Tooth extractions and removal

published December 5th, 2008

Dentistry for the 21st Century is about preserving as much natural tooth tissue as possible. You have been used to these structures since they erupted into your mouth, and teeth are important in maintaining the supporting bone contours, as well as providing surfaces to function with. By this I mean speech, biting and chewing. Teeth in one jaw also offer support to those in the opposing jaw, to maintain their position in the dental arch. Research has also indicated that the shape and position of your teeth also push food material over the gum tissue in a very special way, massaging and cleaning the tissue as you eat.

There are several occasions where tooth extraction is necessary, and these are decay, infection, fracture and severe crowding.

Dental decay is caused by the destruction of the outer enamel surface of the tooth structure, allowing bacteria to penetrate into the less dense dentine tooth body. As the process of decay progresses, the advancing wave of bacterial products begin to irritate, then kill the nerve tissue. Once the nerve tissue dies, depending on the bulk of the tooth remaining, it may be possible to save it by root canal treatment, or if the destruction is too great, accompanied with infection in the supporting bone tissue, removal or extraction becomes the reluctant treatment of choice. There have been many theories why dental decay begins and progresses, but it is generally accepted that the following processes occur. Decay occurs at sites where bacteria accumulate and convert sugars to acid by-products of living and reproduction. These acids dissolve the mineral components in enamel, and leave rough areas, which may be stained. These ‘early lesions’ can remineralize and ‘heal’ if recognized and you, the patient, become more motivated and efficient in your cleaning routines. As further minerals are dissolved out of the decaying area, more bacteria collect in the rough area and the lesion penetrates through into the dentine. Dentine is a living tissue. If you can imagine a tooth as follows, then you will understand of the process of decay better. The centre of the tooth is soft tissue, comprising nerve and blood supply tissue. The outer surface of the nerve tissue is similar, to you scholars, to a Medusa’s head, with millions of fine ‘hairs’ that are minute nerve ends. Each ‘hair’ runs up inside a single small tube with in the dentine. So if you can imagine the dentine as an enormous bundle of straws centred around a ball ( the nerve tissue), these hairs would run up inside each straw. Covering the outer ends of the straw tubes is the enamel which is a very hard crystalline material. This outer surface is the surface that takes all the abuse of the food we eat, fluids we drink, and trauma when we bite and chew, or get hit in the mouth during sports, brawls and accidents. The reason that our teeth do not fracture all fall apart after each knock is their unique design. The dentine is 50% water, and the tubular construction when wet with nerve fluids keeps this material flexible, and able to absorb energy. So, you may well have many fracture lines that you can see in your own teeth, but the properties of the dentine bind the whole tooth together and keep it intact and functional. The analogy that I use to my Patients is a grass leaf. When wet, it can be folded, knotted and woven. These processes can be reversed, and the leaf returned to a single leaf, usually without breakage. But once the grass leaf dries to become hay, it is fragile and brittle. If you attempted to fold, knot or weave it is this dried state, it would probably break or fracture. Nature has many other examples of this. Now once the acids and bacterial by-products gain entry into the dentine, the rate of penetration and destruction is increased by its unique ‘straw-like’ construction. Depending on where the decay area started in the tooth, and the shape of the advancing decay, structural failure of portions of the tooth, or the whole crown, can occur. Unless this stage is quickly stabilized, the nerve tissue will die, leading ultimately to infection within the supporting bone tissue.

Infection in the bone tissue is not a reason per se to remove the tooth, as many patients that we see have teeth where the nerve tissue has been removed and the tooth restored once the infection has been eliminated. This process is called root canal treatment. However, re-infection can occur if the technique in cleaning, sterilization and filling of the root system is poor, or some of the cheap, outdated techniques are used. Bacterial toxins that are left in the dentine structure of the root system can cause an area of infection to develop at the tip of the root, and this occasionally can be controlled by specialized surgical procedures to remove the root tip and the area of infection. But even this extreme measure will ultimately fail if the canal system still harbors bacterial toxins. For a more predictable result, the canal system should be opened, re-cleaned and sterilised, and then filled whilst being able to access both ends of the root system. If this fails at some time after, then I personally feel the tooth should be removed with care to preserve as much of the bone structure as possible.

Other reasons for the removal of teeth are infection, fracture and severe crowding.

