Primary stability is defined as the capacity of the bone, in which the dental implant is inserted, to guarantee the absence of implant mobility before the osseointegration process takes place. The stability of the implant is first of all guaranteed by the properties of the bone, including bone thickness and density, qualities that allow a perfect anchoring of the implant itself.
What is primary stability
Primary stability means the stability that an implant reaches immediately after it has been placed in the bone.
During implant insertion, the surgeon generally measures the force necessary to fix it to the bone and that value will also indicate the degree of implant stability.
After 3-4 months, when the osseointegration process has been completed, the implant will be integrated into the bone and it will no longer make sense to talk about primary stability. With osseointegration we mean the process in integrating the implant with the bone; the bone, in fact, begins to grow around the newly inserted implant until it encapsulates it inside.
Low primary stability: what are the consequences for implantology?
Thanks to the planning of the implant surgery, the dentist is able to assess in advance what the quality of the patient’s bone will be. However, it is not certain that in the intervention phase the surgeon finds himself in front of a bone with the expected characteristics, able to guarantee the stability necessary to hold a crown.
In these cases the possibility of choosing between different types of dental implants sometimes allows to increase the degree of stability or to favor an adequate osseointegration process and focus on the secondary stability of the implant.
Survival rates of implants with poor primary stability
In a recent study published in Clinical Oral Implant Research, researchers analyzed implants inserted with poor primary stability and evaluated factors that could lead to subsequent implant failure.
The patients included in the study sample were 156 for a total of 169 implants inserted, the observation and monitoring time was of variable duration, over a period of time ranging from a minimum of 34 days to a maximum of 9.28 years.
In the monitoring phase, descriptive statistics were performed and the survival rate of the plant was analyzed through the Kaplan-Meier life tables and estimates. To this have been added the assessments made through imaging.
The results of the research
Of the 169 implants inserted with low primary stability originally, only seven patients had an implant failure. These data allow to affirm that the survival rate of the implants, despite the poor primary stability, is 94.74%.
Data from Kaplan-Meier’s estimates also revealed that the seven cases of implant loss occurred among the 82 advanced surgeries on complex clinical cases, while no implant failure occurred on cases of simple surgery.
Complex clinical cases and implant success
The results of this retrospective study enhance the thesis that even in the presence of low primary stability, thanks to innovative technological tools and technically advanced dental implants, it is possible to undergo a successful implant surgery.
In the presence of complex clinical cases, relying on a dental clinic with specialized skills and adequate tools can make a real difference and make it possible for interventions that are considered too difficult to perform elsewhere.
