Comparison of the Crestal Bone Loss Between Implant-Supported Prosthesis With Sinus Augmentation and Distal Cantilevered Implant-Supported Prosthesis Without Sinus Augmentation
This study aimed to compare the crestal bone loss between a 2-implant–supported, noncantilevered 3-unit fixed partial prosthesis (TUFPP) with sinus augmentation and a 2-implant–supported, distal cantilevered TUFPP without sinus augmentation in the posterior maxilla having insufficient crestal bone. The study subjects were enrolled in 2 groups. Group 1 included patients with 2 implants: an anterior implant placed in the native bone and a posterior implant inserted with simultaneous sinus augmentation using a xenogenic bone graft to support a TUFPP. Group 2 included patients with 2 implants inserted in the native bone to support a distal cantilevered TUFPP. The crestal bone levels at the distal and mesial aspects of each implant were measured at baseline and 6-, 12-, and 24-month follow-up controls on panoramic radiographs. Fifty-two patients and 104 implants were included. There was a significant difference in distal crestal bone loss between anterior and posterior implants in group 1 at 6 months (P < .05) but not at 12 and 24 months (P > .05). Distal crestal bone loss was significantly increased in group 1 posterior implants compared to the group 2 posterior implants at 6 months (P < .05). There was no significant difference in mesial bone loss between the anterior and posterior implants in both groups at all follow-up controls (P > .05). There was also no significant mesial crestal bone loss in relation to the anterior and posterior implants of both groups at all follow-up controls (P > .05). Noncantilevered 2-implant–supported TUFPP with sinus augmentation may have similar medium-term crestal bone loss when compared to cantilevered 2-implant–supported TUFPP without sinus augmentation. Further prospective studies should be designed to compare the performance of the 2-implant–supported cantilevered TUFPP and 2-implant–supported TUFPP with sinus augmentation.

Figure 1. (a) In the schematic drawing of group 1, the anterior implant of the 2-implant–supported 3-unit fixed prosthesis was inserted into the native bone, and distal implant was inserted with a sinus augmentation procedure. White area around the distal implant demonstrates the grafting material. (b) A 2-implant–supported 3-unit fixed prosthesis inserted with sinus augmentation can be seen on the left maxillary posterior region on the panoramic radiography. Figure 2. (a) In the schematic drawing of group 2, anterior and posterior implants of the 2-implant–supported distal cantilevered 3-unit fixed prosthesis were inserted into the native bone. (b) A 2-implant–supported distal cantilevered 3-unit fixed prosthesis inserted without sinus augmentation can be seen on the left maxillary posterior region on the panoramic radiography.

Figure 3. Box plot demonstrating the mean values of distal crestal bone loss in relation to the anterior and posterior implants of groups 1 and 2 at 6-, 12-, and 24-month follow-up evaluations. Figure 4. Box plot demonstrating the mean values of mesial crestal bone loss in relation to the anterior and posterior implants of groups 1 and 2 at 6-, 12-, and 24-month follow-up evaluations.
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