Effect of toothbrushing with chlorhexidine gel on salivary microflora, oral hygiene, and caries

abstract – The effect of daily toothbrushing with 0.5 % chlorhexidine-containing gel for 12 months was evaluated in a double-blind study in 37 dental students. The active gel did not markedly influence plaque formation, gingival conditions, or caries as compared with placebo gel treatment. Salivary bacterial counts were performed on subgroups of six subjects using chlorhexidine gel and on six using placebo gel. No differences in the effect of treatment on the microorganisms studied in the two subgroups could be detected except for S. sanguis . The percentage of this species decreased in the placebo group and increased in the chlorhexidine group. The difference became significant after 2 weeks. A tendency to a greater reduction of S. mutans noted in the chlorhexidine group was most marked in individuals who had high initial counts of this species. The proportion of S. sanguis , which could grow on chlorhexidine-containing mitis salivarius medium, increased and after 12 months of chlorhexidine treatment averaged 34 % of cultivable S. sanguis compared with 0.002 % prior to treatment. The number of less sensitive S. sanguis decreased in the 12 months following termination of treatment. There was no observed tendency for the selection or proliferation of other streptococci, gram-negative rods, yeasts, or staphylococci.     

Prolonged oral reduction of Streptococcus mutans in humans after chlorhexidine disinfection followed by fluoride treatment

The effect of oral chlorhexidine gel treatment supplemented with fluoride applications was studied in subjects with high salivary levels of S. mutans. In two experiments short-term treatment with a 1% chlorhexidine gel was followed by applications of either a 1% NaF gel daily for 2 weeks or a 1% NaF gel daily for 6 weeks supplemented twice with topical application of an 8% SnF2 solution. The salivary numbers of S. mutans were lower in the test group than in the placebo group after 6 and 12 weeks in experiments 1 and 2, respectively, and considerably lower than the pretreatment values. The findings show that fluoride applications can be a valuable adjunct to chlorhexidine treatment for combatting S. mutans.     

Prolonged oral reduction of Streptococcus mutans in humans after chlorhexidine disinfection followed by fluoride treatment

Abstract – The effect of oral chlorhexidine gel treatment supplemented with fluoride applications was studied in subjects with high salivary levels of S. mutans. In two experiments short-term treatment with a 1% chlorhexidine gel was followed by applications of either a 1% NaF gel daily for 2 weeks or a 1% NaF gel daily for 6 weeks supplemented twice with topical application of an 8% SnF₂ solution. The salivary numbers of S. mutans were lower in the test group than in the placebo group after 6 and 12 weeks in experiments 1 and 2, respectively, and considerably lower than the pretreatment values. The findings show that fluoride applications can be a valuable adjunct to chlorhexidine treatment for combatting S. mutans.     

Gengigel凝胶在菌斑性牙龈炎治疗中的作用

目的:观察局部应用Gengigel凝胶治疗菌斑性牙龈炎的临床疗效。方法:采用口内自身对照,选择菌斑性牙龈炎患者30例,每位受试对象口内每个象限选取至少2个磨牙和(或)前磨牙作为受试牙。4个象限分别给予洁治 用Gengigel凝胶(SG组),洁治(S组),用Gengigel凝胶(G组),空白对照(C组)等处理。观察治疗前及治疗后4d和7d的菌斑指数(PLI),牙龈指数(GI)和龈沟液流速(SFFR)的变化。结果:SG组的各项指标(除PLI外)下降显著快于S组(P<0.05);G组的各项指标下降显著快于C组(P<0.05)。结论:Gengigel凝胶辅助洁治术或单独使用Gengigel凝胶对菌斑性牙龈炎均有一定治疗效果。     

Effect of chlorhexidine gel treatment supplemented with chlorhexidine varnish and resin on mutans streptococci and Actinomyces on root surfaces

The supplementary effect of chlorhexidine varnish and resin on the reappearance of mutans streptococci and Actinomyces spp. on root surfaces after chlorhexidine gel treatment was studied. In 8 subjects with many restored tooth and exposed root surfaces, highly colonized with mutans streptococci, chlorhexidine varnish and resin were applied to the teeth on one side of the mouth and resin alone to the other side. This treatment significantly prolonged the time period of reduced salivary levels of mutans streptococci when added to a preceding period of chlorhexidine gel treatment. In 3 of the 8 subjects, mutans streptococci were undetected for more than 4 weeks after treatment. There was a significant difference between the chlorhexidine varnish/resin side and the resin side for 5 weeks with regard to the mean numbers of mutans streptococci in root surface plaque, whereas for the Actinomyces spp. no significant differences were found. In 2 subjects harboring both Streptococcus mutans and S. sobrinus, the population of S. sobrinus reappeared more readily in saliva and plaque than S. mutans. The chlorhexidine treatment was less effective in suppressing the population of Actinomyces viscosus/naeslundii than the mutans streptococci.     

