Implant Length Research Articles

Pediatric vagal nerve stimulator explantation: A comprehensive literature review and tertiary care experience.

Patients with medically-refractory epilepsy who undergo vagal nerve stimulator (VNS) implantation to reduce seizure burden sometimes require device removal. Complete explantation refers to the removal of both the generator and vagal nerve leads, and is uncommonly performed by otolaryngologists due to the perceived risk associated with lead removal. This comprehensive literature review and case series studies safety outcomes among pediatric patients undergoing complete VNS explantation. Literature review and tertiary care case series. PubMed, Embase, Web of Science, and Google Scholar were searched to identify all articles involving VNS explantation prior to January 2023. A retrospective review of pediatric patients undergoing complete VNS explantation from 2009 to 2023at our tertiary center was also conducted. After screening, 36 articles were retained involving 399 patients (139 confirmed children) who underwent complete VNS explantation. 26 patients (6.5%) experienced 1+ peri/post-operative complications. These included temporary VF paresis or dysphonia (n=14; 3.6%), permanent vocal fold (VF) paralysis/paresis (n=6; 1.5%), internal jugular vein injury (n=4; 1.0%), temporary dysphagia (n=2; 0.50%), and cable-bowstring phenomenon (n=1; 0.25%). Data from our tertiary care center revealed eight patients (6M: 2F) with a mean age of 11.4±6.2 years. Devices were removed for clinical ineffectiveness (n=2), infection (n=2), lead failures (n=2), and increased lead impedance (n=2). Mean total length of implantation was 44.4±40.3 months. Mean follow-up was 44.8±35.2 months. No complications were identified. Complete VNS device removal in pediatric patients is technically feasible with low reported complications. Working alongside neurosurgery, otolaryngologists offer unique expertise in dissection along the vagus nerve and may thus add value to the practice of VNS surgery.

Immediate loading full-arch rehabilitation using transmucosal tissue-level implants with different variables associated: a one-year observational study.

The aim of the present observational study was to investigate the application of transmucosal tissue-level implants in immediate loading full-arch rehabilitation with different variables associated. Patients needing a full-arch implant rehabilitation were recruited and rehabilitated with four transmucosal tissue level implants. Data related to implants' diameters and lengths, jaw distributions, and presence of angulated abutments were collected. The following outcomes were evaluated: survival rate, marginal bone loss (MBL), Plaque Index (PI), bleeding on probing (BoP), probing depth (PD). Descriptive statistical analysis was reported and univariate linear regression models were built to assess a significant correlation between MBL and the different implant related factors. Twenty patients were rehabilitated for a total implant number of 80; 11 rehabilitations were performed on the maxilla, while 9 were performed on the mandible; 48 implants presented a 3.8 mm diameter and 32 implants presented a 4.25 mm diameter. Implants length varied between 10 to 15 mm; 40 tilted implants were connected to angulated abutment, while 40 straight implants were connected directly to the prostheses (no abutments). At the one year follow-up visit no implants failed resulting in an implant survival rate of 100%. The overall MBL was 1.19±0.30 mm. No statistically significant difference (P>0.05) was highlighted among any of the subgroups analyzed. Despite different variables associated, tissue level implants seem to represent a valid option when applied in immediate loading full-arch rehabilitation. Further research and longer observational periods are encouraged to confirm the result.

Development and evaluation of cardiac implantable electronic devices knowledge scale.

