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

www.indiande...




Natural head position is a standardized and
reproducible orientation of the head in space when
one is focusing on a ...






Frankfort horizontal is a useful compromise for studying
skulls but not for orienting natural head position in th...
The deviation of the Frankfort horizontal level is ,
+9degrees,middle 0 degree ,right -7 degree

www.indiandentalacademy.c...




Bjork’s studies of facial prognathism also illustrate
the unreliability of intracranial reference lines in
cephalogr...
•These findings illustrate that when SN is markedly
inclined downward, facial angles, such as SNA and
SNPg, become small a...
Two bantu subjects have low and high
inclination of sella turcica-nasion line
respectively rather than differeces in
progn...
•In a 17 year old girl studied by krog man and sassouni in
their exhaustive survey of roentgenographic cephalometry,
the F...
A women with a class 2
div 1 malocclusion
suggested a protrusive
maxilla with normal
mandible based on the
FH plane as a r...
•A study by Mc Namara shows marked difference in
maxillary development of patients with class II, division I
type malocclu...
ORIENTATION IN NATURAL HEAD
POSITION






The simplest procedure to obtain facial photographs
and head radiographs in ...
A boy assuming natural
head position by
looking into the image
of his eyes in a small
mirror located at the
same level as ...
A ten year old girl in natural head position , head tipped
slightly up and down.

www.indiandentalacademy.com
The precise location of this horizontal is immaterial,
but it may be drawn through the lowest point of the
orbital floor t...
• The Bjork polygon is oriented a nasion, and the

nasion-sella turcica line at 10 degrees from the
horizontal or at 80 de...
•A low inclination of the anterior skull base increases
the angles between SN and palatal plane, SN-occlusal
plane and SN-...
•The procedure for obtaining natural head position in
cephalometric radiography is particularly pertinent to
obtain a reli...
Facial symmetry of
eyes ears contour
of lips and
mandible

Assymetry of
eyebrows and
lips

www.indiandentalacademy.com

Ma...
•The conventional use of two ear rods to stabilize the
hed in radiographic cephalometry is based on the
assumption that th...
•Thereby, the attempt to determine facial asymmetry
of a patient generally results in a compromise rather
than as an exact...
NATURAL HEAD POSTURE




In addition to determining natural head position, as
a fixed or standardized orientation of the...
•Although, the head changes its posture continuously
throughout functional activities, Solow and Tallgren
selected the “or...
•Instrumentation has also been developed by Murphy
et al as well as Huggare for dynamic measurement of
changing head postu...
METHODS OF MEASUREMENT






A number of methods of measuring and recording head
posture, each with its advantages and ...
•Repeated measurements could record variations in
head posture over a few hours.
•A true vertical, provided by a radio opa...
•Measurements were made on these radiographs
with reference to the true horizontal.
•Electromyographic techniques have als...
•In terms of this definition, head posture is not static
and, ideally, its study requires a method that makes
it possible ...
•They found the technique to be unreliable and the
images produced not completely suitable for
detailed frame-by-frame ana...
INSTRUMENTATION






An inclinometer consisting of a contactless precision
potentiometer measuring single axis inclina...
•The inclinometer was attached to one arm of a pair
of spectacles in a position as close to the ear as
comfort would allow...
Array of instruments
assembled for recording
head posture

A subject wearing the spectacle
array

www.indiandentalacademy....
The Rustrak Ranger
adaptive data logger may
readily be carried in a
pocket

www.indiandentalacademy.com
•Downloaded to a computer, the data reflected the
postural positions of the head in the sagittal plane,
within the range o...
•Lundstrom and Lundstrom concluded that this
constructed line provided a better and more stable
reference base line for ce...
A STUDY OF STATIC AND CONTINUOUS
HEAD POSTURE





MATERIAL AND METHODS:
The sample consisted of a volunteer group of 3...
•The inclinometer was first used to record
measurements of the mean static natural head
position for each of the students ...
•Once a subject was comfortable with what was
expected of him, a 5 minute recording session of
head posture commenced.
•Ca...
Mean static vs mean walking
head posture

Mean= - 2.01 deg
S.D= 3.12 deg
Range= - 7.70 to 4.13 deg

www.indiandentalacadem...
5 measurement of NHP a
static position identified on
the continuous recording by
the five vertical dotted lines

www.india...
NATURAL HEAD POSITION vs NATURAL
HEAD POSTURE




Statistically significant differences found between
the means of the m...
•Moorrees followed the concept of Cooke and Wel
in describing natural head position as “a
standardized and reproducible po...
•Yet, great reliance is still placed on diagnosis and
treatment planning based on analyses of
cephalometric radiographs th...
•Here it may be argued that natural head posture is that
attitude of the head and face in which the patient
predominantly ...
A patient wearing the
recording apparatus and
positioned in the cephalostat

www.indiandentalacademy.com
•Various researchers have continued to examine
factors that may affect head posture.
•All of these studies have been based...
REFERENCES




