ORIGINAL RESEARCH Year : 2013  Volume : 24  Issue : 4  Page : 456463 Determination of craniofacial relation among the subethnic Indian population: A modified approach (vertical evaluation) A Sumathi Felicita, Shyamala Chandrasekar, KK Shanthasundari Department of Orthodontics, Saveetha Dental College, Chennai, India Correspondence Address: Aim: To measure the vertical linear cephalometric dimensions of the anterior and posterior segments of the craniofacial complex and establish ratios between vertical linear dimensions in subjects with normal occlusion, pleasing profile, and facial harmony. Setting and Sample Population: Department of Orthodontics, Saveetha University. Lateral cephalograms of 120 subjects of both sexes in the age group of 1728 years with normal occlusion belonging to Chennai, India. Materials and Methods: The vertical segments measured are anterior maxilla, posterior maxilla, and ramuscranial floor vertical. The facial heights were measured in the anterior and posterior region of the craniofacial complex. Establish ratios and proportions between the vertical segments and different facial heights. Results: In both the sexes, the ratio between anterior maxilla, posterior maxilla, and ramuscranial floor vertical is 1:1:1, PTFH:ATFH is 1:1, AUFH:ATFH is 2:5, ALFH:ATFH is 3:5, PUFH:PTFH is 1:2, PLFH:PTFH is 1:2, AUDH:ALDH is 2:3, and facial depth is 2:1. PUDH:PLDH is 7:9 in females and 3:4 in males. There was a statistically significant difference in posterior total facial height:anterior total facial height ratio between the two sexes with a «DQ»P«DQ» value of 95%. Conclusion: Thus, the anterior maxilla, posterior maxilla, and cranial floorramus vertical composite are in dimensional balance in subjects with normal occlusion and facial harmony. This analysis helps to identify skeletal deviations in size and position in the vertical dimension and allows the clinician to outline an appropriate treatment.
Materials and Methods The sample for the present study consists of 120 patients, 60 males and 60 females from the local population staying in Chennai city, within the age group ranging from 17 to 28 years with Tamil as their mother tongue. The previous paper [31] explains the inclusion and exclusion criteria used in the study, method of standardization of lateral cephalograms, and the reference points and reference planes used. Linear dimensions of specific anatomical segments were measured parallel to the posterior maxillary plane vertical with the mandibular plane, palatal plane, functional occlusal plane, and cranial base reference plane as limiting planes [Figure 1]. A single operator measured all the parameters.{Figure 1} The vertical segments are anterior maxilla (A1), posterior maxilla (A2), and ramuscranial floor vertical (A3) [Figure 2]. {Figure 2} Measure these linear vertical parameters between the functional occlusal plane and cranial base reference plane parallel to the PM vertical. Measure the following facial heights to evaluate the anterior and posterior region of the craniofacial complex [Figure 3].{Figure 3} Total facial heightAnterior and posteriorAnterior facial height (ATFH)Upper and lowerPosterior facial heightUpper and lowerUpper dental height and lower dental heightAnterior and posterior.Correct all the linear measurements to the nearest 0.5 mm. Alphabetical and numerical code are given to the various parameters measured in the vertical direction as given below [Table 1]: A1A3Vertical anatomic segmentsF1F10Various facial and dental heights.{Table 1}Tabulate the measurements in a form analysis sheet. To find out whether a dimensional balance exists between the different segments, establish ratios between the different anatomic segments separately for males and females. Statistical evaluation of the various ratios reveals the presence or absence of sexual dimorphism. Randomly select 10 cephalograms (five each from males and females) and retrace after 3 weeks to evaluate intraexaminer variability in measurements. Statistical evaluation of these values shows reliability of measurement. Statistical analysis Dahlberg's method of error determination shows intraoperator error in measurement. Establish ratios between the different vertical parameters. Assess the level of significance for sexual dimorphism with independent 't' test. "P" value less than 0.05 is 95% significant, "P" value less than 0.01 is 99% significant, and "P" value less than 0.001 is 99.9% significant. The results obtained from the statistical evaluation were tabulated in [Table 2] and graphically represented in Graphs 19.