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Reasons why not to have Implants

So after months of deliberating, you have finally decided to go ahead and get your implants done. You have decided on the type of implants, agreed on the cost, and settled on the dentist that is going to do the procedure for you.

Everything seems to be going smooth...right?

Have you had your medical history checked through?

Before the start of every dental consultation, we always take a comprehensive and thorough medical history. This is extremely important. If your dentist has any doubts, he or she may ask to contact your physician before any dental treatment is done.

There are some scenarios where you should NOT do any implants. These are usually due to  underlying medical issues. We call these medical contraindications.

There are cases where implants cannot be done at all (absolute contraindications) and cases where doing implants are risky but may be done (relative contraindications).

In this article, we shall go through some common cases that we see. If you think that you have any of these conditions, do raise them to your dentist! It is better to be safe than sorry.

Patients who have had prior and recent radiotherapy done to the head and neck region:

A (relatively) commonly occurring cancer in the Chinese population in Singapore is Naso-Pharyngeal Carcinoma (NPC). It is a cancer involving the area between the nose and the pharynx. Chinese people, especially Cantonese, have been shown to be more susceptible to NPC.

Radiotherapy is commonly performed to treat NPC. Radiotherapy involves the use of radiation beams to kill the cancer cells. Unfortunately, this radiation beams also affect the normal structures around the cancerous cells.

Patients who have had radiotherapy done to head and neck region should NOT have implants done.


Radiotherapy affects the metabolism, turnover, and recovery of bone. Hence, we try to avoid procedures that result in bone injury and manipulation, namely extractions.

Implant surgery also involves the manipulation of bone, predisposing patients to risk of ORN. Potentially a serious condition that can cause widespread infection of surrounding bone.

The risk of ORN decreases over time. Recent studies have shown that for patients who have had radiotherapy done a long time ago, dental implants may be done, but there is still a risk.

If you have any doubts, please discuss this issue in detail with your dentist!

Bisphosphonate therapy

Bisphosphonates are a class of drugs taken by two main groups of patients: those with age induced osteoporosis, and cancer patients.

Bisphosphonate drugs may go by multiple names. Listed below are some of the more common ones:
- Alendronate (Forsamax)
- Zolendronate (Zometa)
- Ibandronate (Bonviva)
- Risedronate (Actonel)

Similar to radiotherapy, bisphosphonate drugs affect the metabolism and turnover of bone. Extractions or implant surgery done in such patients predispose them to the risk of infection and delayed healing of the exposed bone.

Bisphosphonates may also be given in two forms: the oral route and via the IV route.

Bisphosphonates via the oral route are usually given to treat milder forms of disease like osteoporosis and osteopenia. These drugs are commonly given to the elderly. In these cases, implant surgery may be considered as a relative contraindication - meaning that although risky, they may be done. Numerous studies have shown success of implant placement in these group of patients. Studies have shown that the risk of bone infection is very low.

On the other hand, bisphosphonates given via the IV route is considered an absolute contraindication to implant placement. The IV route is usually given to patients suffering from more severe forms of disease like cancer of the bone.


For implants to be done, we require a healthy and functioning immune system. This is to aid in recovery after the implant surgery. The large majority of our patients will have no problems with this.

However, in those with weakened and compromised immune systems, implants cannot be done.

What causes a compromised immune system? Listed below are some examples:
- Patients with HIV/AIDS
- Bone marrow transplant patients
- Heavy intake of steroids
- Congenital diseases

In these cases, placement of implants may lead to infections and poor wound healing.

Recent heart attack/heart surgery

We try to avoid elective dental procedures as much as possible if the patient has had a recent heart attack or heart surgery.

This is because the risk of death and mortality is much higher during this period of 6-12 months after heart attack or heart surgery.

We will highly recommend seeking alternatives or delaying implant surgery.

Heart transplant/ valve surgery
Similar - see above.

Bleeding risks
If you are on certain blood thinning medications, we may have to seek clearance from your physician before implants can be done.

Common names of blood thinners:
- Warfarin
- Apixaban (NOAC)

If you are taking these blood thinners, remember to raise it up to your dentist!

Certain precautions may have to be taken in view of your increased bleeding risk. In serious cases, implant surgery may have to be postponed until you complete your course of medications.


Patients who are currently treated for active cancer usually will not have implants done.

Cancer drugs often affect the immune system of a person. This increases the risk of post-operative infections. Healing of the wound is also affected, and failure rate is much higher.

Other contraindications
- Uncontrolled Drug/alcohol abuse
- Uncontrolled Psychiatric disorders

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