Comparative Biomechanical Characteristics of Modified Side-to-Side Repair and Modified Pulvertaft Weaving Repair – In vitro Study

2019 ◽  
Vol 24 (01) ◽  
pp. 76-82
Author(s):  
Sudhir Kannan ◽  
Arijit I. Ghosh ◽  
Joseph J. Dias ◽  
Harvinder Pal Singh

Background: Strong surgical repair is the mechanical basis of early mobilization and prerequisite for biological healing following tendon grafting. Side to side and pulvertaft repairs were developed to meets these demands. However, these techniques have later been modified to improve the strength of repair but their characteristics have not been compared. Methods: We compared biomechanical strength of the modified side-to-side (SS) repair with the modified Pulvertaft (PT) repair technique in turkey tendons keeping overlap length, anchor points, type of suture, suture throw and amount of suture similar. Two investigators performed 34 repairs during one summer month to test the tensile strength of the repair using mechanical strength testing machine. Variables measured were maximum load, load to first failure, modulus, load at break, mode of failure, site of failure, tensile strain, tensile stress. The statistical comparison was carried by Levene’s test and T test for means. Results: The mean maximum load for modified SS repair was 50.3 (SD 13.7) N and modified PT repair was 46.9 (SD 16.4) N. The tensile stress at maximum load for SS and modified PT repair was 4.7 (SD 4) MPa and 4.2 (SD 3) MPa respectively. The suture cut through was the commonest mode of failure. Conclusions: We found no statistical difference between 2 repairs in load at which they started failing (p = 0.16), and maximum load repairs could withstand (p = 0.35). Our study uniquely compares two techniques under standard conditions, and contrary to existing evidence found no difference. However, in our opinion the number of anchor points may have a greater impact than number of weaves on the strength.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rafat Bagheri ◽  
Abbas Abbaszadegan ◽  
Mohammad R. Nabavizadeh ◽  
Maryam Ferooz ◽  
Peter Parashos

Abstract Background The aim of this study was to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. Methods Eighty human lower molars were selected and randomly divided into four groups (n = 20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentine volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05. Results There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P < 0.001). Conclusions Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.


2018 ◽  
Vol 55 (3) ◽  
pp. 361-363
Author(s):  
Daniel Alexandru Pop ◽  
R. Malaescu ◽  
Liviu Marsavina ◽  
Tiberiu Hosszu ◽  
Raul Rotar ◽  
...  

The aim of this in vitro study is to compare the load-to-fracture performance of polymethyl methacrylates (PMMA) provisional restorations manufactured with a traditional laboratory technique in comparison to a computer-assisted design and computer-assisted manufacturing (CAD-CAM) technique. Five interim three-unit fixed dental prostheses were fabricated with the conventional indirect technique, on a standard typodont. The same model was scanned with an intraoral scanner and the digital design of identical fixed dental prostheses was made. Then other five interim three-unit fixed dental prostheses were milled from PMMA CAD/CAM blocks with an in office milling machine. All specimens were tested for flexural strength in a universal testing machine, and the maximum load to fracture was measured. For the conventional provisional restorations, the load to fracture was 121.16 � 24.6, in comparison to CAD/CAM interim restorations, for which the load to fracture was 728.88 � 228.7. Within the limitations of this study, one can conclude that CAD/CAM provisional restorations present a higher fracture load than the conventional manufactured interim restorations.


2016 ◽  
Vol 7 (3) ◽  
pp. 119-122
Author(s):  
K Pradeep ◽  
MA Kuttappa ◽  
Adarsh Kudva ◽  
Roshni Butula

ABSTRACT Objectives The objective of this study is to measure and compare the compressive strength of two bulk-fill posterior composites (Smart dentin replacement or SDR and Filtek bulk fill) with universal nanohybrid composite (Filtek Z 250XT). Materials and methods In this in vitro study, three different types of posterior composites are used as follows: Group 1 – SDR (Dentsply, Konstanz, Germany); group 2 – Filtek bulk-fill (3M ESPE, St. Paul, MN, USA); group 3 – Filtek Z-250XT (3M ESPE, St. Paul, MN, USA). Ten cylindrical samples of 6 mm height and 4 mm diameter in each group were made using a split brass mold. The composites filled in the brass mold were photopolymerized using light-emitting diode (LED) light-curing unit and the cured samples were stored in water at 37°C for 48 hours before testing. The compressive strength of the stored samples was tested using universal testing machine (Instron 3366, UK) at a cross-head speed of 0.5 mm/minute. The compressive strength was calculated by dividing the maximum load with area of the samples. Results Results are statistically analyzed using one-way analysis of variance (ANOVA) with Tukey's post hoc test. Analysis showed that SDR and Filtek bulk-fill have greater compressive strength than Filtek Z-250 (p < 0.05). However, there is no statistical difference between compressive strength of SDR and Filtek bulk-fill composites (p > 0.05). How to cite this article Pradeep K, Ginjupalli K, Kuttappa MA, Kudva A, Butula R. In vitro Comparison of Compressive Strength of Bulk-fill Composites and Nanohybrid Composite. World J Dent 2016;7(3):119-122.