Solow B. Siersboeck-Nielsen S. Cervical and
craniocervical posture as predicators of craniofacial
growth....
• Huggare JAV. A natural head position technique for
radiographic cephalometry. Dentomaxillofac Radiol
1993;22:74-76
• Moo...
•Lundstrom F, Lundstrom A. Natural head position
as a basis for cephalometric analysis. Am J Orthod
Dentofac Orthop 1992;1...
•Moorrees CF. Natural head position-a revival. Guest
editorial. Am J Orthod Dentofac Orthop
1994;105:512-513.

www.indiand...
www.indiandentalacademy.com
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Natural head posture /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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  • Indian dental academy ve been very helpul to me from both the exam point of view and also clinical point of view.......most of the things i ve learned through ur ppts...by now its a universal fact that non of the college especially mine never taught us anythin theoritical wise so this is very much the need of the hour.....pls pardon my english.
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Transcript of "Natural head posture /certified fixed orthodontic courses by Indian dental academy "

  1. 1. NATURAL HEAD POSTURE INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2.   Natural head position is a standardized and reproducible orientation of the head in space when one is focusing on a distant point at eye level. after considerable deliberation of the German anthropological society, support was solicited and reached in 1884 for the so called Frankfort agreement i.e the plane through the right and left porion and left orbitale to achieve uniformity in craniometric reasearch. www.indiandentalacademy.com
  3. 3.    Frankfort horizontal is a useful compromise for studying skulls but not for orienting natural head position in the living because the frankfort plane located in the living is normally distributed around a true extracranial horizontal. Timely warning of Downs was completely disregarded. It was he who had shown in his now classic analysis that discrepancies between cephalometric facial typing and photographic facial typing disappear. When the frankfort plane is not horizontal, but tilted up or down. www.indiandentalacademy.com
  4. 4. The deviation of the Frankfort horizontal level is , +9degrees,middle 0 degree ,right -7 degree www.indiandentalacademy.com
  5. 5.   Bjork’s studies of facial prognathism also illustrate the unreliability of intracranial reference lines in cephalograms . Two adult Bantu men were selected to represent maximum and minimum facial prognathism relative to the line nasion –sella turcica [SN]. These two individuals have almost identical profiles when shown in natural head position and illustrate the greatest variation in the inclination of the cranial base rather than the greatest differences in prognathism. www.indiandentalacademy.com
  6. 6. •These findings illustrate that when SN is markedly inclined downward, facial angles, such as SNA and SNPg, become small and facial angles are increased when SN is inclined upward. •Therefore, prognathous individuals with a low cranial base will be grouped in the orthognathous category and orthognathous individuals with high cranial base in the prognathous category. • When various methods of cephalometric analysis are applied to the study of the same cephalogram results may differ dramatically depending on the choice of reference lines. • www.indiandentalacademy.com
  7. 7. Two bantu subjects have low and high inclination of sella turcica-nasion line respectively rather than differeces in prognathism www.indiandentalacademy.com
  8. 8. •In a 17 year old girl studied by krog man and sassouni in their exhaustive survey of roentgenographic cephalometry, the Frankfort horizontal coincided with the physiologic or true horizontal. •Hence, the analyses based on the Frankfort horizontal correctly described this patient as having a maxillary protrusion and normal mandible because the cranial base was deflected downward in its dorsal part. • Analysis using nasion-sella turcica as a reference line arrived at an opposite and incorrect conclusion, namely a normal maxilla and a retrusive mandible. • www.indiandentalacademy.com
  9. 9. A women with a class 2 div 1 malocclusion suggested a protrusive maxilla with normal mandible based on the FH plane as a reference line and conversely a normal maxilla but retrusive mandible with sella nasion reference line. www.indiandentalacademy.com
  10. 10. •A study by Mc Namara shows marked difference in maxillary development of patients with class II, division I type malocclusion covers maxillary prognathism to maxillary retrognathism. The distribution actually represents variations not only in maxillary prognathism but also in the inclination of the anterior skull base. •The left side of the distribution represents individuals with a low skull base inclination that reduces the SNA angle for orthognathious maxilla to a retrognathious status. www.indiandentalacademy.com
