Evaluation of the PerioChip

Periodontal Specialist Local Drug Delivery for the treatment of periodontitis is again being revisited and this time it is by Chlorhexidine. No other product has been approved for this use since Actisite. In 1998, The FDA granted approval for The PerioChip which is marketed by Astra, Inc..

This product is generating a lot of interest.  New innovations are always exciting, especially if they perform in a manner consistent with all the hype.  Unfortunately, many do not.  I have received so many calls from dental colleagues asking what I thought of the PerioChip. .  The answer is ......
 
Each chip contains 2.5 mg of chlorhexidine in a biodegradable matrix of hydrolyzed gelatin.   The chip measures 4 x 5 x 1 mm.  It is supposed to be placed into a periodontal pocket following root planing.  The chip slowly dissolves by a hydrolysis reaction and should be completely gone in 10 days.  The bulk of the chlorhexidine 40 % is released within 24 hours and the balance over the remaining life of the chip.  Therefore, you do not have to bring the patient back for follow-up (however, follow-up is usually beneficial in patients with periodontitis so that proper oral hygiene can be reinforced).

  The chips are sold in boxes of ten for $160.00.  If you buy in quantity, the unit cost comes down.  One chip is good for one pocket.  If you have a tooth with pocketing on three surfaces, you will need three chips.  The manufacturer does not advise trying to cut the chip because you will reduce the total dose of chlorhexidine released into the pocket.  The improvements seen are dose dependent.

Let's take a look at this product and evaluate it's clinical performance compared to Actisite when placed  into a periodontal pocket combined with scaling and root planing as compared to scaling and root planing alone.  To do this, we have to examine the literature behind each treatment mode.

I have prepared the following three tables from the results shown in pertinent studies with respect to reduction in pocket depth and bleeding upon probing and the gain in clinical attachment levels.

Three landmark studies investigating local drug delivery vs. root planing were done by Newman, et al, J. Perio 65:685, 1994 and Drisco, et al, J Perio, 1995 for tetracycline fibers.  Solskone, et al, J Perio, 68:32, 1997 reported on chlorhexidine chips. 

Legend: All measurements are reported in millimeters. RP=root planing alone,  RP/LD=root planing with local drug delivery, Diff=the difference between the two treatment groups, @= approximate measurement taken from data plots in the publication (the actual numeric data was not specified).

Pocket Depths

   

Bleeding Upon Probing

 

Gain in Clinical Attachment Level

  

As you can see the reported numbers findings for the three treatment modalities are very similar.  In the Newman study and also in the Solskone study, local drug delivery generated improvements for the three parameters which were claimed to be statistically significant. The findings in the Drisco study were that fibers with root planing were not statistically better than root planing alone.

My interpretation of these results is as follows:  I have to question how significant is a statistically significant improvement in clinical attachment level of 0.48 mm in the Newman study and 0.16 mm in the Solskone study?  Are the findings significant in a clinical sense?  The American Academy of Periodontology wrote in a statement to all AAP members, "The magnitude of these changes are very small.  Furthermore, it should be noted that these are limited alterations in patients with advanced periodontitis."  In my opinion, local drug delivery has a long way to go to generate results that  are clinically significant.

Do the results hold up over time?  Longer term studies of the chip need to be done to answer these questions.  If you extrapolate the results from longer term Actisite studies, assuming that chip treated sites will respond like the Actisite sites, then we can expect a slow reopening of the pocket.  The reason for this trend has nothing to do with the local drug delivery system.  It is very simply due to our clinical limitations in closed root debridement.

Numerous studies have shown that as the pocket depth increases, our ability to thoroughly debride the root decreases.  Most clinicians would be surprised to find that most pockets of 5 mm or more have residual calculus following root planing.  Additionally, root anomalies, such as root flutes, developmental grooves, furcation invasions and enamel projections further diminish our debridement efficacy.  These nidus' of subgingival plaque gradually repopulate the immediate area of the sulcus and cause the pocket to  reform.

No studies have been published to date which investigate the efficacy of the chip in the following circumstances: localized juvenile periodontitis, rapidly progressive periodontitis, furcation lesions and intrabony defects.

In summary, I would propose the following guidelines:

1. you should expect results only comparable to Actisite.
2. You should use the chip in refractory sites (i.e.,  those which have not responded to root planing alone after you have allowed a sufficient time period to reevaluate the site).
3.  You should avoid trying them in pockets greater than 7 mm or sites with root anomalies and furcation lesions.  Using them in areas of simple root morphology will result in improved results.