Clinical and microbiologic evaluation of a resin modified glass ionomer cement for orthodontic bonding

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

BACKGROUND

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

OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Modification of resin modified glass ionomer cement by addition of bioactive glass nanoparticles

In the present study, sol-gel derived nanoparticle calcium silicate bioactive glass was added to the resin-modified light cure glass-ionomer cement to assess the influence of additional bioactive glass nanoparticles on the mechanical and biological properties of resin-modified glass-ionomer cement. The fabricated bioactive glass nanoparticles added resin-modified glass-ionomer cements (GICs) were immersed in the phosphate buffer solution for 28 days to mimic real condition for the mechanical properties. Resin-modified GICs containing 3, 5 and 10 % bioactive glass nanoparticles improved the flexural strength compared to the resin-modified glass-ionomer cement and the samples containing 15 and 20 % bioactive glass nanoparticles before and after immersing in the phosphate buffer solution. Characterization of the samples successfully expressed the cause of the critical condition for mechanical properties. Cell study clarified that resin-modified glass-ionomer cement with high concentrations of bioactive glass nanoparticles has higher cell viability and better cell morphology compare to control groups. The results for mechanical properties and toxicity approved that the considering in selection of an optimum condition would have been a more satisfying conclusion for this study.

A randomized clinical trial comparing ‘one-step’ and ‘two-step’ orthodontic bonding systems

OBJECTIVE

The primary objective of this prospective clinical trial was to assess the clinical bond failure rates of orthodontic brackets bonded using a self-etching primer (SEP), compared with brackets bonded using a conventional acid-etched technique with control adhesive (Transbond). A secondary aim was to investigate whether characteristics of the operator, patient or tooth bonded had any influence on bracket failure.

DESIGN

Single-centre randomized controlled clinical trial. Thirty-four patients were bonded, each being randomly assigned to either the test or control adhesive.

SETTING

NHS Hospital Orthodontic Department, Chester, UK.

SUBJECTS

Orthodontic patients requiring fixed appliance treatment.

MAIN OUTCOME MEASURES

Bond failure.

MAIN OUTCOME RESULTS

Failure rates over the initial 6-month period were 2.0% (Transbond) and 1.7% (SEP) with no statistically significant difference between the two groups. Over the duration of the fixed appliance treatment, bond failure rates increased, but remained acceptable at 7.4 % (TB) and 7.0% (SEP), respectively. When operator, patient and tooth characteristics were analysed, only the bracket location was found to be significant. Maxillary brackets were more likely to fail than mandibular brackets (RR 0.47%; 95% CI 0.22, 1.03). The failure rate for brackets in our study was low when compared with previous studies.

CONCLUSIONS

Both the acid-etched control and self-etching primer in combination with adhesive pre-coated brackets were successful for clinical bonding. Their combined failure rate was lower than that reported in similar trials.

Retention of orthodontic brackets bonded with resin-modified GIC versus composite resin adhesives--a quantitative systematic review of clinical trials

The aim of this systematic review was to establish whether the clinical debonding (failure) rates of orthodontic brackets bonded either with resin-modified glass ionomer (RM-GIC) or with composite resin adhesive are the same. Five databases were searched for articles up to 18 November 2010. Inclusion criteria were titles/abstracts relevant to the review question and two or more arm clinical trial. Exclusion criteria were the following: no computable data recorded and subjects of both groups not followed up in the same way. From the accepted trials, datasets were analysed concerning clinical precision and internal validity. Eleven trials were accepted. From these, 15 dichotomous datasets were extracted. Relative risk with 95% confidence interval of nine datasets showed no statistically significant differences in outcome between the treatment and control group after 6 months-1.32 years. Five showed a statistically significant difference (p < 0.05), favouring resin composite bonding after 12 and 18 months. One favoured RM-GIC after 10 months. Meta-analysis found no difference in the failure rate between the two treatment groups after 12 months (RR, 1.11; 95% CI, 0.87-1.42; p = 0.40) and found in favour of composite resin adhesive after >14 months (RR, 2.25; 95% CI, 1.60-3.17; p < 0.00001). All trials had poor internal validity due to selection and detection/performance bias risk. The current evidence suggests no difference between the types of materials after 12 months but favours composite resin adhesives after a >14-month period. However, its risk of selection and detection/performance bias are high, and all results need to be regarded with caution. Further high quality randomised control trials addressing this topic are needed. The clinical relevance of this study is that RM-GIC may have the same clinical debonding (failure) rate as composite resin adhesives after 1 year when used for bonding of orthodontic brackets.