  11. 11. ORIENTATION IN NATURAL HEAD POSITION    The simplest procedure to obtain facial photographs and head radiographs in natural head position is to instruct patients to sit upright and look straight ahead to a point at eye level on the wall in front of them. For professional photographers, natural head position is routinely used for facial photographs. For the Downs and Tweed analyses, based on the Frankfort horizontal, a perpendicular line is drawn to the edge of the film, which is taken to represent an extracranial or true horizontal. www.indiandentalacademy.com
  12. 12. A boy assuming natural head position by looking into the image of his eyes in a small mirror located at the same level as the pupils of his eyes www.indiandentalacademy.com
  13. 13. A ten year old girl in natural head position , head tipped slightly up and down. www.indiandentalacademy.com
  14. 14. The precise location of this horizontal is immaterial, but it may be drawn through the lowest point of the orbital floor that can be fairly clearly ascertained to the radiograph.  Thereby, the correspondence between the extracranial horizontal and the Frankfort horizontal can be tested. A difference illustrates the effect and extent of discrepancy between the findings when the Frankfort horizontal is used for the Downs and Tweed analyses.  when using the mesh diagram, the Bjork, or Steiner analyses, the vertical and a horizontal are drawn through nasion parallel to the edge of the film.  www.indiandentalacademy.com
  15. 15. • The Bjork polygon is oriented a nasion, and the nasion-sella turcica line at 10 degrees from the horizontal or at 80 degrees from the vertical. •For the Steiner analysis, any difference from the average (10 degrees) cant of the anterior skull base (NS) to the horizontal is used as a correction factor, because a high inclination of the anterior skull base in the individual studied enlarges the SNA, SNB, and SNPg angles, while a low inclination reduces these angles, suggesting greater or lesser amounts of maxillary or mandibular prognathism than are actually present. www.indiandentalacademy.com
  16. 16. •A low inclination of the anterior skull base increases the angles between SN and palatal plane, SN-occlusal plane and SN-occlusal plane and SN-mandibular plane, while a high inclination of the anterior skull base reduces these angles. •It is easiest to draw a line through nasion at an 80degree inclination from the vertical for all measurements and to disregard the SN-line on the tracing. www.indiandentalacademy.com
  17. 17. •The procedure for obtaining natural head position in cephalometric radiography is particularly pertinent to obtain a reliable image of the head in the so-called PA or frontal radiographic projection. These records register facial asymmetry, the extent of which can be of critical importance for treatment planning and prognosis. •The study of asymmetry is confounded by the difficulty of defining the midline of the patient’s face accurately because the midline serves as the origin for measurements. www.indiandentalacademy.com
  18. 18. Facial symmetry of eyes ears contour of lips and mandible Assymetry of eyebrows and lips www.indiandentalacademy.com Marked asymmetry of eyes ,eyebrows and ears but symmetry of lips
  19. 19. •The conventional use of two ear rods to stabilize the hed in radiographic cephalometry is based on the assumption that the transmeatal axis of humans is perpendicular to the midsagittal plane. • Actually, asymmetry is a general characteristic and the relationship of the left and right ears in their vertical and horizontal relation to each other is frequently asymmetric. • in these instances, the insertion of ear rods will obviously result in vertical and / or the horizontal rotation of the head, which introduces a deficient and misleading image. www.indiandentalacademy.com
  20. 20. •Thereby, the attempt to determine facial asymmetry of a patient generally results in a compromise rather than as an exact definition. •Only the left ear road should be used in radiographic cephalometry both for the lateral and particularly for the frontal projection. The right ear rod should be merely inserted against any part of the ear, or replaced by a soft small rubber cup, to prevent sideways movement of the head after the patient’s facial midline is aligned with the midline ruler of the cephalostat. www.indiandentalacademy.com
  21. 21. NATURAL HEAD POSTURE   In addition to determining natural head position, as a fixed or standardized orientation of the head for studying facial morphologic features, efforts have been made also to determine a functional or postural position of the head. This procedure was persued in a renewed effort to probe the relationship between dentofacial morphologic features and breathing, which, after a century of controversy still remains an enigma. www.indiandentalacademy.com
  22. 22. •Although, the head changes its posture continuously throughout functional activities, Solow and Tallgren selected the “ortho position” of subjects, name the momentary interim position when taking the first step forward from a standing to a moving or walking posture, which is reproducible acording to Molhave. •Showfety et al developed a fluid level device to record head posture prior to exposure of the head film. •In this way, head posture could be accurately reproduced for its roentgenographic record and for cephalometric analysis. www.indiandentalacademy.com
