Application of an active oxygen (blue®m) with free connective graft technique for root coverage – a case report

Gingival recession occurs due to the migration of the gingiva in the apical direction, leading to compromising local aesthetics and root hypersensitivity. Connective tissue graft is the gold standard treatment in these cases improving both functional and aesthetics aspects.The purpose of this case is to report root coverage using the free connective tissue graftingtechnique (CTG) associated with topical application of active oxygen oral gel and mouthwash (blue®m). A 27-year-old female sought care with the main complaint of root hypersensitivity and the presence of gingival recession in the anterior region of the mandible. Clinical examination revealed the presence of type 1 gingival recession in the left mandibular central incisor. The treatment of choice was a modified graft (free connective graft). The graft and recipient bed received applications of blue®m oral gel. The patient was instructed to use blue®m mouthwash and blue®m oral gel after the surgery for 10 days. At 60 days, the patient showed satisfactory healing in the area of the free CTG, with gain of keratinized tissue and partial covering of the gingival recession. Free CTG with the support of the gel and the mouthwash with active oxygen release makes the technique viable, preventing graft necrosis and achieving root coverage and keratinized tissue.


Introduction
Gingival recession is defined as the exposure of the root of the dental element in the oral environment, due to the migration of the gingiva in the apical direction. [1] When this occurs, some pathologies can settle in the patient, ranging from the risk of caries, erosion, root hypersensitivity and lack of esthetics (Zucchelli & Sanctis 2000;Zucchelli et al., 2011;Fernandes et al., 2021). The etiological factors of gingival recessions include inadequate restorations, poorly positioned teeth, cavities, periodontal disease and due to the inadequate insertion of the labial frenulum. It is more likely to occur in patients with a thin tissue phenotype . (Yadav et al., 2018;Storrer et al., 2019).
The new classification of gingival recessions based on the measurement of interdental clinical insertion is divided into: Type 1 recession (RT1), which has gingival recession without loss of interproximal insertion, Type 2 recession (RT2) in which there is gingival recession but with loss of interproximal insertion, in which the measure of the cemento-enamel junction is less than or equal to the loss of buccal insertion, Recession type 3 (RT3) in which there is gingival recession but with loss of interproximal insertion, in which the measure of the cemento-enamel junction is greater than the loss of oral insertion (Cortellini & Bissada 2020).
The free gingival graft technique (FGG) has great predictability of success in treating gingival recessions, having also been widely used to gain keratinized tissue. However, it has some disadvantages, such as the discrepancy in texture and colormismatch between the healed graft and the graft recipient area (Zucchelli et al., 2006;Zucchelli & Mounssif 2015;Yoshino et al., 2020;Araujo et al., 2021). The use of subepithelial connective tissue graft (CTG) is reported to be the gold standard for correcting these defects, including as its greatest advantage the increase in the volume of soft tissue and the contouring of the gingival margin (Sculean et al., 2014;Thoma et al., 2020).

Methodology
This article is a case report, approached in a descriptive and qualitative way, where considering that oxygenation is a major determinant of healing outcomes, and in order to minimize the main disadvantage of the free CTG, the purpose of this case is to report a root coverage using the free CTG associated with topical application of the gel and mouthwash blue®m to aid healing. The informed consent form was signed by the patient. The treatment of choice was a free connective tissue graft to avoid the whitish aspect of a free gingival graft.

