An insertion material intended for widening the gingival crevice, characterized in that it consists of a hydrophilic paste comprising, expressed as percentage by weight relative to the total weight of the material: - between 5 and 15% of an astringent; - between 25 and 50% of a texturizing agent chosen from: - hydrophilic biopolymers; - hydrophilic biopolymers combined with plant fibers; - hydrophilic biopolymers combined with plant fibers and with polyvinyl alcohol; - plant fibers combined with polyvinyl alcohol; - between 30 and 60% of water; and - between 0 and 20% of a humectant; - the total amount of water and humectant being between 35 and 65% by weight relative to the total weight of the material; - the abovementioned hydrophilic biopolymers being chosen from the group consisting of pectins; galactomannans of guar, locust bean or tara seeds; scleroglucan; xanthan and carrageenans, preferably of iota type, and mixtures thereof; - the abovementioned plant fibers being chosen from pea fibers and oat fibers; - the astringent being chosen from the group consisting of iron or aluminum chlorides and sulfates, potassium aluminum sulfate, and mixtures thereof; - said insertion material having the following release profile for the astringent, measured according to the dissolution method described in the European Pharmacopoeia, 6th edition (Ph. Eur. 2.9.3 (01/2008)) at 150 rpm in 700 ml of purified water at 37°C: - less than 20% of astringent released after 5 min; - less than 40% of astringent released after 10 min; - less than 50% of astringent released after 15 min; - less than 60% of astringent released after 30 min; - less than 80% of astringent released after 60 min. - between 5 and 15% of an astringent; - between 25 and 50% of a texturizing agent chosen from: - hydrophilic biopolymers; - hydrophilic biopolymers combined with plant fibers; - hydrophilic biopolymers combined with plant fibers and with polyvinyl alcohol; - plant fibers combined with polyvinyl alcohol; - hydrophilic biopolymers; - hydrophilic biopolymers combined with plant fibers; - hydrophilic biopolymers combined with plant fibers and with polyvinyl alcohol; - plant fibers combined with polyvinyl alcohol; - between 30 and 60% of water; and - between 0 and 20% of a humectant; - the total amount of water and humectant being between 35 and 65% by weight relative to the total weight of the material; - the abovementioned hydrophilic biopolymers being chosen from the group consisting of pectins; galactomannans of guar, locust bean or tara seeds; scleroglucan; xanthan and carrageenans, preferably of iota type, and mixtures thereof; - the abovementioned plant fibers being chosen from pea fibers and oat fibers; - the astringent being chosen from the group consisting of iron or aluminum chlorides and sulfates, potassium aluminum sulfate, and mixtures thereof; - said insertion material having the following release profile for the astringent, measured according to the dissolution method described in the European Pharmacopoeia, 6th edition (Ph. Eur. 2.9.3 (01/2008)) at 150 rpm in 700 ml of purified water at 37°C: - less than 20% of astringent released after 5 min; - less than 40% of astringent released after 10 min; - less than 50% of astringent released after 15 min; - less than 60% of astringent released after 30 min; - less than 80% of astringent released after 60 min. - the total amount of water and humectant being between 35 and 65% by weight relative to the total weight of the material; - the abovementioned hydrophilic biopolymers being chosen from the group consisting of pectins; galactomannans of guar, locust bean or tara seeds; scleroglucan; xanthan and carrageenans, preferably of iota type, and mixtures thereof; - the abovementioned plant fibers being chosen from pea fibers and oat fibers; - the astringent being chosen from the group consisting of iron or aluminum chlorides and sulfates, potassium aluminum sulfate, and mixtures thereof; - said insertion material having the following release profile for the astringent, measured according to the dissolution method described in the European Pharmacopoeia, 6th edition (Ph. Eur. 2.9.3 (01/2008)) at 150 rpm in 700 ml of purified water at 37°C: - less than 20% of astringent released after 5 min; - less than 40% of astringent released after 10 min; - less than 50% of astringent released after 15 min; - less than 60% of astringent released after 30 min; - less than 80% of astringent released after 60 min. - less than 20% of astringent released after 5 min; - less than 40% of astringent released after 10 min; - less than 50% of astringent released after 15 min; - less than 60% of astringent released after 30 min; - less than 80% of astringent released after 60 min.