White-spot lesions during multibracket appliance treatment: A challenge for clinical excellence

Assessment of biofilm formation on ceramic, metal, and plastic brackets in orthodontic materials by new method using renG-expressing Streptococcus mutans

OBJECTIVE

Oral biofilm has a high acid-producing capacity, increases the risk of enamel demineralization around brackets, and has been identified as a problem in orthodontic treatment. Here, we assessed the risk of biofilm formation by Streptococcus mutans, which is associated with the development of white spot lesions (WSL) on tooth surfaces, using multibracket devices.

METHODS

Various types of brackets were used for the biofilm formation assay with S. mutans coated with human saliva, immersed in renG-expressing S. mutans UA159 (strain with the luciferase gene inserted), and incubated overnight at 37°C under aerobic conditions containing 5% CO2. The biofilm was washed twice with phosphate-buffered saline (PBS), and 200 μL of luciferin dissolved in PBS was added to each well. The mixture was light shielded and allowed to react for 20 min. Luminescence was measured as the amount of biofilm formed by live cells on the bracket surfaces using an optical emission spectrophotometer.

RESULTS

Biofilm formation was greater in plastic brackets than in ceramic and metal brackets in a number-dependent manner. However, biofilm formation was inhibited as the plastic bracket was coated with saliva.

CONCLUSION

For preventive treatments of WSL onset during orthodontic treatment, orthodontists should carefully select and customize brackets based on patient needs, goals, and biomechanical principles. This study developed a new measurement method using renG-expressing S. mutans UA159 to accurately assess active biofilm formation on bracket surfaces.

A comparative evaluation of the antimicrobial efficacy of Chlorhexidine and Chlorine dioxide on self-ligating brackets contaminated with Streptococcus mutans biofilm- An In vitro study

Objective

To evaluate and compare antimicrobial efficacy of Chlorhexidine and Chlorine dioxide mouthwashes on S.mutans biofilm created on metal and ceramic self-ligating brackets.

Materials and methods

A total of 162 metal and ceramic self-ligating brackets (3M™ SmartClip™ & Clarity SL™) were randomly divided into 3 groups and 2 subgroups. Standard procedures were followed to coat all brackets with S.mutans biofilm. The biofilms were cultivated which were then subjected to the effects of the mouthwashes. Quantitative assessment was carried out by comparing the number of viable colonies of S.mutans. A Mann-Whitney U test was used to compare the data between the experimental and control groups. (p < 0.05).

Result

When compared to untreated controls the antimicrobial efficacy of Chlorhexidine Digluconate and Chlorine Dioxide mouthwashes was found to be statistically significant (p = 0.00). The comparison between Chlorhexidine digluconate and Chlorine dioxide mouthwashes was not statistically significant in Ceramic self-ligating group (p = 0.502) and statistically significant in Metal self-ligating group (p = 0.001).

Conclusion

S mutans colonies on metal and ceramic self-ligating brackets can be reduced effectively by Chlorhexidine digluconate and Chlorine dioxide mouthwashes. Chlorhexidine digluconate more effective for metal bracket group. Both mouthwashes had comparable antimicrobial effectiveness, with the difference in the number of viable colonies following exposure for ceramic bracket groups.

Applications of nanotechnology in orthodontics: a comprehensive review of tooth movement, antibacterial properties, friction reduction, and corrosion resistance

Nanotechnology has contributed important innovations to medicine and dentistry, and has also offered various applications to the field of orthodontics. Intraoral appliances must function in a complex environment that includes digestive enzymes, a diverse microbiome, mechanical stress, and fluctuations of pH and temperature. Nanotechnology can improve the performance of orthodontic brackets and archwires by reducing friction, inhibiting bacterial growth and biofilm formation, optimizing tooth remineralization, improving corrosion resistance and biocompatibility of metal substrates, and accelerating or decelerating orthodontic tooth movement through the application of novel nanocoatings, nanoelectromechanical systems, and nanorobots. This comprehensive review systematically explores the orthodontic applications of nanotechnology, particularly its impacts on tooth movement, antibacterial activity, friction reduction, and corrosion resistance. A search across PubMed, the Web of Science Core Collection, and Google Scholar yielded 261 papers, of which 28 met our inclusion criteria. These selected studies highlight the significant benefits of nanotechnology in orthodontic devices. Recent clinical trials demonstrate that advancements brought by nanotechnology may facilitate the future delivery of more effective and comfortable orthodontic care.

Effectiveness of Fluoride Varnishes for White Spot Lesion Prevention and Remineralization during Orthodontic Treatment: A Randomized Controlled Trial

INTRODUCTION

This study investigated the effectiveness of titanium tetrafluoride (TiF4) varnish compared to sodium fluoride (NaF) varnish for preventing and remineralizing white spot lesions (WSLs) in individuals undergoing orthodontic treatment.

METHODS

This randomized, placebo-controlled, and double-blinded study was conducted with sixty-five adolescents who were selected based on caries activity and then randomized into three parallel groups: G1 (placebo varnish), G2 (5% NaF varnish), and G3 (4% TiF4 varnish). Volunteers received varnish application weekly for the first 4 weeks, after 6 (T1) and 12 (T2) months. The measured outcomes included prevention of new WSLs and reversal/progression of WSLs, assessed by Nyvad and International Caries Detection and Assessment System (ICDAS) indices, as well as quantitative light-induced fluorescence. χ2, ANOVA, and Kruskall-Wallis tests were applied. The level of significance was set at 0.05, and post hoc Bonferroni test for p values was performed to correct for multiple comparisons.

RESULTS

1,274 teeth were included; 70.5% were Nyvad 0, and 29.5% were Nyvad 1, with no differences between the groups at baseline (T0). Regarding ICDAS, 70.5% were ICDAS 0, 21.6% were ICDAS 1, and 7.9% were ICDAS 2. G1 showed an increasing prevalence of WSLs at T1 and maintained stable at T2; G2 exhibited a decline at T2, while G3 experienced a decrease at T1 and T2 (p < 0.01). Incidence of WSLs at T2 was 10.2% (G1), 5.6% (G2), and 1.4% (G3). The percentage of teeth initially scored as Nyvad 0 that progressed to Nyvad 1 was 13%, 6.8%, and 1% for G1, G2, and G3, respectively. Conversely, the percentage of teeth initially scored as Nyvad 1 that regressed to Nyvad 0 or Nyvad 2 (T0-T2) was 14%, 49.3%, and 74.4%, respectively (p < 0.001). As for the ICDAS index, regression was observed in 6.5%, 17.8%, and 24%, while progression was observed in 14.9%, 7.7% and 0.9% for G1, G2, and G3, respectively (p < 0.001). Significant differences among the 3 groups for integrated fluorescence loss (mean ± SD, G1: -14.28 ± 9.47, G2: -11.10 ± 11.49, and G3: -6.77 ± 11.00) were found at T2 (p < 0.01).

CONCLUSION

Both varnishes demonstrated the ability to prevent and remineralize WSLs. However, TiF4 varnish exhibited the most effective control over WSLs during the 12-month orthodontic treatment.

Antibacterial coating of orthodontic elastomeric ligatures with silver and bismuth nanofilms by magnetron sputtering: A feasibility study

OBJECTIVES

Magnetron sputtering was evaluated to equip surfaces of orthodontic elastomeric ligatures with silver and bismuth nanofilms.

MATERIAL AND METHODS

Antibacterial properties were evaluated by the adhesion of Streptococcus mutans. Polyurethane-based elastomeric ligatures were coated with silver and bismuth nanofilms via direct current magnetron sputtering. Surface roughness (Ra ) and surface-free energy (SFE) were assessed. Coated specimens were incubated with S. mutans for 2 h. Adhering bacteria were visualized by Hoechst staining and quantified by an ATP-based luminescence assay. One-way analysis of variance with Tukey post hoc testing and Pearson correlation analysis were performed (p < .05) to relate bacterial adhesion to surface roughness and surface-free energy.

RESULTS

Elastomeric ligatures were successfully coated with silver and bismuth nanofilms. Ra was significantly reduced by silver coating. Silver and bismuth coatings showed significantly higher SFE than controls. Adhesion of S. mutans was significantly decreased by silver coating. No correlation between bacterial adhesion and SFE was found. Correlation between bacterial adhesion and Ra was positive but not statistically significant.

