New material perspective for endocrown restorations: effects on mechanical performance and fracture behavior

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials Engineering

Background:

• Endocrowns are a viable option for restoring severely damaged nonvital teeth.
• Evaluating the mechanical performance and fracture behavior of different restorative materials used in endocrowns is crucial for clinical success.

Purpose of the Study:

• To investigate the mechanical performance and fracture behavior of endocrown restorations fabricated with distinct restorative materials.
• To compare the fracture modes of endocrowns made from conventional composite, bulk fill composite, and lithium disilicate.

Main Methods:

• 42 endodontically treated molars were restored with endocrowns made from conventional composite (Filtek™ Z350 XT), bulk fill composite, composite with resin adhesives (SBMP/SBU), or lithium disilicate (IPS e.max).
• Unprepared sound teeth served as negative controls.
• Restorations underwent fatigue and fracture testing to determine load-to-fracture and work-of-fracture values.

Main Results:

• All endocrowns demonstrated adequate mechanical performance, with no fractures or debonding during fatigue testing.
• Load-to-fracture and work-of-fracture values were comparable across all tested restorative materials.
• Endocrowns using composite with Scotchbond™ Multipurpose Adhesive (SBMP) exhibited less severe fractures compared to other composite groups. IPS e.max endocrowns showed more aggressive failures, including root fractures.

Conclusions:

• The endocrown technique is effective for restoring severely damaged nonvital teeth.
• Composite endocrowns utilizing resin adhesives or bulk fill materials may lead to more favorable fracture patterns, suggesting new material options.
• Material selection for endocrowns can influence fracture behavior, with potential implications for long-term prognosis.