A. L. Dumitrescu, Liviu Zetu and Silvia Teslaru
14
the general utility of this technology for gingival recession defects (Danesh-Meyer and
Wikesjo, 2001).
To eliminate the need for a second surgical procedure to remove a nonresorbable
membrane, the use of various bioabsorbable materials has been proposed (Kassab et al.,
2010).
The majority of studies evaluating bioresorbable membranes for treatment of gingival
recession defects are case studies typically involving only few subjects. The variety of
biomaterials complicates any comparisons between studies as the materials may differ in
physical properties including biocompatibility, cell exclusion, clinical manageability, tissue
integration, space provision, space maintenance, and bioresorbtion, all of which may
inffluence their ultimate relevance as GTR devices. Root coverage among the studies using
bioresorbable membranes averaged 2.8±1.2 mm. CAL gain averaged 2.5±1.3 mm. As
observed for nonresorbable membranes, probing depths remained shallow following the GTR
protocol. Bioresorbable membranes appear less effective than the nonresorbable membrane
technology in more limited gingival recession defects, however this relative deficiency
appears compensated in advanced defects. As observed for the nonresorbable membrane
technology, keratinized gingiva increases slightly following GTR using bioresorbable
membranes. This increase, however, appears to be smaller than for nonresorbable
membranes, several studies actually reporting no effect or decreased keratinized gingival
post-treatment (Danesh-Meyer and Wikesjo, 2001).
Studies comparing GTR and subepithelial connective tissue graft suggest that both
protocols offer means of obtaining root coverage of gingival recession defects. It appears,
however, that the subepithelial connective tissue graft protocol provides improved root
coverage over that observed following GTR. The subepithelial connective tissue graft
protocol also results in a substantially increased KG compared to only incremental
improvements following GTR. A possible explanation for these observations may be the
occurrence of membrane exposures and ensuing compromised wound healing following GTR
(Danesh-Meyer and Wikesjo, 2001).
In a meta-analysis on forty studies, Al-Hamdan et al. (2003) revealead that guided tissue
regeneration-based root coverage resulted in an average of 74% recession depth reduction,
41% complete root coverage, 3 mm CAL gain, and 1 mm keratinized gingival gain. Both
guided tissue regeneration-based root coverage and conventional mucogingival surgery
produced significant (
P
<0.05) improvement compared to baseline measurements. Compared
to guided tissue regeneration-based root coverage, conventional mucogingival surgery
resulted in significantly (
P
<0.05) increased keratinized gingiva (2.1 mm vs. 1.1 mm), root
coverage (81% vs. 74%), and percentage of defects with complete root coverage (55% vs. 41
%). Use of absorbable membranes, root conditioning, shallow pretreatment recession (< 4
mm), and corporate sponsorship all resulted in significantly (
P
<0.05) improved percentages
of sites with complete root coverage but had no effect on other parameters.
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