Prosthetic Teeth Arrangement and Dental Arch Dimensions for Edentulous Patients in Saudi-Arabia

TABLE OF CONTENTS

ACKNOWLEDGMENT

ABSTRACT

ABBREVIATIONS

TABLE OF CONTENTS

LIST OF FIGURES

INTRODUCTION

AIMS AND OBJECTIVES

REVIEW OF LITERATURE

MATERIALS AND METHODS

FIGURES / PHOTOGRAPHS

RESULTS

TABLES

GRAPHS

DISCUSSION
Ideal Arch Form
Maxillary Arch Form
Mandibular Arch Form
Maxillary And Mandibular Arch Form/Shape Determination
Orthodontist Point of View on Dental Arch Forms
Genetic Influence
Anthropology Point of View
Arch Dimensions And Changes With Growth
Maxillary Incisor Tooth Form And Mandibular Arch Form Correlation
Dental Arch Perimeter
Indicies
Arch Dimensions – Arch Width
Maxillary And Mandibular Arch Widths And Lengths Measurements
Maxillary Arch Widths And Lengths Measurements
Mandibular Arch Width And Length Measurements
Maxillary And Mandibular Arch Lengths Measurements
Maxillary And Mandibular Arch Widths And Lengths Measurements In Children
Palatal Dimensions

Palatal Width And Depth Measurements
Palatal Width, Length And Depth Measurements
Structural Palatal Measurement
Virtual Measurements
Dental Arch Generator
Motion Analysis of the Dental Arch Generator

Objective Function of Control Point Optimization of the Dental Arch Generator
Constraint Function of Control Point Optimization of the Dental Arch Generator
The Optimized Design of Control Point Number for the Dental Arch Generator

Evaluation of Dental Arch Form Using 3D Dental Cast Scanning Technology
Description of the method
Multidisciplinary Approach
Prosthodontics Point of View
Maxillary and And Mandibular Arch Forms
Maxillary And Mandibular Arch Dimensions

SUMMARY

CONCLUSION

REFERENCES

ACKNOWLEDGMENT

To begin with, we thank the most merciful and beneficent, The All Mighty God…

We the authors Dr Pavan Kumar K R and Dr Mohammad Aljanakh would like to thank each member from the University of Ha’il in co-ordinance with The College of Dentistry, Kingdom of Saudi Arabia for providing the necessary facilities, co-operation and support to carry out this research work.

I Dr Mohammad Aljanakh, would like to express my gratitude to my parents, wife and children’s for their perseverance, constant guidance, support, encouragement and motivation.

I Dr Pavan Kumar K R would thank my grand parents, parents, beloved wife and my cute daughter for being my driving force in achieving greater heights in life.

Dedicated

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ABSTRACT

Title of Study: Maxillary and mandibular dental arch forms and arch dimensions in Saudi Population.

Type of the Research Design: Descriptive cross sectional survey.

Objectives: To assess various maxillary and mandibular dental arch forms and arch dimensions of Saudi population.

Materials and Methodology: Alginate impressions were made of the maxillary and mandibular arches of 100 dentate male and female subjects to obtain study casts. A standardized method was used to photograph the maxillary and mandibular dental arches on the study casts taken from each subject. The dental arch outline forms of the maxillary and mandibular arches were determined using a standardized method. The dental arch dimensions of the maxillary and mandibular arches were determined using Vernier Calliper. The mean of five prosthodontist’s evaluation was considered who classified the outline tracings of the maxillary and mandibular dental arches visually. The arch dimensions (widths and lengths) measurements were recorded and tabulated.

Statistical Analysis: Chi-Square test, Student ‘t’ test and Pearson’s correlation test were used and results tabulated.

Results: The most predominant maxillary dental arch form is square arch (40%) in males and both ovoid arch (42%) and square arch (40%) in females where as the most predominant mandibular dental arch form is square arch (>50%) in both males and females.

Male gender showed increased arch dimensions in both maxillary and mandibular arches as compared to females. The difference was found to be statistically significant except for maxillary anterior and molar arch lengths. A strong positive correlation (r=0.8, p<0.05) was observed between maxillary inter canine width and total arch length among females.

Conclusions: There was no significant gender difference seen within the dental arch forms among the population group studied. The determined maxillary and mandibular dental arch dimensions are useful in selecting accurate stock impression tray, selection and arrangement of artificial teeth among Saudi edentulous patients undergoing prosthetic rehabilitation.

Key words : Arch Form, Square Arch, Ovoid Arch, Tapered Arch, Arch Width, Arch Length, Arch Dimensions, Palatal Depth, Maxillary arch, Mandibular arch.

