Standard Implants Research Articles

The Possibilities of Personalized 3D Printed Implants—A Case Series Study

Background and Objectives: Following the most recent software and 3D printing developments, the use of personalized 3D printed orthopedic implants for treatment of complicated surgical cases has gained more popularity. Today, orthopedic problems that cannot be solved with standard implants may be effectively addressed using personalized prostheses. The aim of this study is to present the designing, modeling and production stages of four different personalized 3D printed prostheses and their application in clinical cases of patients who underwent treatment in various anatomical locations with a precisely specified indication for implantation. Materials and Methods: Based on computed tomography scanning, personalized 3D printed prostheses were designed, produced and used in four patients within a period of three to five days after injury or admission. Results: Early term follow-ups demonstrated good to excellent results. Conclusions: Personalized 3D printed prostheses offer an opportunity for a treatment of choice and provide good anatomical and functional results, shortened surgical time, less complications, and high satisfaction in patients with appropriate indications. The method should be considered primarily for patients with large bone defects, or such indicated for resection. Personalized 3D printed prostheses have the potential to become more common and beneficial in the future.

Short Implants versus Standard Implants and Sinus Floor Elevation in Atrophic Posterior Maxilla: A Systematic Review and Meta-Analysis of Randomized Clinical Trials with ≥5 Years' Follow-Up.

Background and objectives: The aim of this systematic review with meta-analysis was to assess the performance of short implants in comparison with standard implants and sinus floor elevation in atrophic posterior maxilla. Materials and methods: The protocol of the study was registered in the PROSPERO database (CRD42022375320). An electronic search on three databases (PubMed, Scopus, Web of Science) was performed to find randomized clinical trials (RCTs) with ≥5 years' follow-up, published until December 2022. Risk of bias (ROB) was calculated using Cochrane ROB. A meta-analysis was performed for primary (implant survival rate, ISR) and secondary outcomes (marginal bone loss, MBL; biological and prosthetic complications). Results: Of 1619 articles, 5 RCTs met the inclusion criteria. The ISR showed a risk ratio (RR) of 0.97 [0.94, 1.00] (CI 95%), p = 0.07. The MBL indicated a WMD of -0.29 [-0.49, -0.09] (CI 95%), p = 0.005. Biological complications showed a RR of 0.46 [0.23, 0.91] (CI 95%), p = 0.03. Prosthetic complications showed a RR of 1.51 [0.64, 3.55] (CI 95%), p = 0.34. Conclusions: The available evidence suggests that short implants might be used as an alternative to standard implants and sinus floor elevation. After 5 years, in terms of ISR, standard implants and sinus floor elevation showed a higher survival rate comparted to short implants, although statistical significance was not achieved. Future RCTs with long-term follow-up are needed to draw a clear conclusion on the advantages of one method over another.

Physiological Femoral Condylar Morphology in Adult Knees-A MRI Study of 517 Patients.

In the age of individualised arthroplasty, the question arises whether currently available standard implants adequately consider femoral condylar morphology (FCM). Therefore, physiological reference values of FCM are needed. The aim was to establish physiological reference values for anterior (ACO) and posterior condylar offset (PCO) as well as for the length of the medial (LMC) and lateral femoral condyles (LLC). The knee joints of 517 patients (mean age: 52.3 years (±16.8)) were analysed retrospectively using MRI images. Medial (med) and lateral (lat) ACO and PCO, as well as LMC and LLC, were measured. All FCM parameters were examined for association with age, gender, side and osteoarthritis. Mean ACOmed was 2.8 mm (±2.5), mean ACOlat was 6.7 mm (±2.3), mean PCOmed was 25.7 mm (±4.6), mean PCOlat was 23.6 mm (±3.0), mean LMC was 63.7 mm (±5.0) and mean LLC was 64.4 mm (±5.0). Except for PCOmed, the mean values of all other FCM parameters were significantly higher in male knees compared to female knees. ACOmed and PCOmed showed significant side-specific differences. There were no significant differences in relation to age and osteoarthritis. The study showed significant differences in FCM side- and gender-specifically in adult knees. These aspects should be considered in the discussion of individual and gender-specific knee joint replacement.

