Top PDF Evaluation of insertion torque of different orthodontic miniscrews: An in vitro study

Evaluation of insertion torque of different orthodontic miniscrews: An in vitro study

Evaluation of insertion torque of different orthodontic miniscrews: An in vitro study

removal torques, and energy required for insertion and removal. 2 However, the high insertion torque of the 3M design could lead to stress in the bone tissue. Some study on finite element analysis showed when some types of mini screws were examined micromotion at the screw/bone interface and bone strain development. Since the resistance of the micro-motion at the mini-screw/bone interface depends on the initial mechanical fixation between the screw and bone, it is likely that high 14 and micro-motion might be caused by early loading. 14,21 The small displacements also suggest that a mini-screw can be immediately loaded, thereby decreasing chair time for clinicians and treatment time for patients. A critical issue related to skeletal anchorage realized with orthodontic mini-screws is the mechanical
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Evaluation of peak insertion torque and dimensional changes of miniscrew implant of varying diameters in different cortical bone thickness:  An in-vitro study.

Evaluation of peak insertion torque and dimensional changes of miniscrew implant of varying diameters in different cortical bone thickness: An in-vitro study.

Cortical bone thickness (CBT) and density can vary according to the region of placement. Areas with thick cortical bone are considered the most stable for MSI placement. Since retention depends essentially on the bone- metal interface, the greater the bone, the better the primary stability. On the other hand, the higher the bone density the greater the bone pressure and bone damage during insertion. Baumgaertel et al 2 found that CBT decreased from anterior to posterior palate and recommends a placement site in premolar region. The same holds for Kang et al 46 who found that the midpalatal area within 1 mm of the midsagittal suture had the thickest bone available in the whole palate. The thickness tended to decrease laterally and posterior. So, when a MSI could deviate from the midpalatal area by more than 1 mm, they recommend placing it not far posterior or using a shorter MSI.
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Comparative evaluation of insertion torque and mechanical stability for self-tapping and self-drilling orthodontic miniscrews – an in vitro study

Comparative evaluation of insertion torque and mechanical stability for self-tapping and self-drilling orthodontic miniscrews – an in vitro study

According to our results, there is a strong correlation between MIT and miniscrew type, probably due to the mini-implant design [17] as well as to the insertion tech- nique, since the use of a pilot drill reduces the insertion torque [15]. Interestingly, while according to literature the greater outer diameter and deeper threads should provide greater MIT and stability [17, 22, 23], in the present experimental setup the self-tapping screws that had an outer diameter of 2.0 mm and an inner diameter of 1.3 mm showed lower MIT values compared to the self-drilling screws having an outer diameter of 1.75 mm and an inner diameter of 1.3 mm. Therefore, the main reason for the MIT values measured can be probably as- cribed to the insertion technique.
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Evaluation of variables affecting distribution of stresses in orthodontic miniscrews and in surrounding cortical/cancellous bone: A Three Dimensional Finite Element Analysis

Evaluation of variables affecting distribution of stresses in orthodontic miniscrews and in surrounding cortical/cancellous bone: A Three Dimensional Finite Element Analysis

parameters such as screw length, head diameter, shank diameter, shank length, shank shape, thread shape and pitch of ten different commercially available miniscrews. Bio mechanical parameters such as cortical bone thickness, insertion angle, drilling depth was also considered in evaluating the Von-misses stresses and the deformation of the screws. A force value of 1 N was applied perpendicular to the implant was applied to the miniscrews. They concluded that the direction of the applied forces had a limited influence on the stresses produced and geometric parameters such as head diameter, diameter of the shaft, thread pitch had an important relation to the Von -misses stresses produced. According to the authors an ideal implant should have a diameter of 2mm, cylindrical shape, short and wide head, short and wide shank and appropriately sized threads. The present study agrees with two of its conclusions, the diameter affecting the stress values and the direction of applied forces had no effect.
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An In-Vitro Comparison of Different Palatal Sites for Orthodontic Miniscrew Insertion: The Effect of Bone Quality and Quantity on Primary Stability

