Noor F

J Bagh College Dentistry

Vol. 24(1), 2012

Palatal dimensions in

Palatal dimensions in different occlusal relationships Mohammed Nahidh, B.D.S., M.Sc. (1) Noor F. K. Al-Khawaja, B.D.S., M.Sc. (2) Ata'a Ghazi, B.D.S., M.Sc. (3)

ABSTRACT Background: This study aimed to compare the palatal dimensions in different occlusal relationships and to find out the genders difference in each relationship. Materials and methods: The sample consisted of 60 sets of dental casts for 60 dental students and patients attending the Orthodontic Department in the College of Dentistry, University of Baghdad. These casts divided into three groups according to the Angle's classification: Class I group: included casts of subjects had Class I normal occlusion and consisted of 10 males and 10 females. Class II Division 1 group: included casts of subjects had Class II Division 1 malocclusion and consisted of 10 males and 10 females. Class III group: included casts of subjects with Class III malocclusion and consisted of 10 males and 10 females. The palatal dimensions were measured using digital vernier and palatometer. Descriptive statistics were performed to each gender and to both genders in each class. Inferential statistics included independent sample t-test to find out the presence of genders difference and ANOVA then LSD tests to show the classes differences in each gender and in the total sample. Results and Conclusions: The results showed that Class I and II males had the largest palatal dimensions than females while Class III females had the largest palatal dimensions than males. Class I subjects had the largest palatal width and depth while Class II subjects had the largest palatal length. Class I males and Class III females had the largest palatal width than other classes. Class III females and Class II males had the largest palatal depth than other classes. Key words: palatal dimension, occlusal relationships. (J Bagh Coll Dentistry 2012;24(1):116-120).

INTRODUCTION The palate, due to its morphology and position, is one of the key anatomical structures in determining the type of skeletal pattern (1) and, most importantly, the palate can be influenced by orthodontic treatment procedures (2). Many studies have been done to compare the palatal dimensions between Class I and Class II malocclusion (3-5), normal occlusion and different malocclusion (6), normal subjects and subjects with Turner's syndrome (7), normal subjects and subjects with Down's syndrome (8,9), thalassemic patients and normal subjects (10), monozygotic and dizygotic twins (11,12) and subjects with open bite, deep bite and normal occlusion (13). On the other hand, two studied were conducted to established the palatal index and compare it in primary, mixed and permanent dentitions (14,15). As a part of the study of dental arch dimensions in Class I occlusion, the palatal dimensions were established and genders differences were found out in many studies (16-19). Other authors tried to find out the relation between the width, depth and circumference of the dental arch in normal occlusion (20,21), while the study of Al-Mulla and Al-Bashir (22) was the specific Iraqi study that investigated the palatal dimensions. (1) Lecturer. Department of Orthodontics, College of Dentistry, University of Baghdad. (2) Assistant Lecturer. Department of Orthodontics, College of Dentistry, University of Baghdad (3) Assistant Lecturer. Department of POP, College of Dentistry, University of Al-Mustansiria.

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This study aimed to compare the palatal dimensions in different occlusal relationships and to find out the genders difference in each relationship.

MATERIALS AND METHODS Sample The sample included 60 sets of dental casts for 60 Iraqi Arab subjects selected from the students and patients of College of Dentistry, University of Baghdad. Sample criteria 1. All subjects had complete permanent dentition regardless the third molars. 2. The age ranged between 18-28 years. 3. No attrition or abrasion in all teeth. 4. Healthy gingival tissue with no gingivitis or periodontitis or any gum recession. 5. Mild or no crowding or spacing in all dental classes. 6. No rotation in all of the teeth. 7. Intact tooth structure, no fracture, caries, trauma or heavy restoration. 8. No history of significant medical disease or trauma. 9. No previous orthodontic, prosthetic or surgical treatment was recorded. The sample was divided into 3 groups according to the Angle's classification (23,24): 1. Class I group: included casts of subjects had Class I normal occlusion and consisted of 10 males and 10 females.


