Effects of dental arch size variation on orthodontic forces delivered by preformed Ni-Ti archwires

2021 ◽  
pp. 1-9
Author(s):  
Akihiko Tachi ◽  
Naomi Saze ◽  
Keisuke Tochigi ◽  
Kazuhito Arai
2004 ◽  
Vol 49 (12) ◽  
pp. 1015-1024 ◽  
Author(s):  
Shosei Eguchi ◽  
Grant C. Townsend ◽  
Lindsay C. Richards ◽  
Toby Hughes ◽  
Kazutaka Kasai

2015 ◽  
Vol 85 (6) ◽  
pp. 1009-1014 ◽  
Author(s):  
Rhita C. Almeida ◽  
Jonas Capelli ◽  
Ricardo P. Teles

ABSTRACT Objective:  To examine levels of matrix metalloproteinases (MMPs)-1, -2, -3, -7, -8, -12, and -13 in the gingival crevicular fluid (GCF) of periodontally compromised teeth at different time points during orthodontic movement. Materials and Methods:  Ten controlled periodontitis subjects were submitted to orthodontic treatment. One dental arch was subjected to orthodontic movement, and teeth in the opposite arch were used as controls. GCF samples were collected from the lingual sites of two movement and two control incisors 1 week before orthodontic activation (−7 d), immediately after orthodontic activation, and after 1 hour, 24 hours, and 7, 14, and 21 days. Multiplexed bead immunoassay was used to measure MMPs in GCF. Data were analyzed using Friedman and Wilcoxon statistical tests. Results:  The only significant change found over time was in the levels of MMP-1 in the movement group (P < .05). When the two groups were compared after activation, the only statistically significant difference found was in levels of MMP-12 24 hours after activation (P < .05). Conclusions:  Our findings suggested that the orthodontic movement of periodontally compromised teeth without active pockets did not result in significant changes in the GCF levels of MMPs.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Akihiko Tachi ◽  
Keisuke Tochigi ◽  
Naomi Saze ◽  
Kazuhito Arai

Abstract Background Although preformed archwires with a variety of arch forms are currently commercially available, the effects of variation in the shape of these archwires on the orthodontic force at each tooth are not well understood. Therefore, we evaluated the forces delivered by various types of commercially available preformed nickel–titanium alloy (NiTi) archwires in a simulated mandibular dental arch. Methods Sixty-three types of 0.019 × 0.025-inch preformed NiTi archwires from 15 manufactures were selected for analysis. The intercanine width (ICW) and intermolar width (IMW) of each archwire were measured at the mean canine and first molar depths of 30 untreated subjects with normal occlusions. Each archwire was placed in a multi-sensor measurement system simulating the mandibular dental arch of subjects with normal occlusions, and orthodontic forces in the facial-lingual direction at the central incisors, canines, and first molars were measured. Correlations between the ICW, IMW, and ICW/IMW ratio of archwires and the delivered forces were analyzed. The archwires were classified into the following four groups according to the ICW and IMW: Control group, ICW and IMW are within the means ± standard deviations of the normal ranges; Ovoid group, narrow ICW and IMW; Tapered group, narrow ICW; and Square group, narrow IMW. The forces were compared among these groups for each tooth. Results Significant correlations between the measured archwire width and force to each tooth were found, except between IMW and forces at the central incisors and canines. Significant differences in the forces were found among all groups, except between the Ovoid and Tapered groups at all teeth and between the Ovoid/Tapered and Control groups at the first molar. Significantly greater orthodontic forces in the facial direction were delivered at the central incisors by the archwires in the Ovoid and Tapered groups when compared with the archwires in the other groups. Conclusion These findings suggest that there is a possible risk of a clinically significant level of unfavorable orthodontic force being delivered to the mandibular incisors in labial inclination when using a preformed archwire with an ICW that is narrower than the dental arch.


