Aesthetics in orhtododntics/ dental implant courses by Indian dental academy

Aesthetics in orthodontics

INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com

Introduction Jackson’s triad : Aesthetic Stability Function

Riedel : Beauty Utility Stability www.indiandentalacademy.com

The Enigma Of Beauty “We Know it when we see it – or so some think” What is beautiful is good – Plato Beauty is truth, truth is beauty – John Keats More profound than truth itself – Anatole France www.indiandentalacademy.com

Plastic surgeons may define it in terms of “high cheek bones and stronger jaw”. Science pronounces beauty as a strategy that says “ I’m healthy and fertile . I can pass on your genes. Beauty celebrates, it matters, and it resides in the brain circuitry of the beholder and less so in the eye – Don Symons (UCSB)

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 It could be macabre  It could be deadly  And it is costly – 6 billion on fragrance, 6 billon on make up, 8 billion and hair and skin, a billion on nails , 20 billion on diet products – 1999 US alone.

 It is a fundamental evolutionary strategy – Victor Perret (NMSU)

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“It has been said that beauty is in the eye of the

beholder, but a thing is said not to be truly beautiful until it arouses the senses to an emotional level of pleasure. This level of perception is not in the cognitive part of the brain (neocortex) but is thought to be located within the subconscious or primitive portion of the brain referred to as the reptilian complex or the limbic system. The limbic system is thought to contain the instincts.� Robert M Ricketts

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It is considered capable of conditioned reflex so that, in the appreciation of beauty and art, a factor of discipline and previous exposure exists.

However, with the capacity to select beauty by instinct and with the natural laws favoring economy of tissue and energy, there probably is a natural connection with the sensation of beauty and efficiency. Mankind's mind is attracted to precision; hence, survival and improvement in the species biologically. This probably occurred together with the development of the large brain in man and the ability to think and reason.

Robert M Ricketts www.indiandentalacademy.com

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ď‚Š Phillip etal (1993) assessed the profiles and noted that lay persons judged Class I profiles as most attractive compared to Class II (non surgical) and Class II surgical were judged least attractive. ď‚Š Sociologists and psychologists have shown that the perception of appearance , particularly the face affects mental health and social behavior, with significant implications for educational and employment opportunities and mate selection. ď‚Š Kleck and Rubinstien found that attractive individuals elicit more smiles and are looked at longer than less attractive people. www.indiandentalacademy.com

ď‚Š Rutzen (1973) studied 250 patients 5 years after completion of orthodontic therapy and compared then with 67 subject who had received no treatment for diagnosed malocclusion. Those treated scored significantly more positive for their assessment and also achieved a higher level of occupational status even though the groups did not differ in social class or status.

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The esthetic heritage ď‚ŠMan, subconciously, has been aware of facial esthetics for a very long time ď‚ŠThe cave paintings of southern France (35000 yrs ago) provide ample evidence of his esthetic awareness

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 Art and esthetic awareness flourished during the early days of the Egyptian civilization and it reflected the idealized proportion of the face dictated by the ruling class.  They exhibited a round broad face with a sloping forehead, weak brow ridge, prominent eyes, evenly contoured nose , thickened lips and a mild yet positive chin.  Yet this showed ideal, archeologist have shown that the general public showed a large amount of bi maxillary prognathism, taking into consideration that the Egyptians were primarily a mix of African Negroid and Caucasoid Asians. www.indiandentalacademy.com

ď‚ŠTowards the end of the middle kingdom and the start of the new kingdom the idealized facial features shifted to more narrower face and high brows and elaborate make ups.

