In vivo inhibition of demineralization around orthodontic brackets

Debonding Characteristic and Survival Probability of Adhesive Flash-Free Ceramic Orthodontic Brackets Following pH Cycling

OBJECTIVES

 Orthodontic bracket bond failure is an obstacle in clinical orthodontics. This study investigated the influence of pH cycling on the shear bond strength (SBS), adhesive remnant index (ARI), and survival probability of adhesive-precoated flash-free ceramic brackets.

MATERIALS AND METHODS

 Forty mandibular premolars were randomly divided into two groups (n = 20): C: noncoated orthodontic brackets, and F: flash-free adhesive-precoated orthodontic brackets. Each group was subdivided into two subgroups according to storage medium solutions (n = 10): in subgroup AS, specimens were immersed in artificial saliva for 24 hours, and in Subgroup ASL, specimens were recycled between a demineralizing solution and an artificial saliva for 42 days. Within each subgroup, specimens were subjected to SBS and ARI testing. SBS data were analyzed using one-way ANOVA (analysis of variance) and Tukey's post-hoc test. Weibull analysis was performed on the SBS data to determine the characteristic SBS and their survival probabilities.

RESULTS

 Flash-free adhesive-precoated brackets had higher significant (p < 0.001) SBS values in both the AS group (17.74 ± 1.74 MPa) and the ASL group (12.61 ± 1.40 MPa) compared with the noncoated bracket (10.67 ± 1.55 and 7.89 ± 1.39 MPa, respectively). The ARI scores for the noncoated brackets in the AS group were 70% occurrence for score 1, while 90% for score 1 in the ASL group. For the flash-free precoated brackets, ARI scores were 70% occurrence for score 2 in the AS group, while 80% for score 2 in the ASL group. Flash-free brackets had higher SBS in both AS and ASL groups (14.07 and 9.76 MPa, respectively), at 95% survival probability.

CONCLUSION

 Flash-free orthodontic brackets performed better in terms of significantly higher bond strength and higher ARI scores. Meanwhile, noncoated brackets revealed acceptable SBS results in both storage medium groups. Flash-free brackets showed higher survival than the noncoated brackets in both storage medium groups at 90% survival probability.

In vivo comparison of initial caries lesions using the enamel decalcification index and quantitative light-induced fluorescence measurement during orthodontic therapy

OBJECTIVES

To compare two quantitative assessment methods - visual-tactile examination and fluorescence measurement - for detecting of initial caries lesions in adolescents undergoing treatment with a multibracket appliance (MB).

MATERIALS AND METHODS

This study included 28 subjects (14 males, 14 females), treated with MB in both the maxilla and mandible. Data collection occurred at three times points: prior to treatment (T0), six months after MB insertion (T1), and one year post-insertion (T2). The Enamel Decalcification Index (EDI; 0-3 scale) and quantitative light-induced fluorescence (QLF) were employed for assessment.

RESULTS

At T0, four subjects (14%) exhibited no lesions, while only two (7%) remained lesion-free at T1, and again at T2. The kappa coefficient for agreement between the two diagnostic methods across all time points was 0.71.

CONCLUSIONS

Both the QLF and EDI methods yielded similar results, with only minor discrepancies. To determine the most appropriate method for each individual case, considerations of cost, benefit and time should be made.

CLINICAL RELEVANCE

The similarity in outcomes for the QLF and EDI methods indicates that both diagnostic methods are effective and reliable. However, QLF may be prone to interference, which must be accounted for during its application.

Laser-assisted Icon and clinpro for restoring white spot lesions: an in vitro comparative study

Managing white spot lesions (WSLs) remains a challenging issue that has yet to be fully resolved. WSLs are areas of demineralized enamel that most commonly occur following orthodontic treatments. They can potentially lead to enamel caries and are also esthetically undesirable. The current study investigated and analyzed the effects of Icon resin infiltration (Icon) and Clinpro XT varnish (Clinpro), both alone and in combination with a diode laser, on the restoration of WSLs. Color change, microhardness, and scanning electron microscopy were used to evaluate the WSLs after the different treatment applications. Results showed that the combination of Icon and Clinpro, along with a diode laser, enhanced color stability and restoration of enamel hardness in white spot lesions. Utilizing a diode laser significantly improved the efficacy of both Icon and Clinpro therapies. SEM examination verified that laser-assisted treatments resulted in almost total blockage of enamel rods, indicating enhanced effectiveness. Conclusions: Integrating diode laser treatment with Icon and Clinpro XT Varnish has significantly improved the esthetic outcomes and mechanical properties of treated enamel.

Physical, mechanical and antibacterial properties of the orthodontic adhesive doped with S-TiO2

Orthodontic adhesive doped with sulfur-modified TiO2 promotes antibacterial effect. The objective of the study was to characterize the physical, mechanical and antibacterial properties of the orthodontic bracket adhesive, doped with modified titanium dioxide nanoparticles. Sulfur-doped TiO2 was synthetized and morphological topography was analyzed with TEM and SEM imaging. The catalytic performance during the degradation of rhodamine B was assessed. Nanomaterial was added at four concentration (1, 3, 6, and 10 wt%) to a commercial orthodontic adhesive. The shear bond strength and microhardness of a resin-based orthodontic adhesive containing S-TiO2 were evaluated. The inhibitory effect of the pure and doped adhesives against Escherichia coli and Streptococcus mutans was examined. As the results, the highest antimicrobial activity and good adhesive properties were noticed for light-cured orthodontic adhesive doped with 3% of S-TiO2. In this case, orthodontic adhesives with strong and long-lasting bactericidal properties can be created through the incorporation of modified TiO2 without negatively influencing microhardnesses, and bonding ability. White spot lesion and demineralization, which occurs very often in patients during orthodontic treatment, can be therefore minimized.

Preparation and performance evaluation of a novel orthodontic adhesive incorporating composite dimethylaminohexadecyl methacrylate-Polycaprolactone fibers

This study addressed enamel demineralization, a common complication in fixed orthodontic treatment, by evaluating a novel orthodontic adhesive with DMAHDM-PCL composite fibers. These fibers, produced through electrospinning, were incorporated into orthodontic adhesive to create experimental formulations at different concentrations and a control group. The study assessed antimicrobial properties, biosafety, and mechanical characteristics. New orthodontic adhesive exhibited significant bacteriostatic effects, reducing bacterial biofilm activity and concentrations. Incorporating 1% and 3% DMAHDM-PCL did not affect cytocompatibility. Animal tests confirmed no inflammatory irritation. Shear bond strength and adhesive residual index results indicated that antimicrobial fibers didn't impact bonding ability. In conclusion, orthodontic adhesives with 3% DMAHDM-PCL fibers are potential antimicrobial bonding materials, offering a comprehensive solution to enamel demineralization in orthodontic patients.

Effect of Fluoride-releasing Resin Cement on the Development of White Spot Lesions Around Orthodontic Brackets - A Retrospective Study

AIMS

This study aimed to assess the effect of G-CEM, a fluoride-releasing cement, on the development of white spot lesions (WSLs) and their severity around orthodontic brackets.

METHODS AND MATERIALS

This case-control study was conducted by reviewing 140 dental records of fixed orthodontic patients presenting to an orthodontic clinic. The patients were assigned to two groups ( n = 70). In group 1, Transbond XT resin cement, and in group 2, G-CEM had been used for bracket bonding. The frequency and severity of WSLs in each group were evaluated by assessing the available post-treatment photographs of patients and notes left by their orthodontist in their records in this regard. The number of teeth with WSLs in each patient was recorded, and the severity of lesions was categorised by Gorelick's analysis.

STATISTICAL ANALYSIS

Comparisons were made using independent t -test, Wilcoxon test and Mann-Whitney test (alpha = 0.05).

RESULTS

In both the maxilla and mandible, the prevalence of WSLs was significantly higher in the Transbond XT group than in the G-CEM group ( P = 0.01). The difference in frequency of WSLs between the maxilla and mandible was not significant within each group ( P > 0.05). Tooth #22 had the highest frequency of WSLs (11.4%) in the Transbond XT group, while teeth #12 and #36 had the highest frequency of WSLs (2.9%) in the G-CEM group. The difference in frequency of WSLs was not significant between males and females ( P > 0.05).

CONCLUSION

Bracket bonding with G-CEM fluoride-releasing cement significantly reduced the development of WSLs around orthodontic brackets.