Humerale Knochendefekte in der Revisionsendoprothetik

Revision shoulder arthroplasty is mainly performed with reverse TSA and should consider proper adjustment of the length and the amount of bone loss in humeral reconstruction. Whilst epi-/metaphyseal bone loss can mostly be compensated easily by stemmed standard implants, advanced bone loss exceeding2° requires the support of longer revision stems. Cementless fixation in the intact diaphyseal humerus is recommended in bone loss exceeding2°, preferably with modular revision systems, because cemented reverse revision stems have higher loosening rates in the mid to long-term follow-up. In cases of advanced bone loss3°-4° (more than 6-7 cm), structural humeral allografts should be considered to prevent instability and early loosening. Unfortunately, the access to fresh frozen allografts is very limited due to regulation of the German government in contrast to the situation in the US or Switzerland. Reverse tumor arthroplasty is an option with ahigher complication rate and inferior function even when polyester mesh is used for ingrowth of soft tissues. In bone loss4°-5° the minimal anchorage length is mostly critical due to the curvature of the medullary canal. The fixation of arevision stem is only possible when at least 2-3 widths of the diaphyseal diameter are available. Custom-made implants with flanges or distal locking screws, or bipolar tumor arthroplasty may be required. Additionally, strut allografts can be useful to achieve stable fixation. Two-stage biological reconstruction in impaction-bone-graft or the Masquelet technique are rarely used as asalvage procedure.

Unstable Total Hip Arthroplasty: Should It Be Revised Using Dual Mobility Implants? A Retrospective Analysis from the R.I.P.O. Registry.

Total hip arthroplasty (THA) is one of the most common surgical procedures in orthopedics; however, it is subjected to different kinds of failures, one of them being dislocation. Many different prosthetic designs have been developed to overcome this problem, such as dual mobility coupling. The main purpose of this article is to determine whether there are differences regarding the revision surgery of unstable THA comparing the risk of failure between dual mobility cup (DMC) implants, standard implants, and among different head sizes. A registry-based population study has been conducted by analyzing data collected by the Emilia Romagna Registry of Orthopedic Prosthetic Implants (RIPO), including a total of 253 implants failed for dislocation and instability that were operated on by cup revision surgery between 2000 and 2019. The selected population has been divided into two groups based on the insert type: standard and DMC. The age at revision surgery was significantly lower in the standard cup group with respect to DMC (p = 0.014 t-test), with an average age of 71.2 years (33-96 years range) for the standard cups and 74.8 years (48-92 years range) for the DMC group. The cumulative survival of DMC implants was 82.0% at 5-years, decreasing to 77.5% at a 10-year follow-up, which is not significantly different from standard cups (p = 0.676, Log-Rank test). DMC implants showed a significantly lower risk of re-revision for dislocation compared to standard cups (p = 0.049). Femoral heads ≥36 mm had a higher overall survival compared to smaller femoral heads (p = 0.030). This study demonstrated that DMC or femoral heads ≥36 mm are a valid choice to manage THA instability and to reduce the revision rate for dislocation at a mid-term follow-up; in those selected and targeted patients, these options should be taken into consideration because they are associated with better outcomes.

Does Matching Femoral Size and Shape Improve Bone Fit and Patient-reported Outcomes in TKA? A Matched Controlled Study.

