Dear Readers,In this issue of the Journal of Applied Oral Science, two interesting studies raise an
intriguing question: is it possible to match great mechanical and biological properties in
multi-purpose materials used in dentistry?In the first study, Caldeira, et al.[1]
(2013) investigate the antimicrobial and fluoride release ability of orthodontic bonding
materials. Obviously, an efficient bonding is the primary clinical outcome expected from
such kind of materials, but in the view of biofilm accumulation generated by orthodontic
appliances, antimicrobial and enamel-protective properties also would be greatly desirable,
as discussed by the authors. Interestingly, some of the bonding agents investigated
presented satisfactory antimicrobial and fluoride release properties, but not all the
materials presented the same efficacy in both tasks (in addition to an efficient
bonding).In a second report, Guven, et al.[3] (2013)
demonstrate that calcium silicate based endodontic cements may present some degree of
toxicity over human tooth germ stem cells, when investigated in vitro simulating a
biocompatibility challenge that could occur in periapical environment. As considered in the
article, endodontic filling materials are expected to present efficient mechanical
properties (i.e. provide an effective seal and be dimensionally stable), but ideally they
should also be antimicrobial, biocompatible and pro-regenerative.Drawing a rough parallel with our current daily routines, it is interesting to notice the
coincidence between the recent proliferation of multi-purpose materials with the trend
toward the execution of multiple/simultaneous tasks. Using some cognitive and neurobiology
studies as example (an interesting reference is 'The Shallows', written by the 2011
Pulitzer Prize nominee Nicholas Carr[2], it
is becoming clear from recent studies that the execution of multiple simultaneous tasks
compromise its excellence.This interesting (and perhaps obvious) conclusion is to question if it is possible/viable
to expect outstanding/maximum mechanical and biological performance from multi-purpose
materials, and how this expectation should guide clinical decisions.In the dentistry context, it is important to remember that clinical framework of most
materials (such as orthodontic bonding and endodontic cements) application is quite
complex, and in vitro findings, while important in directing materials development, may not
necessarily represent a clinical advance or advantage. Therefore, clinical studies based on
the in vitro investigations are fundamental in determining if partially compromising
mechanical properties of a given material to add some biological properties is clinically
worthy, or if relatively simple additional procedures ('classic' biofilm control in the
case of antimicrobial orthodontic bonding) could be equally (or even more) effective in
promoting the clinical outcome expected. Alternatively, in clinical situations where a
maximal mechanical performance is not necessarily fundamental for a successful clinical
outcome, the partial exchange of mechanical to biological properties may be clinically
relevant.Therefore, it is very important to be aware of the possible advantages and disadvantages of
the booming multi-purpose materials to be used in dentistry practice, developing specific
in vitro analysis to test specific mechanical and biological aspects, in order to provide
the basis for future clinical tests to support an effective application.