ABBREVIATIONS

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LIST OF FIGURES

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LIST OF GRAPHS

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INTRODUCTION

The achievement of dental esthetics is one of the prime objectives of prosthodontic treatment for edentulous patients. The key factor in achieving this goal is the determination of arch form, arch width, arch length and palatal contour.¹

Arch form describes the position and relationship of the teeth to one another in all three dimensions. It can be considered as a result of underlying skeletal morphology, the surrounding soft tissues, and any additional environmental effects.² The basic characteristics of arch form include the radius of curvature of labial segment, intercanine width and intermolar width.³

The dental arch form is defined as the curving shape formed by the configuration of the bony ridge.3 The dental arch shape and size undergo different changes throughout the growth of the supporting bones and the movement of teeth after their eruption, also the perioral muscles and the intraoral functional forces aid in the configuration of the dental arch.⁴,⁵,⁶ However, dental arch form and shape varies in individuals based on anatomic dimensions of the craniofacial skeleton.⁷,⁸

The majority of researches recognize that there is variability in the size and shape of the human arch form. Several methods and classification schemes have been developed to describe the dental arch morphology ranging from simple classification of arch shape, through combinations of linear dimensions to complex mathematical equations. But, the three basic arch forms that are commonly described by clinicians are tapered, ovoid and square arch forms.⁹

Arch perimeter is the distance from the mesial contact of one first permanent molar to its antimere as measured through the contact points or buccal cusp tips of all of the intervening teeth, ignoring those teeth that are malpositioned or blocked out so that the measurement represents an ideal arch form.¹⁰ The circumference or perimeter is one of the most important dimension of the dental arch and changes according to age and gender. The need for meaningful measurements of dental arch dimensions and their importance for diagnosis and treatment planning have been recognized since the early days of Angle. It was not until 1923 that the relationship of apical base and dental arch form began to be understood, as well as the realization that one of the most important diagnostic dental arch dimensions was dental arch perimeter.¹¹

Dental arch dimensions are not static; they change systematically during the period of intensive growth and development and less so in adulthood.¹²,¹³,¹⁴,¹⁵,¹⁶ Evaluation of dental arches is of great importance for definitive diagnosis and optimal craniofacial treatment. The values of the dimensions of the arch include: width, depth and circumference, intercanine and intermolar distances, overjet and overbite, which change during growth in different ways (the width of the teeth remains the same, whereas the lengths of the mandibular and maxillary bones increase). Also, the dental arch length varies with different races and gender.¹⁷,¹⁸

The Palatal vault is defined as the deepest and most superior part of the palate or the curvature of the palate.¹⁹ The form of the palatal vault gives an idea to the original form of the dental arch before removal of the natural teeth and resorption of residual ridge.²⁰

The knowledge of arch form in prosthetic dentistry as an anatomical parameter is of considerable reliance, especially regarding the positioning and selection of anterior teeth for artificial prosthesis, number and stress distribution pattern of dental implants and stability of any prosthesis in prosthodontics.²¹,²²,²³,²⁴

The knowledge of arch size in prosthetic dentistry will help the dentist in the selection of correctly shaped stock impression trays, the size of artificial teeth and overall form of the artificial dental arch at the wax trial stage that are amenable for modification by the prosthodontist.²⁵

As there are few studies²⁶,²⁷,²⁸,²⁹ done on determination of arch forms and arch dimensions in both males and females subjects in Saudi Arabian population, the present research study was conducted to determine the maxillary and mandibular arch forms, the palatal depths, the maxillary and mandibular arch width and the maxillary and mandibular arch length dimensions among male and female groups.

The results thus obtained would facilitate the accurate selection of stock impression tray, tooth selection and arrangement of the artificial teeth in an ideal dental arch form and dimensions that are closely related to each male and female edentulous patients of Saudi Arabian population.

AIMS AND OBJECTIVES

To determine predominant maxillary and mandibular arch forms in males and females of Saudi Arabian subjects.

- To compare maxillary and mandibular inter canine widths in males and females of Saudi Arabian subjects.
- To compare maxillary and mandibular inter first molar widths in males and females of Saudi Arabian subjects.
- To compare maxillary and mandibular inter second molar widths in males and females of Saudi Arabian subjects.
- To compare maxillary and mandibular anterior arch lengths in males and females of Saudi Arabian subjects.
- To compare maxillary and mandibular molar arch lengths in males and females of Saudi Arabian subjects.
- To compare maxillary and mandibular total arch lengths in males and females of Saudi Arabian subjects.
- To compare palatal depth in males and females of Saudi Arabian subjects.

REVIEW OF LITERATURE

A l-el-Sheikh HM , Al-Athel MS (1998) conducted a study to determine the relationship between inter pupillary distance, inter alar distance and the width of the six anterior teeth to be used as a guide during selecting the width of the six anterior teeth. 163 subjects were included in this study. A digital caliper used for facial and tooth measurements. The results showed a significant correlation between all measurements for the entire sample but when the sample divided into sex correlation found in female only, a significant difference between all measurements in both sexes was found. The average multiplying factor to estimate the width of the maxillary anterior teeth using inter alar width was 1.56 in this study.

Hassan AK, Najim ZN (2000) measured the dental arch of 220 Baghdad patients (120 females and 100 males) in the University of Baghdad dental clinic. Casts were made from alginate impressions. Specified points were noted, length and width measurements were taken on the casts. It was found that length measurements were smaller than width measurements indicating an ovoid shape arch. Also, the size of male arches was greater than those of females.

Smily PK, Nair KNV, Kumar CP, Nagaraj KR, Kumar MV (2002) conducted a study to analyze whether the gender difference exists in the harmony of tooth form to face form and tooth form to arch form on 60 dentate dental students in which 30 were males and 30 were females with age group 18-22years. Face forms and tooth forms were classified as given by William’s into square, tapering and ovoid. Hydrocolloid impressions of maxillary arch of the students were made and cast poured in dental stone. From these study models, arch form was visually analyzed and classified as square, tapering and ovoid arch forms. The data obtained was statistically analyzed. The result showed the harmony of tooth form to face form was similar only in square tooth forms in 6 (20%) males and in 9 (30%) females. It was concluded that harmony between tooth form and face form is predominant in females as numerical value only and no statistical significance was found. No theory or concept about artificial teeth selection may be universally accepted to all clinical situations.

