OBJECTIVE: The present study evaluated the effects of the root portion design, segment (middle vs. apical), and part (die vs. cast) on the trueness of three-dimensional (3D)-printed removable die-cast complex.
METHODS: The trueness of apical and middle segments of the root portion of 45 3D-printed removable dies and casts with three different root portion designs (n = 15) was assessed using a metrology-grade computer program. The three removable dies and cast designs (root form [RF], conical [CON], and cylindric [CYL]) were created using professional computer-aided manufacturing computer programs (DentalCAD 3.1 Rijeka, and InLab CAD 22.0), and manufactured using stereolithographic 3D printer (Form3; FormLabs, Somerville, MA). Subsequently, the 3D-printed removable dies and casts were scanned by a single operator with an intraoral scanner (PrimeScan; Dentsply Sirona, Charlotte, NC), and their respective standard tessellation language files were aligned and compared to master reference files in a metrology-grade computer program (Geomagic Control X; 3D systems, Rock Hill, NC). The root mean square (RMS) values of the middle and apical segments for each removable die and cast were calculated and analyzed using a mixed model including a repeated measure 3-way analysis of variance (ANOVA) and post-hoc stepdown Bonferroni-corrected pairwise comparisons (α = 0.05).
RESULTS: A statistically significant 3-way interaction between factors was detected, suggesting that the part (removable die or alveolar cast) and their design affected the RMS values of their apical and middle root portion segment. (p = 0.045). The post-hoc analysis identified significant differences between RMS values of the apical segments of the CON and CYL removable dies (p = 0.005). Significant differences were observed between the middle and apical segments of the CON (p < 0.001) and RF removable die designs (p = 0.004). No statistically significant differences were noticed between the RMS of the different alveolar cast designs (p > 0.05). Significant differences were detected between the apical and middle segments of the same alveolar cast design (p < 0.05).
CONCLUSIONS: For the manufacturing trinomial and 3D printing strategy used in the present study, the interaction of the part, design, and segment affected the trueness of removable dies and alveolar casts. The trueness was higher on the middle segment on removable dies and alveolar casts in all designs used, except for CYL removable dies, where the trueness difference between segments was small. Higher trueness values may be achieved with designs with simple apical segment geometries.

UNASSIGNED: To determine the effect of experience and tooth location on the finish line width and angle of crown preparations performed by undergraduate students.
UNASSIGNED: Eighty full metal crown preparations on typodont teeth were divided into four groups: Group 1: 20 preparations performed on mandibular first molar in the first semester. Group 2: 20 preparations performed on mandibular first molar in the second semester. Group 3: 20 preparations performed on mandibular second molar in the first semester. Group 4: 20 preparations performed on mandibular second molar in the second semester. All prepared teeth were scanned, and the finish line width and angles were measured at 8 different locations. Paired t-test in the SPSS software was used to compare and determine the effect of experience and tooth location on the students\' performance.
UNASSIGNED: There was a statistically significant difference in the mandibular first molar finish line width between the first and second semesters for the same student in the distal, distolingual, and mesiobuccal areas of the tooth. There was a statistically significant increase in finish line width between first and second molars in the distobuccal, distal, distolingual, lingual, and mesial side of the tooth. Regarding the finish line angle, there was a statistically significant difference between the first and second semesters on the distal side of the tooth. There was a statistically significant increase in finish line angle between first and second molars in the distobuccal side of the tooth.
UNASSIGNED: As students gain more experience in different types of tooth preparations, they tend to produce a wider finish line than that recommended for full metal crown preparation. The tooth location in the mouth influences the width and angle of the finish line hence the more inaccessible areas on the tooth have a wider finish line.

