SYDNEY DENTAL GLOSSARY
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In our teen years we are not overly confident and going through puberty can be difficult
Your teeth can also be susceptible to problems having to cope with sugary foods and drinks, Trauma from contact sports (see Mouthgaurds) and rough play and of course overcrowding (see Orthodontics)
Peer group pressure can make it harder still
To have healthy teeth and mouths we need to practice correct Tooth Brushing technique and follow Health Diet
In excess Soft Drinkssuch as Coca Colacan cause:
- Acidic Erosion of teeth
- Decay from Sugar
- Other systemic health problems such as diabetes, osteoporosis and obesity
Healthy teeth contribute to an attractive smile. We all would like that lovely smile.
Remember that it is the first three years of a tooth’s life that are by far the most important. If a tooth can successfully survive these three years without damage from acid then chances are it will never decay. In fact without Pathology (Gum Disease, Decay or Grinding) teeth are built to last more than a lifetime
Q: Is fever a symptom of teething in babies?
A: No. Research shows significant fever is not a symptom of teething.
Our expert: Professor Melissa Wake
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There's no shortage of advice for new parents and it seems everyone has an opinion on every aspect of parenting – including teething.
New parents often hear tales of miserable babies' terrible teething experiences. These experiences include anything from irritability, drooling, red cheeks and nappy rash; to diarrhoea, sleep disturbances, infections and even fever.
But is fever really a common symptom of teething in babies?
Research suggests not, and Professor Melissa Wake, associate director of research for the Centre for Community Child Health at the Royal Children's Hospital in Melbourne, says parents should never assume that their baby's fever is related to teething.
In the late 1990s, Wake led a seven-month teething study at a number of Australian day care centres. Each morning, parents reported any 'teething symptoms' they'd noticed since the previous morning. At midday, a dentist checked the baby's mouth for signs of new teeth coming through and took the baby's temperature – but didn't tell the parents or carers. In the afternoon, carers reported any daytime symptoms.
The researchers found the babies didn't experience any significant increase in temperature when they were teething. (A fever is considered any temperature over 38°Celsius.) Researchers also failed to find any significant association between teething and some of the symptoms commonly associated with teething babies, such as sleep disturbances, congestion, changes to bowel movements, and infections.
However, a US study did find some short-term links between teething and increased biting, drooling, gum-rubbing, irritability, wakefulness, ear-rubbing, facial rash and a decreased appetite for solid foods.
Why the link?
So why do so many parents, and even some medical professionals, continue to believe that fever is a common symptom of teething?
Wake says most infants and young children start teething between four and 24 months old. This time frame roughly coincides with the period, between six and 24 months, when young children experience most of their infections. And infections (especially viral ones) are the most common cause of fevers in young children.
Babies start to get more infections from around six months of age, Wake says, when there is a decline in antibodies that they receive from their mother.
Given that most children get scores of infections and 20 teeth during the first three years of life, it's hardly surprising that these two events often coincide.
Another point Wake makes is that primary school aged children also get many new teeth – but they don't seem to complain of the side-effects that parents report in infants.
While parents may find it reassuring to attribute symptoms, such as a fever or a sleeping difficulty, to teething, this is not a good idea.
There is the possibility that parents could overlook an illness that needs medical attention and treatment. Fever can be a symptom of mild infections, such as a cold, flu, stomach bug, but it can also be a symptom of something more serious, such as pneumonia or a urinary tract infection. So, if a baby has a fever, and parents feel concerned then they should always see a doctor.
Also if a baby with an infection continues to mix with other children then they can spread the infection.
Similarly, parents may ignore certain developmental issues and not get relevant expert advice. For example, some babies develop sleep problems at around eight to 10-months-old. If these are addressed promptly they are often sorted out easily. Putting sleep problems down to teething may mean parents don't get help for sleep problems their baby is having, which means months poor sleep for both parents and the baby. (This situation can sometimes lead to maternal depression, which further affects the baby.)
Also erroneously linking symptoms to teething can lead to an overuse of pain-relieving medications and oral gels; this is especially a concern over longer periods, Wake says.
"No one wants babies to be taking unnecessary medication." (For more information on babies and pain relievers see fact buster on pain killers)
Treating teething symptoms
But there is at least some research to suggest teething does make babies irritable or more inclined to want to mouth or bite things and rub their gums.
