Dental Hypotheses

: 2021  |  Volume : 12  |  Issue : 1  |  Page : 22--27

Clinical Comparison of Fissure Sealants Retention Following Preparation with Seventh Generation Bonding Agent with Prior Etching and Conventional Acid Etch and Bond System (fifth Generation)

Leila Erfanparast1, Masoumeh Vatandoust2, Azin Sohrabi2, Leila Mahmoudi3,  
1 Associate Professor, Department of Pediatric Dentistry, Tabriz University of Medical Science, Tabriz, Iran
2 Aassistant Professor, Department of Pediatric Dentistry, Tabriz University of Medical Science, Tabriz, Iran
3 Dentist, Department of Pediatric Dentistry, Tabriz University of Medical Science, Tabriz, Iran

Correspondence Address:
Azin Sohrabi
Assistant Professor, Department of Pediatric Dentistry, Tabriz University of Medical Science, Tabriz


Introduction: Fissure sealant therapy is a preventive method relied on covering pits and fissures to prohibit bacteria from settling on tooth and producing acid, which cause tooth demineralization. The benefits of caries prevention could only be achieved when the sealants remain intact for a long time, thus long-lasting retention is mandatory. Despite recently achieved improvement in sealant quality, their retention in long course remains a challenging issue in dentistry. The purpose of our study was to compare the clinical efficacy of sealants after using seventh generation adhesive and additional etchant material with fifth generation bonding agent. Materials and Methods: In this randomized clinical trial, 40 patients in the age group of 7 to 12 years were randomly selected. All participants had a pair of sound first permanent molar in the mandible, which need fissure sealant therapy. For each patient, one tooth was treated with seventh generation bonding and separate etching material, and the counterpart tooth had undergone the fifth generation bonding system. A pediatric dentist did exert 6 and 12-mounth follow ups. Results: In 38 of 40 patients, who completed 6-month follow-up, the success rate of seventh generation adhesive was 84.2% and in the fifth generation group it was 76.3%. At 12-month follow-up, 36 patients were referred and success rate of fifth generation bonding was 52% and it was 36% in seventh generation adhesive. According to fisher test, the difference between two groups was not statistically significant. Conclusion: This study depicted that fissure sealant retention was equal after 6 and 12 months in both methods.

How to cite this article:
Erfanparast L, Vatandoust M, Sohrabi A, Mahmoudi L. Clinical Comparison of Fissure Sealants Retention Following Preparation with Seventh Generation Bonding Agent with Prior Etching and Conventional Acid Etch and Bond System (fifth Generation).Dent Hypotheses 2021;12:22-27

How to cite this URL:
Erfanparast L, Vatandoust M, Sohrabi A, Mahmoudi L. Clinical Comparison of Fissure Sealants Retention Following Preparation with Seventh Generation Bonding Agent with Prior Etching and Conventional Acid Etch and Bond System (fifth Generation). Dent Hypotheses [serial online] 2021 [cited 2021 Apr 15 ];12:22-27
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The sense of need for clogging susceptible spots on tooth, which could trap foods and dental plaque and subsequently develop caries has a long history in dentistry. In 1924, Thaddeus Hyatt proposed prophylactic restorations performed as Class I cavity preparations, which included all caries susceptible areas. These preparations should be filled by amalgam restoration for caries prevention in pits and fissures. A few years later, in 1929, another more conservative method was introduced by Mr. Bodercker. At first, he suggested filling the fissures with a tooth-colored material, oxyphosphate cement, following cleaning the fissures with dental explorer without any cavity preparation. Then, he brought in a new method called prophylactic odontomy comprising mechanical broadening of pits and fissures with dental bar to intensify self-cleansing properties of tooth.[1] Nowadays, conventional fissure sealant therapy is a preventive method and uses resin materials on sound pits and fissures, which could not present any self-cleansing features; it could usually be performed without cavity preparation.[2],[3] Fissure sealants have three important preventive effects:

They mechanically fill fissures with acid-resistant resin.

Streptococcus mutan and other caries-related microorganisms get deprived of their habitat because of fissure blockage by resin.

These materials facilitate the cleaning of pits and fissures by leaving an even surface in occlusal area.[4]

The clinical success of sealants in preventing caries is strongly associated with their retention. Various methods have been exploited to increase sealant retention, including air-abrasion by aluminum oxide particles, laser systems, and finally applying resin bonding agents in tooth-sealant interface.[5] Recent studies have come to the result that applying etchant agent before using bonding conspicuously improves the adhesion between enamel and resin.[3]

The most common classification for bonding systems is based on the time of their release, which basically divides them into eight generations, but this classification has no scientific background and categories that make classification according to clinical steps of bonding application more accurate.[6] The first, second, and third generations of bonding were not clinically applicable and could not be marketed. The fourth generation was the first one used in clinic and it is still considered as the gold standard due to its high-bond strength and durability.[7]

Fifth generation bonding agents are two-step systems in which primer and adhesive resin get mixed together and could be used following acid conditioning. Fifth generation is also called one-bottle system.