Infection may not be due to decay. Impacted 8’s or the teeth more commonly know as the ‘wisdom teeth’ often try to erupt into the mouth at an abnormal angle, and so are termed as impacted. The areas at the back of your mouth are difficult to get at , at the best of times, but now, with the added complication of the partially through tooth, it becomes a real hassle. If a food fragment zips into the space between the tooth and gum tissue, this can led to a low-grade infection of the gum. When this happens, the normal tight ‘collar’ of tissue around the tooth slackens off, and more food packs into the space. This food then becomes colonised by your normal bacteria within 30 to 40 seconds. You cannot usually clean this stagnating food and bacterial heaving mass out, and the material putrefies. So quite apart from the smell, the pain and a face out by your ears forces your attendance at a Dental Clinic. The treatment, after careful assessment is usually

  1. reduce the infection, and so the swelling and pain
  2. remove the tooth

Other sources of infection may result from advanced periodontal disease. The profound loss of soft and hard supporting bone tissue will allow food stagnation deep in gum tissue pocket areas, with resultant infection and pain. On occasion, if a particular tooth has no balancing tooth surface, it will continue to erupt out of the gum tissue. If this process is allowed to continue over a long time period, the tooth can fully extrude, and its loss is due to the complete absence of supporting bone tissue.

Fracture due to trauma or due to structural weaknesses brought about by the placement of fillings or presence of decay, can necessitate removal. Trauma, from accidents or blows to the face from, for example fights and sports, can remove the tooth completely from the socket. In other situations, a fracture that is below the gum tissue surface may result in insufficient root left to act as a retainer for any form of restoration.

In some Dental Teaching Institutions, extractions are still taught as the only successful way to reduce crowding and as a preliminary to orthodontic treatment. I was taught that this was the only way to treat crowding, and I was guilty of treating my patients in this way. But this has to be set against a background of the state of the knowledge in the early 80’s when I qualified, and the age of my teachers and their training. Now, of course, we know that there are many ways to avoid the trauma of extractions on young patients, and the results obtained by facial orthopaedics are brilliant. What is still sad is that in the UK, the National Health Service advisors and so called experts still perpetuate this myth. Young people in the UK are still subjected to unnecessary and traumatic tooth removal all because of cost and lack of knowledge.

Well, so far I have chatted about why teeth have to be removed. But how do we get them out ? Teeth are held into the bone sockets by fibrous strands called the periodontal ligaments. These are attached at one end to the root surface, at the other to the bone wall. It is easy to sever these fibres by applying pressure or by the use of very fine cutting instruments.

First, the surrounding tissue needs to be made numb, and this is done by injection of local anaesthetic agents. In some areas of the jaws, the bone is thin enough to allow these anaesthetics to permeate through the bone structure, and block the nerve tissue’s ability to conduct pain messages along the fibres to your brain. In other areas, such as the lower jaw, the bone is thick, and the diffusion of the anaesthetic cannot take place. In these places, the anaesthetic has to be placed by the nerve tissue in an alternative location. The main nerve tissue path way runs down from the base of brain, down the inner aspect of the jaw bone, and then loops into a canal inside the lower jaw. The anaesthetic is placed just as the nerve loops into the canal orifice. All nerve signals are then blocked from this point down. Hence the whole of the lower side of your face goes numb with this type of injection.

Alternative forms of getting the anaesthetic into the area required are to push a very fine needle between the root and the socket wall, and place the anaesthetic around the tooth we need to treat. A relatively new method of anaesthetic administration is to place a small amount of the anaesthetic in he gum tissue close to the tooth which needs treatment. A small hole is then drilled through the dense outer bone surface, into the softer bone that forms the core of the jaw bone. The local anaesthetic solution is then injected through this access.

Once the tooth and surrounding tissue has been made numb, the periodontal fibres are cut, and the tooth removed. It should be done with great care, as it is important to preserve as much of the bone as possible. Again, traditional dentistry involved squeezing the empty socket so that the walls closed and the blood clot that is essential to healing was small and easily retained. Now, we try to keep this site open but clean, so that we maximise the body’s ability to grow new bone into the socket.

There are times when the shape of a molar tooth means that extensive bone and gum tissue would result by trying to remove it intact. In this case, the tooth may be cut into small units, and each unit removed more easily.

If the root remains are buried, then the gum tissue may need to be folded out of the way, and a small amount of bone tissue removed to allow easy visualisation of the root fragment. The remains can then be more easily removed with very fine instruments.

Wisdom teeth seem to have numerous horror stories attached with their removal. The vast majority are simple and symptomless. As with many other things in life, you only hear about the problems, the pain, and the **** dentist who did it to you. But spare a thought of the dentist faced with a decayed and fractured wisdom tooth, which caused a painful episode about 12 months earlier, and the patient attached to it decided not to seek dental help. Now the dentist is presented with an area of infection, painful to touch and difficult to get at. Not surprising then this patient probably will have a horror story to tell at a later stage, and the dentist will get the blame.

If gum tissue needs to cut and folded to one side to gain access to root fragments, stitches need to be put in to hold the tissue together to allow healing to take place in a controlled way. These need to be removed, usually 3 to 7 days later, although in certain surgical procedures, they may be left up to 15 days.

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