In these cases you can try giving your baby something appropriate to chew on – such as a cold teething ring or rusk – this may or may not relieve the baby's apparent discomfort, but it's unlikely to cause any harm.
Most importantly, if your baby has a fever and seems unwell – whether teething or not – then you should probably take them to the doctor.
Professor Melissa Wake is the associate director of the Centre for Community Child Health at the Royal Children's Hospital in Melbourne. She spoke to Callista Cooper.
- TheTemporoMandibularJoint(TMJ) connects themandible to the skull and involves:
- Muscles and Tendons
- Ligamentsand Cartilage especially the Articular Disc between the bones
- Connective Tissuesand
- Nerves(Trigeminal Nerve)
- The TMJ allows the mandible to rotate and also to translate or slide forwards
- TMDis a broad term andrefers to both chronic and acuteinflamation of the joint
- Symptoms associated with TMJ disorders may be:
- Biting or chewing difficulty or discomfort
- Clicking, popping, or grating sound when opening or closing the mouth
- Jaw pain or tenderness of the jaw
- Dull, aching pain in the face
- Reduced ability to open or close the mouth
- Earache (particularly in the morning) in upto 50 % of cases
- Headache (particularly in the morning)
- Migraine (particularly in the morning)
- Tinnitus– sounds or ringing in the ear
- Hearing loss
- Neck and shoulder pain
- Signs of TMD are usually a resultof:
- Pain – may be localised or vague
- Swelling around the joint
- Pain on tissue palpation
- Deviations in jaw movements due to muscle reflex cramping
- Limitations in jaw movements if cramping is more severe
- Evidence of bone and cartilage wear sometimes seen
- Signs and Symptoms are usually a result of:
- Direct Nerve Compression if the Articular Disc is displaced from its position
- Local inflammation of surrounding tissues (point # 1)
- DistantNeuro Muscular effects
- Reffered Pain
- Causes most commonly involve:
- Effects from Injury or Trauma– egaccidents, blows to the jaw, dislocations and very difficultwisdom teeth removal -- account for 10 – 30% (Pullinger et al 1985)
- Stress-Related Muscle Dysfunction:
- Bruxism -- repetitive unconscious clenching or grinding of teeth, often at night is seen in 10 to 30% of cases (Reding et al 1966; Glaros 1981; Rugh and Harlan 1988; Rugh and Ohrbach 1988) and
- Other unusualJaw Habits and Repetitive ParafunctionalBehaviors– very often have a Psychologicalcomponentand may be difficult to diagnose – 24 to 38% (Oakleys et al 1989)
- Degenerative Disease in particular Polyarthritis –about 5% (Irby and Zetz 1983)
- Joint Hypermobilityor Laxity – between 3 – 25% (Westling 1989)
- Malocclusions or bite problems – not commonly a cause (G.ClarkeEtiologic Theory and the Prevention of Temporomandibular DisordersAdv Dent Res 5:60-66, December, 1991)
Note that genetic anatomical susceptibility to damage may be a significant factor in some of these causes
- Treatment must first involve an accurate diagnosis as the causes are many and varied.TMD is most often Multi Factorial
- Treatment options include:
- Flat Plane Occlusal Splints(Night Guards) to reduce nighttime clenching
- Mandibular Repositioning Devices which move the jaw, ligaments and muscles into a new position
- Eliminating Negative Oral Habits
- Alleviating bad Head and Neck Posture
- Nighttime Biofeedback Headband for Para-Functional Habit Modification
- MyofunctionalPhysical Therapy – Stretching and Relaxation Protocols
- Hypnotherapy and other Stress Management Therapies
- h) Reconstructive dentistry including improving jaw support and restoring lost Vertical Dimension
- Botox injections to muscles involved
- Arthrocentesis– jaw manipulation and joint irrigation with saline and anti-inflammatory solution under general anaesthesia
- Surgical repositoning of jaws to correct congenital jaw malformations such as prognathism and retrognathia
- Replacement of the Jaw Joint or Disc with Implants– usually a treatment of last resort
Cleaning the 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.
