scholarly journals Biomechanical Effects of Diameters of Implant Body and Implant Platform in Bone Strain around an Immediately Loaded Dental Implant with Platform Switching Concept

2019 ◽  
Vol 9 (10) ◽  
pp. 1998
Author(s):  
Hsuan Lung ◽  
Jui-Ting Hsu ◽  
Aaron Yu-Jen Wu ◽  
Heng-Li Huang
Keyword(s):  
Dental Implants ◽  
Lateral Load ◽  
Strain Gauges ◽  
Bone Strain ◽  
Vertical Load ◽  
Artificial Bone ◽  
Implant Stability ◽  
Loading Test ◽  
Platform Switching ◽  
Post Hoc

Dental implants designed with platform switching have been used clinically to reduce crestal bone resorption. The aim of this study was to determine the biomechanical effects of loading types, diameter of platform, and implant diameter in bone strain around immediately loaded implants with platform switching concept. Platform-switching features of dental implants with various diameters of implant body and implant platform (named as RP5.0, RP4.3, and NP3.5) were inserted into artificial bone blocks. The initial implant stability was confirmed using a Periotest device before the loading test. Rosette strain gauges were placed on the alveolar region around the implants, and peak values of the bone strain during a 190-N vertical load or 30-degree lateral load were measured by a data acquisition system. The Kruskal-Wallis test and post-hoc pairwise comparisons were performed as statistical analyses. The median Periotest values of the RP5.0, RP4.3, and NP3.5 implants ranged from −6.59 to −7.34. The RP5.0 implant always showed the lowest bone strain around the implant, regardless of whether a vertical or lateral load was applied. Relative to the RP4.3 and NP3.5 implants, the RP4.3 implant produced a higher bone strain (by approximately 8%) under a vertical load but a lower bone strain (by approximately 25%) under a lateral load. This study confirmed that using a wider implant could relieve the bone strain around an immediately loaded implant with platform switching concept especially under lateral loading.

A Study on the Safety of Carbody for Railway Vehicles

2014 ◽  
Vol 627 ◽  
pp. 409-412 ◽  
Author(s):  
Sung Cheol Yoon ◽  
Yeon Su Kim
Keyword(s):  
Structural Strength ◽  
Compressive Load ◽  
Frequency Measurement ◽  
Load Test ◽  
Rolling Stock ◽  
Strain Gauges ◽  
Vertical Load ◽  
Maximal Strength ◽  
Loading Test ◽  
Major Equipment

To check the structural strength of the carbody of the newly–made gondola car, load was added to the underframe of the gondola car. The objective of this study is to evaluate whether or not the underframe of a gondola car under the maximal strength is safe. A gondola car for transporting railroad freight is usually designed and made of SM490YA steel and SS400 steel. The carbody of rolling stock is a principal structure that supports major equipment of the underframe and the freight. Therefore, the strength evaluation of this structure is important. Both structural analysis and loading test were performed under the loading condition. Prior to the evaluation of structural strength, finite element method software was used for structural analyses on stress distribution in a carbody of a gondola car. The strain gauges were attached on the carbody based on FEM results. A vertical load test, compressive load test, measurement of deflection amount and a natural frequency measurement test were conducted.

Influence of moderate cigarette-smoking on the peri-implant clinicoradiographic inflammatory parameters around cement- and screw-retained dental implants

2020 ◽  
Author(s):  
Mana Alqahtani
Keyword(s):  
Cigarette Smoking ◽  
Dental Implants ◽  
Smoking History ◽  
Inflammatory Parameters ◽  
Significant Difference ◽  
Implant Retention ◽  
Level Of Significance ◽  
Soft Tissue Inflammation ◽  
Post Hoc ◽  
Adjustment Test

The aim was to assess the influence of moderate cigarette-smoking on the clinical (bleeding on probing [BoP] and probing depth [PD]) and radiographic (crestal bone resorption [CBR]) around cement- and screw-retained dental implants at 5 years’ follow-up. A questionnaire was used to collect information about age, gender, smoking history, duration of implants in function, jaw location of the implant, and daily toothbrushing and flossing. Peri-implant BoP, PD and CBR were measured in all groups. Group comparisons were performed using one-way analysis of variance and for multiple comparisons, the Bonferroni Post hoc adjustment test was performed. Level of significance was set at P<0.05. Forty-eight patients (25 smokers and 23 non-smokers) had cement-retained dental implants; and 48 (24 smokers and 24 non-smokers) had screw-retained dental implants. Among patients with cement and screw-retained dental implants, PD (P<0.05) and CBR (P<0.05) were significantly higher among smokers than non-smokers. The peri-implant sites that demonstrated BoP were statistically significantly higher among non-smokers (P<0.05) than smokers among patients with cement- and screw-retained dental implants. There was no statistically significant difference in peri-implant PD and CBR among smokers with cement- and screw-retained dental implants. Among non-smokers with cement and screw-retained dental implants, there was no statistically significant difference in BoP, PD and CBR. Cigarette-smoking is associated with an increased PD and CBR around cement- and screw-retained dental implants. Cigarette-smoking increases peri-implant soft tissue inflammation as well as loss of crestal bone and this relationship is independent of the type of implant retention protocol used.The author recommends that cement- and screw-retained dental implants are suitable for prosthesis restoration in non-smokers. Further studies on dual-smokers (individuals smoking cigarettes and other forms of tobacco products) are needed related to the clinicoradiographic inflammatory parameters around cement- and screw-retained dental implants

