title: Fracture resistance and cuspal deflection of incompletely excavated teeth.
abstract: OBJECTIVE
  Incomplete excavation reduces the risk of pulpal complications, but doubts remain regarding the mechanical properties of incompletely excavated teeth. Remaining carious dentine is suspected to not sufficiently support the restoration and to reduce bond strengths between the tooth and the restoration, with effects possibly varying depending on the depth of the remaining caries lesion. This study investigated fracture resistance (FR) and cuspal deflection (CD) of premolars after leaving or removing demineralized dentine in vitro.
  
  
  METHODS
  In 48 premolars, shallow and deep artificial lesions (depths [mean ± SD] of 64 ± 18 μm and 771 ± 176 μm) were created on pulpo-axial walls of standardised mesial-distal-occlusal cavities. Demineralized dentine was either removed or left before adhesively restoring the tooth (n=12/group). Restored teeth were submitted to thermo-mechanical cycling. CD was subsequently measured at loads of 200 N and 400 N, and teeth submitted to occlusal-perpendicular loading until fracturing occurred.
  
  
  RESULTS
  FR was not significantly different between teeth with or without remaining demineralized dentine regardless of the lesion depth (p>0.30, t-test). Irrespective of the removal technique, teeth with deep lesions showed significantly decreased FR (p ≤ 0.001). In contrast, CD was significantly increased in teeth with remaining demineralized dentine compared with completely excavated teeth (p ≤ 0.05; Mann-Whitney test).
  
  
  CONCLUSIONS
  Remaining demineralized dentine did not significantly decrease the fracture resistance of premolars in vitro. Effects of increased cuspal deflection on restoration margins should be assessed. This study showed no indication that incomplete excavation increases the risk of non-pulpal complications.
  
  
  CONCLUSIONS
  Incomplete caries removal seems suitable to treat especially deep lesions. Leaving demineralized dentine does not seem to affect the fracture resistance of incompletely excavated teeth regardless of the lesion depth.
authors: Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin, Berlin, Germany. Electronic address: falk.schwendicke@charite.de.
authors: F
authors: F
authors: Schwendicke
authors: Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts Universität zu Kiel, Germany.
authors: M
authors: M
authors: Kern
authors: Department of Operative Dentistry, Periodontology and Preventive Dentistry, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Germany.
authors: H
authors: H
authors: Meyer-Lueckel
authors: Department for Conservative Dentistry and Periodontology, Christian-Albrechts Universität zu Kiel, Germany.
authors: A
authors: A
authors: Boels
authors: Department for Conservative Dentistry and Periodontology, Christian-Albrechts Universität zu Kiel, Germany.
authors: C
authors: C
authors: Doerfer
authors: Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin, Berlin, Germany.
authors: S
authors: S
authors: Paris
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001641:Bicuspid / Q000503:physiopathology; D001696:Biomechanical Phenomena; D001732:Bite Force; D003188:Composite Resins / Q000737:chemistry; D055117:Curing Lights, Dental; D001840:Dental Bonding; D003731:Dental Caries / Q000503:physiopathology / Q000628:therapy; D003737:Dental Cavity Preparation / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000503:physiopathology; D006801:Humans; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D019228:Tooth Crown / Q000503:physiopathology*; D014082:Tooth Fractures / Q000503:physiopathology*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C469607:OptiBond FL; D019279:Resin Cements; C501891:Tetric EvoCeram
keywords: Caries removal; Cuspal deflection; Fracture resistance; Partial; Residual caries