Mohammed Atef Abd El Salam, Eman Sayed Elmasry And Randa Youssef Abd Al Gawad,

ABSTRACT
Background: The Mesio-distal Crown Diameter Of Teeth Is An Important Factor Which Affects The Alignment Of Teeth In The Bony Arches And The Development Of Occlusion During Transition Of The Dentition. Objective: Determine The Combined Mesio-distal Width Of The Permanent Mandibular Incisors And That Of The Maxillary And Mandibular Canines And Premolars In A Group Of Egyptian Children In Rural Areas Of Sohag Governorate. And To Find The Correct Relationship Of The Total Mesio-distal Widths Of Teeth Under Study. Methodology: This Study Was Held On 280 Patients With An Age Range From 12-16 Years Attending Schools In Rural Areas Of Sohag Governorate. Subjects Were Chosen To Be Free From Any Systemic Disease And Their Teeth Weren�t Carious Or Crowded. Impressions Were Made For Upper And Lower Arches. Each Impression Was Poured Immediately In Stone Plaster. Mesio-distal Widths Of Mandibular Incisors And Maxillary And Mandibular Canines And Premolars Were Measured From The Study Models Using Digital Caliper.

Results: The Teeth Size Of Males Was Slightly Larger Than That Of The Females. There Was No Statistical Significant Difference In The Mean Of Mesio-distal Tooth Width Between Right And Left Sides For Almost All Teeth Under Study. A Positive Correlation Existed Between The Sum Of The Mesio-distal Width Of Upper Right Canine And Premolars & The Sum Of The Mesio-distal Width Of The Lower Incisors Among Both Genders Combined. A Positive Correlation Between The Sum Of The Mesio-distal Width Of Upper Left Canine And Premolars & The Sum Of The Mesio-distal Width Of The Lower Incisors Among Both Genders Combined Was Evident. Conclusion: The Mesio-distal Width Of Upper And Lower Canines And Premolars Can Be Predicted By Measuring The Mesio-distal Width Of Lower Incisors Due To The Positive Correlation Found Between Them.