Treatment paradigms in periodontal disease

The prevailing treatment paradigm in periodontal disease relies on debriding the tooth surfaces to keep the bacterial load below the level that triggers tissue loss. When debridement cannot be easily accomplished because of deep pocketing, access surgery is recommended. The debridement approach that involves access surgery is successful in 80% to 85% of patients. Patients who do not respond are often treated with systemic antibiotics. This paradigm, which is based on the nonspecific plaque hypothesis, is labor-intensive and relies on antibiotics only as a last resort. This nonspecific treatment paradigm is in contrast with the specific plaque hypothesis, which states that a limited number of bacterial species are specifically involved in most forms of periodontal disease. Some studies have significantly associated anaerobic bacteria with advanced forms of periodontal disease. These observations led us to hypothesize that most forms of periodontal disease are anaerobic infections, which can be treated by antimicrobials such as metronidazole or clindamycin. Three double-blind studies have shown that 1 to 2 weeks of unsupervised use of metronidazole-plus-debridement was significantly better than placebo-plus-debridement in reducing the need for periodontal surgery. These findings suggest that treatments based on the specific plaque hypothesis give clinicians and patients a choice regarding treatment options in periodontal disease.

Metronidazole in periodontitis V: debridement should precede medication

Two previous double-blind studies have shown that 1 week of metronidazole, plus scaling and root planing, can significantly reduce the number of teeth per patient that require periodontal surgery, when compared to a positive-control treatment that consisted of 1 week of placebo treatment plus scaling and root planing. The only difference between the two studies was that in one, metronidazole or placebo tablets were taken at the beginning of the debridement procedures, while in the other, the tablets were taken after all debridement was completed. This article describes the results obtained by combining the data from both studies and using an analysis of variance to identify the effects of medication and those of the study protocol. There was an average reduction in surgical needs of about 7.1 teeth per patient using metronidazole compared to 2.4 teeth in the positive-control group (P = 0.004). In the deep pockets, there was a significant protocol effect because there were additional improvements associated with using the medications after the debridement was completed.

The use of free gingival grafts in the treatment of peri-implant soft tissue complications: clinical report

Soft tissue complications including gingival hyperplasia, peri-implantitis, inadequate vestibular depth, and insufficient attached tissue may occur adjacent to endosseous implants. In most clinical cases vestibuloplasty and grafting techniques to establish a wider zone of keratinized tissue are not needed. A clinical case is presented involving peri-implant mucosal areas exhibiting persistent inflammation and progressive recession. A free gingival palatal graft was used to correct the soft tissue defects and provide optimal peri-implant health in order to increase the long-term prognosis of the implant reconstruction.

Metronidazole in periodontitis: reduced need for surgery

A considerable amount of circumstantial evidence indicates that most forms of periodontitis are due to the presence or dominance of a finite number of bacterial species in the subgingival plaque. Almost all of the putative pathogens are anaerobic species, indicating that most forms of periodontitis could be diagnosed as anaerobic infections. In this double-blind investigation, patients with elevated proportions or levels of spirochetes in 2 or more plaque samples, i.e., 60% spirochetes, were randomly assigned to receive either metronidazole, 250 mg 3 x a day for 1 week, or placebo (positive-control) after the completion of all debridement procedures. When the patients were re-examined 4 to 6 weeks later, the patients in the metronidazole group (n = 15) exhibited a highly significant (p less than 0.01) reduction in probing depth and apparent gain in attachment levels relative to the patients (n = 18) in the positive-control group about those teeth that initially had probing depths of 4 to 6 mm. This pattern was also observed about teeth that initially had probing depths greater than or equal to 7 mm. This reduction in probing depths and apparent gain in attachment was associated with a significant reduction in the need for periodontal surgery in the metronidazole-treated patients (difference 8.4 teeth per patient) compared to the positive-control patients (2.6 teeth per patient). These clinical improvements in the metronidazole group were associated with significantly lower proportions of spirochetes, selenomonads, motile rods, and P. intermedius, and a significantly higher proportion of cocci in the plaques. These findings indicate that systemic metronidazole, when given after all the root surface debridement is completed, leads to additional treatment benefits, including a reduced need for surgery, beyond that which can be achieved by debridement alone.

In vitro inhibition of lysosomal phospholipase A1 of rat lung by amiodarone and desethylamiodarone

Amiodarone causes phospholipid storage in the lysosomes of various types of lung cell in animals and man. It has been proposed that this is due to its ability to inhibit lysosomal phospholipase A. To investigate this further, a crude lysosomal fraction from rat lung was prepared and phospholipase A was isolated and its positional specificity was determined. Analysis of the products formed after incubation with 2-[1-14C]oleoylphosphatidylcholine showed that only phospholipase A1 activity is present. This soluble preparation of lung lysosomal phospholipase A1 was used to study inhibition by amiodarone and desethylamiodarone, in vitro. Both were extremely potent inhibitors of the lung acid phospholipase A1. To evaluate the levels of amiodarone in lung lysosomes, rats were treated with the agent for 3 days and the combined mitochondrial/lysosomal fraction of lung tissue was prepared by differential centrifugation. This fraction had been shown previously to be highly enriched in amiodarone. Purified mitochondria and lysosomes were isolated from the combined mitochondrial/lysosomal fraction with Percoll gradients and analyzed for their drug content by HPLC. Amiodarone and desethylamiodarone were present in roughly equal amounts, relative to protein, in mitochondria and lysosomes, respectively. Amiodarone appears to differ from other cationic amphiphilic drugs which cause lipidosis because the latter are more highly lysosomotropic. Although amiodarone does not appear to be highly lysosomotropic in lung, it causes lysosomal phospholipid storage because of its ability to concentrate in lung and because it inhibits lysosomal phospholipase A to a much greater extent than other cationic amphiphiles such as diethylaminoethoxyhexestrol, chloroquine and chlorphentermine.

Purification of lysosomal phospholipase A and demonstration of proteins that inhibit phospholipase A in a lysosomal fraction from rat kidney cortex

Phospholipase A has been isolated from a crude lysosomal fraction from rat kidney cortex and purified 7600-fold with a recovery of 9.8% of the starting activity. The purified enzyme is a glycoprotein having an isoelectric point of pH 5.4 and an apparent molecular weight of 30,000 by high-pressure liquid chromatography gel permeation. Naturally occurring inhibitors of lysosomal phospholipase A are present in two of the lysosomal-soluble protein fractions obtained in the purification. They inhibit hydrolysis of 1,2-di[1-14C]oleoylphosphatidylcholine by purified phospholipase A1 with IC50 values of 7-11 micrograms. The inhibition is abolished by preincubation with trypsin at 37 degrees C, but preincubation with trypsin at 4 degrees C has no effect, providing evidence that the inhibitors are proteins. The results suggest that the activity of lysosomal phospholipase A may be regulated in part by inhibitory proteins. Lysosomal phospholipase A from rat kidney hydrolyzes the sn-1 acyl group of phosphatidylcholine, does not require divalent cations for full activity, and is not inhibited by ethylenediaminetetraacetic acid. It has an acid pH optimum of 3.6-3.8. Neither p-bromophenacyl bromide, diisopropyl fluorophosphate, nor mercuric ion inhibits phospholipase A1. In contrast to rat liver, which has two major isoenzymes of acid phospholipase A1, kidney cortex has only one isoenzyme of lysosomal phospholipase A1.