Efficacy of fluoride varnishes for preventing enamel demineralization after interproximal enamel reduction. Qualitative and quantitative evaluation

Comparison of near-infrared imaging with cone-beam computed tomography for proximal caries detection in permanent dentition: An in vivo study

OBJECTIVES

This study aimed to evaluate the diagnostic performance of near-infrared imaging (NIRI) and unaided visual examination (UVE) in detecting proximal caries in permanent dentition in comparison with cone-beam computed tomography (CBCT).

METHODS

Patients who underwent NIRI, UVE, and CBCT imaging within 1 week were enrolled. Using CBCT as the reference test, the positive percent agreement (PPA), negative percent agreement (NPA), and overall percent agreement (OPA) of NIRI, UVE, and a combination of the two for detecting proximal caries at different depths and in different tooth locations were assessed. Additionally, the consistency of these diagnostic methods with CBCT was evaluated.

RESULTS

We evaluated 6,084 proximal surfaces and identified 177 CBCT-positive sites. NIRI had a PPA, NPA, and OPA of 68.93 %, 99.09 %, and 98.21 %, respectively, with a substantial agreement with CBCT. When combined with UVE, the PPA increased by approximately 50 % compared with that of UVE alone. Regarding caries at different depths, NIRI outperformed UVE in detecting initial caries (ICDAS 1-2) over moderate-to-advanced caries (ICDAS 3-6). However, the combined use of NIRI and UVE improved the detection of moderate-to-advanced caries. In the anterior teeth region, NIRI exhibited excellent agreement with CBCT, surpassing its performance in the posterior region.

CONCLUSIONS

Although NIRI cannot fully replace radiographic methods, the substantial agreement of NIRI with CBCT in detecting proximal caries highlights its potential as a complementary tool in routine caries screening, especially when combined with UVE.

CLINICAL SIGNIFICANCE

This study highlights the potential of NIRI as a radiation-free method for detecting proximal caries in permanent teeth. Early detection through regular NIRI scanning can lead to timely intervention, improved patient outcomes, and reduced overall disease burden.

Does surface enamel composition and characteristics vary with inter proximal enamel reduction?

OBJECTIVE

This study aimed to evaluate the chemical composition of the proximal enamel surface and the surface characteristics subjected to different extents of interproximal reduction (IPR) in a clinical setting.

MATERIALS AND METHODS

Premolars of orthodontic patients which were designated for extraction were subjected to .2 mm, .3 mm, and .5 mm of IPR. After 1 month, the teeth were extracted and the teeth were subjected to scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX).

RESULTS

The SEM images of the three experimental groups (taken at magnification of 500 × and 2000 ×) showed that the enamel surfaces were irregular and rough compared to the honey comb appearance of the unstripped group. Small areas of erosion of enamel surface were seen in Group I (0.2 mm) under 2000 × magnification compared to Group IV (control) which showed typical arrangement of enamel rods in alternating orientation. The enamel surfaces of stripped and unstripped enamel contained calcium, phosphorus, carbon, oxygen, and nitrogen. The differences were not statistically significant and neither were the calcium phosphorous stoichiometric ratios between the four groups.

CONCLUSIONS

On analyzing the surface characteristics of enamel using SEM between the stripped and unstripped surfaces, there were irregularities and roughness seen in stripped surface whereas honey comb pattern was observed in unstripped enamel surfaces. The elements found in unstripped and stripped enamel surfaces were calcium, phosphorous, carbon, oxygen, and nitrogen. Although the calcium and phosphorus were high in the 0.5 mm IPR group, the difference between stripped and unstripped enamel surfaces was statistically not significant.

CLINICAL RELEVANCE

There have been concerns that IPR can remove the superficial mineral-rich layer making the deeper layers more susceptible to carious attack. No study has evaluated the mineral content in different layers of enamel in response to IPR in vivo and this study found no significant difference between pristine enamel and enamel subjected to IPR. The results of this study strengthen the validity of the clinical protocol employed.

Efficacy of Nano Silver Fluoride and/or Diode Laser In Enhancing Enamel Anticariogenicity around orthodontic brackets

PURPOSE

This in vitro study aimed to compare the anticariogenic effect of using diode laser irradiation and/or nano silver fluoride varnish around orthodontic brackets.

MATERIALS AND METHODS

60 caries-free and intact premolars were randomly divided into 3 experimental groups as follow: (1) Group I (nano silver fluoride treated group, n = 20), (2) Group II (diode laser treated group, n = 20) and (3) Group III (combined nano silver fluoride and diode laser treated group, n = 20). Anticariogenicity was assessed using polarized light, scanning electron microscope, elemental and shear bond strength analyses.

