SYDNEY DENTAL GLOSSARY
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Cone-beam computerized tomography (CBCT) has become the gold standard maxillofacial imaging technology for diagnosis, surgical and implant-treatment planning. The key difference between CBCT and its predecessors is: traditional CT scans record data with a helical, fan-shaped beam that transmits images to detectors placed in an arc around the patient, while CBCT systems employ a cone-shaped beam with a larger, adjustable field of view (FOV). And while the traditional CT captures images in thin slices that require several rotations around the patient to yield a full picture, CBCT covers the entire volume of diverse areas of interest in a single rotation.
Features and Benefits
Faster and safer
Since CBCT captures images in a single rotation, scan time is quicker than that of traditional spiral CT systems. Plus, since radiation doses are relative to the size of the FOV selected, practitioners can reduce the amount of radiation to which patients are exposed while focusing on particular regions of interest.
Comprised of 3D cuboid structures known as voxels, the volumetric data set sent to the imaging software allows for 3D images that can be manipulated to show certain tissues, view different angles, and display varying thicknesses and depths.
Not to be limited by their own advancements, CBCT systems can be used for traditional forms of radiography, including cephalometric, panoramic and 2D imaging providing additional diagnostic tools.
Greater patient comfort and improved education
On top of the peace of mind provided by lower radiation dosages, CBCT systems are manufactured specifically with increased patient comfort in mind. This means less restrictive positioning and more open environments with plenty of space. Also, the ability to provide patients with full 3D renderings of their condition illustrates problems in a visual manner, allowing them to play a larger, more collaborative role in their own treatment.
Oral Bacteria see also Plaque
- Are the oldest living forms of life on the planet first appearing about 4 billion years ago. See Life on Earth
- Are found everywhere on earth (even inYellowstonesboiling sulphuric acid springs or in radioactive waste). They exist deep in the Earth’s crust as well as in organic matter and the live bodies of plants and animals and are responsible for the initial breakdown of the human body after death see putrefaction.
There are typically 40 million bacterial cellsin a gram of soil and a million bacterial cells in a millilitre of freshwater.
- Are single-celled microorganisms that cluster in largegroupsMany bacterial species exist simply as single cells, others associate in characteristic patterns: Neisseria form diploids (pairs), Streptococcus form chains, andStaphylococcus group together in "bunch of grapes" clusters. Bacteria can also be elongated to form filaments, for example the Actinobacteria
Bacteria often attach to surfaces and form dense aggregations called plaque,biofilmsorbacterial mats
Bacteria living in biofilms display a complex arrangement of cells and extracellular components, forming secondary structures such as microcolonies, through which there are networks of channels to enable better diffusion of nutrients. In natural environments, such as soil or the surfaces of plants, the majority of bacteria are bound to surfaces in biofilms. Biofilms are also important in medicine, as these structures are often present during chronic bacterial infections or in infections of implantedmedical devices, and bacteria protected within biofilms are much harder to kill than individual isolated bacteria
Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids. In contrast, Gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. Most bacteria have the Gram-negative cell wall produce differences in antibiotic susceptibility
- Have very different shapes and sizes Bacteria have a wide range of shapes, ranging from spheres (cocci -Greek for grain or seed) to rods (bacilli –Latin for stick) and spirals (spirella). Elongation is associated with swimming
A small number of species even have tetrahedral or cuboidal shapes. More recently, bacteria were discovered deep under the Earth's crust that grow as long rods with a star-shaped cross-section.
A few species – for exampleThiomargaritanamibiensis and Epulopisciumfishelsoni– are up to half a millimetre long and are visible to the unaided eye.
Among the smallest bacteria are members of the genus Mycoplasma, which measure only 0.3 micrometres, as small as the largestviruses.
- Can be measured in nano and micro meters(average 0.5-5 microns)
- Unlike cells of animals and other eukaryotes,bacterial cells do not contain a nucleus and rarely harbourmembrane-boundorganellesBacteria lack a cell nucleus or any othermembrane-bound organellesand are called prokaryotes and differ from the eukaryotes, which have a cell nucleus.
- Many bacteria can move using a variety of mechanisms: flagella are used for swimming through water; bacterial gliding and twitching motility move bacteria across surfaces; and changes of buoyancy allow vertical motion.Swimming bacteria frequently move near 10 body lengths per second and a few as fast as 100. This makes them at least as fast as fish, on a relative scale.
