Effects of chlorhexidine varnish on caries during orthodontic treatment: a systematic review and meta-analysis

Prevention of demineralization during multi-bracketed fixed orthodontic treatment: An overview of systematic reviews

BACKGROUND

Demineralization during multi-bracketed fixed orthodontic treatment is a well-known problem.

AIM

To systematically evaluate the evidence for the prevention of enamel demineralization during multi-bracketed fixed orthodontic treatment.

DESIGN

Systematic reviews (with or without meta-analysis) that have appraised the primary studies on the prevention of demineralization during multi-bracketed fixed orthodontic treatment were searched systematically and included as per pre-defined eligibility criteria. The risk of bias of the included reviews was assessed by two authors using the ROBIS tool and AMSTAR-2 tool.

RESULTS

Twenty-nine reviews conducted on 128 exclusive primary studies were included for the present overview; 23 of these reviews were assessed to be of a high risk of overall bias, 5 were of low risk, and 1 review was of unclear risk of bias.

CONCLUSIONS

Predominantly, the published reviews have focused on fluorides, whereas some reviews have also studied the role of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), reminder therapy, lasers, and sealants. Professional fluorides, sealants, reminder therapy, and lasers might be valuable interventions to prevent demineralization during orthodontic treatment based on the conclusions of reviews with high quality; however, further studies are required to elucidate the role of CPP-ACP, chlorhexidine varnish, and powered toothbrushes.

A Comparison of the Adaptive Response of Staphylococcus aureus vs. Streptococcus mutans and the Development of Chlorhexidine Resistance

Antimicrobials with nonselective antibacterial efficacy such as chlorhexidine can be effective in reducing biofilm, but bear the risk of inducing resistance in specific bacteria. In clinical practice, bacteria such as Staphylococcus aureus have been found resistant to chlorhexidine, but other bacteria, including Streptococcus mutans, have largely remained susceptible to chlorhexidine despite its widespread use in oral healthcare. Here, we aim to forward a possible reason as to why S. aureus can acquire resistance against chlorhexidine, while S. mutans remains susceptible to chlorhexidine. Measurement of surface-enhanced fluorescence indicated that chlorhexidine caused gradual, but irreversible deformation to adhering green fluorescent S. aureus due to irreparable damage to the cell wall. Concurrently, the metabolic activity of adhering staphylococci was higher than of planktonic bacteria, suggesting efflux mechanisms may have been activated upon cell wall deformation, impeding the buildup of a high chlorhexidine concentration in the cytoplasm and therewith stimulating the development of chlorhexidine resistance in S. aureus. Exposure of S. mutans to chlorhexidine caused immediate, but reversible deformation in adhering streptococci, indicative of rapid self-repair of cell wall damage done by chlorhexidine. Due to cell wall self-repair, S. mutans will be unable to effectively reduce the chlorhexidine concentration in the cytoplasm causing solidification of the cytoplasm. In line, no increased metabolic activity was observed in S. mutans during exposure to chlorhexidine. Therewith, self-repair is suicidal and prevents the development of a chlorhexidine-resistant progeny in S. mutans.

What Are the Cleaning and Disinfection Methods for Acrylic Orthodontic Removable Appliance? A Systematic Review

(1) Background: The use of removable orthodontic appliances, which is common in early ages, requires careful hygiene, as several different microorganisms are found on their surface during the orthodontic treatment. (2) Methods: Comprehensive electronic searches were conducted up to May 2021. Randomized controlled trials (RCTs) or controlled clinical trials (CCTs), prospective or retrospective, evaluating the efficacy of cleaning and disinfection methods for acrylic removable orthodontic appliances, redacted in the English language, were included. Three independent blinding review authors were involved in study selection, data extraction, and bias assessment. (3) Results: A total of 2491 records were screened and eight studies (six RCTs and two CCTs) fulfilled the inclusion criteria. Among the overall cleaning and disinfection methods described in the included studies, four categories could be defined: liquid antimicrobial agents, commercial tablet cleansers, natural plant extracts and incorporation of quaternary ammonium methacryloxy silicate, all of which demonstrated superior efficacy compared to the placebo/negative control. However, the different methods were not compared with each other. (4) Conclusions: Biofilm control on acrylic orthodontic removable appliances can be performed using the different cleaning and disinfection methods considered in the included studies. Further studies are needed to define the most effective technique. Registration: PROSPERO CRD 42021269297.