An In-Vitro Comparison of Different Palatal Sites for Orthodontic Miniscrew Insertion: The Effect of Bone Quality and Quantity on Primary Stability

Cadaveric studies present with inherent limitations including the alteration in bone substance by the preservation medium, the absence of bone remodeling and factors related to the age or cause of death. The preservation medium can alter the bone characteristics and influence IT values. A study investigating dental implants using human cadavers reported higher insertion torque values in formalin-fixed bone than fresh-frozen human bone. 146 However, the objective of the current study was to identify the most favorable palatal insertion sites with regards to IT and to determine the effects of BMD, BT and LSE on these values rather than to report palatal IT values that might be expected clinically. While IT values may be affected by specimen preparation, the findings provide some insight into palatal sites that may be more optimal for OMS primary stability. In addition, any error relating to bone preservation should influence all insertion sites and the comparisons made within the study remain valid. Extrapolation of the findings from this study to living individuals is limited, and as such, the use of fresh- frozen human specimens may be more favorable for OMS stability testing.
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Evaluation of Frictional Forces Generated between Three
Different Ligation Methods with Four Different Sizes of
Orthodontic Archwires: An In Vitro Study

Evaluation of Frictional Forces Generated between Three Different Ligation Methods with Four Different Sizes of Orthodontic Archwires: An In Vitro Study

friction and conventional system are minimal. These differences become significant when correction of a misalignment greater than 3.0 mm is attempted. Robert J. Nikolai et al., (2009) 44 examined the influence of third order torque on kinetic friction in sliding mechanics involving active and passive Self- Ligating Brackets. Wire slot frictional forces were quantified and compared across five sets of brackets and tubes within a simulated posterior dental segment with-15 0 , -10 0 ,-5 0, 0 0 ,+5 0 , +10 0 , +15 0 of torque placed in the second premolar bracket ,a working archwire was pulled through the slots. Increasing the torque produced significant increase in frictional resistance with all five sets of brackets and tubes. At 0 0 and 5 0 of torque, generally less friction was created within the passive than within the active self-ligating bracket sets, and the conventional bracket sets with elastomeric ligation generated the most friction. At 10 0 of torque, apparently with wire -slot clearance eliminated, all bracket- and-tube sets displayed similar resistances, with one exception at +10 0 . At 15 0 of torque, one active set and one passive set produced significantly larger frictional resistance than the other three sets. Thus it was concluded that third order torque in posterior dental segments can generate frictional resistance during anterior retraction with the archwire sliding through self-ligating bracket slots. With small torque angles, friction is less with passive than with active self-ligating brackets, but bracket design is a factor. Frictional forces are substantial, regardless of ligation if the wire-slot torque exceeds the third-order clearance.
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An In-Vitro Study Evaluating the Fracture Resistance and Insertion Torque of Self-Drilling Mini-Implants Upon Insertion Into Synthetic High Density Mandibular Bone.

An In-Vitro Study Evaluating the Fracture Resistance and Insertion Torque of Self-Drilling Mini-Implants Upon Insertion Into Synthetic High Density Mandibular Bone.

The use of mini-implants (also known as temporary anchorage devices (TADs), miniscrews, microscrews, and micro-implants) has become a valuable and prevalent part of orthodontic treatment. They are an adjunctive device that can be inserted into specific intra-oral bony structures, to provide a form of anchorage whose purpose is to prevent unwanted tooth movements. Mini-implants have expanded treatment possibilities by decreasing dependence on patient compliance, reducing unwanted tooth movements, and introducing previously unattainable tooth movements such as molar intrusion and distalization. 1-4 Due to their rapidly growing presence in the orthodontic field, mini-implants have become a routine part of everyday clinical orthodontics for many practitioners, and are amongst the most frequently discussed topics in orthodontic literature today.
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Evaluation of deflection characteristics of mini implants following placement: An Ex-vivo study

