Hasan.doc J Bagh College Dentistry Vol. 27(1), March 2015 Evaluation of the Pedodontics, Orthodontics and Preventive Dentistry 164 Evaluation of the relationship between curve of Spee and dentofacial morphology in different skeletal patterns Hasan Jameel Kazem Al-Amiri, B.D.S. (1) Dhiaa Jaafar N. Al-Dabagh, B.D.S., M.Sc. (2) ABSTRACT Background: Curve of Spee (CS) is an anteroposterior anatomical curve established by the occlusal alignment of the teeth viewed in the sagittal plane. This occlusal curvature has clinical importance in orthodontics and other fields of dentistry. This study aimed to evaluate the relationship between the CS and dentofacial morphology of different skeletal patterns in both genders. Materials and Methods: Eighty six Iraqi Arab subjects (44females,42 males ) their age ranged from 17 -30 years, classified into: Skeletal I with normal occlusion(15 females and 15 males), skeletal II with CI II div 1 malocclusion (15 females and 15 males) and skeletal III with CI III malocclusion (14 females and 12 males). Forty one variables measured using direct dental cast measurements , dental cast photographs and cephalometric radiographs with the aid of AutoCAD program version 15 (2006). Results: No significant differences in the CS depth between males and females or between right and left sides in both arches of different skeletal patterns. No significant differences in the maxillary CS among the 3 skeletal patterns, the mandibular CS in CI II div 1 malocclusion was larger than normal occlusion and CI III malocclusion. Maxillary CS significantly correlated to arch length, inter canine distance and inter second premolar distance in normal occlusion and overbite in Cl III malocclusion. Mandibular CS significantly correlated with overbite and overjet in Cl II div 1 and Cl III malocclusions. Conclusions: CS was not influence by sides and gender in both arches of different skeletal patterns. CS was concave in the mandibular arch with the maximum concavity at the mesio-buccal cusp tip of the mandibular first molar and convex in the maxillary arch with the maximum convexity at the buccal cusp tip of the maxillary second premolar, in different skeletal patterns. Key words: Curve of Spee, arch length, overbite, overjet, dentofacial morphology. (J Bagh Coll Dentistry 2015; 27(1):164-168). INTRODUCTION The curve of Spee was described firstly in 1890 by F. Graf von Spee, a German anatomist (1855-1937), who used skulls with abraded teeth to define the line of occlusion as the line on a cylinder tangent to the anterior border of the condyle, the occlusal surface of the second molar, and the incisal edges of the mandibular incisors(1). Spee located the center of this cylinder in the midorbital plane so that it had a radius of 6.5 to 7.0 cm.(2).The curve of Spee depth is minimal in the deciduous dentition, it increases to maximum depth with eruption of the permanent second molars and then remained relatively stable into late adolescence and early adulthood (3). The functional significance of the curve of Spee depth has not been completely understood (4). However, it had been suggested that it had a biomechanical function during food processing by increasing the crush-shear ratio between the posterior teeth and the efficiency of occlusal forces during mastication (5). An increased curve of Spee was seen in brachycephalic facial patterns (6) and associated with short mandibular bodies (7). The curve of Spee was influenced by the ratio between posterior and anterior facial heights (4). (1) Master Student. Department of Orthodontics, College of Dentistry, University of Baghdad (2) Assistant Professor, Department of Orthodontics, College of Dentistry, University of Baghdad Certain cephalometric and dental factors were associated with individual variations in the curve of Spee (8). Little information's were found regarding the curve of Spee in different skeletal patterns in Iraqis, specially by using computerized method of assessment, so it is intended to implement this study to establish a baseline data regarding: 1. The features of the curve of Spee in different skeletal patterns in Iraqis. 2. Gender difference of the curve of Spee in different skeletal patterns. 3. The relations between the curve of Spee and dentofacial morphology. MATERIALS AND METHODS Fifty females and forty six males of Iraqi Arab subjects with an age range between 17 - 30 years and full permanent teeth excluding the third molars were selected from College of Dentistry, Baghdad University after clinically examining 312 subjects (152 females, 160 males) because of the following exclusion criteria: cast restoration or cuspal coverage, TMJ disorder (9), severe craniofacial disorders (10), previous orthodontic, orthopedic or facial surgical treatments(11), active periodontal diseases (1),supernumerary tooth or teeth, transposition of teeth, microdontia and/or macrodontia and history of systemic diseases. J Bagh College Dentistry Vol. 27(1), March 2015 Evaluation of the Pedodontics, Orthodontics and Preventive Dentistry 165 The following records were taken for every subject included in this study: 1- Dental casts (86 pairs of dental casts). 2- Three photographs for every dental cast (occlusal, left side and right side for upper and lower dental cast photographs). 3- Eighty six digital lateral cephalometric radiographs. The sample sub divided into:-Skeletal I with normal occlusion, skeletal II with Cl II div 1 malocclusion and skeletal III with Cl III malocclusion. Each subject was clinically examined (intraorally and extraorally) to check his/her fulfillment of the required criteria. Impression of the dental arches was taken before taking lateral cephalometric radiograph. Each dental cast would be numbered on the artistic portion on the left side, right side and occlusal view to be ready for photograph. Then cephalometric radiograph was taken under rigidly standardized conditions using DIMAX3 digital x-ray unit system machine. The standardization of the dental casts photographs that was used in this study was similar to the standardization method used by Saadi (13). Once the picture of the photographs and radiographs imported to the AutoCAD program, it would be divided by scale for each picture to overcome the magnification. Linear and angular measurements would be obtained by using the AutoCAD measuring tools, on the lateral view the occlusal plane was determined, then perpendicular distances from the occlusal plane to the buccal cusp tip of each lateral tooth were measured. CS of the particular dental arch was determined by taking the average of the points located at the maximum concavity in the lower arch (below occlusal plane) with its contralateral tooth and the points located at the maximum convexity in the upper arch (above occlusal plane) with its contralateral tooth, while on the occlusal view Inter canine distance (ICD), Inter second premolar distance (ISPD), Inter first molar distance (IFMD), Inter second molar distance (ISMD) and Arch length (AL) were measured. The overbite