The thick ridge of bone that houses the sockets for the teeth on the jawbones and holds the teeth is called the ‘alveolar process’. The tooth-bearing bones in humans are referred to as the mandible and the maxilla. The curved portion of each alveolar process is referred to as the ‘alveolar arch.’
One of the most common surgical procedures performed in oral and maxillofacial surgery is the repair of acquired or congenital alveolar defects using bone grafts. While autogenous bone grafts do require that the patient undergo a second surgical procedure, the high osteogenic potential of these grafts have made them the golden standard.
Bones consist of a hard material that is referred to as the ‘bone matrix.’ This material helps to strengthen the bones. Within this matrix are living bone cells. These cells are responsible for making and maintaining the matrix. The living bone cells in the matrix are vital to the bone rejuvenation and healing processes.
Bone morphogenetic proteins (BMPs) are growth factors that are present in the bone matrix. These BMPs can induce bone cartilage to form. It is believed that these bone morphogenetic proteins constitute a group of fundamental morphogenetic signals. In addition, BMP signaling is involved in regulating adipose tissue: various family members play different, sometimes totally opposite, roles.
Recombinant human BMPs (rhBMPs) are commonly used for oral surgery. These BMPs are approved for use by the FDA. Molecular clones of bone morphogenetic proteins have demonstrated they are a family of connected differentiation factors, each of which is capable of promoting new bone tissue formation following implantation.
Since bone resorption occurs in different dental loss cases, the presence of teeth keeps the mandibular and maxillary alveolar bone stable.
Some patients require ridge expansion before they begin their dental implant placement procedure. The bone expander (osteotome) is the instrument that is used to spread out a dental implant osteotomy. The bone expander can spread it out laterally and/or apically. This procedure can be completed with or without grafting.
The ridge splitting expansion technique is used if the height of the bone is appropriate, but its width is too narrow. The goal of this procedure is to address the narrow alveolar ridge by widening it. This expansion technique is frequently used in the anterior maxillomandibular area. Once this surgery is complete, the morphology of the lingual side is restored. Besides aesthetic results, the buccolingual side and cortical bone exert a housing effect. This improves the osseointegration process because it provides an ample supply of blood to the area.
Ridge expansion refers to the surgical, lateral widening of the residual ridge (i.e., buccolingually) using chisels and/or osteotomes. This expansion process is done to make enough room for the patient to receive a bone graft and/or a dental implant.
Once the ridge expansion process is complete, the implants can be placed. Screws are inserted, the surgeon gradually increases their thickness. While this process may take a bit longer, a good clinical outcome is likely.
Many times, implant placement involves an inadequate buccolingual width of the edentulous ridge.
A variety of treatments can be used to address inadequate buccolingual width:
- Horizontal veneer block bone graft
- Narrow implant placement
- Ridge-splitting procedure
- Horizontal guided bone regeneration (GBR)
The ridge-splitting expansion technique refers to a procedure that is used when the width of a bone is too narrow, but its height is sufficient. This procedure aims to widen the alveolar ridge. The ridge-splitting technique is frequently performed in the anterior maxillomandibular area. After surgery, the patient enjoys aesthetic results as well as the housing effect that is exerted by the cortical bone and the buccolingual side. This housing effect improves the osseointegration process by providing an adequate amount of blood to the area being addressed.
What’s a bone graft? During bone grafting, a surgeon will remove a small section of bone from one area of the body and place it in the desired area of the body. While this can be done in any area of the body depending on the patient’s needs, bone graphic has a specific place in periodontics.
It’s not uncommon for patients to experience osteonecrosis, or deterioration of the jawbone, often caused by tooth loss without replacement or advanced gum disease.
What is a bone graft procedure? During a bone graft, a periodontal surgeon will remove bone from one part of the jaw and place it onto the area where the implant is desired with the goal of building up the bone in the area where it has deteriorated too much to hold an implant. Many surgeons are now using special bone grafting material instead, and a successful procedure allows for the bone to be substantial enough to support dental implant hardware.
For a dental implant to be successful, the there not only must be enough underlying bone, but the underlying bone must be of good quality. During a patient’s initial consultation for an implant, a periodontal surgeon will evaluate the bone quality, the strength of bone, and the bone mass vs bone density with a number of diagnostic tests. The bone quality will be assessed using the BQI, or Bone Quality Index.
The bone quality index range goes from 1 to 4, with type 2 bone being considered the most successful for osseointegration of implant hardware. Type 1 bone has less vascularity than type 2, while type 3 and 4 bone is much too soft for a successful dental implant. Type 2 bone has enough vascularity for proper healing but also provides solid cortical anchorage for enough stability.
What is bone remodeling? The bone remodeling process, also called bone metabolism, is unique and occurs when exhausted bone tissue is removed from the skeleton through bone resorption. Then, new bone is formed by ossification.
When does bone remodeling occur? This process occurs throughout an individual’s life. A one-year-old child has had nearly all of their skeleton replaced by this process, although it does tend to slow with age.
The bone remodeling definition applies to all bones within the body, however, this process is of particular importance in implant dentistry. Often, the bone remodeling rate is stimulated when a dental implant is placed. However, remodeling can be helpful and is considered to be preventative against microdamage accumulated by repeated loading.
Bone scaffold tissue engineering is one of the fastest growing advancements in periodontal technology, especially with the advent of 3D printing. Current treatments for larger amounts of bone loss frequently fail at accurately replacing bone in the necessary anatomic shape and structure for the patient. With bone scaffold 3D printing, bone replacement materials can be created with a number of controls, including controlled topography, shape, and porosity.
3D printing a bone scaffold allows surgeons to customize bone grafts to the patient and are particularly helpful in cases of significant bone defects where other treatments are not as suitable. Polymeric scaffolds for bone tissue engineering open up new possibilities for surgeons and patients who may not have been good candidates for dental implants previously.
As the technology continues to be refined and become more affordable, the treatment of bone defects and the restoration of a healthy smile will be revolutionized.
A bone-anchored hearing aid (BAHA), also called a bone-anchored hearing system or bone-anchored auditory implant, is a type of surgically implanted hearing aid. Instead of amplifying sound outside the ear, a bone-anchored hearing aid will conduct sound via vibrations to the inner ear. Not all patients are good candidates for bone-anchored hearing aids since they are considered specialty hearing devices for particular types of hearing impairment. Typically, a bone-anchored hearing device is the best fit for individuals who have at least one normally-functioning inner ear. Good candidates for this type of hearing loss treatment are patients with single-sided deafness or significant middle or outer ear malformations that impact hearing. During the implantation of a BAHA, a surgeon will place a tiny titanium implant into the mastoid bone, which sits behind the ear. The implant is roughly 3-4 mm in size and is attached to an external sound processing device.
Bone to implant contact, sometimes called bone implant contact, is a term that refers to how much of the implant surface is touching bone on a microscopic level and is graded as a percentage. The type of bone plays a significant role in the percentage of bone to implant contact. In soft or medium bone, stability is typically not as good. When osseointegration occurs, stability increases and therefore the percentage of bone to implant contact increases. In dense bone, stability is typically much better and when osseointegration occurs, stability typically remains the same, or it may increase slightly but not significantly. In cases of failed implants, stability is generally low and the bone to implant contact may go down as well. After a dental implant is placed, measurements are taken to determine the level of bone to implant contact and may use this information to modify the patient treatment plan.