Contraindications to implant treatment

Contraindications to implant treatment

INTRODUCTION

Before deciding whether to have an implant, it is essential that the practitioner knows the patient’s psychological profile, their medical and surgical history and their reasons for choosing the implant (aesthetic and/or functional). To do this, a complete and precise anamnesis remains the only way. It must allow the practitioner to immediately recognise the pathologies or situations that constitute an absolute contraindication to implant placement, those that constitute a relative or temporary contraindication and those that are simply risk factors for failure of the implant treatment.

Contraindications to implant treatment

1. ABSOLUTE CONTRAINDICATIONS

A pathology is considered an absolute contraindication to implant placement when it can induce a vital risk in the patient or when his state of health can be responsible for a systematic failure of the implant procedure and harm osteointegration.      ( Budoin and Bennanni, 2003)

1. General contraindications
2. Heart disease

Wearing a valve prosthesis, patients with a history of esclerotic endocarditis, severe heart failure, severe cardiac arrhythmia. 

2. Blood diseases

 Including severe anemia, neutropenia < 1000 /mm3, thrombocytopenia (<50000)/mm3)

3. Chronic renal failure

The kidney plays an important role in maintaining the composition of physiological fluids and is significantly involved in the metabolism of Vit D; CKD leads to bone metabolism disorders (secondary hyperparathyroidism) with immunodepression, a risk of hemorrhage and anemia which can disrupt osteointegration, in addition to the heavy treatment and possible viral infections linked to it.

4. Patients who have undergone irradiation at the cervicofacial level

Irradiated bone is fragile (hypoxia, hypocellularity, hypovascularity) and the oral cavity is subject to changes. These two elements make the implant solution unlikely. But some authors take into account several factors before making a final decision; among these factors are dosimetry, the irradiated area, the age of irradiation, the general condition, and comorbidity. 

5. Patients undergoing chemotherapy

It is clear that no implant placement is possible during chemotherapy due to bone marrow aplasia and blood squamous cell disorders. It is necessary to wait at least 6 months after stopping chemotherapy to consider implant surgery.

6. Patients taking antiresorptive drugs

The risk of spontaneous bone necrosis of the maxillary bones rejects any idea of ​​implant placement in patients taking intravenous bisphosphonates and antiangiogenics. 

It should be noted that an implant already in place in these patients does not constitute a risk, so it should not be removed.

7. Patients on immunosuppressants

These are transplant patients in whom immunosuppressive treatment is maintained for life. The delayed healing and the risk of infection in these patients require caution and the choice of a prosthetic restoration solution other than that of the implant. 

8. Bone pathologies

Osteomalacia, Paget’s disease, brittle bone disease…

Osteoporosis is rarely located in the jaw, but it can become a contraindication factor when its treatment includes bisphosphonates.

9. Acute hepatitis

In their acute form, they are an absolute contraindication, due to disorders of coagulation factors, delayed healing and the risk of cross-infections. 

10. AIDS

When the CD4 count is less than 200, implant placement is contraindicated because immunity is low. Beyond that, implant placement can be discussed taking into account other local and general factors.

11. Chronic alcoholism

Chronic alcoholism may constitute an absolute contraindication due to possible liver function disorders, immunosuppression, changes in the oral environment, etc. If a patient is known to have chronic alcoholism, implant placement will only be possible if the addiction is definitively treated.

12. Drug users

These patients are often unstable, with insufficient or even absent oral hygiene and periodontal diseases, they are also predisposed to infections (HIV, hepatitis) and their immunity is in most cases deficient.

13. Psychological disorders

It is difficult to be on the same wavelength with these patients and their expectations are sometimes unrealistic, which requires caution in decision-making, at the risk of finding yourself faced with an eternally dissatisfied patient. 

Contraindications to implant treatment

2. RELATIVE OR TEMPORARY CONTRAINDICATIONS

A pathology or clinical situation is considered a relative or temporary contraindication to implant placement when it is unstable or compromises surgery. The implant can only be considered if the pathology or clinical situation is stabilized and the case re-evaluated, thus protecting the patient from a vital complication and the implant from systematic failure of osseointegration. 

2.1. GENERAL CONTRAINDICATIONS

2.1.1. Cardiac pathologies

Myocardial infarction less than 6 months old, angina pectoris when unstable, coronary insufficiency and stroke which becomes questionable from the 6th ^month .

Please note:

In patients on anticoagulants, the risk of bleeding increases with the number of implants to be placed (INR < 4).

Antiplatelet drugs are not dangerous and do not even need to be stopped.

2.1.2. Uncontrolled diabetes

When diabetes is unstable, it is best to discuss the case with the treating physician and see if it is possible to improve the balance of the disease (HbA1C around 7). We must not forget the risk of periodontitis in unstable and poorly balanced diabetic patients, as well as the risk of hypoglycemia that can occur during the procedure, especially if the procedure is long, this requires good organization of the implant placement session.

2.1.3. Oral bisphosphonates

According to AAOMS 2014 data, since the risk of bone necrosis related to oral bisphosphonates is low, implant placement is discussed by assessing this risk and taking into account comorbidities. In the case of implant placement, treatment is stopped 2 months before and the patient must be informed about the risk of bone necrosis. 