[Methods of bonding to the enamel in orthodontics]

Mastery of the bonding stage of treatment is clearly a critical step in the clinical practice of orthodontics. There is such a wide variety of products available in orthodontics that a reasoned assessment of bonding systems is a practical necessity. Composite plastics, associated with hydrophobic or hydro-compatible adhesive systems, and the CVIMAR represent the two principal types of bonding agents used in dentistry. They are categorized according to their constituents into a wide range of products whose nuanced differences are sometimes difficult to discern. This paper first focuses on the development of the composition of the various materials, a depiction of the fundamental parameters of adhesion, and a detailed terminology to help the reader reach a basic understanding. Bonding systems are designed to fulfill the requirements of specific clinical situations. A description of their modes of adhesion, of their composition, and of their advantages and disadvantages will be presented in the second part of this article.

[Comparison of 1-stage orthodontic bonding systems and 2-stage bonding systems: a review of the literature and the results of a randomized clinical trial]

OBJECTIVE

The main objectives of this study are to present a literature review of self-etching primer's (SEP's) and present the outcomes of a prospective clinical trial to assess the clinical bond failure rates of orthodontic brackets bonded using a self-etching primer (SEP), compared with brackets bonded using a conventional acid-etched technique with a control adhesive (Transbond). A secondary aim was to investigate whether characteristics of the operator, patient or tooth bonded had any influence on bracket failure.

DESIGN

Single-centre randomized controlled clinical trial. Thirty-four patients were bonded, each being randomly assigned to either the test or control adhesive.

SETTING

Orthodontic Department Countess of Chester Hospital, Chester, UK.

SUBJECTS

Orthodontic patients requiring fixed appliance treatment.

MAIN OUTCOME MEASURES

Bond failure.

MAIN OUTCOME RESULTS

Failure rates over the initial 6-month period were 2.0% (Transbond) and 1.7% (SEP) with no statistically significant difference between the two groups. Over the duration of the fixed appliance treatment, bond failure rates increased, but remained acceptable at 7.4% (TB) and 7.0% (SEP), respectively. When operator, patient and tooth characteristics were analysed, only the bracket location was found to be significant. Maxillary brackets were more likely to fail than mandibular brackets (relative risk 0.47%; 95% confidence interval 0.22, 1.03). The failure rate for brackets in our study was low when compared with previous studies.

CONCLUSIONS

Both the acid-etched control and self-etching primer in combination with adhesive pre-coated brackets were successful for clinical bonding. Their combined failure rate was lower than that reported in similar trials. The literature on SEP's supports the findings of this study.

Fluoride-containing restorative materials

Dental practitioners are exposed to an increasing number of dental materials, which claim the benefits of fluoride release. The purpose of this paper is to critically review the literature of these materials. Glass ionomers, resin modified glass ionomers, compomers, resin composites, fissure sealants and amalgam are discussed. It is clear that a long-term measurable release of fluoride can be observed from certain restorative materials, in vitro, particularly glass ionomer cement, resin modified glass ionomer cement, fluoridated cements, fluoridated dental amalgam and certain fissure sealants. In general, the rate of fluoride release is not constant but exhibits a relatively rapid initial rate, which decreases with time. However, the fluoride release profiles may be dependent on specific formulation and on experimental design and sampling methods. These materials may feature greater longevity, a reduced incidence of marginal failure, an elevated concentration of fluoride in contingent plaque, together with an antibacterial action when compared with non-fluoride releasing materials. In addition, fluoride-releasing materials may perform better in caries inhibition in artificial caries model studies than non-fluoridated materials. While any, or all, of these anti-cariogenic effects may be associated with fluoride release, a direct relationship between fluoride release profiles and such effects has not been determined in vivo.

Fluorides for the prevention of white spots on teeth during fixed brace treatment

BACKGROUND

White spots can appear on teeth during fixed brace treatment because of early decay around the brace attachments. Fluoride is effective at reducing decay in susceptible individuals and is routinely prescribed in various different forms to patients during orthodontic treatment.

OBJECTIVES

To evaluate the effectiveness of fluoride in preventing white spots during orthodontic treatment and to compare the different modes of delivery of fluoride.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group's Trials Register (to 22 August 2002); CENTRAL (The Cochrane Library Issue 3, 2002); MEDLINE (January 1966 to July 2003); EMBASE (January 1980 to week July 2003). Authors of trials were contacted for further data.

SELECTION CRITERIA

Trials were selected if they met the following criteria: a randomised or quasi-randomised clinical trial, involving the use of a fluoride-containing product compared with no use or use of a non-fluoride control and enamel demineralisation was assessed during or after orthodontic treatment.

