Current treatment modalities of orthodontically induced white spot lesions and their outcome - a literature review

The effect of antimicrobial peptide-added adhesive resins on shear bond strength and the adhesive remnant index of orthodontic brackets

OBJECTIVES

The aim of this study was to evaluate the effect of in-vivo produced Nisin which is an antimicrobial peptide (AMP) added to adhesive resin on shear bond strength (SBS) and the adhesive remnant index (ARI) of orthodontic brackets.

METHODS

Bacterial AMP was produced by fermentation and the ideal AMP/Bond concentration and antimicrobial efficacy of the mixture were tested. To evaluate the SBS and ARI scores of AMP-added adhesive resins, 80 maxillary premolar teeth extracted for orthodontic purposes were used and randomly assigned into 2 groups (n = 40). Group 1: Control Group (teeth bonded with standard adhesive resin); Group 2: Experimental Group (teeth bonded with AMP-added adhesive resin). Statistical analysis was performed using the SPSS package program and applying the Mann-Whitney U and Fisher's exact tests. P < 0.05 was considered as statistically significant.

RESULTS

Nisin synthesized in-vivo from Lactococcus lactis (L. lactis) (ATCC 7962) bacteria was provided to form a homogenous solution at an ideal concentration To find the minimum AMP/Bond mixture ratio that showed maximum antimicrobial activity, AMP and Bond mixtures were tested at various concentration levels between 1/160 and 1/2 (AMP/Bond). As a result, the optimum ratio was determined as 1/40. The antimicrobial efficacy of Nisin-added adhesive resin was tested against Streptococcus mutans (S. mutans) (ATCC 35,688) and Lactobacillus strains (cariogenic microorganisms). AMP formed a 2.7 cm diameter zone alone, while 1/40 AMP-bond mixture formed a 1.2 cm diameter zone. SBS values of the teeth bonded with Nisin added adhesive (17.49 ± 5.31) were significantly higher than the control group (14.54 ± 4.96) (P = 0.004). According to the four point scale, Nisin added adhesive provided a higher ARI score in favour of the adhesive and tooth compared to the control group (ARI = 3, n = 20).

CONCLUSIONS

Nisin produced from L. lactis (ATCC 7962) had greater antimicrobial effects after mixing with adhesive bond against cariogenic microorganisms S. mutans (ATCC 35,688) and Lactobacillus strains. Nisin added adhesive increased shear bond strength (SBS) of orthodontic brackets and ARI scores in favor of adhesive & teeth.

CLINICAL RELEVANCE

Clinicians should take into account that using Nisin-added adhesive resin in orthodontic treatments can provide prophylaxis against tooth decay, especially in patients with poor oral hygiene.

The Effect of Resin Infiltration Technique on the Calculated Color Change of Demineralized Lesions of Different Severities

OBJECTIVE

To assess the color change of demineralized enamel lesions of different severities after resin infiltration using both clinical spectrophotometry and digital photography.

METHODS AND MATERIALS

Sixty sound human premolars were randomly divided into 3 groups according to the demineralization level. All the teeth were immersed in a demineralizing solution of a pH adjusted to 4.4 at 37°C. Three levels of demineralization were obtained (D1 shallow, D2 moderate, D3 deep) according to the demineralization time. The demineralized area was then infiltrated by low-viscosity resin (ICON, DMG, Germany). Two instrumental methods were utilized to assess the color difference, a clinical spectrophotometer and digital photography at three time points (sound, demineralized, and infiltrated enamel) to calculate the color difference between sound and demineralized enamel (ΔE1) and between sound and infiltrated enamel (ΔE2). Statistical analysis was performed by ANOVA, followed by Tukey's post hoc test. The correlation was analyzed using linear regression.

RESULTS

Two-way ANOVA showed statistically significant differences for both levels of the study (p≤0.05). The color change (ΔE1) and (ΔE2) for different demineralization levels showed statistically significant differences between all groups. For both clinical spectrophotometry and digital photography, D3 showed the highest difference followed by D2 and then D1. As for (ΔE1) calculations, digital photography had a significantly higher difference than spectrophotometry for the D1 group (5.47±0.93 vs 2.78±0.58). As for (ΔE2) digital photography had a statistically significantly lower difference than spectrophotometry (5.55±1.05 vs 6.48±0.76) for the D3 group.

CONCLUSIONS

Color correction after resin infiltration is affected by the demineralization level of enamel. Clinical spectrophotometry and digital photography can detect similarly the color change of demineralized enamel after resin infiltration in shallow and moderate demineralization. However, in deep demineralization clinical spectrophotometry tends to exaggerate the color change compared to digital photography.

