COMPARISON OF ABOUL-AZM AND FOUDA'S APPROACH OF MIXED DENTITION ANALYSIS WITH MOYERS TECHNIQUE

with Moyers technique. Esmaons of the widths of theunerupted permanent canines, ﬁrst and second premolars were performed for maxillary and mandibular arches using Aboul-Azm and Fouda's and Moyers predicon methods. The predicted values were then compared with the measurements of the actual teeth on 224 study models of males and females. The study was conducted from October to December 2021. The study was conducted on 112 male and female samples each. For males, stascally signiﬁcant underesmaon were found for Aboul-Azm and Fouda's method in both arches whereas Moyers method showed beer accuracy in males. In females Moyers method showed a signiﬁcant overesmaon. In the total sample the Moyers method showed accuracy for maxillary arch whereas Aboul-Azm and Fouda's method was more accurate for the mandibular arch. Moyers method showed a good accuracy in the maxillary arch while in the mandibular arch Aboul-Azm and Fouda's methodwas moreaccurate.


Introduc on
The predic on of mesiodistal widths of unerupted canines and premolars are an important aspect of analysis of the developing permanent den on. Various radiographic as well as non radiographic methods have been tested and researched to predict the width of these teeth. The Moyers mixed den on analysis is a universally accepted technique. Whereas Aboul-Azm and Fouda's approach of mixed den on analysis is a concept that derives the measurement from equa on based on the bucco lingual width of the permanent first molars. It does not require any table for the predic on.

Objec ve
The present study compares the Aboul-Azm and Fouda's approach of mixed den on analysis with Moyers technique.

Methodology
Es ma ons of the widths of theunerupted permanent canines, first and second premolars were performed for maxillary and mandibular arches using Aboul-Azm and Fouda's and Moyers predic on methods. The predicted values were then compared with the measurements of the actual teeth on 224 study models of males and females. The study was conducted from October to December 2021.

Result
The study was conducted on 112 male and female samples each. For males, sta s cally significant underes ma on were found for Aboul-Azm and Fouda's method in both arches whereas Moyers method showed be er accuracy in males. In females Moyers method showed a significant overes ma on. In the total sample the Moyers method showed accuracy for maxillary arch whereas Aboul-Azm and Fouda's method was more accurate for the mandibular arch.

Conclusion
Moyers method showed a good accuracy in the maxillary arch while in the mandibular arch Aboul-Azm and Fouda's methodwas moreaccurate.

INTRODUCTION
Mixed den on period is the period that commences with the erup on of first permanent molar and ends with complete replacement of the primary teeth. It coincides with the rapid growth of cranio facial skeleton and an early iden fica on and interven on of an cipated orthodon c 1 problems in children proves to be beneficial. Mixed den on model analysis calculates the difference between the amount of space present in the dental arch and the amount of tooth material that can be accommodated in 2,3 perfect alignment. Various methods have been researched and applied for analysis in the mixed den on period which incorporate the use of models, radiographs or a combina on 4 of both. Moyers mixed den on analysis is a universally accepted tool,developed at the University of Michigan based on the odontometric data of American White subjects of Northwestern European descent. It consists of a predic on table which is based on a correla on between the sum of the mesio-distal width of mandibular incisors that predict the combined measurementof unerupted mandibular and 2,3,5 maxillary permanent canine and premolar. 6 Abuol-Azm and Fouda have documented another approach of mixed den on analysis. This predicts the combined width of permanent canines and premolars based onthe buccolingual measurements of the permanent first molars using equa ons for the upper and lower den on. Using this 7 method Fouda conducted a compara ve analysis and reported an accuracy of 75%.Clinically this technique requires shorter me with no requirement for a probability chart. The present study therefore compared the mixed den on analysis using the Aboul-Azm and Fouda's approach and Moyers technique.

