title: Comparison of 7 luting protocols and their effect on the retention and marginal leakage of a cement-retained dental implant restoration.
abstract: OBJECTIVE
  To determine the cement bond strength and marginal leakage of castings cemented to implant abutments.
  
  
  METHODS
  Fifty-six titanium abutments and castings were divided into 7 groups (n=8), 1 for each cement. Castings were cemented to abutments using 1 of 3 resin-based cements (RES, RES-B, and RES-B-P), a resin-modified glass ionomer (GI), a polycarboxylate cement (PCB), an acrylic urethane cement (UDM), or a zinc phosphate cement (ZP). Specimens were placed in 100% humidity at 37 degrees C for 24 hours. Specimens were subjected to compressive load cycling followed by thermal cycling; they were then immersed for 24 hours in 0.5% basic fuchsin. Castings were removed with an Instron universal testing machine with a crosshead speed of 0.125 cm/min. Leakage was visually graded from 0 (no leakage) to 2 (leakage extended beyond the lower half of the internal surface of the casting). Failure load (FL) was analyzed with analysis of variance and Scheffe's test (alpha = .05). Chi-square was used to analyze leakage (alpha = .05).
  
  
  RESULTS
  Cements were categorized by FL into 4 statistically unique groups: (1) RES-B-P (351 N) and GI (337 N); (2) ZP (245 N) and RES-B (241 N); (3) PCB (107 N); and (4) RES (63 N) and UDM (55 N). Leakage was greater for the PCB group than for the other groups (7 of 8 specimens demonstrated leakage; P < .01). Three ZP specimens demonstrated leakage. UDM and RES each had 1 specimen with leakage. RES-B-P, RES-B, and GI showed no leakage.
  
  
  CONCLUSIONS
  Luting agents designated by the manufacturer as provisional cements demonstrated lower resistance to removal, regardless of material type. Luting agents described by manufacturers as "permanent" differed in resistance, with resin cements being most resistant, followed by zinc phosphate and polycarboxylate cements. Provisional cements demonstrated leakage comparable to higher-strength materials.
authors.affiliation: Dental Department, Chang-Gung Memorial Hospital, Keelung, Taiwan, Republic of China. philipck-lin@msn.com
authors.forename: Yu-Hwa
authors.initials: YH
authors.lastname: Pan
authors.forename: Lance C
authors.initials: LC
authors.lastname: Ramp
authors.forename: Ching-Kai
authors.initials: CK
authors.lastname: Lin
authors.forename: Perng-Ru
authors.initials: PR
authors.lastname: Liu
mesh_terms: D003738:Dental Cements / Q000737:chemistry*; D015921:Dental Implants; D003763:Dental Leakage; D017268:Dental Prosthesis Retention / Q000379:methods*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D006358:Hot Temperature / Q000009:adverse effects; D013718:Tensile Strength; D016474:Weight-Bearing
chemical_list: D003738:Dental Cements; D015921:Dental Implants