Body Position And Occlusal Contacts In Lateral Excursions.pptx

prosthodontics

1. Body Position And Occlusal Contacts In Lateral Excursions : A Pilot Study Spijker et al, Int J Prosthodont , 2011; 24: 133-136

2. CONTENTS Introduction Review Aim of the study Materials and methods Results Discussion Conclusion References

3. Introduction Dynamic occlusion is the study of the contacts that teeth make when the mandible is moving – contacts when the jaw moves sideways, forwards, backwards, or at an angle. The contacts are not points, they are lines Relations of two objects involving the element of relative movement of one object to another, as the relationship of the mandible to the maxillae (GPT-4)

4. INTRODUCTION Static occlusion Study of contacts between the teeth when the jaw is not moving. The contacts are points The relationship between two parts that are not in motion ( GPT – 8 )

5. Review Mc. Lean , 1973 – jaw closure in tilted body positions resulted in different initial occlusal contacts. The combination of the increasing antigravity reflex activity , the lengthening of the masseter muscle to its normal resting length, and the shift of the entire mandible to a less retruded position may account for the changing contact pattern and increased intercuspation , as registered on the wax wafers after stimulated jaw closures as the body was raised from a supine to an upright position .

6. Visscher – 2000 - The influence of head posture upon the kinematics of the mandible is probably a manifestation of differences in mandibular loading in the different head postures

7. Aim of the study To explore if tooth contacts during lateral excursions are influenced by tilted body positions.

8. Materials and methods 30 students (22 to 34 years of age; 8 men, 22 women) 22 faculty staff members (31 to 64 years of age; 11 men, 11 women ) Inclusion criteria : Complete dentitions Free of any signs or symptoms of temporomandibular disorder.

9. Subjects were instructed to perform a lateral excursion from maximal occlusion to the point where the canines were in an end-to-end position. Shim stock articulation foil, held by a pair of pincers Working and nonworking side contacts registered.

10. Registrations were performed One trained observer Intra observer reliability – re-examining 10 subjects.

11. Frequencies of the changes in occlusal contacts resulting from tilting the body position were calculated.

12. Results

13. The majority of subjects had Canine guidance (44 %) Group function (40%) in the upright position The number of changed tooth contacts per subject ranged from 0 to 22. Two subjects (4 %) – no change in tooth contacts. Working side – 83 % of subjects had 7 or more changes in tooth contacts Non – working side – 48 % had 7 or more changes

14. Discussion Reliability of recordings of dynamic occlusion also depends on the accuracy and reproducibility of the repeated jaw movement. Consistent occlusal forces are very difficult to control and may vary each day Pilot study - Frequency of changes in occlusal contact during lateral excursions resulting from altering the body position differs largely between subjects . This study describes a relationship between body position and the manner in which occlusal contacts are presented.

15. Conclusion For the majority of subjects, the number of dynamic occlusal contacts changed when the body position was altered

16. References McLean. Effects of changing body position on dental occlusion. J Dent Res 1973;52: 1041–1045 . Ogawa. Validity of the examination method of occlusal contact pattern relating to mandibular position. J Dent 2000;28:23–29. Visscher CM. Kinematics of the human mandible for different head postures. J Oral Rehabil 2000;27:299–305.

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