Effect of adhesive components in experimental fluoride varnish on fluoride release within 30 days in vitro study

We aimed to determine whether adhesive components could increase the release time of effective fluoride concentration from an experimental fluoride varnish applied to bovine teeth. An experimental fluoride varnish containing 5% sodium fluoride (EX1) was prepared and combined with 35% hydroxyethyl methacrylate (HEMA) (EX2), 5% glutaraldehyde (EX3), or 35% HEMA/5% glutaraldehyde mixture (EX4). Two commercially available fluoride varnishes were used for comparison. Each group was applied to bovine incisors, and the fluoride release and pH were monitored for 30 days. Cell viability analysis, scanning electron microscopy, and energy-dispersive spectroscopy were performed. EX4 released the highest and most effective concentration of fluoride for the longest period and reached neutral pH at the earliest; the release was maintained for up to 30 days without cytotoxicity. In conclusion, EX4 is considered to be the most effective varnish to prevent dental caries.

In-vitro effect of a single application of CPP-ACP pastes and different fluoridated solutions on the prevention of dental caries around orthodontic brackets

OBJECTIVE

To assess the in-vitro effect of single applications of CPP-ACP pastes and different fluoridated solutions on the prevention of dental caries around orthodontic brackets.

MATERIAL AND METHODS

Tooth/bracket sets (n=65) were immersed in artificial saliva (1h at 37ºC) and randomly subjected to single applications (100µL; 1min) of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP emulsion), CPP-ACP with fluoride (CPP-ACPF emulsion), solutions of titanium tetrafluoride (TiF4) or sodium fluoride (NaF), or no treatment (CG). Multispecies biofilm (5 x 105 CFU/mL) was formed in the presence of 2% sucrose. After 24 h, the pH and the concentration of total soluble fluoride (TSF) were analyzed by culture medium. The presence of active white spot lesions (WSL) evaluated by macroscopic examination and the percent surface mineral loss (%SML) were analyzed. Also, the topography of enamel was detected by analysis of scanning electron microscopy (SEM). The data was assessed by chi-square, Kruskal-Wallis, and Mann-Whitney tests (p < 0.05).

RESULTS

Fluoride-containing compounds led to a smaller pH reduction than did CPP-ACP and CG (p<0.05). There was difference in TSF between the groups (p<0.05), denoted as TiF4> NaF > CPP-ACPF > CPP-ACP > CG. Regarding the presence of WSL and %SML, the NaF group obtained lower values (p<0.05), while TiF4 and CPP-ACPF were similar (p>0.05). SEM demonstrated that fluoride-free groups had a larger surface dissolution.

CONCLUSION

Fluoridated groups including solutions and CPP-ACPF were more effective than CPP-ACP in reducing enamel demineralization around orthodontic brackets after a single application.

Effects of topical fluoride on primary tooth enamel microhardness after diode laser treatment

Objectives

Tooth decay is controlled and prevented using fluorides. Specifically, a combination of laser irradiation and topical fluoride application can improve fluoride absorption. Although laser irradiation is recommended in traditional technology for caries prevention, little is known about the efficacy of caries-inhibiting laser diodes. Further, most studies have focused on permanent teeth. The objective of this study was to explore the effect of laser diode radiation mixed with topical fluoride on the enamel surface microhardness of primary teeth.

Material and method

The 60 primary teeth were divided into 60 plates. Baseline Vickers microhardness was established for each enamel surface. The samples were then divided into three groups. 4 % NaF varnish (group A) and 4 % NaF varnish using diode 2 and 3 W lasers (groups B and C, respectively). The final microhardness was measured and statistically evaluated using SPSS version 16. ANOVA was used to compare the means of the tested groups, which had a P-value of 0.05, indicating significance.

Result

The mean and standard deviation of microhardness for the different groups was tested. Group C (4 % NaF with a diode laser at 3 W) showed a higher average Vickers hardness (VHN) than Group B (4 % NaF with a diode laser at 2 W), whereas group A showed the lowest average VHN. There was a significant difference in microhardness between groups (P 0.05).

Conclusion

This study explored the effect of laser mixed with topical fluoride on enamel surface microhardness of primary teeth. The use of a diode laser (Quanta System, Italy) with a fluoride varnish applied to the enamel surface has a greater effect on the resistance of the enamel to caries.

Effect of Fluoride Release on Enamel Demineralization Adjacent to Orthodontic Brackets

INTRODUCTION AND AIM

This study aimed to evaluate the ability of fluoride-releasing adhesives to inhibit enamel demineralization surrounding orthodontic brackets.

METHODS

Two groups of 40 sound human premolars were sectioned mesio-distally. The halves were varnished, and orthodontic brackets were bonded with different adhesive materials. An area 1 mm wide surrounding the brackets was left exposed. Each specimen was immersed daily in a pH cycle for 28 days. In the second group, the specimens were exposed daily to a fluoride solution (250 ppm F-) at 37°C. The fluoride release from different groups was measured. Quantitative light-induced fluorescence (QLF) was used to quantify fluorescence loss of enamel surfaces adjacent to the brackets. Results were statistically analyzed using ANOVA at (p<0.05).

RESULTS

Fluoride released from the three fluoride-releasing adhesives was significantly higher (p<0.001) in the group with daily fluoride exposures than in the group without fluoride exposures. Enamel adjacent to brackets bonded with Fuji Ortho LC, Ketac Cem, and Dyract Cem showed significantly less (p<0.001) changes in (ΔQ) value (less demineralization) than enamel bonded with Transbond, the control adhesive material.

CONCLUSIONS

Using fluoride-releasing adhesives significantly reduced the level of demineralization adjacent to orthodontic brackets.

Evaluation of the Prevalence of White Spot Lesions During Fixed Orthodontic Treatment Among Patients Reporting for Correction of Malocclusion: A Prevalence Study

BACKGROUND

Despite recent breakthroughs in caries preventive measures, one of the biggest issues clinicians confront is preventing demineralization while undergoing orthodontic therapy. The buildup of plaques around orthodontic brackets over time causes white spot lesions (WSLs). The goal of the present research was to assess the prevalence of WSLs in patients undergoing orthodontic treatment before starting therapy and at six and 12 months into therapy, adopting the visual examination approach.

MATERIALS AND METHODS

We looked for WSLs on tooth surfaces gingival to an archwire because this is the area most likely to experience enamel demineralization during orthodontic treatment. The visual assessment was conducted using the following scale at baseline, six months, and 12 months for orthodontic patients: score 0: no demineralization or noticeable white patches on the surface; score 1: mild demineralization with a visible white spot but no surface disruption; score 2: moderate demineralization with a noticeable WSL that has a roughened surface but does not need repair; and score 3: severe demineralization with a noticeable WSL that needs repair. Fisher's exact test was used after a chi-square analysis to determine whether there were any differences between all three categories (six months, 12 months, and control).

RESULTS

The frequency of WSL in patients at 12 months of orthodontic treatment was 46.57%, while it was 11.86% in patients who just started orthodontic treatment. The difference was statistically significant (p = 0.01), showing that the frequency was greater in patients at 12 months of orthodontic treatment as compared to patients who had just started undergoing orthodontic treatment. The frequency of WSL in patients at six months of orthodontic treatment was 37.34%, while it was 11.86% in patients who just started orthodontic treatment. The difference was statistically significant (p = 0.03), showing that the frequency was greater in patients at six months of orthodontic treatment as compared to patients who had just started undergoing orthodontic treatment. The frequency of WSL in patients at six months of orthodontic treatment was 37.34%, while it was 46.57% in patients at 12 months of orthodontic treatment. The frequency was greater in patients at 12 months of orthodontic treatment as compared to patients at six months of orthodontic treatment; however, the difference was non-significant statistically (p = 0.76).

CONCLUSION

This clinical investigation revealed that the number of WSLs increased significantly during the first six months of treatment and then increased gradually until the final 12 months. During the first few months of treatment, doctors should assess the patients' dental hygiene habits and, if necessary, take further precautions to prevent demineralization.

Bonding durability and remineralizing efficiency of orthodontic adhesive containing titanium tetrafluoride: an invitro study

BACKGROUND

Titanium tetrafluoride has been shown to protect tooth enamel from demineralization. This study investigated the effect of incorporating different concentrations of TiF4 (1, 2 and 3 Wt.%) into an orthodontic primer on the shear bond strength of orthodontic brackets and the enamel microhardness after cariogenic challenges.

