Benedikt Schneider

Objective: This in vitro study aimed to evaluate and compare the transfer accuracy of implant impression systems utilizing transfer caps for the closed‐tray technique across five different implant systems, with the open‐tray (pick‐up) technique serving as a reference. Materials and Methods: Six bone‐level implants from different manufacturers (SIC Invent, BEGO, Bredent, Camlog, and Straumann) were placed in a 3D‐printed custom‐designed master model. The master model with the inserted implants and the attached scan bodies served as the reference model. The implant master model was duplicated 10 times by means of conventional impressions. Based on these impressions, the master models were fabricated. Finally, closed‐tray impressions using transfer caps were taken ten times for each system, and one system (SIC Invent) was also tested using the open‐tray technique. Polyether impression material and standardized laboratory protocols were used throughout. The accuracy of the impressions was evaluated through 3D superimposition using Final Surface software, comparing master models to a reference model. Deviation measurements were statistically analyzed using rank‐based ANOVA. Results: No statistically significant differences were found in the transfer accuracy among the five closed‐tray systems. Similarly, the closed‐tray technique showed comparable precision to the open‐tray technique. Conclusion: Closed‐tray implant impressions using transfer caps can achieve transfer accuracy on par with the open‐tray technique. These findings support the potential clinical reliability and reproducibility of closed‐tray systems across multiple implant manufacturers.

Objectives: Two-dimensional intraoral radiographs often obscure canals due to superimposition, especially in mandibular molars with complex anatomy. This cone-beam computed tomography (CBCT) study identified the horizontal beam angles at which first and second molar canals overlap and derived clinically applicable angulations for enhanced canal separation.Methods: Eighty-five CBCT datasets from 100 patients met the inclusion criteria, yielding 318 mandibular molars (160 first, 158 second). Using ImageJ, absolute horizontal overlap angles (α) were measured to determine the corresponding theoretical separation angles defined as δ* = 90° – α. Separability was modeled across horizontal beam angulation increments from −45° to +45° in five steps, and Wilson’s 95% confidence intervals were computed. Group comparisons used the Mann-Whitney U and independent t-tests (p ≤ 0.05)Results: Minimal mesial beam angulations for effective canal separability (δ* = 90° − α) ranged from approximately 7° to 15° for mesial roots and approximately 10° to 13° for distal roots. No significant mesial differences were observed between first and second molars (p > 0.30). Distal roots of second molars exhibited significantly higher angulations (p = 0.003 coronal, p < 0.001 apical). Mesial canals achieved ≥95% separability at approximately 25° and ≥99% at approximately 35°; distal canals required approximately 30° and approximately 40°.Conclusions: A mesial beam angulation of 30° to 35° provides probable canal differentiation in mandibular molars, separating mesial canals in ≥99% and distal canals in ≥95% of cases. This range refines previous recommendations and supports the as low as reasonably achievable (ALARA) principle.

Background/Purpose: The study aimed to analyze the dimensions and width-to-length ratios of the maxillary anterior teeth in young native Cambodian adults and to assess their relationship with the golden proportion, symmetry, and sexual dimorphism. Materials and Methods: Maxillary study casts of 193 eligible Cambodian subjects, aged 18 to 25 years, were retrospectively evaluated. The width and length of their maxillary anterior teeth were measured using a digital caliper. Descriptive statistics, independent-samples t-test at 95% confidence intervals, Kolmogorov-Smirnov, Shapiro-Wilk, and Kruskal-Wallis tests were performed to analyze the data. Results: There was a high level of similarity between first and second quadrant measurements. Females showed slightly higher standard deviations for central incisors and lateral incisors than males across most ratios, indicating more variability in the width-in-length ratios for females. Males exhibited significantly greater tooth dimensions than females. The following results showed statistical significance with p < 0.05 and 95% confidence intervals. The mean crown width of the central incisors was 8.16 mm in males (CI: 8.03–8.29) and 7.87 mm in females (CI: 7.78–7.96). For the lateral incisors, the mean crown width was 6.69 mm in males (CI: 6.53–6.85) and 7.64 mm in females (CI: 7.43–7.85). The width-to-length ratio of the central incisors was higher in females (mean = 0.88; CI: 0.86–0.91) compared with males (mean = 0.87; CI: 0.84–0.89). Overall, proportional relationships remained consistent across genders. The golden proportion guideline was not applicable, as observed ratios ranged from 0.90 to 1.67 (all below 1.618), and RED values exceeded 80%. The null hypothesis was rejected due to the significant gender differences found in tooth dimensions and width-to-length ratios. Conclusions: There was no significant difference in maxillary anterior tooth dimensions for the right and left sides among the Cambodian population. Males had statistically larger teeth than females. Width-to-length ratios were greater in females for central incisors; however, the proportional relationships between the genders remained relatively consistent. The golden proportion and RED proportions did not exist within this population. A smaller size characterizes Cambodian dentition compared to that of other ethnic groups. Finally, these results can serve as an indicator for planning customized esthetic treatment in Cambodians. Future studies with larger sample sizes are needed to ensure the representation of the whole Cambodian population.

