Reverse Torque Research Articles

Evaluation of the effect of oral health care product on the reverse torque value of the titanium prosthetic screw of an implant-supported crown following cyclic loading

Purpose of the study: To comparatively evaluate in vitro the effect of oral health care product on the reverse torque value of the titanium prosthetic screw of an implant-supported crown following cyclic loading. Materials and methods: Ten titanium screw-retained implant Co-Cr crowns without application of oral health care product (Group I) and ten titanium screw-retained implant Co-Cr crowns with the application of oral health care product (GC Tooth Mousse) (Group II) were connected to their respective analogs and prosthetic screws were torqued to 30 Ncm using a digital torque meter. Reverse Torque Values were measured before cycling loading and all the twenty samples were subjected to a cyclic loading simulating six months’ duration of the function. Reverse Torque Values were subsequently measured postcyclic loading. The results were analyzed using the Paired ‘t’ test and the Independent ‘t’ test. Results: The mean precyclic loading reverse torque values were 26.12 Ncm (Group I) and 26.57 Ncm (Group II) and the mean postcyclic loading reverse torque values were 22.49 Ncm (Group I) and 24.10 Ncm (Group II). There was no significant loss of preload for Group II test samples prior to cyclic loading compared to Group I test samples. Cyclic loading resulted in reduction of reverse torque values for both Group I and Group II test samples, indicating screw loosening. After cyclic loading, Group II test samples showed significantly higher detorque value than Group I test samples. Conclusion: Cyclic loading resulted in screw loosening in both test groups. Screw loosening was found to be significantly less for Co-Cr prosthetic screw-retained implant crown with the application of GC Tooth Mousse than Co-Cr prosthetic screw-retained implant crown without application of GC Tooth Mousse.

Physical and mechanical changes on titanium base of three different types of hybrid abutment after cyclic loading.

This study investigated the physical and mechanical changes in the titanium base of three different hybrid abutment materials after cyclic loading by estimating the post-load reverse torque value (RTV), compressive side fulcrum wear pattern of titanium base, and surface roughness. A total of 24 dental implants were divided into three groups (n = 8 each): Group Z, LD, and P used zirconia, lithium disilicate, and polyetheretherketone, respectively, for hybrid abutment fabrication. RTV was evaluated after cyclic loading with 50 N for 1.2 × 106 chewing cycles. The compressive sides of the titanium bases were analyzed using a scanning electron microscope, and the roughness of the affected areas was measured using an optical profilometer after loading. Datasets were analyzed using Kruskal-Wallis test followed by Mann-Whitney tests with the Bonferroni correction (α = .05). Twenty-three samples passed the test; one LD sample fractured after 770,474 cycles. Post-load RTV varied significantly depending on the hybrid-abutment material (P = .020). Group P had a significantly higher median of post-load RTVs than group Z (16.5 and 14.3 Ncm, respectively). Groups LD and P showed minor signs of wear, and group Z showed a more pronounced wear pattern. While evaluating compressive side affected area roughness of titanium bases, lower medians were shown in group LD (Ra 0.16 and Rq 0.22 µm) and group P (Ra 0.16 and Rq 0.23 µm) than in group Z (Ra 0.26 and Rq 0.34 µm); significant differences were found only among the unaffected surface and group Z. The hybrid abutment material influences the post-load RTV. Group Z had a more pronounced wear pattern on the compressive side of titanium base; however, the surface roughness was not statistically different among the hybrid-abutment groups.

Effect of Abutment Cooling on Reverse Torque Values of Abutment Screws: An In Vitro Study.

