Efficacy of Listerine®, Meridol® and chlorhexidine mouthrinses on plaque, gingivitis and plaque bacteria vitality -
M. Brecx, L. Netuschil, B. Reichert and G. Schreil Department of Conservative Dentistry, School of Dental Medicin"?, I'niversity of Tubingen, FRG
Brecx M, Netuschil L, Reicherl B and Schreil G: Efficacy of Listerine®, Meridol* and chlorhexidine mouthrinses on plaque, gingivitis and plaque bacteria vitality. J Clin Pcriodonlol 1990: 17: 292-297. Abstract. The experimental gingivitis model was used to compare the anti-plaque, anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listerine®) and an amine/stannous fluoride mouthwash (Meridol™), using a placebo preparation as negative control and a chlorhexidine solution as positive control in a double-blind study. After professional toothcleaning, 36 volunteers performed optitnal oral hygiene for a period of 2 weeks. They then ceased all oral hygiene procedures for 21 days during which they rinsed twice daily with 1 of the 4 mouthrinses. After 3 weeks of rinsing, plaque indices remained the lowest in the chlorhexidine group, while subjects using Listerine* or Meridol'* harbored similar indices significantly lower than that of individuals rinsing with the placebo solution. Up to that time, the gingival index scores were equal in all groups except for the chlorhexidine group in which the values only arnounted to half of these encountered in the other groups. The plaque vitality scores showed a bactericidal effect in vivo of chlorhexidine during the entire time of experimental gingivitis. In contrast, the data gave no evidence of an antibacterial effect in vivo of Listerine". The efficacy of Meridol"" to kill micro-organisms was similar to chlorhexidine during the early stages of plaque accumulation and, with time, became insignificant. This study has dernonstrated that chlorhexidine was superior to Listerine* and Meridol® in its ability to maintain low plaque scores and gingival health during this 3-week period of no mechanical oral hygiene. Moreover, it was also shown that Meridol® was as effective as Listerine* in reducing plaque accumulation and, in contrast to Listerine'", possessed a remarkable but transient antibacterial effect in vivo.
A clear cause and effect relationship exists between dental plaque and gingivitis (Loe et al. 1965, Theilade et al. 1966). For many years, chetnical agents in conjunction with or even instead of mechanical plaque control have been tested. Recently, the American Dental Association's Council of Dental Therapeutics has adopted "guidelines for acceptance of chemotherapeutic products for the control of supragingival dental plaque and gingivitis" (1985). Until now, only 2 agents have been accepted by this council: chlorhexidine and Listerine* (Mandel 1988). Chlorhexidine digluconate has been shown to provide the best microbiological and clinical benefits (for review, see Lang & Brecx (1986)).
The efficacy of Listerine* and chlorhexidine was cornpared in a study in which these mouthrinses were used as supplements to regular toothcleaning measures (Axelsson & Lindhe 1987). Under these circumstances, both mouthwash preparations improved the oral hygiene status as well as the gingival condition. In another study, during a 3-week period of no oral hygiene, the chlorhexidine solution was superior to Listerine* mouthwash in maintaining optimal gingival health (Siegrist et al. 1986). While in recent reviews (Overbolser 1988, Walker 1988), chlorhexidine and Listerine"-' were mentioned as irnportant antipiaque chemotherapeutics, no statetnents concering the efficacy of fiuoride
Key words: Listerine'*; Meridol""; chlorhexidine; dental plaque; experimental gingivitis; fluorescence microscopy; vitality test. Accepted for publication 21 May 1989
