By definition an Abutment is the part of a tooth or dental implant that supports a crown or bridge.

Active Eruption relates to the process of the tooth erupting or pushing upwards or downwards through the gums from its position in the jaw. The crown of the tooth becomes visible once the tooth has erupted.

Adhesive Dentistry is a branch of dentistry which mainly deals with adhesion or bonding of the adhesive material or cements to the natural substance of teeth, enamel and dentin.

Tooth bonding techniques have various clinical applications including operative and preventive dentistry as well as esthetic and pediatric dentistry, prosthodontics, and orthodontics.

As a modern science, adhesive dentistry studies the nature and strength of the adhesion to hard dental tissues (teeth).

Do you know what causes decomposition of organic materials in the soil? The answer it is an organism known as Aerobic Bacteria. It basically depends on oxygen for its growth, development and existence. It obtains energy by oxidizing substrates such as fats or sugars using oxygen.

In the nervous system, Afferent Neurons (otherwise known as sensory or receptor neurons), carry nerve impulses from receptors or sense organs toward the central nervous system.  Afferent neurons communicate with specialized interneurons. The opposite activity of direction or flow is efferent.

In the nervous system there is a "closed loop" system of sensation, decision, and reactions. This process is carried out through the activity of afferent neurons, interneurons, and efferent neurons.

A touch or painful stimulus, for example, creates a sensation in the brain only after information about the stimulus travels there via afferent nerve pathways. Afferent neurons are pseudounipolar neurons, that have a single long dendrite and a short axon, and a smooth and rounded cell body. The dendrite is structurally and functionally similar to an axon, and is myelinated; it is these axon-like dendrites that make up the afferent nerves. Just outside the spinal cord, thousands of afferent neuronal cell bodies are aggregated.

Agar's Clinical Use:

Supplied in sealed tubes to prevent the evaporation of water. The tubes are heated in boiling water (i) for 10-45 minutes. Once the impression is taken the tray is cooled with water  flowing through little pipes within the tray  to aid gel formation. The first material to set is that which is in contact with the tray since it is cooler than the tissues. Agars have been largely superseded by alginates and elastomers, although are still used for complex impressions for advanced restorative work. They are often used in labs to duplicate model because they can be reused many times.

Chemistry:

• Agar (colloid)
• Borax (strengthen gel)
• Potassium Sulphate
• Water (dispersion medium)

In its natural state it is a gel, but when heated becomes almost liquid.

Properties:

• Good surface detail
• Can be used on undercuts
• Evaporation or inhibition
• Non toxic and non irritant
• Slow setting time
• Poor tear resistance
• Adequate shelf life

Alginate Properties:

* Good surface detail

* Reaction is faster at higher temperatures

* Elastic enough to be drawn over the undercuts, but may tear over the deep undercuts

* Non toxic and non irritant

* Setting time can depend on technique

* Alginate powder is unstable on storage in presence of moisture or in warm temperatures

Advantages:

1. Non toxic and non irritant

2. Good surface detail

3. Ease of use and mix

4. Cheap and good shelf life

5. Setting time can be controlled with temperature of water used

Disadvantages:

1. Poor dimensional stability( has to be poored within ten minutes)

2. Incompatibility with some dental stones

3. Setting time very dependent on operator handling

Alveolar Bone is present just adjacent the tooth socket around the root and it gives the attachment to the periodontal ligament fibers, which are the principle fibers. These fibers which enter the bone are regarded as Sharpey’s fibers. And the bone which is the lodgement site for the fibers is called as the Bundle bone.

The supporting Alveolar Bone consist of the:

1) Cortical Bone

2) Spongy Bone

Cortical Bone contains cortical plates which have perforations in the anterior teeth, for the entry of blood vessels into the inner parts of the teeth. The cortical plates are least in the maxillary (Upper) region and the highest are seen in the molar region of the mandibular bone (lower arch)

Spongy Bone also reffered to as Spongiosa, contains trabeculae.

The spongy bone is further divided into 2 types:

Type I – Contains trabeculae which are regularly arranged in a ladder like arrangement. Type I - is seen more in the mandibular alveolar bone (lower arch)

Type II – Contains trabeculae in an irregular arrangement. Type II - is seen more in the maxillary alveolar bone (upper arch)

Alveolar Crest is often times also reffered to as the Ridge.

