The influence of saliva pH value on the retention and durability of bar-clip attachments.
OBJECTIVE
The aim of this study was to compare the durability and retention of 4 types of attachments placed over computer aided design/computer aided manufacturing (CAD/CAM) titanium bars when subjected to different pH conditions.


METHODS
Four commercially available attachments were investigated: Hader Yellow, Hader Red, Ackerman Gold and Ackerman Stainless Steel. These attachments and Ackerman CAD/CAM titanium bars were placed in 2 vessels containing different artificial saliva solutions (pH 7/pH 4) at 37℃ for one month to simulate corrosion conditions, and they were then subjected to mechanical testing (5400 cycles of insertion and removal).


RESULTS
The results revealed that there were significant differences in the average values of insertion/removal force due to the pH (F (1, 24)=9.207, P<.05) and the type of attachment (F (3, 24)=11.742, P<.05).


CONCLUSIONS
More acidic pH values were found to have a negative influence on the retention capacity of the attachments.
Department of Oral Rehabilitation, Instituto Superior de Ciencias da Saude - Norte, Gandra, Portugal.
Antonio Sergio
AS
Silva
Department of Oral Rehabilitation, Instituto Superior de Ciencias da Saude - Norte, Gandra, Portugal.
Carlos
C
Aroso
Industrial Engineer, Chairman of Idearum, Enginyeria i Innovació de Producte, Igualada, Barcelona, Spain.
Raul
R
Ustrell
Department of Production and Systems Engineering, University of Minho (UM), Braga, Portugal.
Ana Cristina
AC
Braga
Department of Oral Rehabilitation, Instituto Superior de Ciencias da Saude - Norte, Gandra, Portugal.
Jose Manuel
JM
Mendes
Department of Rehabilitation and Maxillofacial Prostheses, Faculty of Odontology, University of Barcelona, Barcelona, Spain.
Tomas
T
Escuin
Attachments; Corrosion; Dental implants; Edentulous patients; Overdentures