Tissue-dissolving capacity and antibacterial effect of buffered and unbuffered hypochlorite solutions.
OBJECTIVE
The goal of this study was to compare the dissolving potential of Dakin's solution with that of equivalent buffered and unbuffered sodium hypochlorite solutions on fresh and decayed tissues. In addition, the antimicrobial effect of Dakin's solution and equivalent unbuffered hypochlorite was tested.


METHODS
Tissue specimens were obtained from freshly dissected pig palates. Unbuffered 2.5% and 0.5% sodium hypochlorite solutions and 0.5% solutions buffered at a pH of 12 and a pH of 9 (Dakin's solution) were tested on fresh and decayed tissue. Tissue decay was assessed histologically. Antimicrobial testing was performed with Enterococcus faecalis in dentin blocks and on filter papers.


RESULTS
The 2.5% NaOCl solution was substantially more effective than the three 0.5% solutions in dissolving the test tissues. Buffering had little effect on tissue dissolution, and Dakin's solution was equally effective on decayed and fresh tissues. No differences were recorded for the antibacterial properties of Dakin's solution and an equivalent unbuffered hypochlorite solution.


CONCLUSIONS
In contrast to earlier statements, the results of this study do not demonstrate any benefit from buffering sodium hypochlorite with sodium bicarbonate according to Dakin's method. An irrigation solution with less dissolving potential may be obtained by simply diluting stock solutions of NaOCl with water.
Zehnder
Matthias
M
Department of Preventive Dentistry, Cariology, and Periodontology, Center for Dental Medicine, University of Zürich, Switzerland. zehnder@zzmk.unizh.ch
Kosicki
Daniel
D
Luder
Hansueli
H
Sener
Beatrice
B
Waltimo
Tuomas
T
D000704:Analysis of Variance; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D002021:Buffers; D004338:Drug Combinations; D013293:Enterococcus faecalis / Q000187:drug effects; D009061:Mouth Mucosa / Q000187:drug effects; D012388:Root Canal Irrigants / Q000737:chemistry / Q000494:pharmacology*; D017693:Sodium Bicarbonate / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000494:pharmacology*; D013552:Swine
D000891:Anti-Infective Agents, Local; D002021:Buffers; D004338:Drug Combinations; D012388:Root Canal Irrigants; C069467:modified Dakin's solution; D017693:Sodium Bicarbonate; D012973:Sodium Hypochlorite