and overjet were directly measured on the study cast using dental vernier (14). Cephalometric skeletal and dental measurements used in this study were Frankfort Mandibular plane Angle, ANB angle, Gonial angle, Inter incisal angle, incisor mandibular plane angle, Lower anterior facial height and Posterior facial height. Data of the sample were subjected to computerized statistical analysis using SPSS version 15 (2006) computer program. Descriptive Statistics included mean values and standard deviations. Inferential Statistics included Paired t- test, Independent- samples t-test, Analysis of variance (ANOVA) test, least significant difference (LSD test) and Pearson’s correlation coefficient (r) were done. RESULTS Table1 showed the descriptive statistics (means and standard deviations) and side differences for the depth of each lateral tooth relative to occlusal plane in Cl I, Cl II and Cl III respectively. Statistically no significant side difference was found in both arches. Table1: Depth of each lateral tooth relative to occlusal plane Teeth No. Side (d. f. = 28) CI I CI II (d. f. = 28) CI III (d. f. = 24) Descriptive Statistics Side difference Descriptive Statistics Side difference Descriptive Statistics Side difference Mean S.D. t-test p-value Mean S.D. t-test p-value Mean S.D. t-test p-value Upper 2 L -0.02 0.61 0.22 0.824 (NS) 0.53 0.94 0.32 0.748 (NS) 0.09 1.10 -1.51 0.143 (NS) R -0.04 0.66 0.46 1.48 0.43 0.91 Upper 3 L 1.34 0.89 0.46 0.650 (NS) 2.01 1.62 1.71 0.097 (NS) 1.17 1.54 1.67 0.108 (NS) R 1.28 0.89 1.70 2.04 0.43 2.05 Upper 4 L 2.08 0.96 0.97 0.340 (NS) 2.52 1.30 1.70 0.100 (NS) 2.18 0.92 0.91 0.370 (NS) R 1.94 1.14 2.30 1.35 1.98 1.40 Upper 5 L 2.13 0.93 1.04 0.305 (NS) 2.64 1.35 1.42 0.165 (NS) 2.33 1.02 -0.03 0.973 (NS) R 1.96 1.10 2.37 1.22 2.32 1.34 Upper 6 L 1.69 0.80 0.39 0.6991 (NS) 2.05 1.28 1.12 0.270 (NS) 1.94 0.89 0.93 0.363 (NS) R 1.63 0.86 1.86 1.07 1.75 1.18 Lower 2 L 0.51 0.36 0.64 0.527 (NS) 0.28 0.62 -1.00 0.324 (NS) 0.33 0.70 -1.02 0.319 (NS) R 0.45 0.51 0.40 0.68 0.45 0.59 Lower 3 L 0.66 0.70 -0.83 0.416 (NS) 0.40 1.12 -0.78 0.440 (NS) 0.73 0.92 -1.00 0.327 (NS) R 0.77 0.81 0.50 1.22 0.91 0.96 Lower 4 L -0.43 0.79 -1.31 0.201 (NS) -0.78 1.41 -1.44 0.160 (NS) -0.09 1.31 -1.46 0.156 (NS) R -0.25 0.83 -0.56 1.55 0.20 1.07 Lower 5 L -1.03 0.96 -0.78 0.441 (NS) -1.50 1.19 -1.24 0.224 (NS) -0.79 1.20 -1.17 0.254 (NS) R -0.94 1.06 -1.25 1.62 -0.52 1.19 Lower 6 L -1.57 0.83 -0.54 0.596 (NS) -1.76 1.02 -1.61 0.119 (NS) -1.08 1.05 -1.93 0.065 (NS) R -1.50 1.09 -1.57 1.30 -0.73 0.88 All measurements are in millimeters, L: Left side, R: Right side, t-test: Paired t-test, NS: None significant p-value > 0.05. J Bagh College Dentistry Vol. 27(1), March 2015 Evaluation of the Pedodontics, Orthodontics and Preventive Dentistry 166 Table 2 showed the descriptive statistics and gender difference of the CS in Cl I, Cl II and Cl III respectively, however (t-test and p-value) showed no significant gender differences in both arches in all 3 classes. Table 2: Gender difference of the mean depth of contra-lateral teeth relative to occlusal plane. Teeth Gender Females 15 males d.f.=28 15 CI I CI II 15 Females 15 males d.f.=28 CI III 14 Females 12 males d.f.