Implants are now a common and predictable method for replacing natural teeth, and we are able to quote high success rates in both the maxilla and the mandible. When we refer to success, we are describing an implant that is in optimum health, aesthetic, and is restored with a restoration that is maintainable.
Our treatment planning protocols are now centred on recognising and minimising the potential risk factors that may affect the long-term success. The importance of these is heightened in an aesthetic case. The most significant risks or factors are:
Host Susceptibility: history of periodontal disease, history of peri-implant disease, uncontrolled diabetes and genetic disorders.
- Prosthetic Design: oral hygiene, retained cement, passive fit of the restoration and occlusal scheme.
- Implant Design: surface roughness, keratinised mucosa and poor surgical technique.
- Patient Factors: oral hygiene, smoking and stress.
The literature is clear that optimum periodontal health, adequate oral hygiene, smoking cessation advice and well controlled system conditions are a pre-requisite prior to implant treatment. However, is it also clear that our implant and prosthetic design is important for long-term success. The following case study highlights a number of simple ways to minimise risk factors and ensure aesthetic results.
Case study
The patient had post crowns replacing both central incisors and the upper right lateral incisor. The crowns failed and were removed by the referring dentist. The patient also disliked the conventional crowns on the upper right lateral and canine.
Two BioHorizons implants were placed in position upper left lateral incisor and upper right central, in a delayed-immediate protocol using a surgical guide. A transmucosal healing cap was placed to start to form the soft-tissue profile. The patient was temporised with a removable denture.
The implants were restored eight weeks later using the ‘3inOne’ abutment, and a cement-retained bridge that had been modified to allow access to the abutment screws was fitted. The conventional crowns on the natural teeth were also replaced.
Modifying the risk factors
There is evidence to suggest that a screw-retained bridge is never passive, irrespective of the technology or extent that the clinician may go to in order to achieve a perfect fit. However there are obvious advantages to a restoration being screw retained; these include retrievability and no risk of retained cement.
In this case the restoration is cement-retained, but also access is allowed to the abutment screws, this has several advantages:
- There is no need for a transfer jig the bridge itself can perform this function.
- There is no opportunity for the implants to spin on torquing down the abutments – the bridge will splint the implants while this is being performed.
- The restoration is passive, but still screw-retained and retrievable.
- The restoration can be removed, excess cement cleared, and the crown-abutment interface checked and polished.
Implant design and position
The angulation of the implant is critical to ensure that the emergence of the abutment screw is palatal to the incisal edge, and the three-dimensional position of the implant fundamental to ensure longterm
aesthetic results. A surgical guide is imperative to ensure this.
The implant of choice was a BioHorizons Tapered Internal as the Laser-Lok allows for predictable long-term hard and soft tissue stability.
Maintenance
Adequate oral hygiene and appropriate professional screening for early signs of peri-implant disease is required. At the fit of the restoration and at each assessment appointment probing depths, the absence and presence of bleeding on probing should be recorded and the occlusal scheme assessed.