1. Context
The oral cavity contains 500 - 1000 different types of bacteria, fungi, and occasional viruses (1). Cleaning the oral cavity is an essential method of preserving oral health due to removing microbial plaques and preventing them from accumulating on gingiva (2). Periodontal diseases can affect almost 90% of the population. Several etiologic factors can lead to periodontal diseases, including the accumulation of dental plaques (3). In addition to periodontal diseases, plaque is a critical factor for the initiation and progression of dental caries (4).
Tooth brushing once a day is almost adequate to remove plaques and prevent the onset of gingivitis and caries (5). However, the average adult population do not adhere to sufficient tooth brushing. Consequently, some compounds, such as chlorhexidine, have been used as mouth rinses or are added to toothpaste as adjunctives to improve the mechanical plaque removal (6). Toothpaste can efficiently deliver therapeutically active agents like fluoride to the surface of the teeth (7). The success of toothpaste depends on its ability to reduce pathogenic oral microflora (8). Researchers have investigated more appropriate alternatives for traditional dental medicines due to side effects. For instance, the unpleasant taste and staining are the main side effects of chlorhexidine mouthwashes (9).
The use of natural products in the treatment of oral conditions has recently increased. Among these herbal products, Aloe vera is a frequently used plant (10). Aloe vera is a tropical plant grown in a hot and dry climate. It is commonly found in the Northeast of Brazil under the name ‘Barbosa’ (11, 12). Aloe vera gel consists of about 98% water. The remaining include active compounds such as carvacrol, thymol, linalool, phenylmethyl ester, normethadone (an anti-inflammatory compound), fenretinide, and other active natural compounds, such as anthraquinones, vitamins, amino acids, saponins, sugars, and lignin (13). One of the advantages of herbal medicines is that their long-term usage decreases the side effects of traditional drugs (14). As mentioned above, A. vera contains acemannan and anthraquinone, which are anti-microbial and antiseptic substances. No adverse side effects have been attributed to A. vera, making it a suitable alternative for dental plaque control (15, 16). Herbal toothpaste such as A. vera have been used for many years due to its effect on oral diseases, including oral cancerous and precancerous lesions (17). The amount of A. vera in a dentifrice usually ranges from 0.4 to 10%. It is proven that dentifrices with a higher concentration of A. vera have higher anti-microbial effects (18). The advantages of herbal toothpaste include a more pleasant taste, prevention of caries formation, and freshening the breath. Researchers have also reported that A. vera toothpaste showed significant improvement in reducing plaque accumulation (15).
The usage of A. vera includes evidence-based and tradition-based approaches. The use of this plant for wound healing, mucositis, acne vulgaris, genital herpes, diabetes type II, and HIV infection is considered evidence-based usage; however, the tradition-based usage is not thoroughly tested, and it includes the use of A. vera for alopecia, bacterial and fungal skin infections, systemic lupus erythematosus, and arthritis (12).
Studies have reported the effect of A. vera mouthwash on plaque formation and gingivitis, and A. vera has been suggested as a substitute alternative for chlorhexidine mouthwash (19). The results of a study showed that the anti-microbial activity of A. vera toothpaste could inhibit the growth of Streptococcus sanguinis. Despite the wide distribution of herbal toothpaste, information about the anti-microbial effects and compounds of different commercial toothpaste is still limited (20). This study aimed to investigate the clinical impact of A. vera as an active ingredient in toothpaste formulations.
2. Evidence Acquisition
2.1. Search Strategy
The data used in the present review were obtained from articles published until September 2020. The search was performed using the following keywords: “Aloe vera”, “toothpaste”, and “dentifrice”. All the related articles were retrieved from the Google Scholar, Scopus, Ovid, PubMed, and Science Direct databases and documents published from different international institutions. The search was restricted to articles published in English.
2.2. Inclusion and Exclusion Criteria
The inclusion criteria were: (1) English-language articles with detailed information regarding A. vera toothpaste and its clinical effects.
The exclusion criteria were: (1) case reports, (2) animal studies, (3) medical record reviews, (4) meeting abstracts, (5) historical articles, (6) editorials, (7) letters, and (8) commentaries.
2.3. Screening and Selection
Out of 15 articles related to the mentioned topic, 12 articles met the inclusion criteria. Topics discussed in this review included health care, A. vera, its applications, herbal toothpaste, and their clinical effects. Two reviewers independently screened the titles and abstracts of the related articles, and if determined eligible, the full texts were obtained for further reading.