Evaluation of deflection characteristics of mini implants following placement: An Ex-vivo study

characteristics, orthodontic mini screw designs, and primary stability. Four different miniscrews of sizes 1.7x10mm, 1.65 x9mm, 1.6x10mm and 1.8x10mm were placed in pig ribs. The miniscrews were first scanned with a scanning electron microscope to obtain measurable images of their threads and then inserted to a depth of 7mm. Maximum insertion torque and pull out force was measured for each screw. A positive correlation between the pitch of the mini screw and maximum insertion torque values was found. A strong correlation between maximum insertion torque and pullout force was noted. A direct correlation among cortical thickness, marrow bone density, and pullout force was observed. Differences in cortical bone thickness were more relevant for initial stability of the miniscrews than cortical bone quality.
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Influence of interradicular and palatal placement of orthodontic mini-implants on the success (survival) rate

Influence of interradicular and palatal placement of orthodontic mini-implants on the success (survival) rate

Survival rates based on Kaplan-Meier estimates were calculated from day of insertion until day of implant loss, early or scheduled removal of mini-implants. 59 OMIs were either lost or removed prematurely. Analysis of survival rates for the anterior palate compared to inter-radicular insertion sites demonstrated a better per- formance of palatal OMIs (Fig. 3). Those remained in place for 24.4 months on average. Interradicular inser- tion showed higher loss rates in the first 13 months with an average survival of 17.4 months. The correlation be- tween insertion site and the failure rate of OMIs was statistically significant ( p < 0.001). The results of the Cox-Regression are displayed in Table 3.
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Miniscrew appliances and their use in orthodontics

Miniscrew appliances and their use in orthodontics

hexidine digluconate, should also be applied to the area where the miniscrew is to be placed to maintain asepsis. Placement should take place under local anesthesia, with just a small injection inside the mouth being sufficient to achieve the anesthetic effect. If the patient mentions sen- sitivity while the miniscrew is being inserted, this may be because the miniscrew has made contact with a tooth root [6]. However, perforation can be avoided by consid- ering redirecting the screw. Careful planning and radio- graphic evaluation of the placement site can minimize this risk. Before inserting the miniscrew, the inexperi- enced orthodontist is advised to use a periapical x-ray in conjunction with a bent guidewire in the area selected for the insertion. Fabrication of a bar to serve as a guide is another option (Figure 1). These landmarks may remain during the surgery. The experienced orthodontist, how- ever, will be able to place a miniscrew without such landmark guides [1]. Miniscrew insertion should take into account the relationship between the interradicular bone and the length of the screw to be embedded in the cortical bone. A miniscrew placed near the cementoe- namel junction has less interradicular space available than one inserted near the tooth apex instead. For optimal retention and effectiveness, the screw should be inserted with a 5 mm inclination towards the cementoenamel junction and at an angle of more than 45˚ towards the tooth apex [3,7].
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Shear bond strength of a bracket-bonding system cured with a light-emitting diode or halogen-based light-curing unit at various polymerization times

Shear bond strength of a bracket-bonding system cured with a light-emitting diode or halogen-based light-curing unit at various polymerization times

SBS measurement, several factors can influence the results. This in vitro study fails to simulate factors such as intraoral aging of resin composites, PH and temperature fluctua- tion based on individual’s dietary intake and oral hygiene, complex cyclic loading, microbial attack and enzymatic degradation. Pickett et al 50 and Murray and Hobson 51 found

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Correction ofSkeletal OpenbiteUsingZygomaticMiniplates

Correction of Skeletal Openbite Using Zygomatic Miniplates

To obtain an absolute anchorage, temporary anchorage devices (TADs), including miniplates and miniscrews, have been used recently as orthodontic anchorage to intrude the maxillary posterior teeth to allow autorotation of the mandible and bite closure [7-12]. Miniscrews are frequently used for orthodontic anchorage However, their disadvantage is an approximately 15% failure rate, which is primarily attributed to the low mechanical stability between the miniscrew and cortical bone and to the miniscrew's close proximity to the dental root [13]. Recent studies show that, The failure rate for miniplates was significantly lower than for miniscrews [14].
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EVALUATION OF THE INFLUENCE OF DIFFERENT IMPLANT ANGULATIONS ON THE ACCURACY OF AN IMPRESSION RECORDED USING VARIOUS VISCOSITIES OF ADDITION SILICONE IMPRESSION MATERIAL-AN IN-VITRO STUDY

