Maintaining a Healthy Smile and Different Treatments
Maintaining a Healthy Smile and Different Treatments:
is the delivery of fluoride to the teeth topically or systemically in order to
prevent tooth decay (dental caries) which results in cavities. Most commonly,
fluoride is applied topically to the teeth using gels, varnishes, toothpaste/dentifrices
or mouth rinse. Systemic delivery involves fluoride supplementation using
water, salt, tablets or drops which are swallowed. Tablets or drops are rarely
used where public water supplies are fluoridated.
Oral hygiene is the practice of
keeping the mouth and teeth clean to prevent dental problems, most commonly, dental
cavities, gingivitis, and bad breath. There are also oral pathologic conditions
in which good oral hygiene is required for healing and regeneration of the oral
tissues. These conditions included gingivitis, periodontitis, and dental trauma,
such as subluxation, oral cysts, and following wisdom tooth extraction.
Cleaning of teeth
is the removal of dental plaque and tartar from teeth to prevent cavities,
gingivitis, and gum disease. Severe gum disease causes at least one-third of
adult tooth loss.
Tooth decay is
the most common global disease. Over 80% of cavities occur inside pits and
fissures on chewing surfaces where brushing cannot reach food left trapped
after every meal or snack, and saliva or fluoride have no access to neutralise
acid and remineralise demineralised teeth, unlike easy-to-reach surfaces, where
fewer cavities occur.
which are applied by dentists, cover and protect fissures and grooves in the
chewing surfaces of back teeth, preventing food from becoming trapped thus
halting the decaying process. An elastomer strip has been shown to force
sealant deeper inside opposing chewing surfaces and can also force fluoride toothpaste
inside chewing surfaces to aid in remineralising, demineralised teeth.
recorded history, a variety of oral hygiene measures have been used for teeth
cleaning. This has been verified by various excavations done throughout the
world, in which chew sticks, tree twigs, bird feathers, animal bones and porcupine
quills were recovered. Many people used different forms of teeth cleaning
tools. Indian medicine (Ayurveda) has used the neem tree, or daatun, and
its products to create teeth cleaning twigs and similar products; a person
chews one end of the neem twig until it somewhat resembles the bristles of a toothbrush,
and then uses it to brush the teeth. In the Muslim world, the miswak, or siwak,
made from a twig or root, has antiseptic properties and has been widely used
since the Islamic Golden Age. Rubbing baking soda or chalk against the teeth
was also common.
dentists recommend that teeth be cleaned professionally at least twice per
year. Professional cleaning includes tooth scaling, tooth polishing,
and, if tartar has accumulated, debridement; this is usually followed by a
fluoride treatment. However, the American Dental Hygienists' Association (ADHA)
publicly stated in 1998 that there is an absence of evidence that scaling and
polishing provides therapeutic value. The Cochrane Oral Health Group reviewed
nine studies but found them to be of insufficient quality and not enough
evidence to support the claims of the benefits of regular tooth scaling or
cleanings by a dental hygienist, good oral hygiene is essential for preventing
tartar build-up which causes the problems mentioned above. This is done through
careful, frequent brushing with a toothbrush, combined with the use of dental
floss to prevent accumulation of plaque on the teeth.
Plaque is a
yellow sticky film that forms on the teeth and gums and can be seen at gum
margins of teeth with a food dye. The bacteria in plaque convert carbohydrates
in food (such as sugar) into acid that demineralises teeth, eventually causing
cavities. Daily brushing and flossing removes plaque and can prevent tartar
from forming on the teeth.
Plaque can also
cause gum irritation (gingivitis), making them red, tender and cause them to
bleed. In some cases, the gums pull away from the teeth (receding gums),
leaving cavities inhabited by bacteria and pus. If this is not treated, bones
around the teeth can be destroyed. Teeth may become loose or have to
be removed due to periodontal (gum) disease, mostly in adults. Eating a
balanced diet and limiting snacks can prevent tooth decay and periodontal
diseases. The Fédération dentaire internationale (FDI World Dental
Federation) has promoted foods such as raw vegetables, plain yogurt, cheese, or
fruit as dentally beneficial—this has been echoed by the American Dental
The use of dental
floss is an important element of oral hygiene, since it removes plaque and
decaying food remaining stuck between the teeth. This food decay and plaque
cause irritation to the gums, allowing the gum tissue to bleed more easily.
