牙齒如果受到過重的咬合力量傷害，便會出現裂痕甚至於發生齒質斷裂的結果。牙齒斷裂會因侵犯的範圍及嚴重程度會出現不一樣的裂齒症候（cracked tooth syndrome）。目前臨床上有裂齒症的患者通常都以被動性的治療方式，建議病患套上矯正用之不鏽鋼矯正環套以避免牙齒裂痕有延伸擴大的可能，後續再以放射線照像以判斷牙齒的損傷及侵犯的程度。過往的文獻中，並沒有積極的預防及探討不鏽鋼矯正環套其有效保護牙齒免受不當咬合力的傷害的能力。因此沒有實證依據充分解釋一個具有對裂齒症的患齒的最佳處置方式，本研究目的藉由積體電路之超微小型應變規測量力學分布的差異性來探討矯正不鏽
鋼矯正環套是否會改變發生裂齒症的牙齒其咬合力量的傳導及分佈。期以獲得更有利於臨床治療裝置的
使用證據。
蒐集因矯正治療需要拔除的小臼齒約10顆為樣本儲存於麝香酚溶液（Thymol solution）中並隨機分組分為二組（每組5顆），第一組是正常的牙齒，第二組以人工製造出裂痕的牙齒。兩組牙齒樣本都包埋於長寬高分別為2.5公分×2.5公分×4公分的環氧樹脂塊中，並分別圍上不銹鋼矯正環套。在咬合面選擇三個測試點分別在距裂痕之頰側0.2公分處（A點），距裂痕直線往前0.2公分延伸位置（B點），及距裂痕舌側0.2公分處（C點）貼上超微小型應變規（strain gauge）進行應變測試。咬合力量應變測量主要使用NI Compack Daq（Compack Daq, National Instrument, USA）應變量測系統內之資料擷取系統，並配合其應變規的模組，量測正常牙齒與裂痕牙齒之周圍三個測量點的應變值變化。夾具內牙齒樣本除了可固定於實驗模型之底部外，亦可以旋轉，以測量牙冠在承受不同角度及方向的咬合力改變。（舉例來說：0度施力於牙齒頰側咬頭處之垂直咬合力與30度施力於牙齒斜面舌側咬頭之側方咬合力。）
兩組牙齒樣本完成保護裝置樣本的應變力測試後，再將環帶使用鑽針磨耗移除，並避免損傷應變規，
再進行沒有環帶保護之樣本的應變力測試，相互比較有沒有環帶保護之差異。兩組牙齒樣本在是否使用環帶裝置與不同施力狀態下之受力分布測量結果使用paired-t test做統計分析，p值低於0.05即認為具有統計差異。 ( J. Family Dent. 8(2): 16-23, 2013 )

Infarction or crack line might be happened if overloading or heavy occlusal force are applied. Cracked teeth have been problematic for more than three decades because of its complexity. This dental condition has a set of signs and symptoms that occur together as complex, it has been referred to as cracked tooth syndrome.
Recently, the cracked tooth is treated by stabilizing the cracked and preventing its expansion with both circumferential fixation with orthodontic band device and occlusal protection during mastication. Periodic radiography examinations are recommended to determine the prognosis of the preventive treatment. Many treatment options including occlusal adjustement, banding and operative procedures are ineffective treatment for cracked tooth syndrome because they do not protect the cracked tooth from occlusal force during chewing.Many studies in the past did not explain and conclude the effective clinical treatment for cracked tooth.
The purpose of this study is to investigate the relationship of occlusal force distribution of cracked tooth treated with stainless steel orthodontic band using strain gauge analysis.
A total of 10 extracted bicuspid were collected and stored in thymol solution to prevent the damage of hard tissues. The teeth were extracted because of an orthodontic reason. All samples were randomized divided into two groups (5 teeth each) and will then fractured with a chisel along the central groove after grooving with a No. 2 diamond bur. The specimens were embedded into epoxy resin of 2.5cm x 2.5cm x 4.0cm diameter Stainless steel orthodontic band was used to protect the fractured tooth specimen that was
generated with a surgical chisel. The force distribution sensors will be attached at three equal distance points at 2.0mm far from the buccal and palatal side of fracture line before and after the protection devices
were used. The occlusal force distribution of tooth samples proctected with orthodontic band between two different loading direction were tested with a strain gauge that was connected with NI Compack Daq system. All the data were recorded for statistically analysis. ( J. Family Dent. 8(2): 16-23, 2013 )