Patients with cardiac implantable electronic devices (CIEDs) need specific education to successfully adapt to life with new devices in their bodies. This requires specifically-tailored training processes. To determine the educational requirements, robust measurement tools are essential; however, a literature review revealed that no reliable and valid knowledge scale currently exists for patients with CIEDs. The study was conducted to develop and test the psychometric properties of the scale for measuring the knowledge of patients with CIEDs. The cross-sectional and descriptive study was conducted with 150 patients with CIEDs. Data were collected with a specially-developed cardiac implantable electronic devices knowledge (CIEDsK) Scale consisting of 14 questions. To determine the reliability of the scale, the following tests were performed: Kuder Richardson-20 reliability coefficient, intraclass correlation (ICC) analysis, and corrected item-total scale correlation analyses. The content validity, predictive validity, and item discrimination index were examined to evaluate the validity of the scale. The Kuder Richardson-20 reliability coefficient indicated very good internal consistency (.92). ICC was .92, demonstrating excellent reliability. Four questions were removed after failing to meet the inclusion criteria for the content validity index (<0.70), the discrimination index (<0.10), and item-total correlation (<0.20). Predictive validity analyses showed that the following were effective in predicting the total score: age, income status, implantation length, and informed by a healthcare professional, however, education level was not. After all analyses, 10 multiple-choice questions remained in the final scale about living with CIEDs. The study showed that the CIEDsK scale is valid and reliable for measuring the knowledge of patients with CIEDs in daily practice. Thus, patient-tailored education sessions can be designed according to the knowledge level of the patients determined.

Consequences and Predictors of Prolonged Tissue Expander Duration in Breast Reconstruction.

Tissue expanders (TEs) are temporary devices used in breast reconstruction, which are generally removed within 1 year. There is a paucity of data regarding the potential consequences when TEs have longer indwelling times. Thus, we aim to determine whether prolonged TE implantation length is associated with TE-related complications. This is a single-center retrospective review of patients who underwent TE placement for breast reconstruction from 2015 to 2021. Complications were compared between patients who had a TE for >1 year and <1 year. Univariate and multivariate regressions were used to evaluate predictors of TE complications. A total of 582 patients underwent TE placement and 12.2% had the expander for >1 year. Adjuvant chemoradiation, body mass index (BMI), overall stage, and diabetes predicted the duration of TE placement (p ≤ 0.006). Rate of return to the operating room was higher in patients who had TEs in place >1 year (22.5 vs 6.1%, p < 0.001). On multivariate regression, prolonged TE duration predicted an infection requiring antibiotics, readmission, and reoperation (p < 0.001). Reasons for longer indwelling times included need for additional chemoradiation (79.4%), TE infections (12.7%), and requesting a break from surgery (6.3%). Indwelling TEs for >1 year are associated with higher rates of infection, readmission, and reoperation even when controlling for adjuvant chemoradiation. Patients with diabetes, a higher BMI, advanced cancer stage, and those requiring adjuvant chemoradiation should be advised they may require a TE for a longer time interval prior to final reconstruction.

Virtual pterygoid implant planning in maxillary atrophic patients: prosthetic-driven planning and evaluation

PurposeThe study aims to use cone beam computed tomography (CBCT) to (1) define the virtual valid length of pterygoid implants in maxillary atrophic patients from the prosthetic prioritized driven position and (2) measure the implant length engaged in the pterygoid process according to the HU difference of the pterygoid maxillary junction.Materials and methodsVirtual pterygoid implants were planned with CBCT of maxillary atrophic patients in the software. The entry and angulation of the implant were planned according to the prosthetic prioritized driven position in the 3D reconstruction image. The planned implant length and the valid length defined as the implant between the pterygoid maxillary junction and pterygoid fossa were recorded. The relationship between the implant and sinus cavity was also evaluated.ResultsA total of 120 CBCT samples were enrolled and virtually planned. The mean age of the patients was 56.2 ± 13.2 years. One hundred and sixteen samples could successfully place virtual implants according to the criterion. The mean implant length and mean implant length beyond the pterygoid maxillary junction were 16.3 ± 4.2 mm (range, 11.5–18 mm) and 7.1 ± 3.3 mm (range, 1.5–11.4 mm), respectively. Ninety percent of virtually planned implants had a close relationship with the sinus cavity, and implants exhibited longer lengths when they had no relation with the sinus.ConclusionFrom a prosthetic prioritized driven position with fixed entry and angulation, pterygoid implants achieve adequate bone anchorage length beyond the pterygoid maxillary junction. Due to the individual anatomy and the volume of the maxillary sinus, the implants presented a different positional relationship with the maxillary sinus.Graphical

Biomechanical influence of narrow-diameter implants placed at the crestal and subcrestal level in the maxillary anterior region. A 3D finite element analysis.

