Investigating the effect of propolis-containing chewing gum in comparison with propolis-containing mouthwash on reducing gingival inflammation in patients with gingivitis (2025)

Background

The aim of this parallel clinical trial is to investigate the effectiveness of propolis-containing chewing gum and mouthwash in reducing gingival inflammation in patients with gingivitis referred to the Periodontology Department of Yazd Dental School in 2022.

Methods

For this purpose, a total of 20 patients were randomly assigned to either the mouthwash group or the chewing gum group. Plaque index (PI), papillary bleeding index (PBI), and gingival index (GI) were recorded before and after one week of using the assigned product, followed by scaling and root planing (SRP). Statistical analysis was performed using Chi-square, T-Test, Mann-Whitney, Paired Samples, and Wilcoxon Signed Ranks tests.

Results

Both groups showed significant reduction in PI (p-value = 0.0001), PBI (p-value = 0.0001), and GI (p-value = 0.003 for chewing gum group and p-value = 0.006 for mouthwash group). There was no significant difference between the two groups in terms of PI (p-value = 0.686), PBI (p-value = 0.737), and GI (p-value = 1.000).

Conclusion

It can be concluded that both propolis-containing chewing gum and mouthwash can effectively reduce dental plaque, papillary bleeding, and gingival inflammation in patients with gingivitis. No significant difference was observed between the two products in terms of effectiveness.

Trial registration

The study was registered at IRCT (IRCT20220420054592N1).It was retrospectively registered on 11/6/2022.

Periodontal diseases, including gingivitis and periodontitis, have a multifactorial inflammatory etiology involving pathogenic bacteria in the oral cavity that trigger immune system responses and inflammation [1,2,3]. Early detection and treatment of gingivitis is crucial since it is the primary cause of tooth loss [4] and is associated with systemic diseases, including cardiovascular disease, diabetes, osteoporosis, premature labor, pulmonary diseases, infectious diseases, and cancers [5]. Effective management of periodontal diseases, particularly gingivitis, can significantly impact both oral and systemic health. Dental plaque buildup at the gingival margin, which results in gingival stimulation and sensitization and ultimately produces gingival bleeding, is the hallmark of gingivitis [6]. If left untreated, gingivitis can progress to periodontitis [7]. Gingivitis is the mildest form of periodontal disease and is reversible. A good oral hygiene regimen can improve its prognosis [8]. There are two kinds of gingivitis: non-plaque related and plaque-related. Edema, redness, sensitivity, sporadic bleeding, or bleeding after brushing are typical indicators of gingivitis [4].

While tooth brushing is the most effective way of controlling plaque, some individuals may not perform adequate mechanical cleaning. Therefore, adjunctive use of antimicrobial mouthwashes can aid in controlling plaque in patients with gingivitis [9]. Common mouthwashes, such chlorhexidine, help treat gingivitis and periodontitis and reduce plaque buildup, but they can also cause foul taste, vomiting, diarrhea, and burning in the mouth. Thus, long-term use of these products is not recommended [9,10,11,12].

Compared to chemical mouthwashes, herbal mouthwashes, like those made of persika, matrica, and propolis, are less likely to have side effects and be hazardous [13]. Propolis, which is more effective against oral bacteria than chlorhexidine and Listerine [14], has many potential health benefits, including preventing oral and dental diseases [15]. Its components include resin and beeswax (50–70%), pollen (5–10%), amino acids, minerals, vitamins A, B, and E, phenols, and aromatics [16]. A large amount of propolis’s resin is composed of flavonoids, which are mostly responsible for the substance’s antibacterial, anti-inflammatory, antiviral, antifungal, anti-inflammatory, and antioxidant qualities [17]. In addition to mouthwashes and toothpaste, antiplaque-containing chewing gums can serve as an additional tool for routine dental care. Chewing gum can stimulate salivary flow and mechanically clean teeth [18, 19]. In order to determine which treatment reduces gingival inflammation in patients with gingivitis sent to the Dentistry Faculty of Yazd City between 2022 and 2023, this study will compare the effectiveness of propolis-containing chewing gum with propolis mouthwash.

This research is a double-blind, randomized, controlled clinical trial with a parallel design that was carried out in 2022–2023 at Yazd Shahid Sadoughi University of Medical Sciences’ Dental School. Patients who made an appointment at this university’s department of periodontology in 2022 made up the target population. The study was approved by the Yazd Shahid Sadoughi University of Medical Sciences ethical council and complied with its requirements for clinical trials(code of ethics: IR.SSU.REC1401.015). The study was registered at IRCT (IRCT20220420054592N1). Written informed consent was obtained from all subjects before screening and enrollment procedures. The study adheres to CONSORT checklist.

