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Dental Questions and Answers




The opinions  within this web page are not ours and replies relate to the period
when questions were asked. Authors have been credited  for the answers given.
This information is provided is not intended to replace the medical
advice of your doctor or health care provider. Please consult your dentists
for advice about a specific medical condition


Stop Periodontitis Fast
1. What new methods are under development to treat and prevent tooth decay?
2. What are dental sealants, who should get them, and how long do they last?
3. When will drill-less dentistry become a reality?
4. What’s the latest word on the safety of amalgam-type fillings?
1. Is Chloroform Permissible?
2. Cross compatibility of Resin Composites and Dentin Bonding Agents
3. Minimizing Bubbles in Investments and Stone
4. Captek Alloy System
5. The Frustrations of Making Provisionals
6. Dentin bonding products
7. Information on obtura II and system B
8. Just seal it
9. Information on Thermafil plus system
10. Best solution to save the extracted tooth

What new methods are under development to treat and prevent tooth decay?
Several new treatments are under development. One experimental technique uses fluorescent light to detect
the development of cavities long before they can be detected by traditional means, such as X-rays or dental
examination. In many cases, if cavities can be detected early, the decay process can be stopped or reversed.
Researchers are also working on a "smart filling" to prevent further tooth decay by slowly releasing fluoride
over time around fillings and in adjacent teeth.

New means to prevent tooth decay are also being studied. A study has shown that a chewing gum that contains
the sweetener xylitol temporarily retarded the growth of bacteria that cause tooth decay. In addition, several
materials that slowly release fluoride over time, which will help prevent further decay, are being explored.
These materials would be placed between teeth or in pits and fissures of teeth. Toothpastes and mouth rinses
that can reverse and "heal" early cavities are also being studied.

What are dental sealants, who should get them, and how long do they last?

Sealants are a thin, plastic coating that are painted on the chewing surfaces of teeth — usually the back teeth
(the premolars, and molars) — to prevent tooth decay. The painted on liquid sealant quickly bonds into the
depressions and groves of the teeth forming a protective shield over the enamel of each tooth.

Typically, children should get sealants on their permanent molars and premolars as soon as these teeth come in.
In this way, the dental sealants can protect the teeth through the cavity-prone years of ages 6 to 14. However,
adults without decay or fillings in their molars can also benefit from sealants.

Sealants can protect the teeth from decay for up to 10 years, but they need to be checked for chipping or wearing
at regular dental check-ups.

When will drill-less dentistry become a reality?
Drill-less dentistry, also called air abrasion and microabrasion, is being offered by some dentists now.
Air abrasion can be used to remove tooth decay, to remove some old composite restorations, to prepare a tooth
surface for bonding or sealants, and to remove superficial stains and discolorations. The air abrasion instrument
works like a mini sandblaster to spray away the decay or stain, or to prepare the tooth surface for bonding or
sealant application. With air abrasion, a fine stream of particles is aimed at the tooth surface. These particles
are made of silica, aluminum oxide, or a baking soda mixture and are propelled toward the tooth surface by compressed
air or a gas that runs through the dental handpiece. Small particles of decay, stain, etc, on the tooth surface
are removed as the stream of particles strikes them. The remnant particles are then "suctioned" away.

What’s the latest word on the safety of amalgam-type fillings?

Over the past several years, concerns have been raised about silver-colored fillings, otherwise called amalgams.
Because amalgams contain the toxic substance mercury, some people think that amalgams are responsible for causing
a number of diseases, including autism, Alzheimer’s disease, and multiple sclerosis.

The American Dental Association (ADA), the Food and Drug Administration (FDA), and numerous public health agencies
say amalgams are safe, and that any link between mercury-based fillings and disease is unfounded. The cause of autism,
Alzheimer’s disease, and multiple sclerosis remains unknown. Additionally, there is no solid, scientific evidence to
back up the claim that if a person has amalgam fillings removed, he or she will be cured of these or any other diseases.

As recently as March of 2002, the FDA reconfirmed the safety of amalgams. Although amalgams do contain mercury, when
they are mixed with other metals, such as silver, copper, tin, and zinc, they form a stable alloy that dentists have
used for more than 100 years to fill and preserve hundreds of millions of decayed teeth. The National Institutes of
Health has several large-scale studies currently under way to ultimately answer many of the questions raised about
silver-colored amalgams. Results of these studies are expected to be released in 2006.

In addition, there has been concern over the release of a small amount of mercury vapor from these fillings, but
according to the ADA, there is no scientific evidence that this small amount results in adverse health effects.

Is it possible to have an allergic reaction to amalgam?

It is possible, but fewer than 100 cases have ever been reported, according to the ADA. In these rare circumstances, mercury or one of the metals used in an amalgam restoration is thought to trigger the allergic response. Symptoms of amalgam allergy are similar to those experienced in a typical skin allergy, and include skin rashes and itching. Patients who suffer amalgam allergies typically have a medical or family history of allergies to metals. Once an allergy is confirmed, another restorative material can be used.

