There Were Three Millimetres of Bone Where He Needed Ten

Quick answer: Upper back teeth sit directly beneath the maxillary sinus. When one is lost, the bone shrinks and the sinus expands downwards, often leaving too little bone for an implant. A sinus lift creates that bone by raising the sinus lining and grafting underneath it.

The call

He had been told at two practices that an implant was not possible. Neither had explained why, which is the part that had frustrated him more than the answer.

Dani, 52, from Nofei Aviv, had lost an upper first molar about nine years earlier. He had managed with the gap and had recently started noticing that the opposing lower tooth had grown down into it and food was packing at the site.

What we found

The gap itself was unremarkable — healed, adequate width, healthy neighbouring teeth.

The CBCT scan explained the previous refusals. Between the crest of the ridge and the floor of the maxillary sinus there were 3.2mm of bone. A standard implant in that region needs somewhere in the region of 8 to 10mm.

Why this happens, and why it is so common at upper back teeth. Two processes work in the same direction. The ridge resorbs from above after a tooth is lost, as it does anywhere. And the sinus itself pneumatises — the air space expands downwards into the space the tooth roots used to occupy. Nine years is ample time for both.

The opposing lower molar had over-erupted by about 2mm, which is what happens to an unopposed tooth and which had reduced the space available for a crown.

The two techniques, and which one applies depends entirely on how much bone is there:

The transcrestal approach. Where roughly 5mm or more of bone remains, the sinus floor can be lifted gently through the implant channel itself, with graft material pushed up beneath the lining, and the implant placed at the same appointment. Less invasive, faster, and it needs that starting bone height.

The lateral window approach. Where there is less, a small window is opened in the side wall of the sinus, the lining is carefully elevated off the floor, graft material is packed into the space created, and the implant is placed several months later once that graft has matured into bone.

At 3.2mm, his was clearly the second.

The risk that has to be explained. The sinus lining — the Schneiderian membrane — is thin, and perforating it is the commonest complication of the procedure. Small perforations are repairable with a membrane during surgery. Larger ones mean abandoning the graft and returning months later.

We also checked his sinus health on the scan. Active sinusitis, significant lining thickening or a blocked drainage pathway would have meant an ENT opinion first, because grafting into an unhealthy sinus invites infection. His was clear.

What we did

Lateral window sinus lift. Under local anaesthetic with sedation, about ninety minutes. A flap raised, a window prepared in the lateral wall with a piezoelectric instrument rather than a rotary bur — it cuts bone and not soft tissue, which reduces the perforation risk substantially. The lining elevated carefully, graft material placed, a membrane over the window, and the flap closed.

Post-operative instructions specific to sinus surgery, which are not the same as for an ordinary extraction: no nose blowing for two weeks, sneeze with the mouth open, no straws, no flying for two weeks, no swimming, and no heavy lifting. All of these raise or lower sinus pressure, and pressure displaces the graft.

Antibiotics, a decongestant, and a saline nasal spray.

Swelling and bruising for about a week, which was described beforehand — patients who are not warned about facial bruising after this procedure become alarmed.

Six months of healing, confirmed with a repeat scan showing 11mm of consolidated bone.

Implant placed at six months, crown at nine.

The over-erupted lower molar was adjusted slightly and, because the reduction needed was more than enamel would allow, crowned.

The outcome

Functioning well at three years, with normal bone levels and no sinus symptoms at any stage.

Nine months from first appointment to final crown, and two surgical procedures. That is what "not possible" actually meant at the other two practices — not impossible, but requiring a step neither had offered.

What to do if this happens to you

1. Ask why, if you are told an implant is not possible. There is usually a specific measurement behind it.
2. Ask for a CBCT scan. Bone height at the back of the upper jaw cannot be judged from a standard x-ray.
3. Ask which technique applies — transcrestal or lateral window. They differ substantially in time and recovery.
4. Disclose any sinus problems, including recurrent sinusitis or previous surgery.
5. Follow the pressure instructions exactly. No nose blowing, no flying, no straws.
6. Ask about replacing the tooth sooner next time. Nine years of bone loss created this.

Told there is not enough bone for an implant? Ramat Beit Shemesh Urgent Dental Care will show you the scan and the options. 055-985-8845 · WhatsApp https://wa.me/972559858845 · Harav Kook 28/1, Beit Shemesh

This is a composite clinical story. It reflects a presentation we see regularly in Beit Shemesh and Ramat Beit Shemesh; the name and details are illustrative and are not those of a real patient.