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Treatment Algorithm · Module
Posterior maxilla: which sinus approach?
Selecting a sinus floor elevation technique from residual bone height (RBH) and the ability to achieve primary stability. Transcrestal for modest lifts, lateral window for larger gains, staged when stability cannot be met.
Use: Posterior maxilla planning
Key driver: Residual bone height
Imaging: CBCT mandatory
01 — Pre-surgical
Assess before you choose
RBH below the sinus floor is the primary determinant, but membrane anatomy and pathology can override the technique choice. Always evaluate on CBCT.
Measure
Residual bone height
- Vertical bone below sinus floor
- Determines stability & approach
- Measure at each planned site
Check
Membrane & anatomy
- Schneiderian thickness, septa
- Ostium patency, lateral wall thickness
- Alveolar antral artery position
Rule out
Sinus pathology
- Acute sinusitis, large cysts
- Refer to ENT if indicated
- Optimize before grafting
Modify
Patient risk
- Smoking impairs graft healing
- Allergic rhinitis, prior surgery
- Adjust consent & prognosis
02 — Decision Pathway
Interactive approach selector
Choose by residual bone height and the vertical gain required. Thresholds are typical ranges — membrane anatomy and operator experience shift the boundaries.
Tap the residual bone height band measured on CBCT.
Step 1 — Residual bone height below the sinus floor
RBH ≥ 8–10 mm
Adequate height
Often no sinus lift needed.
RBH ~6–8 mm
Modest lift required
Primary stability achievable.
RBH ~4–6 mm
Borderline
Technique-sensitive; stability variable.
RBH < 4 mm
Severely deficient
Large vertical gain needed.
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03 — Quick Reference
Approach comparison
| Transcrestal (osteotome / crestal) | Lateral window |
|---|
| Typical RBH | ≥ 5–6 mm | < 4–5 mm |
| Vertical gain | ~2–4 mm | Larger, more predictable gain |
| Implant timing | Usually simultaneous | Simultaneous if stability obtainable, else staged |
| Morbidity | Lower, less invasive | Higher, flap + window |
| Membrane access | Blind elevation | Direct visualization |
Reference
Sources & clinical disclaimer
For licensed clinicians — educational use only. This algorithm summarizes published consensus and is not a substitute for individual clinical judgment, examination, or the standard of care in your jurisdiction. RBH thresholds are ranges, not fixed rules; CBCT assessment and operator experience govern the final decision.
- Jensen OT, et al. Report of the Sinus Consensus Conference of 1996. Int J Oral Maxillofac Implants. 1998;13(Suppl):11–45.
- Pjetursson BE, et al. Transalveolar sinus floor elevation — systematic review. J Clin Periodontol. 2008;35(Suppl 8):216–240.
- Wallace SS, et al. Maxillary sinus elevation by lateral window approach — EAO consensus / systematic reviews. Clin Oral Implants Res. 2012.
Last reviewed: June 2026 · Next review due: June 2027 · Version 1.0