What role are lasers playing in the field of dentistry?
Lasers have been used in dentistry since 1995 to treat a number of dental problems. But, despite FDA approval, no laser system has received the American Dental Association’s Seal of Acceptance, which assures dentists that the product or device meets ADA standards of safety and efficacy, among other things. The ADA, however, states that it is cautiously optimistic about the role of laser technology in the field of dentistry.

Still, some dentists are using lasers to treat:

Tooth decay — Lasers are used to remove decay within a tooth and prepare the surrounding enamel for receipt of the filling. Lasers are also used to "cure" or harden a filling.
Gum disease — Lasers are used to reshape gums and remove bacteria during root canal procedures.
Biopsy or lesion removal — Lasers can be used to remove a small piece of tissue (called a biopsy) and send it for testing to determine if it is cancerous. It can also be used to remove lesions in the mouth and relieve the pain of canker sores.
Teeth whitening — Lasers are used to speed up the in-office teeth whitening procedures. A peroxide bleaching solution, applied to the tooth surface, is "activated" by laser energy, which speeds up of the whitening process.
How do whitening toothpastes work and how effective are they at whitening teeth?
All toothpastes help remove surface stains through the action of mild abrasives. Some whitening toothpastes contain gentle polishing or chemical agents that provide additional stain removal effectiveness. Whitening toothpastes can help remove surface stains only and do not contain bleach. Over-the-counter and professional whitening products contain hydrogen peroxide (a bleaching substance) that helps remove stains on the tooth surface, as well as stains deep in the tooth. None of the home use whitening toothpastes can come even close to producing the bleaching effect you get from your dentist’s office through chair side bleaching or power bleaching. Whitening toothpastes can lighten your tooth’s color by about one shade. In contrast, light-activated whitening conducted in your dentist’s office can make your teeth three to eight shades lighter.

What about whitening strips and whitening gels? What’s the opinion on these products?
Both of these products contain peroxide in a concentration that is much lower than the peroxide-based products that are used in your dentist’s office. Although some teeth lightening will be achieved, the degree of whitening is much lower than results achieved with in-office or dentist-supervised whitening systems. Additionally, use of over-the-counter products do not benefit from the close supervision of your dentist -- to determine what whitening process might be best for you, to check on the progress of the teeth whitening, and look for signs of gum irritation. On the positive, the over-the-counter gels and strips are considerably less expense (ranging from $10 to about $55) than the top-of-the line in-office whitening procedures, which can cost nearly $800.

Beyond simply changing the color of my teeth, I’m interested in changing the shape of my teeth. What options are available?
Several different options are available to change the shape of teeth, make teeth look longer, close spaces between teeth, or repair chipped or cracked teeth. Among the options are bonding, crowns, veneers, and re-contouring.

Dental bonding is a procedure in which a tooth-colored resin material (a durable plastic material) is applied to the tooth surface and hardened with a special light, which ultimately "bonds" the material to the tooth. A dental crown is a tooth-shaped "cap" that is placed over a tooth. The crowns, when cemented into place, fully encase the entire visible portion of a tooth that lies at and above the gum line. Veneers (also sometimes called porcelain veneers or dental porcelain laminates) are wafer-thin, custom-made shells of tooth-colored materials that are designed to cover the front surface of teeth. These shells are bonded to the front of the teeth. Recontouring or reshaping of the teeth (also called odontoplasty, enameloplasty, stripping, or slenderizing) is a procedure in which small amounts of tooth enamel are removed to change a tooth’s length, shape, or surface.

Each of these options differ with regard to cost, durability, "chair time" necessary to complete the procedure, stain resistant qualities, and best cosmetic approach to resolving a specific problem.

I have a terrible fear of going to the dentist yet I recognize the importance of seeing the dentist to maintain good oral health. What should I do?
If you fear going to the dentist, you are not alone. Between 9 percent and 15 percent of Americans state they avoid going to the dentist because of anxiety or fear. The first thing you should do is talk with your dentist. In fact, if your dentist doesn’t take your fear seriously, find another dentist. The key to coping with dental anxiety is to discuss your fears with your dentist. Once your dentist knows what your fears are, he or she will be better able to work with you to determine the best ways to make you less anxious and more comfortable.

The good news is that today there are a number of strategies that can be tailored to the individual to reduce fear, anxiety, and pain. These strategies include use of medicines (to either numb the treatment area or sedatives or anesthesia to help you relax), use of lasers instead of the traditional drill for removing decay, application of a variety of mind/body pain and anxiety-reducing techniques (such as guided imagery, biofeedback and deep breathing, acupuncture, mental health therapies), and perhaps even visits to a dentophobia clinic or a support group.

