Internal Adaptation of Composite Fillings Made Using Universal Adhesives-A Micro-Computed Tomography Analysis

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials Engineering

Background:

• Universal adhesives are increasingly used in composite restorations.
• Understanding marginal integrity is crucial for long-term restoration success.
• Micro-computed tomography (µCT) offers detailed analysis of tooth-filling interfaces.

Purpose of the Study:

• To compare the internal tooth-filling interface integrity of composite fillings bonded with universal adhesives.
• To evaluate the influence of etch-and-rinse versus self-etch application modes.
• To assess the impact of thermomechanical loading and aging on interface quality.

Main Methods:

• Sixty class V cavities were restored using six different universal adhesive systems (Peak Universal, Adhese Universal) and controls (OptiBond FL, Clearfil SE).
• Adhesives were applied using either etch-and-rinse or self-etch techniques.
• Restorations underwent thermomechanical loading and four-year water storage.
• Micro-computed tomography (µCT) was used to quantify gap volumes (GV) relative to filling volume (FV) and cavity volume (CV), and internal (IGV) versus external gap volumes (EGV).

Main Results:

• Adhese Universal exhibited significantly lower gap-to-filling and gap-to-cavity volume ratios across both application modes compared to Peak Universal and control groups.
• No significant differences in internal versus external gap volumes were observed for Adhese Universal or Peak Universal groups.
• Significant differences between external and internal gap volumes were only noted in the control groups, suggesting better marginal adaptation with universal adhesives.

Conclusions:

• Adhese Universal demonstrates superior marginal integrity at the internal tooth-filling interface compared to Peak Universal and gold standard controls.
• The choice of universal adhesive material and its application technique (etch-and-rinse vs. self-etch) are critical factors influencing internal gap formation.
• Long-term stability and reduced gap formation highlight the potential of universal adhesives in durable composite restorations.