Fixed prosthodontic impression workflows position the printed tray made from Prodways PLASTCure Dental Tray Liquid Resin as a rigid carrier for low- to medium-viscosity polyvinylsiloxane wash materials after the preparation margins have been digitized or captured in a preliminary putty. A uniform 1.5–2.0 mm intaglio relief from the prepared arch is maintained in the CAD design because light-body addition silicone wash materials commonly exhibit viscosity values between 25,000 mPa·s and 45,000 mPa·s; smaller relief gaps generate hydraulic seating pressure that can elastically distort the printed wall and produce incomplete wash injection at the proximal margins. The resin is a single-component liquid photopolymer, so no mixing ratio applies before printing; instead the bottle is conditioned to 22–25 °C and slowly rolled to eliminate air bubbles, since an entrapped bubble as small as 0.5 mm can survive both the wash and post-cure steps and form a shallow pit on the intaglio surface. Printing is carried out on 405 nm DLP or LCD systems with a nominal layer thickness of 50 µm, and exposure is adjusted so that the working curve produces a polymerized film thickness 15–20% greater than the layer increment; this provides secure interlayer conversion without the horizontal build-out that accompanies strong overexposure. Wall thickness is set at 2.0–2.5 mm on buccal and lingual flanges and increased to 3.0 mm at the handle junction where withdrawal loads concentrate. Supports are anchored only on external surfaces, never on the intaglio, because residual support nibs inside the impression space transfer as topographic defects to either polyvinylsiloxane or polyether wash films and compromise marginal read-out. After completion the tray is washed in two successive 97% isopropanol baths, the first for 3 min and the second for 2 min, using ultrasonic agitation, then dried with oil-free compressed air. Post-curing in a fitted UV post-cure oven at 40–60 °C for 20–30 min raises conversion of residual methacrylate species and lowers the risk of monomer migration during short-term mucosal contact; however, thermal deviation above 60 °C can distort large unsupported flanges. Device documentation falls under ISO 13485:2016 for custom device batch release, and biological safety is assessed under ISO 10993-1:2018 for short-term mucosal contact. The terminal device is a custom tray that receives a specified polyvinylsiloxane tray adhesive and is used once for the definitive impression, then discarded.

What limits border-moulding accuracy when a full-arch tray is printed with vertical stair-step facets at the vestibular periphery?

For full-arch edentulous impressions the printed tray must carry a border-moulding material while maintaining a 2–3 mm peripheral relief from the alveolar ridge and the vestibular reflection. The CAD geometry positions the tray periphery approximately 1.0–1.5 mm short of the functional sulcus depth so that a bead of border-moulding compound or heavy-body polyvinylsiloxane can be applied and muscle-trimmed without the printed rim impinging on the insertion of the mylohyoid or buccinator muscle. A critical process conflict arises from the choice of print orientation. If the tray is oriented horizontally on the build plate, the outer border contour is constructed from stacked 50 µm layers that create stair-step facets along a curved surface; these facets can interrupt the border seal between the tray edge and the border-moulding material, producing a wax-like interlock that displaces the material during muscle trimming. Instead the tray is tilted 10–15° relative to the build plane in both x and y axes, which redistributes the layer seams away from the critical peripheral border but increases the need for supports on the intaglio side. Because the resin is single-component and requires no mixing, viscosity control is performed by temperature alone; at 22–25 °C the resin recoating window remains stable for 50 µm layers, while lower temperatures raise viscosity and cause incomplete layer spreading across the large flat palatal region. After printing, the intaglio surface is lightly blasted with 50 µm aluminium oxide at 2 bar to provide microretention for alginate or polyvinylsiloxane adhesives; this step is not a substitute for tray adhesive but improves adhesive wetting on the smooth as-printed surface. Post-curing is carried out at 40–60 °C for 20–40 min, with the tray supported on a contoured fixture because the thermal expansion difference between the resin and an unsupported flat post-cure bed can induce warping greater than 0.3 mm in the posterior palatal span. The peripheral border must meet the fit criteria defined in the dental laboratory’s ISO 13485:2016 work instruction; because the tray is short-term mucosal contact, biological evaluation follows ISO 10993-1:2018, ISO 10993-5:2009, and ISO 10993-23:2021. The terminal product is a full-arch custom tray used with reversible impression compound or putty for border moulding followed by a wash of polyvinylsiloxane or polyether.