Purpose: To evaluate the effect of cooling on the reverse torque values of different abutments in bone-level and tissue-level implants. The null hypothesis was that there would be no difference in reverse torque values of abutment screws when cooled and uncooled implant abutments were compared. Materials and Methods: Bone-level and tissue-level implants (Straumann, each n = 36) were placed in synthetic bone blocks and subdivided into three groups (each n = 12) based on the abutment type (titanium base, cementable abutment, abutment for screw-retained restorations). All abutment screws were tightened to 35 Ncm torque. In half of the implants, a dry ice rod was applied on the abutments close to the implant-abutment connection for 60 seconds before untightening the abutment screw. The remaining implant-abutment pairs were not cooled. The maximum reverse torque values were recorded using a digital torque meter. The tightening and untightening procedure was repeated three times for each implant including cooling for the test groups, resulting in 18 reverse torque values per group. Two-way analysis of variance (ANOVA) was used to analyze the effect of cooling and abutment type on the measurements. Post hoc t tests were used to make group comparisons (α = .05). The P values of post hoc tests were corrected for multiple testing using the Bonferroni-Holm method. Results: The null hypothesis was rejected. Cooling and abutment type significantly affected the reverse torque values in bone-level implants (P = .004) but not in tissue-level implants (P = .051). The reverse torque values of bone-level implants significantly decreased after cooling (20.31 ± 2.55 Ncm vs 17.61 ± 2.49 Ncm). Overall mean reverse torque values were significantly higher in bone-level implants compared to tissue-level implants (18.96 ± 2.84 Ncm vs 16.13 ± 3.17 Ncm; P < .001). Conclusion: Cooling of the implant abutment led to a significant decrease in reverse torque values in bone-level implants and may therefore be recommended as a pretreatment before the application of procedures to remove a stuck implant part.

Comparison of reverse torque values of abutment screws with the application of oil-based and water-based antibacterial agents.

Using antibacterial agents to remove the foul odor of the implant cavity and prevent peri-implantitis can affect the detorque values and lead to the loosening of the abutment screw. This study investigated the effects of tetracycline and chlorhexidine gel on detorque values. This in vitro study was carried out on three groups of five implants. Group G1 was the control group, and no material was applied to the implant cavity. In group G2, the implant cavity was first filled with artificial saliva and then with chlorhexidine gel. In group G3, the implant cavity was first filled with artificial saliva and then with tetracycline. The abutments were tightened with 25 N/cm2 and then loosened. Finally, the detorque values were calculated. The highest detorque values were recorded in group G1. Group G3 showed the lowest detorque values. ANOVA showed significant differences in mean detorque values (P<0.05) between the three groups. According to this study, applying antibacterial agents decreased the detorque values and increased the risk of screw loosening. The reduction of detorque values was more pronounced with the oil-based antibacterial agent (tetracycline).

Full arch immediate occlusal loading using site specific implants: A clinical series of 10 patients (13 arches).

Osseointegration of dental endosseous implants has proven to be effective, predictable, and clinically successful. Unloaded healing protocols were originally used in treating edentulous patients. Full arch immediate occlusal loading protocols have been shown to be as effective as unloaded healing protocols. This paper reports on the results, benefits, and limitations of one specific immediate loading protocol using site specific implants for fresh extraction and healed extraction sites. Ten consecutive patients [{13 arches} (age range: 64-81 years; average: 70.1) (4males/6 females) were treated by the first 2 authors in private practice settings. Hopeless teeth were scheduled for extraction with immediate implant placement and immediate loading with insertion of full arch, screw-retained, acrylic resin interim prostheses within 24 hours. Implants were also placed into healed edentulous ridges. Insertion torque values for each implant were recorded. Interim prostheses were removed after at least 3 months of healing. Implants were reverse torque tested (35 Ncm) and evaluated for macroscopic mobility. Definitive full arch prostheses were made. Patients were followed for 21 to 48 months postimplant surgery. Panoramic radiographs were taken immediately postimplant placement and 1 year postoperative. Thirteen arches were treated; 11 ultrawide diameter implants were placed into molar sockets, 26 inverted body-shift implants were placed into anterior sockets; 25 standard diameter, tapered implants were placed into edentulous sites; 2 zygomatic implants were placed in one patient. The total number of implants placed was 64 (4preexisting implants were also used and not included in this study). The minimum implant insertion torque value was 20 Ncm. After 12 to 18 months of function (average 14 months), the implant and prosthetic survival rates were 100%. Eight patients were restored with definitive zirconia or acrylic resin hybrid fixed prostheses. Two patients were restored with bar titanium frameworks and removable overdenture prostheses. No prosthetic complications were reported for the definitive prostheses. The results of this clinical series with site specific implants and immediate full arch occlusal loading in treating edentulous patients resulted in 100% clinical implant and prosthetic survival rates. According to this study, this protocol can be used with high levels of anticipated success.