Background/Objectives: Intraoral (IO) radiographs are critical for endodontic diagnostics, yet conventional orthoradial imaging often results in superimposition, limiting the visibility of individual root canals. Maxillary first premolars pose challenges due to their anatomical characteristics and positioning within the dental arch. This study aimed to retrospectively analyze cone-beam computed tomography (CBCT) data to determine the horizontal X-ray beam angulations for maxillary first premolars at which root canals overlap and neighboring tooth superimposition occur, providing clinically relevant guidance for optimizing IO radiographic techniques. Methods: CBCT scans from 85 patients were analyzed using ImageJ software to measure the angles at which maxillary first premolar root canals overlap or become obscured by adjacent teeth. The mean angles for canal overlap and neighboring tooth superimposition were determined. Statistical analysis was performed using SPSS Version 29.0, and the level of significance was set to 5%. Results: The mean angle for root canal overlap was 93.56° (±10.08). The angles at which neighboring teeth began to superimpose were 124.38° (±9.91) for the distal contour of the canine and 63.46° (±9.38) for the mesial root contour of the second premolar. No significant differences were observed between apical and coronal measurements for root canal overlap but tapering of the roots led to significant differences in neighboring tooth superimposition (p < 0.05). Conclusions: A mesial beam shift within a calculated safe corridor (98.5–129.5°) optimizes canal separation without superimposition from adjacent teeth. For ideal visualization, a mesial angulation close to 40° is recommended. These findings support improved IO radiographic techniques while minimizing the risk of retakes in adherence to the ALARA principle.

Purpose Precise implant placement is essential for optimal functional and aesthetic outcomes. Digital technologies, such as computer-assisted implant surgery (CAIS), have improved implant outcomes. However, conventional methods such as static and dynamic CAIS (dCAIS) require complex equipment. This study examined the usefulness of smartphone-based augmented reality (AR) for CAIS based on the value addition regarding angulation and positioning of pilot drillings and the potential for training dental students. Methods An in vitro model was created to mimic dental scenarios using three-dimensional datasets. Smartphone technology and AR application (app)-based intraoral tracking were used for dCAIS. The app allowed real-time visualization of implant planning, superimposition of three-dimensional models, and alignment of surgical instruments. Forty dental students performed four pilot drillings each; two were performed freehand, whereas two were performed using the app. The angulation and position of the prepared implant bed preparation were statistically analyzed. Results Implant angulation was significantly better in the AR-guided group than in the unguided group; however, no significant difference was observed in the implant position. Conclusions Smartphone-based AR techniques for dCAIS are easily accessible in dental implantology. This may be advantageous for training dental students and potentially improving clinical outcomes, particularly the angulation of dental implants.

Background: Traditional methods for palatal expansion using fixed appliances often face limitations in comfort and aesthetics. In comparison, aligner therapy has limitations, particularly regarding maxillary expansion. The aim of this study is to examine the biomechanical properties regarding the wire diameter and bending of different stainless steel wires to evaluate their potential for incorporation into maxillary aligner therapy. Materials and Methods: Three rectangular stainless steel wires (0.016″ × 0.022″, 0.017″ × 0.025″, and 0.019″ × 0.025″) were tested for mechanical expansion forces in the intermolar region, comparing non-tooth-shaped bent wires (A groups) and tooth-shaped bent wires (B groups). Using a Z010 testing machine (ZwickRoell GmbH and Co. KG, Ulm, Germany), expansion forces were measured at 1 mm intervals over a 5 mm distance, with 15 samples analyzed per group. Statistical analyses included the Shapiro–Wilk test for normal distribution, the Mann–Whitney U test, which revealed significant results (U = 225, p < 0.001), and the Kruskal–Wallis test, which indicated significance (H = 39.130; df = 2; p < 0.001). Results: Tooth-shaped bent wires exhibited significantly lower expansion forces than non-tooth-shaped bent wires for all tested wire types. This difference was most notable in wires with larger transverse profiles (0.019″ × 0.025″), where the tooth-shaped bent wires displayed a marked reduction in mechanical load capacity. Specific force measurements for non-tooth-shaped wires ranged from 760.61 ± 79.51 mN at 1 mm of deformation to 2468.46 ± 66.27 mN at 5 mm of deformation, while tooth-shaped wires ranged from 116.80 ± 3.74 mN to 1979.49 ± 23.23 mN. Conclusions: These findings suggest that non-tooth-shaped bent wires offer a more efficient and uniform expansion potential for maxillary movements due to their stable elastic properties. Clinically, integrating non-tooth-shaped stainless steel wires into aligner therapy may provide a viable method for maxillary expansion, supporting both first- and second-order movements in orthodontic treatment. Further research is needed to explore the integration of such wires for effective maxillary expansion in aligner therapy.

