The BAOSFE technique caused perforations in the membrane in 7 out of 12 cases with a percentage of 58.4. This result is consistent with many previous studies which state that this technique has a high rate of perforations when the RBH is less than 5 mm [2, 7, 26]. Also, all the perforations happened during the elevation process; however, this percentage is different than that reported by Steltzle (100%) in a similar study as the intended elevation height was less by 3 mm in our study [7].

For the balloon technique, only one perforation happened during the elevation process and the balloon was able to lift the membrane for 7 mm in all successful cases. This result supports various studies that showed a high success rate for this technique [6, 7, 13]; however, the osteotomy should be enlarged to 5 mm before inserting the balloon and this might limit the indications for this technique in thin ridges.

The CAS kit caused perforation of the Schneiderian membrane in one of the 12 cases (8.3%) which happened during the osteotomy. This is the first study to our knowledge to assess the CAS kit form OSSTEM implants since we found one published article that was a questionnaire sent to dentists who used the system to assess their satisfaction with the CAS kit, The study reported a membrane perforation rate of 4.1%. This percentage is smaller than that reported in our study (8.3%); however, we believe that our method of checking perforations is more accurate. Also, the difference in sample size may have contributed to the outcome [5].