Some researchers have suggested that achieving good component coverage over the host bone during TKA (while avoiding implant overhang) may help achieve durable implant fixation and may be associated with better outcomes scores. However, the evidence about this is limited and contradictory. Contemporary morphometric TKA includes a wide array of components with various shapes and sizes, based on large anatomic databases and specific software that simulates bone cuts. Morphometric tibial components have shown improved bone coverage and better clinical outcomes than standardized implants, but the role of morphometric femoral components in bone coverage has not been studied precisely. In a retrospective, controlled study that used patient matching, we asked: (1) Does the use of a contemporary morphometric component with more available sizes provide better femoral component fit and bone coverage than an earlier design with fewer sizes? (2) Are component fit and the presence of component overhang or underhang associated with different Knee Society Score (KSS) or Knee Injury and Osteoarthritis Outcome Score (KOOS) for Joint Replacement? From 2012 to 2013, we performed 403 TKAs according to the following criteria: TKA performed for primary tricompartmental arthritis of the knee; varus, valgus, and flexion deformity less than 15°; and age between 18 and 85 years on the day of surgery. Among these 403 TKAs, 237 were performed using a morphometric implant and 166 with the earlier nonmorphometric implant. At 2 years of follow-up, 3% of patients in the morphometric group and 5% in the nonmorphometric group were lost to follow-up. Based on age, BMI, gender, and preoperative KSS and KOOS, two groups of 30 patients were matched in a 1:1 ratio from this longitudinally maintained database. Clinical outcomes were measured preoperatively and at a minimum follow-up of 2 years in both groups, using the KSS and KOOS. We evaluated postoperative CT images for each patient to analyze femoral implant rotation, bone coverage, and overhang and underhang status. The overhang status was similar between the two groups (23% had an overhang component in the morphometric knee group and 27% had an overhang component in the nonmorphometric knee group), and overhang was most frequently found in the lateral distal zone and medial anterior chamfer. Better cortical bone coverage was found in the morphometric knee group, with a thinner bone margin between the component edge and cortical border (morphometric group: 3 mm versus nonmorphometric knee group: 5 mm; p = 0.01). In general, there were few between-group differences in terms of patient-reported outcomes; of the seven metrics we analyzed, only the KSS favored the morphometric knee implant by a margin larger than the minimum clinically important difference (KSS mean difference: 21 points for the morphometric knee group; p < 0.05). Overhang of the femoral component of > 2 mm was associated with poorer KOOS, but not KSS, whereas a thinner bone margin had a beneficial impact on pain and global clinical scores (KOOS and KSS: p < 0.05). The use of a morphometric femoral component design showed slightly improved bone fit and pain score according to the KSS at midterm follow-up compared with earlier implants with fewer sizes. Overhang > 2 mm was associated with worse KOOS. The tendency toward better outcomes in morphometric implants warrants longer-term evaluation before any definite conclusions about the association between bone fit and clinical results can be drawn.Level of Evidence Level III, therapeutic study.

The versatile and minimally invasive mini and narrow diameter implants: A case series

ABSTRACT The awareness and demand for implants as a treatment option have put the onus on the dentist to adapt to the patient’s requirements. Standard diameter implants cannot be placed in all situations due to limited bone volume, altered systemic status of patients, or financial constraints. Mini and narrow-diameter implants may be a reliable alternative in such circumstances. They have demonstrated good success and survival rates for the replacement of maxillary lateral incisor, mandibular anterior teeth, maxillary or mandibular posterior teeth when the occlusal load is favorable, and maxillary or mandibular overdentures. Splinting these mini implants has been shown to decrease the stresses on the bone and improve the load-bearing capacity. The three cases described here validate the usefulness of mini implants where standard diameter implants were not feasible.