Alveolectomy is a surgical procedure involving the removal of the alveolar bone in order to improve the positioning or growth of the teeth or to make way for the fitting of a dental prosthesis. Alveolectomies often occur in tandem with tooth extraction procedures.

Alveolus in dentistry are sockets in the jaws in which the roots of the teeth are held in the alveolar bone of the maxilla and mandibule with the periodontal ligament. The laymen's term for dental alveoli is tooth sockets. A joint that connect the roots of the teeth and the alveolus are called gomphosis.

Alveolus are sockets in the jaws in which the roots of teeth are held in the alveolar bone of the maxilla or the mandibula with the periodontal ligament. The lay term for the dental alveoli is tooth sockets.

Amalgam is used in dentistry for a direct filling of a tooth due to a cavity.

Anaerobic Bacteria is a type of bacteria that grows in places which have little or no oxygen. Such bacteria infects deep lacerations, deep tissues, and internal organs. Infections caused by anaerobic bacteria are marked by bad-smelling pus, the formation of abscesses, and the destruction of tissue. The bacteria are most often located in the mouth, gastrointestinal tract, vagina, and on the skin.

The crown is divided into the anatomic and clinical crown. The Anatomical Crown is that portion of the tooth encased in enamel. In young people, areas of the anatomical crown are frequently buried in gingival tissue. The term clinical crown is applied to the part of the crown exposed (visible) in the mouth. 

General Anesthesia is a complete loss of consciousness within the patient accomplished through a combination of injected and inhaled drugs. This type of anesthesia is often used for highly invasive surgeries, or if the total relaxation of the patient is required. General anesthesia carries the most surgical risk because of the state of complete unconsciousness. As a result, the anesthesiologist will manage the patient carefully throughout surgery.

The exact mechanism through which general anesthesia works is unclear. It is believed that the anesthesia act on the brain to produce unconsciousness and on the nerves and spinal cord to monitored administration of additional inhaled drugs throughout the surgery.

Local Anesthesia involves injected drugs which numb a small area. Many patients have experienced a local anesthesia in the form of Novacaine, which is used in dental applications. Any small, localized procedure such as setting stitches is suitable for local anesthesia.

Regional Anesthesia is similar to local anesthesia, expect it covers a wider area of the body. Regional anesthesia works by blocking nerve impulses. Regional anesthesia allows doctors to block sensation (pain) to the entire lower body, or single limbs.

Conscious Sedation is an anesthesia practice where the patient remains conscious, but is fully relaxed, does not feel pain and will not usually remember the anesthesia. In cases where a patient is not stable enough for general anesthesia, conscious sedation may be used.
 

In dentistry, Anodontia, also called (Anodontia Vera), is a rare genetic disorder characterized by the congenital absence of all primary or permanent teeth. It is associated with skin and nerve syndromes called the ectodermal dysplasias. Anodontia is usually part of a syndrome and seldom occurs as an isolated entity.

Anodontia is the congenital absence of teeth (most known as missing laterals) and can occur in some or all teeth (partial anodontia or hipodontia), it may involve both the primary (baby Teeth) and the permanent teeth. 

Dental Anomalies can range from missing or stained teeth to cleft palates.The National Institute of Dental and Craniofacial Research (NIDCR) estimates that in the United States a baby is born every hour with a craniofacial defect.

 Antagonist is a term used in dentistry: (the opposing tooth is an antagonist) 

Anterior Teeth:

1. Incisors:

Four uppers and four lowers. There are central incisors and lateral incisors. These function in cutting food, articulating speech, appearance, and for support of the lips.

2. Canines:

Two upper and two lower. In humans, they function along with the incisors for support of the lips, cutting or shearing of food, and as guideposts in occlusion. In traditional restorative dentistry, they are the cornerstones of the dental arch.

An Antimicrobial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes (microbicidal) or prevent the growth of microbes (microbistatic).

Antiseptic are antimicrobial substances which are applied to living tissues/skin to decrease the likeliness of infection, sepsis or putrefaction. They should generally be differentiated from antibiotics which tear down micro-organisms inside the body and from disinfectants, which obliterate micro-organisms placed on non-living objects.

Generally quiet a few antiseptics are true germicides, proficient of tearing down microbes, where as others are simply bacteriostatic which generally stops or slows down their growth. Antibacterials are basically antiseptics which only take action against bacteria.

