Do HEMA-free adhesive systems have better clinical performance than HEMA-containing systems in noncarious cervical lesions? A systematic review and meta-analysis

Abstract

Objectives

To determine through a systematic review whether HEMA-free adhesive systems have better clinical performance than HEMA-containing systems in noncarious cervical lesion (NCCL) restorations.

Sources

We systematically searched PubMed, The Cochrane Library, Scopus, Web of Science, and Open Grey databases using MeSH terms, synonyms, and keywords, with no language or date restriction. The reference lists of included articles were manually searched.

Study selection

Randomized controlled clinical trials comparing the effectiveness of HEMA-free and HEMA-containing adhesive systems in NCCL restorations were included. The risk of bias in the included studies was assessed and classified through the Cochrane Collaboration’s common scheme for bias. Quantitative data were subgrouped according to the main clinical parameters evaluated, and heterogeneity was tested using I 2 index.

Data

A total of 2889 potentially relevant studies were identified. After title and abstract examination, 51 studies remained. Finally, 22 studies were included in the systematic review, totaling to 997 participants. Thus, 13 studies were classified as “low” risk of bias and nine as “unclear”. These 22 studies were also included in the meta-analysis, and no significant statistical difference was found between the clinical performances of HEMA-free and HEMA-containing adhesive systems for all parameters analyzed: retention risk difference (RD) 0.03 [−0.01, 0.07] (p = 0.13); marginal discoloration RD 0.02 [−0.01, 0.04] (p = 0.19); marginal adaptation RD −0.01 [−0.04, 0.01] (p = 0.34); caries RD 0.00 [−0.01, 0.01] (p = 0.92); or postoperative sensitivity RD −0.00 [−0.02, 0.01] (p = 0.72) and for overall effect RD 0.00 [−0.01, 0.01] (p = 0.65).

Conclusions

HEMA-free and HEMA-containing adhesive systems showed a similar clinical performance in NCCL restorations.

Clinical significance

Only the presence of HEMA does not indicate better clinical performance of adhesive systems.

Introduction

Owing to the large number of dental adhesive systems on the market, it is a challenge to select the better ones. Moreover, some of these adhesive materials are developed or introduced as modified versions onto the market without clinical validation .

It is important to emphasize that there are several components that play important functions in the adhesive performance; however, 2-hydroxyethyl methacrylate (HEMA) seems to be the most commonly used, and it is an important chemical component . This monomer was introduced in the adhesive composition during the 1970s with the aim of improving the wettability and diffusion into the demineralized collagen fibrils because of its high hydrophilicity . However, some long-term disadvantages have been reported, particularly with regard to its high hydrophilicity over time. The increased water uptake results in hydrolytic degradation of the adhesive interface .

For this reason, manufacturers launched adhesive systems without this monomer, the so-called HEMA-free adhesives, into the market to avoid its negative effects . Since then, several studies have been carried out to evaluate the clinical performance of these adhesive systems. The influence of HEMA on the clinical performance of composite restorations remains controversial. Some studies have shown no significant differences between the clinical performances of HEMA-free and HEMA-containing adhesive systems. However, other studies revealed different clinical performances between these two adhesive systems (HEMA-free and HEMA-containing adhesive systems).

To assess the clinical performance of dental adhesive systems, it is well accepted that NCCLs are ideal model cavities . The main reasons are as follows: easy to find during patient selection; small C-factor and lack of macromechanical retention ; simple to restore, which reduces the effect of operator variability ; and finally, the dentin substrate presents a high degree of sclerosis that turns the adhesion a challenging procedure .

Therefore, the aim of the present systematic review was to verify whether the presence of the monomer HEMA in the formulation of adhesive systems has an influence on the clinical performance of noncarious cervical lesion (NCCL) restorations.

Materials and methods

Protocol and registration

This study protocol was registered at the Prospective Register of Systematic Review (PROSPERO – CRD42016044086), and it followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement for the report of this systematic review .

Information sources and search strategy

The Medical Subject Headings (MeSH) terms, synonyms, and free keywords in the search strategy were defined on the basis of the following PICOS question:

  • 1.

    Population (P): adult patients with noncarious cervical lesions (NCCLs)

  • 2.

    Intervention (I): composite resin restorations placed in NCCLs with HEMA-free adhesive systems

  • 3.

    Comparison (C): Control: composite resin restorations in NCCLs with HEMA-containing adhesive systems.

  • 4.

    Outcome (O): clinical performance of restorations; however, no outcome was used in the search strategy to maximize it.

  • 5.

    Study design (S): randomized controlled clinical trials

To identify the articles to be included for this review, an electronic search was developed for the following databases: MEDLINE through PubMed, Web of Science, Open Grey, Scopus, and Cochrane Library. No restrictions were applied on the publication date and languages. Articles published up to May 2017 were considered for this review. A minimum follow-up of one year was required for evaluation. A hand search was performed, and the reference lists of included articles were examined to verify whether there were additional relevant studies that were not found during database searches.

