A model for studying the effects of mouthrinses on cfe novo plaque formation
Per Ramberg\ Yasushi Furuichi\ Jan Lindhe' and Abdul GaHar' 'Department of Periodontology, Faculty of Dentistry, University of Gothenburg, Gothenburg, Sweden; ^Colgate-Palmofive Technology Center, Psscataway, New Jersey, USA
Ramberg P, Furuichi Y, Lindhe J and Gaffar A: A model for studying the effects of mouthrinses on de novo plaque formation. J Clirt Periodontol 1992; 19: 509-520. Abstract. The aim of the present study was to describe a 4-day no oral hygiene model to assess the pattern of de novo plaque formation and to use this model to appraise the potential of some mouthwash preparations to retard or inhibit plaque formation in the human dentition, 10 subjects were recruited for the trial. During a preparatory period, the participants were exposed to repeated professional plaque control and given oral hygiene instruction to eliminate signs of gingivitis. At the end of the preparatory period, each participant received a final professional tooth cleaning and was subsequently told to abstain from mechanical plaque control efforts for the next 4 days. They were asked to rinse twice daily for 60 s with 10 ml varying test solutions. On Day 4. the volunteers were exposed to a new clinical examination and the presence and amount of plaque were examined by the use of the plaque index system (Pll), The participants were subsequently given a professional tooth cleaning and asked to exercise proper self performed plaque controi during the next 10 days, A new test period was then initiated, 6 different mouthwash preparations were tested in each subject namely. (1) placebo (a negative control rinse). (2) Veadent* mouthrinse. (3) Listerine* mouthnnse. (4) 0,06% triclosan + polyvinyl phosphonic acid (PVPA). (5) 0,06% triclosan + phenolic flavor and (6) 0,12% chJorhexidine digluconate (a positive control rinse). The results from the study revealed that the mean Pll values for individuals, groups of teeth and tooth surfaces provide an adequate but gross overall estimation of the potential of a given mouthrinse to retard / inhibit plaque build up. More detailed information on the effects of the test rinses could be obtained by data describing the % distribution of different Pll score categories; a high frequency of score 0 describes the potential of a mouthrinse to mamtain tooth surfaces free from plaque while a low frequency of score 2/3 describes the abihty of a treatment to retard/prevent gross plaque formation. The plaque pattern displays fmally allowed assessment of the magnitude of plaque prevention, in comparison to the positive and negative controls, that could be achieved by a given compound in various parts and surfaces of the dentition. In this model, all test rinses (i) were significantly more effective than the placebo rinse in retarding de novo plaque build up and (ii) had a minor effects on plaque build up in the maxillary molars and at the approximal surfaces. The chlorhexidine rinse was more effective than the other mouthwash preparations tested (except the mouthrinse containing triclosan and phenolic flavor) in all parts of the dentition. Both the Veadent® and the Listerine® mouthrinses were significantly less effective than the chlorhexidine rinse. The triclosan 4-PVPA containing mouthrinse was less effective than the chlorhexidine rinse in the molars and at the buccal tooth stirfaces. The triclosan + "phenolic flavor" containing mouthrinse had the same magnitude of efficacy as the chlorhexidine rinse in all parts of the dentition.
Proper plaque control is a key factor in the prevention of dental disease (Loda! et al, 1961, Suomi et al, 1971, Axelsson et al, 199]), Acceptable plaque control by mechanical means is difficult to achieve for most individuals and there-
fore chemical, incorporated in mouthwash or dentifrice preparations, have been used as supplements to traditional oral hygiene procedures. Among such compotmds antimicrobials such as chlorhexidine, phenolics, sanguinarine
Key words: antimicrobials: clinical trial: dental plaque: prevention Accepted for publication 18 August 1991
and triclosan have shown antiplaque effects when tested both in vitro and in vivo (for review. Parsons (1974), Loesche (1976), Hull (1980), Addy (1986), Kornman (1986), Mandel (1988)), An adjuvant to traditional oral hy-
510
Ramberg et al.
giene should ideally have an effect in parts of the oral cavity where mechanical procedures fail, i,e, the posterior parts of the dentition and at the approximal tooth surfaces (Lovdal et al, 1961, Cumming & Loe 1973, Axeisson & Lindhe 1978, Okamoto et al, 1988), Limited information, however, exists regarding the potential of chemical adjuvants to reach such parts of the human dentition. In a previous study from our laboratory the pattern of de novo plaque formation was monitored during a 2-week period of no oral hygiene. Plaque was assessed by the use of the plaque index system (Silness & Loe 1964) after I. 4, 7 and 14 days of no mechanical tooth cleaning. It was observed that most plaque formed (i) during the first 4 days, {ii) in the maxillary molar region, (iii) at approximal tooth surfaces and that (iv) differences between groups of teeth and tooth surfaces with respect to plaque scores observed at 4 days persisted at the 14 day examination. The first objective of the present study was to use a 4-day no oral hygiene model to study de novo plaque formation in various parts of the dentition. The second objective was to use this model to examine the potential of various antibacterial mouthrinses to retard or inhibit de novo plaque formation on various tooth surfaces. In this model 2 control rinses, one positive and one negative, were used to identify the relative efficacy of the mouthwash preparations tested. Material and Methods Experimental design
