Nondestructive, in vitro quantification of crown margins

Area of Science:

• Dental materials science
• Prosthodontics
• Biomaterials engineering

Background:

• Accurate artificial crown fit is essential to prevent plaque accumulation and periodontal disease.
• Existing marginal fit assessment methods are often destructive or limited in scope.
• Marginal deficiencies in dental crowns increase the risk of oral health complications.

Purpose of the Study:

• To compare the in vitro marginal fit of four complete crown types on human premolar teeth.
• To evaluate the efficacy of nondestructive profilometry for assessing crown marginal fit.
• To determine if crown type or tooth surface morphology (grooved vs. ungrooved) influences marginal fit.

Main Methods:

• Four crown types were prepared: bonding alloy (BA), gold alloy (G), porcelain with chamfer (PC), and porcelain with shoulder (PS) finish lines.
• Profilometry was used to measure absolute marginal discrepancy (AMD) on grooved and ungrooved tooth surfaces.
• Measurements were taken on prepared teeth and on teeth with seated, un-cemented crowns.

Main Results:

• Significant differences in marginal fit were found between crown types for most parameters.
• Porcelain crowns (PC and PS) generally exhibited greater marginal discrepancies than alloy crowns (BA and G).
• Tooth surface morphology had a limited significant effect on marginal fit, except for vertical leading edge (LE) measurements.

Conclusions:

• Nondestructive profilometry provides an accurate method for evaluating absolute marginal fit of dental crowns.
• Marginal fit varied circumferentially, highlighting the limitations of subjective clinical assessments.
• Crown type significantly impacts marginal fit, with implications for material selection and fabrication processes.