Adhesive protocol for anterior composites: enamel, dentin and selective etching

Which strategy for which surface?

The decision in this article rests on one question: how much of the restoration bonds to enamel and how much to dentin? In diastema closure, direct veneers and Class IV restorations with margins in enamel, most of the bond is to enamel; when a wide dentin surface is exposed, the dentin protocol carries more of the decision. The choice also depends on the adhesive system used.

In a meta-analysis of direct anterior restorations (21 clinical trials), the estimated median success after 10 years, defined as restorations not replaced, was 95% for Class III and 90% for Class IV restorations.⁶ In the same analysis, enamel that was acid-etched without a bonding agent showed marginal staining and detectable margins more often; these findings were less frequent when enamel etching was combined with a bonding agent or a total-etch technique, and self-etch systems fell in between.⁶ The German S3 guideline also recommends phosphoric acid etching to improve restoration quality.¹

In a meta-analysis of 15 randomised trials, universal adhesives showed no statistically significant difference from conventional etch-and-rinse and self-etch adhesives in retention, marginal discolouration and postoperative sensitivity, regardless of application mode (follow-up 6 months to 4 years).⁷ Meta-analytic findings on the effect of the application mode do not all point the same way. In non-carious cervical lesions, the risk of retention loss at 12 and 18 to 24 months was higher in self-etch mode than in etch-and-rinse mode (moderate certainty).⁸ Compared with self-etch, selective enamel etching was associated with lower odds of retention loss at 18 to 24 months (OR 0.31; low certainty).² An updated meta-analysis comparing total-etch and self-etch strategies of universal adhesives (cervical lesions, 13 studies), however, found no significant difference in retention, marginal adaptation, marginal discolouration, secondary caries or postoperative sensitivity at 18, 24 and 36 months; the authors reported strongly suspected publication bias in the 18-month retention data under FDI criteria.¹⁵

A network meta-analysis of 16 randomised trials (674 patients, 2816 restorations) found more marginal discolouration at 12, 24 and 36 months with self-etch used without selective enamel etching than with etch-and-rinse. Selective enamel etching and etch-and-rinse were similar for marginal discolouration, marginal adaptation and retention.³ The abstract of this network meta-analysis does not state the lesion type; most randomised trials of adhesive strategies were run in cervical lesions; how far it applies to direct veneers and diastema closure has not been tested directly. A 2026 network meta-analysis of 74 randomised trials in cervical lesions also found the most consistent clinical advantages for strategies combining selective enamel etching or etch-and-rinse with universal adhesives and nanocomposites.⁹

Laboratory findings point the same way; in a meta-analysis of 59 studies, enamel bond strength of universal adhesives rose with the etch-and-rinse approach, and mild universal adhesives remained stable after ageing in both strategies.¹⁰

Findings on postoperative sensitivity point in different directions. One meta-analysis linked self-etch mode to less sensitivity (moderate certainty); the network meta-analysis found no difference among the three strategies.^{3, 8} A practical division follows. When most of the bonded surface is enamel, prepare the enamel with phosphoric acid. When a wide dentin surface is exposed, leaving the dentin in self-etch mode and selectively etching the enamel is one option consistent with both the retention and the sensitivity findings. This is an inference from cervical-lesion data: in trials comparing selective enamel etching with self-etch, no difference other than retention reached significance (very low certainty).^{2, 8}