Anug more commonly known as trench mouth a disorder being among soldiers during World War 1 or Vincents Disease after the French physician Henri Vincent (1862-1950)

Anug also has many other names including: Acute Membranous Gingivitis, Fusospirillary Gingivitis, Fusospirillosis Gingivitis, Necrotizing Gingivitis, Phagedenic Gingivitis, Ulcerative Gingivitis or Vincent Gingivitis.

Anug is often brought by stress and / or smoking and is a painful infection with ulceration swelling and sloughing off of dead tissue from the mouth and throat due to the spread of the infection from the gums. Other causes for the disease may include poor oral hygiene, poor nutrition, tooth and mouth infection. Anug is a rare condition which typically may effect people ages between 15 and 35.

The healthy mouth usually contains a balance of different microorganisms. Anug occurs when there is an overabundance of abnormal mouth bacteria resulting in infection of the gums. Viruses can also be involved in allowing the bacteria to overgrow. These bacteria release poisons which irritate the gums causing further infection. If untreated you will eventually lose your teeth.

Good oral hygiene is therefore important to prevent trench mouth (Anug) that includes brushing and flossing on a regular daily basis in conjunction with regular professional cleaning and examination. Good nutrition and good general health also prevent the disorder. Other measure to prevent trench mouth include stop smoking and to learn how to deal with stress.

The symptoms of anug are easy to spot this includes gum bleeding in response to any pressure or irritation reddened gums, a grayish film on the gums, crater like ulcers in conjunction with foul taste in the mouth and bad breath. Professional cleaning of the gums is necessary as well as irrigation of the mouth with salt water or peroxide solution which may help to relieve symtoms.

Apical: toward the apex, the tip of the root.

Canker Sores are usually found on the movable parts of the mouth, such as the tongue or the inside lining of the lips and cheeks, and at the base of the gums. The ulcers begin as small oval or round reddish swellings that usually burst within a day. The ruptured sores are covered by a thin white or yellow membrane and edged by a red halo. Generally, the sores heal within two weeks without scarring. Fever is rare, and the sores are rarely associated with other diseases. Usually, a person has only one or a few canker sores at a time.

The Arch is the shape assumed collectively by upper and lower teeth. The dental arches, the individual row of teeth forming a tooth row attached to their respective jaw bones have a distinctive shape known as a catenary arch.

 Articulating Paper is used to mark the contacts on the occluding surface (the top of the teeth). This is very important when receiving a crown. All teeth need to have equal contact with the opposing teeth .

An Articulator is a "dental device" that works as close as practical to the way the mouth works. Dental Models taken with impressions and poured in dental stone are placed on the articulator either for examination and diagnosis, or to construct dental appliances. Special records are taken (bite) to accurately position the dental models on the articulator. The facebow record is a measurement from the upper teeth to the joints. The centric relation or bite record is a measurement of where the teeth are positioned with the joints positioned correctly before the teeth actually come into contact.

Aspirator's are used to help the patient remove the saliva in order to prevent swallowing while a dental procedure is done.

 Ideally, the incisal edges of the teeth should follow the contour of the lips.  

Attachment Level:

The distance in millimeters that exists between the edge of the enamel of a tooth to the gum tissue that is adherent to its root. This attached tissue is at the bottom of a sulcus or a pocket of any given tooth. (Distance in millimeters from the cemento-enamel junction to the junctional epithelium). (Epithelial Attachment)

Attrition is the loss of teeth structure by the mechanical forces from opposing teeth.

Attrition initially affects the enamel and, if unchecked, may proceed to the underlying dentin. Once past the enamel attrition quickly destroys the much softer dentin.

The most common cause of attrition is bruxism. Parafunctional habits such as chewing and clicking the teeth together nervously, place a greater amounts of forces on opposing teeth and begin to wear the teeth down. Wear usually begins on the incisal (front teeth) or occlusal surface (molar teeth).

Functional habits are those as chewing and swallowing which usually puts very little force on the opposing teeth.

Characteristic Features: Development of a facet (flat surface with circumscribed and a well defined border). Opposing tooth faced will match perfectly in occlusion.

The Axon is the elongated fiber that extends from the cell body to the terminal endings and transmits the neural signal. The larger the Axon, the faster it transmits information.