Tooth Anatomy

What Are the Different Parts of a Tooth?

Crown— The top part of the tooth, and the only part you can normally see. The shape of the crown determines the tooth's function. For example, front teeth are sharp and chisel-shaped for cutting, while molars have flat surfaces for grinding.

Gumline— Where the tooth and the gums meet. Without proper brushing and flossing, plaque and tartar can build up at the gumline, leading to gingivitis and gum disease.

Root— The part of the tooth that is embedded in bone. The root makes up about two-thirds of the tooth and holds the tooth in place.

Enamel— The outermost layer of the tooth. Enamel is the hardest, most mineralized tissue in the body — yet it can be damaged by decay if teeth are not cared for properly.

Dentin— The layer of the tooth under the enamel. If decay is able to progress its way through the enamel, it next attacks the dentin — where millions of tiny tubes lead directly to the dental pulp.

Pulp— The soft tissue found in the center of all teeth, where the nerve tissue and blood vessels are. If tooth decay reaches the pulp, you usually feel pain.

What Are the Different Types of Teeth?

Every tooth has a specific job or function (use the dental arch in this section to locate and identify each type of tooth):

Incisors— The sharp, chisel-shaped front teeth (four upper, four lower) used for cutting food.

Canines— Sometimes called cuspids, these teeth are shaped like points (cusps) and are used for tearing food.

Premolars— These teeth have two pointed cusps on their biting surface and are sometimes referred to as bicuspids. The premolars are for crushing and tearing.

Molars— Used for grinding, these teeth have several cusps on the biting surface.

Bacteria in Mouth May Cause Colon Cancer

A kind of bacteria commonly found in the mouth, which is often the culprit in gum disease, also spurs the formation of tumors in colon cancer.

Scientists had previously found that the level of Fusobacterium nucleatum in the gut was higher among people with colon cancer. That was noteworthy because fusobacteria aren’t one of the usual strains found in the healthy gut.
However up to now it hasn’t been clear whether the foreign bacteria caused tissue to turn cancerous or whether the bacteria was a result of the cancer. Now, researchers report that the bacteria in fact stimulates tumors, and they identify the molecule responsible for the bug’s harmful effects.

A Common Cancer
Colon cancer is the second-leading cause of cancer death in the United States, and more than 1 million new cases are diagnosed worldwide each year. By figuring out how fusobacteria spur cancerous tumors, scientists can work toward therapies that may inhibit the bacterium’s activity and possibly eradicate it altogether from colon tissue.  Previous studies have focused on a subset of colon cancer that is caused by inflammatory bowel disease, or conditions linked to inflammation of the colon and small intestines. The teams publishing studies today focused instead on a bacterium that drives cancerous tumors but isn’t related to apparent intestinal inflammation.

Colon Cancer and Bacteria
In the first research paper, a team from Harvard and the Dana-Farber Cancer Institute report that fusobacteria are prevalent in colon adenomas, essentially early-stage benign tumors that over time can turn malignant. Working with mice that were known to develop intestinal tumors, the team was able to accelerate early tumor formation by feeding them fusobacteria.  Researchers also fed them three other bacteria strains, such as Streptococcus, that are known to be associated with colon cancer. Tumors formed at a higher rate in mice fed with fusobacteria versus those who got Streptococcus.  Unlike the other bacteria, fusobacteria were stealthy and worked at the micro-inflammation level—the Harvard team saw no large-scale intestinal inflammation.

Molecular Culprit
A second research team from Case Western Reserve University found the specific molecule that allows such stealthy invasion: a molecule called FadA. Gene expression levels of FadA were 10 to 100 times higher in colon tissues from patients with adenomas and cancerous tumors when compared with healthy participants.  Researchers also determined how FadA worked its dangerous magic: by blocking the expression of a gene that inhibits tumor growth. Both studies are published today in Cell Host & Microbe.  “We showed that FadA is a marker that can be used for the early diagnosis of colon cancer and identified potential therapeutic targets to treat or prevent this common and debilitating disease,” says Yiping Han of Case Western Reserve University School of Dental Medicine.

discovermagazine.com

Arthritis Sufferers May Find Some Relief in Periodontal Therapy

It may seem strange how some diseases are linked, but as more and more research is done, we find those links do exist. Take rheumatoid arthritis, an autoimmune disease. 
Symptoms include pain, swollen joints and stiffness. Several studies examining the relationship between rheumatoid arthritis and periodontal disease have been made in the past ten years. Perhaps the strongest statement made by any of the studies was from Australia and reported in the Journal of Periodontology, "The results of this study provide further evidence of a significant association between periodontitis and rheumatoid arthritis." The researchers measured for periodontitis using probing depths, attachment loss, bleeding scores, plaque scores, and radiographic bone loss scores. Their measurements for rheumatoid arthritis included tender joint analysis, swollen joint analysis, and pain index, physician's global assessment on a visual analogue scale, health assessment questionnaire, levels of C - reactive protein (CRP), and erythrocyte sedimentation rate.

In both diseases, the inflammation destroys the soft and hard tissue. The inflammation is caused by the toxins from bacterial infection. Even historically, some treatments for arthritis were to pull teeth or give antibiotics to the patient to relieve their arthritic pain. Once the inflammation from their teeth was controlled, the patients got better. More recently, two studies in 2012 found that the fewer the teeth and individual had, the more severe the arthritis. Out of a normal 32 teeth, those with fewer than 20 teeth were eight times more likely to have swollen joints.