{Table 2} [INLINE:1] Results [Table 1] and Graph 19 show the results obtained from statistical evaluation. Statistical evaluation of intraoperator error shows a ''r'' value in the range of 0.0006890.0792. This value indicates that the evaluation by the operator was consistent. "r" value nearing 1 indicates inconsistency. Vertical evaluation of the craniofacial complex consists of evaluation of vertical, anatomical segments, evaluation of facial heights and facial depth. Evaluation of vertical anatomical segment The ratio between anterior maxilla, posterior maxilla, and composite ramuscranial floor (A1:A2:A3) was in the ratio of 1.00056:1:1.05726 (1:1:1) for males and 1.00528:1:1.02687 (1:1:1) for females [Table 2] and Graph 1]. Evaluation of facial heights The ratio between anterior upper facial height (AUFH) and anterior total facial height (ATFH) was 0.41205:1 (2:5) for females and 0.40350:1 (2:5) for males [Table 2] and Graph 2]. The ratio between the anterior lower facial height (ALFH) and ATFH was 0.58488:1 (3:5) in females and 0.59307:1 (3:5) in males [Table 2] and Graph 3]. The ratio between the posterior upper facial height (PUFH) and posterior total facial height was found to be 0.51377:1 (1:2) in the females and 0.49878:1 (1:2) in males [Table 2] and Graph 4]. Similarly, the ratio between the posterior lower facial height and posterior total facial height was found to be 0.48379:1 (1:2) in the females and 0.49444:1 (1:2) in males [Table 2] and Graph 5]. The ratio between the posterior total facial height and ATFH was 0.91021:1 (1:1) in the females and 0.93812:1 (1:1) in the males. The "P" value was 0.010 and there was a statistically significant difference between males and females at a level of 99% [Table 2] and Graph 6]. The ratio between the anterior upper dental height and anterior lower dental height is 0.67360:1 (2:3) in females and 0.66730:1 (2:3) in males [Table 2] and Graph 7]. The ratio between the posterior upper dental height and posterior lower dental height was 0.77887:1 (7:9) in females and 0.76032:1 (3:4) in males [Table 2] and Graph 8]. Evaluation of facial depth The ratio between the total ATFH and facial depth at point B was 1.92527:1 (2:1) in females and 1.83943:1 (2:1) in males. There was no statistical significance between the males and females [Table 2] and Graph 9]. Discussion The rationale behind this analysis is that the vertical size of one bony segment can be compared with another specific bony segment of the same individual. In most of the conventional analysis, ATFH is measured between nasion and gnathion or menthon anteriorly and posterior facial height is measured between sella and gonion. These landmarks were excluded from the present study as sella and nasion are subject to anatomical variation. The vertical heights were measured anteriorly and posteriorly at the points of intersection of the cranial base, palatal, and mandibular plane with the anterior maxillary reference line and PM vertical reference line, respectively. It is evident from [Table 2] and Graph 1 that the vertical segments of the craniofacial complex evaluated in the present study had a mean ratio of 1.00528:1:1.02687 (1:1:1) in females and 1.00056:1:1.05726 (1:1:1) in males. This indicates that anterior maxilla, posterior maxilla, and cranial floorramus vertical composite are in dimensional balance. Any alteration in this ratio will help the clinician to locate whether the structural imbalance is in the anterior region in the nasomaxilla or in the posterior region in the posterior cranial floor/ramus composite. Evaluation of facial heights reveals various ratios for the different vertical parameters measured in the study. It can be seen from [Table 2] and Graph 2 that in the anterior region, the upper facial height with respect to total facial height had a proportional ratio of 2:5 in both males and females. A proportion of 3:5 was noted in both males and females between the ALFH and ATFH [Table 2] and Graph 3]. In the posterior segment, both the upper facial height to total facial height and lower facial height to total facial height was expressed as a proportion of 1:2 in both the sexes [Table 2] and Graphs 4 and 5]. These heights will help to localize the cause of