METHODS

Three different TiF4 concentrations (1, 2 and 3 Wt.%) were prepared and added to the etch and rinse orthodontic primer. Ninety freshly extracted premolars were randomly divided into five groups according to the experimental primers and ageing conditions: TF0, TF0C, TF1C, TF2C, and TF3C. The TF0C group had no TiF4 in the primer, while TF1C, TF2C, and TF3C had 1, 2 and 3 Wt.% TiF4 in the primer, respectively. In the TF0 group, specimens were immersed in deionized water for 24 h as a control group, while all other groups were immersed in a demineralizing solution for 28 days. Each of the five groups was divided into two subgroups: The first group was subjected to shear bond strength and adhesive remnant index testing (N = 50 teeth, 10/group), while the second group was subjected to enamel surface microhardness testing (N = 25 teeth, 50 tooth halves, 10 tooth halves/group). Fifteen teeth (N = 15 teeth, n = 3/group) representing the five groups were subjected to SEM and microelemental analysis (EDX). SBS, ARI, microhardness, and Ca/P ratio were measured, and the data were analyzed using ANOVA and Tukey's tests.

RESULTS

The TF2C group had the highest SBS value (9.93 ± 1.23), while the TF0C (5.24 ± 0.65) and TF3C (5.13 ± 0.55) had the lowest SBS values. The enamel microhardness in the TF0C group was significantly reduced (p < .001). Enamel microhardness values were significantly (p < .001) higher in groups TF1C, TF2C, and TF3C than in TF0C. The highest Ca/P ratio was significantly recorded for the TF2C group (2.65 ± 0.02).

CONCLUSIONS

Incorporation of 1 and 2 Wt.% TiF4 into the orthodontic primers showed adequate bond strength and better remineralization effect. However, 1 Wt.% TiF4 showed lower ARI values than 2 Wt.% TiF4.

Evaluation of the Impact of Chlorhexidine Mouth Rinse on the Bond Strength of Polycarbonate Orthodontic Brackets: A Case-Control Study

BACKGROUND

Shear bond analysis is the procedure used most frequently to gauge the tensile strength of adhesives incorporated in orthodontic treatments. In shear tensile strength analysis, pressure is placed as close as feasible to the interface between the orthodontic bracket and the surface of the tooth, parallel to the long axis of the tooth. Although numerous research on extracted teeth of human and bovine teeth have been conducted, there may still be variables such as pH, humidity, temperature, and others that could affect how these materials behave in the mouth cavity. The impact of chlorhexidine (CHX) on the binding capacity for non-metallic orthodontic brackets in vivo is not well understood.

OBJECTIVE

The goal of the current study is to determine how mouth rinses containing 0.12% CHX affect the adhesive strength of polycarbonate orthodontic brackets.

METHODS AND MATERIALS

Thirty-four patients were part of the test category, and they were instructed to wash their oral cavity for approximately 30 seconds using 20 ml of 0.12% CHX gluconate (Septodent). Thirty-four patients made up the control category and were instructed to wash their oral cavity for 30 seconds with a placebo mouthwash of a similar hue (20 ml). Both types of mouthwash were administered to the participants by an administrator who was not specifically involved in the trial and were kept in 120 ml labeled plastic bottles. The study participants were also kept unaware of the type of mouthwash. For the mouthwash utilized by study participants, a double-blinding technique was applied.

RESULTS

Thirty-four patients were evaluated in the test category. Since the orthodontic bracket broke in two patients, therefore, 32 patients were evaluated in the control category. The mean value of the strength of the shear bond in the experimental category was 15.32 megapascal (Mpa). The SD value was 2.51. The mean value of the strength of the shear bond in the control subgroup was 15.63. On statistical analysis, the t-value was 0.47. The p-value was 0.671. The difference in findings of the strength of the shear bond was statistically non-significant.

CONCLUSION

The results of this investigation allow us to draw the conclusion that the shear bond properties of polycarbonate orthodontic brackets are unaffected when treated with 0.12% CHX preceding the binding. The clinically meaningful adhesion strength was likewise attained by the polycarbonate orthodontic brackets.

In Vitro evaluation of the bond strength of metal brackets adhered to different dental restorative materials using different orthodontic adhesives

Background

During orthodontic treatment, teeth with brackets may sometimes be restored with different restorative materials. In this case, the content of the orthodontic adhesive selected for bracket bonding may also be important.

Aim

This study compared the bond strength of metal orthodontic brackets adhered to different resin composite and glass ionomer cement (GIC) restoration surfaces with glass ionomer-based and resin-based orthodontic adhesives to determine the best orthodontic adhesive for use in restored teeth.

Material and Methods

This study prepared 80 discs. Four material groups of 20 discs were created: reinforced high-viscosity GIC, high-viscosity GIC, flowable bulk-fill resin composite, and nanohybrid resin composite. Specimens in each material group were divided into two subgroups that differed in the orthodontic adhesive used to bond the brackets to the prepared specimens. After 24 hours, the specimens were shear bond strength (SBS) tested at 1 mm/min using a universal tester.

Results

The SBS of glass ionomer-based orthodontic adhesive differed significantly between metal brackets adhered to different bases (P < 0.001). The highest SBSs were observed between metal brackets and high-viscosity glass ionomer restorations (6.79 ± 2.38). The highest SBSs observed with a resin-based orthodontic adhesive were between metal brackets adhered to nanohybrid resin composite restorations (8.84 ± 2.10; P = 0.030).

Conclusions

Glass ionomer-based orthodontic adhesive provided safer bond strength and demineralization prevention when applying metal brackets to teeth with glass ionomer restorations.

Effect of self-assembling peptide and other remineralizing agents on preventing initial enamel lesions around orthodontic brackets: An in vitro comparative study

OBJECTIVE

To investigate and compare the effect of self-assembling peptide SAP (P_11-4), casein phosphopeptide-amorphous calcium phosphate fluoride paste (CPP-ACPF), and fluoride varnish (FV) on preventing enamel demineralization around orthodontic brackets.

MATERIAL AND METHODS

Orthodontic brackets were bonded to the buccal surfaces of 80 freshly extracted human maxillary premolars. Teeth were randomly assigned to four groups (n=20) according to the remineralizing agent used as follows: SAP (P_11-4) group (Curodont™ Protect/Credentis), CPP-ACPF group (MI Paste Plus®/Recaldent™), fluoride varnish group (Profluoride varnish®/VOCO), and control group. All products were applied according to the manufacturer's instructions. Specimens were cycled in daily refreshed demineralizing and remineralizing solutions for 8h and 16h, respectively, for 28 days. The calcium/phosphorus ratio (Ca/P) and surface microhardness (SMH) were evaluated at baseline and at two and four weeks. Two-way ANOVA (analysis of variance), one-way ANOVA and repeated measures ANOVA were used for statistical analysis.

RESULTS

Two-way ANOVA demonstrated significant differences between remineralizing agents and time points. After 4 weeks, the SAP (P_11-4) group had had significantly higher Ca/P ratio and SMH (1.68±0.11 and 346.47±55.38) compared to other groups, followed by CPP-ACPF (1.52±0.19 and 283.53±64.75), FV (1.37±0.14 and 262.80±82.98), and the control group (1.31±0.10 and 213.00±41.95). Significantly higher Ca/P ratio and SMH were observed at 2 weeks in the control group (1.44±0.10 and 269.63±57.37) and FV group (1.52±0.09 and 321.17±55.24) compared to 4 weeks. No significant differences were found regarding Ca/P ratio and SMH at 2 weeks in the CPP-ACPF (1.55±0.15 and 295.14±53.88) and SAP P_11-4 groups (1.64±0.10 and 320.18±58.04) compared to 4 weeks.

CONCLUSION

SAP (P_11-4) had the greatest remineralizing efficacy compared to FV and CPP-ACPF. Moreover, extended period of time improved the preventive efficacy of SAP (P_11-4) compared to the other regimens.

Study on the role of nano antibacterial materials in orthodontics (a review)

Nanoparticles (NPs) are insoluble particles with a diameter of fewer than 100 nanometers. Two main methods have been utilized in orthodontic therapy to avoid microbial adherence or enamel demineralization. Certain NPs are included in orthodontic adhesives or acrylic resins (fluorohydroxyapatite, fluorapatite, hydroxyapatite, SiO2, TiO2, silver, nanofillers), and NPs (i.e., a thin layer of nitrogen-doped TiO2 on the bracket surfaces) are coated on the surfaces of orthodontic equipment. Although using NPs in orthodontics may open up modern facilities, prior research looked at antibacterial or physical characteristics for a limited period of time, ranging from one day to several weeks, and the limits of in vitro studies must be understood. The long-term effectiveness of nanotechnology-based orthodontic materials has not yet been conclusively confirmed and needs further study, as well as potential safety concerns (toxic effects) associated with NP size.

