Basma M. Hagras, Safaa A. Ghobashy , Olfat M. Gab Allah And Mohammed M. El Laithy,

ABSTRACT


Introduction: Raising The Bite Is A Common Method In Orthodontics To Facilitate Several Treatment Procedures; However, This Method May Transmit Excessive Occlusal Forces Through The Periodontal Ligament. This Study Was Carried Out To Evaluate The Integrity Of The Root After Bite Raising To 3 Mm. Methods: Eighty Maxillary And Mandibular First Premolars Of 20 Patients Comprised The Sample For The Present Study. The Right Side Of Each Patient Was Selected As The Control While The Contralateral Side Was The Experimental. By The End Of The Experimental Period, One Month For Group I And Two Months For Group II , The First Premolars Were Extracted. Half Of The Samples Were Prepared For Scanning Electron Microscopic Examination, And The Others Were Prepared For Light Microscopic Examination.

Results: Root Resorption Began As A Superficial Multiple, Discrete, Small Pits That Merged And Coalesced To Form Wide Shallow Bays In Both Control Subgroups And Experimental Group I. In Experimental Group II, The Resorption Was Extended Deeply With Dentin Involvement And Undermining Resorption Was Observed. With Light Microscopic Examination, Mononucleated And Multinucleated Cells Were Noted In Relation To The Resorptive Areas. There Were Significant Differences In The Surface Area Of Root Resorption Between The Experimental And Control Subgroups, Between Experimental Subgroup I And Subgroup II. Apical Third Was The Most Common Affected One At Both Control With Significant Differences. Repair Of Resorped Areas Occurred In 80% Of The Control, 57% Of The Experimental Group I And Increased To 83% For The Control And 71% For The Experimental Group II. Conclusion: Root Resorption Occurred Concurrent With Bite Raising By 3 Mm For One And Two Months And Its Severity Increased With Time. Repair Of The Resorbed Area Started Early During Force Application And Increased With Time.