Use of a Soft, Moldable Biomaterial for Internal (Transcrestal) Maxillary Sinus Floor Elevation: A Case Report
November 1, 2026
Volume 47
,
Issue 8
,
November/December 2026
Page(s): 388
Abstract: Rehabilitation of the posterior maxilla is frequently complicated by reduced residual bone height resulting from sinus pneumatization and alveolar resorption. The lateral window approach is technique-sensitive and associated with relatively high morbidity, while the conventional transcrestal (osteotome) approach can produce benign paroxysmal positional vertigo and carries a risk of Schneiderian membrane perforation that may be aggravated by the sharp edges and condensation forces associated with particulate graft materials. This report describes a transcrestal maxillary sinus floor elevation in a 73-year-old man, performed with piezoelectric instrumentation and a soft, moldable bovine collagen/calcium phosphate biomaterial used to atraumatically elevate the sinus membrane while an implant was placed simultaneously at the maxillary left first molar site. Digital planning enabled volumetric control of the augmentation, and the pliable graft body distributed elevation forces uniformly across the membrane rather than at discrete points. Postoperative cone-beam computed tomography demonstrated a smooth radiopaque dome apical to the implant, which osseointegrated and was restored with stable peri-implant bone levels at 10 months’ follow-up. The combination of digital planning, piezoelectric surgery, and a conformable biomaterial may offer a controlled, lower-morbidity alternative for transcrestal sinus floor elevation.
Predictable implant rehabilitation of the posterior maxilla is often limited by insufficient residual subantral bone, a consequence of both maxillary sinus pneumatization and post-extraction alveolar bone remodeling. Maxillary sinus floor elevation to create the bone volume required for implant placement has been performed for more than four decades, as initially reported by Boyne and Tatum.1,2 This is commonly achieved through one of two routes: a lateral (window) approach or a transcrestal (crestal) approach.
The lateral window approach provides direct access and broad visualization yielding high implant survival. However, it is technique-sensitive, requiring a larger flap and longer treatment course than other sinus augmentation approaches, and is associated with greater patient morbidity and a measurable incidence of intraoperative complications such as membrane perforation.3-6 These factors can be a deterrent for patients, particularly those who have previously undergone lateral augmentation.
The transcrestal approach, popularized as the osteotome technique,7 is less invasive and allows simultaneous implant placement when adequate primary stability can be obtained. However, the mallet percussion historically used to in-fracture the sinus floor has been linked to benign paroxysmal positional vertigo (BPPV).8,9 This elevation technique is performed with limited direct vision, so the sinus membrane can be inadvertently perforated. This risk is compounded when particulate grafts are condensed into the osteotomy, because the sharp edges of the granules and the apical condensation forces can stress or tear the sinus membrane.4,10
Piezoelectric surgery selectively cuts mineralized bone while tending to spare soft tissue, and its use during sinus augmentation surgery has been associated with reduced membrane perforation.11-13 Building on this, a graft material that is soft and moldable rather than particulate may further protect the sinus membrane by conforming to the sinus floor and elevating it over a broader surface. This case report describes a transcrestal sinus floor elevation that combined digital planning, piezoelectric instrumentation, and a soft, moldable bovine collagen/calcium phosphate biomaterial.
Case Presentation
A 73-year-old man was referred by his prosthodontist for implant restoration of the maxillary left quadrant. He had a history of prior lateral (external) maxillary sinus augmentation and implant placements in sites Nos. 13 and 15, which were restored previously, and he expressed specific concern about the morbidity and recovery associated with that type of surgery. Recently retired and planning to relocate, he prioritized a less invasive option with a shorter overall treatment time.
The patient was a nonsmoker with well-controlled hypertension and benign prostatic hyperplasia (American Society of Anesthesiologists [ASA] II). Preoperative cone-beam computed tomography (CBCT) demonstrated a pneumatized left maxillary sinus with a residual bone height of approximately 4.9 mm and a ridge width of 6.5 mm at the planned implant site (tooth No. 14) (Figure 1). No sinus pathology or mucosal thickening were identified that would contraindicate the planned procedure.
The treatment options presented to the patient were: (1) a repeat lateral window augmentation with delayed implant placement; (2) a transcrestal sinus floor elevation with simultaneous implant placement; and (3) no treatment and proceed with an alternative prosthesis supported by existing implants (Nos. 13 and 15). After discussion of the risks, benefits, and expected recovery of each, the patient elected the second option, transcrestal sinus floor elevation with simultaneous implant placement, to minimize morbidity and treatment time.
Surgical Procedure and Technique
To overcome the aforementioned limitations of the traditional approaches, a digitally planned internal sinus floor elevation was performed. The preoperative CBCT was used to plan the implant position and the precise vertical augmentation required, allowing the graft volume to be controlled and avoiding any overgrafting that is sometimes seen with lateral approaches.
