The oral mucosa, and the gingival margin in particular, represents a delicate interface, where the thinness of the epithelium is combined with substantial vascularization and a surface in direct contact with the bacterial biofilm. Traditional oral hygiene formulations, however effective they may be in terms of cleansing or antiseptic action, often fail to address the underlying problem of prolonged protection for soft tissues, limiting themselves to a transient action that fades away within a few minutes of rinsing. It is precisely in this applicative space that sericin is beginning to find a precise place for itself.
How sericin interacts with soft tissues
Sericin's ability to form thin films stems from its molecular structure, characterized by a high proportion of serine, threonine, and aspartic acid residues, which give it a pronounced hydrophilicity and the capacity to establish hydrogen bonds with mucosal surfaces. When a sericin-containing solution comes into contact with the oral epithelium, the protein tends to adhere to the tissue surface through these polar interactions, spreading out into a thin, relatively uniform layer that, once dried or stabilized, takes on a configuration reminiscent, in certain respects, of a semipermeable film.
This film should not be understood as a rigid, occlusive barrier, but rather as a dynamic layer that modulates the exchanges between the oral environment and the underlying mucosal surface. On one hand, it reduces the direct exposure of tissues to irritants present in saliva or food; on the other, it limits superficial dehydration of the epithelium, a factor that is often underestimated but clinically relevant in conditions such as xerostomia, or following treatments that alter salivary production, for example radiation therapy for head and neck cancers or certain chronic pharmacological therapies.
An interesting aspect, which has emerged from several studies on sericin applied to biological substrates, concerns its ability to modulate microbial adhesion to the surface on which it is deposited. The protein film appears to interfere with the early stages of bacterial colonization, making it less favorable for cariogenic and periodontopathogenic microorganisms to aggregate on the tooth and gingival surface, an effect that, if confirmed on a larger scale in clinical oral settings, would open up interesting prospects for the prevention of plaque and tartar in their initial stages.
Anti-inflammatory and healing properties
While the film-forming action represents the primary physical mechanism, it is on the biological side that sericin shows the most promising potential for gum health. The literature on biomaterials derived from the silkworm has increasingly documented sericin's ability to modulate the inflammatory response at the tissue level, acting on some of the molecular pathways involved in the production of pro-inflammatory cytokines. This effect, first observed in models of skin wound healing and subsequently extended to contexts of soft tissue regeneration, finds a natural field of application in gingivitis and in the early stages of periodontal disease, conditions in which low-grade chronic inflammation plays a central role in the progression of tissue damage.
Sericin also possesses a well-recognized antioxidant activity, linked to its ability to neutralize free radicals and counteract oxidative stress at the cellular level. In the oral context, where the metabolic activity of the bacterial biofilm continuously generates reactive oxygen species, this property takes on a practical significance that should not be overlooked: a gingival environment less exposed to oxidative stress tends to maintain the integrity of the epithelial barrier for longer, along with a less dysregulated local immune response.
Finally, sericin's contribution to tissue repair processes deserves attention as well. Several studies conducted on skin wound models have shown that the protein promotes fibroblast proliferation and the reorganization of the extracellular matrix, accelerating wound closure times. Transferred to the gingival context, this effect could translate into useful support during the recovery phases following periodontal treatment, after scaling and root planing procedures, or in the presence of gingival microlesions caused by aggressive brushing, a condition that is far from rare in the general population.
From mouthwashes to topical gels
Sericin's physicochemical characteristics make it compatible with various pharmaceutical and cosmetic forms intended for oral hygiene. In mouthwashes, the protein can be incorporated into an aqueous solution at relatively low concentrations, taking advantage of its solubility and its ability to deposit onto the mucosa during rinsing, leaving behind a protective film that persists even after the liquid component of the product has been eliminated. This type of formulation lends itself particularly well to complementary use alongside chlorhexidine-based or essential oil-based mouthwashes, and could be proposed as a subsequent step to prolong the soothing action without interfering with the antiseptic effect of the primary treatment.
In toothpastes, incorporating sericin requires more careful formulation work, given the need to balance the protein component with the abrasive agents and surfactants typically present in these matrices, which could otherwise compromise its stability or film-forming activity. The most recent formulations tend to favor low-abrasion systems and gentle surfactants, in order to preserve the integrity of sericin and allow it to fully express its protective function on the gingival margin during brushing.
Medical devices intended for the treatment of gingivitis and mucositis, including those induced by chemotherapy or radiotherapy, also represent fertile ground for the use of sericin, thanks to the combination of physical barrier action and biological support for tissue repair, two needs that in these patients arise simultaneously and with particular clinical urgency.
