title: The influence of the cementation margin position on the amount of undetected cement. A prospective clinical study.
abstract: OBJECTIVE
  To evaluate the amount of undetected cement after cementation and cleaning of implant-supported restorations.
  
  
  METHODS
  Fifty three patients were treated with 53 single implant-supported metal-ceramic restorations. The subgingival location of the margin of each implant was measured with a periodontal probe mesially, distally, buccaly, and lingually(,)  resulting in 212 measurements. The data were divided into four groups: equally with tissue level (14 samples), 1 mm subgingivally (56), 2 mm (74), and 3 mm (68) below tissues contour. Metal-ceramic restorations were fabricated with occlusal openings and cemented on standard abutments with resin-reinforced glass-ionomer. After cleaning, a radiograph was taken to assess if all cement had been removed. Then the abutment/crown unit was unscrewed for evaluation. All quadrants of the specimens and peri-implant tissues were photographed and analyzed with Adobe Photoshop. Two proportions were calculated: (1) the relation between the cement remnants area and the total area of the abutment/restoration and (2) the relation between the cement remnants and the total area of implant soft tissue contour. Significance set to 0.05.
  
  
  RESULTS
  Excess on the crown groups: 1 (0.002 ± 0.001); 2 (0.024 ± 0.005); 3 (0.036 ± 0.004); 4 (0.055 ± 0.007). Undetected excess increased when the margin was located deeper subgingivally (P = 0.000), significant difference was found among all groups (P ≤ 0.05). Remnants in the soft tissue groups: 1 (0.014 ± 0.006); 2 (0.052 ± 0.011); 3 (0.057 ± 0.009); 4 (0.071 ± 0.012). The increase of the remnants was statistically reliable (P = 0.0045), significant difference was found between group 1 and 2 (P ≤ 0.05). Radiographic evaluation showed that cement remnants mesially were visible in four cases of 53 or 7.5%, and in six cases of 53 distally (11.3%).
  
  
  CONCLUSIONS
  The deeper the position of the margin, the greater amount of undetected cement was discovered. Dental radiographs should not be considered as a reliable method for cement excess evaluation.
authors.affiliation: Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania. linktomo@gmail.com
authors.forename: Tomas
authors.initials: T
authors.lastname: Linkevicius
authors.forename: Egle
authors.initials: E
authors.lastname: Vindasiute
authors.forename: Algirdas
authors.initials: A
authors.lastname: Puisys
authors.forename: Laura
authors.initials: L
authors.lastname: Linkeviciene
authors.forename: Natalja
authors.initials: N
authors.lastname: Maslova
authors.forename: Alina
authors.initials: A
authors.lastname: Puriene
mesh_terms: D000328:Adult; D000368:Aged; D002484:Cementation / Q000379:methods*; D003442:Crowns; D000044:Dental Abutments; D003738:Dental Cements; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D005260:Female; D006801:Humans; D008297:Male; D016876:Metal Ceramic Alloys; D008875:Middle Aged; D011446:Prospective Studies; D011861:Radiography, Dental
chemical_list: D003738:Dental Cements; D015921:Dental Implants; D016876:Metal Ceramic Alloys