Tartar – mineral deposits on the teeth both above and below the gum line.  Tartar is formed when plaque hardens, and may also be referred to as calculus.

Teething – the process of baby teeth pushing through the gums.  See Tooth Eruption.

Temporomandibular Joint (TMJ) – this is the connecting hinge between the lower jaw and base of the skull (temporo, meaning temporal bone, and mandibular, meaning the lower jaw).  This is also known as the TMJ.

Temporomandibular Syndrome/Temporomandibular Joint Disorder (TMJ) – this is a condition which affects the cartilage around the temporomandibular joint (the joint between the lower jaw, or mandible, and the skull).  It may be characterized by clicking, popping, or locking, as well as pain and soreness in the jaw, neck, and shoulder muscles.

Terminal Mesial Step – the position of a vertical plane along the distal surfaces when the primary second molars are in the Class I position.

Terminal Plane – the distal surfaces of the maxillary and mandibular primary second molars that are on the same line or plane.

Third Molars – also known as wisdom teeth.  These are the upper and lower third molars found in the back of the mouth, and are almost always extracted.

Thrush – a medical condition caused when yeasts colonize in the mouth, creating a series of painful, tender lesions, and a creamy coating which superficially resembles cottage cheese.

TMD – Temporomandibular Disorder; a problem with the joint that connects the lower jaw with the skull.  This condition is typically associated with a popping sound and pain in the joint.

Toothache – pain and discomfort localized around a tooth. Most toothaches are caused by cavities or tooth decay, but they can also be a result of gum disease or other issues.

Tooth Abscess – an abscess that occurs inside of a tooth and in the surrounding tissue, also known as a periodontal or periapical abscess.

Tooth Eruption – the process through which teeth push through the gums.  This will occur twice in a person’s lifetime, once when the primary teeth come in, and once when the adult teeth come in.

Topical – a treatment applied directly to an infected area.

Transcutaneous Electrical Nerve Stimulation – more commonly referred to as TENS; this is a form of electronic muscle therapy provided for pain relief.

Transverse Ridge – a linear elevation that crosses a surface, usually the occlusal (bite) surface.

Triangular Ridge – a linear elevation that forms a triangle.

Trifurcation – forked or divided into three parts.

Tuberosity – a large, rounded projection found on the lower arch, also called a retromolar pad (an area behind the wisdom teeth).