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| Year : 2012 | Volume
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| Issue : 4 | Page : 447-453 |
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| Digital radiograph of the middle phalanx of the third finger (MP3) region as a tool for skeletal maturity assessment |
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Deepa Y Hegde1, Sudhindra Baliga2, Ramakrishna Yeluri1, AK Munshi1
1 Department of Pedodontics and Preventive Dentistry, K.D. Dental College and Hospital, Mathura, Uttar Pradesh, India
2 Department of Pedodontics and Preventive Dentistry, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India
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| Date of Web Publication | 20-Dec-2012 |
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 Abstract | | |
Objective: To evaluate the reliability of the digital radiograph of the middle phalanx of the third finger (MP3) in skeletal maturity assessment
Study Design: Fifty children (24 girls and 26 boys) belonging to the circumpubertal age-group were selected for the study. Two radiographs - lateral cephalogram and digital radiograph of the MP3 region - were taken in each child. Age assessment was based on the changes in shape of the cervical vertebrae and the epiphysis of the middle phalanx of the third finger of the left hand. The radiographs were assessed by three examiners. The inter- and intraexaminer variability were determined by the Wilcoxon rank sign test and the Kruskal-Wallis test and were found to be nonsignificant. Examiner 3 showed the best intraexaminer agreement and was selected to evaluate the radiographs for the entire study.
Results: The correlation determined between the MP3 stages and cervical vertebrae maturity index (CVMI) stages, the peak-wise distribution of the MP3 stages, and the correlation between the MP3 stages and the chronological age were found to be highly significant.
Conclusions: Digital radiograph of the MP3 region is definitely a simple, reliable, cost-effective, and time-saving technique for the assessment of skeletal maturity. Keywords: CVMI, digital radiograph, MP3, skeletal maturity
How to cite this article:
Hegde DY, Baliga S, Yeluri R, Munshi A K. Digital radiograph of the middle phalanx of the third finger (MP3) region as a tool for skeletal maturity assessment. Indian J Dent Res 2012;23:447-53 |
How to cite this URL:
Hegde DY, Baliga S, Yeluri R, Munshi A K. Digital radiograph of the middle phalanx of the third finger (MP3) region as a tool for skeletal maturity assessment. Indian J Dent Res [serial online] 2012 [cited 2023 Jun 6];23:447-53. Available from: https://www.ijdr.in/text.asp?2012/23/4/447/104947 |
The developmental status of a child is usually assessed in relation to the physical events that take place during the progress of growth, such as the skeletal ossification stages, the attainment of the peak growth velocity, or the pubescent changes in the body. Although growth events occur in a reasonably constant sequence, the ages at which they are reached vary considerably among children. The indicators of the developmental age are, therefore, more informative than the chronological age, particularly for clinical application. [1]
The current concept of orthognathic procedures has served to increase not only our technical mastery over the oral cavity but also our control over the physiognomy of the face. We happen to be fortunate that, by mere coincidence, our treatment frequently coincides with the surge of physiologic changes that take place in our patients. Hence, more attention should be paid to growth, since we have the tools to observe and possibly predict its characteristics. [2] One important method currently used for determining whether pubertal growth has started, is occurring, or has been completed is hand-wrist radiographic evaluation. [3]
In a growing child the clinician may come across many abnormal conditions that need intervention. One of these interventions is growth modification. A series of biologic indicators have been used to assess the growth spurts in order to determine the optimal timing for growth modification. These methods have included sexual maturation characteristics, [4],[5],[6] facial growth and peak growth velocities, chronological age, [6] dental development, [7] body height, [8],[9] body weight, and hand-wrist maturity. [1],[10],[11],[12] The clinical convenience of using dental x-ray film and machine for recording the adductor sesamoid [12],[13] and middle phalanx of the third finger (MP3) stage [14] encouraged us to use the new technology of digital dental radiography. Some studies have already been reported in the literature where various aspects of skeletal maturity were correlated with growth assessment. [4],[10],[12],[15],[16]
The present study was done to assess the reliability of a simple, cost-effective, and time-saving method -digital radiography of the MP3 region - for maturity assessment and to compare it with a known standard like cervical vertebrae maturity assessment (CVMA); we also wanted to categorize the MP3 findings into clinically relevant categories like prepeak, peak, and postpeak stages.
