Evaluating Maxillary Anterior Teeth Measurements, An Aesthetic-Smile Interdisciplinary Approach Guidelines, Among Jordanians

Evaluating Maxillary Anterior Teeth Measurements, An Aesthetic-Smile Interdisciplinary Approach Guidelines, Among Jordanians

Tamara Alzoubi;BDS*, Ahmad Izzeddin Aldalalah; BDS*, Zaid Ali Fahid Alzyoud; BDS*, Saja Tayseer Mohammad Alnsour; BDS*, Yousef Ehab Rasas, BDS*

Abstract

Introduction: Tooth dimension is important in clinical diagnosis and treatment planning and is an essential guideline in aesthetic-smile interdisciplinary approaches

Aim: The aim of this study was to measure the dimensions of the maxillary anterior teeth in a sample of the Jordanian population and to compare it to other ethnic groups such as European, Chinese, Asian, and White populations.

Materials and Methods: Three hundred and eighty-six (193 male and 193 female) Jordanians with intact maxillary anterior teeth (age range = 12-35 years) participated in this study. Full arch stone casts were obtained for each participant from alginate impressions. The width and length of the 2316 upper anterior teeth on the dental casts were measured, using a digital calliper (in millimetres) The shapes have been compared as well with multiple ethnic groups such as Chinese and Asians.

Results: The mean width of the central incisor was 7.99 mm (male = 7.98 mm, female = 8 mm), lateral incisor was 6.28 mm (male = 6.27 mm, female = 6.29mm) and canine was 7.38 mm (male = 7.36, female = 7.41mm). The mean lengths of these teeth were 8.96 mm (male = 8.92 mm, female = 9.00 mm), 7.59 mm (male = 7.57 mm, female = 7.62 mm) and 8.66 mm (men = 8.6 mm, women = 8.72 mm), respectively. The crown width to length ratios for these teeth were 0.90, 0.83 and 0.86, respectively. No significant differences were found due to gender nor between the right and left sides.

Conclusions: The maxillary anterior teeth in Jordanians are smaller than most of the other ethnic groups such as European, Chinese, and Asian. A squarish form of anterior teeth with ratios similar to those of the Saudi and the Turkish populations.

Keywords: Maxillary anterior teeth; Anterior teeth dimension; Dental aesthetics.

JRMS DECEMBER 2025 Vol 32 (3):10.12816/0062297

Introduction

An aesthetic smile is reported to be one in which the shape, size, colour and position of the teeth are in proportion, harmony and relative symmetry to each other, their surrounding framing elements and the face.¹ Depending on the existing situation, changing current tooth dimensions and positions to create a more aesthetic smile might require team work (restorative work, periodontal procedures, orthodontic treatment, osseous and orthognathic surgery, and prosthodontic rehabilitation that might include changing the occlusal vertical dimension).² Therefore, to have the best comprehensive dental treatment for our aesthetically driven patients, the paradigm has shifted towards interdisciplinary

approach,³ in which the skills and expertise in the different dental disciplines are synergised and utilised, to ensure a correct diagnosis, expanded treatment options and higher quality of work.⁴ Several interdisciplinary treatment planning concepts have been developed over the years, including the interdisciplinary dentofacial therapy (IDT) model by Dr Roblee,⁵ facially generated treatment planning (FGTP) approach by Dr Frank Spear and Dr John Kois⁶ and Global diagnosis by Robbins and Rouse⁷, in which maxillary anterior teeth (MAT) measurements play an important role as a diagnostic and treatment plan guidelines

From Department of:

*Department of Conservative dentistry

Correspondence should be addressed to Dr. Tamara alzoub        Tel: +962772444870   E-mail :alzo3bi.tamara @outlook.com

According to the IDT model there are seven fundamental components of dento-facial problems: dental, periodontal, alveolar, skeletal, temporomandibular, facial soft tissue and systemic,⁵ where the MAT measurements form one of the parameters that need to be inspected to identify whether the dento-facial problem is of dental component origin.⁵ As for the FGTP approach, tooth size relative to the projected incisal edge position determines the correct gingival levels.⁸ In global diagnosis, MAT measurements are one of the five parameters that need to be assessed (facial height, lip mobility, gingival line, tooth size and cemento-enamel junction) to reach the correct diagnosis⁷ and consequently identify a correct treatment plan.

