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Int Poster J Dent Oral Med 9 (2007), No. 2     15. June 2007

Int Poster J Dent Oral Med 2007, Vol 9 No 02, Poster 360

Tri-axial Accelerometric Analysis of Dynamic Patterns of Mandibular Movements

Language: English

Authors:
Dr. Ivica Pelivan1, Prof. dr. Melita Valentic-Peruzovic1, Dr. Ivan Michieli2, Dr. Amir Dubravic2, Dr. Amir Catic1, Dr. Iva Alajbeg1, Dr. Davor Illes1,
1 Department of Prosthodontics, School of Dental Medicine, University of Zagreb , Croatia
2 Electronic Department, Rudjer Boskovic Institute, Zagreb , Croatia

Date/Event/Venue:
September 13-16, 2006
PEF 2006 - Pan European Federation of IADR
Trinity College Dublin, Ireland

Poster Award
IADR CED Travel Stipend Award

Introduction

Accelerometric analysis represents a simple and unique method for acquiring specific dynamic data of mandibular movement which can be used for determining physiological as well as pathological dynamics' patterns.

Material and Methods

This pilot study included a healthy subject without any signs or symptoms of temporomandibular disorders which was determined using RDC/TMD examination protocol and computerized analysis of dental occlusion (T-Scan ®II, Tekscan, USA). Accelerations were measured by tri-axial MEMS wireless acceleration sensor (GLinkTM, Microstrain, USA) with range of ±10G and freely selected sweep rate of 1 kHz. Sensor was mounted on custom-made holder firmly fixed to subject's mandibular teeth to avoid soft tissues' movement artefacts. Acquisition of acceleration data was performed during mouth opening-closing cycles (OC), protrusive (P) and right and left laterotrusive movements (RL, LL) with predetermined pace and amplitude. By means of accelerometric data mean vertical and horizontal velocities of the mandible during movements were calculated. The comparison of acceleration values during mandibular movements was performed using analysis of variance (ANOVA) and pair wise comparisons (post-hoc Scheffe test).

Results

Raw tri-axial accelerometric data recorded during mandibular opening-closing cycles. Y-axis channel (vertical) acceleration and velocity graphs of mandibular opening-closing cycles.

Raw tri-axial accelerometric data recorded during mandibular opening-closing cycles are showed in Figure 1. Similar data were recorded during left and right laterotrusive as well as during protrusive movements of mandible. Analysis of acceleration and calculated velocity data during protrusive and laterotrusive movements also reveal regular, repetitive and recognizable patterns. Acceleration and calculated respective velocities in Y-axis (frontal plane) of opening and closing cycles demonstrate smooth, repetitive and distinctive patterns of mandibular movements (Figure 2). For the purpose of this study Y-axis (vertical) accelerometric values for different mandibular movements (Table 1) were analysed. The analysis of variance showed that acceleration values of performed mandibular movements were significantly different (P<0.05). The post-hoc Scheffe tests (Table 2) showed that differences were found between OC and three other mandibular movements (RL, LL and P) (P<0.05). There was no significant difference between RL and LL (P>0.05).

 

Mean SD SE 95% Confidence Interval for Mean
Lower Bound Upper Bound
OC 4,79 3,56841 0,79792 3,1199 6,4601
RL 1,192 0,79923 0,17871 0,8179 1,5661
LL 1,0915 0,70327 0,15726 0,7624 1,4206
PR 2,985 1,00625 0,225 2,5141 3,4559
Table 1: Descriptive statistics for acceleration values [m/s2] in Y-axis for different mandibular movements (OC, LL, RL and PR).

 

Mean Sig. 95% Confidence Interval for Mean
Lower Bound Upper Bound
OC RL 3,598 <0,001 1,8542 5,3418
LL 3,6985 <0,001 1,9547 5,4423
PR 1,805 0,039 0,0612 3,5488
RL OC -3,598 <0,001 -5,3418 -1,8542
LL 0,1005 0,999 -1,6433 1,8443
PR -1,793 0,041 -3,5368 -0,0492
LL OC -3,6985 <0,001 -5,4423 -1,9547
RL -0,1005 0,999 -1,8443 1,6433
PR -1,8935 0,028 -3,6373 -0,1497
PR OC -1,805 0,039 -3,5488 -0,0612
RL 1,793 0,041 0,0492 3,5368
LL 1,8935 0,028 0,1497 3,6373
Table 2: Comparison of acceleration values [m/s2] in Y-axis for different mandibular movements (ANOVA and post-hoc Scheffe test).

Conclusions

Acceleration and velocity during mouth opening-closing cycles demonstrate repetitive and distinctive dynamics patterns. They are significantly different (P<0.05) from patterns of protrusive and laterotrusive movements which also demonstrate repetitive and regular form. Those data could be used as the basis for time and spectral domain attribute description of regular and pathological mandibular movements. Accelerometric measurements could be applicable as diagnostic tool in analysis of mandibular movements.

Literature

  1. Flavel SC, Nordstrom MA, Miles TS. Postural stability of the human mandible during locomotion. J Biomech 2003; 36:759-764.
  2. Butcher MT, Ashley-Ross MA. Fetlock joint kinematics differ with age in thoroughbred racehorses. J Biomech 2002; 35:563-571.
  3. Throckmorton GS, Ellis E, Hayasaki H. Masticatory motion after surgical or nonsurgical treatment for unilateral fractures of the mandibular condylar process. J Maxillofac Surg 2004; 62:127-138.
  4. Perring S. Summers A. Jones EL. Bowen FJ. Hart K. A novel accelerometer tilt switch device for switch actuation in the patient with profound disability. Arch Phys Med Rehabil 2003; 84(6):921-923.
  5. Wang LA. Hu WM. Tan TN. Recent developments in human motion analysis. Pattern Recognition 2003; 36(3):585-601.
  6. Throckmorton GS, Ellis E, Hayasaki H. Jaw kinematics during mastication after unilateral fractures of the mandibular condylar process. Am J Orthod Dentofacial Orthop 2003; 124:695-707.

Abbreviations

Abreviations in Table 1 and Table 2:

OC opening-closing
RL right laterotrusion
LL left laterotrusion
PR protrusion
SD Standard deviation
SE Standard error


This Poster was submitted by Dr. Ivica Pelivan.

Correspondence address:
Dr. Ivica Pelivan
School of Dental Medicine
Department of Prosthodontics
University of Zagreb
Gunduliceva 5
HR-10000 Zagreb
Croatia