Weighing up the potential of “superfoods” compounds of green tea or turmeric as adjuncts in comparison to established therapeutical approaches for periodontal disease
Periodontal disease, characterized by gingival inflammation, formation of gingival pockets, progressive attachment loss and bone loss , is estimated to affect a considerable portion of the world population with varying burden among different regions and populations . While bacterial plaque serves as the primary etiological factor in the development of gingivitis, which can progress to periodontitis, it is crucial to acknowledge that periodontal health is influenced by many factors, including genetic predisposition, systemic health, and nutritional status, which are recognized as key contributors . In the context of periodontal destruction, an intricate interplay emerges between the plaque biofilm and the host’s immunoinflammatory response, resulting in an imbalance between bacterial activity and the host’s defense mechanisms . When it comes to the treatment of periodontal disease, the initial therapeutic approach entails scaling and root planing (SRP) and has attained a prominent position as the standard treatment modality . Research in adjuncts for periodontal therapy has focused mainly on the use of antibiotics or antiseptics, both systemic and locally delivered, which has demonstrated notable efficacy in diminishing periodontal probing depths and thereby facilitating the restoration of clinical attachment levels and mitigation of the likelihood for subsequent attachment loss . Even though management of periodontitis entails mainly the removal of causal factors, the scope of possible factors that influence progression of tissue destruction or improve the outcome of therapy is large. The association between nutrition and periodontal health has been investigated in many studies, linking greater intakes of foods and nutrients with antioxidant and anti-inflammatory activity to a reduced risk of developing periodontal disease and improved periodontal healing . The potential benefits of so-called superfoods for tissues / processes also involved in periodontal health have gained considerable attention the last years. These include, among others, natural herbal products like chia seeds, quinoa, spirulina, turmeric, acai-berry, propolis, aloe vera, green tea, cranberry, calendula, myrrha and salvia . However, there is a lack of clear criteria for defining what qualifies as a superfood and which of them can be supported by ample clinical experimental evidence, in terms of better outcomes of periodontal treatment. Therefore, the present review aimed to evaluate the efficacy of the administration of “superfood” agents in patients who underwent non-surgical periodontal therapy, as compared to established treatment approaches and adjuncts. The initial focused question for this review was: is supplemental administration of specific superfoods associated with improved outcomes in the non-surgical treatment of periodontal disease (gingivitis or periodontitis) among human patients?   This review was conducted and reported in accordance with the Cochrane Handbook  and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement for systematic reviews , respectively. Eligibility criteria Included in this review were Randomized Clinical Trials (RCT) in humans of either parallel or within-person (split-mouth) randomization (i.e. local delivery of different agents at different sites within the mouth of the same patient), where one or more ‘superfoods’ were used as adjuncts in the treatment of periodontal disease (gingivitis or periodontitis). Superfoods should be used (alone or in combination with standard care) with a specific protocol and compared to a passive control group (no treatment, standard care or placebo) or an active control group consisting of chlorhexidine-containing products. Due to logistic constraints, included were only studies in English or German. Excluded were non-randomized studies, non-clinical studies, animal studies, in vitro studies, studies including patients with systemic diseases, and studies administering only isolated components or parts of a superfood. Information sources and search strategy A literature search was performed in MEDLINE through PubMed, Embase, Biosis Previews Database, and the Cochrane Library, using a separate search for each superfood and with the search covering from inception of each database to February 19th, 2024. Search terms consisted of the superfood combined with the keyword periodontitis and additionally with the MeSH terms antimicrobial and/or anti-inflammatory: (superfood) AND (“periodontitis”) AND (“anti-microbial” OR “anti-inflammatory”). The list of all superfoods that were used in the separate searches can be found in Appendix 2. Selection process Two authors (GH, MEK) independently screened titles and abstracts of the electronic search and assessed them in a first step for possible inclusion in the review, followed by assessment of their full text. Any disagreements between them were resolved by discussion with a third author (PRS). Included were only superfoods that were