Step-by-step protocol

1. Isolate with rubber dam or another isolation method that can keep saliva and blood out throughout the procedure. In a Cochrane review, rubber dam was associated with fewer failures than cotton rolls for cervical composites at six months (low certainty); at 12 and 18 months the evidence is very uncertain (one study, very low certainty); in a meta-analysis of cervical restorations, retention was higher with rubber dam in teeth whose dentin had been roughened.^{11, 12}
2. In Class IV, assess whether the enamel margin needs a bevel. In the anterior meta-analysis, bevelling was associated with less deterioration of anatomical form; it was not shown to reduce marginal staining.⁶ In cervical lesions, bevelling did not affect retention.¹²
3. Choose the adhesive system and its application mode before you start. Apply phosphoric acid to enamel only (selective enamel etching), or to enamel and dentin with an etch-and-rinse system. Follow the manufacturer's instructions for etching time and for the application sequence, including any separate primer step.^{1, 2}
4. Rinse and dry. Follow the adhesive manufacturer's instructions for dentin moisture. In a meta-analysis of five randomised trials in non-carious cervical lesions restored with etch-and-rinse bonding, retention and sensitivity did not differ significantly between dry and moist dentin (moderate certainty); this does not show that moisture is unimportant for every adhesive.⁴
5. Apply the adhesive following its instructions. In a laboratory meta-analysis, active (scrubbing) application raised bond strength to dentin and unetched enamel; on enamel prepared with phosphoric acid, passive application of a universal adhesive gave higher values. These are bond-strength findings; they do not show better clinical retention.¹³
6. Evaporate the solvent and light-cure the adhesive as the manufacturer instructs.
7. Place the composite and light-cure it according to the material's instructions, checking that the light reaches the whole restoration; the S3 guideline stresses the decisive role of light polymerisation.¹
8. If saliva or blood contaminates the field, stop and re-establish isolation, then choose the decontamination step according to the surface and the bonding stage reached. In a systematic review of laboratory studies on dentin, with contamination at different stages of bonding, water-spray rinsing and reapplying the bonding system could reverse the bond loss; cleaning blood with a haemostatic agent is not recommended.⁵
9. Finish and polish; the S3 guideline recommends polishing for surface quality.¹ Details are in the finishing and polishing article.

Common errors and fixes

Level of evidence

What is known

Universal adhesives showed no significant difference from conventional systems in clinical outcomes. Preparing enamel with phosphoric acid makes retention more predictable and reduces the marginal discolouration seen more often with self-etch use without selective etching. These findings come from meta-analyses of randomised trials, mostly in cervical lesions, with certainty mostly low to moderate.^{2, 3, 7, 8} In cervical-lesion trials with etch-and-rinse bonding, dentin moisture did not significantly change retention or sensitivity (moderate certainty).⁴

What is not known

Most randomised trials comparing adhesive strategies were run in non-carious cervical lesions; comparative evidence specific to diastema closure and direct veneers is limited. Of the 21 trials in the anterior meta-analysis, 18 started before 2001.⁶ A 2014 systematic review reported that selective enamel etching did not significantly change the retention of self-etch adhesives; newer meta-analyses focused on universal adhesives favour selective etching. An updated meta-analysis comparing total-etch and self-etch strategies of universal adhesives found no significant difference; results of mode comparisons do not point the same way across reviews.^{2, 14, 15} The findings on application motion and contamination come from laboratory studies.^{5, 13}

At the chair

• How much of the bonded surface is enamel, and how much dentin?
• Will the enamel be prepared with phosphoric acid: selective or total etch?
• Is the isolation method decided?
• Are the adhesive system, its mode and its application sequence decided?
• Does the team know to stop, re-isolate and decontaminate by stage after saliva or blood contact?
• In Class IV, has the need for an enamel bevel been assessed?
• Do etching, solvent evaporation and curing of the adhesive and composite follow the manufacturer's instructions?

