Beyond the Smear Layer: Rethinking Particle Microabrasion in Adhesive Dentistry

By Dr Andrew See. Aesthetic Dentist and Educator, Founder of Dental Mastery Academy.

BDS Hons (Syd), FRACDS, MSc(Lond), PGDipDentImplantology, FCGDENT(UK), FICOI, MFDS RCSEng

Why bother microabrading dentine at all? It’s a question worth asking in today’s adhesive dentistry landscape—especially when modern bonding agents already perform reliably well. For many clinicians, especially those working in high-volume practices, the extra step may seem like an unnecessary addition to an already busy day. But for those striving for consistently stronger, longer-lasting bonds especially on dentine— particle microabrasion deserves renewed attention.

When I was in dental school and when I was a new graduate, not once did I see a microetcher used. And yet, our restorations generally held up well. Fast forward to today with the advent of modern preparation techniques that have zero retention and resistance form such as overlays and veneers, the challenge increases to obtain optimal bond strengths.

Let’s be honest: bonding to enamel is relatively predictable and simple. But bonding to dentine—especially when it’s contaminated or structurally compromised—is another story.

Scroll down to read the article featured in Australasian Dentist Magazine, August 2025 Edition.

Why Microetching Matters

Particle microabrasion in essence, it roughens and cleans the surface, increasing surface area and facilitating better micromechanical retention. This becomes especially valuable in restorative situations where we remove provisional restorations. In these situations we are typically dealing with:

• Residual temporary cement
• Biofilm and salivary proteins
• Contamination from provisional material or blood

Despite meticulous rinsing and scaling, these contaminants remain. A study by Erkut et al. (2014, J Prosthet Dent) confirmed that temporary cement remnants and biological debris significantly reduce bond strength. Among various surface-cleaning methods tested, particle microabrasion clearly outperformed others—producing the highest bond strengths and a surface texture that facilitated better adhesive penetration.

Interestingly, the microabrasion group in that study also demonstrated a failure mode shift—away from adhesive failures toward cohesive ones. Clinically, this implies fewer instances where restorations debond with no cement left on the tooth, which many of us have frustratingly encountered.

When and Where to Use It

Microabrasion excels in specific scenarios:

• Post-provisional clean-up for indirect restorations
• Compromised dentine: sclerotic, cracked, or reparative surfaces
• Cases involving Immediate Dentine Sealing (IDS)
• Chairside CAD/CAM workflows, where contamination may occur during the manufacturing process of the restoration

Navigating the Nuance

There’s ongoing debate about whether microabrasion benefits all adhesive systems. Some evidence suggests it complements self-etching systems by thinning the smear layer and exposing reactive dentine. Other studies raise questions about how certain universal adhesives respond.

The evidence suggests that if you are using a self-etching bonding agent, using microabrasion on the dentine will help you increase bond strength by removing and thinning the smear layer. This allows the bonding agent to interact directly with the denting and not just the smear layer and hence increases the bond strength.

Ouchi et al. in 2020 suggested that bond strengths when using universal adhesives are adversely affected when using microabrasion. They found reduced bond strength due to smear layer compaction. However, meta-analyses (Lima et al., 2021, Oper Dent) have shown that—when done correctly—it enhances rather than harms the adhesive interface.

Particle Size

The question then arises about what size particles to use? Lima et al recommended using Aluminium oxide particles that are larger than 30 µm at a pressure of 5+ bars, which has shown to improve bond strength without over-abrading. For most restorative applications, 50 µm is optimal. 

A Mindset for Excellence

In the real world—many dental practices are fast-paced environments where survival, not innovation, is the priority. You’re booked solid with back to back patients, barely have time to hydrate, and making clinical refinements is the last thing on your mind. But if you're reading this in Australasian Dentist, chances are you're someone striving for more.

For those of us committed to elevating our aesthetic and restorative results, microabrasion represents a simple, cost-effective enhancement to your workflow that pays has been shown to enhance long-term outcomes.

Want to Go Deeper?

If this topic resonated with you, it’s just the beginning. We explore this—and much more—in my once-a-year 8-week program: Mastering Porcelain Veneers. This course isn’t just about veneers; it’s about achieving predictable aesthetic outcomes in everyday practice using advanced adhesive protocols, smart material selection, and workflow mastery.

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