Osseointegration Levels of Implants Placed With Allogenic and Xenogenic Bone Ring: An Experimental Biomechanical Analysis.

This in vivo study aimed to do a biomechanical analysis of the early period bone-implant connection of titanium implants simultaneously inserted with xsenogenic and allogenic bone ring. In this study, 28 Sprague Dawley female rats were used. Four rats were killed to obtain an allogenic bone ring, and after this, the remaining rats were divided into control (n=8), xsenogenic (n=8), and allogenic (n=8) bone ring groups. Titanium-machined surfaced implants were integrated right tibias of the rats. In controls, only implants were integrated into right tibias. In the greft groups, the implants were integrated simultaneously with bone rings. After 2 weeks of the experimental period, the rats were killed ,and titanium implants and surrounding bone tissues were removed for biomechanic analysis. After biomechanical reverse torque analysis bone-implant connection was determined as Newton/cm 2 ; in controls 3.26 (1.2 to 4.5), in allogenic ring group 3.37 (2 to 4.4), in xsenogenic ring group 5.93 (2.8 to 10). Statistically significant differences were not detected between the groups ( P >0.05). Within the limitation of this study, both allogenic and xsenogenic bone grafts could be successfully used in bone augmentation in implant surgery.

Creating stable trapping force and switchable optical torque with tunable phase of light.

Light-induced rotation of microscopic objects is of general interest as the objects may serve as micromotors. Such rotation can be driven by the angular momentum of light or recoil forces arising from special light-matter interactions. However, in the absence of intensity gradient, simultaneously controlling the position and switching the rotation direction is challenging. Here, we report stable optical trapping and switchable optical rotation of nanoparticle (NP)-assembled micromotors with programmed phase of light. We imprint customized phase gradients into a circularly polarized flat-top (i.e., no intensity gradient) laser beam to trap and assemble metal NPs into reconfigurable clusters. Modulating the phase gradients allows direction-switchable and magnitude-tunable optical torque in the same cluster under fixed laser wavelength and handedness. This work provides a valuable method to achieve reversible optical torque in micro/nanomotors, and new insights for optical trapping and manipulation using the phase gradient of a spatially extended light field.

Preload evaluation of 2 implant-supported fixed partial denture abutment designs

Statement of problemA hemi-engaging abutment design has been suggested to improve the stability of the implant-to-abutment interface compared with that of a fully nonengaging design to restore implant-supported fixed partial denture. However, controversy persists regarding the benefit of using a hemi-engaging abutment design and prompts the need for specific mechanical testing on the effect of these designs on screw preload under simulated clinical conditions. PurposeThe purpose of this in vitro study was to determine whether significant differences in preload values of the screw before and after cyclic loading exist between hemi-engaging and nonengaging abutment fixed partial denture designs. Material and methodsTwenty-four conical connection implants measuring 4.3×10 mm (Nobel Biocare Replace Conical Connection; Nobel Biocare) were mounted in acrylic resin blocks. Specimens were divided into 2 groups. An experimental group included 12 three-unit fixed partial dentures with a hemi-engaging design; a control group included 12 three-unit fixed partial dentures with the conventional design of 2 nonengaging abutments. A digital screw torque meter was used to measure screw torque values per the manufacturer’s recommendation of 35 Ncm. Reverse torque value was measured before cyclic loading and referred to as initial preload. After cyclic loading, reverse torque value was measured and referred to as final preload. The effect of cyclic loading was evaluated by averaging the reverse torque value across the 2 screws in each specimen and then calculating the changes between the initial preload and final preload. The difference between initial and final preload was referred to as reverse torque difference. An additional reverse torque difference, referred to as reverse torque difference-nonengaging, was calculated for the nonengaging screws in each experimental specimen and for 1 randomly selected screw of the 2 in each control specimen. Preload efficiency before and after cyclic loading was also calculated. All groups went through cyclic loading using a universal testing machine. The specimens went through axial loading first, and then the reverse torque value was measured. Twenty-four new abutment screws were then used, and the specimens then went through lateral loading at 30 degrees. Load was applied to the units (1.0×106 cycles) for each loading axis. The statistical significance of differences between the axial and lateral reverse torque difference and between the 2 groups of reverse torque difference and reverse torque difference-nonengaging were assessed using Mann-Whitney U tests (α=.05). ResultsA comparison of reverse torque difference between loading types revealed no significant difference (P=.773). Therefore, data for the 2 loading types were combined before comparing the reverse torque difference and reverse torque difference-nonengaging values between the 2 groups based on abutment design (12 hemi-engaging designs in the experimental group and 12 fully nonengaging designs in the control group). The experimental group mean reverse torque difference was -0.65 ±1.95 Ncm (range -4.0 to 2.4 Ncm), and the control group mean reverse torque difference was -2.5 ±5.44 Ncm (range -15.3 to 5.3 Ncm). No significant difference was found (P=.340). Furthermore, no significant difference was found between the reverse torque difference for the nonengaging screw in each of the 12 implants with a hemi-engaging design versus 1 randomly selected nonengaging screw in each of the 12 implants with a fully nonengaging design (P=.355). ConclusionsNo significant difference was found in screw preload between a hemi-engaging and a full nonengaging 3-unit fixed partial denture supported by conical connection implant configurations before and after cyclic loading.