Evaluation of white spot lesions around orthodontic brackets using different bonding agents – An in vivo study

Objectives:

The objectives of the study were to assess the white spot lesions around orthodontic bracket macroscopically using two different bonding agents – one with amorphous calcium phosphate (ACP) (Aegis Ortho) and one without ACP (Transbond XT).

Materials and Methods:

The study comprises 10 patients from 14 to 23 years of age. Patients were divided into control and study groups. Forty premolar teeth were then observed (20 teeth in each group). Bonding procedure was done and brackets were positioned on all four 1st pre-molars teeth and pre-treatment photographs were taken. The experimental material used was Aegis Ortho composite (study group) and Transbond XT (control group). Debonding procedure (by Wing deformation technique) was performed after 16 weeks which led to adhesive fracture at composite resin adhesive bracket interface leaving essentially all adhesive on the enamel. Then, follow-up photographs were taken to evaluate each.

Results:

Aegis Ortho containing ACP used for bonding purpose, provided lesser enamel demineralization than Transbond XT.

Conclusion:

Aegis Ortho for orthodontic bonding is significantly more beneficial and reliable, however, further investigations are also required to understand its clinical performance better.

Effect of nano-zinc oxide and nano-chitosan particles on the shear bond strength of dental composites used as orthodontic adhesive

BACKGROUND

This study aimed to evaluate the effect of the combination of zinc oxide nanoparticles (NPs) and chitosan NPs on the shear bond strength (SBS) of composites used for orthodontic bonding.

METHODS

Four groups of composites (n = 10), containing 0%, 1%, 5%, and 10% w/w NP fillers, respectively, were used to bond brackets to the surfaces of 40 intact bovine incisors. After 1000 rounds of thermal cycling at 5°C-55°C, all specimens were mounted in acrylic blocks. The SBS was tested using a universal testing machine, and the adhesive remnant index scores were registered using a stereomicroscope. Data were statistically analyzed using a 1-way ANOVA and the Kruskal-Wallis test.

RESULTS

The highest value of mean SBS was found in the control group, and the lowest value was found in the group with composite containing 10% NPs. The adhesive remnant index did not differ significantly among the groups (P = 0.823).

CONCLUSIONS

Incorporation of 1% and 5% zinc oxide and chitosan NPs had no effect on the SBS of composite, and the obtained SBS values were similar to that of the control group.

Demineralization prevention with a new antibacterial restorative composite containing QASi nanoparticles: an in situ study

OBJECTIVES

To investigate whether a newly developed dental composite with quaternary ammonium silica dioxide (QASi) nanoparticles incorporated with other fillers into the restorative material demonstrates antibacterial activity by reducing enamel demineralization in an in situ gap model.

MATERIALS AND METHODS

Twenty subjects wearing a lower removable partial denture (RPD) with acrylic flanges on both sides of the mouth were recruited into the 4-week in situ study. The gap model consisted of an enamel slab placed next to a composite, separated by a 38-μm space. In the split-mouth design on one side of the RPD, the composite was the Nobio Infinix composite (Nobio Ltd., Kadima, Israel), and the contralateral side used a control composite. Each participant received enamel slabs from one tooth. The gap model was recessed into the RPD buccal flange, allowing microbial plaque to accumulate within the gap. After 4 weeks of continuous wearing, decalcification (∆Z mineral loss) of the enamel slabs adjacent to the gap was determined by cross-sectional microhardness testing in the laboratory.

RESULTS

The ∆Z for the antibacterial composite test side was 235±354 (mean±standard deviation [SD]; data reported from 17 participants) and statistically significantly lower compared to ∆Z of the control side (774±556; mean±SD) (paired t-test, P<0.0001; mean of test minus control -539 (SD=392), 95% confidence interval of difference: -741, -338).

CONCLUSIONS

This in situ clinical study showed that composites with QASi antibacterial particles significantly reduced demineralization in enamel adjacent to a 38-μm gap over a 4-week period in comparison to a conventional composite.

CLINICAL RELEVANCE

Composites with QASi nanoparticle technology have the potential to reduce the occurrence of secondary caries.

TRIAL REGISTRATION

ClinicalTrials.gov #NCT04059250.

Evaluation of the preventive effect of two concentrations of xylitol varnish versus fluoride varnish on enamel demineralization around orthodontic brackets: a randomized controlled trial

BACKGROUND

The highly prevalent white spot lesions around orthodontic brackets necessitate introducing preventive materials without relying on patient compliance.

OBJECTIVE

To evaluate the antidemineralizing effect of two concentrations of xylitol varnish.

TRIAL DESIGN

Triple-blind, four-arm, parallel-group, single-center, randomized controlled clinical trial.

METHODS

A total of 120 orthodontic patients were randomly assigned to four groups (n = 30), using a computer-generated randomized block list. The treatment groups were: 10% xylitol, 20% xylitol, 5% fluoride, and placebo. Tooth demineralization was measured with DIAGNOdent at T1 (before treatment), followed by varnish application. At T2 (third month), the varnish was re-applied, and at the third (T2) and sixth (T3) months, and after treatment (T4), the demineralization was measured. The white spot lesion frequency was assessed visually after treatment. The participants, the clinician, and data assessors were all blinded to group assignments.

RESULTS

A total of 115 patients underwent per-protocol analyses. At T2, the mean DIAGNOdent numbers in the fluoride and 10% xylitol groups were significantly lower than the placebo group (P = 0.00), with a mean difference of 0.63 (95% CI, 0.15-1.10) and 0.5 (95% CI, 0.04-0.95), respectively. At T3, the fluoride and 10% xylitol groups had significantly lower mineral loss than the placebo group (P=0.046) with a mean difference of 0.52 (95% CI, 0.14-0.89) in the fluoride and 0.45 (95% CI, 0.03-0.86) in the 10% xylitol groups, respectively. However, at T4, only the mean for the 10% xylitol group was significantly different (P=0.049) from the placebo group, with a mean difference of 1.18 (95% CI, 0.42-1.93). Visual assessment showed that after treatment, the prevalence of white spot lesions in the fluoride (P=0.03) and 10% xylitol (P=0.00) groups was less than the placebo group with the odds ratio of 0.67 (95% CI, 0.46-0.96) and 0.43 (95% CI, 0.28-0.64), respectively.

CONCLUSION

The 10% xylitol varnish short-term effects on caries control were significantly greater than 20% xylitol varnish and placebo but similar to fluoride varnish. However, the 10% xylitol long-term effect was almost better than fluoride varnish.

TRIAL REGISTRATION

The protocol was registered at IRCT.ir under the code IRCT20180913041032N1.

Arrest of root caries with an adjuvant chlorhexidine-fluoride varnish over a 12-months observation period: a QLF-analyzed, placebo-controlled, randomized, clinical trial (RCT)

This study aimed at evaluating the effectiveness of an adjuvant chlorhexidine–fluoride varnish (Cervitec F) for prevention and arrest of root caries on elderly participants using quantitative light-induced fluorescence (QLF). 23 participants with two or three non-cavitated root carious lesions were included and assigned to three groups of different varnishes (CF: Cervitec F, P: placebo, DP: Duraphate). Agents were applied once to root surface at baseline and in follow-up after 3, 6 and 9 months. The lesions were assessed clinically and with QLF. QLF-images were analyzed regarding fluorescence loss (ΔF), lesion volume (ΔQ) and bacterial activity (ΔR) before (t₀), after 14 days (t₁), 6- (t₂) and 12-months (t₃). CF showed a significant difference between t₀ and t₃: ∆F (− 12.51 [15.41] vs. − 7.80 [16.72], p = 0.012), ∆Q (− 2339.97 (20,898.30) vs. − 751.82 (5725.35), p < 0.001), ∆R (23.80 [41.70] vs. 7.07 [37.50], p = 0.006). Independently of the varnish application, preventive care seems positively influence the root caries progress. Although within CF group the strongest effect was observed, no superiority of a specific varnish application was confirmed over a 12-months QLF observation period. Extra topical fluoride can help remineralise dentin lesions and QLF can be used as a measurement method to determine changes in the dentin lesions.