I’ve been a cigarette smoker for a number of years and am concerned about the possibility of developing oral cancer. What are the signs and symptoms of oral cancer?
First, it’s important to note that more than 25 percent of all oral cancers occur in people who do not smoke and who only drink alcohol occasionally. To answer your question, the following are the common signs and symptoms of oral cancer:

Swellings/thickenings, lumps, bumps, rough spots/crusts/,or eroded areas on the lips, gums, or other areas inside the mouth
The development of velvety white, red, or speckled (white and red) patches in the mouth
Unexplained bleeding in the mouth
Unexplained numbness, loss of feeling, or pain/tenderness in any area of the face, mouth, or neck
Persistent sores on the face, neck, or mouth that bleed easily and do not heal within two weeks
A soreness or feeling that something is caught in the back of the throat
Difficulty chewing or swallowing, speaking, or moving the jaw or tongue
Hoarseness, chronic sore throat, or changes in the voice
Ear pain
A change in the way your teeth or dentures fit together – a change in your "bite"
Dramatic weight loss.
If you notice any of these changes, contact your dentist immediately for a professional examination.

With so many toothpastes in the market today, can you offer any tips to help make a wise choice?
Here’s some advice. First, when purchasing a toothpaste for you or your child, select one that contains fluoride. Toothpastes with fluoride have been shown to prevent cavities. One word of caution: check the manufacturer’s label. Some toothpastes are not recommended in children under age 6. This is because young children swallow toothpaste, and swallowing too much fluoride can lead to tooth discoloration in permanent teeth.

It is also wise to select a product approved by the American Dental Association. The ADA’s Seal of Acceptance means that the product has met ADA criteria for safety and effectiveness, and that packaging and advertising claims are scientifically supported. Some manufacturers choose not to seek the ADA’s Seal of Acceptance. Although these products might be safe and effective, these products’ performance have not been evaluated or endorsed by the ADA.

Next, when considering other properties of toothpaste – such as whitening toothpastes, tartar-control, gum care, desensitizing, etc -- the best advice for selecting among these products might be to simply ask your dental hygienist or dentist what the greatest concerns are for your mouth. Also, be aware that your needs will likely change as you get older. After consulting with your dentist or hygienist about your oral health’s greatest needs, look for products within that category (for example, within the tartar control brands or within the desensitizing toothpaste brands) that have received the ADA Seal of Acceptance.

Finally, some degree of personal preference comes into play. Choose the toothpaste that tastes and feels best. Gel or paste, wintergreen or spearmint all work alike. If you find that certain ingredients are irritating to your teeth, cheeks, or lips, or if your teeth have become more sensitive, or if your mouth is irritated after brushing, try changing toothpastes. If the problem continues, see your dentist.

Since the introduction of fluoride and other advances in dental care and dental products, is it still necessary to visit the dentist twice a year?
The standard recommendation still is to visit your dentist twice a year for check-ups and cleanings. The three best arguments that can still be made to support the twice-yearly visitation schedule are:

So that your dentist can check for problems that you might not see or feel
To allow your dentist to find early signs of decay (Decay doesn’t become visible or cause pain until it reaches more advanced stages.)
To treat any other oral health problems found (Generally, the earlier a problem is found, the more manageable it is.)
That being said, however, people who have taken great care of their teeth and gums, and have gone years without any problems whatsoever might choose to lengthen the time between visits. Ask your dentist what visitation schedule works best for your state of dental health.

At the other extreme, it should be kept in mind that some people — such as some people with gum disease, a genetic predisposition for plaque build-up or cavities, or a weakened immune system —  might need to visit the dentist even more frequently than twice a year for optimal care.

I’m on a limited, fixed income and can’t afford regular dental care. Are there some resources available to me?
Yes. Thousands of dentists across the country offer their services at reduced fees through dental society-sponsored assistance programs. Since aid varies from one community to another, call your local dental society for information about where you can find the nearest assistance programs and low-cost care locations (such as public health clinics and dental school clinics).

Check your local phone book or the internet site for your local dental society. (Check under [name of state] dental society or [name of state] dental association, or county or region dental society or association).

The ADA’s website provides links to state dental associations, local societies, and state dental schools. Ask your dentist or call your local social service organization for assistance in locating these types of services in your local community.

I recently moved and am in need of finding a new dentist. How should I go about this task?
The ADA offers these suggestions:

Ask family, friends, neighbors, or co-workers for their recommendations.
Ask your family doctor or local pharmacist.
If you're moving, your current dentist might be able to make a recommendation.
Call or write your local or state dental society. Your local and state dental societies also might be listed in the telephone directory under "dentists" or "associations." The ADA provides a list of local and state dental societies on their website.
A few other online dentist directories you might try include:

DDS4U Dentist Directory (http://www.dds4u.com)
American’s Finest Dentist Directory (http://www.afdd.com/index.htm)
Dentistinfo.com (http://www.dentistinfo.com)
Dentist Directory (http://www.dentistdirectory.com/)
The ADA suggests calling or visiting more than one dentist before selecting one with whom you feel you can build a good long-term relationship.