Effect of a fluoride-containing chlorhexidine gel on bacteria in human plaque.

The effect on the plaque flora of a fluoride-containing chlorhexidine gel in mouthpieces was studied in seven subjects. Use of the gel during a 3-month period resulted in a change in the pattern of sensitivity to cholorhexidine in the plaque flora as displayed by determination of the minimal inhibitory amount (MIA) of the drug in agar diffusion assays. Three months after the use of gel was discontinued, the MIA value for plaque bacteria had returned to its original level. The relative proportions of S. mutans and S. sanguis in plaque changed during the chlorhexidine period. Thus S. mutans could not be detected in plaque samples after 3-month use of the gel, and the frequency of S. sanguis was altered.     

Effect of chlorhexidine gel treatment on Streptococcus mutans population in human saliva and dental plaque

Abstract – The effect of topical application of a 1% chlorhexidine gel on the population of S.mutains in dental plaque and saliva was studied in five subjects highly infected with the organism. After treatment for 5 min daily for 14 d, S. mutans was not detected in three of the subjects and counts of 700 colony-forming units or less per ml of saliva were found in the other subjects. Reappearanceof S. mutans was slow and did not reach pretreatment level until 14 weeks or more after therapy. The proportion of S. saguis in plaque increased temporatrily after chlorhexidine treatment, whereas the population of lactobacilli was unaffected. These observations indicate that short-term use of chlorhexidine is of value in controlling oral infection of bumans by S. mutans.     

Effect of intensive treatment with chlorhexidine on number of Streptococcus mutans in saliva

The effect of intensive treatment with chlorhexidine on the number of S. mutans in saliva was studied in 24 schoolchildren highly infected with this organism. Chlorhexidine gel in individual dental trays was applied under supervision on two consecutive days, four times the first day and three times the second day. The number of S. mutans in saliva was monitored for 6 months. Immediately after treatment, the number was greatly reduced in all of the children. Thirty days after treatment only three children had more than 2 X 10(5) S. mutans/ml saliva, and after 4 months, 11 children still had less than 2 X 10(5) S. mutans/ml saliva. After 6 months the effect of the treatment was obvious in 20% of the children. The results indicate that intensive treatment with chlorhexidine can be used to reduce the S. mutans infection. The antimicrobial treatment, however, should be individually controlled because of variations in the response of the subjects.     

Effect of a fluoride-containing chlorhexidine gel on bacteria in human plaque

abstract — The effect on the plaque flora of a fluoride-containing chlorhexidine gel in mouthpieces was studied in seven subjects. Use of the gel during a 3-month period resulted in a change in the pattern of sensitivity to chlorhexidine in the plaque flora as displayed by determination of the minimal inhibitory amount (MIA) of the drug in agar diffusion assays. Three months after the use of gel was discontinued, the MIA value for plaque bacteria had returned to its original level. The relative proportions of S. mutans and S. sanguis in plaque changed during the chlorhexidine period. Thus S. mutans could not be detected in plaque samples after 3-month use of the gel, and the frequency of S. sanguis was altered.     

Effect ofintensive treatmetn with chlorhexidine on number of Streptococcus mutans in saliva

Abstract – The effect of intensive treatment with chlorhexidine on the number of S. Mutans in saliva was studied in 24 schoolchildren highly infected with this organism. Chlorhexidine gel in individula dental trays was applied under supervision on two concecutive days, four times the first day an dthree times the second day. The number of S.mutans in saliva was monitored for 6 months. Immediately after treatment, the number was rreatlyreduced in all of the children. Thirty days after treatment only three children had more than 2×10⁵ S.mutansmi saliva, and after 4 months, 11 children still had less than 2×10⁵ S.Mutans/ml saliva. After 6 months the effect of the treatmetn was obvisous in 20% of the children. The results indicate that intensive treatment with chlorhexidine can be used to reduce the S.mutans infection. The antimicrobial treatment, however, should be individully controlled because of variations in the response of the subjects.     

