Dr. Deepesh Agrawal
Department of Orthodontics
Jaipur Dental College
Cephalometric analysis for diagnosis and treatment planning of orthodontic patients is essentially a measurement system designed to describe relationships between various parts of the skeletal, dental and soft tissue elements of the craniofacial complex. As the linear and angular measurements vary between males and females and with age, one of our objectives was to compare the statistical difference between males and females. The study was performed using a sample size of 60 cephalometric radiographs of 30 males and 30 females. The samples were selected on the basis of class I dental relationship with clinically acceptable profile, no history of orthodontic treatment and of the Jaipur (Rajasthan) population.
Keyword: Cephalometric analysis, orthodontic patient, cephalometric radiographs, orthodontic treatment, craniofacial complex, dental
The introduction of the cephalometer to orthodontics by Broadbent in1931 provided the avenue for the creation of series of cephalometric analysis.2,3 Roentgenographic cephalometry was first developed as a tool to study craniofacial growth and development.4,6,5Later the uses were expanded to include the growth prediction of individual patients, diagnosis and treatment planning and assessment of treatment progress.4,5,3
One of the most valuable adjuncts to diagnosis and treatment planning available to orthodontists is the lateral cephalogram. A well-planned cephalometric analysis is invaluable as it offers a gradually consistent and dependable guide to diagnosis and treatment planning.7However no two faces are alike, with the exception of monozygotic twins and even right and left halves of the face do not match perfectly, but show subtle differences.8 The use of any analysis as a definitive formula, without proper consideration for age, sex, type, anatomic limitations and ethnic differences, will invariably result in frustration and failure.7,6Steiner stresses that any analysis is not complete until it has been individualized and has been adjusted to needs of particular patient under consideration. According to Steiner “These estimates are useful as guides but must be modified for the individuals”.12
A number of investigators noticed the variation of craniofacial morphology in different ethnic groups.5 Richardson defined an ethnic group as a “nation or population with a common bond such as geographical boundary, a culture or language or being radically or historically related.”6,5 The standards of beauty vary from race to race, place to place and from time to time. Similarly, the morphologic feature varies from one ethnic group to another. Therefore, it is important to know the normal Dentofacial pattern of each group for better clinical evaluation.9Cephalometric norms can be invaluable aids to the practitioner in determining the location as well as severity of existing abnormalities.10,6 Norms define ideal cephalometric measurements for a patient based on factors such as age, sex, size and race. If the patient deviates from a norm by a margin greater than that prescribed by the clinician, it will influence diagnostic and treatment planning procedures.10The knowledge of cephalometric norms is important for clinical and research purposes.11
The present study was designed to establish the skeletal cephalometric norms of the Jaipur population. Jaipur is a capital city of Rajasthan, a northern state of India with diverse population group and culture. We had selected the male and female subjects of clinically acceptable class I occlusion and balanced profile, to set up norms for the population, to investigate the significant differences between them, so that the data obtained can be an aid in the cephalometric treatment planning for local population and to compare the data obtained with that of norms of Caucasians.
Materials and Methods:
Materials: In the present study lateral cephalograms of 60 adult subjects, 30 females and 30 males were included. All the cephalograms were obtained from the records of the department of Orthodontics and Dentofacial Orthopedics, Jaipur Dental College and Hospital, Jaipur. Age group of selected subjects was in the range of 18 – 25 years. The total numbers of subjects were determined based on discussion held with biostatistician. The study was reviewed by board of ethical committee of the dental college and passed.
Criteria for selection of the sample
- Class I molar and canine relationship.
- Overjet and overbite not exceeding more than 2- 4mm, with little or no incisor crowding or rotations.
- Full compliment of permanent teeth in proper occlusion, except third molars.
- No apparent skeletal or dental deformity.
- Acceptable facial profile
- No previous history of orthodontic, orthognathic or plastic surgery.
All the radiographs were obtained in natural head position with centric occlusion and lips relaxed. Cephalometric radiographs, Plaster models and extraoral and intraoral photographs of each subject were obtained with their consent.