| Materials and Methods | |  |
Fifty children (24 girls and 26 boys) between 8 and 18 years of age were included in this study. The subjects were selected randomly from among the patients who visited the hospital. To ensure that the subjects were within or close to the circumpubertal period, girls between 8-16 years and boys between 10-18 years were selected as subjects for this study; the difference in the age-groups selected was because of the difference between boys and girls in the age of onset of puberty. Ethical committee clearance was obtained prior to the commencement of the study, and written consent was obtained from the parents/guardian prior to the radiographic exposures.
All the children were subjected to:
- Lateral cephalograms
- Digital radiographs of the MP3 region
The lateral cephalograms were taken using an extraoral radiograph machine (Rotograph Plus, Villa Sistemi Medicali, Buccinasco, Italy) and x-ray film (Kodak TMX, Colorado, USA) of size 8 × 10 inches. The exposure parameters were 70 KVp, 10 mA, and 1.2 second. The source-to-midsaggital plane distance was kept at 60 inches [Figure 1].
The digital radiographs of the MP3 region were taken using the standard radiographic machine (Gnatus Equipamentos Médicos Odontológicos LTDA, Brazil) and a digital radiographic system (Dr. Suni, Digital Radiography System, Suni Medical Imaging Inc, USA); the exposure parameters were 70 KVp , 7 mA, and 0.08 seconds.
For capturing the digital radiographic image, the patient was instructed to place his/her left hand on the table, with the fingers spread apart. The finger of the concerned subject ie, the third finger,was kept straight along the long axis of the intra oral dental charged couple device (CCD) sensor (size #2),with the MP3 region placed in the center of the CCD sensor.The cone of the radiographic machine was positioned perpendicular to the area of interest and in light contact with the middle finger of the left hand [Figure 2]. Only those radiographs and images with good clarity were included in the study. The assessment of the MP3 developmental stages was carried out according to the stages suggested by Hagg and Taranger. [3]
All the lateral cephalograms obtained were traced on matte acetate paper of 0.003-inch thickness with a 2H pencil. The method proposed by Lamparski [17] and modified by Hassel and Farman [10] was used for the assessment of the cervical vertebrae. The stages were categorized and recorded as described below.
Developmental stages of cervical vertebrae [Figure 3] and [Figure 4] [10]
CVMI 1 (Initiation) : The inferior borders of C2, C3, and C4 are flat in this stage. The vertebrae are wedge shaped, and the superior vertebral borders are tapered from posterior to anterior. About 80%-100% of adolescent growth remains to be completed.
CVMI 2 (Acceleration): Concavities develop on the inferior borders of C2 and C3. The inferior border of C4 is flat. The bodies of C3 and C4 are nearly rectangular in shape. About 65%-85% of adolescent growth remains to be completed.
CVMI 3 (Transition): Distinct concavities are seen in the inferior borders of C2 and C3. A concavity is beginning to develop in the inferior border of C4. The bodies of C3 and C4 are rectangular in shape. About 25%-65% of adolescent growth remains to be completed.
CVMI 4 (Deceleration): Distinct concavities are seen in the inferior borders of C2, C3, and C4. The vertebral bodies of C3 and C4 are becoming squarer in shape. About 10%-25% of adolescent growth remains to be completed.
CVMI 5 (Maturation): More accentuated concavities are seen in the inferior borders of C2, C3, and C4. The bodies of C3 and C4 are square or nearly square in shape. About 5%-10% of adolescent growth remains to be completed.