Sustained antibacterial activity of orthodontic elastomeric ligature ties coated with a novel kombucha-derived bacterial nanocellulose: An in-vitro study

Incipient carious lesions, the most common complication in orthodontic patients with fixed appliances, call for the development of novel preventive dental materials that do not rely on patient adherence. The present study aimed to assess the ability of elastomeric ligatures coated with bacterial nanocellulose (BNC) to deliver sustained antibacterial activity, during the standard 28-day interval between orthodontic appointments, without compromising their mechanical properties. Kombucha membrane was used to produce cellulose as a secondary product from the fermentation of tea broth with symbiotic bacteria and yeast culture. Characterization of BNC-coated elastomeric ligatures was performed using Fourier Transform Infrared Spectroscopy and Energy Dispersive Spectroscopy analysis. The samples were pre-treated by immersion first in isopropyl alcohol, then in 8 mL nanocellulose solution for 7 days. Tensile strain and strength of the BNC-coated and conventional ligatures were evaluated using a tensile testing machine. Direct contact and agar diffusion tests were performed to assess the antibacterial activity of nanocellulose. In addition, the release profile of BNC was evaluated. Data analysis was performed by one-way analysis of variance (ANOVA) followed by post-hoc Tukey's test and Wilcoxon signed-rank test. P values less than 0.05 was regarded as significant. There was no statistically significant difference in tensile strain and strength between the BNC-coated and conventional ligatures. The coated ligatures provided sustained antibacterial activity during the required 28 days. The use of BNC-coated elastomeric ligatures in patients with fixed orthodontic appliances might be a promising solution to plaque formation and subsequent enamel decalcification.

Comparative evaluation of four treatments for postorthodontic white spot lesions: a randomized controlled trial

OBJECTIVES

To evaluate the treatment efficacy of fluoride toothpaste alone and those of adjunctive use of resin infiltration, sodium fluoride varnish, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on white spot lesions (WSLs).

MATERIALS AND METHODS

Seventy-nine patients (356 teeth) with WSLs after orthodontic treatment were randomly allocated into four groups. The WSLs of the participants received resin infiltration only at baseline, and the other groups received fluoride varnish, CPP-ACP mousse, and placebo treatment every 6 months, respectively. A toothpaste containing 1400 ppm fluoride and toothbrushes were distributed to all participants, and oral hygiene instructions were provided. Photos of the teeth with WSL were taken to compare the change between groups which was measured by ImageJ software.

RESULTS

Twelve months later, different degrees of reduction in the area of WSLs were observed in all groups. The percentage of lesion area reduction in WSLs in the resin infiltration group was 46.6%, which was significantly higher than that in fluoride varnish group (26.6%), CPP-ACP group (28.6%), and control group (29.8%), and the differences were statistically significant (p < 0.001).

CONCLUSIONS

This study shows that after 1-year follow-up, the use of fluoride toothpaste, with or without the use of fluoride varnish or CPP-ACP, can reduce the area of WSLs. While resin infiltration can immediately improve dental aesthetics and continuously improved in 12 months, resin infiltration group showed much better results than other groups.

TRIAL REGISTRATION

Clinical Trials Registration Number: ChiCTR2000032516.

CLINICAL SIGNIFICANCE

The use of fluoride toothpaste, with or without adjunctive use of fluoride varnish and CPP-ACP, can reduce the area of WSLs, while resin infiltration treatment has additional effect and can immediately improve dental aesthetics.

Candida albicans enriched in orthodontic derived white spot lesions and shaped focal supragingival bacteriome

White spot lesions (WSLs) are common enamel infectious diseases in fixed orthodontic treatment, which might attribute to the dysbiosis of oral microbiome. However, the correlation of Candida albicans with oral bacteriome in WSLs still remains unrevealed. This study investigated the carriage of C. albicans and how it shaped the bacterial community in disease or healthy supragingival plaque, to explore the potential role of interkingdom interaction in orthodontic WSLs. In this study, 31 patients with WSLs (WSLs) and 23 healthy patients (Health) undergoing fixed orthodontic treatment were enrolled. The supragingival microbiota in both groups were determined using 16S rRNA gene sequencing. Colonization and abundance of C. albicans in the plaque were determined via culture-dependent and -independent methods. Among WSLs patients, the correlation of C. albicans and bacteriome was analyzed under QIIME2-based bioinformatics and Spearman's correlation coefficient. The raw reads were deposited into the NCBI Sequence Read Archive (SRA) database (Accession Number: SRP404186). Significant differences in microbial diversity as well as composition were observed between WSLs and Health groups. Leptotrichia remarkably enriched in the WSLs group, while Neisseria and Cardiobacterium significantly enriched in the Health group. In addition, 45% of WSLs patients were C. albicans carriers but none in patients without WSLs. Among all WSLs patients, beta diversity and microbial composition were distinguished between C. albicans carriers and non-carriers. In C. albicans carriers, Corynebacterium matruchotii and Streptococcus mutans significantly enriched whereas Saccharibacteria_TM7_G-1 significantly depleted. The abundance of C. albicans was positively associated with bacteria such as Streptococcus mutans, while the negative correlation was detected between C. albicans and several bacteria such as Cardiobacterium hominis and Streptococcus sanguinis. Our study elucidated the distinguished supragingival plaque microbiome between orthodontic patients with and without WSLs. C. albicans frequently existed and enriched in orthodontic derived WSLs. The carriage of C. albicans shape plaque bacterial community in demineralized lesions and might play roles in WSLs pathogenesis.

