Reducing microbial infection for implant patients

implant patientAshok Sethi discusses how a conical connection can ensure aesthetic, long-term health and stability for implant patients.

Implant dentistry has become mainstream as the chosen method of replacing missing or failing teeth. But with this popularity comes an increase in complications. One of these is the incidence of peri-implant infection.

One of the most significant advances in implant dentistry has been the development of surfaces that enable contact osteogenesis. In other words, this is the direct contact of bone to implant. This has revolutionised our ability to immediately place and load implants. Unfortunately, this surface also attracts bacteria, which may be one of the reasons for the increase in peri-implant disease.

We must have sound strategies for minimising the risk posed to patients by bacterial infections.

The implant system

The Myplant Two device is a rough-surfaced implant that permits contact osteogenesis. Equally important is the macro design. This consists of a tapered body with a progressive thread that enables extremely high primary stability.

Furthermore, it comes with a range of abutments that are conically connected to the implant. This provides a tight seal between implant and abutment. This also facilitates the selection of an abutment from a range of angles and the sulcus heights to permit immediate restoration.

Clinical case study

  • Figure 1: Occlusal view of the fractured central incisor with sub-gingival fracture line

Surgical treatment

Immediate implant placement to replace a failing tooth is a very attractive option for patients – even more so if the implant can be loaded immediately.

The patient in this case attended with a fractured central incisor. A sub-gingival extension of the fracture line rendered the tooth beyond salvage. Treatment required 3D imaging and interactive planning using Simplant software.

A hollow acrylic transitional restoration was constructed to be fitted at the time of placement.

The osteotomy was carried out based on site selection and bone density determination from the CT scan. Verification of the density was carried out manually during osteotomy preparation.

Accurate fit

The implant was inserted to a torque of 30Ncm. The preselected abutment was verified with the trial abutment and inserted to torque of 15Ncm to engage the conical taper.

It should be noted that this is a non-indexed abutment that will create a very tight seal preventing micro-leakage between the implant and the abutment.

The positioning of the implant below the level of the bone thus becomes a viable option – ensuring that bone will develop above the level of the implant and protect it.

A prefabricated sleeve on the abutment was used, onto which the hollow acrylic transitional restoration was relined with auto polymerising acrylic. This ensured an accurate fit and enabled the transitional restoration to create a seal around the gingival margin, allowing the blood clot to be contained within the socket.   

A healing period of three months ensured that integration had taken place, after which the implant was definitively restored.

  • Figure 7: Hollow acrylic transitional in situ. Note that the transitional restoration is in contact with the gingival margins, ensuring that the blood clot is contained within the socket to enable bone to form as a natural healing process

Restorative phase

A conically-retained crown is considered to be the most effective way of attaching a prosthesis to the abutment because the tight fit does not permit micro-leakage. It is a secure connection, as used in all the engineering world. Most importantly, it is simple and efficient to use.

It requires a pick-up impression of the conical gold coping that has been seated on the abutment, which is then cast with pattern resin and a dowel pin in the coping within the plaster model.

The technician then fabricates the restoration of choice – in this case, a porcelain fused to metal crown and connected permanently with a composite cement to the gold coping.

The crown is delivered to the surgery and inserted very simply by using pressure and percussion to engage the conical taper. The implant is thus protected by a delicate hemidesmosomal attachment of the soft tissues to the abutment and a more robust growth of bone over the implant.

  • Figure 10: The definitive restoration. A metal ceramic crown has been fabricated and permanently attached to the precisely fitting gold coping. The delivery of the definitive restoration will require no cement or screws with their attendant disadvantages

Summary

This technique eliminates the micro leakages associated with screw retention and also the risk of excess cement with cement retention.

The idea is, therefore, to protect the implant against microbial infection.      


This article first appeared in Implant Dentistry Today. You can read the latest issue here.

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