Effect of fluoride-releasing 4-META/MMA-TBB resin on enamel demineralization around orthodontic brackets: An in vitro µCT analysis

This study aimed to evaluate the impact of fluoride-releasing 4-META/MMA-TBB resin on the degree of enamel demineralization typically detected around orthodontic brackets using μCT. Enamel-dentin blocks were prepared from bovine teeth. Brackets were attached with either 4-META/MMA-TBB resin (SBC), fluoride-releasing 4-META/MMA-TBB resin (SBF), or fluoride-releasing RMGIC (FLC). The specimens were subjected to demineralization (pH 4.5, 21 days) and scanned by μCT (0, 7, and 21 days). Fluoride ion release under the experimental conditions was measured. The degree of demineralization detected in SBF and FLC was significantly lower than that in SBC; there were no significant differences in the degree of demineralization detected in SBF and FLC. The level of fluoride ion detected in FLC was significantly higher than that detected in SBC. Fluoride-releasing 4-META/MMA-TBB resin protected against enamel demineralization around orthodontic brackets when compared to the results from the fluoride-free resin.

Buffering capacity and antibacterial properties among bioactive glass-containing orthodontic adhesives

This study was to evaluate the acid-buffering capacity and antibacterial properties of orthodontic adhesives containing bioactive glasses (BAGs) (45S5, 45S5F, S53P4), Hydroxyapatite, beta-tricalcium phosphate, and Canasite. Fillers comprising 15 wt% bioactive glasses, HAp, β-TCP, and Canasite incorporated with 55 wt% silanated glass were added to a mixture of UDMA/TEGDMA. Acid-buffering capacity was tested by exposing disc-shaped samples of each adhesive to medium of bacteria-produced acids, and pH changes were recorded at 24 and 48 h. Antibacterial properties were assessed by indirect testing by exposing polymerized adhesive samples to a medium and direct testing by immersing the specimens in solutions containing S. mutans and S. sanguinis. A significant buffering capacity was shown by the 45S5, 45S5F and S53P4 BAG adhesives. The antibacterial properties were not significant in all experimental adhesives. Therefore, the experimental orthodontic adhesives containing BAGs demonstrated a significant buffering capacity but did not show significant antibacterial properties against S. mutans and S. sanguinis.

Comparative in vitro study of the cleaning efficacy of AirFloss ultra and I-Prox Sulcus brushes in an orthodontic phantom model

Preventing biofilm-related risks such as gingivitis and white spot lesions during orthodontic treatments is very challenging. The cleaning efficiencies of AirFloss Ultra and I-Prox P sulcus brushes were evaluated using an orthodontic phantom model. After attaching brackets onto black-coated maxillary KaVo teeth, a plaque substitute was applied. The evaluated tooth surfaces were divided into two areas. Cleaning was performed with an AirFloss Ultra with two (A-2) or four (A-4) sprays or an I-Prox P for two (I-2) or four (I-4) seconds. Images before and after cleaning were digitally subtracted, and the percentage of fully cleaned surfaces was determined (Adobe Photoshop CS5, ImageJ). Statistical analysis was performed by ANOVA and post hoc tests with Bonferroni correction (SPSS 25, p < 0.05). The mean values of total cleaning efficacy were 26.87% for I-2, 43.73% for I-4, 34.93%, for A-2 and 56.78% for A-4. The efficacy was significantly higher for A-4 than for A-2, I-4, and I-2. There were significant differences between the four groups. Repeated cleaning led to an improved result. Within the study limitations, the AirFloss Ultra with four sprays proved to be more efficient than the sulcus brush I-Prox P for cleaning.

Fissure caries inhibition with a CO2 9.3-μm short-pulsed laser-a randomized, single-blind, split-mouth controlled, 1-year clinical trial

OBJECTIVES

The objective of this randomized, single-blind, split-mouth controlled, clinical trial was to evaluate whether the use of a short-pulsed 9.3-μm CO₂ laser increases the caries resistance of occlusal pit and fissures in addition to fluoride therapy over 12 months.

MATERIALS AND METHODS

A total of 60 participants, average age 13.1 years, were enrolled. At baseline, second molars were randomized into test and control, and assessed by ICDAS, SOPROLIFE, and DIAGNOdent. An independent investigator irradiated test molars with a CO₂ laser (wavelength 9.3 μm, pulse duration 4 μs, pulse repetition rate 43 Hz, beam diameter 250 μm, average fluence 3.9 J/cm², 20 laser pulses per spot). Test molars received laser and fluoride treatment, control teeth fluoride alone. Fluoride varnish was applied at baseline and at 6 months. After 6 and 12 months, teeth were again assessed.

RESULTS

A total of 57 participants completed the 6-month and 51 the 12-month recall. Laser-treated surfaces showed very slight ICDAS improvements over time with ICDAS change - 1 in 11% and 8%, no changes (ICDAS change 0) in 68% and 67%, and slightly worsened (ICDAS change 1) in 19% and 24% at 6- and 12-month recalls, respectively, and worsened by two scores in 2% at both recall time points. Control teeth showed significantly higher ICDAS increases, with 47% and 25% showing ICDAS change 0, ICDAS change 1 in 49% and 55%, and ICDAS change 2 in 4% and 20% at 6- and 12-month recalls, respectively. Differences in ICDAS changes between the groups were statistically significant (P = 0.0002 and P < 0.0001; Wilcoxon's signed-rank test, exact). A total of 22% of the participants developed ICDAS 3 scores on the control teeth.

CONCLUSIONS

Microsecond short-pulsed 9.3-μm CO₂ laser irradiation markedly inhibits caries progression in pits and fissures in comparison with fluoride varnish alone.

CLINICAL RELEVANCE

The 9.3-μm CO₂ laser irradiation of pits and fissures enhances caries resistance.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02357979.

Effect of Light-Curable Fluoride Varnish and Conventional Topical Fluoride Varnish on Prevention of Enamel Demineralization Adjacent to Orthodontic Brackets: A Comparative Study

Objectives: Various fluoride varnishes have shown promising result in preventing enamel demineralization around orthodontic brackets as they do not depend on patient compliance. The objective of the study was to compare the effect of light-curable fluoride varnish (Clinpro XT) and conventional topical fluoride varnish (Fluoritop SR) in preventing enamel demineralization adjacent to orthodontic brackets.

Methods: 20 patients who required extraction of four first premolars for orthodontic treatment were bonded with orthodontic brackets and each premolar received single application of Clinpro XT and Fluoritop SR fluoride varnish in 2 diagonally opposite quadrants and rest 2 premolars acted as control. The sample teeth were debonded and extracted after 1 month and 2 months of varnish application. The samples were sectioned using hard tissue microtome and evaluated under polarized light microscopy to measure the depth of demineralization.

Results: Kolmogorov Smirnov test showed normal distribution of data. Comparison between the study groups with depth of demineralization scores showed statistically significant variation in one-way analysis of variance test. Turkey’s multiple post hoc procedures showed statistically significant difference in the depth of demineralization between all the 3 groups after 1 month and 2 months. Dependent t test showed statistically significant increment in the depth of demineralization in all the 3 groups between 1 month and 2 months.

Conclusion: This study concluded that single application of both Fluoritop SR and Clinpro XT was effective in reducing significant depth of demineralization compared to control. Clinpro XT showed significantly less demineralization compared to Fluoritop SR after 1 month and 2 months of varnish application.

In vitro CO2 9.3-μm short-pulsed laser caries prevention-effects of a newly developed laser irradiation pattern

Caries prevention with different lasers has been investigated in laboratory studies and clinical pilot trials. Objective of this in vitro study was to assess whether 9.3-μm microsecond short-pulsed CO₂ laser irradiation enhances enamel caries resistance without melting, with and without additional fluoride application. Seven groups of enamel, totaling 105 human enamel samples, were irradiated with 2 different carbon dioxide lasers with 2 different energy application systems (original versus spread beam; 9.3 μm wavelength, pulse repetition rate 43 Hz vs 100 Hz, fluence ranges from 1.4 to 3.9 J/cm², pulse duration 3 μs to 18 μs). The laboratory pH-cycling was performed with or without additional fluoride, followed by cross-sectional microhardness testing. To assess caries inhibition, the mean relative mineral loss delta Z (∆Z) was determined. To evaluate for melting, scanning electron microscopy (SEM) examinations were performed. For the non-laser control groups with additional fluoride use, the relative mineral loss (ΔZ, vol% × μm) ranged between 512 ± 292 and 809 ± 297 (mean ± SD). ΔZ for the laser-irradiated samples with fluoride use ranged between 186 ± 214 and 374 ± 191, averaging a 58% ± 6% mineral loss reduction (ANOVA, P < 0.01 to P < 0.0001). For the non-laser-treated controls without additional fluoride, the mineral loss increased (ΔZ 914 ± 422 to 1224 ± 736). In contrast, the ΔZ for the laser-treated groups without additional fluoride ranged between 463 ± 190 and 594 ± 272 (P < 0.01 to P < 0.001) indicative of 50% ± 2% average reduction in mineral loss. Enhanced caries resistance was achieved by all applied fluences. Using the spread beam resulted in enhanced resistance without enamel melting as seen by SEM. CO₂ 9.3-μm short-pulsed laser irradiation with both laser beam configurations resulted in highly significant reduction in enamel mineral loss. Modifying the beam to a more homogenous profile will allow enamel caries resistance even without apparent enamel melting.