Because of its importance, as noted above, MAT width, length, and crown width to length (W/L) ratios have been extensively studied and reported in dental literature;^9-14 however, these reports conveyed variable results, which could be attributed to gender and ethnicity¹⁵. There were many studies which support sexual dimorphism in human dentition,^(14-17) yet some reports demonstrated no correlation between tooth dimension and gender.¹⁸ Regarding ethnicity, which has been proven to be a plausible factor effecting MAT measurements, only a few studies compared the MAT measurements of different ethnicities and reported the differences ^19,20. Based on this, the selection and application of teeth size should be established using research studies carried out in the same population group.²¹ A number of studies have reported MAT dimensions^22-25 among Jordanians, but these mainly assessed the MAT mesiodistal width and did not take the other parameters into consideration. There are few valid MAT guidelines available specifically for Jordanians to aid in selecting the proper size and shape of these teeth, identify the proper gingival level and determine the correct diagnosis. Thus, the objective of this study was to fully analyse the MAT dimensions in terms of width, length and crown W/L ratio in the adult Jordanian population and obtain information or a norm that will be most appropriate for local patients. Thus, this will be a useful tool in establishing the optimal anterior teeth dimensions for Jordanian patients, which can be utilised in various clinical dental applications and interdisciplinary approaches, especially concerning smile design.

2. Materials and methods

Ethical approval was acquired from the Royal Medical Services Ethical Committee. Written informed consent was obtained from all participants in this study. In cases where subjects are under the age of 18, written informed consent was acquired from each patient’s parent or legal guardian.

2.1 Study design and sample:

This cross-sectional descriptive study was conducted from December 2022 to April 2023. With a sample size of three hundred and eighty-six Jordanians (193 males and 193 females) ensuring that there is no sex bias effect and guaranteeing a 5% margin of error and 95% confidence level survey,²⁶ estimating that the Jordanian population in 2023 is about 10,500,000²⁷. The participating subjects were patients attending Royal Medical Services Dental Clinics in three different regional hospitals: King Hussein hospital( Capital ), Princess Haya Hospital ( north), Prince Zaid Hospital (South), who volunteered to participate in this study, with an age range of 12–35 years. We ensured inconsiderable natural tooth surface loss²⁸ and a better representation of the Jordanian population.

After obtaining consent, a maxillary alginate impression was taken for subjects who fulfilled the inclusion criteria in Table 1.

2.2 Impression and measurements

Alginate impressions (Cavex Cream alginate, Cavex Holland BV,The Netherlands) were taken using standard mixing procedures, impression was ­­

Measurements of the width and length of the six upper anterior teeth was performed using Digital Vernier callipers(Fuzhou conic industrial co.,LTD, china)  with precision readings to the nearest 0.01 mm (image 1). To measure the crown’s length, the clinical crown length were measured which is the distance between the gingival zenith (the most apical point of the marginal gingiva) and the incisal edge or the most incisal point of the crown, on a line parallel to the long axis of the tooth⁹. The main difference is in the method of measurement: clinical crown length is determined in a medical environment, taking the tooth's placement in the mouth into account, whereas anatomical length refers to the physical measurements of the crown of the tooth.  As for tooth width, it was the maximum distance between the contact points of the proximal surfaces of the dental crown, with the callipers parallel to the occlusal and buccal surfaces²⁹. All measurements were of labial surfaces of the teeth and were in millimetres. With regard to the width-height ratios, they were calculated from the measurements evaluated above for all maxillary anterior teeth.

All measurements were carried out by a single examiner to eliminate inter-observer error. Measurements were repeated at least three times, or until a consistent value was obtained, to avoid intra-observer error and measurements were limited to ten casts at a time to limit fatigue errors.

2.3 Assessment of measurement errors

Before the study, intra-examiner error was evaluated by taking two measurements with 15-day intervals of 40 randomly selected study casts of the participants. Frequency means and standard deviations were measured. Comparisons between groups were made by the unpaired t-test. Level of significance was set at 0.05 and a p-value < 0.05 was considered significant using Statistical Package for Social Sciences Software (SPSS® for Windows version 20, SPSS Inc., Chicago, III., USA); assessment of random error was established using the index of reliability by correlating repeat measurements (Houston, 1983)⁵⁷. Error analysis revealed no significant intra-examiner differences (p > 0.05) and correlations of repeat measurements were found to be greater than 0.95, signifying the absence of random error.

