the golden proportion in esthetic treatment planning

The golden proportion in esthetic The golden proportion in esthetic treatment planningtreatment planning

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introductionintroduction

• Beauty is in the eye of the beholder• Perception of beauty in the brain• esthetics – the branch of philosophy dealing

with beauty


Fibonacci numbersFibonacci numbers

• Presented 1202 by Filius Bonacci in text Liber Abaci

• The series is 0,1,1,2,3,5,8,13,21,34,55,89,144…..

• Likened to multiplication of rabbits• Each no. is 1.618 times the previous no.



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Golden sectionGolden section• Known since 550 B.C. to Egyptians

and Greeks• Marvellous as it is perceived as

beauty, harmony and balance• Static symmetry vs. Dynamic

symmetry• 1.618/1 = 0.618 referred to as Ф after

phidias• Kepler in 1600 callled it as divine

proportion• Key to normal morphology• Natural law of growth of animals and

plants


Clinical application in dentistryClinical application in dentistry

• width of 1┘: 1┐= 1.618• Lower incisors width :

upper intercanine width = 0.618

• Found in people with most attractive smiles, faces and most graceful figures

• Fundamental component of major biologic plan


Golden rectangleGolden rectangle• Base of 1.0 and

perpendicular side 1.618• E.g. playing cards, credit

cards, picture frames, 3”* 5” postcards

• Golden triangle, pentagon, spirals

• Dynamic: seem to display some sort of life, animation

• Golden divider by Robert M. Ricketts


Why it worksWhy it works

• Face, jaws and teeth as geometric structures present more esthetics if they align more with GP

• Referred to as golden to each other• Smile analysis by several investigators

confirm presence of GP


CompositionComposition

• Study of objects made visible by contrasts in color , line and texture

• Components • Unity : oneness, ordering of parts of a

composition to give the individual a total, whole effect

• Static dynamic• Regular geometry logarithmic spirals• Passive, inert dynamic, living


• Cohesive elements : tend to unify a composition• Repetition of shape, line and

color• Unfortunately appear static or

dead• Arrangement of maxillary ant.

Teeth to a circle

• Segregating elements: introduce unity with variety• Hogarth’s line of beauty • introduced to teeth arrangement


DominanceDominance• One shape, color should

dominate • Others subservient• E.g the maxillary central incisor

is the most dominant tooth by virtue of it’s visible size

• Not maxillary cuspid as only mesial side is visible

• Mouth is the dominant feature of the face


Proportion Proportion

• Golden proportion is ideal guide• Disadvantages

• Unfortunately applied unilaterally • Malaligned teeth, overlap, diastemas• Requires calliper and calculator


Golden percentagesGolden percentages

• Calculated as total sum / individual ratio i.e. 0.618+1+1.618+1+0.618=6.472/ individual ratio

• 10%-15%-25%-25%-15%-10%• Does not depend upon lateral incisors

only but the individual tooth’s contribution to whole

• Teeth with identical width generate identical %

• Asymmetry clearly identifiable and quantifiable


Smile analysisSmile analysis

• Repeatable, measurable objective principles can be applied o improve esthetics

• Consider the following factors in the dentofacial analysis• Upper lip position – high, average or low• Upper lip curvature• Parallelism of maxillary incisal curve with lower lip• Relation between maxillary anteriors and lower lip• Number of teeth displayed in a smile• Midline relation of the central to the philtrum


• Interpupillary line to midline of face• Midline of teeth to midline of face• Lip symmetry• Profile ( influences dominance given to

centrals)• The negative space• Buccal corridor


Dental analysisDental analysis

• Width and height of existing teeth• Proportion• Parallelism• Axial inclination, rotation, malposition• Gingival characteristics


Smile designSmile design

• Age, sex and personality• Oral health• Three factors effecting smile design

• Symmetry across midline• Anterior or central dominance• Regressive proportion


Treatment planningTreatment planning

• Step 1 – establish facial symmetry and midline• Interpuppilary line // horizon• Placement of midline at exact center – artificial• Eccentric unexaggerated midline – natural illusion• Maxillary midline and facial /labial frenum midline –

70.4%• Do not use mandibular midline• Stable positioning without leanings to left or right


• Step 2 – record the highest lip line • Height of upper lip at full smile

• Length of centrals• Amount of visible gingiva • Photographs or manual

• Ideal smile, gummy smile or long lip smile• Obvious gingival asymmetry noted• Postion of lateral incisor


• Step 3 – take photographs• As viewed from the front• Lips retracted• Horizontal frame should // interpupillary line• Or vertical margin // the facial midline• 8” from centrals , 1: 2 magnification


Grid analysis systemGrid analysis system

• Given by CK Naylor• Incorporation of midline axis, incisal plane,

highest lipline, proportionate contact areas forms a grid

• Provides a method of demonstrate variations from esthetic arrangement of anterior teeth


• Step 4 – draw the lines on the photograph• aim to coincide with idealized positions of• Incisal plane- // upper or lower frame at the position of

idealized incisal edge• Incisal edge- cornerstone and set to correct level

determined for the pt’s smile• Visibility at rest and lip mobility• Incorporated to grid and verified in mock up

• Highest lip line drawn • Midline axis drawn perpendicular to the incisal plane


• Proportionate placement of contact areas• Cental incisor to lateral incisor establishes the

former as dominant factor in the composition• Repeated proportion by Lombardi between CI, LI

and canines• Most followed is golden proportion

(1/1.618=0.618)• CI= 9mm → LI = 9*0.618= 5.56mm• Golden percentages can be used


RED ProportionRED Proportion

• Recurring esthetic dental proportion• Basically implies not to follow the 62% proportion• States that proportion of the successive widths of the teeth

as viewed from the frontal should remain constant as one moves distally dentist can define his own RED proportion

• Several studies have reported mean proportions of 66-78% for LI: CI


• Step- 5 treatment phase • Carried out in mouth based on the grid system• Final result visualized with mock up or

provisionals• Conventional therapy constituted after patient’s

consent.


ConclusionConclusion

• Golden proportion ids the starting point in smile design

• Strict adherence to it is questionable but it serves as useful tool for initial evaluation of dominance and proportion



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the golden proportion in esthetic treatment planning

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