METHODOLOGY
A cross sec onal clinical study was under taken using pretreatment orthodon c study casts in the Department of Pedodon cs at Kan pur Dental College from October to December 2021. The study was started a er approval by the Ins tu onal Review Commi ee (Ref No.22/021). Pretreatment maxillary and mandibular dental casts of pa ents aged between 14 to 25 years with fully erupted permanent teeth atleast upto the first permanent molars were used. The sample size was calculated by the formula- . The inclusion criteria were good quality pre-orthodon c treatment casts free from distor ons, dental caries and interproximal restora ons, having fully erupted mandibular incisors, canines, premolars and first permanent molars. The exclusion criteria were study casts of pa ents with a former history of orthodon c treatment, missing or supernumerary teeth, significant teeth wear, hypoplas c teeth and abnormally sized or shaped teeth. The teeth were measured by a digital vernier caliper set to read to the nearest 0.01 mm and all measurements were made by a single inves gator. From each model, the following were recorded: · Mesiodistal Diameter (MDD) for all permanent mandibular incisors, all permanent canines (C)and first and second premolars (P and P respec vely) in each 1 2 quadrant. The measurements were made perpendicular to the long axis of tooth by entering the caliper beak from interproximal area from occlusal side.
· Buccolingual Diameter (BLD) of all permanent first molars in each quadrant , the maximal distance between the buccal and lingual surface perpendicular to the mesio-distal diameter of tooth and parallel to the occlusal plane.
Two different non-radiographic techniques for mixed den on analysis were used in the study. In Moyers Method the sum of the mesiodistal measurements four permanent mandibular incisors were used to predict the combined size of the permanent unerupted canines and premolars for both th 2 quadrants using Moyers probability table at 75 percen le. 6 In Aboul-Azm and Fouda'smethod , the buccolingual measurements of the permanent first molars of each quadrant was used in equa on to predict the combined size of permanent canine and premolars for each quadrant. In the maxillary arch, the combined widths of the canine and bicuspids on one side is equal to the bucco-lingual width of the first permanent molar mul plied by 2 and minus 1 from the total value obtained. Whereas in the mandibular arch, the mesiodistal widths of canine and bicuspids on one side equal the buccolingual width of the first permanent molar on that side mul plied by 2.
The sta s cal analysis of the data was carried out using Sta s cal Package for Social Sciences (SPSS) for Windows version 20(SPSS Inc., Chicago, III.,USA). The sta s cal analyses performed were: descrip ve sta s cs including the mean and standard devia on. Gender dimorphism was assessed using Independent sample t-test and paired sample t-test was used to compare the actual and predicted values. The p-value of ≤0.05 was considered to be significant.

RESULTS
The sample consisted of 224 dental casts (112 males and 112 females). The descrip ve sta s cs of sum of actual mesiodistal widths of permanent canines and premolars in all quadrants, sum of permanent mandibular incisors and buccolingual widths of all permanent first molars is depicted in table 1.     Table 3 shows the comparison of the actual value with the predicted values using the two methods in the maxillary and mandibular arches of males and females using paired t-test.
In the maxillary arch the Aboul-Azm and Fouda's method showed a significant underes ma on whereas in the mandibular arch the Moyers method depicted an overes ma on. The remaining measures were accurate. In the males the Aboul-Azam and Fouda's method in both the arches showed an underes ma on while Moyers method was more accurate to actual value. While in the females the accuracy of Aboul-Azam and Fouda's method was more be erfor mandibular arch while it showed an under es ma on in maxillary arch. The Moyers method showed an overes ma on in the mandibular arch in females. When the two methods were compared, there was a sta s cally significant difference between the two methods, the Moyers method showed a higher calculated values of permanent canines and premolars in both the genders as well as in both the arches. (Table 4)