CONCLUSIONS

Magnetron sputtering proved to be a feasible method to equip orthodontic elastomeric ligatures with silver and bismuth nanofilms. Silver coatings of elastomeric ligatures may reduce white spots and carious lesions in orthodontic patients. Future research is required to stabilize coatings.

Biofilm volume and acidification within initial biofilms formed in situ on buccally and palatally exposed bracket material

PURPOSE

Acidification by bacterial biofilms at the bracket/tooth interface is one of the most common problems in fixed orthodontic treatments, which can lead to white spot lesions (WSL) and caries. As lingual brackets were shown to exhibit reduced WSL formation clinically, the aim of this in situ study was to compare initial intraoral biofilm formation and acidification on bracket-like specimens placed buccally and palatally in the upper jaw as a possible cause for this observation.

METHODS

Intraoral biofilm was collected from splints equipped with buccally and palatally exposed test specimens, which were worn by 12 volunteers for a total of 48 h. The test specimens consisted of standard bracket material cylinders on top of a hydroxyapatite disc to represent the bracket/tooth interface. They were analyzed for three-dimensional biofilm volume and live/dead distribution by fluorescence staining and confocal laser scanning microscopy as well as for acidification by fluorescence-based pH ratiometry.

RESULTS

Similar general biofilm morphology with regard to volume and viability could be detected for buccally and palatally exposed specimens. For pH values, biofilms from both positions showed increased acidification at the bottom layer. Interestingly, the pH value at the top layers of the biofilms was slightly lower on palatally than on buccally exposed specimens, which may likely be due to anatomic conditions.

CONCLUSION

Based on the results of this study, initial intraoral biofilm formation and acidification is almost similar on the bracket material/biomimetic tooth interface when placed buccally or palatally in the upper jaw. As lingual brackets were shown to exhibit reduced WSL formation clinically, future studies should investigate further factors like bracket geometry.

Influence of the orthodontic bonding procedure on biofilm formation

INTRODUCTION

In orthodontics, white spot lesions are a persistent and widespread problem caused by the demineralization of buccal tooth surfaces around bonded brackets. The remaining adhesive around the brackets leads to surface roughness, which might contribute to demineralization. The present in vitro study aimed to compare a conventional and a modern adhesive system (APC Flash-Free technology) for orthodontic brackets with regard to the adhesion of Streptococcus sobrinus, a leading caries pathogen.

METHODS

This in vitro study included 20 premolar teeth and compared 10 APC Flash-Free adhesive-coated ceramic brackets (FF)with 10 conventionally bonded (CB) ceramic clarity brackets. Specimens were incubated in an S. sobrinus suspension for 3 h. To evaluate the bacterial formation, samples were analysed with a scanning electron microscope (SEM). Imaging software was used to quantify and statistically compare percentage values of colonization (PVC) in both groups' adhesion and transition areas.

RESULTS

We found a significant difference in biofilm formation between the groups for the adhesive and transition areas. PVC in the adhesive area was approximately 10.3-fold greater for the CB group compared with the FF group (median: 3.2 vs 0.31; P < 0.0001). For the transition area, median PVC was approximately 2.4-fold greater for the CB group compared with the FF group (median: 53.17 vs 22.11; P < 0.01).

CONCLUSIONS

There was a significantly lower level of S. sobrinus formation around the FF bracket system than there was surrounding the conventionally bonded group. This study suggests that the FF adhesive bracket system can help reduce the occurrence of bacterial growth around orthodontic brackets.

Antibacterial properties and abrasion-stability: Development of a novel silver-compound material for orthodontic bracket application

PURPOSE

Bacteria-induced white spot lesions are a common side effect of modern orthodontic treatment. Therefore, there is a need for novel orthodontic bracket materials with antibacterial properties that also resist long-term abrasion. The aim of this study was to investigate the abrasion-stable antibacterial properties of a newly developed, thoroughly silver-infiltrated material for orthodontic bracket application in an in situ experiment.

METHODS

To generate the novel material, silver was vacuum-infiltrated into a sintered porous tungsten matrix. A tooth brushing simulation machine was used to perform abrasion equal to 2 years of tooth brushing. The material was characterized by energy dispersive X‑ray (EDX) analysis and roughness measurement. To test for antibacterial properties in situ, individual occlusal splints equipped with specimens were worn intraorally by 12 periodontal healthy patients for 48 h. After fluorescence staining, the quantitative biofilm volume and live/dead distribution of the initial biofilm formation were analyzed by confocal laser scanning microscopy (CLSM).

RESULTS

Silver was infiltrated homogeneously throughout the tungsten matrix. Toothbrush abrasion only slightly reduced the material's thickness similar to conventional stainless steel bracket material and did not alter surface roughness. The new silver-modified material showed significantly reduced biofilm accumulation in situ. The effect was maintained even after abrasion.

CONCLUSION

A promising, novel silver-infiltrated abrasion-stable material for use as orthodontic brackets, which also exhibit strong antibacterial properties on in situ grown oral biofilms, was developed. The strong antibacterial properties were maintained even after surface abrasion simulated with long-term toothbrushing.

Bond strength, degree of conversion, and microorganism adhesion using different bracket-to-enamel bonding protocols

PURPOSE

This study aimed to evaluate the effect of bonding protocols and the type of orthodontic resin on the adhesion of microorganisms, degree of conversion (DC), and shear bond strength (SBS) of metallic brackets to enamel.

METHODS

A total of 60 bovine incisors were prepared and randomly divided into 6 groups (n = 10): "bonding protocol" (A: phosphoric acid; AXT: A+Transbond™ XT primer adhesive [all Transbond™ products from 3M Unitek, Monrovia, CA, USA]; and SE: Transbond™ Plus Self Etching Primer) and "orthodontic resin" (XT: Transbond™ XT adhesive paste and CC: Transbond™ Plus Color Change). After bonding, the samples were subjected to thermocycling (5000 cycles) and to the SBS test. Bond failures were classified according to the adhesive remnant index (ARI). Next, 60 enamel blocks were sterilized in ethylene oxide in order to perform the CFU (Streptococcus mutans) assay in vitro to analyze the colony forming units (CFU/mL). Then, 60 discs of each orthodontic resin were made to measure the DC. The SBS (MPa), CFU/mL, and DC (%) data were statistically analyzed by two-way analysis of variance and Tukey's test (5%) was performed for the DC.

RESULTS

CFU and SBS revealed no significance for all factors (P > 0.05). Tukey's test showed that A_XT (acid+Transbond™ XT adhesive paste) presented the highest DC (70.38% ± 10.5), while AXT_XT (acid+Transbond™ XT primer adhesive+Transbond™ XT adhesive paste) showed the lowest (23.47% ± 10.4). An ARI score of 2 was more frequent for the CC resin and an ARI score of 4 for the XT resin.

CONCLUSION

The CC resin does not reduce adhesion of S. mutans around orthodontic brackets and the bonding protocol did not influence the SBS, although the SE and A_XT groups contributed to a better DC.

Photobiomodulation therapy assisted orthodontic tooth movement: potential implications, challenges, and new perspectives

Over the past decade, dramatic progress has been made in dental research areas involving laser therapy. The photobiomodulatory effect of laser light regulates the behavior of periodontal tissues and promotes damaged tissues to heal faster. Additionally, photobiomodulation therapy (PBMT), a non-invasive treatment, when applied in orthodontics, contributes to alleviating pain and reducing inflammation induced by orthodontic forces, along with improving tissue healing processes. Moreover, PBMT is attracting more attention as a possible approach to prevent the incidence of orthodontically induced inflammatory root resorption (OIIRR) during orthodontic treatment (OT) due to its capacity to modulate inflammatory, apoptotic, and anti-antioxidant responses. However, a systematic review revealed that PBMT has only a moderate grade of evidence-based effectiveness during orthodontic tooth movement (OTM) in relation to OIIRR, casting doubt on its beneficial effects. In PBMT-assisted orthodontics, delivering sufficient energy to the tooth root to achieve optimal stimulation is challenging due to the exponential attenuation of light penetration in periodontal tissues. The penetration of light to the root surface is another crucial unknown factor. Both the penetration depth and distribution of light in periodontal tissues are unknown. Thus, advanced approaches specific to orthodontic application of PBMT need to be established to overcome these limitations. This review explores possibilities for improving the application and effectiveness of PBMT during OTM. The aim was to investigate the current evidence related to the underlying mechanisms of action of PBMT on various periodontal tissues and cells, with a special focus on immunomodulatory effects during OTM.