Zilberman O, Huggare JAV, Parikakis KA (2003 ) performed a study was to test the accuracy of measuring casts with the aid of calipers or Ortho CAD and compare these two techniques. Twenty setups using artificial teeth corresponding to various malocclusions were created. Impressions were taken of them, providing 20 plaster and 20 virtual orthodontic models. Measurements of mesiodistal tooth dimension as well as inter canine and inter molar width were made on both. Additionally, values of tooth size were calculated from the isolated artificial teeth removed from the setups and of arch width from the existing setups. The resulting values were compared by the use of nonparametric statistics, and methods’ errors were also calculated. The results showed the methods being highly valid and reproducible for both tooth size and arch width. For the tested clinically applicable methods, measurement with digital calipers on plaster models showed the highest accuracy and reproducibility, closely followed by Ortho CAD. Digital calipers seem to be a more suitable instrument for scientific work. However, Ortho CAD’s accuracy is clinically acceptable, and most likely, considering its present advantages and future possibilities, the examined or an equivalent 3D virtual models’ procedure would become the standard for orthodontic clinical use.

Nakatsuka M, Iwai Y, Jue SS, OH SH, Guo L, Tominaga Y, Kumabe S (2004) evaluated the morphology of dental arches of 62(male:36, female:26) paired casts having normal dentitions and occlusion between age 18-26 years old. The maxillary dentitions were preliminarily classified as square, round square, round and round V shaped arches based on conventional morphological descriptions. After analysis, the result indicated that 1) 60% of maxillary dentitions were round square arches which showed no prominent principal component; 2) square maxillary arches distinctly showed a small value 3) round arches were characteristic by small values and 4) round V shaped arches had large values.

Thu KM, Winn T, Abdullah N, Jayasinghe JAP, CHandima GL (2005) estimated the maxillary arch measurements, to assess the validity of Pont’s & Korkhaus’ Indices; to determine the relationship between maxillary arch form with head form; and to estimate the cephalic index (CI) of the study population. A cross-sectional study was conducted on 85 mature Malay students, 28 male students (32.98%), 57 females (67.02%) attending Teachers’ Training College. Their mean age was 23.9 year, and Cephalic Index (CI) 86.4 (95% Confidence Interval 85.5-87.3). Arch and head dimensions were significantly larger in males than in females. CI was not significantly different between males and females. Means of anterior arch width (AAW), posterior-arch width (PAW) and arch-length (Lu) were 35.57mm, 47.3mm and 18.01mm respectively. They were significantly different from their corresponding Indices. Correlation Coefficient between bi-zygomatic width and anterior-arch-width was 0.18 and was not significant in both sexes of the present population.

Hashim HA, Al Ghamdi S (2005) The purpose of this study was to establish tooth width and arch dimensions in normal and malocclusion samples and to compare tooth width and arch dimensions between males and females in normal and malocclusion samples. A total of 120 pairs of orthodontic study casts were included in the study. An electronic digital caliper was used for the measurements. Descriptive statistics and the t-test were used for the statistical analysis of the data. Tooth width and arch dimensions were established in normal and malocclusion in the present study. Significant differences were found in tooth width between normal and malocclusion samples. However, no significant difference was observed in arch dimensions. Furthermore, there was statistical significant difference in tooth width between males and females where the males showed higher mean values. The same was true when arch dimensions were compared. The results of the current investigation are of great value to the anthropologist as well as to the orthodontist in understanding dimensional arch criteria and orthodontic arch wire selection. Furthermore, it helps the prosthodontist in the selection of the correct shape and size of stock impression trays and of suitable molds of artificial teeth for fixed and removable prostheses.

Ahmed ZM (2006) determined the ideal dimensions of the artificial dental arch by measuring the dimensions of dental arch of completely dentulous subjects and to find the relation of these dimensions to some facial measurements. The sample of study consisted of 54 completely dentulous adult subjects (24 females and 30 males) with Class 1 normal occlusion aged 19–24 years. Dental casts were taken for each subject and the dimensions of the dental casts and the facial measurements were made by using digital Vernier caliper. The data were analyzed with Statistical Package for Social Science program. The dimensions of the dental arches and the facial measurements of the male group were larger than that of female and there was high correlation between some dimensions of dental arch with some of the facial measurements. The width of the dental arches of the artificial dental prosthesis could be determined depending on the extra oral facial measurements as the percentage of upper inter canine distance to mouth width is 74.43% and the percentage of the upper inter first molar distance to bizygomatic width was 40.65%.

Petricevic N, Stipetic J, Antonic R, Borcic J, Strujic M, Kovacic etal (2008) The width and length of the anterior teeth, the dimensions of the frontal dental arches and the dimensions of the hard palate were measured (24 men and 56 women, age range of 18–30 years). The results showed gender-related dimorphism only for the cervical width of the maxillary canine, which were wider in men, p<0.05. The width-to-length ratios of the maxillary frontal teeth varied from 0.82 to 0.91. The tooth-to-tooth width ratios among different maxillary frontal teeth varied from 0.78 to 0.91. The sum of all anterior maxillary teeth widths was equal to the hamular width and to the distal maxillary arch width (p>0.05), meaning that the sum of the frontal artificial teeth width may be selected upon the measurement of the hamular width on the hard palate. The ratios between the maxillary and the mandibular frontal dental arch dimensions are representative values for the skeletal class I.

