The Influence of Labio-lingual and Mesio-distal Anterior Tooth Dimensions on Inter-arch Relationships: A Modified Anterior Bolton Analysis

Yelena Akselrod Beygelman
Chair of the Supervisory Committee:
Anne-Marie Bollen, Graduate Program Director
Department of Orthodontics

Introduction: Tooth size and morphology of anterior teeth influence inter-arch relationships. The Bolton analysis uses tooth width to calculate a sum of mandibular to maxillary tooth widths ratio necessary for proper occlusion. Several parameters not factored in the Bolton analysis influence occlusion such as tooth thickness. This study sought to use 3D modeling to develop and assess a tooth size analysis that encompasses labio-lingual thickness as well as mesio-distal width of anterior teeth.

Methods: The role of tooth thickness in inter-arch relationships was studied using simulations in a 3D modeling software (SuresmileTM). To develop a new chart of inter-arch ratios based on tooth thickness, a series of simulations were produced with varying tooth thicknesses and widths. The new ratios were evaluated on records from 50 patients.

Results: Findings from the simulations suggest that the ideal tooth thickness remains approximately 2mm if the overall tooth width of the dentition increases and the inter-arch anterior ratio is maintained. The thickness-adjusted anterior mandibular to maxillary tooth ratio ranges from 0.70 to 0.79 depending on the tooth thickness. This thickness-adjusted ratio provides a superior prediction for the sum of anterior tooth width compared to the Bolton analysis.

Conclusions: Tooth thickness does affect inter-arch tooth width ratios and anterior occlusion. A thickness-adjusted ratio can be used to more accurately predict anterior tooth dimensions necessary to achieve proper occlusion.

Bio: Yelena is originally from Ukraine, and moved to the states at a young age. She grew up in Bellevue, Washington and completed her undergraduate education in Biology at the University of Washington. She then moved to sunny Los Angeles to attend the University of California, Los Angeles for her dental degree, where she met her husband, Leo. Keeping up the Team 1 tradition, she got married in the first year of her orthodontic residency program. Yelena is immensely fortunate to have had the opportunity to return home to the Pacific Northwest to pursue orthodontics at the University of Washington. She is forever grateful to the wonderful faculty for sharing their experience, and for their endless support. She would especially like to thank her loving family and husband, who have been by her side through this journey. Three years have flown by, and she will miss the UW Ortho family. Yelena is looking forward to staying in Seattle after graduation and starting her orthodontic career.