[Characteristics of white spot lesions associated with orthodontic treatment: a review]

Introduction

The purpose of this literature review is to provide scientific evidence on the characteristics of white spot lesions (WSL) during orthodontic treatment, their incidence, prevalence, risk factors related to their development, progression, and regression, as well as explain the most used diagnostic methods.

Materials and methods

An exhaustive search was carried out in the databases of Pubmed, Scopus, Science Direct and Embase up to the date of November 30, 2022. Cross-sectional studies that evaluated white spot lesions before and after orthodontic treatments were included. Two researchers carefully selected the articles evaluated and analyzed different key topics on the subject.

Results

It was found that the prevalence and incidence of white spots during orthodontic treatment varies widely depending on the diagnostic method used, the type of orthodontic technique used and the time of orthodontic treatment. The incidence of white spot lesions is highest in patients treated with conventional braces, followed by those who used self-ligating braces, and was lowest in patients who used aligners. The most affected teeth are the upper lateral incisors and upper maxillary canines at the level of the gingival third.

Conclusions

The incidence of white spots is associated with orthodontic treatment, being closely related to the treatment technique used and the treatment time. There is a regression of the LMB during the first year after removal of the appliance.

Methylene Blue Penetration of Resin Infiltration and Resin Sealant in Artificial White-Spot Lesions

OBJECTIVE

 This study determined the potency of resin infiltrations and resin sealant in impeding microleakage on artificial white-spot lesions (AWL) by methylene blue penetration.

MATERIALS AND METHODS

 Eighty AWL specimens were randomly separated into two groups for water storage for 24 hours (groups 1-4) and 20,000 cycles of thermocycling (TC) (groups 5-8). Each group was then separated into four subgroups (n = 10) based on the AWL surface treatments: (1) no Tx, (2) treated with resin infiltration (ICON, DMG, Hamburg, Germany), (3) treated with resin infiltration (Surface pre-reacted glass-ionomer (S-PRG) barrier coat, SHOFU, Kyoto, Japan), (4) treated with resin sealant (Clinpro sealant, 3M ESPE, Minnesota, United States). Nail varnish was covered to all samples, with the exception of a 4 × 4 mm2 patch on the buccal measurement region, which was subsequently submerged in a 2% methylene blue solution and cut into buccolingual sections. Stereomicroscope measurements were used to calculate methylene blue penetration scores.

STATISTICAL ANALYSIS

 The Kruskal-Wallis test and the Bonferroni post-hoc correction were performed to evaluate the data.

RESULTS

 Application of resin infiltrants and resin sealant reduced microleakage in AWL by methylene penetration both before and after thermal cycling. In addition, group 6 (ICON + TC) and group 7 (S-PRG + TC) had a significantly different value from group 8 (sealant + TC).

CONCLUSION

 Both the resin infiltration approach and the resin sealant seem to help seal AWL and might perhaps offer long-term defense against microleakage in AWL caused by methylene blue penetration. The greatest sealing and defense for microleakage in AWL were demonstrated by the resin infiltrations.

Effects of reducing excess dental adhesive on bacterial adhesion in the bracket periphery

OBJECTIVES

White spot lesions are one of the most common side effects of orthodontic therapy with a multibracket appliance and may indicate a preliminary stage of caries, also known as initial caries. Several approaches may be utilized to prevent these lesions, such as reducing bacterial adhesion in the area surrounding the bracket. This bacterial colonization can be adversely affected by a number of local characteristics. In this context, the effects of excess dental adhesive in the bracket periphery were investigated by comparing a conventional bracket system with the APC flash-free bracket system.

MATERIALS AND METHODS

Both bracket systems were applied to 24 extracted human premolars, and bacterial adhesion with Streptoccocus sobrinus (S. sobrinus) was performed for 24 h, 48 h, 7 d, and 14 d. After incubation, bacterial colonization was examined in specific areas by electron microscopy.

RESULTS

Overall, significantly fewer bacterial colonies were found in the adhesive area around the APC flash-free brackets (n = 507 ± 13 bacteria) than the conventionally bonded bracket systems (n = 850 ± 56 bacteria). This is a significant difference (**p = 0.004). However, APC flash-free brackets tend to create marginal gaps with more bacterial adhesion in this area than conventional bracket systems (n = 265 ± 31 bacteria). This bacterial accumulation in the marginal-gap area is also significant (*p = 0.029).

CONCLUSION

A smooth adhesive surface with minimal adhesive excess is beneficial for reducing bacterial adhesion but also poses a risk of marginal gap formation with subsequent bacterial colonization, which can potentially trigger carious lesions.

CLINICAL RELEVANCE

To reduce bacterial adhesion, the APC flash-free bracket adhesive system with low adhesive excess might be beneficial. APC flash-free brackets reduce the bacterial colonization in the bracket environment. A lower number of bacteria can minimize white spot lesions in the bracket environment. APC flash-free brackets tend to form marginal gaps between the bracket adhesive and the tooth.

Pre-treatment oral microbiome analysis and salivary Stephan curve kinetics in white spot lesion development in orthodontic patients wearing fixed appliances. A pilot study

BACKGROUND

White spot lesions (WSLs) are a formidable challenge during orthodontic treatment, affecting patients regardless of oral hygiene. Multifactorial in nature, amongst potential contributors to their development are the microbiome and salivary pH. The aim of our pilot study is to determine if pre-treatment differences in salivary Stephan curve kinetics and salivary microbiome features correlate with WSL development in orthodontic patients with fixed appliances. We hypothesize that non-oral hygiene determined differences in saliva could be predictive of WSL formation in this patient population through analysis of salivary Stephan curve kinetics, and that these differences would further manifest as changes in the oral microbiome.

METHODS

In this prospective cohort study, twenty patients with initial simplified oral hygiene index scores of "good" that were planning to undergo orthodontic treatment with self-ligating fixed appliances for at least 12 months were enrolled. At pre-treatment stage, saliva was collected for microbiome analysis, and at 15-minute intervals after a sucrose rinse over 45 min for Stephan curve kinetics.

RESULTS

50% of patients developed a mean 5.7 (SEM: 1.2) WSLs. There were no differences in saliva microbiome species richness, Shannon alpha diversity or beta diversity between the groups. Capnocytophaga sputigena exclusively and Prevotella melaninogenica predominantly were found in WSL patients, while Streptococcus australis was negatively correlated with WSL development. Streptococcus mitis and Streptococcus anginosus were primarily present in healthy patients. There was no evidence to support the primary hypothesis.

CONCLUSIONS

While there were no differences in salivary pH or restitution kinetics following a sucrose challenge and no global microbial differences in WSL developers, our data showed change in salivary pH at 5 min associated with an abundance of acid-producing bacteria in saliva. The results suggest salivary pH modulation as a management strategy to inhibit the abundance of caries initiators. Our study may have uncovered the earliest predecessors to WSL/caries development.

White Spots: Prevention in Orthodontics-Systematic Review of the Literature

Early-stage dental demineralization, called white spots (WS), get their name from the characteristic colour that enamel takes on due to the acid attack of salivary cariogenic bacteria. They are often associated with fixed orthodontic therapy (FOT) and, if left untreated, evolve into caries with repercussions on oral health and dental aesthetics. This review aims to identify the most effective prophylaxis strategies to prevent WS during FOT. The search for the reviewed studies was conducted on the Pubmed, Scopus, and Web of Science databases, selecting English-only articles published in the 5 years from January 2018 to January 2023. The keywords used were "WS" and "fixed orthodontic*", using "AND" as the Boolean operator. A total of 16 studies were included for qualitative analysis. Prevention begins with maintaining proper oral hygiene; fluoride in toothpaste, mouthwashes, gels, varnishes, and sealants can be added to prophylaxis and used regularly. Using a laser in combination with fluoride helps prevent the occurrence of WS and assists in the repair processes of initial lesions. Further studies are needed to establish international guidelines for preventing WS in orthodontically treated patients.

Twenty-year follow-up of functional treatment with a bionator appliance (part 2): a retrospective cephalometric analysis of skeletal and dentoskeletal changes

OBJECTIVES

To investigate skeletal and dentoskeletal changes 20 years after bionator treatment.