2.4 Statistic analysis

Statistical analysis was performed using SPSS v21 software. Descriptive analysis was carried out on MAT measurements of each tooth and on paired right and left corresponding teeth. Paired sample t-tests were conducted to collate right and left mean values obtained for the male and female participants. Independent sample t-tests were performed to identify the presence of gender differences in the width, length, and W/L ratio for each tooth . Statistical significance was set at P < 0.05.

3. Results

Table 1: Inclusion criteria

Table 2 provides information about the age distribution of 386 samples, split evenly between 193 males and 193 females. The mean age of males is 21.30 years, and the mean age of females is 21.00 years, with the overall mean age being 21.20 years. The median age for both genders is 20.00 years, with the standard deviation for males being 5.82 years and for females 6.03 years. The overall standard deviation is 5.93 years. The minimum age recorded is 13 years for males and 12 years for females, and the maximum age for both genders is 35 years

Table 3 provides a detailed statistical analysis of the width, clinical crown length, and width-to-height ratio (W/L) for three types of teeth: canines, lateral incisors, and central incisors. The data, based on 772 measurements for each tooth type, includes mean, median, standard deviation, and range (minimum to maximum values). The mean W/L ratios are 0.86 for canines, 0.83 for lateral incisors, and 0.90 for central incisors, indicating a consistent proportion across different tooth types. The table likely serves as a reference for dental morphology, offering insights into the average dimensions of these teeth in a given population

In Table 4 you can find the values, for the width, height and width-to-height ratio (W/L) of canine lateral incisor and central incisor teeth. These values are categorized by gender. The findings show that when it comes to canines females tend to have average width (7.41 mm) and average height (8.72 mm) compared to males (7.36 mm and 8.60 mm respectively). However, the W/L ratio remains consistent for both genders at 0.86. For incisors, females have a width of 6.29 mm while males have an average width of 6.27 mm. Additionally, females exhibit an average height (7.62 mm) compared to males (7.57 mm). The W/L ratio is the same for both genders at 0.83.

As for incisors females have a width of 8.00 mm whereas males have an average width of 7.98 mm with slight variations between them in terms of height. Females have a higher mean height of 9.00mm while males measure at approximately 8.92mm on average. The W/L ratio is calculated as being equal to 0.89. Approximately O.90, for females and males respectively

Table 5:

From table 5, it’s clear that when it comes to incisors their average width measures 8.00 mm, on the side and 7.98 mm on the right side. Similarly, the average height is 8.97 mm on the left and 8.95 mm on the right. The width-to-height ratio remains constant at 0.90 for both sides. In general, this data suggests that there is a level of similarity in tooth dimensions between the right sides of the mouth with only minor variations. These findings could potentially have implications, for assessments and orthodontic treatments that require tooth measurements.

Table 6: Independent Samples T-Test measuring the presence of significant differences in tooth measurements between males and females

In Table 6, the information presents the statistical analysis results obtained from an Independent Samples T Test that compared tooth measurements, between males and females. This test focused on aspects such as width, height and the ratio of width to height for teeth including left and right canines, lateral incisors and central incisors. The findings indicate that there are no differences between genders in most of these measurements. The p values obtained are above the used threshold of 0.05 for statistical significance. However,, it is worth noting a trend towards significance, in the height measurement of the canine (p=0.090) which might suggest a potential difference that warrants further investigation. Overall based on the examined metrics it seems that males and females have tooth dimensions.

Table 7: Paired Samples T-Test measuring the presence of significant differences in tooth measurements between the left and right sides

In Table 7 you can find a summary of the results, from a Paired Samples T Test that investigated if there were any variations in tooth measurements between the right sides. The measurements included width, height and width to height ratios for teeth such as canines, lateral incisors and central incisors. After analyzing all the tooth types and measurements the findings showed no differences between the two sides. The p values ranged from 0.214 to 0.874 indicating that there is symmetry in terms of dimensions, between the right sides of the mouth.

Abbreviations:

CI - Central Incisors, LI - Lateral Incisors, C - Canines

Image 1: Digital Vernier calipers with precision reading to the nearest 0.01 mm

This study was composed of 386 Jordanian subjects (193 of each sex) from the capital, northern and southern regions of Jordan with a mean age of 21.20 (as shown in Table 2).