scholarly journals Comparative radiographic and resonance frequency analyses of the peri-implant tissue after dental implants placement using flap and flapless techniques: An experimental study on domestic pigs

2013 ◽  
Vol 70 (6) ◽  
pp. 586-594 ◽  
Author(s):  
Zoran Vlahovic ◽  
Branko Mihailovic ◽  
Zoran Lazic ◽  
Mileta Golubovic
Keyword(s):  
Bone Resorption ◽  
Resonance Frequency ◽  
Dental Implants ◽  
Dental Implant ◽  
Surgical Techniques ◽  
Primary Stability ◽  
Implant Stability ◽  
Domestic Pigs ◽  
Flap Technique ◽  
Implant Placement

Background/Aim. Flapless implant surgery has become very important issue during recent years, mostly thanks to computerization of dentistry and software planning of dental implants placements. The aim of this study was to compare flap and flapless surgical techniques for implant placement through radiographic and radiofrequency analyses. Methods. The experiment was made in five domestic pigs. Nine weeks following domestic pigs teeth extraction, implants were placed, on the right side using surgical technique flap, and flapless on the left side. Digital dental Xrays were applied to determine primary dental implant stability quality (ISQ). At certain intervals, not later than three months, the experimental animals were sacrificed, and just before it, control X-rays were applied to measure dental implants stability. Results. Radiographic analysis showed that peri-implant bone resorption in the first 4 weeks following placement implants with flap and flapless surgical techniques was negligible. After the 3 months, mean value of peri-implant bone resorption of the implants placed using flap technique was 1.86 mm, and of those placed using flapless technique was 1.13 mm. In relation to the primary dental implant stability in the first and second week there was an expected decrease in ISQ values, but it was less expressed in the dental implants placed using the flapless technique. In the third week the ISQ values were increased in the dental implants placed by using both techniques, but the increase in flapless implant placement was higher (7.4 ISQ) than in flap implant placement (1.5 ISQ). The upward trend continued in a 4- week period, and after 3 months the dental implant stability values in the implants placed using flap technique were higher than the primary stability for 7.1 ISQ, and in the implants placed using flapless technique were higher comparing to the primary stability for 10.1 ISQ units. Conclusion. Based on the results of radiographic and resonance frequency analyses it can be concluded that the flapless technique in surgical implants placemat, leads to better results.

Structural Performance of Typical Beam-Column Joints in Yingxian Wood Pagoda - An Experimental Study

2012 ◽  
Vol 517 ◽  
pp. 669-676 ◽  
Author(s):  
Zhi Yong Chen ◽  
En Chun Zhu ◽  
Jing Long Pan ◽  
Guo Fang Wu
Keyword(s):  
Failure Modes ◽  
Least Square Method ◽  
Vital Role ◽  
Least Square ◽  
Shanxi Province ◽  
Structural Performance ◽  
Vertical Load ◽  
Loading Test ◽  
Ancient Wood ◽  
Non Destructive

Yingxian Wood Pagoda, built in 1056, is located in the town of Yingxian County, Shanxi Province, China. It is the oldest and highest standing ancient wood structure in China. The pagoda is octagon-shaped in plan, with a total height of 67.31m and a base diameter of 30.27m. It appears as a five-storeyed structure, but actually consists of nine storeys, with four shorter but stiffer storeys hidden between the five apparent storeys. Yingxian Wood Pagoda was built without any metal connectors like nail, screw, or bolt. Instead, Tenon-Mortise connections and Dou-Gong brackets were used to connect all posts and beams. Tenon-Mortise connections and Dou-Gong brackets have been playing a vital role for the pagoda to resist severe winds, earthquakes and some human-induced disasters for nearly a thousand years. To evaluate the safety of the pagoda, it is, therefore, useful to investigate the structural performance of the beam-column joints, most important for Yingxian Wood Pagoda to resist lateral load. In this study, two models of typical beam-column joints of the pagoda, MBCJ-I and MBCJ-II, were manufactured following a ratio of 3.4 to the prototype of the joints. Non-destructive cyclic loading test of the models under different vertical load and destructive cyclic test of the models under vertical load of 20kN were conducted. The hysteretic stiffness of MBCJ-I was lager than MBCJ-II, and increased linearly with vertical load N. The relationship between and N was obtained by regression of the test results using the least square method. The stiffness of model joint under vertical load was 70.6kN/mm. The failure modes, energy-dissipation performance, moment resistance and bending stiffness of both model joints were derived and discussed.