To evaluate the tendency of movement, stress distribution, and microstrain of single-unit crowns in simulated cortical and trabecular bone, implants, and prosthetic components of narrow-diameter implants with different lengths placed at the crestal and subcrestal levels in the maxillary anterior region using 3D finite element analysis (FEA). Six 3D models were simulated using Invesalius 3.0, Rhinoceros 4.0, and SolidWorks software. Each model simulated the right anterior maxillary region including a Morse taper implant of Ø2.9mm with different lengths (7, 10, and 13mm) placed at the crestal and subcrestal level and supporting a cement-retained monolithic single crown in the area of tooth 12. The FEA was performed using ANSYS 19.2. The simulated applied force was 178N at 0°, 30°, and 60°. The results were analyzed using maps of displacement, von Mises (vM) stress, maximum principal stress, and microstrain. Models with implants at the subcrestal level showed greater displacement. vM stress increased in the implant and prosthetic components when implants were placed at the subcrestal level compared with the crestal level; the length of the implants had a low influence on the stress distribution. Higher stress and strain concentrations were observed in the cortical bone of the subcrestal placement, independent of implant length. Non-axial loading influenced the increased stress and strain in all the evaluated structures. Narrow-diameter implants positioned at the crestal level showed a more favorable biomechanical behavior for simulated cortical bone, implants, and prosthetic components. Implant length had a smaller influence on stress or strain distribution than the other variables.

Consequences and Predictors of Prolonged Tissue Expander Duration in Breast Reconstruction

Introduction: Tissue expanders (TEs) are temporary devices used in breast reconstruction, which are generally removed within one year. There is a paucity of data regarding the potential consequences when TE’s have longer indwelling times. Thus, we aim to determine whether prolonged TE implantation length is associated with TE-related complications. Materials and Methods: This is a single center retrospective review of patients who underwent tissue expander placement for breast reconstruction from 2015-2021. Complications were compared between patients who had a TE for > 1 year and < 1 year. Univariate and multivariate regressions were used to evaluate predictors of TE complications. Result: A total of 582 patients underwent TE placement and 12.2% had the expander for > 1 year. Adjuvant chemoradiation, BMI, overall stage, and diabetes predicted the duration of TE placement (p ≤ 0.006). Return to the OR rate was higher in patients who had TEs in place > 1 year (22.5% vs 6.1%, p < 0.001). On multivariate regression, prolonged TE duration was the only factor that predicted an infection requiring antibiotics, readmission, and re-operation (p < 0.001). Reasons for longer indwelling times included need for additional chemoradiation (79.4%), TE infections (12.7%), and requesting a break from surgery (6.3%). Conclusion: Indwelling TEs for > 1 year are associated with higher rates of infection, readmission, and re-operation even when controlling for adjuvant chemoradiation. Patients with diabetes, a higher BMI, advanced cancer stage, and those requiring adjuvant chemoradiation should be advised they may require a TE for a longer time-interval prior to final reconstruction.

Clinical and Biomechanical Characteristics of Posterior-Stabilized Polyethylene Post Fractures in Total Knee Arthroplasty: A Retrieval Analysis

BackgroundFractures of the polyethylene post are a rare but known complication after posterior-stabilized (PS) total knee arthroplasty (TKA). We evaluated the polyethylene and patient characteristics for 33 primary PS polyethylene components that were revised with fractured posts. MethodsWe identified 33 PS inserts revised between 2015 and 2022. Patient characteristics collected included age at index TKA, sex, body mass index, length of implantation (LOI), and patient-reported details on events surrounding the post fracture. Implant characteristics recorded were manufacturer, cross-linking properties (highly cross-linked polyethylene [XLPE] versus ultra-high molecular weight polyethylene [UHMWPE]), wear characteristics based on subjective scoring of the articular surfaces and scanning electron microscopy (SEM) of fracture surfaces. Mean age at index surgery was 55 years (range, 35 to 69), mean body mass index was 29.5 (range, 18.5 to 37.2), and mean LOI was 10.0 (range, 4 to 26). ResultsTotal surface damage scores were significantly higher in the UHMWPE group versus the XLPE group (57.3 versus 44.2, P = .003). SEM demonstrated fracture initiation at the posterior edge of the post in 10 of 13 cases. UHMWPE fracture surfaces posts had more tufted, irregularly clamshell features, while XLPE posts had more precise clamshell marking and a diamond pattern in the region of acute, final fracture. ConclusionCharacteristics of PS post fracture differed between XLPE and UHMWPE implants, with fractures occurring in the XLPE with less generalized surface damage, after a shorter LOI, and with SEM evaluation indicative of a more brittle fracture pattern.

