- 期刊
阻生第三大臼齒在牙周病及治療的重要性：文獻回顧
The Significance of the Third Molars in Periodontal Therapy: A Review of the Literatures
摘要
在形成牙周炎的眾多貢獻因子（contributory factors）中，其中因第三大臼齒萌發方向異常或萌發不全，可能造成第二大臼齒遠心側形成牙周囊袋和周圍牙周骨頭吸收；或第二及第三大臼齒間因縫隙口腔清潔不良而好犯牙周病。阻生第三大臼齒最常見併發牙冠周圍炎。從文獻探討第三大臼齒的牙冠周圍炎病理破壞及細菌種類，得知和牙周炎形成過程的病理現象有某種程度相關。在治療阻生第三大臼齒，診所執業醫師和一般口腔外科醫師較常會考慮怎樣把阻生第三大臼齒完全拔除，但卻較少考慮在拔除阻生第三大臼齒的同時做一些措施，像遠心楔形手術（distal wedge），齒槽骨整形術（alveoloplasty），引導組織再生術（guided tissue regeneration）和牙周辦膜根向移動術（apically repositioned flap）等來預防第二大臼齒遠心端形成牙周炎，或同時替第二大臼齒治療深的牙周囊袋和去除其牙根表面的牙結石和牙菌斑。從本篇文獻回顧裡，智齒要拔除的時機有：（1）在25歲前，如果需要拔除則宜儘早拔掉，（2）當智齒產生病理性變化，（3）25歲以後，若智齒在骨頭中，則不一定要拔，產生病理性變化除外；若已露出骨頭外，除非要拿來當矯正的錨定（anchorage）或當牙橋的遠心支柱牙（abutment）否則一定要拔。如果埋伏齒已合併相鄰第二大臼齒之遠心側有牙周炎和骨頭破壞，必須在手術拔除第三大臼齒時做特殊翻辦設計和牙根整平術，或有合適的適應症時併用再生膜手術，則應可得到牙周囊袋減少及較佳的骨頭填滿（bone fill）效果。
並列摘要
One of many factors contributory to development of periodontitis is an unerupted or abnormally erupted third molar and it may cause deep pocket formation and bony resorption at the distal side of adjacent second molar. It is also prone to result in periodontitis due to interdental food impaction and uneasy cleaning between the third molar and second molar. The most common complication of the impacted molar is pericoronitis. Thorough literature review of pathological destruction and bacterial types related to pericoronitis of impacted third molars suggests that it has somewhat association with the initiation of periodontitis of adjacent molars. In the treatment of impacted third molar, dental practioner and oral surgeon more often think about how to extract the third molar completely, but rarely consider to add some procedures such as distal wedge, alveoloplasty, guided tissue regeneration, and apically repositioned flap etc., to prevent 2nd molar from developing periodontitis. The latter procedures can reduce its accompanying deep pocket, to remove plaque and calculus on its diseased root surface. In this review article, the indications of extracting impacted third molar are: (1) If impacted third molar needs to be removed before 25 years old, it should be performed as early as possible, (2) whenever the impacted third molar has associated pathological changes (3) If the third molar is embedded fully inside the bone, leave it alone when patient's age is greater than 25 years old. In case of partially exposed from alveolar bone, extraction is recommended except other uses such as orthodontic anchorage or distal abutment of crown and bridge. If impacted third molar was complicated by periodontitis and bony destruction of the 2nd molar, extraction must be performed in combination with either a periodontal flap design and root planning, or guided tissue regeneration to quantee more pocket reduction and hopeful greater bone fill.