  23. 23. •Instrumentation has also been developed by Murphy et al as well as Huggare for dynamic measurement of changing head posture. •In any case, the terms natural head position and head posture are not interchangeable, one being a standardized procedure applied to all individuals for analysis of dentofacial morphology and the other an individually characteristic physiologic posture of the head to study the relation between posture and morphologic features. www.indiandentalacademy.com
  24. 24. METHODS OF MEASUREMENT    A number of methods of measuring and recording head posture, each with its advantages and limitations. A straight edge ruler and protractor have been used in some craniometric studies to measure natural head position relative to a true vertical reference line. The procedure described by Vig et al relates points marked on the soft tissues of the face to a gravity defined vertical. www.indiandentalacademy.com
  25. 25. •Repeated measurements could record variations in head posture over a few hours. •A true vertical, provided by a radio opaque plumb line, has also been used in radiographic cephalometric studies of head posture. •Although less accurate, photographic methods have also been useful in the study of facial features relative to extracranial reference lines. •Bjerin transferred true horizontal lines from profile photographs of subjects to their lateral skull radiographs. www.indiandentalacademy.com
  26. 26. •Measurements were made on these radiographs with reference to the true horizontal. •Electromyographic techniques have also been used in attempts to determine specific physiologic head positions, such as dorsiflexion and ventroflexion. •These studies have provided no definite standards against which head posture can be measured. •Lundstrom defined natural head posture as a small range of positions oscillating around the individual’s mean NHP. www.indiandentalacademy.com
  27. 27. •In terms of this definition, head posture is not static and, ideally, its study requires a method that makes it possible to measure and record postural changes continuously. •The observation also makes evident the need to draw a distinction between the concepts of position (static) and posture (dynamic). •Cleall el al recorded dynamic changes in head posture by means of cinefluorography, a procedure that exposed their subjects to radiation for relatively long periods. www.indiandentalacademy.com
  28. 28. •They found the technique to be unreliable and the images produced not completely suitable for detailed frame-by-frame analysis. •Murphy et al also recognized merit in developing an accurate measuring device capable of the continuous recording of head position as it may change over extended periods. •Such a measuring device would be valuable in the study of head posture during normal daily activities, and specifically, in the measurement of NHP during oral functions such as mastication and swallowing. www.indiandentalacademy.com
  29. 29. INSTRUMENTATION    An inclinometer consisting of a contactless precision potentiometer measuring single axis inclinations was selected for the accurate measurement of inclinations and declinations of the head. The first version of this instrument weighted just less than 30g and the latest version weighs less than 9g. The response time to changes in position was 0.3 seconds with a tilt sensibility, including hysteresis, of 0.01 degrees. www.indiandentalacademy.com
  30. 30. •The inclinometer was attached to one arm of a pair of spectacles in a position as close to the ear as comfort would allow. •This reduced the force moment acting on the occipital condyles. •A small switchbox containing a size AA battery provided the power source. •A Rustrak Ranger (Gulton Industries East Greenwich, Conn) adaptive data logger was used to record the flow of analog output emanating from the inclinometer. www.indiandentalacademy.com
  31. 31. Array of instruments assembled for recording head posture A subject wearing the spectacle array www.indiandentalacademy.com
  32. 32. The Rustrak Ranger adaptive data logger may readily be carried in a pocket www.indiandentalacademy.com
  33. 33. •Downloaded to a computer, the data reflected the postural positions of the head in the sagittal plane, within the range of 0 to 60 degrees relative to a gravity defined vertical. •Lundstrom and Lundstrom studied the reproducibility of NHP as well as the variability of three standard cephalometric reference lines. •The three lines varied greatly in their relationshp to sa true horizontal line drawn through the sella turcica with the head held in NHP. www.indiandentalacademy.com
  34. 34. •Lundstrom and Lundstrom concluded that this constructed line provided a better and more stable reference base line for cephalometric analysis. www.indiandentalacademy.com
  35. 35. A STUDY OF STATIC AND CONTINUOUS HEAD POSTURE    MATERIAL AND METHODS: The sample consisted of a volunteer group of 30 male dental students, 20 to 30 years old, all of whom were free of neck pathosis, chronic respiratory infections, or severe allergies, which could have influenced the outcome of the study. They were predominantly nose breathers with competent lips and no obvious postural deformities. The study was approved by the Committee for Research on Human Subjects, University of Witwatersrand, Johannesburg. www.indiandentalacademy.com
