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RELIABILITY OF PANORAMIC RADIOGRAPHS TO DETERMINE GONIAL AND FRANKFURT MANDIBULAR HORIZONTAL ANGLES IN DIFFERENT SKELETAL PATTERNS

Table 3 . Correlation coefficient between lateral and OPG for FMA angle Pearson ’ s Correlation Coefficient pValue

similar to lateral cephalograms . Oksayan et al also reported that panoramic radiograph results were as reliable as lateral cephalometric radiograph in all angle classifications and mentioned that panoramic radiography can be used as an alternative radiographic technique to detect gonial angle in orthodontic patients . Shahabi et al . 8 also concluded that panoramic radiography can be used to determine the gonial angle as accurately as lateral cephalogram . They also mentioned that in panoramic radiography the right and left gonial angles can be easily measured easily without superimposition of anatomic landmarks , which occurs frequently in lateral cephalograms . However , in a study reported by Akcam et al , 9 regression analysis showed that the forecasting capability of vertical measurements on panoramic radiographs is 11-20 % of lateral cephalograms . They stated that even though panoramic radiographs provide information on the vertical dimensions of craniofacial structures , clinicians should be cautious when predicting skeletal cephalometric parameters from panoramic radiographs , because of their lower predictability . Fischer-Brandies et al . 3 also reported that , the lateral cephalometric radiograph should be preferred in determining the gonial angle . They found gonial angle on panoramic radiograph 2.2 – 3.6 degrees less than lateral cephalograms , also these results showed significant difference between two radiographs . Shahabi et al . 8 mentioned that the discrepancy in the results could be because of the type of malocclusion and age of the samples while their study was performed in adults with Class I malocclusion . Oksayan 5 also mentioned that their study was different in that it was constructed by either adult or adolescent patients . Moreover , various studies unanimously reported that effects of the age and gender on the gonial angle was very limited . 5 , 8 , 10 Determining landmarks and discrepancies from on single OPG would reduce the patients ’ radiation doses . 11 As an illustration , Gupta and Jain 12 used OPG as a preliminary tool in diagnosing mandibular asymmetry . Puricelli 13 also suggested a method for determining mandibular measurements on panoramic radiographs . Thus , a single OPG can be reliably used for various assessments which in the past would require other forms of radiographic images .

5 . Conclusion

• Panoramic radiographs can be used as a reliable alternative to lateral cephalometric images for determination of Go and FMA .

• Panoramic radiographs can be used to predict the patients ’ growth pattern .

• Use of panoramic radiographs to determine Go and FMA can reduce patient radiation doses before or during orthodontic treatment .

Acknowledgments

The authors declare no conflict of interest related to this study . There are no conflicts of interest and no financial interests to be disclosed .

REFERENCES

1 . Xiao D , Gao H , Ren Y . Craniofacial morphological characteristics of Chinese adults with normal occlusion and different skeletal divergence . European journal of orthodontics . 2011 ; 33 ( 2 ): 198-204 . 2 . Mattila K , Altonen M , Haavikko K . Determination of the gonial angle from the orthopantomogram . The Angle orthodontist . 1977 ; 47 ( 2 ): 107-110 . 3 . Fischer-Brandies H , Fischer-Brandies E , Dielert E . [ The mandibular angle in the orthopantomogram ]. Der Radiologe . 1984 ; 24 ( 12 ): 547-549 . 4 . Larheim TA , Svanaes DB . Reproducibility of rotational panoramic radiography : mandibular linear dimensions and angles . Am J Orthod Dentofacial Orthop . 1986 ; 90 ( 1 ): 45-51 . 5 . Okşayan R , Aktan AM , Sökücü O , Haştar E , Ciftci ME . Does the panoramic radiography have the power to identify the gonial angle in orthodontics ? ScientificWorldJournal .

2012 ; 2012:219708 . 6 . Showkatbakhsh R , Castaldo MI , Jamilian A , Padricelli G , Fahimi Hanzayi M , Cappabianca S , Perillo L . Treatment effects of R-appliance and Frankel-2 in Class II division 1 malocclusions . Eur J Paediatr Dent . 2013 ; 14 ( 1 ): 17-22 . 7 . Showkatbakhsh R , Jamilian A , Alipanahi M , Perillo L . Treatment effects of R-Appliance in vertical growing patients - case series . StomaEduJ . 2014 ; 1 ( 2 ): 102-107 . 8 . Shahabi M , Ramazanzadeh BA , Mokhber N . Comparison between the external gonial angle in panoramic radiographs and lateral cephalograms of adult patients with Class I malocclusion . J Oral Sci . 2009 ; 51 ( 3 ): 425-429 . 9 . Akcam MO , Altiok T , Ozdiler E . Panoramic radiographs : a tool for investigating skeletal pattern . Am J Orthod Dentofacial Orthop . 2003 ; 123 ( 2 ): 175-181 .