assessed by at least three studies in total, in order to provide more robust information. Data collection process and data items Data extraction was performed in duplicate by two independent authors (GH, MEK), stratified for gingivitis and periodontitis patients, and included: (i) study characteristics (design, setting, country); (ii) patient demographics (number, sex, age); (iii) superfood administered, including administration mode (mouthwash or local delivery); (iv) administration dosage and protocol; (v) control group used; (vi) duration of follow-up; and (vii) outcomes assessed. As studies on both gingivitis and periodontitis patients were included the Gingival Index (GI)  was set as the primary outcome, due to its relevance to both diseases. Secondary outcomes included the probing depth and any forms of the Plaque Index (PI), including among others those by Silness and Loe  or others . Risk of bias The risk of bias of all included studies was assessed with the Cochrane collaboration’s RoB 2 tool for randomized trials  by two independent authors (GH, MEK) and all disagreements were resolved again by discussion with a third person (PRS). The RoB 2 tool assesses the possible impact of bias (i) arising from the randomization process, (ii) due to deviations from intended interventions, (iii) due to missing outcome data, (iv) in measurement of the outcome, and (v) selection of the reported result. Synthesis methods Pairwise meta-analyses were used to synthesize data from two studies or more assessing the same comparison. The Mean Difference (MD) with its 95% Confidence Interval (CI) was chosen as effect measure for GI and probing depth, while the Standardized Mean Difference (SMD; Cohen’s d) was used to combine different PIs. As the effect of periodontal treatment was expected to vary according to several factors (including genetic predisposition, baseline severity, patient compliance, and individual biological response), a random-effects model with a restricted maximum likelihood variance estimator  was deemed a priori more appropriate to capture this variability and calculate the average distribution of associations across studies . Between-study heterogeneity was assessed through visual inspection of contour-enhanced forest plots (Appendix 1)  and through estimation of tau 2 (absolute heterogeneity) or I 2 (relative inconsistency) with their uncertainty intervals. 95% predictions were calculated, which incorporate identified heterogeneity and assist in the interpretation of the meta-analytical estimates by providing a range of expected effects across various future clinical settings . Random-effects subgroup analysis was used to assess differences between different administration modes (mouthwash or local delivery) for meta-analyses with at least 5 studies. Sensitivity analysis was performed for meta-analyses with ≥ 5 studies according to the study’s risk of bias. A sensitivity analysis was performed comparing the effects of active agents between reference groups of either control / placebo or standard treatment (Appendix 1). Analyses of reporting biases (including small-study effects and the possibility of publication bias) were planned to be assessed for meta-analyses with ≥ 10 studies (Appendix 1), but no such meta-analyses were ultimately performed. The Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was employed  to gauge the certainty around the results of meta-analyses and findings were presented with a revised summary of findings Table . All analyses were conducted in R 4.2.2. (R Foundation for Statistical Computing, Vienna, Austria) by one author (SNP), with open dataset , alpha set at 0.05 (except for between-subgroups where it was 0.10) and a two-sided P-value.   Included in this review were Randomized Clinical Trials (RCT) in humans of either parallel or within-person (split-mouth) randomization (i.e. local delivery of different agents at different sites within the mouth of the same patient), where one or more ‘superfoods’ were used as adjuncts in the treatment of periodontal disease (gingivitis or periodontitis). Superfoods should be used (alone or in combination with standard care) with a specific protocol and compared to a passive control group (no treatment, standard care or placebo) or an active control group consisting of chlorhexidine-containing products. Due to logistic constraints, included were only studies in English or German. Excluded were non-randomized studies, non-clinical studies, animal studies, in vitro studies, studies including patients with systemic diseases, and studies administering only isolated components or parts of a superfood.   A literature search was performed in MEDLINE through PubMed, Embase, Biosis Previews Database, and the Cochrane Library, using a separate search for each superfood and with the search covering from inception of each database to February 19th, 2024. Search terms consisted of the superfood combined with the keyword periodontitis and additionally with the MeSH terms antimicrobial and/or anti-inflammatory: (superfood) AND (“periodontitis”) AND (“anti-microbial” OR “anti-inflammatory”). The list of all superfoods that were used in the separate searches can be found in Appendix 2.   