## 1 Introduction  
Traumatic dental injuries are common in children and young adolescents [1]. Permanent teeth with root fractures and luxations require careful repositioning or replantation, followed by splinting [2]. The period of splinting varies depending on the type of injury. The splint is removed after one to four weeks in most cases (avulsion, subluxation and lateral, intrusive and extrusive luxation injuries), but may be left in place for as long as 12 weeks after certain injuries, such as root fractures [2]. The Titanium Trauma Splint (TTS, Medartis AG, Basel, Switzerland) was designed for this application. The TTS is a simple appliance that meets contemporary esthetic standards [3,4]. It is bendable and can therefore be adapted to the dental arch. The matt-silver TTS consists of intersecting rhombuses with gaps for the application of composite resin materials (CRM) to bond the splint to the teeth. Tooth-colored composite makes the TTS inconspicuous but is also difficult to differentiate from tooth enamel during splint removal [5].  
Modern tooth-colored composite restorations can nearly perfectly imitate the visual appearance of the tooth structure [6]. Fluorescent materials, such as rare earth oxides, are added to the glass fillers of CRM to match the fluorescence properties of the enamel and dentine [7; 8; 9]. Nevertheless, the fluorescence emissions of these restorative materials differ from those of natural tooth structure when illuminated at different wavelengths of light [9]. The maximum fluorescence of composite resin materials occurs at a wavelength of (398 \(\pm\) 5) nm [9]. The Fluorescence-aided Identification Technique (FIT) takes advantage of the different fluorescence properties of CRM and makes CRM appear brighter than natural tooth structure when illuminated with fluorescent light [10].  
Several studies have shown that, compared to conventional illumination, fluorescence illumination improves the identification of composite fillings and selective composite removal on teeth in general and in posterior teeth [10; 11; 12; 13; 14; 15; 16; 17; 18]. FIT is a straightforward, fast, non-invasive diagnostic tool with good reliability and operator agreement [10]. Furthermore, FIT facilitates orthodontic bracket debonding [19; 20; 21] and the detection of composite restorations in forensics [13; 22; 23].  
[PERSON] et al. showed the use of FIT to be beneficial during the removal of composite bonded trauma splints [5]. Compared to conventional dental lighting, using FIT resulted in significantly fewer composite remnants and less iatrogenic defects [5].  
The potential consequences of composite remnants include esthetic impairment due to discoloration of composite margins and plaque retention spots that may result in demineralization of the enamel over time [24; 25]. Furthermore, composite remnants may impair the bond strength of later adhesive restorations, which are often required after dental trauma [26; 27; 28; 29; 30].  
The detection of composite remnants after trauma splint removal by a dentist or dental student who did not remove the splint initially has not been investigated to date. Therefore, the aim of this study was to compare the FIT versus conventional method (CONV) of detecting composite remnants after trauma splint removal in terms of the accuracy and procedure time, as well as with respect to the professional experience and gender of the examiner.