title: The mesially impacted mandibular third molar: The incidence and consequences of distal cervical caries in the mandibular second molar.
abstract: OBJECTIVE
  Distal Cervical Caries (DCC) of the mandibular second molar (Md2M) is primarily related to retained mesially impacted third molars (Md3M). Treatment of this condition indicates the removal of the Md3M and the restoration of the Md2M and, on occasions, the loss of the Md2M. The aim of this study was to determine the incidence, treatment outcomes for patients, and calculate costs related to Md2M DCC.
  
  
  METHODS
  A review of 121 patients who had Md3M removed due to Md2M DCC was undertaken to determine the treatment outcomes for patients. The number of patients affected by DCC of Md2M was calculated from the incidence of DCC (15%) in a cohort of patients requiring Md3M removal (1100) and the annual number of patients undergoing third molar surgery in England. Direct costs were calculated using NHS and independent treatment tariffs and indirect costs from Office of National Statistics (ONS).
  
  
  RESULTS
  It is estimated that 152,000 patients in England undergo third molar removal on an annual basis. Approximately 27,000 Md3M are removed annually due to DCC of the Md2M; costing £27 m to treat with additional costs of £28 m if dental implant replacement of the Md2M is included. Total cost for treating Md2M DCC: £55 m/annum.
  
  
  CONCLUSIONS
  Treating Md2M DCC and its consequences is expensive for healthcare funders such as the NHS and for patients. Md2M DCC is avoidable if patients who are at risk have prophylactic Md3M removal. This would offer potential and substantial savings in the financial cost of treating an otherwise avoidable disease.
authors.affiliation: Department of Oral Surgery, KCL Dental Institute, GSTT NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK. Electronic address: louis.mcardle@kcl.ac.uk.
authors.forename: Louis W
authors.initials: LW
authors.lastname: McArdle
authors.affiliation: Department of Oral Surgery, KCL Dental Institute, GSTT NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK.
authors.forename: Nishma
authors.initials: N
authors.lastname: Patel
authors.affiliation: Department of Oral Surgery, Institute of Dentistry, Bart's & The London School of Medicine and Dentistry, Queen Mary University of London, Turner Street, London E1 2AD, UK.
authors.forename: Judith
authors.initials: J
authors.lastname: Jones
authors.affiliation: Department of Orthodontics, KCL Dental Institute, GSTT NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK.
authors.forename: Fraser
authors.initials: F
authors.lastname: McDonald
mesh_terms: D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008334:Mandible; D008963:Molar / Q000601:surgery*; D008964:Molar, Third / Q000601:surgery; D017213:Root Caries / Q000191:economics / Q000453:epidemiology* / Q000209:etiology / Q000601:surgery; D014095:Tooth, Impacted / Q000150:complications / Q000191:economics / Q000601:surgery*
keywords: Clinical outcomes; Distal cervical caries; Third molar