Following local anesthesia and elevation of a full-thickness crestal flap, the implant osteotomy was prepared. Piezoelectric instrumentation (Piezomed, W&H, wh.com/en_global) with sinus-specific tips (Z35P, Z25P) was then used to complete the osteotomy (Figure 2 and Figure 3) and elevate the Schneiderian membrane, selectively removing bone at the sinus floor while protecting the membrane. Membrane integrity was assessed using the Valsalva maneuver, in which the patient was asked to exhale gently through the nose with the nostrils pinched closed; billowing of the elevated Schneiderian membrane without air escaping into the surgical field was taken to indicate an intact membrane.
A soft, moldable bovine collagen/calcium phosphate plug (OsteoGen®, Impladent Ltd., impladentltd.com) was trimmed to the planned dimensions and gently advanced through the osteotomy to elevate the membrane (Figure 4 and Figure 5). Because the material is pliable, it conformed to the contour of the sinus floor and distributed the elevation force uniformly across the membrane, tenting it atraumatically and avoiding the point-loading stress and sharp edges associated with particulate graft packing. A 4.1 mm x 8 mm implant (Straumann BLC™, Straumann, straumann.com) was placed freehand simultaneously at site No. 14, achieving an insertion torque of 35 Ncm indicating adequate primary stability for the planned protocol. A cover screw was placed and the flap was closed with polytetrafluoroethylene (PTFE) sutures (Figure 6). Periapical radiographs were obtained at multiple stages to confirm implant position and graft placement (Figure 7).
Postoperative Course and Follow-up
The patient was prescribed an antibiotic (amoxicillin 500 mg, three times a day for 10 days) and analgesic (alternating ibuprofen 400 mg and acetaminophen 325 mg, four times a day for 3 days and as needed for another 4 days) and given standard sinus precautions. Soft-tissue healing was uneventful, with no signs of infection or further complications. Postoperative CBCT revealed a distinct, smooth radiopaque dome apical to the implant fixture at site No. 14, consistent with an isolated, well-contained subantral graft space (Figure 8).
After a healing period of 5 months, the implant was uncovered and restored with a final restoration (Figure 9). At approximately 10 months’ follow-up, the implant remained osseointegrated and functional, with stable marginal and peri-implant bone levels and maintenance of the augmented subantral volume (Figure 10 and Figure 11). The final implant-supported restoration is shown in Figure 12 and Figure 13.
Discussion
Traditional transcrestal sinus elevation carries an inherent risk of Schneiderian membrane micro-perforation owing to the sharp edges of particulate grafts, the condensation forces required to advance them, and the limited direct access of the crestal approach. This case illustrates that combining digital planning, piezoelectric surgery, and a soft, moldable biomaterial can provide a more controlled alternative. The pliability of the graft body allows uniform, atraumatic tenting of the membrane without point-loading stress, creating an isolated, stable compartment for osteoconduction, while the use of piezoelectric tips rather than mallet-driven osteotomes removes the percussive forces implicated in BPPV.8,9,11
Digital planning contributed to predictability by defining the implant position and the required vertical gain in advance, helping to control graft volume and avoid overgrafting. These observations are consistent with the literature: implant survival after transcrestal elevation is comparable to that reported for the lateral approach,3,4 piezoelectric instrumentation is associated with reduced membrane perforation in sinus surgery,12,13 and successful elevation can be achieved with a range of graft strategies, including grafted and graftless transcrestal techniques.14-16
The favorable outcome observed in this case warrants further validation, and controlled clinical trials with histologic and longer-term radiographic endpoints are needed to substantiate the technique and compare it directly against established transcrestal methods.
Conclusion
This case demonstrated the use of a soft, moldable collagen/calcium phosphate biomaterial combined with digital planning and piezoelectric surgery to enable a controlled, atraumatic transcrestal maxillary sinus floor elevation. The graft material functioned as a protective apical cushion for the Schneiderian membrane and supported successful implant osseointegration at ≥10-month follow-up. Further controlled clinical trials are recommended to validate these findings.
DISCLOSURE
The authors had no conflicts of interest to report. The bone graft material used in this article was donated by Impladent Ltd. The funding source was not involved in the study design, execution, analysis, or decision to publish.
ABOUT THE AUTHORS
Nika Mehrnia, DDS
Research Fellow, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts; Graduate Scholar, ADA-Forsyth Institute, Somerville, Massachusetts; Private Practice limited to Periodontology and Implant Dentistry, Boston, Massachusetts
Estar Rani Vallapu, BDS, MS
Private Practice limited to Periodontology and Implant Dentistry, Boston, Massachusetts
Irina F. Dragan, DMD, DDS, MS, eMBA
Adjunct Associate Professor of Periodontology, Tufts University School of Dental Medicine, Boston, Massachusetts; Lecturer, Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts; Private Practice limited to Periodontology and Implant Dentistry, Boston, Massachusetts
