Complications of Dental Implants in Singapore

What's a complication?

This morning, a doctor friend contacted me about a complication with her dental implant done by her dentist, who is also a mutual friend. Yes, Singapore is a small country and everybody knows everybody, especially if you grew up here. Then it dawned on me that I actually do not have a blog post on dental implant complications even though it is a topic that I have lectured on extensively in local and overseas conferences. In scientific meetings, complications are presented from the dentists' perspective. Here in this post, I shall present it in the patient's perspective. Dental implants in Singapore are gaining in popularity and with that more complications will surface. So, what is a complication? In a nutshell, it is an unwanted outcome that usually does not happen but can happen. Things like transient post-operative pain and swelling are NOT complications. These are the sequelae of surgery which WILL happen to vary degrees, regardless of how good your surgeon is. Only when they persist beyond the expected period will they be deemed as complications. What are the complications of dental implants that are frequently encountered?

Dental implant treatment typically involve two stages. The first stage is the surgical insertion of the implant into the jaw bone. The second stage is the attachment of the prosthetic crown onto the implant. Complications can happen in both stages and they result in failure or less than ideal result of the treatment. I'll classify complications in the following way:

1. My implant is loose...

Assuming that the crown has already been placed and after using it for some time, you find that the implant tooth moves when you bite on it or when you shake it with your fingers, there can be three possible causes. We assess this situation from a top down approach. First we check out the crown. The crown is attached to the implant by one of two methods.

a. It is cemented to a post called an abutment which is in turn screwed usingtment screw onto the implant using an abutment screw (cement-retained) or

b. built together with the abutment and screwed onto the implant in one piece using an abutment screw (screw-retained)

If the implant tooth is loose due to the loosening of the abutment screw, then tightening of the abutment screw with a torque wrench will solve the problem. For cement-retained crowns, removal of the crown to tighten the screw may result in having to redo the crown. 

If the abutment screw is not loose, the looseness of your implant tooth is due to the implant itself ie the titanium screw that is in the bone. This can be either a biological or mechanical failure. The bond between the implant and the bone is a biological bond whereby the bone cells stick directly onto the implant surface. If this bond is disturbed and the bone cells does not bond directly to the implant, the implant tooth will be loose. This can be caused by infection or overloading of the tooth. Treatment for this is to remove the implant as soon as possible to allow the infection to clear and the bone to heal. Once the bone heals, a new implant can be placed to replace the failed implant. 

The other cause of a loose implant is that the implant itself fractures. Dental implants are designed in such a way that the top part of the implant is hollowed out to accomodate the abutment screw. As such, overloading of the implant coupled with loss of bone support around the hollowed part of the implant can result in fracturing of the implant. If this happens, the broken top part of the implant can be removed easily together with the crown but the lower part of the implant that is still integrated with the bone will need to be surgically trephined out. Similarly, after healing of the wound, a new implant can be placed.

2. My implant is painful...

An implant that is integrated will not be painful. Unlike a natural tooth, implants have no nerves and do not give "toothache" per se. However, if the implant is infected, the infection of the bone and soft tissue around it can give rise to pain. This is not the same as the post-operative pain that you get in the first few days after surgery. Clinically, there are usually signs of inflammation or infection like swelling, discharge, redness, etc in addition to the pain. Dental x-rays may also show a band of shadow along the periphery of the implant indicating resorption of the bone. Infection usually start from the gum area and spread down to the bone, just like in natural teeth having gum disease. Some soft tissue inflammation may be due to some of the cement that is use to cement the crown getting stuck in the gum. Removal of the cement will usually resolve the pain. Others may involve the bone which will also manifest as the implant becoming loose. In such cases, the implant may have to be removed as described above.

3. My implant is ugly...

When I first started doing implants more than twenty years ago, implant teeth don't really look like teeth, they are only designed to function like teeth, to restore masticatory function to the patient who otherwise cannot chew. Today, advances in technology has enable the fabrication of implant crowns to look almost exactly like a natural tooth. Aesthetics is a major consideration in implant dentistry especially when replacing front teeth. Aesthetic complications can be traced back to both the surgery and the prosthetic phase of treatment. Some aesthetic challenges arises from the initial placement of the implant. If the implant is not placed optimally, the "natural-ness" or aesthetics of the final crown will be limited. It's like having a tooth that is malaligned or twisted. This can  happen because of the lack of bone in the ideal position of the implant resulting in the implant being placed slightly off. This is a matter a just one or two millimeters and the result of the final crown can be vastly different. This is a difficult complication to fix as an integrated implant cannot be easily removed. If removal is straightforward, the implant can be removed, the ideal site bone grafted and then re-implanted at a later time. However, if the implant cannot be removed without signficant morbidity, then some camouflage work can be done by modifying the hard and soft tissue around the implant and redesigning the crown.

In cases where the implant is optimally placed and the crown is still ugly, then all that is needed is for your dentist to remove the crown and make a new one, perhaps using a different techician.

4. My implant traps food...

This is a common complaint amongst implant patients. It is a relatively minor problem as it does not affect function or aesthetics but is mainly an irritation. Why this happens is because implants are usually placed at a time when the socket of the extracted tooth has already healed. This part of the jaw bone usually shrinks as it heals and that results in the implant being placed into a part of the jaw that is slightly contoured inwards compare with the adjacent bone where natural teeth are present. This difference in contour often results in food getting trap. This can be mitigated by contouring the crown to minimize the concavities. Alternatively, the shrunken area can be rebuilt with bone and gum grafting procedures.

5: My lips are numb....

If your lower lip is still numb after the local anesthesia has worn off, it is because the implant may be placed too close to a nerve. There is a nerve that runs within the lower jaw bone, entering the bone at the back and exiting near the premolars to innervate the lips and the chin area. Implants placed in the back (from premolars onwards), runs a risk of affecting this nerve which then result in numbness. To minimize the risk of this, accurate imaging techniques such as CT scans can be use preoperatively to assess the position of the nerve so that the implants can be planned in such a way to avoid it. However, if you have already done the implant and are feeling numb in the lower lip beyond the initial days, then there may be some damage done already. You should go back to the surgeon who placed your implants for a thorough assessment. A postoperative CT scan will show whether the implant is indeed close to the nerve. If so, your surgeon may decide to remove the implant to relieve the impingement on the nerve. The recovery of sensation is tracked over the next six months. If the degree of numbness is very profound, nerve repair surgery may be indicated. Fortunately, such cases are rare and the majority of patients with nerve injury due to dental implants usually recovered to an extent where the numbness is not disruptive to their normal routine.

Do your research...

The above list is by no means exhaustive, as to do that will require a long lecture. Dental implants in trained hands are very safe and predictable. There may be minor hitches along the way but the long term benefits of dental implants outweigh their initial incoveniences. Do you research, look for a dentist who is has the necessary skills and experience to suit your needs and you can avoid many of the complications that may come with implant dentistry.