Biofilm formation following chitosan-based varnish or chlorhexidine-fluoride varnish application in patients undergoing fixed orthodontic treatment: a double blinded randomised controlled trial

Background

Orthodontic treatment poses an increased risk of plaque accumulation and demineralisation of enamel leading to white spot lesion around the brackets. This parallel arm trial aims to assess the degree of bacterial plaque formation adjacent to orthodontic brackets, following the application of a chitosan-based varnish or chlorhexidene-fluoride varnish.

Methods

A total of 200 teeth from 20 patients undergoing fixed orthodontic therapy were assessed and biofilm formation around the brackets were recorded using the Bonded Bracket Index (Plaque index) at baseline and weekly for 6 weeks. The bacterial count and plaque pH at corresponding weekly intervals were also recorded. Following bracket bonding, the patients were cluster randomised to receive chitosan-based varnish-CHS (UNO Gel Bioschell, Germiphene corp., Brantford, Canada) or chlorhexidine-fluoride varnish-CFV (Cervitec F, Ivoclar Vivadent, Schaan, Liechtenstein) every week on the representative teeth respectively. BBI proportions were compared between groups at all time intervals using Chi square test. Mean plaque bacterial count and plaque pH were compared using Mann Whitney U test and Tukey’s HSD test respectively.

Results

Baseline characteristics were similar between the groups: Mean age was CHS = 23 and CFV = 21; male to female ratio was CHS = 5/5, CFV = 7/3. At the end of 6 weeks, chitosan-based varnish performed equal to chlorhexidine-fluoride varnish (P > 0.05) with 98% and 95% of teeth with acceptable scores respectively. The plaque bacterial count significantly reduced at 6 weeks for both varnish compared to the baseline; The value for CHS was 0.43 ± 0.4 × 10⁴ and CFV was 0.77 ± 0.64 × 10⁴ CFU (P < 0.05), with no difference between both the varnishes. Both varnishes had no effect on the plaque pH that remained neutral.

Conclusion

This trial showed that both chitosan-based varnish and chlorhexidine-fluoride varnish reduced bacterial count, while the plaque pH remained neutral over a period of six weeks in patients undergoing fixed orthodontic therapy. The anti-plaque effects of the natural biopolymeric chitosan-based varnish was similar to that of chlorhexidine-fluoride varnish, a known chemotherapeutic agent.

Registration: This trial protocol was registered with https://www.ctri.nic.in (CTRI/2019/05/018896). (Date of registration 02/05/2019).

Protocol: The protocol was not published before trial commencement.

Effect of Cavity Disinfectants on Dentin Bond Strength and Clinical Success of Composite Restorations-A Systematic Review of In Vitro, In Situ and Clinical Studies

Cavity disinfection becomes an important step before a dental restorative procedure. The disinfection can be obtained cleaning the dental cavity with antimicrobial agents before the use of adhesive systems. The aim of this study was to conduct a systematic review on the effect of different cavity disinfectants on restorations’ adhesion and clinical success. A search was carried out through the Cochrane Library, PubMed, and Web of Science. In vitro and in situ studies reporting results on dentin bond strength tests, and clinical studies published until August 2020, in English, Spanish and Portuguese were included. The methodological quality assessment of the clinical studies was carried out using the Revised Cochrane risk-of-bias tool. Chlorhexidine could preserve adhesion to dentin. EDTA and ethanol had positive results that should be further confirmed. Given the significant lack of scientific evidence, the use of lasers, fluoridated agents, sodium hypochlorite, or other products as cavity disinfectants should be avoided. Chlorhexidine is a safe option for cavity disinfection with adequate preservation of adhesion to dentin. Moreover, future researches should be focused on the efficacy of these disinfectants against cariogenic bacteria and their best application methods.

