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Evaluation of Ricketts’ long-range growth prediction in Turkish children
ORIGINAL ARTICLE Evaluation of Ricketts’ long-range growth prediction in Turkish children ˙lken Kocadereli, DDS, PhD,a Aslı Ender Telli, DDS, PhDb Ankara, Turkey This study was conducted to evaluate Ricketts’ long-range growth prediction in Turkish children. Cephalometric analysis was conducted at baseline and 7 years for 40 children (20 girls, 20 boys) who received no orthodontic treatment. Ricketts’ long-range prediction was performed from baseline cephalograms and compared with actual growth 7 years later. Twenty-one cephalometric (12 angular and 9 linear) parameters were measured on actual and predicted tracings. The Pearson correlation coefficient was used to evaluate relationships between the “predicted” and “actual” measurements. Analysis was conducted on pooled data (males and females) and data by sex. There was a higher level of correlation for growth prediction in girls. Data indicate predictability in boys was greater for maxillary mandibular growth parameters. It was concluded that Ricketts’ long-range growth prediction may be helpful in improving treatment planning. Further work on accurate soft tissue and hard tissue growth prediction is indicated. (Am J Orthod Dentofacial Orthop 1999;115:515-20)
The amount and direction of facial growth have long been regarded as vital factors in determining the success or failure of orthodontic treatment.1-4 The ability to predict craniofacial growth accurately will improve the reliability of treatment planning.5,6 It is necessary for the orthodontist to make some type of growth prediction before initiating treatment. It is not possible to know where to position the teeth unless it is known where the bony bases will be during and at the end of treatment. A growth prediction is important not only in treatment planning and treatment provision, but it is equally important in the evaluation of prognosis during retention and postretention.7,8 Early attempts at growth prediction were based on the evaluation of certain craniofacial parameters. Such criteria as the mandibular plane angle,6,8,9 occlusal plane angle,10,11 Y axis,2,10,11 and mandibular morphology12,13 were proposed as predictors of future growth. Singer et al14 found that the clinical presence of a deep antegonial notch was indicative of a diminished mandibular growth potential and a vertically directed growth pattern. Several investigators reported that symphysis morphology could be used to predict the mandibular growth pattern.13,15-17 From Hacettepe University, Ankara, Turkey. aAssociate Professor, Department of Orthodontics, Faculty of Dentistry. bProfessor, Department of Orthodontics, Faculty of Dentistry. Reprint requests to: Dr. ˙lken Kocadereli, 15.Sokak No: 41/12, Bahçelievler 06490, Ankara, Turkiye. Copyright © 1998 by the American Association of Orthodontists. 0889-5406/98/$5.00 + 0 8/1/91529
Suzuki and Takahama18 found a high correlation between the craniofacial form of children and their parents. They suggested parental form be used in place of average growth curves when the growth of a child is to be determined. Mew 19 used an indicator line, which is measured from the tip of the nose to the tip of the upper left central incisor, to predict the direction of future facial growth. He found that the increased length of this indicator line suggested a vertical growth pattern. Although several previously investigated indicators may provide useful information on future growth patterns, no single parameter has been shown to enhance the orthodontist’s ability to predict the future growth. Evaluation of the visualized treatment objective (VTO) by Ricketts20 demonstrated growth and behavior of the mandible were predicted in 52 of the 55 patients, a 96% accuracy rate. In a further study conducted over 6 years, Ricketts21 reported, for the first time, the arcial growth of mandible. Ricketts22 advocated computer analysis for growth prediction thereby saving time in complex data manipulation to retrieve the information in a clinically useful form. A number of other studies23-31 have attempted to achieve reliable growth prediction. Because of the biological uncertainties involved, orthodontic treatment is essentially a game of strategy against nature. The Ricketts’ approach to growth prediction is based on the individual pattern with the addition of a variety of constants representing mean values that have been available as a result of diagnostic analysis over several years.32-35 515
516 Kocadereli and Telli
The present study was conducted to evaluate the accuracy of Ricketts’ long-range growth prediction in Turkish children. SUBJECTS AND METHOD
