## 4 Discussion
The current clinical standards for rubber cup polishing are ambiguous, emphasizing low pressure and speed, and short, intermittent contact between the rubber cup and the tooth [10]. Without standard clinical guidelines, precisely controlling the pressure and speed of the rubber cup on the tooth surface is challenging and can potentially lead to excessive damage after polishing, as demonstrated in our study results. Moreover, teeth with high caries activity or existing cracks can experience accelerated enamel damage if polished without accurate assessment [42]. Therefore, dentists must thoroughly assess the condition of the tooth and accurately set the rotation speed of the rubber cup before proceeding with polishing to minimize damage. Additionally, developing patient-specific protocols that include the use of fluoride toothpaste, professional fluoride application, and other treatments to maximize the recovery of the tooth surface, along with adjusting the recovery interval of the tooth surface, is necessary [42; 43]. While the findings of our study contribute significantly to the understanding of enamel damage due to various rubber cup rotational speeds, some limitations must be acknowledged. First, the extent of damage based on conditions applied during polishing, such as the rubber cup pressure, duration of use, and abrasive particle size, could not be assessed. Further studies are warranted to address these limitations and identify precise setting conditions for rubber cup polishing, because these factors are also critical in determining the extent of enamel damage. Understanding these factors will enable us to develop refined guidelines for dental practitioners, ensuring effective and safe polishing procedures. Second, the scope of our investigation was confined to the utilization of a single type of rubber cup in the rubber cup polishing procedures. Given the extensive array of rubber cups available in clinical practice, each with distinct physical properties, the generalizability of our findings could be constrained. Thus, it is imperative for further studies to explore the implications of using various types of rubber cups on polishing outcomes. Third, while enamel damage encompasses a range of conditions including early caries, cracks, cervical abrasion, and enamel hypoplasia, our study focused solely on early caries and cracks. Further studies should encompass a broader spectrum of enamel conditions to formulate comprehensive treatment guidelines that are applicable to diverse clinical scenarios. Fourth, our experimental design did not include interventions such as water spray that could mitigate the abrasion caused by rubber cup polishing. This decision was made to reflect the typical conditions present in clinical settings where rubber cup polishing is performed. Future studies should explore and assess methods to minimize the adverse effects of rubber cup polishing on tooth surfaces and enhance the safety and effectiveness of this common dental procedure. Fifth, our study relied on in vitro models, which, although providing controlled conditions, did not fully replicate the complex biological and mechanical interactions present in an in vivo setting. Particularly, our models did not consider the enamel's potential for recovery through remineralization by saliva. Studies that closely mimic the actual oral environment, utilizing designs that account for the remineralizing effects of saliva, are required to provide a more realistic assessment of enamel damage and recovery. Furthermore, the transition from in vitro to in vivo studies is a critical next step. Conducting longitudinal clinical trials will allow for the observation of the real-time effects of rubber cup rotational speeds on enamel, which is essential for translating findings directly into clinical practice. Finally, our study did not investigate the long-term effects of tooth polishing on the enamel's capacity for remineralization and the durability of the polished surfaces over time.