Microbiology
Chlorhexidine gluconate is active against a broad spectrum of microbes. The
chlorhexidine molecule, due to its positive charge, reacts with the microbial
cell surface, destroys the integrity of the cell membrane, penetrates into the
cell, precipitates the cytoplasm, and the cell dies. Studies with PerioChip
showed reductions in the numbers of the putative periodontopathic organisms
Porphyromonas (Bacteroides) gingivalis, Prevotella (Bacteroides) intermedia,
Bacteroides forsythus, and Campylobacter rectus (Wolinella recta) after
placement of the chip. No overgrowth of opportunistic organisms or other adverse
changes in the oral microbial ecosystem were noted. The relationship of the
microbial findings to clinical outcome has not been established.
Pharmacokinetics
PerioChip releases chlorhexidine in vitro in a biphasic manner, initially
releasing approximately 40% of the chlorhexidine within the first 24 hours and
then releasing the remaining chlorhexidine in an almost linear fashion for 7-10
days. This enzymatic release rate assay is an experimental collagenase assay
that differs from the Regulatory Specification's Agar Release Rate Assay. This
release profile may be explained as an initial burst effect, dependent on diffusion
of chlorhexidine from the chip, followed by a further release of chlorhexidine
as a result of enzymatic degradation.
In an in vivo study of 18 evaluable adult patients, there were no detectable plasma or urine levels of chlorhexidine following the insertion of 4 PerioChips
under clinical conditions. The concentration of chlorhexidine released from
the PerioChip was determined in the gingival crevicular fluid (GCF) of these
same subjects. In these subjects, a highly variable biphasic release profile
for chlorhexidine was demonstrated, with GCF levels 4 hours after chip insertion
(mean: 1444±783μg/mL), followed by a second peak at 72 hours (mean:
1902 ±1073 μg/mL). In a second study involving the insertion of 1
PerioChip under clinical conditions, the mean GCF level of chlorhexidine peaked
at 1088 ±678 μg/mL at 4 hours. The mean GCF levels then declined in
a highly erratic fashion to levels of 482 ±447 μg/mL at 72 hours without
producing a true second peak.
The results of these studies confirm a high degree of intersubject variability
in chlorhexidine release from the PerioChip matrix in vivo that was not seen
in vitro . Due to the nature and clinical use of the PerioChip dosage
form, dose proportionality was not and would not be expected to be demonstrated
between the two studies.
Clinical Studies
In two double-blind, randomized, controlled clinical trials, 447 adult patients
with periodontitis were entered who had at least 4 pockets with probing depth
of 5-8 mm that bled on probing. Patients studied were in good general health.
Diabetics were excluded from the studies. PerioChip was not studied in acutely
abscessed periodontal pockets. Patients were free of supragingival calculus
prior to baseline. In these two studies, the effects of scaling and root planing
(SRP) alone, and SRP followed by PerioChip treatment, were compared. All patients
received full mouth SRP at baseline. If the pocket depth remained ≥ 5 mm
at 3 and/or 6 months after initial treatment, another chip was placed into the
pocket. Teeth treated with PerioChip were found to have significantly reduced
probing pocket depth (PD) compared with those treated with SRP alone at 9 months
after initial treatment, as shown in Table 1.
Table 1 : Probing pocket depth (PD) at baseline and reduction
in PD at 9 months from 2 five-center U.S. clinical trials (in mm, mean ±
SE)
| Time |
Study #94-002 |
Study #94-003 |
| SRP alone |
SRP + PerioChip |
SRP alone |
SRP + PerioChip |
| PD at Baseline |
5.69 ± 0.58
(n = 107) |
5.79 ± 0.61
(n = 108) |
5.56 ± 0.54
(n = 115) |
5.67 ± 0.56
(n = 117) |
| PD Reduction at 9 months |
0.78 ± 0.07
(n = 101) |
1.06 ± 0.07*
(n = 101) |
0.52 ± 0.07
(n=107) |
0.84 ± 0.08**
(n = 110) |
SE = standard error; SRP = Scaling and Root
Planing
Significantly different from SRP alone: *(p = 0.006); **(p=0.001) |
PerioChip treatment resulted in a greater percentage of pockets and patients
that showed an improvement in PD of 2 mm or more compared with SRP alone at
9 months, as shown in Table 2. The differences in improvement were statistically
significant when analyzed on a per patient basis (p < 0.005). PerioChip treatment
maintained probing attachment level (PAL) compared with baseline or with SRP
alone at 9 months. The effects of PerioChip on bleeding upon probing have not
been established. In the two studies, there were no significant changes in plaque
development or gingivitis. Smokers and non-smokers were enrolled in these studies;
although non-smokers using PerioChip demonstrated significant improvement in
PD, smokers demonstrated a trend towards improvement that did not reach statistical
significance. This finding is consistent with the consensus that smoking is
a risk factor in periodontal diseases.
Table 2 : Number (percentage) of pockets and patients with
an improvement in PD ≥ 2 mm at 9 months from 2 five-center U.S. clinical
trials
| |
Study # 94-002 |
Study # 94-003 |
| SRP alone |
SRP + PerioChip |
SRP alone |
SRP + PerioChip |
| Pockets |
21/202
(11%) |
44/202
(22%) |
12/214
(6%) |
36/220
(16%) |
| Patients (one or both sites) |
17/101
(17%) |
36/101
(36%) |
11/107
(10%) |
28/110
(25%) |
In the two clinical studies above and an additional study (619 patients), the
adverse effects of tooth staining or altered taste perception were not reported
after the use of PerioChip.
Last updated on RxList: 3/4/2010