Acidic foods left on the teeth can also demineralise teeth, eventually causing
Flossing for a
proper inter-dental cleaning is recommended at least once per day, preferably
before brushing so fluoride toothpaste has better access between teeth to help
remineralise teeth, prevent receding gums, gum disease, and cavities on
the surfaces between the teeth.
recommended to use enough floss to enable easy use, usually ten or more inches
with three to four inches of taut floss to put between teeth. Floss is then
wrapped around the middle finger and/or index finger, and supported with the thumb
on each hand. It is then held tightly to make taut, and then gently moved up
and down between each tooth. It is important to floss under visible areas by
curving the floss around each tooth instead of moving up and down on gums,
which are much more sensitive than teeth. However, bleeding gums are normal
upon first usage of floss, and will harden with use. One should use an unused
section of the floss when moving around different teeth. Removing floss from
between teeth requires using the same back-and-forth motion as flossing, but
gently bringing the floss up and out of gaps between teeth.
brush, also called an interproximal brush or a proxy brush, is a small brush,
typically disposable, either supplied with a reusable angled plastic handle or
an integral handle, used for cleaning between teeth and between the wire of
dental braces and the teeth. Brushes are available in a range of widths, color
coded as per ISO 16409. Interdental brushes are classified according to ISO
standard 16409:2006. The ISO brush sizes range from 1 to 7. The ISO brush size
is determined by the PHD or Passage Hole Diameter in mm. This PHD is the
minimum diameter of a hole that the interdental brush will pass through without
deforming the brush wire stem. A peer-reviewed clinical study has found that
using a toothbrush and an interdental brush more effectively removes plaque
than using a toothbrush and dental floss.
tongue as part of daily oral hygiene is essential, since it removes the
white/yellow bad-breath-generating coating of bacteria, decaying food
particles, fungi (such as Candida), and dead cells from the dorsal area
of the tongue. Tongue cleaning also removes some of the bacteria species which
generate tooth decay and gum problems.
Massaging the gums
with toothbrush bristles is generally recommended for good oral health.
professionals recommend oral irrigation as a way to clean teeth and gums.
reach 3–4 mm under the gum line. Oral irrigators use a pressured, directed
stream of water to disrupt plaque and bacteria.
The main advantage of a direct dental composite
over traditional materials such as amalgam is improved aesthetics.
Composites can be made in a wide range of tooth colors allowing near invisible
restoration of teeth. Composites are glued into teeth and this strengthens the
tooth's structure. The discovery of acid etching (producing enamel
irregularities ranging from 5-30 micrometers in depth) of teeth to allow a
micromechanical bond to the tooth allows good adhesion of the restoration to
the tooth. This means that unlike silver filling there is no need for the
dentist to create retentive features destroying healthy tooth. The acid-etch
adhesion prevents micro leakage; however, all white fillings will eventually
leak slightly. Very high bond strengths to tooth structure, both enamel and dentin,
can be achieved with the current generation of dentin bonding agents.
Clinical survival of composite restorations placed
in posterior teeth has been shown to be significantly lower than amalgam
restorations. However, improvements in
composite technology and techniques have improved their longevity.
Direct dental composites
A hand-held wand that emits primary blue light (λmax=450-470nm) is used
to cure the resin within a dental patient's mouth.
Direct dental composites are placed by the dentist
in a clinical setting. Polymerization is accomplished typically with a hand
held curing light that emits specific wavelengths keyed to the initiator
and catalyst packages involved. When using a curing light, the light
should be held as close to the resin surface as possible, a shield should be
placed between the light tip and the operator's eyes, and that curing time
should be increased for darker resin shades. Light cured resins provide denser
restorations than self-cured resins because no mixing is required that might
introduce air bubble porosity.
