positive progress. There was speculation near the end of the discussion section regarding additional parameters, such as tooth inclination and arch shape, and it is recom- mended the authors examine the 1996 4 and 1995 3 papers, respectively. Future studies providing a detailed description of the interproximal form of the incisor teeth may improve accuracy as various forms may impact on overbite and overjet. Understanding dental arrangements is desirable for all orthodontists. Using multivariable mathematical models allows a dynamic comprehension of possible interactions between variables. The research of Beygelman et al is another stride toward better understanding orthodontic occlusion. Mark Cordato Bathurst, New South Wales, Australia Am J Orthod Dentofacial Orthop 2020;158:313 0889-5406/$36.00 Ó 2020 by the American Association of Orthodontists. All rights reserved. https://doi.org/10.1016/j.ajodo.2020.05.008 REFERENCES 1. Neff CW. Tailored occlusion with the anterior coefficient. Am J Orthod 1949;35:309-13. 2. Bolton WA. Disharmony in tooth size and its relation to the analysis and treatment of malocclusion. Angle Orthod 1958;28:113-30. 3. Cordato MA. A Simple mathematical study of anterior dental relations: part I. Aust Orthod J 1995;13:249-52. 4. Cordato MA. A mathematical study of anterior dental relations: part II, incisor and canine overjet. Aust Orthod J 1996;14:143-9. 5. Tuverson DL. Anterior interocclusal relations. Part I. Am J Orthod 1980;78:361-70. 6. Sangcharearn Y, Ho C. Effect of incisor angulation on overjet and overbite in Class II camouflage treatment. A typodont study. Angle Orthod 2007;77:1011-8. 7. Cordato MA. A simple mathematical study of anterior dental relations. Part III: Incisor and canine overbite. Aust Orthod J 1998;15:75-84. Authors' response T hank you for your letter regarding our article. We appreciate your comments and the references to your articles 1-3 that evaluated the anterior dental occlusion in detail. Unfortunately, we omitted these references from our paper, for which we apologize. We agree that the anterior dental occlusion depends on many factors, not only the mesiodistal tooth width as used in the Bolton analysis 4 or the buccolingual thickness that we included in our study, as you have done before. 3 Some additional factors are overjet 2 and overbite, 3 which we did not address. All these factors are associated with one another, as you have described in your articles. In addition, many other features are important in determining the anterior occlusion, such as incisor angulation and arch shape. Some features that play a role in the anterior occlusion are hard to capture and include in a mathematical model, such as maxillary incisor crown shape. As you stated, our study added only 1 factor (tooth thickness or buccolingual width) to the Bolton ratio to improve its accuracy. We agree that more factors are at play, but at this time, it is difficult to combine all of them into 1 simple mathematical model that can be used in a clinical situation. The future may be 3-dimensional mathematical renderings of each patient's anterior dental occlusion, taking into account tooth anatomy, overjet, overbite, angulation, and many other patient-specific features. Until then, clini- cians need to understand the limitations of the Bolton analysis and be aware of the multitude of interrelated variables that influence the anterior occlusion. Clinicians need to be prepared to make adjustments to their treat- ment to obtain the ideal occlusal result for each patient. Anne-Marie Bollen Yelena Akselrod Beygelman Roozbeh Khosravi Mohamed Masoud David Turpin Seattle, Wash Am J Orthod Dentofacial Orthop 2020;158:313 0889-5406/$36.00 Ó 2020 by the American Association of Orthodontists. All rights reserved. https://doi.org/10.1016/j.ajodo.2020.06.009 REFERENCES 1. Cordato MA. A simple mathematical study of anterior dental rela- tions: part I. Aust Orthod J 1995;13:249-52. 2. Cordato MA. A mathematical study of anterior dental relations: part II, incisor and canine overjet. Aust Orthod J 1996;14:143-9. 3. Cordato MA. A simple mathematical study of anterior dental relations. Part III: incisor and canine overbite. Aust Orthod J 1998;15:75-84. 4. Bolton WA. Disharmony in tooth size and its relation to the analysis and treatment of malocclusion. Angle Orthod 1958;28:113-30. Botulinum toxin for gummy smile correction E ighteen years after my initial undertaking in 2002, searching for a minimally invasive, nonsurgical treatment alternative using botulinum toxin (Botox; onabotulinumtoxin A) for gummy smile correction, 1,2 I now enjoy reading the article by Cengiz et al (Cengiz AF, Goymen M, Akcali C. Efficacy of botulinum toxin for treating a gummy smile. Am J Orthod Dentofacial Orthop 2020;158:50-8). The novel concept presented in 2002 was accepted positively by a few orthodontic Readers' forum 313 American Journal of Orthodontics and Dentofacial Orthopedics September 2020  Vol 158  Issue 3