EVALUATION OF THE INFLUENCE OF DIFFERENT IMPLANT ANGULATIONS ON THE ACCURACY OF AN IMPRESSION RECORDED USING VARIOUS VISCOSITIES OF ADDITION SILICONE IMPRESSION MATERIAL-AN IN-VITRO STUDY

MATERIALS AND METHODOLGY: Four sets of two implant analogues were placed parallel to each other at various angulations at 0 0, 5 0 ,10 0 ,15 0 .Sample size -64 and p value <0.05. Definitive impressions were made using vinyl polysiloxane of different consistencies with the following impression techniques. Soft putty body and light body, heavy body and light body, medium body and Bite registration along with soft putty body and light body .Profile projector was used to measure the distance between two reference points.

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Insertion torque recordings for the diagnosis of contact between orthodontic mini-implants and dental roots: a systematic review

Insertion torque recordings for the diagnosis of contact between orthodontic mini-implants and dental roots: a systematic review

Because of these characteristics and because the target condition is created during the index test procedures, it will be possible to address a variety of research questions from the same data set. Answers should be first sought in cadaver and in vivo animal studies. A detailed trans- parent protocol has to be developed for this purpose that includes input from (1) the items presented in our ‘Discussion’ section of the QUADAS-2 tool; (2) the figure for the potential new diagnostic pathway for assessing implant-root contact (Fig. 6); (3) the STARD checklist [53]; (4) ASTM International [34]; (5) our protocol with the tailored QUADAS-2 tool [60]; and (6) a variety of stakeholders, e.g. patients, clinicians, researchers, the pay- ing party, and manufacturers [54, 62]. Measuring insertion torque during the entire insertion process and the report- ing of adverse effects of interventions should become key elements of such protocols [32].
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An evaluation of two different methods of coccygectomy in patients with traumatic coccydynia

An evaluation of two different methods of coccygectomy in patients with traumatic coccydynia

The analysis of the study data was made with SPSS 20 soft- ware (IBM Corporation, Armonk, NY, USA). Conformity to normal distribution of unit numbers was assessed with the Shapiro–Wilk test. In the interpretation of the results, the sig- nificance level of 0.05 was used: a value of p< 0.05 indicated that variables were not of normal distribution and p> 0.05 indi- cated normal distribution of the variables. In the examination of differences between groups where the variables were not normally distributed, the Mann–Whitney U test was applied. The correlations between variables not of normal distribution were examined with Spearman’s correlation analysis. A value of p> 0.05 was accepted as statistically significant.
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Genetic Diversity and Dendrogram of Cardiospermum Halicacabum- An In Vitro Study

Genetic Diversity and Dendrogram of Cardiospermum Halicacabum- An In Vitro Study

other another work carried out in shodhganga, the C.halicacabum collected from the western ghats and forest regions of India showed less genetic variation. The UPGMA dendrogram for five selected populations of C. halicacabum collected from five different regions of kerala showed two clusters. Accessions from Trivandrum, Kanyakumari and Kollam were grouped in one cluster whereas populations from Alappuzha and Palakkad in the other cluster (M.S. Sheeba et al., 2014).

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Evaluation of Concentration Dependent Antimicrobial Efficacy of Herbal and Non Herbal Dentifrices Against Salivary Microflora – An In Vitro Study

Evaluation of Concentration Dependent Antimicrobial Efficacy of Herbal and Non Herbal Dentifrices Against Salivary Microflora – An In Vitro Study

In our study, the antimicrobial efficacy was similar in herbal and non-herbal tooth pastes and also in their different concentrations. Based on another study by Mahesh R. K. et al, there is a trend to believe that the herbal toothpastes possess significant salivary glucose inhibitory activity and favor transient increase in salivary ph. 49 The anti-plaque and anti-gingival effects

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The Use of Micro-Computed Tomography for Evaluation of Internal Adaptation of Dental Restorative Materials in Primary Molars: An In-Vitro Study