Oral Health Self-Management Ability and Its Influencing Factors among Adolescents with Fixed Orthodontics in China: A Mixed Methods Study

Objective. To understand the oral health self-management ability status and influencing factors among adolescent patients with fixed orthodontics in Nanjing and to provide a reference for formulating targeted intervention measures. Methods. A mixed research method was used. First, the convenience sampling method was used to select adolescent patients with fixed orthodontics admitted to the orthodontic department of a dental hospital in Nanjing from November 2021 to March 2022. The oral health self-management ability questionnaire was used for the investigation; then, 15 children with poor oral health management ability were selected for in-depth interviews. Results. The total score of oral health self-management ability of 290 adolescent children with fixed orthodontics was 45.6-90.8 points, with an average score of $69.63\pm 7.40$ of which knowledge, belief, and behavior dimension scores were $72.09\pm 10.47,68.50\pm 10.13,\text{and}67.63\pm 8.67$ , respectively, and the environmental score was $69.91\pm 12.50$ . Multiple regression analysis showed that sex, age, bracket wearing time, grade, and place of residence were related to the scores of each dimension of self-management. Qualitative research shows that the main reasons for the poor oral health self-management ability of adolescents with fixed orthodontics are the lack of awareness during fixed orthodontics, lack of knowledge channels, low compliance, inability to solve oral problems during treatment, difficulty in adhering to oral care behaviors, and lack of motivation to treat. Conclusion. The oral health self-management ability of adolescent children with fixed orthodontics needs improvement, and a precise health intervention plan should be formulated.

Microinvasive esthetic approach for deep enamel white spot lesion

The white spot lesion on the dental enamel is an optical alteration that compromises the esthetics of smile. It can be caused by many factors, among them, defects in mineralization and formation of tooth enamel. Resin infiltrants are agents that penetrate, by capillarity, through the pores of the demineralized or hypomineralized enamel, altering the refractive index (RI) of the tooth structure and totally or partially masking the appearance of the white spot. The aim of this work was to report the use of resin infiltration to minimize the visualization of white spot lesion, present in an upper central incisor, as a microinvasive approach for the esthetic treatment of deep enamel hypomineralization. A 20-year-old female patient sought care with the esthetic complaint of extensive white spot lesion on the buccal face of her upper right central incisor. The diagnosis established was a deep white stain associated with the incisor molar hypomineralization syndrome, and the treatment of choice for the resolution of the case was the application of the Icon^® resin infiltrant (DMG, Hamburg, Germany). To reach the body of the lesion, three cycles of acid erosion, using 15% HCl, were necessary to obtain a satisfactory aspect of masking the white lesion. A camouflage effect of the deep white spot lesion was achieved with the use of the resin infiltration, without the need of additional and irreversible wear of the dental structure.

White Spots Prevalence and Tooth Brush Habits during Orthodontic Treatment

White spots (WS) are one of the most undesirable side effects in patients undergoing orthodontic therapy and are usually located around bracket bases and even detected under the molar bands. The aim of the present cross-sectional study was to evaluate the WS lesion during orthodontic therapy and the correlation between WS and oral hygiene habits. Patients requiring orthodontic treatment with a fixed appliance were screened for the inclusion/exclusion criteria, and 74 subjects were finally enrolled. Each patient received three examinations: at T0, the day of the application of the fixed appliance; at T1, three months later; and at T2, six months after treatment start. After calculating descriptive statistics, differences between groups were evaluated with an independent sample t-test. The first type error was set as p ≤ 0.01. The observed prevalence of WS lesions was 59.5% on T1 and 60.8% on T2. The most affected teeth result to be upper molars, lower left first molar, upper right central incisor and upper left lateral incisor, upper right canine, upper left first premolar, and lower right first molar. A higher frequency of daily tooth brushing was accompanied by a lower prevalence of WS. No significant effect of sex was observed.

