# Bone grafting and sinus lift

> Why the jawbone shrinks after a tooth is lost, how bone grafts, membranes and sinus lifts rebuild it before an implant, and what the risks are. General information.

Source: https://www.nazemalioussef.com/en/clinical-interests/bone-grafting-and-sinus-lift/  
Updated: 2026-09-28

Clinical interest

After a tooth is lost, the bone that held it slowly shrinks. When too little is left to hold an implant, the bone can sometimes be built up first: with a bone graft, or in the upper back jaw with a sinus lift.

From the professional website of Dr Nazem Al Ioussef Published 27 September 2026 Last reviewed 27 September 2026

## Why bone is lost, and who may need a graft

The part of the jaw that surrounds the roots, the alveolar bone, is there to support teeth. Once a tooth has gone, the ridge of bone where it stood gradually becomes narrower and lower. Much of this change happens in the months after the tooth is lost, and it continues more slowly after that. Gum disease, an infection at the root tip, an injury or a difficult extraction can destroy bone as well.

The upper back jaw has a second limit. Above the roots of the upper premolars and molars lies the maxillary sinus, an air-filled space beside the nose. When these teeth are lost, the bone below the sinus can become too shallow to hold an implant of normal length.

A graft is considered when an implant is planned but the bone is too thin or too low, or has a defect. Many people have enough bone and need none. Smoking, diabetes that is not well controlled and some medicines that affect bone make grafting less predictable.

## How bone is rebuilt

### Rebuilding bone for an implant

1. **Bone loss.** After a tooth has gone, the bone can become too thin or too low to hold an implant.
2. **Bone graft.** Graft material fills the defect, often under a protective membrane, and new bone forms over time.
3. **Sinus lift.** In the upper back jaw, the sinus floor is raised and graft placed beneath it, making room for an implant.

Simplified drawing, not to scale.

A bone graft places material where bone is missing. The material works as a scaffold: the body's own bone cells grow into it and, over time, much of it is replaced by new bone. Graft material comes from four kinds of source:

- the patient's own bone, usually taken from another part of the jaw and, for large defects, sometimes from the hip;
- bone from a human donor, processed and sterilised by a tissue bank;
- bone mineral of animal origin, most often from cattle, treated so that only the mineral framework remains;
- synthetic materials, such as calcium phosphate ceramics.

The graft is often covered with a thin membrane. Gum tissue grows faster than bone, and the membrane keeps it out of the space so that bone can form underneath. This is called guided bone regeneration, and it may be done before an implant or at the same time. Most membranes dissolve on their own; many are made of animal collagen, including pig collagen, and others are synthetic. Larger defects sometimes need a block of bone, most often the patient's own, fixed to the jaw with small screws.

When a tooth is taken out, graft material can also be placed in the empty socket straight away. This is called ridge preservation. A Cochrane review found that it may limit how much the ridge shrinks, although the evidence is uncertain.

## The sinus lift

A sinus lift, or sinus floor augmentation, adds height to the bone of the upper back jaw. The floor of the sinus is lined by a thin membrane. During the procedure this lining is gently lifted away from the bone, and graft material is placed in the space created beneath it. There are two main approaches:

- **the lateral window**: a small opening in the side wall of the jaw, on the cheek side, gives access to the lining. It is used when little bone height remains, and the implant goes in at the same visit or after the graft has healed;
- **the crestal approach**: the lining is raised from below, through the site prepared for the implant, by gentle tapping. It needs some existing bone height, and the implant usually goes in at the same visit.

Where some bone height remains, a shorter implant is sometimes an alternative. Research comparing the two has not shown clearly which does better, and sinus lifts have more complications.

## How treatment usually proceeds

1. **Assessment.** An examination and a three-dimensional scan (cone-beam CT) to measure the bone and the sinus. The dentist explains the options, the materials proposed and where they come from, and the risks.
2. **The procedure.** Usually under local anaesthetic, sometimes with sedation. The gum is opened, the graft is placed and often covered with a membrane, and the gum is stitched closed. Grafts taken from the hip are done under general anaesthetic in hospital.
3. **Healing.** The graft matures and new bone forms. This takes time, and how long differs from person to person and with the size of the graft. A temporary tooth can often be worn in the meantime.
4. **Implant placement.** When a check, often with an X-ray or scan, shows enough bone, the implant is placed, unless it went in at the same time as the graft.