The search strategies were defined appropriately for each database ( Table 1 ). These search strategies were independently performed by two reviewers (TSPS and RFCV) to identify eligible studies. Full-text versions of all articles that appeared to meet the inclusion criteria were obtained for subsequent evaluation and data extraction.

Table 1
Electronic Database and Search Strategy.
PubMed (19/05/2017)
#1 (tooth erosion[MeSH Terms]) OR tooth erosion*[Title/Abstract]) OR teeth erosion*[Title/Abstract]) OR tooth abrasion[MeSH Terms]) OR tooth abrasion*[Title/Abstract]) OR teeth abrasion*[Title/Abstract]) OR dental abrasion*[Title/Abstract]) OR tooth wear[MeSH Terms]) OR tooth wear*[Title/Abstract]) OR teeth wear*[Title/Abstract]) OR dental wear*[Title/Abstract]) OR tooth abfraction*[Title/Abstract]) OR teeth abfraction*[Title/Abstract]) OR Permanent dental restorations[MeSH Terms]) OR Permanent dental restoration*[Title/Abstract]) OR Permanent Dental Filling*[Title/Abstract]) OR NCCL*[Title/Abstract]) OR noncarious cervical lesion*[Title/Abstract]) OR non-carious cervical lesion*[Title/Abstract]) OR non carious cervical lesion*[Title/Abstract]) OR cervical lesion*[Title/Abstract]) OR class V lesion*[Title/Abstract]) OR cervical restoration*[Title/Abstract]) OR class V restoration*[Title/Abstract] #2 (hydroxyethyl methacrylate[MeSH Terms]) OR Bis-GMA, BPDM, HEMA dental-bonding resin[MeSH Terms]) OR Bisphenol A-Glycidyl Methacrylate[MeSH Terms]) OR methacrylates[MeSH Terms]) OR Dentin-Bonding Agents[MeSH Terms]) OR Dental bonding[MeSH Terms]) OR hydroxyethyl methacrylate*[Title/Abstract]) OR 2-hydroxyethyl methacrylate*[Title/Abstract]) OR HEMA[Title/Abstract]) OR HEMA free[Title/Abstract] OR HEMA-free[Title/Abstract] OR Bis-GMA[Title/Abstract]) OR Bis GMA[Title/Abstract]) OR Bis-GMA, BPDM, HEMA dental-bonding resin*[Title/Abstract]) OR Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin*[Title/Abstract]) OR One-Step Plus dentin bonding system*[Title/Abstract]) OR One-Step dentin bonding system*[Title/Abstract]) OR Bisphenol A-Glycidyl Methacrylate*[Title/Abstract]) OR Bisphenol A Glycidyl Methacrylate*[Title/Abstract]) OR Methacrylate*[Title/Abstract]) OR Dentin Bonding Agent*[Title/Abstract]) OR Dentin-Bonding Agent*[Title/Abstract]) OR Dental bonding[Title/Abstract]) OR HEMA rich[Title/Abstract]) OR HEMA-rich[Title/Abstract]) OR HEMA containing[Title/Abstract]) OR HEMA adhesive*[Title/Abstract]) OR bonding system*[Title/Abstract]) OR dental bonding agent*[Title/Abstract] #3 (clinical trial[MeSH Terms]) OR clinical study[MeSH Terms]) OR prospective studies[MeSH Terms]) OR longitudinal studies[MeSH Terms]) OR controlled clinical trial[MeSH Terms]) OR randomized controlled trial[MeSH Terms]) OR observational study[MeSH Terms]) OR Clinical*[Title/Abstract]) OR trial*[Title/Abstract]) OR clinical trial*[Title/Abstract]) OR clinical stud*[Title/Abstract]) OR prospective evaluation*[Title/Abstract]) OR prospective stud*[Title/Abstract]) OR controlled clinical trial*[Title/Abstract]) OR longitudinal stud*[Title/Abstract]) OR longitudinal survey*[Title/Abstract]) OR randomized controlled trial*[Title/Abstract]) OR observational stud*[Title/Abstract]
#1 AND #2 AND #3
SCOPUS (19/05/2017)
#1 (TITLE-ABS-KEY (“tooth erosion”) OR TITLE-ABS-KEY (“teeth erosion”) OR TITLE-ABS-KEY (“tooth abrasion”) OR TITLE-ABS-KEY (“teeth abrasion”) OR TITLE-ABS-KEY(“dental abrasion”) OR TITLE-ABS-KEY (“tooth wear”) OR TITLE-ABS-KEY (“teeth wear”) OR TITLE-ABS-KEY (“dental wear”) OR TITLE-ABS-KEY (“tooth abfraction”) OR TITLE-ABS-KEY (“teeth abfraction”) OR TITLE-ABS-KEY (“permanent dental restoration”) OR TITLE-ABS-KEY (“permanent dental filling”) OR TITLE-ABS-KEY (nccl) OR TITLE-ABS-KEY (“cervical lesion”) OR TITLE-ABS-KEY (“cervical lesions”) OR TITLE-ABS-KEY (“noncarious cervical lesion””) OR TITLE-ABS-KEY (“non-carious cervical lesion”) OR TITLE-ABS-KEY (“non carious cervical lesion”) OR TITLE-ABS-KEY (“class V lesion”) OR TITLE-ABS-KEY (“class V lesions”) OR TITLE-ABS-KEY (“cervical restoration”) OR TITLE-ABS-KEY (“cervical restorations”) OR TITLE-ABS-KEY (“permanent dental restorations”) OR TITLE-ABS-KEY (“class V restorations”) OR TITLE-ABS-KEY (“class V restoration”) #2 (TITLE-ABS-KEY (“hydroxyethyl methacrylate”) OR TITLE-ABS-KEY (“2-hydroxyethyl methacrylate”) OR TITLE-ABS-KEY (hema) OR TITLE-ABS-KEY (“Bis-GMA, BPDM, HEMA dental-bonding resin”) OR TITLE-ABS-KEY (“Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin”) OR TITLE-ABS-KEY (“One-step plus dentin bonding system”) OR TITLE-ABS-KEY (“One-step dentin bonding system”) OR TITLE-ABS-KEY (“Bisphenol A-Glycidyl Methacrylate”) OR TITLE-ABS-KEY (“Bisphenol A Glycidyl Methacrylate”) OR TITLE-ABS-KEY (bis-gma) OR TITLE-ABS-KEY (Bis GMA) OR TITLE-ABS-KEY (methacrylate) OR TITLE-ABS-KEY (methacrylates) OR TITLE-ABS-KEY (“dentin-bonding agent”) OR TITLE-ABS-KEY (“dentin-bonding agents”) OR TITLE-ABS-KEY (“dentin bonding agent”) OR TITLE-ABS-KEY (“dentin bonding agents”) OR