title: Effects of 3-dimensional conformal or intensity-modulated radiotherapy on dental pulp sensitivity during and after the treatment of oral or oropharyngeal malignancies.
abstract: BACKGROUND
  Radiation therapy (RT) of malignant tumors in the head and neck area may have damaging effects on surrounding tissues. The aim of this investigation was to evaluate the effects of RT delivered by 3-dimensional conformal radiotherapy (3D-RT) or intensity-modulated radiotherapy (IMRT) on dental pulp sensitivity.
  
  
  METHODS
  Twenty patients with oral or oropharyngeal cancer receiving RT with 3D-RT or IMRT underwent cold thermal pulp sensitivity testing (PST) of 2 teeth each at 4 time points: before RT (TP1), the beginning of RT with doses between 30 and 35 Gy (TP2), the end of RT with doses between 60 and 70 Gy (TP3), and 4 to 5 months after the start of RT (TP4).
  
  
  RESULTS
  All 40 teeth showed positive responses to PST at TP1 (100%) and 9 at TP2 (22.5%; 3/16 [18.8%] for 3D-RT and 6/24 [25.0%] for IMRT). No tooth responded to PST at TP3 and TP4 (0%). A statistically significant difference existed in the number of positive pulp responses between different time points (TP1 through TP4) for all patients receiving RT (P ≤ .05), IMRT (P ≤ .05), and 3D-RT (P ≤ .05). No statistically significant differences in positive sensitivity responses were found between 3D-RT and IMRT at any time point (TP1, TP3, TP4, P = 1.0; TP2, P = .74). A statistically significant correlation existed between the location of the tumor and PST at TP2 for IMRT (P ≤ .05) but not for 3D-RT (P = .14).
  
  
  CONCLUSIONS
  RT decreased the number of teeth responding to PST after doses greater than 30 to 35 Gy. The type of RT (3D-RT or IMRT) had no influence on the pulp responses to PST after the conclusion of RT.
authors.affiliation: Discipline of Endodontics, Department of Esthetic Dentistry, School of Dentistry, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Simony H
authors.initials: SH
authors.lastname: Kataoka
authors.forename: Frank C
authors.initials: FC
authors.lastname: Setzer
authors.forename: Eduardo R
authors.initials: ER
authors.lastname: Fregnani
authors.forename: Oscar F
authors.initials: OF
authors.lastname: Pessoa
authors.forename: Eudes
authors.initials: E
authors.lastname: Gondim
authors.forename: Celso L
authors.initials: CL
authors.lastname: Caldeira
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003080:Cold Temperature; D003782:Dental Pulp / Q000528:radiation effects*; D003791:Dental Pulp Test / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000532:radiotherapy*; D009959:Oropharyngeal Neoplasms / Q000532:radiotherapy*; D016300:Radiography, Bitewing; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D011882:Radiotherapy, High-Energy; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*