scaling (removal of calculi) and advise
on oral hygiene methods.
dentition The arrangement, number, and
type of teeth in the mouth. In young
children, primary dentition comprises
20 teeth (incisors, canines, and molars).
These teeth are replaced between the
ages of 7 and 13 years by secondary (per-
manent) dentition. Secondary dentition
comprises 32 teeth (incisors, canines,
premolars, and molars). The third molars
(wisdom teeth) may not erupt until 18–21
years of age. (See also eruption of teeth.)probe for dental cavities, chipped teeth,
or fillings. Dental X-raysare sometimes
carried out to check for problems that
may not be visible. Dentists also check
how well the upper and lower teeth
come together. Regularexaminations in
children enable the monitoring of the
replacement of primary teeth by perma-
nent, or secondary, teeth. Referral for
orthodontictreatment may be made.
dental extractionSee tooth extraction.
dental X-rayAn image of the teeth
and jaws that provides information for
detecting, diagnosing, and treating con-
ditions that can threaten oral and
general health. There are 3 types of den-
tal X-ray:periapical X-ray, bite-wing
X-ray, and panoramic X-ray.
Periapical X-rays are taken using X-ray
film held behind the teeth. They give
detailed images of whole teeth and the
surrounding tissues. They show unerupt-
ed or impacted teeth, root fractures,
abscesses, cysts, and tumours, and can
help diagnose some skeletal diseases.
Bite-wing X-rays show the crowns of the
teeth and can detect areas of decay and
changes in bone due to periodontal dis-
ease. Panoramic X-rays show all the
teeth and surrounding structures on one
large film. They can show unerupted or
impacted teeth, cysts, jaw fractures, or
tumours. The amount of radiation re-
ceived from dental X-rays is extremely
small. However, dental X-rays should be
avoided during pregnancy.
dentifriceA paste, powder, or gel used
with a toothbrush to clean the teeth. It
contains a mild abrasive, detergents,
binding and moistening agents, thick-
ening agents, colourings, flavourings,
and usually fluoride.
dentineHard tissue surrounding the
pulp of a tooth (see teeth).
dentistryThe science or profession
concerned with the teeth and their sup-
porting structures. Most dentists work
in general dental practice; others prac-
tise in a specialized branch of dentistry.
Dentists in general practice undertake
all aspects of dental care. They may refer
patients to a consultant in one of the
specialized branches of dentistry, such as
orthodontics, prosthetics, endodontics, and
periodontics. Dental hygienists carry out
DENTAL EXTRACTION DENTITION
D
Central
incisorCentral
incisorLateral
incisorLateral
incisorSecond
premolarUPPER
TEETHUPPER
TEETHLOWER
TEETHLOWER
TEETHFirst
molarFirst
molarSecond
molarSecond
molarFirst
premolarThird
molarDENTITIONCanineCaninePRIMARY TEETHSECONDARY TEETH