What should I look for when choosing a dentist?
You and your dentist will be long-term oral health care partners; therefore you need to find someone with whom you can be comfortable.  To find a suitable dentist to meet your needs, consider asking the following questions as a starting point:

What are the office hours? Are they convenient to meet your schedule?
Is the office easy to get to from work or home?
Where was the dentist educated and trained?
What’s the dentist’s approach to preventive dentistry?
How often does the dentist attend conferences and continuing education workshops?
What type of anesthesia is the dentist certified to administer to help you relax and feel more comfortable during any necessary dental treatment?
What arrangements are made for handling emergencies outside of office hours? (Most dentists make arrangements with a colleague or emergency referral service if they are unable to tend to emergencies.)
Is information provided about all fees and payment plans before treatment is scheduled? (If you are comparison shopping, ask for estimates on some common procedures such as full-mouth X-rays, oral exam and cleaning, and filling a cavity.)
Does the dentist participate in your dental health plan?
What is the dentist’s office policy on missed appointments?
How safe are dental X-rays?
Exposure to all sources of radiation — including the sun, minerals in the soil, appliances in your home, and dental X-rays — can damage the body’s tissues and cells, and can lead to the development of cancer in some instances. Fortunately, the dose of radiation you are exposed to during the taking of X-rays is extremely small.

Advances in dentistry over the years have lead to the low radiation levels emitted by today’s X-rays. Some of the improvements are new X-ray machines that limit the radiation beam to the small area being X-rayed, higher speed X-ray films that require shorter exposure time compared with older film speeds to get the same results, and the use of film holders that keep the film in place in the mouth (which prevents the film from slipping and the need for repeat X-rays and additional radiation exposure). Also, the use of lead-lined, full-body aprons protects the body from stray radiation (though this is almost non-existent with the modern dental X-ray machines). In addition, federal law requires that X-ray machines be checked for accuracy and safety every two years. Some states require more frequent checks.

Even with these advancements in safety, it should be kept in mind, however, that the effects of radiation are added together over a lifetime. So every little bit of radiation you receive from all sources counts.

Are women more prone to oral health problems?
Yes. Women have an increased sensitivity to oral health problems because of the unique hormonal changes they experience. These hormonal changes not only affect the blood supply to the gum tissue, but also the body’s response to the toxins that result from plaque build-up. As a result of these changes, women are more prone to the development of periodontal disease at certain stages of their lives, as well as to other oral health problems. The five situations in a women’s life during which hormone fluctuations make them more susceptible to oral health problems are during puberty, the monthly menstruation cycle, when using oral contraceptives, during pregnancy, and at menopause.



  
Is Chloroform Permissible?

  

  
Question: 
  halothane does not work. Is chloroform permissible in endodontic therapy or
  retreatment?
  
Answer: Chloroform is permissible. The
  FDA ban on the material was lifted. The literature has shown that the amount
  of chloroform used in retreatment is unlikely to cause any systemic effects,
  and the amount entering the system from extrusion is negligible. The bottom
  line is that all currently used solvents (xylene, halothane, rectified
  turpentine, chloroform, eucalyptol, etc.) are cytotoxic when in contact with
  cells, but when confined to a canal space, they probably pose only a minimal
  risk. 
  
(Lt Col Harkacz) - May 2003
  
Reference 
Chutich MJ, Kaminski EJ, Miller DA,
  Lautenschlager EP. Risk assessment of the toxicity of solvents of gutta-percha
  used in endodontic retreatment. J Endod 1998;24:213-216.

  
Cross compatibility of Resin
  Composites and Dentin Bonding Agents 
  
Question: Our clinic has the 3M's
  Scotchbond Multi-Purpose Adhesive Plus as our primary bonding product. Do we
  need to use 3M's composite resin with it or can we use another company's
  composite if we want to?
  
Answer: This is a question that I
  frequently receive  and it is an important one. Quite commonly,
  representatives from dental product companies will encourage you to purchase
  their company's bonding agent and resin composite by claiming
  that the result will not be as good if you don't. In other words, they say
  that using their bonding agent with a competitor's resin composite (or vice
  versa) will produce an inferior result. The research, however, does not
  support this claim. No clear evidence exists that using a bonding agent from
  one manufacturer with a resin composite from a different manufacturer has an
  adverse effect on parameters such as microleakage1 or bond
  strength.2,3 Evidence does exist that appears to show a difference
  in bond strength between resin composites, which has led some researchers to
  recommend using the same manufacturer's resin composite and bonding
  agent.4 The differences, however, may well be due to differences in
  strength between the types of resin composites5,6 (eg, hybrids
  versus microfills) rather than a result of compatibility differences between
  bonding agents and resins. Likewise, a difference in microleakage found in one
  study was attributed to the resin composite type rather than
  brand.1 
  