Decalcification and bond failure rate in resin modified glass ionomer cement versus conventional composite for orthodontic bonding: A systematic review & meta-analysis

BACKGROUND

Demineralized white spot lesions (DWSLs) are one of the unfavourable effects of orthodontic treatment. Resin modified glass ionomer cement (RMGIC) was introduced to reduce its occurrence.

OBJECTIVE

The study aimed to determine the incidence of DWSLs as primary objective and bond failure rate in brackets bonded with RMGIC versus conventional composite (CC) as secondary objective.

MATERIAL AND METHODS

A thorough literature search was done until April 2019 on various databases including Scopus, Web of Science, PubMed, Cochrane database, CINHAL, Dental and Oral Science, and manual search. Only human clinical trials and published in English language were included. We considered the experimental group of orthodontic patients with brackets bonded with RMGIC and the control group with brackets bonded with CC. Blind and induplicate study selection, data extraction, and risk of bias assessment were undertaken. RevMan software was used for data analysis. Odds ratio with 95% confidence intervals (CIs) was used to express the effect estimate of frequency of bracket failure bonded using RMGIC and CC. The risk of bias was assessed using Cochrane risk of bias tool for RCTs and ROBINS-I tool for N-RCTs. Sensitivity analyses and subgroup analysis were performed as well.

RESULTS

Out of 2285 articles, nine met the inclusion criteria. Five were RCTs and four were N-RCTs. Out of nine, seven studies were included in the meta-analysis. A random effect model was used. No significant difference was found in the bond failure rate (risk ratio: 1.48; 95% CI: 0.57-3.87; P≤0.42). No difference was found in the occurrence of DWSLs between the two groups.

CONCLUSIONS

Due to the limited number of studies and studies with high risk of bias, no strong conclusion can be drawn. More studies need to be done to reasonably conclude that RMGIC is beneficial in reducing the occurrence of DWSLs and have comparable bond failure rate. The protocol was registered on PROSPERO (CRD42019125386) prior to the commencement of the systematic review.

Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment

BACKGROUND

Early dental decay or demineralised lesions (DLs, also known as white spot lesions) can appear on teeth during fixed orthodontic (brace) treatment. Fluoride reduces decay in susceptible individuals, including orthodontic patients. This review compared various forms of topical fluoride to prevent the development of DLs during orthodontic treatment. This is the second update of the Cochrane Review first published in 2004 and previously updated in 2013.

OBJECTIVES

The primary objective was to evaluate whether topical fluoride reduces the proportion of orthodontic patients with new DLs after fixed appliances. The secondary objectives were to examine the effectiveness of different modes of topical fluoride delivery in reducing the proportions of orthodontic patients with new DLs, as well as the severity of lesions, in terms of number, size and colour. Participant-assessed outcomes, such as perception of DLs, and oral health-related quality of life data were to be included, as would reports of adverse effects.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 1 February 2019), the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 1) in the Cochrane Library (searched 1 February 2019), MEDLINE Ovid (1946 to 1 February 2019), and Embase Ovid (1980 to 1 February 2019). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Parallel-group, randomised controlled trials comparing the use of a fluoride-containing product versus a placebo, no treatment or a different type of fluoride treatment, in which the outcome of enamel demineralisation was assessed at the start and at the end of orthodontic treatment.

DATA COLLECTION AND ANALYSIS

At least two review authors independently, in duplicate, conducted risk of bias assessments and extracted data. Authors of trials were contacted to obtain missing data or to ask for clarification of aspects of trial methodology. Cochrane's statistical guidelines were followed.

MAIN RESULTS

This update includes 10 studies and contains data from nine studies, comparing eight interventions, involving 1798 randomised participants (1580 analysed). One report contained insufficient information and the authors have been contacted. We assessed two studies as at low risk of bias, six at unclear risk of bias, and two at high risk of bias. Two placebo (non-fluoride) controlled studies, at low risk of bias, investigated the professional application of varnish (7700 or 10,000 parts per million (ppm) fluoride (F)), every six weeks and found insufficient evidence of a difference regarding its effectiveness in preventing new DLs (risk ratio (RR) 0.52, 95% confidence interval (CI) 0.14 to 1.93; 405 participants; low-certainty evidence). One placebo (non-fluoride) controlled study, at unclear risk of bias, provides a low level of certainty that fluoride foam (12,300 ppm F), professionally applied every two months, may reduce the incidence of new DLs (12% versus 49%) after fixed orthodontic treatment (RR 0.26, 95% CI 0.11 to 0.57; 95 participants). One study, at unclear risk of bias, also provides a low level of certainty that use of a high-concentration fluoride toothpaste (5000 ppm F) by patients may reduce the incidence of new DLs (18% versus 27%) compared with a conventional fluoride toothpaste (1450 ppm F) (RR 0.68, 95% CI 0.46 to 1.00; 380 participants). There was no evidence for a difference in the proportions of orthodontic patients with new DLs on the teeth after treatment with fixed orthodontic appliances for the following comparisons: - an amine fluoride and stannous fluoride toothpaste/mouthrinse combination versus a sodium fluoride toothpaste/mouthrinse, - an amine fluoride gel versus a non-fluoride placebo applied by participants at home once a week and by professional application every three months, - resin-modified glass ionomer cement versus light-cured composite resin for bonding orthodontic brackets, - a 250 ppm F mouthrinse versus 0 ppm F placebo mouthrinse, - the use of an intraoral fluoride-releasing glass bead device attached to the brace versus a daily fluoride mouthrinse. The last two comparisons involved studies that were assessed at high risk of bias, because a substantial number of participants were lost to follow-up. Unfortunately, although the internal validity and hence the quality of the studies has improved since the first version of the review, they have compared different interventions; therefore, the findings are only considered to provide low level of certainty, because none has been replicated by follow-up studies, in different settings, to confirm external validity. A patient-reported outcome, such as concern about the aesthetics of any DLs, was still not included as an outcome in any study. Reports of adverse effects from topical fluoride applications were rare and unlikely to be significant. One study involving fluoride-containing glass beads reported numerous breakages.

AUTHORS' CONCLUSIONS

This review found a low level of certainty that 12,300 ppm F foam applied by a professional every 6 to 8 weeks throughout fixed orthodontic treatment, might be effective in reducing the proportion of orthodontic patients with new DLs. In addition, there is a low level of certainty that the patient use of a high fluoride toothpaste (5000 ppm F) throughout orthodontic treatment, might be more effective than a conventional fluoride toothpaste. These two comparisons were based on single studies. There was insufficient evidence of a difference regarding the professional application of fluoride varnish (7700 or 10,000 ppm F). Further adequately powered, randomised controlled trials are required to increase the certainty of these findings and to determine the best means of preventing DLs in patients undergoing fixed orthodontic treatment. The most accurate means of assessing adherence with the use of fluoride products by patients and any possible adverse effects also need to be considered. Future studies should follow up participants beyond the end of orthodontic treatment to determine the effect of DLs on patient satisfaction with treatment.

Effectiveness of caries-preventing agents on initial carious lesions within the scope of orthodontic therapy

Objective

To evaluate the effectiveness of three different caries-preventing agents on artificial caries in a Streptococcus mutans-based caries model.

Methods

Sixty-five caries-free human molar enamel blocks were treated with a demineralization solution and a remineralization solution. The specimens were assigned to the following groups according to the caries-protective product applied: group A, chlorhexidine varnish; group B, fluoride-releasing chemically cured sealant; group C, fluoride-releasing lightcured sealant; group D, positive control (specimens that were subjected to de- and remineralization cycles without treatment with any caries-protective agents); and group E, negative control (specimens that were not subjected to de- and remineralization cycles). Samples in groups A–D were stored in demineralization solution with S. mutans and thereafter in artificial saliva. This procedure was performed for 30 days. Average fluorescence loss (ΔF) and surface size of the lesions were measured using quantitative light-induced fluorescence at baseline and on the 7th, 14th, and 30th days.