GC “Tooth Mousse” conditioner . This product is an Australian breakthrough in tooth remineralisation. Taken on by the Japanese firm GC it sets the bar in oral health mineral research.
Surface stains (also known as extrinsic stains) are superficial stains located on the surface of the tooth. They include:
- coloured plaque (yes plaque comes in a variety of colours, usually yellow but also red, orange, brown and even green)
- tars from tobacco and cannabis
- tannins from teas, coffee and vegetables
- coloured foods
- some dental mouthwashes (containing chlorhexidine eg Savacol)
These surface stains require dental plaqueas a matrix or base in order for them to form. That is, plaque that is not removed from the tooth surface can act as a “sponge” to absorb the pigments which then hardens as calculus forms from free floating calcium present in the saliva.
Internal stains (also known as intrinsicstains) are coloured molecules and pigments that have become incorporated into the internal structure of the tooth. This can occur as the tooth is developing, or after the tooth has been present in the mouth. Some fifty conditions have been associated with changes to tooth structure as it forms.
Examples of these developmental discolourations include:
- Severe illnesses and fevers in childhood
- Antibiotics such as tetracyclines taken in childhood
- Uncommon genetic conditions where there is a pattern of inheritance
- Medical conditions affecting the blood system or liver in childhood
- Excessive levels of fluoride intake in early childhood because of swallowing toothpaste, which can result in areas of whiteness (opacity) or brown mottling if excess.
Conditions which can lead to internal colour changes in teeth that have already erupted in the mouth include:
- Advancing age, which leads to greater yellow colouration of teeth as the nerve of the tooth shrinks and lays down more dentine.
- Corrosion products from amalgam restorations, which can give grey stains
- Tooth decay
- Problems with the dental pulp (“nerve”), after decay, root canal work, or damage to the tooth in an injury.
Teeth contain a mixture of yellow, red and grey colours, and between individuals there is a wide range of tooth shades
It is normal for teeth to darken with age
Other Causes of Tooth Staining
Tooth color can change with age, as tooth enamel thins and allows more of the darker under layer, or dentin, to show. Certain medicines can also affect tooth color, such as tetracycline and other antibiotics.
You can limit further staining by drinking fewer dark colored beverages. Your dentist can advise you on treatment methods for current discoloration.
For teeth that are extremely badly stained, your dentist might recommend using porcelain veneers. Veneers, which are custom made, are permanently bonded to your teeth. While dark-colored beverages can also stain veneers over time, this treatment does offer patients another opportunity for a bright smile
How are surface stains treated?
There are at least 3 options to consider:
- Surface stains can be removed by a dentist or dental hygienist using a number of cleaning and polishing methods. This is the quickest method, and it can also achieve “tooth lightening” (see below).
- The second option is to use a whitening toothpaste. These have special abrasives included in the paste which allow them to also remove some surface stain from easy-to-reach surfaces during normal toothbrushing.
- The third option is a paint-on whitening treatment (see below), since these have ingredients which can dissolve surface stains.
Regardless of which option you choose, lifestyle factors need to be considered since surface stains can reform quickly depending on your dietary and other habits.
Internal stains are normally treated using oxygen-releasing chemicals such as peroxides (typically hydrogen peroxide, carbamide peroxide, or sodium percarbonate peroxide) or chlorites which can penetrate into the tooth and give a bleaching effect. A level of 10% carbamide peroxide in the presence of water releases 3.5%, so this numerical relationship must be taken into account if comparing products with carbamide peroxide with similar products containing hydrogen peroxide.
These chemicals can be applied in a variety of ways:
- In an advanced whitening formula toothpaste where special activators are included to enhance the action of peroxides within the toothpaste
- As a paint-on treatment where liquid is applied to the teeth as an at-home treatment
- As adhesive films which are applied to one tooth at a time and left in place overnight
- In a gel applied to the teeth for several hours using a stock tray or a custom-made tray. This is often called “nightguard vital bleaching.”
- As a professional treatment in the dental surgery in which a gel is applied to the teeth and then activated using high intensity lights, lasers or ozone. This is called “power bleaching”.
- For teeth which have already had root canal treatment, whitening materials can be applied internally within the tooth and sealed in place for a longer period of time. This is known as a “walking bleach.”
