Association between the Maxillary Arch Form and Length, Width and Depth of Palate in Malaysian and Indian Population. Type of manuscript: ResearchRunning Title: Arch form, Depth of palate, Malaysian population and Indian populationNurul Afiqah Amani Binti ZaabaUndergraduate studentSaveetha Dental College, Saveetha University, Chennai, India.Dr. Ashih R JainDepartment of ProsthodonticsSaveetha Dental College, Saveetha University, Chennai, India.Corresponding AuthorDr. Ashih R JainDepartment of ProsthodonticsSaveetha Dental College Saveetha University162, Poonamalle High Road Chennai 600077Tamil Nadu, India.E-mail: [email protected] number: +91-9884233423Total number of words: 2782AbstractBackground: Oral cavity composed of hard and soft palate. Proper development of soft and hard palate will help for the proper phonation and other functional activities along with the proper development of the teeth. Generally, different people will have different arch form and length, width and depth of palate. As this varies, the arch form and height palatine index of the individuals in different population will be differ.Aim: To investigate the relationship between the arch form of palate and length, width and depth of palate in Malaysian and Indian population. Materials and Method: The sample of this study consisted of a total of 30 adults individual of both gender. 15 of them are Malaysian population and remaining 15 people are Indian population. The participants that were selected for study were either of Malaysian or Indian populations, which were among non growing and post pubertal adults. The length, width and depth of palate as well as arch firmware calculated for this study.Results: It shows that 73% of Indian subjects had tapered maxillary arches, whereas only 47% of Malaysian subjects having tapered maxillary arches. In addition to this, only 20% of Malaysian subjects having squared maxillary arches form and none of the Indian subjects having this type of arch form. The remaining 27% of Indian subjects and 33% of Malaysian subjects having ovoid arches form. Almost 50% of Indian population having low type of palate and approximately 67% of Malaysian population having this type of height of palate too. Only 20% of Malaysian population having medium type of palate and remaining 13% having high palate. Whereas, about 33% of Indian population having medium palate and 20% of them having high palate.Conclusion: Tapered shape was the most common maxillary arch shape in both Indian and Malaysian population and low palate was the most common depth of palate in both population. Hence, there is no significant difference in relation to arch form and depth of palate in both populationKeywords: Arch form formula, depth of palate, maxillary arch form, palatine height index, populationsIntroductionEvery people in the world are very unique, as they have different characteristics and facial form. This features will help to distinguished each individuals from one another, based on their own characteristics. People in different countries also will have slightly different features and facial form from people of the other countries. Although their facial form may be different, generally it can be classified into three distinct categories which are mesocephalic , dolichocephalic and brachiocephalic. This classification can be widely used to categorise facial form and it is also related to dental arches of the individuals. Next, facial form is also part of the cranio-facial complex, in which the morphology of palate can be the key indicator of the anatomical structure in deforming the skeletal pattern 1. Generally, palate is located in maxillary region just beneath the nasal cavity and maxillary sinus. It consisted of two parts, which are soft palate and hard palate. Hard palate is a bony structure that form a partition between the oral cavity and nasal cavity 2, where as soft palate is a fibromuscular shelf composed of five muscles which act as a sling to posterior part of hard palate 3. Comparing both structures, hard palate is the most common and vital part which associate in production of speech as well as maintaining other oral functional activities, by maintaining its relation with other structures of the sensory-motor-oral system. It is also a bony part which associate with dentition especially maxillary teeth and give support to them. Poor development of the palate, may results to defect in development of palate which lead to a condition known as cleft palate. It also may associates with cleft lip. People with cleft palate also will have features of smaller maxillary arch, interdental width and also arch length when compare to normal group of people with permanent as well as mixed dentition 4. Therefore, this abnormalities and alteration of the depth of palate will give difficulties to them as they unable to speak or eat normally like other people. Thus, surgical intervention is needed to correct this. In relation to prosthodontics, palate is used as guidelines for replacement of the missing teeth. The assessment of depth of palate and also arch form is very important in selection of the