Development of a Compact Chairside Ultrasonic Post-Etch Cleansing Unit for Hydrofluoric Acid-Etched Lithium Disilicate: Design and Fabrication

Abstract

Introduction: Reliable adhesive bonding to lithium disilicate depends not only on hydrofluoric acid etching, but also on effective removal of post-etch reaction residues before silanization and resin cementation. Although ultrasonic cleansing has been investigated as a useful adjunct to postetch cleaning, chairside use remains poorly standardized because conventional laboratory ultrasonic baths are not specifically designed for this step.

Objectives: To describe the design and fabrication of a compact chairside ultrasonic post-etch cleansing unit intended to standardize cleansing of hydrofluoric acid-etched lithium disilicate.

Methods A technical development workflow was undertaken beginning with identification of the clinical and laboratory requirements for a dedicated post-etch cleansing device. The unit was conceptualized as a compact single-chamber system that could be used chairside after hydrofluoric acid etching and phosphoric acid cleansing. Computer-aided design was used to develop the main body, lid, and internal perforated specimen cage. The final design incorporated a polycarbonate external housing with a metallic inner cleansing assembly and a removable perforated cage to permit solution access, specimen containment, and easy retrieval. Based on the finalized design drawings, the main body measured approximately 173 × 78 × 83 mm, with an internal cage measuring 151 × 48 × 73 mm. The lid was designed to provide enclosure during cleansing while preserving ease of access and operability. Design priorities included compactness, structural stability, chemical compatibility, chairside handling, and standardization of specimen cleansing.

Results: The final prototype was successfully developed as a compact single-chamber chairside ultrasonic cleansing unit with three principal components: main body, perforated internal cage, and lid assembly. The design permitted organized placement and retrieval of etched specimens, adequate exposure of the specimens to cleansing solution, and a practical chairside footprint. The perforated cage architecture allowed fluid communication during ultrasonic activation while minimizing specimen displacement. The completed prototype was suitable for incorporation into the experimental workflow for post-etch cleansing of lithium disilicate specimens.

Conclusions: A novel compact chairside ultrasonic post-etch cleansing unit was successfully designed and fabricated for standardized cleansing of hydrofluoric acid-etched lithium disilicate. The prototype offers a practical platform for controlled post-etch cleansing and may improve procedural standardization in laboratory investigations and future clinical translation.