Walid Ahmed Ghanem, Naglaa Ali Mostafa And Amira Adel Hasanin,

ABSTRACT
Objective: The Aim Of This Study Was To Evaluate The Degenerative Effect Of Two Different Techniques On Condylar Cartilage Of Rabbits. Material And Methods:Twenty Seven Young Male New Zealand White Rabbits(3-4 Months Old) Were Randomized Into Three Equal Groups, Group I Control Group, Group II Unilateral Mandibular Posterior Teeth Extraction Was Done, While Group III Unilateral Forced Mandibular Hypermobility Was Induced. Three Animals Of Each Group Were Sacrificed After1,2and 3 Months Postoperatively And The Tested Temporomandibular Joints Sections Were Prepared For Immunohistochemical Analysis.The Expression Of Collagen Type II Degradation And IL-1? Were Quantified By Quantitative Histomorphometry.

Results: Interleukin-1? Reaction Measured By Histomorphometric Analysis Showed Increase In Average Area Percentage Among The Three Groups Throughout Study Intervals.IL-1?expression Was Significantly Increase In Mandibular Hypermobility Group (GP III)than Extraction Group (GPII)and Control Group(GP I) Respectively. Collagen Type II Degradation Reaction Measured By Histomorphometric Analysis Showed Increase In Average Area Percentage Among The Three Groups Throughout The Study Intervals.Collagen Type II Expression Was Significantly Higher In Mandibular Hypermobility (GP III) Than Extraction(GPII)while The Lowest In Control (GP I).There Was Significant Difference Between The Width Of The Articular Cartilage Of The Groups After One,two And Three Months.The Articular Width Was Thicker In Control Group (GPI),than Extraction Group(GPII) And The Lowest Thickness In Mandibular Hypermobility Group (GPIII). Conclusion: IL-1? Expression Is Directly Proportion With Collagen Type II Degradation On Articular Cartilage Degeneration.The Degenerative Effect Of Mandibular Hypermobility Has More Deleterious Rate On Condylar Cartilage Than That Of Unilateral Loss Of Posterior Teeth.