Evaluation of CAD/CAM and PFM Crowns Done by the Undergraduates

Objectives:

This study compared treatment outcomes with respect to restoration survival and periodontal health of all-ceramic CAD/CAM (Cerec 3D) crowns and porcelain fused to metal (PFM) crowns done by undergraduate students at The University of Queensland, School of Dentistry.

Methods:

Patients who received a PFM and/or all-ceramic crown from final year Dental Students were included in this study. Clinical measurements and assessments recorded the type and position of the crown; duration since cementation; tooth vitality; position of margins; failures; presence of plaque; bleeding on probing (BOP) and patient oral hygiene. Statistical analysis was performed using logistic regression analysis to evaluate model variables (type of crown, duration, position, oral hygiene) and responses (vitality, BOP, plaque, margins). Individual chi-square tests of independence were conducted with the significance level at 5%.

Results:

There were 42 patients and 74 (43 all-ceramic and 31 PFM) crowns in the analysis. The mean duration for both groups was 77.15 weeks. Only one all-ceramic crown fractured at 103 weeks following cementation. The all-ceramic crowns had a significantly greater level of supra-gingival margins (p=0.001), but no significant difference was noted between presence of plaque and type and position of crowns. Crowns with supra-gingival margins were three times more likely to have plaque than crowns with equi-gingival margins (p=0.008). There was no significant association between BOP and type and position of the crowns and oral hygiene. Sub-gingival margins were eight times more likely to have BOP than equi-gingival margins (p=0.009).

Conclusions:

This study indicates that all-ceramic CAD/CAM (Cerec 3D) crowns placed by appropriately trained undergraduate students perform similarly to PFM crowns and can be recommended as an aesthetic treatment option. The superior aesthetics of all-ceramic crowns allows equi-gingival margins, which results in less plaque accumulation and therefore less risk to periodontal health.