Meniscus Work and Implant Selection Are Major Cost Drivers of Anterior Cruciate Ligament Reconstruction.

Background The current study examines the financial charges associated with primary anteriorcruciate ligament reconstruction (ACLR), specifically the contribution of graft choice, graft type, and concomitant meniscus surgery, in the outpatient hospital setting. Methods A retrospective financial billing review was performed on patients who underwent ACLR at a singleacademic medical center from January to December 2019. Age, BMI, insurance, length of operation, regional block, implants, meniscus surgery, graft type, and graft choice were extracted from hospital electronic patient records. Charges attributed with graft, anesthesia services, supplies, implants, surgeon fees, radiology charges, and total charges were collected. Total amount that insurance and patient paid were also obtained. Descriptive and quantitative statistics were performed. Results A total of 28 patients were studied (18 males, 10 females). The average age was 23.8 years. There were 20 concomitant meniscus surgeries. Six allografts and 22 autografts were used [eight bone-patellar tendon-bone (BPTB), eight hamstrings, six quadriceps]. The average and median total charge was $61,004 and $60,390, respectively (range: $31,403 to $97,914). The average insurance paid was $26,045 while out-of-pocket costs were $402. The average paid by privateinsurance was higher compared to government insurance($31,111 vs. $11,066, p<0.001). Graft choicesuch as allograft vs. autograft (p=0.035) and meniscus surgery (p=0.048) were significant factors to the overall cost. Conclusions Graft choice, specifically the quadrupled hamstring autograft, and concomitant meniscal surgery are major contributors to variations in ACLR charges. Decreasing implant and graft costs and limiting surgical time can decrease charges associated with ACLR.We hope these findings can help guide surgeon financial decisions, by demonstrating the need to take into account the increased total charges and amount paid associated with specific grafts, meniscus surgery, and prolonged OR time.

Effect of Implant Length and Insertion Depth on Primary Stability of Short Dental Implant

Purpose: To evaluate the effect of insertion depth, bone type, and implant diameter on the primary stability of short implants. Materials and Methods: Commercial dental implants with different lengths (6 and 8 mm; BLX, Straumann) were inserted into artificial bone specimens of good and poor quality at three different depth positions: equicrestal, 1-mm subcrestal, and 2-mm subcrestal. Insertion torque values were recorded spontaneously during the implant procedure. Both maximum insertion torque values (MITVs) and final insertion torque values (FITVs) were recorded. Subsequently, Periotest values (PTVs) and implant stability quotients (ISQs) were measured for all specimens. Results: The mean MITVs of all groups ranged from 31.8 to 46.2 Ncm. However, the mean FITVs of all groups ranged from 8.8 to 29 Ncm. Torque values decreased significantly when the implants were inserted into their final positions. When insertion depth was increased, the PTV and ISQ decreased. Long implants and implants inserted into good-quality bone yielded greater primary stability, and bone quality appeared to have a greater effect on primary stability. Conclusion: When 6-mm short implants are inserted in a subcrestal position, low primary stability may be yielded, particularly in poor-quality bone.

Evaluation of Stress and Fatigue on Different Implant Lengths in the Rehabilitation of Atrophic Mandibles with Full-Arch Fixed Prosthesis Using Finite Element Method.

This research aimed to evaluate the stress and fatigue generated in short implants compared to regular implants in rehabilitation with fixed full-arch implant-supported prostheses in atrophic mandibles using the finite element method (FEM). Four models were constructed with different implants lengths: 4, 6, 8, and 10 mm. A 100-N oblique load was applied to evaluate the stress on the bone, implant, and prosthetic components. Similar behavior was observed for all groups, except for 4 mm, which showed more discrepant values. During the fatigue test, all the groups exhibited infinite lives except G4. Based on the similarity of all the models, it is suggested that all short implants investigated are seemingly viable alternatives for the rehabilitation of atrophic mandibles. However, the 6-mm-long and 8-mm-long implants evinced more favorable mechanical behavior than the 4-mm-long type.

