Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and which are supported by surrounding soft and hard tissues of the oral cavity.
Conventional dentures are removable, however there are many different denture designs, some which rely on bonding or clasping onto teeth or dental implants.
There are two main categories of dentures, depending on whether they are used to replace missing teeth on the mandibular arch or the maxillary arch.
A bridge, also known as a fixed partial denture, is a dental restoration used to replace a missing tooth by joining permanently to adjacent teeth or dental implants.
Types of bridges may vary, depending upon how they are fabricated and the way they anchor to the adjacent teeth. Conventionally, bridges are made using the indirect method of fabricating them in the dental laboratory.
A bridge is fabricated by reducing the teeth on either side of the missing tooth or teeth by a preparation pattern determined by the location of the teeth and by the material from which the bridge is fabricated. In other words, the abutment teeth are reduced in size to accommodate the material to be used to restore the size and shape of the original teeth in a correct alignment and contact with the opposing teeth. The dimensions of the bridge are defined by Ante’s Law: “The root surface area of the abutment teeth has to equal or surpass that of the teeth being replaced with pontics”.
The materials used for the bridges include gold, porcelain fused to metal, or in the correct situation porcelain alone. The amount and type of reduction done to the abutment teeth varies slightly with the different materials used. The recipient of such a bridge must be careful to clean well under this prosthesis.
When restoring an edentulous space with a fixed partial denture that will crown the teeth adjacent to the space and bridge the gap with a pontic, or “dummy tooth”, the restoration is referred to as a bridge. Besides all of the preceding information that concerns single-unit crowns, bridges possess a few additional considerations when it comes to case selection and treatment planning, tooth preparation and restoration fabrication.
A crown is a type of dental restoration which completely caps or encircles a tooth or dental implant. Crowns are often needed when a large cavity threatens the ongoing health of a tooth.
They are typically bonded to the tooth using a dental cement. Crowns can be made from many materials, which are usually fabricated using indirect methods. Crowns are often used to improve the strength or appearance of teeth. While inarguably beneficial to dental health, the procedure and materials can be relatively expensive.
The most common method of crowning a tooth involves using a dental impression of a prepared tooth by a dentist to fabricate the crown outside of the mouth.
The crown can then be inserted at a subsequent dental appointment. Using this indirect method of tooth restoration allows use of strong restorative materials requiring time consuming fabrication methods requiring intense heat, such as casting metal or firing porcelain which would not be possible to complete inside the mouth.
Because of the expansion properties, the relatively similar material costs, and the aesthetic benefits, many patients choose to have their crown fabricated with gold.
Periodontitis is a set of inflammatory diseases affecting the periodontium, i.e., the tissues that surround and support the teeth.
Periodontitis involves progressive loss of the alveolar bone around the teeth, and if left untreated, can lead to the loosening and subsequent loss of teeth.
Periodontitis is caused by microorganisms that adhere to and grow on the tooth’s surfaces, along with an overly aggressive immune response against these microorganisms.
A diagnosis of periodontitis is established by inspecting the soft gum tissues around the teeth with a probe (i.e. a clinical exam) and by evaluating the patient’s x-ray films (i.e. a radiographic exam), to determine the amount of bone loss around the teeth.
Specialists in the treatment of periodontists are periodontists; their field is known as “periodontology” or “periodontics”.
The temporomandibular joint is the joint of the jaw and is frequently referred to as TMJ.
There are two TMJs, one on either side, working in unison. The name is derived from the two bones which form the joint: the upper temporal bone which is part of the cranium (skull), and the lower jaw bone called the mandible. The unique feature of the TMJs is the articular disc.
The disc is composed of fibrocartilagenous tissue (like the firm and flexible elastic cartilage of the ear) which is positioned between the two bones that form the joint. The TMJs are one of the few synovial joints in the human body with an articular disc, another being the sternoclavicular joint. The disc divides each joint into two.
The lower joint compartment formed by the mandible and the articular disc is involved in rotational movement—this is the initial movement of the jaw when the mouth opens. The upper joint compartment formed by the articular disk and the temporal bone is involved in translational movement—this is the secondary gliding motion of the jaw as it is opened widely.
The part of the mandible which mates to the under-surface of the disc is the condyle and the part of the temporal bone which mates to the upper surface of the disk is the glenoid (or mandibular) fossa. Pain or dysfunction of the temporomandibular joint is commonly referred to as “TMJ”, when in fact, TMJ is really the name of the joint, and Temporomandibular joint disorder (or dysfunction) is abbreviated TMD.
This term is used to refer to a group of problems involving the TMJs and the muscles, tendons, ligaments, blood vessels, and other tissues associated with them. Some practitioners might include the neck, the back and even the whole body in describing problems with the TMJs.