Clinical Evaluation of the Use of Surgical Tube Technique Versus Hyaluronic AcidInjection in Reconstruction of the Interproximal Papilla

The interdental papilla is the gingival portion that fills the proximal area under the contact between two adjacent teeth, where it is defined as gingival tissues extending from incisal tip of the papilla to a line tangential to the adjacent margins of the adjacent teeth. Anatomically, it is small and delicate with a diminutive blood supply, it is almost the most important esthetic part during smiling.

Nordland \& Tarnow 1998 classified papillary loss according to system which utilizes 3 identifiable anatomical landmarks: the interdental contact point, the facial apical extent of the cemento-enamel junction (CEJ) and the interproximal coronal extent of the CEJ. Normal Interdental papilla fills embrasure space to the apical extent of the interdental contact point/area. Class I which the tip of the interdental papilla lies between the interdental contact point and the most coronal extent of the interproximal CEJ (space present but interproximal CEJ is not visible). Class II which the tip of the interdental papilla lies at or apical to the interproximal CEJ but coronal to the apical extent of the facial CEJ (interproximal CEJ visible). Class III which the tip of the interdental papilla lies level with or apical to the facial CEJ.

The absence of interdental papilla contributes to chronic retention of food debris leading to subsequent affection of periodontal health and esthetically unaccepted black triangle. To be influenced by the initial position of the teeth (diastema), the length of gingival niche area, triangular shaped crown, divergent roots and periodontal bone loss. Also tooth brush trauma and decreased keratinization due to ageing has also been implicated as a causative factor of interdental papilla loss.

Reconstruction of papillary insufficiency is one of the most difficult and challenging periodontal treatments. This is because the interdental papilla is a small, fragile area with minor blood supply which seems to be the major limiting factor in all surgical and augmentation techniques.

The injection of biocompatible hyaluronic acid gel (HA) have been considered conventional non-invasive techniques for treatment of deficient papilla. Hyaluronic acid (0.1) mm It is an essential glycosaminoglycan of the extracellular matrix of the periodontal tissues, and the majority of cells can produce it during several phases of their cell cycle. It is involved in tissue repair and wound healing by stimulating cell proliferation, migration and interaction with several growth factors. Furthermore, HA has a crucial role in space-filling owing to its hygroscopic nature. Moreover, it regulates osmotic pressure and enhances tissue lubrication and resiliency, which helps in maintaining the structural and homeostatic integrity of tissues.

However, hyaluronic acid gel injection still entails unpredicted complete gingival papilla improvement owing to the relative compact nature of the gingiva and influence of the gingival biotype that could hinder the positive outcomes on favor of thick biotype that could help to enrich the effect of hyaluronic acid through accelerating the thick connective tissue related abundance of gingival fibroblast proliferation, promoting the generation of collagen fibers. Limited studies have utilized HA gels for papillary reconstruction but still lacking a high degree of evidence and predictability.

Several conventional surgical approaches using traditional periodontal plastic and augmentation procedures aiming for complete papilla fill to overcome this problem. However, flap design were found to be invasive with increased patient morbidity, limited success, long-term stability and unpredictability due to small working spaces and limited blood supply.

Most of the surgical approaches targeting papilla reconstruction were based on Sub-epithelial connective tissue graft. Han \& Takei 1996 used semilunar coronally repositioned papilla based on the use of free connective tissue graft. He concluded that subsequent second- and possibly third-stage surgery should reconstruct more of the papilla which is considered one of the disadvantages of this flap design. So Pellegrine 1996 modified this technique by folding the CTG to provide adequate thickness of the attached gingiva.

Modified Beagle's technique and Beagle's surgical technique were unpredictable due to small working spaces and limited blood supply to the area in addition to the vertical releasing incisions that could further jeopardize vascular supply and leave unpleasant scarring after healing.

Han and Tackei technique made a trial to modify the flap design by semilunar coronally repositioned papilla that enabled to preserve the interdental papilla blood supply and improving the gingival biotype from 0.75 mm to 2 mm, One year post-operative view showing 80% papillary fill.

These subepithelial conventional techniques were unpredictable due to small working spaces and limited blood supply to the area. Disadvantages of these techniques were mostly due to the number and location of incisions, which could have disrupted the blood supply needed for complete healing.

Microsurgical techniques had been introduced and enhance the visual accuracy by means of illumination and magnification. Literature on periodontal microsurgery showed improved surgical outcome when used for root coverage procedure and regenerative therapy. By the aid of subepithelial connective tissue, the microsurgical technique found to maintain the reconstructed papilla remained stable and without any clinical signs of inflammation for 4 years after surgical procedure, but the long-term survivability and the technique sensitivity involved in the surgery are to be considered.

Recent clinical study assessed the efficacy of microsurgical reconstruction of lost interdental papillam and was based on single surgical intervention, with the aid of connective tissue graft which is proved useful in Correction of papillary loss, but the Maximum gain with single procedure was found to be limited. Other limitations of the study were being due to smaller sample size and short period of follow up and were recorded for long term clinical and histological follow up studies are necessary before its predictability.

Tube technique is recently introduced by Hooshang etal. 2020 on the track of surgical techniques to overcome disadvantages of the other techniques. The innovated flap design of tube technique does not disturb the blood supply of the graft by its use of apical incisions and containment of the graft within a rich vascular enclosed bed, thereby offering reliable and satisfactory results. Integrity of the soft tissue is key to the successful outcome of this technique. The tube grafting technique requires technical precision. It is sensitive to any surgical trauma and tension, especially when the recipient site tissue is delicate.

Thus, the present randomized clinical trial is to compare the clinical effect of surgical Tube technique versus Hyaluronic Acid Gel injection in Reconstruction of the interproximal papilla in patients with class II papillary defect.