Comparative Evaluation of Osseodensification Versus Conventional Osteotomy Technique on Dental Implant Primary Stability: An Ex Vivo Study.

Purpose One of the commonest treatment options for replacing missing teeth is a root-form implant. Clinically, the key mechanical factor in achieving success is primary stability. This ex vivo study aims to evaluate whether osseodensification method will achieve good primary stability or the conventional drilling protocol. Methods Fresh iliac bone of the sheep was selected similar to D3 and D4 bone densities. A total of 22 osteotomy sites were prepared in the bone sample, of which 11 were prepared by osseodensification method (test group) and other 11 by conventional undersized drilling (control group). Primary stability was measured using insertion torque (IT), resonance frequency analysis (RFA), and reverse torque values (RTVs) by measuring implant stability quotient (ISQ). The recorded data were statistically analyzed using Statistical Package for the Social Sciences (SPSS) Version 22.0. The differences between groups were compared using the Mann-Whitney U test and independent t-test. The Pearson correlation coefficient test was performed to measure the linear relationship between two variables. The statistical significance level was established at p<0.05. Results When the correlation among IT, RTV, and ISQ was measured, a statistically significant correlation between IT and RTV (p=0.001) and between IT and ISQ (p=0.0001) was observed. A statistically significant (p=0.014) correlation between RTV and ISQ was also found. Conclusion Osteotomy prepared by osseodensification method showed higher IT, RTV, and ISQ values than the conventional undersized group.

Design and Development of Savonius Turbine for STEM Education

There are very few initiatives to engage students in learning about the sustainability of wind energy through Science, Technology, Engineering, and Mathematics education, also known as STEM. This awareness is essential for future generations to instill interest and understanding in the significance of sustainable energy. Therefore, a practical, hands-on Savonius turbine demonstration kit has been designed for Science, Technology, Engineering, and Mathematics (STEM) education. Two models of drag-driven vertical axis 2-bladed and 3-bladed Savonius turbines were built to generate electricity and integrated with a model house as part of the STEM turbine kit. It was fabricated in-house and could display power using LED lights and actuating a few mechanical devices. The experimental study in this project aims to investigate and analyze the influence of the number of blades on turbine power performance in terms of power coefficient and torque coefficient with respect to tip speed ratio. The results revealed that the 3-bladed Savonius turbine has a higher power coefficient than the 2-bladed at a tip speed ratio of 0.109. However, the torque coefficient decreased as the tip speed ratio increased due to an increase in the number of blades that eventually created a reverse torque. It is also observed that the 3-bladed turbine generated the highest power output of 1.28 Watt at a speed of 38.8 m/s. The results also discovered that all the components could run more efficiently using the 3-bladed Savonius turbine. This kit demonstrates the ability to contribute to the education system in developing countries, such as Malaysia by supporting the construction of an engaging educational process with practical integration and low production costs.

