再植歯の長期経過観察のための口腔内X線写真の幾何学的標準化のための方法：症例報告

A method for the geometric standardization of intraoral radiographs for long-term follow up of replanted teeth: a case report.

抄録

歯牙移植後の経過観察期間中に撮影された一連のX線写真の解釈は、特に露光の投影形状を適切に再現できないなど、いくつかの困難を伴う場合がある。本稿では，歯槽骨外傷の長期経過観察のために，咬合器にフィルムホルダーを取り付けた特注装置を用いて口腔内X線写真の幾何学的標準化を行う方法について述べる．上顎中切歯の剥離を受け，生理食塩水で4時間保存後，再植した患者を対象に本法を適用した．外傷後7日目から歯内療法を開始し、最初の2ヶ月間は15日ごとに水酸化カルシウムの管内投与薬を交換し、その後30日間隔で8ヶ月間行った。この期間後に根管充填が行われた。歯根吸収など修復過程で起こりうる変化を確認するため，経過観察時に撮影したX線写真を標準化した．アルジネートで上顎弓の印象をとり，その模型を石膏で鋳造し，アセテート咬合器を作製した．咬合スプリントにRinn X-C-Pフィルムホルダーと長さ5mmの0.7mm矯正用ワイヤーを自己重合アクリル樹脂で固定し，X線撮影の標準化に用いる特注器具を作製した．再植後10ヶ月から76ヶ月まで、4ヶ月間隔でX線写真を撮影した。画像はデジタル化され、ディゴラシステムを用いて分析された。中切歯の長さは、露光の投影形状の再現性を確認するために決定し、矯正用ワイヤーは、X線写真で長さを推定する際の精度を評価するために使用された。本稿で紹介した口腔内X線写真の幾何学的標準化の方法は，幾何学的な撮影パラメータを一貫して再現するものであり，歯槽骨外傷症例のX線写真フォローアップに使用することが可能である．

The interpretation of the set of radiographs taken during the follow-up period after tooth replantation might pose several difficulties, especially the inability to adequately reproduce the projection geometry of the exposures. This article describes a method for the geometric standardization of intraoral radiographs using a custom-made apparatus comprising a film-holder attached to an occlusal splint for the long-term follow up of dentoalveolar trauma. The method was applied in a patient who suffered an avulsion of the maxillary central incisors and had the teeth replanted after 4 h in saline storage. Endodontic treatment started 7 days after the trauma with changes of a calcium hydroxide intracanal medication every 15 days in the first 2 months and thereafter at 30-day intervals for 8 months. Root canal filling was carried out after this period. The radiographic exposures taken at the follow-up visits were standardized to identify the possible alterations during the repair process, such as root resorptions. A maxillary arch impression was made with alginate, and the model was cast in stone for fabrication of an acetate occlusal splint. The custom-made apparatus used for standardization of the radiographic exposures was fabricated by fixing a Rinn X-C-P film-holder and a 5-mm-long piece of 0.7-mm orthodontic wire to the occlusal splint with autopolymerized acrylic resin. Radiographs were taken at 4-month intervals, starting 10 months after replantation up to 76 months. The images were digitized and analysed using the Digora system. The length of the central incisors was determined to verify the reproduction of the projection geometry of the exposures and the orthodontic wire served to assess accuracy during length estimations in the radiographs. The method described in this article for geometric standardization of intraoral radiographs provided a consistent reproduction of the geometric exposure parameters, being indicated for use in the radiographic follow up of cases of dentoalveolar trauma.