3. Results
3.1. Study Selection
A total of 383 articles were identified by searching the mentioned databases based on the strategy outlined in the materials and methods section. Duplicate manuscripts were removed. Subsequently, the full texts of 13 articles were reviewed, out of which only one paper was excluded due to inaccessibility through official web pages (21) (Figure 1).
Search and selection of the primary studies
3.2. Features of Included Studies
Out of the 12 studies included, seven studies were clinical trials, three were in vitro, one was in vivo, and one was a systematic review of A. vera dentifrices effects on dental plaque and gingivitis.
3.3. Clinical Outcomes of Studies Included
3.3.1. Clinical Trials
Among the seven clinical trials, five articles analyzed the effects of A. vera on periodontal indices. All these five articles showed that A. vera had no additional effects on plaques and gingivitis compared to other control toothpaste mentioned in these trials (15, 22-25). The results of these seven clinical trials are reported in Table 1.
| First Author (Year) | Study Population | Clinical Evaluations | Study Groups | Results |
|---|---|---|---|---|
| Namiranian and Serino (2012) (23) | 15 subjects | Plaque Index (PI) and Gingival Index (GI) | In the first six months, the patient's own toothpaste was used. In the second six months, A. vera toothpaste, and in the third six months, the control toothpaste was used. | The use of a toothpaste containing A. vera showed no additional effect on plaques and gingivitis compared to control toothpaste. |
| Pradeep et al. (2012) (15) | 90 subjects | PI and GI and microbiological counts | Group 1: placebo toothpaste; Group 2: toothpaste containing A. vera; Group 3: toothpaste containing triclosan and fluoride. | There was no significant difference between the A. vera –containing toothpaste and the toothpaste containing triclosan in the reduction of PI and GI indices. Natural herbal preparations in oral health care are still popular, and A. vera dentifrice can be considered a useful adjunct. Its efficacy is comparable to toothpaste containing triclosan. |
| Garnick et al. (1994) (26) | 79 subjects | Changes in root sensitivity | Group 1: placebo toothpaste; Group 2: toothpaste containing A. vera; Group 3: toothpaste containing allantoin; Group 4: toothpaste containing allantoin and A. vera. | All four kinds of toothpaste reduced root sensitivity, but the difference between the groups was not statistically significant. |
| Suthar et al. (2017) (25) | 60 subjects | PI, GI, SBI, and OHI | Group 1: A. vera toothpaste; Group 2:fluoridated toothpaste (Colgate®). | There was no significant difference between the A. vera and conventional groups. Still, it can be concluded that A. vera toothpaste might be a useful plaque control agent in patients with gingivitis. |
| Chandhru et al. (2020) (27) | 60 children | Antifungal activity against Candida albicans | Six groups with six different commercial children toothpaste, including Aloe-dent toothpaste | Among these six kinds of toothpaste, Aloe Dent children's toothpaste® showed the minimum antifungal activity. |
| de Oliveira et al. (2008) (24) | 30 subjects | PI and GBI | The test group used A. vera dentifrice and the control group used fluoridated dentifrice | The dentifrice containing A. vera did not show any additional effects on dental plaque and gingivitis reduction compared to the fluoridated dentifrice. |
| Kripal et al. (2014) (22) | 45 subjects | Probing Pocket Depth (PPD), GI, and PI | Group 1: scaling alone; Group 2: scaling and A. vera toothpaste; Group 3: A. vera toothpaste alone. | There was a significant reduction in the PI and GI indices at the baseline during the fourth and sixth weeks across all the groups. A. vera can be used as an adjunct to scaling (oral prophylaxis) to improve clinical parameters (PI, GI, BOP). |
Results of Primary Clinical Studies
3.3.2. In Vitro Studies
Three in vitro studies related to A. vera toothpaste were reviewed in the present literature review. All these three articles analyzed the effect of A. vera against Streptococcus mutans. Two of them showed that A. vera had advantages in decreasing the accumulation of this micro-organism on teeth (20, 28). Still, George et al. concluded that A. vera toothpaste had an equal effect in controlling S. mutans and other organisms compared to other commercial toothpaste (8). The results are shown in Table 2.
