Hemisection: Surgical separation of a multi-rooted tooth.

Immediate Denture: Prosthesis constructed for placement immediately after removal of remaining natural teeth.

Impacted Tooth: An unerupted or partially erupted tooth that is positioned against another tooth, bone, or soft tissue so that complete eruption is unlikely.

Inlay: An indirect intracoronal restoration; a dental restoration made outside the oral cavity to correspond to the form of the prepared cavity, which is then luted into the tooth.

lntracoronal: Referring to "within" the crown of a tooth.

Intravenous: Conscious sedation (see anesthesia).

Keratin: A protein present in all cuticular structures of the body, such as hair, epidermis and horns.

Labial: Pertaining to or around the lip.

Lesion: An injury or wound; area of diseased tissue.

Lingual: Pertaining to or around the tongue; surface of the tooth directed toward the tongue; opposite of facial.

Maintenance, Periodontal: Therapy for preserving the state of health of the periodontium.

Malignant: Having the properties of dysplasia, invasion, and metastasis.

Malocclusion: Improper alignment of biting or chewing surfaces of upper and lower teeth.

Maryland Bridge: Fixed partial denture featuring conservative retainers which are resin bonded to abutments.

Maxilla: The upper jaw.

Mesial: Toward the midline of the dental arch; opposite of distal.

Molar: Teeth posterior to the premolars (bicuspids) on either side of the jaw; grinding teeth, having large crowns and broad chewing surfaces.

Mucous Membrane: Lining of the oral cavity as well as other canals and cavities of the body; also called "mucosa."