All the cephalograms used in the study were obtained by a single operator and in a single machine. The cephalograms were taken with a standard “ROTOGRAPH 230 EUR” cephalostat, manufactured by VILLA MEDICAL SYSTEM in 1995 made in Milano, Italy. Standardized 8”x10” Kodak green sensitive lateral radiographic head films with intensifying screen were used for each subject. The distance between X- ray sources to subjects was kept at a constant distance of 5 feet and the film kept at a constant distance of 16 cm from the midsagittal plane of the subject. The radiographs were obtained with the subject in natural head position, seated condyles and lips in relaxed position. A mirror was hung on the wall facing the cephalostat at a distance of 5 feet. The subjects were asked to look directly into the reflection of their eyes. The subjects were asked to take a few steps towards the mirror looking into the reflection of their eyes. The procedure was repeated. The cephalostat brought down into position, the ear rods were lightly placed into the external auditory meatus of the subject. This ensures the stability of the transverse plane. The nasion holder of the cephalostat gently placed on the bridge of the nose to stabilize the head in the vertical plane. The vertical plane and horizontal alignment of the film cassette was checked. The subject was asked to swallow and bite into centric occlusion with lips in relaxed position. The film was exposed while operating the cephalostat at a constant of 80 KVP, 8mA and 3 seconds film exposure time. All the exposed film were developed and fixed manually by a single technician using a standard procedure.
All the cephalograms were traced by a single operator on Garware matted acetate tracing paper of 0.003”thickness and with 3 H microlead pencil. Cephalometric landmarks were located, identified and marked. The parameters used in the study were taken from, Steiner12, Downs13, Tweed14, McNamara16 and Jaraback analysis17. Overall 17 measurements including 5 linear, 11 angular and 1 proportional measurements were used. 20 cephalograms 10 out of each group (30 male and 30 female) were randomly selected and retraced 10 days after the first tracing to check intra examiner error of measurement.
Reference points used for this study. (Figure I)
- Sella – the point representing the midpoint of the pituitary fossa or sella turcica. It is a constructed point.
- Nasion – most anterior point in the mid way between the frontal and nasal bones on the frontonasal suture.
- Orbitale – lowest point on inferior bony margin of the orbit.
- Point A – deepest point in the midline between anterior nasal spine and the crest of the maxillary alveolar process.
- Point B – deepest point in the midline between the alveolar crest of the mandible and the mental process.
- Pogonion – most anterior point of the bony chin in the median plane.
- Gonion – constructed point at the junction of ramal plane and the mandibular plane.
- Menton – most inferior midline point on the mandibular symphysis.
- Gnathion – most antero – inferior point on the symphysis of the chin.
Various parameters used in the study (figure II, III and IV)
From Steiner analysis
- SNA – 820
- SNB – 800
- ANB - 2 0
- GoGn – SN – 320
- Upper incisor to NA (angle) – 220
- Upper incisor to NA (linear) – 4mm
- Lower incisor to NB (angle) – 250
- Linear incisor to NB (linear) – 5mm
- Interincisal angle – 1310
From McNamara analysis,
- Nasolabial angle
From Downs Analysis,
- Y – Axis – 59.40 +/- 3.820
From Tweed Analysis,
- IMPA – 900
From Jaraback Analysis,
- Upper incisor to SN – 1020 +/- 20
- Anterior facial height
- Posterior facial height
- Jarabak’s ratio
From Ricketts Analysis
- E – line - +/_ 2
Statistical analysis used
Mean, standard deviation was calculated. The “Z” test was used to determine whether there was a statistical difference between males and females. The p value, < 0.05 was taken to be statistically significant.
Intraexaminer reliability was also tested by “Z”test. The entire data was analyzed using SPSS (Statistical Package for Social Science, V10.5) package.
Results and observations:
Data obtained from 60 cephalometric radiographs taken from the Jaipur population were averaged. Mean, standard deviation values were calculated. The values obtained in males and females were compared statistically using ‘Z’ test. The p value < 0.05 was taken to be
statistically significant. The results are listed in tables 1 through 12. 20 randomly selected cephalometric radiographs were retraced and Pearson correlation coefficients were calculated to check the error between two tracings and the results are listed in tables 7, 8, 9.
Table 1 shows mean distribution of skeletal norms for males and females in the population respectively. The mean values of males for SNA, SNB, ANB, Y-axis, were 82.970, 81.500, 1.50 0, 63.230 respectively for males and 80.200, 79.100, 1.100, 65.230 respectively for females found to be near normal to that of Caucasian norms. But GoGnSN, Jarabak’s ratio 24.600, 70.60% for males and 27.700, 66.90% respectively for females indicates mild tendency to horizontal growth pattern.
