# Crystal Sinus Lift with the Hydrodynamic Technique: Prospective Clinical Study at 3 Years Follow-Up
## 4 Discussion  
The effectiveness and safety of transcrestal sinus lift procedures with simultaneous implant placement have been well documented in the literature. Our study adds to this body of knowledge by demonstrating high implant survival rates and acceptable levels of marginal bone loss over a three-year follow-up period. The implant survival rate observed in our study was 98.04%, which is consistent with previous reports in the literature. For instance, [PERSON] et al. (2015) and [PERSON] et al. (2024) reported similar survival rates for implants placed in the atrophic posterior maxilla using various sinus lift techniques [6; 9]. These findings are further corroborated by [PERSON] et al. (2008), who highlighted the success of sinus floor elevation and the survival of implants inserted in combination with this procedure [29]. The marginal bone loss (MBL) documented in our study showed a significant increase within the first year post-surgery, followed by stabilization in subsequent years. This trend aligns with findings by [PERSON] et al. (2021) and [PERSON] et al. (2023), who also observed early bone remodeling followed by a plateau phase [12; 20]. The average MBL at three years was 1.02 \(\pm\) 1.01 mm, which is within the acceptable range reported by the International Team for Implantology (ITI) consensus guidelines. Studies by [PERSON] et al. (2024) and [PERSON] et al. (2018) have similarly observed that appropriate techniques and materials can result in stable bone levels over time [9; 30]. The use of digital radiography and precise measurement techniques, as described by [PERSON] et al. (2018), ensures the reliability of these findings [13]. The incidence of surgical complications in our study was minimal and comparable to other studies. sinus membrane perforation, maxillary sinusitis, and graft material displacement each occurred in 1.85% of cases, consistent with the complication rates reported by [PERSON] et al. (2016) and [PERSON] et al. (2022) [8; 18]. The careful execution of the surgical technique, including the use of specialized drills and probes to avoid membrane perforation, likely contributed to the low complication rates observed. Studies by [PERSON] (1986) and [PERSON] et al. (2022) also emphasized the importance of technique in minimizing complications during sinus lift procedures [11; 15]. Our study utilized the xenogenic bone graft in gel form, which has shown promising results in terms of ease of use and effective bone regeneration. This approach is supported by findings from [PERSON] and [PERSON] (2009), who demonstrated the efficacy of gel pressure techniques in flapless transcrestal sinus lifts [17]. Figure 8: Complications recorded during the sinus lift procedures. The Y-axis represents the incidence rate, in percentage (%), of complications, shown on the Y-axis. Additionally, the graftless approaches described by [PERSON] (2020) and [PERSON] et al. (2023) also show comparable outcomes, suggesting that various techniques can be effectively employed depending on the clinical scenario [19,20]. The hydrodynamic properties of the gel form graft, as highlighted by [PERSON] et al. (2017), facilitate a controlled and effective lift of the [PERSON] membrane [31]. The osteetome technique, although not very invasive, has the limitation of hammering, which is often poorly tolerated by patients. Conversely, the crestal approach based on the use of sequential drills, as described by [PERSON], does not present such a drawback [12]. Adequate elevation of [PERSON]'s membrane is an essential prerequisite for the creation of a sub-antral space with regenerative potential. Recent studies have shown a direct correlation between adequate membrane elevation, the formation of new bone tissue, and the volumetric stability of the regenerated tissue [32, 33, 34]. The indirect hydrodynamic detachment of the membrane by the injection of the graft in gel form was simple, quick, and effective [35].