|Year : 2017 | Volume
| Issue : 1 | Page : 1-2
Short implants: Are they worthy alternatives?
Editor-in-Chief, JDI, ProSmile Dental Clinic and Implant Centre, Dr. L H Hiranandani Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||13-Feb-2018|
Editor-in-Chief, JDI, ProSmile Dental Clinic and Implant Centre, Dr. L H Hiranandani Hospital, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Shetty S. Short implants: Are they worthy alternatives?. J Dent Implant 2017;7:1-2
Edentulism whether partial or total have been successfully rehabilitated with osseointegrated implants with favourable long-term prognosis. Nevertheless, there have been failures with them from early to delayed. Available bone volume has been the most important criteria for selection of the implant for any site. Anatomic limitations like the floor of the pneumatizing maxillary sinus, inferior alveolar nerve and nasal floor lead to reduced vertical height of available alveolar bone and subsequently the implant length selection. Though additional surgical procedures like sinus floor elevation and augmentation, vertical and horizontal ridge increasing procedures have proved to be successful, they entail additional morbidity, surgical and healing time and costs. Instead, zygomatic, pterygoid and short implants have been recommended.
Shortened implants appear to be the simplest viable solutions in patients with resorbed ridges who are unwilling to undergo additional procedures. There have been variable success rates associated with their use ranging from 83% to 93% compared to the conventional length implants of 96 to 99%. Most failures occurred after loading and not during the integration phase. But there are relevant and hesitant considerations for the use of short implants such as:
- What is the minimum length of implants that would work in a particular quality of bone?
- Is there an overload of occlusal forces on short implants?
- Can they be used as a solitary implant?
- Can they be immediately loaded?
Shorter implants mean - less primary stability due to reduced bone-to-implant contact (BIC), lesser resistance to bending forces and easier micromotion on early loading.
The long-accepted length of 10 mm as the minimum critical length of implant has seen a gradual change due to improved surgical protocols and surface enhancements of short implants. Implants ranging from 8 mm, 7 mm, 6 mm and 5 mm are available. The easy availability of these implants and with insufficient long-term results have led to rampant use of these in many unfavourable situations. Due to the guarded prognosis, the following factors need to be considered while placing short implants.
- Location of the implants in the jaw – Posterior maxilla will have the poorest prognosis due to the more rarefied bone as compared to mandibular posterior region and anterior maxilla. The possible combination of indirect sinus floor elevation by 2-4 mm with or without bone augmentation can increase the choice of implant length. Osseodensification is another accepted procedure to improve the primary stability and BIC
- Diameter of implants – Implants greater than 4 mm diameter allow to compensate for the shorter length and improve the surface area of the implants and in turn increase in the BIC
- Implant design and surface characters – Aggressive thread designs and improved surface treatment have ensured enhanced primary stability and faster healing
- Number of implants – Solitary implants are discouraged due to biomechanical disadvantages. Splinting of implants are recommended for favourable dissipations of occlusal loads and avoid overload on individual implants
- Favourable occlusal schemes – Achieving axial loading, reducing occlusal contact areas with narrower tables, recruiting natural dentition for primary stress loaders, elimination of lateral contacts and avoiding cantilever designs permit avoidance of destructive occlusal forces
- Presence of parafunction – Excessive loads are detrimental to the bone-implant interface and hence short implants are avoidable
- Prevention – Implant at an early stage or immediately post extraction should be advised to avoid choice of short implants
- Compulsory education in implant science – Lack of adequate knowledge across clinicians leads to delayed choice of implants and unfavourable local factors. It will also dispel biases, commercial-driven beliefs and encourage fact-finding habits and appreciate the risks and benefits of particular cases. This will lead to low percentages of patients needing shorter implants.
Also, with the ever-increasing life expectancy of patients, artificial substitutes like implants do need to last longer and hence institution of any therapy needs to be analysed well and undertaken. Hence in view of the limitations of short implants, a thorough evaluation of benefits of short implants alone or with any other minor interventions should be considered and offered to patients than just doing it haphazardly in all cases. Nevertheless, more evidence-based long-term studies should be published by astute clinicians for the benefits of fellow implant dentists to help them in judicious decision-making for the better care of the patients. These should include performance of implant restorations complex and not just implant survival rates. Besides biologic changes like marginal bone loss every year, catastrophic periimplantitis, mechanical failure like screw-loosening and fracture, restorative failures, esthetic and maintenance failures which are more common with short implants, should not be overlooked.
“Always trying new things is always more fun, and it can be scary, but it's always more fun in the end.”