The study sample consisted of 40 children (20 girls, 20 boys) who received no orthodontic treatment after referral to the Orthodontic Department, Faculty of Dentistry, at Hacettepe University. The baseline average age was 9.2 ± 0.82 years for girls and 9.3 ± 0.92 years for boys. Cephalometric headfilms of the sample group were taken at natural head position at baseline and 7 years. All growth prediction procedures were conducted manually by the same orthodontist. The Ricketts’ cephalometric analysis36 was applied to the baseline headfilms, thus growth direction and cephalometric parameters of the subjects were evaluated. Ricketts’ long-range growth prediction37 was applied in four stages: 1. Prediction of mandibular arcial growth: • Determination of EVA point • Determination of mandibular arc (MARC) • Determination of new symphysis • Determination of new Murray point • Determination of sigmoid curvature • Prediction of gonial point • Completion of mandibular prediction 2. Prediction of cranial base: • Adaptation of the mandibula • Determination of new Frankfurt Horizontal • Tracing new Basion-Nasion line • Prediction of Nasion • Prediction of Basion 3. Prediction of maxilla: • Determination of ANS • Determination of PNS • Determination of Point A • Tracing new Apo line • Determination of new occlusal plane 4. Prediction of dentition and soft tissues: • Dentition Prediction of lower central position Prediction of upper central position Prediction of lower molar position Prediction of upper molar position • Soft tissue Prediction of nose Prediction of nose tip Prediction of upper lip Prediction of lower lip Prediction of soft tissue pogonion
For each subject, linear (Fig 1) and angular (Fig 2) parameters were measured on the tracings of the cephalograms taken at 7 years and compared with “pre-
American Journal of Orthodontics and Dentofacial Orthopedics May 1999
dicted” cephalometric tracing constructed following the baseline cephalometric measurements. The measured parameters included: 1. Convexity (mm) 2. Lower face height (dg) 3. Condylion-Point A (mm) 4. Condylion-Gnathion (mm) 5. Nasolabial angle (dg) 6. Lower lip to E plane (mm) 7. Upper lip length (mm) 8. Facial depth (dg) 9. Facial axis (dg) 10. Maxillary depth (dg) 11. Maxillary height (dg) 12. Palatal plane-Frankfurt Horizontal plane (dg) 13. Mandibular plane-Frankfurt Horizontal plane (dg) 14. Basion-Nasion-Point A (BNA)(dg) 15. Cranial deflection (dg) 16. Cranial length anterior (mm) 17. Ramus height (CF-Go) (mm) 18. Ramus-Xi position (dg) 19. Porion to PTV (mm) 20. Mandibular arc angle (dg) 21. Corpus length (mm) RESULTS
The Pearson Product Correlation Coefficient (PPCC) was used to evaluate the relationship between “predicted” and “actual” parameters (Tables I, II, and III). In this study, the PPCC of the Ricketts’ longrange growth prediction method was found to be greater than 0.7 for the following measurements: lower face height, condylion-point A, facial axis, mandibular arc angle, mandibular plane-FH plane angle, and BNA angle for a pooled male and female subject sample (Table I). The correlation coefficient was between 0.5 to 0.69 for the following measurements: convexity, lower lip-E plane, upper lip length, facial depth, maxillary depth, palatal plane-FH plane angle, cranial length, ramus height and corpus length in Turkish children (male and female) (Table I). The PPCC was found less than 0.35% for condyliongnathion, nasolabial angle, maxillary height, cranial deflection, ramus-Xi position and porion-PTV measurements (male and female) (Table I). In view of the poor correlation noted for a number of parameters measured when analysis was conducted on the pooled male and female data, it was decided that further analysis was indicated by sex. The “predicted” and “actual” values of some parameters varied between girls and boys.
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Fig 1. Linear measurements: 1, Convexity; 2, CondylionPoint A; 3, Condylion-Gnathion; 4, Lower lip to E plane; 5, Upper lip length; 6, Cranial length (anterior) (CC-Na); 7, Ramus height (CF-Go); 8, Porion to PTV; 9, Corpus length (Xi-Pm).
Girls Group
Fourteen of the 21 parameters showed statistically significant correlations between “predicted” and “actual” measurements (P < .05) (Table II). The PPCC of the Ricketts’ long-range growth prediction method was found greater than 0.89 for 8 of the 21 parameters. The correlation was 0.90 for mandibular plane-FH plane angle, 0.88 for mandibular arc angle, 0.85 for convexity and facial axis , 0.84 for palatal plane-FH plane angle, 0.81 for lower face height, upper lip length, and ramus height (Table II). The PPCC was found 0.72 for condylion-point A, and between 0.50 and 0.69 for the following measurements: condyliongnathion, nasolabial angle, lower lip-E plane, and cranial length anterior. Ramus-Xi position, corpus length, porion to PTV, cranial deflection, BNA angle, maxillary height, and maxillary depth were the poorly predicted measurements with a PPCC varying between 0.30 and 0.48 (Table II). Boys Group
Twelve of the 21 parameters showed a poor correlation between “predicted” and “actual” measurements (P > .05) (Table III). In the boys group, some of the mandibular and maxillary parameters proved to
Fig 2. Angular measurements: 1, Lower face height; 2, Nasolabial angle; 3, Facial depth; 4, Facial axis; 5, Maxillary depth; 6, Maxillary height; 7, Palatal plane-FH plane; 8, Mandibular plane-FH plane; 9, BNA angle; 10, Cranial deflection; 11, Ramus-Xi position; 12, Mandibular arc angle.