Open-tray implant transfer appliances and coping access port reinforcement

Open-tray implant impression procedures require the printed tray to record coping positions from a scan that captures implant analog locations or from a splinted transfer coping pattern, and the tray must carry the copings through openings in the occlusal surface while the impression material sets. The access port diameter is set 1.5–2.0 mm larger than the transfer coping or the screw access chimney to allow direct screwdriver access to the implant screw without binding; a narrower port causes lateral stress on the printed wall when the screwdriver is inserted, and a wider port removes too much occlusal cross-section and reduces tray stiffness across the span. The wall thickness around each access port is reinforced to 3.0 mm, with a 1.0 mm fillet radius at the port-to-wall transition, because the port region acts as a stress concentration during jaw separation and during removal of the tray after the copings have been unscrewed. The single-component liquid resin has no mixing ratio; processing temperature is maintained at 22–25 °C, and the build is oriented so that the long axis of each access chimney is vertical to the build plate. This orientation confines the stair-stepping to the external surface and keeps the internal channel smooth enough for the coping to be retracted without an underextended lip that could catch the polyvinylsiloxane set material. Layer thickness is 50 µm, and exposure is held within the saturation window but not beyond it; overcure in the through-hole region increases the measured hole diameter above the CAD dimension and can compromise the relationship between the coping screw access and the port wall. After printing, the tray is washed in 97% isopropanol in two sequential baths and post-cured at 40–60 °C for 20–30 min. Dimensional validation of each open-tray appliance is performed with calibrated calipers at the access port diameter and the inter-port center-to-center distance; if the center-to-center deviation exceeds 0.25 mm, the process capability of the printer and the post-cure support fixture must be revalidated before clinical use. Risk management for open-tray port dimensions follows ISO 14971:2019, and the dental laboratory retains the custom device file under ISO 13485:2016. The terminal output is a rigid open-tray transfer appliance that retains splinted or non-splinted implant copings in a polyvinylsiloxane medium, permitting removal of the impression with copings embedded for relocation into a laboratory analog model.

When brackets are transferred indirectly, the printed tray operates as a rigid carrier for an inner positioning layer, rather than as the sole flexible transfer matrix, because the polymerized tray resin has a high elastic modulus and does not provide the local deformation needed to release bonded brackets without excessive force. The CAD design derives from a working model on which brackets are placed and then covered with a soft transfer layer, typically a 1.0–1.5 mm silicone duplicating material; the printed tray is then designed over this layer with a uniform shell thickness of 1.5–2.0 mm and occlusal indexing stops that contact the occlusal third of the clinical crown. Since the resin is single-component and requires no mixing, its processing envelope is controlled by temperature and agitation; the material is conditioned to 22–25 °C and printed at 50 µm layer thickness to maintain a smooth inner surface that does not imprint the positioning layer with layer steps. Build orientation is selected so that the bracket slots and the transfer tray long axis are not parallel to the build plate, because layer seams along slot landmarks can create false positioning planes that pass through the soft inner layer and shift individual brackets by 0.2 mm or more. After printing, the carrier is washed in two 97% isopropanol baths for 3 min and 2 min respectively, and post-cured at 40–60 °C for 20–30 min. The tray must be dried thoroughly before the soft transfer layer is inserted; residual solvent in a closed printed shell can migrate into the silicone layer and alter its dimensional stability during adhesive transfer. Cytotoxicity and sensitization are evaluated under ISO 10993-5:2009 and ISO 10993-10:2010; custom tray fabrication records conform to ISO 13485:2016. In use the rigid tray is seated over the bracket-bearing dentition, and a light-cure adhesive is applied to each bracket base; the tray is held under controlled finger pressure until the adhesive reaches gel state, then the soft inner layer is removed first and the rigid printed carrier is lifted off without torquing the brackets out of position. The terminal device is a single-patient transfer tray used once for appliance positioning; it is not indicated for prolonged intraoral wear.

