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

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Statement of problemThe effect of different build angles on the tissue surface adaptation of complete denture bases manufactured by digital light processing (DLP) is unclear. PurposeThe 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. Material and methodsBoth 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). ResultsNo 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. ConclusionsIn 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.