Abscess: An infection of a tooth, soft tissue, or bone.

Abutment: Tooth or teeth on either side of a missing tooth that support a fixed or removable bridge..

Acrylic resin: The plastic widely used in dentistry.

ADA Seal of Acceptance: A designation awarded to products that have met American Dental Association's criteria for safety and effectiveness and whose packaging and advertising claims are scientifically supported.

Adjustment: A modification made upon a dental prosthesis after it has been completed and inserted into the mouth.

Air abrasion/micro abrasion: A drill-free technique that blasts the tooth surface with air and an abrasive. This is a relatively new technology that may avoid the need for an anesthetic and can be used to remove tooth decay, old composite restorations and superficial stains and discolorations, and prepare a tooth surface for bonding or sealants.

Alveolar bone: The bone surrounding the root of the tooth, anchoring it in place; loss of this bone is typically associated with severe periodontal (gum) disease.

Amalgam: A common filling material used to repair cavities. The material, also known as "silver fillings," contains mercury in combination with silver, tin, copper, and sometimes zinc.

Anaerobic bacteria: Bacteria that do not need oxygen to grow; they are generally associated with periodontal disease (see below).

Analgesia: A state of pain relief; an agent for lessening pain.

Anesthesia: A type of medication that results in partial or complete elimination of pain sensation; numbing a tooth is an example of local anesthesia; general anesthesia produces partial or complete unconsciousness.

Antibiotic: A drug that stops or slows the growth of bacteria.

Antiseptic: A chemical agent that can be applied to living tissues to destroy germs.

Apex: The tip of the root of a tooth.

Apicoectomy: An apicoectomy is a procedure in which the dental practitioner opens the gum tissue near the tooth to see the underlying bone and to remove any inflamed or infected tissue. The very end of the root is also removed.

Appliance: Any removable dental restoration or orthodontic device.

Arch: A description of the alignment of the upper or lower teeth.


Baby bottle tooth decay: Decay in infants and children, most often affecting the upper front teeth, caused by sweetened liquids given and left clinging to the teeth for long periods (for example, in feeding bottles or pacifiers). Also called early childhood carries.

Bicuspid: The fourth and fifth teeth from the center of the mouth to the back of the mouth. These are the back teeth that are used for chewing; they only have two points (cusps). Adults have eight bicuspids (also called premolars), two in front of each group of molars.

Biofeedback: A relaxation technique that involves learning how to better cope with pain and stress by altering behavior, thoughts, and feelings.

Biopsy: Removal of a small piece of tissue for diagnostic examination.

Bisphosphonates (also called diphosphonates) are a class of drugs that prevent the loss of bone mass, used to treat osteoporosis and similar diseases. They are called bisphosphonates because they have two phosphonate (PO3) groups and are similar in structure to pyrophosphate.

Bite: Relationship of the upper and lower teeth upon closure (occlusion).

Bite-wing: A single X-ray that shows teeth (from crown to about the level of the supporting bone) in a select area on the same film.

Bleaching: Chemical or laser treatment of natural teeth that uses peroxide to produce the whitening effect.

Bonding: The covering of a tooth surface with a tooth-colored composite to repair and/or change the color or shape of a tooth, for instance, due to stain or damage.

Bone resorption: Decrease in the amount of bone supporting the roots of teeth; a common result of periodontal (gum) disease.

Braces: Devices (bands, wires, ceramic appliances) put in place by orthodontists to gradually reposition teeth to a more favorable alignment.

Bridge: Stationary dental prosthesis (appliance) fixed to teeth adjacent to a space; replaces one or more missing teeth, cemented or bonded to supporting teeth or implants adjacent to the space. Also called a fixed partial denture.

Bruxism: Grinding or gnashing of the teeth, most commonly during sleep.

Burning mouth syndrome (BMS): Or Glossodynia (also known as "Burning tongue and "Orodynia") is a condition characterized by a burning or tingling sensation on the lips, tongue, or entire mouth. Typically, there are no visual signs like discoloration that help the diagnosis. BMD is defined as the presence of a burning sensation in the mouth and/or tongue (almost always bilateral) without the presence of any discoloration, ulcers, or other visual anomalies in the oral cavity.


Calcium: An element needed for the development of healthy teeth, bones, and nerves.

Calculus: Hard, calcium-like deposits that form on teeth due to inadequate plaque control, often stained yellow or brown. Also called "tartar."

