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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 13  |  Issue : 5  |  Page : 778-782  

Analysis of geometric proportions on maxillary anterior teeth for esthetic smile design: An In vivo study


1 Department of Prosthodontics, Indira Gandhi Institute of Dental Science, Nellikuzhi, Kerala, India
2 Department of Prosthodontics, Mar Baselios Dental College, Thrikkariyoor, Kerala, India
3 Department of Prosthodontics, Malabar Dental College, Malappuram, Kerala, India
4 Private Practitioner, Sreeragam, Ernakulam, Kerala, India
5 Department of Oral and Maxillofacial Surgery, Al Azhar Dental College, Thodupuzha, Kerala, India
6 Department of Orthodontics, Indira Gandhi Institute of Dental Science, Nellikuzhi, Kerala, India

Date of Submission06-Dec-2020
Date of Decision11-Dec-2020
Date of Acceptance18-Dec-2020
Date of Web Publication05-Jun-2021

Correspondence Address:
Pinky Varghese
Department of Orthodontics, Indira Gandhi Institute of Dental Science, Kothamangalam, Nellikuzhi, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jpbs.JPBS_808_20

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   Abstract 


Background and Objectives: The maxillary central incisor is the dominant element of anterior dental composition and hence should be restored or replaced with proper proportion of width and length for better aesthetic results. However, the literature is not clear regarding verifiable guidelines for the determination of proportions of the teeth. The aim of this study was to investigate the existence and suitability of Golden Rectangle, Recurring Aesthetic Dental Proportion, and Golden percentage between the widths of maxillary anterior teeth in individuals with natural dentition, with the aid of digital photographs and computer analysis. Material and Methods: Frontal full-face digital photographs of the subjects (in smile) were made under standardized conditions using a digital camera and a tripod stand was used to place and orient the camera in the standardized position (camera was positioned 1 meter away from the patient; and the lens of the camera was adjusted at the patients' lip level). Imaging software (Adobe Photoshop CS5; Adobe Systems, Inc, San Jose, Calif.) was used to mark the anatomic landmarks and to digitally analyze the photograph. The entire process of proportion analysis was done by a single observer. Results: The RED proportion was not found to exist between the six maxillary anterior teeth. The values suggested in the golden percentage were not applicable on the subjects of this study. However, a slight modification of these percentages can be adopted taking into consideration the ethnicity differences of the subjects in this study. The values obtained were 24%, 15%, 11% in males and 23%, 15%, and 11% in females. Golden rectangle concept can be used for choosing dimensions of maxillary central incisors which are esthetically pleasing. Conclusion: RED proportion is an unsuitable methods to relate the successive widths of the maxillary anterior teeth. The golden percentage theory seems to be applicable to relate the successive widths of the maxillary anterior teeth if percentages are adjusted taking into consideration the ethnicity of the population. Golden rectangle concept is suitable for choosing dimensions of maxillary central incisors which are esthetically pleasing.

Keywords: Analysis, esthetic smile, geometric proportions, maxillary anterior teeth


How to cite this article:
Varghese P, Cherian B, Sukumaran B, Anu S, Jacob BM, Raja VV. Analysis of geometric proportions on maxillary anterior teeth for esthetic smile design: An In vivo study. J Pharm Bioall Sci 2021;13, Suppl S1:778-82

How to cite this URL:
Varghese P, Cherian B, Sukumaran B, Anu S, Jacob BM, Raja VV. Analysis of geometric proportions on maxillary anterior teeth for esthetic smile design: An In vivo study. J Pharm Bioall Sci [serial online] 2021 [cited 2021 Jul 29];13, Suppl S1:778-82. Available from: https://www.jpbsonline.org/text.asp?2021/13/5/778/317699




   Introduction Top


Smile, which shows a range of emotions with the structure and movement of the teeth and lips, is used to determine how well a person performs in society.[1] Creating geometric or mathematical proportion to relate the successive width of anterior teeth has become one of the important aspects of esthetic dentistry. Golden proportion, golden percentage and recurring esthetic dental (RED) proportion, and golden rectangle are some of the theories related in this field.[2]