Ronay V, Miner M, Will LA, Arai K (2008) investigated mandibular dental arch form at the levels of both the clinically relevant application points of the orthodontic bracket and the underlying anatomic structure of the apical base. The correlation of both forms was evaluated and examined to determine whether the basal arch could be used to derive a standardized clinical arch form. Thirty five mandibular dental casts (skeletal and dental Class I) were laser scanned, and a 3-dimensional virtual model was created. Two reference points (FA, the most prominent part of the central lobe on each crown’s facial surface, and WALA, a point at the height of the mucogingival junction were selected for each tooth from the right to the left first molars. The FA and WALA arch forms were compared, and the distances between corresponding points and inter canine and inter molar widths were analyzed.

Both arch forms were highly individual and the tooth values scattered. Nevertheless, a highly significant relationship between the FA and WALA curves was found, especially in the canine (0.75) and molar (0.87) areas. Both FA and WALA point-derived arch forms were individual and therefore could not be defined by a generalized shape. WALA points proved to be a useful representation of the apical base and helpful in the predetermination of an individualized dental arch form.

Radzi Z, Yahya NA et al (2008) validated the use of digital dental study casts obtained from Cone beam CT Scan (CBCT) against gold standard; that is traditional dental study cast measured with digital caliper. Thirty-four study casts of Malaysian Aborigines were selected from Centre of Malaysian Pribumi Studies Databank. Palatal depth of each study casts were measured using Mitutoyo digital caliper. Subsequently, all the study models were scanned using i-CAT CBCT and the palatal depth were measured using i-CAT software. Data were analyzed using SPSS version 12.0 where intra class correlation and paired T-test were employed. There was no significant difference in palatal depth between CBCT and Mitutoyo digital caliper (p>0.05). Average measures for Intra class correlation is 0.753 indicate that it is consistently good. Within the limitation of this study palatal depth measurement produced by CBCT was as accurate as the digital caliper.

Ahmed ZM (2009) predicted the circumference of artificial anterior teeth depending on the palatal dimensions. The study sample consists of 30 female and 32 male with class I occlusion aged 19– 24 years .The dimensions of the palatal vault and the circumferences of upper anterior teeth were recorded with digital venire caliper and analyzed with SPSS program (version 11). A significant correlation was found between the dimension of the palatal vault and the circumference of upper anterior teeth. The angle of circumferences of upper anterior teeth of narrow short and deep palate will be more tapered than those one in the wide, long and shallow palate.

Rai R (2010) reviewed the selection of teeth for dentures to provide an aesthetically pleasing appearance is a challenge often encountered. Various anthropometric measurements have been utilized traditionally, which is subjective to each practitioner. Interalar width is one of the routinely used methods in the selection of upper anterior teeth. It is based on the premise that the parallel line drawn from the alae of the nose touches the tip of the canine. However this may not hold good for all type of arch forms. This paper finds a correlation between the alae of the nose and the tip of the canine for the various arch forms.

Ahmed N, Fida M (2010) compared the dimensions of dental arches among the three malocclusion groups and see the gender dimorphism in these dimensions. This was a cross sectional study conducted at dental clinics, the Aga Khan University Hospital, Karachi. A total of 110 patients belonging to different malocclusion groups were evaluated. Our inclusion criteria were 1) Presence of all permanent teeth from first permanent molar to first permanent molar 2) No previous orthodontic treatment and 3) Age range of 13-30 years. All patients suffering from some developmental anomalies and/or syndromes were excluded.

The mean maxillary inter molar, inter 1st premolar, inter 2nd premolar and inter canine widths and arch depth were 49.96mm, 40.13mm, 44.84mm, 34.02mm and 39.41mm respectively for the entire sample. The mean mandibular inter canine, inter 1st premolar, inter 2nd premolar and inter molar widths and arch depths were 26.90mm, 33.40mm, 38.72mm, 43.49mm and 33.72mm respectively for the whole group. Significant differences were found in maxillary inter-premolars and inter-molar widths among the three groups. A comparison between the two genders showed significant differences in mandibular inter canine and inter molar widths among the three groups.

A significant difference was found in maxillary inter molar and inter premolar widths among the three malocclusion groups. The Class III group had the largest maxillary inter molar and inter premolar widths followed by Class I group. Male subjects had significantly larger maxillary and mandibular inter molar widths and mandibular inter canine widths than females.

Loomba A, Agarwal P, Upadhyay U, Goel A, Sohal V (2011) study was undertaken to find if any correlation existed between the dental arch perimeter of samples with: Normal occlusion, Bimaxillary protrusion and Class 1 molar relation with anterior crowding. Digital Vernier caliper (Mitutoyo) was used to measure each cast in four separate segments. This study evaluated the mean arch perimeter by measuring the pre-treatment upper and lower study models of 30patients having two different types of malocclusion and a third control group. In the present study mean arch perimeter for upper arch with normal occlusion was 75.79mm(SD=2.32) and the mean arch perimeter for the lower arch was 66.97 mm (SD=2.67). Arch perimeter in class I bimaxillary and crowding cases was significantly more in both upper and lower arch.