Direct dental composites can be used for:
- Filling cavity preparations
- Filling gaps (diastemas) between teeth using a shell-like
- Minor reshaping of teeth
- Partial crowns on single teeth
also known as tooth whitening, is a common procedure in general
dentistry but most especially in the field of cosmetic dentistry. According to
the FDA, whitening restores natural tooth color and bleaching
whitens beyond the natural color. There are many methods available, such as brushing,
bleaching strips, bleaching pen, bleaching gel, laser bleaching, and natural
methods use carbamide peroxide which reacts with water to form hydrogen
peroxide. Carbamide peroxide has about a third of the strength of hydrogen
peroxide. This means that a 15% solution of carbamide peroxide is the rough
equivalent of a 5% solution of hydrogen peroxide. The peroxide oxidizing agent
penetrates the porosities in the rod-like crystal structure of enamel and
bleaches stain deposits in the dentin. Power bleaching uses light energy to
accelerate the process of bleaching in a dental office.
is not a modern invention. Ancient Romans, for example, utilized urine and goat
milk as a product to make and keep their teeth whiter.
Orthodontics, formerly orthodontia
(from Greek orthos "straight or proper or perfect"; and odous
"tooth") is the first specialty of dentistry that is concerned with
the study and treatment of malocclusions (improper bites), which may be a
result of tooth irregularity, disproportionate jaw relationships, or both.
Orthodontic treatment can focus on dental displacement only, or can deal with
the control and modification of facial growth. In the latter case it is better
defined as "dentofacial orthopaedics". Orthodontic treatment can be
carried out for purely aesthetic reasons with regards to improving the general
appearance of patients' teeth. However, there are orthodontists who work on
reconstructing the entire face rather than focusing exclusively on teeth.
Veneers are an important tool for the cosmetic
dentist. A dentist may use one veneer to restore a single tooth that may have
been fractured or discolored, or multiple teeth to create a "Hollywood"
type of smile makeover. Many people have small teeth resulting in spaces
that may not be easily closed by orthodontics. Some people have worn away the
edges of their teeth resulting in a prematurely aged appearance, while others
may have malpositioned teeth that appear crooked. Multiple veneers can close
these spaces, lengthen teeth that have been shortened by wear, fill the black
triangles between teeth caused by gum recession, provide a uniform color,
shape, and symmetry, and make the teeth appear straight. Dentists also
recommend using thin porcelain veneers to strengthen worn teeth. Thin veneers
is an effective option for aging patients with worn dentition. In many cases,
minimal to none tooth preparation is needed when using porcelain veneers.
The problem of overuse of porcelain veneers by certain
cosmetic dentists in 'Confessions of a Former Cosmetic Dentist'. He suggests
that the use of veneers for 'instant orthodontics' or simulated straightening
of the teeth is harmful, especially for younger people with healthy teeth.
Leading dentists caution that minor cosmetic or wear is not justification for
porcelain or ceramic veneers, the tooth preparation of which may destroy 3-30%
of the tooth surface during tooth preparation for veneers, and after 10 years,
50% of veneers are gone, need retreatment, or no longer in satisfactory
Inlays, onlays, porcelain
veneers, crownlays and all varieties of crowns can also be
fabricated out of ceramic materials, such as in CAD/CAM Dentistry or
traditionally in a dental laboratory setting. CAD/CAM technology can allow for
the immediate, same day delivery of these types restorations which are milled
out of blocks of solid porcelain which matches the shade or color of the
patients teeth. Traditionally, all-ceramic restorations have been made off site
in a dental laboratory either out of feldspathic porcelains or pressed
ceramics. This indirect method of fabrication involves molds and
temporaries, but can yield quite beautiful end-results if communication between
the laboratory and the dentist is sound. The greatest difference between these
two differing modalities lies in the fact that the CAD/CAM route does not
require temporization, while the laboratory-fabricated route does. Some argue
that this lack of temporization can result in a decreased need for root canal
therapy, as there is no temporary leakage between visits.
