Carla Vidal‐Ponsoda

Purpose: Passive fit in implant‐supported complete‐arch prostheses is the key to long‐term success. The aim of this in vitro, proof‐of‐concept study was to examine whether torque/time graphs generated from a surgical motor during the prosthetic screw insertion process show consistent patterns of digitally controlled angular and linear misfits in monolithic zirconia frameworks. Materials and Methods: Eight high‐strength, low‐translucency zirconia blocks, suitable for complete‐arch prosthetic frameworks, were manufactured and assessed. A standardized edentulous model with three implants was used. The two outer prosthetic screws were screwed and secured, whereas the central screw was tightened using a surgical motor, allowing real‐time acquisition of torque/time graphs for each framework. Framework design was intentionally modified to introduce controlled degrees of angular and linear misfit. The resulting torque/time curves were analyzed to identify graphical patterns associated with each specific level of angular and linear misfit. Results: Torque/time graphs were recorded for all zirconia frameworks. The control sample showed a gradual rise in torque to 13.7 N cm with a stable 5 revolutions per minute (rpm), indicating optimal passive fit. Frameworks with small linear (≤80 µm) or angular (≤1.9°) discrepancies displayed similar, clinically acceptable patterns. Linear misfits beyond 120 µm resulted in delayed torque progression and higher resistance, whereas at 160 µm, screw engagement failed, with torque plateau at 2.0 N cm. Angular misfits greater than 2.9° resulted in irregular torque curves and early mechanical tension. Deviations of 3.8° produced unstable torque, reduced rpm, and incomplete screw seating. At 4.8°, no engagement of the screw occurred, with torque values less than 2.0 N cm. Conclusions: Within the limitations of this in vitro, proof‐of‐concept study, interpreting torque/time graphs obtained during prosthetic screw insertion may represent a promising non‐invasive approach to detect misfits in zirconia complete‐arch frameworks. This suggests a feasible approach to improve the objectivity of passive fit assessment in clinical practice, although further validation, both in vitro and in vivo, is recommended.

Background/Objective: Diagnostic trial restorations play a crucial role in restorative dentistry by allowing clinicians to evaluate aesthetics, function, and phonetics before finalizing definitive restorations. These restorations facilitate communication between patients, clinicians, and dental technicians, ensuring treatment alignment and predictable outcomes. The accuracy of transferring diagnostic trial restorations to the oral cavity is essential to maintain the integrity of the planned design. Various fabrication techniques, including conventional silicone matrices and computer-aided design/computer-aided manufacturing (CAD-CAM)-based methods, have been developed to improve transfer precision. However, there is limited evidence directly comparing their dimensional accuracy. This randomized in vivo study aimed to evaluate and compare the accuracy of four commonly used techniques—condensation silicone, addition PVS silicone, transparent PVS silicone, and CAD-CAM combination matrices—by assessing their linear and volumetric discrepancies. Methods: Twenty patients requiring aesthetic rehabilitation of their anterior maxillary teeth participated. The sequence of matrix usage was determined through randomization. Four techniques for transferring diagnostic trial restorations were evaluated: (1) condensation silicone matrix, (2) addition polyvinyl siloxane (PVS) silicone matrix, (3) transparent PVS silicone matrix, and (4) CAD-CAM combination matrix. Dimensional accuracy was assessed by comparing intraoral scans (IOSs) of the transferred restorations to the original diagnostic wax-up. Linear discrepancies were measured at four buccal landmarks (cervical, medial, lower medial, and incisal), and volumetric deviation was evaluated using reverse engineering alignment software. Results: Significant differences were observed among the groups in both linear and volumetric discrepancies (p < 0.05). The CAD-CAM combination matrix showed superior volumetric accuracy, with minimal deviations from the diagnostic wax-up. The addition PVS silicone matrix demonstrated consistent linear accuracy, particularly at the cervical and medial landmarks. The condensation silicone matrix exhibited moderate performance across both linear and volumetric accuracy. The transparent PVS silicone matrix showed the highest variability, with greater volumetric deviations. Conclusions: The study highlights that the choice of matrix material and technique significantly impacts the dimensional accuracy of diagnostic trial restoration transfers. The CAD-CAM combination matrix and the addition PVS silicone matrix demonstrated superior advantages compared to the other techniques. Clinicians should consider the specific requirements of each case, including accuracy and ease of use, when selecting a transfer technique for aesthetic rehabilitations.

Autotransplanted teeth in the maxillary anterior region should be restored or reshaped as soon as possible for functional and esthetic reasons as well as the well‐being of the patient. However, such tooth restorations are frequently not carried out immediately after tooth transplantation because the process could have a negative impact on the healing process. The development of a simple, immediate, and atraumatic esthetic interim restoration would be of great benefit to both the clinician and patient and address all the concerns caused by immediately preparing the tooth postoperatively and cementing a permanent restoration. This report describes the use of CAD‐CAM technology to create poly (methyl methacrylate) veneers preoperatively that can be cemented extraorally on the extracted donor tooth for the immediate and interim recontouring of autotransplanted anterior teeth.

Objective: To evaluate the volumetric changes on occlusal surface of computer‐aided design and computer‐aided manufacturing (CAD‐CAM) occlusal devices fabricated following a fully digital workflow after occlusal adjustment, compared to those fabricated with an analog workflow.Materials and Methods: Eight participants were included in this clinical pilot study, receiving two different occlusal devices fabricated with two different workflows, fully analog and fully digital. Every occlusal device was scanned before and after the occlusal adjustments to compare the volumetric changes using a reverse engineering software program. Moreover, three independent evaluators assessed a semi‐quantitative and qualitative comparison using visual analog scale and dichotomous evaluation. The Shapiro–Wilk test was performed to validate normal distribution assumption, and a dependent t‐Student test for paired variables was used to determine statistically significant differences (p‐value < 0.05).Results: The root mean square value was extracted from the 3‐Dimensional (3D) analysis of the occlusal devices. The average values of the root mean square were higher for the analogic technique (0.23 ± 0.10 mm) than the digital technique (0.14 ± 0.07 mm) but the differences were not statistically significant (paired t‐Student test; p = 0.106) between the two fabrication techniques. The semiquantitative visual analog scale values between the impression for the digital (5.08 ± 2.4 cm) and analog (3.80 ± 3.3 cm) technique were significant (p < 0.001), and statistically significant differences values were assessed for evaluator 3 compared to the other evaluators (p < 0.05). However, the three evaluators agreed on the qualitative dichotomous evaluation in 62% of the cases, and at least two evaluators agreed in 100% of the evaluations.Conclusions: Occlusal devices fabricated following a fully digital workflow resulted in fewer occlusal adjustments, as they could be a valid alternative to those fabricated following an analog workflow.Clinical Significance: Fabricated occlusal devices following a fully digital workflow could have some advantages over analog workflow such reduce occlusal adjustments at delivery appointment, which can result in reduced chair time and therefore increased comfort for the patient and clinician.