Mean + Sd of Skeletal Parameters of male and female patients
Mean + Sd
82.97 + 3.28
|80.20 + 3.42|
81.50 + 3.24
|79.10 + 3.9|
1.50 + 1.48
|1.10 + 2.12|
Go-GN to SN degree
24.60 + 4.61
|27.70 + 4.56|
63.23 + 2.72
|65.23 + 3.77|
125.70 + 6.15
|154.30 + 178.96|
88.67 + 7.03
|80.77 + 5.12|
Jarabak’s ratio (%)
70.60 + 5.20
|66.90 + 4.03|
Table 2, shows mean distribution of dentoalveolar norms for males and females in the population respectively. U1- NA (angle),U1- NA(mm) , L1-NB(angle),L1- NB(mm), U1 –SN, IMPA, interincisal angle with the values of 28.670,
Mean + Sd of Dentoalveolar Parameters of male patients
|Mean + Sd|
|Interincisal angle||122.00 + 10.83||122.03 + 8.58|
|U1 to SN(degree)||111.27 + 7.21||108.87 + 8.13|
|U1 to NA(degree)||28.67 + 6.48||29.00 + 7.77|
|U1 – NA(mm)||7.77 + 3.49||6.57 + 3.01|
|L1 – NB(degree)||28.53 + 6.56||27.77 + 5.63|
|L1 – NB (mm)||6.10 + 2.74||5.67 + 1.83|
|IMPA||102.20 + 7.70||101.83 + 5.93|
7.77, 28.530 ,6.10mm, 111.270, 102.200, 122.000 for males respectively and 290, 6.57mm,27.770,5.67mm, 108.870, 101.830, 122.030 for females respectively showed bimaxillary protrusion.
Table 3, shows mean distribution of soft tissue norms for males and females in the population respectively. Nasolabial angle and E – line with the values of 92.630 and 0.80mm for males and 95.070 and 2.78mmn for females showed females have lower lips more protruded as compared to Caucasians.
Mean + Sd of Soft tissue Parameters of males
|Nasolabial Angle||92.63 + 11.72||95.07 + 9.28|
|E-line||0.80 + 3.42||2.78 + 2.73|
Table 4, indicates the statistical difference between males and females in skeletal parameter. Insignificant difference was found between males and females for values of SNA, SNB, ANB, GoGn
Statistical difference between male and female Skeletal Parameters
|SNA degree||82.97 + 3.28||80.20 + 3.42||> .05||NS|
|SNB degree||81.50 + 3.24||79.10 + 3.9||> .05||NS|
|ANB degree||1.50 + 1.48||1.10 + 2.12||> .05||NS|
|Go-GN to SN degree||24.60 + 4.61||27.70 + 4.56||> .05||NS|
|Y- Axis||63.23 + 2.72||65.23 + 3.77||> .05||NS|
|AFH (mm)||125.70 + 6.15||154.30 + 178.96||> .05||NS|
|PFH (mm)||88.67 + 7.03||80.77 + 5.12||> .05||NS|
|Jarabak’s ratio (%)||70.60 + 5.20||66.90 + 4.03||> .05||NS|
to SN, AFH, PFH, Jarabak’s ratio.
Table 5 shows the statistical difference between males and females in dentoalveolar parameter. Insignificant difference was found between males and females for the value of U1- NA (angle),U1- NA(mm) , L1-NB(angle),L1- NB(mm), U1 –SN, IMPA and interincisal angle.
Table – 5
Statistical difference between male and female dentoalveolar parameter
|Interincisal angle||122.00 + 10.83||122.03 + 8.58||> .05||NS|
|U1 to SN(degree)||111.27 + 7.21||108.87 + 8.13||> .05||NS|
|U1 to NA(degree)||28.67 + 6.48||29.00 + 7.77||> .05||NS|
|U1 – NA(mm)||7.77 + 3.49||6.57 + 3.01||> .05||NS|
|L1 – NB(degree)||28.53 + 6.56||27.77 + 5.63||> .05||NS|
|L1 – NB (mm)||6.10 + 2.74||5.67 + 1.83||> .05||NS|
|IMPA||102.20 + 7.70||101.83 + 5.93||> .05||NS|
Table 6 shows statistical difference between males and females in soft tissue parameters. Significant difference was found between males and females for the value of E – line, 0.080 for males and 2.78 for females showing female lower lip are more protruded than males.
Statistical difference between males and females Soft tissue Parameters
|Nasolabial Angle||92.63 + 11.72||95.07 + 9.28||> .05||NS|
|E-line||0.80 + 3.42||2.78 + 2.73||< 05||Sig|
Table 7, 8 and 9 indicates intra examiner error (tracing I and tracing II) for skeletal parameter, dentoalveolar parameters, soft tissue parameters respectively. The error was found to be statistically insignificant with p value >0.05.
