|Year : 2016 | Volume
| Issue : 2 | Page : 81-84
Correlation between inverted maxillary central incisor form and face form in a sample of Sudanese population
Noha Hassan Hussein1, Nadia Khaliaf2, Mohammed Nasser Alhajj3
1 Department of Prosthodontics, Dental Military Hospital, Ministry of Defense, Khartoum, Sudan
2 Department of General and Specialist Dental Practice, College of Dental Medicine, University of Sharjah, Sharjah, UAE
3 Department of Oral Rehabilitation, Faculty of Dentistry, Khartoum University, Khartoum, Sudan; Department of Prosthodontics, Faculty of Dentistry, Thamar University, Dhamar, Yemen
|Date of Web Publication||9-Aug-2016|
Mohammed Nasser Alhajj
Department of Oral Rehabilitation, Faculty of Dentistry, Khartoum University, Khartoum, Sudan
Source of Support: None, Conflict of Interest: None
Introduction: The selection of artificial teeth is an important concern in complete denture construction. Many theories were developed to objectively select artificial teeth, to simplify the process of choice and to make it more suitable.
Objectives: This study was conducted to evaluate the correlation between inverted maxillary central incisors form and face form in a sample of Sudanese population.
Materials and Methods: One hundred and sixty-four dental students (138 females and 26 males), with a mean age (20.8 ± 1.81), were randomly selected. Three horizontal distances of the right maxillary central incisor were measured, (cervical width, contact point width, and incisal width). For facial measurements, three horizontal distances on the face were measured, (bitemporal width, bizygomatic width, and bigonial width).
Results: Chi-square test was used to estimate the association between face form and central incisor form. No association between tooth form and face form was detected in the study sample (P = 0.092).
Conclusion: The findings of our study indicate that this method is not applicable for selection of maxillary anterior teeth in the study sample.
Keywords: Artificial teeth selection, central incisor form, facial form, Sudanese
|How to cite this article:|
Hussein NH, Khaliaf N, Alhajj MN. Correlation between inverted maxillary central incisor form and face form in a sample of Sudanese population. Saudi J Oral Sci 2016;3:81-4
|How to cite this URL:|
Hussein NH, Khaliaf N, Alhajj MN. Correlation between inverted maxillary central incisor form and face form in a sample of Sudanese population. Saudi J Oral Sci [serial online] 2016 [cited 2020 Jun 5];3:81-4. Available from: http://www.saudijos.org/text.asp?2016/3/2/81/188076
| Introduction|| |
Facial appearance has important social and psychological effects on the human personality. The most common features associated with facial attraction are the eyes and mouth. The loss of natural anterior teeth can be shocking for some individuals, thus, replacement with artificial ones is necessary for the restoration of function and esthetics. The importance of esthetics in patient's acceptance of any prosthodontic appliance has been underlined to be one of the most important factors. The selection of artificial teeth is an important concern in complete denture construction. Many theories were developed to objectively select artificial teeth, to simplify the process of choice and to make it more suitable. The William's law of harmony  suggested that “there is harmony between the face and inverted maxillary central incisor shapes,” classifying the face and tooth shape into square, tapered, square-tapered, and ovoid. The William's theory obtained great acceptance and has been used for manufacturing artificial teeth and is currently being considered as a standard. Many attempts have been made to use the facial measurements as a guide for the selection of maxillary anterior teeth for complete dentures. Although the teeth must be in proportion to one another, they must be in proportion to the face. A great variation in the size of the teeth in relation to the face may affect the ability to obtain a good esthetic appearance. Normally, the maxillary central incisor is used as a guide for the selection of the artificial anterior teeth because it is considered as the key tooth of the smile and appearance. Since the maxillary central incisor is the most visible to the casual observer in unstrained facial activity, it makes the best statement of patient age, whereas lateral incisor reflects patient's sex, whereas the canine reflects patient's vigor. This study was conducted to evaluate the correlation between inverted maxillary central incisors form and face form in a sample of Sudanese population.
| Materials and Methods|| |
A total of 164 dental students (138 females and 26 males) with mean age (20.8 ± 1.81) ranged from 17 to 25 years were randomly selected. The sample size was calculated from a previous study. The randomized selection was done using SPSS (IBM, Chicago, USA) by numbering the students, and then using SPSS to select the required numbers randomly. All subjects were Sudanese in origin and attended the Faculty of Dentistry, University of Khartoum. Dental students who possessed complete dental arches with natural maxillary teeth in good alignment were included the study. Factors considered the part of exclusion criteria were restored maxillary anterior teeth by complete or partial veneer crown; extensive carious lesions, incisal wear, tooth fracture, and gingival hyperplasia of the maxillary anterior teeth; previous orthognathic surgery or orthodontic treatment; and congenital or surgical facial defects and any anomalies of the teeth.