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2. Class II Division 1 group: included casts of subjects had Class II Division 1 malocclusion and consisted of 10 males and 10 females. 3. Class III group: included casts of subjects with Class III malocclusion and consisted of 10 males and 10 females. Equipment 1. Dental mirrors. 2. Dental probes. 3. Kidney dish. 4. Antiseptic solution (Dettol). 5. Cotton. 6. Perforated plastic trays. 7. Rubber bowel 8. Wide bladed plastic spatula. 9. Measurement scoop for mixing alginate and stone. 10. Irreversible hydrocolloid impression material (Alginmax, Italy). 11. Dental stone (Elite Model thixotropic, Italy). 12. Plaster of Paris (Iraq). 13. Rubber mold base. 14. Dial wheel Trimmer (Aurum 7530 Pforzheim, w no. 804953). 15. Sharp lead pencil. 16. Rulers. 17. Digital vernier (Serial No.: 7156682; sensitivity: 0.01 mm. Mitutoyo Digimatic, Japan). 18. Dental vernier (Serial No.:042-751-00; sensitivity: 0.1 mm. Dentaurum, Germany). 19. Palatometer (Siber Hegner and Co. Ag, Zürich. It permits reading to the nearest 0.1 mm.). Methods History and clinical examination Each subject was asked to seat comfortably on the dental chair and asked information about the name, age, origin, medical history, the history of facial trauma and orthodontic treatment. Then they were asked to look forward horizontally (Frankfort plane parallel to the floor) for clinical examination (extra-orally and intra-orally) to check their fulfillment of the required sample selection. All the subjects were classified according to the Angle's classification (23,24) as follows: Class I. It is malocclusion in which the lower first permanent molar is within one half-cusp width of its correct relationship to the upper first permanent molar. This arch relationship is sometimes known as "neutro-occlusion'. Class II Division 1: The lower arch is at least one-half cusp width posterior to the correct relationship with the upper arch judged by the first molar relationship. This arch relationship is Orthodontics, Pedodontics, and Preventive Dentistry117


sometimes known as 'disto-occlusion". The upper central incisors are proclined or of average inclination with an increase in the overjet. Class III: The lower arch is at least one-half cusp width too far forward in relation to the upper arch, judged by the first permanent molar relationship. This arch relationship is sometimes known as 'mesio-occlusion'. Overjet was measured as the distance parallel to the occlusal plane from the incisal edge of the most labial maxillary central incisor to the labial surface of the opposing mandibular central incisor with the use of vernier (25). Overjet was measured to the nearest millimeter (26) and in case of asymmetry, the larger overjet measurement be recorded (27). Dental Cast Production Impressions were taken for every subject with Alginate impression material then poured with a prepared amount of stone. After setting of the dental stone, a base of Plaster of Paris was prepared, and then the poured cast was inverted over it. After the final setting of the gypsum, the base was trimmed uniformly by trimmer and made ready for the measuring procedure. Measurement of the Palatal Dimensions The palatal dimensions were measured according to Riquelme and Green's (11) method as shown in figure 1. 1. Width of the Palate: It was measured with digital vernier as the minimum distance between points A and B of the upper first permanent molars at the cervical aspect of the mesio-palatal cusps at the junction of the tooth and gingival margins. 2. Length of the Palate: It was measured with digital vernier from an anterior point C, defined as the intersection of the mid-sagittal plane with a line passing over the widest point of the incisive papilla, to a posterior point D defined as the intersection of the mid-sagittal plane with a plane passing through the most distal points of the upper first permanent molars. This point can be determined by placing one ruler parallel with a plane passing through the most distal points of the upper first permanent molars and the other perpendicular to it touching the palate (6). 3. Height (Depth) of the Palate: It was measured from a level coinciding with that of points A and B of the maxillary first permanent molars to the highest point of the palatal vault in the midline using the palatometer.