As with periodontal disease and other systemic diseases, rheumatoid arthritis is a chronic inflammatory disease. Chronic infection shows up in the blood by increased levels of CRP. One inflammatory disease that produces high levels of CRP exacerbates the other. And this is also true with arthritis. And those with rheumatoid arthritis tend to have more periodontal disease. Treating the periodontal disease often gives relief to the arthritis. And treating the arthritis with antibiotics often improves the gum disease. More studies are being conducted to ascertain more quantitative data on the association between the two diseases. The once thought of as myth, is slowly being proven as fact, that periodontal disease impacts total health.

The issue is more complex than just stating that arthritis causes periodontal disease or that periodontal disease causes arthritis. However, it is evident that there is a link. And more importantly, providing the best oral care possible and getting periodontal therapy if you have the disease, will also positively impact your arthritis and potentially reduce your pain.

Dr. Piero, a Holland, MI dentist for over thirty years, is the inventor of Dental Air Force® (http://www.dentalairforce.com). Articles published are on periodontal health related to heart disease, respiratory health, diabetes, strokes, and other systemic diseases. He is the Executive Editor for Journal of Experimental Dental Science, a contributing author to Hospital Infection Control: Clinical Guidelines and soon-to-be published book, Put Your Money Where Your Mouth Is.

1888pressrelease.com

Implant Supported Dentures

An implant-supported denture is a type of "overdenture" that is supported by and attached to implants. A regular denture rests on the gums, and is not supported by implants.

An implant-supported denture is used when a person doesn't have any teeth in the jaw, but has enough bone in the jaw to support implants. An implant-supported denture has special attachments that snap onto attachments on the implants.

Implant-supported dentures usually are made for the lower jaw because regular dentures tend to be less stable there. Usually, a regular denture made to fit an upper jaw is quite stable on its own and doesn't need the extra support offered by implants. However, you can receive an implant-supported denture in either the upper or lower jaw.

You should remove an implant-supported denture daily to clean the denture and gum area. Just as with regular dentures, you should not sleep with the implant-supported dentures at night. Some people prefer to have fixed (permanent) crown and bridgework in their mouths that can't be removed. Your dentist will consider your particular needs and preferences when suggesting fixed or removable options.

How Does It Work?

There are two types of implant-supported dentures: bar-retained and ball-retained. In both cases, the denture will be made of an acrylic base that will look like gums.  Porcelain or acrylic teeth that look like natural teeth are attached to the base. Both types of dentures need at least two implants for support.

• Bar-retained dentures — A thin metal bar that follows the curve of your jaw is attached to two to five implants that have been placed in your jawbone. Clips or other types of attachments are fitted to the bar, the denture or both. The denture fits over the bar and is securely clipped into place by the attachments. 

• Ball-retained dentures (stud-attachment dentures) — Each implant in the jawbone holds a metal attachment that fits into another attachment on the denture. In most cases, the attachments on the implants are ball-shaped ("male" attachments), and they fit into sockets ("female" attachments) on the denture. In some cases, the denture holds the male attachments and the implants hold the female ones.

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Chewing Gum Improves Concentration

Chewing a piece of sugarless gum after lunch can not only help you protect your dental health, but also help focus to avoid that afternoon slump in productivity, according to researchers at Cardiff University in Wales.

 

The study, published in the British Journal of Psychology, evaluated the concentration of 38 participants who were given a short-term audio memory test.  Half the participants were instructed to chew gum during the 30-minute test. All of them listened to a list of numbers from 1-9 being read in random order and were scored on how accurately and quickly they were able to detect a sequence of odd-even-odd numbers. Participants also completed questionnaires on their mood before and after the test.  Researchers found that participants who chewed gum had quicker reaction times and more accurate results, especially during the later part of the test.  “It’s been well established by previous research that chewing gum can benefit some areas of cognition,” said Kate Morgan, the study’s lead author.” In our study we focused on an audio task that involved short-term memory recall to see if chewing gum would improve concentration; especially in the latter stages of the task.Interestingly, participants who didn’t chew gum performed slightly better at the beginning of the task but were overtaken by the end. This suggests that chewing gum helps us focus on tasks that require continuous monitoring over a longer amount of time.”

 

According to MouthHealthy.org, the ADA’s consumer website,clinical studies have shown that chewing sugarless gum for 20 minutes following meals can help prevent tooth decay.

Chewing sugarless gum increases the flow of saliva, which washes away food and other debris, neutralizes acids produced by bacteria in the mouth and provides disease-fighting substances throughout the mouth. Increased saliva flow also carries with it more calcium and phosphate to help strengthen tooth enamel.

 

Only sugarless gums have the ADA Seal, and are sweetened by non-cavity causing sweeteners such as aspartame, xylitol, sorbitol or mannitol. Of course, chewing sugar-containing gum increases saliva flow too, but it also contains sugar, which is used by plaque bacteria to produce decay-causing acids. Further research needs to be done to determine the effects of chewing sugar-containing gum on tooth decay.

 

Don’t let chewing sugarless gum replace brushing and flossing. It’s not a substitute. The ADA still recommends brushing twice a day with fluoride toothpaste and cleaning plaque from between your teeth once a day with dental floss or other interdental cleaners.

Look for chewing gum that carries the ADA Seal. The ADA Seal is your assurance that the sugar-free chewing gum has met the ADA criteria for safety and effectiveness. You can trust that claims made on packaging and labeling for ADA-accepted products are true, because companies must verify all of the information to the ADA.

 

*Visit MouthHealthy.org to see and compare a list of sugar-free chewing gums that have the ADA Seal.*