Comparative Evaluation of Drill-Free and Self-Tapping Titanium Miniscrews for Semi-Rigid Internal Fixation in...

Conventional semi-rigid fixation systems in maxillofacial trauma use self-tapping titanium miniscrews (STS) that require preliminary drilling of a pilot hole. Although drill-free miniscrews (DFS) accompany these systems, they have not dominated practice despite their allure of improved screw-bone contact and holding power. The COVID-19 pandemic has brought these DFS to light as they avoid aerosol production. The present study has compared DFS to STS in patients being treated with miniplate fixation for maxillofacial trauma to understand their feasibility for maxillofacial fracture fixation.

This prospective case-control study sampled 16 patients each with zygomaticomaxillary buttress fracture and parasymphysis fracture of the mandible and grouped alternating patients as case (DFS) and control (STS). Intraoperatively duration of fixation, incidence of screw failures and fragment stability; postoperatively occlusion, neurosensory deficits, teeth vitality and infection and removal rates were evaluated at postoperative week 1, 3, 6, 12 and 24 using Cramer's V test. A P value < 0.05 was considered significant.

In the 32 patients evaluated, DFS reduced internal fixation time at zygomaticomaxillary buttress (P = 0.001) but not at parasymphysis (P = 0.206). No significant difference in screw failures or fragment stability was observed. Stable occlusion was maintained in all groups with vital teeth and intact neurosensory function, but the summative incidence of infection was significant at week 24 when STS was used at parasymphysis (P = 0.019).

While DFS may facilitate ease of insertion with a single instrument pick-and-screw-in approach, avoiding thermal osteonecrosis and aerosol production, they fail to confer any other clinical advantage.