Distance and intermediate visual acuity after a new generation monofocal intraocular lens compared with the standard monofocal intraocular lens implantation

Purpose The aim of this study was to determine the effectiveness of a novel innovative monofocal intraocular lens (Tecnis Eyhance ICB00) compared with the standard monofocal lens (Tecnis-1-piece ZCB00) in terms of contrast sensitivity, postoperative refraction, intermediate visual acuity (VA), and uncorrected and best-corrected distance VA. Patients and methods This prospective comparative interventional clinical study was conducted from January 2021 to November 2021. It included 40 eyes of 20 patients who were divided into two groups, with 10 patients each. Candidates for bilateral cataract extraction by phacoemulsification were included in this study and underwent thorough preoperative examination and postoperative evaluation at 3 months after the second eye operation. The outcome measures included intermediate and distance VA, near add, contrast sensitivity, and incidence of photic phenomena, which was evaluated using a printed questionnaire. The binocular defocus curves were analyzed. Results The study included 20 patients (seven males and 13 females). Binocular and monocular uncorrected and corrected distance VAs were statistically similar in both groups. The Eyhance group demonstrated significantly higher binocular uncorrected and corrected intermediate VA compared with the TECNIS 1-piece group (P<0.001). Defocus and contrast sensitivity values were not significantly different between the two groups. Conclusion Patients who were bilaterally implanted with the new monofocal intraocular lenses achieved significantly higher intermediate VA outcomes without affection of distance VA, with similar mean contrast sensitivity values and low incidence of photic phenomena like halo and glare compared with the standard monofocal lens.

Influence of implant design and length on stress distribution in immediately loaded implants in posterior maxilla - A two-dimensional finite element analysis.

The aim of this two dimensional (2D) finite element analysis study was to evaluate the influence of implant design (step and tapered) and length on stress distribution at bone implant interface, when placed in maxillary posterior bone under immediate loading protocol. 2D finite element models were developed to simulate the two types of implant designs, i.e., Tapered and step implants of 3.75-mm - Diameter and 6 and 10 mm lengths, respectively. Maxillary posterior bone quality (D4 bone) was simulated with a very thin cortical bone (0.5 mm) for the placement of implants. The respective material properties were assigned. The implant designs incorporated microthreads at the crestal part and rest of the implant body incorporated Acme threads. Forces of 100 Newtons were applied vertically and in oblique direction (at an angle of 45°) to long axis of the implants. Total deformation (micromovements), stresses and strains were evaluated at the bone implant interface. The results of micromovements, stresses and strains were found to be lower for long implants as compared to short implants. Also, all the values were found to be higher for oblique loads as compared to vertical loads. The von mises stress values were highest for 6 mm step implants and lowest for 10 mm step implants. In the presence of low bone density with optimal bone height, standard diameter long step implants can be used. Incorporation of microthreads at the crestal portion and acme threads for body portion of the implant presents a good option to be used under immediate loading protocol.

Effect of implant diameter and cantilever length on the marginal bone height changes and stability of implants supporting screw retained prostheses: A randomized double blinded control trial.

This randomized controlled trial aimed to evaluate the effect of implants' two different diameters and cantilever lengths on the marginal bone loss and stability of mplants supporting maxillary prostheses. Ninety-six implants were placed in sixteen completely edentulous maxillary ridges. Patients were randomly divided into two groups: Group A, implants were placed with a cantilever to anterior-posterior AP spread length (CL:AP) at a ratio of 1:3; Group B, implants were placed with a CL:AP at a ratio of 1:2. Patients were further divided into four sub-groups: Groups A1, A2, B1, and B2. Groups A1 and B1 received small diameter implants while Groups A2 and B2 received standard diameter implants. Bone height and stability measurements around each implant were performed at 0, 4, 8 and 24 months after definitive prostheses delivery. Statistical analysis of the mean implant stability and height values revealed an insignificant difference between Group A1 and Group A2 at all the different time intervals while significantly higher values in Group B1 in comparison with Group B2. Results also showed significantly higher values in Group A1 in comparison with Group B1 and an insignificant difference between Group A2 and Group B2 at all the different time intervals. It can be concluded that the use of small diameter implants placed with a CL:AP at a ratio of 1:3 provided predictable results and that the 1:2 CL:AP significantly induced more critical bone loss in the small diameter implants group, which can significantly reduce long term success and survival of implants.

