遠心位移的下顎第二小臼齒牙胚－案例報告

Distal Displacement of Lower Second Premolar Tooth Germs-Two Cases of Reports

謝宛君(Wan-Chun Hsieh) ； 王姻麟(Yin-Lin Wang) ； 張曉華(Hsiao-Hua Chang) ； 黃桂芬(Guay-Fen Huang) ； 郭敏光(Ming-Kuang Guo)

《臺灣兒童牙醫學雜誌》 18卷3期 (2018/09) Pp. 91-95

https://doi.org/10.6319/TJPD.201809_18(3).0002

摘要

下顎第二小臼齒在發育上是高度變異的，此外，下顎第二小臼齒是排序第三容易阻生的牙齒。下顎第二小臼齒牙胚遠端移位是一種罕見的臨床病症。在這個病例報告中，我們提出了兩例關於下顎第二小臼齒牙胚遠端移位（異位）並與第一大臼齒牙胚重疊或接近的病例。第一例是一名健康的3歲3個月大的女孩。她來到兒童牙科門診主訴是治療多顆無症狀的齲齒。治療完全口齲齒後，意外在根尖X光片中發現下顎雙側第二小臼齒牙胚遠端移位，並與第一大臼齒牙胚重疊。沒有臨床症狀和不適，透過影像學檢查定期追蹤。第二例是4歲6個月大的無全身性疾病的男孩，由於左下後方腫脹和膿腫而來到兒童牙科門診求診。透過馬來膠針循跡（tracing）和環口全景Ｘ光片檢查，我們發現左下第二小臼齒牙胚的遠端移位，其位置位於第二乳臼齒牙根和第一大臼齒牙胚之間。經抗生素治療一週後臨床症狀好轉，至今未見復發。由於這兩個病例還在乳牙齒列時期，所以我們將繼續追蹤下顎第一大臼齒的萌發狀況和第二小臼齒牙胚的位置。將來如果影響到第一大臼齒的萌發則會考慮拔牙處理和矯正治療。

關鍵字

恆齒第一大臼齒牙胚 ； 下顎第二小臼齒牙胚遠端移位 ； 乳牙齒列

並列摘要

The mandibular second premolar is highly variable developmentally. In addition, mandibular second premolar is found to be the ranked third of most frequently impacted tooth. Lower second premolar tooth germ distal displacement is a rare condition. In this case report, we present two cases about lower second premolar tooth germs distal displacement (ectopic position) and overlap or close to first molar tooth germs. The first case was a 3-year-3-month-old girl without history of systemic diseases. She visited our pediatric dental department for management of multiple asymptomatic dental caries. By taking periapical films, we found distal displacement of bilateral lower second premolar tooth germs which overlapped to first molar tooth germs, after finishing full mouth dental treatment. There were no clinical symptoms and signs but we kept regular follow-up by taking radiographic examinations. The second case was a 4-year-6-month-old boy without systemic diseases who came to our pediatric dental department due to lower left posterior area swelling and abscess formation for several days. According to Gutta-percha tracing and panoramic film findings, we found distal displacement of lower left second premolar tooth germ and its position was between second primary molar and first molar tooth germ. However, the clinical symptoms and signs were subsided after antibiotic therapy for 1 week, and there was no recurrence until now. As these two cases were still in primary dentitions, we would keep following-up on lower first molar eruption and the position of lower second premolar tooth germs. Orthodontic treatment or extraction will be considered in the future.

並列關鍵字

permanent first molar ； distal displacement of lower second premolar tooth germ ； primary dentition