensor for Gaseous Hydrogen Fluoride Monitoring in the Presence of Ionizing Radiations

This paper describes the development of a sensor designed to detect low concentrations of hydrogen fluoride (HF) in gas mixtures. The sensor employs a plastic optical fiber (POF) covered with a thin layer of glass- like material. HF attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coated POF is obtained by means of low-pressure plasma-enhanced chemical vapor deposition that allows the glass-like film to be deposited at low temperature without damaging the fiber core. The developed sensor will be installed in the recirculation gas system of the resistive plate chamber muon detector of the Compact Muon Solenoid experiment at the Large Hadron Collider accelerator of the European Organization for Nuclear Research (CERN).

Hen egg yolk and skinned krill as possible foods for rearing leptocephalus larvae ofAnguilla japonicaTemminck &amp; Schlegel

Usual diets for rearing leptocephalus larvae of Japanese eel Anguilla japonica include eggs of the endangered spiny dogfish Squalus acanthias (SE). We investigated the effects of alternative food materials, hen egg yolk (HEY) and exoskeleton-free (skinned) Antarctic krill (SAK), on the growth and survival of eel larvae. We found that feed comprising whole krill including exoskeleton (WAK) containing higher levels of fluoride (37.89 mg kg−1) was acutely toxic to eel larvae exposed to this alone. In contrast, extract from SAK containing lower concentrations of fluoride (4.25 mg kg−1) showed no apparent adverse effects. Growth of larvae fed a mixture of SE and SAK in a feed trial of 58 days [mean body weight (BW), 6.0 mg] was about twofold higher than that of larvae fed a mixture of SE and WAK (3.2 mg) (P < 0.01). A mixture of HEY and SAK also had some dietary benefits for eel larvae, enabling them to survive for up to 58 days and to grow significantly (mean BW, 2.4 mg), compared with their initial weight (mean BW, 0.2 mg) (P < 0.001). Although additional nutritional improvements are needed, the present results suggest that combination diet HEY and SAK may be a good alternative to SE as an effective diet for eel larvae.

Molecular Mechanisms of Cytotoxicity and Apoptosis Induced by Inorganic Fluoride

Fluoride (F) is ubiquitous natural substance and widespread industrial pollutant. Although low fluoride concentrations are beneficial for normal tooth and bone development, acute or chronic exposure to high fluoride doses results in adverse health effects. The molecular mechanisms underlying fluoride toxicity are different by nature. Fluoride is able to stimulate G-proteins with subsequent activation of downstream signal transduction pathways such as PKA-, PKC-, PI3-kinase-, Ca2+-, and MAPK-dependent systems. G-protein-independent routes include tyrosine phosphorylation and protein phosphatase inhibition. Along with other toxic effects, fluoride was shown to induce oxidative stress leading to excessive generation of ROS, lipid peroxidation, decrease in the GSH/GSSH ratio, and alterations in activities of antioxidant enzymes, as well as to inhibit glycolysis thus causing the depletion of cellular ATP and disturbances in cellular metabolism. Fluoride triggers the disruption of mitochondria outer membrane and release of cytochrome c into cytosol, what activates caspases-9 and -3 (intrinsic) apoptotic pathway. Extrinsic (death receptor) Fas/FasL-caspase-8 and -3 pathway was also described to be implicated in fluoride-induced apoptosis. Fluoride decreases the ratio of antiapoptotic/proapoptotic Bcl-2 family proteins and upregulates the expression of p53 protein. Finally, fluoride changes the expression profile of apoptosis-related genes and causes endoplasmic reticulum stress leading to inhibition of protein synthesis.

