Reproduction accuracy of articulator mounting with an arbitrary face-bow vs. average values-a controlled, randomized, blinded patient simulator study.


Department of Prosthetic Dentistry, School of Dental and Oral Medicine, University Hospital Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany. [Email]


OBJECTIVE : The benefit from positioning the maxillary casts with the aid of face-bows has been questioned in the past. Therefore, the aim of this study was to investigate the reliability and validity of arbitrary face-bow transfers compared to a process solely based on the orientation by means of average values. For optimized validity, the study was conducted using a controlled, randomized, anonymized, and blinded patient simulator study design.
METHODS : Thirty-eight undergraduate dental students were randomly divided into two groups; both groups were applied to both methods, in opposite sequences. Investigated methods were the transfer of casts using an arbitrary face-bow in comparison to the transfer using average values based on Bonwill's triangle and the Balkwill angle. The "patient" used in this study was a patient simulator. All casts were transferred to the same individual articulator, and all the transferred casts were made using type IV special hard stone plaster; for the attachment into the articulator, type II plaster was used. A blinded evaluation was performed based on three-dimensional measurements of three reference points.
RESULTS : The results are presented three-dimensionally in scatterplots. Statistical analysis indicated a significantly smaller variance (Student's t test, p < 0.05) for the transfer using a face-bow, applicable for all three reference points.
CONCLUSIONS : The use of an arbitrary face-bow significantly improves the transfer reliability and hence the validity.
CONCLUSIONS : To simulate the patient situation in an individual articulator correctly, casts should be transferred at least by means of an arbitrary face-bow.


Dental articulators, face-bow,Dental occlusion, vertical dimension,Jaw relation record/instrumentation,Methods, reproducibility of results, confidence intervals, analysis of variance, evidence-based dentistry,