Does the Length of Mini Dental Implants Affect Their Resistance to Failure by Overloading?

Objective: We aimed to evaluate the failure resistance of different lengths of mini dental implants from the same manufacturer, and to assess their failure following overloading. Materials and Methods: According to the ISO 14801, 15 mini dental implants 2.4 mm in diameter, with lengths of 8.5 mm, 10 mm, or 13 mm, were subjected to compression loading until failure using a universal testing machine. The mean load-to-failure values for each length of the mini dental implants were calculated and analysed using SPSS®, via one-way ANOVA (p < 0.05). Results: The mean load to failure for mini dental implants was 329 N (SD 6.23), 326 N (SD 5.95), and 325 N (SD 6.99) for the 13 mm, 10 mm, and 8.5 mm implants, respectively. A comparison of means showed no significant difference between the groups (p = 0.70). The tested mini dental implants exhibited bending failure modes below the first thread. Conclusion: Under high compressive loading testing, there was no effect of the length on the failure of the mini dental implants following overloading. Moreover, all tested mini dental implants with different lengths showed the same failure mode and distortion location.

P-385 miRNAs and their roles in predicting length and timing of window of implantation

Abstract Study question What are the differences between results from a miRNA-based endometrial receptivity test (MIRA) and a mRNA-based one (ERA)? Summary answer There was a 74.1% concordance between MIRA’s and ERA’s results with additional implications from the select miRNAs that were indicators for window of implantation length. What is known already As more technologies become available, different types of biomarkers have been used to analyze endometrial receptivity such as microRNAs instead of mRNAs. A limitation to these existing technologies is in their ability to determine the length of window of implantation. Patients that are analyzed to be in the post-receptive stage have been seen to have varied lengths of window of implantation. The current solution is to obtain multiple biopsies from an IVF patient in order to confirm the length of their window in order to provide a suggestion on how to alter their embryo transfer time. Study design, size, duration 58 endometrial tissue biopsy samples were analyzed with MIRA. These results were compared to ERA to calculate concordance. Additional analysis was performed by comparing individual miRNA biomarkers between shortened and average window of implantation samples. 11 post-receptive samples with a successful embryo transfer were chosen. Second biopsies for these samples with a “receptive” result indicated “average” window of implantation, while a “ pre-receptive” result from the second biopsy indicated a “shortened” window of implantation. Participants/materials, setting, methods Endometrial tissue biopsy samples were collected from residual clinical samples that had previously undergone ERA testing. The residual tissue samples’ RNA was extracted and analyzed via a multiplex, quantitative qPCR-based platform called NextAmp™ to profile the expression profiles of 96 miRNA biomarkers on MIRA’s testing panel. The subsequent raw expression profiles were analyzed through a proprietary algorithm in order to determine the endometrial stage of the patient (pre-receptive, receptive, or post-receptive). Main results and the role of chance Concordance between the two tests was 74.1%. Further analysis of the individual miRNAs on MIRA’s panel identified 2 down-regulated and 7 up-regulated differentially expressed miRNAs that had potential acting as indicators for shortened window of implantation. The identified differentially expressed miRNAs were based on fold change (log2) = &amp;gt; 0.585 or &amp;lt; -0.585 and p-value = &amp;lt; 0.05 (t-test). Of the 9 identified differentially expressed miRNAs, KEGG analysis was performed to explore their implications in more depth. The end of the secretory phase of the endometrium is usually characterized by phenomena such as degradation of the stromal network (MMP catalysis), infiltration of the stroma by leukocytes, cessation of glandular activity, and apoptosis throughout the tissue. Through KEGG pathway analysis results, pathways that implicate these characterizations were identified such as ECM-receptor interaction, cellular senescence, necroptosis, adherens junctions, and gap junction. With these findings, we see that the 9 miRNAs identified are potential regulators of the morphological changes that occur at the end of the secretory phase in the endometrium, and by monitoring their expression levels can be early indicators of an advanced end to the secretory phase, implying a shortened window of implantation. Limitations, reasons for caution Larger studies should be performed in order to confirm these findings as the current study sample size is limited. Additionally, this only takes into account post-receptive patients; therefore, the same analysis should also be done on patients that fall in the pre-receptive and receptive stages when undergoing endometrial receptivity testing. Wider implications of the findings In this preliminary study, we see that miRNAs could act as potential future biomarkers for identifying shortened window of implantations for patients through endometrial receptivity testing, cutting out the need for multiple biopsies when identifying patients’ windows of implantation. Trial registration number not applicable

