Introduction: Microbial contamination and infection of postsurgical area inhibit normal tissue healing process. Minimizing the amount of postoperative dental plaque accumulation leads to more rapid and without complications wound healing. A negative correlation has been found between the amount of dental plaque at the postsurgical site and both gain in soft tissue attachment and osseous fill after periodontal surgical procedures.
Self–performed mechanical plaque removal measures, using toothbrush and interdental brushes or dental floss, is essential for maintaining periodontal and dental health. However, mechanical removal of dental plaque in the early postoperative period (first 7-10 days) is almost not feasible because of sensitivity and pain released from the operated area and many times undesirable due to the risk of tissue irritation and traumatization. Therefore many different protocols have been proposed in order to control postsurgical microbial count, including regular professional removal of plaque and calculus on a weekly basis for the first postoperative month, local application of antiseptic / antimicrobial agents in various formulations and administration of systemic antibiotics.
Chemical supragingival plaque control appears to be an adjunct and not replacement for the mechanical methods, but it is a viable alternative when mechanical measures appear partially or totally ineffective alone or cannot be applied (for example during the immediate postoperative period). There is a plethora of commercially available mouthrinses containing various antimicrobial agents. Those containing digluconate chlorhexidine (CHX) are supposed to be the most effective. Chlorhexidine is a potent antibacterial and antiplaque agent belonging to the bisbiguanide family. It binds strongly to bacterial cell membranes preventing the formation of biofilm. Moreover, it penetrates biofilm of dental plaque and acts against bacteria already embedded. Once adsorbed, and unlike some other antiseptics, CHX shows a persistent bacteriostatic action lasting in excess of 12 hours (substantivity). It cannot lead to development of resistant bacterial strains, even after prolonged use. On the other hand, as any antimicrobial / antiseptic agent, CHX has a number of local side effects. The most frequent one is brown discoloration of the teeth and some restorative materials and the dorsum of the tongue. In a histological level, it seems that CHX may cause an in vitro dose-dependent inhibition of gingival fibroblasts proliferation, which appears to be independent of exposure time to the active substance, or an ex vivo reduction of fibroblasts ability to synthesize collagen, leading to retardation of tissue healing processes. In addition, beyond gingival fibroblasts, CHX appears to negatively affect epithelial cells and peripheral lymphocytes.
A common substance, present in the majority of CHX formulations, is ethanol. Ethanol has been associated with oral mucosa dryness, tissue irritation of postoperative areas, addiction symptoms in chronic alcoholic patients who have stopped drinking and increased risk for oral cancer. Even if no causal relationship between alcoholic mouthwashes and oral cancer has been proved, mainly due to existence of many confounding factors, formulations with ethanol display some disadvantages.
For that reason, chlorhexidine formulations lacking ethanol have been developed in the recent years. The efficacy of these formulations has been investigated in many studies and has been shown to be comparable to that of alcoholic ones. In the majority of those studies, the efficacy of alcoholic and non-alcoholic CHX formulations has been tested on periodontally healthy (or with gingivitis) patients, evaluating their ability to prevent dental plaque formation and inhibit gingival inflammation. The results indicate that there are no significant differences between the above mentioned formulations. However, there are no clinical studies (except one) evaluating the efficacy of CHX formulations with and without ethanol in the postsurgical control of microbial plaque and gingival healing response after periodontal surgical procedures.
Undoubtedly, CHX is the gold standard at a chemical level in the control of plaque and gingivitis. On the other hand, it displays side effects (including adverse effects on tissue healing response) and in some cases its administration is contraindicated. In the literature there are few studies that have evaluated the efficacy of other antimicrobial agents (as for example hexitidine and amine / stannous fluoride), besides CHX, as a postoperative regime of plaque control after periodontal surgery. However, there is a plethora of antimicrobials / antiseptics widely available today, such as factor C31G (a combination of alkyl-dimethyl-glycine and alkyl-dimethyl -amine oxide), that have not been evaluated at a periodontal postsurgical level.
The aim of the present clinical study is to evaluate and compare the effectiveness of three different mouthrinses (alcohol – free CHX, alcohol based CHX and C31G) in postoperative plaque control and early wound healing after periodontal flap surgery.
Materials & Methods: This is a single-center, controlled, randomized, double-blind, parallel design clinical trial. In the study participated 42 patients, females and males, aged 34-69 years old. Participants received periodontal flap surgery for elimination or reduction of residual periodontal pockets and/or for crown lengthening in the regions #13-15 and/or #23-25 and/or #33-35 and/or #43-45, provided that there was no need for osseous graft or membrane or any other regenerative material or biologic mediator application during surgical procedure. Patients randomly allocated to three groups (14 subjects per group). During the first 14 postoperative days, patients instructed to rinse with one of the following three mouthwashes: a combination of alkyl-dimethyl-glycine and alkyl-dimethyl -amine oxide (C31G, Therasol, InterTrade, Group A), chlorhexidine 0.12% without ethanol (Chlorhexil 0,12%, Intermed, Group B) and 0.12% chlorhexidine with ethanol (Plak out 0,12%, Omega Pharma, Group C). During the whole observation period, subjects refrained from any mechanical effort of plaque removal at the operated areas. Postsurgical plaque control and early wound healing were evaluated according to the following parameters:
1) Clinical photographs of buccal aspect of teeth at the operated areas (canine, 1st premolar, 2nd premolar) with fluorescent dental plaque disclosing agent (baseline - immediately prior to surgery, 7th and 14th postoperative day). Photographs were processed in PC Adobe Photoshop Program, in order to evaluate the % area covered by dental plaque (index PA%).
