Effect of bicortical orthodontic microimplant on tooth movement in dogs / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the potential anchorage of bicortical microimplant for tooth movement.</p><p><b>METHODS</b>Five bicortical microimplants were inserted in the interradicular area of the second premolar (P2) in one side of the mandible (test side), 5 monocortical microimplant in the contralateral region (control side) in 5 beagle dogs. A total of 100 g force was generated between the implant and the fourth premolar (P4) in two sides. M1-P4, CA-IB and CA-M1 were measured biweekly. At the end of loading, specimens with P4 segments were cut and grounded to 70 microm to calculate the bone-to-implant contact (BIC).</p><p><b>RESULT</b>All the bicortical microimplants remained stable during the treatment periods, while 1 monocortical microimplant was lost within 1 week. Mesial movement of P4 was ( 3.92+/-0.22) mm in the test side, (2.03+/-0.15) mm in the control side (P<0.05). Analysis showed no difference of the BIC between the bicortical microimplants and the monocortical microimplants.</p><p><b>CONCLUSION</b>The bicortical microimplant may be used as orthodontic anchorage for mesial movement of posterior tooth.</p>

Dental malocclusion among juveniles in Hangzhou municipality / 浙江大学学报·医学版

OBJECTIVE: To investigate the prevalence rate, malocclusion type and treatment rate as well as awareness of malocclusion among children and adolescents living in the Hangzhou municipality. METHODS: 1818 children and adolescents ages 7 approximate, equals 16 living in Hangzhou municipality were evaluated. RESULTS: The overall malocclusion rate was 35.75%. In Angle's classification: Angle I 593 cases (32.62%), Angle II 48 cases(2.64%),Angle III 9 cases (0.49%). Among the malocclusion type of crowding was mixed dentition 70.66%,permanent dentition 85.89%. In the overjet malocclusion mixed dentition was noted in 60.57% and permanent dentition in 51.05%.The type of overbite was mixed dentition 67.82%,permanent dentition 31.23%. In the crossbite of anterior teeth mixed dention was noted in 12.30% and permanent dention in 9.91%. Overall treatment rate for malocclusion was 10.15%.CONCLUSION: Among Hangzhou municipality juveniles there is both inadequate prevention and treatment of dental malocclusion.