## Risks and limits

Swelling, bruising and soreness are common after grafting. Other risks include:

- infection of the graft area, which may need antibiotics and, less often, removal of the graft;
- the gum opening over the graft so that the material or membrane shows;
- the graft not integrating, or too little bone forming for an implant, so that a second graft or a different plan is needed. The risk is higher in smokers;
- in a sinus lift, a tear in the sinus lining. It is usually repaired at the time, but sometimes the procedure is stopped and repeated once the lining has healed. A nosebleed, a blocked feeling in the sinus, sinus infection and, rarely, an opening between the sinus and the mouth can also occur;
- numbness or tingling of the lip, chin, cheek or gum if a nerve is affected. It is usually temporary, but occasionally long-lasting;
- where bone is taken from elsewhere in the jaw or from the hip, pain and bruising at that site as well.

A graft improves the conditions for an implant. It cannot promise that an implant will be possible afterwards, or how long an implant will last.

## Healing and aftercare

The dentist gives written instructions. They usually include pain relief as advised, soft food, gentle cleaning near the stitches, and not smoking, which slows healing and raises the risk of the graft failing. After a sinus lift, it is usual to avoid blowing the nose hard for as long as the dentist advises. A denture may need adjusting so that it does not press on the graft. Pain or swelling that gets worse, a fever or a discharge should be reported to the dentist promptly.

Bone grafting is usually one stage of [implant treatment](https://www.nazemalioussef.com/en/clinical-interests/dental-implants/). Much of the bone lost around teeth is lost to [gum disease](https://www.nazemalioussef.com/en/patient-guides/gum-disease/), so keeping the gums healthy protects the bone that is still there.

## Questions patients ask

**Does a bone graft hurt?**

Most grafts in the mouth are placed under local anaesthetic, so the area is numb during the procedure. Soreness, swelling and bruising are common for a while afterwards, and the dentist advises on pain relief. Grafts that take bone from the hip are done under general anaesthetic in hospital.

**Where does the graft material come from?**

It can be the patient's own bone, bone from a human donor supplied by a tissue bank, treated bone mineral of animal origin (usually from cattle), or a synthetic material. Membranes can also be of human, animal (including pig) or synthetic origin. The dentist explains what is proposed, and anyone who wishes to avoid animal-derived products can raise it beforehand.

**How long is it before an implant can be placed?**

It depends on the size of the graft, where it is and how the bone heals. A small graft is sometimes placed at the same time as the implant. A larger one is usually left to heal first, and how long that takes differs from person to person.

**Will I notice anything in my sinus after a sinus lift?**

The sinus may feel full or blocked for a while, and a small nosebleed can happen. The dentist usually advises against blowing the nose hard during healing. A tear in the sinus lining and a sinus infection are possible complications, and are discussed before treatment.

**Does everyone need a graft before an implant?**

No. Many people have enough bone. Where bone is limited, a shorter or angled implant, fewer implants placed differently, a bridge or a denture may be alternatives. Which option suits depends on the scan and on the person's health and wishes.

## What this page rests on

This page rests on patient information published by NHS hospital trusts and on Cochrane systematic reviews, listed below. It is general information: whether a graft is needed, and which method would suit, can only be judged at an examination with X-rays or a scan.

General health information, not a diagnosis or a treatment recommendation for any individual.

### Sources

1. Cambridge University Hospitals NHS Foundation Trust — [Bone grafting for dental implants](https://www.cuh.nhs.uk/patient-information/bone-grafting-for-dental-implants/)
2. Cambridge University Hospitals NHS Foundation Trust — [Sinus lift procedures](https://www.cuh.nhs.uk/patient-information/sinus-lift-procedures/)
3. Guy's and St Thomas' NHS Foundation Trust — [Bone grafting for dental implants](https://www.guysandstthomas.nhs.uk/health-information/bone-grafting-dental-implants)
4. Atieh MA, et al. (2021) — [Interventions for replacing missing teeth: alveolar ridge preservation techniques for dental implant site development. Cochrane Database of Systematic Reviews](https://doi.org/10.1002/14651858.CD010176.pub3)
5. Esposito M, et al. (2014) — [Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus. Cochrane Database of Systematic Reviews](https://doi.org/10.1002/14651858.CD008397.pub2)

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