## 1 Introduction  
Removable complete or partial dentures may replace dedulous areas; however, using removable dentures minimizes taste perception and masticatory capacity [1]. As a result, dental implants have become a reliable treatment option for eligible patients [2]. However, implant success is related to bone quality and quantity [3]; most implant failures occur in the maxillary molar region due to poor bone quality [4, 5]. Other factors that could lead to implant failure and complexity in the posterior maxilla include decreased interarch space and gross sinus pneumatization due to alveolar ridge atrophy. In these cases, sinus augmentation is recommended so as to create enough vertical bone volume to allow implant placement with sufficient stability [6].  
Several treatment options for a vertically deficient, dentulous posterior maxillary have been postulated. Traditionally, two approaches have been used: direct sinus elevation through a lateral window approach and indirect sinus elevation through a crestal approach [7]. The lateral window technique produces a predictable clinical outcome [8]. However, the procedure's invasiveness, the patient's morbidity, the risk of severing the alveolar antral artery, the risk of sinus membrane perforation, the delay in healing, and the enhanced risk of postoperative infection are major disadvantages [9]. Transcrestal indirect sinus elevation procedures, on the other hand, require less time, are less invasive, and have a lower morbidity rate. Yet, the possibility of membrane perforation is almost 24% due to a lack of direct access and visibility [10].  
Numerous surgical methods for the indirect lift of the sinus membrane have been developed. [PERSON] described the osteetome sinus floor elevation (OSFE) technique in 1994, which used an osteetome to fracture the sinus floor and lift the sinus membrane, facilitating the placement of graft materials and implants in the subantral space through the osteotomy site [11]. This procedure has some drawbacks, including exposure to the explosive force of the maxilla with inadequate control, inadvertent displacement or fracture, membrane perforation, benign paroxysmal positional vertigo, and patient pain [12].  
Using piezoelectric ultrasound was proposed as an efficient alternative for maxillary sinus lift procedures [13]. This device's ability to selectively cut only mineralized structures without harming soft tissues is an important feature [13,14]. Furthermore, no perforation of the Schneiderian membrane occurs during the lateral antrostomy piezoelectric preparation [15]. Thus, piezosurgery was employed to expose the maxillary sinus mucosa through the alveolar crest while simultaneously elevating the sinus floor with hydraulic pressure for graft and implant insertion. The advantages of this method include reduced trauma, less sinus membrane perforation, the lack of malleting, and shorter surgery times. However, membrane perforation via high hydraulic pressure may occur [16].  
As a new bone instrumentation technique, osseous densification, a biomechanical osteotomy method, uses a non-excavating drilling process to preserve bone [17]. It is recommended that practitioners employ drills with tapered geometry and carefully constructed flutes to gradually expand the osteotomy while securing bone to its walls and apex. Since compaction autografting causes an elastic \"spring-back\" effect in the prepared osteotomy, this bone densification method boosts the implant's primary stability [17].  
It has been acknowledged that CBCT is valuable in implant treatment planning and in postimplant and/or postgrafting evaluation. CBCT is also used to detect bone height, assess marginal bone loss, and determine bone density around implants [18,19].  
The present randomized clinical trial (RCT) evaluated dental implant stability, vertical bone gain, bone density, and crestal bone loss after a crestal sinus lift as performed using different techniques (Densah burs, piezosurgery, and osteetome) in the posterior maxilla of deficient height.