Seventh generation bonding agents such as Clearfil S3 Bond and I bond are self-etch systems, which contain acid, primer, and adhesive resin in one bottle.[8]

Various studies have claimed that self-etch systems have lower clinical retention compared to one bottles. This deduction literally put blame on the absence of separated etchant agent in self-etch systems, therefore we carried out this study to figure out the effect of adding an etchant material on clinical retention of seventh generation adhesive.

 Materials and Methods

This study was a prospective study, and it was in accordance with the declaration of Helsinki for human rights and has been approved by the ethical committee of Tabriz University of Medical Sciences with the registration number of IR.TBZMED.REC.1396.648. Data obtained from this study were analyzed by descriptive statistics measures and chi-square test via SPSS 17 software (SPSS Inc., 233 South Wacker Drive, 11th floor, Chicago, IL). P<0.05 considered statistically significant. [Table 1]{Table 1}

Ratio estimation formula was used to determine the sample size, and with regard to α = 0.05, 80% power and d = 0.4 the sample size was determined.

Inclusion criteria:

Participants should have had cooperation and acceptance for dental treatment and good oral hygiene.Patients with a pair of sound first permanent mandibular molars, bilaterally, which were qualified for fissure sealant therapy.Ages between 7 and 12 years.Teeth should have had acceptable situation for isolation with cotton roll.

Exclusion criteria:

Presence of any types of dental caries.Medically compromised patients.Tooth isolation impossibility.Lack of cooperation and acceptance from patients or their parents.Self-cleansing occlusal pits and fissures which did not need fissure sealant therapy.

After taking written consent from parents for each participant, sealant therapy was performed.

Treatment procedure:

After taking the benefit of cotton roll and high-volume suction, teeth were cleaned with an explorer or with dental bristle brush without polishing paste. Etching with 37% phosphoric acid (3M ESPE, St. Paul- USA) was performed for 15 seconds. The etched surface was washed for 15 seconds then tooth surface dried for 15 seconds with compressed air. At this step, the etched enamel had a chalky appearance indicating demineralization; otherwise etching should have been repeated. In case of saliva contamination, the tooth was re-isolated, washed, and dried and the etching step was repeated for 10 seconds. At this time, the cotton rolls got replaced. Successively on teeth in fifth generation bonding group, single bond 2 (3M ESPE, Pulp dent corporation, USA) applied on etched tooth surface and then cured for 20 seconds in compliance with factory instruction and in the seventh generation bonding group Clearfil S3 bond (Kurary Co Ltd, Osaka, Japan) was used and cured for 10 seconds. Then, Clinpro Sealant (3M ESPE St. Paul- USA) was utilized on teeth spreading all over the fissures and Cured for 20 seconds. Finally, the sealant was assessed for the presence of air bubbles and initial acceptance. Then occlusal adjustment and final polishing was done. All the abovementioned procedures have been done by a pediatric dentistry resident in Pediatric Dentistry Department of Tabriz University of Medical Science.

6- and 12- month follow-ups

Sealant retention was overhauled by a pediatric dentist who was blind to the study using oral explorer and mirror. Through sealants without caries considered as a successful treatment.


For the 6-month follow-up, 38 patients of 40 referred. The success rate for seventh generation adhesive with separate etching was 84.2,% and it was 76.3% for fifthth generation adhesive. The bar chart 1 shows the success and failure rate in both groups after 6 month.

The results of Fisher test showed that the difference between the two groups was not statistically significant at 6-month follow-up (df = 1, value = 0.748, P = 0.184).

At 12 month, two further patients did not refer for follow-up and remaining 36 patients were examined. The clinical success rate of seventh generation with separated etching was 36.1%, and the failure rate was 63.9/%; also, the clinical success rate of fifth generation was 52.8% and the failure rate was 47.2%. Chart 2 illustrates the clinical success and failure in both groups after 12 month.

According to Fisher test, there was not statically significant difference between two groups after 12 months (df = 1, value = 2.025, P = 0/155).