Study on Aerodynamic Characteristics of a Savonius Wind Turbine with a Modified Blade

In order to improve the static start-up problem of Savonius wind turbines, a Savonius wind turbine with a modified blade is proposed. It was obtained by twisting the half-cylindrical blades of the basic Savonius wind turbine by 70°. The aerodynamic performance of the wind turbine before and after the modification was compared. Firstly, the static torque coefficient of two wind turbines at different azimuth angles were obtained by means of three-dimensional numerical simulation. The static flow field around the wind turbine was analyzed. Then, the output power and speed characteristics of a spiral Savonius wind turbine under different incoming wind speeds were evaluated in the wind tunnel. The results show that, compared with the Savonius wind turbine with half-cylindrical blades, the spiral wind turbine could start at any azimuths in one rotation cycle. The reverse torque was eliminated. The static torque coefficient fluctuation range was reduced by 10%. The start-up performance was effectively improved. This investigation could provide guidance for the improvement of start-up characteristics of Savonius wind turbines.

Calculation and Analysis of Reverse Torque of the Earth Pressure Balance Shield

Calculation and Analysis of Reverse Torque of the Earth Pressure Balance Shield

Optimal Design of Power-On Downshift Control of Series-Parallel Hybrid Transmission Based on Motor Active Speed Regulation

Multi-speed transmission is the main development direction of hybrid transmission, which has brought higher shift quality requirements than traditional fuel vehicle transmission. However, there is less research on the shifting control of hybrid transmission, especially for the shifting control of dedicated hybrid transmission (DHT), which uses the wet clutch as a shift element. This paper studies the power-on downshift process of a two-speed series-parallel hybrid transmission, proposes a shifting control strategy based on motor active speed regulation, and deeply analyzes the causes of maximum impact during the shifting process. The results show that the reverse torque produced in the process of eliminating the remaining slip is the root cause of the maximum impact. On this basis, two optimization strategies are proposed to reduce the shift impact and improve the shift quality. The simulation results show that the proposed optimization strategies can effectively suppress the shift impact. In the meanwhile, for any control pressure of the OG (off-going) clutch in the speed phase within the range of (2.44–2.53 bar), a high shift quality in which the maximum impact is controlled lower than 10 m/s3 can be achieved, which has high engineering value and practical significance.

Fatigue Life Analysis of Main Reducer Gears for Battery Electric Bus Considering Regenerative Braking

The braking mode of the battery electric urban bus (BEUB) is different from the friction braking of the traditional fuel bus due to the introduction of a regenerative braking system. The intervention of electromagnetic braking changes the working condition of the main reducer gears, thus affecting their service lives. Based on the Urban Dynamometer Driving Schedule (UDDS) driving cycle condition, the stress–time history of the main reducer gears is calculated. Combined with the static analysis results and the S-N curve of the material, the fatigue lives of the main reducer gears considering electromagnetic braking and traditional friction braking are analyzed. The reverse torque on the driving axle during electromagnetic braking is taken into account to be closer to the real situation. Results show that, under the electromagnetic braking mode, the bending fatigue lives of the tooth root on the convex and concave surfaces of the pinion are 78.5% and 78.9% of that under the traditional friction braking mode, respectively, while the contact fatigue life of the pinion working surface is 78.2% of that under the friction braking mode, indicating that the introduction of the regenerative braking system into the BEUB will cause a significant reduction in the service life of the main reducer gears. This study provides a high-precision fatigue life calculation method for the BEUB main reducer gears and the accurate prediction of their remaining life.

Non-Destructive Removal of Dental Implant by Using the Cryogenic Method.