Two authors (GH, MEK) independently screened titles and abstracts of the electronic search and assessed them in a first step for possible inclusion in the review, followed by assessment of their full text. Any disagreements between them were resolved by discussion with a third author (PRS). Included were only superfoods that were assessed by at least three studies in total, in order to provide more robust information.   Data extraction was performed in duplicate by two independent authors (GH, MEK), stratified for gingivitis and periodontitis patients, and included: (i) study characteristics (design, setting, country); (ii) patient demographics (number, sex, age); (iii) superfood administered, including administration mode (mouthwash or local delivery); (iv) administration dosage and protocol; (v) control group used; (vi) duration of follow-up; and (vii) outcomes assessed. As studies on both gingivitis and periodontitis patients were included the Gingival Index (GI)  was set as the primary outcome, due to its relevance to both diseases. Secondary outcomes included the probing depth and any forms of the Plaque Index (PI), including among others those by Silness and Loe  or others .   The risk of bias of all included studies was assessed with the Cochrane collaboration’s RoB 2 tool for randomized trials  by two independent authors (GH, MEK) and all disagreements were resolved again by discussion with a third person (PRS). The RoB 2 tool assesses the possible impact of bias (i) arising from the randomization process, (ii) due to deviations from intended interventions, (iii) due to missing outcome data, (iv) in measurement of the outcome, and (v) selection of the reported result.   Pairwise meta-analyses were used to synthesize data from two studies or more assessing the same comparison. The Mean Difference (MD) with its 95% Confidence Interval (CI) was chosen as effect measure for GI and probing depth, while the Standardized Mean Difference (SMD; Cohen’s d) was used to combine different PIs. As the effect of periodontal treatment was expected to vary according to several factors (including genetic predisposition, baseline severity, patient compliance, and individual biological response), a random-effects model with a restricted maximum likelihood variance estimator  was deemed a priori more appropriate to capture this variability and calculate the average distribution of associations across studies . Between-study heterogeneity was assessed through visual inspection of contour-enhanced forest plots (Appendix 1)  and through estimation of tau 2 (absolute heterogeneity) or I 2 (relative inconsistency) with their uncertainty intervals. 95% predictions were calculated, which incorporate identified heterogeneity and assist in the interpretation of the meta-analytical estimates by providing a range of expected effects across various future clinical settings . Random-effects subgroup analysis was used to assess differences between different administration modes (mouthwash or local delivery) for meta-analyses with at least 5 studies. Sensitivity analysis was performed for meta-analyses with ≥ 5 studies according to the study’s risk of bias. A sensitivity analysis was performed comparing the effects of active agents between reference groups of either control / placebo or standard treatment (Appendix 1). Analyses of reporting biases (including small-study effects and the possibility of publication bias) were planned to be assessed for meta-analyses with ≥ 10 studies (Appendix 1), but no such meta-analyses were ultimately performed. The Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was employed  to gauge the certainty around the results of meta-analyses and findings were presented with a revised summary of findings Table . All analyses were conducted in R 4.2.2. (R Foundation for Statistical Computing, Vienna, Austria) by one author (SNP), with open dataset , alpha set at 0.05 (except for between-subgroups where it was 0.10) and a two-sided P-value.   Study selection From 1905 records identified from the electronic search, 1449 articles were excluded by title (Fig. ). Another 216 records were excluded by screening their abstracts, while a total of 74 full texts were assessed for eligibility (Appendix 2). Initially, the present study aimed to assess the effect of several superfood-based agents used adjunctly as mouthrinse or locally in the treatment of periodontal disease. However, from the 49 potentially eligible remaining studies, 30 studies were excluded as many superfood-based agents were used by less than 3 studies and precluded basic quantitative synthesis (meta-analysis). As such, the review’s scope was adapted post hoc to focus solely on green tea- or turmeric-containing agents used as adjuncts for the treatment of periodontal disease, and a total of 19 studies were ultimately included. Study characteristics Details of the included studies are given in Table , with ten of them assessing gingivitis patients and eight of them assessing periodontitis patients. From the ten studies on gingivitis, all of them were