Antibacterial and white spot lesions preventive effect of an orthodontic resin modified with silver-nanoparticles

Background

To evaluate the antibacterial property of a modified orthodontic resin with different concentrations of silver-nanoparticles (AgNPs), and quantify its preventive effect on the formation of white spot lesions (WSLs).

Material and Methods

An orthodontic resin (Transbond XT) was modified with four concentrations of AgNPs (1%, 0.5%, 0.1%, and 0.05%), the orthodontic resin without AgNPs was used as control. Polymerized resin discs (n=80) were submitted to Agar diffusion test on Petri dishes inoculated with Streptococcus mutans and Lactobacillus acidophilus. In addition, resin discs of each group (n=40) were placed in 96-well plates with bacterial suspensions to evaluate the colony-forming-units (CFU). For the WSLs prevention test, brackets were bonded with the experimental orthodontic resins on 45 premolars (n=5), and were subjected to a microbiological caries induction method for 9 days. Photographs were taken before and after the test, and the images were evaluated with the Image J software to calculate the area of WSLs. The data were analyzed using ANOVA and Tukey-HSD test, Student´s t-test and Kruskal-Wallis test (α=0.05).

Results

The 0.5% and 1% AgNPs modified resin inhibit the growth of S. mutans and L. acidophilus. All the modified resins showed significantly less CFU, when compared to the control (p<0.05). 1% AgNPs resin promote the higher prevention of WSLs formation. There was no significant difference between the control group and the 0.1% and 0.05% groups.

Conclusions

0.5% and 1% of AgNPs modified orthodontic resin exhibit an important antibacterial activity against S. mutans and L. acidophilus, and prevent the formation of WSLs.

Key words:White spot lesions, antibacterial, orthodontics, adhesive, Silver-nanoparticles.

Fluoride release from two types of fluoride-containing orthodontic adhesives: Conventional versus resin-modified glass ionomer cements-An in vitro study

INTRODUCTION

Development of white spot lesions (WSLs) during orthodontic treatment is a common risk factor. Fixation of the orthodontic appliances with glass ionomer cements could reduce the prevalence of WSL's due to their fluoride release capacities. The purpose of this study was to evaluate differences of fluoride release properties from resin-modified and conventional glass ionomer cements (GICs).

METHODS

The resin-modified GICs Fuji ORTHO LC (GC Orthodontics), Meron Plus QM (VOCO), as well as the conventional GICs Fuji ORTHO (GC Orthodontics), Meron (VOCO) and Ketac Cem Easymix (3M ESPE) were tested in this study. The different types of GICs were applied to hydroxyapatite discs according to the manufacturer's instructions and stored in a solution of TISAB III (Total Ionic Strength Adjustment Buffer III) and fluoride-free water at 37°C. Fluoride measurements were made after 5 minutes, 2 hours, 24 hours, 14 days, 28 days, 2 months, 3 months and 6 months. One factor analysis of variance (ANOVA) was used for the overall comparison of the cumulative fluoride release (from measurement times of 5 minutes to 6 months) between the different materials with the overall level of significance set to 0.05. Tukey's post hoc test was used for post hoc pairwise comparisons in the cumulative fluoride release between the different materials.

RESULTS

The cumulative fluoride release (mean ± sd) in descending order was: Fuji ORTHO LC (221.7 ± 10.29 ppm), Fuji ORTHO (191.5 ± 15.03 ppm), Meron Plus QM (173.0 ± 5.89 ppm), Meron (161.3 ± 7.84 ppm) and Ketac Cem Easymix (154.6 ± 6.09 ppm) within 6 months. Analysis of variance detected a significant difference in the cumulative fluoride release between at least two of the materials (rounded p-value < 0.001). Pairwise analysis with Tukey's post hoc test showed a significant difference in the cumulative fluoride release for all the comparisons except M and MPQM (p = 0.061) and KCE and M (p = 0.517).

CONCLUSION

Fluoride ions were released cumulatively over the entire test period for all products. When comparing the two products from the same company (Fuji ORTHO LC vs. Fuji ORTHO from GC Orthodontics Europe GmbH and Meron Plus QM vs. Meron from VOCO GmbH, Mannheim, Germany), it can be said that the resin-modified GICs have a higher release than conventional GICs. The highest individual fluoride release of all GICs was at 24 hours. A general statement, whether resin-modified or conventional GICs have a higher release of fluoride cannot be made.

