The oral cavity is one of the many systems that is perfectly designed while a fetus develops in a mother’s womb

The first event that takes place inside the mother’s womb is the union of sperm and egg to form into a single cell which later takes the shape of an embryo by rapid division and development. This embryological development occurs in three stages.

In the first of these stages (2-5 weeks), the fertilized egg (zygote) proliferates by dividing and planting itself to the womb wall (implantation). During the advance of the zygote towards the womb, some biochemical signals are sent in order to make the mother sense this situation. Via these signals, the mother’s body is prepared to supply the necessary nutrients to this cellular mass. When these biochemical signals reach the ovaries, various hormones are secreted and the ovulation that occurs during monthly periods is ceased.

During the second stage (5-6 weeks), major activities are started inside the cellular mass, which is now in the form of an embryo. The developmental process of organ and system generation from cells begins.

And during the third stage (from the 8^th week until birth), the embryo has become a fetus, and its facial and bodily structures have begun to be immaculately shaped (Figure-1).

How do organs develop?

Tissues and organs of the embryo, which morphologically starts to look like a human, develop from three layers, which are called the ectoderm, mesoderm, and endoderm. While the baby continues to come to life inside the mother’s womb, the cranial and facial regions, along with oral cavity, start to form via the development of cells in the area called the neural crest. This development is the result of perfectly corresponding functions in between the epithelium and outer mesenchyme, which results in the facial skeleton and formation of teeth.

Jaw and facial development occur during the 4-12 weeks in the womb. By the end of the 10^th week, the face can be seen with an ultrasonographic examination.

The nose forms at this point. Mid and lateral nose projections develop. A forehead projection called the “frontonasal protrusion” forms in between the two sided mid nose projections. These projections initially develop towards the lower direction because of the volume of the tongue. Later, after the palate has begun to form, and with the growth of the lower jaw and the downward extension of the tongue, like an open-close bridge, the lower and upper jaw join at the midline by rising upward. This union takes place from front to back, like closing a zipper, stage by stage.

This way, the oral cavity and the surrounding structures (tongue, teeth, etc.) that will enable speech and taste are knit, loop by loop, inside the mother’s womb. (Figure 1-2)

Due to the complexity of this process, if there happens to be any failure in the merging, some anomalies can form, such as split lips or palates. These splits are anomalies present at birth. Such lip or palate splits may arise during this phase of the pregnancy because of various negative factors: they can stem from inter-family marriages, diseases that the mother experiences during the first three months of the pregnancy (especially measles or toxoplasmosis), exposure to radiation, alcohol consumption during pregnancy, or various drugs the mother uses. These anomalies need to be corrected by plastic surgeons, upper respiratory tract specialists, and orthodontists.

Despite these anomalies, most of the time, babies are born with their oral cavities in perfect working order – which is extraordinary given the complexity of the process.

Reference

Oral R. J, Goldman H.M. Thoma’s oral Pathology.The CV Mosby Comp. St. Louis.

Figure-1: Ultrasonographic image of the facial region of a fetus in the mothers womb.

Figure-2: Upper jaw bone

In the past, the area missing a tooth could be filled by bridge implants by eroding the enamel on neighboring teeth. In cases where there was a large gap or no teeth to use as connectors, removable implants were used. In other words, present healthy teeth would be treated to compensate for the missing teeth; if the number and health of the remaining teeth was not sufficient, removable implants would be produced that gave the “ready to fall out” feeling. The imperfections of this type of implant led scientists to pursue new ideas.

Scientists have tried to fill in missing teeth with artificial roots and with implants mounted over these by mimicking the existing tooth root. This way, there is no need to treat and erode the healthy enamel of neighboring teeth in the gap. These artificial roots, which are positioned into the jaw bone by a surgical operation, are called a “tooth implant.” Modern-day implants are generally composed of two main parts.

One of these is the fixture part which is secured into the jaw bone by screws; the other is the support part (abutment) which mimics the visible parts of the tooth in the mouth. Approximately 3-4 months of curing time is required for the fusion of bone and implant (osseointegration), which is screwed together by a surgical operation. Towards the end of this time, the implant is built over the abutment. The length of time necessary for the implant to integrate with the bone to replace a tooth which can be extracted so quickly is rather noteworthy despite ongoing studies to reduce the wait time and successful attempts to do so.