Candida is a genus of yeasts. Many species are harmless commensals or endosymbiosis of hosts including humans, but other species, or harmless species in the wrong location, can cause disease. Candida albicans can cause infections (candidiasis or thrush) in humans and other animals, especially in immunocompromised patients.

Canker sore: Sores or small shallow ulcers that appear in the mouth and often make eating and talking uncomfortable; they typically appear in people between the ages of 10 and 20 and last about a week in duration before disappearing.

Cap: Common term for a dental crown.

Caries: Tooth decay or "cavities."

Cementum: Hard tissue that covers the roots of teeth.

Clasp: Device that holds a removable partial denture to stationary teeth.

Cleaning: Removal of plaque and calculus (tarter) from teeth, generally above the gum line.

Cleft lip: A physical split or separation of the two sides of the upper lip that appears as a narrow opening or gap in the skin of the upper lip. This separation often extends beyond the base of the nose and includes the bones of the upper jaw and/or upper gum.

Cleft palate: A split or opening in the roof of the mouth.

Composite resin filling: Tooth-colored restorative material composed of plastic with small glass or ceramic particles; usually "cured" or hardened with filtered light or chemical catalyst. An alternative to silver amalgam fillings.

Conventional denture: A denture that is ready for placement in the mouth about eight to 12 weeks after the teeth have been removed.

Cosmetic (aesthetic) dentistry: A branch of dentistry under which treatments are performed to enhance the color and shape of teeth.

Crown: (1) the portion of a tooth above the gum line that is covered by enamel; (2) dental restoration covering all or most of the natural tooth; the artificial cap can be made of porcelain, composite, or metal and is cemented on top of the damaged tooth.

Cuspids: The third tooth from the center of the mouth to the back of the mouth. These are the front teeth that have one rounded or pointed edge used for biting. Also known as canines

Cusps: The high points on the chewing surfaces of the back teeth.

Cyst: An abnormal sac containing gas, fluid, or a semisolid material.


DDS: Doctor of Dental Surgery -- equivalent to DMD, Doctor of Dental Medicine.

Decay: Destruction of tooth structure caused by toxins produced by bacteria.

Deciduous teeth: Commonly called "baby teeth" or primary teeth; the first set of (usually) 20 teeth.

Demineralization: Loss of mineral from tooth enamel just below the surface in a carious lesion; usually appears as a white area on the tooth surface.

Dental implant: Is a "root" device, usually made of titanium, used in dentistry to support restorations that resemble a tooth or group of teeth to replace missing teeth.

Dentin: Inner layer of tooth structure, immediately under the surface enamel.

Denture: A removable replacement of artificial teeth for missing natural teeth and surrounding tissues. Two types of dentures are available -- complete and partial. Complete dentures are used when all the teeth are missing, while partial dentures are used when some natural teeth remain.

DMD: Doctor of Medical Dentistry; equivalent to DDS, Doctor of Dental Surgery.

Dry mouth: A condition in which the flow of saliva is reduced and there is not enough saliva to keep the mouth moist. Dry mouth can be the result of certain medications (such as antihistamines and decongestants), certain diseases (such as Sjögren's syndrome, HIV/AIDS, Alzheimer's disease, diabetes), certain medical treatments (such as head and neck radiation), as well as nerve damage, dehydration, tobacco use, and surgical removal of the salivary glands. Also called xerostomia.

Dry socket: A common complication that occurs when either a blood clot has failed to form in an extracted tooth socket or else the blood clot that did form has been dislodged.


Edentulous: Having no teeth.

Enamel: The hard, mineralized material that covers the outside portion of the tooth that lies above the gum line (the crown).

Endodontics: A field of dentistry concerned with the biology and pathology of the dental pulp and root tissues of the tooth and with the prevention, diagnosis, and treatment of diseases and injuries of these tissues. A root canal is a commonly performed endodontic procedure.

Endodontist: A dental specialist concerned with the causes, diagnosis, prevention, and treatment of diseases and injuries of the human dental pulp or the nerve of the tooth.

Eruption: The emergence of the tooth from its position in the jaw.

Exposure: Surgical exposure of an unerupted tooth

Extraction: Removal of a tooth.


Filling: Restoration of lost tooth structure with metal, porcelain, or resin materials.

Fistula: Channel emanating pus from an infection site; a gum boil.

Flap surgery: Lifting of gum tissue to expose and clean underlying tooth and bone structures.