When staining is inside the tooth, well below the surface, there are a number of other ways to improve the appearance of the teeth. Sometimes simply replacing old, worn out fillings that are failing at the edges can produce better looking front teeth. Alternatively, when the teeth are heavily stained, veneers or crowns may be a useful and better option. ADA dentists have access to continuing education in the latest dental techniques and they can give advice as to the best choices for you.
Professional polishing (“scale and clean”) involves the removal of surface or Extrinsic Stains
This makes teeth reflect more light and thus they appear lighter
To make the teeth lighter than this Tooth Whitening is needed
Serves as an abrasive that aids in removing the dental plaque
Active ingredients such as fluoride or xylitol
Most of the cleaning is achieved by the mechanical action of the toothbrush, and not by the toothpaste.
Salt and Baking soda are among materials that can be substituted for commercial toothpaste.
Toothpaste is not intended to be swallowed.
at least 50% of a typical toothpaste
aluminum hydroxide (Al(OH)3),
calcium carbonate (CaCO3), various
calcium hydrogen phosphates, various
Abrasives, like the dental polishing agents used in dentists' offices, also cause a small amount of enamel erosion which is termed "polishing" action.
powdered white mica which acts as a mild abrasive, and also adds a cosmetically-pleasing glittery shimmer to the paste. The polishing of teeth removes stains from tooth surfaces, but has not been shown to improve dental health over and above the effects of the removal of plaque and calculus.
usually contain sodium lauryl sulfate (SLS) or related surfactants.
found in many other personal care products as well, such as shampoo, and is largely a foaming agent, which lowers surface tension and enables uniform distribution of toothpaste, improving its cleansing power.
colorings, and flavors encourage use of the product.
hree most common flavorants are peppermint, spearmint, and wintergreen.
more exotic flavors include anise, cinnamon, fennel, lavender, neem, , orange,tea tree, eucalytus, menthol
unflavored toothpaste exist.
suppress the tendency of toothpaste to dry into a powder. various sugar alcohols such as glycerol, sorbitol, xylitol, or related derivatives, such as 1,2-propylene glycol and polyethyleneglycol.
Strontium chloride or
arginineare included in some toothpastes to reduce sensitivity
Don’t need it
Don’t swallow it
Fluoride-containing toothpaste can be toxic if swallowed
Much of the fluorosis seen in children and adults may be due to swallowed toothpaste
Children should use only a smear of full strenght toothpaste or preferably use childrens half strenght
Several non-fluoride toothpastes are availableegWeleda, Red Seal
Reports have suggested that triclosan, an active ingredient in many toothpastes, can combine with chlorine in tap water to form chloroform , which the United States Environmental Protection Agency classifies as a probable human carcinogen. An animal study revealed that the chemical might modify hormone regulation, and many other lab researches proved that bacteria might be able to develop resistance to triclosan in a way, which can help them to resist antibiotics also.
Microscopic view of dentine showing tubules responsible for Sensitivity
Fluid movement inside the tubule is responsible for tooth sensitivity. For example a blast of air over the exposed root surfaces dries out fluid at the surface which draws out fluid deeper in. This movement of fluid pulls on the nerve and registers as pain.
Sensitive toothpastes all work by sealing up the surface openings. Sensodyne uses potassium nitrate whereas the Colgate product “Pro Relief” uses the small amino acid Arginine see Toothpastes
Decensitizing Tooth Paste
After more than 20 years of whitening teeth we think we know what are the safest, most comfortable and most effective materials and techniques available. We have three methods:
- In Chair One Visit – Natural + Professional with the advantages of zero to very minimal sensitivity. This is a patented formula with No Heavy Metals and no tooth dehydration.
One hour and a half - $750.
