A novel method to obtain microtensile specimens minimizing cut flaws

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Conventional cutting methods for microtensile specimens can induce stress and cracks, particularly in brittle dental enamel.
• This damage can compromise the accuracy of bond strength testing results.
• Alternative cutting techniques are needed to improve specimen integrity.

Purpose of the Study:

• To compare the efficacy of diamond wire cutting versus conventional diamond disc cutting in preparing microtensile specimens.
• To evaluate the impact of cutting method and specimen shape on bond strength, considering premature failures.
• To assess the incidence of cracks and defects using Scanning Electron Microscopy (SEM).

Main Methods:

• Forty human molars were prepared, bonded, and sectioned using either a diamond disc or a diamond wire.
• Specimens were prepared in slab and stick shapes, with slabs further shaped into hourglass forms.
• SEM analysis and microtensile testing were performed, with results analyzed using three-way ANOVA, accounting for premature failures.

Main Results:

• Diamond wire cutting resulted in fewer cracks and defects compared to diamond discs, especially in enamel.
• On dentin, excluding premature failures significantly increased bond strength values.
• On enamel, cutting equipment, specimen shape, and inclusion/exclusion of premature failures all significantly affected bond strength.

Conclusions:

• Diamond wire cutting is a superior method for preparing microtensile specimens, minimizing structural damage.
• Accurate assessment of bond strength requires careful consideration of premature failures, particularly in enamel.
• The findings highlight the importance of appropriate specimen preparation techniques in adhesive dentistry research.