Mechanical and Gravimetric Response of Surgical Suture Biomaterials to Commercial Mouthrinses During Static In Vitro Exposure

Surgical sutures are temporary load-bearing biomaterials whose performance in the oral cavity may be altered by postoperative mouthrinses. Seven USP 4-0 suture materials were immersed in four commercial mouthrinses for 3, 7, 10, and 14 days in a balanced factorial design (n = 3 per condition), with artificial saliva as a time-matched reference. Maximum breaking force (Fmax), apparent wet-state mass change, and solution pH were evaluated, and Day 14 re-dried mass was determined in an additional cohort (n = 5). Fmax was significantly affected by material, mouthrinse, time, and all interaction terms (p < 0.001), with material showing the largest main effect (partial η2 = 0.957). Mean Fmax decreased by 57.1% for PGA and 53.3% for PGLA between Days 3 and 14 when averaged across mouthrinses. PGLA also declined in artificial saliva (−49.1%), showing that temporal loss was not exclusive to mouthrinse exposure. Mean apparent wet-state mass change ranged from 85.1% for silk to 8.5% for nylon 66 and showed a weak pooled association with Fmax (r = −0.163, p = 0.086); suture-related pH shifts were small. Under static immersion, response was specific to the material–formulation pair and evolved with time. Continuous immersion without medium renewal or prior salivary conditioning does not reproduce intermittent clinical mouthrinse use.