[Comparison of two types of T-shaped coronectomy applied in extraction of impacted mandibular third molars].

Purpose: To compare the clinical efficiency of two types of T-shaped coronectomy applied in extraction of impacted mandibular third molars. METHODS：One hundred and twenty patients meeting with the criteria were randomly divided into 2 groups. Two types of T-shaped coronectomy were applied in extraction of impacted mandibular third molars.

[Diagonal root separation method for extracting impacted double-root mandibular third molars].

Double-root mandibular third molars are the common types of mandibular third molars that are prone to impac-tion. Based on the summary of clinical cases and experience, the commonly used crown-root separation technique is improved as diagonal root separation technique that divides the roots by the line connecting the distal axis angle to the root furcation. This new method improves the efficiency of the operation and reduces surgical trauma.