CVMI 6 (Completion): Deep concavities are seen in the inferior borders of C2, C3, and C4. The bodies of C3 and C4 are square or have greater vertical dimension than horizontal dimension. Little or no adolescent growth remains to be completed.
The CVMI stages were also categorized into pre-peak, peak, and post-peak stages according to the method proposed by Kucukkeles et al.[16] [Table 1].  | Table 1: Categorization of the CVMI stages into prepeak, peak, and postpeak stages
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The MP3 findings were categorized into five stages [3] as follows [Figure 5] and [Figure 6]: | Figure 5: Diagrammatic representation of the developmental stages of the MP3 region.
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- MP3-F: The epiphysis is as wide as the metaphysis; this denotes the onset of the pubertal growth spurt.
- MP3-FG: The epiphysis is as wide as the metaphysis and there is a distinct medial and/or lateral border of the epiphysis forming a line of demarcation at right angles to the distal border.
- MP3-G: The sides of the epiphysis are thickened and caps its metaphysis forming a sharp edge distally on one or both sides.
- MP3-H: Fusion of the epiphysis and metaphysis has begun. This is the deceleration period of the pubertal growth spurt.
- MP3-I: Fusion of the epiphysis and metaphysis is complete. This marks the end of the pubertal growth spurt.
The MP3 stages were also categorized into the pre-peak, peak, and post-peak stages as suggested by Madhu et al.[15] [Table 2]. | Table 2: Categorization of the maturational stages of the MP3 into prepeak, peak, and postpeak stages
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Statistical analysis
All statistical analysis were performed using SPSS® (Statistical Package for Social Sciences) for Windows®, version 12. Statistical significance was set at P=.05.
In order to assess the inter- and intraexaminer variability, prior to the study, we asked three observers (A, B, and C) to evaluate a sample of 15 MP3 images and lateral cephalograms on two occasions, 2 weeks apart.The results were statistically analyzed using Wilcoxon signed rank sum test [Table 3] and Kruskal-Wallis test [Table 4] to determine the interexaminer and intraexaminer variability, respectively. The results were not found to be significant. The least variability was found with the observations of examiner C and, hence, she evaluated all the radiographs in the study.  | Table 3: Determination of interexaminer variability using Wilcoxon signed rank test
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 | Table 4: Determination of intraexaminer variability using Kruskal-Wallis Test
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The data thus gathered was further statistically evaluated. The correlation between the percentage distribution of the subjects within the MP3 and CVMI stages and the peak-wise distribution of the MP3 stages were statistically analyzed using Pearson's chi-square test; ANOVA was used to determine the correlation between the MP3 stages and the chronological age.
| Results | | |
The percentage distribution of the subjects within the MP3 and CVMI stages is presented in [Table 5] and [Figure 7]. [Table 6] and [Figure 8] show the peak-wise distribution of the MP3 stages into prepeak, peak, and postpeak stages. The correlation of the above mentioned distributions were analyzed statistically and were found to be very highly significant [Table 7] and [Table 8]. It was observed that the prepeak stage was represented by MP3F and MP3FG in 95% of the subjects, the peak stage was represented by MP3G in 64.71% of the subjects, and the postpeak stage was represented by MP3H and MP3I in 100% of the subjects. | Table 7: Correlation between the distribution of the MP3 and CVMI stages
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 | Table 8: Correlation between peak-wise distribution of the CVMI stages and MP3 stages
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[Table 9] and [Figure 9] show the age-wise distribution of the MP3 stages. The correlation between the MP3 stages and the chronological age was found to be highly significant [Table 10] and [Table 11]. | Table 10: Correlation between the MP3 stages and chronological age in the boys
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 | Table 11: Correlation between the MP3 stages and the chronological age in the girls
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Regardless of the method used, there was a difference between males and females with regard to skeletal age assessment. It was observed that the commencement of the pre-peak stage in the boys corresponded to the age of 11.1±0.79 years and in the girls it corresponded to the age 8.75±0.96 years. The post-peak stages that represented completion of active growth corresponded to age 17.33±0.58 years in boys and 15.25±0.96 years in girls.
