Revisiting implant controversies
Staged placement approach
As clinicians, our goal is to achieve perfect aesthetics and a high-scoring PES index (Fürhauser et al., 2005). To do this, extra soft tissue is required after rebuilding the hard and soft tissues. This is because the ideal soft tissue profile is achieved by pressure moulding it with the final suprastructure. To this end, the speaker recommended a one-piece crown with a convex transmucosal zone to push the tissue up during the prosthetic procedure.
Immediate implant placement is feasible, but… it should be performed with soft tissue augmentation and a staged approach. Otherwise, the extra soft tissue that is required will not be available in the prosthetic phase. The speaker said that we should let the soft tissue graft heal for four months before connecting the final suprastructure.
The current trend to use immediate implants/restorations in almost every case is adventurous
According to the speaker’s practice, about 10% of cases in the aesthetic area are treated using immediate implant placement (only those with no defects in the buccal bone or plate). 85% of cases do show buccal bone defects, and so are treated by early implant placement plus GBR. In the 5% of the remaining cases, neither perfect implant placement nor stabilisation of the membrane are possible, and so they are treated with a staged approach.
Biological limitations require a step-by-step approach
High probing values indicate that attachment is lost and bone is deficient. When extracting the involved teeth, additional high levels of remodelling will occur, meaning that immediate implants are not recommended. Further, if adjacent teeth must be extracted insufficient interproximal buccal bone will lead to loss of buccal papilla due to lack of support (Grunder et al., 2005). Buccal bone should be augmented first, and soft tissue volume increased next in a staged approach. This, the speaker said, is the only way to predictably ensure outcomes.
A non-resorbable and 3D-shaped membrane is needed for successful GBR
In most cases, the resorption time of the membrane greatly influences the outcome. The speaker outlined several cases with a minimum healing time of six months before membrane removal. Some native collagen membranes lasting less than two months may be useful for other applications. However, a very predictable way to pre-form the new bone as required is to use a titanium-reinforced PTFE-membrane. This is because it is non-resorbable and can be shaped in 3D. No biomaterials are required underneath.
The new bone formation (beyond the genetically determined skeletal envelope) has several requirements (fig 1):
- blood clot protection to prevent soft tissue from going into the space
- space maintaining, so volume is not lost as the space collapses
- stabilisation throughout the healing period
- time (especially when bone is to be created outside the skeletal envelope)
Flap design is key. The flap should be released in order to cover the augmented space in a tension-free way. This is a technique-sensitive procedure.
But it is not only bone that is needed: a subepithelial connective soft tissue graft is also needed (fig 2). In order to quickly harvest a uniform graft from the palate the speaker uses a mucotome (Mörmann et al., 1977) to de-epithelialised the area in the lateral palate as shown in Zuchelli’s well-known procedure before harvesting the subepithelial connective soft tissue.
It’s all about case selection. When no buccal bone defects are present, immediate implant placement can be used in the aesthetic zone; however, the speaker said he always performs a simultaneous soft tissue graft and observes a four-month healing period before commencing the restoration procedure. When bone defects are present, the speaker prefers to: extract the tooth; wait two months for soft tissue healing; perform implant placement plus bone augmentation; wait six months and then perform the soft tissue graft; and then one month later start the second stage procedure. So, the total treatment time can last up to one year (fig 3).
The speaker emphasised the importance of timing for ideal aesthetics, and urged the audience to take their time.