Success of dental Implant treatment

Author Dr. Biju Thomas BDS, FFDRCS Scientific dental implant clinic

Dental implant treatment is a dream comes true for both dentists and patients. It is in 1952 this miraculous discovery by Prof. Per-Ingvar Branemark hallmarked the science of dental implantology and he for the first time coined the word Osseo-integration. Since then multitude of implant systems and their prosthetic solutions have emerged. Since then it has become the gold standard for replacing single tooth to complex full moth dental implant treatment.

Like any surgical specialty dental implant treatment has its own merits and demerits. The success rate is dependent on the scrutiny following factors.

• Proper patient selection
• Proper and meticulous treatment planning
• Pre surgical evaluation
• Certain amount of surgical discipline
• Adaptability and continuous improvement of individual treatment skills
• Knowledge and capability to handle and trouble shoot failures

What can the patient expect?

The patient has to be completely aware of the procedure, its implications, its limitations, and the final expectations of the treatment protocol. Patient should not be given unrealistic promises. The motivation and cost factor awareness of the patient has to be taken into consideration while selecting the patient

What care the implant dentist should take ?

The pre-treatment planning and the diagnostic work up should be meticulous to the point that the eventuality of an unfortunate failure should also be factored. Any implant is purely prosthetic driven, and not surgically, therefore it must be understood that the prosthetic design should respect the bio-mechanical factors that may contribute to prosthetic complications.

In this article Dr. Thomas will highlight the primary causes of implant and its prosthetic parts failures and the management of failures

Implant Failures

Description of a failed implant is as follows

• The implant should be clinically mobile
• There must be progressive bone loss

Description of a failing implant is as follows

Implant shows a progressive loss of supporting bone, but is clinically immobile

The absolute contra-indications for implant dentistry are Systemic

• Recent myocardial infarction and cerebrovascular accident,
• Valvular prosthesis surgery,
• Immunosuppression,
• Bleeding issues,
• Active treatment of malignancy,
• Drug abuse,
• Psychiatric illness, as well as
• Intravenous bisphosphonate use

LOCAL CONTRAINDICATIONS

A few have been listed-

• Para functional habits like Bruxism, clenching, etc.
• Poor motivation
• Smoking
• Poor oral hygiene maintenance despite evaluation
• Anatomic limitations

There are two types of implant failure:

Early failures and late failures
Early failures

This type of failure occurs shortly after the implants are placed. They can be caused by

• Overheating the bone
• Too much force when they are placed
• Not enough force when they are placed
• Contaminated implant
• Contaminated Osteotomy
• Epithelial cells in Osteotomy site
• Poor quality of bone
• Excessive forces during Osseo integration
• A myriad of other reasons

Late failures

Generally caused by

• Excessive forces
• Lateral loading

Early failures can be dealt with at the stage of treatment planning, and diagnostic work up, by ensuring an adequate surgical protocol, and a thorough knowledge and understanding of the implant system being placed.

It goes without saying that implant surgery, like any invasive procedure, has to follow strict surgical and sterilization protocols, with emphasis being placed on minimal interval time between exposure of the implant from its sterile packaging to its insertion and primary fixation in the Osteotomy site.

Implants should never be manipulated by gloved fingers, or the surface contaminated by external sources during the implant placement. Epithelial invagination in the Osteotomy site is a certain precursor to implant failure. Most instances of crestal bone loss usually occurring within a few weeks of placement with an improper protocol of handling.

A large percentage of failures of implants occur in the late phase or the phase of loading. The most significant factor affecting stability of an implant is occlusal loading. Having mentioned that all implants are eventually prosthetic driven, it is imperative that the occlusal scheme has to be designed to ensure axial loading, and avoid excessive occlusal forces on the implant. Early signs of excess load fatigue are manifested by loosening of abutment screws, and may eventually lead to implant fractures.

The ratio of implant to crown should be ideally 1:1 to ensure proper dissipation of occlusal forces. Short implants, with an inadequate diameter should be avoided to the greatest possible extent to prevent secondary failures due to inadequate loading. Cantilever design, especially posterior cantilevers is a precursor to failure too, and may place excessive load on the implant.

Discussion

Implant dentistry, as a science has rapidly evolved, and has heartening rate of success. However, despite all efforts, there will be the add occasion where failure of implants will occur, either due to underlying metabolic conditions, local factors, inadvertent load on the implant during the no-load phase, or a combination of local, and systemic factors. The emphasis should be on mitigating the chances of failure by fool-proof measures, and honoring the technique sensitivity, as well as the procedure protocol for the implant system being used.

Failures in implant dentistry can prove expensive and distressing for both the operator, as well as the patient. Emphasis on pre procedural planning and system checks, as well as intra operative and post loading precautions will go a long way towards a satisfying outcome.