Microbiology of Peri-implant Tissues in Cone Morse Connection: A Randomized Controlled Study

Objectives: Implants with a cone morse connection show a lower incidence of perimplant bone loss and a higher stability of perimplant soft tissue, if compared with the traditional systems.
Even if the reasons of this behaviour are not clear, many evidences suggest that the microbial penetration could be better prevented by the cone morse connection, creating a minimal room around the abutment.
The aim of this study was to evaluate the colonisation of bacteria around cone morse connection implants ( Implacil, De Bortoli, Brazil) and to compare these data with those from implants with traditional connection.
Methods:
The study was designed as a split-mouth, randomized, controlled study.In each of 13 patients (5 male, 8 female, mean age 61±9.4), a single operator (GT) placed a cone morse and a traditional implant.
After the a period of 6 months after the final restoration with ceramic or zirconia crowns, a sample of subgingival microbiota was collected.

Inclusion criteria:
No bleeding on probe
No systemic or topical antibiotic therapy in the last 6 months
No radiological signs of perimplantitis
Last professional hygiene 4 months before the sampling
Good general health and absence of assumption of drugs

Microbiological evaluation
All samples were collected using paper swabs by the same operator (AS); the analysis were conducted using a PCR test (Biomolecular Diagnostic, Firenze, Italia).
Statistical analysis
Mann-Whitney test was used; p< 0.05 was considered statistically significant.

Results: Data are summarized in table 1For the total bacteria count, the difference between the 2 group was statistically significant(U-value=37; Z=2.41; p=0.01596)
Also in the subgroup of pathogens, the difference was statistically significant(U-value=30; Z-score= 2.76923; p=0.0056).
Conclusions: The cone morse connection is a valid defence to bacteria invasion of the perimplant soft tissues; these data can explain the lower incidence of perimplatitis of these implants. Studies with higher numberof patients are recommended.
6923; p=0.0056).