Background and Objectives: The gold standard for a successful prosthetic approach is the osseointegration of an implant. However, this integration can be a problem in cases where the implant needs to be removed. Removing the implant with minimal damage to the surrounding tissues is important. Osteocytes cannot survive below −2 °C, but epithelial cells, fibroblasts, and other surrounding tissue cells can. Remodeling can be triggered by cryotherapy at temperatures that specifically affect osteocyte necrosis. In this study, we aimed to develop a method for reversing the osseointegration mechanism and for protecting the surrounding tissues by bone remodeling induced by CO2 cryotherapy. Materials and Methods: In this study, eight 2.8 mm diameter, one-piece mini implants were used in New Zealand rabbit tibias. Two control and six implants were tested in this study. After 2 months of osseointegration, a reverse torque force method was used to remove all osseointegrated implants at 5, 10, 20, and 30 Ncm. The osseointegration of the implants was proven by periotest measurements. Changes in bone tissue were examined in histological sections stained with toluidine blue after rabbit sacrifice. The number of lacunae with osteocyte, empty lacunae, and lacunae greater than 5 µm and the osteon number in a 10,000 µm2 area were calculated. Cryotherapy was applied to the test implants for 1 min, 2 min, and 5 min. Three implants were subjected to cryotherapy at −40 °C, and the other implants were subjected to cryotherapy at −80 °C. Results: Empty lacunae, filled osteocytes, lacunae >5 µm, and the osteon count around the implant applied at −40 °C were not significantly different from the control implants. The application of −40 °C for 1 min was found to cause minimal damage to the bone cells. The implants, which were applied for 1 min and 2 min, were successfully explanted on the 2nd day with the 5 Ncm reverse torque method. Test implants, which were applied cold for 5 min, were explanted on day 1. Tissue damage was detected in all test groups at −80 °C. Conclusions: The method of removing implants with cryotherapy was found to be successful in −40 °C freeze–thaw cycles applied three times for 1 min. To prove implant removal with cryotherapy, more implant trials should be conducted.

Evaluation the loosening of abutment screws in fluid contamination: an in vitro study

Screw loosening is one of the most common clinical problems of dental implants. Research on the influencing factors of screw loosening is very important to prevent screw loosening. The purpose of this in vitro study was to evaluate the influence of liquid contamination on the screw loosening. According to the contamination condition, forty-five abutment screws were divided into three groups (n = 15): no contamination, artificial saliva contamination, and mouthwash contamination. The preload and friction coefficient of the abutment screws were recorded. Then, the reverse torque values (RTVs) and settlement were measured after 3.0 × 105 and 6.0 × 105 cycles. The surface wear of the screws was analyzed. Finally, the stress distribution of the abutment screws was calculated by finite element analysis (FEA). The results showed that fluid contamination reduced the friction coefficient, increased the preload, decrease the settlement, improved resistance to screw loosening, and reduced wear on the thread surface. Appropriate antimicrobial lubrication may improve the anti-loosening performance of abutment screws and prevent excessive wear on the threaded surface.

Evaluation of Implant Stability and Trephination Depth for Implant Removal-An In Vitro Study.

Malpositioned and broken implants are usually fully osseointegrated; hence, their removal, especially from the lower arch, can be very challenging. Implant removal techniques include reverse torque and trephination. Trephination is an invasive technique that can jeopardize vital structures, cause mandibular fatigue fractures, or lead to osteomyelitis. In this study, we aimed to assess the relationship between trephination depth and implant stability by recording implant stability quotient (ISQ) readings at varying trephination depths in vitro. Materials and methods: Forty-eight implants were inserted into dense synthetic polyurethane foam blocks as artificial bone. Primary implant stability was measured with a Penguin resonance frequency analysis (RFA) device. Implants of two designs with a diameter of 3.75 mm and a length of 13 or 8 mm were inserted. Twenty-four internal hexagon (IH) (Seven®) and twenty-four conical connection (CC) implants (C1®; MIS® Implants, Ltd., Misgav, Israel) were used. The primary implant stability was measured with the RFA device. Trephination was performed, and implant stability was recorded at depths of 0, 3, and 6 mm for the 8 mm implants and 0, 3, 6, 8, 10, and 11.5 mm for the 13 mm implants. Results: Linear regression revealed a significant relation between the trephination depth and the ISQ (F (1, 213) = 1113.192, p < 0.001, adjusted r2 = 0.839). The trephination depth significantly predicted the ISQ (β = −5.337, p < 0.001), and the ISQ decreased by −5.33 as the trephination depth increased by 1 mm. Conclusion: Implant stability reduction as measured using an RFA device during trephination may be a valuable guide to achieving safe reverse torque for implant removal. Further studies are needed to evaluate these data in clinical settings.