10 subjects aged 24—40 years (mean 29,5 years) were recruited for the trial. They were all free from signs of destructive periodontal disease and had not been on systemic antibiotic therapy during the 6 months preceding this study. During a preparatory period of 2 weeks, the participants were exposed to professional plaque control measures (Axeisson & Lindhe 1974) and. in addition, given repeated instruction in self performed plaque control measures. At the end of this preparatory period, each participant received a final professional tooth cleaning and was subsequentiy told to abstain from ali mechanical tooth cieaning efforts for of the next 4 days. They were asked to rinse, however, twice daiiy for 1 min each time, with 10 ml of a test solution. On Day
ALL SURFACES
Veadent
LIsterIng TRN'PVPA 0,12% CKX, TRNfPhen,
Fig. I. The mean individual Pli scores and the mean Pll scores for all tooth surfaces in the maxilla and in the mandible after 4 days of daily rinses with the various test solutions; mean standard deviation, TRN / PVPA = triclosan + polyvinyl phosphonic acids, TRN /phen = triclosan + phenolic flavor, ,J'; S,D,
4. the 10 subjects were exposed to a new ciinical examination. Immediately following this Day 4 examination, they were given professional tooth cleaning and again asked to exercise proper self performed plaque control measures. After a 10 day "wash-out" period the participants were given professional tooth cleaning after which an additional 4-day test period was initiated. This pattern was repeated for each of the 6 rinses, Mouthwash preparation
6 different mouthwash preparations were tested in the present study, (1) Placebo: 10% ethanol, 0,08% spearmint, 0,20% sorbitan, 0,01% sodium saccharine, 10% glycerin, 79,71% distilled water, (2) Veadent mouth rinse: Veadent*' (Vipont Lab, Inc, Fort Collins, Colorado, USA): 10% ethanol, 0,03% sanguinaria extract, 0,6% polysorbate 60, 0,2% zinc chloride, 0,10% Polox-
amer 407, 0,10% sodium saccharine, and 0,03% citric acid, 88,94"/., distilled water, Sanguinarine. a benzophenanthridine alkaloid obtained by alcoholic extraction of the bioodroot plant (Sanguinaria canadensis), has in recent years been used to controi dental plaque. Southard et al, (1984) in a 7-day parallel study reported (i) a 20% reduction in plaque scores compared to baseiine data in subjects who rinsed 5 times daily with a mouthrinse containing 0,03% sanguinaria extract and 0,2% zinc chloride as an adjuvant to daily brushing and (ii) a 19yo reduction in subjects who rinsed with a mouthrinse containing (0,045% sanguinaria extract without zinc chloride, Wennstrom & Lindhe (1985) in a 2week "experimental gingivitis trial" observed a 38% reduction in plaque scores and a 35% reduction in gingivitis scores after daily Veadent" rinsings (0,03yo sanguinaria extract and 0,2'!'CJ zinc chloride) compared to placebo treatment. In contrast, in 3 studies involving periods
Table I. The mean Pll for all surfaces and for the surfaces in the maxilla and in the mandible after each treatment; mean (standard deviation) and results of the Student- Newman-Keul test applied for the corresponding means; the solutions having different SNK groupings (letters) belonged to the different degree of efficacy on plaque formation All surfaces All teeth Solutions
mean (s,d,)
placebo Veadent Listerine TRN/PVPA 0,12% CHX, TRN/phen,
1,46 (0,12) 0,94(0,18) 0,88 (0,!6) 0,69 (016) 0,53 (0,17) 0,43 (0,11)
SNK grouping A B B C D D
Maxillary teeth
Mandibutar teeth
SNK mean (s,d,) grouping
SNK mean (s,d,) grouping
1,45 0,91 0,89 0,68 0,49 0,41
1,47 0,98 0,87 0,71 0,57 0,45
(0,14) (0,21) (0,22) (0,18) (0,18) (0,17)
A B B C D D
(0,23) (0,17) (0,13) (0,17) (0,19) (0,10)
A B BC CD DE
E
Mouthrirtses and plaque fornnation
MEAN PM - ALL SURFACES
Veadent
Lliteilne TRN/PVPA 0.1214 CHX. TRN/Phen.
511
MEAN PlI - ALL TEETH
Placebo
Veadent
Listerine rRN/PVPA 0.12% CHX. rRN/Phen.
Fig. 2. The mean PlI scores for various groups of teeth (Fig. 2A) and groups of tooth surfaces (Fig. 2B) on Day 4: TRN/PVPA = triciosan-Ipolyvinyl phosphonic acids. TRN/phen = triclosan + phenoIic flavor. Y. S.D.
of 4-19 days of no mechanical tooth cleaning, no pronounced efficacy of Viadent' was observed compared to the placebo rinsings (Siegrist et al. 1986. Etemadzdeh &. Ainamo 1987. Quir>nen et ai. 1990). Several investigations have reported on the effect of sanguinarine in retarding plaqtje and gingivitis when incorporated in dentifrices (Klewansky & Vernier 1984. Klewansky & Roth 1986. Lobene et al. 1986, Mauriello & Bader 1988) and combined with the use of mouthrinses which also contained sanguinarine (Greenfield & Cuchel 1984. Nygaard-Oestby & Persson 1984. Harper et al. 1990). (3) Listerine tnouthrinse: Listerine* (Warner Lambert Scandinavia AB., Solna, Sweden): 28.4% ethanol, 0.063% thymol. 0.091% eucalyptol. 0.042% menthol and 0.055% methyl salicylate.
Listerine*-. a mixture of the phenolrelated essential oils. th>Tnol and eucalyptol. mixed with menthol and methyl salicylate in a 26.9% hydroalcoholic vehicle. IS used as a mouthrinse. Several cross-over designed short-term "experimental gingivitis" model studies have demonstrated the efficacy of Listerine" in reducing plaque and gingivitis when used as a single plaque control measure. Thus, Lusk et al. (1974) reported in a cross-over 12-day study that 3 daily rinsings with Listerine' resulted in a 30?'o reduction in plaque score, a 79% reduction in gingivitis score compared to tap water rinsings. Fomeil et al. (1975) showed in a cross-over 2-week study that 3 daily rinses with Listerine* mouthwash resulted in a 50% reduction in plaque scores, a 93% reduction in plaque wet weight and a 47% reduction
Table 2. The mean PlI scores on Day 4 for the groups of teeth and tooth surfaces after 2 X daily uses of the mouthrinses: mean (standard deviation): the results of the Student.. Newman-Keul tests applied for the corresponding means Incisors and canines
Premoiars
Molars
Mouthrinses
SNK mean (s,d,) grouping
SNK mean (s.d.) grouping
SNK mean (s.d.) grouping
placebo Veadent Listerine TRN/PVPA 0,12% CHX TRN/phen.
1.45 0.77 0.70 0.56 0.44 0.29
1.48 (0.15) A 0.92(0.17) B 0,88 (0.19) B 0,65 (0.16) C 0.49 (0.18) CD 0.42 (0.12) D
1.47 (0.16) A 1.22 (0.18) B 1.14(0,24) BC 0,94(0.18) C 0.70 (0.17) D 0.64 (0,20) D
Approximal surfaces
Buccal surfaces
Lingual !surfaces
Mouthrinses
SNK mean (s.d.) grouping
SNK mean (s,d.) grouping
SNK mean (s,d,) grouping
placebo Veadent Listerine TRN/PVPA 0.12% CHX TRN/phen.
