RESUMEN
<p><b>OBJECTIVE</b>To evaluate the clinical performance of the two configurations of gingival margin preparation of tooth.</p><p><b>METHODS</b>The cases in this study were divided into two groups according to different tooth defects. Each group consisted of 40 cases. One group's gingival margin configuration was 90 degree shoulder, the other was under-gingival non-shoulder. The clinical performance of these restorations was followed up for 1 year and 2 years. The evaluators examined the restorations for plaque index, gingival index, marginal discolor and marginal fit.</p><p><b>RESULTS</b>There was no significant difference in the evaluators between the two groups.</p><p><b>CONCLUSION</b>The under-gingival non-shoulder margin configuration of porcelain fused to metal should be used for clinical application compared with the 90 degree shoulder one in certain circumstance.</p>