難易度指数分類の提案による、有歯顎と小臼歯の包括的分類：4165症例の単一施設による評価

A comprehensive classification for impacted cuspids and bicuspids with a proposal for Difficulty Index Categorization: a single center evaluation of 4165 cases.

抄録

背景:

本研究の目的は、上顎および下顎アーチにおける空間的な位置とX線学的な外観に基づいて、有歯顎および小臼歯の分類を提案することである。

BACKGROUND: The aim of the current study was to propose a classification of impacted cuspids, and bicuspids based on their spatial position in the maxillary and mandibular arches and their radiological appearance.

方法:

この前向き研究は、抜歯、矯正治療、永久歯の犬歯/小臼歯の欠損、第三大臼歯の抜歯のために当センターに来院したすべての患者を対象として実施した。6ヶ月以内に報告された全ての患者がこの研究に登録された。診断の一環として、全患者にオルソパントモグラムを勧めた。パノラマX線写真と臨床データを検討し、小臼歯と犬歯の埋伏が確認された患者を研究に組み入れ、埋伏歯の3次元位置を評価するためにコーンビームCT検査を受けるよう勧めた。治療計画は、埋伏歯の位置と矯正移動の可能性に基づいて決定された。標準的な手術プロトコールが全患者に適用された。切開から縫合までの処置時間を集計し、抜歯の難易度を現在の難易度指数と関連付けて検証した。

METHODS: This prospective study was conducted including all the patients who reported to our center for extractions, orthodontic treatment, missing permanent cuspids/bicuspids, removal of third molar teeth. All patients who reported within a time frame of 6 months were enrolled in the study. Orthopantomogram was advised for all the patients as a part of diagnostic work up. The panoramic radiographs and clinical data were reviewed and patients with evidence of impacted bicuspids and cuspids were included in the study and were advised to undergo a cone beam computed tomography to evaluate the 3-dimensional position of the impacted teeth. Treatment plan was decided based on the position of the impacted teeth and feasibility for orthodontic movement. Standard surgical protocol was followed for all the patients. The duration of the procedure from the time of incision till the suturing were tabulated and the difficulty of extraction was correlated with the current Difficulty Index to validate the same.

結果:

合計4165人の患者が研究に登録され、包含・除外基準に基づき、3680人の患者が除外され、487人の有歯顎/小臼歯患者が研究に組み入れられた。合計231人の患者が上顎の犬歯と小臼歯に衝撃を受け、256人の症例が下顎の犬歯と小臼歯に衝撃を受けた。256例の下顎犬歯と小臼歯のうち、62％がCの位置にあり、残りの38％はBの位置にあった。上顎の73％の歯がCの位置にあり、その69％は移動しているか（29％）、歯槽骨に水平に埋伏しているか（38％）、反転していた（2％）。残りの31%は、中間に傾斜しているか垂直であることがわかった。下顎の犬歯と小臼歯は、上顎の歯に比べ、BとCのポジションで外科的除去に時間がかかり、これは統計的に有意であった。

RESULTS: A total number of 4165 patients were enrolled in the study and based on the inclusion and exclusion criteria, 3680 patients were excluded and 487 patients with impacted cuspids/bicuspids were included in the study. A total number of 231 patients had impacted maxillary cuspids and bicuspids and 256 cases had impacted mandibular cuspids/bicuspids. Amongst the 256 mandibular cuspid and bicuspid that were impacted, 62% were in position C while the rest of 38% were in position B. More than ⅓ of the teeth which were in position C had transmigrated (35%). Seventy-three percent of the maxillary teeth were in position C and 69% of these teeth were either transmigrated (29%), or were horizontally (38%) placed in the alveolus or inverted (2%). The rest of the 31% were found to be either mesially inclined or vertical. The average Difficulty Index for maxillary teeth was 8 and mandibular teeth was 9. Mandibular cuspids and bicuspids in position B and C took longer time for surgical removal compared to the maxillary teeth and this was statistically significant.

結論:

下顎小臼歯および小臼歯の埋伏歯に関する臨床分類は、歯列内の歯の3次元的な位置に基づいた治療計画を立てるための構造的なアプローチを提供する。

CONCLUSIONS: The proposed clinical classification on impacted mandibular cuspids and bicuspids provides a structured approach to plan the treatment based on the 3-dimensional position of the teeth in the arch.