3.1 Morphological Assessment of Teeth (MAT) between Genders:

This study was composed of 386 Jordanian subjects (193 of each sex) from the capital, northern and southern regions of Jordan with a mean age of 21.20. 

3.2 MAT on Different Jaw Sides:

The research discovered that there were no variances, in the dimensions of MAT ( anterior teeth) between the right and left sides of the participants. This data holds value for professionals who are involved in restoring front teeth as it offers valuable insights into the variations between both sides of the jaws, in Jordanian individuals.

3.3 Comparison to other ethnicities When comparing the measurements of the teeth, in the jaw (known as maxillary anterior teeth) among different ethnic groups this study discovered that the width-to-length ratios of the canine, lateral incisor and central incisor were 0.86, 0.83 and 0.90 respectively for the Jordanian population. These ratios are similar to those found in populations from Saudi Arabia and Turkey suggesting a square-shaped appearance of these teeth in these populations. Additionally, it emphasized how ethnicity influences the measurements of teeth by highlighting differences when compared to European, Chinese, Asian and White populations.

In Table 3, a descriptive analysis of MAT height, width and W/L ratio is illustrated. The results show that the average W/L ratio of the central, lateral incisors and canines were 0.90, 0.83 and 0.86, respectively.

Regarding male and female MAXILLARY anterior teeth measurements, there were negligible differences between male and female tooth measurements, as the average male W/L ratio of the central, lateral incisors and the canines, irrespective of their corresponding side, measured 0.90, 0.83 and 0.86, respectively, while the measurements in females were 0.89, 0.83 and 0.86, respectively (Table 4). The average female central, lateral incisor and canine values, regardless of their corresponding side, were slightly taller than for male teeth, but again with negligible differences; for females it was 9.00 mm, 7.62 mm and 8.72 mm, respectively, while for males it was 8.92 mm, 7.57 mm and 8.60 mm, respectively (Table 4).

Concerning the corresponding left- and right-side teeth, the W/L ratio of the central, lateral incisors and the canine on the left and the right side were more or less the same, with values of 0.90, 0.84 and 0.86, respectively, on the left side and 0.90, 0.84 and 0.86, respectively, on the right (Table 6 ).

Table 6 represents the MAT measurements in a more explicitness manner where the different MAT measurements of the right and left individual teeth in separate genders were illustrated . The results indicate that the height of the left central incisors in males was 8.94 mm, but was 9.00 mm in females, whereas it was 8.90 mm for the male right central incisor and 9.00 mm in females. Further MAT measurements are shown in Tables 2–6.

The results of the independent sample t test (Table 7) show no significant differences between males and females, and there were also no significant differences between the participants’ right and left sides, as measured by Paired sample t-tests (Table 8).

Discussion

Morphological Assessment of Teeth (MAT) between Genders:

The present study investigates the MAT dimensions/measurements (width, length and W/L ratio) in a sample of 386 Jordanian subjects, comprised of an equal number of males and females from different regions of Jordan. This is one of the largest studies to investigate MAT dimensions (Table 8). The aim was to describe MAT dimensions in a sample of the Jordanian population. The comparison of the right and left teeth measurements and between genders was also performed in order to employ this information when restoring anterior teeth. The results of the current study for MAT dimensions may yield useful information concerning MAT norms in the Jordanian population, thus helping and guiding the dental clinicians towards a proper diagnosis and the correct treatment plan to provide an optimal, natural appearing dental aesthetic to their patients(Table 8).

MAT on Different Jaw Sides:

The measurements of this study were performed on studies of casts of intact teeth that were poured from alginate impressions, a method which was reported in previous studies.^10,30-31. Immediately poured alginate impressions were generally stable,³² meaning that clinical measurements should not be expected to necessarily be more accurate than those obtained from plaster models.³³ Study model measurements have been demonstrated to be more reliable than measurements directly executed in the mouth³⁴ and measurements of intact teeth rather than extracted ones provide a better “clinical," value in terms of considering the impact of soft tissue and adjacent teeth on the measured values¹⁵. Dental aesthetics deals with perception and apparent composition rather than isolated and actual measurements¹⁵.

