[Application of 3D printing modified tooth-supported cyst plug in decompression of mandibular cystic lesions]

To evaluate the application value of 3D printing modified dental support cyst plug in fenestration of large jaw cystic lesions.

Forty patients with mandibular cystic disease in Xuzhou Central Hospital from October 2019 to April 2021 were selected. They were randomly divided into experimental group(3D printing group) and control group (traditional plug group), with 20 cases in each group. All enrolled patients underwent preoperative digital modeling of cystic lesions of the jaw, obtained the cystic cavity volume data of preoperative lesions, designed the windowing site according to the plan and performed decompression for jaw cysts. Three days after surgery, the patient's postoperative CBCT and Oral-scan data in the experimental group was obtained, and a digitally modified tooth-supported cyst plug with porous column channel was designed, and titanium alloy material for 3D printing was selected. In the control group, the plug was manually molded by experienced physicians. The visual analogue scale(VAS) score of pain, retention, mechanical properties of the plug and its effect on the adjacent teeth were compared between the two groups during the process of model preparation, and the changes of the cyst volume 1, 3 and 6 months after operation were compared between the two groups. SPSS 25.0 software package was used for data analysis.

Compared with the control group, the patients in the experimental group who made titanium alloy as printing material by digital impression complained more comfortable, and the mechanical strength and stability of the cyst plug were better than those in the control group(P＜0.05). There was no significant difference in retention between the two groups(P＞0.05). The reduction rate of cyst volume in the experimental group was significantly higher than that in the traditional plug group 3 and 6 months after operation(P＜0.05).

The modified tooth-supported titanium alloy cyst plug with digital 3D printing has good mechanical properties and stability. It has little damage to the abutment and no lateral force, and has the advantages of precision, individualization and comfort. The improved irrigation and injection channel can fully flush the cavity and speed up the narrowing of the cyst and reduce the waiting time before the second operation, which is worth promoting in clinical practice.