be the most accurately predicted of all measurements. The PPCC was 0.89 for BNA angle, 0.73 for facial axis, 0.71 for lower face height and mandibular arc angles, and 0.70 for lower lip-E plane. The facial depth, maxillary depth, and maxillary height had smaller PPCC values varying between 0.56 and 0.64 Convexity, condylion-gnathion, nasolabial angle, upper lip length, palatal plane-FH plane angle, mandibular plane-FH plane angle, cranial deflection, cranial length anterior, ramus height, ramus-Xi position, porion to PTV, and corpus length were all poorly predicted measurements with a PPCC varying between −0.2 and 0.47 (P > .05) (Table III). These figures suggest that the Ricketts’ long-range manual growth prediction is accurate in forecasting some aspects of growth. DISCUSSION
In order to estimate the required movement of the upper and lower dentition, it is necessary to calculate the positions of the upper and lower jaws at the end of treatment that, in itself, requires a long-range prediction of forward growth of the mandible.31 The principal aim of this study was to determine if the Ricketts’ long-range growth prediction can predict
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American Journal of Orthodontics and Dentofacial Orthopedics May 1999
Table I. Pearson correlation of Turkish children Skeletal measurements n = 40 Convexity (mm) Lower face height (dg) Condylion-point A (mm) Condylion-Gnathion (mm) Soft tissue measurements Nasolabial angle (dg) Lower lip-E plane (mm) Upper lip length (mm) Jaw to cranium Facial depth (dg) Facial axis (dg) Maxillary depth (dg) Maxillary height (dg) Palatal plane-FH plane (dg) Mandibular plane-FH plane (dg) BNA angle (dg) Internal structures Cranial deflection (dg) Cranial length (anterior)(mm) Ramus height (CF-Go)(mm) Ramus-Xi position (dg) Porion to PTV (mm) Mandibular arc angle (dg) Corpus length (mm)
Correlation
Significance
0.619 0.770 0.703 0.104
0.000 0.000 0.000 0.584
0.327 0.667 0.593
0.078 0.000 0.001
0.678 0.790 0.538 0.352 0.623 0.810 0.700
0.000 0.000 0.002 0.056 0.000 0.000 0.000
-0.119 0.656 0.608 0.187 0.326 0.819 0.530
0.533 0.000 0.000 0.321 0.079 0.000 0.003
*** *** ***
*** *** *** *** ** *** *** ***
*** ***
*** ***
Table II. Pearson correlation of Turkish girls Skeletal measurements n = 20
Correlation
Convexity (mm) Lower face height (dg) Condylion-point A (mm) Condylion-Gnathion (mm) Soft tissue measurements Nasolabial angle (dg) Lower lip-E plane (mm) Upper lip length (mm) Jaw to cranium Facial depth (dg) Facial axis (dg) Maxillary depth (dg) Maxillary height (dg) Palatal plane-FH plane (dg) Mandibular plane-FH plane (dg) BNA angle (dg) Internal structures Cranial deflection (dg) Cranial length (anterior)(mm) Ramus height (CF-Go)(mm) Ramus-Xi position (dg) Porion to PTV (mm) Mandibular arc angle (dg) Corpus length (mm)
the amount and direction of future craniofacial growth in Turkish children taking into account the current stage of development of a subject. If this process predicts growth accurately, then it could be used as part of
Significance
0.847 0.814 0.715 0.580
0.000 0.000 0.003 0.024
*** *** *** **
0.567 0.575 0.807
0.028 0.025 0.000
** ** ***
0.728 0.848 0.462 0.140 0.840 0.902 0.478
0.002 0.000 0.083 0.618 0.000 0.000 0.072
*** ***
-0.272 0.592 0.804 0.296 0.070 0.880 0.064
0.327 0.020 0.000 0.284 0.805 0.000 0.822
*** ***
** ***
***
the diagnostic evaluation of children for orthodontic treatment planning. Of the 21 parameters evaluated in this study, 15 showed statistically significant (P < .05) correlation
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Table III. Pearson correlation of Turkish boys Skeletal measurements n = 20 Convexity (mm) Lower face height (dg) Condylion-point A (mm) Condylion-Gnathion (mm) Soft tissue measurements Nasolabial angle (dg) Lower lip-E plane (mm) Upper lip length (mm) Jaw to cranium Facial depth (dg) Facial axis (dg) Maxillary depth (dg) Maxillary height (dg) Palatal plane-FH plane (dg) Mandibular plane-FH plane (dg) BNA angle (dg) Internal structures Cranial deflection (dg) Cranial length (anterior)(mm) Ramus height (CF-Go)(mm) Ramus-Xi position (dg) Porion to PTV (mm) Mandibular arc angle (dg) Corpus length (mm)