RESULTS

PLM and SEM showed presence of few demineralized areas in group I. Group II revealed a dramatic increased demineralization. Group III disclosed almost typical homogenous surface enamel. elemental analysis showed a highly significant difference between Group III and II and a significant difference between Group III and I. Shear bond strength analysis revealed a significant difference between group I and II and between group III and II. The difference between group III and I was non-significant.

CONCLUSION

Both diode laser and nano silver fluoride positively affected dental enamel with the most superior enhancement in enamel criteria was achieved by surface pretreatment by combined nano silver fluoride varnish and diode laser irradiation.

Evaluation of the enamel nano-topography influenced by different techniques of interproximal reduction: An atomic force microscopic study

Introduction:

Interproximal enamel reduction is a part of the orthodontic treatment as a method of space generation in addition to other vast indications. Some studies found that different techniques might impose changes to the enamel surface that alter its topography, which in turn might influence its integrity and susceptibility to caries. Polishing, however, after this procedure is thought to be helpful to reduce these adverse effects.

Aim:

To evaluate the nano-topography of the enamel surfaces after interproximal reduction (IPR) and determine its influence on enamel surface roughness and examine the need for polishing to minimise these influences, when combined with topical fluoride application.

Methods:

A total of 60 proximal surfaces of 40 extracted maxillary premolars (10 premolars left unprepared as the control group) were reduced with different stripping instruments (discs, burs and manual strip system). The surface roughness of enamel was analysed with an atomic force microscope to determine the results quantitatively as well as qualitatively on the nanoscopic scale. One of each proximal surface was followed by polishing and fluoride varnish after the reduction.

Results:

The results showed that surface roughness was increased in all groups without polishing. The greatest mean roughness was recorded for the disc group (212 ±125.7), followed by the bur group (172 ±93.1) and manual strips (153.8±106.7). The difference between the groups, however, was not significant for both mean roughness ( P = 0.656) and height ( P = 0.737). The parameters were decreased after polishing in all groups but the difference between methods was not significant for both parameters ( P = 0.946 and P = 0.849); however, the mean height was reduced to nearly half the reading in the bur and manual strip method. The disc group only showed a statistically significant decrease in surface roughness with polishing ( P < 0.05). All other results were not significant.

Conclusion:

All methods of interproximal reduction do not influence enamel surface nanotopography significantly with and without polishing. Polishing resulted in significant reduction of surface roughness only in the disc group.

Fluoride varnish, ozone and octenidine reduce the incidence of white spot lesions and caries during orthodontic treatment: randomized controlled trial

This randomized, parallel, controlled trial assessed the effect of fluoride varnish, ozone and octenidine on white spot lesions (WSLs) and caries during orthodontic treatment. Patients were enrolled between 1st September 2017 and 31st August 2020 at initiation of orthodontic treatment in Department of Interdisciplinary Dentistry Pomeranian Medical University in Szczecin, Poland. All participants were randomly assigned to four study and one control groups using number random generator. However, investigators were not blinded due to the nature of the study. Groups I, II, III, IV had professional cleaning and varnishing (5% NaF) every 4 weeks. Groups II and IV had in-office ozone therapy before varnishing, groups III and IV received domestic octenidine mouthrinse. Group K had no professional hygienic or prophylactic procedures. WSLs were assessed at T0 and then every 4 weeks (T1-T4) and caries-at T0 and T4. The specific objective was to assess the influence of fluoride varnish, ozone and octenidine on the incidence of white spot lesions and caries during orthodontic treatment. The primary outcome of this report was the highest number of WSLs in group K and the lowest percentage of patients with WSLs in group IV. Each group comprised 30 randomized participants; they were all analyzed. No WSLs were found at T0, but they were stated in all groups at T4. The numbers of patients with WSLs significantly increased between T0-T4 in groups I and K. Group IV had the lowest percentage of patients with WSLs in T1-T4. WSLs in group IV were found no earlier than at T2. Group K had the highest percentage of WSLs at T4: 26%. At T0 all the groups had DMFs above 0 with a significant increase at T4. No side effects of the introduced prophylaxis were observed in any group. Caries is an important problem of fixed orthodontic treatment. Even an extremely intensive prophylaxis could not completely prevent WSLs and caries. Simultaneous application of fluoride varnish, ozone gas exposure and octenidine appears to have a beneficial effect in limiting the development of WSLs.Trial registration: NCT04992481.