Restorations that are all-ceramic require wide
shoulder margins and reductions of at least 1.0 - 1.5 mm across the occlusal
(chewing) surfaces of the teeth. There are times where this reduction would be
considered excessive, just as there are times when previous restorations or
pathology require this much removal or more. Arguments against using
all-ceramic restorations include a greater chance of fracture, when little to
no enamel remains for proper adhesive bonding, or potentially when the patient clenches
or grinds their teeth ("bruxes") excessively. Indications for
using all-ceramic restorations include more aesthetic results, when metal
compatibility issues exist, and when removal of less tooth structure is
desired. All-ceramic restorations do not require resistance and retention form
and consequently less surface area need be removed and the restoration will
still stay in place by virtue of micromechanical and chemical bonding.
Ceramic materials such as lithium disilicate dental
ceramics have recently been developed which provide greater strength and
life-expectancy of dental restorations.
Although no dental restoration lasts forever, the
average lifespan of a crown is around 10 years. While this is considered
comparatively favorable to direct restorations, they can actually last
up to the life of the patient (50 years or more) with proper care. One reason
why a 10 year mark is given is because a dentist can usually provide patients
with this number and be confident that a crown that the dental lab makes will
last at least this long. It should be noted that many dental insurance plans in
North America will allow for a crown to be replaced after only five years.
The most important factor affecting the lifespan of
any restorative is the continuing oral hygiene performed by the patient.
Other factors depend on the skill of the dentist and their lab technician, the
material used and appropriate treatment planning and case selection.
Full gold crowns last the longest, as they are
fabricated as a single piece of gold. PFMs, or porcelain-fused-to-metal crowns
possess an additional dimension in which they are prone to failure, as they
incorporate brittle porcelain into their structure. Although incredibly strong
in compression, porcelain is terribly fragile in tension, and
fracture of the porcelain increases the risk of failure, which rises as the
amount of surfaces covered with porcelain is increased. A traditional PFM with
occlusal porcelain (i.e. porcelain applied to the biting surface of a posterior
tooth) has a 7% higher chance of failure per year than a corresponding full
When crowns are used to restore endodontically
treated teeth, they decrease the potential of the tooth fracturing due to
the brittle devitalized nature of the tooth and provide a better seal against
invading bacteria. Although the inert filling material within the root canal
blocks against microbial invasion of the internal tooth structure, it is
actually a superior coronal seal, or marginal adaptation of the restoration in
or on the crown of the tooth, which prevents reinvasion of the root canal.
Advantages and disadvantages
The main disadvantages of restoration with a crown
are extensive irreversible tooth preparation (grinding away) and higher costs
than for direct restorations such as amalgam or dental composite. The benefits,
as described above, include long-term durability and evidence-based success as
compared to other restorations or no treatment.
The crowning of two fairly large molars to sling a
bridge between them for a missing tooth is a costly and sometimes oversold
procedure. The increased food and bacteria trapping of the underside of the
bridge often offsets the benefits of the bridge element in maintaining the
positions of the opposing teeth and the loss of the ease of use and mouth feel
of two big natural teethIt is usually the damage to a tooth that dictates the
need for a crown, and alternative treatments are usually less effective. Risks and benefits can be weighed based on the
priorities of the patient.
An example of this occurs when a patient would like
to restore an edentulous area between healthy adjacent teeth. Before implants,
there were three options:
· Fixed partial denture (bridge)
· Removable partial denture
· No treatment
Those who could afford it were usually told by their dentists that a
bridge was their best choice, because it is much sturdier than removable
dentures and requires less looking after. When implants became available,
however, they were recommended as the best possible treatment, because the
virgin teeth adjacent to the edentulous area no longer needed to be cut in
order to fit the bridge. The affluent are thus told that a fixed partial
denture is no longer desirable, now that implants are available. However,
implants are significantly more expensive than a bridge, and the results are
generally much less immediate.
Types and materials
Comparison between a porcelain-metal dental crown, an all-porcelain
dental crown and a porcelain veneer laminate
There are many different methods of crown
fabrication, each using a different material. Some methods are quite similar,
and utilize either very similar or identical materials.