between the “predicted” and “actual” measurements for the pooled sample group (Table I). The predicted and actual values of some parameters varied between Turkish boys and girls. Although the convexity, upper lip length, mandibular plane-FH plane angle, and ramus height measurements were well predicted in the girls group, they were poorly predicted in the boys group. Soft tissue profile is one of the most critical areas of interest in the evaluation of a potential treatment plan. In the present study, the upper lip position was the only parameter related to the soft tissue profile that was accurately predicted in the boys group, however, in the girls group the lower lip was the only accurately predicted soft tissue parameter. The predicted soft tissue profiles of the nose and upper lip were found to be more retrusive than the actual case in the Turkish boy sample in accordance with Thames et al38 in RMDS prediction. Enacar39 applied Ricketts’ long-range growth prediction for a period of four years to 32 Turkish adolescents with no orthodontic treatment. He concluded that there was high correlation between the “predicted” and “actual” measurements. Mandibular parameters were accurately predicted. The findings in this study of greater mandibular predictability is in agreement with Enacar.39 The PPCC was 0.81 for mandibular plane-FH plane angle, 0.819 for mandibular arc angle (Table I) (P<.001). In a study by Saˇgdıç and Uzel40 Ricketts’ short-
Correlation
Significance
0.446 0.710 0.701 0.268
0.095 0.003 0.004 0.335
*** ***
0.121 0.701 0.149
0.667 0.004 0.595
***
0.643 0.730 0.599 0.555 0.084 0.432 0.889
0.010 0.002 0.018 0.032 0.765 0.108 0.000
0.236 0.452 0.362 −0.161 0.466 0.706 0.321
0.396 0.090 0.185 0.566 0.080 0.003 0.243
** *** ** **
***
***
range growth prediction was used over a period of 2 years in 27 extraction and 33 nonextraction cases. Both were found to be 61.53% accurate. Schulhof and Bagha31 found the Ricketts’ short-range RMDS computer prediction method to be 73% accurate in predicting the mandibular growth. They found the RMDS computer program more successful in predicting the maxillary growth with an accuracy of 74% and mandibular growth with an accuracy of 78%. CONCLUSION
The Ricketts’ long-range growth prediction is a helpful method when used as a tool in orthodontic treatment planning. Ricketts’ long-range growth prediction applied to Turkish children showed statistically significantly higher correlations between predicted and actual measurements in: • Convexity, lower face height, condylion-point A, upper lip length, facial depth, facial axis, palatal plane-FH plane angle, mandibular plane-FH plane angle, ramus height, and mandibular arc angle in girls • Lower face height, nasolabial angle, porion to PTV, ramus-Xi position, cranial deflection, condylionpoint A, lower lip-E plane, facial axis, BNA angle, and mandibular arc angle in boys. We would like to thank to Surgeon Commander Colin Priestland Royal Navy for his kind help in preparation of the manuscript.
520 Kocadereli and Telli
REFERENCES 1. Björk A. The significance of growth changes in facial pattern and their relationship to changes in occlusion. Dental Record 1951;71:197-208. 2. Downs WB. Variations in facial relationships: their significance in treatment and prognosis. Am J Orthod 1948;34:812-40. 3. Brodie AG, Downs WB, Goldstein A, Meyer E. Cephalometric appraisal of orthodontic results: a preliminary report. Angle Orthod 1938;8:261-5. 4. Björk A, Skieller V. Facial development and tooth eruption. Am J Orthod 1972;49:339-82. 5. Burstone CJ. Process of maturation and growth prediction. Am J Orthod 1963;49:907-19. 6. Ricketts RM. Planning treatment on the basis of the facial pattern and an estimate of its growth. Angle Orthod 1957;27:14-37. 7. Mitchell DL, Jordan JF, Ricketts RM. Arcial growth with metallic implants in mandibular growth prediction. Am J Orthod 1975;68:655-9. 8. Tweed CH. Treatment planning and therapy in the mixed dentition. Am J Orthod 1963;49:881-906. 9. Tweed CH. The Frankfort mandibular plane angle in orthodontic diagnosis, classification, treatment planning and prognosis. Am J Orthod Oral Surgery 1946;32:175-221. 10. Ricketts RM. Foundation for cephalometric communication. Am J Orthod 1960;46:330-57. 11. Ricketts RM. Cephalometric analysis and synthesis. Angle Orthod 1961;31:141-56. 12. Björk A. Variations in the growth pattern of the human mandible: longitudinal radiographic study by the implant method. J Dent Res 1963;42:400-11. 13. Björk A. Prediction of mandibular growth rotation. Am J Orthod 1969;55:585-98. 14. Singer CP, Mamandras AH, Hunter WS. The depth of the mandibular antegonial notch as an indicator of mandibular growth potential. Am J Orthod Dentofacial Orthop 1987;91:117-24. 15. Johnston EL. The Frankfort mandibular plane angle and the facial pattern. Am J Orthod 1950;36:516-33. 16. Ricketts RM. Cephalometric synthesis. Am J Orthod 1960;46:647-73. 17. Aki T, Nanda RS, Currier FG, Nanda SK. Assessment of symphysis morphology as a predictor of the direction of mandibular growth. Am J Orthod Dentofacial Orthop 1994;106:60-9. 18. Suzuki A, Takahama Y. Parental data used to predict growth of craniofacial form. Am J Orthod Dentofacial Orthop 1991;90:107-19. 19. Mew J. Suggestions for forecasting and monitoring facial growth. Am J Orthod Dentofacial Orthop 1993;104:105-20. 20. Ricketts RM. Facial and denture changes during orthodontic treatment as analysed from the temporomandibular joint. Am J Orthod 1955;41:163-79.
