デジタル光造形で製作された上顎および下顎総義歯床の組織表面適合性に及ぼす造形角の影響について

The effect of build angle on the tissue surface adaptation of maxillary and mandibular complete denture bases manufactured by digital light processing.

抄録

問題提起:

デジタルライトプロセッシング（DLP）により製作された総義歯床の組織表面適合性に及ぼす造形角の違いによる影響は明らかではない．

STATEMENT OF PROBLEM: The effect of different build angles on the tissue surface adaptation of complete denture bases manufactured by digital light processing (DLP) is unclear.

目的:

本研究の目的は，DLPにより製作された総義歯床の組織表面適合性に及ぼす造形角の影響を評価することである．

PURPOSE: The purpose of this in vitro study was to evaluate the effect of build angle on the tissue surface adaptation of DLP-printed complete denture bases.

材料および方法:

上顎および下顎の義歯床を基準模型をもとに仮想的に設計し，DLP法により作製した．各アーチについて，90，100，135，150度の4種類の築盛角度で40個の義歯床を作製し，4群（90D，100D，135D，150D，各群10個ずつ）に分けた．各DLP義歯床のインタリオ面をスキャンし，基準キャストの無歯顎部に重ね合わせ，組織表面適合の程度を比較した．二乗平均平方根推定値，正平均偏差値，負平均偏差値を測定し，カラー偏差マップにて表示した．統計解析にはMann-Whitney検定とKruskal-Wallis分散分析を用いた（α=.05）．

MATERIAL AND METHODS: Both maxillary and mandibular denture bases were virtually designed based on reference casts and fabricated by the DLP technique. For each arch, a total of 40 denture bases were fabricated with 4 different build angle conditions (90, 100, 135, and 150 degrees) and divided into 4 groups (90D, 100D, 135D, and 150D; 10 denture bases per group). The scanned intaglio surface of each DLP denture base was superimposed on the scanned edentulous area of the reference cast to compare the degree of tissue surface adaptation. Root-mean-square estimate, positive average deviation, and negative average deviation values were measured and displayed with a color deviation map. The Mann-Whitney test and Kruskal-Wallis analysis of variance were used for statistical analyses (α=.05).

結果:

上顎弓，下顎弓のいずれの築造角度群においても，二乗平均平方根推定値に統計学的な有意差は認められなかった．上顎弓では，築造角度の増加に伴い，正偏差の領域が口蓋部から後口蓋封鎖部へ移動し，負偏差が後結節で顕著になった．上顎弓では，135D 群の表面偏差の色分布が良好であった．下顎弓では，唇側斜面から隆起部にかけて正の偏位が認められ，頬側棚と後臼歯部では負の偏位が認められた．100D群では，下顎の表面偏差の分布が良好であった．

RESULTS: No statistically significant differences were found for root-mean-square estimate values among any build angle groups in either the maxillary or mandibular arch. With the increase of build angles, the area of positive deviation in the maxillary arch moved from the palatal region to the posterior palatal seal area, and negative deviation became pronounced at the posterior tuberosity. In the maxillary arch, the 135D group showed favorable color distribution of surface deviation. In the mandibular arch, a positive deviation was detected at the labial slope to the crest of the ridge, whereas a negative deviation was observed at the buccal shelf and the retromolar pad. The 100D group showed favorable distribution of surface deviation in the mandible.

結論:

両アーチにおいて、4つのビルドアングルで組織全体の表面適応度の差は統計的に有意ではなかった。しかし，上顎のDLP床では135°，下顎のDLP床では100°が適切であることが色彩偏差マップにより明らかとなった．

CONCLUSIONS: In both arches, the difference of overall tissue surface adaptation was not statistically significant in the 4 different build angles. However, the color deviation map revealed that the 135-degree build angle may be appropriate in the maxillary DLP-printed denture base and the 100-degree angle, in the mandibular denture base.