The study population comprised of 20 patients aged 18 to 65, diagnosed with gingivitis, and referred to the Periodontist Department of Yazd Dental School. Patients were selected using a random sampling method to ensure unbiased representation in the study. The method used was simple randomization which was done using Random allocation software version 1. Inclusion criteria for the study were patients diagnosed with gingivitis, referred to the Periodontology Department of the School of Dentistry, and having no systemic diseases and having at least 20 teeth, including posterior teeth. Patients also needed to have no sensitivity to mouthwash or chewing gum containing propolis, and should not have been smoking or pregnant or breastfeeding during the study period. The exclusion criteria incorporated patients who had received antibiotics or other types of gum during the study period, or demonstrated noncompliance in using the propolis-infused chewing gum or mouthwash.

A total of 20 patients were randomly assigned to two groups, with 10 patients in each group. Prior to the implementation of the intervention, baseline assessments were conducted for each patient, which included recording the values of the plaque index, gingival index, and bleeding index. All patients received a comprehensive oral and dental examination by a qualified dentist and were provided with oral hygiene instructions that included guidance on the correct brushing technique using the MODIFIED BASS method, as well as proper flossing techniques. Then, the patients were randomly assigned to either the Propolis chewing gum group or the Propolis mouthwash group.

In this periodontics study, the assessment of gingival inflammation involved the utilization of a periodontal probe for the quantification of the gingival index, in accordance with the criteria outlined by Loe [20] The evaluation of dental plaque levels was conducted using the O’Leary index. To derive this index, patients were administered a disclosing agent for a brief duration, after which it was removed. This agent induced coloration on all surfaces susceptible to plaque accumulation. Subsequently, four surfaces (mesial, distal, lingual, and facial) along the dentogingival junction were examined for each tooth to determine the presence or absence of colored biofilm [21]. The index percentage was subsequently computed as follows (Eq.1):

For the assessment of the papillary bleeding index, the procedure involved retracting the cheek and gently inserting a periodontal probe to a depth of 1mm within the distal sulcus of the most posterior tooth in each quadrant on the buccal surface. The probe was then moved slowly along the sulcus, extending from the distal to the mesial interproximal region, encompassing all teeth within the quadrant from the facial aspect. A 30-second waiting period followed, during which any bleeding at the distal, mesial, and facial surfaces was observed. This process was replicated for the palatal/lingual surfaces, with the bleeding status being recorded. Consequently, four distinct numerical values were obtained for each tooth [21]. After recording the data for all teeth, the index percentage was computed as follows (Eq.2):

The participants in the mouthwash group were instructed to dilute 20–25 drops of propolis mouthwash (Soren Tek Tos Mashhad, a commercial product) in 100ml of water and use the solution to gargle for one minute, twice a day for one week. Thirty minutes after using the mouthwash, participants were instructed not to eat or drink anything. They were also instructed to maintain regular oral hygiene practices, including brushing and flossing. Participants in the propolis gum group were instructed to chew propolis gum (produced by Saqez Sazi Production Company, Kurdistan) for 20min, three times a day, after each meal for a total of 1h per day for a week. They were also advised to maintain their regular oral hygiene practices.

Following one week of using propolis mouthwash or gum, the plaque, gingival, and bleeding indices were recorded for both groups and all the patients received SRP. A dental student, under the supervision of a periodontologist, compared the indices before and after using propolis in both groups and between the two groups. Non-compliance in using mouthwash or chewing gum containing propolis was considered an exclusion criterion to ensure that the results of the study were not affected by participants who did not comply with the treatment protocol. SPSS 25 was used to analyze the collected data. Randomization was conducted using software method(Random allocation software version 1). Statistical tests for normality, such as the Shapiro-Wilk test and Kolmogorov-Smirnov, were performed before applying parametric tests. Independent or coupled t-tests or their non-parametric equivalents, including Mann-Whitney and Wilcoxon signed-rank tests, were used. The statistical data were interpreted using Chi-square analysis.

This study used a parallel-design randomized controlled trial (RCT) to examine the effectiveness of chewing gum and propolis mouthwash in treating gingivitis. The target population consisted of 20 systemically healthy patients with gingivitis who presented to the periodontology department of a dental school. Of the 20 patients, 6 (30%) were men and 14 (70%) were women. With a minimum age of 19 and a maximum age of 47, the mean age of the patients in the mouthwash group was 26.8 years, and in the chewing gum group it was 28.6 years. Data is provided in table 1. Age differences between the two groups were not statistically significant (P-value = 0.606). With 7 females and 3 males in each group, the sex distribution was the same in both (P-value = 1).

Paired samples test was used to compare the mean plaque index (PI) and papillary bleeding index (PBI) before and after the intervention in the mouthwash and chewing gum groups separately. In the mouthwash group, the mean PI was reduced significantly from 62.35 before the intervention to 47.69 after the intervention (P-value = 0.0001). Additionally, the mean PBI was significantly reduced from 61.03 before the intervention to 38.34 after the intervention (P-value = 0.0001). Details are provided in table 2.