scholarly journals Stability of dental implants with sandblasted and acid-etched (SLA) and modified (SLActive) surfaces during the osseointegration period

2021 ◽  
Vol 15 (4) ◽  
pp. 226-231
Author(s):  
Gulsum Sayin Ozel ◽  
Ozgur Inan ◽  
Asli Secilmis Acar ◽  
Gamze Alniacik Iyidogan ◽  
Dogan Dolanmaz ◽  
...  
Keyword(s):  
Dental Implants ◽  
Surface Properties ◽  
Resonance Frequency Analysis ◽  
Implant Stability ◽  
Osteoprogenitor Cells ◽  
Implant Placement ◽  
Modified Surfaces ◽  
Surface Measurements ◽  
The Stability ◽  
Over Time

Background. The surface properties of implants are effective factors for increasing the osseointegration and activity of osteoprogenitor cells. This study compared the stability of dental implants with sandblasted and acid-etched (SLA) and modified surfaces (SLActive) using the resonance frequency analysis (RFA). Methods. In a split-mouth design, 50 dental implants with either SLA surface properties (n=25) or modified (SLActive) surface properties (n=25) were placed in the mandibles of 12 patients with a bilateral posterior edentulous area. Implant stability was measured using RFA (Osstell) at implant placement time and every week for 1, 2, and 3 months before the conventional loading time. Results. One week following the implantation, implant stability increased from 70 to 77.67 for SLA and from 71.67 to 79 for SLActive (P<0.05). Stability improved each week except in the 4th week in SLActive surface measurements. No significant differences were observed between the groups at 2 and 3 months (P>0.05). Conclusions. For both implant surfaces, increased stability was observed over time, with no significant differences between the groups.

EXOSKELETAL STRAIN: EVIDENCE FOR A TROT-GALLOP TRANSITION IN RAPIDLY RUNNING GHOST CRABS

1993 ◽  
Vol 179 (1) ◽  
pp. 301-321
Author(s):  
R. Blickhan ◽  
R. J. Full ◽  
L. Ting
Keyword(s):  
Axial Loading ◽  
Maximum Load ◽  
Strain Gauges ◽  
Bone Strain ◽  
Muscular Tension ◽  
Ocypode Quadrata ◽  
Ghost Crabs ◽  
Leg Design ◽  
Treadmill Locomotion

Equivalent gaits may be present in pedestrians that differ greatly in leg number, leg design and skeletal type. Previous studies on ghost crabs found that the transition from a slow to a fast run may resemble the change from a trot to a gallop in quadrupedal mammals. One indication of the trot-gallop gait change in quadrupedal mammals is a distinct alteration in bone strain. To test the hypothesis that ghost crabs (Ocypode quadrata) change from a trot to a gallop, we measured in vivo strains of the meropodite of the second trailing leg with miniature strain gauges. Exoskeletal strains changed significantly (increased fivefold) during treadmill locomotion at the proposed trot-gallop transition. Maximum strains attained during galloping and jumping (1000×10-6-3000×10-6) were similar to the values reported for mammals. Comparison of the maximum load possible on the leg segment (caused by muscular tension) with the strength of the segment under axial loading revealed a safety factor of 2.7, which is similar to values measured for jumping and running mammals. Equivalent gaits may result from similarities in the operation of pedestrian locomotory systems.

scholarly journals Can the Macrogeometry of Dental Implants Influence Guided Bone Regeneration in Buccal Bone Defects? Histomorphometric and Biomechanical Analysis in Beagle Dogs

2019 ◽  
Vol 8 (5) ◽  
pp. 618 ◽  
Author(s):  
Manuel Fernández-Domínguez ◽  
Victor Ortega-Asensio ◽  
Elena Fuentes Numancia ◽  
Juan Aragoneses ◽  
Horia Barbu ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Dental Implants ◽  
Animal Study ◽  
Statistical Significance ◽  
Guided Bone Regeneration ◽  
Biomechanical Analysis ◽  
Implant Stability ◽  
Beagle Dogs ◽  
Implant Placement ◽  
Cervical Portion

