Treatment of severe open bite and mandibular condyle anterior displacement by mini-screws and four second molars extraction:A case report

摘要

BACKGROUND Temporomandibular joint(TMJ)disorders are closely related to high-angle and skeletal Class II malocclusion.Sometimes pathological changes in the mandibular condyle can cause open bite to occur after growth is complete.CASE SUMMARY This article is about the treatment of an adult male patient with a severe hyperdivergent skeletal Class II base,an unusual and gradually occurring open bite and an abnormal mandibular condyle anterior displacement.Because the patient refused surgery,four second molars with cavities and root canal therapy were extracted,and four mini-screws were used for intrusion of the posterior teeth.The treatment duration was 22 mo,and after the treatment,the open bite was corrected and the displaced mandibular condyles were seated back to the articular fossa as shown by cone-beam computed tomography(CBCT).Based on the patient’s open bite history,the result of clinical examinations and CBCT comparisons,we believe it is possible that the occlusion interference was eliminated after the four second molars were extracted and the posterior teeth were intruded,and the patient's condyle spontaneously returned to its physiologic position.Finally,a normal overbite was established,and stable occlusion was achieved.CONCLUSION This case report suggested that identifying the cause of open bite is essential,and the TMJ factors for hyperdivergent skeletal Class II cases should be particularly examined.For these cases,intruding posterior teeth may place the condyle in a more appropriate position and provide an environment suitable for TMJ recovery.