Mean + Sd of Skeletal Parameters (Intra examiner error)
|SNA degree||81.90 + 3.30||81.80 + 2.52||> .05||NS|
|SNB degree||80.65 + 3.58||80.30 + 3.10||> .05||NS|
|ANB degree||1.25 + 1.81||1.60 + 1.43||> .05||NS|
|Gong – SN degree||25.25 + 4.71||27.20 + 4.01||> .05||NS|
|Y- Axis||63.70 + 3.29||65.20 + 2.62||> .05||NS|
|AFH (mm)||122.55 + 7.64||124.55 + 7.16||> .05||NS|
|PFH (mm)||85.50 + 6.09||85.85 + 5.63||> .05||NS|
|Jarabak’s ratio (%)||69.89 + 4.49||69.03 + 4.32||> .05||NS|
Mean + Sd of Dentoalveolar Parameters (Intraexaminer error)
|Interincisal angle||121.6 + 11.74||120.75 + 11.79||> .05||NS|
|U1 to SN(degree)||111.65 + 9.24||111.55 + 9.15||> .05||NS|
|U1 to NA(degree)||30.15 + 8.57||30.05 + 8.02||> .05||NS|
|U1 – NA(mm)||7.1 + 3.40||7.30 + 3.48||> .05||NS|
|L1 – NB(degree)||27.75 + 5.63||27.15 + 5.55||> .05||NS|
|L1 – NB (mm)||5.45 + 2.67||5.10 + 2.53||> .05||NS|
|IMPA||101.80 + 6.90||101.05 + 7.00||> .05||NS|
Mean + Sd of Soft tissue Parameters (intra examiner error)
|Nasolabial Angle||91.75 + 11.61||91.85 + 11.32||> .05||NS|
|E-line||2.20 + 3.09||1.80 + 2.84||> .05||NS|
Cephalometric analysis for diagnosis and treatment planning of orthodontic patients is essentially a measurement system designed to describe relationships between various parts of the skeletal, dental and soft tissue elements of craniofacial complex. The racial, facial and skeletal characteristics of the patients play a critical role in orthodontic treatment planning. Since soft tissues, dental and skeletal structures exhibit different patterns in different races, for successful treatment planning. All the cephalometric analyses, we use today are based on the Caucasian norms. However it is possibly incorrect to make rigid application of these values since they represent an average of one population.
The first attempt to apply cephalometric analysis to ethnic groups other than those of European ancestry was published in 1951 by Cotton, Takano and Wong20 who applied the Downs analysis to African – Americans, Japanese – American and Chinese – Americans. Since that time, various investigators have analyzed Japanese5,7,10,29,48,50 Africans26,27,30,37,Chinese 31,32,33,41,47 Indian 1,4,9,24 and other ethnic groups shown that the normal measurements of skeletal and/or dental patterns of a single group cannot be considered normal for other racial groups. Thus, different racial groups will have to be treated according to their own individual characteristics.
Indian is a subcontinent with a large number of racial subgroups and several religious and interracial mixtures. Research work in this field has been carried out by Nanda4, Valiathan9 Anuradha18, Chopra R1 and many others.
The objectives of the study were to establish cephalometric norms for the Jaipur population and to evaluate the difference between males and females. As the linear and angular measurements vary between males and females and with the age, one of our objectives was to compare the statistical difference between males and females. The study was performed using sample size of 60 cephalometric radiographs of 30 males and 30 females. The samples were selected on the basis of class I dental relationship with clinically acceptable profile, no history of orthodontic treatment and of Jaipur population.
The findings of the study was discussed under two headings, the skeletal pattern and the dentoalveolar pattern. In each category the findings were discussed and males and females were compared.
The skeletal pattern
The mean values of SNA 82.97 0 ± 3.280 and SNB – 81.500 ± 3.240 for males and SNA 80.20 0 ± 3.420 and SNB – 79.100 ± 3.90 for females was found nearer to that of Caucasians, indicating normally related maxilla and mandible to the cranial base. The mean value of ANB 1.500 ± 1.48 for males and ANB 1.100 ± 2.12 for females also matched to that of Caucasian norms indicating normally related maxilla and mandible.
Studies carried out by Valiathan9 and Nanda4 on Indian population, showed normally related maxilla and mandible to cranial base and the jaws were normally related to each other. Our findings were well-matched with these studies.
