Sinus floor elevation: transcrestal
Introduction
After tooth removal in the posterior maxilla, significant sinus pneumatization often occurs. The extent of this pneumatization can vary considerably (Levi et al. 2017, Cavalcanti et al. 2018, Hameed et al. 2019). The vertical dimension of the alveolar bone will reduce from two directions (coronally and apically), which may hinder optimal implant positioning (Tatum 1986). This resorption typically occurs within a short period after tooth extraction. Therefore, reconstruction and elevation of the maxillary sinus might be necessary when implants are needed.
If there is sufficient residual bone height (e.g., ≥ 3 mm), a crestal approach can be selected. However, in cases of insufficient residual bone height, low bone density, or a wide sinus (bucco-palatal width), a window approach is recommended (Valentini et al. 2025).
Protocol: step by step
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make a crestal incision and reflect a small muco-periosteal flap,
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prepare the osteotomy (up to 1 mm distance from the floor of the sinus),
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apply 1 L-PRF membrane in the osteotomy (= cushion for osteotome),
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gently fracture the floor of the sinus using an osteotome, or remove the last mm with a piezo instrument or osseo-densifying burs,
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apply 3-5 L-PRF membranes via the osteotomy to elevate the sinus membrane,
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insert the implant,
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suture to achieve primary closure,
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if good primary stability of the implant is achieved, immediate abutment connection can be considered.
Video: Transcrestal sinus floor augmentation
After preparing the osteotomy up to 1 mm from the floor of the sinus, the last millimeter can be fractured with an osteotome (using an L-PRF membrane as a cushion) or removed with another technique (e.g., piezo device, osseo-densification burs). At this stage, several membranes need to be inserted into the sinus via the osteotomy (using an osteotome) to lift the sinus membrane. A total of 4 to 5 membranes are required for a single implant to gain sufficient bone height. Finally, the implant can be placed, and its coverscrew can eventually be covered with an L-PRF membrane to speed up the soft-tissue healing. Alternatively, if good primary stability is achieved, a healing abutment can be inserted at the same session.
Cases
(d = day, w = week, m = month, y = year)
1: Transcrestal sinus floor elevation
d 0: preparation of an osteotomy up to 1 mm away from the sinus.
d 0: apply several extra L-PRF membranes via the osteotomy and insert with an osteotome.
m 6: RX at implant loading (red = initial floor, white = new floor of the sinus).
d 0: apply 1 L-PRF membrane to prevent a perforation when fracturing the sinus floor.
d 0: before implant insertion (5 L-PRF membranes had been applied).
m 14: RX showing increased calcification of the regenerated bone.
d 0: careful fracturing of the floor of the sinus with an osteotome.
d 0: intra-oral RX; the apex of a conical implant is ± 5 mm into the augmented area of the sinus (red = initial floor sinus).
y 7: digital RX indicating (together with the PPD) a stable marginal bone level.
2: Transcrestal sinus floor elevation
d 0: sagittal CBCT image of an implant, which is ± 5 mm into the augmented area (L-PRF membranes only).
d 0: bucco-palatal cross-section (CBCT image) after intervention showing the fractured part of the sinus floor.
m 4: sagittal CBCT image highlighting the increase in bone height.
m 4: sagittal CBCT image (red = the initial floor, white = the new floor of the sinus).
m 4: cross-sectional CBCT (B-P cut) with the regenerated bone.
m 4: cross-sectional CBCT; the augmentation was obtained without a bone substitute.
m 4 & y 4: intra-oral RX showing a stable marginal and apical bone level over time.
Data:
Clinical trials applying L-PRF during transcrestal sinus floor elevation
Abbreviations: Study type: RCT = randomized controlled trial; info on surgery: RBH = residual bone height; Substitute: L-PRF = leucocyte- and platelet-rich fibrin, A-PRF = advanced platelet rich fibrin, CGF = concentrated growth factor, # = several, m = membrane, cl = clot, pl = plug, TC = transcrestal, LW = lateral window, + G = with bone graft, - G = without bone graft, DBBM = deproteinized bovine bone mineral; Outcome: T = test, C = control.
Conclusion
Twelve of the thirteen included papers presented data on vertical bone gain (VBG), with an overall mean gain of 4.6 mm (SD 1.8 mm). Two RCTs compared the VBG between the use of L-PRF or saline, finding significantly greater gains with L-PRF. Two RCTs (Chen et al. 2022, Huang et al. 2024) compared the VBG between the sole use of L-PRF with the use of DBBM, observing no significant differences. These papers also followed the VBG over time and registered a slight resorption (0.1 to 0.4 mm). Huang and co-workers (2024) identified a narrow residual bone height and a large sinus width (bucco-palatal direction) as negative predictors for the VBG.
Twelve papers also reported on implant survival, with an overall survival rate of 97.7% (SD 3.0). For more information, see Valentini et al., 2025.
Decision tree for a transcrestal sinus floor elevation (Miron & Pikos 2018, Valentini et al. 2025)
Important Notice
Clinical experience:
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Use 1 L-PRF membrane as a "cushion" when fracturing the sinus floor with an osteotome.
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Apply ≥ 3 L-PRF plugs/membranes per osteotomy (one per required millimeter of bone gain).
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Membranes and plugs are superior to clots.
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Remember that there will be a 20% resorption during the healing phase.
Additional Benefits:
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L-PRF will give a better bone quality without "remaining" bone substitute.
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L-PRF will lead to a 100% autogenous therapy without foreign bodies.
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In case of a perforation of the sinus membrane, only autogenous material will reach the sinus.
Failures:
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In case of a sinus membrane perforation, the amount of bone gain is minimal (use the Valsalva maneuver?).
Interesting references
Several videos and/or cases on this webpage are discussed more in detail in the following book: Quirynen M & Pinto N 2022. Leukocyte- and Platelet-Rich Fibrin in Oral Regenerative Procedures. Quintessence Publishing;
ISBN: 978-1-78698-105-9