title: Salivary bacterial leakage into implant-abutment connections: preliminary results of an in vitro study.
abstract: The occurrence of bacterial leakage in the internal surface of implants, through implant-abutment interface (IAI), is one of the parameters for analyzing the fabrication quality of the connections. The aim of this in vitro study is to evaluate two different types of implant-abutment connections: the screwed connection (Group 1) and the cemented connection (Group 2), analyzing the permeability of the IAI to bacterial colonization, using human saliva as culture medium.
  
  
  
  A total of twelve implants were tested, six in each experimental group. Five healthy patients were enrolled in this study. Two milliliters of non-stimulated saliva were collected from each subject and mixed in a test tube. After 14 days of incubation of the bacteria sample in the implant fixtures, a PCR-Real Time analysis was performed. Fisher's exact test was used to compare the proportions of implant-abutment assembled structures detected with bacterial leakage. Differences in the bacterial counts of the two groups were compared using the Mann-Whitney U test. A p value < 0.05 was considered significant.
  
  
  
  The results showed a decreased stability with the screwed implant-abutment connections compared to the cemented implant-abutment connections. A mean total bacterial count of 1.2E+07 (± 0.25E+07) for Group 1 and of 7.2E+04 (± 14.4E+04) for Group 2 was found, with a high level of significance, p = .0001.
  
  
  
  Within the limitations of this study it can be concluded that bacterial species from human saliva may penetrate along the implant-abutment interface in both connections, however the cemented connection implants showed the lowest amount of bacterial colonization.
authors.affiliation: Department of Oral and Maxillofacial Sciences, "Sapienza" University of Rome, Rome, Italy. francesca.mencio@uniroma1.it.
authors.forename: F
authors.initials: F
authors.lastname: Mencio
authors.forename: P
authors.initials: P
authors.lastname: Papi
authors.forename: S
authors.initials: S
authors.lastname: Di Carlo
authors.forename: G
authors.initials: G
authors.lastname: Pompa
mesh_terms: D003470:Culture Media; D000044:Dental Abutments / Q000382:microbiology*; D059605:Dental Implant-Abutment Design; D015921:Dental Implants / Q000382:microbiology*; D003763:Dental Leakage / Q000382:microbiology*; D006801:Humans; D066298:In Vitro Techniques; D012463:Saliva / Q000382:microbiology*
chemical_list: D003470:Culture Media; D015921:Dental Implants