BACKGROUND The importance of keratinized tissue around teeth and dental implants is
a frequently investigated topic in the literature. The need for an adequate amount
of peri-implant keratinized mucosa (PIKM), which is defined as a minimum width of 2
mm is demonstrated according to a recently published systematic review and consensus
report.
The standard of care in the PIKM augmentation is the apically repositioned flap
(ARF) combined with a free gingival graft (FGG), as it represents a predictable and
documented strategy to gain KT width. However, such technique implies the harvest of
abundant autogenous grafts, and is frequently associated to sub-optimal aesthetic
results due to the poor color mimicry of the grafted tissue.
In light of such limitations, some alternatives based on the use of soft tissue
substitutes have been proposed, with the aim of reducing surgical invasiveness
through the avoidance of large autogenous grafts and improving aesthetic outcomes.
Among those, the sole use of as xenogeneic collagen matrices (XCM) has been
associated with promising clinical outcomes albeit with lesser KT width gains as
compared to autogenous FGGs.
Recently, a novel approach called the Strip Technique (ST) has been introduced,
where the exposed periosteal bed of a ARF is covered with the combination of a
xenogeneic collagen matrix and a 2-3 mm wide strip of autogenous free gingival
graft, sutured at the apical border of the matrix. The rationale for this "combined
grafting technique" stands on reducing surgical invasiveness and improving color
mimicry through the use of a XCM, while providing a source of autogenous
keratinizing cells in the apical border of the grafted area to promote better PIKM
gains. Albeit this new approach seems promising, there is limited evidence regarding
its clinical efficacy and there is a lack of knowledge regarding how the adoption of
such combined approach affects the re-perfusion of the grafted tissue and the
overall microvascular healing of the surgical site.
Furthermore, the pattern of the revascularization of both the autologous grafts and
the XCM requires further understanding. Most of our recent knowledge comes from
classical animal studies that evaluated the microvascularization of FGG when placed
over periosteum with microscopy. The postoperative blood supply of these free grafts
is of key importance to their survival.
Recently a new non-invasive technique has been introduced in the field of medicine
and dentistry the Laser Speckle Contrast Imaging (LSCI) system, that provides
further understanding on the dynamics of postoperative blood supply of the applied
grafts and elucidate regarding the healing pattern of the strip combination
technique.