Fares Al-Sehaibany (2011) conducted a study to: 1) Analyze the clinical crown dimensions of the maxillary anterior teeth with respect to their width, height, and width to height ratio. 2) Compare inter pupillary distance and bizygomatic facial width with the central incisors widths, and 3) Compare inter alar width and inter canine width between male and female adolescents. Two hundred sixty five subjects with age range from 16 to 18 years old were examined using full face standardized digital photographs for facial dimensions, and sectional plaster dental casts for maxillary anterior teeth measurements. The analysis of anterior teeth measurements and several facial widths were analyzed using the information obtained from both the computer images and the dental casts. Descriptive statistics and independent-sample t-test were carried out to summarize the data.

The results of this study showed that no statistically significant difference was observed for width to height ratios of the central incisors and canines between male and female subjects (P>0.05). However, a statistically significant difference (P<0.05) was observed between the male and female in width to height ratios of the lateral incisors. The ratios of inter pupillary distance to the width of the maxillary central incisors showed no statistically significant difference between the two gender (P>0.05). The inter alar width showed statistically significant differences between male and female subjects (P<0.01).The results of the current study are considered to be of importance to the clinician making treatment decisions for adolescents.

Al-Sayagh NM (2011) determined and compared the palatal dimensions of Iraqi adolescents with different Angle classifications in Mosul City, and to determine the correlation among the palatal dimensions.142 orthodontic models of school students aged 13 – 17 years with different occlusal relationships (class I normal occlusion, class II (division 1 and 2) and class III malocclusions). Eleven palatal parameters were measured by using dental Vernier and included; dental arch width at the canine, 1st premolar, 2nd premolar, 1st molar , arch depth at canine and 1st molar, palatal height at canine,1st premolar, 2nd premolar, 1st molar and arch perimeter. The mean and standard deviation were calculated, analysis of variance(ANOVA), Duncan's multiple analysis range test and Pearson's correlation coefficient were used for the statistical analysis.

The results showed, Class I normal occlusion had wider inter 1st premolar width and shallower palate at the canine, premolars and molar region as compared with malocclusion groups in both genders, while Class II division 1had narrower and higher palate than other occlusal groups. Class II division 2 had shorter canine and molar depth than other occlusal groups in both genders in addition Class II division 2 had smaller arch perimeter as compared to other occlusal groups in females. The correlation among palatal dimensions revealed that palatal widths, arch perimeter and molar depth were highly and positively correlated with each other, while palatal height measurements were only positively correlated to each other and negatively poorly correlated to other measurements in all occlusal groups except in Class II division 1 in males .This shows a highly significant correlation of palatal height at 2nd premolar and 1st molar with inter premolars and 1st molar width.

Differences exist in most of palatal dimensions among different types of malocclusion and Class I normal occlusion these differences may help to define the dental characteristics of these problems and simplify their therapeutic managements and palatal expansion may be considered before or during treatment class II division 1.

Shafique A, Saleem T, Chatta MR (2011) study determines and compares the frequency distribution and results of two methods establishing morphology of the dental arch form. It was conducted on 250 patients visiting Lahore Medical and Dental College, Lahore. The casts were measured and photocopied, which were analyzed first by using a mathematical model as advocated by Noroozi3 and then by superimposing orthoform templates to determine the arch forms. The dental arches were classified into square, ovoid, and tapered forms to determine and compare the frequency distributions between the two methods. The comparison between results of both methods was made by applying chi square test. Cross tabulation was done to observe the congruence of two methods on different arch forms. According to Noroozi’s mathematical model, frequency distribution of ovoid, square and tapering arch forms was found to be 82%, 64%and 11.2% respectively while according to orthoform templates those were 53.2%, 9.2% and 37.6% respectively. There was a statistically significant difference between results of two methods (P < .001). The ovoid arch form was most common arch form according to both methods. There was a statistically significant difference in the results of two methods as well as their frequency distribution.

Olmez S, Dogan S (2011) determined the distribution of morphological differences in the clinical mandibular arch forms seen in Angle Class I, II and III malocclusions in Turkish population and to examine the effect of gender on arch dimension parameters. This study conducted on pretreatment mandibular study models of 600 individuals (362 girls, 238 boys) aged between 14 and 19. On the photocopies derived from these models, 4 linear and 2 proportional measurements have been made. The samples have been evaluated as square, ovoid and tapered (OrthoForm-3M Unitek) arch form templates. The most frequent arch form encountered among all the groups was the tapered one (62.5%) followed by the ovoid (27.3%) and the square one (10.2%). Gender difference influences on morphological structure was apparent. Generally, compared with girls, arch width and depth were found to be more in boys. The most frequent arch form seen in Angle malocclusion groups was the tapered one, followed by the less frequent ovoid and square ones.

Kallianpur S, Desai A, Kasetty S, Sudheendra US, Joshi P (2011) compared two distinct races, Indians and Nepalese on the basis of facial height proportions, arch length and palatal rugae patterns and assess their significance in racial identification. A total of 120 subjects comprising of 60 Indians and 60 Nepalese were selected, with each group including 30 males and 30 females. Facial heights were measured using sliding digital calipers, arch lengths with the help of a brass wire and rugae patterns were traced on dental casts obtained with alginate impressions. Facial height measurements did not give significant results for racial or gender identification of given races. Differences between arch length parameters were found to be significant between the two population groups. Secondary and fragmentary palatal rugae forms were found to be more common in Nepalese than Indians. The Indian and Nepalese have similar anthropometric characteristics with regard to facial height. However, arch length and palatal rugae characteristics vary between the two races.