DISCUSSION
The primary den on paves the future of the permanent den on and it has been found that the presence of crowding in the primary den on increases the probability 9 ofmalalignment in the permanent den on. The arch length has a tendency to decrease during the transi on from 10 mixed to permanent den on. Predic ng the size of unerupted canines and premolars during the mixed den on period is a cri cal factor because an early correct assessment of these lead to be er management of tooth 11,12 size/ arch length discrepancies. The basic principles for mixed den on model analysis are that it should be simple, fast, prac cal, precise and 12,13 applicable in both the arches. The mixed den on analysis methods use either of the following: radiographs, 10 predic on tables or a combina on of both the methods. The mesiodistal (MD) widths of tooth was first es mated by 14 Black, who proposed tables based on average widths. Over the years, many methods have been developed, however no method of mixed den on analysis has 100% accuracy and 12 may overes mate or underes mate the predicted widths. One of the most widely used methods is the Moyers' analysis where a probability table predicts the amount of space required to align the permanent canines and premolars by u lizing the sum of the width of the four 15 mandibular permanent incisors. Most of the other non radiographic techniques also u lize the measurements of permanent lower incisors with or without molar dimensions for the predic on. Few researchers have suggested that using only the mesiodistal width of mandibular incisors is not the best predictor for the 12 width of unerupted permanent canines and premolars. However in a compara ve study among seven methods of 1 mixed den on analysis conducted by Kondapaka et al , Moyers method was more reliable in maxillary arch in both genders. Many methods have u lized the dimensions of the permanent molars for predic on without requiring 6,7,10 predic on charts. 6 AboulAzm and Fouda formulated a method that makes predic ons based on equa ons that need the measurements of only the bucco-lingual dimension of the permanent first molars in each quadrant. The benefit of this technique is that the dimension can be measured clinically as well and it requires minimum me, does not need a probability chart and can also be done before the erup on of the lateral incisors. The use of permanent first molars has an added advantage that they erupt early in the mixed den on 13 period, are easy to measure showing li le variability in size. 7 Fouda MA proved the validity of Aboul-Azmand Foudamethod in Angle's class I cases to be 75%.The more frequently used Moyers method was therefore compared with the less frequently used but simpler approach given by Aboul-Azm and Fouda, in the present study. This study u lized 224 upper and lower dental casts, of 112 male and female samples each, which were evaluated together as well as separately. The results indicate a significant sexual dimorphism in the actual widths, the males having a larger mesiodistal and buccolingual tooth widths than females which was in consensus with other 9,10,12,13,16,17 studies.
Many authors are in disagreement with no 5,18,19 difference seen among males and females.
The predicted tooth size can show either an overes ma on or an underes ma on. When the predic on is under es mated, it can lead to inadequate space and crowding of the permanent teeth, on the other hand an overes ma on 7 may result in unnecessary extrac on. An overes ma on up to 1 mm beyond the actual value do not affect the decision 12 of extrac on or non-extrac on. 2 In the present study, the Moyers method showed more accuracy to actual value in the Maxillary arch in the en re sample while more accurate results were given by the 6 Aboul-El-Azam and Fouda's method in the mandibular arch. Varia on in the accuracy while comparing the predicted values using different techniques have showed different accuracy for the maxillary and mandibular arch in different 12 1 studies. Kondakapa et al reported an over-predic on of 89.16% and 75.83% of cases in maxillary and mandibular arch respec vely. Similar overes ma ons with Moyers predic on at 75% probability have been reported by many 3,5,12,20,21 authors. The predic ons in this study was also analyzed individually for both the genders. In the males the Aboul-Azam and Fouda's method in both the upper and lower arch showed an under es ma on whereas Moyers method was more 9 accurate to the actual value. Mahmoud et al found the Moyers method in males to be accurate in the upper arch with less accuracy noted in the lower arch.
In the females the accuracy of Aboul-Azam and Fouda's method was more for mandibular arch while it showed an underes ma on in maxillary arch. The findings of 7 Fouda's study are in agreement to this study, where, the predicted widths of the tooth material were close to the actual widths in the lower arch. Moyers method however overes mated the values in the lower arch in females, which 1 18 is in consensus to the study by Kondapakaet al . Mishra  al reported overes ma on in both arches in males and in the mandible in females whose finding is in agreement with 22 the present study. Shrestha et al reported that in the Newar community of Nepal, the Moyers probability table can be used to predict combined mesiodistal width at 75% level for mandible in male which agrees with our study while they state a higher probability levels for other sites.

CONCLUSION
It was observed in the present study that both the methods of mixed den on analysis have certain deficiencies; however the applicability of Moyers method was accurate for upper arch whereas for mandibular arch,Aboul-Azm and Fouda's method showed be er accuracy. It can be concluded that for mixed den on analysis separate techniques can be used for the upper and lower arch and this can be further studied.

LIMITATIONS OF THE STUDY
The study compared two methods of mixed den on analysis, further studies can be conducted to compare the Aboul-Azm and Fouda's method with other commonly used techniques.