- 期刊
快速上顎擴張器對上顎位置之影響－動物實驗
Maxillary Displacement after Rapid Maxillary Expansions-An Animal Study
摘要
文獻回顧發現，傳統的快速上顎擴張器，擴張後並不會造成一致性的上顎位移模式。探究快速上顎擴張過程中，影響上顎位移的因素，除顱顏骨骼的型態及構造等解剖因素外，快速上顎擴張器本身的設計，亦可能具有決定性的影響。本研究目的即為分析新型雙軸式快速上顎擴張器所造成的上顎擴張型態，並評估其對上顎位移的影響。實驗對象為12隻同品系一歲貓隻，隨機平分成Hyrax組與雙軸組，兩組均施予1mm/天，共計7天的快速上顎擴張，以測量擴張前後頦下測顱X光片上牙齒及金屬植體參考點位置變化的方式，分析二種擴張器的上顎擴張型態及位移模式，並以無母數統計檢定兩組參考點橫向與矢向移動量差異。實驗結果發現二種擴張器均能顯著地將貓隻上顎擴張並前置，但兩者造成的上顎橫向與矢向位移型態與量明顯不同。Hyrax組呈現上顎前部與後部擴張量約略相等、上顎前部與後部前置量約略相等的位移模式；雙軸組則呈現上顎前部大於後部擴張量、上顎前部大於後部前置量的位移模式。但雙軸組上顎前部擴張量顯著大於Hyrax組(3.42±0.86 vs. 1.70±0.92 mm, p=0.012)，且雙軸組上顎前部前置量均顯著大於Hyrax組(3.54±0.89 vs. 1.62±0.96 mm, p=0.010)。本動物實驗證實，雙軸式快速上顎擴張器的裝置作用模式，相較於傳統Hyrax式快速上顎擴張器，雙軸式快速上顎擴張器更能有效地將上顎前置。
並列摘要
One of the contemporary techniques for maxillary protraction is combined use of hyrax-typed rapid maxillary expander and face mask. It is hypothesized that maxillary expansion disarticulates maxilla and makes maxillary protraction easier for facemask. However, the possible backward displacement of maxilla after expansion may reduce its effects. To overcome these disadvantages, we modified the hyrax-typed expander into a double-hinged configuration that is postulated to have better anterior displacement of maxilla. The purpose of this animal study was to evaluate the effects of double-hinged rapid maxillary expander on the maxillary displacement. Twelve inbred 12-month-old cats were used and divided into two groups, each included six cats. The two groups were assigned respectively for comparison the patterns of maxillary displacement between the Hyrax and double-hinged expanders underwent seven days of expansion and 1 mm per day. The maxillary displacements in sagittal and transverse planes were analyzed by using amalgam metallic implants and submental cephalograms. The inter-group changes were evaluated with Mann-Whitney U test. The maxilla showed anterior displacement in both the hyrax and the double-hinged expander groups. However, the amount of anterior displacement was significantly greater in the double-hinged expander groups (3.54±0.89 vs. 1.62±0.96 mm, p=0.010). The expansion patterns between the two groups were also different. The hyrax expander separated two maxillary halves in a more parallel way. The double-hinged expander expanded anterior part of maxilla more than its posterior part. Both results reflected the differences between expansion mechanics of the two type expanders. The double-hinged expander could displaced cats’ maxilla forward effectively after expansion.