When considering the sexual dimorphism, all the male and female subjects showed statistically insignificant difference (p >0.05). The female subjects showed a relatively mild recessive mandible with the SNB angle (79.100 ± 3.90) when compared to males. Our findings were consistent with that of Nanda study, who concluded posterior positioning of mandible in relation to cranium in Lucknow population. However, the males in our study showed anterior position of mandible relative to cranial base than females. This was supported by mild increase in SNB value(81.500±3.240).
GoGnSN (24.600 ± 4.610), Y-axis (63.230 ± 2.720), Jarabak’s ratio (70.60 ± 5.20 %) for males and GoGnSN (27.700 ± 4.560), Y-axis (65.230 ± 3.770), Jarabak’s ratio (66.90 ± 4.03 %) showed mild tendency to horizontal growth in Jaipur population. The values obtained from our study was matching with study conducted on other Indian population.1,4,18 ,Valiathan9 and others , showed Jarabak’s ratio established for south Indian males and females and north Indian males and females demonstrated a more horizontal growth pattern. In our study when males and females were compared all these values except Jarabak’s ratio were almost similar with no statistically more in males than females.
Anterior facial height and posterior facial height showed insignificant (p value >0.05) difference between males and females, in which males showed AFH value of 125.70mm, females 154.30mm. PFH in males 88.67mm and in females 80.77mm. Our study values corresponds with Valiathan and others9 , who established the AFH to be 124.74mm for males and 116.54mm for females while PFH for males and females to be 88.60mm and 78.74mm respectively.
According to Nanda4 the skeletal patterns of the Lucknow population was almost similar with that of American whites but was retrusive compared to Chinese while Negroes, had little facial protrusion and slight retrusion of the lower face and the Japanese showed mean values nearer to mean values of North Indians and Caucasians.
The dentoalveolar pattern
The mean values of dental pattern of the present study showed wide difference with the mean values offered for Caucasians norms. The dentoalveolar parameters showed an increase in the mean values. This increase in dental pattern was supported by both linear and angular measurements.
The inclination of upper anterior were relatively forward than the Caucasian norms which was indicated by U1 – NA 28.670 and 7.77 mm, U1 – SN 111.270 for males and U1 – NA 29.000 and 6.57 mm, U1 – SN 108.870 for females, indicates upper anterior protrusion. A distinct increase in L1 – NB 28.530 and 6.10 mm, IMPA 102.200 for males and L1 – NB 27.770 and 5.67 mm, IMPA 101.830 for females indicates proclination of lower anteriors when compared to Caucasians. The study results agree with Chopra and others1 study, where the IMPA values were higher in Indore cosmopolitan group. Our results were almost similar with that of the results obtained in other studies on Indian population.1, 4,9,19 where the authors concluded bimaxillary protrusion in their samples.
However, surprisingly, with the high degree of protrusive mean value of dental pattern, all the subjects in the exhibited pleasing appearance and good facial harmony. According to Nanda4, in treating any Indian population a slight protrusion of teeth in comparison with Caucasian standards will be optimum for their features.
Statistically insignificant (p>0.05) difference was seen in the males and female samples. Although both the groups showed proclination of upper anterior teeth, males showed slightly more values in U1 – NA and U1 – SN, L1 – NB and IMPA than females.
There seems to be dentoalveolar compensation in both male and female skeletal patterns. As the males in the present study showed mild mandibular prognathism, maxillary incisors were proclined in order to maintain ideal overjet and to relate the dentition normally to each other thus not exaggerating the skeletal prognathism.
The interincisal angle was also smaller in our study group indicating labial positioning of both the upper and lower teeth. In males and females U1 – L1 showed statistically insignificant difference with the greater values in males.
The soft tissue pattern
The mean values of soft tissue pattern in the present study were found nearer to that of Caucasians. Considering the sexual dimorphism, all the male and female subjects showed statistically insignificant difference (p >0.05) for Nasolabial angle (92.63± 11.72 for males and 95.07± 9.28 for females). The E – line values for males (0.80±3.42) found statistically significant with values of females (2.78±2.73). It indicates that females have a more protrusive lower lip than males.
According to Nanda4 north Indian population had significantly more protrusive teeth than Caucasians but lesser than Negroes and Chinese who had more protrusive upper and lower teeth and Japanese group was nearly same as north Indians. The results obtained from our study were consistent with other studies on Indian populations. It demonstrated the fact that norms and standards of one population could not be used without modification for another group. The basic criterion for inclusion of samples in our study was a clinically acceptable permanent occlusion and good profile, it should be kept in mind that wide range of variations and different combinations could be present even in individuals with ideal Dentofacial features. Future research should rather pursue a longitudinal approach to refine our understanding.
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