Bangalore, karnataka. Annexure II proforma for registration of subjects for dissertation



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RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,

BANGALORE, KARNATAKA.

ANNEXURE – II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION


1.


NAME OF THE CANDIDATE AND ADDRESS

(In Block Letters)

DR. S. AJIT KUMAR PILLAI.

POST GRADUATE STUDENT,

DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS,

BAPUJI DENTAL COLLEGE AND HOSPITAL, DAVANGERE – 577004,

KARNATAKA.




2.


NAME OF THE INSTITUTION

BAPUJI DENTAL COLLEGE AND HOSPITAL,

DAVANGERE.



3.


COURSE OF THE STUDY AND SUBJECT

MASTER OF DENTAL SURGERY

IN ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS.



4.


DATE OF ADMISSION TO COURSE

21st APRIL 2009




5.

TITLE OF THE TOPIC


EVALUATION OF THE INTER-INDIVIDUAL AND INTRA-INDIVIDUAL VARIATIONS OF CRANIOFACIAL REFERENCE PLANES AND THE NATURAL HEAD POSITION

-A PROSPECTIVE CEPHALOMETRIC STUDY”

6.

BRIEF RESUME OF THE INTENDED WORK


6.1: Need for the study :

Natural head position (NHP) was introduced into orthodontics in the late 1950s. Broca (1862) defined this head position as ‘when man is standing and his visual axis is horizontal, he is in the natural position’. The NHP has been found to be highly reproducible, regardless of patient’s age, gender or race, of the time lag between repeated recordings, of the radiographic or photographic technique, of the experience, or cultural background of the operator and thus a more valid craniofacial reference system.1,2


But it is not used widely, perhaps due to practical constraints such as equipment, staff training and it also requires modified cephalostats resulting in nonstandard head positioning, and difficult practical applicability.3 The photographic registration of the NHP and its transfer to tracing provides an easier and effective alternative.

This study aims to evaluate the variability, and average orientation of selected reference planes to true horizontal plane (HOR) transferred from a profile photograph taken in NHP to the cephalometric tracing, and to obtain the most reliable reference plane that can be used, where NHP cannot be attained in the lateral cephalograms.


6.2: Review of Literature :
A study was done proposing a radiographic plus photographic technique for the recording of NHP, but that study referred all longitudinal cephalograms to the first photographic NHP recording taken during the initiation of the treatment, not considering NHP modifications that can occur during treatment. A careful determination of NHP seems mandatory whenever esthetic evaluations are to be performed.4



A study was done proposing an easy way to obtain the radiographs in NHP, but it might be difficult to have flexible radiographic equipments as mentioned in the study. Moreover, the same authors also pointed out that, although the use of ear rods can modify the self balance position of the head, films taken without the ear rods are of poor quality which could destroy all the efforts performed in the recording of NHP, requiring a new exposure or a dubious interpretation.5


A study was done with the combined photographic and radiographic technique to compare three cranial base lines to a true horizontal line in NHP as reference lines for cephalometric analysis of dentofacial variation, such as Sella-nasion, Basion-nasion & Porion-orbitale, quoting that a large variability characterizes these three reference planes regarding their inclination to the true horizontal line (HOR) drawn through sella with the head in natural head position, demanding further investigation to obtain a reference plane that correlates to the true horizontal line.6
Another study was done with a similar technique which allows the evaluation of radiographs, according to both the standard intracranial references and NHP. The Frankfort plane is evaluated in NHP which showed a wide variation: 80% of the patients had orbitale lower than porion, 20% had orbitale higher than porion (mean angle 4o). The soft tissue FH plane in NHP is directed upwards in 53% of individuals. The two FH planes never coincide in all subjects.3

A study was done correlating several horizontal planes to the true horizontal plane (HOR) obtained from the photograph taken in NHP in a sample of 59 subjects, concluding that Krogman-walker line and Palatal plane offer advantages as craniofacial reference planes compared with SN or FH because of their closer orientation to HOR and similar variability, but NHP still represents a more valid craniofacial reference system than any investigated reference planes.7











7.

6.3: Objectives of the study :
  1. To compare and evaluate the inter-individual variation of the selected reference planes to the true horizontal plane (HOR).


  2. To compare and evaluate the intra-individual variation of the Natural Head Position over two months period of time.

  3. To obtain the reference planes that has the highest correlation to the true horizontal plane (HOR).


MATERIALS AND METHODS
7.1 Source of Data:
A sample of minimum 36 consecutive subjects will be selected from pre treatment patients attending the Orthodontic Department of Bapuji Dental College and Hospital, Davangere.
7.2 Method of Collection of Data :
Selection criteria

No special selection criteria is to be included, the sample will be selected with even proportions of male and female subjects which will include an equal number of growing and non growing subjects.


Method

All subjects at the initial examination (T1) will be photographically recorded in a standing mirror-guided NHP, this involves each subject performing a series of neck-bending exercises, while looking into their eyes in a wall-mounted mirror. A true vertical plumb line in front of each subject’s profile, will define the True Vertical Line (VER).