Before commencing the study, the aims of the study were explained to the participants and a written consent was obtained. An approval letter from the Ethical Committee of the University of Khartoum (Faculty of Dentistry) was obtained. Three horizontal distances of the right maxillary central incisor were measured: The cervical width, the contact point width, and the incisal width (IW), using digital caliper (Digital Caliper, Hornady, New York, USA). For facial measurements, the participant was seated in an upright position in the dental chair, with the head being parallel to the floor. Three horizontal distances on the face were measured using a bow caliper and millimeter ruler. The distances were the bitemporal width, bizygomatic width, and bigonial width. Bitemporal width was measured from the most lateral point on each side of the forehead. Bizygomatic facial width was measured from the most lateral point of the soft tissue overlying each zygomatic arch. Bigonial width was measured from the soft tissue overlying the most lateral point of each mandibular angle. According to certain parameters, the right inverted maxillary central incisor and the face forms were categorized. Three readings of each measure were taken, and the mean of each measure was calculated. For data analysis, SPSS version 18.0 was used for entering and analyzing. Descriptive statistics was carried out including means, standard deviations, proportions as well as graphs. Chi-square test was applied to test the association between inverted maxillary central incisor form and face form for the whole study sample. The null hypothesis assumed that there are no significant differences between groups. All measurements were done and recorded by one author.
| Results|| |
The sample size consisted of 164 participants with mean age (20.8 ± 1.81) ranged from 17 to 25 years. Most of the participants were females (84.1%). The most dominant age for males was 21 years and 18 years for females. The Chi-square value for the association between face form and tooth form was 10.89 with P = 0.092 (P > 0.05) which means that there was no association between tooth and face form in the study sample.
The percentage of individuals having the same tooth and face form was only 24.3% (9.1 + 13.4 + 1.8) [Table 1]. The mean values of the quantitative variables showed that the square-tapered tooth form was more frequent (50.6%) followed by oval (20.7%), square (17.7%), and the last was tapered form (11%) [Figure 1]. The oval face form was (51.2%) followed by tapered (25%), and the square-tapered form was the least frequent (23.8%) [Figure 2]. In relation to gender, the square-tapered tooth form was the most dominant in both males (57.7%) and females (49.3%) [Figure 3]. The predominant face form among males was oval and taper with the same percentage (38.5%). However, the predominant face form among females was oval (53.6%) [Figure 3].
|Table 1: Relationship between tooth form with face form among the study sample|
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| Discussion|| |
Essential factors, which contribute to patients' satisfaction with complete dentures, are that dentures should be pleasing and natural in appearance. However, for the edentulous patients with no preextraction records available, the selection of maxillary anterior teeth becomes very difficult, and controversy about the best method to employ for the selection of the anterior teeth still exists. As no universally accepted method for selection of anterior teeth has yet been established, dentists seek guidance from a variety of techniques using their clinical experience and esthetic sense to attain what is hoped will be an acceptable result. The Sudanese population is polygenic and is a mix of various races, cultures, and ethnic groups. In developing countries such as Sudan, problems such as nonavailability of preextraction records often hinder fabrication of dentures. This has led to several esthetic guides to aid in artificial tooth selection in the Sudanese population.,, There are also numerous methods and techniques for establishing the relation between face form and tooth form. To date, no reliable method has been found, but William's method is the most widely and universally accepted. In this study, the direct method for measurement was used to measure facial and central incisor horizontal distances, since some studies have revealed that neither facial nor anatomical measurements changed significantly with age. One of the disadvantages of the direct method for measurements of facial distances is soft tissue mobility; this can be considered as one of the limitations of this study. Therefore, to counteract those disadvantages that occur by direct method, care were taken not to press hard on the facial soft tissues during measurements, as well as taking three readings for each distance.
The number of females in the sample population (n = 138) is nearly 5 times the number of males (n = 26), but this comes as no surprise because the number of female dental students in Faculty of Dentistry, University of Khartoum, is much higher than males., Teeth measurements revealed an IW mean of 8.31 ± 0.75 mm, similar to the results of other studies., Upper central incisors were the narrowest at the cervix (mean = 7.66 ± 0.71 mm), while the width at the contact point and incisal edge were almost the same (8.47 ± 0.74 mm, 8.31 ± 0.75 mm) respectively, indicating that most common tooth shape in the Sudanese population is square-tapered. For facial measurements, the bizygomatic width was on average larger than the bitemporal and bigonial width, which revealed that the dominant face form in this sample was oval. These outcomes are in agreement with another study. In this study, four tooth forms (square, oval, tapered, and square-tapered), and only three face forms (oval, tapered, and square-tapered) were established. The square face form was not found in this study, which agrees with findings of other authors., Within the whole study sample, the most dominant tooth form was square-taper (50.6%), whereas the most common face form was oval (51.2%), which agrees with other study. The square-tapered tooth form was (57.7%) in males and (49.3%) in females. In males, both oval and taper face forms occurred in the same percentage of 38.5%, which differs to findings of another study, which revealed that square face form was the most dominant in their male population. These differences may be due to the small sample size of males in our study population. However, for females, the dominant face form was oval (53.6%), which is in agreement with findings of others. No significant association was established between inverted maxillary central incisor form and face form in our population sample of dental students at Faculty of Dentistry University of Khartoum. This is similar to other studies.,,, Only 24.3% of individuals had the same tooth and face form, which is similar to study by Varjão et al. in different four racial groups (Asians, Mulattos, Whites, and Blacks), a higher than those in the study by Ahmed, which showed only 10.4% correlation and less than other studies,, which revealed 35% and 31%, respectively.
| Conclusion|| |
Within the limitations of the study, the findings of our study indicate that William's law of harmony may be not efficient for selection of maxillary anterior teeth in Sudanese because nearly three-quarters of the study sample showed no correlation between tooth form and face form. Thus, it is recommended that dentists use their clinical experience and critical sense to reach good esthetic results in complete denture fabrication or complex anterior restorations.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]