However, recent studies show that golden proportion was not found to exist between the widths of the maxillary anterior teeth in individuals who have an esthetic smile.[3] Ward, who suggested the RED proportion, based his suggestion on his study in which he described RED proportion as the proportion of the successive width of the teeth remaining constant, when progressing distally from the midline.[4] Snow[5] considered individual tooth width as a percentage of the total apparent width of the six anterior teeth. He proposed the golden percentage, where the proportional width of each tooth is canine 10%, lateral 15%, central 25%, central 25%, lateral 15%, and canine 10% of the total distance across the anterior segment, to receive an esthetically pleasing smile.[5] Many dentists were able to find the proportions of the central incisor very beautiful, but they were not been able to find a golden proportion relationship between the width and height. The problem was solved when Dr. Stephen Marquardt, an eminent Oral surgeon in California, who proposed golden rectangle discovered that, “The height of the central incisor is in the golden proportion to the width of the two central incisors.”[6]

The purpose of the present study is to investigate the existence and suitability of RED proportion and golden percentage and golden rectangle between the widths of maxillary anterior teeth in individuals with natural dentition, with the help of digital photographs and computer analysis.


   Materials and Methods Top


The present study is conducted in the Department of Prosthodontics, MarBaselios Dental College, Kothamangalam. Full-face digital images of subjects in smile will be made, with the subject in a seated position. It was decided to conduct the study on 150 subjects, comprising both male and female, selected from the students and patients of the outpatient department of Mar Baselios Dental College. Approval from the institutional research committee was obtained, and informed consent was taken from each subject. The investigation was carried out in the following manner:

Selection of subjects

The following inclusion criteria were observed for the selection of subjects for the study:

  1. Age between 18 and 25 years
  2. No history of congenital conditions or trauma affecting facial form and appearance
  3. No history of orthodontic treatment
  4. No missing maxillary anterior teeth
  5. No prosthetic maxillary anterior teeth
  6. No interdental spacing or crowding in maxillary teeth.


Materials used for the study

  1. Digital camera (NIKON D40X digital SLR camera, 10.2 Megapixel; Nikon Corporation, Japan)
  2. Tripod stand-BENRO-T660EX (Made in China)
  3. Imaging software (Adobe Photoshop© CS5, Adobe Systems Inc., San Jose., Calif., USA).


Method of taking photographs

Demographic information such as age and gender of each student was recorded. The digital camera (NIKON D40X digital SLR camera, 10.2 Megapixel; Nikon Corporation, Japan) was mounted on a tripod stand with a standardized focus and at a standardized distance of 1 m from the subject. In this position, the focal plane was 450 mm from the soft tissue with the camera lens focused on the lips. The lighting conditions remained same for the study procedure. Subject was asked to sit on a chair with their Frankfort horizontal plane parallel to the floor and the mid-sagittal plane of the head was aligned with the center of the camera lens. To standardize the views, the protocol for photographic presentation of the American Academy of Cosmetic Dentistry[7] was used as a guide. The following camera settings were used: 1/200 shutter speed, f/22 aperture, ISO 200 sensitivity. A digital camera with an APS-C size sensor (22.2 mm × 14.8 mm) was used. The subject was asked to smile and the image was captured during the smile. The images were then downloaded to a personal computer. All the measurements were measured with the help of the software Adobe Photoshop 5, by one investigator. Since angulations of a tooth make its visible width different from its actual width, we measured the visible width of the teeth.

Once the measurements are made, calculations were made according to each of the above mentioned theories. The data were statistically analyzed using paired Student's t-test (level of significance P ≤ 0.05).


   Results Top


Recurring esthetic dental proportion

With respect to RED proportion, the results of this investigation [Table 1] and [Graph 1] showed that, for females on the right side, the ratio of the width of maxillary lateral incisors to the width of central incisors is 66.87% and the ratio of width of canine to width of lateral incisor is 71.58%. For females on the left side the ratio of the width of maxillary lateral incisors to the width of central incisors is 66.3% and the ratio of width of canine to width of lateral incisor is 70.8%.



For males on the right side [Graph 2], the ratio of the width of maxillary lateral incisors to the width of central incisors is 63.3% and the ratio of width of canine to width of lateral incisor is 69.3%. For males on the left side, the ratio of the width of maxillary lateral incisors to the width of central incisors is 63.1% and the ratio of width of canine to width of lateral incisor is 68.78%.



