Computer-assisted implant placement and full-arch immediate loading with digitally prefabricated provisional prostheses without cast: a prospective pilot cohort study

Background Immediate loading of implant-supported full-arch rehabilitations has become routine practice when treating edentulous patients. The combination of static computer-aided implant surgery (s-CAIS) and digital prosthetic workflow could eliminate several treatment steps and facilitate prostheses delivery. The aim of this study is to evaluate the 1-year results of digitally prefabricated polymethyl methacrylate (PMMA) provisional prostheses without a cast for full-arch computer-assisted immediate loading. Materials and methods A digital pre-operative treatment planning was realized for all patients: dental implants and screw-retained abutments were selected in the planning software and two surgical templates were fabricated for each patient. The first template was mucosa or teeth-supported to drill the holes for fixating pins, while the second template was placed after raising a full-thickness flap and was supported by pins as well as soft or hard tissue distal support. Furthermore, based on the surgical planning, interim prostheses were digitally designed and milled of PMMA resin blocks with subsequent pink resin veneering. Osteotomies and implant placement were performed through the surgical guides and all implants were immediately loaded with prefabricated full-arch interim prostheses directly connected to titanium copings with a flowable resin. Results A total of 55 dental implants were placed in ten patients. In all cases, interim prostheses allowed the insertion of titanium copings without the need of access hole enlargement or adaptation. All the prostheses had 1 year of functional loading to simulate the long provisional phase. No screw loosening occurred at the first removal of the prostheses after implant osseointegration. No fracture occurred during the whole period. After 1 year, the mean marginal bone loss level was 0.37 ± 0.06 mm, while the implant survival rate was 98.18% (n=54/55), with just one implant failing but not affecting final prosthesis delivery to the patient. Conclusions Within the limitations of the present study, the authors concluded that digitally prefabricated provisional prostheses for full-arch immediate loading with s-CAIS could be a valid alternative treatment modality. Milled PMMA restorations proved to be durable enough during the long provisional phase, without prosthetic complications.

Two-Year Follow-Up of 4-mm-Long Implants Used as Distal Support of Full-Arch FDPs Compared to 10-mm Implants Installed after Sinus Floor Elevation. A Randomized Clinical Trial

Background: In edentulous patients, bone resorption cannot allow the installation of standard implants and it is demanded to use short implants in the residual alveolar bone or longer implants in grafted bone. Aim: To compare the survival and bone level changes of standard plus short 4-mm implants used as distal support of a maxillary full-arch fixed dental prostheses (FDPs) with standard (10-mm) implants placed in association with a bilateral sinus floor augmentation procedure. Material and Methods: Full-arch FDPs supported by six implants were randomly placed in both groups. In the control group, all implants were 10 mm long and 4.1 mm in diameter. The distal implant in both sides of the maxilla was installed after 4 months from bilaterally sinus floor elevation. In the test group (short group), the distal implant in both sides of the maxilla was 4 mm long and 4.1 mm in diameter. No sinus floor elevations were performed in the test group. Clinical assessments and X-rays were taken at prosthesis delivering and after 6, 12, 18, and 24 months. Patient-reported outcome measures (PROMs) were also evaluated before surgery and after 6, 12, and 24 months. Results: The changes over time of the bone level for the short implants were −0.01 ± 0.11 mm, −0.04 ± 0.13 mm, −0.17 ± 0.29 mm, and −0.28 ± 0.37 mm after 6, 12, 18, and 24 months from prosthesis delivering, respectively. For the standard implants, bone changes were −0.21 ± 0.33 mm (p = 0.103), −0.30 ± 0.32 mm (p = 0.023), −0.40 ± 0.37 mm (p = 0.144), and −0.54 ± 0.49 mm (p = 0.128), respectively. A statistically relevant difference was found only at 12 months after loading between the two groups. Conclusions: Similar results on implant survival rate and marginal bone loss were observed for the short and standard implants, placed in association with a bilateral sinus floor augmentation procedure, used as distal support of a maxillary full-arch FDP. A statistically relevant difference was found only at 12 months after loading between the two groups (p = 0.023).

Decision-making self-efficacy mediates the peer support–career exploration relationship

We explored the mediating effect of decision-making self-efficacy in the relationship between undergraduates' perceived career-related peer support and career exploration. Participants were 650 junior and senior undergraduates from 6 public universities in Shanghai, China. The key results were as follows: (1) career information and suggestion, emotional support, and peer role models were the 3 dominant factors of career-related peer support; (2) career-related peer support was positively and significantly correlated with career exploration; and (3) career decision-making self-efficacy mediated the relationship between career-related peer support and career exploration. Specifically, career information and suggestion and peer role models provided proximal and distal support, promoting individuals' career exploration not only directly but also indirectly through career decision-making self-efficacy. In comparison, emotional support from peers provided only distal support, promoting individual career exploration indirectly through career decision-making self-efficacy. Theoretical and practical implications of the findings, study limitations, and future research directions are discussed.

Improvement in walking abilities in transfemoral amputees with a distal weight bearing implant

Background:The ability to walk with a prosthesis is the main objective of rehabilitation following amputation, and distance and speed of walking achieved are considered determining factors in amputees’ perception of quality-of-life.Objectives:To assess walking abilities and improvement in gait distance and speed parameters in patients undergoing transfemoral amputation with a femoral implant that allows distal support of the residuum.Study design:Experimental before-and-after study.Methods:Ten transfemoral amputation patients received a titanium implant that allowed distal weight bearing of the residuum within the socket. The post-intervention follow-up period was 14 months. We evaluated the functionality using a 2-min walk test and the physiological cost index.Results:The etiology of amputation was traumatic in six patients (60%). The mean 2-min walk test score was 98.4 ± 19.5 m prior to the femoral implant and 122.5 ± 26.1 m at 14 months ( p < 0.008), representing an improvement of 24.5%. The mean gait speed prior to the femoral implant was 0.82 ± 0.16 and 1.02 ± 0.21 m/s at 14 months ( p < 0.008). The physiological cost index showed no differences ( p < 0.55).Conclusion:The results of this study show an improvement in the distance walked and gait speed in amputees 14 months after having received a femoral implant.Clinical relevanceThis article provides additional insight into the use of a femoral implant that allows distal support of the residuum to improve walking abilities and gait distance and speed parameters in patients undergoing transfemoral amputation, mainly those of vascular origin.

A Pliocene age and origin for the strandflat of the Western Isles of Scotland: a speculative hypothesis

A series of very wide (up to 15 km) raised shore platforms in the Scottish Hebrides are identified and described for the first time and are considered part of a high rock platform shoreline in the western isles of Scotland described by W. B. Wright in his classic Geological Magazine paper a century ago as a ‘preglacial’ feature. Subsequent interpretations suggesting that the platforms were produced during the Pleistocene are rejected here in favour of a speculative hypothesis that the features are part of the well-known strandflat that is extensively developed across large areas of the northern hemisphere. It is argued that the Scottish strandflat developed during the Pliocene and was later subjected to extensive Pleistocene glacial erosion such that only a few areas of platform have survived in the Scottish Inner Hebrides (ice-proximal) while they are well-preserved in the Outer Hebrides (ice-distal). Support for a Pliocene hypothesis is provided by the marine oxygen isotope record for this time interval which points to prolonged periods of relative sea level stability as would be required for the production of such wide features. This hypothesis for the formation of a Scottish strandflat not only provides an elegant explanation for the origin and age of the raised rock platform fragments that occur throughout the western isles of Scotland, but it may also have relevance for other coastal areas of the northern hemisphere (e.g. Norway, Greenland, Alaska) where the strandflat is a well-developed feature.