of parallel design and were conducted in a university clinic. The majority ( n = 8; 80%) of them were conducted in India, while one study was conducted in Iran and one in the United States. The average sample size was 48.2 patients/study, while patient sex was specified only in three (30%) of the studies (with 39.3% of patients being male). Six of the studies prescribed to the patients a mouthwash with green tea extract and four prescribed a turmeric mouthwash. Superfoods were most compared to a chlorhexidine mouthwash ( n = 9; 90%) and in two instances (20%) to a control / standard care group. Follow-up ranged from 1 to 12 weeks and all studies assessed both some kind of PI and GI. From the eight studies on periodontitis, the majority ( n = 5; 63%) employed a split-mouth design, all were conducted in university clinics, and the majority ( n = 6; 75%) originated from India. The average sample size was 30.3 patients/study and patient sex was reported in most ( n = 6; 75%) of studies (and 59.6% of patients being male). Half of the studies supplemented periodontitis treatment with green tea and the other half with turmeric—both administered locally. In all instances, superfoods supplementation was compared to standard care / placebo, while chlorhexidine control groups were used in two studies. Follow-up ranged from 4 to 28 weeks and probing depth was the most consistently reported outcome (in all studies). Risk of bias in studies The risk of bias of included trials with the RoB 2 tool is seen in Table and Appendix 5. Seven studies were found to be in low risk of bias, 2 studies showed some concerns, and the remaining 6 studies were in high risk of bias. The most problematic domains (at least to some extent) were bias due to deviations from the intended interventions (9 studies; 47%), followed by bias in measurement of the outcome (7 studies; 37%), and bias arising from the randomization process (1 study; 5%). Results of individual studies and data syntheses The results of all individual included studies can be found in the openly provided dataset of this review , while meta-analyses were used to combine data from ≥3 similar studies, separately for gingivitis (Table ) and periodontitis patients (Table ). As far as gingivitis is concerned, green tea mouthwash showed no statistically significant improvement compared to control / placebo in terms of PI (3 studies; SMD − 0.93; 95% CI -2.33 to 0.47; P = 0.19; Appendix 6) or GI (3 studies; MD -0.26; 95% CI -0.56 to 0.04; Appendix 7). Compared to a chlorhexidine mouthwash, green tea mouthwash showed no difference in terms of PI (5 studies; SMD − 0.28; 95% CI -0.82 to 0.26; P = 0.31; Appendix 8) but showed significantly smaller GI reduction (5 studies; MD 0.08; 95% CI 0.01 to 0.14; P = 0.01; Fig. ). The use of a turmeric mouthwash was not associated with significant differences compared to a chlorhexidine mouthwash in terms of PI (4 studies; SMD 0.28; 95% CI -0.53 to 1.10; P = 0.50; Appendix 9) or GI (4 studies; MD -0.03; 95% CI -0.10 to 0.04; P = 0.42; Appendix 10). For periodontitis patients, supplementation with local delivery of green tea extract was associated with greater reductions in PI (1 study; MD -0.85; 95% CI -1.08 to -0.62; P < 0.001), GI (3 studies; MD -0.53; 95% CI -1.01 to -0.05; P = 0.02; Fig. ), and probing depth (4 studies; MD -0.79 mm; 95% CI -1.29 to -0.29 mm; P = 0.002; Fig. ) compared to standard periodontal treatment. On the other side, turmeric supplementation did not show any significant improvements to standard periodontal treatment in terms of PI (4 studies; SMD − 0.49; 95% CI -1.74 to 0.75; P = 0.44; Appendix 11), GI (3 studies; MD -0.23; 95% CI -0.63 to 0.17; P = 0.25; Appendix 12), or probing depth (4 studies; MD -0.28 mm; 95% CI -0.77 to 0.21 mm; P = 0.26; Appendix 13). Similarly, turmeric supplementation was not associated with any differences compared to chlorhexidine use in terms of PI (2 studies; MD 0.07; 95% CI -0.09 to 0.23; P = 0.36; Appendix 14), GI (2 studies; MD 0.02; 95% CI -0.11 to 0.15; P = 0.78; Appendix 15), or probing depth (2 studies; MD 0.14; 95% CI -0.06 to 0.34; P = 0.17; Appendix 16). Additional analyses Subgroup analyses were planned to be performed according to administration mode for meta-analyses of ≥ 5 studies. This was the case for only two meta-analyses comparing green tea mouthwash to chlorhexidine mouthwash and assessing PI and GI (Table ). However, as only mouthwash was used in all instances, no such subgroup analysis was possible. Additionally, sensitivity analysis according to the risk of bias could not be performed for the same two meta-analyses, since all included studies in these were found to be in low risk of bias. Sensitivity analysis of meta-analyses on the absolute effect of green tea mouthwash did not find significant difference whether this was compared to control / placebo groups or standard treatment (scaling and root planning) (Appendix 17). The strength of meta-evidence was assessed with the GRADE approach for meta-analyses on gingivitis (Table ) and periodontitis patients (Table ). For the treatment of gingivitis (Table ), the strength of evidence was moderate to low for all non-significant meta-analyses due to inconsistency and imprecision. The significantly smaller reduction in GI of green tea mouthwash compared to chlorhexidine mouthwash was supported by evidence of moderate strength. For the treatment of periodontitis (Table ) the strength of evidence was low to very low in all instances due to bias and inconsistency.   