Clinical Evaluation of Short (6 mm) and Longer Implants Placed Side by Side in Posterior Partially Edentulous Area: A 3-Year Observational Study.

Short implants have been proposed as an alternative solution for the rehabilitation of atrophic posterior region. To compare the clinical outcomes between 6 mm short implants and conventional implants placed under similar conditions of bone quality and occlusal loading. Nine patients received atone 6 mm implant and one standard-length (8 mm length or longer) implants in a total of 10 partially edentulous areas. Implants were left submerged for 3-6 months healing period and the screw-retained splinted prostheses were delivered. When the provisional or final restoration was placed, and at each year after loading, standardized intraoral radiograph was taken for themarginal bone level (MBL) changes around the implants. Subsequently, the patients were recalled for the clinical examination evaluating the implant survival, sulcus bleeding index, suppuration, and the incidence of prosthetic complications at every 6 months after the definitive crown delivery. The observation period was continued to 3 years (mean follow-up was 3.4 ± 0.3 years) after functional loading. Nine patients (10 short implants and 10 standard length implants) were selected in this study. Cumulative survival rates of the short implants and standard-length implants were 100% in both groups, and no biological and prosthetic complication were found in 3 years observation period. Cortical bone thickness of implant insertion sites was 1.39 ± 0.45 mm at short implants and 1.38 ± 0.69 mm at standard-length implants, and trabecular bone computed tomography values of implant insertion sites was 424.1 ± 290.1 at short implants and 410.9 ± 267.9 at standard-length implants. The MBL changes were -0.30 ± 0.71 mm at short implants and -0.19 ± 0.78 mm at standard-length implants at 3 years follow-up visit. No significant difference was found in the average of MBL changes between implant length. Within the limits of this study, it can be concluded that 6 mm short implants in a posterior edentulous region showed excellent results compared with conventional implants.

Navigation in oral surgery: a systematic review

Introduction: Dynamic navigation is a fast-growing technology in the field of head and neck surgery, which is now taking its place in oral surgery. The aim of this review was to present and describe all the uses of navigation in oral surgery. Materials and methods: A systematic review was conducted using all clinical trial/cases reports (Embase/PubMed) in which navigation is used during oral surgery, published over the last 5 yr. A total of 32 clinical trial/cases reports were analyzed. Results: Dynamic navigation was used in 7 different indications: implantology (55%), foreign body removal (15%), dental avulsion (12%), bone augmentation (9%), cellulitis (3%), benign tumour (3%), pre-prosthetic surgery (3%). A total of 335 patients were treated, 631 implants, 8 foreign bodies, 1 benign tumour, 24 dental avulsions, 3 bone augmentations, 1 cellulitis, and 1 pre-prosthetic surgery were found. In implantology, there were 500 standard implants, 75 zygomatic implants, 31 pterygoid implants, 1 short implant and 24 angulated implants. Conclusion: This review showed the recent development of dynamic navigation in oral surgery. The most common indication is dental implantology and few others indications seemed promising. This technique broadened its scope and might become an indispensable tool that can be used in many situations, increasing safety and predictability of a lot of procedure.

A Novel Design to Optimize Biomechanical Properties of Dental Implant

Objective: The main objective of this study is to evaluate a novel design to optimize dental implant biomechanics. According to this objective, evaluations of the resilient implant design which aimed to mimic biomechanical behaviors of natural tooth have been made and outcomes were compared with natural tooth and standard dental implants with using 3D hyper-elastic finite element analysis. Methods: Models used in the study corresponding to conventional dental implant, natural tooth and resilient dental implant design. Hyperelastic model analysis were performed for close presentment of mechanical behaviors of resilient materials like periodontal ligament and medical silicone. Top values of maximum principal stress, minimum principal stress of surrounding bone and displacement of each model were evaluated under axial and non-axial loading conditions with magnitude of 30N, 80N and 100N. Results: Outcomes of finite element study showed reduction on maximum principal stress and minimum principal stress levels with the use of resilient dental implant comparing to the standard implant model. Standard implant model had been observed notably rigid in all loading conditions compared to the other models. Resilient implant model showed similar biomechanical characteristics with natural tooth model within the limitations of this study. Conclusion: According to finite element analysis results; resilient implant design was able to resolve some biomechanical discrepancies and seem to have adequate biomechanical similarity with natural tooth under both axial and non-axial loading conditions.

