Before augmentation, according to the 3D topography of the alveolar ridge of the patients, the split-box technique was applied if there was more than 3 mm bone thickness at the top of the crest and the bone thickness did not increase towards the lower border.

All surgical procedures were performed under local anesthesia. A mid-crestal incision was made along the ridge crest and two vertical incisions were made at the termination of the crestal incision. All osteotomies were made using with piezoelectric surgery. Horizontal and vertical osteotomies were performed 1.5 mm away from adjacent teeth. Lower border osteotomy of the vestibular cortical bone was performed. A chisel osteoma was used to separate completely and mobilize the segmented bone. This separated, corticocancellous block was stabilized on the distance to the native alveolar crest with micro screws. The space between the block and the alveolar crest was filled with allograft. The flaps were closed using 3-0,4-0 vicryl.

Before augmentation, according to the 3D topography of the alveolar ridge of the patients, the reverse split-box technique was applied if there was more than 3 mm bone thickness at the top of the crest and the bone thickness increase towards the lower border.

This technique differs from the split-box technique as follows: If the bone thickness of the alveolar crest is thick enough to be split, in addition to the bone thickness increases toward the lower border at the alveolar bone, it involves reversing the separated corticocancellous bone block before fixation.

Before augmentation, according to the 3D topography of the alveolar ridge of the patients, the sliding split-box technique was applied if there was less than 3 mm bone thickness at the top of the crest and the bone thickness increase towards the lower border.

This technique differs from the split-box technique as follows: If the bone thickness of the alveolar crest is not thick enough to split at the alveolar crest (<3 mm), but the bone thickness increases toward the lower border of the alveolar bone, horizontal osteotomy is performed at the level where the bone thickness reaches at least 3 mm. Separated corticocancellous bone block is slid toward the coronal of alveolar crest and fixed in line with the native alveolar bone.

In split-box technique, all osteotomies were made using with piezoelectric surgery. Horizontal and vertical osteotomies were performed 1.5 mm away from adjacent teeth. Lower border osteotomy of the vestibular cortical bone was performed. A chisel osteoma was used to separate completely and mobilize the segmented bone. This separated, corticocancellous block was stabilized on the distance to the native alveolar crest with micro screws. The space between the block and the alveolar crest was filled with allograft. In reverse split box technique, differs from the split-box technique as follows: it involves reversing the separated corticocancellous bone block before fixation. In sliding split box technique, differs from the split-box technique as follows: horizontal osteotomy is performed at the level where the bone thickness reaches at least 3 mm. Separated corticocancellous bone block is slid toward the coronal of alveolar crest and fixed in line with the native alveolar bone.

To determine the horizontal changes in the alveolar bone, thickness was measured at two different levels. The measurements were titled as follows: crestal width (CW) and screw level width (SLW).

To measure CW, measurements were made horizontally at the highest point of the crest in pre- and post-operative tomography. To measure SLW, in the post-operative tomography, the bone thickness at the screw level was measured horizontally and recorded. In addition, the distance between the anatomical landmark (mandibular basis, mandibular foramen, lower border of nasal or sinus cavity) and the screw level was also measured and recorded. The main goal of this measurement was to provide a reference for SLW measurement on preoperative cone-beam computed tomography (CBCT), since there were no screws. After the measurements in the postoperative CBCT were made, SLW was also made in the preoperative imaging.

To determine whether there was vertical bone loss during horizontal augmentation, the height of the alveolar ridge (ARH) was measured. To measure ARH, a line was created between the anatomical landmark and the highest point of the crest, and the length of this line was measured in the pre- and post-operative tomography.

In order to determine the difference between the 3 groups in terms of CW, the difference between the pre- and post-operative values of the 3 groups was determined. These values were compared between the 3 groups.