=24 Mean S.D. t-test p-value Mean S.D. t-test p-value Mean S.D. t-test p-value Upper 2 Males 0.01 0.66 0.580 0.564 (NS) 0.53 1.14 0.551 0.584 (NS) 0 1.24 -1.765 0.084 (NS) Females -0.08 0.61 0.35 1.37 0.48 0.72 Upper 3 Males 1.46 0.81 1.270 0.209 (NS) 2.33 1.67 1.595 0.116 (NS) 0.94 1.75 0.483 0.631 (NS) Females 1.17 0.94 1.66 1.62 0.69 1.93 Upper 4 Males 2.06 0.99 0.412 0.682 (NS) 2.33 1.61 0.112 0.912 (NS) 1.85 1.03 -1.295 0.201 (NS) Females 1.95 1.12 2.29 1.09 2.27 1.27 Upper 5 Males 2.01 0.98 -0.256 0.799 (NS) 2.23 1.42 -1.655 0.103 (NS) 2.24 1.01 -1.663 0.103 (NS) Females 2.08 1.06 2.78 1.09 2.71 1.01 Upper 6 Males 1.62 0.82 -0.403 0.688 (NS) 1.91 1.26 -0.278 0.782 (NS) 1.74 0.73 -1.6 0.116 (NS) Females 1.70 0.85 2.00 1.10 2.16 1.10 Lower 2 Males 0.58 0.39 1.740 0.087 (NS) 0.18 0.73 -1.978 0.053 (NS) 0.46 0.41 0.649 0.519 (NS) Females 0.38 0.47 0.50 0.51 0.36 0.71 Lower 3 Males 0.79 0.71 1.720 0.091 (NS) 0.17 1.51 -1.492 0.141 (NS) 0.80 0.92 -0.176 0.861 (NS) Females 0.50 0.65 0.66 0.97 0.84 0.97 Lower 4 Males 0.08 1 1.526 0.132 (NS) -0.89 1.48 -1.898 0.063 (NS) -0.14 1.23 -1.093 0.280 (NS) Females -0.30 0.96 -0.16 1.52 0.22 1.15 Lower 5 Males -0.68 0.95 1.793 0.078 (NS) -1.44 1.36 -0.709 0.481 (NS) -0.84 1.22 -1.042 0.302 (NS) Females -1.15 1.06 -1.18 1.57 -0.50 1.16 Lower 6 Males -0.99 0.97 1.101 0.275 (NS) -1.43 1.22 0.234 0.815 (NS) -1.09 1.18 -1.233 0.223 (NS) Females -1.34 1.44 -1.50 1.33 -0.75 0.76 All measurements are in millimeters, t-test: Independent samples t-test, NS: None significant p-value > 0.05. Table 3 showed the descriptive statistics and classes difference for the maxillary and mandibular CS among the 3 classes. The maxillary CS had larger value than the mandibular CS in all 3 Classes. The mean value of the maxillary CS was largest in CI II div 1 malocclusion and smallest in normal occlusion. While, the mean value of the mandibular CS was largest in CI II div 1 malocclusion and smallest in CI III malocclusion. Table 3: Comparison among classes regarding curve of Spee and depth of the teeth relative to occlusal plane. Arches Classes Descriptive Statistics Classes' differences ANOVA LSD Mean S.D. F-test p-value I-II I-III II-III Maxillary CS I 2.14 0.79 1.857 0.163 (NS) - - - II 2.58 1.22 III 2.57 0.97 Mandibular CS I -1.15 1.27 3.138 0.049 (S) 0.041 (S) 0.815 (NS) 0.028 (S) II -1.80 1.37 III -1.08 0.84 All measurements are in millimeters, CS: Curve of Spee, S: Significant, HS: Highly Significant, NS: None significant. Table 4 showed the Pearson's correlation coefficient factor and p- value among the Maxillary and Mandibular CS with the other measured variables in the 3 skeletal classes. DISCUSSION In this study attempt was made to separate the sample according to gender, skeletal patterns and select a limited range of age to evaluate the variables more precisely. Data obtained in this study showed no significant gender and side differences in the mean of the mandibular CS depth that agreed with the results of Currim and Wadkar (15). No significant gender difference in the maxillary CS depth that agreed with the result of Cheon et al. (9). There was no significant side difference in the maxillary CS depth that disagreed with the result of Cheon et al. (9) possibly due to racial difference or the sample of a right handed subjects. Data showed an upward concave CS relative to occlusal plane in the mandibular arch that was agreed with Garcia (16) and a downward convex CS relative to occlusal plane in the maxillary arch that was agreed with the result of Shannon and Nanda(9). J Bagh College Dentistry Vol. 27(1), March 2015 Evaluation of the Pedodontics, Orthodontics and Preventive Dentistry 167 The present findings showed that, the maximum concavity in the mandibular CS was the mesio-buccal cusp tip of the first molar that was agreed with the results of Ferrario et al. (17) but disagreed with Koyoma (18) who found that the deepest point of the CS in the mandibular arch was in the second premolar. The buccal cusp tip of the maxillary second premolar was the maximum convexity in the maxillary CS, agreed with Cheon et al. (9). The convexity of the maxillary CS was larger relative to occlusal plane than the concavity of the mandibular CS in all 3 classes that was agreed with Cheon et al.