Lasers are employed in all fields of modern dentistry nowadays, including both surgical and non-surgical dental procedures. Prosthodontics, a branch of dentistry, has also embraced lasers as an invaluable addition to conventional methodologies. This helps improve the standard of care for patients and dentists due to its precise excision, quick healing, and enhanced tissue response after surgeries. In prosthodontics, the most commonly used lasers are carbon dioxide, argon, and yttrium-aluminum-garnet (YAG) lasers. Many reviews have been published in the literature regarding the use of lasers in dentistry; however, reviews on the use of lasers in the field of prosthodontics are limited. This review aims to explain the diverse applications and advancements of lasers in prosthodontics. Furthermore, it will highlight the integration of lasers in diagnostic protocols, treatment modalities, and the fabrication of prosthetic restorations.

Sjögren\'s syndrome is a chronic, inflammatory autoimmune disorder characterized by lymphocyte infiltration of the exocrine glands. Notably, the rehabilitation of partially edentulous patients with Sjögren\'s syndrome is limited by the scarce availability of studies that could inform therapeutic modalities and potential challenges during clinical procedures. This case report aimed to present the oral rehabilitation of a patient with Sjögren\'s syndrome who received fixed partial dentures (FPDs). A 28-year-old female patient sought treatment to restore her missing teeth. She was diagnosed with Sjögren\'s syndrome by a rheumatologist adhering to the revised version of the European criteria proposed by the American-European Consensus Group and was on a medication regimen including prednisolone, hydroxychloroquine, pantoprazole, pilocarpine, and tear substitutes to manage her condition. The final treatment plan consisted of extractions, management of gingivitis, post-and-core restorations, and a 2 mm vertical dimension increase with the placement of 15 porcelain-fused-to-metal (PFM) crowns and 4 short-span bridges. The patient underwent regular clinical and radiographic evaluations every 3 months since June 2020. Throughout this period, the fixed prostheses, teeth, and periodontal tissues demonstrated remarkable stability and exhibited no complications. This three-year case study provides evidence that meticulous planning and clinical execution can facilitate successful oral rehabilitation in young edentulous patients with Sjögren\'s syndrome. Tooth-supported fixed prostheses can effectively restore oral function and aesthetic appeal in these individuals, provided they undergo more frequent dental examinations than the general population and maintain a cooperative attitude throughout the treatment process.

This clinical report introduces a novel clinical technique to create a 3D virtual patient for transferring the edentulous maxillary arch position with maxillomandibular relationship by using a facial scan device and an intraoral scanner and omitting CBCT imaging.

Computer-aided design and computer-aided manufacturing systems enable digital designing and 3-dimensional (3D) printing of definitive casts with removable dies. However, the fit of the removable dies should be without interferences for their accurate positioning in the cast. Given that the accuracy of additive manufacturing depends on design- and manufacturing-related factors, verifying the accuracy of the position of 3D-printed removable dies in their cast is essential to fabricate positionally accurate definitive prostheses, which would enable minimal or no laboratory and clinical adjustments. This dental technique article presents a straightforward approach to verify the seating of a 3D-printed removable die by using verification matrices made of a polyvinylsiloxane interocclusal registration material.

The effectiveness of newly developed elastomeric polymer hybrid siloxane (PVES), which combines the properties of polyethylene (PE) and polyvinyl siloxane (PVS) elastomers, has been a subject of interest in recent studies. This study aimed to assess the physical properties of hybrid PVES materials by analyzing existing data from recent studies on this topic.
A systematic literature search was conducted to retrieve peer-reviewed articles published up to February 5, 2023. The population, intervention, comparison, and pertinent outcomes were specified under the PICO framework. The primary data analysis was performed in Microsoft Excel, while statistical analysis used Meta-Essentials.
Of the 1152 articles assessed, 14 met the inclusion criteria. The meta-analysis of the selected studies indicated that polyether (PE) and polyvinyl siloxane (PVS) were highly correlated (two-tailed p-values of 0.000 and 0.001, respectively) with the improved tensile strength of vinyl polyether siloxane (PVES) with a significantly positive effect size. Similarly, the hydrophilic characteristics of PVES were significantly improved compared to those of PE and PVS. PE was a significant contributor to the hydrophilic characteristics of PVES, with a two-tailed p-value of 0.000. The effect size was highly positive for hydrophilicity but showed high heterogeneity. It was also observed that the dimensional accuracy of PVES was comparable to those of PE and PVS, with no statistically significant differences among the three materials.
PVES showed promising features, with improved tensile strength and hydrophilic characteristics compared to those of PE and PVS.