1.86(0.14) A 1.26(0.21) B 1,16(0.19) BC 1.00(0.19) C 0.75 (0.20) D 0.70 (0.19) D
1.51 0,87 0,82 0.49 0,39 0.21
0.64 (0.20) A 0,36(0.11) B 0.37 (0.15) BC 0.26 (0.18) BCD 0,18 (0.12) CD 0.12 (0.10) D
(0.18) A (0.25) B (0.19) BC (0.18) CD (0.23) DE (0.09) E
(0.19) A (0.29) B (0.26) B (0.23) C (0.24) CD (0,15) D
in gingivitis scores compared to placebo rinsings. Mankodi et al, (1987) reported in a parallel 2-week study that twice daily rinsings with Listerine * revealed a 45% reduction in plaque score and a 57% reduction in gingivitis score compared to placebo, 2 recently published parallel designed 3-week trials (Siegrist et al, 1986, Brecx et al. 1990) reported significantly less efficacy of Listerine® compared to a 0.2% chlorhexidine mouthrinse in preventing plaque formation and inhibiting the development of gingivitis. Several long-term studies have demonstrated a I9.5°/i>-5l% reduction in plaque scores and a 24%^51% in gingivitis scores when Listerine* was used as a supplement to mechanical plaque control (Lamster et al. 1983, Gordon et al. 1985. Axelsson & Lindhe 1987, DePaola et al. 1989. Overholser et al. 1990). (4) 0,06% triciosan, 3% (polyvinyl phosphonic acid (PVPA): 10% ethanol, S% Propylene glycol. 0.30';''o Sodium lauryl suifate. 0.02% sodium saccharine. 13.08% NaOH 2N. 68.54% Distilled water. (5) 0.06% triciosan. 0.25°/ii phenolic flavor: 23% ethanol. 0.26% Phenolic flavor, 0.50% Sodium lauryl suifate, 0.10% Benzoic acid, 76.08% Distilled water. Triciosan (2.4.4' trichloro-2' hydroxv diphenyl ether) is a nonionic antimicrobial compound widely used as a skindegerming agent. Marked effects on plaque and gingivitis were reported favoring the use of dentifrices containing triciosan and either zinc citrate (Svatun et al. 1987. Svatun et al, 1989, Stephen et al, 1990, Svatun et al. 1990) or polyvinylmethyl ether maleic acid (PVM/ MA) (Sigh et al. 1989. Palmo et al, 1989. Garcia-Goody et al. 1990). A few
512
Ramherg et al. MEAN PlI • MANDIBULAR TEETH
MEAN PlI - MAXILLARY TEETH
Placibo
V»dent
LisUrlne TRN/PVPA 0,12% CHX, TRN/Phan.
Placebo
Vsadent
LIsterlna TRN/PVPA 0,12% CHX, TRN/Phan,
Fig. 3. The mean PI] scores for various groups of teeth in the maxilla (Fig. 3A) and in the mandible (Fig, 3B) on Day 4; TRN/PVPA = triclosan + polyvinyl phosphonic acids, TRN/phen = triclosan + phenolic flavor, X: S,D, Studies have also been published on the effect of triclosan incorporated in mouthrinse preparations, Abello et al, (1990) in a cross-over no oral hygiene study, involving 20 subjects, reported that the 7-day use of a 0,03% triclosan and 0,25% PVM/'MA containing mouthrinse resulted in a 49,8% reduction in plaque scores compared to a placebo rinse, Jenkins et al, (1991) studied the effect of (1) tdciosan containing and (2) sodium lauryl sulphate (SLS) containing mouthwash preparations compared to (3) saline and (4) Corsodyl* (0,2°'(. chlorhexidine gluconate) mouthrinses in 16 subjects during a 4 day period of no mechanical tooth cleaning. They found that mouthrinses containing either 0,2% triclosan or 1% SLS reduced plaque formation significantly compared to saline, but were significantly less effective than Corsodyl*,
Chlorhexidine is a cationic bisbiguanide with a broad antimicrobial spectrum including gram-positive and gram-negative micro-organisms. The antipiaque/ antigingivitis efficacy of chlorhexidine either in a 0,12% or a 0,2% mouthrinse solution is well documented (e,g,, Loe & Rindom Schiatt 1970, Flotra etal, 1972, Loe et al, 1976, Lang et al, 1982, Segreto et al, 1986, Grossman et al, 1986, Banting et al. 1989, Overholser 1990), The rinse preparations were retained in identical but coded bottles. The 6-test solutions were tested in a randomized order. Neither the examiner nor the participants were aware of the content of the rinse used.
ence and amount of plaque was examined and scored by the use of the plaque index system fPlI; Silness & Loe 1964). Scores were obtained from all teeth except 3rd molars and from al) buccal, lingual, mesial, and distal surfaces. The scores from the 4 surfaces of a tooth were added and divided by 4 to give the mean PlI score for the tooth. The mean Pll scores for the individual subject (individual mean P!l) was obtained by adding the score values and dividing by the number of surfaces examined. The scores for groups of teeth and tooth surfaces were calculated to provide the mean PlI score for certain groups of teeth and tooth surfaces.
Clinicai examination
Statistlcai analysis
(6) 0.12% chlorhexidine digluconate solution: 10% ethanol, 0,08% spearmint, 0,2% sorbitan, 0,01% saccharine, 10% glycerine, 0,12% chlorhexidine digluconate, 79,07% distilled water.
All examinations were performed by one examiner (PR), The microbial tooth deposits were disclosed with topically applied erythrosin (Diaplaque, Walco AB, Skarholmen, Sweden), The pres-
The statistical analysis including the Student-Newman-Keul test (SNK-test) was applied with a 5% significance level. Separate analyses were made for the individual mean, for the mean for groups
MEAN Pll - MAXILLARY TEETH
Placebo
Vaadint
Llaterlne TRN/PVPA 0,12% CHX, TRN/Phan.