Recolonization of human tooth surfaces by Streptococcus mutans after suppression by chlorhexidine treatment

In eight subjects who were initially highly colonized with Streptococcus mutans and who used a 1% chlorhexidine gel, the numbers of this organism were suppressed in both plaque and saliva. Bacterial plaque samples were obtained from all tooth surfaces, and the recolonization pattern of S. mutans was studied over a 26-week period. At baseline, 83% of all surfaces harbored S. mutans with buccal surfaces colonized in higher frequency than the others. After chlorhexidine treatment, the proportion of tooth surfaces colonized by S. mutans was reduced to a low level. Re-appearance was slow. S. mutans was first recovered from the most posterior teeth in the mouth, the molar surfaces were recolonized earlier than were those of pre-molars and anterior teeth, and the buccal surfaces were recolonized more readily than were the other tooth surfaces. The data show that there is a specific recolonization pattern of S. mutans after chlorhexidine treatment, and that the re-emergence of S. mutans is most probably due to regrowth of bacteria which have not been eradicated.     

Microbial aspects of preventive regimes in patients with overdentures

The aim of this study was to test effects of preventive regimes using fluoride and chlorhexidine to prevent caries and periodontal diseases in 34 patients with overdentures. The patients, who were treated with immediate overdentures, were distributed at random into three experimental groups. In these groups, different gels--a placebo, a fluoride, and a chlorhexidine-fluoride gel--were tested by daily application. Supragingival plaque samples from selected surfaces of two abutment teeth were taken at one week, and at one, three, and six months after initial insertion of the overdenture. The placebo and fluoride gel influenced neither total CFU nor S. sanguis and A. viscosus/naeslundii counts. In the placebo group, but not in the fluoride group, S. mutans levels increased significantly, indicating the caries risk involved in overdentures. The use of chlorhexidine-fluoride gel resulted in a long-term suppression of total CFU. Further, S. mutans was found to be selectively suppressed to below detection level. A. viscosus/naeslundii was initially strongly suppressed, but after three months a partial return of the population was noticed. S. sanguis was relatively insensitive to the chlorhexidine-fluoride gel. It is concluded that a daily application of a chlorhexidine-fluoride gel is effective against plaque formation and S. mutans on abutment teeth in overdentures.     

The effects of chlorhexidine gel on Streptococcus mutans infection in 10-month-old infants: a longitudinal,placebo-controlled,double-blind trial

PURPOSE: This study investigated the long-term effects of 0.2% chlorhexidine gel, used as a weekly brush-on gel, on Streptoccocus mutans infection in 10-month-old infants. METHODS: The investigation followed the criteria of a placebo-controlled, double-blind, longitudinal clinical trial. Infants were recruited at birth and oral microbiological swabs were taken at 3 monthly intervals, together with medical, dental, dietary and brushing histories. Children who were found to be colonized with S. mutans were randomly assigned to either the chlorhexidine-gel group (N = 50) or placebo gel group (N = 46), and parents were instructed to brush the gel on the teeth once per week for 12 weeks. In another control group (N = 210), infants did not use either chlorhexidine or placebo gels. Saliva samples were cultured using S. mutans-selective tryptone-yeast extract-cysteine-sucrose-bacitracin (TYCSB) agar. The mean age of the children was 10.2 +/- 2.6 months at the start of the trial and subjects were followed until the ages of 18 months. RESULTS: In the children with initial low S. mutans counts of < 300 CFU/mL, there was a significant percentage reduction in S. mutans counts in the chlorhexidine-gel group compared to the placebo gel and no-gel control groups after 3 months of weekly gel brushing. However, no significant differences with the placebo group were observed after 15 months of follow-up. There were 39 children (41%) who achieved reduction of their S. mutans to 0 CFU/mL. Compared to those who remained infected with S. mutans, these children had higher toothbrushing frequencies (P < .001) and toothpaste use (P < .001), as well as lower frequencies of daily feeds (P < .01), and lesser weekly frequencies of sweet solids and liquids (P < .001). CONCLUSIONS: Children with relatively low initial S. mutans counts (< 300 CFU/mL) showed a reduction in S. mutans counts in the first 3 months when 0.2% chlorhexidine gel was brushed on the teeth weekly. No differences were observed when compared with the placebo and no-treatment groups at later follow-up periods.     

