The Study Of Correlation Between Mandibular Third Molars And Anterior Crowding

Objective:The aim of this study was to evaluate the clinical correlation between mandibular third molar and lower anterior crowding by analyzing plaster cast.and panoramic radiographs.The result will provide some useful clinical suggestions on how to make orthodontics treatment reasonable and durable.Methods:97 subjects were chosed who were between 20 to 30 years old.Firstly,All the subjects were grouped as Angel?(51 cases),?(21 cases),?(25 cases)based on their different sagittal skeletal facial types;Also,they were divided into high angle(40 cases),average angle(40 cases)and low angle(17 cases)group considering their different vertical skeletal facial types.Investigating the effects of different sagittal skeletal facial types and different vertical skeletal facial types on the impaction rate of mandible third molar.Secondly,all the subjects went through the measurement of lower anterior crowding.Investigating the effects of different sagittal skeletal facial types and different vertical skeletal facial types on lower anterior crowding.Lastly,third molars' conditions were judged on the base of their oral conditions and panoramic radiographs,and divide them into impacted(68 cases),normal(12 cases)and agenesis(17 cases).To study the relativity between different condition of third molar and lower anterior crowding.The impacted third molars were divided into vertical impaction(8 cases),horizontal impaction(11 cases)and mesioangular impaction(23 cases).It was purpose that analysis the impact of different impaction on lower anterior crowding.Furthermore,SPSS 22.0 was utilized to analyze the data and ?=0.05 was considered statistically significant.Data were analyzed using Paired Samples Test,Independent-Sample Test and variance analysis.Results:1.There was no significant differences among different sagittal skeletal facial types and vertical skeletal facial types,as well as between males and females considering the rate of mandibular third molars.2.The lower anterior crowding showed no statistical difference among different sagittal skeletal facial types and different vertical skeletal facial types,as well as between males and females.3.The lower anterior crowding was different between third molar impacted and agenesis,but not between normal and agenesis.The lower anterior crowding showed no statistical difference among different impaction.Conclusion:1.Gender,sagittal skeletal facial type and vertical skeletal facial type have no relations with the rate of mandibular third molars.2.Gender,sagittal skeletal facial type and vertical skeletal facial type have no relations with the lower anterior crowding.3.The impacted mandibular third molars has relation with the lower anterior crowding.The normal mandibular third molars had no relation with the lower anterior crowding.It suggesting that extracting agennetic third molar in front in case of anterior crowding.