From 1905 records identified from the electronic search, 1449 articles were excluded by title (Fig. ). Another 216 records were excluded by screening their abstracts, while a total of 74 full texts were assessed for eligibility (Appendix 2). Initially, the present study aimed to assess the effect of several superfood-based agents used adjunctly as mouthrinse or locally in the treatment of periodontal disease. However, from the 49 potentially eligible remaining studies, 30 studies were excluded as many superfood-based agents were used by less than 3 studies and precluded basic quantitative synthesis (meta-analysis). As such, the review’s scope was adapted post hoc to focus solely on green tea- or turmeric-containing agents used as adjuncts for the treatment of periodontal disease, and a total of 19 studies were ultimately included.   Details of the included studies are given in Table , with ten of them assessing gingivitis patients and eight of them assessing periodontitis patients. From the ten studies on gingivitis, all of them were of parallel design and were conducted in a university clinic. The majority ( n = 8; 80%) of them were conducted in India, while one study was conducted in Iran and one in the United States. The average sample size was 48.2 patients/study, while patient sex was specified only in three (30%) of the studies (with 39.3% of patients being male). Six of the studies prescribed to the patients a mouthwash with green tea extract and four prescribed a turmeric mouthwash. Superfoods were most compared to a chlorhexidine mouthwash ( n = 9; 90%) and in two instances (20%) to a control / standard care group. Follow-up ranged from 1 to 12 weeks and all studies assessed both some kind of PI and GI. From the eight studies on periodontitis, the majority ( n = 5; 63%) employed a split-mouth design, all were conducted in university clinics, and the majority ( n = 6; 75%) originated from India. The average sample size was 30.3 patients/study and patient sex was reported in most ( n = 6; 75%) of studies (and 59.6% of patients being male). Half of the studies supplemented periodontitis treatment with green tea and the other half with turmeric—both administered locally. In all instances, superfoods supplementation was compared to standard care / placebo, while chlorhexidine control groups were used in two studies. Follow-up ranged from 4 to 28 weeks and probing depth was the most consistently reported outcome (in all studies).   The risk of bias of included trials with the RoB 2 tool is seen in Table and Appendix 5. Seven studies were found to be in low risk of bias, 2 studies showed some concerns, and the remaining 6 studies were in high risk of bias. The most problematic domains (at least to some extent) were bias due to deviations from the intended interventions (9 studies; 47%), followed by bias in measurement of the outcome (7 studies; 37%), and bias arising from the randomization process (1 study; 5%).   The results of all individual included studies can be found in the openly provided dataset of this review , while meta-analyses were used to combine data from ≥3 similar studies, separately for gingivitis (Table ) and periodontitis patients (Table ). As far as gingivitis is concerned, green tea mouthwash showed no statistically significant improvement compared to control / placebo in terms of PI (3 studies; SMD − 0.93; 95% CI -2.33 to 0.47; P = 0.19; Appendix 6) or GI (3 studies; MD -0.26; 95% CI -0.56 to 0.04; Appendix 7). Compared to a chlorhexidine mouthwash, green tea mouthwash showed no difference in terms of PI (5 studies; SMD − 0.28; 95% CI -0.82 to 0.26; P = 0.31; Appendix 8) but showed significantly smaller GI reduction (5 studies; MD 0.08; 95% CI 0.01 to 0.14; P = 0.01; Fig. ). The use of a turmeric mouthwash was not associated with significant differences compared to a chlorhexidine mouthwash in terms of PI (4 studies; SMD 0.28; 95% CI -0.53 to 1.10; P = 0.50; Appendix 9) or GI (4 studies; MD -0.03; 95% CI -0.10 to 0.04; P = 0.42; Appendix 10). For periodontitis patients, supplementation with local delivery of green tea extract was associated with greater reductions in PI (1 study; MD -0.85; 95% CI -1.08 to -0.62; P < 0.001), GI (3 studies; MD -0.53; 95% CI -1.01 to -0.05; P = 0.02; Fig. ), and probing depth (4 studies; MD -0.79 mm; 95% CI -1.29 to -0.29 mm; P = 0.002; Fig. ) compared to standard periodontal treatment. On the other side, turmeric supplementation did not show any significant improvements to standard periodontal treatment in terms of PI (4 studies; SMD − 0.49; 95% CI -1.74 to 0.75; P = 0.44; Appendix 11), GI (3 studies; MD -0.23; 95% CI -0.63 to 0.17; P = 0.25; Appendix 12), or probing depth (4 studies; MD -0.28 mm; 95% CI -0.77 to 0.21 mm; P = 0.26; Appendix 13). Similarly, turmeric supplementation was not associated with any differences compared to chlorhexidine use in terms of PI (2 studies; MD 0.07; 95% CI -0.09 to 0.23; P = 0.36; Appendix 14), GI (2 studies; MD 0.02; 95% CI -0.11 to 0.15; P = 0.78; Appendix 15), or probing depth (2 studies; MD 0.14; 95% CI -0.06 to 0.34; P = 0.17; Appendix 16).   