S
Placebo
MEANPII - MANDIBULAR TEETH
Vaadent
Llaterlna TRN/PVPA 0,12% CHX, TRN/Ptien,
Fig. 4. The mean Pll scores for various groups of tooth surfaces in the maxilla (Fig, 4A) and in the mandible (Fig, 4B) on Day 4; TRN/ PVPA = triclosan + polyvinyl phosphonic acids, TRN/phen = triclosan + phenoIic flavor, X; S,D.
Mouthrinses and plaque formation ALL TOOTH SURFACES < N=1096 )
100 %
• • ^ 0 • D
80
H1
60 40 20
ziBL
PEI SCORE 0
Results Mean PII scores
Placabo Vsadent Usierlne TRN^PVPA 0.12% CHX THN/Phen.
•
1 1 1 PII SCORE 2/3
Fig. i. The % distribution of the surfaces that belonged to PII score category 0 or 2/3 on Day 4; TRN/PVPA = triclosan + polyvinyl phosphonic acids, TRN/phen = triclosan + phenolic flavor. of teeth and tooth surfaces as well as for treatments. Mean PII score
The individual mean PII value for the 10 subjects was first calculated in order to assess the general potential of a given mouthrinses to prevent or retard de novo plaque formation. Comparisons were made with a positive (0.12% chlorhexidine digluconate) and a negative control (placebo) rinse. Subsequently the mean PII scores for different groups of teeth and tooth surfaces were calculated to examine, if the efficacy of the solution tested on de novo plaque formation differed in different parts of the dentition.
% distribution of PII score categories
The efficacy of the solutions tested on de novo plaque formation was further
assessed by analyzing the percentage distribution of surfaces that belonged to different PU score categories; score 0 and score 2 + 3. The number of surfaces that received PII score of 0 or 2 + 3, after each treatment were divided by the number of the surfaces examined to give the percentage of surfaces that belonged to either of these PII score categories. The frequency distribution of different PU score categories were made for all tooth surfaces as well as for groups of teeth and groups of tooth surfaces separately.
Pattern of plaque accumulation (plaque pattern display)
The purpose of this analysis was to illustrate the efficacy of the mouthrinse solutions on de novo plaque formation on each individual tooth surface.
MAXILLARY TOOTH SURFACES ( N=548 )
The mean individual PU scores for all surfaces and for the surfaces in the maxilla and in the mandible after each treatment are reported in Fig. 1 and Table 1. Table 1 also presents the results of the SNK tests. After 4 days of no mechanical tooth cleaning, the mean individual PII scores for all surfaces were 1.46 after placebo treatment (negative control) and 0.53 after 0.12% chlorhexidine treatment (positive control). The corresponding scores after Veadent*, Listerine^, triclosan + PVPA and triclosan+phenolic flavor treatments were 0.94, 0.88, 0,69 and 0.43, respectively (Fig. 1, Table 1). The statistical analysis (SNK tests) revealed that the Veadent^ and the Listerine* mouthwash preparations were more effective than placebo rinse to retard de novo plaque formation. It was also observed, however, that the triclosan + PVPA containing rinse was more effective than Veadent', Listerine* and that triclosan + phenolic flavor and the positive control were more effective than the other 4 preparations tested (Table 1). Thus, all test solutions examined received a significantly lower mean PII score than the placebo solution but, with one exception namely triciosan + phenohc fiavor, yielded a significantly higher mean PII score than the positive control rinse. It was also revealed that (Fig. 1) for a given treatment the mean PU score for the maxillary dentition did not differ from the corresponding score for the mandible. In other words, the amount of plaque formed in the maxilla appeared to be sitnilar to that formed in
MANDIBULAR TOOTTH SURFACES
100
D D
Pil SCORE 0
PII SCORE 2/3
513
PII SCORE 0
Placebo VeadenI Lcsterine TRN/PVPA 0.12% CHX TRN/Phen.
PII SCORE 2/3
f^ig. 6. The % distribution of surfaces that belonged to PII score category 0 or 2/3 in the maxilla (Fig. 6A) and mandible (Fig. 6B) on Day 4.
SI 4
Ramberg et al.
the mandible. The statistical analysis, however, indicated that differences with respect to plaque formation between the different mouthrinse preparations tested were more readily disclosed by individual mean PI! and the mean Pll scores for the maxilla than by the mean Pll scores for the mandible. The results from the analyses performed regarding the mean Pll scores for different groups of teeth and tooth surfaces are reported m Fig, 2 and in Table 2, For all solutions tested with the exception of placebo, it was observed that molars consistently received higher Pll scores than premolars. and premolars higher scores than anterior teeth. Furthermore lingual surfaces consistently received lower Pll scores than the buccal and approximal surfaces. From the results of the SNK tests (Table 2). it could be concluded that (i) all 4 test rinses after 4 days trial had resulted in significantly lower Pll scores than the negative control rinse at aii groups of teeth and tooth surfaces examined, (ii) the mean PIJ scores were significantly higher after Veadent" and Listerine' treatments than after the use of the positive control 0,12% chlorhexidine in all groups of teeth and tooth surfaces,
(except at the lingual surfaces after Listerine* treatment), (iii) there was no significant difference between Veadent* and Listerine' with respect to the mean Pll scores in any groups of teeth and tooth surfaces, (iv) the mean Pll scores for different groups of teeth and surfaces after triclosan-I-phenolic flavor treatment were similar to those obtained after treatment with the positive control, (v) in molars and at approxima! surfaces, the mean Pll scores after triclosan + PVPA treatment were significantly higher than the corresponding scores obtained after treatment with the positive control. The mean PU scores for the groups of teeth and tooth surfaces in the maxilla and in the mandible and for various treatments are presented in Figs, 3, 4. From the data reported it can be seen that the variation with respect to plaque accumulation at various groups of teeth was more pronounced in the maxillary than in the mandibular dentition (Fig, 3), It was also observed that the buccal surfaces of the maxillary teeth consistently accumulated more plaque than the corresponding surfaces in the mandible, while lingual (palatal) surfaces of the maxillary teeth accumulated small