American Journal of Orthodontics and Dentofacial Orthopedics May 1999
21. Ricketts RM. The discovery of a law of arcial growth of the mandible. In Proceedings of the Foundation of Orthodontic Research, 1971;31-52. 22. Ricketts RM. Editorial response “Truth in orthodontic beliefs.” JCO 1993;27:612-30. 23. Mauchamps O, Sassouni V. Growth and prediction of the skeletal and soft tissue profiles. Am J Orthod 1973;64:83-94. 24. Riolo ML, Moyers RE, McNamara JA, Hunter WS. An atlas of craniofacial growth. Center for Human Growth and Development. University of Michigan, Ann Arbor, Michigan, 1974. 25. Broadbent BH Snr, Broadbent BH Jr, Golden WG. Bolton standards for dentofacial developmental growth. St. Louis: CV Mosby Co; 1975; p. 136-61. 26. Johnston LE. A simplified approach to prediction. Am J Orthod 1975;67:253-7. 27. Popovich F, Thompson GW. Craniofacial templates for orthodontic case analysis. Am J Orthod 1977;71:406-20. 28. Skieller V, Björk A, Linde-Hansen T. Prediction of mandibular growth rotation evaluated from a longitudinal implant sample. Am J Orthod 1984;86:359-70. 29. Magnes WB. The mini-visualized treatment objective. Am J Orthod 1987;91:361-74. 30. Buschang PH, Tanguay R, La Palme L, Demirjian A. Mandibular growth prediction: mean growth increments versus mathematical models. Eur J Orthod 1990;12:290-6. 31. Schulhof RJ, Bagha L. A statistical evaluation of the Ricketts and Johnston growthforecasting methods. Am J Orthod 1975;67:258-76. 32. Ricketts RM. A four-step method to distinguish orthodontic changes from natural growth. JCO 1975;9:208-28. 33. JCO Interviews, Dr. Robert M. Ricketts on growth prediction. JCO 1975;9:277-96. 34. JCO Interviews, Dr. Robert M. Ricketts on growth prediction, Part 2. JCO 1975;9:340-62. 35. JCO Interviews, Dr. Robert M. Ricketts on growth prediction, Part 3. JCO 1975;9:420-34. 36. Ricketts RM, Bench RW, Gugino CF, Hilgers JJ, Schulhof RJ. Bioprogressive therapy, Rocky Mountain Co. 1979. 37. Ricketts RM. A principle of archial growth of the mandible. Angle Orthod 1972;42:368-85. 38. Thames TL, Sinclair PM, Alexander RG. The accuracy of computerized growth prediction in Class II high angle cases. Am J Orthod 1985;87:398-405. 39. Enacar A. Ricketts’in “mandibulanın arkial büyümesi” kuramının ve uzun süreli tahmin yönteminin ülkemiz bireylerinde deerlendirilmesi (longitudinal arastırma). Büyüme Gelisim ve Ortodonti, Tübitak Yayın Daıtım Daire Baskanligi, Ankara, 1991. 40. Saˇgdıç D, Uzel S. Ricketts sefalometrik büyüme tahmin yönteminin ortodontik olgulara uygulanarak irdelenmesi. Büyüme Gelisim ve Ortodonti, Tübitak Yayın Daˇgıtım Daire Baskanligi, Ankara,1991.
