Paiboon Techalertpaisarn

Chulalongkorn University, Krung Thep, Bangkok, Thailand

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Publications (4)3.83 Total impact

  • Paiboon Techalertpaisarn · Antheunis Versluis
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    ABSTRACT: Objective: To investigate the effect of vertical steps on a T-loop force system at three interbracket distances (IBDs) and their association with V-bends. Materials and methods: Loop response during simulated loop pulling was determined for 18 T-loop configurations (6-, 9-, and 12-mm IBD with a 2.5-mm canine bracket (CB) end and 0- (plain), 0.5-, or 1-mm vertical step). Loop length-by-height was 8 × 8 or 10 × 10 mm. Horizontal load/deflection, vertical force (Fy), and moment-to-force (M/F) ratios at loop ends were determined for 100-g and 200-g activation by finite element analysis. Results: Plain, 12-mm IBD T-loops showed similar force and moment responses as off-centered V-bends (greater moment close to V-bend) without change in moment direction at the premolar bracket (PB) end; plain, 6-mm IBD T-loop responses were similar to those of centered V-bends (equal, opposing moments at each end). Adding vertical steps to the T-loops raised the M/F ratio at the PB ends enough to produce root movement, while lowering the M/F ratios at the CB ends. Increasing the step bends for shorter IBDs increased Fys and caused rapid changes in M/F ratios. Unlike plain T-loops, increasing activation in stepped T-loops caused substantial variations in M/F ratios and in amount and direction of Fys. Conclusions: Step bends can dramatically change the force system. Stepped T-loops display combined effects of V-bends and step bends.
    No preview · Article · Aug 2015 · The Angle Orthodontist
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    Paiboon Techalertpaisarn · Antheunis Versluis
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    ABSTRACT: Closing loops are used in orthodontics to apply forces on teeth and cause them to move in a desired direction. The objective of this study was to investigate the effect of loop geometry and position on loop properties. Using finite element analysis, loop response was simulated for three closing loop designs (vertical, T-, and L-loop) at thirteen loop positions. Loop length and height were 14 and 10-mm, respectively. Loop properties (horizontal load/deflection, vertical force, and moment-to-force ratio M/F) on both ends were measured at 100 and 200 g force activation or when moving both ends 2-mm together. It was found that the pattern of changes in loop properties with loop position was similar for the vertical and T-loop. They reached their maximum M/F-ratios of 5.5 and 7.3, respectively, at the ends closest to 1/5 or 4/5 off-center loop positions. M/F-direction at an end changed when the loop was about 2/3 away (vertical loop) or 4/5 (T-loop). The L-loop behaved differently, reaching its maximum 8.7 M/F-ratio (200 g activation) when centered. M/F-direction only changed at the opposite end of the L-loop direction, and occurred when the loop was centered. This study showed that loop properties depended on loop shape, position and activation. The way properties changed with loop position depended on their designs. Clinicians should consider the specific characteristics of each loop configuration for desired tooth movements.
    Preview · Article · May 2013 · Oral Science International
  • Paiboon Techalertpaisarn · Antheunis Versluis
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    ABSTRACT: The objective of this research was to investigate the mechanical properties at both sides of Opus closing loops by analyzing the effects of loop shape, loop position, coil position, and tipping of the vertical legs. Opus loops were compared with L-loops (with and without a coil) and a T-loop by using finite element analysis. Both upright and tipped vertical loop legs (70°) were tested. Loop response to loop pulling was simulated at 5 loop positions for a 12-mm interbracket distance and 10-mm loop lengths and heights. Three-dimensional models of the closing loops were created by using beam elements with stainless steel properties. The L-loops and Opus loops were directed toward the anterior side. Loop properties (horizontal load/deflection, vertical force, and moment-to-force ratio) at both loop ends were recorded at activation forces of 100 and 200 g. Upright Opus loops and L-loops showed the highest moment-to-force ratios (8.5-9.3) on the canine bracket when the loop was centered. The Opus loops and L-loops with tipped vertical legs and the T-loop had slightly lower moment-to-force ratios (7.8-8.5), with the maximum values occurring when the loop was placed close to the canine bracket end. Upright L-loops showed the highest moment-to-force ratios on canine brackets, whereas backward tipping of the vertical legs shifted mechanical properties closer to those of a T-loop. Loop properties varied with loop configuration and position. Clinicians should understand the specific characteristics of each loop configuration to most effectively exploit them for the desired tooth movements.
    No preview · Article · May 2013 · American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics
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    ABSTRACT: Abstract Objective: To determine the effect of labiolingual inclination of a maxillary central incisor on the magnitude and distribution of stresses within the periodontal space. Materials and Methods: Five three-dimensional finite element models of a right maxillary central incisor were created with 0°, 10°, 20°, 30°, and 40° inclination. Each incisor model was subjected to a 1 N lingual-directed force and 6-12 N·mm countertipping moment on the labial surface. The stress level within the periodontal ligament was calculated in terms of maximum principal stresses. Results: With increased inclination, compressive stresses tended to increase whereas tensile stresses tended to decrease. The location where compressive stress was prevalent changed from the midroot area to the apical area on the lingual side, while the area where tensile stresses were predominant changed from the midroot area to the cervical area on the labial side. Conclusion: There are more compressive stresses concentrated at the apex of incisors with a high degree of inclination than in incisors that are more upright. This may be associated with the higher clinical incidence of apical root resorption found in inclined maxillary central incisors.
    No preview · Article · Feb 2012 · The Angle Orthodontist