The aim of this experimental animal study was to assess guided bone regeneration (GBR) and implant stability (ISQ) around two dental implants with different macrogeometries. Forty eight dental implants were placed within six Beagle dogs. The implants were divided into two groups (n = 24 per group): G1 group implants presented semi-conical macrogeometry, a low apical self-tapping portion, and an external hexagonal connection (whereby the cervical portion was bigger than the implant body). G2 group implants presented parallel walls macrogeometry, a strong apical self-tapping portion, and an external hexagonal connection (with the cervical portion parallel to the implant body). Buccal (mouth-related) defects of 2 mm (c2 condition) and 5 mm (c3 condition) were created. For the control condition with no defect (c1), implants were installed at crestal bone level. Eight implants in each group were installed under each condition. The implant stability quotient (ISQ) was measured immediately after implant placement, and on the day of sacrifice (3 months after the implant placement). Histological and histomorphometric procedures and analysis were performed to assess all samples, measuring crestal bone loss (CBL) and bone-to-implant contact (BIC). The data obtained were compared with statistical significance set at p < 0.05. The ISQ results showed a similar evolution between the groups at the two evaluation times, although higher values were found in the G1 group under all conditions. Within the limitations of this animal study, it may be concluded that implant macrogeometry is an important factor influencing guided bone regeneration in buccal defects. Group G1 showed better buccal bone regeneration (CBL) and BIC % at 3 months follow up, also parallel collar design can stimulate bone regeneration more than divergent collar design implants. The apical portion of the implant, with a stronger self-tapping feature, may provide better initial stability, even in the presence of a bone defect in the buccal area.

scholarly journals Influence of Insertion Torque on Clinical and Biological Outcomes before and after Loading of Mandibular Implant-Retained Overdentures in Atrophic Edentulous Mandibles

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Fernanda Faot ◽  
Amália Machado Bielemann ◽  
Alessandra Julie Schuster ◽  
Raissa Micaella Marcello-Machado ◽  
Altair Antoninha Del Bel Cury ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Dental Implants ◽  
Survival Rates ◽  
Rank Correlation ◽  
Primary Stability ◽  
Insertion Torque ◽  
Success Rates ◽  
Implant Stability ◽  
Before And After ◽  
Edentulous Patients

Aim. To evaluate the influence of primary insertion torque (IT) values of narrow dental implants on the peri-implant health, implant stability, immunoinflammatory responses, bone loss, and success and survival rates. Methods. Thirty-one edentulous patients received two narrow implants (2.9x10mm, Facility NeoPoros) to retain mandibular overdentures. The implants were categorized in four groups according to their IT: (G1) IT > 10 Ncm; (G2) IT ≥ 10Ncm and ≤ 30 Ncm; (G3) IT >30Ncm and < 45Ncm; (G4) IT ≥ 45Ncm, and all implants were loaded after 3 months of healing. The following clinical outcomes were evaluated 1, 3, 6, and 12 months after implant insertion: (i) peri-implant tissue health (PH), gingival index (GI), plaque index (PI), calculus presence (CP), probing depth (PD), and bleeding on probing (BOP); (ii) implant stability quotient (ISQ) by resonance frequency analysis; and (iii) IL-1β and TNF-α concentration in the peri-implant crevicular fluid. The marginal bone level (MBL) and changes (MBC) were evaluated. The Chi2 test, Kruskal-Wallis test, mixed-effects regression analysis, and the Kendall rank correlation coefficient were used for statistical analysis (α = 5%). Results. G1 presented the highest PD at all evaluated periods. G2 presented higher PI at month 6 and 12. G4 showed increased GI at month 3 and 12 and more CP at month 1 (p=.003). G2 and G4 had higher ISQ values over the study period, while those from G1 and G3 presented lower ISQ values. The IL-1β concentration increased until month 12 and was independent of IT and bone type; G4 had a higher IL-1β concentration in month 3 than the other groups (p=.015). The TNF-α release was negatively correlated with IT, and TNF-α release was highest in G1 at month 12. The MBL immediately after surgery and the MBC at month 12 were similar between the groups, and G4 presented a positive MBC at month 12. The survival and success rates were 75% for G1, 81.3% for G2, 64.3% for G3, and 95% for G4. Conclusion. The IT did not influence the clinical outcomes and the peri-implant immunoinflammatory responses and was weakly correlated with the narrow dental implants primary stability. The observed success rates suggest that the ideal IT for atrophic fully edentulous patients may deviate from the standardized IT of 32 Ncm.

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