MATERIALS AND METHODS

Analog lateral cephalograms of 18 subjects treated with a bionator appliance during growth were digitized with a transmitted light scanner. Inclusion criteria were: increased overjet (≥4 mm), skeletal Class II, available lateral cephalograms before (T0), after (T1), and 20 years after (T2) treatment with only a Bionator. To assess standard cephalometric parameters, the software ivoris analyze was used. Data were analyzed using Friedman's two-way analysis of variance by ranks followed by Dunn's post hoc tests (P ≤ .05).

RESULTS

During therapy (T0-T1), ANB decreased significantly by 1.9° and remained unchanged long term. SNA slightly decreased (-0.6°) during treatment, SNB and SNPg increased (+1.4°, +1.7°). All three parameters showed a significant increase at T2 (+1.2°, +1.6°, +1.6°). Vertical measurements (ML-NL, ML-NSL, NL-NSL) remained almost unchanged during therapy. NL-NSL also was unchanged during the long-term interval; ML-NSL and ML-NL decreased significantly (-3.4°, -4.9°). During treatment, the maxillary incisors retroclined (OK1-NL: -1.6°, OK1-NA: -0.6°), the mandibular incisors proclined (UK1-ML: +3.5°, UK1-NB: +4.9°), neither significantly. Long term, there was a nonsignificant tendency toward proclination of upper (OK1-NL: +0.1°, OK1-NA: +0.7°) and retroclination of lower incisors (UK1-ML: -1.5°, UK1-NB: -5°).

CONCLUSIONS

Changes of ANB after bionator treatment without additional fixed appliances remained stable after 20 years. The observed long-term changes are probably consequences of well-known physiological and age-related processes.

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.

Evaluation of the Demineralization Development around Different Types of Orthodontic Brackets

The aim of this study was to compare the demineralizations of the enamel surfaces around different types of orthodontic brackets in an artificial cariogenic environment. A total of 90 extracted human maxillary first premolar teeth were used in this in vitro study. The teeth were divided into 6 groups, 5 study and 1 control, each consisting of 15 samples. Victory metal, Gemini metal, Clarity self-ligating ceramic, APC Clarity Advanced ceramic and Clarity Advanced ceramic brackets (3M Unitek, Monrovia, Calif) used in the study groups were bonded to the teeth with the direct technique. The gingival, occlusal and proximal enamel surfaces adjacent to the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany) (T0). Then, the teeth were placed in a cariogenic suspension environment containing Streptococcus mutans, sucrose and artificial saliva. The teeth were removed from the cariogenic suspension at the end of 28 days. Enamel surfaces were remeasured with DIAGNOdent and the values were recorded (T1). Whether the obtained data were homogeneously distributed or not was determined by the Kolmogorov-Smirnov test, within-group comparisons were performed with the Wilcoxon test, and between-group comparisons were performed with Mann-Whitney U and Kruskal-Wallis tests. Significance level was accepted as p < 0.05. In all groups, the demineralization values of the enamel surfaces in the gingival, proximal and occlusal surfaces adjacent to the brackets were significantly higher in the T1 period than in the T0 period (p < 0.05). In the T1 period of Gemini metal, Clarity self-ligating ceramic and Clarity advanced ceramic bracket groups, the demineralization values of the proximal enamel surfaces were found to be significantly higher than the Victory metal and APC Clarity Advanced ceramic bracket groups (p < 0.05). In the T1 period, the demineralization values of the occlusal enamel surfaces of the Victory metal, APC Clarity Advanced ceramic bracket groups and control group were significantly lower than the Gemini metal, Clarity self-ligating ceramic and Clarity Advanced ceramic bracket groups (p < 0.05). Significant increases in enamel demineralization values were observed as a consequence of increased retention areas for microbial dental plaque on enamel surfaces adjacent to the bracket. Considering the importance of minimizing enamel demineralization in fixed orthodontic treatments, less enamel demineralization in Victory metal and APC Clarity Advanced ceramic bracket groups showed that these brackets can be preferred in patients with poor oral hygiene.

METHODS FOR DIAGNOSING DENTAL CARIES LESIONS

Tooth decay (dental caries) commonly occurs throughout the world and is one of the most widespread infectious diseases of lifestyle, globally affecting all age groups; up to 90% schoolchildren and almost 100% adults in both developing and developed countries. When left untreated, it can lead to disease outbreaks resulting in advere-health and life-threatening conditions such as endocarditis or sepsis. Undoubtedly, basic measures are thus required in both dental and GP practice to ensure that dental caries are detected early. This article presents the various diagnostic methods used to identify these disease outbreaks.

In vitro surface analysis of the brushing resistance of orthodontic sealants using two different profilometric evaluation methods

The enamel can be protected by applying orthodontic sealants at the bracket base to avoid the development of white spot lesions caused by inadequate oral hygiene. The aim of this study was to investigate the mechanical resistance of five commonly used orthodontic sealants against brushing in comparison to a positive group. Hydroxyapatite discs were bonded with a metal bracket and a piece of arch-wire was ligated in order to simulate a daily clinical situation (n = 48). Samples were divided into 6 groups of respectively 8 specimens. Sealants were applied around the bracket base according to manufacturer's instructions. Following sealants were used: Group 1: Pro Seal (Reliance Orthodontic Products, Itasca, Illinois, USA); 2: Light Bond (Reliance Orthodontic Products, Itasca, Illinois, USA); 3: ClinproXT Varnish (3M ESPE, Seefeld, Germany); 4: ProtectoCaF2 Nano (BonaDent GmbH, Frankfurt am Main, Germany); 5: Fluor Protector and 6: Tetric EvoFlow (both Ivoclar Vivadent AG, Schaan Liechtenstein). Tooth brushing were simulated for 6 weeks and 6 months with an electric toothbrush. The sealant thickness was measured by mechanical (MP) and optical profilometry (OP) at baseline, after 6 weeks and after 6 months of brushing. Statistical analysis was performed according to two mixed linear models and post hoc Tukey-Kramer comparisons. The significance level was set at 5% (α ≤ 0.05). Pro Seal (MP: 9%; OP: 22%) and Light Bond (MP: 19%; OP: 16%) showed the lowest changes in sealant thickness after 6 months of simulated brushing. ClinproXT Varnish and Tetric EvoFlow recorded no statistically significant results (p > 0.05). The fluoride varnishes ProtectoCaF2 Nano and Fluor Protector could not be conclusively evaluated since the thickness of the sealants could not be determined at baseline. The results of both evaluation methods MP and OP are in good agreement. Pro Seal and Light Bond were resistant against tooth brushing and were able to adequately keep the bracket environment sealed even after 6 months. The two different measuring methods, MP and OP, provide a precise impression of the changes in the surface.

The Influence of 2-Methacryloyloxyethyl Phosphorylcholine Polymer Materials on Orthodontic Friction and Attachment of Oral Bacteria

There is no clinical evidence of the usage of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers in dental practice. We performed in vitro studies to determine whether the application of an MPC coating to stainless steel orthodontic wires confers low-friction and antimicrobial properties to these wires. The friction test on MPC-coated wires was performed using a precision universal/tensile tester. MPC polymer was coated on a 50 × 50 mm stainless steel plate, and samples were assessed using an antimicrobial activity test. To verify the effect of MPC polymer-treated wires on experimental tooth movement models in vitro, examinations were performed on typodonts to determine the improvement in tooth movement efficiency. The polymer treatment wire groups demonstrated significantly enhanced tooth movement compared with the untreated wire groups, at both 50 g and 100 g traction forces. The results indicated that MPC coating inhibited the attachment of oral bacteria, such as Streptococcus mutans, on a stainless steel plate. Additionally, the coating seemed to improve the efficiency of tooth movement by reducing the occurrence of friction. The application of an MPC coating onto stainless steel wires, which are used as orthodontic materials, may reduce static friction and bacterial adherence to the oral cavity and improve tooth movement.

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

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

Evaluation of tooth demineralization using laser-fluorescence in dental school patients undergoing orthodontic treatment: A clinical study

BACKGROUND

Adverse effects can occur during orthodontic treatment.

OBJECTIVE

To evaluate the relationship between prevalence and severity of enamel demineralization using a laser-fluorescence device, with length of orthodontic treatment time.