- Take Home – custom fitted trays, one hour a day for two weeks, Natural + Home, No Heavy Metals, patented 6% hydrogen peroxide formula, no sensitivity, latest technology $350. http://www.naturalplusteethwhitening.com/
- Take Home – custom fitted trays, overnight for two weeks, Opalescence USA 10% carbamide peroxide considered the “Gold Standard”, longest duration (10-15% reversal over five years – “permanent”) $350. http://www.opalescence.com
- Discolouration of teeth can be a result of surface/extrinsic stains or subsurface/intrinsic stains
- Extrinsic stains can be polished off whereas intrinsic staining requires either:
A. Bleaching where oxygen liberated from peroxide penetrates Enamel and Dentine to oxidize stains without damaging the tooth or
B. Some form of coverage eg Veneers
- There are three methods of bleaching teeth. All rely on oxygen from peroxides:
- Over the counter kits and toothpastes -- Not Recommended – The solutions used in internet or store bought kits are not as effective and require greater volume to fill up the “one size fits all” trays. Apart from these stock trays being bulky and uncomfortable the result is that the solution covers the gum and causes irritation. Worse still is the sloshing around and overspill with much of the solution being swallowed. Because of this the gels need to be weaker and thus are less effective giving patchy and weak results. Also poorer quality solutions used tend to be acidic and can damage teeth. Whitening toothpastes are either too abrasive and result in damage to teeth and gums or if they have any active peroxide ingredient are way too weak (usually 1%) and are not on the teeth long enough to make any difference.
- Custom made take home tray delivery systems when used overnight are the Gold Standard according to Cochrane Meta Analysis of all properly conducted research. Home bleaching involves wearing very thin, transparent plastic trays called Stints specifically moulded to your teeth, which is used to hold a bleaching agent in contact with the tooth surface for varying periods of time. The bleaching agent is either:
- low concentration hydrogen peroxide eg 5 to 9 % or
- higher concentration carbamide peroxide eg 10 to 30% (which breaks down to hydrogen peroxide in the mouth)
- Rapid in the chair power bleaching eg Natural+ Professional, Zoom or Laser. At
SAS Dental we only perform and recommend Natural+ as this is the only system with
all natural ingredients and zero to no sensitivity. Because there are no heavy metals
there is no “bounce back” due to dehydration. It uses the latest technology to deliver
true neutral pH throughout the procedure
- When using the home systems we generally recommend only using very small amounts (about a sesame seed to match head size for each tooth). The Natural+ Home system has a special delivery system which delivers just the right amount while the Opalescence syringes require careful dispensing of the gel.
- Only the front surfaces of the front 8 or ten teeth need to be done
- As a rule of thumb in order to achieve Facial Harmony we recommend you use the whites of your eyes as a guide to how white you go. Other factors in maintaining harmony are:
- Complexion – can lighten more if you are lighter skinned
- Restorations/fillings present in your mouth as these will not lighten up. This is not an issue if you plan on replacing them though
- Peroxides are very safe to use and are actually naturally produced in the body in small amounts. Hydrogen peroxide (the active agent of whitening systems) is a very simple and small molecule (H2O2) that reacts with bacteria and turns into oxygen and water. Otherwise, four issues can be identified with ToothWhiteningproceduers namely
- Sensitivity generally zero with the newer Natural+ system
- Uneveness see point 9
- Old fillings and crowns do not lighten see point 10
- Bonding after Whitening see point 16
- If sensitivity does occur it is only temporary (1-2 days) and usually occurs where there is exposed dentine such as in gum recession or wear from grinding (see Bruxism). Sensitivity can be minimized by:
- Treating the exposed dentine surfaces prior to beginning treatment either with fillings or Tooth Conditioner (GC “Tooth Mousse” is highly recommended)
- Decrease frequency of use eg every second day especially if alternate with Tooth Mousse. May even take a break and condition.
- Decrease duration to two hours or less as opposed to overnight
- Make sure you use only very small amounts (sesame seed size for each tooth)
- Use Colgate Pro-Relief or Sensodyne tooth pastes
- Maintain optimal Oral Hygiene
- Bring the trays in for an adjustment
- Tooth whitening does not change the colour of dental fillings. After a whitening treatment, it may be necessary to have fillings resurfaced or replaced to match the new shade
- Peroxides elevate the level of oxygen in the outer (Enamel) surface of the tooth, and because this can affect dental bonding, any fillings or veneers on these teeth must be delayed for upto 2 weeks after the end of the bleaching treatment
- Other benefits include:
- Remineralization and strenthening of Enamel and Dentine from the Fluoride in the Opalescence solutions. This is further augmented if ToothMousse is used and
- Antibacterial effect from the oxygen released creating a healthier environment for Gums
- The custom made stints are ideal for later use to deliver otherother medicaments to the teeth such as:
- Tooth Mousse and ClinPro Tooth Conditioners
- Fluoride strengthening pastes
- Decensitizing pastes
- Whitening touch ups
Another issue is seen in teeth where the enamel is not uniform in density. Here, the most porous enamel, usually seen as white opaque spots, whitens first before the more dense, less porous translucent enamel. Also, sometimes the edges of the teeth may whiten first. Again with time the enamel evens out but it is best to ring us if you are unsure
The ideal tooth brush has well dispersed soft bristles on a small head.
