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Purpose: To evaluate the scanning strategies affecting the accuracy of virtual interocclusal records (VIR) in partially edentulous arches using an intraoral scanner in vitro. Methods: A reference model of a partially edentulous arch with implant analogs in positions 45,46 and 47 was constructed. Six pairs of 1-mm diameter metal beads were placed on the gingival tissue as markers for measurement. Four scanning strategies were tested: Quadrant-arch Scan (group 1), Quadrant-arch Scan with Auxiliary occlusal devices (AOD) (group 2), Full-arch Scan (group 3), Full-arch Scan with AOD (group 4). The model was digitalized with a lab scanner as a reference and 15 scans were obtained for each group. The accuracy of VIR was assessed by comparing the experiment data to the reference digital model. Results: The mean surface deviations of VIR for Groups 1–4 were 89.4 ± 105.2 μm,95.6 ± 132.8 μm,152.3 ± 159.7 μm and 107.6 ± 138.2 μm respectively. Quadrant-arch scans resulted in lower errors of VIR than full-arch scan (P < 0.001). There was a significant interaction between the AOD and scanning span (P = 0.017). The Quadrant-arch scan with AOD (group 2) produced the least error in the distally extended edentulous area. Conclusions: Quadrant-arch scans showed better accuracy of VIR than full-arch scans across all tooth positions. The combination of AOD and quadrant-arch scan further enhances VIR accuracy in distally extended edentulous areas. [ABSTRACT FROM AUTHOR]

Abstract Purpose To evaluate the scanning strategies affecting the accuracy of virtual interocclusal records (VIR) in partially edentulous arches using an intraoral scanner in vitro. Methods A reference model of a partially edentulous arch with implant analogs in positions 45,46 and 47 was constructed. Six pairs of 1-mm diameter metal beads were placed on the gingival tissue as markers for measurement. Four scanning strategies were tested: Quadrant-arch Scan (group 1), Quadrant-arch Scan with Auxiliary occlusal devices (AOD) (group 2), Full-arch Scan (group 3), Full-arch Scan with AOD (group 4). The model was digitalized with a lab scanner as a reference and 15 scans were obtained for each group. The accuracy of VIR was assessed by comparing the experiment data to the reference digital model. Results The mean surface deviations of VIR for Groups 1–4 were 89.4 ± 105.2 μm,95.6 ± 132.8 μm,152.3 ± 159.7 μm and 107.6 ± 138.2 μm respectively. Quadrant-arch scans resulted in lower errors of VIR than full-arch scan (P

Objectives: This study aimed to compare the accuracy of implant‐level conventional and digital impressions for atrophied maxillary ridges. Materials and Methods: Twelve participants with atrophied edentulous maxillary ridges received six implants. Six months later and after soft tissue maturation around healing abutments, a control cast was constructed using the final passive restoration for each patient. Two types of implant‐level impression techniques were carried out for each patient: (1) conventional (splinted open‐tray) impression technique and (2) digital impression technique. For both techniques, scan bodies were labeled from the most distal implant on the left side (A, B, C, D, E, and F) and scanning was made. Accuracy of both techniques was measured using in vitro (two‐dimensional and three‐dimensional) and in vivo (clinical) methods. Two‐dimensional methods include measurement of the difference in linear distances AB, AC AD, AE, and AF. Geomagic software was used to assess the three‐dimensional deviation between the two impression techniques using the superimposition of standard tessellation language files. The incidence and percentage of nonpassive frameworks and framework misfits of final restorations for both types of impression techniques were assessed using the single screw test. Results: For all distances, digital impressions recorded significantly higher deviation from control measurements than conventional impressions. The highest two‐dimensional linear deviation was noted for AF distance and the lowest difference was noted for AB distance. For all scan bodies, digital impressions recorded significantly higher three‐dimensional deviation than conventional impressions. The highest three‐dimensional deviation was noted with scan bodies C and D. Digital impressions recorded a significantly higher incidence of nonpassive frameworks and framework misfits than conventional impressions. [Correction added on 11 June 2024, after first online publication: In the preceding sentence, "digital impressions" was changed to "conventional impressions" in this version.] Conclusion: Within the limitations of this study, it could be concluded that the conventional implant‐level impression technique showed greater in vitro and in vivo accuracy than the digital impression technique when used for full‐arch maxillary fixed restorations on inclined implants. [ABSTRACT FROM AUTHOR]