METHOD

A cross-sectional study was conducted in 60 patients in a university orthodontic clinic. A clinical examination to establish demineralization at four sites on each tooth (premolar to premolar) was performed using the DIAGNOdent pen. The dependent variable was enamel demineralization, from which the prevalence (at least one affected site), extension (percentage of affected teeth) and adjusted average (average of the mean DIAGNOdent values per tooth) were calculated. The length of time for orthodontic treatment was determined in months. Various sociodemographic and clinical covariates were included.

RESULTS

Average number of months under orthodontic treatment was 26.37 ± 24.81 months. Prevalence of enamel demineralization was 80.0%, its extension was 21.9% ± 17.2 and adjusted average of DIAGNOdent values was 6.09 ± 1.75. By quadrant, the teeth most affected were 14 (34.4%), 24 (25.0%), 31 (30.2%) and 44 (33.3%). No significant relationship (p> 0.05) was observed between enamel demineralization and length of time under orthodontic treatment.

CONCLUSIONS

A high prevalence of dental demineralization was observed. In this sample, no relationship was observed between months under treatment and dental demineralization, or with other variables included in the study.

Remineralisation capability of silver diamine fluoride in artificial enamel lesions on smooth surfaces using quantitative light-induced fluorescence measurements in-vitro

Enamel demineralisation can develop on smooth surfaces as an undesirable side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the ability of 38% silver diamine fluoride in remineralisation (as estimated by fluorescence gain) of artificial initial lesions in smooth surfaces of human enamel. The smooth surfaces of 50 human tooth samples were artificially demineralised and 45 samples were allocated randomly into three groups receiving a single treatment with a varnish: group I: Riva Star (silver diamine fluoride, SDF), group II: Bifluorid 12 (NaF, CaF₂), and group III: Cervitec F (CHX, CPC, NH₄F). Five samples were assigned as a negative control group without treatment. All samples were exposed to pH-cycling for 28 days. Fluorescence behavior was measured using Quantitative light-induced fluorescence before and after demineralisation and up to four weeks on a weekly basis. Analysis of variance (ANOVA) with Tukey–Kramer post-hoc tests and repeated measures ANOVA were used for statistical evaluation (α = 0.05). After demineralisation, all samples showed mean ΔF of − 16.22% ± 4.35, without significance differences between the fluorescence behaviour of the samples (p = 0.251). After 28 days group comparison showed a statistically significant difference (p = 0.034) for ΔF values: the lowest fluorescence values were found in group I (SDF, mean ΔF − 16.47 ± 6.08) with a significant difference compared to group III (Cervitec F, mean ΔF − 11.71 ± 4.83). In group II (Bifluorid 12) mean ΔF value was − 15.55 ± 2.15) without statistically significant differences to groups I and III. The fluorescence behaviour of SDF varnish on smooth surfaces with artificial initial enamel lesions was significantly lower compared to Cervitec F varnish after short time use.

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.

White spot lesions during orthodontic clear aligner therapy: A scoping review

BACKGROUND:

OBJECTIVES:

TYPES OF STUDIES REVIEWED:

RESULTS:

PRACTICAL IMPLICATIONS:

A novel method quantifying caries following orthodontic treatment

This retrospective pilot study used a newly developed evaluation tool to assess the prevalence and incidence of White Spot Lesions (WSL) before and after multibracket appliance (MB) therapy. Digital photographs of 121 adolescent patients (63 ♂, 58 ♀) with metal brackets were analyzed retrospectively before and after MB therapy. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated using the Enamel Decalcification Index (EDI) by Banks and Richmond (Eur J Orthod, 16(1):19-25, 1994, levels 0-3) and a specially developed digitally scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Before MB, 69.4% of the patients presented at least one WSL and 97.5% after, an increase of 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1-3. After MB, 51.8% of the TS featured WSL. 18.2% of the TS showed a WSL to the extent of ≥ 20-100% before and 52.3% after MB. The incidence in the UJ (71-79%) as well as the LJ (64-76%) was highest for the first and second premolars and lowest for LJ incisors (22-35%). The probability for developing a new distal WSL is higher than developing gingival, mesial or occlusal WSL. Labial MB therapy drastically increases the risk of developing WSL. We verified a concise quantification of the extent of labial WSL with the evaluation index.

Incorporation of Arginine to Commercial Orthodontic Light-Cured Resin Cements-Physical, Adhesive, and Antibacterial Properties

(1) Background: The amino acid arginine is now receiving great attention due to its potential anti-caries benefits. The purpose of this in vitro study was to evaluate the shear bond strength (SBS), ultimate tensile strength (UTS), and antimicrobial potential (CFU) of two arginine-containing orthodontic resin cements. (2) Methods: Forty bovine incisors were separated into four groups (n = 10): Orthocem, Orthocem + arginine (2.5 wt%), Transbond XT, and Transbond XT + arginine (2.5 wt%). The brackets were fixed to the flat surface of the enamel, and after 24 h the SBS was evaluated using the universal testing machine (Instron). For the UTS test, hourglass samples (n = 10) were made and tested in a mini-testing machine (OM-100, Odeme). For the antibacterial test (colony forming unit-CFU), six cement discs from each group were made and exposed to Streptococcus mutans UA159 biofilm for 7 days. The microbiological experiment was performed by serial and triplicate dilutions. The data from each test were statistically analyzed using a two-way ANOVA, followed by Tukey's test (α = 0.05). (3) Results: The enamel SBS mean values of Transbond XT were statistically higher than those of Orthocem, both with and without arginine (p = 0.02033). There was no significant difference in the SBS mean values between the orthodontic resin cements, either with or without arginine (p = 0.29869). The UTS of the Transbond XT was statistically higher than the Orthocem, but the addition of arginine at 2.5 wt% did not influence the UTS for either resin cement. The Orthocem + arginine orthodontic resin cement was able to significantly reduce S. mutans growth, but no difference was observed for the Transbond XT (p = 0.03439). (4) Conclusion: The incorporation of arginine to commercial orthodontic resin cements may be an efficient preventive strategy to reduce bacterial growth without compromising their adhesive and mechanical properties.

Use of bioluminescence measurements for detection of artificial demineralization adjacent to orthodontic brackets

PURPOSE

Enamel demineralization can occur as a side effect during orthodontic treatment with fixed appliances and should be detected as early as possible. A new approach to assess demineralization is a system consisting of a photosensitive protein that binds to free calcium ions at the enamel surface. A camera is then used to visualize the bioluminescence spots. This in vitro study aimed to evaluate the ability of the bioluminescence technology to assess artificially demineralized enamel adjacent to various orthodontic brackets.

METHODS

In all, 108 human enamel samples were allocated randomly to groups with different orthodontic bracket material: stainless steel, titanium, ceramic. Initial lesions were created adjacent to the brackets. The samples were assessed by bioluminescence before and after demineralization. Images were assessed for presence of bioluminescence spots (yes/no). To quantify the bioluminescence measurements, the images' pixel values (P) were calculated within a defined area (F) adjacent to each bracket before and after demineralization. Quantitative light-induced fluorescence measurements (ΔF, ΔQ) were performed as the reference standard for demineralization.

RESULTS

After demineralization, bioluminescence spots were visible (yes/no decision) in 87% of the samples. The pixel analysis of the bioluminescence spots showed significantly higher pixel values after demineralization compared to baseline (p < 0.0001). The bracket material had no influence on the bioluminescence measurements. All samples showed fluorescence loss with a median ΔF of -9.52% (±3.15) and a median ΔQ of -1.01% × mm² (±3.34), respectively.

CONCLUSION

The bioluminescence technology is a promising tool to demonstrate demineralization adjacent to different orthodontic brackets in vitro.