vertical skeletal discrepancy between the anterior and posterior region. They also help to localize the deficiency to either the anterior or posterior part of maxillary skeletal base or the anterior or posterior part of the mandibular skeletal base. The ratio between ATFH and posterior facial height was 0.93812:1 (1:1) in females and 0.91021:1 (1:1) in males. Sexual dimorphism was noted with a statistical significance of 99.9% [Table 2] and Graph 6]. Evaluation of dentoalveolar relation in the vertical dimension revealed a ratio of 2:3 between anterior upper dental height to anterior lower dental height in both sexes [Table 2] and Graph 7]. The ratio of posterior upper dental height to posterior lower dental height was found to be 0.77887:1 (7:9) and 0.76032:1 (3:4) in males and females, respectively [Table 2] and Graph 8]. The ratio of ATFH to the facial depth at point B was found to be 1.92527:1 (2:1) in females and 1.83943 (2:1) in males [Table 2] and Graph 9]. An alteration in this ratio would suggest the retrusive or protrusive position of the mandible. These ratios established in the present study for the abovementioned vertical heights are not comparable to the values expressed by other investigators [8],[32],[33],[34],[35],[36] due to the difference in the anatomic landmarks chosen and the method of expression of the values. Di Paolo [8],[9],[10],[11] measured ALFH from the point of projection of A point on the palatal plane to the projection of B point on the mandibular plane. The posterior facial height was measured between projection of J point onto the mandibular plane and projection of Pterogomaxillary fissure to the palatal plane. He reported a ratio of 1:1.21 for ALFH:AUFH and 1:1.52 for PLFH:ALFH. Scheideman et al., [37] analyzed facial profile and proportionality of 56 adult Caucasians with class I skeletal and dental relationships and good vertical facial proportion with a computerized craniofacial model. Measurements were made relative to SellaNasion registered at nasion. He reported that the lower facial height (ANSMe) was 55.5% of the total facial height (NMe). These measurements were very close to the values of Goldman 54.6% (ANSGn), Weinberg and Kronman [32] 54.8% (ANSGn), Schudy [33] 56.5%(ANSGn), and Broadbent [34] 54.6%(ANSMe). Scheideman observed that the main source of difference is because of the manner in which the lower facial height was expressed (ANSMe vs. ANSGn). Further, the ratio between NANS/ANSMe was found to be 0.80 and 0.81 for males and females, respectively. In terms of facial proportion index (FPI), the values were 11% and 10% for males and females. This finding agreed with that of Opdebeeck et al. [35] Jarabak and Fizzell [36] reported a percentage relationship between anterior and posterior facial height 62%65% to indicate horizontal and vertical growth patterns. Wylie [38] devised a method of rapid evaluation of vertical facial dysplasia. They devised transparencies for the evaluation of profile roentgenograms without actually measuring the films. In the group with good facial pattern, the upper facial height (nasionanterior nasal spine) is 45% and lower facial height (anterior nasal spinementon) is 55% of the total facial height (nasionmenton). Wylie and Johnson [39] conducted a cephalometric evaluation of facial dysplasia in the vertical plane. He reported the mean values for upper facial height (50.65 ± 0.38 mm), total facial height (113.02 ± 0.6 mm) and ratio of upper facial height as a percentage of total facial height (43.84 ± 0.32). He was of the opinion that though these proportions do make a wellbalanced face, one of the measurements may vary from mean without causing a major imbalance if the appropriate compensating area adjusts itself to the required degree. He was one of the first to consider malocclusion or dysplasia as a random combination of craniofacial parts which are by themselves neither large nor small but when taken together produce an undesirable combination of parts. Schwarz [7] noted a ratio of 4:3 or 3:2 for anterior to posterior jaw height for males and females, respectively. He also reported that the ratio of average length of ramus to the length of corpus is 5:7. Broadbent [34] evolved an analysis to measure vertical facial and dentoalveolar heights to assess vertical abnormalities based on the data derived from lateral cephalogram of children comprising of Bolton's standards. SN