Transcript Dentifrices According to the dictionary, the term

Pit-and-Fissure Sealants -
how sealants can provide a primary preventive means of reducing the need for
operative treatment as 77% of the children 12 to 17 years old in the United States
have dental caries in their permanent teeth.1
Introduction
Fluorides are highly effective in reducing the number
of carious lesions occurring on the smooth surfaces of enamel and
cementum. Unfortunately, fluorides are not equally effective in
protecting the occlusal pits and fissures, where the majority of
carious lesions occur. Considering the fact that the occlusal
surfaces constitute only 12% of the total number of tooth surfaces,
it means that the pits and fissures are approximately eight times as
vulnerable as the smooth surfaces. The placement of sealants is a
highly effective means of preventing these diseses.
A sealant is probably indicated if:
• The fossa selected for sealant placement is well isolated from
another fossa with a restoration.
• The area selected is confined to a fully erupted fossa, even
though the distal fossa is impossible to seal due to inadequate
eruption.
• An intact occlusal surface is present where the contralateral tooth
surface is carious or restored; this is because teeth on opposite sides of
the mouth are usually equally prone to caries.
• An incipient lesion exists in the pit-and-fissure.
• Sealant material can be flowed over a conservative class I composite or
amalgam to improve the marginal integrity, and into the remaining pits
and fissures to achieve a de facto extension for prevention.
Other Considerations in Tooth Selection
All teeth meeting the previous criteria should be sealed and resealed
as needed. Where the cost-benefit is critical and priorities must be established,
such as occurs in many public health programs,
ages 3 and 4 years are the most important times for sealing the eligible
deciduous teeth;
.
ages 6 to 7 years for the first permanent molars;
and ages 11 to 13 years for the second permanent molars
and premolars. Currently, 77% of the children 12-to-17years-old in the United States have dental caries in their
permanent teeth.
Many school days would be saved, and better dental
health would be achieved in School Dental Health Clinic
programs by combining sealant placement and rregular
fluoride exposure
Background of Sealants
Buonocore first described the fundamental principles of placing sealants
in the late 1960s.He describes a method to bond poly-methylmethacrylate
(PMMA) to human enamel conditioned with phosphoric acid. Practical use of
this concept however, was not realized until the development of bisphenol Aglycidyl methacrylate (Bis-GMA), urethane dimethacrylates (UDMA) and
trithylene glycol dimethacrylates (TEGDMA) resins that possess better
physical properties than PMMA. The first successful use of resin sealants was
reported by Buonocore in the 1960s.
VIDEO
The Saliva Compartment
The saliva is derived mainly from the major salivary glands the parotid, submandibular, and
sublingual glands. Of these, the parotid elaborates a serous (watery, mucous-poor) fluid
containing electrolytes, but is relatively low in organic substances.
.
The parotid gland secretes the majority of the sodium bicarbonate that is essential in
neutralizing acids produced by cariogenic bacteria in the dental plaque, and the
majority of the enzyme amylase that initiates intraoral digestion of carbohydrates.
The submandibular gland secretes a mixed serous and mucous fluid, while the
sublingual gland has a greater proportion of mucous output than the other major
glands.
The minor glands palatal, lingual, buccal, and labial salivary glands empty onto the
mucus membrane in many locations on the palate, under the tongue, and on the
inner side of the cheeks and lips. These minor glands are mainly mucous secreting
glands that lubricate these surfaces and allows for improved mastication and
passage of food substance into the esophagus. The minor salivary glands also
contribute fluoride that bathes the teeth and enhances caries resistance.
Pure saliva produced by the oral glands is sterile, until it is
discharged into the mouth. When the fluids from all major and
minor glands mix with each other, this secretion becomes known
as whole saliva. Whole saliva is further altered by the presence of
particles of food, tissue fluid, lysed bacteria, and sloughed
epithelial cells. It becomes even more complex with the inclusions
of living cells and their metabolic products, for example, bacteria
and leucocytes, the latter derived from the gingival crevices and
tonsils
Functions of saliva
The physical and chemical protective functions of saliva can be divided into five
convenient categories
(1)-lubrication,
(2) flushing/rinsing,
(3) chemical,
(4) antimicrobial (includes antibacterial, antifungal and antiviral), and
(5) maintenance of supersaturation of calcium and phosphate level bathing the
enamel, helping to stymie demineralization and/or to aid remineralization of tooth
structure. To reinforce the concept expressed in Peretz aptly opined that saliva can
be considered similar to enamel but in a liquid phase.
Lubrication and Flushing
A very thin microscopic layer of mucus protects the oral hard and soft tissues from
the often harsh and abrasive foods, as they are being chewed and swallowed. It
also protects the soft tissues from dessication and the teeth from abrasion. The
moistening of food by saliva facilitates chewing and swallowing. Speech is
enhanced by the reduced friction between the dry tongue and soft tissues.
Coversely, a lack of saliva (xerostomia) results in a greatly increased risk of caries
with its accompaniment of an extremely annoying dry-mouth sensation. Chewing,
swallowing and speaking can all be difficult and uncomfortable with dry-mouth
syndrome and often requires frequent ameliorating sips of water.
Flow Rate
Providing a constant fluid flow is probably the most important defense function of the
salivary glands, because it is the fluid that transports the buffering agents, the
antimicrobials, and the mineral content of saliva to help control the equilibrium between
the demineralization and remineralization of tooth structure. Also, the fluid output of the
glands is essential for diluting acids, flushing food particles embedded around the teeth,
clearing refined carbohydrates (acid-producing sugar substrates) and physically removing
any displaced bacteria Oral fluids in contact with food particles results in solubilizing food
substances that interact with the taste buds to provide an accurate assessment of taste.2