Flossing: A thread-like material used to clean between the contact areas of teeth; part of a good daily oral hygiene plan.

Fluoride: A mineral that helps strengthen teeth enamel making teeth less susceptible to decay. Fluoride is ingested through food or water, is available in most toothpastes, or can be applied as a gel or liquid to the surface of teeth by a dentist

Fluorosis: Discoloration of the enamel due to too much fluoride ingestion (greater than one part per million) into the bloodstream, also called enamel mottling.

Frenectomy: Is the removal of a frenulum, a small fold of tissue that prevents an organ in the body from moving too far. It can refer to frenula in several places on the human body. It is related to frenuloplasty, a surgical alteration in a frenulum. Done mostly fororthodonticpurposes.

FUE (Follicular Unit Extraction): is a method of extracting, or “harvesting,” donor hair in a follicular unit hair transplant procedure. In FUE, an instrument is used to make a small, circular incision in the skin around a follicular unit, separating it from the surrounding tissue.


General dentist: The primary care dental provider. This dentist diagnoses, treats, and manages overall oral health care needs, including gum care, root canals, fillings, crowns, veneers, bridges, and preventive education.

Gingiva: The soft tissue that surrounds the base of the teeth; the pink tissue around the teeth.

Gingivectomy: Surgical removal of gum tissue.

Gingivitis: Inflamed, swollen, and reddish gum tissue that may bleed easily when touched or brushed. It is the first step in a series of events that begins with plaque build up in the mouth and may end -- if not properly treated -- with periodontitis and tooth loss due to destruction of the tissue that surrounds and supports the teeth.

Gingivoplasty: A procedure performed by periodontists to reshape the gum tissue.

Gold fillings: An alternative to silver amalgam fillings.

Gum recession: Exposure of dental roots due to shrinkage of the gums as a result of abrasion, periodontal disease, or surgery.

Guttapercha: Material used in the filling of root canals.


Halitosis: Bad breath of oral or gastrointestinal origin.

Handpiece: The instrument used to hold and revolve burs in dental operations.

Hard palate: The bony front portion of the roof of the mouth.

Hygienist: S licensed, auxiliary dental professional who is both an oral health educator and clinician who uses preventive, therapeutic, and educational methods to control oral disease.

Hypersensitivity: A sharp, sudden painful reaction in teeth when exposed to hot, cold, sweet, sour, salty, chemical, or mechanical stimuli.


Immediate denture: A complete or partial denture that is made in advance and can be positioned as soon as the natural teeth are removed.

Impacted tooth: A tooth that is partially or completely blocked from erupting through the surface of the gum. An impacted tooth may push other teeth together or damage the bony structures supporting the adjacent tooth. Often times, impacted teeth must be surgically removed.

Implant: A metal rod (usually made of titanium) that is surgically placed into the upper or lower jawbone where a tooth is missing; it serves as the tooth root and anchor for the crown, bridge, or denture that is placed over it.

Impression: Mold made of the teeth and soft tissues.

Incision and drainage: Surgical incision of an abscess to drain pus.

Incisors: Four upper and four lower front teeth, excluding the cuspids (canine teeth). These teeth are used primarily for biting and cutting.

Inlay: Similar to a filling but the entire work lies within the cusps (bumps) on the chewing surface of the tooth.


Jawbone: The hard bone that supports the face and includes alveolar bone, which anchors the teeth.


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

Keratinized gingiva: The oral surface of the gingiva extending from the mucogingival junction to the gingival margin. In gingival health, the coronal portion of the sulcular epithelium may also be karatinized.


Leukoplakia: A white or gray patch that develops on the tongue or the inside of the cheek. It is the mouth's reaction to chronic irritation of the mucous membranes of the mouth.


Malocclusion: "bad bite" or misalignment of the teeth or jaws.

Mandible: The lower jaw.

Mandibular advancement device: A mandibular splint or mandibular advancement splint (MAS) is a device worn in the mouth that is used to treat obstructive sleep apnea (OSA) and snoring. These devices are also known as "mandibular advancement devices," "sleep apnea oral appliances," and "sleep apnea mouth guards."

Maxilla: The upper jaw.

Mercury: A metal component of amalgam fillings.

Molars: Three back teeth in each dental quadrant used for grinding food.

Mouth guard: A soft-fitted device that is inserted into the mouth and worn over the teeth to protect them against impact or injury.