THE PERCENTAGE OF THE SURFACES THAT RECEIVED SCORE 0 APPROXIUAL SURFACES ( n
Per Ramberg\ Yasushi Furuichi\ Jan Lindhe' and Abdul GaHar' 'Department of Periodontology, Faculty of Dentistry, University of Gothenburg, Gothenburg, Sweden; ^Colgate-Palmofive Technology Center, Psscataway, New Jersey, USA
Ramberg P, Furuichi Y, Lindhe J and Gaffar A: A model for studying the effects of mouthrinses on de novo plaque formation. J Clirt Periodontol 1992; 19: 509-520. Abstract. The aim of the present study was to describe a 4-day no oral hygiene model to assess the pattern of de novo plaque formation and to use this model to appraise the potential of some mouthwash preparations to retard or inhibit plaque formation in the human dentition, 10 subjects were recruited for the trial. During a preparatory period, the participants were exposed to repeated professional plaque control and given oral hygiene instruction to eliminate signs of gingivitis. At the end of the preparatory period, each participant received a final professional tooth cleaning and was subsequently told to abstain from mechanical plaque control efforts for the next 4 days. They were asked to rinse twice daily for 60 s with 10 ml varying test solutions. On Day 4. the volunteers were exposed to a new clinical examination and the presence and amount of plaque were examined by the use of the plaque index system (Pll), The participants were subsequently given a professional tooth cleaning and asked to exercise proper self performed plaque controi during the next 10 days, A new test period was then initiated, 6 different mouthwash preparations were tested in each subject namely. (1) placebo (a negative control rinse). (2) Veadent* mouthrinse. (3) Listerine* mouthnnse. (4) 0,06% triclosan + polyvinyl phosphonic acid (PVPA). (5) 0,06% triclosan + phenolic flavor and (6) 0,12% chJorhexidine digluconate (a positive control rinse). The results from the study revealed that the mean Pll values for individuals, groups of teeth and tooth surfaces provide an adequate but gross overall estimation of the potential of a given mouthrinse to retard / inhibit plaque build up. More detailed information on the effects of the test rinses could be obtained by data describing the % distribution of different Pll score categories; a high frequency of score 0 describes the potential of a mouthrinse to mamtain tooth surfaces free from plaque while a low frequency of score 2/3 describes the abihty of a treatment to retard/prevent gross plaque formation. The plaque pattern displays fmally allowed assessment of the magnitude of plaque prevention, in comparison to the positive and negative controls, that could be achieved by a given compound in various parts and surfaces of the dentition. In this model, all test rinses (i) were significantly more effective than the placebo rinse in retarding de novo plaque build up and (ii) had a minor effects on plaque build up in the maxillary molars and at the approximal surfaces. The chlorhexidine rinse was more effective than the other mouthwash preparations tested (except the mouthrinse containing triclosan and phenolic flavor) in all parts of the dentition. Both the Veadent® and the Listerine® mouthrinses were significantly less effective than the chlorhexidine rinse. The triclosan 4-PVPA containing mouthrinse was less effective than the chlorhexidine rinse in the molars and at the buccal tooth stirfaces. The triclosan + "phenolic flavor" containing mouthrinse had the same magnitude of efficacy as the chlorhexidine rinse in all parts of the dentition.
Proper plaque control is a key factor in the prevention of dental disease (Loda! et al, 1961, Suomi et al, 1971, Axelsson et al, 199]), Acceptable plaque control by mechanical means is difficult to achieve for most individuals and there-
fore chemical, incorporated in mouthwash or dentifrice preparations, have been used as supplements to traditional oral hygiene procedures. Among such compotmds antimicrobials such as chlorhexidine, phenolics, sanguinarine
Key words: antimicrobials: clinical trial: dental plaque: prevention Accepted for publication 18 August 1991
and triclosan have shown antiplaque effects when tested both in vitro and in vivo (for review. Parsons (1974), Loesche (1976), Hull (1980), Addy (1986), Kornman (1986), Mandel (1988)), An adjuvant to traditional oral hy-
510
Ramberg et al.
giene should ideally have an effect in parts of the oral cavity where mechanical procedures fail, i,e, the posterior parts of the dentition and at the approximal tooth surfaces (Lovdal et al, 1961, Cumming & Loe 1973, Axeisson & Lindhe 1978, Okamoto et al, 1988), Limited information, however, exists regarding the potential of chemical adjuvants to reach such parts of the human dentition. In a previous study from our laboratory the pattern of de novo plaque formation was monitored during a 2-week period of no oral hygiene. Plaque was assessed by the use of the plaque index system (Silness & Loe 1964) after I. 4, 7 and 14 days of no mechanical tooth cleaning. It was observed that most plaque formed (i) during the first 4 days, {ii) in the maxillary molar region, (iii) at approximal tooth surfaces and that (iv) differences between groups of teeth and tooth surfaces with respect to plaque scores observed at 4 days persisted at the 14 day examination. The first objective of the present study was to use a 4-day no oral hygiene model to study de novo plaque formation in various parts of the dentition. The second objective was to use this model to examine the potential of various antibacterial mouthrinses to retard or inhibit de novo plaque formation on various tooth surfaces. In this model 2 control rinses, one positive and one negative, were used to identify the relative efficacy of the mouthwash preparations tested. Material and Methods Experimental design