artificial teeth. This is done, in order to construct and provide a better replacement of the missing teeth for the patient. Besides, the arch form of dentition is also a crucial portion of oral cavities as it influence the selection of artificial teeth and it also related to the facial form of the patient. Based on the facial form of the patient, their arch form can be easily identified. For example, brachiocephalic individuals usually will have broad dental arches, while dolichocephalic individuals will have long or narrow dental arches and mesocephalic individuals usually related with paraboloid or average dental form 5. In general, dental arch can be classified into tapered, ovoid and also square arch forms 6. In addition to this, the shape of dental arches also can be determined by activity of muscles 7 in adjacent structures like tongue.Besides using dental arch form and depth of palate as the indicators, there are also other factors which give influence in selection of artificial teeth. For anterior teeth selection, it is based on size, colour and form of the anterior teeth 8, while posterior teeth is based on size and form of teeth 9 only. These factors are particularly used for selection of artificial teeth which mostly used by all prosthodontists, when constructing a denture or implant. For the placement of the artificial teeth it is based on condition of alveolar bone and soft tissue of the edentulous ridge 10. Hence, complete assessment should be done in order to construct a proper denture or implant for the patient, so that it able to sustain for a long period of time and give comfort to the wearer. Next, dental arch form and depth of palate also is different from people in different region. Usually, people in different populations, will have some basic difference in their dental arch and shape. Thus, this study is focusing on two group of population which are Malaysian and Indian population, which are located in Asia region. Therefore, this study is conducted by focusing on the association of the arch form of palate and depth of palate in Malaysian and Indian population. Material and Method1.1 Sample size of the sample selectionThe sample of this study consisted of a total of 30 adults individual of both gender. 15 of them are Malaysian population and remaining 15 people are Indian population. The participants that were selected for study were either of Malaysian or Indian populations, which were among non growing and post pubertal adults. The sample size of this study was 30. It was determined by using G Power analysis and the formula used for this calculation was refer based on a study conducted by Charan J, as mention below. Sample size: Z 1? ? /2p2 p( 1 ? p ) d2According to this formula 11:Z 1? ? /2p2 is a standard normal variate.P value is based on proportion of studies model based on previous studies and the value was 0.048d is absolute error or precision and it is 0.08Therefore, Sample size: 1.962X 0.048(1-0.048). = 27.4 (round off to 30) 0.0821.2 Criteria of the sample selection Inclusion CriteriaMalaysian or Indian populationHaving permanent dentition Adult individual – Free from incised wear, tooth fracture, gingival hyperplasia as well as extensive and deep carious lesion on the teeth.Exclusion criteriaDoes not undergoes any orthognathic surgery or orthodontic treatment previouslyMixed or deciduous dentition No tooth fractureFree from extensive carious lesionAbsence of deep carious lesion on teeth1.3 Dental Cast AnalysisFor every subjects of the study, impression were taken using alginate impression material (Zhermack Tropicalgin Alginate 453g) and cast were poured by using dental stone (Samit DentalStone 1kg) . The casts were let dried and base former was used to make base for each dental cast by using Plaster of Paris (White Gold DentalPlaster 1kg). After they were sets, all of the casts were analyse for the study, based on palatal length, depth of palate and also width of palate.Length of PalateFigure 1: Measuring the length of palateThe length of palate of the sample were taken by using vernier calliper (Generic Mini Portable 100Mm Brass Vernier Calliper Double Scale Mm/Inch). It is measured from the anterior part of the palate which is from the linear contact point of the maxillary central incisors, (a), to the posterior part of palate which is the most distal point of the maxillary permanent molars (b) 5. This part can be determined by placing a stainless steel wire passing the distal part of the first molars and make sure it is perpendicular to palate.Width of PalateFigure 2: Measurement of width of palate The width of the palate were measured from the maxillary first molars of one arch to the opposite arch, at the level of edge of palatal gingival sulcus 2. This were done by using a vernier calliper (Generic Mini Portable 100Mm Brass Vernier Calliper Double Scale Mm/Inch). Depth of PalateFigure 3: Measurement of depth of palateThe depth of palate were taken as vertical distance which was imaginary line between palatal distance of two cusp and the deepest position of the palates specifically on the mid palatine suture. Two measurement