Comparative Evaluation of Influence of Nd:YAG Laser (1064 nm) and 980 nm Diode Laser on Enamel around Orthodontic Brackets: An In Vitro Study

(1) Background: The prevention of demineralizing lesions at the enamel structure level continues to represent a challenge in daily dental practice. When bacteria influence the pH level, this will decrease below the threshold for remineralization and the dissociation of hydroxyapatite will occur with a high percentage of phosphate and calcium loss. These elements continue to be studied by many authors in order to obtain a working protocol that will lead to their stabilization at the level of the enamel structure, thus preventing the demineralization process. The aim of this study is to evaluate and compare the influence of two types of laser wavelengths on the surface morphology and mineral components of the enamel through an examination with scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX). (2) Methods: Thirty permanent human incisors extracted for periodontal reasons from patients aged 25−40 years old were selected for this study. Metallic brackets (SS Standard 022 Slot, OC Orthodontics, McMinnville, OR, 97128, USA) were bonded onto each tooth. The buccal surface was randomly assigned three sections: Section A—negative control (no treatment), section B—treated with 980 nm Gallium−Aluminum−Arsenide diode laser (a 300 µm optic fiber was used with 0.8 W output power, energy density of 5.33 J/mm2, in continuous mode, for 30 s, oriented perpendicularly to the enamel surface in contact mode) (KaVo GENTLEray 980 Diode Laser, Kaltenbach & Voigt GmbH, Biberach, Germany), and section C—treated with Nd:YAG laser (a 300 µm fiber was carried out at a 1 mm distance from the enamel surface with 0.75 W power, 75 mJ pulse energy, pulse repetition rate of 10 Hz, 5 J/mm2 fluency, average exposure time of 30 s, and water cooling assisted) (LIGHTWALKER AT S, M021-5AF/1 S, Fotona d.o.o, Ljubljana, Slovenia). The elements evaluated in this study were calcium (Ca), phosphate (P), oxygen (O), and carbon (C). A one-way analysis of variance, paired t-tests, and independent t-tests were carried out to evaluate the results using the SPSS 19 IBM Statistical package software for Microsoft. (3) Results: The evaluation of the data indicated that both wavelengths produced an increase in Ca wt% (for diode laser the mean of Ca wt% before irradiation was 21.06, while that after treatment reached 28.24; and for Nd:YAG laser, the mean of Ca wt% before irradiation was 21.31, while that after treatment reached 33.88); as well, the 980 nm diode laser decreased P wt% (from 17.20 before irradiation to 16.92 after irradiation) and the Nd:YAG laser increased P wt% (from 17.46 before irradiation to 18.28 after irradiation). These results showed a statistically significant difference at the p < 0.05 level. (4) Conclusions: It can be concluded that the best improvement of enamel chemical composition was obtained with Nd:YAG irradiation.

Effectiveness of a toothpaste and a serum containing calcium silicate on protecting the enamel after interproximal reduction against demineralization

To evaluate the effectiveness of a calcium silicate/phosphate fluoridated tooth paste and a serum compared with a toothpaste containing hydroxyapatite on protecting the enamel after interproximal reduction against demineralization. 3 sets of eleven incisors were created. The teeth underwent interproximal enamel reduction (IER) of 0.5 mm. Each set was allocated to one of three groups: (1) Brushing without toothpaste (control group); (2) Vitis toothpaste + Remin Pro; (3) Regenerate toothpaste + Regenerate Serum. The agents were applied three times a day and specimens subjected to demineralization cycles for 30 days. The weight percentages of calcium (Ca) and phosphorous (P) were quantified by X-ray microfluorescence spectroscopy. Surface microhardness measurements and electron scanning microscopy (SEM) observations were made. Ca data and the Ca/P ratio were significantly higher in Group 3 than the other groups (p < 0.017), while P was significantly lower in Group 3 (p < 0.017). No significant differences were found between Groups 1 and 2 (p > 0.017). Group 3 showed significantly higher microhardness values (p < 0.05) than Group 1. No significant differences were found for other comparisons between groups (p < 0.05). SEM images showed less demineralization in Group 3. The application of a calcium silicate/phosphate fluoridated tooth paste (Regenerate advance) and a dual serum (Regenerate advance enamel serum) protect the enamel with interproximal reduction against demineralization. Therefore, this treatment could be used to prevent the dissolution of hydroxyapatite after IER.

Effect of dentin and fiber post surface treatments with fumaric acid on the bonding ability of fiber posts

This study investigated the effects of fumaric acid on push-out bond strength when applied to dentin surfaces and fiber posts. The root canals of 60 mandibular premolar teeth were instrumented and obturated. After removing two thirds of filling material, teeth were prepared according to six randomized groups (n = 10/group) defined by two fiber post surface treatments (0.7% fumaric acid or 9% hydrofluoric acid) and three dentin conditioning treatments [control (no conditioning); 17% ethylenediamine tetraacetic acid (EDTA); or 0.7% fumaric acid]. After fiber post-cementation, three 1-mm thick discs were obtained from each tooth by transverse sectioning, and each disc underwent push-out bond strength testing. Data were analyzed with a one-way analyses of variance (anova) and t tests; p < .05 was considered statistically significant. Failure modes were determined by stereomicroscopy, and the surface characteristics of dentin and fiber posts were observed by scanning electron microscopy. Push-out bond strength was greater for the group in which the post surface treated with hydrofluoric acid and the dentin surface treated with fumaric acid than the nontreated dentin and hydrofluoric acid-treated post group (p < .05). There were no significant differences between other comparison pairs (p > .05). A combination of fumaric acid dentin conditioning and hydrofluoric acid fiber post treatment strengthened the bonding ability of fiber posts.