10 subjects aged 24—40 years (mean 29,5 years) were recruited for the trial. They were all free from signs of destructive periodontal disease and had not been on systemic antibiotic therapy during the 6 months preceding this study. During a preparatory period of 2 weeks, the participants were exposed to professional plaque control measures (Axeisson & Lindhe 1974) and. in addition, given repeated instruction in self performed plaque control measures. At the end of this preparatory period, each participant received a final professional tooth cleaning and was subsequentiy told to abstain from ali mechanical tooth cieaning efforts for of the next 4 days. They were asked to rinse, however, twice daiiy for 1 min each time, with 10 ml of a test solution. On Day
ALL SURFACES
Veadent
LIsterIng TRN'PVPA 0,12% CKX, TRNfPhen,
Fig. I. The mean individual Pli scores and the mean Pll scores for all tooth surfaces in the maxilla and in the mandible after 4 days of daily rinses with the various test solutions; mean standard deviation, TRN / PVPA = triclosan + polyvinyl phosphonic acids, TRN /phen = triclosan + phenolic flavor, ,J'; S,D,
4. the 10 subjects were exposed to a new ciinical examination. Immediately following this Day 4 examination, they were given professional tooth cleaning and again asked to exercise proper self performed plaque control measures. After a 10 day "wash-out" period the participants were given professional tooth cleaning after which an additional 4-day test period was initiated. This pattern was repeated for each of the 6 rinses, Mouthwash preparation
6 different mouthwash preparations were tested in the present study, (1) Placebo: 10% ethanol, 0,08% spearmint, 0,20% sorbitan, 0,01% sodium saccharine, 10% glycerin, 79,71% distilled water, (2) Veadent mouth rinse: Veadent*' (Vipont Lab, Inc, Fort Collins, Colorado, USA): 10% ethanol, 0,03% sanguinaria extract, 0,6% polysorbate 60, 0,2% zinc chloride, 0,10% Polox-
amer 407, 0,10% sodium saccharine, and 0,03% citric acid, 88,94"/., distilled water, Sanguinarine. a benzophenanthridine alkaloid obtained by alcoholic extraction of the bioodroot plant (Sanguinaria canadensis), has in recent years been used to controi dental plaque. Southard et al, (1984) in a 7-day parallel study reported (i) a 20% reduction in plaque scores compared to baseiine data in subjects who rinsed 5 times daily with a mouthrinse containing 0,03% sanguinaria extract and 0,2% zinc chloride as an adjuvant to daily brushing and (ii) a 19yo reduction in subjects who rinsed with a mouthrinse containing (0,045% sanguinaria extract without zinc chloride, Wennstrom & Lindhe (1985) in a 2week "experimental gingivitis trial" observed a 38% reduction in plaque scores and a 35% reduction in gingivitis scores after daily Veadent" rinsings (0,03yo sanguinaria extract and 0,2'!'CJ zinc chloride) compared to placebo treatment. In contrast, in 3 studies involving periods
Table I. The mean Pll for all surfaces and for the surfaces in the maxilla and in the mandible after each treatment; mean (standard deviation) and results of the Student- Newman-Keul test applied for the corresponding means; the solutions having different SNK groupings (letters) belonged to the different degree of efficacy on plaque formation All surfaces All teeth Solutions
mean (s,d,)
placebo Veadent Listerine TRN/PVPA 0,12% CHX, TRN/phen,
1,46 (0,12) 0,94(0,18) 0,88 (0,!6) 0,69 (016) 0,53 (0,17) 0,43 (0,11)
SNK grouping A B B C D D
Maxillary teeth
Mandibutar teeth
SNK mean (s,d,) grouping
SNK mean (s,d,) grouping
1,45 0,91 0,89 0,68 0,49 0,41
1,47 0,98 0,87 0,71 0,57 0,45
(0,14) (0,21) (0,22) (0,18) (0,18) (0,17)
A B B C D D
(0,23) (0,17) (0,13) (0,17) (0,19) (0,10)
A B BC CD DE
E
Mouthrirtses and plaque fornnation
MEAN PM - ALL SURFACES
Veadent
Lliteilne TRN/PVPA 0.1214 CHX. TRN/Phen.
511
MEAN PlI - ALL TEETH
Placebo
Veadent
Listerine rRN/PVPA 0.12% CHX. rRN/Phen.
Fig. 2. The mean PlI scores for various groups of teeth (Fig. 2A) and groups of tooth surfaces (Fig. 2B) on Day 4: TRN/PVPA = triciosan-Ipolyvinyl phosphonic acids. TRN/phen = triclosan + phenoIic flavor. Y. S.D.
of 4-19 days of no mechanical tooth cleaning, no pronounced efficacy of Viadent' was observed compared to the placebo rinsings (Siegrist et al. 1986. Etemadzdeh &. Ainamo 1987. Quir>nen et ai. 1990). Several investigations have reported on the effect of sanguinarine in retarding plaqtje and gingivitis when incorporated in dentifrices (Klewansky & Vernier 1984. Klewansky & Roth 1986. Lobene et al. 1986, Mauriello & Bader 1988) and combined with the use of mouthrinses which also contained sanguinarine (Greenfield & Cuchel 1984. Nygaard-Oestby & Persson 1984. Harper et al. 1990). (3) Listerine tnouthrinse: Listerine* (Warner Lambert Scandinavia AB., Solna, Sweden): 28.4% ethanol, 0.063% thymol. 0.091% eucalyptol. 0.042% menthol and 0.055% methyl salicylate.
Listerine*-. a mixture of the phenolrelated essential oils. th>Tnol and eucalyptol. mixed with menthol and methyl salicylate in a 26.9% hydroalcoholic vehicle. IS used as a mouthrinse. Several cross-over designed short-term "experimental gingivitis" model studies have demonstrated the efficacy of Listerine" in reducing plaque and gingivitis when used as a single plaque control measure. Thus, Lusk et al. (1974) reported in a cross-over 12-day study that 3 daily rinsings with Listerine' resulted in a 30?'o reduction in plaque score, a 79% reduction in gingivitis score compared to tap water rinsings. Fomeil et al. (1975) showed in a cross-over 2-week study that 3 daily rinses with Listerine* mouthwash resulted in a 50% reduction in plaque scores, a 93% reduction in plaque wet weight and a 47% reduction
Table 2. The mean PlI scores on Day 4 for the groups of teeth and tooth surfaces after 2 X daily uses of the mouthrinses: mean (standard deviation): the results of the Student.. Newman-Keul tests applied for the corresponding means Incisors and canines
Premoiars
Molars
Mouthrinses
SNK mean (s,d,) grouping
SNK mean (s.d.) grouping
SNK mean (s.d.) grouping
placebo Veadent Listerine TRN/PVPA 0,12% CHX TRN/phen.
1.45 0.77 0.70 0.56 0.44 0.29
1.48 (0.15) A 0.92(0.17) B 0,88 (0.19) B 0,65 (0.16) C 0.49 (0.18) CD 0.42 (0.12) D
1.47 (0.16) A 1.22 (0.18) B 1.14(0,24) BC 0,94(0.18) C 0.70 (0.17) D 0.64 (0,20) D
Approximal surfaces
Buccal surfaces
Lingual !surfaces
Mouthrinses
SNK mean (s.d.) grouping
SNK mean (s,d.) grouping
SNK mean (s,d,) grouping
placebo Veadent Listerine TRN/PVPA 0.12% CHX TRN/phen.