Biomechanical Evaluation of Bone Atrophy and Implant Length in Four Implants Supporting Mandibular Full-Arch-Fixed Dentures.

Residual alveolar ridge resorption often occurs after tooth extraction, which causes issues requiring further prothesis rehabilitation. A treatment concept referred to as all-on-four, involving fixed dentures supported with four implants, was recently developed. The current study aimed to determine the effect of changing bone atrophy and implant length in all-on-four treatments on stress and strain in the surrounding bone of the implant. A three-dimensional finite element method was used in this research. The stress analysis was conducted with von Mises stress values. Two types of synthetic jawbone models with mild and moderate atrophy were used. Furthermore, two different implant lengths with a similar implant design and diameter were selected, and they were classified into eight models. Then, the bone model was assessed via a computed tomography (CT) scan and was transformed into a virtual model in Geomagic and SolidWorks with implant rebuilding. After modifying bone atrophy, the von Mises stresses in the surrounding bone of the implant were as follows: mild type 2 < mild type 3 < moderate type 3 < moderate type 4. The bone quantity change rate increased more than when bone conditions were limited. Compared with changes in implant lengths, the stresses in the peri-implant surrounding bone were generally higher in the 9 mm implant length group than in the 11.5 mm group. However, the results did not significantly differ. In conclusion, the von Mises stress and strain increased in the models with moderate atrophy and low-density trabecular bone. Hence, bone atrophy and its presurgical diagnosis in long-term implant prognosis are crucial.

A Retrospective Analysis of Implants with Low Insertion Torque in Immediately Loaded Full-Arch Fixed Prostheses with Corresponding Occlusal Schemes.

Poor alveolar bone quality and quantity may cause low insertion torque during implant placement; therefore, a delicate occlusal design is important for the immediate loading procedure. This retrospective clinical study aimed to investigate (1) the proportion of implants with a low insertion torque between the maxilla and mandible, (2) factors affecting implants with a low insertion torque, and (3) survival rates of implants with a low insertion torque value (< 35 Ncm) using different occlusal designs with full-arch fixed prostheses supported by immediately loaded implants. Between 2013 and 2017, patients who received full-arch reconstructions were treated with immediately loaded one-piece fixed prostheses supported by four to six implants. Full-arch fixed prostheses with at least one immediately loaded regular implant with a low insertion torque value were included in this study. The fixed provisional acrylic prosthesis with a rigid framework was delivered within 3 to 5 days after surgery. According to the distribution of implants with low insertion torque, provisional prostheses were divided into three groups with different occlusal schemes. Definitive prostheses were fabricated after 3 months of loading. A total of 144 patients were treated; 608 and 304 regular implants were inserted in 118 maxillae and 76 mandibles, respectively. Moreover, 42 patients (11 men and 31 women) with 39 maxillae and 4 mandibles were included in this study. The proportion of implants with low insertion torque values in the maxilla was significantly greater than that in the mandible (10.5% vs 1.6%, respectively, P < .001). Implant length and low insertion torque value had no significant correlation (P = .948). Implants with a 3.3-mm diameter (narrow platform) had a greater proportion of low insertion torque values than 4-mm-wide implants (P = .002). Implants placed in a fresh socket had a greater proportion of insertion torque values ≥ 35 Ncm (P = .023). The overall cumulative implant survival rate was 98.6%. Groups 1, 2, and 3 had 14, 23, and 6 provisional prostheses, respectively. The survival rates for implants with insertion torque values < 35 Ncm and ≥ 35 Ncm were 98.4% and 98.7%, respectively, and were not significantly different (P = .866). All prostheses were still functioning during the mean follow-up of 3.7 ± 1.2 years. The high cumulative implant survival rate indicated that implants with a low insertion torque in immediately loaded full-arch provisional prostheses did not jeopardize the outcomes after a corresponding occlusal scheme was used.

