Revisiting implant controversies
Immediate placement approach
Immediate implant placement is controversial, since the clinical evidence we have is relatively low – population sizes are too small in the studies – and almost every conclusion is based only on case series. The speaker stated that they would not review the existing literature but would present his own experience and studies.
Looking for predictability: reducing technique sensitiveness
We all want predictability for our patient’s well-being, and we want to prevent failures. Immediate placement in the aesthetic zone is considered to be very technique-sensitive. It largely depends on the operator, which makes predictability difficult to achieve. But what we need are treatment procedures with universal reproducibility: treatments where people can rely on getting the same results across the board. This is what the speaker claims to have achieved with new implant and attachment designs.
The chamber concept: more space, better soft tissue formation
The speaker illustrated designs using the ‘chamber concept’ (Degidi et al., 2013). The ‘chamber’ is a three-dimensional biological space produced by combining:
- Sub-crestal implant placement
- Narrow-diameter abutments
A larger space is then left to be occupied by the blood clot, to allow the formation of new connective tissue (fig 4).
Then, the provisional is made using a special conometric coping retained by friction on the abutment. This removes the need for cementation (which could disturb this biological space).
Immediate implants with immediate loading in the aesthetic area: a protocol that works
The speaker then outlined the key factors for immediate placement with immediate loading in the aesthetic zone:
- Surgical procedures should be flapless, to maximise vascularisation in the buccal wall
- Primary stability must reach ≧ 25Ncm. To measure the implant stability, the speaker proposed a new parameter: variable torque work (VTW) (Degidi et al., 2013). VTW is the integral of the insertion torque curve during implant insertion. This measure seems to be more representative of the torque work required to insert an implant in the bone (as it represents the progressiveness of the curve). Further, square threads and a morse taper are important features for preventing implant micromotion (fig 5)
- Implants should be placed sub-crestally and anchored to the lingual cortical bone, far from the buccal wall and 2–3 mm deep (Degidi et al., 2011 /A)
- The vestibular gap should be filled by packing the graft particles in the middle and apical areas. The cervical space is part of the chamber and should not be filled
- Platform switching works, but must be used along with leaving the chamber space free for the connective tissue
- ‘One abutment, one time’ (Degidi et al., 2011 /B, 2014). The abutment should be placed simultaneously with the implant and not removed. Provisional and definitive prostheses are made over it. This concept is particularly effective with narrow abutments
- Immediate loading is beneficial when the implant is placed properly (Degidi et al., 2009)
- Gap-free restoration: the speaker’s conometric concept can be used, which avoids cement and screws. The protocol is based on conical copings with friction fit over the abutment
But there are limitations which should not be overlooked
The buccal bone wall should be intact. If it is partially lost, some cases may be possible to proceed with the protocol. But if it is completely lost, it would be unsafe to proceed.
Soft tissue should be favourable (or at least neutral). If there is insufficient soft tissue, the case will be more complicated and hence technique-sensitive. As a general rule: more complicated cases are more technique-sensitive, and so are less predictable.