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ď‚Š After Egyptians, the Greeks emerges as the first to express sensitively the qualities of facial expression. ď‚Š Often rules or Canons were set forth for ideal bodily proportions and harmonious anatomic relations in human representation ď‚Š The Greek face is oval and slightly tapering towards the chin and the basic facial features appear to be treated identically. www.indiandentalacademy.com

 The face shows an anteriorly prominent forehead. Also characteristic is the straight sweep fro the forehead to the nose tip with a faint concavity at the root of the nose  The lower face is seen to be well proportioned and the mouth is framed by an undulating upper lip (cupids bow) and a slightly lower lip roll.  Between the lower lip and the convex fleshy chin is the well defined mentolabial sulcus www.indiandentalacademy.com

 This classic Greek features appealed to many early orthodontists including Angle through his association with the artist Wuerpel and considered Apollo and Aphrodite as paragons of facial beauty.  Though they were acutely aware that one standard ideal cannot be attributed to all individuals  Also later Wilson totally dismissed the Greek aesthetics saying that is showed a retrognathic lower face.  Also whether the statues represented the actual facial form of the common people of those times is questionable. www.indiandentalacademy.com

 After the Greeks the Romans entered the scene and advancement in Greek and Roman architecture were made though there wasn’t any new concepts developing.  The Romans were depicted faithfully in their true form with variations in proportions and facial features.  At the end of the 4th century the Roman period had come to an end and the Dark Age had begun, when Europe was gripped in a religious zeal  Almost all medieval descriptions of the lower face valued a small inconspicious mouth with thin red lips and even small teeth www.indiandentalacademy.com

ď‚Š The Renaissance period heralded the return of the realistic aesthetic values and the names of Michelangelo, Raphael, Leonardo Da Vinci, and other renaissance artists became noted. ď‚Š Books of beauty began to appear and writings on esthetics exceeded the imagination of the rational drawing conclusions like : the width of the mouth indicated the breadth of the stomach; the mouth was the coarsest part of the face being the farthest form the face; abundant facial folds and dimples labeled a temperamental attitude; lip drape and lip protrusion were related to animalistic passion www.indiandentalacademy.com

ď‚Š The more significant description of the facial features were provided by Woolnorth who classified the facial profile into straight, convex and concave and the handsomest being the straight profile. The convex profile was attributed to a more youthful feature whereas the concave face determined the aged. ď‚Š though the idealistic features of the face changed over the years there was a denominator common to all the aesthetic marvels, physical beauty as well as constructed, that persisted consciously or subconsciously. www.indiandentalacademy.com

Whenever an artist determines the visually pleasing position or placement of the major parts of his work , he is consciously or perhaps, unconsciously, using the denominator.

Euclid revealed a visually pleasing geometric proportion which has been regarded as the formation of accepted beauty by many artists (and mathematicians). It is a ratio between the two dimensions of a plane figure or the two divisions of a line, such that the smaller element is to the larger as the larger is to the whole: the Golden Proportion. This proportional relationship asserts a natural balance, a dynamic symmetry.

The Golden Section is also called the Golden Ratio, Divine Proportion or the Golden Rectangle. www.indiandentalacademy.com

Golden proportion

1.618 = Phi 0.618 = phi

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Leonardo Fibonacci was born in Pisa, Italy, around 1175. He was the gratest European mathematician of the Middle Ages. He was the first to introduce the Hindu - Arabic number system into Europe.

By charting the populations of rabbits Fibonacci discovered a number series from which one can derive the Golden Section.

French mathematician Edouard Lucas named this series Fibonacci numbers and found their numerous significant applications.

Leonardo Fibonacci died in Pisa soon after 1240 ... www.indiandentalacademy.com

The Fibonacci numbers appear as leaf arrangements because the Fibonacci numbers form the best whole number approximations to the Golden Section.

Dividing each number in the Fibonacci series by the one which precedes, we will find the following series of numbers : 1/1 2/1 3/2 5/3 8/5 13/8 21/13 34/21 55/34 89/55

= = = = = = = = = =

1 2 1.5 1.666666666 1.6 1.625 1.615384615 1.619047619 1.617647059 www.indiandentalacademy.com 1.618181818

In the 16th Century, Luca Pacioli (1445-1514), geometer and friend of the great Renaissance painters, rediscovered the "golden secret".Luca Pacioli, however, was a great admirer of the Golden Section, as evidenced by the name of his treatise, Divina proportione, which actually comprises three independent works ( 1509 ). At the beginning Pacioli places the Compendium de divina proportione, the book about the Golden Section, which Pacioli dedicated to Duke Lodovico Sforza of Milan in December 1498.

