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.