Full gold crown
Full gold crowns (FGCs) consist entirely of a
single piece of alloy. Although referred to as a gold crown, this
type of crown is actually composed of many different types of elements,
including but not limited to gold, platinum, palladium, silver,copper and tin. The first three elements listed are noble
metals, while the last three listed are base metals. Full gold
crowns are of better quality when they are high in noble content. According to
the American Dental Association, full gold crown alloys can only be
labeled as high noble when they contain at least 60% noble metal, of
which at least 40% must be gold.
The process of constructing a full gold crown
begins at the dentist's office. The clinician will begin by preparing
the tooth by removing enough tooth tissue to allow for the crown. Once the
preparation has been finalized the clinician will take an impression
which is basically a mold of the patient's mouth. The impression and patient
details are sent to a dental laboratory where the dental technician will flow
dental gypsum into the impression to make a dental model. This model is an
exact reproduction of the situation in the patient's mouth. The dental
technician now has the information required to model a wax pattern of the final
restoration allowing for the tooth shape, occlusion and preparation. The
wax pattern can be removed from the model and a wax sprue pattern is
attached. The pattern is now ready to use in the Lost-wax casting
technique. It is invested in a gypsum or phosphate-bonded investment material,
allowed to set then put into a furnace where the wax is completely burnt out
leaving a hole for the gold to be poured in. Once the crown has cooled, the
technician can remove the sprue, fit and polish the crown ready for
cementation. The crown is returned to the dentists office where they can remove
any temporary crown and cement the finished gold crown.
Porcelain-fused-to-metal dental crowns (PFMs) have
a metal shell on which is fused a veneer of porcelain in a high heat oven. The
metal provides strong compression and tensile strength, and the porcelain gives
the crown a white tooth-like appearance, suitable for front teeth restorations.
These crowns are often made with a partial veneer that covers only the aspects
of the crown that are visible. The remaining surfaces of the crown are bare
metal. A variety of metal alloys containing precious metals and base metals can
be used. The porcelain can be color matched to the adjacent teeth.
Restorations without Metal
Chairside CAD/CAM Dentistry
The CAD/CAM method of fabricating
all-ceramic restorations is by electronically capturing and storing a
photographic image of the prepared tooth and, using computer technology,
crafting a 3D restoration design that conforms to all the necessary
specifications of the proposed inlay, onlay or single-unit crown;
there is no impression. After selecting the proper features and making various
decisions on the computerized model, the dentist directs the computer to send
the information to a local milling machine. This machine will then use
its specially designed diamond burs to mill the restoration from a solid ingot
of a ceramic of pre-determined shade to match the patient's tooth. After about
20 minutes, the restoration is complete, and the dentist sections it from the
remainder of the unmilled ingot and tries it in the mouth. If the restoration
fits well, the dentist can cement the restoration immediately. A dental CAD/CAM
machine costs roughly $100,000, with continued purchase of ceramic ingots and
Typically, over 95% of the restorations made using
Dental CAD/CAM and Vita Mark I and Mark II blocks are still clinically
successful after 5 years. Further, at least 90% of restorations still function
successfully after 10 years. Advantages of the Mark II blocks over ceramic
blocks include: they wear down as fast as natural teeth, their failure loads
are very similar to those of natural teeth, and the wear pattern of Mark II
against enamel is similar to that of enamel against enamel.
Popularly known as the "Empress Crown,"
the leucite reinforced system is superficially similar to a gold crown
technique in that a hollow investment pattern is made, but the similarities
stop there. A specially designed pressure-injected leucite-reinforced
ceramic is then pressed into the mold by using a pressable-porcelain-oven, as though
the final all-ceramic restoration has been "cast." The crown that is
constructed can be stained and glazed or cut-back and layered with feldspathic
ceramic to match the patients natural color and shape.
A study by the Umeå University in Sweden,
led by Göran Sjögren, sought to study the effectiveness of leucite-reinforced
crowns. Titled “Clinical examination of leucite-reinforced glass ceramic
crowns (Empress) in general practice: a restrospective study”, it found
Empress crowns cracked at approximately only a 6% rate, with the integrity of
86% of the remaining samples being called "excellent."
Alumina was introduced as a dental material in 1989
where the material was slip cast and infused with glass. More recently
alumina core have been constructed with a CAD/CAM dentistry technique
where a oversized core is milled from a pre-sintered block of Al2O3.