The amount and direction of facial growth have long been regarded as vital factors in determining the success or failure of orthodontic treatment.1-4 The ability to predict craniofacial growth accurately will improve the reliability of treatment planning.5,6 It is necessary for the orthodontist to make some type of growth prediction before initiating treatment. It is not possible to know where to position the teeth unless it is known where the bony bases will be during and at the end of treatment. A growth prediction is important not only in treatment planning and treatment provision, but it is equally important in the evaluation of prognosis during retention and postretention.7,8 Early attempts at growth prediction were based on the evaluation of certain craniofacial parameters. Such criteria as the mandibular plane angle,6,8,9 occlusal plane angle,10,11 Y axis,2,10,11 and mandibular morphology12,13 were proposed as predictors of future growth. Singer et al14 found that the clinical presence of a deep antegonial notch was indicative of a diminished mandibular growth potential and a vertically directed growth pattern. Several investigators reported that symphysis morphology could be used to predict the mandibular growth pattern.13,15-17 From Hacettepe University, Ankara, Turkey. aAssociate Professor, Department of Orthodontics, Faculty of Dentistry. bProfessor, Department of Orthodontics, Faculty of Dentistry. Reprint requests to: Dr. ˙lken Kocadereli, 15.Sokak No: 41/12, Bahçelievler 06490, Ankara, Turkiye. Copyright © 1998 by the American Association of Orthodontists. 0889-5406/98/$5.00 + 0 8/1/91529
Suzuki and Takahama18 found a high correlation between the craniofacial form of children and their parents. They suggested parental form be used in place of average growth curves when the growth of a child is to be determined. Mew 19 used an indicator line, which is measured from the tip of the nose to the tip of the upper left central incisor, to predict the direction of future facial growth. He found that the increased length of this indicator line suggested a vertical growth pattern. Although several previously investigated indicators may provide useful information on future growth patterns, no single parameter has been shown to enhance the orthodontist’s ability to predict the future growth. Evaluation of the visualized treatment objective (VTO) by Ricketts20 demonstrated growth and behavior of the mandible were predicted in 52 of the 55 patients, a 96% accuracy rate. In a further study conducted over 6 years, Ricketts21 reported, for the first time, the arcial growth of mandible. Ricketts22 advocated computer analysis for growth prediction thereby saving time in complex data manipulation to retrieve the information in a clinically useful form. A number of other studies23-31 have attempted to achieve reliable growth prediction. Because of the biological uncertainties involved, orthodontic treatment is essentially a game of strategy against nature. The Ricketts’ approach to growth prediction is based on the individual pattern with the addition of a variety of constants representing mean values that have been available as a result of diagnostic analysis over several years.32-35 515
516 Kocadereli and Telli
The present study was conducted to evaluate the accuracy of Ricketts’ long-range growth prediction in Turkish children. SUBJECTS AND METHOD
The study sample consisted of 40 children (20 girls, 20 boys) who received no orthodontic treatment after referral to the Orthodontic Department, Faculty of Dentistry, at Hacettepe University. The baseline average age was 9.2 ± 0.82 years for girls and 9.3 ± 0.92 years for boys. Cephalometric headfilms of the sample group were taken at natural head position at baseline and 7 years. All growth prediction procedures were conducted manually by the same orthodontist. The Ricketts’ cephalometric analysis36 was applied to the baseline headfilms, thus growth direction and cephalometric parameters of the subjects were evaluated. Ricketts’ long-range growth prediction37 was applied in four stages: 1. Prediction of mandibular arcial growth: • Determination of EVA point • Determination of mandibular arc (MARC) • Determination of new symphysis • Determination of new Murray point • Determination of sigmoid curvature • Prediction of gonial point • Completion of mandibular prediction 2. Prediction of cranial base: • Adaptation of the mandibula • Determination of new Frankfurt Horizontal • Tracing new Basion-Nasion line • Prediction of Nasion • Prediction of Basion 3. Prediction of maxilla: • Determination of ANS • Determination of PNS • Determination of Point A • Tracing new Apo line • Determination of new occlusal plane 4. Prediction of dentition and soft tissues: • Dentition Prediction of lower central position Prediction of upper central position Prediction of lower molar position Prediction of upper molar position • Soft tissue Prediction of nose Prediction of nose tip Prediction of upper lip Prediction of lower lip Prediction of soft tissue pogonion
For each subject, linear (Fig 1) and angular (Fig 2) parameters were measured on the tracings of the cephalograms taken at 7 years and compared with “pre-
American Journal of Orthodontics and Dentofacial Orthopedics May 1999
dicted” cephalometric tracing constructed following the baseline cephalometric measurements. The measured parameters included: 1. Convexity (mm) 2. Lower face height (dg) 3. Condylion-Point A (mm) 4. Condylion-Gnathion (mm) 5. Nasolabial angle (dg) 6. Lower lip to E plane (mm) 7. Upper lip length (mm) 8. Facial depth (dg) 9. Facial axis (dg) 10. Maxillary depth (dg) 11. Maxillary height (dg) 12. Palatal plane-Frankfurt Horizontal plane (dg) 13. Mandibular plane-Frankfurt Horizontal plane (dg) 14. Basion-Nasion-Point A (BNA)(dg) 15. Cranial deflection (dg) 16. Cranial length anterior (mm) 17. Ramus height (CF-Go) (mm) 18. Ramus-Xi position (dg) 19. Porion to PTV (mm) 20. Mandibular arc angle (dg) 21. Corpus length (mm) RESULTS
The Pearson Product Correlation Coefficient (PPCC) was used to evaluate the relationship between “predicted” and “actual” parameters (Tables I, II, and III). In this study, the PPCC of the Ricketts’ longrange growth prediction method was found to be greater than 0.7 for the following measurements: lower face height, condylion-point A, facial axis, mandibular arc angle, mandibular plane-FH plane angle, and BNA angle for a pooled male and female subject sample (Table I). The correlation coefficient was between 0.5 to 0.69 for the following measurements: convexity, lower lip-E plane, upper lip length, facial depth, maxillary depth, palatal plane-FH plane angle, cranial length, ramus height and corpus length in Turkish children (male and female) (Table I). The PPCC was found less than 0.35% for condyliongnathion, nasolabial angle, maxillary height, cranial deflection, ramus-Xi position and porion-PTV measurements (male and female) (Table I). In view of the poor correlation noted for a number of parameters measured when analysis was conducted on the pooled male and female data, it was decided that further analysis was indicated by sex. The “predicted” and “actual” values of some parameters varied between girls and boys.
