International Journal of Computerized Dentistry

Aim: Although many fields of dentistry allow digital processes today, analog procedures are still widely used. The present cross-sectional pilot study aimed to provide insights into the digitalization of dental practices using the example of Hesse. Materials and methods: Between April and June 2022, 4840 active practicing dentists registered by the State Dental Association of Hesse were invited via email to fill out an online questionnaire regarding their technical requirements in dental practice, dental treatment procedures, and attitude toward digitalization in dentistry. Demographic questions were asked. Besides descriptive statistics, correlations were analyzed (P 0.05). Results: Questionnaires of 937 dentists (279 females, 410 males, 4 inter/diverse, 244 no answers; mean age of 51.4 ± 10.4 years) were examined, representing a response rate of 19.36%. In the area of practice administration and dental radiography, the majority of the dentists surveyed were already working digitally, which is predominantly assessed as a positive development. One third of the respondents stated that they already used an intraoral scanner for dental treatments, but for indications mainly limited to minor restorations. However, many dentists rated the use of social media accounts and telemedicine rather negatively. Conclusion: Within the limitations of this cross-sectional pilot study, it was shown that many dental treatments were still being performed by analog processes. However, 60% of the participants planned the digitalization of their dental practices within the next 5 years, which indicated a clear shift from analog to digital dentistry. Keywords: analog–digital conversion, CAD/CAM, dental practice pattern, dentistry, dentists, digital technology, intraoral scanner, organization and administration, real world data on dentistry, surveys and questionnaires

Aim: To assess the agreement rates of dental records derived from intraoral scan-based digital 3D models (3DM) and 3DM plus panoramic radiographs (3DM+PAN-X) compared with clinical findings. Materials and methods: Based on the 3DM/3DM+PAN-X of 50 patients undergoing supportive periodontal therapy (SPT), 10 remote raters (inexperienced in using intraoral scanners [IOSs] or 3DM) assessed for each site of the dental scheme (32 sites) whether a tooth was missing (M), filled (F), restoration- and caries-free (H), replaced by an implant (I), or decayed (D). Remote records were compared with the clinical reference record of each patient at tooth level. The clinical records were assessed by an experienced dentist who supplemented the clinical findings with information from available radiographs and the patient records to define the clinical reference record. Results: The agreement rates for 3DM/3DM+PAN-X at tooth level were: M: 93%/94%, F: 84%/88%, H: 92%/92%, I: 65%/96%, D: 29%/29%. The overall agreement rate (odds ratio [OR]) was 88% for the 3DM-based dental records (14,093 of 16,000 entries true), and 91% for 3DM+PAN-X (14,499 of 16,000 entries true). Using 3DM for dental record assessment, posterior teeth had higher odds of correct findings compared with anterior teeth (maxillary jaw OR = 2.34, mandibular jaw OR = 1.27). Conclusions: The remote detection of healthy, missing, and filled teeth as well as implants by raters inexperienced in using IOSs or 3DM showed a high agreement rate with the clinical findings. The additional evaluation of PAN-X increased the agreement rate significantly for implants. Thus, the remote assessment of dental records using 3DM+PAN-X had a high accuracy when applied in SPT patients with low caries activity. Keywords: dental record remote assessment, digital dentistry, digital imaging, full-arch impression, intraoral scanners, supportive periodontal therapy

Aim: To develop a periodontal disease prediction (PDP) software program and a patient-based gingival recession simulator for clinical practice with the aim of improving the oral hygiene motivation of patients with periodontal problems. Materials and methods: The developed PDP software has three components: a) A data loading window (DLW), b) A three-dimensional mouth model (3DM), and c) a periodontal attachment loss indicator (PLI). The demographic and clinical examination details of 1057 volunteers were recorded to the DLW. An unsupervised machine learning K means clustering analysis was used to categorize the data obtained from the study population and to identify the periodontal risk groups. An intraoral scanner was utilized to capture the direct optical intraoral data of the patients, which was transferred to the 3DM. The intraoral model underwent two algorithm steps to obtain a recessed model: First, the gingival curves separating the gingiva and tooth were extracted using a Dijkstra’s algorithm. Then, the limit curves determining the boundaries of the recessed regions in the intraoral model were obtained using the gingival curves. Results: Study participants were divided into three different periodontal risk categories: low- (n = 462), medium- (n = 336), and high-risk (n = 259) groups. The gingival curves separating the gingiva and tooth were extracted, and recessed models were obtained and given inputs for the expected amount of recession via the here-proposed method/algorithm. Furthermore, the user can also demonstrate the gingival recession gradually via the slider method incorporated into the developed program. Conclusions: A user-friendly computer-based periodontal risk estimation tool that is also a patient-specific gingival recession simulator was developed and presented for clinical use by dentists. Keywords: computer-aided design, Dijkstra’s algorithm, gingival recession, oral hygiene motivation