Retrospective cohort assessment of survival and complications of zygomatic implants in atrophic maxillae.

To report on zygomatic implant (ZI) survival rate and associated complications through a longitudinal retrospective cohort assessment. A total of 940 ZIs (rough: 781, machined: 159; immediate loading: 454, delayed loading: 486) and 451 standard implants (rough: 195, machined: 256; immediate loading: 58, delayed loading: 393) were placed in 302 adult patients with atrophic maxilla from December 1998 till September 2020. Following data collection reported complications were grouped based on their origin as infectious/ non-infectious biological and mechanical. Statistical analysis was performed to identify risk factors and preceding complications leading to implant loss (P < 0.05). The survival rate of ZI was found to be 89.9% and the average time between implant placement and an eventual loss was 4.8 years. The mean ZI follow-up period was 7.9 ± 4.9 years. Amongst the infectious biological complications, sinusitis was the most reported (n=138) occurring at a mean follow-up time-point of 4.5 years, whereas infraorbital nerve hypoesthesia occurred more frequently in the non-infectious biological category (n=8, meantime: 0.3 years). The prosthetic screw fracture was the most reported complication of mechanical origin (n=29, meantime: 4 years). Furthermore, sinusitis, standard implant loss, zygomatic/peri-zygomatic region infection, and oroantral communication were significantly associated with ZI loss. ZI placement offered a high survival rate for the rehabilitation of severely atrophied maxilla with most losses occurring within the first 5 years at follow-up. The most frequently observed complication was sinusitis which tends to develop several years following implant placement.

Insertion Torque, Removal Torque, and Resonance Frequency Analysis Values of Ultrashort, Short, and Standard Dental Implants: An In Vitro Study on Polyurethane Foam Sheets.

Short implants were introduced to reduce morbidity, treatment duration, and complex bone regeneration interventions in atrophic jaws and to improve patient-reported outcomes. This study aimed to determine the insertion torque (IT), removal torque (RT), and resonance frequency analysis (RFA) values of ultrashort (3 mm length), short (7 mm length), and standard implants (10 mm length) inserted in 1-, 2-, 3-, and 4-mm thickness polyurethane sheets with densities of 10, 20, and 30 pounds per cubic foot (PCF). Standard-length implants were the gold standard (control). Overall, short-length implant IT values were higher or similar to the control in most experimental conditions. Those inserted into a 3 mm/30 PCF lamina showed the highest IT values, whereas 5 mm diameter ultrashort-length implants inserted into 2 and 3 mm/20 PCF laminas were higher than other implants. RT values followed the same trend and RFA values were more appreciable in short- and standard-length implants in all the scenarios. However, ultrashort-length implants reached a primary stability comparable to that of standard implants in lower thicknesses. In conclusion, although further studies are needed to corroborate this in vitro model with preclinical and clinical studies, our data shed light on short- and ultrashort-length implants geometries to a potential application in critical atrophy of the posterior jaws.

Clinical Outcome of Immediate Loading UV-Photofunctionalized Implants in Patients with Completely Edentulous Mandible, Placed with Guided Surgery.