Ideally it should used two to three times a day with the whole aim being the removal of as much plaque as possible.
The ideal way to brush is with very small circles and angled into the gum. The application of a moderate amount of pressure is good but care must be taken to keep circles very small.
The very best tooth brushes we have come across are:
- Colgate Sensitive (Switzerland)
- TePe Supreme (Sweden)
- Sensodyne 35
- Colgate Total Professional
- Colgate 360 soft
Is electric good?
What technique should I use massaging gums with toothbrush bristles is generally recommended for good oral health.
- ?as cleaning behind the last tooth, the third molar, in each quarter.
When brushing your teeth it is best to place your toothbrush at a 45-degree angle to your teeth, aiming the bristles of your brush toward the gum line. The join between the teeth and the gum is a nice niche for bacteria and plaque to accumulate, so it is important to get to this area.
Once you have the brush at the correct angle, all you need to do is jiggle the brush gently back and forward, only brushing one or two teeth at a time. Don’t be excessively vigorous but also don’t be too mild.
Remember. Your are trying to penetrate the bristles into the gaps between teeth to remove a very soft plaque.
You need to be systematic – brushing all teeth in order, inside and outside – and you really should do it in front of a mirror so you can see what you are doing.
History various excavations done all over the world, in which chewsticks, tree twigs, bird feathers, animal bones andporcupine quills were recovered. The first toothbrush recorded in history was made in 3000 BC, a twig with a frayed end called a chewstick. Indian medicine (Ayurveda) has used the twigs of the neem or banyan tree to make toothbrushes and other oral-hygiene-related products for millennia. The end of a neem twig is chewed until it is soft and splayed, and it is then used to brush the teeth. In the Muslim world, chewing miswak, or siwak, the roots or twigs of the Arak tree (Salvadorapersica), which have antiseptic properties, is common practice. The usage of miswak dates back at least to the time of the Prophet Muhammad, who pioneered its use. Rubbing baking soda or chalk against the teeth has also been common practice in history.
A photo from 1899 showing the use of toothbrush.
William Addis of England is believed to have produced the first mass-produced toothbrush in 1780. In 1770 he had been jailed for causing a riot; while in prison he decided that the method used to clean teeth – at the time rubbing a rag withsoot and salt on the teeth – could be improved, so he took a small animal bone, drilled small holes in it, obtained some bristles from a guard, tied them in tufts, passed the tufts through the holes on the bone, and glued them. He soon became very wealthy. He died in 1808, and left the business to his eldest son, also called William; the company continues to this day. By 1840 toothbrushes were being mass-produced in England, France, Germany, and Japan. Pig bristle was used for cheaper toothbrushes, and badger hair for the more expensive ones.
The first patent for a toothbrush was by H. N. Wadsworth in 1857 (US Patent No. 18,653) in the United States, but mass production in the USA only started in 1885. The rather advanced design had a bone handle with holes bored into it for the Siberian boar hair bristles. Animal bristle was not an ideal material as it retains bacteria and does not dry well, and the bristles often fell out. In the USA brushing teeth did not become routine until after World War II, when American soldiers had to clean their teeth daily.
synthetic fibers, usually nylon, by DuPont in 1938. The first nylon bristle toothbrush, made with nylon yarn, went on sale on February 24, 1938. The first electric toothbrush, the Broxodent, was invented in Switzerland in 1954.
The ability of a structural material to resist shock or impact; its ability to absorb energy before fracture.
Strength measures the resistance of a material to failure, given by the applied stress (or load per unit area).