When occlusal clearance is less than 2.0 mm, a dual-arch printed tray must integrate passive venting instead of additional relief

A dual-arch tray for limited interocclusal clearance must satisfy contradictory constraints: it must be thin enough to seat between the opposing arches without forced jaw opening, yet stiff enough not to flex under polyvinylsiloxane injection pressure. When the occlusal clearance measured in the digital articulation is less than 2.0 mm, the tray is designed with an occlusal table thickness of 1.0–1.5 mm, while the buccal and lingual flanges remain at 2.0 mm to provide rigidity. Passive relief is not increased because a thick polyvinylsiloxane reservoir in a tight interocclusal space would cause the mandible to open during seating; instead venting channels are incorporated at 1.0 mm diameter, spaced 4.0–5.0 mm apart across the occlusal table, to release hydraulic pressure and avoid tray float. The resin is a single-component liquid photopolymer, so there is no mixing ratio; the material is conditioned to 22–25 °C and the build is oriented with the occlusal plane angled 15–20° from the horizontal to prevent large unsupported occlusal spans from sagging during printing. A layer thickness of 50 µm is used, and exposure is tuned so that the venting channel diameters do not close due to light penetration; overcure on small hole features can shrink a 1.0 mm designed channel by 0.1–0.2 mm, making it insufficient to release pressure in fast-setting polyvinylsiloxane. After printing, any residual uncured resin inside the venting channels is flushed with a syringe of 97% isopropanol followed by a clean rinse, because retained liquid resin can polymerize during post-cure and seal the channel. Post-curing is performed at 40–60 °C for 20–30 min on a flat support with the occlusal surface upward; if the tray is post-cured with the flanges under load, the thin occlusal web can creep and alter the interocclusal registration by 0.2 mm or more. The dual-arch tray remains a single-use custom device under EU MDR 2017/745 with design controls traceable to ISO 13485:2016. The terminal product is a dual-arch impression tray used with high-tray adhesive and a fast-setting polyvinylsiloxane bite registration or full-arch wash; the printed tray is removed after the material reaches the manufacturer’s set time and is not reused.

In thin anterior stop ledges, post-cure warp is the dominant failure mode

Within the interocclusal record carrier, the anterior stop ledges are the first regions to exhibit post-cure warp because they combine thin cross-sections with load-bearing contact against the incisal edges. The CAD design includes anterior stop ledges at 1.0–1.5 mm height on the maxillary incisor edges and flat posterior shelves with 2.0 mm thickness; these features define the vertical dimension and prevent the mandible from sliding during record material injection. Because the resin is single-component, no mixing ratio is required before printing; temperature conditioning at 22–25 °C and slow rolling minimize bubble entrapment, which is particularly relevant for thin anterior stop ledges where a 0.5 mm bubble can reduce the load-bearing cross-section. Printing is performed at 50 µm layer height on 405 nm DLP equipment, and the carrier is oriented such that the anterior stop ledges do not align with the build plate plane; if they do, peeling force can detach the thin ledges from the plate or create a weak interlayer boundary that fractures when the patient closes into the record material. After washing in 97% isopropanol and drying with oil-free compressed air, the carrier is post-cured at 40–60 °C for 20–30 min and then checked on the patient’s working cast for fit; any rocking around the anterior stop ledges indicates that uneven post-cure shrinkage has occurred and the carrier must be rejected rather than adjusted by grinding, because internal stress relief can cause delayed distortion. Published data for this specific anterior ledge configuration is limited, so each laboratory must validate the post-cure fixture and support pattern with a dimensional capability study before clinical release. The short-term mucosal contact classification is evaluated under ISO 10993-1:2018, and the record carrier is released only after documented process validation under ISO 13485:2016. The terminal device is a single-use interocclusal record carrier used with addition silicone bite registration material or zinc oxide eugenol paste; it is not a definitive occlusal splint and is limited to short-term oral contact during the setting time of the record material.