Effect of Chlorhexidine and Fluoride Varnishes on Streptococcus mutans Count and Dental Plaque Index

AbstractThe control of dental plaque by chemical means can be a valuable auxiliary resource for individuals who have difficulties in performing dental plaque control through regular oral hygiene procedures. The aim of this study was to evaluate the effect of chlorhexidine and fluorine varnishes on the levels of Streptococcus mutans (S. mutans) present in the dental biofilm and on the dental plaque index. The study was carried out in a sample comprised thirty-nine schoolchildren between 13 and 15 years of age, distributed into 2 groups. Group I received a single layer of varnish with chlorhexidine and thymol on the maxillary right first molar. Group II received the application of varnish with fluoride following the same methodology. S. mutans count and dental plaque index recording were performed 7 days before the application and 7, 15 and 30 days after the treatment. It was observed that chlorhexidine and fluoride varnishes significantly reduced the number of S. mutans in dental plaque for 30 days (p<0.05). There was no difference between the varnishes. With regard to the dental plaque index, there was no alteration in any of the experimental time periods for both groups. It was concluded that varnishes, mainly those that contain fluoride, can be an interesting alternative for the prevention of dental caries in collective oral health programs. Keywords: Chlorhexidine. Fluorides. Dental Plaque. ResumoO controle da placa dental por meios químicos pode ser um valioso recurso auxiliar para indivíduos que apresentam dificuldades em realizar o controle da placa dental por meio de procedimentos regulares de higiene bucal. O objetivo neste estudo foi avaliar o efeito dos vernizes de clorexidina e de flúor sobre os níveis de Streptococcus mutans (S. mutans) presentes no biofilme dental e sobre o índice de placa dental. O estudo foi realizado em uma amostra composta por 39 escolares, entre 13 e 15 anos de idade, distribuídos em 2 grupos. O grupo I recebeu uma única aplicação de verniz com clorexidina e timol no primeiro molar superior direito. O grupo II recebeu a aplicação de verniz com flúor seguindo a mesma metodologia. A contagem de S. mutans e o índice de placa dental foram registrados 7 dias antes da aplicação e 7, 15 e 30 dias após o tratamento. Observou-se que os vernizes de clorexidina e flúor reduziram significativamente o número de S. mutans na placa dental por 30 dias (p <0,05). Não houve diferença entre os vernizes. Com relação ao índice de placa dental, não houve alteração em nenhum dos períodos experimentais para ambos os grupos. Concluiu-se que os vernizes, principalmente aqueles que contêm flúor, podem ser uma alternativa interessante para a prevenção da cárie dentária em programas coletivos de saúde bucal. Palavras-chave: Clorexidina. Fluoretos. Placa Dentária.

Systematic reviews in orthodontics: Impact of the PRISMA for Abstracts checklist on completeness of reporting

INTRODUCTION

This study evaluated and compared the completeness of reporting of abstracts of orthodontics systematic reviews before and after the publication of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Abstracts Checklist (PRISMA-A).

METHODS

Abstracts of systematic reviews and meta-analyses in orthodontics published in PubMed, Latin American and Caribbean Health Sciences Literature, and the Cochrane Database of Systematic Reviews databases before March 23, 2018, that met the predefined inclusion and exclusion criteria, were evaluated using the 12 items of PRISMA-A, scoring each item from 0 to 2. Abstracts were classified into 2 groups: before and after publication of the PRISMA-A checklist. Three calibrated evaluators (intraclass correlation coefficient and kappa > 0.8) assessed the scores for compliance with the checklist. The number of authors, country of affiliation of the first author, performance of meta-analysis, and topic of the article were recorded. A regression analysis was performed to assess the associations between abstract characteristics and the PRISMA-A scores.