The purpose of this study was to evaluate clinical results of immediate loading UV-photofunctionalized dental implants placed using guided surgery in patients with completely edentulous mandible. In this study, 58 fully edentulous patients were treated with immediate loading implant-supported mandibular prostheses. All patients underwent a thorough clinical examination according to the generally accepted scheme; qualitative and quantitative parameters of the jaw bones patients were diagnosed with cone beam computerized tomography (CBCT). Surgical templates modeled in the 3 Shape software were made from biocompatible polymeric materials and provided with depth-calibrated drill sleeves for preparing osteotomies using a 3D printer (Stratasys). Before short implant placement, ultraviolet functionalization of implant surfaces was performed by UV Activator YWJ-QSY001 (Foshan, Wenjian Medikal Enstriman) in the device for 20s. After flapless surgery, implant sockets were prepared with guided surgery and implants were placed through the sleeves of the surgical template tightening torque of 35-45 Ncm. An implant-supported temporary prosthesis made of acrylic resin was installed 6h after implantation. Final dental prosthetics was performed 2months after implant placement.The patients had 128 short (length 5-6mm, diameters 4,5-5mm) and 256 implants with length greater than 10mm in bone segments with sufficient bone parameters. The following parameters were assessed: implant success, prosthetics survival and changes in peri-implant marginal bone loss(MBL). During a clinical examination, no serious biological or prosthetic complications have been reported. The esthetic result evaluated from patients was excellent. The mean ISQ of short implants was 69.2 ± 8 for primary stability at implant placement and 73.6 ± 4 ISQ after 3months. The mean of implants with length greater than 10mm was 71,2ISQ at implant placement, respectively, and 75,6 ISQ after 3months. After 3months of prosthetic loading for short implants marginal bone loss (MBL) 0.74mm, after 1year of MBL 11.21mm, after 5years of MBL 1,37mm, for implants with length greater than 10mm after 3months of MBL 0.72mm, after 1year of MBL 1.19mm and after 5years of MBL 1.35. There was no statistically significant difference in clinical indices between short and standard implants. After 5years of follow-up, stable levels of bone tissue around the implants and healthy tissues around the implants were recorded, and postoperative occlusal function was favorable. The success rates of the short implants in maxilla were 95.5%, and the success rates of the short implants in mandible were 98.7%. The success rates of the implants with length greater than 10mm in maxilla were 97.8%, and the success rates of the implants with length greater than 10mm in mandible were 98.8%. Computer-guided implant surgery and immediate loading of UV-photofunctionalized implants in patients with completely edentulous mandible are a predictable and effective method with a minimum rehabilitation period.

Improvement of mechanical properties of oak-wood by bi-directional laminations – Efficacy of standard and pre-stressed glass fibre implants

This paper brings results of the bending testing of oak-wood laminated elements for structural use. The bi-directional laminations were reinforced with six types of implants made of glass fibre reinforced polymer (GFRP), some of which were pre-stressed before embedding in epoxy resin. Previously we reported on improving the mechanical properties of oak-wood laminated elements using carbon fibre implants (CFRP). Although it proved as an efficient improvement of the mechanical properties, it also raised the question of the cost effect to the final product. Therefore, within the larger study on investigating effects of different reinforcement systems, we tested glass fibres reinforced polymer (GFRP) as an alternative. Results showed that the introduction of implants improved the effective stiffness between 4 and 51 % and the ultimate load to failure up to 55 %. Furthermore, not only that insertion of the GFRP layers significantly contributed to the strength and stiffness improvement, but the ductility of the elements increased up to 32 %. Pre-stressing of the glass fibres reinforced polymer implants in tension before their installation contributed to the strength increase to a much greater extent than the increase in the number of layers. The best reinforcement effect is obtained if two layers of pre-stressed GFRP are used.

Investigation of Topographical Alterations in Titanium-Zirconium-Alloy Implant Threads following Er:YAG Irradiation.

