## 4 Discussion  
It is now well established that the attachments play a fundamental role in performing specific dental movements in invisible orthodontics. One of the basic requirements is to clinically report the exact position and orientation of the attachments [25; 39; 40], which has been planned virtually. However, scientific research has only described this concept in descriptive studies [21]. Currently, the clinical procedure used for reproducing attachments involves using a transfer template with planned shapes, which will be filled with composite resin. After treating the vestibular surface of the teeth with adhesive techniques, the template is placed in the dental arch for attachment-tooth adhesion. Finally, each positioned auxiliary element is polymerized [36]. The bonding process requires careful attention to minimize errors. Key factors include the choice of resin-based composite [30] and the correct use of the transfer template [26]. Unfortunately, there is currently no standard clinical protocol that includes the ideal type of composite for attachments. [PERSON] et al. [32] indicated that flowable, conservative, and orthodontic composites are all suitable, although orthodontic composites may have higher overflow. [PERSON] et al. [30] found that bulk-fill resins maintained their shape but showed surface alterations over six months, with acceptable clinical performance. [PERSON] et al. [31] suggested that bulk-fill resins are better suited to aligners than flowable resins. Recently, [PERSON] et al. [28] showed that the higher viscosity of conventional composites is more suitable for clinical procedures as they had the best wear performance. In addition, the recent study by [PERSON] et al. [41] reported that the clinician should focus more on the choice of composite resin than on the type of transfer template (rigid or soft). Figure 6: SEM observations of the resin–enamel interface in three samples from the control group. Interface areas were marked at (**a**) 720\(\times\), (**b**) 610\(\times\), and (**c**) 620\(\times\). Non-integration between enamel (E) and resin (R) with gaps, cracks, and air bubbles is visible in (**d**) 1850\(\times\), (**e**) 1800\(\times\), and (**f**) 1850\(\times\). In fact, errors with flowable composites can be due to air bubbles during bonding, whereas viscous resins prevent material loss [41]. The absence of a standardized protocol is an important issue to address because it reflects the inherent variability among practitioners in clinical practice, adapting available attachment placement procedures according to individual experience and available resources. To try to reduce operational errors during the attachment reproduction procedure, this research evaluates in vitro an innovative clinical experimental technique that is simple, effective, and predictable. Our study recognizes the variability among clinicians and aims to contribute to the development of a more standardized approach by rigorously testing and documenting the results of this technique under controlled conditions. The first template is exposed to etching only the tooth surface involved by the holes with the same attachment shape. Selective enamel etching could also result in more precise adhesion of the adhesive resin and composite. Subsequently, the pre-loaded template is immediately placed in the dental model, and polymerization is performed for each attachment. Comparisons between the proposed technique and the commonly used procedure reported interesting results. First, the experimental group had a lower incidence of morphological defects in attachments than the control group (11.5% vs. 25%), but the difference was not statistically significant. This suggests that both methods may have similar efficacy in preventing morphological defects. Detachment of the attachments was minimal in both groups, with only one observed in the experimental group (3.8%) and two in the control group (8.3%).