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Fig 1. Linear measurements: 1, Convexity; 2, CondylionPoint A; 3, Condylion-Gnathion; 4, Lower lip to E plane; 5, Upper lip length; 6, Cranial length (anterior) (CC-Na); 7, Ramus height (CF-Go); 8, Porion to PTV; 9, Corpus length (Xi-Pm).
Girls Group
Fourteen of the 21 parameters showed statistically significant correlations between “predicted” and “actual” measurements (P < .05) (Table II). The PPCC of the Ricketts’ long-range growth prediction method was found greater than 0.89 for 8 of the 21 parameters. The correlation was 0.90 for mandibular plane-FH plane angle, 0.88 for mandibular arc angle, 0.85 for convexity and facial axis , 0.84 for palatal plane-FH plane angle, 0.81 for lower face height, upper lip length, and ramus height (Table II). The PPCC was found 0.72 for condylion-point A, and between 0.50 and 0.69 for the following measurements: condyliongnathion, nasolabial angle, lower lip-E plane, and cranial length anterior. Ramus-Xi position, corpus length, porion to PTV, cranial deflection, BNA angle, maxillary height, and maxillary depth were the poorly predicted measurements with a PPCC varying between 0.30 and 0.48 (Table II). Boys Group
Twelve of the 21 parameters showed a poor correlation between “predicted” and “actual” measurements (P > .05) (Table III). In the boys group, some of the mandibular and maxillary parameters proved to
Fig 2. Angular measurements: 1, Lower face height; 2, Nasolabial angle; 3, Facial depth; 4, Facial axis; 5, Maxillary depth; 6, Maxillary height; 7, Palatal plane-FH plane; 8, Mandibular plane-FH plane; 9, BNA angle; 10, Cranial deflection; 11, Ramus-Xi position; 12, Mandibular arc angle.
be the most accurately predicted of all measurements. The PPCC was 0.89 for BNA angle, 0.73 for facial axis, 0.71 for lower face height and mandibular arc angles, and 0.70 for lower lip-E plane. The facial depth, maxillary depth, and maxillary height had smaller PPCC values varying between 0.56 and 0.64 Convexity, condylion-gnathion, nasolabial angle, upper lip length, palatal plane-FH plane angle, mandibular plane-FH plane angle, cranial deflection, cranial length anterior, ramus height, ramus-Xi position, porion to PTV, and corpus length were all poorly predicted measurements with a PPCC varying between −0.2 and 0.47 (P > .05) (Table III). These figures suggest that the Ricketts’ long-range manual growth prediction is accurate in forecasting some aspects of growth. DISCUSSION
In order to estimate the required movement of the upper and lower dentition, it is necessary to calculate the positions of the upper and lower jaws at the end of treatment that, in itself, requires a long-range prediction of forward growth of the mandible.31 The principal aim of this study was to determine if the Ricketts’ long-range growth prediction can predict
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Table I. Pearson correlation of Turkish children Skeletal measurements n = 40 Convexity (mm) Lower face height (dg) Condylion-point A (mm) Condylion-Gnathion (mm) Soft tissue measurements Nasolabial angle (dg) Lower lip-E plane (mm) Upper lip length (mm) Jaw to cranium Facial depth (dg) Facial axis (dg) Maxillary depth (dg) Maxillary height (dg) Palatal plane-FH plane (dg) Mandibular plane-FH plane (dg) BNA angle (dg) Internal structures Cranial deflection (dg) Cranial length (anterior)(mm) Ramus height (CF-Go)(mm) Ramus-Xi position (dg) Porion to PTV (mm) Mandibular arc angle (dg) Corpus length (mm)
Correlation
Significance
0.619 0.770 0.703 0.104
0.000 0.000 0.000 0.584
0.327 0.667 0.593
0.078 0.000 0.001
0.678 0.790 0.538 0.352 0.623 0.810 0.700
0.000 0.000 0.002 0.056 0.000 0.000 0.000
-0.119 0.656 0.608 0.187 0.326 0.819 0.530
0.533 0.000 0.000 0.321 0.079 0.000 0.003
*** *** ***
*** *** *** *** ** *** *** ***
*** ***
*** ***
Table II. Pearson correlation of Turkish girls Skeletal measurements n = 20
Correlation
Convexity (mm) Lower face height (dg) Condylion-point A (mm) Condylion-Gnathion (mm) Soft tissue measurements Nasolabial angle (dg) Lower lip-E plane (mm) Upper lip length (mm) Jaw to cranium Facial depth (dg) Facial axis (dg) Maxillary depth (dg) Maxillary height (dg) Palatal plane-FH plane (dg) Mandibular plane-FH plane (dg) BNA angle (dg) Internal structures Cranial deflection (dg) Cranial length (anterior)(mm) Ramus height (CF-Go)(mm) Ramus-Xi position (dg) Porion to PTV (mm) Mandibular arc angle (dg) Corpus length (mm)