| First Author (Year) | Study Method | Clinical Evaluations | Study Groups | Results |
|---|---|---|---|---|
| Korkmaz et al. (2019) (20) | Agar disk diffusion method | Anti-microbial Efficacy against S. mutans and S. aureus | Three herbal toothpastes containing A. vera and strawberry extract | The herbal toothpastes could have advantages in decreasing bacterial accumulation on teeth with additional oral cavity protection. |
| George et al. (2009) (8) | Freeze-dried stock culture | Anti-microbial Efficacy against S. mutans, S. mitis, Candida albicans, Enterococcus fecalis, and PI | A. vera tooth gel, Pepsodent toothpaste, and Colgate toothpaste | A. vera tooth gel was as effective as two commercially popular toothpaste in controlling all the organisms used in the study. |
| Bertolini et al. (2012) (28) | 15 sterile toothbrushes | The anti-microbial capacity of A. vera and propolis dentifrice against Streptococcus mutans strains in toothbrushes | Five groups including negative control group without dentifrice, fluoridated dentifrice, triclosan dentifrice, positive control without dentifrice and irrigation, A. vera, and propolis dentifrice | After tooth brushing, the A. vera and propolis dentifrice group reduced the contamination of toothbrush bristles by S. mutans, without additional differentiation from the formal chemical agents used in toothpaste. |
Results of in Vitro Primary Studies
3.3.3. In Vivo Studies
Among the 12 primary studies in our review, only one study was an in vivo study in which the anti-microbial effect of A. vera and two other toothpastes against S. mutans was analyzed by collecting patients’ saliva after two days, 15 days, and 30 days of brushing. The saliva specimens were cultured. The results comparing A. vera to two other toothpaste were not statistically significant (Table 3) (1).
| First Author (Year) | Study Population | Clinical Evaluations | Study Groups | Results |
|---|---|---|---|---|
| Bhati et al. (2015) (1) | 60 children | Anti-microbial efficacy using mitis agar for determining S. mutans count | Group 1: control; Group 2: fluoridated dentifrice; Group 3: herbal dentifrice containing A. vera; Group 4: Herbal dentifrice containing Dabur miswak. | No significant difference was observed in the anti-microbial properties of all the three test dentifrices, but they recommended A. vera as an alternative to fluoridated dentifrice for children. |
Results of in Vivo Primary Studies
4. Discussion
This review aimed to compare the effects of A. vera as an active ingredient in toothpaste to other kinds of toothpaste. As mentioned above, plaque is a primary risk factor in periodontal diseases, and the removal of plaque can prevent the occurrence of these diseases. The use of mechanical methods and chemotherapeutic agents is the existing ways to maintain oral health (2). Among mechanical methods, brushing and flossing are the most common methods (29). However, nowadays, compliance with plaque control and brushing has decreased. Mechanical methods of plaque control are time-consuming. Some individuals lack the motivation to improve the efficacy of self-performed mechanical procedures; thus, positive changes that may lead to improved daily plaque control seem necessary. Therefore, compounds such as herbal agents have been added to toothpastes (30, 31). Studies report an increasing demand for treatment options for oral diseases using natural products that are safe and effective. Nowadays, bacteria have become resistant to antibiotics. Furthermore, the antibacterial agents commonly used in dentistry have several adverse side effects. Using herbal dentifrices is an alternative option evaluated in clinical trials for controlling dental plaque and periodontal diseases (32, 33). Recently, the use of A. vera as a dentifrice has gained importance, and due to its useful properties, it is considered an ideal choice for microbial plaque control (22). Studies have shown that herbal toothpaste exhibit much safer and better anti-microbial activities compared to synthetic ones (34).
Aloe vera is a member of the Asphodelaceae family and has different types, but A. barbadensis is mostly used in dentistry due to its medicinal properties (8). The main compounds of A. vera are carvacrol, thymol, linalool, phenylmethyl ester, normethadol, and fenretinide. Also, it has different active natural compounds, like anthraquinones, vitamins, amino acids, saponins, sugars, and lignin. Due to the existence of these compounds, A. vera has antiviral, antibacterial, and anti-inflammatory activities (12, 20). The level of these compounds differs based on the strain and growth condition of the plant (13).
Aloe vera gel has been used for health care goals due to its anti-inflammatory and anti-microbial effects. Aloe vera also contains acemannan, which has anti-microbial and antifungal effects and can stimulate antibody production by the immune system (28).