Gum Containing Calcium Fluoride Reinforces Enamel Subsurface Lesions in situ

The aim of this study was to assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and a low concentration of fluoride (F) on the hardness of enamel subsurface lesions, utilizing a double-blind, randomized, and controlled in situ model. Fifteen individuals wore removable lingual appliances with 3 bovine-enamel insets containing subsurface demineralized lesions. Three times a day for 14 days, they chewed one of the 3 chewing gums (placebo, POs-Ca, POs-Ca+F). After the treatment period, cross-sectional mineral content, nanoindentation hardness, and fluoride ion mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS) were evaluated. Although there were no statistical differences in overall mineral content and hardness recovery rates between POs-Ca and POs-Ca+F subsurface lesions (p > 0.05), nanoindentation at 1-μm distance increments from the surface showed statistical differences in hardness recovery rate between POs-Ca and POs-Ca+F in the superficial 20-μm region (p < 0.05). Fluoride mapping revealed distribution of the ion up to 20 μm from the surface in the POs-Ca+F group. Nanoindentation and TOF-SIMS results highlighted the benefits of bioavailability of fluoride ion on reinforcement of the superficial zone of subsurface lesions in situ (NCT01377493).

Preliminary Assessment of Flourine Level of Spring and Stream Water in South West Nigeria

Four water samples from each of spring and stream in some locations across South-West, Nigeria, were analyzed for their fluoride levels and some other quality parameters. The samples coded 101, 202, 303, 404 representing spring water and 505, 606, 707, 808 representing stream water were analyzed for fluoride levels using Ion Selective Electrode method (ISE) while other quality parameters such as calcium, chloride, alkalinity, hardness and pH were determined using standard methods. The results obtained showed low fluoride concentrations of 0.15 ppm and 0.03 ppm in samples 101 and 202 respectively (spring water) while other water samples contained no traces of fluoride. These values are far below World Health Organization (WHO) limits of 1.50 ppm fluoride for drinking water. The water contained low calcium and chloride contents, ranging from 20.0 mg/l to 37.5 mg/l (hardness) indicating that the water is soft. pH values of between 5.6 and 6.0 were also obtained in contrast to 6.5-8.5 as stipulated in the World Health Organization guideline (WHO) for drinking water.

Anticaries effect of dentifrices with calcium citrate and sodium trimetaphosphate

Because of the growing concerns regarding fluoride ingestion by young children and dental fluorosis, it is necessary to develop new dentifrices.ObjectiveThe aim of this study was to evaluate the effect of dentifrices with calcium citrate (Cacit) and sodium trimetaphosphate (TMP) on enamel demineralization. Material and MethodsEnamel blocks (n=70), previously selected through surface hardness analysis, were submitted to daily treatment with dentifrices diluted in artificial saliva and to a pH-cycling model. The fluoride concentration in dentifrices was 0, 250, 450, 550, 1,000 and 1,100 µg F/g. CrestTM was used as a positive control (1,100 mg F/g). Cacit (0.25%) and TMP (0.25%) were added to dentifrices with 450 and 1,000 µg F/g. Surface hardness was measured again and integrated loss of subsurface hardness and fluoride concentration in enamel were calculated. Parametric and correlation tests were used to determine difference (p<0.05) and dose-response relationship between treatments. ResultsThe addition of Cacit and TMP did not provide a higher fluoride concentration in enamel, however it reduced (p<0.05) mineral loss when compared to other dentifrices; the dentifrice with Cacit and TMP and a low fluoride concentration presented similar results when compared to a dentifrice with 1,100 mg F/g (p>0.05). ConclusionsDentifrices with 450 and 1,000 µg F/g, Cacit and TMP were as effective as a gold standard one.

Effect of aluminum fluoride complexation on fluoride removal by coagulation

Effect of aluminum fluoride complexation on fluoride removal by Al salts coagulation was investigated by a series of batch experiments. Transformation of fluoride species in coagulation was studied by simultaneous determination of free fluoride and total fluoride at different pH and fluoride concentrations. Results showed that aluminum fluoride complexes dominated at low pH and high fluoride concentrations but more complexes did not represent higher fluoride removal. Comparison between coagulation with complexation and adsorption by Al(OH) 3 flocs was conducted and coagulation showed higher fluoride removal efficiency than adsorption in the pH range of 6.0–9.0. Titration test showed that Al F complexes were coprecipitated with less OH − than Al 3+. Characterization of FTIR and XPS also indicated that flocs after complexation was different from Al(OH) 3 flocs with or without fluoride. It was concluded that a new Al F OH coprecipitate formed in coagulation and fluoride was effectively removed by the coprecipitation.