Proteome difference among the salivary proteins adsorbed onto metallic orthodontic brackets and hydroxyapatite discs

The aim of this study was to investigate the atomic composition and the proteome of the salivary proteins adsorbed on the surface of orthodontic metallic bracket. For this, the atomic composition of orthodontic metallic brackets was analyzed with X-ray Photoelectron Spectroscopy (XPS). The acquired bracket pellicle was characterized after brackets were immersed in human whole saliva supernatant for 2 hours at 37°C. Hydroxyapatite (HA) discs were used as a control. Acquired pellicle was harvested from the HA discs (n = 12) and from the metallic brackets (n = 12). Proteomics based on mass spectrometry technology was used for salivary protein identification and characterization. Results showed that most of the proteins adsorbed on the surface of orthodontic metallic brackets and on the HA discs were identified specifically to each group, indicating a small overlapping between the salivary proteins on each study group. A total of 311 proteins present on the HA discs were unique to this group while 253 proteins were unique to metallic brackets, and only 45 proteins were common to the two groups. Even though most proteins were unique to each study group, proteins related to antimicrobial activity, lubrication, and remineralization were present in both groups. These findings demonstrate that the salivary proteins adsorbed on the bracket surface are dependent on the material molecular composition.

Shear bond strength of orthodontic brackets on intact and demineralized enamel after application of resin infiltrant, fluoride varnish and casein phosphopeptide-amorphous calcium phosphate remineralizing agents: in-vitro study

OBJECTIVE

To evaluate the effects of remineralizing agents on the shear bond strength (SBS) of orthodontic brackets bonded to intact and demineralized enamel.

MATERIAL AND METHODS

In this in-vitro study, 160 human premolars were divided into 8 groups, including group 1 with intact enamel as the positive control, group 2 with demineralized enamel as the negative control, groups 3-5 treated with fluoride varnish, Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) and resin infiltrant on intact enamel, and groups 6-8 treated with the same agents on demineralized enamel. Brackets were bonded using the conventional method, and the samples were thermocycled. SBS of the brackets was measured using a universal testing machine, and the adhesive remnant index (ARI) was assessed. Data were analysed with one-way ANOVA and post hoc statistical test at the significance level of 0.05.

RESULTS

SBS of the brackets in all groups with intact enamel was higher than that of their counterparts on demineralized enamel, which was only significantly different between groups 1 and 2 (P-value<0.001). SBS values of groups 7 and 8 were not significantly different from group 1 (P-value=1), yet the application of fluoride varnish on both intact (P-value=0.091) and demineralized enamel (P-value<0.001) created less SBS than in group 1.

CONCLUSIONS

All pre-treatment methods increased SBS of the brackets bonded to demineralized enamel, yet only the resin infiltrant and CPP-ACP produced SBS similar to that of intact enamel. Also, the use of fluoride varnish on intact enamel significantly reduced SBS.

Effect of adrenaline and noradrenaline on biofilm formation and virulence factors of Streptococcus mutans UA159

OBJECTIVES

To evaluate in vitro the effects of adrenaline and noradrenaline on the biofilm formation on orthodontic brackets, acid production and expression of virulence genes of Streptococcus mutans UA159 (S. mutans).

DESIGN

S. mutans UA159 biofilm was formed on orthodontic brackets under exposure to adrenaline (100 μM), noradrenaline (50 μM) or PBS solution (control group) in triptone-yeast extract with 1 % sucrose. After 24 h, biofilm formation was quantified through Colony Forming Units / mL (CFU/mL) and RNA was extracted to perform gene expression analysis through real-time reverse transcriptase-PCR (RT-qPCR). Evaluation of acid production was carried out on planktonic cultures for 6 h. One-way ANOVA followed by Tukey's test was carried to determine statistical difference. The level of significance was set at 5 %.

RESULTS

Catecholamines stimulated biofilm formation of S. mutans in orthodontic brackets (p < 0,05) but did not interfere with acid production (pH reduction) or the expression of the tested genes related to biofilm formation (gtfB, gtfC, gbpA, gbpB, gbpC, gbpD and brpA), aciduric (relA) and acidogenic properties (ldh).

CONCLUSIONS

The present study was the first to demonstrate that catecholamines can stimulate S. mutans UA159 biofilm formation. These findings can contribute to clarify the role of stress on bacterial metabolism and contribute to the understanding of a possible role on caries development, mainly in orthodontic patients.

The long observation in vitro of prevention effect of novel self-etching orthodontic adhesive modified with 2-methacryloxyethyl phosphorylcholine in enamel demineralization

The enamel demineralization is common in fixed orthodontics. Plaque accumulation around the bracket plays a critical role and could cause various degrees of white spot lesions (WSLs) on the surface of teeth. The 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer is a biological polymer with protein repellent and an anti-bacterial adhesion effects. In this study, the enamel shear bond strength (SBS) and protein repellent property in vitro of self-etching orthodontic adhesive with MPC were evaluated. It was found that the self-etching adhesive with 0-7.5%MPC met the orthodontic clinical requirement on the SBS values at three different points of time. The incorporation of 7.5%MPC significantly reduced the bacterial adhesion and total microorganism of the yield biofilm. Moreover, the MTT assay showed that the amount of plaque metabolism in 7.5%MPC was the lowest among the groups. To conclude, the novel protein repellent self-etching adhesive was able to inhibit biofilm formation efficiently and minimize enamel demineralization.

The Effect of Regime Oral-Hygiene Intervention on the Incidence of New White Spot Lesions in Teenagers Treated with Fixed Orthodontic Appliances

The present study aimed to evaluate the effect of the oral-hygiene regime on the incidence of enamel demineralization in young patients treated with fixed appliances. Research was conducted in a group of 144 patients aged 12–18 years, divided into 2 groups: orthodontically treated and control. The study was divided into three stages: before treatment (I), at 1 month (II), and at 6 months (III) for their follow-up. The International Caries Detection and Assessment System (ICDAS) was used for the visual assessment of white spot lesions (WSL). After 1 month, no new white spot lesions were observed. After 6 months of the treatment, new lesions were observed in 5% of the orthodontically treated patients and in 6% of the patients in the control group. New decalcifications were located on the proximal surfaces of the central incisors, first premolars, and first molars in the orthodontically treated group; and on the lateral incisors, first premolars, and first molars in the control group. We also observed new enamel demineralization on the vestibular surfaces of the canine and first premolar in the study group. The placement of a fixed appliance did not significantly affect teeth with the presence of new white spot lesions compared to the control group during 6 months of observation.

Abrasion of Pro Seal® and Opal® Seal™ by professional tooth cleaning protocols: results from an in vitro study and a randomized controlled trial

BACKGROUND

The integrity of orthodontic surface sealants after professional tooth cleaning (PTC) has previously only been evaluated in vitro. Recently, we have shown that optical coherence tomography (OCT) can successfully be used for the longitudinal assessments of sealant thickness in vitro and in vivo.

OBJECTIVES

Thus, the aim of the present study was to assess the sealant thickness after PTC in vitro and in vivo by OCT.

TRIAL DESIGN

Single-centre four-arm parallel-group randomized controlled trial.

METHODS

Ninety-six extracted human teeth were randomly assigned to the surface sealants Pro Seal® (PS) and Opal® Seal™ (OS) and to PTC protocols: (1) polishing with brush and prophy paste (Cleanic®) or (2) erythritol air-polishing. Sealant thickness was assessed by OCT immediately after application (baseline), after thermocycling and after polishing for totals of 5, 10, 15, 30, 60, 90, and 120 seconds. Additionally, a clinical trial was conducted. Therefore, using a split-mouth design, quadrants of 20 patients and PTC protocols were randomized by an external randomization centre using computer generated tables to assign the surface sealants and PTC protocols. Sealant thicknesses were analysed at baseline, before and after PTC. Due to the optical properties of sealants, a complete blinding was not feasible.

RESULTS

In vitro both sealants revealed significant layer thickness losses after both PTC protocols. PS lost 0.77 µm/s [95% CI (confidence interval): 0.67, 0.87] from air-polishing and 0.43 µm/s (95% CI: 0.37, 0.49) from polishing with brush while OS lost 0.44 µm/s (95% CI: 0.32, 0.55) from air-polishing and 0.79 µm/s (95% CI: 0.68, 0.89) from polishing with brush of layer thickness. Sealant thickness loss of was significantly higher after erythritol air-polishing for PS and after polishing with brush for OS. The results of a concurrent randomized controlled trial (RCT) were comparable to those achieved in the in vitro part of this study.

LIMITATIONS

Long-term surface sealant abrasion should be validated by additional RCTs.

CONCLUSIONS

For PTC on surface sealant treated teeth, low abrasive protocols should be used. Air-polishing should be avoided on PS protected teeth and polishing with brush on OS treated teeth.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03753256.