Mucocele: is a clinical term that refers to two related phenomena: mucus extravasation phenomenon, and mucus retention cyst. The former is a swelling of connective tissue consisting of collected mucin due to a ruptured salivary gland duct usually caused by local trauma, in the case of mucus extravasation phenomenon, and an obstructed or ruptured salivary duct (Parotid duct) in the case of a mucus retention cyst. Inflammation of sinuses can also cause this condition. The mucocele has a bluish translucent color, and is more commonly found in children and young adults.

Muscle relaxant: A type of medication often prescribed to reduce stress.


Nerve: Tissue that conveys sensation, temperature, and position information to the brain.

Nerve (root) canal: Dental pulp; the internal chamber of a tooth where the nerves and blood vessels pass.

Night guard: A removable acrylic appliance that fits over the upper and lower teeth used to prevent wear and temporomandibular damage caused by grinding or gnashing of the teeth during sleep.

Nitrous oxide: A gas (also called laughing gas) used to reduce patient anxiety.

NSAID: Anonsteroidal anti-inflammatory drug, often used as a dental analgesic.


Occlusal X-rays: An X-ray showing full tooth development and placement. Each X-ray reveals the entire arch of teeth in either the upper or lower jaw.

Occlusion: The relationship of the upper and lower teeth when the mouth is closed.

Onlay: A type of restoration (filling) made of metal, porcelain, or acrylic that is more extensive than an inlay in that it covers one or more cusps. Onlays are sometimes called partial crowns.

Oral cavity: The mouth.

Oral and maxillofacial radiologist: An oral health care provider who specializes in the production and interpretation of all types of X-ray images and data that are used in the diagnosis and management of diseases, disorders, and conditions of the oral and maxillofacial region.

Oral and maxillofacial surgery: Surgical procedures on the mouth including extractions, removal of cysts or tumors, and repair of fractured jaws.

Oral hygiene: Process of maintaining cleanliness of the teeth and related structures.

Oral medicine: The specialty of dentistry that provides for the care of the medically complex patient through the integration of medicine and oral health care.

Oral pathologist: The oral health care provider who studies the causes of diseases that alter or affect the oral structures (teeth, lips, cheeks, jaws) as well as parts of the face and neck.

Oral surgeon: The oral health care provider who performs many types of surgical procedures in and around the entire face, mouth, and jaw area.

Orthodontics: Dental specialty that using braces, retainers, and other dental devices to treat misalignment of teeth, restoring them to proper functioning.

Orthodontist: The oral health provider who specializes in diagnosis, prevention, interception, and treatment of malocclusions, or "bad bites," of the teeth and surrounding structures. This is the specialist whose responsibility it is to straighten teeth by movement of the teeth through bone by the use of bands, wires, braces, and other fixed or removable corrective appliances or retainers.

Overbite: An excessive protrusion of the upper jaw resulting in a vertical overlap of the front teeth.

Overjet: An excessive protrusion of the upper jaw resulting in a horizontal overlap of the front teeth.

Overdenture: Denture that fits over residual roots or dental implants.


Palate: Hard and soft tissue forming the roof of the mouth.

Panoramic X-ray: A type of X-ray that shows a complete two dimensional representation of all the teeth in the mouth. This X-rays also shows the relationship of the teeth to the jaws and the jaws to the head.

Partial denture: A removable appliance that replaces some of the teeth in either the upper or lower jaw.

Pathology: Study of disease.

Pedodontics or pediatric dentistry: Dental specialty focusing on treatment of infants, children, and young adults.

Pedodontist/pediatric dentist: The oral health care provider who specializes in the diagnosis and treatment of the dental problems of children from infancy to early adulthood.

Periapical: Region at the end of the roots of teeth.

Periapical X-rays: X-rays providing complete side views from the roots to the crowns of the teeth.

Pericoronitis: Is a common problem in young adults with partial tooth impactions. It usually occurs within 15 to 24 years of age as it is when the third molars start erupting. It occurs when the tissue around the wisdom tooth has become inflamed because bacteria have invaded the area

Periodontal ligament: The connective tissue that surrounds the tooth (specifically covering the cementum) and connects the tooth to the jawbone, holding it in place.

Periodontist: The dental specialist who specializes in diagnosing, treating, and preventing diseases of the soft tissues of the mouth (the gums) and the supporting structures (bones) of the teeth (both natural and man-made teeth).

