3D printed presurgical passive nasoalveolar molding designed with facial balance and the occlusal plane for cleft lip and palate infants
This study demonstrates that a novel 3D-printed presurgical nasoalveolar molding protocol, designed using integrated facial and alveolar data to address vertical and horizontal discrepancies, effectively improves facial symmetry and alveolar alignment in infants with unilateral cleft lip and palate without requiring CT imaging.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
When a baby is born with a cleft lip and palate, the gap in the upper jaw is not just a missing piece of skin; it is a structural imbalance where the two sides of the mouth have drifted apart and often up or down relative to each other. Before surgeons can stitch the lip closed, orthodontists often use a custom-made plastic plate inside the baby's mouth to gently push the separated gum ridges closer together. This process, known as presurgical nasoalveolar molding, helps align the teeth and shape the nose, making the eventual surgery easier and the final look more symmetrical. However, a persistent challenge has remained: while these plates are excellent at bringing the sides together horizontally, they often fail to fix the vertical height difference between the two sides of the jaw. If one side of the jaw sits higher than the other, it can tilt the entire bite and the face, leading to complex problems that might require major surgery later in life.
A team of researchers at The University of Osaka has developed a new way to address this specific vertical imbalance using digital technology. Instead of relying solely on physical models of the baby's mouth, they created a unified digital map that combines a 3D scan of the baby's face with a 3D scan of the inside of the mouth. By merging these two views, they could see exactly how the jawbone sat in relation to the rest of the skull, a relationship that is difficult to judge without exposing a newborn to radiation from a CT scan. Using this combined map, the team performed a virtual surgery on the computer. They digitally moved the separated jaw segments up, down, left, and right until they achieved a perfectly balanced position relative to the face. Based on this ideal digital plan, they then designed and 3D printed a series of custom plastic plates. These plates were worn by the infants in stages, with new ones replacing the old ones every few weeks to gradually guide the jaw into the correct position before the lip surgery took place.
The study followed twelve infants with this condition, measuring their faces and jaws before treatment began and again just before their lip reconstruction surgery. The results showed that this digital approach successfully corrected the vertical height differences. Before treatment, the jaw segment on the cleft side sat significantly higher than the other side, particularly at the canine tooth area and the back of the upper jaw. After the treatment, these height differences were reduced by more than half, bringing the two sides into much better alignment. The treatment also significantly improved the horizontal position of the jaw, bringing the cleft side closer to the center, and corrected the tilt of the upper lip. While the treatment was very effective at fixing the up-and-down and side-to-side alignment, the researchers noted that it did not significantly change how far forward or backward the jaw segments sat.
The researchers found that the cleft side of the jaw was naturally displaced in three directions: it was higher, further to the side, and further back than the healthy side. Their digital simulation allowed them to plan a precise correction for the height and side-to-side position, which the physical plates then executed. The study confirmed that the cleft width shrank dramatically, from an average of nearly 12 millimeters down to about 3 millimeters, without squeezing the entire jaw arch too tightly. Crucially, the tilt of the mouth corners, which often follows the uneven jaw, also improved significantly, moving from a noticeable tilt to a nearly level position. The team suggests that by fixing these vertical and horizontal imbalances early, the need for complex corrective surgeries in adolescence might be reduced, and future bone grafting procedures could be easier to perform.
This work represents a shift in how these early treatments are planned. Previously, the design of these molding plates was based only on the shape of the teeth and gums, ignoring how those parts sat within the larger structure of the face. By integrating the facial skeleton into the planning process, the researchers were able to correct a type of deformity that was previously difficult to address without invasive imaging. The study did not compare this new method directly against the old method in a side-by-side trial, so the full extent of its superiority over traditional techniques remains to be seen in broader studies. However, the data clearly shows that this digital, simulation-guided approach can effectively realign the jaw segments relative to the face, offering a promising path toward better symmetry for infants born with cleft lip and palate.
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