References 
1. Crim GA. Influence of
  bonding agents and composites on microleakage. J Prosthet Dent
  1989;61:571-574. 
2. Chan DCN, Reinhardt JW, Boyer DB. Composite resin
  compatibility and bond longevity of a dentin bonding agent. J Dent Res
  1985;64:1402-1404. 
3. Baker JF,
  Murchison DF, Charlton DG, Vandewalle K. Cross compatibility of
  fifth-generation dentin bonding and composite systems [Abstract]. J Dent Res
  1998;77:132. 
4. Leirskar J, Øilo G, Nordbø H. In vitro shear bond strength
  of two resin composites to dentin with five different dentin adhesives.
  Quintessence Int 1998;29:787-792. 
5. Perdigao J, Swift EJ, Cloe BC.
  Effects of etchants, surface moisture, and resin composite on dentin bond
  strengths. Am J Dent 1993;6:61-64. 
6. Hasegawa T, Itoh K, Koike T,
  Yukitani W, Hisamitsu H, Wakumoto S, Fujishima A. Effect of mechanical
  properties of resin composites on the efficacy of the dentin bonding system.
  Oper Dent 1999;24:323-330.
  
(Col Charlton) - Jan 2000

  
Minimizing Bubbles in Investments and
  Stone 
  
Question:How can I eliminate bubbles in
  my casts and investment? I have perfected my technique and am using the best
  fine-grain investments and stones. Is there anything else I can do to minimize
  or eliminate bubbles? 
  
Answer: Assuming you have done everything
  possible to reduce bubbles and your vacuum investor is working properly, there
  is a rather simple thing you can do. Place the investment ring or poured
  impression in a dry pressure pot. Bubbles in artificial stones and fine-grain
  investments show significant reduction in the number and size of bubbles when
  allowed to set under pressure of 30 psi. Coarse-grain investments require 80
  psi or higher to reduce bubbles. Pour some test samples, let them set under
  pressure, cut them in half, and then compare them to bench set samples. 
  - (MSgt Ryerson)  - Jan 2000

  
Captek Alloy System 
  
Question: I hear there is a material that
  you can use to form metal-ceramic substructures without investing or casting.
  Do you have any information on this material?
  
Answer: Captek is an alloy system that
  eliminates the need for investing, burning out, and casting normally used to
  fabricate crown and bridge substructures with traditional metal-ceramic
  alloys. Captek uses a refractory die and a noble metal-impregnated wax to
  produce substructures for metal-ceramic restorations. The Captek substructure
  is made by pressing a gold-platinum-palladium impregnated wax (CAPTEK P) to
  the refractory die and trimming it at the margins. It is then fired in the
  porcelain furnace at 1967°F (1075°C) which causes molecular particles to join,
  creating a three-dimensional network of capillaries. A layer of
  gold-impregnated wax (CAPTEK G) is then pressed onto the substructure, trimmed
  at the margins, and fired at the same temperature. The heat treatment draws
  the "G" layer of gold into the capillaries. (A typical framework is shown in
  Figure 1.) The manufacturer recommends applying a thin layer of bonding agent
  called Capbond prior to applying porcelain.
  
 This technology was developed 12 years ago and has
  been commercially available for the last 10 years. The manufacturer claims
  several advantages for it. First, the substructure is purported to be
  biocompatible and corrosion resistant. Second, it is reported to be extremely
  strong, so margins can be reduced to a thickness of only 0.1 mm. The
  manufacturer recommends metal margins be used (see Figure 2 which is a mirror
  view of a finished Captek restoration showing the circumferential margins).
  Because the substructure has a gold color and lacks a gray oxide coating,
  subgingival facial margins appear esthetic. Interestingly, some research
  indicates that a "bacterial inhibition zone" is present at the Captek
  substructure margins.1 Plaque accumulations have been observed to
  be reduced by 90% in these areas compared to adjacent natural teeth. The
  manufacturer also claims that the stress-free construction of Captek
  substructures make the finished restoration more resistant to impact, load,
  and fatigue. Finally, the Captek company claims that the budget projections of
  laboratories using this material are simplified because the material itself is
  price stable (assuming gold remains less than $400/Troy ounce). 
  
Naturally, as with any technology, substantial research
  must be performed to confirm or refute the many advantages claimed for the
  Captek system by its manufacturer. It should be noted that long-term clinical
  studies have not yet appeared in refereed journals that evaluate the
  performance of the Captek system. When they do, clinicians and technicians
  will be able to assess the value and clinical success of the product.
  
  
Reference 
1. Goodson M, Shohert I,
  Imbert S, Som S. Captek alloy reduces dental plaque accumulation [Abstract]. J
  Dent Res 1999;78:262.
  
