BACKGROUND: The purpose of this clinical study was to compare the marginal adaptation of infrastructure design with 4 different techniques.
MATERIAL AND METHODS: Forty tissue-level implant abutments (NTA, Shorter) were inserted on implant analogs. The samples were placed randomly in the wax blocks in the arch form of the upper jaw so that there would be 10 in each group. Test samples were obtained using the conventional casting method (CC), milling from metal blocks method (MB), direct metal laser sintering method (LS), and Noritake Alliance (NA) system. Data were analyzed by ANOVA with t tests.
RESULTS: After porcelain oven-drying, marginal gaps of metal substructures obtained by using conventional casting and milling methods were observed to decrease. The smallest value of the marginal gaps was found in the Noritake (NA) system, and the largest value in the milling (MB) method before and after oven-drying. The marginal gap of the direct metal laser sintering method was not significantly different from the change in the marginal gap of other metal substructures (p>0.05).
CONCLUSIONS: The marginal gap of the substructures obtained using the direct metal laser sintering method was not significantly different from the change in marginal gap of other metal substructures (p>0.05).

Keywords: Dental Abutments, Dental Implant-Abutment Design, Dental Marginal Adaptation, Dental Restoration, Permanent