dental implant and bone grafting procedure

Bone graft procedures before implant dental placement

It is a natural phenomenon that after teeth have been removed the bone that once supported them slowly resorbs away. This occurs faster when prolonged gum problems have been present or poorly fitting dentures are being worn. The result is that there is sometimes not enough bone to support implants.

When there is not enough bone present, it may be necessary to create new bone to fill in missing areas allowing dental implants to be fitted. A variety of techniques are available to do this and these are referred to as bone grafting.

The bone used in these situations may be specially treated donor material from a ‘Bone Bank’, a synthetic substitute, or grafted from areas in the mouth where there is some spare. In special cases where larger amounts of bone are needed it is possible to graft bone from other places such as the hip or shin to the deficient area of the mouth. The area from which the bone is taken will regrow naturally.

Animation showing bone loss due to missing teeth

Bone grafting and duration of implant treatment.

Where the clinical conditions indicate that bone grafting is required to increase the amount of bone into which implants are placed it will generally increase the time taken to complete the treatment. Under routine circumstances where no bone grafting is required the implants are commonly ready to begin function between 3 and 6 months later. If the bone grafting can be undertaken at the same time that implants are placed, treatment is more likely to take 6 to 12 months. Where implant placement must be delayed until after maturation on the bone graft, overall treatment may take 12 to 18 months.

Guided tissue regeneration

A technique called ‘guided tissue regeneration’ has also shown considerable success where the amount of bone at the intended implant site is less than ideal. When a tooth is removed the hole in the gum remains for the first few weeks. Anyone who has lost a tooth of had an extraction knows that this generally heals uneventfully, and eventually you cannot tell where the tooth was.

The basic principle behind ‘guided tissue regeneration’ is that placing a special membrane over the extraction socket creates a layer above which the fast growing soft tissue cells are prevented from entering the bony socket. This allows the slower bone cells present beneath the membrane the extra time they need to fill the socket without competition for the soft tissues to occupy the same space.

The purpose of sinus augmentation

It is very common to find that the softer bone in the area above the upper back teeth (molars and sometimes premolars) is very shallow and not suitable for normal implant procedures. To solve this problem a procedure known as a ‘sinus augmentation’ or ‘sinus lift’ was developed.

Bone may be successfully grown in the sinus spaces above your upper back teeth allowing implants to be placed. Specially treated donor bone from a ‘Bone Bank’, synthetic bone substitutes, or bone grafted from other areas of the mouth or body is placed into these empty areas. Over a period of time this is replaced by new bone thus providing a bed into which implants can be fixed.

Bone Graft – Sinus augmentation animation

 

Implant Placement and bone grafting

If the amount of bone overlying the sinus is adequate, some surgeons prefer to place the implants at the same time as the grafting procedures. Whatever type of bone is added to the sinus it must be left to mature before implants are placed or brought into function. If the implants are placed as a secondary procedure, (depending on the amount of bone being grown and the nature of the graft material used), they can be inserted after four to nine months, although occasionally it may be necessary to wait longer.

As with other bone grafting procedures the implants are left to become firmly attached to the bone. Commonly a slightly extended healing period is chosen with an average six to nine months before a denture or crown and bridgework are fitted. However, all bone grafting is unique to each individual and this information is for guidance only.

Bone graft – Ridge augmentation animation

 

The dental implant and bone relationship

Whether you have had a bone graft procedure prior to your dental implant surgery or not there are some factors that influence the implant-bone relationship. This can be due to the bone quantity and quality. Bone has different characteristics depending on its location within the body. The diameter of the drilled implant site and depth of the drilled dental implant contribute to how much bone is lost surrounding the implant site. In most cases this should not concern the patient, however cheap, unrecognised dental implant systems or poor planning of the implant therapy can lead to more bone being lost and resulting problems with dental implant.