Study on friction and wear of preform Z‐directional fiber

AbstractIn order to reduce the wear and tear of Z‐yarn implantation into the preform, the frictional behavior of Z‐yarn during implantation into the preform was studied. According to the actual implantation conditions of Z‐yarns, we designed a guiding array clamping device and a tensile force sensor to study the changes of tensile strength of Z‐yarns at different implantation positions and implantation times, results show that the tensile strength of Z‐yarns decreases significantly after 25 implantations at the position of 4 N friction force, and it's necessary to replace Z‐yarns in time to avoid their fracture in the preform. The use of unadulterated solvent dimethyl silicone oil applied to the Z‐yarns, can significantly reduce their wear, the tensile strength of Z‐yarns after 60 implantations is only 5.6% lower than that of Z‐yarns after 10 implantations. Design the tension control system, and when the tension is 0.46 N, the tensile strength of Z‐yarns during implantation is 34.2% higher than without tension. Meanwhile, the relationship between the normal force applied to Z‐yarn and the implantation length and fiber bundle width are established by combining Hertzian theory and experimental data, and the friction coefficient algorithm during Z‐yarn implantation is derived by combining Howell's equation, which solves the problem that the fiber friction coefficient cannot be measured due to the complicated working condition of Z‐yarn implantation. The frictional wear mechanism of yarn during Z‐yarn implantation into the preform is revealed, and a method to reduce yarn wear and increase its continuous implantation number is proposed.

Extramaxillary Zygomatic Implant Coverage with a Pedicled Buccal Fat Pad Flap Through a Tunnel Approach: A Prospective Case Series.

To describe the benefits of covering the extrasinusal length of extramaxillary zygomatic implants with a pedicled buccal fat pad flap through a tunnel approach. Four extramaxillary zygomatic implants were placed in 10 patients and loaded immediately with an acrylic provisional fixed prosthesis. The extrasinusal length of every implant was covered with a pedicled buccal fat pad flap. Study variables were implant survival rate, peri-implant soft tissue recession (PISTR), peri-implant soft tissue condition (PISTC), modified Bleeding Index (mBI), and suppuration. The statistical analysis comprised the Brunner-Langer model of longitudinal data for each variable and the analysis of variance to assess main effects and interactions. All the zygomatic implants showed osseointegration, resulting in a survival rate of 100%. The PISTR was evaluated after surgery (T0) and after 12 months (T1), statistically significant differences being observed (P = .014). Recession also depended on specific implant positioning; zygomatic implants in the anterior were found to have a higher risk of recession vs implants in the posterior (P = .065). The PISTC was assessed at T0 and T1, and no statistically significant changes were observed (P = .718). Bleeding on probing was present in 10% of the implants at T0 and in 15% at T1, the difference being nonsignificant (P = .317). The use of a pedicled buccal fat pad flap to cover the extrasinusal length of extramaxillary zygomatic implants appears to reduce the risk of soft tissue recession and exposure of the implant surface to the oral cavity.

Evaluation of Sinus Pneumatization and Dental Implant Placement in Atrophic Maxillary Premolar and Molar Regions.