The learned Franciscan Pacioli finds five attributes of God in this special proportion, the first four of which are unity and uniqueness, trinity, the impossibility of defining in terms of human ratio, and the immutability. In the fifth, functional comparison Pacioli sets the "divine proportion" www.indiandentalacademy.com

The properties of Phi  This is the only number in mathematics that when substracted from unity results its own reciprocal I.e  1- 1.618 = 1/1.618  Sqt 5 +1 / 2 = Phi  Sqt 5 – 1 / 2 = phi

 measurement of the sound waves also corresponds to the phi value in harmonic chords picked up by the ear. www.indiandentalacademy.com

The golden rectangle

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The Sacrament of the Last Supper by Salvador Dali (1904-1989) is painted inside a golden rectangle. Golden proportions were used for positioning the figures. Part of an enormous dodecahedron floats above the table.

The polyhedron consists of 12 regular pentagons and has fundamental golden connections.

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The Pentagon and the Golden Triangle

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The Golden Divider

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Human Age

Development Stage

Key Attributes

0

Gestation

Conception

1

Newborn

Birth

1

Infant

Walking, vocalizing

2

Toddler

Talking, expressing, imitating

3

Toddler

Self image and control, toilet training

5

Early child

Formal education begins

8

Mid child

Age of reason, knowing of right and wrong

13

Adolescent

Thinking, puberty, sexual maturation and drive

21

Young adult

Full physical growth, adult in society, education complete, beginning career, financial responsibility, eligible for voting

34

Mid adult

Refinement of adult skills, parenting role

55

Elder adult

Fulfillment of adult skills, serving, retirement begins with eligibility for Medicare, Social Security and AARP

89

Completion

Insight and wisdom into life

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The DNA molecule, the program for all life, is based on the Golden section. It measures 34 angstroms long by 21 angstroms wide for each full cycle of its double helix spiral.34 and 21, of course, are numbers in the Fibonacci series and their ratio, 1.6190476 closely approximates Phi, 1.6180339. www.indiandentalacademy.com

The top of the head to the chin relation (T-M) to the two cheeks forms a golden rectangle. The height of this rectangle is quite similar to the distance from the umbilicus to the public triangle (UP). The umbilicus (U) is golden from the top of the head (T) to thr toes (F). The shoulders (S) and outstretched arm (H) are golden to the total height (TF). The shoulders to the umbilicus to the top of the head also forms another golden rectangle. www.indiandentalacademy.com

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 Clinical facial assessment for diagnosis and treatment planning.  Arnett and Bergman presents analyses of 19 key facial traits as an adjunctive treatment planning tool used to produce improved facial and dental results.  The facial examination has to be done with the patient assuming the Natural Head position.  All examination has to be done in the with he mandible in centric relation

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Centric relation can be established as follows:  1. Patient in a 45° sitting position.  2. Use a warmed, double-thickness piece of pink base plate wax.  3. Guide the opening and closing to first tooth contact, nondeflected position.  4. Trim the wax bite to the buccal surfaces of the teeth.  5. Repeat step three.  6. Wash the wax bite in cold water.  7. Repeat step 3. www.indiandentalacademy.com

The relaxed lip position is obtained while the patient is in centric relation by the following method7:  1. Ask the patient to relax.  2. Stroke the lips gently.  3. Take multiple measurements on different occasions.  4. Use casual observation while the patient is unaware of being observed.