Association between fixed orthodontic treatment and dental caries: a 1-year longitudinal study

This longitudinal study aimed to assess the association between the use of fixed orthodontic appliances and the incidence/increment of active caries lesions in adolescents and young adults over a one-year period. A total of 135 10-30-year-old individuals were divided into two groups: Group G0 was composed of individuals who required orthodontic treatment, but who did not undergo fixed orthodontic therapy over the study period (n=70); Group G1 was composed of individuals who used a fixed orthodontic appliance for 1 year (n=65). Data collection included a questionnaire and clinical oral examinations (plaque index, gingival index, and dental caries index), performed at baseline and after 1 year. Caries examination was performed by a single calibrated examiner, after tooth cleaning and drying, and included the recording of non-cavitated and cavitated, inactive and active lesions of all tooth surfaces. Poisson regression models were used to assess the association between the group and the following study outcomes: incidence (binary variable) and increment (counting variable). The incidence of active caries lesions was 4.8% in G0 and 39.6% in G1. The mean increment of active caries lesions was 0.14 in G0 and 0.61 in G1. G1 showed a greater risk of developing active caries lesions than G0 (incidence analysis, adjusted IRR=9.48, 95%CI=2.62-34.30; increment analysis, adjusted IRR=4.13; 95%CI=1.94-8.79). In conclusion, this study showed that individuals undergoing fixed orthodontic therapy for 1 year had a significantly higher incidence and increment of active caries lesions than those without a fixed appliance.

Fluoride varnish for white spot lesion prevention during orthodontic treatment: results of a randomized controlled trial 1 year after debonding

BACKGROUND

Topical fluorides are commonly recommended to prevent the development of white spot lesion (WSL) during treatment with fixed orthodontic appliances (FOAs), but the certainty of evidence is low, and long-term effects of fluoride preventive methods to reduce lesions seem to be rare.

OBJECTIVE

To evaluate the long-term effectiveness of professional applications of a fluoride varnish containing 1.5% ammonium fluoride in preventing WSL development in adolescents undergoing multi-bracket orthodontic treatment.

SUBJECTS AND METHODS

We performed a randomized controlled trial in which 166 healthy adolescents (12-18 years) from three different clinics were enrolled and randomly allocated to a test or a placebo group. The randomization was performed by a computer program, generating sequence numbers in blocks of 15. The fluoride varnish or the non-fluoride placebo varnish was applied in a thin layer around the bracket base every sixth week during the course of the orthodontic treatment (mean duration 1.7 years). We scored the prevalence of WSL on the labial surfaces of the maxillary incisors, canines and premolars immediately after debonding (baseline) and approximately 1 year after debonding, from digital photos with aid of a four-step score. The examiners were not involved in the treatment of the patients and blinded for the group assignment.

RESULTS

One hundred and forty-eight patients were available at debonding and 142 of them could be re-examined after 1 year (71 in the test and 71 in the placebo group). The 1-year attrition rate was 4.0%. On patient level, the prevalence of post-orthodontic WSLs (score ≥ 2) dropped by over 50% during the follow-up with no significant difference between the groups. On surface level, there were significantly fewer remaining WSLs in the test group compared with the placebo group (4.5% versus 10.4%; relative risk 0.44, 95% confidence interval 0.28-0.68).

LIMITATIONS

The compliance with fluoride toothpaste was not checked, and the patients' general dentists may have instigated additional risk-based preventive measures. No cost-benefit analysis was carried out.

CONCLUSIONS

This follow-up study displayed a small beneficial long-term effect of fluoride varnish in reducing WSL development during treatment with FOA.

REGISTRATION

NCT03725020.

PROTOCOL

The protocol was not published before trial commencement.

Microleakage of resin infiltration in artificial white-spot lesions

This study examined the effectiveness of resin infiltration in inhibiting microleakage from artificial white-spot lesions (AWL) in enamel. Fifty sound extracted premolars were selected and randomly divided into five groups (n = 10 each). Group 1 included sound teeth. In contrast, an AWL was created in all specimens in groups 2 to 5, as follows-Group 2: AWL with no treatment; Group 3: AWL treated with resin infiltration; Group 4: AWL treated with resin infiltration and 5,000 cycles of thermocycling; Group 5: AWL treated with resin infiltration and 10,000 cycles of thermocycling. All specimens were then coated with nail varnish, except for a 4 × 4 mm² area on the buccal surface (the measurement area), immersed in 2% methylene blue solution, and sectioned buccolingually. Microleakage was evaluated with a stereomicroscope. Data were analyzed by using the Kruskal-Wallis test and Bonferroni post-hoc correction. Application of resin infiltrant reduced microleakage in AWL. No microleakage was seen in Group 3, and differences between Groups 3, 4, and 5 were not significant (P > 0.05). The resin infiltration technique appears to aid in sealing enamel AWL and may help provide long-term protection against microleakage in enamel AWL.

Effectiveness of self-applied topical fluorides against enamel white spot lesions from multi-bracketed fixed orthodontic treatment: a systematic review

BACKGROUND

The regular use of fluoride dentifrices is quite practical, widespread and linked to global decline of dental caries. However, the role of self-applied topical fluorides in prevention and reversal of Enamel White Spot Lesions (EWSLs) during multi-bracketed fixed orthodontic treatment is not yet explored.

OBJECTIVE

To systematically appraise the current literature on the effectiveness of self-applied topical fluorides in the prevention and reversal of EWSLs occurring during multi-bracketed fixed orthodontic treatment.

SEARCH METHODS

Four electronic databases (Cochrane Library, Embase via Ovid, Medline via Ovid, and Scopus) and gray literature were searched using the broad MeSH terms and keywords.

SELECTION CRITERIA

Only randomized/quasi-randomized controlled clinical trials evaluating the effectiveness of self-applied fluorides in the prevention of EWSLs during multi-bracketed fixed orthodontic treatment or reversal of post-orthodontic EWSLs were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened for studies, extracted data and assessed the risk of bias using the Cochrane risk of bias tool 2.0. Due to substantial variations in the interventions, control groups, and the measurement of outcome among studies, quantitative synthesis could not be performed as planned.

RESULTS

Only three studies could be included in the present review; two of them assessing prevention of EWSLs and one addressing reversal of post-orthodontic EWSLs. One of the studies was judged to be of low risk of overall bias, whereas 2 studies were adjudged to be of high risk of overall bias because of deviations from intended interventions. The certainty of evidence about the role of self-applied fluorides in prevention and reversal of EWSLs was found to be of low quality; hence, our confidence in the effect estimate is limited, and future well-conducted trials might alter the effect estimates.

LIMITATIONS

The inclusion of only English literature and inability to perform quantitative synthesis due to a limited number of studies.

CONCLUSIONS AND IMPLICATIONS

Although the review did not confirm the effectiveness of self-applied fluorides in the reversal of EWSLs, it did partially substantiate the positive role of self-applied fluorides in the prevention of EWSLs occurring during multi-bracketed fixed orthodontic treatment. The review recommends the need for well-designed randomized controlled trials evaluating the effectiveness of self-applied fluorides on the prevention and reversal of EWSLs during multi-bracketed fixed orthodontic treatment.

REGISTRATION

PROSPERO database (Registration number: CRD42018108590) and is freely available at: http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42018108590.

FUNDING

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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.

[Effect of orthodontic traction on the microstructure of dental enamel]

OBJECTIVE

To investigate the effect of orthodontic traction on the microstructure of dental enamel.

METHODS

Forty-eight isolated premolars were randomly divided into 6 groups (n=8), including Group A (blank control group), in which the teeth were bonded with the orthodontic brackets without any loading force; Groups B1, B2, and B3 where the teeth were bonded with the orthodontic brackets using clinical adhesives and loaded with 50 g force for 6 months, 200 g force for 6 months, and 200 g force for 1 month, respectively; and Groups C1 and C2, where the teeth were bonded with straight wire brackets using light curing bonding and chemical curing bonding techniques, respectively. All the teeth were embedded with non-decalcified epoxy resin. Scanning electron microscope (SEM), atomic force microscope (AFM), and energy spectrometer (EDS) were used to analyze interface morphology and elemental composition of the teeth sliced with a hard tissue microtome.

