The question about the numerical value and quantitative data transfer of implant prosthodontics-orom experience guidance to digital guidance / 华西口腔医学杂志

The correct implant site design and placement are the basic clinical techniques that must be known for implant restoration. For a long time, most implants have been placed by free hands, and the choice of site is mostly dependent on the accumulation of long-term experience of the surgeon. The selection of implant site guided by this experience analogy logic is often based on the surgeon's level of experience,which often makes it very easy to produce complications related to the implant restoration of the incorrect site. In contrast, a clinical program using digital guidance and real-time measurable verification has emerged based on the restoration-oriented implantation concept, which marks the formation of an accurate, measurable and verifiable whole-process digital implant prototype. Furthermore, from the perspective of surveying, the numerical requirements that digital implant restoration relies on are actually incomplete to the four elements of measurement, which leading to the doubts about its authenticity. This article will question the numbers in implant restoration, and conduct a preliminary demonstration, and propose a new reliable actual measurement and verification method of the correct location and the numerical requirements of the restoration space and a new clinical program that relies on numbers from the perspective of the evolution of digital restoration, guided implantology and actual measurement technology. And this article further discusses the current mainstream implant restoration technology based on experience analogy which cannot effectively support the whole process of digital implant restoration and provides a new logical cognitive basis for the final realization of the entire process of digital implant restoration.

Questions about the numerical value and quantitative data transfer of tooth preparation-from experience guidance to digital guidance / 华西口腔医学杂志

Tooth preparation is a common operation in dental clinical practice. This procedure is irreversible and invasive from the point of view of tooth preservation. Conditions of the abutment tooth, treatment methods, and restoration materials for target restoration affect tooth preparation. To achieve the goals of tooth tissue preservation, dental pulp protection, and periodontal health, dentistry professionals agreed on the importance of minimizing the amount of tooth reduction. The foundations for realizing this consensus are as follows. First, the available restoration materials with improved comprehensive performance need less target restoration space. Next, teeth can be prepared under a digital guide, and the real-time measurement of restoration space can be verified due to the invention of digital technologies for the analysis of the quantity and shape of the prepared tooth and tooth measurement. Moreover, guiding methods for preparation have been developed from freehand operation under the naked eye based on accumulated personal experience to digital-guidance jointing microscope. These innovations indicate the creation of a prototype of guided prosthodontics that is precise and applies real-time measurement throughout the process of tooth preparation. From the perspective of the evolution of digital, guided, and micro prosthodontics, this article raised seven questions about the numerical value and quantitative data transfer of tooth preparation and evaluated the authenticity of existing numerical requirements from the perspective of the four elements of measurement. Identifying unified measuring methods and developing measuring tools with a precision of hundred or ten microns will be the key to solving the problem about the authenticity of numerical measurement. Furthermore, this paper summarizes the methods of how to control tooth reduction and explains in depth why the currently dominant tooth preparation technology, which is based on empiricism, cannot effectively achieve the goals in digital prosthodontics. Therefore, we strongly call for rebuilding the digital foundation of prosthodontic treatment immediately.

Immediate precision of the digital osteotomy template in the digital stackable template: a clinical study / 华西口腔医学杂志

OBJECTIVES@#This study aimed to evaluate the immediate accuracy of the digital osteotomy template in the digital stackable template.@*METHODS@#From November 2018 to January 2020, 4 patients with dentition loss were selected from the Prosthodontics Department, West China Stomatological Hospital. All patients met the conditions for immediate planting and immediate restoration. Owing to the lack of vertical target-restoration space, the implantation plan included intraoperative osteotomy. According to the preoperative cone beam CT (CBCT) data, combined with aesthetic digital smile design (DSD) analysis, virtual wax design, and so on, the ideal bone plane design was performed. According to the virtual osteotomy plane, the virtual implantation plan was designed, and then the digital stackable template assuming osteotomy template, implantation guide, and temporary restoration were made and 3D printed. Osteotomy was performed under the guidance of digital osteotomy template during the operation. The preoperative CBCT and postoperative CBCT of all patients overlapped, the deviation between the actual osteotomy and the ideal osteotomy was calculated, and the angle deviation between the postoperative bone plane and the ideal bone plane was measured.@*RESULTS@#The ave-rage volume deviation between the postoperative design and the ideal one was 492.94 mm³, accounting for 21.21% of the preset osteotomy volume. The average deviation between the postoperative osteotomy and the ideal osteotomy in four patients was 0.024 8 mm. The average angle between the postoperative bone plane and the ideal bone plane was 6.03°.@*CONCLUSIONS@#The displacement deviation of virtual osteotomy design and the actual osteotomy one under the guidance of digital osteotomy template in the digital stackable template are highly consistent with the original design. Thus, this clinical technique is worth popularizing, accurate, and quantifiable.

Minimal invasive microscopic tooth preparation based on endodontic, periodontal and functional health / 华西口腔医学杂志

Tooth preparation is the primary and core operation technique for dental esthetic restoration treatment, due to its effect of providing restoration space, bonding interfaces and marginal lines for dental rehabilitation after tooth tissue reduction. The concept of microscopic minimal invasive dentistry put forward the issue of conducting high-quality tooth preparation, conserve tooth-structure, protect vital pulp and periodontal tissue simultaneously. This study reviewed the concepts, physiology background, design and minimal invasive microscopic tooth preparation, and in the meantime, individualized strategies and the two core elements of tooth preparation (quantity and shape) are listed.

Application of 3D printing in aesthetic oral rehabilitation / 华西口腔医学杂志

3D printing technology can be used in prosthodontics to obtain detailed structures. The technique offers a possible supersession for the most conventional restorations technologies. Contemporary aesthetic restorations encounter difficulties in the consistency between the analysis and design stages and the clinical implementation stage. 3D printing transfers aesthetic designs to customize the finial restoration fabrication, which could be an appropriate optimization to the aformentioned problem. Meanwhile, 3D printing technology can be employed to manufacture target restoration space guide (TRS guide), which is a blueprint for the aesthetic ceramic restorations and presents a general functional and aesthetic situation of patients. The guidance provided by TRS guide ensures precision and minimal invasive operation in aesthetic restorations. These new digital technologies have revolutionized aesthetic rehabilitation. This paper introduces the application of 3D printing in aesthetic oral rehabilitation.