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"Di Indonesia, pengembangan produksi braket ortodonti dalam negeri sedang dikerjakan dan dibutuhkan studi lebih lanjut untuk mengetahui desain rumus bangun geometri dasar braket yang memiliki retensi terbaik. Braket ortodonti metal dapat melekat pada gigi mengandalkan retensi mekanis pada dasar braket. Analisis finite element suatu analisis dengan menggunakan model tiga dimensi untuk mempelajari dan menilai distribusi stress yang terjadi akibat aplikasi gaya geser dengan besaran dan arah tertentu. Letak konsentrasi stress yang besar diprediksi berisiko terjadi deformitas atau kegagalan. Penelitian ini menggunakan tiga jenis braket ortodonti metal insisif pertama rahang atas dengan tipe dasar braket non mesh yang ada di pasaran. Pembentukan model tiga dimensi berupa gigi insisif pertama rahang atas dengan blok tulang, tiga tipe braket, dan adhesif ortodonti. Proses simulasi dengan aplikasi gaya geser mesio-distal dan serviko-insisal sebesar 1 N. Hasil analisis finite element menunjukkan adanya perbedaan distribusi stress dari gaya geser mesio-distal dan serviko-insisal pada tiga jenis rumus bangun dasar braket di permukaan dasar braket, lapisan adhesif ortodonti, permukaan email, dan jaringan periodontal.

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In Indonesia, the development of domestic production of orthodontic brackets is underway and further studies are needed to find out the design of the basic bracket geometry formula that has the best retention. Metal orthodontic bracket can adhere to teeth surface by relying on mechanical retention in the base of the brackets. Finite element analysis is an analysis using three dimensional model to asses the stress distribution that occurs due to application of shear forces with certain magnitude and direction. The stress concentration and the distribution can be predicted and assumed to be the potential risk of deformity or failure. This study used three types of metal orthodontic brackets which available on the market. Three maxillary first incisors brackets with different bases, maxillary right incisor with periodontal tissue ,bone block, and orthodontic adhesive were construct using a software as a three dimensional model. The model were simulated with the application of shear stress mesio-distal and cervical- incisal one Newton each. Finite element analysis showed there are difference in stress distribution of mesio-distal and cervical-incisal shear stress on three types of different geometry of bracket base on the bracket base surface, orthodontic adhesive layer, enamel surface, and periodontal tissue."

"Latar Belakang: Ekspresi penuh dari preskripsi torque bracket dipengaruhi oleh faktor yang berkaitan dengan bracket, kawat, torque play, dan faktor klinis. Hingga saat ini belum ada penelitian yang membandingkan kemampuan ekspresi torque antara berbagai ukuran kawat pada penggunaan bracket passive self-ligating (PSL) dan konvensional melalui simulasi finite element, serta menganalisis interaksi dari faktor-faktor tersebut, sekaligus memberikan gambaran pergerakan gigi dan respon jaringan periodontal. Penelitian ini bertujuan untuk mengukur besar torque play dan menganalisis pola perpindahan inisial gigi, serta distribusi stress antara berbagai ukuran kawat pada penggunaan bracket PSL dan konvensional melalui simulasi finite element. Metode: Model 3D dikonstruksi dengan skenario kasus yang membutuhkan pencabutan premolar pertama dan retraksi masse gigi anterior maksila, menggunakan penjangkaran temporary anchorage device dan gaya retraksi 150 g. Simulasi finite element dilakukan untuk mengukur torque play antara penggunaan kawat stainless steel 0.016 x 0.022", 0.017 x 0.025" dan 0.019 x 0.025", serta mengukur perpindahan inisial pada tepi insisal dan apeks akar insisif sentral maksila, serta distribusi stress pada PDL dan tulang alveolar antara penggunaan ketiga ukuran kawat pada kedua jenis bracket. Hasil: Pada penggunaan kawat 0.019 x 0.025", 0.017 x 0.025", dan 0.016 x 0.022" didapatkan torque play sebesar 7.6º, 11.6º, dan 18.7º untuk bracket PSL, dan 9.5º, 14º, dan 18º untuk bracket konvensional. Retraksi dan ekstrusi tepi insisal terbesar dihasilkan oleh kawat 0.016 x 0.022", sedangkan perpindahan palatal dari apeks terbesar dihasilkan oleh kawat 0.019 x 0.025". Konsentrasi stress terbesar terletak pada area 1/3 servikal pada sisi palatal dan 1/3 apikal pada sisi labial, yang menunjukkan pola perpindahan uprighting atau lingual crown tipping. Penggunaan kawat dengan diameter terbesar dan bracket konvensional menghasilkan stress terbesar pula.Kesimpulan: Torque play antara kawat dan bracket berbanding terbalik dengan ukuran kawat. Besarnya lingual crown tipping berbanding lurus terhadap torque play antara kawat dan bracket, dan dikonfirmasi oleh pola distribusi stress di PDL dan tulang alveolar. Kendali torque yang paling baik didapatkan oleh penggunaan kawat stainless steel 0.019 x 0.025". Perbedaan metode ligasi dan geometri bracket konvensional dan PSL kemungkinan menyebabkan adanya perbedaan besar moment yang dihasilkan.

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Introduction: The full expression of torque prescription of a bracket is influenced by bracket-related factors, wire-related factors, torque play and clinical factors. Finite element analysis (FEA) could be utilized to deepen our understanding and study the interaction between these factors, as well as to produce a simulation of the predicted tooth movement and tissue response. This study aims to measure the amount of torque play, and to analyse the pattern of initial tooth displacement, among different wire sizes and between passive self-ligating and conventional brackets using FEA.

Methods: A 3D model was constructed simulating a case which required first premolar extractions and en masse anterior retraction using temporary anchorage device and 150 g of retraction force on each side. Finite element simulation was performed to measure torque play, to investigate the pattern of initial tooth displacement at the incisal tip and of apex of the central maxillary incisor, as well as to analyse the pattern of stress distribution at the periodontal ligament (PDL) and alveolar bone, among different stainless steel wire diameters (0.016 x 0.022", 0.017 x 0.025" and 0.019 x 0.025") and between PSL and conventional brackets.

Results: The use of 0.019 x 0.025", 0.017 x 0.025", and 0.016 x 0.022" wires on PSL brackets produced a torque play of 7.6º, 11.6º, and 18.7º, respectively. While the use of the same wire sizes on conventional brackets produced a play of 9.5º, 14º, dan 18º, respectively. The use of 0.016 x 0.022 produced the farthest retraction and extrusion of the incisal tip. However, the greatest apex retraction was produced when 0.019 x 0.025" was used. The largest stress concentration was observed at the 1/3 cervical area on the palatal side and at the 1/3 apical area on the labial side. This shows that there is a pattern of uprighting or lingual crown tipping of the teeth. The use of 0.019 x 0.025" and conventional brackets yielded the greatest amount of stress on the PDL and alveolar bone.

Conclusion: The degree of torque play between wire and bracket was inversely proportional to the wire size, and the amount of lingual crown tipping was directly proportional to the degree of play. This pattern of tooth movement was confirmed by the pattern of stress distribution on the PDL and alveolar bone. Torque expression was better achieved using the 0.019 x 0.025" wire. Differences in the geometry and method of ligation between PSL and conventional brackets possibly generated different force magnitudes."