Effect of professional flossing with chlorhexidine gel on approximal caries in 12- to 15-year-old schoolchildren

The aim of the investigation was to evaluate the effect of chlorhexidine gel treatment on caries development of approximal tooth surfaces and on salivary counts of Streptococcus mutans. 220 12-year-old schoolchildren, divided into three groups, participated: (1) chlorhexidine gel group (n = 72), (2) placebo gel group (n = 77), and (3) control group (n = 71). The study was carried out double blind with respect to the two gel groups. Group 1 was treated 4 times/year with 1% chlorhexidine gel and group 2 with a placebo gel. Approximately 1 ml of gel was applied interdentally by means of a flat dental floss. The control group did not receive any gel treatment or flossing. Number of S. mutans in the saliva was estimated on five occasions during the study with the spatula method. After 3 years, the mean approximal caries increment, expressed as new DFS, was 2.50 in the chlorhexidine gel group and 4.30 in the placebo gel group (p less than 0.05). The corresponding figure in the control group was 5.25 (p less than 0.001 when compared to group 1). 44% of the children in the chlorhexidine gel group and 32% in the placebo gel group did not develop any new approximal caries lesion during the 3-year observation period compared to 18% in the control group (group 1-3 p less than 0.001; group 2-3 p less than 0.05). The number of new approximal fillings (FS) was 0.24 in the chlorhexidine gel group, 0.75 in the placebo gel group and 0.82 in the control group (group 1-3 p less than 0.01; group 2-3 p less than 0.05). There was no statistically significant difference between the groups with respect to numbers of S. mutans in saliva. However, there were more individuals with low numbers of S. mutans in the chlorhexidine gel group at the final examination compared to the baseline level (p less than 0.05).     

Clinical efficiency of 2% chlorhexidine gel in reducing intracanal bacteria

This study evaluated the clinical efficacy of 2% chlorhexidine (CHX) gel on intracanal bacteria reduction during root canal instrumentation. The additional antibacterial effect of an intracanal dressing (Ca[OH](2) mixed with 2% CHX gel) was also assessed. Forty-three patients with apical periodontitis were recruited. Four patients with irreversible pulpitis were included as negative controls. Teeth were instrumented using rotary instruments and 2% CHX gel as the disinfectant. Bacterial samples were taken upon access (S1), after instrumentation (S2), and after 2 weeks of intracanal dressing (S3). Anaerobic culture was performed. Four samples showed no bacteria growth at S1, which were excluded from further analysis. Of the samples cultured positively at S1, 10.3% (4/39) and 8.3% (4/36) sampled bacteria at S2 and S3, respectively. A significant difference in the percentage of positive culture between S1 and S2 (p < 0.001) but not between S2 and S3 (p = 0.692) was found. These results suggest that 2% CHX gel is an effective root canal disinfectant and additional intracanal dressing did not significantly improve the bacteria reduction on the sampled root canals.     

Bacterial quantification in teeth with apical periodontitis related to instrumentation and different intracanal medications: a randomized clinical trial

The antibacterial efficacy of intracanal medication with calcium hydroxide [Ca(OH)2], 2% chlorhexidine gel (CHX), and a combination of both [Ca(OH)2/CHX] was assessed in teeth with chronic apical periodontitis. Thirty-three canals were instrumented, randomly divided into three groups, and medicated with either Ca(OH)2, CHX, or Ca(OH)2/CHX. Bacteriological samples obtained from the operative field and the root canals before (S1) and after instrumentation (S2) in the first treatment session, and after medication (S3) in the second session 1 week later, were assessed for bacterial growth, observed by turbidity and in agar plates, and viable colony-forming unit (CFU) counts. Bacterial growth and CFU counts decreased significantly from S1 to S2 (Mann-Whitney, p<0.05). Differences in growth and counts between S2 to S3 were not statistically significant for all three intracanal medication groups. It was concluded that the antibacterial efficacy of Ca(OH)2, CHX, and Ca(OH)2/CHX was comparable.     

Comparison of the antimicrobial effect of the application of chlorhexidine gel, amine fluoride gel and stannous fluoride gel in debrided periodontal pockets

The clinical and microbiological effect of locally-applied chlorhexidine gel 2%, amine fluoride gel 1.25%, stannous fluoride gel 4% or placebo gel in 40 periodontal pockets of 10 patients were studied. The gels were applied 3 x within 10 min. after mechanical debridement of the pockets. The treatment effect on the subgingival microflora was evaluated by microscopic and culture studies of the subgingival plaque samples. In addition, supragingival plaque, bleeding after probing and probing pocket depth were scored. Examination were carried out before and during a period of 36 weeks after treatment. At the start, the cultured microflora consisted mainly of anaerobic Gram-positive bacteria. Following treatment, the clinical parameters were significantly reduced. Concomitantly, the %s of spirochetes, motile rods and non-motile rods decreased significantly. A significant decrease was also found in the total anaerobic count, whereas the facultative counts remained at the same level found before treatment. This suggested that the treatment resulted in a mainly facultative subgingival microflora. The % Gram-negative rods showed a significant reduction after treatment, but returned to base line at week 12. Statistical analysis of the bacteriological and clinical examinations failed to demonstrate any significant differences between the 4 treatment groups. Thus, in comparison to the placebo gel, subgingival application of chlorhexidine gel 2%, amine fluoride gel 1.25% or stannous fluoride gel 4% did not augment the effect of mechanical debridement on bacteriological and clinical parameters during the experimental period of 36 weeks. However the indicated treatments resulted in a facultative subgingival microflora which is compatible with the host.     