TITLE-ABS-KEY (“dental bonding”) OR TITLE-ABS-KEY (“HEMA rich”) OR TITLE-ABS-KEY (“HEMA-rich”) OR TITLE-ABS-KEY (“HEMA containing”) OR TITLE-ABS-KEY (“HEMA adhesive”) OR TITLE-ABS-KEY (“HEMA adhesives”) OR TITLE-ABS-KEY (“bonding system”) OR TITLE-ABS-KEY (“bonding systems”) OR TITLE-ABS-KEY (“dental bonding agent”) OR TITLE-ABS-KEY (“dental bonding agents”)) #3 (TITLE-ABS-KEY (“clinical trial”) OR TITLE-ABS-KEY (clinical) OR TITLE-ABS-KEY (trial) OR TITLE-ABS-KEY (“clinical study”) OR TITLE-ABS-KEY (“clinical studies”) OR TITLE-ABS-KEY (“prospective evaluation”) OR TITLE-ABS-KEY (“prospective study”) OR TITLE-ABS-KEY (“prospective studies”) OR TITLE-ABS-KEY (“longitudinal survey”) OR TITLE-ABS-KEY (“controlled clinical trial”) OR TITLE-ABS-KEY (“randomized controlled clinical trial”) OR TITLE-ABS-KEY (“observational study”) OR TITLE-ABS-KEY (“observational studies”) OR TITLE-ABS-KEY (“longitudinal study”) OR TITLE-ABS-KEY (“longitudinal studies”)
#1 AND #2 AND #3
Web of Science (19/05/2017)
#1 ((tooth erosion) OR (teeth erosion) OR (tooth abrasion) OR (teeth abrasion) OR (dental abrasion) OR (tooth wear) OR (teeth wear) OR (dental wear) OR (tooth abfraction) OR (teeth abfraction) OR (permanent dental restoration*) OR (permanent dental filling) OR (NCCL) OR (cervical lesion*) OR (non carious cervical lesion*) OR (non*carious cervical lesion*) OR (class V lesion*) OR (cervical restoration*) OR (class V restoration*)) #2 (hydroxyethyl methacrylate) OR (2-hydroxyethyl methacrylate) OR (HEMA) OR (Bis-GMA, BPDM, HEMA dental-bonding resin) OR (Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin) OR (One-Step Plus dentin bonding system) OR (One-Step dentin bonding system) OR (Bisphenol A-Glycidyl Methacrylate) OR (Bisphenol A Glycidyl Methacrylate) OR (Bis-GMA) OR (Bis GMA) OR (methacrylate*) OR (Dentin-Bonding Agent*) OR (Dentin Bonding Agent*) OR (Dental bonding) OR (HEMA rich) OR (HEMA-rich) OR (HEMA containing) OR (HEMA adhesive*) OR (bonding system*) OR (dental bonding agent*) #3 (clinical trial) OR (clinical) OR (trial) (clinical stud*) OR (prospective evaluation) OR (prospective stud*) OR (longitudinal survey*) OR (controlled clinical trial) OR (randomized controlled clinical trial) OR (observational stud*) OR (longitudinal stud*)
#1 AND #2 AND #3
Cochrane Library (19/05/2017)
#1 “tooth erosion*” OR “teeth erosion*” OR “tooth abrasion*” OR “teeth abrasion*” OR “tooth abfraction*” OR “teeth abfraction*” OR “tooth wear*” OR teeth wear*” OR “dental abrasion*” OR “class V restoration*” OR class V lesion*” OR NCCL* OR “cervical restoration*” OR “cervical lesion*” OR “noncarious cervical lesion*” OR “non-carious cervical lesion*” OR “non carious cervical lesion*” OR “Permanent dental restoration*” OR “Permanent dental filling*” #2 “hydroxyethyl methacrylate*” OR “Bis-GMA, BPDM, HEMA dental-bonding resin*” OR “Bisphenol A-Glycidyl Methacrylate*” OR “methacrylate*” OR “Dentin-Bonding Agent*” OR “Dental bonding*” OR “2-hydroxyethyl methacrylate*” OR HEMA OR “HEMA-free” OR “Bis-GMA” OR “Bis GMA” OR “Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin*” OR “One-Step Plus dentin bonding system*” OR “One-Step dentin bonding system*” OR “Bisphenol A Glycidyl Methacrylate*” OR “Dentin Bonding Agent*” OR “Dentin-bonding agent*” OR “Dental bonding*” OR “HEMA rich” OR “HEMA-rich” OR “HEMA containing” OR “HEMA adhesive*” OR “bonding system*’ OR ‘dental bonding agent*’ #3 “clinical trial*” OR “clinical stud*” OR “prospective stud*” OR “longitudinal stud*” OR “controlled clinical trial*” OR “randomized controlled trial*” OR “observational stud*” OR “clinical*” OR “trial*” OR “prospective evaluation*” OR “longitudinal stud*” OR “longitudinal survey*”
#1 AND #2 AND #3
Open Grey (19/05/2017)
#1 (“tooth erosion*” OR “teeth erosion*” OR “Tooth abrasion*” OR “teeth abrasion*” OR “dental abrasion*” OR “tooth wear*” OR “teeth wear*” OR “dental wear*” OR “tooth abfraction*” OR “teeth abfraction*” OR “Permanent dental restoration*” OR “Permanent Dental Filling*” OR NCCL* OR “noncarious cervical lesion*” OR “non-carious cervical lesion*” OR “non carious cervical lesion*” OR “cervical lesion*” OR “class V lesion*” OR “cervical restoration*” OR “class V restoration*”) #2 (“hydroxyethyl methacrylate*” OR “2-hydroxyethyl methacrylate*” OR HEMA OR “Bis-GMA, BPDM, HEMA dental-bonding resin*” OR “Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin*” OR “One-Step Plus dentin bonding system*” OR “One-Step dentin bonding system*” OR “Bisphenol A-Glycidyl Methacrylate*” OR “Bisphenol A Glycidyl Methacrylate*” OR “Bis-GMA” OR “Bis GMA” OR “methacrylate*” OR “Dentin-Bonding Agent*” OR “Dentin Bonding Agent*” OR “Dental bonding” OR “HEMA rich” OR “HEMA-rich” OR “HEMA containing” OR “HEMA adhesive*” OR “bonding system*” OR “dental bonding agent*”) #3 (“HEMA-free system*” OR “HEMA free system*” OR “HEMA-free adhesive system*” OR “HEMA free adhesive system*” OR “HEMA-free formulation*” OR “HEMA free formulation*”)
#1 AND #2 AND #3

