Dealing with complications
Treatment of recessions around implants with the tunnel technique
From a clinical perspective, there is a difference between the risk factors associated with soft tissue dehiscence around implants and aetiological factors that can cause gingival recession.
Avoiding recessions: knowing the risk factors
The risk factors for tissue dehiscence around implants have been well documented (fig 5):
- thin phenotype
- lack of keratinised mucosa
- implant positioning
- thin (or lack of) buccal bone
The modified coronal advanced tunnel (MCAT) technique
The MCAT technique was first described to treat multiple gingival recessions (Aroca et al., 2010; ibid, 2013). However, it can also be performed for implant recessions.
The technique uses a full-thickness tunnelised flap, and is performed without a blade in order to keep the periosteum intact. The flap should be extended beyond the mucogingival line, where collagen and muscular fibres should be cut to free the flap from attachments. The implant surface is then thoroughly cleaned and a connective tissue graft is harvested from the palate and placed under the tunnelised flap. Finally, sliding sutures are placed to coronally mobilise the flap and completely cover the graft.
The distance between the tip of papilla to the contact point
The MCAT technique has been shown to give predictable results in multiple type III gingival recessions. The distance between the tip of the papilla to the contact point at the baseline is used as a prognostic parameter to show the root coverage achievable by the MCAT. When the distance measures ≦ 3mm in the maxilla, the probability of full coverage is 89%; in the mandible it is only 34% (Aroca et al., 2018).
MCAT and implant recessions
The speaker presented some complex cases which were successfully treated with the MCAT technique. In one case, the patient rejected the autogenous soft tissue graft and so the speaker opted to use MCAT plus collagen matrix to increase soft tissue levels six months before extraction. The tooth was then extracted and socket preservation was performed. After another six months the site was ready for implant placement, and, as the patient became more confident, a simultaneous connective tissue graft could be performed. One year after everything was stabilised, the definitive prosthesis was done.
The message is to prevent recession around implants
Proper soft tissue management before and at the time of implant placement is key. If tissue thickness is less than 2mm, soft tissue augmentation is recommended. Proper bone augmentation is also needed before and at the time of implant placement. In the absence of sufficient buccal bone wall (or if defects are present), bone augmentation is highly recommended.