In the mouthwash group, the Wilcoxon signed ranks test showed a significant decrease in the total gingival index from a mean of 2.25 before the intervention to 2 after the intervention (p-value = 0.006). In the chewing gum group, the average plaque index (PI) significantly decreased from 64.47 before the intervention to 45.72 after the intervention (p-value = 0.0001). Additionally, the average papillary bleeding index (PBI) significantly decreased from 60.23 before the intervention to 36.67 after the intervention (p-value = 0.0001). The Wilcoxon signed ranks test showed a significant decrease in the total gingival index from a mean of 2.25 before the intervention to 2 after the intervention (p-value = 0.003). Further details on the statistical analyses are provided in Table 3.

There was no significant difference in PI between the two groups before or after the intervention (p-value = 0.664 and p-value = 0.686, respectively). Similarly, there was no significant difference in PBI between the two groups before or after the intervention (p-value = 0.905 and p-value = 0.737, respectively). The reduction in average PBI and total gingival index between the two groups of chewing gum and mouthwash was not statistically significant.

According to the results of the Mann-Whitney test conducted on the variable of total gingival index, the median GI before intervention was found to be 2.25 in both the mouthwash and chewing gum groups. There was no statistically significant difference observed between the two groups (p-value = 0.937). After the intervention, the mean GI in both the mouthwash and chewing gum groups decreased to 2. The statistical analysis revealed that there was no significant difference in the gingival index after the intervention between the chewing gum and mouthwash groups (p-value = 1). Based on the results, both chewing gum and mouthwash have statistically the same effect in reducing plaque and bleeding from the gums.

This study aimed to evaluate the effectiveness of propolis-containing chewing gum versus propolis-containing mouthwash in reducing dental plaque, bleeding, and gingival inflammation in patients with gingivitis The study included 20 participants (14 women and 6 men) with gingivitis, selected from a student population to ensure balanced gender representation. Both interventions significantly reduced plaque index (PI), papillary bleeding index (PBI), and gingival index (GI), with no notable differences in effectiveness between the two groups. These findings align with previous studies, such as those by Nuray Ercan et al. (2015) [13] and Ell-Allaky et al. (2020) [22], which reported similar outcomes when comparing propolis-based products. The comparable efficacy of chewing gum and mouthwash highlights the versatility of propolis in various delivery formats.

Propolis demonstrated a plaque reduction of approximately 25–30%, comparable to or slightly less than chlorhexidine’s 30–35% reduction, as reported in studies such as Gonzalez et al. (2021) [23] and Nazeri et al. (2019) [14]. While chlorhexidine is often more effective in plaque reduction, its side effects, such as staining and taste alterations, make propolis a favorable alternative for long-term use, especially considering its additional antioxidant properties.

Chewing gum’s ease of use and ability to stimulate salivary flow make it a practical tool for oral health promotion, particularly for individuals seeking alternatives to traditional mouthwashes. Similarly, propolis-containing mouthwash offers an effective method for reducing plaque and gingival inflammation while avoiding the adverse effects associated with chemical-based rinses, such as chlorhexidine. Both interventions are suitable for managing gingivitis, particularly in cases where patient compliance or preferences play a significant role in treatment outcomes.

Although propolis is generally considered safe for short-term use; however, it can cause allergic reactions, particularly in individuals allergic to bee products. Symptoms may include swelling, redness, itching, or hives. Lozenges containing propolis have been associated with mouth irritation and ulcers. Long-term use of propolis may pose risks to liver and kidney health, as suggested by some studies [24].

To ensure consistency in clinical studies involving propolis, researchers should adopt standardized protocols for concentration and composition. Utilizing validated analytical techniques, such as high-performance liquid chromatography (HPLC), and adhering to international standards like ISO 24381:2023 can help minimize variability and enhance comparability across studies.

In summary, the findings from this study reinforce the potential of propolis-based products as viable options for the management of gingivitis. Further research should explore their long-term effects, compare them with other oral care products, and ensure consistency in propolis concentrations to minimize variability and enhance reliability.

Authors and Affiliations

1. Department of Periodontology, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

   Arezou Khabazian

2. DDS. Shahid Sadoughi University of Medical Sciences, Yazd, Iran

   Fatemeh sadat Mirhashemi

3. Postgraduate Student, Department of periodontology, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

   Faezeh Sadeghi

Contributions

AK was a principal investigator and a major contribution in conceptual framework, data collection, data entry, manuscript writing and literature search. FSM was a co-investigator assisted in selection of title, conceptual framework, design of study and manuscript writing. FS was a co-investigator assisted in selection of title, conceptual framework, design of study and manuscript writing. All authors read and approved the final version of the manuscript.

Corresponding author

Correspondence to Faezeh Sadeghi.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Ethics approval and consent to participate

This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. Ethical approval was obtained from the Ethics Committee of Shahid Sadoughi University of Medical Sciences under the code IR.SSU.REC1401.015, and the IRCT Registration code was IRCT20220420054592N1. It was retrospectively registered on 11/6/2022. After examination and diagnosis of periodontal symptoms, the necessary information was provided and written informed consent was obtained from all patients prior to their inclusion in the study.

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