Eligibility criteria

In this review, RCTs comparing the clinical effectiveness of HEMA-free and HEMA-containing adhesive systems for direct resin composite restoration of NCCLs in the permanent dentition of adult patients (male and female) of any age group were included.

Editorial letters; historical reviews; pilot studies; in vitro studies; and cohort, observational, and descriptive studies such as case reports and case series were excluded.

Study selection and data collection process

According to the described search strategy, the selection of articles was first performed by title and abstract. If articles appeared in more than one database, they were included only once. Full-text articles were obtained when there was no sufficient information in the title and abstract. Subsequently, two reviewers classified the articles that met the inclusion criteria. Each eligible study received an ID combining the first author and year of publication.

Relevant details about the study design, participants, interventions, and outcome were extracted using customized extraction forms. If there were reports of the same study with different follow-ups, the extraction of data was performed using data from the largest follow-up period. When there was lack of data in the articles, authors were contacted weekly through email at least five times, to request the missing information.

Risk of bias in individual studies

The Cochrane Collaboration’s tool for assessing risk of bias in RCTs was used by two independent reviewers to perform the quality assessment of the trials. The assessment criteria contained six items: sequence generation, allocation concealment, blinding of the outcome assessor, incomplete outcome data, selective outcome reporting, and other possible sources of bias. Any disagreement between the reviewers during data selection and quality assessment had to be discussed until an agreement was reached. If necessary, a third reviewer was called (LCM).