Othman SA, Xinwei ES, Lim SY, Jamaludin M, Mohamed NH, Yusof ZYM etal (2012) determined and compared the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups.120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular).18 buccal tips and incisor line angles on each model were marked, and digitized them using 2 dimensional coordinate system. Dental arches were classified as square, ovoid, or tapered by printing the scanned images and superimposing Orthoform arch templates on them.

The most common maxillary arch shape in both ethnic groups was ovoid, as was the most common mandibular arch shape among ethnic Malay females. The rarest arch shape was square. Chi-square tests, indicated that only the distribution of the mandibular arch shape was significantly different between groups (p = 0.040). However, when compared using independent t -tests, there was no difference in the mean value of arch width between groups. Arch shape distribution was not different between genders of either ethnic group, except for the mandibular arch of ethnic Malays. The ethnic Malays and Malaysian Aborigines have similar dental arch dimensions and shapes.

Shrestha R M (2013) analyzed the dental arch forms of Nepalese adults and to classify them into morphological types. Predetermined transverse and sagittal dimensions on dental stone models of one hundred Nepalese adults aged 17-32 years with normal occlusion and dentofacial proportion were measured using standardized Boley’s gauge. The analysis was done according to Raberin’s mathematical sixth degree polynomial method. The study compared the gender difference among the Nepalese samples.

The distribution of the Nepalese arch form types were; 26% flat arch, 24% wide arch, 19% pointed arch, 18% narrow arch and 13% mid arch. A considerable variation in distribution of dental arch form types found between Nepalese male and female samples and among population groups. The analysis enables the mathematical method that predetermines the dental arch form of the individual orthodontic patient.

Kareem FA, Rasheed TA, Rauf AM (2013) assessed the dimensional changes in the dental arches occurring during the transitional period from mixed to permanent dentition in individuals with normal dentition. A group of fifty children with normal dentition aged 8-9 years were selected according to specific criteria in Sulaimani city in Kurdistan of Iraq, dental arch dimensions were measured. Five years later, a second examination and measurement was performed to record the changes in dental arches. The data was analyzed by using statistical package for social sciences (SPSS, version 15) program for obtaining the descriptive statistics including the mean, and standard deviation, also the inferential statistics (t-test) was applied to test the significance difference between the dimensions.

The results showed an increase in the arch perimeter of the maxilla in the transition from mixed to permanent dentition for both males and females whereas in the lower arch it was the reverse. The arch perimeter differences between maxillary and mandibular arches show high significance in both mixed and permanent dentitions P(0.00), P(0.00). There was asymmetry in the ach length between right and left side for both mixed and permanent dentition and most of the measurements of the permanent dentition showed high significant differences between right and left sides. There was a significant difference P(0.00) in maxillary and mandibular left and right incisor canine distance (I-C) between males and females.

It was concluded that controlling the reduction of total arch length in the transition period from mixed dentition to permanent dentition may help in the early treatment of crowding of the teeth.

Budiman JA (2013) developed a qualitative arch form diagnostic references using artificial neural network from pre-post treatment dental cast scanning result. Pre-post orthodontic treatment dental casts (1990-2006) from Post Graduate Clinic Faculty of Dentistry University of Indonesia and 3 other orthodontists were gathered and scanned. Data were measured using Image Tool and analyzed using Stata9. ANOVA was used to compare arch forms (square, oval, tapered) and gender (male and female), with each component of arch dimension upper and lower jaw, before and after treatment; and also arch perimeter to kinds of treatment The results were compiled to determine variables in building the software for analyzing arch form qualitatively. The data from190 pre-post orthodontic treatment dental casts consisted of 42 male (22.1%) and 148 female (77.9%) treated without extraction (32.63%), 4 Premolars extraction (48.42%), Upper Premolars extraction (11.05%), atypical extraction (7.90%). Gender and all variables from pre treatment did not influence arch form, except kinds of treatment. Therefore, only post treatment data are included for arch form analysis. The shape of arch form (square, oval and tapered) can be described qualitatively by software using artificial neural network. This software could describe arch form with the accuracy of 76.3158%. This study concluded that Inter canine width, Canine depth, Inter molar width, and molar depth were variables that influenced arch form. A software using artificial neural network to describe arch form qualitatively could be used for diagnostic reference to Class I malocclusion orthodontic post treatment.

Al-Zubair NM (2013) assessed the dental arch forms of Yemeni adult sample. The Eucledian clustering method of analysis was utilized for the determination of dental arch form. A total of 398 study models were constructed and evaluated to do measurements for both arches using a modified sliding caliper gauge. Six dental cast measurements divided into three sagittal and three transverse measurements were utilized to represent the dental arch width and length measurements. The result showed narrow form is the most prevalent arch form (30.9%) followed by wide form (23.9%), their prominence appear more in females and the least prevalent arch form was the mid form (9.3%), while flat and pointed forms were in between 18.3% and 17.6% respectively.

A total of five arch forms: narrow, wide, mid, pointed and flat were distinguished as unique forms for the dental arches, with the predominance of the narrow arch form were found among Yemeni adults.