Employed materials

Even though the main logic for implants is the mimicry of the tooth and the root, the materials utilized are quite variable. The history of such implants goes back thousands of years. The employment of bamboo sticks in tooth restorations could be seen in some civilizations, such as ancient China. Mayans used sea shells, which were recently shown to be biologically suitable as implant material. Maggiolo produced a tooth root by using gold, in 1809. In the beginning of the 20th century, Lambotte prepared implants using materials such as aluminum, silver, brass, copper, and gold.

These newer implant methods have failed because of the insufficient strength of the majority of the materials and the failure to fit into biological tissues. The initial employment of titanium and its alloys in the 1950’s almost opened a new age in implantology and enabled the successful use of these materials up until today. However, these titanium implants, which are considered successful, have a very limited ability to mimic tooth roots:

• Once the implant is in place, for reasons such as aging and improper tooth brushing, tooth gum recession and resurfacing of the bright faces of the implants which mimic the root surface can take place. This leads to undesirable displays. Even though gum recession can also occur in natural teeth for similar reasons, this situation is not as disturbing as with implants. This is because the tooth root color is similar to that of the tooth surface.
• Under normal conditions, implants should be fused to integrate with the bone (osseointegration). Integrated implants are considered successful clinically. A similar case to this bondage, which is unwanted clinically, is the fusing of tooth and bone which can be seen generally in dead teeth and is called ankylosis. Many hardships can be encountered when the tooth that is fused with the jaw bone is required to be removed. The same thing also applies to the implant. If an implant is set to be extracted for a reason, even if just a small amount must be removed, the surrounding jaw bone must be removed as well. However, a natural tooth is not bonded so tightly to the jaw bone, as if the tooth is healthy, it is suspended over the jaw bone through small suspension-like structures. When a tooth is needed to be pulled as a result of trauma or tooth rotting, only these suspensions are detached; thus any damage to the jaw bone is averted. Present efforts to design similar mechanisms for implants have not been successful yet.
• When a disease develops in our natural teeth, we feel pain and take action before it is too late. However, diseases within implants are rarely encountered as pain; generally, when the pain is felt, the implant is already disconnected from the bone and it is lost. Toothache often felt as a strong pain is a blessing granted to us. If the implants were built with pain mechanisms, just like in our natural teeth, we could take action at the beginning of the disease and avoid the time and financial losses.
• Even a healthy tooth, which we think of as immobile, can move via microscopic ligaments for 0.1 mm around its root on a type of pad. The tooth root is created in a perfect fashion to resist the strong chewing power that can be generated from many directions in the mouth through these ligaments, which are wrapped around different sides and which come from different angles. However, these ligaments, which act as a suspension, do not exist in between the implant and jaw bone. Therefore, implants are almost immobile. Even though it may seem like a good thing for them to be immobile and tightly fixed, there may be intense power spots generated on the implant or jaw bone since these forces acting on the implants are transmitted to the jaw bone without being dispersed. Forces densely acting on small areas can lead to fractures of the material, including tiny screws or porcelain plating, and can damage the bone tissue. Investigators once understood that these tiny, suspension-like structures won’t form around the implant, so they engaged in mounting tiny Teflon or spring pieces inside the implant to generate suspension. However, these imitated suspensions failed to resist the chewing forces that can go up to 400 kg at times, and their use was aborted after a short time.
• Teeth can be examined by the method of tapping with small hand tools (percussion). These small impacts cause pain in case of an abscess at the tooth root. By taking necessary actions, the tooth can survive longer. It is impossible to do such determination and diagnosis with implants.

As it is seen, making less successful artificial implants as opposed to real teeth is quite a cumbersome, costly, painful, and time consuming job. Despite all of these imperfections, because of their numerous advantages over traditional implants, the popularity of dental implants continues to increase, and is preferred by dentists and patients. In addition, implants are seen as an inevitable treatment option when tooth loss occurs, and may ultimately provide patient relief in the long run.

Despite progress made in implants, it’s clear that our teeth were created in such a perfect way, down to the very smallest detail, that they cannot be replaced. Science is well aware of the fact that we will never fully be able to replicate tooth structure. Therefore, studies are shifting towards stem cell research. This way, instead of foreign substances, the missing tooth will be compensated as if by planting tooth seeds by using human’s own cells. Nonetheless, the opportunities that are discovered via all these efforts will never replace the natural teeth that were so perfectly created for us.

A tooth is created with four main layers: enamel, dentine, pulp chamber and cementum (the thin layer where the tooth attaches to the jaw). The hardest tissue of the body, the enamel is the protective, outermost layer of the tooth. Since it does not contain any living matter such as veins or nerves, we are not affected by hot, cold, sweet or sour stimulants via the tooth. If the Owner of an Everlasting Might and Compassion had not created the enamel of the tooth, which He placed at the entrance of the digestion room in the human palace, as he did, the variety of food we would eat would be very limited. Even slight contact with air would cause us great discomfort, and speaking or even opening our mouth would give us great pain.