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ď‚Š The patient should be in the relaxed lip position because it demonstrates the soft tissue, relative to hard tissue, without muscular compensation for dentoskeletal abnormalities. Vertical disharmony between lip lengths and skeletal height (vertical maxillary excess, vertical maxillary deficiency, mandibular protrusion, mandibular retrusion with deep bite) can not be assessed without the relaxed lip posture. Existing positions and needed changes in upper incisor exposure, interlabial gap, lip length, and proportion are lost in the closed lip position. www.indiandentalacademy.com

ď‚Š Closed lip position may be adequate for normoskeletal cases but is totally inadequate for skeletal disharmony assessment (Figs. 4 and 5).

When the lips contact (distortion), the bite should be opened (Fig. 4, B) by placing a wax bite between the teeth until the lips separate in the repose posture. By using this open bite posturing, lip length and position distortion is avoided. Soft tissue cosmetic problems can then be assessed relative to needed bite changes

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Outline form and symmetry

Facial height: Hairline (H) to soft tissue menton (Me').

Facial widths: Zygomatic arch (ZA) to zygomatic arch (ZA), Gonion (G贸) to gonion (Go').

The widest dimension of the face is the zygomatic width (Fig. 1). The bigonial width is approximately 30% less than the bizygomatic dimension.

Farkas has established normal values for height and width.

The height to width proportion is 1.3:1 for females and 1.35:1 for males.

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Facial level Pupil plane (PP) is horizontal line drawn through pupils. This line is usually parallel to the horizon and is referred to as frontal postural horizontal. Upper dental arch (UDA) level is a line formed through the left and right maxillary canine tips. Lower dental arch (LDA) level is a line formed through the left and right mandibular canine tips. Chin-jaw line (CJL) is assessed by a line drawn on the under surface of the chin at maximum tissue contact. All four lines should be parallel to each www.indiandentalacademy.com other.

Constructed horizontal reference line is formed by drawing line through pupil area parallel to floor. This line is used when the pupil plane is not parallel to the floor (eyes are not level) when the head is in frontal postural horizontal.

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When pupils are not level, constructed horizontal reference line is used. A perpendicular to the constructed horizontal line through filtrum is used to assess other midline structures.

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Facial 1/3rd evaluation Face is divided into thirds by drawing lines through hairline (H), midbrow (Mb), subnasale (Sn), and soft tissue menton (Me').

The equality of the middle and the lower thirds should not be used as the determining factor in facial height changes. The appearance of the landmarks (incisor exposure, interlabial gap) within the lower third are more important in assessing balance than are the equality of the middle and the lower thirds. www.indiandentalacademy.com

With lips relaxed, lower third is subdivided by drawing lines through subnasale (Sn), upper lip inferior (ULI), lower lip superior (LLS), and soft tissue menton (Me'). The upper lip is half the length of the lower.

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ď‚Š The lips are measured independently in a relaxed position The normal length from subnasale to upper lip inferior is 19 to 22 mm.1 If the upper lip is anatomically short ( 18 mm or less), an increased interlabial gap and incisor exposure is seen with a normal lower face height. This should not be confused with vertical maxillary excess (increased interlabial gap, increased upper incisor exposure, increased lower one-third facial height).

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 The lower lip is measured from lower lip superior to soft tissue menton and normally measures in a range of 38 to 44 mm. Anatomic short lower lip is sometimes associated with Class II malocclusion and is verified by cephalometric measurement of the lower anterior dental height (lower incisor tip to hard tissue menton; women, 40 mm ± 2 mm, and men, 44 mm ± 2 mm). Anatomic short lower lip should not be confused with a short lower lip secondary to posture (upper incisor interferences) seen in Class II deep bite cases with normal anterior dental height. Anatomic short lower lip can be lengthened with a lengthening genioplasty. www.indiandentalacademy.com

Anatomic long lower lip can be associated with Class III malocclusions. This should be verified with the cephalometric anterior dental height measurement. A closed lip position will produce a long lower lip in combination with increased lower facial height (vertical maxillary excess and Class III) as the lip elongates to close. The closed lip length is misleading and should not be used for treatment planning. The normal ratio of upper to lower lip is 1:2.