The Use of Micro-Computed Tomography for Evaluation of Internal Adaptation of Dental Restorative Materials in Primary Molars: An In-Vitro Study

series of X-ray images along continuous planes are captured from a rotating object to obtain 3D of the interior microstructures of small objects with high spatial resolution. These measurements have nondestructive nature, which permits further evaluation on the intact samples. It is considered as an important tool in many academic laboratories and industrial researches. [24-26] In biomedical field research, micro-CT has been used for examining a wide range of specimens including mineralized tissue such as bones and teeth, materials such as ceramics and polymers. In the field of tissue engineering, it is useful to show the structural features in scaffolds and the resulted tissue regeneration. [27, 28] Regarding dental materials, micro-CT has been used to investigate the structures at tooth-restoration interfaces for evaluation of polymerization shrinkage, internal adaptation and microleakage of the dental restoration. It gives the 3D reconstruction of the whole dental restoration and the surrounding dental tissues. [28, 29]
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Quantifying Resistance to Sliding in Orthodontics: A Systematic Review

Quantifying Resistance to Sliding in Orthodontics: A Systematic Review

Archwires sliding through brackets with various static amounts of 1 st , 2 nd or 3 rd order of angulation (mostly evaluated separately). Studies of this group assess the contribution of bracket, archwire, and ligation types to RS while fixing orders of angulation at quantified increments, allowing the investigation of the influence of various amounts of angulation and displacement on RS [16,51-54]. Sliding mechanics during deflection, misalignment or malocclusion were the basic clinical concepts simulated in this group besides the tipping generated after the alignment phase. Archwire guided bodily OTM undergoes a force in the opposite direction of movement generated by tissue surrounding the root, leading to a tooth rotation around its center of resistance (tipping) [3]. Eventually, this will increase the load at the contact points between wire and bracket, and elastic deformity of archwire, producing anti- tip and anti-rotational movements of the teeth [3,11]. In some designs, approximated dental centers of resistance have been simulated to indirectly quantify second-order angulation effects of a stationary bracket relative to a linear archwire traction [11,55,56]. A quantified moment is generated to create a proportional second- order angulation which is –in this case- not directly quantified but rather indirectly described in terms of the induced second-order moment. Again, an accurate simulation of OTM during the alignment phase is technically difficult because the displaced tooth does not remain in its position during alignment, and tooth movement is 3D in space. Due to this, tooth displacements and angulations are expressed apart in vitro. In the case of a static fixed amount of tipping, the anti-tip (uprighting) moment created in vivo by the elastic deformation at the bracket/archwire
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Evaluation of Arch Dimensional Changes After Orthodontic Treatment in Extraction and Non-extraction Cases. An in-vitro Study

Evaluation of Arch Dimensional Changes After Orthodontic Treatment in Extraction and Non-extraction Cases. An in-vitro Study

mesio-incisal tip of the most prominent incisor as the reference points. A total of 100 (Group 1- Upper bicuspid extraction=50; Group 2- Non-extraction=50) orthodontically treated cases were selected in the age range of 19-25 years (Males=50; Females=50). Their pre and post treatment study models were collected and photographed. The photographic data was then digitized and arch dimensional changes were measured using AUTO CAD. The data obtained were subjected to statistical analyses using Paired t-test, Unpaired t-test,Levene's test and Gain score measurement test. There were significant antero-posterior tooth movements in extraction cases when compared to non extraction cases, a significant reduction in the intermolar width after premolar extractions but minimal changes in the intercanine width showing significance at 5% level. In non-extraction cases, there was no significant arch dimensional changes after orthodontic treatment in both intermolar and intercanine region. Maximum antero-posterior arch dimensional changes can be seen in orthodontically treated bicuspid extraction cases and non extraction cases show minimal changes in the antero-posterior dimensions even after orthodontic treatment. Significant amount of anchorage loss can be seen in upper bicuspid extraction cases when compared to non extraction cases. Reduction in the intermolar width and contraction of maxillary arch occurred in upper bicuspid extraction cases with minimal changes in the intercanine width. Minimal transverse arch dimensional changes occurred in non-extraction cases after orthodontic treatment.
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