(MSgt Ryerson) - jan 2000
The Frustrations
of Making Provisionals: Have Manufacturers Made it Any
Easier?
Question: Are there any new materials on
the market for making temporary crown and bridges?
Answer: Over the last few years,
dental product manufacturers have spent a great deal of time and money
developing provisional (i.e., temporary) crown and bridge products that are
easier to use and have better physical properties. Standard acrylic-type
provisional products have been the mainstay of dentistry since the 1930s and
have, for the most part, worked satisfactorily. Products such as Jet Tooth Shade
(Lang), Snap (Parkell), and Trim II (HJ Bosworth) are popular because of their
low cost, acceptable esthetics, and versatility. These products come as two-part
systems (a powder and a liquid) that are mixed immediately before use.
Generally, they are best used for making short-term provisionals that will be
needed for only a few months at most. They have several disadvantages, however.
Among their drawbacks are an objectionable odor, significant shrinkage, heat
production during setting, and a tendency to discolor. To address these
shortcomings, manufacturers have begun producing provisional products that are
bis-acryl resin composites. These materials shrink less (and therefore fit
better), give off less heat, and can be polished at chairside. They don't polish
to as high a luster as the acrylics and often have an air-inhibited layer
following setting, which needs to be removed prior to finishing and polishing.
They also tend to be brittle, so close attention must be paid to the occlusion
if they are used to make long-span bridges. Many of these products are packaged
in cartridges and mixed/dispensed using an automix gun. The bis-acryl composites
polymerize (i.e., harden) in one of several ways: by chemicals (e.g., Integrity,
Dentsply/Caulk; Temphase, SDS/Kerr; Protemp 3 Garant, 3M ESPE); by visible light
(Revotek LC, GC America); or by both chemicals and light (Unifast LC GC
America). These products generally perform very well, and differences among them
primarily center around setting and working times, cost, and packaging form.
(Col Charlton) - May 2003



The Numbers: Is
That All There is to It? 

Question: All the ads for dentin bonding
products contain claims about their bond strengths. Is this an important thing
and should I base my decision to buy the product on it?
Answer: You're right in that
manufacturers commonly tout the bonding ability of their products by featuring
the product's shear bond strength to dentin. Often, they provide a chart and
compare their product to other popular bonding agents. Obviously, they are
depending on you to think higher is always better. Bond strengths are just one
of many factors you should look at when deciding to buy a bonding product. In
fact, it may be one of the less important ones. Let's look at how bond strength
is measured. The test to measure shear bond strength is done by using the
bonding agent to bond a cylinder of resin composite to the ground dentin surface
of an extracted tooth. After storage in water (and possible cycling between hot
water and cold water baths), the amount of force required to shear the composite
cylinder from the dentin is measured. The average number for the group of
specimens is then calculated and represents the "shear bond strength." As you
can see, this laboratory test is only a rough approximation of what we need the
bonding product to do intraorally. What it will be required to do in bonding a
composite restoration to a tooth depends on many factors, including the size of
the restoration, amount and type of dentin and enamel to which it will be
bonded, the forces applied to the restoration, and the appropriateness of the
technique used to apply the adhesive. So, the way to interpret the numbers given
in an ad for a bonding agent is first to keep in mind that lab tests are only a
screening test. They provide a rough idea as to how the bonding product compares
to other similar products, and are most valuable in identifying products that
significantly underperform. You should also be aware that just having the bond
strength number alone doesn't tell the whole story. It is also important, for
example, to know where the failure happened (e.g., between the adhesive and
tooth, within the tooth, within the composite. etc.) because this tells
something about the significance of the numbers. Finally, you should also
remember that the numbers are only going to be featured by manufacturers when
their products outperform their competitor's products. In other words,
regardless of the number, the company that is advertising will always compare
its product to competing brands which have not performed as well.
The bottom line is that bond strength is only one factor
(and perhaps a minor one) to consider. More important factors are how the
adhesive has performed in clinical studies, and the product's ease of use, cost,
and range of clinical uses. DIS has evaluated more than 20 bonding products over
the past few years and serves as a source of current information about these
products. Please call us with any questions you have on selecting or using a
dentin bonding agent.
(Col Charlton) - May 2003

You've Got to Heat It
to Believe It! 