The risk of bias for each domain of the quality assessment was scored following recommendations as described in the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 ( ). For each entry, the judgment involved recording “yes” indicating minimal risk of bias, “no” indicating elevated risk of bias, and “unclear” indicating either lack of information or uncertainty over the potential for bias.

At the study level, sequence generation, allocation concealment, and blinding of the outcome assessment were considered the key domains for the assessment of the risk of bias. To be considered at “low” risk of bias, studies should present low risk of bias in all key domains. If the study was considered “unclear” in their key domains, authors were contacted to obtain more information to allow a definitive judgment. When one or more of these criteria were classified as “unclear” or at “high” risk of bias, the whole study was considered as unclear or at high risk of bias, respectively.

Summary measures and synthesis of the results

The extracted data were analyzed using RevMan software (Review Manager v. 5.3; The Cochrane Collaboration; Copenhagen, Denmark). The meta-analysis was performed including “low and unclear risk of bias” studies. The meta-analysis was subgrouped according to the main parameters analyzed: (retention [RE], marginal adaptation [MA], marginal discoloration [MD], caries [CA], and postoperative sensitivity [POS]). Each parameter and the overall effect (clinical performance) were analyzed.

The data were dichotomized into “acceptable” or “unacceptable” according to the classification criteria used by each study. The prevalence of unacceptable (failures/events) and the total number of restorations for each group were used to calculate the risk difference with a 95% confidence interval (CI). Random effects models were employed, and heterogeneity was tested using the I 2 index.

If some of the information needed for the meta-analysis was absent from any of the selected studies, the authors were contacted to provide the missing data. Five attempts of contacts with authors were made for each study. If after the contact attempts there was no response from the authors, or the authors did not provide the data, the study was not included in the meta-analysis.

Materials and methods

Protocol and registration

This study protocol was registered at the Prospective Register of Systematic Review (PROSPERO – CRD42016044086), and it followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement for the report of this systematic review .

Information sources and search strategy

The Medical Subject Headings (MeSH) terms, synonyms, and free keywords in the search strategy were defined on the basis of the following PICOS question:

  • 1.

    Population (P): adult patients with noncarious cervical lesions (NCCLs)

  • 2.

    Intervention (I): composite resin restorations placed in NCCLs with HEMA-free adhesive systems

  • 3.

    Comparison (C): Control: composite resin restorations in NCCLs with HEMA-containing adhesive systems.

  • 4.

    Outcome (O): clinical performance of restorations; however, no outcome was used in the search strategy to maximize it.

  • 5.

    Study design (S): randomized controlled clinical trials

To identify the articles to be included for this review, an electronic search was developed for the following databases: MEDLINE through PubMed, Web of Science, Open Grey, Scopus, and Cochrane Library. No restrictions were applied on the publication date and languages. Articles published up to May 2017 were considered for this review. A minimum follow-up of one year was required for evaluation. A hand search was performed, and the reference lists of included articles were examined to verify whether there were additional relevant studies that were not found during database searches.

The search strategies were defined appropriately for each database ( Table 1 ). These search strategies were independently performed by two reviewers (TSPS and RFCV) to identify eligible studies. Full-text versions of all articles that appeared to meet the inclusion criteria were obtained for subsequent evaluation and data extraction.

