根據實驗結果與統計分析發現，使用擠壓針加熱方法移除根管內馬來充填膠後出現根尖滲漏情形中，以垂直擠壓馬來膠封填方法(vertical compaction method)有較佳的結果，而且牙根釘柱準備時機在第7天的滲漏最少，因此建議應該在充填糊劑能完全硬化後再製備牙根釘柱空間比較佳。因此，在臨床上修造牙根釘柱時機建議必須於贋復牙冠齒質削磨前才開始準備，應有保持較佳的根尖封閉性的結果。惟目前臨床上仍有多種不同根管封填方法及材料，更有不同成份的充填糊劑(sealer)，彼此間是否在根尖封閉性上會有相當的理想結果，建議必須有更進一步的研究瞭解其適應情況，才會減少贋復治療時根尖封閉的結果。 70顆單根管牙齒(single canal)，經髓腔開口，工作長度量測後，使用手動不銹鋼根管銼針配合沖洗溶液作根管清創擴大修形至根尖直徑為0.40 mm及6.0%錐度後。使用隨機抽樣分組方式，分別用側方擠壓馬來膠充填方法(lateral compaction method)（30顆）、垂直擠壓馬來膠填方法(vertical compaction method)（30顆）兩種方法予以根管封填，另外10顆完全不封填（控制組）。根管封填完成後置放於攝氏370下保存，再分別於封填後l、3、7天，利用擠壓針加熱方式(heat plugger)將充填根管內齒冠部分馬來膠移除至剩餘約5.0厘米。隨後經2.0%甲基藍染料(methylene blue dye)浸泡7天後，再利用骨鑿(chisel)將牙齒縱裂為二。最後，使用立體放大顯微鏡(stereo-microscope)檢視染色劑滲漏之深度，分析在不同時間移除根管內以不同方法封填的馬來膠，其影響根尖封閉能力的不同結果。經過根管治療的牙齒因齒質過度破壞而需要接受固定牙冠贋復(crown restoration)。牙冠之製作前期常需要鑄製牙根釘柱(post)，以增加強度(strength)與固持力(retention)。在牙根釘柱空間準備的過程，需要移除已封填在根管內齒冠部分的馬來膠(gutta-percha)材料，可能會造成根尖封填材料之鬆脫而影響牙根尖之緊密封閉能力(sealing ability)，將導致根管可能有再感染的途徑與機會。本實驗目的在探討牙根釘柱準備之時機與不同根管封填方法如側方擠壓或垂直擠壓方法中，其是否會有影響根尖封閉能力的可能。

Endodontically treated teeth usually required intracanal posts in order to reinforce the strength of the tooth structure and the retention of the crown. The purpose of this study is to evaluate the effect of different timing and methods that post space preparation has on the apical seal after the root canal obturated with different root canal filling methods. A total of 100 single root canal extracted teeth had already been collected and prepared for the root canal treatment using step-back technique. They were extracted because of severe periodontal problem and orthodontic reason. The apex was maturely formation and the apical constriction had not been destructed during the extraction procedure. All the samples were accessed with a #4 round diamond bur through the occlusal surface as same as the principles that Cohen et al. described. The access cavity was prepared carefully to prevent the remaining of the pulp horn and overreduction the tooth structure that increased the surface of dye penetration test. All the prepared teeth are stored in the physiological saline and prepared for root canal obturation with GP and calcium hydroxide root canal filling materials using several techniques including lateral compaction method, vertical compaction method, and thermoplasticized warm GP. Thereafter, the apical 5.0 of the filling materials will be left after the coronal portion removed with hot plugger within 1, 3, and 7 days after root canal obturation. Finally 2.0% methylene blue dye will be used to demonstrate the microleakage of the apical seal after the above managements. The results will be measured, recored, and statistically analyzed.