The considerable efficacy of fissure sealants in preventing occlusal caries is a widely held perception [9] and evidence-based researches recommend fissure sealant as an acceptable preventive strategy for dental caries.[10] ADA has two key recommendations regarding fissure sealants:Sealants are cut out for preventing and controlling caries especially in first permanent molars of children and adolescents compared to fluoride varnish or leaving these teeth untreated.Sealants can minimize the progress of occlusal carious lesions, which have not developed cavity.[11]

Various methods have been deployed for boosting sealant retention, including the air-abrasion with aluminum oxide, laser systems, and the use of adhesives before applying sealant.[5]

Nowadays, wide variety of researches have shown that prior conditioning of enamel using acid is requisite for sufficient bonding of the resin to the enamel,[3] as well as it gives rise to higher bond strength and shear strength in one-step self-etch adhesives.[12] Clinical evidences suggest that sealant therapy’s failure usually occurs in two phases, the first one is due to the poor sealant technique and moisture contamination, and the second one is due to wear of sealant under occlusal pressures. Regarding the highest failure rate, which occurs during first 6 months after sealant procedure, it seems that tooth selection and moisture control are the most momentous factors for sealant’s clinical success and it has been demonstrated that, sealants used in optimum conditions of moisture control will remain intact up to 2 years.[13]

Clearfil S3 Bond is a seventh generation bonding agent. Ideal features of seventh generation bonding agents are high-bond strength (20–30 MPa) to dentin, creating thin film thickness, being tolerant to the moist and dry environment as their most prominent feature and having fluoride-releasing potency. All-in-one self-etch systems (seventh generation) are not as acidic as the phosphoric acid used in etch and rinse adhesives. Lately mentioned feature has raised concerns about using all-in-one self-etch systems on intact enamel[14] because the prismless outermost layer of enamel may prevent an adequate penetration of self-etch adhesives into enamel and subsequently gives rise to creating weaker bond strength between enamel and resin.[15],[16] Nowadays, most researchers recommend using a separate etching step particularly on uncut enamel surface before exploiting self-etch adhesives to increase retention of bonding and prevention from marginal leakage.[17]

Under limitations of this study like strict sample size and single sampling location, we evaluated the clinical success rate of sealants over 6- and 12-month period between two groups, seventh generation adhesive with separated etchant and fifth generation bonding agent. It was done in split mouth manner to eliminate interfering factors and all procedures were performed by one person. Follow-ups have been done by a blinded examiner and analysis did not feature any statistically significant difference between the two groups in terms of clinical success rate and retention at 6- and 12-month follow-ups.

Varieties of studies have compared sealant’s retention when using Self-etch adhesives with etch and rinse systems.

In a study, which have been done by Su et al.[18] in 2015, the sealant retention was compared between self-etch and phosphoric acid systems. According to this study, sealant retention in one-step systems was significantly lower than etch and rinse method.[18]

In another clinical trial conducted by Aman et al.[19] in 2015, sealant’s retention was compared between Self Etch and Total Etch systems. In this research, total etch bonding featured a high amount of retention compared to self-etch adhesive.[19] In a study by Baubridge et al.[9] in 2006 and Karaman et al.[20] in 2013, the results depicted that higher retention could be achieved in fissure sealant when using etch and rinse adhesives rather than self-etch bonding agents.

In systematic reviews garnered by Bagherian and Sarraf Shiraz in 2016, it has been noted that in fissure sealant therapy, etchant conditioning was superior to other methods in terms of clinical success, as well as sealant retention was tremendously higher when using etch and rinse systems compared to self-etch adhesives.[21],[22]

All of above studies showed that clinical success of self-etch systems is less than etch and rinse systems.

In a randomized clinical trial conducted by Erbas et al.[23] in 2017, sealant’s retention was compared in three groups of adhesives: etch and rinse adhesive, self-etch adhesive, and self-etch adhesive, which previously got separated etchant agent. According to this study, sealant retention in etch and rinse group and self-etch adhesive with separated etchant was higher than other adhesive system. There was no statistically significant difference between the retention obtained from two above mentioned groups.[23]

The result of our study is in compliance with Erbas research. These clinical trials show that sealant retention increases after using self-etch adhesives in combination with additional etching agent. Adding etchant material increases the bond strength, shear strength, and sealant retention in self-etch adhesives.[12] All in all using self-etch bonding systems without including a separated etch step is not recommended, particularly in cases with enamel margins. As it is said before, this proposal originates from less effective modification of enamel prisms when using seventh generation bonding agents that lead to establishing a weaker bond between enamel and resin materials; however, more researches with larger sample size and researches, which consider more interfering factors such as caries development risk of parents or nutritional deficiency of child such as Ca and vitamin D, into inclusion criteria are needed. Furthermore, declaration of the exact cause of sealant failure could be more helpful for a scientific decision about either confirmation of applicability of seventh generation adhesives on enamel surface, without any fundamental change in their formula, or making an efficient change in seventh generation adhesives formula in order to obtain higher clinical success rate.


According to results of our study seventh generation adhesives applied following acid etch preparation, have similar clinical success rate and retention to fifth generation bonding agents in fissure sealant therapy.


This study was supported and funded by Tabriz University of Medical Science. We are also grateful to the parents and children who participated in this study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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