Proportionate lips harmonize regardless of length; disproportionate lips may need length modification to appear in balance. Lip measurements identify normal or abnormal soft tissue length that can be related to dentoskeletal length normalcy, excess, or deficiency. www.indiandentalacademy.com

Incisor exposure is measured with lips relaxed from upper lip inferior (ULI) to maxillary incisor edge (MxlE). The upper tooth to lip (UTTL) is the vertical dimension of the incisor exposed between ULI and MxlE. Range between 1 to 1.5mm

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Interlabial gap is measured in relaxed lip position from upper lip inferior (ULI) to lower lip superior (LLS).

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Profile angle is measured by connecting points glabella (G'), subnasale (Sn), and soft tissue pogonion (Pg'). The angle is measured on the left hand side with the patient facing right.

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Fig. 11. Nasolabial angle is developed by connecting columella line (inferior nasal septum) (C), subnasale (Sn), and upper lip anterior point (ULA).

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Maxillary sulcus contour (MxSC) is subjectively assessed.

The contour is described as either accentuated, gentle curve (normal) or flat. Measurement of this contour is impractical.

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Mandibular sulcus contour (MdSC) is subjectively assessed. The contour is either accentuated, gentle curve (normal) or flat.

Measurement of this contour is impractical.

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Orbital rim projection is measured from the anterior most globe (Gb) to the orbital rim point (OR). A subjective orbital rim description is also given: Normal, flat, or protruded.

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Cheekbone contour is anteriorly facing, curved line that starts just anterior to ear, extending forward through cheekbone point (CP), then extending anterior-inferiorly ending at maxilla point (MxP) adjacent to alar base of nose. For descriptive purposes the cheekbone contour is divided into three areas: (1) zygomatic arch, (2) middle contour area, and (3) subpupil areas. These three areas, when taken together, constitute the cheekbone contour.

Reconstruction of cheekbone contour, when deficient, should analyze all three parts separately in terms of correction. CP and MxP indicates osseous cheekbone and maxillary base positions, respectively. The nasal baselip contour (Nb-LC) extends inferiorly from the maxilla point (MxP) as a gentle, anteriorly facing curve, ending just below and lateral to the mouth commissure. In normoskeletal patients the cheekbone-nasal base-lip contour complex is a smooth continuation, anteriorly facing, curved line. This line, when viewed frontally or from the side, is a definite flowing curve with no interruptions which are apparent with skeletal deformities. www.indiandentalacademy.com

Maxillary retrusion: Cheekbone-nasal base-lip curve is interrupted at MxP.

Mandibular protrusion: Cheekbonenasal base-lip curve is interrupted in upper lip area.

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Nasal projection (NP) is measured from subnasale (Sn) to nasal tip (NT). The lines through Sn and NT are perpendicular to the floor when the head is in a natural postural position.

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Throat length (TL) is assessed from neck-throat point (NTP) to soft tissue menton (Me'). This distance is subjectively described as either normal, long or short length, and with or without sag.

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Sn-Pg' line is frequently used to surgically assess chin-lip-nasal base balance.

With the VTO occlusion in Class I, the line is oriented from Sn through ideal lip position. If Pg' falls on the chin, balance of chin-lipnasal base is ideal. If Pg' falls behind the line, a chin advancement is necessary to obtain balance.

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Subnasale-pogonion reference line is generated through points subnasale (Sn) and soft tissue pogonion (Pg'). Lip projections are evaluated relative to this line.

A, Normal lip relationship to Sn-Pg' line. B, Premature aging associated with premolar extractions and incisor retraction. The lips fall on or behind the Sn-Pg' line giving the "dished-in" orthodontic appearance. The nasolabial angle may also open to unacceptable ranges.

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Sn-Pg' line is frequently used to surgically assess chin-lip-nasal base balance.

With the VTO occlusion in Class I, the line is oriented from Sn through ideal lip position. If Pg' falls on the chin, balance of chin-lipnasal base is ideal. If Pg' falls behind the line, a chin advancement is necessary to obtain balance.

