ABSTRACT
<p><b>OBJECTIVE</b>To compare the influences of gold alloy metal crown and Ni-Cr alloy metal crown on gingival health.</p><p><b>METHODS</b>Totally 20 patients requiring one metal crown restoration were divided into the gold alloy metal crown group (n=9) and Ni-Cr alloy metal crown group (n=11). The contra-lateral homonymy natural healthy teeth served as controls. Before the tooth preparation and 6 months after crown placement, the weight of gingival crevicular fluid (GCF) of each tooth (included the test teeth and the control teeth) was measured, and the probing depth and the sulcus bleeding index of each tooth were also recorded.</p><p><b>RESULTS</b>In the gold alloy metal crown group, the weight of GCF detected before the tooth preparation was significantly larger than that detected 6 months after restoration (P<0.05). In the Ni-Cr alloy metal crown group, the sulcus bleeding index recorded 6 months after restoration was significantly larger than that recorded before the tooth preparation (P<0.05). The other experimental indicators were not significantly different before and after restoration.</p><p><b>CONCLUSION</b>The gold alloy metal crowns will not cause obvious harm to the periodontal tissues of the abutments shortly after restoration, while the Ni-Cr alloy metal crowns may increase the risk of sulcus bleeding.</p>