Effect of Resin Coating on Nanoleakage and Shear Bond Strength of Universal Adhesives: Comparison with a Contemporary Two-Step Universal Adhesive- An In Vitro Study

Universal adhesive; G2 Bond Universal; Resin coating; Nanoleakage; Shear bond strength.

Dr Aarya Bose1,
Post Graduate Student,
Department of Conservative Dentistry and
Endodontics, Royal Dental College, Chalissery,
Palakkad, Kerala , India
Email ID: aaryapgt@gmail.com
ORCID: 0009000653685535

Dr Jojo Kottoor2*,
Professor, Department of
Conservative Dentistry and Endodontics, Royal
Dental College, Chalissery, Palakkad, Kerala,
India
Email ID: drkottooran@gmail.com
ORCID ID: 0000000344790238

Dr Mohammed Sagir V M3,
Professor and Head of the Department,
Department of Conservative
Dentistry and Endodontics, Royal Dental
College, Chalissery, Palakkad, Kerala, India
Email ID: sagirdr@gmail.com
ORCID ID: 0000000174950648

Dr Jisna C Manjila4,
Assistant Professor,
Department of Conservative Dentistry and
Endodontics, Royal Dental College, Chalissery,
Palakkad, Kerala, India
Email ID: jisna7291@gmail.com
ORCID ID: 0009000644310440

Dr Adarsh Roshan S5,
Senior Lecturer,
Department of Conservative Dentistry and
Endodontics, Royal Dental College, Chalissery,
Palakkad Kerala, India
Email ID: dradarshroshan@gmail.com
ORCID ID: 0009000416696847

Dr Amjad Mohamed K6,
Assistant Professor,
Department of Conservative Dentistry and
Endodontics, Royal Dental College, Chalissery,
Palakkad, Kerala, India
Email ID: jidoos95@gmail.com
ORCID ID: 000900036169160X

Received:16-06-2026
Revised:21-07-2026
Accepted: 25-07-2026

European Journal of Prosthodontics and Restorative Dentistry (2026) 34(7s), 459–464

Effect of Resin Coating on Nanoleakage and Shear Bond Strength of Universal Adhesives: Comparison with a Contemporary Two-Step Universal Adhesive- An In Vitro Study

Objective: Nanoleakage at the resin–dentin interface adversely affects the longevity of adhesive restorations. Contemporary two-step universal adhesives and resin-coating techniques have been introduced to improve interfacial sealing ability. The objective of the study was to evaluate the effect of resin coating on nanoleakage and shear bond strength of a universal adhesive and compare it with a contemporary two-step universal adhesive. Methods: Eighty extracted human premolars were randomly divided into four groups (n=20): Group A—G2 Bond Universal; Group B—G-Premio Bond; Group C—G-Premio Bond with resin coating using G-aenial Universal Flo; and Group D—control. Composite restorations were placed using G-aenial Posterior composite. Half of the specimens were evaluated for nanoleakage using Confocal Laser Scanning Microscopy, while the remaining specimens underwent shear bond strength testing using a universal testing machine. Data were analyzed using one-way ANOVA and Bonferroni post hoc tests (P < 0.05). Results: Group A exhibited the lowest nanoleakage, whereas the control group showed the highest. Resin coating significantly reduced nanoleakage compared with the uncoated single-step adhesive (P=0.001). The highest mean shear bond strength was observed in Group A (54.85 ± 10.19 MPa), followed by Group C (44.22 ± 12.48 MPa), Group B (42.11 ± 12.50 MPa), and Group D (26.94 ± 1.20 MPa). Group A demonstrated significantly higher bond strength than the control group (P=0.0001). Conclusion: The two-step universal adhesive demonstrated superior interfacial sealing ability. Resin coating significantly improved the performance of the single-step universal adhesive and may serve as a simple strategy to enhance restoration longevity.

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