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The relationship of the lips to this line is affected by the following factors: 1. Skeletal relationship: When anterior or posterior skeletal disharmony exists, producing overjet abnormalities (positive or negative), the Sn-Pg' has no validity.

2. Incisor inclinations: With a Class I skeletal pattern, the upper and lower incisors must be at proper overjet and axial inclination to produce proper protrusion of the lips relative to the Sn-Pg' line.

3. Lip thickness: The lip relationship to the Sn-Pg' line is dependent on lip thickness. The Burstone relationship is true only if the lips are the same thickness, all other factors being ideal. Class I incisors (upper incisor in front of lower incisor) produce Class I lips (upper lip in front of lower lip) only if the www.indiandentalacademy.com lips are of equal thickness.

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Systematic nasal evaluation: 1. Alar base width 2. Columella 3. Nasal tip 4. Nasal dorsum

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1. Leptorrhine: long and narrow noses 2. Mesorrhine: usually found among Asians, lack of dorsal height and columellar support 3. Platyrrhine: found in blacks and characterized www.indiandentalacademy.com by a flat, broad nose and wide nostrils.

 Radix (radix nasii):  Its is discrete but important part of nasal esthetics and preferably lie at the frontosubnasal line.  Lack of the radix will make the nose appear to have a dorsal hump.

 The nasal tip:  The most anterior point of the nose and just cephalic to the tip lies the supra tip  The supra tip break is cephalic to this and formed where the lobule meets the doral portion. Forms a slight depression that is more pronounced in the female.  Double break refers to the angular formation of the nasal tip created by the discreet definition of the tip cartilages created by supratip, tip and infratip www.indiandentalacademy.com

ď‚Š Columella is the portion of the nose between the nasal tip and the base of the nose . ď‚Š It consists of two medial crus, with intervening alveolar or fibrous tissue with covering skin.

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ď‚Š The alar base width should be the intercanthal distance. ď‚Š In females there is little fluctuation in the width after the age of 14but in males a spurt is seen from 11 to 13.

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Nasal tip: 1. Nares should be barely visible in NHP. 2. Gull in flight contour to the base of the nose.

3. The columella is slightly lower and parallel to the laa when viewed in any direction.

4. The contour of the alar cartilages should be well defined to form a scroll

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The SMILE  Philtrum height: measured in millimeters and its relation with the upper incisors and the commissure of the mouth. Commissure height is measured from the alar bases to the commissure and is normally 2 – 3mm shorter than the philtrum height Maxillary lip to upper incisor at rest www.indiandentalacademy.com

Vig and Brundel (1978): In general males show less upper incisor and more lower incisor at rest while female sshow more upper incisor and less lower incisor at rest. Whites exhibit more upper incisor show at rest than do blacks or Asians.  as age advances the upper incisor show decreases and lower incisor show increases.

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Anatomical features of excessive incisor show at rest: Short upper lip philtrum height – could be due to incomplete lip growth Vertical maxillary excess Excessive crown height Detroqued maxillary incisors www.indiandentalacademy.com

Inadequate incisor show at rest: Aging results in loss of elasticity Vertical maxillary deficiency Inadequate crown height

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 The “gummy smile” :  Is quantitated by measuring the amount of gingival display on a posed smile and full smile.  Excessive gingival display: Short philtrum Vertical maxillary excess Excessive curtain on smile. Short incisor clinical crown Upright maxillary incisors

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 Details of the lower face:  Lip projection is function of the following: Lip thickness define by age, gender and ethnicity, Dental protrusion or retrusion Maxillomandibular protrusion or retrusion.

 Labiomental sulcus is the fold of tissue between the lower lip and the chin and may vary in form and depth. Upright lower lip projection will tend to produce a shallow sulcus. And proclined incisors will deepen the sulcus.