of depth of palate were taken, they were depth of canine and also depth of molar in the cast. This were done by using a vernier calliper (Generic Mini Portable 100Mm Brass Vernier Calliper Double Scale Mm/Inch). For assessing the palatal height index, the palatal height of molar was used. It was calculated using the palatal height index formula as mention below. Based on the formula below according to the study conducted by Maria CM, the depth of palate were classified into three categories, which were 2:Camaestafilino (low palate): values less than or equal to 27.9 %Ortoestafilino (medium palate): values range between 28.0 % to 39.9 %Hipsiestafilino (high palate): values above 40.0 % Index of Palatine Height = Palatine Height X 100 Palatine Width IV. Arch FormArch form = CD X MW Or CD/MW CW MD MD/MWThe arch form for each cast were determined by measuring the inter canine width, canine depth, inter molar width as well as molar depth. Based on these findings, the arch form ratio was calculated based on arch form ratio formula as mention in Figure 1. The data was collected and analyzed. Each casts were then classified into three categories which were square, ovoid and tapered based on their ratio as shown below.Application of arch form ratio according to study conducted by Budiman JA 12:If arch form ratio is less than 45.30% – Square arch formIf arch form ratio is 45.30% to 53.37% – Oval arch formIf arch form ratio is more than 53.37% – Tapered arch form1.4 Statistical Analysis The data were collected and statistical analysis was done by using Microsoft Excel. The sample size of this study was 30 with p value of 0.075. Descriptive statistics were obtained by calculating mean, standard deviation, ratio as well as index. The Chi-square test was used to to compare the data and checked for the data distributions. The data were then recorded and tabulated in the tables demonstrated below. Results This study composed of 30 study models which were divided equally into two populations of people which are Malaysian and Indian populations. The levels of significance values used in this study was p < 0.075. Based on the data collected, the independent t-test results and comparisons of the arch dimension of Indian and Malaysian population show no significance different of the measurements between two population when it is evaluate carefully. (Table1and 2)Table 1: Comparisons of Arch Dimension Measurements of Indian Population and Malaysian PopulationSD: Standard Deviation, Chi-square test: 1.0Table 2: Comparison between Indian Population and Malaysian PopulationSD: Standard Deviation, Chi-square test: 1.0The frequency distribution of the arch form ratio between Indian and Malaysian population. It shows that 73% of Indian subjects had tapered maxillary arches, whereas only 47% of Malaysian subjects having tapered maxillary arches. However, in both population, majority of the subjects are having tapered form of maxillary arches. In addition to this, only 20% of Malaysian subjects having squared maxillary arches form and none of the Indian subjects having this type of arch form. The remaining 27% of Indian subjects and 33% of Malaysian subjects having ovoid arches form. The arch form ratios of both populations show significance difference when comparing their mean and standard deviation of three type of the arch form. (Table 3)Table 3: Comparisons of Arch Form Calculated by Ratio (CD/CW)/ (MD/MW) of Indian Population and Malaysian PopulationSD: Standard Deviation, CD: Canine Depth, CW: Canine Width, MD: Molar Depth, MW: Molar Width, Chi-square test: 0.00004Next, the palatine height index of both population were also compared. As seen in the table, most of the subjects are having low type of palate.Almost 50% of Indian population having low type of palate and approximately 67% of Malaysian population having this type of height of palate too. Only 20% of Malaysian population having medium type of palate and remaining 13% having high palate. Whereas, about 33% of Indian population having medium palate and 20% of them having high palate. The values between two populations almost shown similar results but with different distributions of data. (Table 4)Table 4: Comparisons of Palatine Height Index of Indian Population and Malaysian PopulationSD: Standard Deviation, PH: Palatal Height, PW: Palatal Width, Chi-square test: 0.235DiscussionsThe subjects in this study were equally distributed in which it is compromised of 15 subjects of Indian population and 15 subjects of Malaysian population, which give a total of 30 study models. However, they were not equally distributed between males and females study models. This study was focusing on two populations of people which are Indian and Malaysian population, which are in a different area. Different population, ethnic or race tend to have different arch form and depth of palate. Many studies have been conducted on dental arch form in relation to malocclusion, ethnic groups as also sex 13. Based on the dental arch form, there are various way to measure the arch form and it can be classified into three distinct categories. The most common method to