Each subject will then be instructed to keep their teeth in occlusion and lips relaxed, at which point a lateral profile photograph will be obtained with standardized photographic equipment, which is mounted on a tripod and leveled, with the optical axis of the lens horizontal and the film plane vertical.






At T2, an average of 2 months later, a second photographic NHP registration will be obtained in the same way mentioned for a minimum of 15 of these subjects to relate the intra-individual variability of the NHP.


A lateral radiograph will be obtained for each subject at T1, and traced. To produce a tracing orientated in the NHP, the true vertical plumb line will be transferred from the photograph to the tracing by electronic superimposition of the soft tissue profiles with allowance made for magnification distortion. New tracing of the T1 radiograph will then be re-orientated in the same way to the second photographic NHP registration at T2. Then the horizontal lines are traced and oriented to the true horizontal plane (HOR), constructed perpendicular to VER.
Cephalometric parameters
The selected reference planes to be investigated are


  1. HOR, True Horizontal constructed perpendicular to the true vertical line (VER)

  2. HP, Constructed Horizontal plane

  3. FH, Frankfort Horizontal

  4. SN, Sella – Nasion

  5. StN, Sella tangent – Nasion

  6. NHA, Neutral Horizontal Axis8

  7. KW line, Krogman – Walker line9

  8. P plane, Palatal plane

  9. FML, Foramen Magnum Line10

  10. AtPt, Anterior tubercle to Posterior tubercle of C1

  11. FOP, Functional Occlusal plane

  12. Md plane, Mandibular plane

  13. PM plane, Posterior Maxillary plane8

  14. PM vertical, Pterygomaxillary vertical.









8.

All angles will be defined as the minimum angular rotation from the first plane to the second, or alternatively, HOR to the reference plane. With the patient’s right profile view, a Clockwise rotation of the planes will be assigned a negative value and an Anticlockwise rotation a positive value.

The intra-individual NHP reproducibility will be determined by observing the difference in the variable HOR/SN at T1 and T2 for the minimum of 15 subjects followed up at T2.
Statistical analysis :

The significance of the inter-individual and intra-individual variations will be done using Student’s t-test and correlation between angles will be done using F test.


7.3: Does the study require any investigation or interventions to be conducted on patients or other humans or animals? If so, please describe briefly

YES


A lateral cephalogram and profile photographs has to be taken.

7.4: Has ethical clearance been obtained from your institution in case of 7.3?

YES ( recommendations enclosed )
LIST OF REFERENCES :

  1. Moorrees CF, Kean MR. Natural head position, a basic consideration in the interpretation of cephalometric radiographs. Am J Phys Anthropol 1958;16:213–23.




  1. Peng L, Cooke MS. Fifteen-year reproducibility of natural head posture: a longitudinal study. Am J Orthod Dentofac Orthop 1999;116:82–5.




  1. Ferrario VF, Sforza C, Germanò D, Dalloca LL, Miani A. Head posture and cephalometric analyses: An integrated photographic/radiographic technique. Am J Orthod Dentofac Orthop 1994;106:257-66.













  1. Frankel R. The applicability of the occipital reference planes in cephalometrics. Am J Orthod 1980;77:379–95.




  1. Cooke MS, Wei SH. A summary five-factor cephalometric analysis based on natural head posture and the true horizontal. Am J Orthod Dentofac Orthop 1988;93:213–23.




  1. Lundström F, Lundström A. Natural head position as a basis for cephalometric analysis. Am J Orthod Dentofac Orthop 1992;101:244–7.




  1. Madsen DP, Sampson WJ, Townsend GC. Craniofacial reference plane variation and natural head position. Eur J Orthod 2008;30:532–40.




  1. McCarthy RC, Lieberman DE. Posterior maxillary (PM) plane and anterior cranial architecture in primates. Anat Rec 2001;264:247–60.




  1. Rothstein T, Tarlie YC. Dental and facial skeletal characteristics and growth of males and females with Class II, division 1 malocclusion between the ages of 10 and 14 (revisited) — part I: characteristics of size, form, and position. Am J Orthod Dentofac Orthop 2000;117:320–32.




  1. Kovero O, Pynnönen S, Svahn KK, Kaitila I, Sirén WJ. Skull base abnormalities in osteogenesis imperfecta: a cephalometric evaluation of 54 patients and 108 control volunteers. J Neurosurg 2006;105:361–70.


































































































9.



Signature of the Candidate





10.


Remarks of the Guide




11.

11.1 Name and Designation of Guide

(In Block Letters)



DR.K.SADASHIVA SHETTY. MDS

PROFESSOR AND HEAD,


DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS,

BAPUJI DENTAL COLLEGE & HOSPITAL,

DAVANGERE-577 004.








    1. Signature










    1. Co-Guide (if any)








    1. Signature









    1. Head of the Department



DR.K.SADASHIVA SHETTY. MDS

PROFESSOR AND HEAD,

DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS,

BAPUJI DENTAL COLLEGE AND HOSPITAL,



DAVANGERE-577 004




    1. Signature







12.
12.1 Remarks of the Chairman & Principal









12. 2 Signature







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