(9) but, in contrast to the result of Xu et al. (19) who determined anterior point of the maxillary CS from the tip of the canine. The mandibular curve of Spee in skeletal CI II was significantly deeper when compared with skeletal CI I and skeletal CI III subjects, that was agreed with Shannon and Nanda (8). However, no significant differences in the depth of the CS between skeletal CI I and skeletal CI III. Table 4: Correlations between the curve of Spee and the measured variables Variables Pearson’s correlation coefficient Class I Class II Class III Maxillary CS Mandibular CS Maxillary CS Mandibular CS Maxillary CS Mandibular CS Upper LAL R - 0.461 - 0.325 - 0.317 - 0.278 - 0.267 - 0.213 p-value 0.010 (HS) 0.080 (NS) 0.087 (NS) 0.136 (NS) 0.187 (NS) 0.296 (NS) Upper RAL R - 0.406 - 0.349 - 0.306 -0.351 - 0.360 - 0.047 p-value 0.026 (S) 0.059 (NS) 0.100 (NS) 0.057 (NS) 0.071 (NS) 0.820 (NS) Upper ICD R 0.540 - 0.217 - 0.083 - 0.015 - 0.209 - 0.113 - p-value 0.002 (HS) 0.250 (NS) 0.664 (NS) 0.937 (NS) 0.306 (NS) 0.582 (NS) Upper ISPD R 0.389 - 0.240 - 0.044 - 0.253 - -0.227 0.093 - p-value 0.034 (S) 0.201 (NS) 0.819 (NS) 0.177 (NS) 0.265 (NS) 0.650 (NS) Upper IFMD R 0.353 - 0.130 - 0.168 - 0.086 - 0.325 - 0.102 - p-value 0.056 (NS) 0.493 (NS) 0.375 (NS) 0.651 (NS) 0.105 (NS) 0.621 (NS) Upper ISMD R 0.347 - 0.008 - 0.047 - 0.049 - 0.142 - 0.168 - p-value 0.060 (NS) 0.967 (NS) 0.804 (NS) 0.799 (NS) 0.490 (NS) 0.412 (NS) Lower ICD R 0.203 - 0.224 - 0.132 - 0.015 - 0.079 - 0.416 - p-value 0.282 (NS) 0.235 (NS) 0.488 (NS) 0.939 (NS) 0.702 (NS) 0.035 (S) Lower ISPD R 0.089 - 0.184 - 0.052 - 0.092 - 0.023 - 0.149 - p-value 0.641 (NS) 0.330 (NS) 0.784 (NS) 0.628 (NS) 0.912 (NS) 0.469 (NS) Lower IFMD R 0.235 - -0.145 0.024 - 0.213 - 0.129 - 0.039 - p-value 0.212 (NS) 0.444 (NS) 0.899 (NS) 0.259 (NS) 0.531 (NS) 0.851 (NS) Lower ISMD R 0.253 - 0.059 - 0.012 - 0.066 - 0.239 - 0.097 - p-value 0.177 (NS) 0.757 (NS) 0.949 (NS) 0.730 (NS) 0.239 (NS) 0.639 (NS) Lower LAL R - 0.292 - 0.406 - 0.169 -0.194 -0.316 - 0.175 p-value 0.118 (NS) 0.026 (S) 0.373 (NS) 0.304 (NS) 0.116 (NS) 0.394 (NS) Lower RAL R - 0.302 - 0.342 - 0.253 -0.282 0 - 0.084 p-value 0.105 (NS) 0.064 (NS) 0.178 (NS) 0.130 (NS) 1 (NS) 0.683 (NS) FMA R - 0.085 -0.041 - 0.520 - 0.087 -0.001 -0.174 p-value 0.656 (NS) 0.828 (NS) 0.003 (HS) 0.646 (NS) 0.995 (NS) 0.395 (NS) ANB R 0.186 - 0.139 - 0.204 - 0.268 - 0.231 - 0.203 - p-value 0.326 (NS) 0.464 (NS) 0.279 (NS) 0.152 (NS) 0.256 (NS) 0.320 (NS) GA R - 0.054 - 0.168 - 0.334 - 0.097 - 0.193 - 0.087 p-value 0.775 (NS) 0.375 (NS) 0.072 (NS) 0.609 (NS) 0.344 (NS) 0.673 (NS) IIA R 0.222 0.169 0.337 0.121 0.122 0.093 p-value 0.238 (NS) 0.371 (NS) 0.069 (NS) 0.524 (NS) 0.553 (NS) 0.652 (NS) IMPA R -0.152 -0.075 -0.367 -0.094 - 0.140 - 0.423 p-value 0.422 (NS) 0.695 (NS) 0.046 (S) 0.622 (NS) 0.496 (NS) 0.031 (S) LAFH R - 0.041 0 - 0.196 -0.039 -0.120 -0.012 p-value 0.829 (NS) 0.998 (NS) 0.300 (NS) 0.839 (NS) 0.558 (NS) 0.955 (NS) PFH R 0.320 0.090 0.248 0.065 0.372 0.184 p-value 0.085 (NS) 0.636 (NS) 0.187 (NS) 0.735 (NS) 0.061 (NS) 0.368 (NS) Overbite R 