後継永久歯の位置異常を伴う下顎第二乳臼歯埋伏の1例
| Jazyk: | japonština |
|---|---|
| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | 小児歯科学雑誌. 47(5):773-779 |
| ISSN: | 0583-1199 |
| Popis: | 埋伏した下顎右側第二乳臼歯の咬合面側に後継永久歯である第二小臼歯歯胚が存在した稀な症例を経験したので報告する。患児は6歳8か月の女児で下顎右側第二乳臼歯は完全に埋伏していた。周囲歯肉に発赤，腫脹などは認められなかった。エックス線写真所見で，埋伏した乳臼歯の歯冠遠心上部に石灰化物が認められた。第二小臼歯の歯胚は乳臼歯の歯冠上部かつ近心舌側に歯軸を遠心に傾斜して認められた。6歳9か月時に開窓と過剰歯の除去を行い，その後開窓と牽引を行ったが萌出傾向がみられないため，第二乳臼歯を抜去した。その際，第二小臼歯の歯胚は保存した。第二乳臼歯の抜去からl年1か月後，第二小臼歯は萌出した。原因は不明であったが第二小臼歯歯胚が第二乳臼歯の歯根間に移動する過程で，何らかの障害が発生し第二小臼歯が咬合面側に留まり第二乳臼歯の埋伏が生じたと考えられた。後継永久歯歯胚の位置が逆転している症例では，永久歯の抜去例も報告されているが，本症例では状態や位置関係を精査した上で永久歯を保存し萌出まで導くことが可能であった。また，乳歯の埋伏は頻度が少ないものの，永久歯への影響も重大であるため，早期発見と処置が望ましいと考えられた。 We encountered a rare case of an impacted mandibular right second primary molar with the succeeding premolar located above the impacted primary molar. The patient was a 6-year, 9-month-old girl at her first visit. No signs of redness or swelling were noted in the gingiva on the impacted tooth. Radiographic examination revealed a calcified body on the upper and distal side of the impacted primary molar. The second premolar germ showed distal inclination and was located on the upper. mesial and lingual side of the affected primary molar. The crown of the impacted primary molar was fenestrated and the calcified body was removed. Four months later, the primary molar was fenestrated again and traction was started. Because the primary molar did not erupt in spite of the traction, the primary molar was removed under general anesthesia. At that time, the tooth germ of the second premolar was preserved intact. Approximately 1 year later, the second premolar appeared in the oral cavity. At the age of 12 years and 6 months, the affected premolar was aligned within the lower dental arch and its root showed good development on the radiographic photograph. Although the etiology could not be clearly concluded, it was speculated that the process of the migration of the second premolar into the inter-radicular position of the predecessor was disturbed by unidentified causes, and that the second primary molar was impacted because of retention of the primordium of the second premolar. It was indicated that we could preserve a permanent tooth in case of an impacted primary molar with an inverse successor germ which showed good condition and position. It should also be pointed out that the early detection and treatment of impacted primary teeth are important since the influence of impaction on a successor is very serious although the frequency of impaction of primary teeth is very low. |
| Databáze: | OpenAIRE |
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