Golden percentage

In females as for using golden percentage theory to correlate the six anterior teeth, the result of the present investigation [Graph 3] suggests that the mean value for golden percentage for right central incisor is 23.4%. The mean value for right lateral incisors is 15.6%. With respect to golden percentage of canines, the result of this study showed a mean value of 11.1%. Values of central incisor, lateral incisor, and canine are not in agreement with value suggested by Snow.



For females on the left side, the mean value for golden percentage for left central incisor is 23.4%. The mean value for left lateral incisors is 15.4%. With respect to golden percentage of left canines, the result of this study showed a mean value of 10.8%. The values for lateral incisor was in agreement with those suggested by Snow,[5] who recommended a value of 15 as the golden percentage for lateral incisor

For males on the right side [Graph 4], the mean values for golden percentage for right central incisor is 24.2%. The mean value for right lateral incisors is 15.3%. With respect to golden percentage of right canines, the result of this study showed a mean value of 10.5%. The values for right lateral incisor was in agreement with those suggested by Snow,[5] who recommended a value of 15 as the golden percentage for lateral incisor.



For males on the left side, the mean values for golden percentage for left central incisor is 24.3%. The mean value for left lateral incisors is 15.3%. With respect to golden percentage of left canines, the result of this study showed a mean value of 10.5%. The values for lateral incisor was in agreement with those suggested by Snow,[5] who recommended a value of 15 as the golden percentage for lateral incisor.

Golden rectangle

The data collected from 150 subjects (65 males, 85 females) [Graph 5] revealed that the range of combined width to length ratio of clinical crown of maxillary central incisors was 1.6 for females and 1.59 for males. Statistically no significant difference was observed between suggested value (1.6) and that obtained in the current population. As the values are in agreement with values suggested by Marquardt, golden rectangle is applicable in the population.




   Discussion Top


”Esthetics” is a major concern in modern dentistry. However, natural esthetics which plays the dominant role is not a subject of choice, but a necessity. Modern concept has helped to alleviate many of the sore spots from the past. Although more advances in techniques and materials are being made in prosthodontics, still no accurate method for the selection and arrangement of the maxillary anterior teeth is available to the dentist. The selection of teeth is more of an “artistic” component which is a paradigm of clinician's skill's, technician's flair, and patient's acceptance. According to Kirtley, 2008,[8] the most dramatic artistic effect is the creation of proper proportion. We know that the most influential factors in a harmonious anterior dentition are the size, shape, and position of the maxillary central incisors.

The size and morphology of maxillary central incisors are the key determinants in esthetically accepted cases.[9] In traditional methods, extracted teeth were used for measuring tooth sizes; however, at present, photographs are used for this purpose instead of extracted teeth. This study evaluated visible widths of maxillary centrals, laterals, and canines and the lengths of central teeth. The measurements were compared with RED proportion and golden percentage.

Previous studies were done to check existence and suitability of RED proportion proved that it cannot be taken as a reliable guideline for selecting maxillary central incisors. However, since ethnic differences exist between different populations, universal application of the previous research work is possible only when it is studied in other populations also.[10] Hence, the present study was an attempt to analyze existence and suitability of RED proportion and golden percentage in Kerala population.

In the present study, the ratio between central and lateral incisors and between lateral incisor and canine is not constant. The value 66% in females and 63% in males which was the ratio of the width of maxillary lateral incisors to width of central incisors is in agreement with the 60%–80% RED proportion suggested by Ward,[4] and the mean proportion suggested by Ali Fayyad et al,[11] which was between 63% and 78%. In the current study, lateral incisors are slightly narrower whereas the lateral incisors are slightly wider in the 70% RED proportion. The value 70.8%–71.5% in females and 68.7%–69.3% in males, which was the ratio of the width of canine to the width of maxillary lateral incisors, is in agreement with the 60%–80% RED proportion. However, the ratio between central and lateral incisors and between lateral incisor and canine is not constant in males as well as females, as suggested by Ward.[4] The overall results showed that RED proportion did not seem to exist in the current population.

