Tooth loss is associated with resorption of the supporting bone. In the first three years following extraction, bone resorption causes a 40-60% decrease in its width. Bone resorption occurs at the expense of the outer plate of bone reducing the width of bone. Then overtime the height of bone is reduced. This becomes critical for anterior implants where ideal esthetics, phonetics and function is desired. Following tooth extraction in the upper jaw, the maxillary sinus floor expands, further decreasing the available bone to place implants in the posterior maxilla. The Inferior Alveolar Nerve courses through the mandible and may limit the length of implant that can be placed.
This often leaves a condition in which there is poor quality and quantity of bone suitable for placement of dental implants. In these situations, most patients are not candidates for placement of dental implants. Today, we have the ability to grow bone where needed. This not only gives us the opportunity to place implants of proper length and width, it also gives us a chance to restore functionality and esthetic appearance. If the bone is too thin or too short it must be replaced so an implant can be placed in the precise position of the tooth.
Bone Grafting can be used as a socket preservation procedure when it is placed following extraction of a tooth or to augment an atrophied or resorbed site.
The maxillary sinuses are air-filled cavities located in the cheekbones just below the eyes
Tooth loss below the sinus leads to bone loss, and over time the sinus expands into the area previously occupied by bone and teeth
A dental implant placed into the inadequate bone fails because there isn't enough stability to withstand forces of biting and chewing.
Dental implants need bone to hold them in place. When the sinus wall is very thin, it is impossible to place dental implants in this bone. There is a solution and it's called a sinus bone graft or sinus lift. In this common procedure we enter the sinus from where the upper teeth used to be. The sinus membrane is then lifted upward and bone/bone substitutes are inserted into the sinus. If enough bone between the upper jaw ridge and the bottom of the sinus is available to stabilize the implant well, sinus augmentations and implant placement can often be performed as a single procedure. If the bone is very thin, the sinus bone graft will have to be performed first, and then the graft will have to mature for a few months, depending upon the type of graft material used. Once the graft has matured, the implants can be placed
The sinus graft makes it possible for many patients to have dental implants when years ago there was no other option other than wearing loose dentures.
Implants placed simultaneously with sinus lift and bone grafting when sufficient bone to stabilise the implants is available.
Drawing shows that, after incision, gums in the upper jaw have been reflected back to expose overlying maxillary sinus (arrowheads). Hole have been drilled to cut a window (arrows) in bone.
Cross-sectional (lateral) view of maxillary sinus. Note that bone flap created by osteotomy has been pushed inward with maxillary sinus membrane,
Sinus membrane displaced inward and space packed with bone graft
Bone graft fills space created by inward displacement of osteotomy and sinus membrane
A second technique used to lift the sinus is called an osteotome sinus lift. This type of sinus lift is performed when there is enough bone to place a stable implant but 1-3mm of lifting is needed in order to prevent puncturing the sinus membrane. A hole is drilled and implant site prepared in the area where the implant is to be placed without going into the sinus membrane. Before inserting the implant, bone is placed into the hole and an instrument used to place gentle pressure on the bone which acts like a hydraulic jack to lift the bone, which in turn lifts the membrane. This is repeated several times with the implant itself used as the final instrument to lift the bone and membrane when placed. Sinus lifts (augmentation) have been shown to greatly increase your chances for successful implants that can last for years to come.
perfect planning for perfect teeth
Are you looking forward to have beautiful and functional teeth with minimally invasive procedures and in few dental appointments?
Sounds too good to be true but with NobelGuide™ this is a possibility.NobelGuide™ is a revolutionary treatment planning and surgical implementation system enabling the transfer of extra oral planning into the mouth with unrivaled accuracy and ease. The technique uses specific software that shows the exact position and depth of the implants before surgery.
This information is used to produce a surgical template which guides the successful placement of implants in predetermined positions. With NobelGuide™ the placing of the implant, abutment and restorative crown or bridge is simultaneous.
In practice, this means beautiful teeth for your patients in just one visit.
An accurate fitting denture is made to determine the exact position of the new teeth. With the radiographic markers attached to the denture, A CT Scan of the jaw bone is done. Information gathered by the CTscan is fed into the NobelGuide software to create a 3D model of the jaw bone. This information is used to determine the number, size and position of the implants to be placed in the jaw bone. This information is used to determine the number, size and position of the implants to be placed in the jaw bone
In the dental office, the patient comes in for a one-hour surgery to secure the new set of teeth. The patient is given only local anesthesia to numb the mouth. The implants are permanent and do not need to be replaced.
Ridge ExpansionThe technique is used to widen the bone width when the ridge is too thin to accommodate the dental implants.
In this procedure, the bony ridge of the jaw is literally expanded by mechanical. This bone expansion may be done at the same time the implants are placed or sometimes as a separate procedure. If it is done in two stages, usually only 3-4 weeks of bone healing is all that is necessary.
Nerve-repositioning: This is the least used procedure. This procedure is limited to the lower jaw in the area of the two back molars. In cases of severe resorption of the lower jaw, the inferior alveolar nerve, which runs within the body of the lower jaw and gives feeling to the lower lip and chin, comes near the superior border of the jaw. Therefore to make room for placement of dental implants, the nerve need to be lateralized.
The procedure may be combined with simultaneous implant placement or may be done earlier depending on the case.
This procedure is usually associated with some postoperative numbness in the lower jaw and lip (which recovers with time) and therefore opted for when no other option is available.
Cases of extreme resorption of jaw bone may require major bone grafting. Bone Grafting will help to place larger diameter implants in ideal locations that are stable and serviceable for a long time. It also helps to establish normal volume and dimensions of bone for ideal esthetics, lip support and phonetics.
Bone grafting materials can be derived from various sources
Bone grafting can repair implant sites with inadequate bone structure due to previous extractions, gum disease or injuries. In addition, special membranes may be utilized that dissolve under the gum and protect the bone graft and encourage bone regeneration. This is called guided bone regeneration or guided tissue regeneration.