preparations were reported. Only few preparations are tnouthwashes, especially preparations containing stannous fluoride (Mandel 1988), amine fiuorides, or their combination (Saxer 1980). Using 2 stannous fiuoride mouthrinses twice daily during a 4-day period, Svatun et al. (1977) have reported an 80% reduction in the amount of plaque formed as compared to a placebo rinse, while an 88% reduction was observed when chlorhexidine was used. In 2 clinical trials of 5 days duration in which stannous fluoride mouthrinses were used, a reduction in plaque wet weight was shown although only a minimal prevention of gingivitis was noted (Tinanoff et al. 1980, Yankell et al. 1982). Relative to amine/stannous fiuo-
Listerine*, Meridol* & chlorhexidine rinses ride mouthwashes, only few data are available. When 250 ppm amine/stannous fluoride was used together with normal oral hygiene procedures over a period of 4 weeks, it reduced plaque scores and sulcus bleeding indices, albeit not as much as chlorhexidine (Albers et al. 1985). Similarly, Hefti & Huber (1987) in a 7-day test period found a significant reduction in plaque accumulation using a 410 ppm amine/stannous fluoride tnouthwash, although this solution was less effective than a 0.1% chlorhexidine mouthrinse. Until now, no clinical trials have been conducted to test the potential of these fluoride rinses as anti-plaque and anti-gingivitis agents in an experimental gingivitis model. The purpose of the present investigation was to compare the efficacy of Listerine* and an amine/stannous fluoride mouthrinse to control dental plaque and gingival inflamtnation during a 3week experitnental gingivitis trial, using a placebo solution as a negative control, and a chlorhexidine mouthwash as a positive control. The vitality of the remaining plaque bacteria was also assessed using a vital fluorescence technique after each mouthrinse.
293
Pll 2.01.8-
_—
-^
1.6•
\
1.4-
=1
1.2/
i.o0.8/
0.60.4-
"
n0 U.z
1
-^ -•-*• ^^
Placebo Listerine Meridol CHX
o
AA
0.0
0
7
14
.
21
days
Fig, 1, Mean Pll (-l-or —SD) at all time intervals for all treatment groups rinsing twice daily lor 1 min with 10 ml of placebo, Listerine'", Meridol"" or chlorhexidine.
Material and Methods
The 36 healthy volunteers were nondental students from the university of Tubingen. They were 13 females and 23 males ranging in age from 20 to 34 years. The reasons for this study were explained and consent forms signed by all participants. In the pretreatment phase, the individuals were subjected to a thorough prophylaxis and instructed in optimal mechanical plaque control. They then performed excellent toothcleatiing for a period of 2 weeks. At day 0, they were asked to refrain from all oral hygiene measures for a period of 21 days during which they rinsed twice daily for 1 min with 10 ml of one of the mouthwashes. Because of the doubleblind design, all solutions had the same colour and were kept in the same kind of bottle. At the end of the experimental gingivitis period, the various experimental groups appeared to be distributed as follows. Group P (/( = 9) rinsed with a 0.02% quinine-hydrochloride solution (Placebo). Group L (« = 9) rinsed with a phenolic compound (Listerine*). Group M («= 10) rinsed with a solu-
tion of 125 ppm F from amitie fluoride and 125 ppm F~ from stannous fluoride (Meridol*)Group C (/; = 8) rinsed with a solution containing 0.2% chlorhexidine digluconate (chlorhexidine). The periodontal status at time of selection as well as the age range of the individuals was very similar in all groups. Following these 21 days with mouthrinses but without mechanical plaque control, subjects resumed optimal mechanical toothcleaning. Clinical parameters were recorded at baseline (day 0) and after 7, 14 and 21 days without mechanical plaque control. Plaque accutnulation was assessed using the criteria of the plaque index (Pll) system (Silness & Loe 1964). The status of the gingiva was scored according to the criteria of the gingival index (GI) system (Loe & Silness 1963). Both indices were recorded on 4 surfaces (mesial, buccal, distal and lingual) of 28 teeth, excluding the wisdom teeth. Dental plaque for vital fluorescence (VF) examination was collected on days - 2 , 1, 7, 14 and 21 of the experiment.