Results

After 30 days, group A demonstrated a significant increase in ΔF and the surface size of the lesions, no significant difference in comparison with the positive control group, and a significant difference in comparison with the negative control group. Group B showed no significant changes in both parameters at any of the measurement points. While group C showed increased ΔF after 14 days, no significant fluorescence change was observed after 30 days.

Conclusions

Both fluoride-releasing sealants (chemically or light-cured) show anti-cariogenic effects, but the use of chlorhexidine varnish for the purpose of caries protection needs to be reconsidered.

Benzalkonium chloride in an orthodontic adhesive: Its effect on rat enamel demineralization using color-based image analysis

INTRODUCTION

The aim of this study was to determine the effect of an orthodontic bonding adhesive containing benzalkonium chloride (BAC) on enamel demineralization.

METHODS

Eighteen female Sprague-Dawley rats, aged 8 to 10 weeks, were inoculated with Streptococcus sobrinus for 5 days. The animals were randomly divided into the control, non-BAC, and BAC groups. The 6 animals in each group did not receive any brackets, received brackets on the maxillary left first molars bonded with conventional adhesive, or received brackets on the maxillary left and right first molars bonded with adhesive incorporated with 0.25% and 0.75% BAC (wt/wt), respectively. After 7 weeks, the maxillae were soaked in murexide stain to observe the surface area (mm²) and percentages of enamel demineralization on the palatal, mesial, buccal, and occlusal surfaces of the maxillary molars using color-based image analysis.

RESULTS

The non-BAC and BAC groups exhibited greater enamel demineralization compared with the control group. The surface areas and percentages of enamel demineralization in the BAC group were less compared with the non-BAC group. Less enamel demineralization was noted in the animals treated with 0.75% BAC compared with those given 0.25% BAC in all areas; however, these differences were not great enough to attain statistical significance at the 0.05 level.

CONCLUSIONS

The addition of BAC to an orthodontic composite has the potential to reduce the amount and percentage of enamel demineralization. In addition to being an antibacterial agent, BAC may also have an anticariogenic effect. Increased sample sizes and testing of more concentrations of BAC are recommended.

Novel rechargeable calcium phosphate nanoparticle-filled dental cement

The objectives were to develop a novel rechargeable cement containing amorphous calcium-phosphate nanoparticles (nanoACP) to suppress tooth decay. Five cements were made with: (1) 60% glass particles (experimental control); (2) 40% glass+20% nanoACP; (3) 30% glass+30% nanoACP; (4) 20% glass+40% nanoACP; (5) 10% glass+50% nanoACP. Groups 1-4 had enamel bond strengths similar to Transbond XT (3M) and Vitremer (3M) (p>0.1). The nanoACP cement had calcium and phosphate ion release which increased with increasing nanoACP fillers. The recharged cement had substantial ion re-release continuously for 14 days after a single recharge. Ion re-release did not decrease with increasing recharge/re-release cycles. Groups 3-5 maintained a safe pH of medium (>5.5); however, control cements had cariogenic pH of medium (<4.5) due to biofilm acid. Therefore, nanoACP cement (1) had good bond strength to enamel, (2) possessed calcium and phosphate ion recharge/re-release capability, and (3) raised biofilm pH to a safe level to inhibit caries.

The effect of diode laser irradiation associated with photoabsorbing agents containing remineralizing materials on microhardness, morphology and chemical structure of early enamel caries

Background

This study investigated the effects of laser irradiation associated with photo-absorbing agents containing sodium fluoride (NaF), MI paste Plus or Remin Pro® on microhardness and surface structure of white spot lesions (WSLs).

Material and Methods

Fifty-six premolars were divided into two halves, then immersed in a demineraling solution to induce WSLs. The samples were divided into 8 groups by treatment (n=12) : (1) control, (2) diode laser (810 nm, 500 mW, 90 s), (3) NaF, (4) MI Paste plus, (5) Remin Pro®, (6) NaF + Laser, (7) MI Paste Plus + Laser, (8) Remin Pro® + Laser. Microhardness was measured before and after remineralization treatments. Two samples from each group were selected for SEM analysis.

Results

Microhardness increased significantly after all treatments with the exception of control, Laser and Remin Pro® groups (p >0.05). ANOVA revealed no significant difference in initial microhardness (P=0.21), whereas a significant difference was noted after treatment (P=0.009). The application of sodium fluoride with or without laser irradiation produced the highest microhardness among the groups (p<0.05). SEM analysis revealed some cracks on lased enamel and non-homogenous coatings of minerals after the use of remineralizing products.

Conclusions

The use of NaF either alone or combined with laser irradiation was the most effecttive strategy for increasing microhardness of WSLs. The application of diode laser through photoabsorbing agents containing sodium fluoride or MI Paste Plus did not produce any additional effects in enhancing remineralization of WSLs, whereas the combined application of diode laser with Remin Pro® was effective.

Key words:CPP-ACP, Enamel caries, fluoride, Hydroxyapatite, Low level laser, Microhardness, Remineralization, casein phosphopeptide amorphous calcium phosphate.

The effect of fluoride varnish in preventing enamel demineralization around and under orthodontic bracket

AIM

The aim of this study was to evaluate in vitro the effectiveness of fluoride Vanish™ in preventing enamel demineralization around and under orthodontic brackets, using a laser fluorescence monitoring device on a group of teeth, using a laser fluorescence monitoring device on a group of extracted teeth with bonded brackets.

METHODS

Orthodontic brackets were bonded to 32 extracted premolars. Buccal surfaces of teeth were divided into two halves: mesial and distal, fluoride Vanish™ (3M Unitek, Monrovia, CA, USA) was applied only on the distal half while the mesial one served as control half. Teeth were subjected to two demineralization cycles in standard demineralization solution. Enamel demineralization was measured on both varnished and non-varnished halves at baseline, after first and second demineralization cycles and under the brackets after debonding using laser fluorescence device Diagnodent pen. Data were analyzed using Friedman test followed by Wilcoxon test. Differences were considered statistically significant at P<0.001.

RESULTS

Statistically significant differences were observed between the varnished and non-varnished halves after the first and second demineralization cycles at P<0.001. No significant difference was found between baseline readings and under the brackets in both halves.

CONCLUSION

Fluoride varnish application is effective in preventing enamel demineralization around orthodontic brackets. Fluoride varnish has insignificant effect on enamel mineral content under orthodontic brackets.

Decalcification prevention around orthodontic brackets bonded to bleached enamel using different topical agents

BACKGROUND

The present study was conducted to evaluate the effect of different topical agents utilized for prevention of enamel decalcification around orthodontic brackets bonded to bleached and non-bleached enamel.

METHODS

Human maxillary premolars (n = 120) were divided into two equal groups. Teeth in group I were left without bleaching while those in group II were bleached with Vivastyle gel. Metal brackets were bonded to all the teeth using light-cured adhesive. Each group was divided into six equal subgroups (A, B, C, D, E, and F). In subgroup A, no material was applied (control). In subgroups B, C, D, E, and F, the following materials were applied respectively: Profluorid varnish, Enamel Pro Varnish, Ortho-Choice Ortho-Coat, GC Tooth Mousse, and GC MI Paste Plus. All teeth were cycled in a demineralization solution/artificial saliva for 15 days. Laser fluorescence was used to measure the level of enamel mineralization. The data were statistically analyzed.

RESULTS

Regarding the non-bleaching subgroups, all studied material revealed significant demineralization reduction in comparison to the control subgroup (P < 0.05). Ortho-Choice Ortho-Coat revealed the highest significant effect while GC Tooth Mousse showed the least effect. In bleached subgroups, Profluorid varnish, Enamel Pro Varnish, and Ortho-Choice Ortho-Coat significantly reduced demineralization (P < 0.05) while either GC MI Paste Plus or GC Tooth Mousse had no significant effects (P > 0.05).

CONCLUSIONS

Ortho-Choice Ortho-Coat, and Profluorid and Enamel Pro varnishes could be utilized successfully to reduce enamel demineralization around brackets bonded to either bleached or non-bleached enamel. GC MI Paste Plus and GC Tooth Mousse were effective only in non-bleached enamel.

SEM Evaluation of Enamel Surface Changes and Enamel Microhardness around Orthodontic Brackets after Application of CO2 Laser, Er,Cr:YSGG Laser and Fluoride Varnish: An In vivo Study

Introduction

One of the most undesirable consequences of orthodontic treatment is occurrence of enamel demineralization around orthodontic brackets. Numerous in vitro studies have reported the prevention of enamel demineralization by surface treatment with lasers and fluoride varnish.