- Bacteria grow to a fixed size and then reproduce through division or binary fission, a form of asexual reproduction. Under optimal conditions,bacteria candouble every nine minutes.Eagon RG (1962). "Pseudomonas natriegens, a marine bacterium with a generation time of less than 10 minutes". Journal of Bacteriology83 (4): 736–7.
Thus one germ can become one million in seven hours under ideal conditions.
- The human body is replete with bacteria. There are ten times more bacteria than human cells - particularly in the gut and on the skin Sears CL (2005). "A dynamic partnership: celebrating our gut flora". Anaerobe11 (5): 247–51
- Some are helpful (see good bacteriaand probiotics )and others are harmful (see bad bacteria)
- The vast majority of the bacteria in the body are rendered harmless by the protective effects of theimmune system. This is natures answer to medications such as antibiotics. When bacteria counteract the immune system the result is infectious diseases.
Bacteria in plaque is mainly gram positive
Because of their ability to quickly grow and the relative ease with which they can be manipulated, bacteria are the workhorses for the fields of molecularbiology, genetics and biochemistry.
The ability of bacteria to degrade a variety of organic compounds is remarkable and has been used in waste processing and bioremediation.
Bacteria capable of digesting the hydrocarbons in petroleum are often used to clean up oilspills.Fertilizer was added to some of the beaches in Prince William Sound in an attempt to promote the growth of these naturally occurring bacteria after the infamous 1989 ExxonValdezoilspill. These efforts were effective on beaches that were not too thickly covered in oil.
Bacteria are essential to recycling of nutrients.They have the ability to break down certain organic compounds and are used in waste reprocessing, sewage treatment and bioremediation of industrial toxic waste.
In biological pest control, bacteria (egBacillus thuringiensisor BT)have often replaced pesticides especially in organic farming. Because of their specificity, these pesticides are regarded asenvironmentally friendly, with little or no effect on humans, wildlife, pollinatorsand most other beneficial insects.
One of the most important applications of bacteria in the chemical industry is in the production of pure pharmaceuticalseg insulin, growth factor and antibioticsand pure agrichemicals.
Along with yeasts and molds, lactic acidbacteria (such as Lactobacillus and Lactococcus) have been used for thousands of yearsin the preparation of fermented foods like cheese, sauerkraut, wine, soy sauce, pickles and yoghurt.The invention of bread and beer has been argued to be responsible for humanity's ability to develop technology and build civilizations.Beer,the third most popular drink after waterand teais one of the world's oldest prepared beverages, possibly dating back to the early Neolithic or 9500 BC, when cereal was first farmed. It is recorded in the written history ofancient Egypt and Mesopotamia.
Pseudomonas may be the most common nucleator of ice crystals in clouds, thereby being of utmost importance to the formation of snow and rain around the world
In the human body(See Probiotics) bacteria are an essential aid to digestion and assimilation of foods. A bacterial imbalance in the colon gives rise to several ailments of the digestive system. The ideal bacterial balance is a ratio of 85 percent probiotic (good) bacteria and 15 percent pathogenic. Probiotics also help strengthen the body’s natural immune system. Unfortunately in most people this ratio does not exist.
Probiotics-- often called "friendly" or "good" bacteria-- are live, lactic-acid producing microorganisms that are similar to those found in the human digestive tract.
- Can reproduce with lightening speed
- Release tissue damaging toxins
- Gain entry through inhalation, ingestion or a break in the skin.
Some examples of bad bacteria are:
- E. coli
Some familiar diseases caused by bad bacteria include:
- acne, anthrax
- brucellosis.Bubonic plague
- cholera, conjunctivitis ~ pink eyechlamydia
- ear infection, eye stye, enteritis
- food poisoning
- gastroenteritis, gonorrhea, gastritis
- kidney infection
- leprosy, lyme disease
- pneumonia -anotable cause of death in the elderly
- periodontal (gum) disease, peptic ulcer ~Helicobacter pylori
- Rheumatic Fever
- sinusitis, syphillis, Scarlet Fever, Strep Throat, salmonellosis, skin abscess/boil
- staph infection/MRSA(multi resistant staph aurius)
- tooth abscess, tonsillitis, tetanus, Typhiod Fever
- tuberculosis - killing about 2 million people a year, mostly in sub-Saharan Africa
- ulcerative colitis, Urinary Tract Infection(UTI)/bladder infection
- whooping cough
If bacteria form a parasitic association with other organisms, they are classed as pathogens. Pathogenic bacteria are a major cause of human death and disease and cause infections such. The most common fatal bacterial diseases are respiratory infections.