Question: Newly arriving dental officers
have requested the purchase of Obtura II and System B gutta-percha systems. Do
you have any information on this equipment?
Answer: Obtura II is an injectable
gutta-percha system whereas System B uses a heated-tip to soften gutta-percha
points placed in the canal. Two totally-different injectable thermoplasticized
gutta-percha systems are currently available - Obtura II (Spartan Co., Fenton,
MS) and Ultrafil (Hygienic Corp., Akron, OH). Obtura II is a heated-gun system,
whereby gutta-percha sticks are placed within a chamber in the gun, and a
plunger is used to express the heated, flowing gutta percha through replaceable
injection tips. The flow of the gutta percha is controlled through the
temperature of the unit - the higher the temperature, the easier the flow. By
design, the system is considered a "high heat" system, because the gutta percha
provided by Spartan flows best at about 200 degrees C. You can buy "low-heat"
gutta percha from other companies, which allows the gutta percha to flow at a
lower temperature. The system consists of a gun connected to a
temperature-control unit. The unit requires high maintenance because you must
clean it after every use by submerging the nose of the gun in solvent and using
a brush to clean out the chamber/plunger assembly. The gun itself is hot to
touch, and to minimize risk when contacting the patient lips, special
plastic-protective sleeves are slipped over the end of the gun. Obtura II is
primarily used for backfilling canals with apical plugs. Canals without some
form of apical plug/constriction could result in overextrusion of the gutta
percha. Most of the literature seems to show that the high temperature is not
detrimental to the periodontal ligament as long as the heated tip is not left in
the canal for extended periods. The gutta percha cools fairly quickly, and to
counteract shrinkage, must be condensed during cooling. The system allows
continuous heat, so the gutta percha stays soft as long as the unit remains
active. 
In contrast, Ultrafil uses a pre-dosed cannula system.
Cannulas containing various types of gutta percha are placed in a heating unit.
When needed they are loaded into a gun (similar to a periodontal ligament
injection unit), which expresses gutta percha from the cannula. The system is
characterized as a "low-heat" unit, since the temperature needed to plasticize
the gutta percha is much lower than the Obtura II system. Ultrafil has several
advantages. The cannulas are disposable, the injection gun may be sterilized,
and the heating unit is easily cleaned. Three types of gutta percha are
available, which vary by firmness and length of working time, allowing the
practitioner to tailor the type of gutta percha for a specific procedure. A
disadvantage of the Ultrafil system is that it takes about fifteen minutes to
get the cannulas to temperature, compared to the Obtura system, which only takes
about one minute. Overall, the versatile Ultrafil system requires less counter
space and the various types of unit-dose gutta-percha cannulas allows for better
infection control. However, the cannula system is more expensive and if you are
performing extensive backfilling, the Obtura II may be more cost effective.

System B (SybronEndo, Orange, CA) is not a injection
technique, but rather a heated tip used to soften gutta-percha points placed in
the canal. It follows the "continuous-wave" concept advocated by Steve Buchanan.
In principle, you take a plugger tip and insert it in your prepared canal. The
plugger tip needs to bind about 5-mm from your working length. A gutta-percha
cone is then fit to length in the canal. The plugger tip with the System B is
heated to a high temperature. Temperature and power is controlled digitally on
the unit. The heated plugger is then inserted into the canal, melting the
gutta-percha cone on insertion and creating a leading front (or wave) of heated
gutta percha. When you get close to your binding point, the heat is
discontinued, but apical pressure is continued to condense the now softened
gutta percha and conteract any contraction during cooling. After a few seconds,
the tip is activated for one second (high heat, short burst) and pulled back to
remove excess gutta percha. The coronal space is then usually backfilled with a
softened gutta-percha system. 
Unless you have excellent apical control, these systems will
lead to overfill of material past the apex and potential problems of apical
periodontitis. In skilled hands, it is another tool for obturation. Practice on
extracted teeth first before attempting the technique on patients. Be careful in
canals which have apical lesions, resorptions, or open apices, as these clinical
situations are not good candidates. 
(Lt Col Harkacz) - May 2003

Just Seal It!