Aim: The aim of the present study was to measure the surface roughness of monolithic chairside CAD/CAM zirconia materials to evaluate the influence of milling speed on the ability to create a clinically smooth surface. The null hypothesis was that there would be no significant difference in the surface roughness of different zirconia materials based on the speed of milling. Materials and methods: All test samples were milled from four different monolithic CAD/CAM zirconia blocks: Cerec Zirconia, Cerec Zirconia+, Cerec MTL Zirconia (all three Dentsply Sirona), and Katana Zirconia (Kuraray Noritake). Four different dry milling speeds – Super Fast/Good, Super Fast/Very Good, Fast, and Fine – were used to dry mill the specimens in a Cerec Primemill (Dentsply Sirona) milling unit. A 3D measuring laser microscope (OLS4100 LEXT; Olympus) was used to measure surface roughness. Results: Analysis of variance (ANOVA) was used to analyze the surface roughness data for each material and milling speed. There was a significant difference for milling speed (P 0.05) but not between the zirconia materials (P > 0.05). Conclusions: Based on the limitations of the present study, the milling speed was found to influence the surface roughness of dry milled and sintered zirconia, with slower speeds resulting in smoother surfaces. The largest improvement in surface roughness occurred between the Super Fast and Fast milling speeds, with a smaller incremental improvement in surface roughness with Fine milling in the Primemill. All recorded surface roughness values were within the expected range of values to be able to efficiently hand polish a clinically acceptable surface finish. Keywords: ceramics, Cerec, dry mill, mill speed, surface roughness, zirconia

Aim: Mandibular single-implant overdenture is a well-established treatment modality for the management of completely edentulous patients. The use of CAD/CAM printing technology to fabricate complete dentures and overdentures is burgeoning. The present randomized controlled clinical trial (RCT) aimed to clinically evaluate 3D-printed single-implant overdentures and compare their outcomes with those of overdentures fabricated using conventional techniques. Materials and methods: An RCT was designed. Twenty-eight participants were randomly allocated into two equal groups. Participants in the control group received conventionally fabricated single-implant overdentures, while those in the intervention group received digital light processing-printed single-implant overdentures. An evaluation was conducted to assess implant survival and success rates as well as overdenture survival and success, along with the measurement of maximum bite force (MBF) over a 1-year follow-up period. Data were collected and subjected to statistical analysis. Statistical significance was determined using a two-sided P value with a threshold of less than 0.05. Results: The 3D-printed group had higher implant survival (100%) and success (92.8%) rates compared with the conventional group (85.7% survival, 85.7% success). Overdenture survival and success rates were 100% in the 3D-printed group and 78.6% in the conventional group. Both groups showed a significant increase in MBF at the 3-, 6-, and 12-month follow-ups (P 0.001). The 3D-printed group demonstrated a statistically significant improvement in MBF compared with the conventional group (P 0.001). Conclusions: 3D-printed mandibular single-implant overdentures may represent an alternative to conventionally fabricated ones. Keywords: 3D printing, bite force, denture survival, implant survival, overdenture

Medical imaging technology has greatly improved over the last 40 years. A good example of this is the improved 3D reconstruction capabilities of computed tomography (CT), which enable photorealistic reconstructions. This technological advancement has also taken place in the computer industry, and the development of modern graphics cards has fueled progress in video games. In art, many of the techniques used to improve three-dimensionality have been known for centuries. At first sight, these fields seem unrelated, but there is actually considerable confluence. The present article focuses on three areas: fine arts, video games, and medical imaging. The art section illustrates different drawing techniques used to create three-dimensionality. The video games section shows the development of video games from the 1980s to the present day. Finally, the medical imaging section focuses on the first 3D radiography reconstructions in the 1980s and the improvements to the present day. Contemporary video games and 3D reconstructions of CT scans enable photorealistic impressions of 3D anatomical structures. An important factor is shadow casting and light, which has been known in fine arts for centuries. The effect on the observer of photorealistic 3D reconstructions in video games and in medical imaging can largely be explained by the knowledge of 3D techniques used in drawings and paintings. Keywords: 3D reconstruction, anatomy, fine arts, radiology, video games

Aim: Fracture of abutment teeth with telescopic crown-retained removable partial dentures (TCDs) is a common cause of failure for this prosthetic restoration. In many cases, a telescopic crown (TC) can only be refitted after post and core (PC) treatment due to an insufficient retention surface. Furthermore, if the root canal has an elliptic cross-sectional area or the coronal defect is severe, customized cast post and cores (CPCs) are still the therapy of choice. Nevertheless, the disadvantage of CPCs is longer chair time due to the need for a second appointment for insertion. In addition, the mechanical properties of the alloy do not match with dentin, leading to a higher risk of root fracture. In such cases, CAD/CAM PCs fabricated in a fully digital chairside workflow can accelerate the treatment and decrease the risk of root fractures by using materials with matching mechanical properties. Materials and methods: The case series presented in this article includes 12 patients who were treated with TCDs and experienced abutment tooth fracture that required PC treatment to refit TCs. The post space preparation as well as the TCDs were scanned in less than 10 min for the fabrication of CAD/CAM PCs out of a fiber-reinforced CAD/CAM composite. Conclusions: With the presented fully digital chairside workflow, PC fabrication can be accelerated because a second appointment is not needed for customized PCs. The presented workflow might be an alternative to that for conventional PCs to refit TCs after abutment tooth fracture. The CAD/CAM-fabricated PC offers mechanical properties close to dentin and can be fabricated chairside in a short period of time. Keywords: abutment tooth fracture, CAD/CAM, fiber-reinforced composite, intraoral scanner, post and core, telescopic denture