2) Plaque index (PI) (14th postoperative day).
3) Early wound healing index (EHI) (7th and 14th postsurgical days).
4) Supragingival dental plaque samples collection for microbiological evaluation of total bacterial count applying the technique of quantitative real time polymerase chain reaction (quantitative real time PCR) (14th postoperative day).
Statistical analysis was performed with the statistical package Stata 13.1 (Stata Corp., TX USA). P-values less than 0.05 were considered as statistically significant.
Results: Regarding postsurgical plaque control, as evaluated by plaque index (PI), the comparison among groups revealed significantly lower PI values in group B (CHX without ethanol) compared to A (C31G) (p = 0,012) and even lower values in group C (CHX with ethanol) with respect to A (p <0,001). Also, group C showed significantly lower PI values compared to group B (p <0,001). In particular, premolars (1st premolar: OR = 3.25, 2nd premolar: OR = 4,64, p <0,001), proximal tooth surfaces (mesial: OR = 7.19, distal: OR = 12,58, p <0,001) and smoking (OR = 20,41, p <0,001) were associated with significantly higher PI values.
Regarding PA% index, 7 days postoperatively median values were 22.8%, 20.6% and 11.2% in groups A, B and C, respectively. At 14th postsurgical day, values for groups A, B and C were 32.5%, 14.9% and 11.2%, respectively. Between two examinations, there was no significant difference in PA% values within each group (14 vs 7 days, coefficient b = 0,09, p = 0,416). At day 14, group B showed an average of 16 percentage units lower PA% compared with group A (significant difference, p = 0,049) and group C displayed 21 percentage units lower PA% compared to A (significant difference, p = 0,005). Group C was not significantly different compared to B (p = 0,421).
Early wound healing, as evaluated by EHI registration, was not significantly different among groups (all p-values are among group comparisons was > 0.05) 7 days after surgery. At 14th postoperative day, EHI values in group C were significantly lower compared to group B (p = 0,007). Group A showed no significant differences compared with groups B (p = 0,130) and C (p = 0,207). Between 7th and 14th postsurgical day, a significant reduction of EHI values (improved wound healing) was recorded at groups A (p < 0,001) and C (p <0,001). In contrast, in group B there were no significant differences between two recordings (7 and 14 days) (p = 0,557). Smoking was not significantly correlated to healing response. In both examinations (7 and 14 days), there were no significant differences of EHI values among smokers, ex-smokers and non-smokers (7th day: p = 0,486, 14th day: p = 0,514).
A trend for higher EHI values (deteriorating healing response) as increased dental plaque accumulation (higher PI values) was recorded, but this observation was not statistically signifficant (borderline non-significant difference between PI = 3 and PI = 1, p = 0,051).
At microbiological evaluation, results were recorded from all patients in group A, while in groups B and C there were no microbiological data from six patients (three subjects in each group). The amount of total bacterial load (median values) was 0,416ng in group A, 0,521ng in group B and 0,032ng in group C. The levels of bacterial counts, expressed as total number of bacteria (x106) were 38.470, 48.190 and 3.020 for groups A, B and C, respectively. Differences between groups A and B were not statistically significant (p = 0,612), while group C showed significantly lower bacterial counts comparatively to other two groups (p <0,001).
The amount of bacterial load was not correlated with EHI values (all p-values greater than 0.05), which indicates that microbial counts level did not affect the early healing response of gingival tissues.
Finally, there were no significant differences in the levels of total bacterial counts among smokers, former smokers and non-smokers (p = 0,624 and 0,538 for ex-smokers and smokers, respectively).
Conclusions: Within the limitations of this study we can conclude the following:
• Regarding postsurgical plaque control (for an observation period of 14 days), both clinical and microbiological data indicated that chlorhexidine with ethanol is superior to the other formulations.
• CHX with ethanol was superior in reducing total bacterial load compared to the other two solutions, which in turn were not significantly different from each other.
• Regarding early wound healing response, there was no significant difference among the evaluated formulations, 7 days after periodontal surgery. This may indicate that in periodontal surgical procedures where sutures are anticipated to be removed in such a time period (7 days), chlorhexidine and C31G agent could lead to a similar tissue healing response profile.
• Active agent C31G appeared to be as effective as chlorhexidine formulations (non-statistically significant difference) at the level of early postsurgical periodontal tissue healing response (during the 14-day observation period). Moreover, CHX with ethanol was superior to non-alcoholic CHX at the same time period (14 days follow-up). This observation may suggest that in cases where sutures have to remain more than seven days, use of mouthrinses containing ethanol should be preferred.
• The findings indicate that the presence of ethanol increases the efficacy of chlorhexidine. In addition, solutions with the active agent C31G could be used alternatively to chlorhexidine in the early postsurgical period.