  36. 36. •The inclinometer was first used to record measurements of the mean static natural head position for each of the students in the sample, determined according to the techniques described by Molhave and by Sandham. •The continuous measurement and recording of head posture in walking subjects was conducted in a large hall with bland walls, no direct vision to the outside, and good artificial lighting. •A route of approximately 25m was provided along which the subjects could walk in an unobstructed manner. www.indiandentalacademy.com
  37. 37. •Once a subject was comfortable with what was expected of him, a 5 minute recording session of head posture commenced. •Care was taken to ensure that the experiment was repeated at about the same time and in the same manner on each of the 5 days. •A Kruskal-Wallis one-way analysis by ranks was conducted to determine whether there were significant differences (P<.05)between the head postures determined on the different days. www.indiandentalacademy.com
  38. 38. Mean static vs mean walking head posture Mean= - 2.01 deg S.D= 3.12 deg Range= - 7.70 to 4.13 deg www.indiandentalacademy.com
  39. 39. 5 measurement of NHP a static position identified on the continuous recording by the five vertical dotted lines www.indiandentalacademy.com
  40. 40. NATURAL HEAD POSITION vs NATURAL HEAD POSTURE   Statistically significant differences found between the means of the measurements of natural head position (static) and of the dynamically recorded walking head position and head posture. The distinction was emphasized by Moorrees, who identified natural head posture as being physiologic in character and determined by the orthoposition technique suggested by Molhave. www.indiandentalacademy.com
  41. 41. •Moorrees followed the concept of Cooke and Wel in describing natural head position as “a standardized and reproducible position of the head in an upright posture, the eyes focused on a point in the distance at the eye level”. •Orthodontists include in their treatment objectives the desire to match physiologic, functional, and esthetic ideals. www.indiandentalacademy.com
  42. 42. •Yet, great reliance is still placed on diagnosis and treatment planning based on analyses of cephalometric radiographs that have been taken while the patient is constrained by a cephalostat to a position that brings the Frankfort plane to a true horizontal. •An effective, convenient, and accurate means of recording natural head posture as a dynamic entity has now been developed. •Serious consideration could be given to utilizing this technology in cephalometric radiology. www.indiandentalacademy.com
  43. 43. •Here it may be argued that natural head posture is that attitude of the head and face in which the patient predominantly lives and which he or she presents to the world. •Since orthodontists are vitally concerned with physiological totality, it may even be an advantage to have the cephalometric means to monitor postural changes occurring in response to physiologic changes. www.indiandentalacademy.com
  44. 44. A patient wearing the recording apparatus and positioned in the cephalostat www.indiandentalacademy.com
  45. 45. •Various researchers have continued to examine factors that may affect head posture. •All of these studies have been based on purely static recordings of cranial posture. •If natural head posture does indeed oscillate around the individual’s mean natural head position, the question arises as to whether static recordings of head posture are appropriate. www.indiandentalacademy.com
  46. 46. REFERENCES   Solow B. Siersboeck-Nielsen S. Cervical and craniocervical posture as predicators of craniofacial growth. Am J Orthod Dentofac Orthop 1992;101 :449458. Murphy KE, Preston CB,Evans Wg. The development of instrumentation of the dynamic measurement of changing head posture. Am J Orthod Dentofac Orthoped 1991;99:520-526. www.indiandentalacademy.com
  47. 47. • Huggare JAV. A natural head position technique for radiographic cephalometry. Dentomaxillofac Radiol 1993;22:74-76 • Moorrees CFA. Natural head position-a revival. Am J Orthod dentofac Orthop 1994;105:512-513 • Viazis AD. A cephalometric analysis based on natural head position. J Clin Orthod 1991;25:172181 • Viazis AD. Atlas of Orthodontics: Principles and clinical Applications. Philadelphia: WB Saunders: 1993;74 www.indiandentalacademy.com
  48. 48. •Lundstrom F, Lundstrom A. Natural head position as a basis for cephalometric analysis. Am J Orthod Dentofac Orthop 1992;101:244-247 •Lundstrom A, Forsberg CM, Westergren H, Lundstrom FA. A comparison between estimated and registered natural head posture. Eur J Orthod 1990;13:59-64 •Murphy KE, Preston CB, Evans WG. The development of instrumentation for the dynamic measurement of changing head posture. Am J Orthod Dentofac Orthop 1991;99:520-526 www.indiandentalacademy.com
  49. 49. •Moorrees CF. Natural head position-a revival. Guest editorial. Am J Orthod Dentofac Orthop 1994;105:512-513. www.indiandentalacademy.com
  50. 50. www.indiandentalacademy.com

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