Multidisciplinary approach in treatment of spacing: orthodontic treatment and partial ve-neers using the injectable composite resin technique

the to composite restorations. injectable composite the gentle on lateral incisors and canines, using the injectable composite resin technique as a simple and predictable solution for minor restorative interventions to solve morphological tooth abnormalities in the esthetic smile zone.


INTRODUCTION
Anterior spacing and tooth size discrepancy is one of the most common features in adult dentition. Meeting patient's demands and expectations is the first step in deciding which treatment option is the best for optimal esthetic results. Orthodontics alone can give a great esthetic improvement, but multidisciplinary treatment is often needed for excellent treatment outcomes. Most often, orthodontic treatment is followed by restorative treatment [1,2]. Direct restorations are done in one session, applying layers of composite directly to the tooth surface. Indirect restorations are preferred in complex cases, and they require collaboration with dental technicians [3]. Direct restorations are practical and have several advantages, such as saving the tooth structure; reversibility of procedure, lower cost to the patient, and the material can be added or removed easily, if necessary [1,4,5].
The injectable resin composite technique is a predictable dental procedure where a diagnostic wax-up is translated into composite restorations. It is an indirect/ direct technique that can be used to repair fractured teeth and restorations, provisional restorations, veneers, resurfacing occlusal wear on posterior composite restorations, and also in primary dentition for teeth with multiple caries or fractures [6,7]. This technique is minimally invasive and relatively inexpensive compared to conventional ceramic veneers procedure, and tooth preparation is mostly not required [8].
The aim of this case report is to present management of spacing in the anterior region by orthodontic treatment followed by partial veneers using the injectable composite resin technique.

CASE REPORT
A 32 years old male patient presented to the dental office complaining about his smile's esthetic appearance. He did not like the misalignment of the anterior teeth as well as the spaces between them.
The main cause of spacing in his case was a discrepancy of tooth size and arch length. In his case, the labial frenulum was not prominent. In occlusion, molar and canine relation was class I on both sides. Cephalometric analysis did not show skeletal discrepancies, and both upper and lower incisors were proclined. Orthodontic treatment aimed to level and align dental arches, correct the upper and lower incisors' position, close the diastemas in the upper and lower dental arch, and achieve good occlusion. Since esthetics was very important for the patient even during the orthodontic treatment, ceramic braces (Radiance, American orthodontics, Roth prescription, slot 22) were chosen. Standard arch wire protocols were followed and power chains were used for closing the spaces between the teeth. (Figures 1, 2).
After 13 months of orthodontic treatment, all diastemas were closed and a stable static and functional occlusion achieved. Although all the spaces were closed in gingival areas of teeth, black spaces between upper lateral incisors and canines were visible in incisal parts. Recontouring of lateral incisors and canines was necessary to enhance the esthetic outcome ( Figure 3). Direct composite buildups could be a solution in minimally invasive and non invasive cases, since they are esthetic, functional, and biologically sound treatment options for closing diastemas with clinically promising survival rates [1]. After explaining possible treatment options, the patient decided to take a restorative treatment based on the injectable resin composite technique because it offers esthetic and predictable results and no dental tissues preparation. For this technique, an adequate design of the restoration is needed. Intraoral and extraoral photos of the patient were taken with a digital camera (D3400, Nikon corporation) and esthetic parameters evaluated. The future shape of lateral incisors and canines were designed in Keynote software (Apple Corporation). According to this design, partial veneers wax-up was made ( Figure 4) Two veneers were planned on distal incisal surfaces of upper lateral incisors and two on mesial surfaces of canines to enhance the smile esthetics.
Based on the wax-up, a transparent silicone index was made using a clear polyvinyl siloxane ( Exaclear,GC Corp.,Tokyo, Japan). Before making the silicone index, in order to hydrate, the plaster model was soaked in the cold water and left in for 5 minutes. Impression tray was     . Preparation of impression tray using silicone stops to save the same thickness of the material Slika 5. Priprema kašike za otisnu masu uz pomoć silikonskih stopera koji obezbeđuju istu debljinu materijala prepared using stoppers made of C -silicone (Zeta plus putty, Zhermack) to save the same silicone thickness in every part of the silicone key ( Figure 5). Small perforations through the silicone index were made using the syringe of flowable resin composite ( Figure 6). The perforations were made to the distal parts on the incisal edges of lateral incisors and canines' mesial parts. The material chosen for this intervention was a highly filled flowable resin composite (G-aenial Universal Injectable, GC corporation). The teeth were cleaned using fluoride-free polishing paste. Choosing the right color was done at the very beginning of the procedure, using a small amount of the material (composite buds) on the lateral incisors and canines, which were then light-cured. Shade A2 was selected for the procedure (Figure 7). The adjacent teeth were isolated using Teflon tape. One lateral incisor's polished enamel surface was etched with 37% phosphoric acid (37.5% Phosphoric Acid Gel, Kerr) for 40s, rinsed with water and air-dried. The universal adhesive (GC G-Premio Bond, GC Corporation) was applied to pre-etched surfaces with a micro brush for 10 sec, then air blown for 5 sec, and polymerized using a LED light-curing unit (3M Elipar™ DeepCure-S LED Curing Light) for 10 sec, according to manufacturers' instructions ( Figure 8). The silicone index was positioned carefully and flowable resin composite injected through the perforation made on the incisal part of the silicone index for right lateral incisor (Figure 9). The restoration was light-cured for 40 sec from labial, occlusal and palatal direction. The     . Patient's smile after orthodontic and restorative procedure Slika 11. Osmeh pacijenta posle završene ortodontske i restaurativne procedure silicone index was removed, and the rest of the material was cut off with a scalpel. The procedure was repeated for right canine, and left lateral incisor and canine, one tooth at a time, protecting the finished restorations with the Teflon tape. Due to incredible precision of silicone index, the restorations required only simple and gentle polishing and finishing with finishing discs and silicone points. Proximal surfaces were smoothened with polishing strips. After polishing the restorations, new thermoplastic retainers were made to prevent tooth alignment changes after orthodontic treatment (Figures 10, 11).

