Contouring the Emergence Profile of Peri-implant Soft Tissue by Provisionals on Implants – Case Report

Summary Aesthetic outcome of implant therapy involves the appropriate architecture of peri-implant soft tissue and interdental papilla. The dynamic compression technique of soft tissue is mentioned in contemporary literature as one of the methods for achieving optimal emergence profile. The aim of this case report was to present soft tissue prosthetic modeling with temporary crowns on implants for obtaining an emergence profile of final restoration. A 25-year-old female patient with missing left maxillary central incisor was referred to the Department of Oral Surgery School of Dental Medicine University in Belgrade for dental implant placement. After detailed planning, implant placement of Straumann Bone level implant NC Ø 3, 3×12 mm (Straumann® Bone Level NC), in the position of 21 was performed. Upon completion of osseointegration period, screw retained laboratory temporary crown was fabricated. During the next 3 months emergence profile was scalloped by creating additional pressure on the soft tissue with periodic adding the composite resin material to a temporary crown. The created emergence profile was transferred to the master cast by using customized impression coping, making possible fabrication of the final implant restoration according to the design made with provisional restoration. Soft tissue conditioning using temporary dental restorations on implants presents a non-invasive method with predictable aesthetic result.


INTRODUCTION
Traditionally, one of the main objectives of an implant treatment has been to ensure osseointegration [1][2][3][4]. On the other hand, the achievement of implant osseointegration does not always correlate with successful esthetic outcome [5]. In the early period of implant dentistry, implants were placed with a "Bone driven implant placement concept". According to this concept, an implant is placed at the crest of the bone, which has a sufficient amount of the bone, however, this is not always an ideal implant position for the final restoration. Therefore, this could result in an unaesthetic and nonfunctional implant restoration. Recently, with the development of several bone grafting materials, guided bone regeneration (GBR) techniques, and improvement of technology of implant surface treatment, the concept of implant treatment has been changed to "Prosthetically driven implantation" [6]. Consequently, there is now an increased demand for aesthetic restorations with healthy peri-implant soft tissue.
The emergence profile is one of the key factors in the establishment of the optimum hard and soft tissues. In particular, in the esthetic zone, the emergence profile of dental implant restorations should mimic natural teeth [7,8]. Improperly contoured restorations will cause compromised access for oral hygiene and inflamed soft tissue that can induce unaesthetic results [9]. Accordingly, properly contoured restoration with a natural emergence profile and gingival architecture that harmonizes with adjacent teeth is very important for aesthetic and functional im-plant therapy [10]. To achieve an optimal emergence profile, several factors need to be considered from the initial to the final stages of the treatment. In the presence of an appropriate tissue base, achieving an optimal emergence profile depends on the selection of implant, healing abutment, and intermediate prosthetic element selection.
The term "emergence profile" was first used in 1977 by Stein and Kuwata [11] to describe tooth and crown contours as they traversed soft tissue and rise toward the contact area interproximally and height of contour buccally and lingually. In 1990, a photographic analysis of natural teeth by Croll [12] confirmed that most emergence profiles are relatively straight as opposed to convex or concave. If a restoration introduced a convexity or concavity where it didn't belong, the unnatural contour might trap plaque or otherwise disrupt gingiva. Since the introduction of dental implants, there has been renewed interest in this concept as dentists attempt to replicate not only the crown but also the entire tooth anatomy. Unnatural emergence contours may trap plaque and be difficult to maintain hygienically. Additionally, human eye may detect a final restoration in the esthetic zone that has not faithfully reproduced what nature originally provided.
Neale and Chee [7] in 1994 were perhaps the first to describe a technique for surgically sculpting soft tissue around an implant to more closely mimic nature. More recent published technique describes modifying provisional crowns incrementally rather than a surgical approach [13].
The aim of this paper was to present gingival recontouring by fabricating and adjusting provisional implant restoration to produce an optimal emergence profile for the final implant restoration.

CASE REPORT
A 25-year-old female patient with missing left maxillary central incisor without periodontal/implant risk factors was referred to the department of Oral Surgery School of Dental Medicine University in Belgrade for dental implant placement. According to the protocol of prosthetically driven implantation, implant placement of Straumann Bone level implant NC Ø 3, 3×12 mm (Straumann® Bone Level NC), in the position of 21 was performed.
After period of oseointegration implant was "opened'' and healing abutment was placed ( Figure 1). After 15 days, emergence profile was too narrow and customizable healing abutment was positioned (Figures 2 and 3). One month later open tray impression with addition silicone was performed. Laboratory-processed, screw-retained provisional restoration was made on the temporary abutment. The provisional was made from light-and heatcuring microfilled composite (Adoro SR, Ivoclar Vivadent AG). The material was contoured and highly polished to       6). After completion of soft-tissue conditioning and maturing phase, created emergence profile was transferred to the master cast by using customized impression coping ( Figure 7). The identical soft-tissue profile in the master cast was established intra-orally, making possible the fabrication of the final implant restoration according to the design made with the provisional restoration (Figures 8 and 9).

DISCUSSION
Aesthetic result of implant restorations depends on prosthetically and biologically driven implant placement [14], visually satisfying restoration [15,16] and architecture of the surrounding peri-implant soft tissue [17]. The evolution of concept of the surgical implant therapy has led to improved osseointegration, but even after the successful surgical approach, prosthetic management of soft tissue in the esthetic zone is a challenge.
Techniques that present soft tissue shaping with provisional restorations on implants can not be found in the literature, and only a few case studies on this topic have been published. So far the only presented technique of peri-implant soft tissue modeling is by adding composite resin to a provisional during the period of the soft tissue conditioning [18,19]. In the initial phase, it is important to squeeze the tissue into the right direction. This is especially important in the papillary region where tissue will not have enough space to mature and fill in the space for papilla due to slightly overcontoured temporary crown after addition of composite material. So the dynamic compression method uses the pressure in the initial stage as round shaped emergence profile is achieved with transmucosal healing cap. Pressure is increased in several steps in order to avoid necrosis, anemia or pain. Pressure with the provisional restoration pushes soft tissue laterally in order to direct it in the right way, but it is also important that temporary restoration is undercontoured, particularly in the area of papilla, so that the tissue could be designed to fill in the created space. The presented modification of temporary crown technique is of crucial importance to finalize the architecture of soft tissue and improve the aesthetic result. Conditioning the soft tissue with provisional restoration represents, compared to the surgical technique, less invasive method with predictable aesthetic outcome. Its primary disadvantage is that it takes a longer time. To confirm the validity of this new technique clinical studies are necessary to examine the long-term stability of peri-implant soft tissue as well as in vivo histological analysis that would show precise structure of formed tissue.
Dynamic compression technique in the esthetic zone is a clinical method based on the initial pressure and subsequent modification of provisional restoration by creating space in the papillary region. Our clinical outcome, with a limit of one case report, showed that temporary crown can be used to form the emergence profile of peri-implant soft tissue in harmony with the adjacent teeth, as well as to achieve proper height and width of interdental papilla. Temporary crown also facilitates communication between the patient, dentist and dental technician and provides predictable and extraordinary aesthetic result with final restoration.