Evaluation of the effects of the systemic proton pump inhibitor-omeprazole on periimplant bone regeneration and osseointegration: An experimental study

ObjectiveInvestigations of the effects of proton pump inhibitors (PPIs) on bone healing have revealed that they affect bone regeneration negatively. The exact mechanism by which this adverse effect on bone tissue is not known. The aim of this study is to biomechanic and biochemical investigation of the effects of the PPIs on guided periimplant bone regeneration. Material & methodsSpraque dawley rats were divided controls (n = 8): there is no treatment during 8 week experimental period, PPI- Dosage 1 (n = 8) and Dosage 2 (n = 8): 5 mg/kg and 10 mg/kg omeprazol applied 3 times in a week with oral gavage during 8 weeks respectfully. Bone defects created half of the implant length circumferencial after implant insertion and defects filled with bone grafts. After experimental period the rats sacrified and implants with surrounding bone tissues were removed to reverse torque analysis (Newton), blood samples collected to biochemical analysis (glucose, AST, ALT, ALP, urea, creatinin, calcium, P). ResultsBiomechanic reverse torque values did not revealed any statistical differences between the groups (P > 0,05). ConclusionAccording the biomechanical and biochemical parameters PPIs does not effect the periimplant guided bone regeneration.

Biomechanic and biochemical analysis of the effects of local Ankaferd Blood Stopper® application on osseointegration of titanium implants

Aim: Investigations into Ankaferd Blood Stopper® (ABS) on bone healing have revealed positive bone regeneration effects. The exact mechanism of this positive bone tissue metabolism effect is unknown. This study’s aim is a biomechanic and biochemical investigation of the effects of local ABS application on the osseointegration of titanium implants. Methodology: Sprague Dawley rats were divided into four groups of ten rats each. The control group (n=20) received no treatment during the experimental period, while the ABS group (n=20) had ABS applied locally during the surgical application of the titanium implant before insertion into the bone sockets. After 2 (controls n=10 and ABS n=10) and 4 weeks (controls n=10 and ABS n=10) experimental periods, the rats were sacrificed and implants with surrounding bone tissues were removed for reverse torque analysis (Newton), blood sample collection, and biochemical analysis. Results: The biomechanic bone implant contact ratio detected was higher in week 4 than in week 2 in the ABS group (p&lt;0, 05). Lower phosphor levels were detected in the ABS group than in the 4-week controls (p&lt;0, 05). Conclusion: According to the biomechanical parameters, ABS is more effective after four weeks than after two weeks when locally applied. How to cite this article: Özcan EC, Gül M, Tanık A, Yıldırım TT, Özkan M, Bozoğlan A, Özdemir HE, Dündar S. Biomechanic and biochemical analysis of the effects of local Ankaferd Blood Stopper® application on osseointegration of titanium implants. Int Dent Res 2022;12(1):27-33. https://doi.org/10.5577/intdentres.2022.vol12.no1.5 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Fatigue properties of plasma nitriding for dental implant application

Statement of problemFatigue failure of implant components is a common clinical problem. Plasma nitriding, an in situ surface-strengthening method, may improve fatigue properties of dental implants. PurposeThe purpose of this in vitro study was to evaluate the effect of plasma nitriding on the fatigue behavior of implant systems. Material and methodsThe preload and friction coefficient of plasma nitrided abutment screws, as well as settlement of the implant-abutment interface, were measured. Then, the reverse torque values and pullout force were evaluated after cyclic loading. Finally, the fatigue properties of the implant system were investigated with static fracture and dynamic fatigue life tests, and the morphology of the fracture on the surface of the implant system was observed. ResultsThe plasma nitriding treatment reduced the friction coefficient; increased the preload, settlement value, reverse torque values, pullout force, and static fracture load; and prolonged fatigue life. Furthermore, abutment screws with plasma nitriding treatment showed a different fatigue fracture mode. ConclusionsPlasma nitriding improved mechanical performance and may be a suitable way to optimize the fatigue behavior of dental implants.