0.046 0.154 0.259 0.673 0.527 0.664 p-value 0.810 (NS) 0.415 (NS) 0.167 (NS) 0.000 (HS) 0.006 (HS) 0.000 (HS) Overjet R 0.263 0.210 0.030 0.565 0.208 0.391 p-value 0.160 (NS) 0.266 (NS) 0.873 (NS) 0.001 (HS) 0.308 (NS) 0.048 (S) LAL: Left arch length, RAL :Right arch length NS: None significant, S: Significant, HS: High significant,(r):Pearson’scorrelation coefficient. No significant differences in the depth of the maxillary CS among the 3 skeletal classes, possibly because of the high variability in incisors positions relation of maxillary and mandibular relationships , that was agreed with Shannon and Nanda(8). Significant correlation was found between FMA and CS depth in skeletal CI II, that came in agreement with Shannon and Nanda (8). The CS had no significant correlation with GA, LAFH and PFH , that agreed with Cheon et J Bagh College Dentistry Vol. 27(1), March 2015 Evaluation of the Pedodontics, Orthodontics and Preventive Dentistry 168 al.(9) but disagreed with Farella et al.(4) who found that the CS was more marked in short-face subjects and less marked in long-face subjects because in this study generally, the sample was of a normal or long face type. There were statistically high significant correlation between CS and overbite and overjet in skeletal CI II and skeletal CI III which agreed with the results of Baydas et al. (10). 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J Prosthet Dent 2004; 92(6):536-9. لخالصةا األسنان تقویم في سریریھ أھمیة لھ اإلطباق في نحناءاال ھذا. السھمي المستوى في ویظھر األسنان إطباق بمحاذاة ینشأ , خلفي أمامي تشریحي منحني ھو سبي منحنى :الخلفیة السني بالتشكل وعالقتھ سبي منحنى تقییم إلى الدراسة ھذه ھدفت . معالجتھ تمی مریض كل في تقریبا سبي منحنى مع یتعاملون األسنان تقویم أطباء .األخرى األسنان طب مجاالتو و األسنان لصور قیاساتو ؛ األسنان إلطباق مباشرة قیاسات باستخدام مختلفة أسالیب في المتغیرات من) 41( قیاس طریق عن الجنسین كال في العظمي الھیكل مختلفة نماطأل ألوجھي .2006 نسخة أوتوكاد امجبرن بمساعدة الرأس أشعة : التالي النحو على تصنف ، سنة 30- 17 بین أعمارھم تراوحت) 44= اإلناث ،42= الذكور( العرب العراقیین من شخص" 86" من الدراسة عینة تكونت :العینة و المواد 15 و إناث 15( األسنان اإلطباق سوء 1 شعبة الثانیة الدرجة مع الثاني الصنف العظمي كلالھی ،) ذكور 15 و إناث 15( الطبیعي األسنان إطباق مع األول الصنف العظمي الھیكل - ) .ذكور 12 و إناث 14( األسنان اإلطباق سوء الثالثة الدرجة مع الثالث الصنف العظمي الھیكل و) ذكور للبیانات اإلحصائي التحلیل باستخدام سبي منحنى كان .المختلفة العظمي الھیكل أنماط من الفكین كال في األیسر و األیمن الجانبین بین أو واإلناث الذكور بین سبي منحنى عمق في إحصائیة داللة ذات فروق توجد ال :النتائج من الشدق أعتاب طرف في بتحد أقصى مع العلوي الفك قوس في محدبةو السفلي لفكل األولى الرحى من شدقي إنسي أعتاب طرف في التقعر أقصى مع السفلي الفك قوس في مقعرة .المختلفة العظمي الھیكل أنماط ،في العلوي لفكل الثاني الضاحك سوء 1 شعبة الثانیة الدرجة في السفلي الفك في سبي منحنى كان ، حین في الثالثة العظمي الھیكل أنماط بین من العلوي لفكل سبي منحنى في إحصائیة داللة ذات فروق توجد ال سوء الثالثة الدرجة و الطبیعي األسنان إطباق بین السفلي الفك في سبي منحنى في كبیر فرق یوجد ال. اإلطباق سوء الثالثة الدرجة و الطبیعي األسنان إطباق من بالمقابلة رأكب اإلطباق . اإلطباق الدرجة في العضة تراكب و الطبیعي، اإلطباق في الثاني الضاحك و النابین بین العرضیة والمسافة العلوي القوس طول معكبیر بشكل مترابط العلوي الفك في سبي منحنى :االستنتاجات سوء 1 شعبة الثانیة الدرجة في ، بینما. الثالث الدرجة اإلطباق سوء و الطبیعي اإلطباق في العضة تراكب معكبیر بشكل مترابط السفلي الفك في سبي منحنى .اإلطباق سوء الثالث . العضة وتراكب بروز األسنان مع سبي منحنى بین كبیر ارتباط ھناك كان اإلطباق