Impact of self-assembling peptides in remineralisation of artificial early enamel lesions adjacent to orthodontic brackets

Enamel demineralisation can occur as a side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the efficacy of the self-assembling peptide P11-4 for remineralisation combined with fluorides, compared to application of fluoride varnish alone. De- and remineralisation was assessed by Quantitative light-induced fluorescence (QLF). Orthodontic brackets were bonded on 108 human enamel samples and white spot lesions were created. The samples were allocated randomly into three groups: Group I received no treatment, group II had a single application of fluoride varnish (22,600 ppm), and group III was treated with P11-4 following a single application of fluoride varnish. Quantitative light-induced fluorescence (QLF) measurements were performed at baseline, after demineralisation and after storage in remineralisation solution for 7 and 30 days. Non-parametric tests (Kruskal-Wallis test and Friedman test) were used for further analysis. After demineralisation, all samples showed a median ΔF -9.38% ± 2.79. After 30 days median ΔF values were as followed: group I = -9.04% ± 2.51, group II = -7.89 ± 2.07, group III = -6.08% ± 2.79). The median ΔF values differed significantly between all groups at all investigation times (p < 0.00001). Application of P11-4 with fluoride varnish was superior to the use of fluorides alone for remineralisation of enamel adjacent to brackets.

Comparison of the effects of toothpastes containing nanohydroxyapatite and fluoride on white spot lesions in orthodontic patients: A randomized clinical trial

BACKGROUND

Studies show that fluoride (F) and nano-hydroxyapatite (nano-HA) would result in remineralization of white spot lesions (WSLs), which are among the most prevalent consequences of fixed orthodontic treatment. The present study evaluates and compares the clinical effects of an Iranian toothpaste containing nano-HA with F-containing one on early enamel lesions.

MATERIALS AND METHODS

In this randomized clinical trial study, 50 patients who had received fixed orthodontic treatment were recruited immediately after debonding. Three photographs, including frontal, lateral right and left views of occlusion, were obtained. Moreover, surfaces with WSLs were recorded using DIAGNOdent. Plaque index of each patient determined using disclosing agents. At first visit, each patient was asked to select one type of toothpaste (nano-HA containing vs. F containing named A or B), randomly and were instructed how to brush their teeth (25 patients in each group). Examination was done at 1, 3, and 6 months' intervals. Finally, photographs were analyzed by Digimizer (V5) software, and the lesion extent was recorded in pixels. SAS 9.4 was used to analyze data and was set at 0.05.

RESULTS

According to data, lesion extent showed a significant decrease (P < 0.001). At baseline, the difference between the two groups regarding the lesion extent was 268 pixels while it dropped to 89 pixels after 6 months. DIAGNOdent results showed that at baseline, fluorescence difference was 0.3 while it reached the number of 0.8 after 6 months, indicating the outperformance of nano-HA containing toothpaste.

CONCLUSION

The Iranian nano-HA containing toothpaste performed better than F-containing one in terms of the amount of remineralization and diminishing the lesion extent.

Effect of the caries-protective self-assembling peptide P11-4 on shear bond strength of metal brackets

Purpose

During orthodontic treatment with fixed appliances, demineralization around brackets often occurs. The aim of this in vitro study was to investigate the effect of the caries-protective self-assembling peptide P11‑4 (SAP P11-4) on the shear bond strength of metal brackets.

Methods

In all, 45 extracted human wisdom teeth were available for the study. The teeth were randomly divided into 3 groups (each n = 15) and pretreated as follows: test group 1: application of SAP P11‑4 (Curodont Repair, Windisch, Switzerland) and storage for 24 h in artificial saliva; test group 2: application of SAP P11‑4; control group: no pretreatment with SAP P11‑4. A conventional metal maxillary incisor bracket (Discovery, Dentaurum, Ispringen) was adhesively bonded to each buccal surface. The shear bond strength was tested according to DIN 13990. After shearing, the Adhesive Remnant Index (ARI) was determined microscopically (10 × magnification). Analysis of variance (ANOVA) was used to check the groups for significant differences (α = 0.05). The distribution of the ARI scores was determined with the χ ² test.

Results

There was no significant difference in shear forces between the groups (p = 0.121): test group 1 = 17.0 ± 4.51 MPa, test group 2 = 14.01 ± 2.51 MPa, control group 15.54 ± 4.34 MPa. The distribution of the ARI scores between the groups did not vary (p-values = 0.052–0.819).

Conclusion

The application of the caries protective SAP P11‑4 before bonding of brackets did not affect the shear bond strength. Therefore, pretreatment of the enamel surface with SAP P11‑4 shortly before bracket insertion can be considered.