The authors have declared that no competing interests exist.
The goal of dental restoration is to restore and reconstruct the function, integrity, and morphology of missing tooth structures. At present, dental crowns are usually fabricated by referencing the homonym and adjacent teeth to design the morphology of the restoration, followed by empirical modifications on the restoration morphology. The original morphology of an intact natural tooth, if available, would allow for a balance of the horizontal and vertical forces generated by the surrounding tissues. Otherwise, it is hard for a restoration to reproduce the original tooth morphology. Discrepancies between original tooth morphology and restorations, such as axial over-contour or inappropriate occlusion, may break physiologically established balance, causing patient discomfort or even malocclusion and occlusal diseases. Therefore, to design and fabricate dental restorations with the original tooth morphology could be of great value to oral health. Literature indicates that physiological changes in tooth morphology slowly progress throughout one’s life. We present a hypothetical biomorphic dental restoration design that records the intact tooth morphology of a patient before lesions occur to allow for future design and fabricate of dental restorations. Using a copy of the pre-existing tooth abutment for restoration could result in none or fewer adjustments needed for restoration, and harmony with the surrounding tissues.
Dental restoration is an effective treatment to restore and reconstruct the function, integrity, and morphology of missing tooth structures. At present, technicians or dentists usually fabricate dental crowns by referencing the homonym and adjacent teeth to design the morphology of the restoration. Empirical modifications on the restoration morphology are then made. Thus, it is not surprising that discrepancy exists between the original tooth morphology and that of the restoration. Previous studies have shown that the occlusal surfaces of restorations are about 300 μm higher than the original surfaces
Physiologically, the position of human teeth in the alveolar bone is vertically and horizontally guided by forces generated by the surrounding tissues until they are equal to each other
Many researchers believe that adjusting the occlusal surfaces of the restorations under dynamic occlusion could remove occlusal interference and minimize discrepancies on occlusal surfaces. Mechanical articulators simulate mandibular movements by transferring hinge axis and recorded hinge movements using several parameters and are recommended
We present an opinion to use individual intact tooth morphology information digitally stored before lesions occur for future dental restoration design.
The opinion is based on two key points:
(1) Computer aided design and computer aided manufacturing (CAD/CAM) technology enables us to collect and store individual tooth morphology information with high precision and efficiency to aid in the design and fabrication of dental restorations.
(2) Physiological changes in tooth morphology slowly progress throughout one’s life
We describe this hypothetical design as “biomorphic design”. The biomorphic design first collects healthy individual tooth morphology and stores the information in an individual database using CAD/CAM. When pathological lesions are detected, the biomorphic design extracts the stored individual morphological information of the tooth to fabricate restoration using CAD/CAM copy mode (
However, the biomorphic design is not without limitations. It is suitable for patients with normal occlusion, but it could not be useful for patients with malocclusions or TMD, since the occlusal relationship needs to be adjusted for these patients. The application of the biomorphic design is limited to single crown or three-unit bridge, which accounts for the majority of daily clinical practice of fixed prosthesis. With the accumulation of experience, we expect such thresholds to be defined.
Supported by grant 81130078, 81470773 from National Natural Science Foundation of China and Program for Changjiang Scholars and Innovative Research Team in University (No. IRT13051).