Day —2 was selected in order to calculate the % of viable micro-organisms present in undisturbed plaque. Day 1 was the time of the subsequent sampling because a sufficient amount of plaque had to be present to permit the analysis (Netuschil et al. 1989). Plaque was each time sampled from the disto-buccal area of a first or second premolar with a sweep with the periodontal probe along the gingival margin, and placed on a glass slide. The solutions for the fluorescence analysis were prepared as described previously (Netuschil 1983, Netuschil et al. 1989). Plaque was stained by fluoresceindiacetate which gave a green color to the living micro-organistns, and by ethidiumbromide which introduced a red color into the nucleic acids of the dead bacteria. The samples were examined by 2 investigators, the intra- and inter-individual variations always remaining below 5% (0 I %). At a magnification of 312x, the samples were examined through a grid placed in one ocular. The grid was divided in 25 small squares. It was moved 4 times in a cross direction from the first central
294
Brecx el al.
area used for reading, which gave a total of 125 small squares analysed for each sample. In each small square, the rating was made as follows: : 0-20%; —: 20-40%; + - : 40-60%; +: 60-80%; + +: 80-100% of cell vitality. The mean of all these 125%s was taken as the representative % of cell vitality for that particular sample. Small squares without plaque were not taken into consideration. Furthermore, on a few occasions, the amount of plaque was too low to allov/ analysis of the sample. The clinical as well as the microscopic data were submitted to the KruskalWallis test for analysis of the differences between the various groups, the MannWhitney [/-test for unpaired data to compare the 4 mouthrinses at days 0, 7, 14 and 21, and the Wilcoxon signed rank test for the comparison of the data from each solution longitudinally.
GI 1.01
0.8-
0.6
0.4-
Plahebo Listerine Meridol CHX
0.2-
Results
Mean PlI scores increased rapidly between day 0 and day 7 in the placebo, Listerine® and Meridol® groups to 1.30-1.47 and only slightly thereafter (Fig. 1). After 21 days of plaque accumulation, the mean PlI scores were 1.80 for the placebo group and 1.44 and 1.46 for the Listerine* and Meridol® groups, respectively. Only at the end of the experiment did both groups show a significant (P
M. Brecx, L. Netuschil, B. Reichert and G. Schreil Department of Conservative Dentistry, School of Dental Medicin"?, I'niversity of Tubingen, FRG
Brecx M, Netuschil L, Reicherl B and Schreil G: Efficacy of Listerine®, Meridol* and chlorhexidine mouthrinses on plaque, gingivitis and plaque bacteria vitality. J Clin Pcriodonlol 1990: 17: 292-297. Abstract. The experimental gingivitis model was used to compare the anti-plaque, anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listerine®) and an amine/stannous fluoride mouthwash (Meridol™), using a placebo preparation as negative control and a chlorhexidine solution as positive control in a double-blind study. After professional toothcleaning, 36 volunteers performed optitnal oral hygiene for a period of 2 weeks. They then ceased all oral hygiene procedures for 21 days during which they rinsed twice daily with 1 of the 4 mouthrinses. After 3 weeks of rinsing, plaque indices remained the lowest in the chlorhexidine group, while subjects using Listerine* or Meridol'* harbored similar indices significantly lower than that of individuals rinsing with the placebo solution. Up to that time, the gingival index scores were equal in all groups except for the chlorhexidine group in which the values only arnounted to half of these encountered in the other groups. The plaque vitality scores showed a bactericidal effect in vivo of chlorhexidine during the entire time of experimental gingivitis. In contrast, the data gave no evidence of an antibacterial effect in vivo of Listerine". The efficacy of Meridol"" to kill micro-organisms was similar to chlorhexidine during the early stages of plaque accumulation and, with time, became insignificant. This study has dernonstrated that chlorhexidine was superior to Listerine* and Meridol® in its ability to maintain low plaque scores and gingival health during this 3-week period of no mechanical oral hygiene. Moreover, it was also shown that Meridol® was as effective as Listerine* in reducing plaque accumulation and, in contrast to Listerine'", possessed a remarkable but transient antibacterial effect in vivo.
