Tetracycline is known to be effective in eliminating periodontopathogens and have
collagenolytic activity. This study was performed to observe the desorption kinetics and
structural changes of tetracycline-treated barrier membranes for guided tissue
regeneration.
Four kinds of barrier membranes were tested: Tefgen (American
Custom Medical, USA) and Gore-Tex (W.L. Gore & Associates Inc.,
USA) as nonresorbable membranes: Resolut(polyglycolide & polylactide copolymer, W.L.
Gore & Associates Inc., USA) and Biomend (collagen, Collatec Co., USA)
as resorbable membranes. The membranes were cut into discs( diameter: 4mm) and
were immersed in 5% tridodecy]methylammonium chloride(TIMAC) ethanol and air-dried,
The membrane discs were absorbed with l00㎍/㎖ tetracycline solution(pH 8) for one
minute and dried. For desorption kinetics, TC treated discs were immersed in phosphate
buffered saline solution(PBS, pH 7.4). PBS was exchanged daily and TC concentration
was measured by absorbance at 276nm on UV spectrophotometer.
To measure remaining antibacterial activity, discs of 1 day to 4 weeks after
desorption were placed on Mueller Hinton agar containing Bacillus cereus and incubated
aerobically in 37℃ for twelve hours and the inhibition diameters were measured. To
observe the structural change of membranes after TIMAC treatment or immersion in
PBS, the membrane discs were examined under SEM.
The results were as follows:
1. Total amounts of TC absorbed into membrane discs(O.7536㎟) were 2000㎍, 1300㎍
2625㎍ and 2499㎍ for Tefgen ,Gore-Tex , Biomend
and Resolut .
2. The concentration of TC released from barrier membrane discs was maintained over
4㎍/㎖ until the fifth day in nonresorbable membranes and Resolut , but
until the fourth day in Biomend . Until the ninth day in nonresorbable
membranes and until the seventh day in resorbable membranes, the TC concentration
was maintained over 1㎍/㎖.
3. The four membrane discs in the first day showed similar size of inhibition zone. One
to four weeks later, the inhibition zone was much smaller in resorbable membrane discs
than nonresorbable membrane discs.
4. Any structural change due to treatment of TIMAC was not observed on the
nonresorbable membranes. Resolut did not show any structural change
except fibrillar loosening during immersion period, but Biomend showed destruction of
membrane structure from the first week of immersion.
This study indicates that tetracycline treated barrier membranes lead to the sustained
release of tetracycline for over 7 days. This slow release pattern of tetracydine may
contribute to the favorable clinical outcome of guided tissue regeneration.
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