Clinical, Electromyographical and Radiological Comparison of Dawson’s Bimanual Technique of Guiding the Mandible with Wax Ball Orientation Technique©

Abstract

Introduction: There are numerous methods to guide the mandible into Centric Relation (CR). The Dawson’s bimanual technique is a time tested and established method to guide the mandible into CR. On the other hand the author of the present study also has copyrighted a technique (wax ball orientation technique©) to guide the mandible into CR. Hence, this methodological study was performed to compare the two CR techniques to guide the mandible in CR position using clinical, myographical and radiological assessment methods. Aim: To compare and assess which amongst the two (Dawson’s bimanual techniques, and wax ball orientation technique) CR guiding techniques best guides the mandible to CR position using clinical, electromyographical and radiological assessment methods. Materials and Methods: This interventional and clinical study was conducted at School of Dental Sciences, KIMSDU, Karad, Maharashtra, India, from May 2019 to May 2020. The study included healthy dentate individuals having Angle’s class I malocclusion without any occlusal interferences and an intact dentition except for 3rd molars. Two CR technique to guide the mandible were technique 1-Dawson’s bimanual technique and technique 2- wax ball orientation technique. The study was carried out in three phases: clinical, electromyographical and radiological. Difference between the centric points, workload on elevators, condylar position was statistically analysed. Descriptive statistics was used to analyse the difference between the centric points marked using both the techniques. Independent t-test was applied to compare the gender and the mean centric distribution. Results: Among the 45 study subjects considered for the study, 32 were females and 13 were males with the mean age of 21 years. No statistically significance difference was observed between the two techniques. Paired t-test showed that workload on elevators of both sides, Right Masseter in technique 1 and 2 had p-value=0.088, left Masseter in technique 1 and 2 had p-value=0.3, Right temporalis in technique 1 and 2 had p-value=0.463, left temporalis in technique 1 and 2 had p-value=0.429. There was difference between the Anteroposterior (AP) and Superoinferior (SI) position of condyle in relation to the fossa. AP measurement in the right side in tech 1 and 2 with p-value=0.448, AP measurement in the left side in tech 1 and 2 with p-value=0.178, SI measurement in the right side in tech 1 and 2 had p-value=0.803, SI measurement in the left side in tech 1 and 2 had p-value=0.259, which were statistically insignificant. Multivariate test showed statistically significant difference between gender and EMG, results whereas it was insignificant in Magnetic Resonance Imaging (MRI). Conclusion: The wax ball technique has similar accuracy as the Dawson’s Bimanual technique.

Keywords

• centric relation
• condyle
• magnetic resonance imaging
• masseter
• temporalis
• temporomandibular joint