This article presents the outcomes of prosthetic oral rehabilitation using CAD/CAM telescopic bar overdentures in patients with oral cancer (n = 3), severe facial trauma (n = 2), or various syndromes (n = 1), all suffering from severe tissue deficits and requiring complex and comprehensive oral rehabilitation. The aim was to assess the durability and functionality of implant-retained prosthetic structures, ensuring easy oral hygiene and minimizing specialized follow-up needs. The data for this study were sourced from a retrospective cohort at Helsinki University Hospital. The prosthetic reconstruction encompassed the Atlantis 2in1 and the Createch removable telescopic systems. Thus, 40 implants were placed (4 to 7 per patient), with prosthetic structures in the maxilla (n = 4 patients), in the mandible (n = 1), and in both jaws (n = 1). Two patients experienced no complications, two patients had part of the acrylic resin break, and one patient experienced loosening of the bar structure. All complications associated with prosthetic structures were successfully managed, and none of the implants were lost. The follow-up time ranged from 7 to 126 months. This rehabilitation is proved to be an effective solution for patients with complex oral conditions, facilitating both functional restoration and ease of maintenance. These findings underscore the importance of individualized treatment approaches in cases of tissue deficits.

BACKGROUND: In fixed prosthodontics, simulators are essential to students for a progressive transition from preclinical to clinical condition. With the 3D printing technology, we developed resin bars allowing students to better visualise by motor chunking technique. Main objectives of this work were to describe this teaching methodology used in preclinic among different promotions of second, third and fourth dental years and to evaluate students\' feedback.
METHODS: Two hundred seventy resin strips were digitally designed and printed in resin. All participants from second, third and fourth had to fulfil a User Experience Questionnaire (UEQ) after the preclinical work. The scales of this questionnaire covered the complete impression of the user experience. Both classical aspects of usability (efficiency, insight and reliability) and aspects of user experience (originality, stimulation) were measured.
RESULTS: For the second dental years, \'Attractiveness\', \'Stimulation\' and \'Novelty\' were considered \'Excellent\'. For the third dental year, novelty average was considered as \'Excellent\'. For the fourth dental year, \'novelty\' was considered as \'Good\'.
CONCLUSIONS: The resin plates used in this study are original and stimulating for the students, especially for the second-year dental students who found the exercises useful for their learning. This method can also be used by creating scenarios close to the clinical situations encountered in dentistry departments (more dilapidated teeth, preparation of inlays, post and core, etc.). This 3D printed simulation model is not intended to replace the Frasaco® models but is a complement to the learning process.

This patient series reports the outcomes of CAD/CAM prosthetic reconstructions in patients with cleft lip and palate (n = 9, aged 27 to 76) who have experienced significant failure with conventional restorative and fixed prosthodontic treatments. The objective of the protocol is to establish a functional and patient-friendly prosthetic structure for individuals with unilateral/bilateral cleft lip and palate (UCLP/BCLP) while minimising the requirement for specialised follow-up care in the cleft unit. The study data were obtained from a retrospective cohort at Helsinki University Hospital. Prosthetic reconstructions were performed using CAD/CAM bar structures by the Atlantis 2in1 system or Createch removable telescope structures, supported by four to eight maxillary dental implants. Out of the nine patients, seven experienced no complications. One prosthesis fracture occurred after 16 months due to a design error in the original framework, and one patient experienced failure of osseointegration in a dental fixture (specifically, one fixture out of the eight maxillary implants in this patient). In total, 56 implants were successfully placed. The maxillary dentition of elderly patients with cleft lip and palate often poses challenges due to periodontal and reconstructive issues. An implant-supported CAD/CAM bar with a removable telescope suprastructure offers an easily maintained and functional solution for dental rehabilitation.