Glossary

A facebow is a special instrument used by dentists when fitting a patient for dental prosthodontics. The facebow lines up with the patient exactly and allows the dentist or periodontist to accurately measure important parts of the patient’s facial structure, like the maxillary arch and its relationship to the temporomandibular joint, and transfer that data to where it can be used to create dental prosthetics. With the rise of computer-generated dental prosthetics, the facebow has been phased out by many dentists and periodontists and is no longer used to take important measurements. However, the facebow still plays an important role in transferring functional and aesthetic components from the mouth of the patient to the dental articulator. Without a facebow, the measurements taken by a dentist or periodontist may not be as accurate as they assume. This results in having to make multiple adjustments for the esthetics and occlusions later.

A facial prosthesis is a maxillofacial or craniofacial artificial replacement for a part of the face that is missing due to:

• Traumatic injury
• Surgical intervention for carcinoma-related lesions
• Congenital defects

Facial prostheses may include the use of a prosthetic mask. They can require prosthetic nose surgery to replace the affected facial features. A prosthetic facial mask can be used to replace more than one feature as well as larger portions of missing or damaged tissue on various parts of the face. A nose prosthesis has a more limited function as it only replaces the lost or damaged nose and surrounding tissue. Such prostheses can provide confidence for those who have been affected. Prosthesis training is required for those in the medical and dental professions to ensure patients are properly fitted. Prostheses can be attached to the affected areas in a variety of ways, with some requiring stabilizing or fixing with the support of specially-designed dental implants.

A facing is more commonly known in cosmetic dentistry as a veneer. They are most commonly used to achieve a perfectly straight, white smile and can restore the look of chipped, broken, cracked, stained, and gapped teeth. Veneers are thin pieces of porcelain that are used to recreate the surface of the teeth, or the “face.” Porcelain is preferable to other materials because it has a similar density and durability as natural tooth enamel, however, some veneers are crafted from resin. Resin is a similar material to composite, or “white” fillings. Each veneer is custom made to the shape of the tooth it will be placed on and is permanently bonded to the tooth with a special procedure. Veneers are not removable and require the surface of the natural tooth to be altered to place the veneer. Patients interested in veneers should discuss the benefits and risks of permanent tooth alteration.

Unfortunately, all dental implants carry a risk of failure and a periodontist’s primary job is to use a wide variety of available tools and techniques to reduce that risk. A dental implant can include one or more teeth, either separate or joined together. They are generally made out of alloplastic materials like titanium or titanium alloy, but ceramics, bioglass, hydroxyapatite, and aluminum oxides may also be used. Osseointegration, or fusing to the bone, is the measure of success for a dental implant and what material the implant is made from and its surface texture plays a significant role in that success. Other factors for dental implant failure include but are not limited to: the location of the implant in the mouth and its placement in bone; what kind of implant screw is placed over the implant body, and the type of abutment used and how it is placed.

Like any medical procedure, dental implants can fail. The failure rate of implants is low, with only about 5-10% of patients experiencing failure. Dental implant failure can be mitigated by taking into account factors of success. The chances of implant failure are higher in patients who have gum disease, who smoke, who have insufficient or weak jawbone, or who have conditions like diabetes or rheumatoid arthritis that can impede healing. Dental implant failure can occur early after the procedure or much later. Early failure factors include an infection at the surgical site, insufficient bone to support the implant hardware, allergic reaction, poor adherence to post-op instructions, and micromovements of the hardware. Late failure factors include tissue and nerve damage at the implant site, foreign body rejection, and injury to the face or jaw that physically dislodges the implant. Signs of failure include problems chewing, pain, swelling, and gum recession.

Dental implants can fail for several reasons, including lack of osseointegration (fusion to the surrounding bone) or peri-implantitis (a post-op infection causing inflammation of the surrounding bone and gum tissues). However, dental implant failure in the long term can be caused by what is known as the fatigue phenomenon. This phenomenon was first discussed in a 1964 article called General Principles for Fatigue Testing of Metals, published in the International Organization for Standardization. The article describes the changes that can occur to metal materials when under intense “cycles” of stress or pressure for a significant period of time. This is most applicable to implant dentistry when dental professionals are considering a dental implant for a patient with bruxism. Bruxism is the repeated grinding or clenching of the teeth, usually at night, that can cause teeth to crack or cause temporomandibular joint disorder (TMJ). Patients with bruxism are more likely to experience implant failure due to fatigue.

Feldspatheic porcelain is a highly translucent, esthetic material for restorations fabricated with the traditional veneering porcelain powder and liquid brush buildup technique. When necessary, opaquer can be added by the laboratory to cover dark stain cases. Feldspathic porcelain closely resembles the color and texture of natural teeth and is a popular choice for veneers, filling gaps between teeth, and other restorative processes. This material has many benefits including minimal preparation. Patients are able to retain much of their original tooth structure which reduces the invasiveness of the procedure as well as the time required for the procedure. Feldspathic porcelain is also biocompatible, durable, and long-lasting meaning patients could potentially enjoy the effects of their replacement or restoration for years before requiring additional work. Despite the many advantages of feldspathic porcelain, it does have some issues including being the weakest of the restoration materials. When it is used, it is best on anterior teeth that still have enamel in place.

In dentistry, a fenestration is a buccal or lingual window defect of either denuded bone or soft tissue occurring over a tooth root, implant, or alveolar ridge. The term may also apply to a man-made fenestration which is created when opening a lateral window to the maxillary sinus for a sinus augmentation procedure. A naturally occurring fenestration leaves the exposed root surface in direct contact with either the alveolar mucosa or the gingiva. The condition may be caused by a variety of factors including tooth movement due to orthodontics, pathology (both endodontic and periodontal), root apex contours, and occlusal issues. Treatment of a fenestration can include guided tissue regeneration, flap surgeries, or free gingival grafting. For some patients, a bone graft may also be required. Prior to orthodontic procedures, it is important that both the root positions and the periodontium condition be evaluated to reduce the risk of fenestration.

A fibrin matrix, or fibrin-rich matrix, is a provisional matrix provided by the fibrin clot and fibronectin during the first phase of wound healing. The fibrin matrix secretes chemicals that summon monocytes, fibroblasts, and epidermal cells to the area of the body that requires healing, thus promoting the healing process. The term may also refer to a membrane-like matrix derived from autologous blood which is strong and pliable. It functions as either a standalone product or can be mixed with other biomaterials to improve wound healing and promote tissue regeneration. In dental applications, a platelet-rich fibrin matrix can be applied following a surgical procedure to speed the healing process. The fibrin matrix also has the capacity to reduce inflammation and swelling and can be used even in advanced surgical techniques. Following implant or grafting procedures, a fibrin matrix can be utilized to speed wound healing and aid in patient recovery.

A fibroblast is a type of cell found within the connective tissues that are responsible for the synthesis of collagen and ground substance. In dentistry, fibroblasts play an important role in the integration of and implant, prosthesis, or restoration. The most common types of fibroblasts involved with dental processes are gingival fibroblasts and periodontal ligament fibroblasts. They are responsible for the synthesis and organization of the collagen fibers that connect the gingiva and alveolar bone to the cementum tooth covering. In addition, fibroblasts also secrete a growth factor that stimulates tissue regeneration in dental pulp cells and the dentin-pulp complex following a tooth injury or oral surgery. Due to the tissue trauma caused by an oral surgery or implant, multiple types of cells are required to repair and regenerate the damaged tissues. Due to the responsibilities of fibroblast cells, they are among some of the most important factors in proper healing and implant success.