Table 1
Electronic Database and Search Strategy.
PubMed (19/05/2017)
#1 (tooth erosion[MeSH Terms]) OR tooth erosion*[Title/Abstract]) OR teeth erosion*[Title/Abstract]) OR tooth abrasion[MeSH Terms]) OR tooth abrasion*[Title/Abstract]) OR teeth abrasion*[Title/Abstract]) OR dental abrasion*[Title/Abstract]) OR tooth wear[MeSH Terms]) OR tooth wear*[Title/Abstract]) OR teeth wear*[Title/Abstract]) OR dental wear*[Title/Abstract]) OR tooth abfraction*[Title/Abstract]) OR teeth abfraction*[Title/Abstract]) OR Permanent dental restorations[MeSH Terms]) OR Permanent dental restoration*[Title/Abstract]) OR Permanent Dental Filling*[Title/Abstract]) OR NCCL*[Title/Abstract]) OR noncarious cervical lesion*[Title/Abstract]) OR non-carious cervical lesion*[Title/Abstract]) OR non carious cervical lesion*[Title/Abstract]) OR cervical lesion*[Title/Abstract]) OR class V lesion*[Title/Abstract]) OR cervical restoration*[Title/Abstract]) OR class V restoration*[Title/Abstract] #2 (hydroxyethyl methacrylate[MeSH Terms]) OR Bis-GMA, BPDM, HEMA dental-bonding resin[MeSH Terms]) OR Bisphenol A-Glycidyl Methacrylate[MeSH Terms]) OR methacrylates[MeSH Terms]) OR Dentin-Bonding Agents[MeSH Terms]) OR Dental bonding[MeSH Terms]) OR hydroxyethyl methacrylate*[Title/Abstract]) OR 2-hydroxyethyl methacrylate*[Title/Abstract]) OR HEMA[Title/Abstract]) OR HEMA free[Title/Abstract] OR HEMA-free[Title/Abstract] OR Bis-GMA[Title/Abstract]) OR Bis GMA[Title/Abstract]) OR Bis-GMA, BPDM, HEMA dental-bonding resin*[Title/Abstract]) OR Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin*[Title/Abstract]) OR One-Step Plus dentin bonding system*[Title/Abstract]) OR One-Step dentin bonding system*[Title/Abstract]) OR Bisphenol A-Glycidyl Methacrylate*[Title/Abstract]) OR Bisphenol A Glycidyl Methacrylate*[Title/Abstract]) OR Methacrylate*[Title/Abstract]) OR Dentin Bonding Agent*[Title/Abstract]) OR Dentin-Bonding Agent*[Title/Abstract]) OR Dental bonding[Title/Abstract]) OR HEMA rich[Title/Abstract]) OR HEMA-rich[Title/Abstract]) OR HEMA containing[Title/Abstract]) OR HEMA adhesive*[Title/Abstract]) OR bonding system*[Title/Abstract]) OR dental bonding agent*[Title/Abstract] #3 (clinical trial[MeSH Terms]) OR clinical study[MeSH Terms]) OR prospective studies[MeSH Terms]) OR longitudinal studies[MeSH Terms]) OR controlled clinical trial[MeSH Terms]) OR randomized controlled trial[MeSH Terms]) OR observational study[MeSH Terms]) OR Clinical*[Title/Abstract]) OR trial*[Title/Abstract]) OR clinical trial*[Title/Abstract]) OR clinical stud*[Title/Abstract]) OR prospective evaluation*[Title/Abstract]) OR prospective stud*[Title/Abstract]) OR controlled clinical trial*[Title/Abstract]) OR longitudinal stud*[Title/Abstract]) OR longitudinal survey*[Title/Abstract]) OR randomized controlled trial*[Title/Abstract]) OR observational stud*[Title/Abstract]
#1 AND #2 AND #3
SCOPUS (19/05/2017)
#1 (TITLE-ABS-KEY (“tooth erosion”) OR TITLE-ABS-KEY (“teeth erosion”) OR TITLE-ABS-KEY (“tooth abrasion”) OR TITLE-ABS-KEY (“teeth abrasion”) OR TITLE-ABS-KEY(“dental abrasion”) OR TITLE-ABS-KEY (“tooth wear”) OR TITLE-ABS-KEY (“teeth wear”) OR TITLE-ABS-KEY (“dental wear”) OR TITLE-ABS-KEY (“tooth abfraction”) OR TITLE-ABS-KEY (“teeth abfraction”) OR TITLE-ABS-KEY (“permanent dental restoration”) OR TITLE-ABS-KEY (“permanent dental filling”) OR TITLE-ABS-KEY (nccl) OR TITLE-ABS-KEY (“cervical lesion”) OR TITLE-ABS-KEY (“cervical lesions”) OR TITLE-ABS-KEY (“noncarious cervical lesion””) OR TITLE-ABS-KEY (“non-carious cervical lesion”) OR TITLE-ABS-KEY (“non carious cervical lesion”) OR TITLE-ABS-KEY (“class V lesion”) OR TITLE-ABS-KEY (“class V lesions”) OR TITLE-ABS-KEY (“cervical restoration”) OR TITLE-ABS-KEY (“cervical restorations”) OR TITLE-ABS-KEY (“permanent dental restorations”) OR TITLE-ABS-KEY (“class V restorations”) OR TITLE-ABS-KEY (“class V restoration”) #2 (TITLE-ABS-KEY (“hydroxyethyl methacrylate”) OR TITLE-ABS-KEY (“2-hydroxyethyl methacrylate”) OR TITLE-ABS-KEY (hema) OR TITLE-ABS-KEY (“Bis-GMA, BPDM, HEMA dental-bonding resin”) OR TITLE-ABS-KEY (“Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin”) OR TITLE-ABS-KEY (“One-step plus dentin bonding system”) OR TITLE-ABS-KEY (“One-step dentin bonding system”) OR TITLE-ABS-KEY (“Bisphenol A-Glycidyl Methacrylate”) OR TITLE-ABS-KEY (“Bisphenol A Glycidyl Methacrylate”) OR TITLE-ABS-KEY (bis-gma) OR TITLE-ABS-KEY (Bis GMA) OR TITLE-ABS-KEY (methacrylate) OR TITLE-ABS-KEY (methacrylates) OR TITLE-ABS-KEY (“dentin-bonding agent”) OR TITLE-ABS-KEY (“dentin-bonding agents”) OR TITLE-ABS-KEY (“dentin bonding agent”) OR TITLE-ABS-KEY (“dentin bonding agents”) OR TITLE-ABS-KEY (“dental bonding”) OR TITLE-ABS-KEY (“HEMA rich”) OR TITLE-ABS-KEY (“HEMA-rich”) OR TITLE-ABS-KEY (“HEMA containing”) OR TITLE-ABS-KEY (“HEMA adhesive”) OR