Purpose: Two different stereolithographic surgical guide systems, NobelGuide (Nobel Biocare) and SimPlant (Materialise), were compared clinically, and the survival rates of the planned immediately loaded dental implants with prefabricated provisional restorations were evaluated. Materials and Methods: Patients were treated with implants using either the Materialise SimPlant system or the Nobel Biocare system. All implants were planned on cone beam computed tomography (CBCT) or CT-derived images. Mucosa-, bone-, or tooth-supported stereolithographic guides were produced using the two commercial systems. A provisional was placed immediately after implant insertion in all cases. Results: Fourteen patients were enrolled. Seventy-five implants were placed (34 with Materialise, 41 with Nobel Biocare) using stereolithographic surgical guides. All but one implant were loaded immediately with prefabricated provisionals. In all cases, implants were in place for a minimum of 12 months. No complications related to associated anatomy occurred. One implant failed, leading to a combined cumulative survival rate of 98.7%. There were no other intraoperative or postoperative complications. Implants placed by bone-supported guides had increased patient symptoms of postoperative swelling and discomfort. All provisionals were successful. Conclusions: Both types of stereolithographic surgical templates were sufficiently accurate in transferring the planned implant positions to the surgical field, allowing the placement of prefabricated provisionals. These technologies are most beneficial in patients in whom the simultaneous placement of multiple implants in combination with complex restorations is planned. Palabras clave: guided surgery, stereolithography, surgical template, computed tomography, implant, immediate loading