A clear cause and effect relationship exists between dental plaque and gingivitis (Loe et al. 1965, Theilade et al. 1966). For many years, chetnical agents in conjunction with or even instead of mechanical plaque control have been tested. Recently, the American Dental Association's Council of Dental Therapeutics has adopted "guidelines for acceptance of chemotherapeutic products for the control of supragingival dental plaque and gingivitis" (1985). Until now, only 2 agents have been accepted by this council: chlorhexidine and Listerine* (Mandel 1988). Chlorhexidine digluconate has been shown to provide the best microbiological and clinical benefits (for review, see Lang & Brecx (1986)).
The efficacy of Listerine* and chlorhexidine was cornpared in a study in which these mouthrinses were used as supplements to regular toothcleaning measures (Axelsson & Lindhe 1987). Under these circumstances, both mouthwash preparations improved the oral hygiene status as well as the gingival condition. In another study, during a 3-week period of no oral hygiene, the chlorhexidine solution was superior to Listerine* mouthwash in maintaining optimal gingival health (Siegrist et al. 1986). While in recent reviews (Overbolser 1988, Walker 1988), chlorhexidine and Listerine"-' were mentioned as irnportant antipiaque chemotherapeutics, no statetnents concering the efficacy of fiuoride
Key words: Listerine'*; Meridol""; chlorhexidine; dental plaque; experimental gingivitis; fluorescence microscopy; vitality test. Accepted for publication 21 May 1989
preparations were reported. Only few preparations are tnouthwashes, especially preparations containing stannous fluoride (Mandel 1988), amine fiuorides, or their combination (Saxer 1980). Using 2 stannous fiuoride mouthrinses twice daily during a 4-day period, Svatun et al. (1977) have reported an 80% reduction in the amount of plaque formed as compared to a placebo rinse, while an 88% reduction was observed when chlorhexidine was used. In 2 clinical trials of 5 days duration in which stannous fluoride mouthrinses were used, a reduction in plaque wet weight was shown although only a minimal prevention of gingivitis was noted (Tinanoff et al. 1980, Yankell et al. 1982). Relative to amine/stannous fiuo-
Listerine*, Meridol* & chlorhexidine rinses ride mouthwashes, only few data are available. When 250 ppm amine/stannous fluoride was used together with normal oral hygiene procedures over a period of 4 weeks, it reduced plaque scores and sulcus bleeding indices, albeit not as much as chlorhexidine (Albers et al. 1985). Similarly, Hefti & Huber (1987) in a 7-day test period found a significant reduction in plaque accumulation using a 410 ppm amine/stannous fluoride tnouthwash, although this solution was less effective than a 0.1% chlorhexidine mouthrinse. Until now, no clinical trials have been conducted to test the potential of these fluoride rinses as anti-plaque and anti-gingivitis agents in an experimental gingivitis model. The purpose of the present investigation was to compare the efficacy of Listerine* and an amine/stannous fluoride mouthrinse to control dental plaque and gingival inflamtnation during a 3week experitnental gingivitis trial, using a placebo solution as a negative control, and a chlorhexidine mouthwash as a positive control. The vitality of the remaining plaque bacteria was also assessed using a vital fluorescence technique after each mouthrinse.
293
Pll 2.01.8-
_—
-^
1.6•
\
1.4-
=1
1.2/
i.o0.8/
0.60.4-
"
n0 U.z
1
-^ -•-*• ^^
Placebo Listerine Meridol CHX
o
AA
0.0
0
7
14
.
21
days
Fig, 1, Mean Pll (-l-or —SD) at all time intervals for all treatment groups rinsing twice daily lor 1 min with 10 ml of placebo, Listerine'", Meridol"" or chlorhexidine.