RESULTS

Of 1034 abstracts evaluated, 389 were included in the analysis. The mean PRISMA-A score was 53.39 (95% CI, 51.83-54.96). The overall score for studies published after the publication of the checklist was significantly higher than for studies published before (P ≤ 0.0001). The components returning significantly higher scores after publication of PRISMA-A were title (P = 0.024), information from databases (P = 0.026), risk of bias (P ≤ 0.0001), included studies (P ≤ 0.0001), synthesis of results (P ≤ 0.0001), interpretation of results (P = 0.035), financing and conflict of interest (P ≤ 0.0001), and registration (P ≤ 0.0001). These results showed the positive effect of PRISMA-A had on the quality of reporting of orthodontics systematic reviews. Nevertheless, the poor adherence revealed that there is still need for improvement in the quality of abstract reporting.

CONCLUSIONS

The quality of reporting of abstracts of orthodontic systematic reviews and meta-analyses increased after the introduction of PRISMA-A.

Surface morphologic evaluation of orthodontic bonding systems under conditions of cariogenic challenge

Orthodontic bonding systems are submitted to demineralization and remineralization dynamics that might compromise their surface smoothness, and favor biofilm aggregation and caries development. The aim of the present study was to evaluate the effects of a cariogenic challenge model (in vitro pH-cycling model) on the surface roughness and topography of 3 bonding materials: Transbond™ XT (XT), Transbond™ Plus Color Change (PLUS) and Fuji Ortho™ LC (FUJI), by means of Atomic Force Microscopy (AFM). Six specimens with standardized dimensions and surface smoothness were fabricated per group, and the materials were manipulated in accordance with the manufacturers' instructions. No polishing was necessary. AFM tests were performed before and after pH-cycling, taking 3 readouts per specimen. The roughness results (Ra) were obtained at nanometric levels (nm) and surface records were acquired in two- and three-dimensional images of height and lock-in phase of the material components. The surfaces of all groups analyzed in the study were morphologically altered, presenting images suggestive of matrix degradation and loss of matrix-load integrity. FUJI presented the greatest increase in surface roughness, followed by XT and PLUS, respectively (p≤0.001). Nevertheless, the roughness values found did not present sufficient degradation to harbor bacteria. The surface roughness of all tested materials was increased by pH-cycling. The use of materials capable of resisting degradation in the oral environment is recommended, in order to conserve their integrity and of the surrounding tissues.

Efficacy of palifermin on oral mucositis and acute GVHD after hematopoietic stem cell transplantation (HSCT) in hematology malignancy patients: a meta-analysis of trials

Aim of the study

Herein, this meta-analysis study evaluated the efficacy of palifermin after HSCT on the incidence and severity of OM or aGVHD in hematologic malignancy patients in randomized clinical trials (RCTs).

Materials and methods

To compare the efficacy of palifermin on adverse events, OM and aGVHD compared with placebo, we searched databases of PubMed/Medline, Web of Science and Cochrane Library for RCTs based on a number of criteria.

Results

There was no difference observed in the incidence of OM and aGVHD between two groups. The subgroup analysis didn’t show significant differences in two groups for aGVHD grade 2–4 (odds ratio [OR] = 1.54, 95% confidence interval (CI): 0.70–3.39, p = 0.28), aGVHD grade 3–4 (OR = 0.97, 95% CI: 0.48–1.94, p = 0.92), OM grade 2–4 (OR = 0.76, 95% CI: 0.42–1.38, p = 0.37) and OM grade 3–4 (OR = 0.54, 95% CI: 0.25–1.15, p = 0.11], but erythema as an adverse effect in palifermin group was higher than placebo group (OR = 1.86, 95% CI: 1.10–3.15, p = 0.02].

Conclusions

This meta-analysis of six clinical trials found no statistically significant difference in OM and aGVHD grades in patients receiving 60 μg/kg/day dose of palifermin compared with those receiving a placebo. However, oral mucosal erythema was more prevalent among patients receiving palifermin than patients receiving a placebo.