Introduction: Digital panoramic radiographs (DPRs) are used in dental practice as the first diagnostic tool for the initial detection of head and neck regions soft-tissue calcifications. The aim of this study was to use a self-developed application (App) to evaluate the ability of dental students at different levels of training to examine known DPRs with different soft-tissue calcification. Methods: A total of known 100 DPRs with (n=50) and without (n=50) calcification were independently evaluated by four groups: preclinical, first clinical and last clinical dental students, and dentists with less than or equal to 1 year of professional experience in the same time (15 min) and examination conditions. Unity software was used to develop the examination App, which allowed to mark areas with calcifications on the DPRs. The data were statistically analyzed between the groups (significance level: P<0.05) for every location, and the detection rate was calculated as a percentage of detected calcifications. Results: Results revealed that the overall detection rate of calcifications in all groups was 29.17%. Dentists exhibited the highest detection rate (36.46%), followed by the last- (29.69%), first- (32.29%), and preclinical (15.10%) students. Conclusion: These findings suggest that clinical experience plays a role in the correct detection of soft-tissue calcifications in DPRs. However, deficiencies in radiological training during dental education may contribute to diagnostic errors. As these can become life-threatening risks, the results highlight the need for early training in the dental curriculum to improve diagnostic performance and minimize possible diagnostic errors.

Introduction and importance: Extraction of mandibular third molars can lead to complications such as chronic sclerosing osteomyelitis (CSO), an inflammatory bone marrow disease that tends to progress. CSO involves the cortical plates and often the periosteal tissues and is caused by a variety of microorganisms, including Corynebacterium spp. The treatment of chronic osteomyelitis (CO) and CSO remains challenging, as there is no universal treatment protocol. This case report investigated whether jaw bone that has healed from chronic sclerosing osteomyelitis can be considered healthy bone when planning dental implants. Case presentation: A 21-year-old Caucasian woman developed CO and CSO after third molar surgery. Clinical discussion: A combination of alveolar ridge bone resection, extraction of teeth 47–32, and long-term specific antibiotic therapy against Corynebacterium spp. was administered. An attempt at preprosthetic alveolar ridge reconstruction with an anterior superior iliac crest bone graft resulted in graft failure and the patient refused further harvesting procedures. Implantation in the intraforaminal zone also resulted in the loss of two implants after loading. Finally, inferior alveolar nerve transposition resulted in the successful reimplantation of two implants, which were fully functional almost 11 years later. Conclusion: This case report presents the treatment history of this patient. With a longitudinal observation period of greater than 20 years, the results of this case demonstrate the successful treatment of bone with CO, CSO, and Corynebacterium spp. infection. Following the removal of infected bone, radical debridement, and long-term antibiotic therapy, bone health was restored.

Introduction . Extensive comminuted fractures are associated with tooth loss that ultimately leads to dimensional changes in the hard and soft tissues of the alveolar ridge. Reconstruction of the lost mandibular anterior ridge is very complex due to the natural curvature of the region. Case Presentation . In this case report, the combination of the modified shell technique with autologous bone plates and the guided bone regeneration (GBR) technique was performed on an 18‐year‐old patient after a comminuted fracture, to ensure new bone formation in the anterior ridge with a natural curvature. After the treatment progressed without complications, three dental implants were placed. Annual cone beam computed tomography (CBCT) images were obtained and evaluated using the GNU Image Manipulation Program (GIMP© 2.10). This allowed measurements of the buccal and lingual bone around the implants, showing the annual bone loss in a twelve‐year observation period. Discussion . The treatment of the comminuted fracture and the combination of the modified shell technique with autologous bone plates, the GBR technique, and implant placement can be considered successful. The three dental implants were osseointegrated in 2010, with the buccal bone level averaging 1.31 mm below the implant shoulder and the lingual bone level 1.57 mm above the implant shoulder. In 2021, the measurements showed a bone loss of 0.99 mm at the buccal implant shoulder and 0.69 mm at the lingual implant shoulder. Conclusion . The combination of the modified shell technique with autologous bone plates and the GBR technique is a reliable method to ensure new bone formation in the anterior ridge. The use of CBCT is an excellent method to evaluate bone resorption around dental implants, but due to minimal bone resorption in the observation period, an annual CBCT examination is exaggerated.

Autologous tooth transplantation is the transplantation of an erupted, partially erupted, or unerupted tooth from one site to another in an individual. This is expected to maintain alveolar bone volume through physiological stimulation of the periodontal ligament (PDL). Tooth transplantation can be used for the closure of oroantral communication. As a simple, useful, and minimally invasive method, it should be considered a surgical option when a donor tooth is available in indicated cases. Herein, the authors report the case of a 20-year-old female patient whose left permanent maxillary first molar had to be extracted due to a longitudinal fracture and radicular cyst in the maxillary sinus floor. After the extraction, tooth 28 was exposed through an osteotomy and positioned in the gap. Nineteen years later, the autologous grafted tooth 28 could no longer be retained due to massive external resorption and was replaced by an implant. Human PDL stem cells can differentiate into bone-, fiber-, and cementum-forming cells and have the potential to build a PDL complex. Therefore, care must be taken to avoid damaging the PDL of the donor tooth during extraction. Autotransplanted teeth are expected to retain the alveolar bone volume. This case demonstrates the use of a transplanted tooth 28 for the treatment of a maxillary defect caused by the extraction of tooth 26 and removal of a radicular cyst. External resorption and regeneration of the bone of the maxillary sinus floor around the transplanted tooth occurred after 19 years.