2021 ◽  
Author(s):  
Rafat Bagheri ◽  
Abbas Abbaszadegan ◽  
Mohammad R Nabavizadeh ◽  
Maryam Ferooz ◽  
Peter Parashos

Abstract Background: This study aimed to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. Methods: Eighty human lower molars were selected and randomly divided into four groups (n=20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentin volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05.Results: There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P <0.001). Conclusions: Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.


Author(s):  
Mohmed Isaqali Karobari ◽  
Ahmad Fareez Abdul Aziz ◽  
Saleem D. Makandar ◽  
Nik Rozainah Nik Abdul Ghani ◽  
Mohamad Syahrizal Halim ◽  
...  

Abstract Objective This article evaluates the fracture resistance of teeth with different endodontic access cavities and conducts literature review on the effects of truss endodontic cavity. Material and Methods Eighty human mandibular first molars were assigned randomly to four groups (n = 20); group 1: truss access cavity (TrussAC); group 2: conservative access cavity (ConsAC); group 3: traditional access cavity (TradAC); and group 4: served as control (no access). Accesses were prepared in groups 1 to 3, respectively. Endodontic treatment was performed on all accessed teeth and composite restoration placed. Teeth in all groups were loaded until fracture using a mechanical testing machine. The maximum load at fracture and patterns of fracture were recorded. Additionally, a literature search was performed on studies related to TrussAC and its importance. Statistical Analysis Fracture strengths were compared using one-way analysis of variance complemented by Bonferroni test. Fracture patterns were analyzed using chi-square test. Results TradAC showed significantly lower mean load at fracture than TrussAC, ConsAC, and intact teeth. Fracture resistance of teeth with TrussAC and ConsAC was not significantly different. All three test groups showed significantly more frequent unrestorable fractures. The literature review revealed that TrussAC did not improve the fracture strength significantly; however, pulp chamber debridement was significantly impaired. Conclusion TrussAC improved the fracture strength of endodontically treated teeth, but not significantly as compared to ConsAC. Restorable fractures were more in intact teeth compared with all prepared ones.


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.


Author(s):  
A. Olivier ◽  
J. Wannenburg ◽  
R.D. Gottschalk ◽  
M.J. Van der Linde ◽  
H.T. Groeneveld

A shoe was designed to combine the advantages of a reverse shoe and an adjustable heart bar shoe in the treatment of chronic laminitis. This reverse even frog pressure (REFP) shoe applies pressure uniformly over a large area of the frog solar surface. Pressure is applied vertically upward parallel to the solar surface of the frog and can be increased or decreased as required. Five clinically healthy horses were humanely euthanased and their dismem-bered forelimbs used in an in vitro study. Frog pressure was measured by strain gauges applied to the ground surface of the carrying tab portion of the shoe. A linear variable distance transducer (LVDT) was inserted into a hole drilled in the dorsal hoof wall. The LVDT measured movement of the third phalanx (P3) in a dorsopalmar plane relative to the dorsal hoof wall. The vertical component of hoof wall compression was measured by means of unidirectional strain gauges attached to the toe, quarter and heel of the medial hoof wall of each specimen. The entire limb was mounted vertically in a tensile testing machine and submitted to vertical downward compressive forces of 0 to 2500 Nat a rate of 5 cm/minute. The effects of increasing frog pressure on hoof wall weight-bearing and third phalanx movement within the hoof were determined. Each specimen was tested with the shoe under the following conditions: zero frog pressure; frog pressure used to treat clinical cases of chronic laminitis (7 N-cm); frog pressure clinically painful to the horse as determined prior to euthanasia; frog pressure just alleviating this pain. The specimens were also tested after shoe removal. Total weight-bearing on the hoof wall at zero frog pressure was used as the basis for comparison. Pain-causing and pain-alleviating frog pressures decreased total weight-bearing on the hoof wall (P < 0.05). Frog pressure of 7 N-cm had no statistically significant effect on hoof wall weight-bearing although there was a trend for it to decrease as load increased. Before loading, the pain-causing and pain-alleviating frog pressures resulted in a palmar movement of P3 relative to the dorsal hoof wall compared to the position of P3 at zero frog pressure (P < 0.05). This difference remained statistically significant up to 1300 Nload. At higher loads, the position of P3 did not differ significantly for the different frog pressures applied. It is concluded that increased frog pressure using the REFP shoe decreases total hoof wall weight-bearing and causes palmar movement of P3 at low weight-bearing loads. Without a shoe the toe and quarter hoof wall compression remained more constant and less in magnitude, than with a shoe.


