Influence of different lubricants on the retentive force of LOCATOR(®) attachments - an in vitro pilot study.
OBJECTIVE
The aim of this in vitro pilot study was to evaluate the influence of an artificial saliva (AS) lubricant on the retentive force of a stud-type attachment (LOCATOR(®) ) for implant overdentures (IODs).


METHODS
Twenty custom-made models simulating a two-IOD with parallel implant situation were fabricated using LOCATOR(®) attachments. The in vitro testing was carried out with an Instron(®) universal testing machine for a total of 10,000 insertion-removal cycles, for each model, in two different aqueous test mediums (Group 1: 0.9% sodium chloride solution (NaCl), n = 10; Group 2: AS, n = 10). Changes in the mean retentive force (F) were plotted against the cycle numbers #10, #100, #1000, #5000, and #10,000. Mixed regression models were applied for statistical analyses.


RESULTS
A mixed regression (not considering interactions) predicted, compared to cycle #10, higher retentive forces at cycles #100 (P < 0.0001), #1000 (P = 0.017), similar forces at #5000 (P = 0.277), and lower forces at #10,000 (P = 0.012); there was no overall effect of the medium (P = 0.159). A second statistical model, employing the interaction term "cycle##medium", confirmed similarly the effect. Although the interaction term was significant at cycle #100 (p = 0.045), there was no significant difference between the two groups (P = 0.140).


CONCLUSIONS
In this in vitro pilot experiment, there was no difference in mean retentive forces of the LOCATOR(®) attachments when tested with either 0.9% NaCl or a Glandosane(®) -like artificial saliva lubricant. A larger scale study may still confirm the superiority of either lubricant for quasiclinical bench experiments.
Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland.
Murali
http://orcid.org/0000-0003-3365-576X
M
Srinivasan
Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland.|Division of Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
Martin
M
Schimmel
Unit of Oral and Maxillofacial Implantology, Tsurumi University, Yokohama, Japan.
Mariko
M
Kobayashi
Division of Bone Diseases, Department of Rehabilitation and Geriatrics, Geneva University Hospital, Geneva, Switzerland.
Isabelle
I
Badoud
Division of Bone Diseases, Department of Rehabilitation and Geriatrics, Geneva University Hospital, Geneva, Switzerland.
Patrick
P
Ammann
Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals of Geneva, Thônex, Switzerland.
François R
FR
Herrmann
Division of Gerodontology and Removable Prosthodontics, University Clinics of Dental Medicine, University of Geneva, Geneva, Switzerland.|Division of Geriatrics, Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals of Geneva, Thônex, Switzerland.
Frauke
F
Müller
D019094:Dental Prosthesis, Implant-Supported; D003834:Denture Precision Attachment; D003781:Denture Retention; D003828:Denture, Overlay; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D010865:Pilot Projects; D012464:Saliva, Artificial
D012464:Saliva, Artificial
LOCATOR® attachments; artificial saliva; dislodging cycles; in vitro testing; overdentures; retentive force