Vol. 24(1), 2012

Statistical Analyses All the data of the sample were subjected to computerized statistical analysis using SPSS version 15 (2006) computer program. The statistical analysis included: 1. Descriptive Statistics a) Means. b) Standard deviations (S.D.). c) Statistical tables. 2. Inferential Statistics a) Independent- samples t-test for the comparison between both genders. b) ANOVA then LSD tests were used to determine the presence of significant differences between the classes. In the statistical evaluation, the following levels of significance are used: Non-significant Significant Highly significant Very highly significant

NS * ** ***

P > 0.05 0.05 ≥ P > 0.01 0.01 ≥ P > 0.001 P ≤ 0.001

Figure 1: Landmarks

RESULTS AND DISCUSSION In Iraq, many studies had been conducted to determine the palatal measurements mostly in Class I occlusion. There is no data regarding Class II and III; so this study was carried out to compare the palatal dimensions in different occlusal relationships. Generally, the present results are difficult to be compared with other studies either due to the difference in the age, the methods of measurements or Class II and III are not included. The palatal dimensions are discussed under three headings: 1. Palatal Width Descriptive statistics and gender difference The results indicated that in Class I, the males had larger palatal width with a very high significant gender difference; this comes in agreement with Al-Zubair (16) and disagrees with Al-Mulla and Al-Bashir (22) who reported a nonsignificant genders difference. In Class II, the Orthodontics, Pedodontics, and Preventive Dentistry118


palatal width of males was larger than females with a non-significant gender difference and just the reverse in Class III where there was slightly larger palatal width in females with a nonsignificant. This variation may be attributed to the cause of Class II or III and the dentoalveolar compensation that mask the skeletal discrepancies. Descriptive statistics and class difference The results showed that the palatal width of males of Class I was larger than other classes followed by Class II then Class III with a significant difference as shown by ANOVA test. LSD test indicated that there was a significant difference between Class I and III only. On the other hand, the palatal width of females of Class III was the largest followed by Class II then Class I with a non- significant difference. For the total sample, Class I showed the largest palatal width followed by Class II and III with a non-significant difference. Angle (23) stated that, Class II Division 1 malocclusion is characterized by a narrowing of the upper arch, abnormal function of the lips, and some form of nasal obstruction and mouth breathing. This confirmed the present results for males and total sample. In females, the palatal width is slightly larger in Class II than Class I; this may be explained by the variability of the size of the maxilla as the cause of Class II are maxillary excess, mandibular deficiency or both. Jones and Oliver (24) stated that, in Class III, in many, but not all, cases the maxillary base is narrow and the mandibular base is wide. The resulting transverse discrepancy is aggravated by the forward position of the mandible relative to the maxilla. As in the case of the dental arches, the skeletal bases diverge posteriorly so that when the lower base is in a forward position, a wider part lies below a given part of the maxilla. In many cases, a buccal inclination of the upper teeth and a lingual inclination of the lower teeth compensate for the transverse discrepancy. However, if this is not sufficient there will be a crossbite. This may explain the increased in the palatal width in Class III females. 2. Palatal Height Descriptive statistics and gender difference In general, the palatal depth or height was larger in males than females in Class I and II and the reverse in Class III with a non-significant genders difference. For Class I occlusion, Al-Zubair (16) reported that the palatal depth was higher significantly in


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males, while Al-Mulla and Al-Bashir (22) found a non-significant genders difference. Descriptive statistics and class difference The results indicated that the palatal depth was larger in Class II males followed by Class I then Class III with a non-significant difference. On the other hand, Class III females showed larger palatal depth followed by Class I then Class II. For the total sample, Class I showed the largest palatal depth followed by Class II and Class III with a non-significant difference. Singh (28) stated that subjects with Class II Division 1 had deep palatal vault but may be average and this causes the variability in Class II Division 1 females. 3. Palatal Length Descriptive statistics and gender difference The results indicated that in Class I and II, the males had larger palatal length with a nonsignificant gender difference, while in Class III; the females showed larger palatal length also with a non-significant gender difference; this may attributed to the increased in the overjet of the males in Class II and the reverse in Class III (table 2). Descriptive statistics and class difference The results showed that the palatal length of males and the total sample of Class II were larger than other classes followed by Class I then Class III with a very high significant difference as indicated by ANOVA test. LSD test showed that there was significant difference between Class I and III and very high significant difference between Class II and III. Regarding the females, Class II showed the largest palatal length followed by Class I then III with a nonsignificant difference. Angle (23) stated that Class II Division 1 malocclusion is characterized by lengthened and protruding upper incisors, abnormal function of the lips, and some form of nasal obstruction and mouth breathing. In the present study, the increase in the palatal length may be attributed to the increased overjet in Class II subjects as point C located behind the upper incisors (table 2). In reverse, Class III subjects had the least palatal length either due to the backward position of the upper incisors relative to the lower or due to maxillary deficiency.