References

1. Sekundo C, Frese C, Frankenberger R, Haak R, Braun A, Krämer N, et al. Direct Composite Restorations on Permanent Teeth in the Anterior and Posterior Region - An Evidence-Based Clinical Practice Guideline - Part 2: Recommendations for Composite Processing. J Adhes Dent. 2024;26:201-212. PMID: 39286911 · DOI: 10.3290/j.jad.b5749192
2. Josic U, Mazzitelli C, Maravic T, Radovic I, Jacimovic J, Mancuso E, et al. The influence of selective enamel etch and self-etch mode of universal adhesives' application on clinical behavior of composite restorations placed on non-carious cervical lesions: A systematic review and meta-analysis. Dent Mater. 2022;38(3):472-488. PMID: 35151466 · DOI: 10.1016/j.dental.2022.01.002
3. Ma KS, Wang LT, Blatz MB. Efficacy of adhesive strategies for restorative dentistry: A systematic review and network meta-analysis of double-blind randomized controlled trials over 12 months of follow-up. J Prosthodont Res. 2023;67(1):35-44. PMID: 35691823 · DOI: 10.2186/jpr.JPR_D_21_00279
4. Forville H, Wendlinger M, Cochinski GD, Favoreto MW, Wambier LM, Chibinski AC, et al. Re-evaluating the role of moist dentin of adhesive systems used in the etch-and-rinse bonding strategy. A systematic review and meta-analysis. J Dent. 2025;152:105495. PMID: 39613137 · DOI: 10.1016/j.jdent.2024.105495
5. Bourgi R, Cuevas-Suarez CE, Devoto W, Monjarás-Ávila AJ, Monteiro P, Kharma K, et al. Effect of contamination and decontamination methods on the bond strength of adhesive systems to dentin: A systematic review. J Esthet Restor Dent. 2023;35(8):1218-1238. PMID: 37395344 · DOI: 10.1111/jerd.13078
6. Heintze SD, Rousson V, Hickel R. Clinical effectiveness of direct anterior restorations--a meta-analysis. Dent Mater. 2015;31(5):481-95. PMID: 25773188 · DOI: 10.1016/j.dental.2015.01.015
7. Polesso Patias M, Fernandes-E-Silva P, Carreño NLV, Lund RG, Piva E, da Silva AF, et al. Comparative clinical performance of universal adhesives versus etch-and-rinse and self-etch adhesives: a meta-analysis. Clin Oral Investig. 2025;29(7):352. PMID: 40560221 · DOI: 10.1007/s00784-025-06427-w
8. Josic U, Maravic T, Mazzitelli C, Radovic I, Jacimovic J, Del Bianco F, et al. Is clinical behavior of composite restorations placed in non-carious cervical lesions influenced by the application mode of universal adhesives? A systematic review and meta-analysis. Dent Mater. 2021;37(11):e503-e521. PMID: 34481667 · DOI: 10.1016/j.dental.2021.08.017
9. Chaple Gil AM, Pereda Vázquez L, Santiesteban Velázquez M, Menéndez JJ. Comparison of Adhesive Strategies with Different Etching Approaches on the Clinical Performance of Restorations in Non-Carious Cervical Lesions: A Systematic Review and Network Meta-Analysis. J Funct Biomater. 2026;17(4):160. PMID: 42042267 · DOI: 10.3390/jfb17040160
10. Cuevas-Suárez CE, da Rosa WLO, Lund RG, da Silva AF, Piva E. Bonding Performance of Universal Adhesives: An Updated Systematic Review and Meta-Analysis. J Adhes Dent. 2019;21(1):7-26. PMID: 30799468 · DOI: 10.3290/j.jad.a41975
11. Miao C, Yang X, Wong MC, Zou J, Zhou X, Li C, et al. Rubber dam isolation for restorative treatment in dental patients. Cochrane Database Syst Rev. 2021;5(5):CD009858. PMID: 33998662 · DOI: 10.1002/14651858.CD009858.pub3
12. Mahn E, Rousson V, Heintze S. Meta-Analysis of the Influence of Bonding Parameters on the Clinical Outcome of Tooth-colored Cervical Restorations. J Adhes Dent. 2015;17(5):391-403. PMID: 26525003 · DOI: 10.3290/j.jad.a35008
13. Carvalho GLM, Moreira PM, Carneiro BT, Suzuki TYU, Lanza MDS, Alvim HH, et al. Impact of active vs. passive application of dental adhesives on bond strength to dentin and enamel: A systematic review and meta-analysis of in vitro studies. Jpn Dent Sci Rev. 2025;61:90-102. PMID: 40416390 · DOI: 10.1016/j.jdsr.2025.04.001
14. Peumans M, De Munck J, Mine A, Van Meerbeek B. Clinical effectiveness of contemporary adhesives for the restoration of non-carious cervical lesions. A systematic review. Dent Mater. 2014;30(10):1089-103. PMID: 25091726 · DOI: 10.1016/j.dental.2014.07.007
15. Doshi K, Nivedhitha MS, Solete P, S DPA, Balasubramaniam A, Jacob B, et al. Effect of adhesive strategy of universal adhesives in noncarious cervical lesions - an updated systematic review and meta-analysis. BDJ Open. 2023;9(1):6. PMID: 36781841 · DOI: 10.1038/s41405-022-00124-6

Methods note

Sources were searched in PubMed (NCBI E-utilities) on 5 November 2026. The search covered application modes of universal adhesives, etch-and-rinse versus self-etch, selective enamel etching, dentin moisture, application motion, contamination, bevelling and the clinical performance of anterior composites. Systematic reviews, meta-analyses, randomised trials and guidelines were given priority. Author, title, journal, year and DOI of every source were checked against its PubMed record; findings were taken from abstracts only, and full texts were not read. No product or brand names are given. This is not a systematic review; it was prepared from one database by one reader.

Author: Dr. Ferit Çiftçi · Dentist · Author page · Last updated: 5 November 2026

This text is not patient information. Treatment decisions are made after an examination and for each person individually.

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