DISCUSSION
Management of spacing in adults often requires a multidisciplinary approach for optimal results. Tooth alignment and stable static and functional occlusion can be achieved with orthodontic treatment, but the tooth shape abnormalities can be solved with indirect restorations (ceramic or composite) or by direct composite restorations.
Ceramics has always been a material of choice for anterior restorations because it is biocompatible, chemically stable, and effective in reproducing the tooth's natural translucency and structure. On the other hand, ceramic veneers require precise preparation since the preparation, among other causes, can be the reason for veneer fracture [3].
The injectable technique is relatively simple and gives a predictable outcome. Compared to direct composite restorations, this technique's main advantage is that it is less challenging and time-consuming. The injectable technique doesn't require preparation, which is very important in preserving sound dental tissues, especially in young patients [6][7][8][9][10]. In our case, the material used was G-aenial universal Injectable (GC Corporation), a highly filled injectable composite resin with improved mechanical properties and esthetics. The same material was used in the report of Hosaka et al. [10], whereas a group of authors in another study [9] used different, but also a highly filled flowable resin composite, G-aenial Universal Flo (GC Corporation).
The clinical effectiveness of these highly filled flowable materials was similar to paste-type composite in 36 months follow-up, in posterior restoration [11]. The study of Lai et al., who evaluated the surface gloss, roughness, and colour change of six different flowable composites, found that G-aenial universal Flo, termed as universal injectable composite by manufacturer, showed better surface properties after tooth abrasion than other composites tested [12].

CONCLUSION
Management of anterior spacing, as one of the most common dental features in adult patients, requires a comprehensive treatment for optimal esthetic and functional results. In the presented case, orthodontic treatment was followed by partial veneers on lateral incisors and canines, using the injectable composite resin technique as a simple and predictable solution for minor restorative interventions in the esthetic smile zone.