the amount and direction of future craniofacial growth in Turkish children taking into account the current stage of development of a subject. If this process predicts growth accurately, then it could be used as part of
Significance
0.847 0.814 0.715 0.580
0.000 0.000 0.003 0.024
*** *** *** **
0.567 0.575 0.807
0.028 0.025 0.000
** ** ***
0.728 0.848 0.462 0.140 0.840 0.902 0.478
0.002 0.000 0.083 0.618 0.000 0.000 0.072
*** ***
-0.272 0.592 0.804 0.296 0.070 0.880 0.064
0.327 0.020 0.000 0.284 0.805 0.000 0.822
*** ***
** ***
***
the diagnostic evaluation of children for orthodontic treatment planning. Of the 21 parameters evaluated in this study, 15 showed statistically significant (P < .05) correlation
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Table III. Pearson correlation of Turkish boys Skeletal measurements n = 20 Convexity (mm) Lower face height (dg) Condylion-point A (mm) Condylion-Gnathion (mm) Soft tissue measurements Nasolabial angle (dg) Lower lip-E plane (mm) Upper lip length (mm) Jaw to cranium Facial depth (dg) Facial axis (dg) Maxillary depth (dg) Maxillary height (dg) Palatal plane-FH plane (dg) Mandibular plane-FH plane (dg) BNA angle (dg) Internal structures Cranial deflection (dg) Cranial length (anterior)(mm) Ramus height (CF-Go)(mm) Ramus-Xi position (dg) Porion to PTV (mm) Mandibular arc angle (dg) Corpus length (mm)
between the “predicted” and “actual” measurements for the pooled sample group (Table I). The predicted and actual values of some parameters varied between Turkish boys and girls. Although the convexity, upper lip length, mandibular plane-FH plane angle, and ramus height measurements were well predicted in the girls group, they were poorly predicted in the boys group. Soft tissue profile is one of the most critical areas of interest in the evaluation of a potential treatment plan. In the present study, the upper lip position was the only parameter related to the soft tissue profile that was accurately predicted in the boys group, however, in the girls group the lower lip was the only accurately predicted soft tissue parameter. The predicted soft tissue profiles of the nose and upper lip were found to be more retrusive than the actual case in the Turkish boy sample in accordance with Thames et al38 in RMDS prediction. Enacar39 applied Ricketts’ long-range growth prediction for a period of four years to 32 Turkish adolescents with no orthodontic treatment. He concluded that there was high correlation between the “predicted” and “actual” measurements. Mandibular parameters were accurately predicted. The findings in this study of greater mandibular predictability is in agreement with Enacar.39 The PPCC was 0.81 for mandibular plane-FH plane angle, 0.819 for mandibular arc angle (Table I) (P<.001). In a study by Saˇgdıç and Uzel40 Ricketts’ short-
Correlation
Significance
0.446 0.710 0.701 0.268
0.095 0.003 0.004 0.335
*** ***
0.121 0.701 0.149
0.667 0.004 0.595
***
0.643 0.730 0.599 0.555 0.084 0.432 0.889
0.010 0.002 0.018 0.032 0.765 0.108 0.000
0.236 0.452 0.362 −0.161 0.466 0.706 0.321
0.396 0.090 0.185 0.566 0.080 0.003 0.243
** *** ** **
***
***
range growth prediction was used over a period of 2 years in 27 extraction and 33 nonextraction cases. Both were found to be 61.53% accurate. Schulhof and Bagha31 found the Ricketts’ short-range RMDS computer prediction method to be 73% accurate in predicting the mandibular growth. They found the RMDS computer program more successful in predicting the maxillary growth with an accuracy of 74% and mandibular growth with an accuracy of 78%. CONCLUSION
The Ricketts’ long-range growth prediction is a helpful method when used as a tool in orthodontic treatment planning. Ricketts’ long-range growth prediction applied to Turkish children showed statistically significantly higher correlations between predicted and actual measurements in: • Convexity, lower face height, condylion-point A, upper lip length, facial depth, facial axis, palatal plane-FH plane angle, mandibular plane-FH plane angle, ramus height, and mandibular arc angle in girls • Lower face height, nasolabial angle, porion to PTV, ramus-Xi position, cranial deflection, condylionpoint A, lower lip-E plane, facial axis, BNA angle, and mandibular arc angle in boys. We would like to thank to Surgeon Commander Colin Priestland Royal Navy for his kind help in preparation of the manuscript.
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