Dental Materials
Sherin Johnson; Sameena Begum; SM Laxmikanth; Raghunandan Chunduri; Khadeer Riyaz; Anju Varughese
Abstract
Aim: This study evaluated the effect of physical and chemical sterilization techniques on the fracture resistance of mini-implants.Methods: Thirty-two titanium mini-implants of 1.5 x 8 mm were randomly divided into four groups: control, steam sterilized, dry heat sterilized, and chemically sterilized. ...
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Aim: This study evaluated the effect of physical and chemical sterilization techniques on the fracture resistance of mini-implants.Methods: Thirty-two titanium mini-implants of 1.5 x 8 mm were randomly divided into four groups: control, steam sterilized, dry heat sterilized, and chemically sterilized. The samples were then tested in the air for fracture resistance using a universal testing machine. A tangential load was applied to the head of the mini-implant with a 1 mm/min crosshead speed after blocking each of them in the machine. Also, the maximum load was recorded previous to screw fracture. he Kruskal-Wallis test and Mann-Whitney post hoc test were used for data analysis.Results: The results of this study demonstrated the mean fracture resistance difference between the four groups was statistically significant at p<0.001. Moreover it was showed the control group had significantly higher mean fracture resistance compared to dry heat and chemically sterilized groups at p=0.001 and p=0.009 respectively. This was followed by the stem sterilized group demonstrating significantly higher mean fracture resistance as compared to dry heat and chemically sterilized groups at p=0.001 and p=0.01 respectively. Later, the chemically sterilized group also showed significantly higher mean fracture resistance as compared to the dry heat group at p=0.002. However, no significant difference was observed between the control and stem sterilized groups (p=0.29).Conclusion: The steam sterilized group demonstrated the highest fracture resistance that was followed by the chemically sterilized group, and the least with the dry heat sterilized group.
Biomechanics
Prerna Pahuja; Divya Yadav; Harshita Gupta; Gurkeerat Singh; Monika Dahiya; Arisha Izhar; Akanksha Shukla; Deepali Bisht
Abstract
Aim: Among various retraction methods for space closure in first premolar extraction, the palatal approach is preferred to labial appliances in cases having high aesthetic demand. A finite element model and clinical randomized prospective trial was undertaken to determine the possibility of en-masse ...
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Aim: Among various retraction methods for space closure in first premolar extraction, the palatal approach is preferred to labial appliances in cases having high aesthetic demand. A finite element model and clinical randomized prospective trial was undertaken to determine the possibility of en-masse retraction of maxillary anterior teeth using palatal TAD and a clear aligner-like appliance in patients undergoing extraction of maxillary first premolars and to study the effects of the above using three-dimensional scanned models and lateral cephalograms.Methods: A finite element model of maxillary dentition with alveolar bone, an acrylic splint on six anterior teeth, palatal implants, and short e-chain were produced to measure shifting when force was applied from three various levels. Thereafter, the finite element analysis findings were applied to 10 patients requiring fixed orthodontic treatment with first premolar extraction and fulfilling the inclusion criteria. Impressions were made and the rate of retraction was evaluated at 4-week intervals by superimposition of scanned models.Results: En-masse bodily retraction was seen when both canine hooks and palatal TAD was placed at 10 mm distance from the respective gingival margin. Clinically, subjects showed significant retraction at that level and statistically significant results in some cases. The maximum rate of retraction was seen in the first three months (average: 5.310 mm) with p-value <0.0001.Conclusion: Translational tooth movement was observed when line of force was at the level of the center of resistance.