局部应用甲硝唑辅助治疗深牙周袋的疗效分析

目的：比较局部应用25％甲硝唑牙科用凝胶剂（依俐周）辅助龈下刮治与单纯龈下刮治,治疗深牙周袋的疗效。方法：18例中,重度成人牙周炎患者,选择其左右侧对应牙,牙周袋探诊深度（Probing Depth,PD)大于等于7mm但小于等于10mm,且探诊出血的位点,进行随机,单盲,对照试验,0天时试验牙接受龈下刮治及依俐周局部用药,对照牙只接受龈下刮治,于基线,后线,治疗后21天,91天,时,进行PD和柏出血（Bleebing On Probing BOP)及龈下菌斑涂片检查,结果：依俐周局部用药部位,其D害治疗后91天,改善了2．91mm,明显大于对照组改善值1．83mm,治疗后21天,试验组BOP由基线时的100．0降至86．4％,而对照组BOP无明显改善,治疗后21天试验组龈下菌斑中螺旋体的百分离由基线之24．1％降至6．2％,而对照组无显著变化。结论：局部应用25％甲硝唑牙科用凝胶辅助龈下辞治疗 深牙周袋,可获得较好的临床效果。     

Comparative analysis of endodontic pathogens using checkerboard hybridization in relation to culture

Background/Aim:  The purpose of this study was to detect bacterial species and to quantify the total number of bacteria from samples of infected root canals before (S1) and after chemo-mechanical preparation using 2% chlorhexidine (CHX) gel as auxiliary chemical substance (S2) and after 7 days of intracanal dressing (S3) to compare microbial changes.
Method:  Twenty-four teeth were selected for this study. Chemo-mechanical preparation was performed using 2% CHX gel, then three different intracanal medicaments [M1: Ca(OH)₂ paste; M2: 2% CHX gel; and M3: Ca(OH)₂ paste plus 2% CHX gel] were used for 7 days. Checkerboard DNA–DNA hybridization was performed to detect 40 bacterial species. Aerobic and anaerobic culture techniques were used to determine the bacterial community by counting the colony-forming units (CFU).
Results:  The species most frequently identified by checkerboard in S1 were: Fusobacterium nucleatum ssp . polymorphum , Treponema socranskii ssp. socranskii , Parvimonas micra and Enterococcus faecalis. In S2 and S3 a total of eight different species were identified; and only one of them was gram-positive ( E. faecalis ). Microorganisms were not identified after use of M2 for 7 days. The quantification obtained on agar plates ranged from 4 × 10⁵ to 2.6 × 10⁶ CFU/ml in S1, mean CFU was reduced by 99.96% in S2, and there was no statistical difference between the CFU in S2 and S3.
Conclusion:  The antibacterial effect of the mechanical preparation supplemented by the use of an antibacterial auxiliary substance greatly reduced the microorganisms in the main root canal.     

Caries prevention by professional fluoride gel application on enamel and dentinal lesions in low-caries children

In a double-blind randomized controlled clinical trial, the caries-reducing effect of semi-annually applied fluoride gel in a low-caries child population initially aged 4.5-6.5 years (n = 773) has been investigated. Secondary analyses of the data were performed to study the caries reduction including non-cavitated lesions. The treatment effect of fluoride gel was calculated as preventive fraction (PF). When enamel lesions were included in DFS count (D(2) grade), the PF was 22% as compared to 26% counting dentinal lesions. The PFs showed that the mean effect of professionally applied fluoride gel was highest (71%) for D(3)S in the permanent dentition and lowest for d(3)s in the primary dentition (5%). The PFs for approximal and buccal and lingual surfaces of the permanent dentition significantly decreased from 80 to 25% and from 60 to 37% when enamel lesions (D(2)S) were included. With the exception of the buccal and lingual surfaces, in the primary dentition the PFs varied slightly when enamel lesions were included. Inclusion of non-cavitated lesions in the treatment effect statistics did not change the former conclusion that the treatment effect of fluoride gel application on dental caries reduction in a low-caries child population was considered not clinically relevant.