Case Report
After measuring blood pressure, which presented normal range (120/80mmHg),intra and extra-oral antisepsis was performed followed by infiltrative anesthesia in the antero-inferior region with articaine 4% plus epinephrine 1: 100,000, (Articaine DFL, Rio de Janeiro -RJ, Brazil). In the same surgical procedure, prior to the graft, the lower lip frenectomy was performed. With the aid of two curved hemostatic forceps, the lower lip frenulum was pinched (Figure 2 B) and with a 15c scalpel blade (Solidor, China, People's Republic), it was removed. The gingival region inserted laterally to tooth was deepithelialized, preparing the recipient bed to receive the graft (Figure 2 C).
Using the sterile suture paper, a surgical map was made to plan the necessary graft size ( Figure 2D). The map was taken to the donor bed (palate) in the region between the distal of the canine and mesial of the first molar ( Figure 2E), to demarcate the region of graft removal ( Figure 2F). With a 15c scalpel blade (Solidor, China, People's Republic), the incision was made, and the graft was removed as in the FGG technique ( Figure 2G). After its removal, it was left on sterile gauze moistened with saline solution and the donor bed was sutured with continuous scalloped suture ( Figure 2H).
. Amoxicillin 500mg was prescribed, one capsule every eight hours for seven days, ibuprofen 600mg, one tablet every eight hours for three days, paracetamol 750mg, one tablet every eight hours for three days. The patient was orientated to use blue®m mouthwash every eight hours for 10 daysas well as to use the blue®m oral gel once a day until the sutures were removed.
The patient reported little postoperative pain. The sutures were removed 10 days after the operation, and it was possible to see that the free connective graft and the donor area of the graft showed satisfactory healing ( Figure 3F and 3G). After 40 days of post-operative, the healing tissue was clinically observed and a decrease in the whitish area of the graft was noted suggesting better irrigation in the region ( Figure 3H). At 47 days, the lower lip frenulum had a small recurrence (Figure 4A), so a new intervention ( Figure 4B) was necessary, as previously described in the first surgery, and simple sutures were performed ( Figure 4C).
At 60 days, the patient showed excellent healing in the area of the free CTG, with gain of keratinized tissue and partial covering of the gingival recession ( Figure 4D). The patient was followed up for 60 days and the results achieved were maintained, as well as the patient's total satisfaction regarding aesthetics and elimination of root hypersensitivity. At 280 days postoperatively, the patient returned for follow-up, and a considerable gain in keratinized tissue and almost the absence of color discrepancy between the graft's receiving area and the keratinized mucosa could be noted ( Figure   5).
The free gingival graft is one of the oldest techniques of gingival grafting, and its efficiency is proven in the long term, but the success of this graft depends on the transplanted connective tissue, its integration takes around 17 days showing a fibrous tissue that can differentiated from the receiving area (Cairo, 2017;Lafzi et al., 2019), which is the main disadvantage of FGG in aesthetic areas. Due to this limitation, we opted to perform the free CTG. Looking at the post-operative follow-up photos of the present case, it is possible to observe that the whitish staining in the recipient bed was minimized but not eliminated. This is also a limitation of the free connective graft in this case report.
Subepithelial connective tissue grafts are considered one of the best methods for root coverage and also to increase the width and thickness of keratinized gums (Han et al., 2008;Henriques et al., 2010;Yadav et al., 2018) with good predictability due to the blood supply coming from both the periosteum and the flap that covers the graft, thus preventing its necrosis (Yadav et al., 2018). However, in the technique used in this clinical case, connective tissue was used as a technique for free gingival graft, anchored in the recipient bed, which is the only source of blood supply for the graft.
Oxygen plays an important role in wound healing. It is required, among others, for collagen deposition, epithelization, and angiogenesis, besides providing resistance to infections (Lafzi et al., 2019). It has been demonstrated that topical application of a product that releases oxygen (blue®m) reduces the severity of inflammation in vivo (Eisenbud, 2012;Imano et al., 2019). To aid healing and increase local angiogenesis, it was decided to daily apply the blue®m oral gel in the immediate postoperative period and until the sutures were removed, as well as to indicate the use of the blue®m mouthwash in order to minimize risk of necrosis of the free conjunctive graft. The free gingival graft has its epithelium coming from the palate which favors its predictability and decreases the chance of necrosis; however, it has a disadvantage, the discrepancy in color and texture in contrast to the recipient bed (Yoshino et al., 2020).
As for the histological aspect, connective tissue cells are derived from mesenchymal cells, being pluripotent stem cells, however this connective tissue is an adult tissue that contains a small amount of these mesenchymal stem cells, being able to be transformed into fibroblasts, and myoblasts that contribute to tissue repair, in addition to the production of growth factors and cytokines, which influence the differentiation of other cells such as muscle and epithelial cells. When this technique is performed, the tissue tends to have a color and texture like keratinized mucosa due to the influence of the cells of the recipient site. Thus, the need to remove this epithelium, cells that had different coloring and texture from the donor site (palate) are removed, making the FCG become more aesthetic than the FGG (Montanari, 2016;Yoshino et al., 2020).
The FGG de-epithelialization technique, with the removal of the epithelial portion, is already established in the literature (Mattos et al., 2019) and was used in this case to perform the FCG. However, there is a chance of necrosis due to the removal of the epithelium, so we decided to apply products that have the release of active oxygen in their formulas. It is known that the presence of oxygen in wound healing is essential because it promotes increased cellular metabolism, increased collagen synthesis, increased antibacterial activity, promotes, and facilitates the release of growth factors, increases angiogenesis, and promotes revascularization (Eisenbud, 2012). Besides, its antimicrobial effects have also been demonstrated (Imano et al., 2019).
As the active oxygen-releasing gel (blue®m) developed by dental surgeons from the Netherlands, helps in the healing and formation of keratinized tissue (Imano et al., 2019).in the present case, in the technique of free connective tissue grafting, satisfactory healing was observed probably due to the angiogenic stimulus and the antibacterial effect of the blue®m products used. The clinical result shows absence of necrosis in the initial 10-day postoperative period. We suggest that the use of products with active oxygen release this technique became a viable procedure, since other attempts had already been made by the same team and we were unsuccessful due to necrosis of the free conjunctive graft. In addition, a tissue of color and texture similar to the recipient bed was observed in the postoperative follow-up (Montanari, 2016;Imano et al., 2019).

Conclusion
It is concluded that the technique of free connective graft performed, with the support of the gel and the mouthwash with the release of active oxygen (blue®m), has become a viable technique, preventing graft necrosis and achieving root coverage and keratinized tissue gain. New clinical trials and must be carried out to observe the effects of oxygen therapy on the technique of free connective tissue grafting