Periodontitis: A more advanced stage of periodontal disease in which the inner layer of the gum and bone pull away from the teeth and form pockets and alveolar bone is destroyed.

Periodontium: The tissue that lines the socket into which the root of the tooth fits.

Permanent teeth: The teeth that replace the deciduous or primary teeth -- also called baby teeth. There are (usually) 32 adult teeth in a complete dentition.

Plaque: A colorless, sticky film composed of undigested food particles mixed with saliva and bacteria that constantly forms on the teeth. Plaque left alone eventually turns in to tartar or calculus and is the main factor in causing dental caries and periodontal disease.

Pontic: A replacement tooth mounted on a fixed or removal appliance.

Porcelain: A tooth-colored, sand-like material; much like enamel in appearance.

Porcelain crown: All porcelain restoration covering the coronal portion of tooth (above the gum line).

Porcelain fused to metal (PFM) crown: Restoration with metal caping (for strength) covered by porcelain (for appearance).

Porcelain inlay or onlay: Tooth-colored restoration made of porcelain, cemented or bonded in place.

Post: Thin metal rod inserted into the root of a tooth after root canal therapy; provides retention for a capping that replaces lost tooth structure.

Pregnancy gingivitis: Gingivitis that develops during pregnancy. The hormonal changes that occur during pregnancy -- especially the increased level of progesterone -- may make it easier for certain gingivitis-causing bacteria to grow as well as make gum tissue more sensitive to plaque and exaggerate the body's response to the toxins (poisons) that result from plaque

Pregnancy tumors: An extreme inflammatory reaction to a local irritation (such as food particles or plaque) that occurs in up to 10% of pregnant women and often in women who also have pregnancy gingivitis. Pregnancy tumors appear on inflamed gum tissue as large lumps with deep red pinpoint markings on it, usually near the upper gum line. The red lump glistens, may bleed and crust over, and can make eating and speaking difficult and cause discomfort.

Primary teeth: The first set of 20 temporary teeth. Also called baby teeth, the primary dentition, or deciduous teeth, normally fall out one by one between 6 and 12 years of age.

Prophylaxis: The cleaning of the teeth for the prevention of periodontal disease and tooth decay.

Prosthetics: A fixed or removable appliance used to replace missing teeth (for example, bridges, partials, and dentures).

Prosthodontist: A dental specialist who is skilled in restoring or replacing teeth with fixed or removable prostheses (appliances), maintaining proper occlusion; treats facial deformities with artificial prostheses such as eyes, ears, and noses.

Pulp: The living part of the tooth, located inside the dentin. Pulp contains the nerve tissue and blood vessels that supply nutrients to the tooth.


Quadrant: One of the four sections into which the dental arches can be divided: begins at the midline of the arch and extends distally (back) to the last tooth.


Radiographic: Refers to X-rays.

Radio wave therapy: A therapy involving the use of low level electrical stimulation to increase blood flow and provide pain relief. In dentistry, this is one type of therapy that can be applied to the joint of individuals with temporomandibular disorder.

Ranula: Is a type of mucocele found on the floor of the mouth. Ranulas present as a swelling of connective tissue consisting of collected mucin from a ruptured salivary gland duct, which is usually caused by local trauma.

Recontouring: A procedure in which small amounts of tooth enamel are removed to change a tooth's length, shape, or surface.Also called odontoplasty, enameloplasty, stripping, or slenderizing.

Remineralization: Redeposition or replacement of the tooth's minerals into a demineralized (previously decayed) lesion. This reverses the decay process, and is enhanced by the presence of topical fluoride.

Restorations: Any replacement for lost tooth structure or teeth; for example, bridges, dentures, fillings, crowns, and implants.

Retainer: A removable appliance used to maintain teeth in a given position (usually worn at night).

Root: Tooth structure that connects the tooth to the jaw.

Root canal therapy: Procedure used to save an abscessed tooth in which the pulp chamber is cleaned out, disinfected, and filled with a permanent filling.

Rubber dam: Soft latex or vinyl sheet used to establish isolation of one or more teeth from contamination by oral fluids and to keep materials from falling to the back of the throat.


Saliva: Clear lubricating fluid in the mouth containing water, enzymes, bacteria, mucus, viruses, blood cells and undigested food particles.

Salivary glands: Glands located under tongue and in cheeks that produce saliva.