Bacterial diseases are also important in agriculture, with bacteria causing leaf spot, fire blight and wilts in plants, as well as Johne'sdisease, mastitis, salmonella and anthrax in farm animals.
Each species of pathogen has a characteristic spectrum of interactions with its human hosts. Some organisms, such asStaphylococcus or Streptococcus, can cause skin infections, pneumonia, meningitis and even overwhelming sepsis, a systemic inflammatory response producing shock, massive vasodilation and death. Yet these organisms are also part of the normal human flora and usually exist on the skin or in the nose without causing any disease at all.
Other organisms invariably cause disease in humans, such as the Rickettsia, which are obligate intracellular parasitesable to grow and reproduce only within the cells of other organisms. One species of Rickettsia causes typhus, while another causes Rocky Mountain spotted fever. Chlamydia, another phylum of obligate intracellular parasites, contains species that can cause pneumonia, or urinary tract infection and may be involved in coronary heart disease.
Finally, some species such as Pseudomonas aeruginosa, Burkholderiacenocepacia, and Mycobacterium avium areopportunistic pathogens and cause disease mainly in people suffering from immunosuppression or cystic fibrosis.
“Natural” antibiotics purported to battle bacteria are:
- ozone gas and solution ~ topical
- salt solution ~ topical
- bicarb solutions ~ topical
- hydrogen peroxide ~ topical
- colloidal silver ~ oral & topical
- wild indigo ~ oral
- active yogurt ~ oral
- tea tree oil ~ topical
- raw garlic ~ oral
Bisphosphonates are prescribed drugs used for the treatment of osteoporosis, osteitisdeformans(Paget's disease of the bone), bone metastasis(high dosage) and other conditions that feature bone fragility.
Typical drug brand names include:Actonel,Alendro, Aredia,Bondronat,Bonefos, Bonviva,Didrocal,Didronel, Fosamax,Ossmax, Pamisol,Skelid and Zometa.
Although rare, bisphosphonates have been associated with osteonecrosis of the jaw (ONJ), with the mandible twice as frequently affected as the maxilla and most cases occurring following high-dose intravenous administration used for some cancer patients. Some 60% of cases are preceded by a dental surgical procedure (that involve the bone), and it has been suggested that bisphosphonate treatment should be postponed until after any dental work to eliminate potential sites of infection (the use of antibiotics may otherwise be indicated prior to any surgery)
Bisphosphonates and Osteonecrosis of the Jaw
Bonding commonly refers to the process where a dental material is strongly adhered to tooth structure usually by a combination of micro mechanical penetration of the bonding agent and chemical interaction.
This process is usually used only for white fillings and has significant advantages:
- The tooth does not need to be drilled as much for reasons of retention eg no need for “dove tailing” resulting in smaller fillings and stronger teeth. See minimal intervention
- If done correctly an impermeable seal is achieved at the tooth restoration interface. Note though that amalgamachieves a good seal by oxidation at the interface
- Allows for thin veneers to be placed on teeth
- Allows for small brackets to be placed on teeth for orthodontic tooth movement rather than bands
A three unit porcelain fused to metal bridge
A bridge is an appliance permanently fixed in the mouth to replace missing teeth. It uses remaining teeth to support the new artificial tooth or teeth.
A bridge is made up of two crowns for the teeth on either side of the gap --these two anchoring teeth are called abutment teeth-- and a false tooth/teeth rigidly attached in betweencalled pontics. The bridge can be made fromcomposite,gold, alloys, porcelain or a combination of these materials.
An enamel-bonded bridge uses a metal or porcelain framework to which the artificial teeth are attached, and then resin bonded to supporting teeth
- A bridge is one option for the permanent replacement of missing teeth and does this byjoining or connecting existing teeth or dental implants
- Bridges are usually made of porcelain fused to metal but can be all porcelain (zirconia) or fibre reinforced resincomposite.
- Bridges are usually constructedoutside the mouth however, they can also be fabricated directly in the mouth usingcomposite resin.
- Bridges involve the reduction in size of the adjacent teeth (calledabutments) using a drill so as to provide the ideal room or space for the material selected. The replacement tooth is called the pontic.
