University Dental Clinic 2, Department of Prosthodontics, Friedrich-Alexander-University of Erlangen-Nuremberg, Glückstrasse 11, 91054 Erlangen, Germany.
Clin Oral Investig. 2011 Jun;15(3):427-34. doi: 10.1007/s00784-010-0395-9. Epub 2010 Mar 25.
When fabricating dental restorations, casts are usually transferred to the articulator based on arbitrary hinge axes or mean values instead of true hinge axis points. Using arbitrary hinge axis points or mean values can lead to occlusal errors if the vertical relation is changed in the articulator (e.g., when a centric record is used). This study predicted the probability of occlusal errors occurring in a group of subjects when casts are mounted based on arbitrary hinge axis points or mean values. In 57 healthy volunteers, true hinge axis points, arbitrary hinge axis points, right infraorbital point, maxillary incisal point, and the palatal cusps of the second molars were determined. Mean hinge axis points were established based on Balkwill angles between 17° and 25°. Occlusal errors evoked by cast mounting in relation to arbitrary or mean axes compared to true hinge axes were calculated. Errors were determined for vertical relation settings of 2 and 4 mm. With 2 mm vertical relation, occlusal errors ≥340 µm occurred with a 10% probability with arbitrary hinge axis mounting. At the same probability level, the error increased moderately to ≥440 µm with mean value mounting and a Balkwill angle of 17°. With a Balkwill angle of 25° occlusal errors ≥1,120 µm occurred with 10% probability. Occlusal errors increased considerably with a vertical relation setting of 4 mm. If vertical relation shall be altered, a transfer of the casts according to arbitrary hinge axes is recommended. If casts are transferred according to mean values, errors are bigger depending on the articulator used.
在制作牙科修复体时，通常根据任意铰链轴或平均值将印模转移到架上，而不是真正的铰链轴点。如果在架上改变垂直关系（例如，使用正中记录），使用任意铰链轴点或平均值可能会导致咬合误差。本研究预测了当根据任意铰链轴点或平均值安装印模时，一组受试者发生咬合误差的概率。在 57 名健康志愿者中，确定了真正的铰链轴点、任意铰链轴点、眶下点、上颌切牙点和第二磨牙的腭尖。基于 17°至 25°之间的 Balkwill 角建立了平均铰链轴点。计算了与真实铰链轴相比，在任意或平均值轴上安装印模时引起的咬合误差。确定了 2 和 4mm 垂直关系设置的误差。在 2mm 的垂直关系下，使用任意铰链轴安装时，咬合误差≥340µm 的概率为 10%。在相同的概率水平下，随着 Balkwill 角度为 17°的平均值安装，误差适度增加到≥440µm。Balkwill 角度为 25°时，咬合误差≥1,120µm 的概率为 10%。垂直关系设置为 4mm 时，咬合误差会显著增加。如果要改变垂直关系，建议根据任意铰链轴转移印模。如果根据平均值转移印模，则误差会根据使用的架而变大。
