Should the golden ratio be used in CAD-CAM dentistry?

For unknown reasons, the original term golden ratio (GR) was morphed in dentistry to golden proportion (GP), a term used in current dental literature and recognized by artificial intelligence. The emergence of computer-aided design and computer-aided manufacture (CAD-CAM) technology in prosthodontics poses the question, "Is the GP being used to design anterior milled crowns and digitally assisted dentures?" To perform these tasks, a digital library of tooth forms needs to be present in the software program.

The purpose of this paper was to determine whether the GP is present in exocad tooth arrangements used in the CAD-CAM fabrication of anterior crowns and the most common tooth molds used with AvaDent digitally assisted dentures.

The default library of 17 tooth molds used with the exocad software program for milling anterior crowns was examined to determine whether any of the molds matched the GP of 0.62. Also, the 5 most common Ivoclar and Dentsply denture tooth molds selected for fabricating AvaDent digitally assisted complete dentures were examined to determine whether the GP was present in the tooth arrangements. In addition, a PubMed search of golden proportion was completed to determine whether it is being recommended for use in CAD-CAM dentistry. The search of golden proportion and dental esthetics was completed using the filters: Case Reports, Clinical Trial, Randomized Controlled Trial, and Systematic Review. Additional articles were culled from the reference lists in the articles.

There were 2 early publications proposing the use of the golden proportion in dentistry, 6 studies that examined the relationship of the GP to natural tooth proportions, 7 systematic reviews, and 5 case reports. Measurements of the 17 exocad default tooth molds determined there were 4 molds with a proportional relationship between the width of the maxillary lateral incisor (MLI) relative to the maxillary central incisor (MCI) of 0.61, 0.63, 0.65, and 0.68 (MLI÷MCI), close to the GP of 0.62. All of the others had proportions between 0.73 and 0.87. None of the proportions of the maxillary canine (MCa) to the MLI were close to the GP and ranged from 0.83 to 0.99 (MCa÷MLI). When measurements were made of the 5 most common Ivoclar Blueline and Dentsply Portrait denture teeth molds, it was determined the MLI to MCI proportion did not match the GP and ranged from 0.71 to 0.82. Likewise, the proportion of the MCa to the MLI ranged from 0.72 to 0.80. No studies or systematic reviews supported a relationship between the GP and natural dentitions, yet there were 5 clinical reports published between 2004 and 2025 that recommended the clinical use of the GP, but none involved the use of CAD-CAM dentistry.

The golden proportion is not a valid guide for the design of anterior teeth and is not routinely present in the digital library of tooth molds used for the CAD-CAM fabrication of crowns nor in the most common denture tooth molds selected for use in fabricating 1 brand of digitally assisted dentures.