Recording sagittal condylar angles using a mandibular facebow

Area of Science:

• Dentistry
• Biomechanics
• Craniomandibular studies

Background:

• Sagittal condylar inclination (SCI) is crucial for simulating jaw movements in dental articulators.
• Accurate SCI values are essential for prosthodontic treatments and understanding TMJ function.
• Previous studies have reported varied SCI angles, necessitating further investigation into reliable measurement techniques.

Purpose of the Study:

• To determine the average sagittal condylar inclination angles in dentate subjects.
• To evaluate the correlation between measured SCI angles and articulator settings.
• To assess the repeatability and accuracy of a specific measurement method using a mandibular facebow.

Main Methods:

• 103 dentate subjects were included in the study.
• A mandibular facebow with pencil tracing styli was used to record protrusive excursions.
• Tangents to the traced curves were measured using a protractor to determine SCI angles and assess reproducibility.

Main Results:

• The mean left SCI angle was 32° and the mean right SCI angle was 31.5°, with no significant difference between sides (P=0.609).
• Significant differences were observed in individual right and left measurements within groups (P=0.0000).
• The method demonstrated high reproducibility, with minimal variation between operators (mean 33.3°) and within a single operator (mean 32.9°).

Conclusions:

• The average SCI angles align with existing literature, supporting 30° as an appropriate setting for fixed articulators.
• The mandibular facebow method with pencil tracing is a reproducible and accurate technique for recording SCI angles.
• This method's accuracy is suitable for both individual operator use and inter-operator assessments in clinical and research settings.