Toughness and Strength are related. A material may be strong and tough if it ruptures at high strains exhibiting high forces. The quality known as toughness describes the way a material reacts under sudden impacts Brittle materials may be strong but not tough. Strength indicates how much force the material can support, while toughness indicates how much energy a material can absorb before rupture. In short, the opposite if tough is "brittle." A good example of a tough material that has low strength is rubber. A good example for a strong material that is brittle is porcelain.
Fiber-reinforced composites are so strong that dental bridges made with them can be attached with less invasive techniques to adjacent teeth.
Credit: UC San Diego
Vistasp Karbhari, a professor of structural engineering at UC San Diego, has developed fiber-reinforced polymer composites as strong, lightweight materials for aerospace, automotive, civil and marine applications, so he thought, "If they work so well in highway bridges, why not dental bridges?"
In a paper scheduled for publication in Dental Materials, Karbhari and Howard Strassler, a professor and director of Operative Dentistry at the University of Maryland Dental School, report the results of detailed engineering tests on dental composites containing glass fibers as well as the type of polyethylene fibers used in bullet-proof vests.
Karbhari and Strassler found that the toughness of fiber-reinforced dental materials depends on the type and orientation of the fiber used. Their report, available at the Dental Materials website, shows that braided polyethylene fibers performed the best, boosting toughness by up to 433 percent compared to the composite alone.
Many of the strength and durability tests reported in the paper are not currently required by the U.S. Food and Drug Administration (FDA), which regulates dental composites as class II prescription devices. The agency requires eight minimum tests plus biocompatibility tests to ensure that dental composites are safe and nontoxic.
“Fiber-reinforced composites are now widely used in the aerospace and automotive industries and the experience we’ve gained in these applications can be applied in a more rigorous way in dentistry and medicine to tailor performance to exacting requirements,” said Karbhari. Dentists began using particle filled composites 10 years ago as an alternative to ceramics and mercury-containing metal amalgams. Strassler selected three commercially available fiber-reinforced composites for analysis.
Dental composites made with glass or polyethylene fibers are sold as pliable ribbons that dentists mold into the required shape and then harden with curing lights. “Many reinforcing fibers can add strength and toughness to dental composites,” Karbhari said, “but if they are improperly aligned they could actually accelerate damage to existing teeth.”
“What’s been missing until now is a rigorous, reproducible way to test the durability and resistance to breakage for these materials,” Strassler said. “Makers of fiber-reinforced dental composites need a much better understanding of how their products actually perform as part of a restoration, crown, or bridge, and this study provides an analytical standard with which all composites should be evaluated in the future.”
The three products tested were a 3-millimeter-wide ribbon of unidirectional glass fibers, a 3-millimeter-wide ribbon of polyethylene fibers woven in a figure-8 stop-stitch leno-weave, and a 4-millimeter wide ribbon of polyethylene fibers woven in a biaxial braid. The resistance to breakage and various measures of toughness of the three preparations were compared to the dental composite alone.
“All three fiber fabrics dramatically increased the durability and strength of the dental composite, but the polyethylene fibers braided in a biaxial ribbon performed best,” said Karbhari. “The tests required by the FDA indicate that fiber-reinforced composites are safe, but those tests are only partially informative. Our analyses show that we can optimize these materials to match and improve performance of teeth, for greater durability, toughness, and resistance to breakage.”
Strength Vs Toughness
What if I get my teeth knocked out?
The upper front permanent teeth are the most common teeth to be completely knocked out. Knocked out baby or primary teeth are usually not reimplanted in the mouth, since they will be naturally replaced by permanent teeth later. However, knocked out permanent teeth should be retrieved, kept moist, and placed back into their sockets (reimplanted) as soon as possible. The most important variable affecting the success of reimplantation is the amount of time that the tooth is out of its socket. Teeth reimplanted within one hour of the accident frequently reattach to their teeth sockets.
The knocked out tooth is rinsed in clean water or milk and placed back (reimplanted) into the socket from which it came. This can be done by the patient or parent and then checked by the dentist. Care should be taken to handle the tooth only by its crown and not by its root. If the parent or patient is unsure about reimplanting the tooth, then the tooth should be stored in milk (if available) or in water and brought to the dentist as soon as possible. Alternatively, in older children and adults who are calm, the tooth may be held within the cheeks inside of the mouth while traveling to the dental office.