be used is by using the vernier calliper on the dental cast models which was done in this study. Other method which can also be used to measure the arch form is by using computer digitising software, which were used in the studies conducted by Othman et al 6, Budiman et al 12, Celebi et al 13 and Owais et al 14. There are also many studies using fundamental therothetical formulae in measuring and describing the arch form, such as ordered logistics, ologit probability and also arch form ratio 12. In fact, the arch form also can be classified into ovoid, tapered and squared based the pattern of template 6,12. In this study, arch form ratio formula was used to describing the arch form of both population by measuring the landmarks on the study cast models.Generally, the basic arch form was classified by Chuck in 1932 into tapered, ovoid and squared arch form 15. This basic arch form is commonly used nowadays when describing about the arch form. The results of current studies clearly shown that majority of the subjects of both population consisted of tapered arch form. In Indian population, most of them having tapered arch form and remaining having ovoid arch form, without any squared maxillary arches. However, in Malaysian population although majority of them having tapered arch form, there were also some with ovoid maxillary arches and few with squared arches form. Next, the results of this study also shown that there was no statistically significant difference on transverse width of canines and molar of both Indian and Malaysian population. However, it clearly indicate that Indian people have deeper arch form in both canine and molar regions in comparison to Malaysian people. In addition to this, the frequency distribution of the palatine height index of both population shown slightly different in their distributions based on the depth of palate, but most of the subjects having low palate. There were no previous studies conducted found in correlation to both Indian and Malaysian population.Basically, the depth of palate can be describe in both quantitative and qualitative method. Although quantitative method is convenience, it is more subjective and does not give definite results when compare to qualitative method. There were also possibility for the evaluators to rank the palate higher that its real position as it being subjective. Therefore, this study was done by using quantitative method through application of palatine height index formula 2. On top of that, by determining the palatine length, width and also height, it also can be utilized for the ethnic as well as racial classification of crania and anthropological studies 16.Next, in relation to palatine measurement, when there is increased in the length of palate it usually associated with increased in the depth of palate. On the other hand, the circumference of upper anterior teeth (inter-canine distance) is directly related to posterior palatal vault but inversely related to length and depth of palate. Hence, originally broad and shallow edentulous palatal vault is indicated for shallow arch form, while V shape edentulous palatal vault is indicated for tapered arch form and ovoid dental arch form will have rounded palatal vault 17. This is very important point to be noted when replacing missing teeth with artificial teeth.In relation to prosthodontics, both arch form and depth of palate is very important for the selection of artificial teeth, apart from the selection of teeth. According to GPT 8 arch form is define as " geometric shape of dental arch when viewed in the horizontal plane (square, tapering, ovoid, etc.)" 18. Whereas palatal vault which is a part of the hard palate is defined as " the deepest and most superior part of the palate or the curvature of the palate" 18 based on GPT 8. According to Boucher, the dental arch form of an individual will be maintained even after removal or extraction of the natural teeth 19. In a Nelsons "esthetic triangle" theory, stated that there is close proximity between the face, tooth, arch and alignment, however based on previous studies it shows less significant and definite 20. Although it may not show definite results, it is still important for selection of artificial teeth. Conclusion Tapered shape was the most common maxillary arch shape in both Indian and Malaysian population and low palate was the most common depth of palate in both population. In Indian population, most of the participants have high palate and small width, whereas Malaysian people tend to have greater width and low palate. Overall, there is no significant difference in relation to arch form and length, width and depth of palate in both population. In a nut shell, both arch form and depth of palate is important and related to each other, especially for selection of artificial teeth.References1 Al-Qudaimi NH, Ali FA, Made AA and Al-Sanabani FA. Palatal depth in normal occlusion in class-I with dental crowding for a group of Yemeni school children. Austin Dent Sci. 2016;1(1):10052 Maria CM, Silva AMT, Busanello-Stella AR, Bolzan GP, Berwig LC. 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