RESULTS

Compared with those in Group A, the teeth in the other 5 groups showed increased adhesive residue index with microcracks and void structures on the enamel surface under SEM; AFM revealed microcracks on the enamel surface with angles to the grinding direction. A larger loading force on the bracket resulted in more microcracks on the enamel interface. The interface roughness differed significantly between Groups A and C2, and the peak-to-valley distance differed significantly between Groups A, C, and C2.

CONCLUSIONS

Orthodontic traction can cause changes in the microstructure of normal dental enamel.

Synergetic Effect of 2-Methacryloyloxyethyl Phosphorylcholine and Mesoporous Bioactive Glass Nanoparticles on Antibacterial and Anti-Demineralisation Properties in Orthodontic Bonding Agents

2-methacryloyloxyethyl phosphorylcholine (MPC) is known to have antibacterial and protein-repellent effects, whereas mesoporous bioactive glass nanoparticles (MBN) are known to have remineralisation effects. We evaluated the antibacterial and remineralisation effects of mixing MPC and MBN at various ratios with orthodontic bonding agents. MPC and MBN were mixed in the following weight percentages in CharmFil-Flow (CF): CF, 3% MPC, 5% MPC, 3% MPC + 3% MBN, and 3% MPC + 5% MBN. As the content of MPC and MBN increased, the mechanical properties of the resin decreased. At 5% MPC, the mechanical properties decreased significantly with respect to CF (shear bond strength), gelation of MPC occurred, and no significant difference was observed in terms of protein adsorption compared to the control group. Composition 3% MPC + 5% MBN exhibited the lowest protein adsorption because the proportion of hydrophobic resin composite decreased; CF (91.8 ± 4.8 μg/mL), 3% MPC (73.9 ± 2.6 μg/mL), 3% MPC + 3% MBN (69.4 ± 3.6 μg/mL), and 3% MPC + 5% MBN (55.9 ± 1.6 μg/mL). In experiments against S. mutans and E. coli, addition of MPC and MBN resulted in significant antibacterial effects. In another experiment, the anti-demineralisation effect was improved when MPC was added, and when MBN was additionally added, it resulted in a synergetic effect. When MPC and MBN were added at an appropriate ratio to the orthodontic bonding agents, the protein-repellent, antibacterial, and anti-demineralisation effects were improved. This combination could thus be an alternative way of treating white spot lesions.

Time-dependent effects after enamel fluoride application on an acid etching system in orthodontic bracket bonding

OBJECTIVES

This study investigated the effectiveness of acid etching and bond strength in an orthodontic bonding system in accordance with various time periods after 1.23% acidulated phosphate fluoride (APF) gel applications.

MATERIALS AND METHODS

APF gel was applied on the enamel surface of bovine teeth, which were assigned to group F0. The tooth specimens were then immersed in distilled water for 1 (F1), 7 (F7), 14 (F14), 21 (F21) and 28 (F28) days. A group without fluoride pretreatment was a control group. All groups were etched with 35% phosphoric acid and evaluated using a surface hardness tester and scanning electron microscope (SEM). A shear bond strength (SBS) test was performed using a universal testing machine, and the bond failure modes were also examined.

RESULTS

After the 1.23% APF gel treatment, the hardness of the acid-etched enamel surface decreased as the immersion period increased. SEM images of the test groups showed etched patterns similar to control group as the immersion period increased. The SBS increased with increasing immersion period, whereas group F21 was not significantly different from the control group. Relatively high adhesive remnant index scores were identified as the ageing period increased.

CONCLUSIONS

The present study indicated that in order to obtain suitable bond strength, it is recommended to use an acid etching-based bonding system for the fixation of orthodontic appliances on the enamel surface 21 days after the use of APF gel.

CLINICAL RELEVANCE

Fluoride pre-treatment interferes with the acid etching effects on enamel, causing a reduction in the bond strength with orthodontic brackets.

Effects of adhesive flash-free brackets on enamel demineralization and periodontal status

OBJECTIVES

To evaluate the effects of adhesive precoated (APC) flash-free brackets on enamel demineralization and periodontal status in patients during fixed orthodontic treatment.

MATERIALS AND METHODS

Thirty patients, age 12 to 18 years, who had Angle Class I or Class II malocclusion with mild to moderate crowding in the permanent dentition were selected for this study. APC flash-free and conventional ceramic brackets were bonded for a split-mouth study design. The quadrant allocation was randomized. Demineralization records were obtained immediately after bonding (T0), 1 month after bonding (T1), and 6 months after bonding (T2). Clinical periodontal measurements, including gingival index, plaque index, and bleeding upon probing, were obtained before bonding (T0) and at the same time points (T1 and T2). Data were analyzed using Mann-Whitney U and Friedman tests to compare parameters between groups and times.

RESULTS

Demineralization values decreased on most sides of the brackets for both groups between T0 and T1. In the conventional group, there was significantly higher demineralization on more sides compared with flash-free brackets between T1 and T2. With one exception, the decreased values were found in the incisal/occlusal sides of all brackets at T2. All periodontal parameters showed significant increases after 6 months of treatment in both groups. Intergroup comparison showed no significant differences in demineralization or periodontal measurements at any of the time points.

CONCLUSIONS

The effects of APC flash-free and conventional brackets on enamel demineralization and periodontal health did not differ from each other.

Physical-chemical interactions between dental materials surface, salivary pellicle and Streptococcus gordonii

Dental materials are susceptible to dental plaque formation, which increases the risk of biofilm-associated oral diseases. Physical-chemical properties of dental material surfaces can affect salivary pellicle formation and bacteria attachment, but relationships between these properties have been understudied. We aimed to assess the effects of surface properties and adsorbed salivary pellicle on Streptococcus gordonii adhesion to traditional dental materials. Adsorption of salivary pellicle from one donor on gold, stainless steel, alumina and zirconia was monitored with a quartz crystal microbalance with dissipation monitoring (QCM-D). Surfaces were characterized by X-ray photoelectron spectroscopy, atomic force microscopy and water contact angles measurement before and after pellicle adsorption. Visualization and quantification of Live/Dead stained bacteria and scanning electron microscopy were used to study S. gordonii attachment to materials with and without pellicle. The work of adhesion between surfaces and bacteria was also determined. Adsorption kinetics and the final thickness of pellicle formed on the four materials were similar. Pellicle deposition on all materials increased surface hydrophilicity, surface energy and work of adhesion with bacteria. Surfaces with pellicle had significantly more attached bacteria than surfaces without pellicle, but the physical-chemical properties of the dental material did not significantly alter bacteria attachment. Our findings suggested that the critical factor increasing S. gordonii attachment was the salivary pellicle formed on dental materials. This is attributed to increased work of adhesion between bacteria and substrates with pellicle. New dental materials should be designed for controlling bacteria attachment by tuning thickness, composition and structure of the adsorbed salivary pellicle.

Demineralization detection in orthodontics using an ophthalmic optical coherence tomography device equipped with a multicolor fluorescence module

OBJECTIVES

Demineralizations such as white spot lesions are among the most prevalent side effects during orthodontic treatment. Fluorescence devices, including quantitative light-induced fluorescence (QLF), exploiting the intrinsic fluorescence of enamel and teeth and most recently optical coherence tomography (OCT) were introduced for early demineralization detection. In addition to near-infrared OCT scanning, multicolor modules allow for imaging with different laser wavelengths and the detection of reflective- and fluorescent light. The aim of this study was to evaluate a modified multicolor ophthalmic OCT device for the detection of early carious lesions in vitro and in vivo.

MATERIALS AND METHODS

Twenty-seven extracted lesion free human teeth were randomly assigned to three different demineralization protocols. Carious lesion detection was performed using macrophotography, OCT, and reflectance/fluorescence imaging using green laser and blue laser light. In addition, teeth of 5 orthodontic patients were OCT scanned, and fluorescence imaging using blue laser light was performed to assess demineralization after orthodontic therapy.

RESULTS

Both in vitro and in vivo, OCT allowed for precise determination of lesion depth and enamel loss. Fluorescence imaging using blue laser light was most sensitive for the detection of early demineralization in vitro and in vivo. However, established and severe demineralizations were also reliably detected by macrophotography in vitro and in vivo.

CONCLUSION

Demineralization can be detected with high sensitivity using blue fluorescence imaging with multicolor OCT devices.

CLINICAL RELEVANCE

In the future, OCT fluorescence imaging might be considered for longitudinal monitoring of dental hard tissue during orthodontic treatment in clinical trials.