The block is sintered and shrinks to the correct size. This alumina core can be
layered with feldspathic ceramics to make a true to life color and shape.
Zirconia is a very
hard ceramic that is used as a strong base material in some full ceramic
restorations. The zirconia used in dentistry is zirconium oxide which
has been stabilized with the addition of yttrium oxide. The full name of
zirconia used in dentistry is yttria-stabilized zirconia or YSZ.
The zirconia substructure of a crown is usually
designed on a digital representation of the patients mouth, which is captured
with a 3d digital scan of the patient, impression or model. The substructure is
then milled from a block of zirconia in a soft pre-sintered state. Once milled
the pre-sintered zirconia is sintered in a furnace, where it shrinks by
20% and reaches it full strength of approximately 850MPa.
On the core structure a dental technician can layer
an aesthetic ceramic to create the final colour and shape of the tooth. Sometimes
a 'monolithic' crown can be made exclusively of the zirconia ceramic with no
aesthetic ceramic layered on top. These crowns tend to be dense in appearance
with a high value and lack translucency and fluorescence.
Dentures, also known as false
teeth, are prosthetic devices constructed to replace missing teeth, and
which are supported by surrounding soft and hard tissues of the oral cavity.
Conventional dentures are removable, however there are many different denture
designs, some which rely on bonding or clasping onto teeth or dental implants.
There are two main categories of dentures, depending on whether they are used
to replace missing teeth on the mandibular arch or the maxillary arch.
What is the most significant advantage
to the mini-implant?
A: The most significant advantage of the mini-implant is
that it is a simple procedure for the doctor and patient, it is cost effective
and requires no flap or suturing in most cases. Furthermore, the mini-implant
can be restored with a permanent crown or bridge restoration.
Q : Could you describe the configuration of the IMTEC
A : The mini-implants are 1.8 or 2.3mm in diameter and
come in 10, 13, 15 and 18mm lengths. The 13mm and 15mm are the most commonly
used. There are two styles of implant configuration. The classic mini-implant
had a ball head, square polished neck and threads right up to the neck. The
newer version has a polished collar instead of threads just below the neck.
Q : What is the orientation of the correctly inserted
A : The square neck should be set about 3-4mm above the
Q : What are the indications for selecting the
A : We have used the mini-implants to support single
crowns, fixed partial dentures and overdentures. There are few contraindications
for selecting a mini-implant. For example if you are placing an implant
immediately after an extraction, the mini-implant may be too narrow for
predictable healing. You might select a wider conventional implant for that
kind of a situation.
Q : Do you feel that most general dentists could be
comfortable placing and restoring the mini-implants?
A: Absolutely. A general dentist can place
mini-implants. As long as you have the proper training and background, you
should be able to place and restore these.
Q : Do you have a formula or system for deciding how many
mini-implants dental (MDI) to place. For example, in a square maxillary arch
how many MDI’s would you place to replace #7-8-9-10?
A : In general we use 1 MDI per anterior tooth and 2
MDI’s for each molar. For example for replacing #7-10 we would use four MDIs.
For replacing A maxillary canine we would use an 2.3mm MDI with a max thread.
Q : What is the proper or ideal alignment of the
mini-implant? Long axis of the tooth replaced? What would be the alignment
planned for an MDI to replace #8? Through long axis of the cingulum of the
A : We place an MDI to replace a maxillary central
incisor on the available bone bissecting the buccal and lingual plates.
Occasionally we use a custom abutment to angle the implant lingually.
Q : What kind of abutment interface do you have for
cementing a crown or fixed partial denture. The most commonly displayed MDI has
a ball at the coronal end and a square neck directly subjacent.
A : We cement the crown directly to the ball and square
on the implant. The crown is like a pontic with a cylindrical hole under it. We
use a resin
Q : For a maxillary overdenture do you use MDIs to
support a bar or would you use free-standing. How many for each.
A : We generally do not use a bar but prefer free
standing MDI’s. We use 6-8 MDI’s with the o-balls to support a maxillary
complete overdenture with o-rings.