Padilla M, Tello L, Moreno F, Osorio JC, Bedoya A (2013) compared dental arch transversal and anteroposterior dimensions in three ethnic groups from Colombia. A digital caliper was used to take 16 transversal and two sagittal measurements, 9 for the upper jaw and 9 for the lower jaw. The sagittal measure determining arch length was drawn from a mesial line traced from first right permanent molar to first left permanent molar, and a perpendicular line from the point of contact between central incisive teeth, both for the upper and lower jaw. The dimensions of upper dental arch in the three ethnic groups showed differences in inter canine distance, as well as between premolar and between molar teeth. The same differences were found for lower dental arches. The populations evaluated show distinctive characteristics in dental arch dimensions, thus the Mestizo population had narrow arches while the natives had wide arches.

Soni VK, Soni S, Agarwal R, Agarwal S, Hardik , Kruti (2013) determined correlations between these measurements and to predict some of these measurements based on others. The dental casts of 30 patients (15 females and 15 males) with a mean age of 18 years (11 – 26 years) in the permanent dentition attending the Orthodontic Department of the Jaipur Dental College, Jaipur were selected. Inter canine width, inter molar width, and arch length on each dental cast were measured. Correlation between variables was determined using Pearson’s correlation coefficient. Linear regression analysis was applied and the 95 per cent confidence intervals for slope and intercept were determined. The data showed very high correlations between inter-canine width and arch length, both for the upper and lower arches and for males and females, r = 0.925. This coefficient was very close to 1, indicating a linear relationship. The regression equation for arch length and inter-canine width was arch length = 1.36 inter-canine width + 29.39 for both arches.

There was very high correlation between arch length and inter-canine width for the upper and lower arches and a regression equation between both magnitudes was established indicating that the size of one factor can be predicted by knowing the other. For an increase of 1 mm in inter-canine width, the arch length increases approximately 1.36 mm with a 95 per cent confidence intervals (1.30 – 1.42).

Maria CM, da Silva AMT, Stella ARB, de Paula BG, Berwing LC (2013) investigated the correlation between quantitative and qualitative methods of hard palate depth evaluation.74 children in mixed dentition phase were evaluated by speech therapist and dentist, who made the plaster models of maxillary dental arch used later for measure. The quantitative method was measurement of molar distance and molar depth whose values were used to calculate the Palatal Height Index. The hard palate was classified into low medium and high palate. Qualitative analysis was performed through visual inspection of the plaster models by three speech therapists with experience in Orofacial Myology. The depth of hard palate was classified as low, normal or increased. The result was the consensus of at least two evaluators. For Data analysis the frequency of ratings was investigated and the Gamma Correlation Test was applied.

The qualitative method: medium palate (55.4%) followed by low palates (39.2%) and high palate (5.4%). Quantitative method: high palates (51.4%) followed by medium palate (43.2%) and low palates (5,4%). The Gamma Correlation Test resulted in 0.6212 (p<0.05) which indicates moderate correlation. The correlation between quantitative and qualitative methods of hard palate assessment was moderate. There was a trend in the qualitative evaluation to consider the palates deeper than the quantitative method. Therefore, it is suggested that both forms of analysis to be used in clinical practice.

Hamdi AQ (2013) determined the maxillary arch dimensions in an Iraqi (Salah Aldin city) sample aged (17-27) years with CL I(class one) normal occlusion and show the sex difference in this sample and compare these values of this group (males and females) combined with other studies in middle eastern population sample( Saudi and Egyptian population sample).

The maxillary arch dimensions were taken from 80 study models (40males and 40 females) the measurement distances from canine to canine (C-C), molar to molar (M-M), molar to canine (M-C) and molar to incisor (M-I) according to Mack criteria . The measurements were made by means of Vernier calipers with sharpened points to the nearest 0.05mm. Statistical analysis of the collected data was performed; the t .test was used when two groups were compared and level of significance was chosen (p<0.05, p<0.01, p<0,001).

The greater mean values of inter cusp distances from canine to canine, molar to molar , molar to canine and molar to incisor were significantly higher in Iraqi males than Iraqi females , and this result is similar to result of sex difference in Saudi and Egyptian samples . While the comparison of the results of Iraqi and Saudi sample reveals no significant difference for Iraqi sample (both males and females) than for the Saudi sample (both males and females) in all measurements except (C-C) distance which shows significant difference. While higher statistically significant differences in (C-C), (M-M) distances for Egyptian sample than Iraqi sample while (M-I) difference is greater in Iraqi sample than Egyptian sample.

The Iraqi maxillary arch dimension was greater in males than in females. There is a similarity between the Iraqi and Saudi maxillary arch dimensions, except a very little difference in (C-C) distance. The Egyptian maxillary arch dimensions (African group) was greater than that of the Iraqi sample (Asian group) except in (M-C) distance which has no difference, while (M-I) distance the difference is greater in Iraqi sample than Egyptian sample.

