Physical

An Introduction To Dentistry

by Dr.Dilan Fernando B.D.S.(SL)

There is no denying, that we live in a material world and that first impressions count. Imagine a scenario where two job applicants with the same qualifications are being interviewed. One with good oral hygiene, a pleasant smile with pearly white teeth and minty fresh breath. The other with bad oral hygiene with stained and missing teeth, with bad breath. No prizes for guessing as to who gets the job.

In this day and age outer appearance counts a lot as it sends out a message about who you are .it says you take pride in what you do, either at home or at your work place. That you are methodical and that you will work hard to achieve your goal. As dentists we treat and advice our patients to achieve this goal.

Although as dentists we treat extra- oral (head & neck) and intra- oral (teeth , gums and tissues inside the oral cavity) regions of the human body, majority of the treatments are confined to the teeth (tooth decay) and gums (gum disease).Both these conditions are preventable and treatable but early diagnosis ,treatment and understanding of the disease is absolutely vital.

DENTAL CARIES

One of the main reasons for tooth loss in adults and perhaps the main reason for tooth loss in children. Loss of teeth in adults or in children not only cause an aesthetical (appearance) problem it also Causes a functional problem when masticating (biting food) and pronouncing words. Can be easily preventable by observing good oral hygiene techniques and seeking early treatment.

CARIES AND IT’S PROGRESSION

To understand caries it is necessary to have a general idea about the tooth structure(fig 01). The tooth is made out of minerals (mainly calcium hydroxy apatite) and is considered to be the second hardest substance on earth after diamonds. It is of two main parts. The crown (the visible white part which is above the gums) and the root (non- visible part which is embedded into the jaw bones).

Crown bears the stress of mastication . It has two layers. The hard and thick outer covering is known as the ENAMEL. Underneath the enamel lies the second layer known as the DENTINE.The dentine is not as hard as the enamel and it contains small tubules called DENTINAL TUBULES that are connected to the nerves of the tooth. Next is a cavity known as the PULP CAVITY. Inside this chamber, fully encapsulated lies the blood vessels, nerves and connective tissues of the tooth.

Root fix the tooth to the jaw bone and holds it firmly in place .As in the crown this too has two layers. Outer thin layer is called the CEMENTUM. A group of very thin fibers (periodontal fibers) attaches itself to the cementum of the root and to the jaw bone, thereby fixing the tooth to the jaw bone. Underneath the cementum lies the DENTINE and as in the crown part it contains dentinal tubules that are connected to the nerves that lie inside the pulp cavity.

What is dental caries?

96% of the tooth structure is made out of various kinds of minerals. Demineralization of these minerals due to acid (mainly lactic acid) is called caries. This give rise to cavities within the tooth. Although in SRI LANKA we call this process “panuwo kanawa” ,there are of course no worms involve in this processed.

Starch containing foods that we eat are broken down to various forms of simple sugars like SUCROSE, FRUCTOSE and GLUCOSE by an enzyme which is in our saliva. Various forms of bacteria that live in our oral cavity acts on these sugars to produce lactic acid. The acid reduces the PH level of the oral cavity to around 5 and in this acidic environment the tooth structure starts to demineralize. But within 30-45 min the buffering action of the saliva brings back the PH of the oral cavity back to its original neutral level and the demineralization stops. Every time we take a meal this process occurs and therefore our teeth are vulnerable during this short period. A person who takes 3 meals a day will be exposed to total of 90-135 min (3 x 30-45 min) per day, whereas a person who eats 5 times a day (3 meals plus snacks) will be exposes to150-225 min (5x 30-45 min) per day. Therefore frequent eating is contra indicated.

ENAMEL CARIES (EARL Y STAGE )

Early stages of dental caries. The cavity itself is confined to the enamel. Since the enamel is not directly in contact with the nerves of the relevant tooth there is no pain. Therefore in most cases patients do not seek treatment. But as it gets nearer to the pulp there will be pain to stimuli such as cold, hot. Totally treatable with basic inexpensive treatment procedures.

ENAMEL AND DENTAL CARIES (MODERATE STAGE )

Both the enamel and the dentine are affected. Since the dentine is directly connected to the nerves of the tooth through the dentinal tubules, mild to moderate pain can be experienced depending on the depth of the cavity. Due to pain patients seek treatment. Can be restored quite successfully depending on the depth of cavity.

PULP EXPOSURE (GROSSLY CARIES)

Caries extend to the pulp. Blood vessels, nerves and connective tissue become non vital. To save the tooth need expensive procedures like root canal treatment and prosthetic procedures like crowns.

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