For males, golden percentage of canines is 10.5 on the right side and 10.5% on the left side for males. These figures are slightly higher than those suggested by Snow,[5] who recommended a golden percentage value of 10% for canines. In general, it appears the width of central incisors is slightly smaller and the width of canines is slightly larger than those suggested by the golden percentage theory. A value of 23% in females and 24% in males for centrals, 15% for laterals, and 11% for canines can be adopted as these percentages are more applicable to natural dentition. Minor variations in the values obtained in this study, as compared to previous studies,[1] may be attributed to the ethnic difference of the subjects that were chosen in the present study. Owens et al.[10] measured the width of maxillary central incisors in several racial groups and noted variation in most of them, with males having wider central incisor than females.

Golden rectangle

As for the golden rectangle, the ratio of combined width of central incisor with average height of central incisor is 1.59 for males and 1.6 for females, which supports golden rectangle. Marquardt[6] found the ratio of combined width to length 1.618. Sterrett et al.[12] also observed the same results as that of Marquardt. Sterrett[12] et al. also performed same kind of study using the maxillary central incisors width to length ratio. Both of them found gender variation with males having greater width and length as compared to females in different racial groups. In the present study, no statistically significant differences were seen between two genders [Graph 5]. On observation, it was found that individuals with higher width to length ratio had broader or square central incisors while individuals with lower width to length ratio had longer and narrower central incisors. Rather than depending on a single ratio, such as the golden proportion or RED proportion, golden percentage reflecting harmony among tooth lengths should be considered when striving to produce a satisfactory appearance.[13],[14]


   Conclusion Top


The RED proportion was not found to exist between the six maxillary anterior teeth. The values suggested in the golden percentage were not applicable on the subjects of this study. However, a slight modification of these percentages can be adopted taking into consideration the ethnicity differences of the subjects in this study. The values obtained were 24%, 15%, 11% in males and 23%, 15%, and 11% in females.[10] Golden rectangle concept can be used for choosing dimensions of maxillary central incisors which are esthetically pleasing

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

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Bhuvaneswaran M. Principles of smile design. J Conserv Dent 2010;13:225-32.  Back to cited text no. 1
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Lombardi RE. The principles of visual perception and their clinical application to denture esthetics. J Prosthet Dent 1973;29:358-82.  Back to cited text no. 2
    
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Preston JD. The golden proportion revisited. J Esthet Dent 1993;5:247-51.  Back to cited text no. 3
    
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Ward DH. Proportional smile design using the recurring esthetic dental (red) proportion. Dent Clin North Am 2001;45:143-54.  Back to cited text no. 4
    
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Snow SR. Esthetic smile analysis of maxillary anterior tooth width: The golden percentage. J Esthet Dent 1999;11:177-84.  Back to cited text no. 5
    
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Marquardt SR. Dr. Stephen R. Marquardt on the Golden Decagon and human facial beauty. Interview by Dr. Gottlieb. J Clin Orthod 2002;36:339-47.  Back to cited text no. 6
    
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Boyd JG. AACD accreditation process. Tex Dent J 2005;122:976-9.  Back to cited text no. 7
    
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Kirtley GE. The art of a beautiful smile. J Cosmetic Dent 2008;24:122-31.  Back to cited text no. 8
    
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Wolfart S, Thormann H, Freitag S, Kern M. Assessment of dental appearance following changes in incisor proportions. Eur J Oral Sci 2005;113:159-65.  Back to cited text no. 9
    
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Owens EG, Goodacre CJ, Loh PL, Hanke G, Okamura M, Jo KH, et al. A multicenter interracial study of facial appearance. Part 1: A comparison of extraoral parameters. Int J Prosthodont 2002;15:273-82.  Back to cited text no. 10
    
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Ali Fayyad M, Jamani KD, Agrabawi J. Geometric and mathematical proportions and their relations to maxillary anterior teeth. J Contemp Dent Pract 2006;7:62-70.  Back to cited text no. 11
    
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Sterrett JD, Oliver T, Robinson F, Fortson W, Knaak B, Russell CM. Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man. J Clin Periodontol 1999;26:153-7.  Back to cited text no. 12
    
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Mahshid M, Khoshvaghti A, Varshosaz M, Vallaei N. Evaluation of “golden proportion” in individuals with an esthetic smile. J Esthet Restor Dent 2004;16:185-92.  Back to cited text no. 13
    
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Shirinzad M, Ahmady B. Evaluation of golden proportion of upper anterior teeth in dental student of Hamadan Dental School. J Mashhad Dent Sch 2004;384:255-61.  Back to cited text no. 14
    




 

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