| Discussion | | |
During growth, every bone goes through a series of changes, which can be observed radiologically. The sequence of changes is relatively consistent for a given bone. The hand-wrist region has been the most frequently used area of the skeleton for growth assessment. The reason for its use is that many centers are available in this area of the skeleton, with changes occurring at different times and rates. [18],[19],[20],[21]
The time of occurrence of certain ossification events in relation to the growth spurt growth has also been frequently used to evaluate skeletal maturity. Although, with this method, prediction improves as the growth spurt approaches, there are limitations for early prediction; with the ossification events method, serial observations are required. The clinician often has only one radiograph available and thus cannot determine with any degree of reliability when the event has occurred. Also, individual variability in the duration of each stage does not allow a precise determination of where the child stands in relation to the peak growth velocity. Therefore, with this method, additional radiographs are needed in the course of treatment to improve the assessment of the peak growth velocity. [22]
Despite its limitations, the skeletal age has advantages over the chronologic age, particularly in those children whose growth is markedly advanced or retarded. It provides significant and valuable information about a child that can be obtained in no other way. It is useful in treatment planning of dentofacial deviations and in selecting and executing retention procedures or facial surgery. However, it should be regarded as a supplement to, and not as a substitute for, other diagnostic aids in the appraisal of growth. Although it is customary to take a radiograph of the entire hand and wrist area, not all ossification events or bone stages are used simultaneously at any time throughout the growth period. During early childhood the carpals are used for age assessment, while during late childhood and puberty the changes occurring in the metacarpals and phalanges provide a better information. [23]
This study was undertaken with the main aim of determining the reliability of the digital radiograph of the MP3 region as compared to the CVMI in the evaluation of skeletal maturity and to further categorize them peak-wise into prepeak, peak, and postpeak stages. According to our observations, the digital MP3 radiographic method of skeletal maturity assessment was reliable, with results comparable to the standard CVMI method. When the correlation between peak-wise distribution of the MP3 and CVMI stages were analyzed statistically and were found to be very highly significant
The results of this study will provide the clinician with an additional tool to help determine the growth potential in the adolescent patient. This was to be accomplished by using anatomic changes of the middle phalanx of the third finger, which was then compared with the known standard CVMI as observed on the lateral cephalometric radiograph to determine skeletal maturity. In the digital image of the middle phalanx of the third finger the clinician will have a reliable diagnostic tool to aid in formulating treatment options.
This method fulfilled the principle of 'as low as reasonably achievable' (ALARA), according to which the patient should be subjected to only that amount of radiation that is absolutely necessary for diagnostic purpose. [14] With an exposure time five times less than that used in the conventional approach, [12] this method showed great ability to provide a high-quality digitized radiographic images of the growth indicator under investigation.
The growth factor is a critical variable in dentofacial orthopedics. The treatment plan can vary from orthognathic surgery to extraction of teeth to nonextraction of teeth, depending on the growth factor. By examining the MP3 digital radiograph the clinician can now evaluate the skeletal maturity of the patient at that point in time and have a reasonable idea as to how much growth should be factored into the proposed treatment.
It is also possible to know the approximate chronological age through assessment of the skeletal maturity status. Dental radiographs can be used to take the radiographs of the MP3 region and by knowing the MP3 developmental status through these radiographs, it is possible to arrive at a conclusion regarding the age of the patient. Although this method can be used only in the adolescent and pubertal age-groups, it can be useful in medicolegal and forensic cases as it is a simple, noninvasive, and reliable method of age estimation.