This study aimed primarily to examine the relationship between maxillary sinus variations and dental implant placement in the atrophic maxillary premolar-molar region. Secondly, the preferences of experienced clinicians with regard to implant length in the bone and sinus were evaluated. The data were collected from panoramic radiographs of patients who had undergone dental implant surgery in the posterior maxilla. Parameters such as sinus pneumatization level, sinus floor elevation operation type, and length of dental implants in the sinus and bone (in millimeters) were evaluated. Groups were created for the categories mild-moderate-medial pneumatization and severe-extreme-medial pneumatization, with the subgroups severe and extreme medial pneumatization for medial pneumatization and "5 to 10 mm" and "≤ 5 mm" for inferior pneumatization of the maxillary sinus. The distribution of the data was evaluated with the Shapiro-Wilk test, and the Mann-Whitney U test was used to evaluate the millimeter measurements made in the groups. The mean implant length in bone tissue was measured as 6.3 mm in the mild-moderate-medial pneumatization group and 5.4 mm in the severe-extreme-medial pneumatization group (P < .001), whereas the mean implant length in the sinus was 3.6 mm in the mild-moderate-medial pneumatization group and 3.9 mm in the severe-extreme-medial pneumatization group, respectively (P < .001). The mean implant length in the sinus was 3.0 mm in the 5 to 10 mm group and 5.1 mm in the ≤ 5 mm group (P < .001), whereas the mean implant length in bone was measured as 6.6 mm in the 5 to 10 mm group and 3.6 mm in the ≤ 5 mm group (P < .001). This was the first study in the literature in which classifications of inferior and medial pneumatization of the maxillary sinus were used for the same implants and their correlation was evaluated in the presence of sinus pneumatization. In this study, the mean implant length in the sinus was measured to be greater as sinus pneumatization progressed medially. Therefore, like inferior pneumatization, medial pneumatization may also have risks attributable to the need for internal or external sinus elevation operations in the atrophic maxilla, and this could be easily underestimated if CBCT is not used.

Retrospective analysis of the predictability of using three-dimensional models for preoperative planning of the length of zygomatic implants.

This present study aimed to retrospectively evaluate the predictability of using three-dimensional models (TDMs) to plan the preoperative lengths of zygomatic implants (ZIs). The records of all patients that received such implants between March 2007 and March 2019 were evaluated. The ZI lengths predicted on the TDMs were compared to the lengths of the implants the patients received. In total, the records of 74 patients were evaluated, of which 37 records met the criteria of inclusion, and were included in the study. Twenty-seven (73%) of the patients were female and 10 (27%) were male, ranging from 34 to80 years of age, with the average age being 55.7 years. Seventeen (43.2%) of these patients were classified as ASA I and 21 (56.8%) as ASA II. A total of 142 ZIs were planned and installed in the time frame mentioned. Without distinguishing the region of the maxilla, the implants used were, on average, 1.1 mm larger in length than those initially planned. Overall, the data indicates moderate agreement between the planned and surgical lengths of the ZIs and indicates that using TDMs is a predictable and reliable preoperative planning technique of the length of posterior ZIs.

Bone Ongrowth of Contemporary Cementless Tibial Components: ARetrieval Analysis.

BackgroundCementless total knee arthroplasty is gaining interest as total knee arthroplasty patients become younger, more active, and interested in long-term biologic fixation. New porous coatings have altered mechanical properties to improve bone osseointegration, although limited data exist on this topic. We measured the bone ongrowth on retrieved tibial trays to determine how demographic, radiographic, or implant design factors correlate with ongrowth.Material and methodsTwenty retrieved trays were assessed from 3 designs: Zimmer NexGen Trabecular Metal (n = 9), Stryker Triathlon Tritanium (n = 6), and Biomet Vanguard Regenerex (n = 5). Exclusion criteria included revision for aseptic loosening or early postoperative infection. Ongrowth on the tibial components and on corresponding pegs (if accessible) was assessed. The amount of osseointegration was reported as the bone directly opposed to the surface divided by the available area for ongrowth. Radiographs were reviewed for alignment and regions of biologic fixation.ResultsBone ongrowth covered 65% ± 19% of the tibial tray surface and did not differ among manufacturers (P = .27). Medial pegs had less ongrowth than lateral pegs (39% vs 64%, P = .02). Vanguard medial pegs had less ongrowth than NexGen medial pegs (15% vs 61%, P = .03). Length of implantation was different between the NexGen (55 months) and Triathlon (24 months, P < .05) design only. Patient and radiographic data demonstrated no correlation with ongrowth.ConclusionAn average 65% of the porous tibial tray surface had ongrowth at revision. These values are consistent with manufacturing claims for excellent bone ongrowth for newer porous coatings.