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Reliability of an ear-bow arbitrary face-bow transfer instrument
D G Choi1, J F Bowley, D B Marx
1Department of Prosthodontics, Kyung-Hee University, College of Dentistry, Dongdaemoon-Gu, Seoul, Korea. choi@nms.kyunghee.ac.kr
The Journal of Prosthetic Dentistry
|July 29, 1999
Summary
Dentists using arbitrary ear-face-bow instruments may encounter up to +/-1.2 mm of error when mounting maxillary casts. Operator variability did not significantly affect vertical or horizontal orientation but impacted posterior measurements.
Area of Science:
- Dental prosthodontics
- Biomechanical analysis
Background:
- Maxillary arch orientation to temporomandibular joint articulation is critical.
- Operator and equipment variability can introduce technical errors in dental procedures.
Purpose of the Study:
- To assess the variability among dentists using an arbitrary ear-face-bow instrument for maxillary cast mounting.
- To quantify potential errors in spatial orientation during the mounting process.
Main Methods:
- A single maxillary cast was mounted by three dentists using a common arbitrary ear-face-bow instrument.
- Coordinate measurements with a machinist's microscope tracked spatial orientation changes at four reference points.
- Repeated measures ANOVA and Wilks' Lambda test analyzed spatial orientation variations.
Main Results:
- A 95% confidence interval indicated a potential error range of +/-1.2 mm for dentists using this instrument/articulator combination.
- No significant differences in vertical or horizontal spatial orientation were found among the dentists.
- Statistically significant differences were observed in linear distance changes on the patient's posterior right side.
Conclusions:
- The study identified a range of inherent error attributable to the operator when using this specific ear-face-bow instrument.
- Operator variability influences specific spatial measurements, particularly on the posterior aspect.