Material and Methods
The 36 healthy volunteers were nondental students from the university of Tubingen. They were 13 females and 23 males ranging in age from 20 to 34 years. The reasons for this study were explained and consent forms signed by all participants. In the pretreatment phase, the individuals were subjected to a thorough prophylaxis and instructed in optimal mechanical plaque control. They then performed excellent toothcleatiing for a period of 2 weeks. At day 0, they were asked to refrain from all oral hygiene measures for a period of 21 days during which they rinsed twice daily for 1 min with 10 ml of one of the mouthwashes. Because of the doubleblind design, all solutions had the same colour and were kept in the same kind of bottle. At the end of the experimental gingivitis period, the various experimental groups appeared to be distributed as follows. Group P (/( = 9) rinsed with a 0.02% quinine-hydrochloride solution (Placebo). Group L (« = 9) rinsed with a phenolic compound (Listerine*). Group M («= 10) rinsed with a solu-
tion of 125 ppm F from amitie fluoride and 125 ppm F~ from stannous fluoride (Meridol*)Group C (/; = 8) rinsed with a solution containing 0.2% chlorhexidine digluconate (chlorhexidine). The periodontal status at time of selection as well as the age range of the individuals was very similar in all groups. Following these 21 days with mouthrinses but without mechanical plaque control, subjects resumed optimal mechanical toothcleaning. Clinical parameters were recorded at baseline (day 0) and after 7, 14 and 21 days without mechanical plaque control. Plaque accutnulation was assessed using the criteria of the plaque index (Pll) system (Silness & Loe 1964). The status of the gingiva was scored according to the criteria of the gingival index (GI) system (Loe & Silness 1963). Both indices were recorded on 4 surfaces (mesial, buccal, distal and lingual) of 28 teeth, excluding the wisdom teeth. Dental plaque for vital fluorescence (VF) examination was collected on days - 2 , 1, 7, 14 and 21 of the experiment.
Day —2 was selected in order to calculate the % of viable micro-organisms present in undisturbed plaque. Day 1 was the time of the subsequent sampling because a sufficient amount of plaque had to be present to permit the analysis (Netuschil et al. 1989). Plaque was each time sampled from the disto-buccal area of a first or second premolar with a sweep with the periodontal probe along the gingival margin, and placed on a glass slide. The solutions for the fluorescence analysis were prepared as described previously (Netuschil 1983, Netuschil et al. 1989). Plaque was stained by fluoresceindiacetate which gave a green color to the living micro-organistns, and by ethidiumbromide which introduced a red color into the nucleic acids of the dead bacteria. The samples were examined by 2 investigators, the intra- and inter-individual variations always remaining below 5% (0 I %). At a magnification of 312x, the samples were examined through a grid placed in one ocular. The grid was divided in 25 small squares. It was moved 4 times in a cross direction from the first central
294
Brecx el al.
area used for reading, which gave a total of 125 small squares analysed for each sample. In each small square, the rating was made as follows: : 0-20%; —: 20-40%; + - : 40-60%; +: 60-80%; + +: 80-100% of cell vitality. The mean of all these 125%s was taken as the representative % of cell vitality for that particular sample. Small squares without plaque were not taken into consideration. Furthermore, on a few occasions, the amount of plaque was too low to allov/ analysis of the sample. The clinical as well as the microscopic data were submitted to the KruskalWallis test for analysis of the differences between the various groups, the MannWhitney [/-test for unpaired data to compare the 4 mouthrinses at days 0, 7, 14 and 21, and the Wilcoxon signed rank test for the comparison of the data from each solution longitudinally.
GI 1.01
0.8-
0.6
0.4-
Plahebo Listerine Meridol CHX
0.2-
Results
Mean PlI scores increased rapidly between day 0 and day 7 in the placebo, Listerine® and Meridol® groups to 1.30-1.47 and only slightly thereafter (Fig. 1). After 21 days of plaque accumulation, the mean PlI scores were 1.80 for the placebo group and 1.44 and 1.46 for the Listerine* and Meridol® groups, respectively. Only at the end of the experiment did both groups show a significant (P