Ingestion of Fluoride from Dentifrices by Young Children and Fluorosis of the Teeth - A Literature Review

The ADA recommends the use of fluoridated dentifrices as soon as the primary teeth erupt, so as to reduce the incidence of dental caries. However young children can ingest a significant amount of dentifrice during normal toothbrushing; this is a potential problem because the permanent teeth are at risk from fluorosis for the first seven years of life. the objective of this paper was to review the literature on the role of fluoride dentifrices in causing dental fluorosis. a search for literature was performed using MEDLINE, OVID with the key words fluorosis, dentifrice, ingestion, and children. The search was limited to English language publications. Subsequently, 31 articles were retrieved, additional relevant articles were collected from the references cited in the initially identified papers. Ultimately, 96 articles were retrieved for review. Fluoride, should be used with caution so that the benefits out-way the adverse affects. Oral health care providers need to systematically assess individual tooth brushing habits and emphasize the advantages of early use of a fluoridated dentifrice whilst still meeting the need for the prudent use of small quantities of dentifrice. Dentifrices with a low concentration of fluoride may be appropriate for young children who are considered to be at low caries risk and the risk of fluorosis is minimal for children who ingest this dentifrice; nevertheless, it appears that more research is still required on the therapeutic effects of fluoride dentifrices which contain fluoride at a low concentration.

Influence of Methionine and Vitamin E on Fluoride Concentration in Bones and Teeth of Rats Exposed to Sodium Fluoride in Drinking Water

Increased exposure to fluorine-containing compounds leads to accumulation of fluorides in hard tissues of bones and teeth, which may result in numerous skeletal and dental disorders. This study evaluates the influence of methionine and vitamin E on fluoride concentration in bones and teeth of rats subjected to long-term exposure to sodium fluoride in drinking water. The study was conducted in 30 3-month-old female Wistar FL rats. The animals were divided into five groups, six rats per group. The control group consisted of rats receiving only distilled water as drinking water. All other groups received NaF in the amount of 10 mg/kg of body mass/day in their drinking water. In addition, respective animal groups received: NaF + Met group--10 mg of methionine/kg of body mass/day, NaF + Met + E group--10 mg of methionine/kg of body mass/day and 3 mg of vitamin E (tocopheroli acetas)/rat/day and NaF + E group--3 mg of vitamin E/rat/day. Femoral bones and incisor teeth were collected for the study, and the fluoride concentration was determined using a fluoride ion-selective electrode. Fluoride concentration in both bones and teeth was found to be higher in the NaF and NaF + Met groups compared to the control group. In groups NaF + Met + E and NaF + E, the study material contained much lower fluoride concentration compared to the NaF group, while the effect was more prominent in the NaF + E group. The results of the studies indicate that methionine and vitamin E have opposite effects on accumulation of fluorides in hard tissue in rats. By stimulating fluoride accumulation, methionine reduces the adverse effect of fluorides on soft tissue, while vitamin E, which prevents excessive accumulation of fluorides in bones and teeth, protects these tissues from fluorosis. Therefore, it seems that combined application of both compounds would be optimal for the prevention of the adverse effects of chronic fluoride intoxication.