TITLE-ABS-KEY (“HEMA adhesives”) OR TITLE-ABS-KEY (“bonding system”) OR TITLE-ABS-KEY (“bonding systems”) OR TITLE-ABS-KEY (“dental bonding agent”) OR TITLE-ABS-KEY (“dental bonding agents”)) #3 (TITLE-ABS-KEY (“clinical trial”) OR TITLE-ABS-KEY (clinical) OR TITLE-ABS-KEY (trial) OR TITLE-ABS-KEY (“clinical study”) OR TITLE-ABS-KEY (“clinical studies”) OR TITLE-ABS-KEY (“prospective evaluation”) OR TITLE-ABS-KEY (“prospective study”) OR TITLE-ABS-KEY (“prospective studies”) OR TITLE-ABS-KEY (“longitudinal survey”) OR TITLE-ABS-KEY (“controlled clinical trial”) OR TITLE-ABS-KEY (“randomized controlled clinical trial”) OR TITLE-ABS-KEY (“observational study”) OR TITLE-ABS-KEY (“observational studies”) OR TITLE-ABS-KEY (“longitudinal study”) OR TITLE-ABS-KEY (“longitudinal studies”)
#1 AND #2 AND #3
Web of Science (19/05/2017)
#1 ((tooth erosion) OR (teeth erosion) OR (tooth abrasion) OR (teeth abrasion) OR (dental abrasion) OR (tooth wear) OR (teeth wear) OR (dental wear) OR (tooth abfraction) OR (teeth abfraction) OR (permanent dental restoration*) OR (permanent dental filling) OR (NCCL) OR (cervical lesion*) OR (non carious cervical lesion*) OR (non*carious cervical lesion*) OR (class V lesion*) OR (cervical restoration*) OR (class V restoration*)) #2 (hydroxyethyl methacrylate) OR (2-hydroxyethyl methacrylate) OR (HEMA) OR (Bis-GMA, BPDM, HEMA dental-bonding resin) OR (Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin) OR (One-Step Plus dentin bonding system) OR (One-Step dentin bonding system) OR (Bisphenol A-Glycidyl Methacrylate) OR (Bisphenol A Glycidyl Methacrylate) OR (Bis-GMA) OR (Bis GMA) OR (methacrylate*) OR (Dentin-Bonding Agent*) OR (Dentin Bonding Agent*) OR (Dental bonding) OR (HEMA rich) OR (HEMA-rich) OR (HEMA containing) OR (HEMA adhesive*) OR (bonding system*) OR (dental bonding agent*) #3 (clinical trial) OR (clinical) OR (trial) (clinical stud*) OR (prospective evaluation) OR (prospective stud*) OR (longitudinal survey*) OR (controlled clinical trial) OR (randomized controlled clinical trial) OR (observational stud*) OR (longitudinal stud*)
#1 AND #2 AND #3
Cochrane Library (19/05/2017)
#1 “tooth erosion*” OR “teeth erosion*” OR “tooth abrasion*” OR “teeth abrasion*” OR “tooth abfraction*” OR “teeth abfraction*” OR “tooth wear*” OR teeth wear*” OR “dental abrasion*” OR “class V restoration*” OR class V lesion*” OR NCCL* OR “cervical restoration*” OR “cervical lesion*” OR “noncarious cervical lesion*” OR “non-carious cervical lesion*” OR “non carious cervical lesion*” OR “Permanent dental restoration*” OR “Permanent dental filling*” #2 “hydroxyethyl methacrylate*” OR “Bis-GMA, BPDM, HEMA dental-bonding resin*” OR “Bisphenol A-Glycidyl Methacrylate*” OR “methacrylate*” OR “Dentin-Bonding Agent*” OR “Dental bonding*” OR “2-hydroxyethyl methacrylate*” OR HEMA OR “HEMA-free” OR “Bis-GMA” OR “Bis GMA” OR “Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin*” OR “One-Step Plus dentin bonding system*” OR “One-Step dentin bonding system*” OR “Bisphenol A Glycidyl Methacrylate*” OR “Dentin Bonding Agent*” OR “Dentin-bonding agent*” OR “Dental bonding*” OR “HEMA rich” OR “HEMA-rich” OR “HEMA containing” OR “HEMA adhesive*” OR “bonding system*’ OR ‘dental bonding agent*’ #3 “clinical trial*” OR “clinical stud*” OR “prospective stud*” OR “longitudinal stud*” OR “controlled clinical trial*” OR “randomized controlled trial*” OR “observational stud*” OR “clinical*” OR “trial*” OR “prospective evaluation*” OR “longitudinal stud*” OR “longitudinal survey*”
#1 AND #2 AND #3
Open Grey (19/05/2017)
#1 (“tooth erosion*” OR “teeth erosion*” OR “Tooth abrasion*” OR “teeth abrasion*” OR “dental abrasion*” OR “tooth wear*” OR “teeth wear*” OR “dental wear*” OR “tooth abfraction*” OR “teeth abfraction*” OR “Permanent dental restoration*” OR “Permanent Dental Filling*” OR NCCL* OR “noncarious cervical lesion*” OR “non-carious cervical lesion*” OR “non carious cervical lesion*” OR “cervical lesion*” OR “class V lesion*” OR “cervical restoration*” OR “class V restoration*”) #2 (“hydroxyethyl methacrylate*” OR “2-hydroxyethyl methacrylate*” OR HEMA OR “Bis-GMA, BPDM, HEMA dental-bonding resin*” OR “Bis-GMA, biphenyl dimethacrylate, hydroxyethyl methacrylate dental resin*” OR “One-Step Plus dentin bonding system*” OR “One-Step dentin bonding system*” OR “Bisphenol A-Glycidyl Methacrylate*” OR “Bisphenol A Glycidyl Methacrylate*” OR “Bis-GMA” OR “Bis GMA” OR “methacrylate*” OR “Dentin-Bonding Agent*” OR “Dentin Bonding Agent*” OR “Dental bonding” OR “HEMA rich” OR “HEMA-rich” OR “HEMA containing” OR “HEMA adhesive*” OR “bonding system*” OR “dental bonding agent*”) #3 (“HEMA-free system*” OR “HEMA free system*” OR “HEMA-free adhesive system*” OR “HEMA free adhesive system*” OR “HEMA-free formulation*” OR “HEMA free formulation*”)
#1 AND #2 AND #3

