Thionolactone as a Resin Additive to Prepare (Bio)degradable 3D Objects via VAT Photopolymerization

Three-dimensional (3D) printing and especially VAT photopolymerization leads to cross-linked materials with high thermal, chemical, and mechanical stability. Nevertheless, these properties are incompatible with requirements of degradability and re/upcyclability. We show here that thionolactone and in particular dibenzo[c,e]-oxepane-5-thione (DOT) can be used as an additive (2 wt %) to acrylate-based resins to introduce weak bonds into the network via a radical ring-opening polymerization process. The low amount of additive makes it possible to modify the printability of the resin only slightly, keep its resolution intact, and maintain the mechanical properties of the 3D object. The resin with additive was used in UV microfabrication and two-photon stereolithography setups and commercial 3D printers. The fabricated objects were shown to degrade in basic solvent as well in a homemade compost. The rate of degradation is nonetheless dependent on the size of the object. This feature was used to prepare 3D objects with support structures that could be easily solubilized.

Visual loss reversed after treatment of acute bacterial sinusitis

Visual loss is a rare complication of acute bacterial sinusitis (ABS). Very few cases have been reported in the literature. Only two cases of visual loss reversed after treatment of ABS are found in the English-language literature. We present three cases in which significant visual loss was reversed after treatment of ABS. The experience with visual loss associated with ABS is small; therefore, no definitive statement about treatment can be made. However, on the basis of our experience, it appears that immediate surgical drainage with antibiotic therapy may be important in restoring vision.

Pediatric dacryocystorhinostomy

Dacryocystorhinostomy (DCR) often has uncertain results in the pediatric age group. Poorly defined and rapidly changing anatomy, along with a tendency toward vigorous growth of scar tissue, may alter surgical results. We report our experience with 29 primary pediatric dacryocystorhinostomies and five reoperations. Strict attention to surgical anatomy allows attainment of success results (83%) comparable with those in adults in both traumatic and nontraumatic cases. Our results, surgical technique, and evaluation of failures are discussed. Meticulous suturing of anterior and posterior flaps is not necessary for good surgical results. Dacryocystorhinostomy is a successful therapeutic modality in childhood dacryostenosis with chronic dacryocystitis when medical therapy, probing, and silicone intubation have been unsuccessful.