Subgroup analyses were planned to be performed according to administration mode for meta-analyses of ≥ 5 studies. This was the case for only two meta-analyses comparing green tea mouthwash to chlorhexidine mouthwash and assessing PI and GI (Table ). However, as only mouthwash was used in all instances, no such subgroup analysis was possible. Additionally, sensitivity analysis according to the risk of bias could not be performed for the same two meta-analyses, since all included studies in these were found to be in low risk of bias. Sensitivity analysis of meta-analyses on the absolute effect of green tea mouthwash did not find significant difference whether this was compared to control / placebo groups or standard treatment (scaling and root planning) (Appendix 17). The strength of meta-evidence was assessed with the GRADE approach for meta-analyses on gingivitis (Table ) and periodontitis patients (Table ). For the treatment of gingivitis (Table ), the strength of evidence was moderate to low for all non-significant meta-analyses due to inconsistency and imprecision. The significantly smaller reduction in GI of green tea mouthwash compared to chlorhexidine mouthwash was supported by evidence of moderate strength. For the treatment of periodontitis (Table ) the strength of evidence was low to very low in all instances due to bias and inconsistency.   Evidence in context The present systematic review summarizes data from 19 randomized trials on 814 human patients using green tea extract or turmeric for the treatment of gingivitis and periodontitis. Evidence from included studies indicated that neither green tea nor turmeric conferred significant benefits for the treatment of gingivitis. As far as periodontitis treatment is concerned, the use of green tea was associated with significant benefits in terms of improved periodontal parameters, while no such indications were seen for turmeric. Treatment of plaque-induced gingivitis was not found to benefit from supplemental administration of either green tea extract or turmeric through mouthwashes. On the contrary, green tea mouthwash was associated with smaller GI reduction than chlorhexidine mouthwash (Table ), the efficacy of which has long since been proven . Green tea extracts in mouthwashes have previously been shown to be effective in reducing plaque scores . Periodontitis treatment was enhanced through the topical application of green tea extract in terms of improved probing depth, gingival inflammation, and plaque control (Table ). Catechins in general possess anti-oxidant, anti-carcinogenic, anti-inflammatory, and anti-microbial properties  and green tea catechins have been shown to inhibit the growth of certain periodontal pathogens like P. gingivalis  and T. forsythia . Green tea catechins have been shown to also possess anti-collagenase properties, which might aid in preventing bone resorption and lead to greater probing depth reduction . They might also reduce potential periodontal breakdown through their inhibition of the cysteine proteinases of P. gingivalis and the protein tyrosine phosphatase of P. intermedia , which are considered periodontal virulence factors. In this systematic review, studies evaluating the effects of a professional application of components of superfoods on the response to periodontal treatment were critically appraised. Several decisions had to be taken at the beginning of this review, as no universally accepted definition exists for so-called “superfoods” . The term “superfood” suggests usually foods rich in macro- and micronutrients, which might have positive effects on human health or might contribute to disease prevention and / or treatment . However, the concept of superfoods in terms of food or beverages consumed through a patient’s nutrition limits the scope of experimental intervention in a controlled clinical setting, where we can ensure that the application is made by trained clinicians under controlled conditions. For this reason, this review focused post hoc on the experimental administration of two selected superfoods (green tea and turmeric) in the controlled environment of human intervention trials, where a concise administration protocol can be employed and replicated. Limitations The present review has several limitations. First, only studies in English or German were included and this might introduce language bias . The majority of included studies originated from specific parts of the world (mostly from India) and therefore their results need to be confirmed by independent studies from different regions. Additionally, large variation existed in used administration protocols, and it was not possible to identify the most efficient protocol in each case. Several included studies had limited sample sizes and this leads to evidence of imprecision in the GRADE approach . Finally, several included studies were found to be in high risk of bias, which has been shown to sometimes influence their effect estimates . Future studies should actively compare different concentrations or administration methods, include an adequate sample size based on appropriate a priori calculations, follow contemporary guidelines for their conduct / reporting , have an a priori registration / protocol , and ensure open data provision to increase transparency .   