Scaling and root planing: A deep-cleaning, nonsurgical procedure whereby plaque and tartar from above and below the gum line are scraped away (scaling) and rough spots on the tooth root are made smooth (planing).

Sealants: A thin, clear or white resin substance that is applied to the biting surfaces of teeth to prevent decay.

Sedative: A type of medication used to reduce pain and anxiety, and create a state of relaxation.

Sleep apnea: Is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. Each pause in breathing, called an apnea, can last from a few seconds to minutes, and may occur 5 to 30 times or more an hour.Similarly, each abnormally low breathing event is called a hypopnea. Sleep apnea is diagnosed with an overnight sleep test called a polysomnogram, or "sleep study".

Sleep apnea oral appliance: A mandibular splint or mandibular advancement splint (MAS) is a device worn in the mouth that is used to treat obstructive sleep apnea (OSA) and snoring. These devices are also known as "mandibular advancement devices," "sleep apnea oral appliances," and "sleep apnea mouth guards."

Soft palate: The back one-third of the roof of the mouth composed of soft tissue.

Space maintainer: Dental device that holds the space lost through premature loss of baby teeth.

Stains: Can be either extrinsic or intrinsic. Extrinsic stain is located on the outside of the tooth surface originating from external substances such as tobacco, coffee, tea, or food; usually removed by polishing the teeth with an abrasive prophylaxis paste. Intrinsic stain originates from the ingestion of certain materials or chemical substances during tooth development, or from the presence of caries. This stain is permanent and cannot be removed.

Stomatitis: An inflammation of the tissue underlying a denture. Ill-fitting dentures, poor dental hygiene, or a buildup of the fungus Candida albicans cause the condition.

Supernumerary tooth: An extra tooth.


Tartar: Common term for dental calculus, a hard deposit that adheres to teeth; produces rough surface that attracts plaque.

Teething: Baby teeth pushing through the gums.

Temporomandibular disorder (TMD)/temporomandibular joint (TMJ): The term given to a problem that concerns the muscles and joint that connect the lower jaw with the skull. The condition is characterized by facial pain and restricted ability to open or move the jaw. It is often accompanied by a clicking or popping sound when the jaw is opened or closed.

Thrush: An infection in the mouth caused by the fungus Candida.

Tooth whitening: A chemical or laser process to lighten the color of teeth.

Topical anesthetic: Ointment that produces mild anesthesia when applied to a soft tissue surface.

Transcutaneous electrical nerve stimulation (TENS): A therapy that uses low-level electrical currents to provide pain relief. In dentistry, TENS is one type of therapy that can be used to relax the jaw joint and facial muscles.

Transplant: Placing a natural tooth in the empty socket of another tooth.

Trauma: Injury caused by external force, chemical, temperature extremes, or poor tooth alignment.

Trigger-point injections: A method of relieving pain whereby pain medication or anesthesia is injected into tender muscles called "trigger points." In dentistry, this is can be used in individuals with temporomandibular disorders.


Ultrasound: A treatment in which deep heat is applied to an affected area to relieve soreness or improve mobility. In dentistry, ultrasound can be used to treat temporomandibular disorders.

Underbite: When the lower jaw protrudes forward causing the lower jaw and teeth to extend out beyond the upper teeth.

Unerupted tooth: A tooth that has not pushed through the gum and assumed its correct position in the dental arch


Veneer: A thin, custom-made shell of tooth-colored plastic or porcelain that are bonded directly to the front side of natural teeth to improve their appearance -- for example, to replace lost tooth structure, close spaces, straighten teeth, or change color and/or shape.

Voxel (volumetric pixel or Volumetric Picture Element) is a volume element, representing a value on a regular grid in three dimensional space. Voxels are frequently used in the visualization and analysis of medical and scientific data. Some volumetric displays use voxels to describe their resolution. For example, a display might be able to show 512×512×512 voxels.


Wisdom teeth: Third (last) molars that usually erupt at age 18-25.


Xerostomia: Dry mouth or decrease in the production of saliva.

X-rays: High frequency light (or radiation) that penetrates different substances with different rates and absorption. In dentistry, there are typically four types of X-rays: periapical, bite-wing, occlusal, and panoramic.


Yeast: A general term for a fungus occuring as a unicellular, nucleated organism that usually reproduces by budding. Some yeasts may preporoduce by fission, many producing mycelia or pseudomycelia.


Zygomatic bone: Quadrangular bone on either side of the face that forms the cheek prominence.