The aim of the current experimental study was to comparatively assess the surface alterations in titanium and titanium-zirconium alloy implants in terms of thread pitch topography after irradiation with an Er:YAG laser, which is recommended in the literature for its sterilizing effect in the treatment of contaminated implant surfaces. Roxolid® and SLA® (Sand-blasted, Large-grit, Acid-etched) implants from Straumann® company with the same macro topography were investigated. The surface treatment was carried out using a wavelength of 2940 nm, 60 s irradiation time, a frequency of 10 Hz, and energies between 120 mJ and 250 mJ. The alterations were quantitatively analyzed by conducting roughness analysis via white light interferometry and qualitatively using SEM images. Roxolid® could particularly maintain its surface topography at a level of 160 mJ. At an energy level of 250 mJ, the surface properties of the pitch could be significantly altered for the first time. Compared to the Standard Plus dental implants studied, no distinct removal of the material from the surface was detected. The alloy properties of Roxolid® confirm the manufacturer's statement in terms of stability and could offer advantages in peri-implantitis management if decontamination has been selected. However, as a part of a respective strategy, smoothening of a Roxolid® implant surface requires a significantly higher energy level compared to SLA-Standard® dental implants.

Biomechanical studies of different numbers and positions of cage implantation on minimally invasive transforaminal interbody fusion: A finite element analysis.

The position and number of cages in minimally invasive transforaminal interbody fusion (MIS-TLIF) are mainly determined by surgeons based on their individual experience. Therefore, it is important to investigate the optimal number and position of cages in MIS-TLIF. The lumbar model was created based on a 24-year-old volunteer's computed tomography data and then tested using three different cage implantation methods: single transverse cage implantation (model A), single oblique 45° cage implantation (model B), and double vertical cage implantation (model C). A preload of 500 N and a moment of 10 Nm were applied to the models to simulate lumbar motion, and the models' range of motion (ROM), ROM ratio, peak stress of the internal fixation system, and cage were assessed. The ROM ratios of models A, B, and C were significantly reduced by >71% compared with the intact model under all motions. Although there were subtle differences in the ROM ratio for models A, B, and C, the trends were similar. The peak stress of the internal fixation system appeared in model B of 136.05 MPa (right lateral bending), which was 2.07 times that of model A and 1.62 times that of model C under the same condition. Model C had the lowest cage stress, which was superior to that of the single-cage model. In MIS-TLIF, single long-cage transversal implantation is a promising standard implantation method, and double short-cage implantation is recommended for patients with severe osteoporosis.

Comparison of Clinical and Economic Outcomes of an Optimized Lean Versus a Standard Transcatheter Aortic Valve Implantation Program (from SOLAR [Safe Outcomes Lean And Resourceful] Study)

The increasing prevalence of aortic stenosis (AS) and the increasing number of patients indicated for transcatheter aortic valve implantation (TAVI) can lead to increased hospital constraints. This study aimed to compare, from the hospital perspective, the costs, resource use, and 30-day clinical outcomes of patients who underwent TAVI under an optimized or standard clinical pathway. A single-center, retrospective study was conducted among patients with native AS who underwent TAVI between January 2018 and March 2021. Patients who underwent optimized lean TAVI were propensity-score matched 1:1 to those who underwent standard TAVI. In-hospital costs and 30-day clinical outcomes were compared between the 2 groups. A total of 182 patients (91 in each group) were included in the final analysis. Baseline covariates were well balanced after matching. Patients who underwent lean TAVI had shorter length of stay (median [interquartile range] 3.0 days [2.0 to 6.0] vs 6.0 days [5.0 to 9.0], p <0.001). Patients in the lean TAVI group incurred lower total costs than did those in the standard TAVI group (mean ± SD: $41,346 ± 10,062 vs $50,471 ± 15,115, p=0.002). There was no between-group difference in 30-day all-cause mortality (2.2% vs 1.1%, p=0.573) and pacemaker implantations (5.5% vs 6.6%, p=0.788). Rates of procedural complications were comparable between groups. In conclusion, lean TAVI leads to hospital efficiencies without compromising patient safety. Efforts to streamline the TAVI procedure should be encouraged to improve access to TAVI for patients with AS, amid resource constraints.