[Clinical effectiveness and challenges of digital tooth preparation guidance protocols]

Tooth preparation, as an irreversible surgical procedure, critically determines the long-term efficacy of dental restorations. Traditional preparation techniques, heavily reliant on operators' unaided visual estimation and empirical skills, suffer from inherent subjectivity and the inability to quantitatively verify preparation dimensions. These limitations render them inadequate to meet the sub-100-micron linear precision required for contemporary minimally invasive and esthetic restorations, which often feature maximum preparation depths below 1 mm. Emerging digital solutions, such as depth-specific preparation guides based on target restorative space analysis, have achieved reported preparation accuracies of approximately 50 μm by integrating arithmetic calculations and real-time verification of preparation depth as the pivotal geometric parameter. Further advancements, including real-time intraoral scanning-based preparation monitoring systems, are now being applied to ultra-thin and extreme-thin veneer restorations, offering a more precise and efficient paradigm for depth control. To comprehensively evaluate the efficacy of current digital tooth preparation protocols, this article systematically compares digital guidance technologies with conventional methods across three dimensions: time efficiency, economic cost, and clinical efficacy. It critically examines the synergistic use of visual magnification tools, emphasizing the necessity of concurrently addressing" visual clarity" and "enhancement of manual skill stability and precision". Notably, the target restorative space (TRS)-guided digital preparation technique under dental microscopy employs preparation depth as the master geometric parameter throughout multi-stage workflows. By combining microscopic visualization with rigid depth-specific guides, this method enables real-time verification of preparation depth, achieving unprecedented intraoperative precision. The integration of next-generation non-contact high-precision intraoral scanning systems further elevates accuracy from the sub-100-micron level to a tens-of-microns precision scale, paving the way for ultra-precise tooth preparation. These innovations in digital guidance systems not only redefine clinical standards but also herald the evolution of "digitally guided prosthodontics"as a transformative frontier in restorative dentistry.