title: Outcome of premolar extractions on Bolton's overall ratio and tooth size discrepancies in South India.
abstract: OBJECTIVE
  Attainment of ideal occlusion is often restricted by disproportionate sizes of individual teeth, which is otherwise termed as tooth size discrepancy (TSD). While extraction of teeth for orthodontic purposes is not uncommon, there is considerable resistance against this school of thought. The extraction of premolars, in particular, received considerable attention because of the potential TSD that could result following the extraction of premolars. The aim of the present study was to identify the consequence of premolar extractions on Bolton's overall ratios in South Indian population.
  
  
  METHODS
  One hundred participants were recruited into the study through purposive nonproportionate quota sampling. Pretreatment dental casts of the study participants were measured for mesiodistal tooth widths to determine Bolton's overall ratio before the hypothetical tooth extractions were performed. The hypothetical extractions were executed in four different combinations as follows: (a) Maxillary and mandibular first premolars, (b) maxillary first premolars and mandibular second premolars, (c) maxillary second premolars and mandibular first premolars, and (d) maxillary and mandibular second premolars. Bolton's overall ratios were calculated after the hypothetical tooth extractions were performed. Statistical analysis was done using the Statistical Package for the Social Sciences, version 20 software.
  
  
  RESULTS
  It was observed that extractions performed in any of the combinations followed in this study resulted in a decrease of overall Bolton's ratios. However, the discrepancy in tooth size was highest with the extraction of all first premolars, whereas least discrepancy was recorded with all second premolars extraction. It was also found that, based on the combination of teeth chosen for extraction, there was significant difference in Bolton's overall ratios between males and females.
  
  
  CONCLUSIONS
  In formulating a treatment plan involving premolar extraction, significant tooth size discrepancies could change mutually after extraction.
authors: Department of Orthodontics and Dentofacial Orthopedics, PSM College of Dental Sciences and Research, Trichur, Kerala, India.
authors: Shaji T
authors: ST
authors: Varghese
authors: Department of Orthodontics and Dentofacial Orthopedics, PSM College of Dental Sciences and Research, Trichur, Kerala, India.
authors: Purushothama R
authors: PR
authors: Yerasi
authors: Department of Orthodontics and Dentofacial Orthopedics, PSM College of Dental Sciences and Research, Trichur, Kerala, India.
authors: Lijo K
authors: LK
authors: Jose
authors: Department of Orthodontics and Dentofacial Orthopedics, PSM College of Dental Sciences and Research, Trichur, Kerala, India.
authors: T P
authors: TP
authors: Mohammed Haris
authors: Department of Orthodontics and Dentofacial Orthopedics, PSM College of Dental Sciences and Research, Trichur, Kerala, India.
authors: Tom
authors: T
authors: Mathew
authors: Department of Oral Pathology and Microbiology, MNR Dental College and Hospital, Sangareddy, Telangana, India.
authors: Kranti K R
authors: KK
authors: Ealla
keywords: Bolton analysis; extraction pattern; malocclusion; premolars; tooth size discrepancy