Study On Prediction About Mesiodistal Crown Diameters Of Teeth From Different Classes Of Malocclusion Based On Genetic Algorithms Method

Objective:Use genetic algorithms(Genetic Algorithms, called GAS)methodto establish an equation between mesiodistal crown diameters ofdifferent types of malocclusion teeth and that of other teeth and usejust one equation to describe the situation of the teeth with the sameposition and the same gender. Looking for a simple, accuratemethod to predict teeth mesiodistal crown diameters, In order tomake the guidance for clinical analysis of gap.Method:Screen out malocclusion patients’pre-treatment casts diagnosedas classⅠ, Ⅱ, Ⅲ with100for each type and50males,50females respectively. Among these,45are designed as analogsamples and the other5casts work as test samples. Use verniercaliper to measure teeth mesiodistal crown diameters, teeth crownwidth using SPSS for statistical analysis, and using regressionanalysis to identify predictors. Separately for different types ofmalocclusion using linear regression analysis and genetic algorithm to establish an equation between mesiodistal crown diameters ofteeth and that of adjacent teeth. The sample which is used tooptimize equation coefficients are called analog samples (45), theother as a sample test equation is called the test sample(5).Compared the accuracy of the equation analyses by two kinds ofmethod.Results:1.SPSS analysis showed that the majority of teeth on left and rightsides of the same name about tooth crown width was no significantdifference (p>0.05); part of the teeth was statistically significantwhich tooth crown width with the same sex in different types ofmalocclusion with the same name compared (p <0.05). Differenttypes of malocclusion of the same sex tooth with the same namecrown width compared, most teeth statistically significant (p <0.05).2. Using stepwise regression analysis of the relevant data wereanalyzed, the results showed that the majority of teeth adjacent teetharound its crown width greater, the correlation coefficient wasstatistically significant (P <0.05), and other non-adjacent teethweakly correlated (P>0.05). 3. Use linear regression method to establish an equation betweenmesiodistal crown diameters of different types of malocclusion teethand that of other teeth.4. Using GAS to establish a different type of malocclusion eachtooth crown width of two adjacent correlation equation.5. Compared GAS with linear regression analysis, error of testsamples showed no significant difference (P>0.05), but the testsamples GAS mean absolute error is less than linear regressionanalysis.Conclusion:1.Tooth crown width of the same name in different genders havedifferences.2. There is a difference between the width of the same name toothcrown of different types of malocclusion.3. The tooth crown width which in the same dental arch are closelyrelated to the adjacent two tooth crown width.4.GAS established prediction equation accuracy is better thanlinear regression analysis established equation. And conducived tothe incomplete eruption patients for total tooth precision column space analysis on different sexes and malocclusion type of dentition,can guide the work of clinical orthodontic treatment.