2.1.4. Particularities: Physiological states 

The child: according to the HAS, vertical bone loss and infraclusion of implant-supported teeth require waiting until the end of growth, around 18-20 years of age.

Elderly people: people in their 3rd ^or 4th ^years may constitute a contraindication or a risk factor for implant placement. However, the risk of implant failure is not directly linked to the age of the patients, but rather to possible pathologies, current medication or the quality of healing which may be reduced.

Pregnancy: Implant placement is not an emergency, so it is best to wait until after delivery.

2. LOCAL RELATIVE CONTRAINDICATIONS
3. Oral hygiene

It should be taken as a contraindication, as it plays an important role in the long-term durability of implant reconstructions. It is important to explain it to patients and to motivate those whose hygiene is insufficient before surgery. Hygiene must be maintained even after implant placement.

2. Chronic periodontitis

It exposes to the risk of cross-infections and contamination of the implant. The infection should be treated and stabilized to avoid peri-implantitis and ensure medium and long-term success.

3. Oral mucosal pathologies

Any pathology of the oral mucosa must be taken care of before the intervention.

The frenulums and bridles should be dissected beforehand, as they can exert continuous traction on the implant site.

4. Infections of neighboring teeth

Any infection on a tooth near the implant site must be treated before surgery .

4. Special anatomical situations

Prominent sinus, thin, knife-edge or insufficiently high bony ridges, 

the proximity of the alveolar nerve… are anatomical situations unfavorable to implant placement but which can be resolved by pre-implant surgery.

5. Special features 

Gag reflex:

It is necessary to simulate the act before the definitive surgery and to think about premedication. It can become an absolute contraindication.

ATM and Oral Opening:

If the oral opening is limited, it can be an obstacle to surgery and the creation of the prosthesis, especially when it comes to the posterior sector. It is necessary to simulate the gestures before surgery to ensure its feasibility. 

Contraindications to implant treatment

3. RISK FACTORS

Risk factors are “special situations” where surgery remains possible but may jeopardize the durability of the implant. These risk factors should be identified and taken into account before the final decision to place an implant. 

3.1. Tobacco 

The effects of tobacco on the mucosa and the oral environment are well known (trophicity disorders, local ischemia, delayed healing, risk of infection, etc.) in addition to more severe periodontal diseases and insufficient or even absent oral hygiene in some smokers. All these elements expose to bone loss around the implant. Studies have shown that beyond 10 cigarettes per day, the risk of failure increases by 50%. It is advisable to stop smoking 1 week before surgery (nicotine substitutes can be used) and for the 8 weeks that follow. In the event that the patient refuses to stop smoking, it is advisable to warn him of the possibility of shortening the duration of osseointegration. 

2. Aggressive periodontitis

Despite treatment of aggressive periodontitis, the risk of implant failure persists. 

3. Bone density and quality 

Bone quality and density play a role in the stability and osseointegration of the implant. 

Dense bone (middle and posterior mandibular region) provides good primary stability, but osseointegration is slower. On the contrary, spongy bone (middle and posterior maxillary region) provides primary stability with less difficulty, but osseointegration leading to secondary stability occurs more quickly. 

There are several classifications that can be used to assess bone density:

1. The classification of Lekholm and Zarb (1985) is the oldest. It includes 4 categories of bones:

                            Type 1 Type 2 Type 3 Type 4

Bone type 1: corticalized bone (dense)

Bone type 2: thick layer of cortical bone surrounding a core of trabecular bone

Bone type 3: thin layer of cortical bone surrounding a large trabecular core

Bone type 4: very thin layer of cortical bone surrounding a very large trabecular core

2. Mish’s 1998 classification takes into account tactile perception during drilling.
3. The simplified classification of Trisi and Rao from 1999 which now includes only 3 types of bone: dense bone, normal bone and low density bone.
4. Bone warm-up  

Bone heating can occur when drilling and/or screwing the implant . This can be avoided, among other things, by irrigation, the use of unworn drills, tapping, etc. 

5. Prematurity and parafunctions 

The implant is exposed to either mobility or long-term risk of fracture. 

6. Bruxism

Bruxism can cause implant fracture and loss of osseointegration which can be avoided by increasing the number of implants in the posterior sector, implant solidification, premolarization and wearing a night guard. 

CONCLUSION

It is very important to know the patient’s motivations, requirements and wishes before making the decision to place implants. In the event that the patient has a pathology, one should never hesitate to contact their doctor and any local oral constraints should be removed. In the event of the slightest doubt, the best therapeutic choice is to replace the implant with a conventional prosthetic solution and never give in to pressure from patients. 

Contraindications to implant treatment

  Wisdom teeth can be painful if they are misplaced.
Composite fillings are aesthetic and durable.
Bleeding gums can be a sign of gingivitis.
Orthodontic treatments correct misaligned teeth.
Dental implants provide a permanent solution for missing teeth.
Scaling removes tartar and prevents gum disease.
Good dental hygiene starts with brushing twice a day.
 

Contraindications to implant treatment