1.86(0.14) A 1.26(0.21) B 1,16(0.19) BC 1.00(0.19) C 0.75 (0.20) D 0.70 (0.19) D
1.51 0,87 0,82 0.49 0,39 0.21
0.64 (0.20) A 0,36(0.11) B 0.37 (0.15) BC 0.26 (0.18) BCD 0,18 (0.12) CD 0.12 (0.10) D
(0.18) A (0.25) B (0.19) BC (0.18) CD (0.23) DE (0.09) E
(0.19) A (0.29) B (0.26) B (0.23) C (0.24) CD (0,15) D
in gingivitis scores compared to placebo rinsings. Mankodi et al, (1987) reported in a parallel 2-week study that twice daily rinsings with Listerine * revealed a 45% reduction in plaque score and a 57% reduction in gingivitis score compared to placebo, 2 recently published parallel designed 3-week trials (Siegrist et al, 1986, Brecx et al. 1990) reported significantly less efficacy of Listerine® compared to a 0.2% chlorhexidine mouthrinse in preventing plaque formation and inhibiting the development of gingivitis. Several long-term studies have demonstrated a I9.5°/i>-5l% reduction in plaque scores and a 24%^51% in gingivitis scores when Listerine* was used as a supplement to mechanical plaque control (Lamster et al. 1983, Gordon et al. 1985. Axelsson & Lindhe 1987, DePaola et al. 1989. Overholser et al. 1990). (4) 0,06% triciosan, 3% (polyvinyl phosphonic acid (PVPA): 10% ethanol, S% Propylene glycol. 0.30';''o Sodium lauryl suifate. 0.02% sodium saccharine. 13.08% NaOH 2N. 68.54% Distilled water. (5) 0.06% triciosan. 0.25°/ii phenolic flavor: 23% ethanol. 0.26% Phenolic flavor, 0.50% Sodium lauryl suifate, 0.10% Benzoic acid, 76.08% Distilled water. Triciosan (2.4.4' trichloro-2' hydroxv diphenyl ether) is a nonionic antimicrobial compound widely used as a skindegerming agent. Marked effects on plaque and gingivitis were reported favoring the use of dentifrices containing triciosan and either zinc citrate (Svatun et al. 1987. Svatun et al, 1989, Stephen et al, 1990, Svatun et al. 1990) or polyvinylmethyl ether maleic acid (PVM/ MA) (Sigh et al. 1989. Palmo et al, 1989. Garcia-Goody et al. 1990). A few
512
Ramherg et al. MEAN PlI • MANDIBULAR TEETH
MEAN PlI - MAXILLARY TEETH
Placibo
V»dent
LisUrlne TRN/PVPA 0,12% CHX, TRN/Phan.
Placebo
Vsadent
LIsterlna TRN/PVPA 0,12% CHX, TRN/Phan,
Fig. 3. The mean PI] scores for various groups of teeth in the maxilla (Fig. 3A) and in the mandible (Fig, 3B) on Day 4; TRN/PVPA = triclosan + polyvinyl phosphonic acids, TRN/phen = triclosan + phenolic flavor, X: S,D, Studies have also been published on the effect of triclosan incorporated in mouthrinse preparations, Abello et al, (1990) in a cross-over no oral hygiene study, involving 20 subjects, reported that the 7-day use of a 0,03% triclosan and 0,25% PVM/'MA containing mouthrinse resulted in a 49,8% reduction in plaque scores compared to a placebo rinse, Jenkins et al, (1991) studied the effect of (1) tdciosan containing and (2) sodium lauryl sulphate (SLS) containing mouthwash preparations compared to (3) saline and (4) Corsodyl* (0,2°'(. chlorhexidine gluconate) mouthrinses in 16 subjects during a 4 day period of no mechanical tooth cleaning. They found that mouthrinses containing either 0,2% triclosan or 1% SLS reduced plaque formation significantly compared to saline, but were significantly less effective than Corsodyl*,
Chlorhexidine is a cationic bisbiguanide with a broad antimicrobial spectrum including gram-positive and gram-negative micro-organisms. The antipiaque/ antigingivitis efficacy of chlorhexidine either in a 0,12% or a 0,2% mouthrinse solution is well documented (e,g,, Loe & Rindom Schiatt 1970, Flotra etal, 1972, Loe et al, 1976, Lang et al, 1982, Segreto et al, 1986, Grossman et al, 1986, Banting et al. 1989, Overholser 1990), The rinse preparations were retained in identical but coded bottles. The 6-test solutions were tested in a randomized order. Neither the examiner nor the participants were aware of the content of the rinse used.
ence and amount of plaque was examined and scored by the use of the plaque index system fPlI; Silness & Loe 1964). Scores were obtained from all teeth except 3rd molars and from al) buccal, lingual, mesial, and distal surfaces. The scores from the 4 surfaces of a tooth were added and divided by 4 to give the mean PlI score for the tooth. The mean Pll scores for the individual subject (individual mean P!l) was obtained by adding the score values and dividing by the number of surfaces examined. The scores for groups of teeth and tooth surfaces were calculated to provide the mean PlI score for certain groups of teeth and tooth surfaces.
Clinicai examination
Statistlcai analysis
(6) 0.12% chlorhexidine digluconate solution: 10% ethanol, 0,08% spearmint, 0,2% sorbitan, 0,01% saccharine, 10% glycerine, 0,12% chlorhexidine digluconate, 79,07% distilled water.
All examinations were performed by one examiner (PR), The microbial tooth deposits were disclosed with topically applied erythrosin (Diaplaque, Walco AB, Skarholmen, Sweden), The pres-
The statistical analysis including the Student-Newman-Keul test (SNK-test) was applied with a 5% significance level. Separate analyses were made for the individual mean, for the mean for groups
MEAN Pll - MAXILLARY TEETH
Placebo
Vaadint
Llaterlne TRN/PVPA 0,12% CHX, TRN/Phan.
