Retrospective Evaluation Of The Effect Of Botulinum Toxin-A Injection Applied To The Mental Muscle On Free Gingival Graft Operation: A Randomized Controlled Clinical Study

INTRODUCTION The FGG operation is a versatile surgical procedure that is frequently used in the treatment of gingival recessions to increase the width of the attached gingiva, the depth of the vestibule and to close the open root surface. While it is a more successful method in closing the open root surface in patients with Miller class I and II gingival recessions without bone loss, the same success cannot be observed in patients with Miller class III and IV gingival recessions with bone loss in the interdental area. The most important factors affecting the success of the FGG operation are the ensurement of the nourishment of the graft by maintaining the blood supply and the ensurement of graft immobility in the early recovery period by blocking the return of the dissected muscle attachments to their original position. Insufficient blood supply to the recipient bed where the graft is placed causes necrosis in the graft. In this case, there is a risk that the root surface cannot be completely covered. In addition, due to the desire of the dissected muscle attachments to return to their original position, there is a risk of not being able to achieve the desired amount of keratinized band increase.

Botox (BTX) is a toxin obtained from the Clostridium Botulinum bacteria and is a microbial protein that shows its effect by blocking neuromuscular activity. Immunologically, there are 8 different serotypes of BTX (A, B, C1, C2, D, E, F, G). Serotype A is the most potent serotype and the first form used in medicine. BTX-A is an agent used in medicine and dentistry for therapeutic purposes as well as cosmetic purposes. In the field of dentistry, it is preferred as a treatment method in many pathological conditions such as oromandibular dystonia, bruxism, asymmetry due to facial paralysis, temporomandibular joint (TMJ) disorders, gummy smile, and orange peel-looking jaw. There are studies showing that BTX application causes vasodilation in the blood vessels of the injected area; increasing the amount of blood flow and oxygen delivery at the vascular, tissue, cell and molecular levels in the region. It has been reported that this effect eliminates the risk of the necrosis of the graft whose blood connection was cut due to the increased blood supply in the region and also contributes to flap viability.

The mental muscle is a pair of muscles on the right and left, starting from the jawbone at the apical level of the incisors, moving downwards, and ending at the skin. The contraction of the mental muscle, which provides the vertical support of the lower lip; raises the lower lip and chin, creating a sullen and sad expression on the face. Due to the mental muscle ending at the skin, excessive activity of the muscle causes an indented appearance of the chin, which is called the orange peel. BTX injection applied to the mental muscle contributes to the improvement of the orange peel appearance by reducing the excessive activity of the muscle.

The aim of this retrospective study was to evaluate the effects of BTX-A injection to the mental muscle on patients with Miller class III gingival recession in their lower 1st incisors who underwent the FGG operation due to insufficient keratinized gingiva, on the basis of clinical periodontal parameters. Due to the fact that BTX-A injection applied to the mental muscle increases the blood supply of the region and decreases mental muscle activity suggests that it will positively affect the clinical periodontal parameters.

MATERIAL AND METHODS This study, which was approved by the Ethics Committee of Fırat University Medical Faculty Clinical Research Ethics Committee with the number 12/27 on 01.08.2019, was supported by the Fırat University Scientific Research Projects Management Unit with the project number DHF.19.10.