REFERENCES 1. Sassouni V. Position of the maxillary first permanent molar in the cephalofacial complex: A study in three dimensions. Am J Orthod 1957; 43(7): 477-510.



2. Haas AJ. The treatment of maxillary deficiency by opening the midpalatal suture. Angle Orthod 1965; 35(3): 200-17. (IVSL) 3. Papageorgiou IS, Papadopoulos MA, Zafiriadis A. Dentoalveolar characteristics in Class II, division 2 malocclusion. Hellenic Orthod Rev 1998; 1(2):117-34. 4. Papageorgiou IS, Papadopoulos MA. Dentoalveolar characteristics in Class II, division 1 malocclusion. Hellenic Orthod Rev 2002; 5(2):69-82. (IVSL) 5. Staab AE. The relative form of the palate in Class I and Class II malocclusions. J Dent Res 1961; 40(6): 1242-7. (IVSL) 6. Zarringhalam M. Measuring palatal height in normal occlusion and malocclusions. J Dent, Tehran University Medic Sci 2004; 1(4): 39-42. 7. Johnson R, Baghdady VS. Maximum palatal height in patients with Turner’s syndrome. J Dent Res 1969; 48(3): 473-6. (IVSL) 8. Westerman GH, Johnson R, Cohen MM. Variations of palatal dimensions in patients with Down’s syndrome. J Dent Res 1975; 54(4): 767-71. (IVSL) 9. Ghaib NH. Maxillary arch dimensions and palatal dimensions in Down’s syndrome (trisomy 21). J Coll Dentistry 2003; 15: 22-6. 10. Muhi Eldeen AAM. Dental arch dimensions in a sample of Iraqi Thalassemic patients aged 12-16 years with Class I normal occlusion. A master thesis, Department of Orthodontics, University of Baghdad, 2004. 11. Riquelme A, Green LJ. Palatal width, height, and length in human twins. Angle Orthod 1970; 40(2): 719. (IVSL) 12. Al-Baghdady SHA. The role of environmental versus genetic factors on tooth and dental arch dimensions in a twin sample. A master thesis, Department of Orthodontics, University of Baghdad, 2007. 13. Abdulmawjood AA, Ahmed MK, Al-Saleem NR. Palatal depth and arch parameter in Class I open bite, deep bite and normal occlusion. Iraqi Orthod J 2005; 1(2): 26-31. 14. Howell S. Assessment of palatal height in children. Community Dent Oral Epidemiol 1981; 9(1): 44-7. 15. Younes S, El-Angbawi MF, Al-Dosari AM. A comparative study of palatal height in a Saudi and Egyptian population. J Oral Rehabil 1995; 22(5): 3915. 16. Al-Zubair NMM. Maxillary and mandibular dental arch dimensions and forms in a sample of Yemeni population aged (18-26) years with Class I normal occlusion. A master thesis, Department of Pedodontics, Orthodontics and Preventive Dentistry, University of Baghdad, 2002. 17. Al-Kodimi NH. Dental arch dimensions in Yemeni sample aged 10-15 years with normal occlusion and Class I with anterior crowding in both arches: comparative study. A master thesis, Department of Pedodontics, Orthodontics and Preventive Dentistry, University of Baghdad, 2003. 18. Al-Hadithy SF. Dental arch dimensions and forms in Sulaimania Kurdish population sample aged 16-24 years with Class I normal occlusion. A master thesis, Department of Orthodontics, University of Baghdad, 2005. 19. Karim FA. Dental arch perimeter and dimensions during mixed dentition period (8 – 10 years) in Sulaimani governorate (cross – sectional study). A master thesis, Department of Pedodontics,


20.