The effect of fluoride on orthodontic tooth movement in humans. A two- and three-dimensional evaluation

Abstract Aims: The aim of the present study was to determine whether high and low fluoride concentrations in drinking water affected the early stages of tooth movement when heavy and light orthodontic forces were applied for 4 weeks. A further aim was to compare and evaluate the resulting two-dimensional (2-D) and three-dimensional (3-D) orthodontic tooth movement. Methods: The sample consisted of 96 maxillary upper first premolars from 48 patients who required premolar extractions as part of their orthodontic treatment. Patients were selected from two different cities in Turkey with low and high fluoride concentrations of 0.05 and 2 ppm, respectively. The patient sample was divided into four groups according to the magnitude of force applied to the first premolars and the concentration of fluoride in the public water supply; Group 1, High fluoride intake (≥ 2 ppm)-Heavy force (225 g); Group 2, Low fluoride intake (≤ 0.05 ppm)-Heavy force; Group 3, High fluoride intake-Light force (25 g); and Group 4, Low fluoride intake-Light force. A light or heavy buccal tipping orthodontic force was applied to the upper first premolars for 4 weeks. The first three palatal rugae were used for the superimposition of patient casts in a 2-D and 3-D evaluation of generated movements. Results: It was found that heavy force application and fluoride intake increased the average rate of tooth movement. It was further shown that age was negatively correlated with tooth movement in the 2-D and 3-D measurements. Conclusions: The average rate of tooth movement was found to be greater in the heavy force and high fluoride intake group (Group 1HH). Age was negatively correlated with orthodontic tooth movement. Two- and three-dimensional methods were accurate for the assessment of tooth movement after four weeks of buccal tipping force application when the palatal rugae were used for superimposition.

Physical properties of root cementum: Part 20. Effect of fluoride on orthodontically induced root resorption with light and heavy orthodontic forces for 4 weeks: A microcomputed tomography study

The major side effect of orthodontic treatment is orthodontically induced inflammatory root resorption. Fluoride was previously shown to reduce the volume of the root resorption craters in rats. However, the effect of fluoride on orthodontically induced inflammatory root resorption in humans has not yet been investigated. The aim of this study was to investigate the effect of high and low amounts of fluoride intake from birth on orthodontically induced inflammatory root resorption under light (25 g) and heavy (225 g) force applications. Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from 2 cities in Turkey with high and low fluoride concentrations in the public water of ≥ 2 and ≤ 0.05 ppm, respectively. The patients were randomly separated into 4 groups of 12 each: group 1, high fluoride intake and heavy force; group 2, low fluoride intake and heavy force; group 3, high fluoride intake and light force; and group 4, low fluoride intake and light force. Light or heavy buccal tipping orthodontic forces were applied on the maxillary first premolars for 28 days. At day 28, the teeth were extracted, and the samples were analyzed with microcomputed tomography. Fluoride reduced the volume of root resorption craters in all groups; however, this effect was significantly different with high force application (P = 0.015). It was also found that light forces caused less root resorption than heavy forces. There was no statistical difference in the amount of root resorption observed on root surfaces (buccal, lingual, mesial, and distal) in all groups. However, the middle third of the roots showed the least root resorption. With high fluoride intake and heavy force application, less root resorption was found in all root surfaces and root thirds. Fluoride may reduce the volume of root resorption craters. This effect is significant with heavy force applications (P <0.05). The cervical and apical thirds of the root showed significantly greater root resorption after the application of buccal tipping force for 4 weeks.

Fabrication parameter-dependent morphologies of self-organized ZrO2 nanotubes during anodization

Zirconia (ZrO2) nanotubes have been synthesized using a facile anodizing process in organic electrolyte systems containing a low content of fluoride. The nanotube architecture evolution was recorded at different anodization periods (1–24 h) by scanning electron microscopy. A compact layer was found between the Zr substrate and its upper tubular layer after 1 h of anodization, whereas after further anodization for 3 h the compact layer disappeared. Meanwhile, ZrO2 nanotubes turned to a uniform structure from top to bottom. However, after 18–24-h-long anodization, the uniform tubular layer was replaced by a random layer composed of various structural defects. Since the compact layer was not completely dissolved, the retained compact layer yielded O-rings with double walls on the outer surface of the nanotubes.