DATA COLLECTION AND ANALYSIS

Six reviewers independently, in duplicate, extracted data. The primary outcome was the difference in the presence or absence of white spots between experimental and control patients for parallel design studies, and between experimental and control quadrants, for split-mouth design studies. Potential sources of heterogeneity were examined. Sensitivity analyses were undertaken for the items assessed for quality and publication bias.

MAIN RESULTS

The primary outcome of the review was the presence or absence of white spots by patient at the end of treatment. Secondary outcomes included any quantitative assessment of enamel mineral loss or lesion depth. Other outcomes such as differences in size and severity of white spots, any patient based outcomes, such as perception of white spots could not be included because there were insufficient data. Fifteen trials, with 723 participants, provided data for this review. None of the studies fulfilled all of the methodological quality assessment criteria. There is some evidence that a daily sodium fluoride mouthrinse reduces the severity of enamel decay surrounding a fixed brace (weighted mean difference for lesion depth -70.0; 95% CI -118.2 to -21.8) and that use of a glass ionomer cement for bracket bonding reduces the prevalence (Peto OR 0.35; 95% CI 0.15 to 0.84) and severity of white spots (weighted mean difference for mineral loss -645 vol%.microm; 95% CI -915 to -375) compared with composite resins.

REVIEWERS' CONCLUSIONS

There is some evidence that the use of topical fluoride or fluoride-containing bonding materials during orthodontic treatment reduces the occurrence and severity of white spot lesions, however there is little evidence as to which method or combination of methods to deliver the fluoride is the most effective. Based on current best practice in other areas of dentistry, for which there is evidence, we recommend that patients with fixed braces rinse daily with a 0.05% sodium fluoride mouthrinse. More high quality, clinical research is required into the different modes of delivering fluoride to the orthodontic patient.

An evaluation of the cytotoxic effects of orthodontic bonding adhesives upon a primary human oral gingival fibroblast culture and a permanent, human oral cancer-cell line

The purpose of this investigation was to determine the cytotoxic effects of three different kinds of orthodontic adhesive on a human primary gingival fibroblast culture (GF) and a human oral cancer-cell line (OC2). The adhesives comprised a self-cure bonding resin, a light-cure bonding resin, and a hybrid glass ionomer. Any differences between the cytotoxic potencies of eluates of the orthodontic materials on GF and OC2 cells were quantified colorimetrically (MTT test). The results are as follows: For the hybrid glass ionomer, the survival rate of GF cells exposed to the liquid component revealed a significant dose-dependent decrease (p < 0.05). The liquid component and the mixed hybrid glass-ionomer material reflected a significant dose-dependent decrease (p < 0.05) in exposed OC2 cell survival. Associated with an increase in the cell exposure concentration of Resin A, Resin B, Paste A, Paste B, Resin A + B, Paste A + B and the set material of the self-cure resin adhesive, was a significant decrease in survival rate for cultured GF and OC2 cells (p < 0.05). Associated with an increase in the concentration of the primer, paste, and mixed material of the light-cure resin adhesive to which test cells were exposed, the survival rate reflected a decrease for GF cells (p < 0.05). The survival rate of cells exposed to light-cure resin paste reflected no difference for OC2 cells. It is concluded that the liquid of the hybrid glass-ionomer cement, Resin A and Resin B and Resin A + B of the self-cure resin and the primer of the light-cure resin are toxic agents to the GF and OC2 cell lines. Primary human gingival fibroblasts were found to be more sensitive than the tested human oral carcinoma cell line from most of the substances.

An 18-month clinical study of bond failures with resin-modified glass ionomer cement in orthodontic practice

The purpose of this study was to evaluate, over an 18-month period, the clinical performances of a resin-modified glass ionomer cement for bonding orthodontic brackets and to analyze various factors that influenced their survival and failure rates. Two orthodontists using the edgewise technique participated in this study; 6113 brackets, including 20 molar tubes, were bonded with Fuji Ortho LC (GC, Europe, N.V. Leuven, Belgium) in 135 patients. Ceramic, metal, and resin brackets were tested, and both operators used the same bonding method for the brackets. The survival rate and the failure rate of the brackets were evaluated. The rates were determined by operator, bracket type, tooth position in the dental arch, and age and sex of the patients. Bracket survival rates were estimated using the Kaplan-Meier test. The Cox-Mantel statistical test with a level of significance set at 0.05 was used to compare survival curves. The chi-square test was used at a level of P < .05 to compare failure rates. The overall failure rate for the sample was 7%, and the overall survival rate was equal to 0.918. Age had no significant influence on the failure rate (P = .07); however, it had a significant influence on the survival rate (P < .01). The best survival rates were obtained in the groups aged 16 to 20 years (S[t] = 0.943) and older than 20 years (S[t] = 0.929). The difference between males and females was not statistically significant in terms of failure rate (P = .17). However, the Cox-Mantel test showed a higher bracket survival rate for the males (S[t] = 0.924) than for the females (S[t] = 0.839) (P < .00001). The influence of the operator was not statistically significant on the failure rate (P = .08); however, it was significant on the survival rate (P < .0002). Location in the arch had a significant influence on the failure and survival rates. The worst results were obtained in the upper incisors and the canines, and the best results in the lower premolars. Fifteen percent of the molar tubes failed; their survival rate was equal to 0.833. The failure rate was significantly greater for resin brackets than for metal or ceramic brackets (P = .007). The highest survival rate was obtained with ceramic brackets (P = .0001). This in vivo study showed that bonding brackets and molar tubes with Fuji Ortho LC is compatible with clinical orthodontic practice.