Abstract Objectives To compare the crown accuracy and time efficiency of a complete digital workflow, utilizing an auxiliary occlusal device and IO scanning, with a conventional workflow, for multiple implant-supported single crowns. Materials and methods 24 patients with two adjacent posterior implants were included. 12 patients were randomly assigned to digital workflow group, involving intra-oral scanning with an auxiliary occlusal device and manufacture of customized abutments and zirconia single crowns (test group). The other 12 were assigned to the conventional workflow (control group), involving conventional impression and CAD-CAM crowns based on stone casts. Crown scanning was done before and after clinical adjustment using an intraoral scanner. Two 3D digital models were overlapped to assess dimension changes. Chair-side and laboratory times for the entire workflow were recorded and a linear mixed model and Independent-sample t tests were used for the statistical analysis. Results The maximum occlusal deviation was 279.67 ± 112.17 μm and 479.59 ± 203.63 μm in the test and control group, respectively (p

The choice of a splinted or nonsplinted implant-supported prosthesis should be based on solid scientific evidence that considers the conditions and needs of each patient. This review elaborates on the factors that directly influence clinical decisions between splinted or nonsplinted dental implants. Digital and manual searches of the published literature were conducted to identify studies that examined splinted prostheses (SPs) and nonsplinted prostheses (NSPs). The search terms used, alone or in combination, were "splinting prosthesis," "nonsplinting prosthesis," "prosthetic design," "stress distribution in dental implant," "implant loading," "implant occlusion," and "crestal bone resorption." Ninety-four studies were selected to compare and address the details emphasized in this study. Thirty-four reported articles were not directly related to restoration design but were reviewed to better understand the influence of mechanical risk factors, finite element analysis limits, and criteria for implant survival and treatment success. There are advantages and disadvantages of splinting implants together. NSPs are the ideal choice because they resemble natural teeth. Splinting a restored implant will cause the implant to appear as part of one unit and is indicated in more compromised situations, unfavorable conditions, or when pontic spaces and cantilevers are needed in implant prostheses. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to determine the relative positioning accuracy of multiple implants utilizing four distinct types of splinting materials. Methods The purpose of this in-vitro study was to compare the precision of four splinting materials in an open tray impression technique in multiple implant situations. Based on the material used for splinting, four groups were made (n = 40)- Group A: Conventional Method, Group B: Prefabricated Pattern Resin Framework, Group C: Prefabricated Metal Framework, Group D: Light Cured Pattern Resin, these groups were compared with the master model. A heat-cured clear acrylic resin and a master model were constructed. A pilot milling machine drill was used to drill four parallel holes in the anterior and premolar regions, which were later labeled as A, B, C, and D positions from right to left. Then, sequential drilling was carried out, and four 3.75‑mm diameter and 13-mm long ADIN implant analogs with internal hex were placed in the acrylic model using a surveyor for proper orientation. The impression posts were then manually screwed to the implant analogs using an open tray, and they were secured to the implants using 10 mm flat head guide pins with a 15 N.cm torque. 10 Open tray polyether impressions were made, and casts were poured. Each splinting method’s distortion values were measured using a coordinate measuring machine capable of recordings in the X-, Y-, and Z-axes. Comparison of mean distances for X1, X2, and X3 was made using the Kruskal-Wallis test, and Pairwise comparison was done using Post Hoc Tukey’s Test. Results The differences between the groups were significant when assessing the distances X1, X2, and X3 (p 0.05). Conclusions All splinting materials produced master casts with measurements in close proximity to the reference model. However, prefabricated pattern resin bars splinting showed the highest accuracy among the studied techniques. The most recent splinting techniques using prefabricated metal framework and light-cure pattern resin showed similar accuracy.

In breast reconstruction following a single mastectomy, the surgeon needs to choose between tens of available implants to find the one that can reproduce the symmetry of the patient's breasts. However, due to the lack of measurement tools this decision is made purely visually, which means the surgeon has to order multiple implants to confirm the size for every single patient. In this Letter, the authors present an augmented reality application, which enables surgeons to see the shape of the implants, as 3D holograms on the patient's body. They custom developed a two-chamber implant that can gain different shapes and be used to test the system. Furthermore, the system was tested in a user study with 13 subjects. The study showed that subjects were able to do a comparison between real and holographic implants and come to a decision about which should be used. This method can be quicker than the traditional way and eliminates sizer implants from the process. Further advantages of the method include the use of a more accurate, user-friendly device, which is easily extendable as new implants that are on the market can be easily added to the system dataset.

