MTA與DFC對於乳牙冠髓切除術治療療效評估之臨床試驗研究

Abstract

在乳牙因蛀牙產生牙髓發炎情況時，冠髓切除術（pulpotomy）是臨床上最常使用的治療方式。而五倍稀釋的Formocresol（diluted FC，DFC）是目前最廣泛應用於乳牙冠髓治療的材料，但由於FC化學成分的致癌性以及造成牙根內吸收併發症等問題，使其在臨床治療使用上產生疑慮。MTA為1993年研發的生醫材料，具有優異的生物相容性及良好的封閉能力，於恆牙活髓治療應用時可以促進組織癒合及誘導硬組織的形成，被認為具有潛力取代FC應用於乳牙冠髓切除術。因此，本研究應用臨床隨機試驗的研究方法，比較使用MTA和DFC在人類乳臼齒冠髓切除術的臨床與放射學治療結果，評估MTA是否可以取代FC成為人類乳臼齒進行冠髓切除術的常規治療術式。本研究招募自2009年12月至2010年12月期間，於臺灣大學附設醫院兒童牙科進行治療，年齡介於2.8至6.8歲之42位健康孩童，共94顆乳臼齒，以隨機分配使用灰色MTA（Grey MTA，GMTA）或DFC進行冠髓切除術；所有的治療步驟與結果分析方法均遵循臨床試驗研究倫理的規範。研究結果顯示術後3個月追蹤回診率為93％，6個月追蹤回診率為82％。所有的牙齒在回診時均未出現臨床病理症狀，兩組的臨床治療成功率為100%。在3個月追蹤時， GMTA組的放射學成功率為98%，DFC組為85%，其差異具有統計上的意義（p=0.045）；而6個月追蹤時，兩組的放射學成功率無統計顯著差異（p=0.24），GMTA組為95%，DFC組為86%。在不同回診期間，兩組大部份樣本的放射學影像沒有明顯變化（3個月：GMTA為51%，DFC為67%；6個月；GMTA為43%，DFC為49%），且兩組間也無顯著差異；而出現牙本質屏障影像的樣本多為GMTA組，兩組間的差異具有統計意義（p < 0.01）；至於根管鈣化和牙根外吸收的情形在兩個治療組別都有表現，兩組間無顯著差異；另外，DFC組約有15%的樣本出現牙根內吸收與牙根外吸收等放射線病理影像，略高於GMTA組（<5%），但無顯著差異。根據多變項名義邏輯回歸模型分析可能的結果預測因子變項與放射學評估分數間的關係結果顯示，受試者的性別、年齡、牙齒的左右位置、乳臼齒的種類以及受試者的合作度等變項並不會影響放射學評估結果，而所使用的治療材料、牙弓位置、與操作者則對放射學評估分數有所影響。而使用類別邏輯回歸模型分析治療材料與放射學評估分數之間的關係，結果顯示無論在3個月或6個月回診時，與DFC組相比較，GMTA組有較高的機會出現較低的放射學評估分數，其勝算比在3個月為3.81（p= 0.003），6個月為3.40（p=0.006），意即GMTA組有較高的機會出現較理想的放射學預後。綜合本研究結果，雖然使用GMTA與DFC進行乳牙冠髓切除術在臨床成功率表現沒有顯著差異，但再放射學成功率與放射學影像變化方面，則可發現GMAT組明顯優於DFC組。因此GMTA應具有潛力取代DFC成為乳臼齒冠髓治療的材料，不過此一論點仍需更多樣本的臨床試驗與更長的追蹤觀察結果來加以佐證。

Pulpotomy is the most common treatment used for the carious primary teeth without radicular pulp involvement and formocresol (FC) is the most widely used medicament for this treatment. However, there are concerns associated with this medicament, primarily the carcinogenicity of the chemical and internal resorption of the treated tooth. Alternative pulp therapies have been investigated but none have been adopted as the current standard of care to replace FC. Recently, Mineral Trioxide Aggregate (MTA) has been reported as a potential material for pulp therapy of primary teeth because of its good sealing ability, excellent biocompatibility and the ability to actively promote hard tissue formation in vital pulp therapy of permanent teeth. The purpose of this study is prospectively assess the clinical and radiographic outcomes between gray MTA (GMTA) and DFC (dilute 20% Formocresol (DFC)) in pulpotomized human primary molars and evaluate if GMTA is a suitable replacement for FC in the pulpotomy of human primary molar teeth. To assess this goal, 94 primary molars from 2.5 to 6.8 year-old patients of Pediatric Dental Department of National Taiwan University Hospital were randomly assigned to GMTA group or DFC group. The recall rates at 3- and 6-month follow up were 93% and 82%, respectively. None of the treated teeth showed the signs of clinical failure within the follow-up periods. Clinical success was 100% in the both group. The radiographic success rate of GMTA group (98%) is significant higher than DFC (86%) group at 3-month follow-up (p=0.045). At 6-month follow-up, GMTA (95%) group showed a higher radiographic success than DFC (86%), but with no significant difference ( p=0.24). In both groups, most of treated teeth demonstrated no radopgraphic change either at 3-month or 6-month follow-up. More GMTA-treated teeth presented dentin bridge radiographically than DFC-treated teeth, and this difference between the two groups was statistically significant (p<0.05). Pulp canal obliteration and external root resorption were also observed in the both group. Internal root resoption without perforation or with perforation were only found in DFC group. Using the multinomial logistic model analysis, the investigated factors, “treatment material”, “arch type”, and “operator”, were found to influence the outcome of radiographic scores significantly (p<0.05). The analysis of ordinal logistic regression model showed that the GMTA-treated teeth were more likely to have lower scores than the DFC-treated teeth. The odds ratios of GMTA/DFC for lower to higher scores at 3-month follow-up and 6-month follow-up were 3.8 (p=0.003) and 3.4 (p=0.006), respectively. These results indicated that the GMTA pulpotomy revealed more favorable radiographic prognosis than the DFC pulpotomy. In conclusion, clinical success rate in both groups of GMTA and DFC was 100%, but statistically significant higher radiographic success and more favorable radiographic changes were found in GMTA group. Based on the results of this study, GMTA appears to be a potential replacement for FC as a pulpotomy agent in primary dentition. The further randomized clinical study with lager sample size and longer follow-up periods is needed to prove this point of view.