Al - Zubair NM (2013) assessed the relationship between mandibular arch length and widths in a sample of Yemeni subjects aged (18-25) years. The investigation involved clinical examination of (765) adults; only 214 (101 females, 113 males) out of the total sample were selected to fulfill the criteria for the study sample (normal dento-skeletal relationship). Study models were constructed and evaluated to measure mandibular arch dimensions. The Spearman’s correlation coefficient (r) was calculated between the measurements of arch widths and lengths. Overall, the male group demonstrated greater transverse and sagittal mandibular dimensions; however, this was only statistically significant for measurements of inter first and second molar distances and anterior arch length (P < 0.05). Relatively stronger linear relationships were observed between the inter canine distance and mandibular arch lengths (P < 0.05), Spearman’s r is ranged between (0.17 to 0.50).

Among studied mandibular dimensions in subjects with normal dento-skeletal relationship, only inter canine distance demonstrated a week to moderate linear relationship with the mandibular arch lengths.

De ZY, Tao GJ, Gang JJ, Lian SX (2013) emphasized that during the manufacture of complete denture, the most important step is to design and generate the dental arch curve which adapts to the requirement of patients according to the jaw arch morphology of them. It is important to study the optimization method of the number and position of control point for the dental arch generator. This paper thus focuses on of the multi-manipulator tooth-arrangement robot. Quantitative model of the dental arch generator is established. On the basis of motion analysis of the dental arch generator, objective function, multivariate design and constraint function of control point optimization of dental arch generator is determined. Control point number of the dental arch generator is optimized. Single point error method of the dental arch generator is presented to realize the control point position optimization of the dental arch generator. Simulation results verify the feasibility of control point optimization method.

Daniel MJ, Khatri M, Srinivasan SV, Jimsha VK, Marak F (2014) determined and evaluated the usefulness of inter-molar arch width in gender determination and to validate its use as a forensic tool. Fifty subjects were selected and impressions were made for both the arches with alginate. Study models were prepared and used for analysis. Inter-canine and inter-molar width in maxillary arch for male and female were 35.22 ± 1.54 and 33.49 ± 1.49; and 48.74 ± 1.89 and 45.44 ± 1.92 respectively. Inter-canine and inter-molar width in mandibular arch for male and female were 25.58 ± 1.37 and 25.29 ± 1.50; and 42.45 ± 2.00 and 39.53 ± 1.87 respectively. Thus, these measurements were significantly higher in males. On using the Receiver Operating Characteristic (ROC) curve to deduce values with high specificity maxillary inter-molar arch width gave high specificity of 92% to detect gender correctly, with best sensitivity i.e. 64%. Therefore, concluded that inter-molar arch width is useful in determining the gender of dental remains accurately, of individuals with missing canine teeth.

Owais AI, Abu Alhaija ES, Oweis RR, Al Khateeb SN (2014) determined the most common maxillary and mandibular arch form and size in primary dentition stage. Four hundred thirty five preschool children were included in this study with an age range of 3.5-5.5 years old. Dental casts were digitized and landmarks for the measurements were identified and marked on each model. Ten points were determined on the dental arch. Measurements of the x and y coordinates of the 10 points of each dental cast image were plotted on a computer software to obtain the polynomial function that best describes the curve corresponding to the dental arch form.

Three arch forms were observed; square, oval and tapered. The most common arch form observed in the primary dentition was the oval form (52%) followed by the square and tapered arch forms (29% and 19%, respectively). Gender differences were not detected. In the maxilla, the most common arch form was the oval (58.4%) arch whereas the square arch form (46.7%) was the most common in the mandible. The medium size arch form was the most common size in both mandible (83%) and maxilla (71.5%) and for the total sample (77%). Differences in arch form size distribution were detected (P<0.000). Small size arch form was more common in females compared to males in the maxilla and total sample (P<0.000). Inter canine width was significantly smaller in the tapered arch form compared to oval arch form (P=0.048). In both arches, inter canine and inter molar widths were significantly larger in males compared to females.

The most common arch forms in the maxilla and mandible were the medium sized oval and square forms, respectively. Inter canine width was the smallest in the tapered arch form. Inter canine and inter molar widths were affected by gender.³⁰

Al Zubair NM (2014) conducted a study to assess the determinants factors of the dental arch forms of Yemeni adult sample. The Eucledian clustering method of analysis was utilized for determination of the dental arch form, 398 study models were constructed and evaluated to do measurements for both arches using the modified sliding caliper gauge. A total of 6 dental cast measurements were divided into three sagittal measurements and three transverse measurements were utilized, which represent the dental arch widths and lengths measurements. The narrow form is the most prevalent arch form 30.8% followed by wide form 24% their prominence appearance in females and the least prevalent arch form was the mid form 9.3%, whereas flat and pointed forms being in between 18.3% and 17.6 respectively. Five arch forms: Narrow, wide, mid, pointed and flat were distinguished as unique forms for the maxillary and the mandibular arches. It can be observed that the measurements related to the canine, have the widest range of reading and give the impression that the relation of canines to each other and to other teeth is the strongest factor in determining the dental arch form.

Al Zubair NM (2014) assessed the determinants of maxillary arch dimensions in a sample of Yemeni individuals aged 18–25 years. The study sample comprised 214/765 adults (101women, 113 men) who underwent clinical examination and fulfilled the study criteria. Study models were constructed and evaluated to measure maxillary arch and palatal dimensions. The majority of mean maxillary arch dimensions were significantly greater in men than in women with inter second molar distance showing the greatest difference and palatal depth showing the least difference. The measurements of palatal depth and relationships of the canines to one another and to other teeth thus had the widest ranges, implying that these dimensions are the strongest determinants of maxillary arch size.

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