The goal of dental bone grafting is to create a solid base to support a dental implant, by replacing and regenerating lost bone. Implants need to be established in sound bone because of the forces of chewing. Grafting is necessary if the site for implanting lacks adequate bone; either the jawbone is not thick enough or it is too soft.
The bone grafting and implanting process
Bone grafting as a preparation for dental implantation is a multi-step process, involving numerous dental specializations spread out over time, often months. Combined with creating and placing the dental implant, numerous steps are involved.
The first step is assessing the mouth and planning the work. Assessment typically entails examination and x-rays to investigate the site and to appraise the bone quantity and condition. If the implant is being designed at this stage, then 3d imaging is also carried out and models are made. The planning can involve such specialists as a dental surgeon (specifically a maxillofacial surgeon), a periodontist (a specialist in treating bones and gums), a prosthodontist (one who designs and fits artificial teeth), and possibly an ENT (ear, nose, and throat) specialist. Sometimes some of these roles are combined in a single person.
The process also includes a review of the patient’s medical history, considering their medical conditions and medications. Often a beginning-to-end treatment plan is developed, designing an overall approach assessing a number of teeth, the condition of the jawbone involved, the condition of other teeth, and so forth.
Once a plan is in place, the steps include:
1) removing the damaged tooth
2) preparing the jawbone for surgery (If bone grafting is being done, it happens at this point).
3) healing and solidifying the graft. The healing time required after grafting depends on the type and degree of grafting. It may take several months for transplanted bone to grow enough new bone material to be suitable for dental implanting.
4) holding open the gap where the tooth was removed, possibly using a temporary spacer or denture, during healing.
The remaining steps follow the bone grafting, and constitute the work to insert a dental implant.
5) placing the implant post
6) bone growth and healing for the implant to settle and solidify. The titanium in the implant post fuses with bone (osseointegration).
7) placing the abutment. Again, healing of the abutment site may require additional surgery (minor, local anaesthetic) where the gum is opened, the abutment is attached to the implant post, and the gum is closed around but not over the abutment. Healing for a couple of weeks follows.
8) finally, placing the artificial tooth. This prosthesis can be fixed or removable.
Types of dental bone grafts
Dental bone grafts can be mandibular or maxillar:
1) mandibular: bone grafting is performed on the lower jaw (the mandible).
2) maxillar: bone grafting is performed on the upper jaw (the maxilla). Bone grafting in the upper jaw needs to avoid involving the sinuses.
Bone grafts can be horizontal or vertical. Vertical grafting adds width to the bone, while horizontal grafts add height. Horizontal grafts are generally more stable and have a better prognosis, but the nature of the bone loss dictates the type of grafting used.
Types grafting materials
Bone grafts can be created using a variety of materials: human, animal, or synthetic. Usually the dentist will choose the correct grafting material for the situation.
Autologous grafting or autograft
In this case the grafting material comes from the patient themselves. Bone or tissue is transferred from one spot (often the chin, rib, or hip) to the site for the dental graft. This method is desirable because it has a high success rate since living tissue is being grafted and so cells are kept intact.
An allograft uses material from the same species as the recipient (either a donor or a cadaver). This method is safe and easy to use, and there is a ready supply of grafting material. An additional advantage over an autologous graft is that an allograft requires one fewer procedures for the patient because no surgery is required to obtain the grafting material; as a consequence surgical time is minimized and recovery can be quicker.
A xenograft sources the grafting material from another species, usually bovine or porcine.
Alloplastic grafting is done using manufactured or synthetic material that is biocompatible and has similar characteristics to natural bone. Dentistry is making rapid advances in alloplastic grafting, and in hybrid forms of grafting.
Conditions for grafting success
For grafting to be successful, the following conditions are important:
1) The jaw has finished growing. Grafting isn’t done on immature mouths.
2) Adequate bone must be available to support grafting (and ultimately to support implants).
3) Healthy oral tissues should surround the grafting site.
4) The patient should have no health conditions that would impair healing.
5) Dentures or crowns have been ruled out as better alternatives.
6) The patient is not a smoker.
Risks involved in dental bone grafting
Bone grafting is not a minor procedure, even though it is really only preparation for a further procedure (placing a dental implant). It carries with it several risks:
2) adverse impacts on surrounding teeth and tissues
3) possible nerve damage. Pain, numbness, tingling (often transient) in teeth, gums, lips are possible.
4) sinus problems can result (although these should be anticipated and avoided).
Grafting patients may experience discomfort, swelling, or bruising of the gums and may therefore follow a diet of soft foods while their mouth heals. Because grafting (and subsequent implanting) is a multi-stage procedure, patients need consider timing events in their lives to coordinate with dental work.
Because of the complexity and variety of grafting options and procedures, it’s necessary to rely on your dentist to assess your situation and to develop an approach that addresses your grafting and dental implant needs.