Depth of acid penetration and enamel surface roughness associated with different methods of interproximal enamel reduction

Objectives

To assess and compare the enamel surface quality after interproximal enamel reduction (IPR) was performed with different systems and to study the relation between acid penetration depth and enamel surface quality as well as the importance of remineralization.

Methods

Sixty-five extracted teeth were randomly allocated to five experimental groups: untreated control, manual with New Metal Strips, mechanical with oscillating segment (OS) discs, Safe-Tipped Bur Kit, and the Ortho-Strip, followed by 30 s of polishing with the Softflex system and the Compo-system after treating the tooth with OS discs. Mesial surfaces were demineralized for 24 h and distal surfaces were subjected to interchanging demineralization and remineralization cycles of 24 h each for 18 days. The analysis was carried out by profilometry, scanning electron microscopy, and polarization microscopy.

Results

After IPR and polishing, enamel roughness was reduced for all systems tested except for the Essix Safe-Tipped Bur Kit. Subsequent demineralization increased enamel roughness in all groups except controls beyond the original level prior to IPR except for IPR with New Metal Strips or Ortho-Strips and subsequent polishing. Cyclic demineralization and remineralization for 18 days yielded a reduction in acid penetration depth and an increase in surface smoothness, which correlated with each other only for controls and treatment with New Metal Strips or Ortho-Strips.

Conclusions

Manual IPR, using New Metal Strips and, even more, the oscillating IPR system Ortho-Strips, yielded smoother interproximal enamel surfaces and less acid penetration depth than the IPR systems with OS discs and the Safe-Tipped Bur Kit after polishing and 18 days of cyclic demineralization and remineralization. Irrespective of the IPR procedure, proper remineralization of IPR-treated surfaces is advisable to reduce caries susceptibility.

Microleakage of conventional light-cure resin-based fissure sealant and resin-modified glass ionomer sealant after application of a fluoride varnish on demineralized enamel

BACKGROUND

International guidelines on the prevention of caries recommend sealing of the pits and fissures of the permanent molars. There is no evidence on which type of material is most effective on demineralized enamel.

AIM

To evaluate the microleakage of a conventional light-cured, resin-based fissure sealant (LCRBS), GrandiO Seal, and a resin-modified glass ionomer sealant (RMGIS), Vitremer, after application of a fluoride varnish, Bifluorid 12, on demineralized enamel.

DESIGN

80 human third molars were divided into eight groups. The groups combined the three study factors (1) type of enamel (intact or demineralized); (2) enamel non-varnished or varnished with Biflourid12; and (3) type of sealant (GrandiO Seal or Vitremer). The percentage of microleakage after thermocycling was measured using imaging analysis software. The Kruskal-Wallis plus Dunn tests were used to compare differences in microleakage in the different groups.

RESULTS

The lowest microleakage was in the unvarnished groups, and was the same for GrandiO Seal and Vitremer. When varnish was applied, microleakage was greater in demineralized enamel than in intact enamel for both LCRBS and RMGIS.

CONCLUSION

The application of fluoride varnish on demineralized enamel increases the microleakage of both GrandiO Seal and Vitremer.

Enamel Resistance to Demineralization After Bracket Debonding Using Fluoride Varnish

The aim of this study was to evaluate the elemental content and morphology of enamel subjected to demineralization cycles after bracket debonding, adhesive remnant removal, and application of a fluoride varnish. 125 bovine teeth were divided into five groups (n = 25): 1) Intact enamel; 2) Intact enamel + demineralization cycles (DC); 3) Enamel after adhesive removal; 4)Enamel after adhesive removal + DC; 5) Enamel after adhesive removal + Profluorid + DC. The weight percentages of calcium (Ca), phosphorous (P) and fluoride (F) were calculated using energy dispersive X-ray spectroscopy (EDX). Samples were observed under scanning electron microscopy (SEM). Data were analyzed using Kruskal-Wallis and Mann-Whitney test. The weight percentages of Ca and P in Group 1 were significantly higher than Groups 2, 4, and 5. The weight percentages of Ca and P in Group 2 were significantly higher than Groups 4 and 5. Group 3 presented significantly higher percentages of Ca and P than Group 4. Group 5 showed a significantly higher percentage of Ca than Group 4. The presence of F was detected in Group 5. SEM images showed more signs of demineralization in Group 4 than Group 5. Fluoride varnish application may protect enamel from demineralization after bracket debonding.