S
Placebo
MEANPII - MANDIBULAR TEETH
Vaadent
Llaterlna TRN/PVPA 0,12% CHX, TRN/Ptien,
Fig. 4. The mean Pll scores for various groups of tooth surfaces in the maxilla (Fig, 4A) and in the mandible (Fig, 4B) on Day 4; TRN/ PVPA = triclosan + polyvinyl phosphonic acids, TRN/phen = triclosan + phenoIic flavor, X; S,D.
Mouthrinses and plaque formation ALL TOOTH SURFACES < N=1096 )
100 %
• • ^ 0 • D
80
H1
60 40 20
ziBL
PEI SCORE 0
Results Mean PII scores
Placabo Vsadent Usierlne TRN^PVPA 0.12% CHX THN/Phen.
•
1 1 1 PII SCORE 2/3
Fig. i. The % distribution of the surfaces that belonged to PII score category 0 or 2/3 on Day 4; TRN/PVPA = triclosan + polyvinyl phosphonic acids, TRN/phen = triclosan + phenolic flavor. of teeth and tooth surfaces as well as for treatments. Mean PII score
The individual mean PII value for the 10 subjects was first calculated in order to assess the general potential of a given mouthrinses to prevent or retard de novo plaque formation. Comparisons were made with a positive (0.12% chlorhexidine digluconate) and a negative control (placebo) rinse. Subsequently the mean PII scores for different groups of teeth and tooth surfaces were calculated to examine, if the efficacy of the solution tested on de novo plaque formation differed in different parts of the dentition.
% distribution of PII score categories
The efficacy of the solutions tested on de novo plaque formation was further
assessed by analyzing the percentage distribution of surfaces that belonged to different PU score categories; score 0 and score 2 + 3. The number of surfaces that received PII score of 0 or 2 + 3, after each treatment were divided by the number of the surfaces examined to give the percentage of surfaces that belonged to either of these PII score categories. The frequency distribution of different PU score categories were made for all tooth surfaces as well as for groups of teeth and groups of tooth surfaces separately.
Pattern of plaque accumulation (plaque pattern display)
The purpose of this analysis was to illustrate the efficacy of the mouthrinse solutions on de novo plaque formation on each individual tooth surface.
MAXILLARY TOOTH SURFACES ( N=548 )
The mean individual PU scores for all surfaces and for the surfaces in the maxilla and in the mandible after each treatment are reported in Fig. 1 and Table 1. Table 1 also presents the results of the SNK tests. After 4 days of no mechanical tooth cleaning, the mean individual PII scores for all surfaces were 1.46 after placebo treatment (negative control) and 0.53 after 0.12% chlorhexidine treatment (positive control). The corresponding scores after Veadent*, Listerine^, triclosan + PVPA and triclosan+phenolic flavor treatments were 0.94, 0.88, 0,69 and 0.43, respectively (Fig. 1, Table 1). The statistical analysis (SNK tests) revealed that the Veadent^ and the Listerine* mouthwash preparations were more effective than placebo rinse to retard de novo plaque formation. It was also observed, however, that the triclosan + PVPA containing rinse was more effective than Veadent', Listerine* and that triclosan + phenolic flavor and the positive control were more effective than the other 4 preparations tested (Table 1). Thus, all test solutions examined received a significantly lower mean PII score than the placebo solution but, with one exception namely triciosan + phenohc fiavor, yielded a significantly higher mean PII score than the positive control rinse. It was also revealed that (Fig. 1) for a given treatment the mean PU score for the maxillary dentition did not differ from the corresponding score for the mandible. In other words, the amount of plaque formed in the maxilla appeared to be sitnilar to that formed in
MANDIBULAR TOOTTH SURFACES
100
D D
Pil SCORE 0
PII SCORE 2/3
513
PII SCORE 0
Placebo VeadenI Lcsterine TRN/PVPA 0.12% CHX TRN/Phen.
PII SCORE 2/3
f^ig. 6. The % distribution of surfaces that belonged to PII score category 0 or 2/3 in the maxilla (Fig. 6A) and mandible (Fig. 6B) on Day 4.
SI 4
Ramberg et al.
the mandible. The statistical analysis, however, indicated that differences with respect to plaque formation between the different mouthrinse preparations tested were more readily disclosed by individual mean PI! and the mean Pll scores for the maxilla than by the mean Pll scores for the mandible. The results from the analyses performed regarding the mean Pll scores for different groups of teeth and tooth surfaces are reported m Fig, 2 and in Table 2, For all solutions tested with the exception of placebo, it was observed that molars consistently received higher Pll scores than premolars. and premolars higher scores than anterior teeth. Furthermore lingual surfaces consistently received lower Pll scores than the buccal and approximal surfaces. From the results of the SNK tests (Table 2). it could be concluded that (i) all 4 test rinses after 4 days trial had resulted in significantly lower Pll scores than the negative control rinse at aii groups of teeth and tooth surfaces examined, (ii) the mean PIJ scores were significantly higher after Veadent" and Listerine' treatments than after the use of the positive control 0,12% chlorhexidine in all groups of teeth and tooth surfaces,
(except at the lingual surfaces after Listerine* treatment), (iii) there was no significant difference between Veadent* and Listerine' with respect to the mean Pll scores in any groups of teeth and tooth surfaces, (iv) the mean Pll scores for different groups of teeth and surfaces after triclosan-I-phenolic flavor treatment were similar to those obtained after treatment with the positive control, (v) in molars and at approxima! surfaces, the mean Pll scores after triclosan + PVPA treatment were significantly higher than the corresponding scores obtained after treatment with the positive control. The mean PU scores for the groups of teeth and tooth surfaces in the maxilla and in the mandible and for various treatments are presented in Figs, 3, 4. From the data reported it can be seen that the variation with respect to plaque accumulation at various groups of teeth was more pronounced in the maxillary than in the mandibular dentition (Fig, 3), It was also observed that the buccal surfaces of the maxillary teeth consistently accumulated more plaque than the corresponding surfaces in the mandible, while lingual (palatal) surfaces of the maxillary teeth accumulated small
THE PERCENTAGE OF THE SURFACES THAT RECEIVED SCORE 0 APPROXIUAL SURFACES ( n