21.

22.

23.

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Orthodontics and Preventive Dentistry, University of Sulaimani, 2006. Eid AA, Nammrawy MM, Kadry WA. The relationship between the width, depth and circumference of dental arch for group of Egyptian school children. Egypt J Orthod 1987; 1(2): 113-37. Salman KA. The relationship between the maxillary dental arch width, depth and circumference. Al– Rafidain Dent J 2001; 1 (Special Issue): 401-10. Al-Mulla A, Al-Bashir A. A new method for determination of highest point of the palate and its correlation. Iraqi Dent J 1997; 19: 71-82. Angle EH. Classification of malocclusion. Dent Cosmos 1899; 41(3): 248-64.


24. Jones ML, Oliver RG. W&H Orthodontic Notes. 6th ed. Oxford: Wright; 2000. p. 59-60, 117. 25. Little RM, Riedel RA. Post-retention evaluation of stability and relapse– mandibular arches with generalized spacing. Am J Orthod Dentofac Orthop 1989; 95(1): 37-41. 26. Draker HL. Handicapping labio-lingual deviations: a proposed index for public health purposes. Am J Orthod 1960; 46(4): 295- 305. 27. Haynes S. The distribution of overjet and overbite in English children aged 11-12 years. Dent Practit 1972; 22(10): 380-3. 28. Singh G. Textbook of Orthodontics. 2nd ed. New Delhi: Jaypee Brothers medical publishers (P) Ltd.; 2007. p. 623.

Length (mm.)

Height (mm.)

Width (mm.)

Variable s

Table 1: Descriptive statistics, genders differences and classes' differences Sex Males Females Total t-test d.f p-value Males Females Total t-test d.f p-value Males Females Total t-test d.f p-value

Descriptive statistics Class I Class II Div.1 Class III Mean S.D. Mean S.D. Mean S.D. 37.46 2.91 35.14 3.09 33.42 3.43 32.66 2.12 33.61 1.95 34.5 1.97 35.06 3.51 34.37 2.63 33.96 2.77 4.18 1.32 -0.82 18 18 18 0.001 *** 0.2 (NS) 0.43 (NS) 15 1.43 15.65 2.79 14.5 1.17 14.8 2.15 14 1.29 14.94 2.19 14.9 1.78 14.83 2.28 14.72 1.72 0.25 1.69 -0.54 18 18 18 0.81 (NS) 0.11 (NS) 0.59 (NS) 29.09 1.79 30.61 2.06 26.76 2.22 28.85 1.37 29.53 1.28 27.81 1.79 28.97 1.55 30.07 1.76 27.29 2.03 0.35 1.42 -1.11 18 18 18 0.73 (NS) 0.17 (NS) 0.28 (NS)

Classes' differences ANOVA test LSD test F-test p-value I-II I-III II-III 3.97 0.03 * (NS) * (NS) 1.94 0.16 (NS) (NS) (NS) (NS) 0.65 0.52 (NS) (NS) (NS) (NS) d.f. (male)=29 d.f. (female)=29 d.f. (total)=59 0.83 0.45 (NS) (NS) (NS) (NS) 0.69 0.51 (NS) (NS) (NS) (NS) 0.04 0.96 (NS) (NS) (NS) (NS) d.f. (male)=29 d.f. (female)=29 d.f. (total)=59 8.68 0.001 *** (NS) * *** 3.21 0.06 (NS) (NS) (NS) (NS) 11.68 0.000 *** (NS) * *** d.f. (male)=29 d.f. (female)=29 d.f. (total)=59

Table 2: Descriptive statistics of the overjet in both sexes and in different occlusal relations Variable

Sex

Overjet (mm.)

Males Females

Class I Mean S.D. 2 0.5 2 0.9


Class II Div. 1 Mean S.D. 5.7 2.6 5.1 1.8

Class III Mean S.D. -1.92 1.39 -1.62 1.85