• Unlike cells of animals and other eukaryotes,bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Bacteria lack a cell nucleus or any other membrane-bound organelles and 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 can double 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 bacteria and 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 the immune 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.

Good Bacteria

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 molecular biology, 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 Exxon Valdez oil spill. 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 (e.g. Bacillus thuringiensis or BT)have often replaced pesticides especially in organic farming. Because of their specificity, these pesticides are regarded as environmentally friendly, with little or no effect on humans, wildlife, pollinators and most other beneficial insects.

One of the most important applications of bacteria in the chemical industry is in the production of pure pharmaceuticals e.g. insulin, growth factor and antibiotics and pure agrichemicals.

Along with yeasts and molds, lactic acid bacteria (such as Lactobacillus and Lactococcus) have been used for thousands of years in 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 water and teas, is 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 of ancient 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.

Bad bacteria:

• Can reproduce with lightning speed.
• Release tissue damaging toxins.
• Gain entry through inhalation, ingestion or a break in the skin.

Some examples of bad bacteria are:

• E. coli
• Listeriosis
• Salmonella
• Gonococcus
• Streptococcus
• Staphylococcus

Some familiar diseases caused by bad bacteria include:

• Acne, Anthrax
• Brucellosis, Bubonic plague
• Cholera, Conjunctivitis ~ pink eye chlamydia
• Diphtheria
• Ear infection, Eye Stye, Enteritis
• Food Poisoning
• Gastroenteritis,Gonorrhea, Gastritis
• Impetigo
• Kidney infection
• Leprosy, Lyme Disease
• Meningitis
• Pneumonia-a notable cause of death in the elderly
• Periodontal (gum) disease, Peptic ulcer ~Helicobacter Pylori
• Rheumatic Fever
• Sinusitis, Syphilis, 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
• Vaginosis
• 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's Disease, mastitis, salmonella and anthrax in farm animals.

Each species of pathogen has a characteristic spectrum of interactions with its human hosts. Some organisms, such as Staphylococcus 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 parasites able 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, Burkholderia Cenocepacia, and Mycobacterium avium are opportunistic 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
• Bicarbonate solutions ~ topical
• Hydrogen peroxide ~ topical
• Colloidal silver ~ oral & topical
• Wild indigo ~ oral
• Active yogurt ~ oral
• Tea tree oil ~ topical
• Raw garlic ~ oral

BISPHOSPHONATES

Bisphosphonates are prescribed drugs used for the treatment of osteoporosis, osteitis deformans(Paget's disease of the bone), bone metastasis(high dosage) and other conditions that feature bone fragility.

Typical drug brand names include:Actonel, Alendronate, 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)

Further information:

Bisphosphonates and Osteonecrosis of the Jaw

BONDING

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 e.g. 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 amalgam achieves 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.

Bridges



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 between called pontic(s). The bridge can be made from composite,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 by joining 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 resin composite.
• Bridges are usually constructed outside the mouth, however, they can also be fabricated directly in the mouth using composite resin.
• Bridges involve the reduction in size of the adjacent teeth (called abutment) using a drill so as to provide the ideal room or space for the material selected. The replacement tooth is called the pontic.

Bruxism


• 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 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, divorce, moving house, changing jobs and exams, etc. 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 Fixation Stage. No one really knows exactly why that stress is an important factor. Causes are:
• Having an abnormal bite or malocclusion such as crooked or missing teeth or even an active cavity or abscess.
• Certain sleep disorders.
• Consuming excess sugar, alcohol or caffeine before sleep can encourage random muscle activity and worsen the bruxism.
• Illicit stimulant drugs.
• Taking certain medications may worsen the bruxism. Selective serotonin reuptake inhibitors (SSRIs) taken for depression may also lead to involuntary movements since they stimulate the central nervous system.
• Certain medical conditions including 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, tooth fractures and loss of fillings.
• Damage to the jaw joints and muscles with severe pain or dysfunction in the temporomandibular joint(TMD) and Myofacial Pain Disorder (MPD).
• Frequent muscle tension headaches.
• 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" smile.
• 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 behavioural therapy, 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 night and
  • 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.

http://www.articlesbase.com/health-articles/why-do-people-grind-their-teeth-at-night-3629357.html#ixzz18YFzFN7q