Fibronectin is a glycoprotein of high-molecular weight (~440kDa) and is part of the extracellular matrix. It binds to membrane-spanning receptor proteins called integrins before then binding to extracellular matrix components such as collagen, fibrin, and heparan sulfate proteoglycans (syndecans). Fibronectin helps in the promotion of cellular migration and adhesion and is involved in the accumulation of platelets to the site of a wound. Fibronectin is therefore an essential part of the wound healing process and is also a critical part in cell differentiation in the development of vertebrates. In dental applications and implant surgeries, fibronectin can positively affect fibroblast attachment in the gingiva and prevent inflammation-driven breakdown of the tissues around the implant. Though a variety of scientific studies have been conducted on the efficacy of applying fibronectin directly to the wound site following a dental procedure, the results have been inconclusive. However, the wound-healing role of fibronectin naturally present in the body is indisputable.
Fibrous connective tissue is composed of parallel bundles of collagen fibers. It is found in the dermis, tendons, and ligaments and can also be referred to as dense connective tissue. In dental applications, fibrous connective tissue makes up an important part of the oral anatomy and has the ability to interact with dental implants. Fibrous connective tissue has been found to attach to dental implants at specific locations superior to the crestal bone and inferior to the junctional epithelium. The attachment of the connective tissue to the implant seems to strengthen previous findings about the long-term success of implants and their relationship with the surrounding tissues. Since one of the major roles of fibrous connective tissue is to provide support to surrounding bone, tissue, and organs, its re-growth at implant sites means the implant may have some of the same structural support as natural teeth.
Fibrous encapsulation refers to the layer of fibrous connective tissue that is formed between a dental implant and surrounding bone. Following implant surgery, the implant should begin to integrate with the nearby hard and soft tissues of the mouth. Though osseointegration is frequently written of post implant, the integration that takes place between the implant components and the connective tissues at the site is also important to implant stability and longevity. Fibrous connective tissue has several functions, one of the primary being to provide support to surrounding tissues. Therefore, the successful re-growth of fibrous connective tissue in developing a fibrous encapsulation between the bone and the implant provides additional support to the dental prosthesis and increases the likelihood of long-term retention. Not only does this connective tissue anchor the implant more securely to the bone but to the surrounding teeth, tissues, and oral framework which gives the prosthesis a greater chance for success.
Fiducial markers are specialized markers that are supplemented onto the operative field prior to the imaging scan. They are used during surgery as the key reference points for the patient’s registration procedure or during surgical guide fabrication for the transfer of information from software-based planning. In dentistry, fiducial markers are used in several applications such as assisting with the creation and placement of dentures based on the unique oral anatomy of the patient. They also serve to identify specific locations for guided surgery both on a virtual level as well as in the actual patient. The use of fiducial markers in dentistry allows practitioners to correctly identify placement position for oral prostheses to ensure the correct fit and helps guide surgeons and practitioners to the precise location where an oral procedure should be performed. Fiducial markers also make the transition from virtual model to a physical model or prosthesis easier and more accurate as the software used directly reflects the patient’s exact oral anatomy.
Finite element analysis, or FEA, is a computer software method used to study stresses and strains on various mechanical parts or components. The term finite element analysis can also refer to a virtual prototyping software, often a component of computer-aided design software programs, which automatically generates the simulated mechanical loads for FEA. In dentistry, finite element analysis has been used to study the mechanical stresses of dental implants as well as the strain on surrounding bone. It has also been applied to studying the strain and stability of the structures and materials used to create dental implants and prostheses. FEA allows practitioners and analysists to create countless simulations which show the stresses present during mastication in both the bone and the implant. The overall distribution of these stresses can also be analyzed to determine if one part of the oral anatomy experiences more strain than another. The data collected can be used to create more durable implants.
A fistula is an abnormal passage or communication, usually between two internal organs or leading from an internal organ to the surface of the body. In dentistry, there are three different types:
- Oroantral fistula: An opening between the oral cavity and the maxillary sinus
- Orofacial fistula: An opening between the cutaneous surface of the face and the oral cavity
- Oronasal fistula: An opening between the nasal cavity and the oral cavity
A fistula generally develops after trauma to the mouth, due to periodontal disease, or after the loss of teeth. It collects the puss and other waste from the infection that has developed due to these issues and when full, forms a small bump. This bump often ruptures spontaneously and without treatment though dental attention is usually required as it represents the presence of an underlying infection. Treatment may include cleansing of the infected areas and antibiotics.
A fixation screw is a screw used for the stabilization of a block graft or a barrier membrane. A fixation screw can also be used to stabilize a surgical guide. A block bone graft is a procedure performed in patients that have bone defects over a large area. The replacement bone for the affected area is generally taken from the back of the jaw. Once the new bone is placed, it is secured using fixation screws which are often made of titanium. A barrier membrane is utilized following a guided bone regeneration procedure and is put in place to prevent pathogens or other cells not involved in osseointegration from invading the site of the GBR. The membrane protects the cells involved in bone growth through preventing contamination with non-related cells or microbes. It is therefore essential that this membrane be secured using fixation screws to prevent its movement or removal
A fixed prosthesis is an immovable dental prosthesis that is held into place. Technically, a single dental implant is a type of fixed prosthesis, however, the term is typically used to describe dental prosthetics that replace multiple teeth and are anchored to one or more dental implants. The fixed prosthetic may also be cemented or bonded to nearby natural teeth instead of to a dental implant. For example, a dental bridge is one of the most common types of fixed dental prostheses. A bridge is one or more false teeth that are placed in between natural teeth, either anchored to the natural teeth or an implant abutment. A fixed prosthesis that is cemented or bonded to natural teeth is a faster solution than a dental implant, however, implant-anchored prosthetics have more stability and permanence. Natural teeth must be filed down to support a cemented prosthetic, but implant-anchored fixed prostheses keep natural teeth intact.
A fixed detachable denture is a hybrid between complete dentures and dental implants. It is a type of full denture that attaches to the abutments of multiple implants across the upper or lower jaw. A fixed detachable denture is often considered a “gold standard” for complete dentures due to its many benefits. Most importantly, it preserves the underlying bone structures instead of allowing them to decrease in both quantity and quality. Fixed detachable dentures are stable and don’t move around in the mouth since they are strongly anchored to the jaw using implant technology. There is no need for denture adhesives and works like a patient’s natural teeth. Fully detachable dentures must be worn with adhesive to keep them from slipping and does a much poorer job of supporting the underlying bone and facial structures over time. Detachable dentures usually need replacement, but a fixed detachable denture typically lasts a lifetime.