2009 ◽  
Vol 8 (1) ◽  
pp. 48
Author(s):  
Harun Achmad

Delayed eruption is one of dental eruption deviation characterized by delay of dentaleruption. Delayed eruption can be caused by local factor such as impacted tooth. Thiscan be managed surgically and then orthodontically brought into the dental arch. Aneleven years old girl came to the dental clinic specialist of FKG-UNPAD Bandung,with the chief complaint of having non-erupted upper left permanent central incisor,without retention of 61. Other 3 upper incisor, 11, 22, 12 have erupted normally.Panoramic examination showed impacted 11 in the alveolar bone with complete apexformation. Following the cephalometric and model analysis, the fixed orthodonticappliances were placed, followed by surgical exposure to open the impacted area thenplaced an orthodontic bracket with an attached chain to apply orthodontic forces onthe tooth to aid its movement into the line of occlusion. After 6 months treatment,patient’s esthetics and masticatory function were obtain, marked by normal position of21 in the arch.


2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.


Author(s):  
Kohinur Akther ◽  
Md Zakir Hossain

Aim: Objectives: To analyze variations in dental arch width in relation to oral habits.   Materials and Methods : Cross sectional  study was carried out Department of Orthodontics & Dentofacial Orthopedics of Dhaka Dental College & Hospital, Dhaka with a total number of 600 primary school children of 3-6 years ages of Bangladeshi population. Results: This study was a cross sectional study conducted among the 600 children with 3-6 years old prima- ry school children of Bangladeshi population. According to present study, bottle feeding causes significant reduction in maxillary intercanine width and mouth breathers show significant reduction of both arches. Conclusion: It was observed that the children who had used a bottle had a significant reduction in maxillary intercanine width. Breathing through mouth appeared to be associated with a reduction in the size of both arches. This was more significant in the maxillary intercanine , mandibular  intercanine and mandibular molar widths. Therefore to prevent malocclusions, the public should be informed of the harm caused by certain oral habits, the benefits of breast-feeding, and the need to correct bad habits at early life. Ban J Orthod & Dentofac Orthop, April 2016; Vol-7 (1-2), P.6-11


2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>


DENTA ◽  
2017 ◽  
Vol 11 (1) ◽  
pp. 80
Author(s):  
Chaterina Diyah Nanik K ◽  
Anindita Apsari

<p><strong><em>Background:</em></strong><em> One of the most common inflammation disease in the oral cavity for the past few years is the aggressive form of periodontitis. Common signs of aggressive periodontitis is the mobility of teeth especially in incisive and first molars, and occuring mostly in young patient. Young patients whose losing her anterior teeth, are a real challenge for dentist and prosthodontist. Prosthodontist need to consider both functional and esthetic aspects. <strong>Objective:</strong> Rehabilitation of young adult patient with aggressive periodontitis by an interdisciplinary approach of orthodontist and prosthodontist. <strong>Case Description:</strong> A young woman, suffered from aggressive periodontitis with major complain of her teeth mobility, especially incisive and first molar in mandible. She had undergone periodontal treatment, but the result was failed. The anterior teeth in mandible need to be extracted, therefore patient wished not to be in edentulous state. As preliminary treatment, we choose immediate denture to replace the anterior mandible teeth. We faced difficulties in mandible, because her right canine weren’t in the proper dental arch. So we asked orthodontist to place fixed orthodontics in mandible, to get the canine back in the proper arch. We’ve chosen orthodontic treatment,because we didn’t want to extract the canine teeth. We evaluated in six months and after the canine back in the proper arch, we proceed to long span bridge in mandible as our definitive treatment. <strong>Conclusion:</strong> By not extracting the canine teeth, we got some advantages, especially patient psychically was happier with her own teeth. The collaboration with another dentistry field, provides us better treatment for patient. After treatment, patient had no complaints and was happy with her new smile.</em></p><p><strong><em>Keywords:</em></strong><em>  Prosthodontic rehabilitation, aggressive periodontitis, orthodontic treatment, esthetic</em><em>.</em></p><strong><em>Correspondence:</em></strong><em> Chaterina Diyah Nanik. K; Department of Prostodontitics, Faculty of Dentistry, Hang Tuah University, Arif Rahman Hakim 150, Surabaya; Phone 031-5912191, Email: </em><a href="mailto:[email protected]"><em>[email protected]</em></a>


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