In this article, we review the recent history of the development of dental CAD/CAM systems for the fabrication of crowns and fixed partial dentures (FPDs), based on our 20 years of experience in this field. The current status of commercial dental CAD/CAM systems developed around the world is evaluated, with particular focus on the field of ceramic crowns and FPDs. Finally, we discuss the future perspectives applicable to dental CAD/CAM. The use of dental CAD/CAM systems is promising not only in the field of crowns and FPDs but also in other fields of dentistry, even if the contribution is presently limited. CAD/CAM technology will contribute to patients' health and QOL in the aging society.

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A review of dental CAD/CAM: current status and future perspectives from 20 years of experience.

Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appropriate, the authors have added their opinions and guidance.

Emerging Ceramic-based Materials for Dentistry

Clinical evaluation of all-ceramic crowns fabricated from intraoral digital impressions based on the principle of active wavefront sampling

Advances in digital impression technology and manufacturing processes have led to a dramatic paradigm shift in dentistry and to the widespread use of computer-aided design/computer-aided manufacturing (CAD/CAM) in the fabrication of indirect dental restorations. Research and development in materials suitable for CAD/CAM applications are currently the most active field in dental materials. Two classes of materials are used in the production of CAD/CAM restorations: glass-ceramics/ceramics and resin composites. While glass-ceramics/ceramics have overall superior mechanical and esthetic properties, resin-composite materials may offer significant advantages related to their machinability and intra-oral reparability. This review summarizes recent developments in resin-composite materials for CAD/CAM applications, focusing on both commercial and experimental materials.

Resin-composite Blocks for Dental CAD/CAM Applications

With the techniques of computer-aided design and computer-aided manufacturing (CAD/CAM) being applied in the field of prosthodontics, a concept of intraoral digital impressions was put forward in the early 1980s. It has drawn comprehensive attention from dentists and has been used for dental prosthesis fabrication in a number of cases. This new digital impression technique is expected to bring about absolute digitization to the mode of prosthodontics. A few published articles have indicated that dental prostheses fabricated from intraoral digital impressions have exhibited remarkable advantages over those from conventional impressions in several respects. The present review discusses intraoral digital impression techniques in terms of the following aspects: (1) categories and principles of intraoral digital impression devices currently available; (2) operating characteristics of the devices; and (3) comparison of the manipulation, accuracy, and repeatability between intraoral digital impression and conventional impression.

Intraoral Digital Impression Technique: A Review

Evaluation of the marginal fit of three margin designs of resin composite crowns using CAD/CAM.

Brittleness index of machinable dental materials and its relation to the marginal chipping factor.

Objective This study compared the marginal gap, internal fit, fracture strength, and mode of fracture of CAD/CAM provisional crowns with that of direct provisional crowns. Material and Methods An upper right first premolar phantom tooth was prepared for full ceramic crown following tooth preparation guidelines. The materials tested were: VITA CAD-Temp®, Polyetheretherketone “PEEK”, Telio CAD-Temp, and Protemp™4 (control group). The crowns were divided into four groups (n=10), Group1: VITA CAD-Temp®, Group 2: PEEK, Group 3: Telio CAD-Temp, and Group 4: Protemp™4. Each crown was investigated for marginal and internal fit, fracture strength, and mode of fracture. Statistical analysis was performed using GraphPad Prism software version 6.0. Results The average marginal gap was: VITA CAD-Temp® 60.61 (±9.99) µm, PEEK 46.75 (±8.26) µm, Telio CAD-Temp 56.10 (±5.65) µm, and Protemp™4 193.07(±35.96) µm (P 0.05). Conclusions CAD/CAM fabricated provisional crowns demonstrated superior fit and better strength than direct provisional crowns.

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Comparative in vitro evaluation of CAD/CAM vs conventional provisional crowns

Evaluation of the marginal integrity of ceramic copings with different marginal angles using two different CAD/CAM systems

This article reports the results of a follow-up study conducted to investigate students' perceptions about a blended learning health informatics course that combined online and traditional classroom instruction. The course is taught to five different groups of students at the School of Clinical Dentistry of the University of Sheffield each academic year: first-, third-, and fourth-year dental students, dental hygiene and therapy students, and postgraduate dental students. The goal of the study was to determine the impact of the modifications made to the course after the first year of implementation. To accomplish this goal, students' perceptions of this blended learning course were compared after the first and second implementations. The methodology used for this study was action research. The data were collected using three processes: questionnaires were used to collect contextual data from the students taking the course; a student-led, nominal group technique was used to collect group data from the participants; and a non-participant observer technique was used to record the context in which certain group and individual behaviors occurred. Depending on group assignment, between 41.5 and 91.5 percent of students believed that the blended-learning course had added to their skills. The online learning environment was perceived as a useful resource by 75 percent of students in four of the five student groups, but only 45 percent of the fourth-year dental students indicated it was a useful resource. The perceived lack of sufficient online support material was one of the main concerns of the students at the nominal group evaluation sessions. The non-participant observer technique identified different engagement levels among the student groups. Discernible differences were identified, with improvement in some areas and a decline in others compared to a previous evaluation. The change in the delivery method influenced the students' comprehension of the material negatively and the learning environment positively, but did not influence online collaboration among students.

Effrosyni Tsitrou

Papers

Evaluation of the marginal fit of three margin designs of resin composite crowns using CAD/CAM.

Brittleness index of machinable dental materials and its relation to the marginal chipping factor.

Comparative in vitro evaluation of CAD/CAM vs conventional provisional crowns

Evaluation of the marginal integrity of ceramic copings with different marginal angles using two different CAD/CAM systems

A blended learning course taught to different groups of learners in a dental school: follow-up evaluation.