Aim

To evaluate the changes on the enamel surface and microhardness around orthodontic brackets after surface treatment by CO₂ laser, Er, Cr:YSGG laser and fluoride varnish in vivo.

Materials and Methods

A double blind interventional study was carried out on 100 premolars which were equally divided into five groups, out of which one was the control group (Group 0). The intervention groups (Group I to IV) comprised of patients requiring fixed orthodontic treatment with all 4 first premolars extraction. Brackets were bonded on all 80 premolars which were to be extracted. Enamel surface treatment of Groups I, II and III was done by CO₂ laser, Er, Cr:YSGG laser and 5% sodium fluoride varnish respectively and Group IV did not receive any surface treatment. A modified T-loop was ligated to the bracket and after two months, the premolars were extracted. Surface changes were evaluated by Scanning Electron Microscopic (SEM) and microhardness testing. Comparison of mean microhardness between all the groups was assessed using post-hoc test with Bonferroni correction.

Results

Group I showed a melted enamel appearance with fine cracks and fissures while Group II showed a glossy, homogenous enamel surface with well coalesced enamel rods. Group III showed slight areas of erosions and Group IV presented areas of stripped enamel. Significant difference was observed between the mean microhardness (VHN) of Group I, Group II, Group III, Group IV and Group 0 with p<0.001. A significant difference of p<0.001 was observed while comparing Group I vs II,III,IV,0 and Group II vs III,IV,0. However, difference while comparing Group III vs IV was p=0.005 and difference between the mean microhardness of Group 0 vs Group III was non significant.

Conclusion

Surface treatment with Er,Cr:YSGG laser causes a positive alteration of the enamel surface increasing its ability to resist demineralization with optimum microhardness as compared to CO₂ laser and sodium fluoride varnish.

Orthodontic Intervention to Impacted and Transposed Lower Canines

Impacted and transposed teeth cause serious difficulties in tooth eruption and movement as well as esthetic and functional outcomes. Proper treatment planning including good biomechanical control is essential in order to avoid side effects during traction and aligning of the impacted and/or transposed teeth. The purpose of the present study was to present a successfully treated female patient having transposed and impacted lower canines by means of a modified lingual arch and fixed orthodontic appliance. A female patient aged 13 years and 9 months presented to the orthodontic department with a chief compliant of bilateral spacing and missing teeth in mandibular dentition. After leveling and creating sufficient space in the mandibular arch for the canines, a modified lingual arch was cemented to the mandibular first molars. The lingual arch had two hooks extending to the distobuccal areas of the canine spaces. Elastic chains were applied between the hooks on the lingual arch and the ligatures tied to the attachments on the canine crowns. The light forces generated by elastic materials caused impacted canines to erupt and tend towards their own spaces in the dental arch. As a result, impacted and transposed lower canines were properly positioned in their spaces, and the treatment results were stable during the retention period.

Distribution of white spot lesions among orthodontic patients attending teaching institutes in Khartoum

BACKGROUND

Fixed orthodontic appliances render teeth cleaning arduous, thus when orthodontic treatment is associated with inadequate oral hygiene practice, development of white spot lesions (WSLs) imposes a significant risk on the dentition. Salivary reservoir of calcium, magnesium, phosphorous and fluoride counteracts demineralization and encourages remineralization providing protection against caries challenge. The investigation of the factors leading to WSLs' development is mandatory for appropriate prevention strategies planning. The present study aimed at evaluating the prevalence, pattern of distribution and contributing factors to WSLs' development, among orthodontic patients attending orthodontic departments in teaching institutes in Khartoum.

METHODS

This cross-sectional descriptive, analytical clinical based study was carried out among fixed orthodontic patients attending teaching institutes in Khartoum State. All patients visiting the clinics for their follow up during a 3 months period and fulfilling the inclusion criteria were included. The International Caries Detection and Assessment System (ICDAS) served as a guide for standardized visual caries assessment. Saliva samples were collected from a sample of patients and the levels of calcium and phosphorus were measured. Patients were interviewed regarding their oral hygiene habits (frequency of tooth brushing, use of interdental brushes and mouth washes). Frequency distribution tables as well as graphs, Pearson's correlations and Spearman's correlation were used in the statistical analysis.

RESULTS

The overall prevalence of WSLs was 61.4%. The prevalence for each tooth was: 48.1% in the canine, 32.3% in the lateral incisor, 31.6% in both the central incisor and the first premolar, 27.2% in the second premolar and 8.9% in the first molar. No significant relationship between WSLs prevalence, age and gender or oral hygiene measures was found. There was no significant difference in calcium and phosphorus level between participants with WSLs or those with sound teeth (p-values for calcium and phosphorus were 0.154 and 0.567 respectively).

CONCLUSIONS

Within the limitations of this study it was found that WSLs among fixed orthodontic patients represented an issue of concern. High prevalence of WSLs was recorded among orthodontic patients in Sudan, indicating a need for more stringent prevention programmes and oral hygiene practices prior to initiation of orthodontic treatment.

Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

Comparative assessment of fluoride varnish and fluoride film for remineralization of postorthodontic white spot lesions in adolescents and adults over a 6-month period: A single-center, randomized controlled clinical trial

INTRODUCTION

The objective of this 3-arm parallel randomized trial was to evaluate the effects of a fluoride varnish and a fluoride film on the remineralization of white spot lesions around orthodontic brackets after orthodontic treatment.

METHODS

Patients who had recently completed orthodontic treatment were randomly assigned to the varnish, film, and control groups. Eligibility criteria included age of 12 to 25 years, good general health, and at least 1 maxillary anterior tooth with a white spot lesion. The primary outcome was the decrease in the lesion volume of each patient after 6 months of treatment; fluorescence loss and area were the secondary outcome measures. Randomization was accomplished according to a computer-generated randomization schedule, and allocation concealment was achieved with nontransparent concealed envelopes. Blinding was applicable for the treatments only. The test groups received fluoride varnish or film treatment once a month for 6 months, and the control group received a placebo treatment. All patients received oral hygiene education and were required to use fluoride toothpaste daily. Quantitative light-induced fluorescence images were taken at baseline and at the 3-month and 6-month follow-ups. A mixed-effects linear model was used to analyze quantitative light-induced fluorescence parameters with confounders integrated into the model.

RESULT

Two hundred forty patients (mean age, 16.9 years; range, 12-25 years) with 597 teeth with a white spot lesion were randomized 1:1:1 to the varnish, film, and control groups. Baseline demographics were similar between groups, and 29 patients were lost to follow-up. The primary analysis was carried out on a per-protocol basis involving 72 patients in the control group, 69 patients in the varnish group, and 70 patients in the film group who completed the study. The product of fluorescence loss and lesion area values were statistically associated with time (estimate, -4.58; 95% confidence interval [CI], -5.84 to -3.31; P <0.0001), and a significant decrease in the product of fluorescence loss and lesion area was observed in all groups after 6 months with each treatment. The interaction between group and time in the statistical analysis indicated that the product of fluorescence loss and lesion area values of the 3 groups followed different trends over time. Further pair-wise comparisons showed that the decreases in the 2 test groups were significantly greater than those in the control group (varnish vs control: estimate, -11.83; 95% CI, -15.39 to -8.26; P <0.0001; film vs control, estimate: -7.72; 95% CI, -11.34 to 4.10; P <0.0001) in the analysis for 6 months. In addition, the decrease in the varnish group was significantly greater than that in the film group (estimate, 4.11; 95% CI, 0.48 to 7.73; P = 0.0266) in the analysis for 6 months. No serious adverse effects associated with the use of the tested varnish, film, or placebo occurred.

CONCLUSIONS

After removal of the orthodontic brackets, some natural remineralization of white spot lesions occurred, and daily use of fluoride toothpaste may be helpful for this process. However, not all patients experienced this remineralization, and treatment with fluoride varnish or fluoride film induced greater remineralization of white spot lesions. In addition, our results suggest that fluoride varnish may be slightly more effective than fluoride film. However, further similar clinical trials with more patients are needed to definitively determine which fluoride treatment is most effective.

REGISTRATION

This trial was registered on the Chinese Clinical Trial Register, number ChiCTR-TRC-13003764.

PROTOCOL

The details of the trial protocol are posted online at: http://apps.who.int/trialsearch/Trial.aspx?TrialID=ChiCTR-TRC-13003764.