Question: A wide variety of sealants are
available, from filled to colored to fluoride-containing. Are there really any
differences?
Answer: Surprisingly, research has
found that unfilled sealants perform as well as or better than filled sealants.
Studies have found that unfilled sealants are significantly better
retained1,2 and have less microleakage3 than filled
sealants. Although potentially more difficult to control during placement, the
lower viscosity of the unfilled sealants allows them to penetrate deeper into
the fissure system.4 Filled sealants may provide better mechanical
properties and therefore less wear, but they suffer from a potential need for
occlusal adjustment as part of the application procedure. If an unfilled sealant
is left in occlusion, it will usually abrade rapidly.4 However, one
study found that with filled sealants, most patients were unable to abrade the
interferences to a comfortable level.5 Also, reduction in wear may
not be as clinically significant as penetration when evaluating the sealing and
retentive abilities of a sealant in the deeper depths of a pit or
fissure.4
Colored sealants are easier to see during application and at
recall examinations. A study by Rock and others found the error rate in
identifying a sealant was 22.8% for a clear resin and only 1.4% for an opaque
resin.6 The latest marketing trend is to incorporate color-change
chemistry into the sealant to make it easier to see during placement. One
example is a product recently evaluated by DIS called Clinpro, a new fluoride-containing, light-activated pit and
fissure sealant by 3M ESPE. Clinpro is pink when expressed from its delivery
syringe and turns white following light activation. 
While no one will argue against the substantial advantages
of fluoride in caries prevention, it has been difficult to unequivocally prove
any significant reduction in caries with the use of fluoride-releasing
restorative materials. The actual fluoride release of fluoride-releasing
resin-composite restorative materials and sealants is among the lowest of all
the fluoride-releasing materials manufactured.7 No studies have
documented a caries reduction due to fluoride in fluoride-releasing sealants,
raising serious doubts about any clinical significance. The addition of fluoride
is probably more of a marketing benefit than a clinical
advantage.4
Finally, the introduction of light-activated sealants many
years ago provided the advantages of command set, the ease of non-mixing, and
fewer voids compared to autopolymerizing materials. However, De Craene and
others found no significant difference in terms of retention or caries
prevention between self-cured and visible light-cured
sealants.8
(Col Vandewalle) - May 2003
References
1. Barrie AM, Stephan KW, Kay EJ.
Fissure sealant retention: a comparison of three sealant types under field
conditions. Community Dent Health 1990;7:273-277. 
2.
Rock WP, Weatherill S, Anderson RJ. Retention of three fissure sealant resins.
The effects of etching agent and curing method. Results over 3 years. Br Dent J
1990;168:323-325. 
3. Hatibovic-Kofman S, Wright GZ, Braverman I.
Microleakage of sealants after conventional, bur, and air-abrasion preparation
of pits and fissures. Pediatr Dent 1998;20:173-178. 
4. Simonsen RJ. Pit and
fissure sealant: review of the literature. Pediatr Dent 2002;24:393-414. 
5.
Tilliss TS, Stach DJ, Hatch RA, Cross-Poline GN. Occlusal discrepancies after
sealant therapy. J Prosthet Dent 1992;68:223-228. 
6. Rock WP, Potts AJ,
Marchment MD, Clayton-Smith AJ, Galuszka MA. The visibility of clear and opaque
fissure sealants. Br Dent J 1989;167:395-396. 
7. Garcia-Godoy F, Abarzua I,
De Goes MF, Chan DC. Fluoride release from fissure sealants. J Clin Pediatr Dent
1997;22:45-49. 
8. De Craene GP, Martens LC, Dermaut LR, Surmont PA. A
clinical evaluation of a light-cured fissure sealant (Helioseal). ASDC J Dent
Child 1989;56:97-102.
I Can't Wait
'till You Obturate!
Question: Do you have any information on
the Thermafil Plus system? Our clinic is considering its purchase. 
Answer: Thermafil Plus
(Dentsply Tulsa Dental, Milford, DE) is a system where plastic carriers are
coated with alpha-phase gutta percha. The carrier/gutta percha is heated in an
oven to plasticize the outer gutta perch, then inserted in the canal to length.
During the insertion, the warm outer gutta percha flows into all the anatomic
variances of the canal. An entire system is devoted to this method of
obturation, to include size verifiers, obturators, an oven, and an epoxy
endodontic sealer. The plastic carrier core has a groove to promote backflow of
excess gutta percha during insertion, and to facilitate retreatment by providing
an area for instrument insertion to loosen and remove the carrier. 
Advantages of the system are ease of use, good
three-dimensional fill, and quick obturation. Disadvantages are questionable
apical seal, difficulty in retreatment and problematic post-space preparation.
Sometimes the gutta percha will strip off the carrier to bare plastic by the
time the carrier is at working length. However, the clinical significance of
this remains unknown. Also, if you have a patent apical foramen, there is a good
chance you will extrude softened gutta percha, sealer, or both. The carrier may
be difficult to remove during retreatment. Also, creating post space is
technique sensitive. You have to remove gutta percha and carrier for post space
without disturbing the apical seal, which may be very difficult with this
system. 
The Thermafil Plus system is an acceptable method of
obturation, but may not offer any big advantage over conventional lateral
condensation. The system is more expensive when including the cost of the oven,
carriers and nickel-titanium sizers. Whether a three-dimensional gutta percha
fill is clinically superior to lateral condensation with sealer fill has yet to
be proven. If stationed overseas, getting supplies in a timely manner is an
additional concern. Once you have purchased the system, you are obligated to use
the system's gutta-percha carriers and products, whereas standard gutta-percha
cones with eugenol sealer can be purchased anywhere fairly quickly.
(Lt Col Harkacz) - May 2003
Best solution to save the extracted tooth
Question: Today I have started to save all the extrated teeth to practise with the rotatory instrumentation but....Which is the best solution to save them? They told me that bleach is not a good one as it makes the tooth weak.
Alcohol? Clorhexidine? - Marcela (ROOTS) 30th June 2006

Answer:in NaOCl for 15 min then stored in saline with a bit of clorhexidine mouthrinse-JL

I would put it in Chlorexidine+Cetrimide solution which is availble as hospital concentrate disinfectant.
It's been quite good with me foe keeping those abnormally shaped tooth that we extract - Ananya