While modern implant dentistry has a high success rate of 90-95 percent, like all surgical procedures, there are some risks involved with dental implant treatment.
It is important for the implant dentist to understand the various dental implant problems that can occur .With a good understanding of such complications, the implant dentist can reduce the number of dental problems that can occur. On the other hand , it is also pertinent for patients to know that while the risk of dental implant procedures are low , certain dental implant complications can be encountered.
What are the common dental implant problems ?
As dental implant procedures involve a number of intricate steps , some of the more common dental implant complications that can occur are as follows.
1. Nerve Injury
Lower dental nerve – marked by the green line
This is usually associated with placing dental implants in the premolar and molar area of the lower jaw . As shown on the xray on the left , the lower dental nerve runs through the lower part of the lower jaw just below the root apices of the lower molars and premolars. Any injury to the lower dental nerve will result in numbness or parasthesia of the lower lip , tongue ,or teeth. These symptoms can be temporary or permanent depending on the extent of the injury.
However, in the hands of a skilled experienced implant dentist and with the the aid of Cone-beam CT Scan , the incidence of nerve injury is extremely remote.
The xray on the left shows an implant fixture that is too long . As a result of the impingement of the lower dental nerve ( marked in green ) by the dental implant, the patient experiences numbness of the lower lip. In this case, the patient should inform the implant dentist as soon as possible, as quick removable of the implant fixture will minimize the risk of permanent nerve injury. A preoperative cone beam CT Scan will definitely reduce this dental problem tremendously as it enables the implant dentist to measure exactly the amount of jaw bone above the lower dental nerve.
The use of drill stops is another useful preventive measure as it prevents over preparation of the implant site.
2. Nerve Injury
Sinus floor on the back of the upper Jaw – marked by the red line
This dental implant problem is usually associated with placing implants at the back of the upper jaw.
Placing dental implants at the back of the upper jaw is a bit more technique sensitive due to the proximity of the sinus cavity. Perforation of the sinus floor and introduction of foreign bodies is a common cause of sinusitis (infection of the sinus). Common symptoms of sinusitis are blocked or congested nose, throbbing headache, sinus discharge or fever.
Detailed pre-op 3-D Conebeam Ct Scan is a key to preventing unnecessary injury to the sinus. Cone beam CT Scan allows the implant dentist to measure precisely the amount of bone available under the sinus floor for implant fixture placement. Recently with improvements in surgical techniques and instrumentations ,a skilled implant dentist can even raise the sinus membrane without perforation . This means that longer implants can be placed in conjunction with internal sinus lift bone grafting.
The xray on the left shows multiple perforations of the sinus with mini implants. Many advocates of mini implants claim that mini implants can be inserted without flap surgery and bone grafting. The resultant quick but careless implant placement has resulted in massive sinus infection for the patient. All mini implants were removed to allow the sinus to heal .
3. Infection at Implant site
Asepsis surgical techniques.
This is another common dental implant problem.
There are many causes of implant infections. One of these could be due to bacterial contamination during surgery . Asepsis implant surgical technique is a hallmark of a meticulous implant surgeon. The operation site must be properly draped with sterile surgical drapes to minimize intra operative contamination with bacterial. Pre and post operative antibiotics cover is also important in minimizing post operative implant site infection. Generally, patients undergoing extensive bone grafting procedures are more prone to post operative infection. Patients should maintain strict oral hygiene procedures including frequent rinsing with chlorohexidine gluconate mouth wash. Patients should also avoid biting hard on the suture line during the initial healing period.
Post operative suture line opening is the most common cause of post operative implant site infection.
4. Failure of implant integration
This is one of the more common implant problem. The implant fails to fuse to the jaw bone . This usually occurs in the first few weeks. One of the main symptoms of this problem is loosening of the implant.
There are many causes of failure of dental implant integration.
Some could be due to the implant dentist factor and others due to patients’ factor. Implants will integrate with the jaw bone provided the bone cells are not damaged during the dental implant placement. Careful gentle slow speed drilling with a lot of water coolant is key to successful implant placement. At the same time , while the dental implant fixture should be firmly fixed in the jaw bone , the implant dentist must avoid placing the implant fixture too tightly in the jaw bone as implant placement with too high an insertion will kill the bone cells and hence result in the failure of implant integration.
Some patients’ factors are also important in determining the success rate of dental implant integration. Patients who are heavy smokers or heavy drinkers generally have a higher rate of implant rejection. These groups of patients have some impairment in wound healing and as such, they are more prone to implant integration failure. While diabetic patients are not a contraindication to dental implant treatment, provided their sugar level is well controlled, patients with uncontrolled diabetes are at the greatest risk for dental implant failure .
Other patients’ factors like lack of jaw bone for proper fixation of dental implant or lack of blood supply for proper wound healing are also important contributing factors to the failure of implant integration.
Excessive application of biting forces on the implant fixture during the initial few weeks of bone healing is another common cause of failure of implant integration. Patients are generally advised to go on a soft diet in the critical first few weeks of bone healing.
However, for some cases, the rejection of the dental implants by the body is unknown. This may occur in about 5 % of the cases.
When there is too much bacterial plaque around the teeth , this will result in gum inflammation and gum diseases. Similarly, with excessive bacterial plaque accumulation around a dental implant due to poor oral hygiene, the resultant gum inflammation around a dental implant is call peri-implantitis. Therefore good oral hygiene and regular periodic visit to the implant dentists for oral prophylaxis is imperative for long success of dental implants.
Prevention of peri-implantitis is important as prolonged chronic inflammation of gum tissues around a dental implant will lead to gradual bone loss and finally loosening of the dental implant . Certain patients are more prone to peri-implantitis. Generally, heavy smokers and patients with uncontrolled diabetes are more prone to peri-implantitis. Similarly, patients with thin bone and gum tissues are also more likely to experience peri-implantitis in the long term .
The treatment of peri-implantitis is quite similar to treatment of periodontitis (gum diseases)