The dentine, the hard layer just below the enamel, is a tissue sensitive to hot, cold, sweet and sour stimulants. As a reflection of the Creator’s Affection for His Creation, the dentine tissue is repaired when necessary by the restoring cells that he placed there.

The most inner part of the tooth is the organic part called the pulp chamber, which is filled with veins to protect the tooth from decay and feed it with necessary nutrients. Nerve cells in the soft pulp tissue play the greatest role in sensing the stimulants of heat, cold and pressure.

If we examine the anatomical structure of a tooth in detail, only then can we clearly see how it is perfectly equipped with wondrous and intelligent structures. However, are we really conscious of the duties of our teeth, placed in our jaws like pearls, in protecting our general health?

One of the main entrances to our bodies for microbes is the mouth. Because of this, maintaining healthy teeth and a clean mouth is very important in preventing diseases and maintaining a healthy life. When the mouth is not kept hygienic, a suitable environment is formed for the emergence of even very feeble microbes. In an unhygienic mouth, food residue accumulates and forms a bacterial plaque on the teeth. Using the glucose in this plaque, these bacteria produce acids. It is this acid that causes tooth decay and gum diseases.

Are we adequately informed about dental health and hygiene, a very important concept in preventive medicine? That Prophet Muhammad, peace and blessings be upon him, emphasized the importance of cleaning the mouth and teeth whenever one does his/her ablution and after every meal, grants a profundity of worship to God by keeping our teeth healthy.

Importance of Milk Teeth

Milk teeth start to appear in a baby’s gums after about the sixth month of age. The appearance of milk teeth differs from baby to baby according to factors like genetics, birth weight, socio-economics and nourishment level. By cutting a group of teeth every six months, all of the milk teeth appear by the age of 30 months. Between the 6th and 12th months the first incisors, between the 12th and 18th months the first molars, between the 18th and 24th months the first canines and between the 24th and 30th months the second molars erupt. Since the dentine tissue is not fully developed in this period, milk teeth are not at all resistant to decay. Since the pulp chamber is very soft and packed with blood vessels, it is very vulnerable to decay. Sucking fingers, excessive use of a pacifier, sucking or biting lips and gritting teeth all negatively affect the development of milk teeth. During the eruption of milk teeth, babies may have discomfort like itching gums, a need to bite something, excessive saliva secretion, watery eyes, lack of appetite, loss of weight, fever, bad temper and crying. In order to relieve these discomforts, the baby may be given something to chew on to relieve the pressure on the gums, and some cold drinks and cold food to soothe the pain.

As nothing in creation occurs devoid of wisdom, one may ask “What benefits are there after the discomforts when a baby’s milk teeth are coming in?” In other words, why are the milk teeth so important? Most of us do not give them enough care, because we think of them as temporary. The space occupied by the milk teeth is saved for the permanent teeth, and when the permanent tooth starts erupting, the milk tooth guides it into its proper place. If milk teeth are extracted too early, this alignment and spacing function of milk teeth cannot be performed, hence the permanent teeth may erupt in an improper way. Moreover, milk teeth provide proper chewing and correct vocal speech for the baby. When a baby develops unhealthy milk teeth, this may cause problems like poor facial appearance, and therefore some psychological disorders in the future. Untreated defects of milk teeth can cause pain, bad breath, difficulty in chewing, disorders in jaw development, malnutrition, aesthetic and general health problems like rheumatism and heart diseases.

Protection of Milk Teeth

Since tooth decay in babies’ teeth is very difficult to treat, preventive measures are much more important in looking after the milk teeth. Some of these measures are as follows;

• A baby must not allowed to sleep with A milk bottle in her/his mouth,

• Sugar, honey or any other sugary substance must never be added to baby’s milk,

• Baby must be given water after every feeding,

• After baby’s first teeth erupt, after every morning and evening meal, his teeth must be wiped with a soft, wet, clean towel,

• Give a soft learning toothbrush to the baby to play with.