The present study's findings indicated that A. vera dentifrices have anti-microbial effects like other commercial toothpaste. This review showed that A. vera is effective in reducing periodontal indices and bacterial accumulation. Seven clinical trials evaluated the potential of A. vera toothpaste in the maintenance of oral health, five of which reported that A. vera was as effective as other toothpaste they tested and the difference between them was not significant. This finding is inconsistent with the results of an in vivo study conducted by Bhati et al., who showed that herbal toothpaste containing A. vera had almost the same anti-microbial effects as fluoridated toothpaste and control toothpaste (1). The other two clinical studies showed different results. Chandhru et al. (27) concluded that although A. vera toothpaste has antifungal activity, its antifungal activity was less than other commercial ones used by children. The antifungal activity of A. vera toothpaste was due to its active ingredients such as anthraquinone. Still, the reason for its minimal antifungal activity compared to others can be related to inappropriate dilutions and testing methods.
A systematic study by Dhingra investigated two clinical trials reviewed in the present study. They also reported that A. vera toothpaste had no significant effects compared to control groups. Still, both of the RCT studies they reviewed reported no adverse effects and had good patient acceptance (35).
The anti-microbial capacity of A. vera dentifrice against S. mutans inside toothbrush bristles was reviewed in an in vitro study by Bertolini et al. (28). They observed that the dentifrice containing A. vera reduced the contamination of bristles by S. mutans but without significant difference compared to the other groups. These results are also consistent with the findings of those five trials mentioned above.
Kripal et al. conducted a randomized clinical trial on the clinical effects of commercial toothpaste containing A. vera in 45 subjects. Their results were contrary to other primary studies. They concluded that reduction in periodontal indices, such as bleeding on probing (BOP) and gingival index (GI), were higher in the group that used A. vera toothpaste as an adjunctive treatment in addition to scaling (22). A higher concentration of A. vera has a better effect as a phytotherapeutic agent (36). Thus, one of the reasons for different results in this study can be the difference in the percentage of A. vera in the total formulation of the toothpaste.
Also, the anti-microbial efficacy of A. vera dentifrice against S. mutans in a culture medium was reviewed in two of the primary studies. The results of these two studies were different. George et al. (8) showed that A. vera was equally effective as two other commercial toothpastes, but the A. vera toothpaste had an increased antibacterial effect against S. mitis. Moreover, this study reported that the anti-microbial effects of commercial toothpaste were due to the fluoride in their formulation. Although A. vera dentifrice has no fluoride, it has antibacterial effects against different organisms due to its active compounds, which are equal to other toothpaste. Another in vitro study by Korkmaz et al., which compared an A. vera toothpaste and an herbal toothpaste containing strawberry extract by agar diffusion test, reported that the A. vera toothpaste had a higher anti-microbial effect against S. mutans than the other herbal toothpaste. This study showed that oxygenated monoterpenes such as menthol in A. vera are responsible for their anti-microbial activity. They concluded that herbal toothpaste have several advantages in reducing bacterial accumulation (20).
Besides the primary studies’ results in this article, A. vera gel has been used to heal aphthous ulcers and lichen planus lesions. It has bactericidal effects against S. mutans and Porphyromonas gingivalis (37). Furthermore, A. vera inhibits the formation and accumulation of plaques and the growth of micro-organisms; thus, it is ideal for treating gingivitis and oral infections (1). Aloe vera toothpaste can effectively reduce gingival and plaque index (PI) scores. The reduction in PI is due to the antibacterial properties of A. vera, and the reduction of GI is attributed to sterols as anti-inflammatory agents. Further, the carboxypeptidase in A. vera inactivates bradykinin and reduces prostaglandin synthesis leading to the reduction of inflammation and pain (25).
This review has some limitations, including lack of sufficient clinical studies, difference in the concentration of A. vera in toothpaste formulations, different methods of testing, and various control groups.
Also, most of the studies evaluated periodontal indices and the reduction of organisms, including S. mutans. Therefore, it is suggested to conduct further studies on the effects of A. vera toothpaste and examine other clinical dental parameters.
5. Conclusions
Aloe vera toothpaste had similar clinical effects compared to other commercial toothpaste. It can be used as an adjunct formulation due to its herbal and medicinal properties and its established effects on improving periodontal problems and reducing different oral cavity micro-organisms.