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 Lip – chin – throat angle should be approximately 90 degrees, an obtuse angle often reflects the following:  Chin deficiency – resulting in salckiening of the submental and platysmal musculature resulting on obtuse angle.  Lower lip procumbency  Excessive submental fat  Retropositioned mandible  Low hyoid bone position. www.indiandentalacademy.com

 Cervico – mental angle: Vistnes and Souther stressed that the normal angle is 90 degrees, while other studies have suggested that it may vary from 105 to 120.  Submental or subplatysmal fat deposition,  Vertical resting hyoid bone position  Anterioposterior position of the chin  Soft tissue aging.

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 The success of orthodontic treatment is frequently related to the improvement gained in the patient’s facial appearance, particularly in relation to soft tissue. - NM Bass 2003  Experienced clinicians are generally aware of the poor aesthetic results often obtained by “treating to the numbers’ and the limitations of the cephalometric analysis. Park and Burstone (1986).  Applying statistical population means to parts of the structure of an individual face does not always produce ideal realtionships. Lundstrom (1991) www.indiandentalacademy.com

 Lundstrom and Lundstrom (1992) compared the reproducibility of the NHP and variation in the anatomic reference plane and found a variation of 4.5 to 5.6 degrees where only 2 degrees for the NHP.  Also it was shown that the NHP would produce true to life positioning of the head.  Lundstrom and Lundstrom (1995) assesed the reliability of FH plane with the NHP and NH orientation in younger children. They found a large amount of variability to make the FH plane unreliable and found that NHP adjusted to NHO formed the most reliable basis. www.indiandentalacademy.com

 The effects of ear posts, an external source of eye reference (a wall mirror), sex and time were evaluated in relation to the reproducibility of recording lateral cephalometric radiographs in this natural head posture.

Boys looked up more when changing from the selfbalance position to the mirror eye reference position (mean change 2°, P £ 0.001). No other significant maleversus-female differences were detected. NHP reproducibility was better with a mirror (with mirror, method error = 1.9°, without mirror, method error = 2.7°). No significant differences in reproducibility were detected between NHP recordings taken with and without ear posts. However, without ear posts the radiographs tended to be of poor quality. The reproducibility of sameday repeat radiographs recorded with ear posts and with a mirror (after 4 to 10 minutes and 1 to 2 hours) was 1.9°. NHP was only slightly less reproducible 3 to 6 months later (method error = 2.4°) www.indiandentalacademy.com Cooke and Wie(1988)

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Subnasale-pogonion reference line is generated through points subnasale (Sn) and soft tissue pogonion (Pg'). Lip projections are evaluated relative to this line.

A, Normal lip relationship to Sn-Pg' line. B, Premature aging associated with premolar extractions and incisor retraction. The lips fall on or behind the Sn-Pg' line giving the "dished-in" orthodontic appearance. The nasolabial angle may also open to unacceptable ranges.

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 The success of orthodontic treatment is frequently related to the improvement gained in the patient’s facial appearance, particularly in relation to sift tissue

. - NM Bass 2003

 Experienced clinicians are generally aware of the poor aesthetic results often obtained by “treating to the numbers’ and the limitations of the cephalometric analysis. Park and Burstone (1986).  Applying statistical population means to parts of the structure of an individual face does not always produce ideal realtionships.

Lundstrom (1991)

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 The success of orthodontic treatment is frequently related to the improvement gained in the patient’s facial appearance, particularly in relation to sift tissue

. - NM Bass 2003

 Experienced clinicians are generally aware of the poor aesthetic results often obtained by “treating to the numbers’ and the limitations of the cephalometric analysis. Park and Burstone (1986).  Applying statistical population means to parts of the structure of an individual face does not always produce ideal realtionships.

Lundstrom (1991)

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Subnasale-pogonion reference line is generated through points subnasale (Sn) and soft tissue pogonion (Pg'). Lip projections are evaluated relative to this line.

A, Normal lip relationship to Sn-Pg' line. B, Premature aging associated with premolar extractions and incisor retraction. The lips fall on or behind the Sn-Pg' line giving the "dished-in" orthodontic appearance. The nasolabial angle may also open to unacceptable ranges.

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