The antibacterial activities of a homologous series (C8-C18) of alkylbenzyldimethylammonium cholorides (ABDAC) against Pseudomonas aeruginosa have been measured using both a minimum inhibitory concentration (MIC) procedure and a sterilization kinetics test carried out in deionized water. There was a log-linear relationship between activity measured by kinetics and carbon number. With MIC there was a log-linear relationship up to C14, when there was a turndown in activity. Consideration of the colloidal association of ABDAC in deionized water and in a simple salts growth media leads us to suggest that use of high concentrations of nutrient salts in MIC tests will lower the effective concentration of the surface active agents. This change may be responsible for the turndown in activity observed in MIC tests, and that in such circumstances the MIC test does not give a true reflection of the intrinsic activity of the compounds. Literature reports of parabolic relationships between ABDAC alkyl chain length and antimicrobial activity are reinterpreted on this basis.

Benzalkonium Compounds↗

PubMed1977

A comparison of tooth accumulated materials from quadrants treated surgically or nonsurgically.

The objective of this study was to test the validity of the clinical concept that periodontal surgery is beneficial in aiding the patient to reduce the amount of tooth accumulated materials in moderate to advanced cases of periodontal disease. Twelve arches in eight patients with moderate to severe bone loss were selected for this investigation. Using a split-mouth technique, 12 quadrants were subjected to pocket elimination by the use of osseous and soft tissue recontouring, and 12 quadrants received thorough deep scaling, root planing, and polishing. These patients were seen at 1,2, and 4 weeks after surgery for root planing and more oral hygiene instructions. At 6 weeks they received a prophylaxis, including root planing if indicated, throughout the mouth. The patients returned in 2 weeks, at which time plaque accumulations were then removed and collected by quadrant to be subjected to analysis using wet weights, dry weights and ash weights. The quantity of tooth accumulated debris on the surgically-treated quadrants was significantly greater than on those treated nonsurgically, as determined by the wet weight (P less than 0.01) and dry weight (P less than 0.05). There was, however, no significant difference with ash weight comparisons. The dry weight was the more accurate indicator of tooth accumulated materials. The mean ash weight on the surgically-treated mandibular quadrants (2.21 mg) was significantly greater (P less than 0.05) than from those treated nonsurgically (1.35 mg). The investigators' hypothesis that there would be more accretions on the side not involved in osseous surgery and pocket eradication was not supported in this study. Several possible reasons for this were elucidated and discussed.

Dental Deposits↗

PubMed1976