Comparisons with Other Ethnicities:

In this study, 386 individuals were from Jordan with mean age of 21.20 were involved. When examining the measurements, for the incisors and canines we found the following average width-to-length ratios; 0.90, 0.83 and 0.86 respectively. We conducted paired sample t-tests to compare the values of these measurements between the right and left sides of the mouth. Additionally, independent sample t-tests were used to explore any gender differences in width, length, and width to length ratio for each type of tooth. The results showed no differences in these measurements between males and females.

It is worth noting that previous research studies have extensively examined MAT width, length and width-to-length ratios in literature. However, there has been reported variability in these results that can be attributed to factors such as gender and ethnicity. Ethnicity was particularly emphasized as few studies have compared MAT measurements among groups. This study focuses on establishing teeth size selection and application based on research conducted within the population group is crucially important. It is also noteworthy that previous studies on MAT dimensions among Jordanians mainly focused on width without considering parameters. The reported width and length of MAT for the Jordanian population were smaller than that reported in different ethnicity ^9-13,35 These differences could be attributed to environmental and hereditary factors. The mean tooth length of the present study was smaller by more than 2mm than those measurements presented by Magne et al.¹²; large differences in length may be attributed to the fact that the measurements of Magne et al. were taken using a different population and the study was conducted on extracted teeth.

In this study, the reported width and length of MAT for the Jordanian population were smaller than that reported in different ethnicity ^9-13,35 These differences could be attributed to environmental and hereditary factors. The mean tooth length of the present study was smaller by more than 2mm than those measurements presented by Magne et al.¹²; large differences in length may be attributed to the fact that the measurements of Magne et al. were taken using a different population and the study was conducted on teeth.

MAT dimension gender variation was not established in this study. Gender variations in the MAT dimensions have been an ongoing debatable topic. It has been reported in many previous studies for most racial groups,^9-17,36-39 and ceased to exist in other reports^18,40,41 . Gillen et al.¹⁵ documented that the MAT of men were longer and wider than those of females in both white and black populations. Similarly, Sterrett et al.¹⁴ noted that the average width and length of men’s MAT clinical crowns is significantly larger than that of females in a white population. Furthermore, an accurate formula that resulted in 80–0.90 accuracy when predicting the gender of a number of isolated populations remains (i.e., Melanesian population individuals and Arikara Indian skeletons) was formulated based on dental morphologic measurements and multivariate statistical analysis^42-44. However, it is worth mentioning here that the formulae could not be applied to all populations as it was only specific for those isolated populations, with some populations showing no relationship between gender and MAT dimension; also, the most predictive teeth for gender determination in these studies were the posterior teeth, specifically the buccolingual dimensions, as explained by Gillen et al.¹⁵. On the other hand, Leung et al.¹⁸ and Kalia⁴⁰ found no sexual dimorphism between males and females in their studies, while Frayer and Wolpoff¹⁹ (p.453) cited that “canine dimorphism cannot be matched in any living or fossil anthropoid species”, which was in agreement with our finding. These controversial results could be explained by the fact that most of the above studies did not take into consideration the angles classification of the studied sample which was found to have a great impact regarding this debate. Krishan et al., in their study, found that sexual dimorphism was predominant only in the Class III malocclusion group and that there was no significant gender variation for the majority of teeth for Angle’s Class I and Class II division I⁴⁵. This finding was reinforced by Leung et al.¹⁸ who carried out a study on people with class I Angle classification and found that sexual dimorphism ceased to exist in that specific group of people. Since neither our study nor the previous studies that had report sexual dimorphism of individual teeth have taken into consideration Angle’s classification of their participants, data from certain studies might be in favour of gender variation whereas others are not based on the most prevailing Angle classification of the participants.