Eligibility criteria

In this review, RCTs comparing the clinical effectiveness of HEMA-free and HEMA-containing adhesive systems for direct resin composite restoration of NCCLs in the permanent dentition of adult patients (male and female) of any age group were included.

Editorial letters; historical reviews; pilot studies; in vitro studies; and cohort, observational, and descriptive studies such as case reports and case series were excluded.

Study selection and data collection process

According to the described search strategy, the selection of articles was first performed by title and abstract. If articles appeared in more than one database, they were included only once. Full-text articles were obtained when there was no sufficient information in the title and abstract. Subsequently, two reviewers classified the articles that met the inclusion criteria. Each eligible study received an ID combining the first author and year of publication.

Relevant details about the study design, participants, interventions, and outcome were extracted using customized extraction forms. If there were reports of the same study with different follow-ups, the extraction of data was performed using data from the largest follow-up period. When there was lack of data in the articles, authors were contacted weekly through email at least five times, to request the missing information.

Risk of bias in individual studies

The Cochrane Collaboration’s tool for assessing risk of bias in RCTs was used by two independent reviewers to perform the quality assessment of the trials. The assessment criteria contained six items: sequence generation, allocation concealment, blinding of the outcome assessor, incomplete outcome data, selective outcome reporting, and other possible sources of bias. Any disagreement between the reviewers during data selection and quality assessment had to be discussed until an agreement was reached. If necessary, a third reviewer was called (LCM).

The risk of bias for each domain of the quality assessment was scored following recommendations as described in the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 ( ). For each entry, the judgment involved recording “yes” indicating minimal risk of bias, “no” indicating elevated risk of bias, and “unclear” indicating either lack of information or uncertainty over the potential for bias.

At the study level, sequence generation, allocation concealment, and blinding of the outcome assessment were considered the key domains for the assessment of the risk of bias. To be considered at “low” risk of bias, studies should present low risk of bias in all key domains. If the study was considered “unclear” in their key domains, authors were contacted to obtain more information to allow a definitive judgment. When one or more of these criteria were classified as “unclear” or at “high” risk of bias, the whole study was considered as unclear or at high risk of bias, respectively.

Summary measures and synthesis of the results

The extracted data were analyzed using RevMan software (Review Manager v. 5.3; The Cochrane Collaboration; Copenhagen, Denmark). The meta-analysis was performed including “low and unclear risk of bias” studies. The meta-analysis was subgrouped according to the main parameters analyzed: (retention [RE], marginal adaptation [MA], marginal discoloration [MD], caries [CA], and postoperative sensitivity [POS]). Each parameter and the overall effect (clinical performance) were analyzed.

The data were dichotomized into “acceptable” or “unacceptable” according to the classification criteria used by each study. The prevalence of unacceptable (failures/events) and the total number of restorations for each group were used to calculate the risk difference with a 95% confidence interval (CI). Random effects models were employed, and heterogeneity was tested using the I 2 index.

If some of the information needed for the meta-analysis was absent from any of the selected studies, the authors were contacted to provide the missing data. Five attempts of contacts with authors were made for each study. If after the contact attempts there was no response from the authors, or the authors did not provide the data, the study was not included in the meta-analysis.

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Jun 17, 2018 | Posted by in General Dentistry | Comments Off on Do HEMA-free adhesive systems have better clinical performance than HEMA-containing systems in noncarious cervical lesions? A systematic review and meta-analysis
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