2018 ◽  
Vol 6 (9) ◽  
pp. 1707-1711
Author(s):  
Rami M. Atia ◽  
Nada Omar ◽  
Haidy Nabil ◽  
Yousra Aly

OBJECTIVE: The aim of this in vitro study was to assess the effect of obturation technique and cementation timings on the bonding of fibre-reinforced posts to the root canal walls. METHODS: Twenty extracted teeth were randomly allocated to two groups according to the obturation technique and cementation timing. Central incisors with single canals were used after being decoronated. Every extracted tooth of the {vertical compaction group} (VC) group (n = 10) had been obturated using the {E & Q plus obturation system} with posts cemented in the same day; The other (CO) conventional group (n = 10) teeth were obturated using the conventional lateral compaction technique and posts cemented after one week. “SF“ Fiber posts were used after bonding and cementation using Rely X ARC resin cement with all the endodontically treated teeth. The push-out test was performed in a universal testing machine. Data were analysed by 2 way analysis of variance with Statistical significance was set to 0.05. RESULTS: Heat softened gutta percha group showed more push out the bond strength of the bonded posts than the conventional obturation group (p < 0.05). In the middle region, there was no statistical significance between the two groups while there was significance in the coronal and apical thirds. CONCLUSION: The vertical compaction technique and early cementation improved the bond strength of the resin posts in comparison to the conventional obturation technique with late cementation.


2007 ◽  
Vol 21 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Ana Cristina Soares Santos ◽  
André Tortamano ◽  
Sandra Regina Frazatto Naccarato ◽  
Gladys Cristina Dominguez-Rodriguez ◽  
Julio Wilson Vigorito

This in vitro study was designed to compare the forces generated by commercially available elastomeric chains and NiTi closed coil springs, and to determine their force decay pattern. Forty elastomeric chains and forty NiTi closed coil springs were divided into 4 groups according to the following manufacturers: (1) Morelli®, (2) Abzil®, (3) TP Orthodontics® and (4) American Orthodontics®. The specimens were extended to twice their original length and stored in artificial saliva at 37°C. Initial force was measured by means of an Instron universal testing machine and then at 1, 4, 7, 14, 21, and 28 days. The results revealed that the elastomeric chains delivered a mean initial force of 347 g for Morelli®, 351 g for American Orthodontics®, 402 g for Abzil®, and 404 g for TP Orthodontics®. The NiTi closed coil springs generated a mean initial force of 196 g for American Orthodontics®, 208 g for TP Orthodontics®, 216 g for Abzil®, and 223 g for Morelli®. The mean percentage of force decay observed after 28 days for the elastomeric chains was 37.4% for TP Orthodontics®, 48.1% for American Orthodontics®, 65.4% for Morelli®, and 71.6% for Abzil®. After 28 days, the NiTi closed coil springs presented a mean percentage of force decay of 22.6% for American Orthodontics®, 29.8% for Abzil®, 30.6% for Morelli®, and 45.8% for TP Orthodontics®. At the end of the study, significant differences were observed between the elastomeric chains and the NiTi closed coil springs. The results indicated that the studied NiTi closed coil springs are more adequate for dental movement than the elastomeric chains.


2015 ◽  
Vol 5 (1) ◽  
pp. 22-26
Author(s):  
Muzin Shahi Shaik ◽  
Snigdha Pattanaik ◽  
Sudhakar Pathuri ◽  
Arunachalam Sivakumar

Introduction: Bond strength is an important property and determines the amount of force delivered and treatment duration in orthodontics. Many light-cured bonding materials are being used; but it is required to determine the most efficient one withdesired bond strength. Objective: To determine and compare the shear bond strength of three visible light-cured composites (Transbond XT, Heliositand Enlight) and two self-cured composites (Rely-a-bond and Concise). Materials & Method: 100 extracted premolars were collected and randomly divided into 5 test groups of different adhesives. Brackets were bonded to the teeth in each test group with the respective adhesive according to the manufacturer’s instructions. Each specimen was debonded using Universal Testing Machine and the shear bond strength for each specimen was calculated. All the groups were compared by ANOVA one-way test. Results: There were statistically significant differences among the five groups (P<0.05). The shear bond strength of Enlight (13.92 ± 3.92) is similar to Transbond XT (14.30 ± 4.35). Conclusion: Light cure composites showed higher bond strength than self cure composites.


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