When reviewing the symmetry of the corresponding right and left MAT regarding their length and width, the present study revealed minor variations with no significant differences. Some previous research studies were inconsistent with our findings and reported major differences between the dimensions of the corresponding right and left side teeth. Mavroskouvis and Ritchei⁴⁶ measured right and left central incisors in 70 students and found that 86–0.90 of the examined subjects demonstrated dimensional differences in these teeth. Overall, 60% of subjects, had considerable differences, with few patients being found to have a difference of more than 1 mm. Chu⁴⁷ also found asymmetry between right and left teeth measurements, but this was considered insignificant. However, a systemic and meta-analysis study by Wang et al.⁴⁸ reviewing related articles came to the conclusion that there was no difference between the sizes of the right and the left teeth, which supports our results. This is inconsistent with the aesthetic principle of symmetry that could be useful in helping patients to attain a natural dental appearance. For instant, in treating patients with missing MAT, the contralateral tooth could be used as a reference point or when dealing with spacing in the upper anterior arch, where the upper anterior right and left sides will be divided equally maintaining the central incisors contact points along the facial midline and distributing the spaces equally on the left and the right side

As stated by researchers, the crown W/L ratio is the most stable reference,^9,10,13 with minor differences between the genders or between teeth^49,50. In this study, the W/L ratio for the maxillary central incisors, lateral incisors and canines were (0.90),(0.83) and (0.86), respectively, with no differences found between corresponding teeth and different genders. Similar results were reported in a study by Alqahtani et al.³⁵ in the Saudi population. However, the results were that length of the MAT were incomparable when compared to the European, Chinese, Asian, and White populations,^9,12,13,19 which might be due to racial differences in the studied population.

MAT measurements are greatly influenced by ethnicity, as shown by Tsukiyama et al.,¹⁹ when he performed a homogeneous comparison between two ethnic groups; he found that the W/L of MAT in Caucasian populations was larger than that in Asians. The analysis of Maxillary Anterior Teeth (MAT) measurements, across groups reveals that ethnicity plays a significant role in determining the shape and size of teeth. Our research observed that the Jordanian population had a like shape for MAT, similar to the Saudi and Turkish populations when comparing their width to length ratios (W/L). This suggests that these populations share tooth shapes. Our findings also align with Tsukiyama et al.'s work, which showed that Caucasian populations have W/L ratios for MAT compared to Asians. This highlights how ethnicity influences the dimensions and shapes of teeth.  Significant differences between MAT measurements of different ethnic groups were also reported by Owens et al.³⁹. In this study, the investigated Jordanian population sample exhibited a more square-like form with W/L ratios similar to that of Saudi³⁵ and Turkish populations¹⁰ (Table 9). This similarity could be explained by the geographical, inter-marriages, social and ethnicity closeness of these populations. The reported W/L ratio was greater than that reported in a white population⁹ and in Asian^51,52 and even Portuguese populations⁵³. It was smaller than the one reported in Indian¹¹ and African populations⁵⁴ which exhibit an even a greater square-like tooth form with a W/L ratio of 93%(0.93), 89%(0.89) and 95%(0.95 )in an African population   , respectively, to their respected canine, lateral and central incisors (Table 9).

As for gender variation in MAT W/L ratio, this study found no difference between males and females, which was consistent with the results of the meta-analysis of Wang et al.⁴⁸ However, there were reports displaying gender variation in the MAT W/L ratio.^55,56 This discrepancy might be attributed to the inconsistency of the measuring methods among these studies, which might lead to variant results and the different ethnicities of the reports.

Dentists who work on the teeth in the jaw region, in Jordan should take into consideration the unique dimensions and characteristics of adult Jordanian patients. It is important to consider not the width from side to side but the length and the ratio of crown width to length when choosing and applying tooth sizes. In addition guidelines should address selection of size and shape identifying the level for gum placement and making accurate diagnoses for local patients⁵⁷. These guidelines would play a role in determining the dimensions for front teeth in Jordanian patients benefiting various clinical dental procedures and interdisciplinary approaches particularly those related to smile enhancement. Considering this, it is crucial for dentists working on teeth, in Jordans jaw region to have comprehensive and precise guidelines specifically tailored for the Jordanian population.

Conclusion

Based on the findings of this study it is clear that Jordanian individuals have smaller maxillary anterior teeth (MAT) compared to other ethnic groups. There were no differences, between males and females or between the right and left sides. The shape of the MAT in Jordanians was found to be squarish with width to length ratios for the canine central incisors. This pattern resembled what has been observed in Turkish populations. However it's important to acknowledge that when compared to European, Chinese, Asian and White populations the results were not directly comparable due to variations. Previous studies have also shown differences in MAT measurements, across ethnic groups highlighting how ethnicity influences tooth proportions. To gain an understanding of anterior teeth dimensions further research should involve a broader range of ethnicities and careful consideration of ethnic diversity.

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