A child must start using a toothbrush after his molars erupt, at the age of 2.5 to 3 years old. The size of the toothbrush should be suitable to the child’s mouth. It should be soft and made of nylon. Children can only brush the front of their teeth. Since the space between the teeth should also be cleaned to provide a shield against decay, parents should supervise their children when brushing their teeth. At this age, a child cannot brush his/her teeth properly, but the main aim to be achieved is for him/her to get into the habit of brushing teeth. Toothpaste may start to be used for the child after the age of three. We must not forget that the important thing for oral hygiene is not the toothpaste itself, but brushing the teeth properly and thoroughly. If these measures are not taken, or if it is already too late, any disorder in the milk teeth must be treated immediately without making the mistake of thinking the milk teeth will be replaced anyway.

Permanent Teeth

The first permanent teeth are the first big molars, which erupt when the child is about six years old. Between ages 7 and 9, the lower and upper incisors, between ages 9 and 10, the lower canines, between 10 and 12, the first and second small molars, between 11 and 12, the upper canines, between 12 and 13, the second big molars, and finally, between 17 and 21, the wisdom teeth, the third molars erupt. During the eruption of permanent teeth, some problems like distorted development may occur. Genetic factors, early loss of milk teeth, breathing disorders, untreated cavities between milk teeth and a mismatch of jaw and tooth sizes, may cause irregular development of teeth. The dental treatment practiced for aligning such irregular teeth is called ‘orthodontic treatment.’ Since irregularities of teeth form spaces suitable for the accumulation of food residue which allows microorganisms to increase and then leads to decay, orthodontic treatment should be done before the permanent teeth are firmly positioned. Irregular teeth may cause jaw-aches because of abnormal interlacing of upper and lower teeth.

There are different thoughts about whether the wisdom teeth should be pulled out or not. Wisdom teeth are placed at the furthest back part of the jaw curvature. This part of the mouth is very suitable for food residue and microorganisms to accumulate. Because of this, wisdom teeth are very vulnerable to decay. In addition, any decay in these teeth may also affect the adjacent molars. If a positive result will not be achieved from treatment, these teeth can then be pulled out. However, if the wisdom teeth will erupt correctly into their places and do not negatively affect the surrounding tissues, and if there is sufficient space for them in the jaws, it is definitely beneficial for them to stay.

Another tooth problem that seems to concern today’s aesthetic conscious individuals is the color of teeth. However, tooth color is completely a personal phenomenon, like eye or skin color. But still, we must know that some external factors, like tea, coffee, smoking, feeding habits and tooth injuries, and some internal factors, like genetic attributes and aging, may also affect the color of the teeth.

What should we do to obtain Dental Health?

Mouth and tooth hygiene is an important issue that was emphasized strongly by Prophet Muhammad, peace and blessings be upon him, and the most effective method he used was brushing the teeth. However, after eating acidic foods or drinking acidic drinks like fruit juice, fruits, soft drinks or fizzy drinks, you should wait for about 30 minutes, because the dental enamel will be softer and more sensitive just after consuming such foods and drinks and if you brush straightaway, you may rub the acid into the enamel tissue of your teeth. You can clean the residues of acidic foods and drinks by rinsing your mouth with water or a fluoride based mouth rinse.

Having a healthy mouth and teeth mainly depends upon applying a good brushing technique to the teeth and gums. By applying the brush in a circular manner, you should always start brushing the gums towards the teeth, then the outer surfaces and finish with all inner surfaces. You must avoid damaging the masticator surfaces by applying too much force. Brushing the teeth twice a day at least is necessary to prevent the formation of bacterium plaque.

In order to achieve ideal hygiene for your teeth, you should also use dental floss for cleaning between the teeth. This will help to clean places where a brush cannot reach and thus prevent dental plaque. Also, special mouth rinses may be used in order to provide an effective general cleanliness.

Toothpicks can also be used between the teeth. While they are cheaper, they cannot provide a hygiene as comprehensive as dental floss, since they are thicker than floss. When using toothpicks, you should choose those with blunted tips to prevent any inflammation of the gums. Food residue that has stayed too long between the teeth should not be swallowed, since large amount of harmful microorganisms may grow on it.

In elderly people, due to a lack of sufficient calcium, disorders like gum retraction and wobbly teeth may occur. For people who have lost their teeth completely, because of osteolysis of the lower jaw, dental prostheses may not fit properly in the jaw. During this time of life, extra calcium intake should be provided by following a calcium-rich diet.

With age, the amount of calcium also decreases in the body. In relation to this situation, teeth also become more fragile. Using the teeth to break open nuts may cause cracks that cannot be seen with the eye, which may later cause fractures in the teeth. Therefore, we must never use our teeth to break hard foods, such as nuts, at any age, and we must be careful about breaking teeth, especially during old age.