- Bruxism is the grinding and clenching of teeth
- Bruxism is not part of normal function and is called a parafunction
- Most people have done it sometime in their life
- Children sometimes grind while asleep sometimes in response to a cold or other infection and are more likely to develop it if their parents are bruxers
- Most people who brux do not know they do it and may even deny it even though signs and symptoms are present
- Factors involved in grinding include:
- Stress and tension is by far the major factor
- Stressful situations such as deaths, illness,divorse, moving house, changing jobs and examsetc will often start a major cycle of grinding
People work out their frustrations by working their jaw while asleep, perhaps in response to dreaming or in an attempt to model a conversation held earlier in the day. In fact, people who tend to talk in their sleep may be more prone to grind their teeth as well
Some studies show that persons whose personalities may be described as compulsive, controlling,precise, or aggressive (type A) may grind more. At SAS Dental we have noted a higher incidence of nail biting and other oral habits in these personality types. In addition to tooth wear and destruction a type A personality may also be expected to wear out their shoes and break toys etc more than their type B sibling.
Suppressed anger may be a factor
One theory likens tooth grinding to sharpening weapons for next days battles.
Another theory relates to Freud’s Oral FixationStage.
No one really knows exactly why just that stress is an important factor
- Having an abnormal bite or malocclusion such as crooked or missing teeth or even an active cavity or abscess
- Certain sleepdisorders
- Consumingexcess sugar, alcoholor caffeine before sleep can encourage random muscle activity and worsen the bruxism
- Illicit stimulant drugs
- Taking certain medicationsmay worsen the bruxism. Selective serotonin reuptake inhibitors (SSRIs) taken for depression may also lead to involuntary movementssince they stimulate the central nervous system
- Certain medicalconditionsincluding sleep apnea and the involuntary movements of Parkinson’s disease may also contribute to this condition.
- People who sleep on their stomach or side are more inclined to grind teeth than back sleepers. So, simply changing positions or even moving to the other side of the mattress may help
- The results of bruxism include:
- Severe attrition(wear) of the teeth (see Case Study M03). Often the upper front and lower back teeth are most effected.
- Enamel cracks, toothfracturesand loss of fillings
- Damage to the jaw joints and muscleswith severe pain or dysfunction in the temporomandibularjoints(TMD) and Myofacial Pain Disorder (MPD)
- Frequent muscle tensionheadaches
- Earaches, tinnitus (ringing) and even hearing loss
- Excessive muscle contraction forces as the closing muscles of the jaw shorten (which can accelerate the destruction)
- Swollen or hypertrophied masseter muscles giving the appearance of enlarged jaws
- Bone loss
- Tooth sensitivity to hot, cold and sweet
- Tooth loss
- Ridging on tongue and cheek – sometimes biting
- Aggravation of periodontal disease if present ("secondary occlusal trauma")
- Shortening of the lower face height or loss of vertical dimension or collapse of the bite (which can change one's appearance – corners of the mouth sag)
- An inverted or reverse smile
- A "toothless"
- Frequent cracking or chapping at corners of the mouth ("angular cheilitis") and
- Problems chewing.
- May contribute to insomnia
- Grinding not very pleasant for partners – may disturb their sleep
- Treatment focuses on:
- Improving conscious awareness
- Attending to the cause if known
- Stress reduction and anxiety management strategies such as various relaxation techniques, exercise, meditation, yoga,cognitive behavioraltherapy, psychotherapy, hypnotherapy, warm baths, aromatherapy, meditation, biofeedback, affirmations and visualisation are sometimes recommended
- Massaging and stretching the muscles of the shoulders, neck, face and jaws including the ptyerygoid muscles intra orally may also help.
- Applying ice or wet heat to sore jaw muscles
- Supplements of B group vitamins (especially Pantothenic acid B5 found in meat, eggs, legumes, whole grains and milk) and magnesium may be helpful
- In terms of diet:
- avoid eating hard or tough foods
- avoid eating late in the day (after 6 pm)
- avoid alcohol and caffeine late at nightand
- drink plenty of water
- Good quantity (minimum 8 hours)and quality (comfort and position) of sleep
- Usually an occlusal splintor night guard is recommended
- Also, Botox injections into the muscles involved have shown promise
- Although sedatives and muscle relaxants can help with diagnosis and with very severe episodes they are never recommended for definitive treatment