It has long been recognized that a person's chronologic age does not necessarily correlate well with his maturational age. One may be skeletally accelerated or delayed in terms of maturational development. [6] There is wide variation in the chronologic age pertaining to the onset and duration of the adolescent growth spurt for both the boys and girls. Hunter [24] found boys to demonstrate a 4-year range of time for the onset of puberty, with a mean value of 12.8 years. In the female group, he identified a 5-year range of onset, with a mean value of 10.4 years. Therefore, girls usually begin their adolescent period an average of 2.4 years before boys. Because of this apparent variability between persons, longitudinal studies were initiated to more accurately assess individual maturational patterns. Gruelich and Pyle [18] prepared the first standards of maturational development using hand-wrist radiographs.
A study conducted by Madhu et al. [15] showed the correlation between the MP3 stages and chronological age in males and females. The reliability of age estimation using MP3 radiographs was established in their study, where they compared this method with other standard skeletal maturity assessment methods like hand-wrist radiographs and cervical vertebrae radiographs. The observations of the present study are in agreement with their study. They found that the prepeak period coincided with MP3F and MP3FG and is the ideal time to start a growth initiation procedure. The peak period of growth coincided with the MP3G stage, and treatment initiated during this period does not have a favorable prognosis. The post-peak stage was represented by the MP3H and MP3I stages and initiation of growth modification procedures are contraindicated in this stage.
The correlation between the chronological age of the subjects and the MP3 stages was assessed and the following observations were made: the prepeak stage initiation was achieved at 11.1±0.79 years in boys and at 8.75±0.96 years in girls. The peak period, corresponding to the MP3G stage, was achieved by 13.67±0.82 years in boys and by 12.67±1.03 years in girls. The completion of active growth was achieved at 17.33±0.58 years in boys and at 15.25±0.96 years in girls.
Some variations were observed in the results pertaining to the chronological age for the initiation and the completion of the active growth when compared to the study by Fishman [6] and Madhu et al.[15] In the study by Madhu et al., [15] the mean age for the initiation of active growth in boys was found to be 12.18±1.25 years and in girls it was 10.36±0.92 years, whereas in Fishman's [6] study the initiation of active growth was found to be at 11.01±1.22 years in boys and at 9.94±0.96 years in girls. The mean age for the completion of active growth was found to be at 17.00±0.00 years in boys and at 14.60±0.55 years in girls in the Madhu et al.[15] study, whereas in Fishman's [7] study completion of active growth was at 17.37±1.26 years in boys and at 16.07±1.25 years in girls. These variations could be attributable to the differences in the sample sizes and the geographical, cultural, climatic, and dietary differences, which may influence the growth and maturity of children.
A wide range of chronological values were determined for the boys and the girls. These values also demonstrated a significant difference between boys and girls in the initiation and completion of active growth.
As indicated through the observations in the present study, there were differences between male and female subjects irrespective of the method used for maturity assessment. This could have been caused by the differences in the maturation process between the sexes. Girls tended to achieve all the stages earlier than boys, indicating the need to initiate any kind of dentofacial orthopedic treatment earlier in girls than in boys.
| Conclusions | | |
- Digital radiography of the MP3 region is definitely a simple, reliable, cost-effective, and time-saving technique for the assessment of skeletal maturity.
- The digital MP3 radiographic method of skeletal maturity assessment was found to be highly comparable with the known standard method of cervical vertebrae maturity assessment (CVMA).
- The MP3 stages could be further categorized peak-wise into prepeak, (corresponding to MP3F and MP3FG), peak (corresponding to MP3G), and postpeak (corresponding to MP3H and MP3I) stages of pubertal growth spurt.
| References | | |
| 1. | Grave KC, Brown T. Skeletal ossification and the adolescent growth spurt. Am J Orthod 1997;69:611-9. 
|
| 2. | Singer J. Physiologic timing of Orthodontic treatment. Angle Orthod 1980;50:322-33.