After reimplanting the tooth into its original socket, the dentist can then splint this tooth to adjacent teeth for two to eight weeks. Splinting helps to stabilize it while the bone around it heals. During the splinting period, the patient eats soft foods, avoids biting on the splinted teeth, and brushes all the other teeth diligently to keep the mouth as clean as possible.
In adults, the reimplanted tooth should have a root canal procedure within seven to 10 days. On the other hand, reimplanted permanent teeth in children (where the tooth root has not yet completely formed) may not need a root canal procedure. These teeth are observed for at least five years for symptoms of dying pulp, such as pain, discoloration, gum abscesses, or abscesses seen on an X-ray.
In most patients who have had tooth reimplantation, over-the-counter medications like acetaminophen (Tylenol) oribuprofen (Advil) are sufficient for pain relief. Chlorhexidine (Peridex) mouth rinse may be prescribed to prevent and control gum inflammation (gingivitis), since the splinted teeth cannot be brushed normally and the splint usually collects extra dental plaque and food debris. Oral antibiotics and tetanus toxoid injections are considered for patients with accompanying significant soft tissue cuts (lacerations).
What is a displaced tooth?
Instead of being completely knocked out of the mouth, a tooth can be displaced. A displaced tooth may be pulled out and appear elongated, or be pushed in and appear shorter. A displaced tooth can also be pushed forward, backward, sideways, or rotated. While not an emergency, the sooner the dentist can splint or realign the tooth with orthodontic brackets and wires, the easier it can be brought back into proper alignment. Trauma significant enough to cause tooth displacement can also lead to pulp injury. Therefore, a displaced tooth should be evaluated periodically for several months to determine if a root canal procedure or tooth extraction is needed.
- If an area is bleeding, apply a piece of gauze to the area for about 10 minutes or until the bleeding stops.
- Apply a cold compress to the cheek or lips over the broken tooth. This will help reduce swelling and relieve pain.
MostFractureshappen when you least expect them
However, you can reduce the risk of breaking teeth by
- aiming to eliminate clenching habits during waking hours
- avoiding chewing hard objects (eg bones, pencils, ice)
- avoiding chewing hard foods such as pork crackling and dried peas etc
- wearing a Mouthgaurdwhile playing sport
- being careful with fruit seeds and pips eg olives, peaches
If you grind your teeth at night a night guard or Splintmay berecommended see Bruxism
It is very important to preserve the strength of your teeth so they are not as susceptible to fracture. Therefore have decay detected and treated early as heavily decayed and therefore heavily filled teeth are weaker than teeth that have never been filled
Individuals who have problems with tooth wear or "Cracked Tooth Syndrome" should consider wearing a night guard while sleeping. This will absorb most of the grinding forces
It depends on the direction and severity of the crack.
If the crack is small enough, it may be removed by replacing the filling.
Bonded white fillings hold the tooth together making it less likely to crack.
Sometimes the cracked part of the tooth fractures off during the removal of the filling and this can be replaced with a new filling.
The dentist may first place an orthodontic band around the tooth to keep it together. If the pain settles, the band is replaced with a filling that covers the fractured portion of tooth (or the whole biting surface). Other options include the placement of gold or porcelain fillings or even a crown.
If the crack goes too far vertically, there is a possibility the tooth may need to be removed and replaced with an artificial one. (See bridgework, denture, and implant)
The nerve may sometimes be affected so badly that it dies.
Root canal treatment will be required if the tooth is to be saved.
Front teeth usually break due to a knock, an accident or during biting.
Back teeth can also be fractured from a knock. They are much more likely than front teeth, to crack from forces applied by the jaws slamming together rapidly. This is why sportspeople wear mouthguards to cushion the blow.
Other forces occur unconsciously during sleep because people grind their teeth with a much greater force than they would ever do while awake. The first sign of problems may be what we call "cracked tooth syndrome" – a sore or sensitive tooth somewhere in the mouth that is often hard for even the dentist to find. In some individuals the grinding, called bruxism, causes tooth wear rather than fracture.
The tooth may be displaced and loose, and the gums may bleed. To prevent the loose tooth from falling out completely, the dentist can splint the loose tooth by bonding it to the adjacent teeth to help stabilize it while the underlying bone and gums heal.