Comparative Evaluation of Indirect Sinus Lift Using CMC Technique Versus Direct Sinus Lift Via Lateral Window Technique in Subantral Type IV

Background: Maxillary sinus augmentation is a common implant placement procedure when residual bone height (RBH) in the posterior maxilla is limited, especially in subantral type IV cases. A less invasive alternative to the traditional lateral window procedure is the crestal approach using the CMC (Crestal approach with membrane Control) technology. Objective: To evaluate the differences between the CMC technique and the conventional lateral window approach in terms of clinical performance, bone density results, surgical time, and complication rates for sinus lifting in subantral type IV cases. Methods: Twenty patients with posterior maxillary edentulism and RBH < 5 mm were divided into two groups at random: Group A (n = 10) received direct sinus lift using the lateral window approach, and Group B (n = 10) received indirect sinus lift using the CMC technique. Four sites (crestal, apical, buccal, and palatal) in Hounsfield Units (HU) were evaluated for bone density using CBCT scans both before and four months after surgery. A “visual analog scale” was used to quantify patient discomfort, postoperative problems, and surgery time. Results: Both methods proved highly effective for implant placement and sinus augmentation, with both groups showing a notable increase in postoperative bone density. Although the CMC group's generally had a shorter surgical time, but with high-density cortical bone, the advantages of shorter time decrease, and the procedure could take as long as the lateral approach. Postoperative pain was generally lower in the CMC group, VAS pain scores were lower (3.4 vs. 4.9). The most frequent complication was edema, which was more pronounced in the lateral window group. Membrane perforation occurred occasionally in both groups. Additionally, minor complications included vertigo, sinus pressure, epistaxis, and nausea, with variations related to bone density and sinus membrane thickness. Conclusion: In situations of subantral type IV, both sinus lift procedures are clinically beneficial. With good patient outcomes, lower morbidity, and sufficient bone regeneration, the CMC approach provides a less invasive alternative. Anatomical characteristics unique to each patient, membrane thickness, and bone quality should all be taken into account when choosing a procedure.