title: ZACD: A Retrograde Panoramic Analysis among Indian Population with New System of Classification.
abstract: BACKGROUND
  Zygomatic Air Cell Defect (ZACD) has been considered as a normal radiographic variant with a spare knowledge. This should be judged before any surgical procedure of the temporal region as lack of which can lead to infections of cranium and may other complications.
  
  
  OBJECTIVE
  The present study was undertaken to estimate the prevalence and characteristics of ZACD and to propose a classification for the same using digital panoramic radiography.
  
  
  METHODS
  A total of 6825 digital panoramic radiographs were evaluated retrospectively of subjects aged between 4-90 years from both genders. The radiographs were evaluated by 4 (four) oral radiologists and the ZACD was recorded only when the decision was indisputable.
  
  
  RESULTS
  Out of 6825 digital panoramic radiographs evaluated ZACD was noticed in 133 subjects with an overall prevalence of 1.94%. A male predilection was noted in the present study with the maximum prevalence during the second, third and fourth decade of life and as the age increases its prevalence decreases. Most commonly it was found to be unilateral and the unilocular presentation being more common.
  
  
  CONCLUSIONS
  Most of the finding of the present study is in acceptance with those conducted previously, but some of the finding contradicts those in the previous ones. It can be because of low sample size of the previous studies. Moreover this study gives a new system to classify these defects to help diagnose the nature of the defect.
authors.affiliation: Senior Lecturer, Department of Oral Medicine & Radiology, Daswani Dental College & Research Centre , Kota, Rajasthan, India .
authors.forename: Karandeep Singh
authors.initials: KS
authors.lastname: Arora
authors.affiliation: Senior Lecturer, Department of Oral & Maxillofacial Pathology, B.R.S. Dental College & General Hospital , Panchkula, Haryana, India .
authors.forename: Prabhpreet
authors.initials: P
authors.lastname: Kaur
authors.affiliation: Private Practitioner, American Dental Education Association, Omicron Kappa Upsilon - Honor Dental Society - Lamda Lamda Chapter , Texas .
authors.forename: Kirandeep
authors.initials: K
authors.lastname: Kaur
keywords: Articular eminence; Panoramic radiography; Pneumatization; Zygomatic air cell defect