[PUBMED] |
| 3. | Hagg U, Taranger J. Maturation indicators and pubertal growth spurt. Am J Orthod 1982;82:299-309.
|
| 4. | Hagg U, Taranger J. Menarche and voice change as indicators of pubertal growth spurt. Acta Odontol Scand 1980;38:179-86.
|
| 5. | Hagg U, Taranger J. Skeletal stages of the hand and wrist as indicators of the pubertal growth spurt. A Acta Odontol Scand 1980;38:187-200.
|
| 6. | Fishman LS. Chronological versus skeletal age, an evaluation of craniofacial growth. Angle Orthod 1979;49:181-9.
[PUBMED] |
| 7. | Hagg U, Matson L. Dental maturity as an indicator of chronological age: the accuracy and precision of three methods. Eur J Orthod 1985;7:25-35.
|
| 8. | Bjork A, Helm S. Prediction of the age of maximum pubertal growth in body height. Angle Orthod 1967;37:134-43.
|
| 9. | Green LJ. The interrelationship among height, weight and chronological age, dental and skeletal ages. Angle Orthod 1961;31:189-93.
|
| 10. | Hassel B, Farman AG. Skeletal maturation evaluation using cervical vertebrae. Am J Orthod Dentofacial Orthop 1995;107:58-66.
[PUBMED] |
| 11. | Tanner JM, Whitehouse RH, Marubini E, Resele LF. The adolescent growth spurt of boys and girls of the Harpenden growth study. Ann Hum Biol 1976;3:109-26.
[PUBMED] |
| 12. | Abdel Kader HM. Potential of digital dental radiography in recording the adductor sesamoid and the MP3 stages. Br J Orthod1999;26:291-4.
|
| 13. | Chapman SM. Ossification of the adductor sesamoid and the adolescent growth spurt. Angle Orthod 1972;42:236-45.
[PUBMED] |
| 14. | Abdel Kader HM. The reliability of the dental x-ray film in assessment of the MP3 stages of the pubertal growth spurt. Am J Orthod Dentofac Orthop 1998;114:427-9.
|
| 15. | Madhu S, Hegde AM, Munshi AK. The developmental stages of the middle phalanx of the third finger (MP3): Sole indicator in assessing the skeletal maturity? J Clin Pediatr Dent 2003;27:149-56.
[PUBMED] |
| 16. | Kucukkeles N, Acar A, Biren S, Arun T. Comparison between cervical vertebrae and hand-wrist maturation for the assessment of skeletal maturity. J Clin Pediatr Dent 1999;24:47-52.
[PUBMED] |
| 17. | Lamparski DJ. Skeletal age assessment utilizing cervical vertebrae [Master of dental science thesis]. Pittsburgh: University of Pittsburgh, School of Dental Medicine; 1972.
|
| 18. | Greulich WW, Pyle SI. Radiographic atlas of skeletal development of the hand - wrist. Stanford: Stanford University Press; 1959.
|
| 19. | Roche AF. Prepubertal and post pubertal growth. Duluth, Michigan; DB Cheek, 1975.
|
| 20. | National Center for Health Statistics. Rockville, Maryland: U.S. Department of Education Welfare; 1976 (series 11 no.160)
|
| 21. | Tanner JM, Whitestone RH, Marshall WA, Healy MJ, Goldstein H. Assessment of skeletal maturity and prediction of adult height .TW 2 method. London: Academic Press; 1975.
|
| 22. | Houston WJ. Relationships between skeletal maturity estimated from hand-wrist radiographs and the timing of the adolescent growth spurt. Eur J Orthod 1980;2:81-95.
[PUBMED] |
| 23. | Garn SM, Rohman CG. Variability in the order of ossification of the bony centers of the hand-wrist. Am J Phys Anthropol 1960;18:219-30.
|
| 24. | Hunter CJ. The correlation of facial growth with body height and skeletal maturation at adolescence. Angle Orthod 1966;36:44-54.
[PUBMED] |
Correspondence Address:
Sudhindra Baliga
Department of Pedodontics and Preventive Dentistry, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0970-9290.104947
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11] |
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