Dental crowns on a chessboard

Crown Retention Face-Off: Which Silica Coating Reigns Supreme?

Lena Voss in Health & Wellness December 2025 • 4 min read.

"A Deep Dive into Y-TZP Crown Retention Methods"

For anyone seeking a durable and aesthetically pleasing smile, dental crowns have become a popular solution. Among the array of crown materials available, yttrium oxide-stabilized zirconia polycrystal (Y-TZP) stands out for its exceptional strength and biocompatibility. However, even the most robust crown is only as good as its retention – how well it stays bonded to the underlying tooth structure.

The challenge lies in the inherent properties of Y-TZP, which make it difficult to achieve a strong and lasting bond with traditional dental cements. Unlike glass ceramics, Y-TZP lacks a silica phase, rendering hydrofluoric acid etching – a common technique for enhancing bond strength – ineffective. This has spurred the development of various surface treatments aimed at improving the adhesion of resin cements to Y-TZP crowns.

Among these surface treatments, silica coating methods have emerged as promising contenders. By depositing a layer of silica on the intaglio surface (the inner surface that contacts the tooth), these methods aim to create a more receptive surface for bonding. But with a variety of silica coating techniques available, which one offers the best retentive strength?

Decoding the Silica Coating Showdown: Methods Unveiled

A recent study published in Operative Dentistry sought to answer this very question by comparing the retentive strength of Y-TZP crowns treated with different silica coating methods. Researchers investigated five distinct approaches:

Each method aims to modify the intaglio surface of the Y-TZP crown, creating a more favorable bonding environment for resin cements.

TBS (Tribochemical Silica Coating): This involves air-abrasion with silica-coated alumina particles, essentially blasting the surface with tiny particles to create a rough, silica-rich layer.
GHF1 (Glaze + HF for 1 minute): A thin layer of porcelain glaze is applied, followed by etching with hydrofluoric acid for just 1 minute.
GHF5 (Glaze + HF for 5 minutes): The same glaze is applied, but the hydrofluoric acid etching is extended to 5 minutes.
GHF15 (Glaze + HF for 15 minutes): Extending the etching time even further to 15 minutes.
NANO (Silica Nanofilm Deposition): A thin film of silica is applied using magnetron sputtering, a high-tech process that creates a uniform and chemically reactive layer.

The study meticulously prepared 100 simplified full-crown preparations from fiber-reinforced polymer material. One hundred Y-TZP crowns with occlusal retentions were milled. Then, each crown underwent one of the silica coating treatments, cemented to the prepared teeth using resin cement, and subjected to rigorous testing. After thermocycling to simulate the effects of temperature changes in the mouth, the crowns were subjected to a retentive strength test until failure (decementation). The data were then analyzed to determine which method yielded the strongest bond.

The Winner's Circle: Key Takeaways and Clinical Implications

So, which silica coating method emerged as the champion? The study revealed that tribochemical silica coating (TBS) and silica nanofilm deposition (NANO) yielded the highest retentive strength values. These methods outperformed the glaze-and-HF etching techniques, suggesting that they provide a more effective means of enhancing the bond between Y-TZP crowns and resin cements. The findings underscore the importance of selecting appropriate surface treatments to ensure the long-term success of Y-TZP crown restorations. While TBS offers a reliable and relatively simple approach, NANO presents a high-tech alternative with the potential for precise control over the silica layer. As the field of dental materials continues to evolve, further research will undoubtedly refine these techniques and pave the way for even stronger and more durable crown restorations.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.2341/16-090-l, Alternate LINK

Title: Retentive Strength Of Y-Tzp Crowns: Comparison Of Different Silica Coating Methods On The Intaglio Surfaces

Subject: General Dentistry

Journal: Operative Dentistry

Publisher: Operative Dentistry

Authors: Vf Wandscher, C Prochnow, Mp Rippe, Ls Dorneles, Gl Callegari, P Baldissara, R Scotti, Lf Valandro

Published: 2017-09-01

Everything You Need To Know

What is Y-TZP and why is it used for dental crowns?

Yttrium oxide-stabilized zirconia polycrystal, often called Y-TZP, is a popular material for dental crowns because of its strength and biocompatibility. Its significance lies in offering patients a durable and aesthetically pleasing solution for damaged or missing teeth. However, Y-TZP's inherent properties make it difficult to bond to dental cements, requiring specific surface treatments to ensure strong retention.

Why are silica coating methods needed for Y-TZP crowns?

Silica coating methods are surface treatments applied to the intaglio surface of Y-TZP crowns to improve their bonding to resin cements. This is important because Y-TZP lacks a silica phase, making traditional etching techniques ineffective. These coatings create a silica-rich layer that enhances adhesion, ensuring the crown stays securely bonded to the tooth. Without these methods, Y-TZP crowns may not achieve adequate retention, leading to potential failures.

What is tribochemical silica coating (TBS) and why is it important?

Tribochemical silica coating, or TBS, involves air-abrasion with silica-coated alumina particles to create a rough, silica-rich layer on the Y-TZP crown. Its importance comes from its ability to significantly increase the retentive strength of the crown. This method is a relatively simple and reliable way to enhance bonding, making it a valuable tool in ensuring the long-term success of Y-TZP crown restorations. The impact of TBS is that it creates a mechanical bond for the resin cement to adhere to.

What is silica nanofilm deposition (NANO) and what are the benefits?

Silica nanofilm deposition, or NANO, is a high-tech method that applies a thin film of silica using magnetron sputtering. This creates a uniform and chemically reactive layer. Its significance lies in offering precise control over the silica layer, potentially leading to superior bond strength. NANO presents an advanced alternative to other methods like TBS, suggesting a future direction for even stronger and more durable crown restorations. The uniformity of the silica layer due to the NANO process provides a more consistent bonding surface.

What silica coating methods were compared in the study?

The study compared five different silica coating methods: TBS (Tribochemical Silica Coating), GHF1 (Glaze + HF for 1 minute), GHF5 (Glaze + HF for 5 minutes), GHF15 (Glaze + HF for 15 minutes), and NANO (Silica Nanofilm Deposition). Understanding the differences between these methods is crucial for dental professionals in selecting the most effective treatment for Y-TZP crowns. The goal of the study was to determine which method provided the best retentive strength, ultimately informing clinical practices.