Journal of Dental Medicine

Background and Aims: The exact placement of impression copings in making accurate prosthesis is very important. In some cases, the implants need to be placed deeply subgingival, which could reduce the direct vision and ultimately reduce the precision of impression copings and subsequently, delivered prosthesis. This would be the cause of multiple complications such as delivery of ill-fitting prosthesis. The aim of this study was to evaluate the effect of the dental implant placement depth on the accuracy of impression coping connection by students.

Materials and Methods: This in-vitro and experimental study was conducted by 50 senior dental students. Four implants at different depths (0, 2, 4 and 6 mm) were placed in a model. After learning how to mount impression coping on implants, the students were asked to mount impression copings on all four implants. The samples were examined by an experienced prosthodontist using a magnifier with 4x magnification. Data were analyzed by statistical Cochran test (P<0.05(.

Results: The proper adapting rate of transfer copings, in subgingival implants with the depth of 0, 2, 4 and 6 mm were 100%, 62%, 58% and 20%, respectively. Statistically significant differences were observed between all groups (P<0.001).

Conclusion: The results showed that there was an inverse relationship between the increasing depth of the implants in the gingiva and the dentist’s ability to connect the impression copings properly.

Background and Aims:  Digital impression systems have transformed prosthodontics by enhancing accuracy, efficiency, and patient comfort. Despite these advantages, their clinical adoption remains constrained by technical and operational challenges. This review aimed to critically evaluate the limitations of digital impression systems in the field of fixed and removable prosthodontics.
Materials and Methods:  Relevant literature was searched in PubMed, Scopus, Web of Science, and Google Scholar databases. Scientific sources were reviewed for their contribution to understanding the limitations and challenges of digital impression systems in the field of fixed and removable prosthodontics. The selected studies were then analyzed descriptively, and their findings were interpreted to provide a comprehensive overview of the current challenges, limitations, and future perspectives of this technology.
Resulrs: Findings indicated that although digital impression systems could demonstrate high accuracy and reproducibility under controlled laboratory conditions, their clinical performance  has been influenced by multiple factors. Operator experience, scanning strategy, and image stitching significantly could affect data accuracy. Environmental conditions such as moisture, light, and temperature might further compromise outcomes. Patient-related variables, including arch morphology, tooth preparation, implant presence, and restorative materials, also contributed to variability in results. Additionally, technical factors such as scanner design, software version, and scanning head size would play an imporant role.
Conclusion:  Evidence suggests that while digital systems may outperform conventional impressions in controlled settings, clinical limitations persist. Therefore, optimized protocols and integration of digital and conventional techniques may enhance reliability and improve prosthodontic outcomes.