The effect of long-term water storage on the tensile strength of orthodontic brackets bonded with resin-reinforced glass-ionomer cements

The purpose of this study was to evaluate in vitro the effect of water storage on the tensile bond strength of orthodontic brackets bonded with Vitremer and Fuji II LC resin-reinforced glass-ionomer cements. Seventy-two extracted human premolars were randomly divided into 6 groups and the bonding strengths of the resin-reinforced glass-ionomer cements were compared to control groups bonded with Concise composite resin at 24 hours and 9 months. The brackets were bonded on prepared teeth and a tensile load was applied to dislodge the brackets held in a special device from Lloyd 1000R testing machine. The effects of duration of water exposure, type of bonding material and interaction between long-term water exposure and type of bonding material on the bonding strength were described using the Weibull regression model. The mean tensile bond strength of resin-reinforced glass-ionomers after 24 hours water storage was significantly lower than the mean of the control samples. The results of this study showed no effect of water exposure on the tensile bond strength of brackets bonded with Vitremer glass-ionomer cement. The mean bonding strength of brackets bonded with Fuji II LC without enamel pre-conditioning significantly increased after 9-months water storage as compared to Fuji samples exposed to water for 24 hours. The results of this investigation allow to conclude: 1. Long-term water storage had not decreased the bond strength of resin-reinforced glass-ionomers applied as orthodontic adhesives, 2. Weibull regression model is an adequate and flexible tool to evaluate the bonding properties of dental materials.

Shear bond strengths of two resin-modified glass ionomer cements to porcelain

Shear bond strength of a composite resin adhesive (Concise) and two resin-modified glass ionomer cements (Fuji Ortho LC and Geristore) bonded to porcelain surface was tested. Orthodontic brackets were bonded to 120 porcelain disks (Finesse) etched with 9% HF. Samples were divided into six groups: (1) Concise, (2) Concise/silane, (3) Geristore, (4) Geristore/silane, (5) Fuji, (6) Fuji/silane. No statistical difference in mean shear bond strength was found between silanated Concise (15.8 MPa), Geristore (19.4 MPa), and Fuji (18.5 MPa) groups, which were significantly higher than nonsilanated groups. Porcelain fracture was observed in all silanated groups and nonsilanated Geristore group. We conclude that (1) silane increases bond strength to porcelain significantly for composite resin and resin-modified glass ionomer cement, (2) Concise, Geristore, and Fuji Ortho LC provide comparable shear bond strength to porcelain.

Shear bond strength of a resin-reinforced glass ionomer cement: an in vitro comparative study

Shear bond strength of Concise (a composite resin adhesive) and Fuji Ortho LC (a light-cured resin-reinforced glass ionomer cement) bonded to extracted teeth was tested under different bonding conditions: (1) Concise/etched/dry (2) Fuji/etched/dry (3) Fuji/etched/wet (4) Fuji/unetched/dry (5) Fuji/unetched/wet. Concise/etched/dry and Fuji/etched/dry groups showed comparable mean shear bond strength (10.5 and 8.2 MPa, respectively); the other three groups had considerably lower values. The difference between Fuji/etched/dry and Fuji/etched/wet was not statistically significant. The site of bond failure was between bracket and adhesive in all etched groups and between adhesive and enamel in the unetched groups. We conclude that (1) enamel surface etching is required for Fuji Ortho LC to achieve optimum bond strength, (2) moisture does not affect bond strength of Fuji Ortho LC significantly.

Dental materials: 1996 literature review. Part 2

This critical review of the published literature on dental materials for the year 1996 has been compiled by the Dental Materials Panel of the UK. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, resin-bonded bridges and ceramo-metallic restorations, ceramics, denture base resins and soft lining materials, impression materials, implants materials, orthodontic materials, biomechanics and image processing, resin composites and casting investment materials and waxes). Three hundred and thirteen articles have been reviewed.