A Comparison of the Effect of Zirconia Crown on Periodontal Tissues: A Nonrandomized Clinical Trial

Background: Dental crowns are effective on the gingival tissue around the teeth. However, using zirconia as crowns due to the method and type of material can effectively improve this effect. Methods: This is a pre-post clinical trial conducted on 35 teeth with metal-ceramic crowns and 35 teeth with zirconia crowns. Teeth were prepared for fabricating metal-ceramic and zirconia crowns. Plaque index (PI), modified gingival index (MGI), pocket probing depth (PPD), papilla bleeding index (PBI), and gingival level (GL) were measured before and six months after getting the dental crown. The data were analyzed using the Mann–Whitney test. Results: In both groups, the GL remained the same after six months of crown placement (P 0.05). In the metal-ceramic group, the PI decreased significantly (P=0.000), but MGI and PBI significantly increased (P=0.000 and P=0.000, respectively) six months after crown placement. Based on the results, PPD increased significantly only on the midlingual surface (P=0.02). The PI significantly decreased in the zirconia group (P=0.000). Nevertheless, PPD represented no change (P 0.050). The comparison between the two groups six months after crown placement indicated that the PI, MGI, and PBI were significantly higher in the metal-ceramic group (P=0.010, P=0.011, and P=0.044, respectively). The metal-ceramic group showed a significantly greater increase in PPD on the midlingual surface (P=0.043). Conclusion: Both crown types on teeth could significantly increase the incidence of gingivitis, and compared with zirconia crowns, metal-ceramic crowns demonstrated significantly more inflammation.