plane was used as reference plane to describe three sets of measurements and for desired proportional relationships. The ATFH was measured from N to Me perpendicular to SN plane. This was divided into AUFH (AUFHN to ANS) and ALFH (ALFHANS to Me), measured at right angles to SN plane. It was in a ratio of 45:55. Similarly, the posterior total facial height (SN to Go was divided into PUFH and PLFH). PUFH was measured at right angles to SN as far as PNS. The PLFH was measured at right angles to SN as far as gonion. The dentoalveolar vertical segments were divided into anterior and posterior upper and lower dental components. The mean values (in mm) of various vertical measurements are used as a comparison to evaluate vertical disproportions. Opdebeeck et al., [35] introduced the FPI to express the proportions of AUFH to total facial height and ALFH to total facial height (ATFH). FPI is calculated by subtracting AUFH expressed as a percentage of TFH from ALFH expressed as percentage of TFH. In a balanced face, the FPI value is 10 regardless of absolute measurements. The FPI is less than 10 in short faces and more than 10 in long faces. Ricketts [40] conducted studies to establish the relative proportion of facial components and dentition. Measurements of facial photographs, frontal and lateral cephalograms, and plaster models of teeth of subjects with normal occlusion were made. He noted that the various anatomical relationships in the face, skull, and dentition were related by a mathematical ratio of 1:1.618. Di Paolo et al., [8],[9],[10],[11] formulated the quadrilateral analysis to provide an individualized skeletal, dental, and soft tissue assessment of patients requiring treatment especially orthognathic surgery. He found that a ratio of 1:1 exists between maxillary base length and mandibular length. Further, the average of anterior and posterior lower facial height was also found to be equal to the maxillary and mandibular bony base length. Lundstrom and Cooke [41] evaluated lateral cephalograms of 172 adult patients for eight horizontal and two vertical namely upper to lower facial heights and upper to lower jaw heights and one vertical and horizontal proportion (facial height to depth). Lundstrom et al., [42] in another lateral cephalometric study analyzed three facial indices namely facial depth to facial height, lower facial height to total facial height, and horizontal lower and upper apical base relationships. Correlation between facial depth to height index and mandibular plane was found to be highly significant. Facial depth to height and lower facial height relationships were also found to be strongly correlated at each age between 10 and 16 years. The index between maxilla and mandible increased continually between 10 and 16 years in boys and 1014 years in girls by about 0.3 units per year. Most of the values in previous studies are presented in percentages, whereas in the present study it is expressed as ratio. The earlier analyses [30],[43],[44],[45],[46],[47],[48] done based on the analysis of intrinsic facial form and balance does not measure vertical facial heights although dimensional balance between the vertical anatomic segments have shown results similar to the present study. Evaluation of vertical facial proportion is of utmost importance in the comprehensive analysis of a patient. This is very true if the patient has a skeletal discrepancy in the vertical plane. The present analysis measures the relationship between the facial heights anteriorly and posteriorly and the relation between facial height and depth and enables the clinician to perform a thorough evaluation of the face in the vertical direction. Conclusion Thus, the anterior maxilla, posterior maxilla, and cranial floorramus vertical composite are in dimensional balance in subjects with normal occlusion and facial harmony. The ratios established for the various vertical facial height measurements can be used as a guide to localize any vertical skeletal contribution to malocclusion. This analysis helps to identify skeletal deviations in size and position in the vertical dimension and allows the clinician to outline the appropriate orthodontic procedures as deemed necessary. This analysis along with evaluation of sagittal relation and cranial base inclination can be used to determine a comprehensive treatment plan for different type of malocclusions. References