The present systematic review summarizes data from 19 randomized trials on 814 human patients using green tea extract or turmeric for the treatment of gingivitis and periodontitis. Evidence from included studies indicated that neither green tea nor turmeric conferred significant benefits for the treatment of gingivitis. As far as periodontitis treatment is concerned, the use of green tea was associated with significant benefits in terms of improved periodontal parameters, while no such indications were seen for turmeric. Treatment of plaque-induced gingivitis was not found to benefit from supplemental administration of either green tea extract or turmeric through mouthwashes. On the contrary, green tea mouthwash was associated with smaller GI reduction than chlorhexidine mouthwash (Table ), the efficacy of which has long since been proven . Green tea extracts in mouthwashes have previously been shown to be effective in reducing plaque scores . Periodontitis treatment was enhanced through the topical application of green tea extract in terms of improved probing depth, gingival inflammation, and plaque control (Table ). Catechins in general possess anti-oxidant, anti-carcinogenic, anti-inflammatory, and anti-microbial properties  and green tea catechins have been shown to inhibit the growth of certain periodontal pathogens like P. gingivalis  and T. forsythia . Green tea catechins have been shown to also possess anti-collagenase properties, which might aid in preventing bone resorption and lead to greater probing depth reduction . They might also reduce potential periodontal breakdown through their inhibition of the cysteine proteinases of P. gingivalis and the protein tyrosine phosphatase of P. intermedia , which are considered periodontal virulence factors. In this systematic review, studies evaluating the effects of a professional application of components of superfoods on the response to periodontal treatment were critically appraised. Several decisions had to be taken at the beginning of this review, as no universally accepted definition exists for so-called “superfoods” . The term “superfood” suggests usually foods rich in macro- and micronutrients, which might have positive effects on human health or might contribute to disease prevention and / or treatment . However, the concept of superfoods in terms of food or beverages consumed through a patient’s nutrition limits the scope of experimental intervention in a controlled clinical setting, where we can ensure that the application is made by trained clinicians under controlled conditions. For this reason, this review focused post hoc on the experimental administration of two selected superfoods (green tea and turmeric) in the controlled environment of human intervention trials, where a concise administration protocol can be employed and replicated.   The present review has several limitations. First, only studies in English or German were included and this might introduce language bias . The majority of included studies originated from specific parts of the world (mostly from India) and therefore their results need to be confirmed by independent studies from different regions. Additionally, large variation existed in used administration protocols, and it was not possible to identify the most efficient protocol in each case. Several included studies had limited sample sizes and this leads to evidence of imprecision in the GRADE approach . Finally, several included studies were found to be in high risk of bias, which has been shown to sometimes influence their effect estimates . Future studies should actively compare different concentrations or administration methods, include an adequate sample size based on appropriate a priori calculations, follow contemporary guidelines for their conduct / reporting , have an a priori registration / protocol , and ensure open data provision to increase transparency .   Evidence from randomized trials on humans failed to find any significant benefits from the use of mouthwashes containing green tea extract or turmeric for the treatment of gingivitis. Local supplementation with green tea extract during periodontitis treatment was found to be associated with improved outcomes in terms of probing depth, gingival index, and plaque index. On the other hand, local supplementation with turmeric was not found to be associated with improved outcomes of periodontitis treatment. However, no strong clinical recommendation can be made, due to the small number and high risk of bias of existing studies and additional research is needed.   Below is the link to the electronic supplementary material. Supplementary Material 1   