Located to the north of the Municipality of Za-Kpota, the District of Kpakpamè is one of the eight (08) administrative subdivisions that make up the Municipality of Za-Kpota. It is between the parallels 7˚14'27'' and 7˚20'30'' north latitude and then between 2˚05'09'' and 2˚14'27'' east longitude. It covered a population of 15.327 inhabitants in 2013 with an area of 230 km². This district is made up of seven (07) villages: Kpakpamè, Somè, Dramè, Mlinkpin-guingni, Tangbé, Affossowogba, and Davègo ( Akpohê, 2018: p. 22 ). The capital of this district is the village of Kpakpamè ( Figure 1 ).

Kpakpamè has a subequatorial climate characterized by two rainy seasons and two dry seasons ( Akpohê, 2018: p. 26 ). The annual rainfall average varies between 900 and 1000 mm. This climate is favorable for the growth of plant species in general and those used as brush in particular. The research area belongs to the coastal sedimentary basin zone. The relief as a whole is not very rugged and dominated by plateaus with an altitude varying between 20 and 200 m. However, elevations with some rocky outcrops are observed in the Kpakpamè District. The village of Togadji is also the seat of outcrops of magmatic rock with vertical outlets of the earth from the rock in places similar to human construction. The same goes for the arrangement of the blocks of rock on top of each other. Nature itself has carved the rock with various shapes. But, this rock disintegrates with detachments of blocks, and cracks in the rock allowing the emergence of saxicolous vegetation ( Delvaux et al., 2009: p. 708 ). This relief favors the growth of several plant species including those used as plant brush in the Kpakpamè District. The vegetation is characterized by a savannah, which experiences a fair amount of anthropogenic pressure, in particular the mosaics of crops and fallows which can be under palm trees, the zones of tree and shrub savannah. However, this plant formation is very populated by species such as Daniellia Oliveri, Adansonia digitata, Vitex doniana, Ceiba pentandra, Parkia biglobosa, etc. Some other species such as Lophira lanceolata, Vitellaria paradoxa, Prosopis africana, and Anogeissus leiocarpa in the research sector where most are used as plant brushes in the treatment of oral hygiene.

The data used are of two types (qualitative and quantitative) and collected either from existing literature (documentary research) or from fieldwork.

Surveys are carried out in all villages in the Kpakpamè District. Thus, the sample was determined by the formula of Schwartz (1995) :

N = Zα²PQ/d²

with: N is the sample size per district; Zα is the difference set at 1.96 and corresponds to a confidence level of 95%; P is the number of households in the village divided by the total number of households in the District; Q is the difference of one and P (Q = 1 − P); d is the margin of error which is equal to 5%. Table 1 shows the distribution of the sample by village.

Source: Fieldwork, August 2023.

In total, one hundred and ninety-five (195) people were identified and investigated.

To achieve the objective of this research, an identification sheet of plant species used as toothbrush was designed based on previous studies carried out by other authors, an ethnobotanical and oral survey sheet to know the different uses and virtues of the species and a GPS to take the geographical coordinates of the points of presence of the inventoried plant species were used.

The different data collection techniques focused on direct observations made to identify the species used as toothbrush plants; the questionnaire survey for the collection of species recognized and used by each person surveyed to obtain precision on the species used as toothbrush plants.

Regarding the information relating to the therapeutic values of the species used as toothbrush plants, the interview in the local Fon language was the technique used. It was supported by focus groups with herbalists, in this case the sellers of the organs of the plant species in the Kpakpamè district. Endogenous knowledge was the main basis of this research given that the study was carried out in a very rural environment with an illiteracy rate of 90% but which is home to a large number of herbalists with quality endogenous knowledge.

After listing the plant brush species, the scientific names were first identified using the analytical flora of Akoègninou et al. (2006) . The following parameters were calculated. These include:

This value is calculated to know the number of times the part of a plant is cited (Px) divided by the total number of times all parts are cited (Pt).

CPP = Px/Pt ( Koura et al., 2011: p. 10 )

To determine the most frequent collection sites, the consensus value for collection sites from ( Monteiro et al., 2006: p. 5 ) is calculated. The consensus value for collection sites is calculated as follows:

SCC = Sx/St

with Sx: the number of times a collection site is cited; St: the total number of collection site citations. QGIS 2.18 software was used to create the situation map.

Nineteen (19) plant species divided into nineteen (19) genera and eleven (11) families are used as plant toothbrushes in the Kpakpamè District ( Table 2 ).

Source: Survey results, August 2023.

Figure 2 shows the distribution of species used as plant brushes in the Kpakpamè District according to their botanical family. Eleven (11) botanical families are presented in this figure. The most represented families are Meliaceae (30.43%), Fabaceae (28.26%), and Rutaceae (14.13%). On the other hand, Moringaceae (1.09%) and Myrtaceae (2.17%) are the least dominant. These plant species used as plant-based toothbrushes are exploited by the Fon (84%), Adja (3%), Mahi (6%), Peuhl (2%), and other ethnic groups (5%). Furthermore, among the species inventoried, some are mentioned more than others. This demonstrates their great usefulness in the care of oral treatment and other illnesses in the district.

Table 3 presents the frequency of citation of species.

Source: Fieldwork, August 2023.

From Table 3 , it appears that of the 19 species cited by the populations, only Pseudocedrella kostchyi and Zanthoxylum zanthoxyloides are more used as plant brushes with a respective citation frequency of 0.27 and 0.14. Plate 1 presents these species.

According to the surveys, the people surveyed (100%) declared that they often used Pseudocedrela kostchyi to treat tooth decay, constipation, and cough, and Zanthoxylum zanthoxyloides to also treat tooth decay and stomach aches.

Source: Fieldwork, August 2023.

It emerges from the analysis of Table 6 that the species used as plant brush come from six places namely: village lands, Togadji, market, Davègo, farm, and house.

In the Kpakpamè District, it has been indicated that plant species used as brushes are used to treat certain conditions. Table 7 shows the different species used as plant brushes which are used in traditional medicine.

Source: Field survey, August 2023.

From the analysis of Table 7 , it appears that eighteen (18) plant species are used as brushes and to cure certain pathologies such as dental caries, teething problems, gingivitis, malaria, stomach aches, coughs, toothaches, etc. The usages identified during this study are: brushing teeth, decoction, and infusion, chewing and swallowing the juice, gargling, and drinking. The different methods of transformation such as decoction, infusion, and gargles are taken as a drink, bath, or massage. Knowledge about the use of these medicinal plants as brushes and their properties is passed down from generation to generation. The virtues of these plants constitute secrets for populations.

Plant brush species are used by the populations of the Kpakpamè District to treat various conditions ( Figure 3 ).

It appears from the analysis of Figure 3 that tooth decay (33.33%) is the disease most commonly treated by plant species used as brushes among populations. Next come malaria (11.90%), bad breath (9.52%), and teething problems (9.52%). On the other hand, constipation and diabetes with a proportion of 2.38% each, are diseases that are sometimes treated. Thus, local populations have strong knowledge of the treatment of diseases through the use of plant brush species.

The many uses made of plant brush species make them vulnerable. The different pressures identified on the ground concern activities linked to vegetation. These include agricultural activities, medicinal exploitation, timber exploitation, and livestock breeding.

As measures of sustainability and protection of the species identified and used as a vegetable toothbrush by the population, these are reforestation (13.04%), awareness raising (19.57%), and the creation of vegetable garden. The creation of home gardens is the best-recommended measure to facilitate the domestication of species.