Introduction: Fracture of shaft and ipsilateral neck of femur is a challenging problem to orthopaedics surgeons. The treatment is often difficult, and there are many protocols for the management of these fractures. Objectives: To assess the efficiency of multiple implants method for management of ipsilateral fracture neck and shaft femur using plate and screws or retrograde nail for femoral shaft fractures and cannulated screws or sliding hip screw for femoral neck fracture, evaluate the efficiency of reconstruction nail as a single implant method for management of fracture both neck and shaft femur as well as to compare the results of two management methods. Material and Methods: A total of 20 adult patients with ipsilateral femoral neck and shaft fractures were included in our study. Standard radiographs were obtained. Patients were divided into single implant group (Group I; 10 patients) and multiple implants group (Group II; 10 patients). All patients were followed prospectively for a minimum of 1 year. Fracture union was confirmed radiologically, and functional evaluation was done as per Harris Score. Results: 70% of both groups achieved successful fracture union with the remaining 30% with either nonunion, malunion or necrosis of the femoral head but with non- significant difference between both groups. Conclusion: Upon comparing single versus multiple implants methods, equivalent results, were clinically and radiologically obtained with both techniques. However, it is difficult to draw a definite conclusion as the number of cases is relatively small. A study with a larger population scale probably gives a definite conclusion. [ABSTRACT FROM AUTHOR]

One of the most important determinants of the fit of an implant restoration is the accuracy of the impression. An accurate implant level impression would entail the correct three-dimensional recording of the implant position within the arch to the adjacent teeth and soft tissues and the transfer of this relation to the working cast. The complexity of the impression procedure is increased in cases involving multiple implants. Numerous techniques of impression making for multiple implants have been documented in the literature. This paper describes a quick, simple and cost effective technique of impression making procedure for a clinical case involving multiple implants. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to compare the accuracy of different direct implant impression techniques for edentulous arches with multiple implants. Methods: Five experimental groups (n = 5) were assembled. Experimental models were created by a direct splinted technique (EG2 to EG5) and a non-splinted technique (EG1). In EG2 and EG3 synOcta impression copings were splinted with an acrylic resin bar, and in EG4 and EG5 with a light-curing composite resin bar. In EG3 and EG5 the resin bars were sectioned, while the other experimental groups were not. Three-dimensional discrepancies were measured by a computerized coordinate measuring machine. Distortion values among the groups were analysed using one-way repeated measures ANOVA. The post hoc Tukey's test was then performed for multiple comparisons. Results: The highest accuracy was obtained in EG2 (mean deviation: 12.70 μm). The acrylic bars demonstrated less deviation (12.70 μm and 22.71 μm) from the master model than the light-curing composite resin groups and the non-splinted group (41.09 μm). The post hoc Tukey's test showed no significant difference among the groups when the effect of splint design on accuracy was investigated. Conclusions: For situations where impressions of multiple implants are to be made, splinting impression copings with acrylic resin demonstrate superior results than the non-splinted technique and splinting with light-curing composite. [ABSTRACT FROM AUTHOR]

In breast reconstruction following a single mastectomy, the surgeon needs to choose between tens of available implants to find the one that can reproduce the symmetry of the patient's breasts. However, due to the lack of measurement tools this decision is made purely visually, which means the surgeon has to order multiple implants to confirm the size for every single patient. In this Letter, the authors present an augmented reality application, which enables surgeons to see the shape of the implants, as 3D holograms on the patient's body. They custom developed a two-chamber implant that can gain different shapes and be used to test the system. Furthermore, the system was tested in a user study with 13 subjects. The study showed that subjects were able to do a comparison between real and holographic implants and come to a decision about which should be used. This method can be quicker than the traditional way and eliminates sizer implants from the process. Further advantages of the method include the use of a more accurate, user-friendly device, which is easily extendable as new implants that are on the market can be easily added to the system dataset.