In this report, we propose a new application of light-curing dental resins for mounting base of electrodes or microdialysis probes in chronic experiments. This material allows direct bonding to the cranium.
Step 1. Preparation of probe implantation
Step 2. Stereotaxic positioning
Step 3. Pretreatment of the cranial surface
(The similar procedure for “direct filling restoration” of the dental product shall be employed.)
Step 4. Mounting composite resin
Clean the surgical area, apply antibiotic (Gentamicin ointment), and remove the animal from the stereotaxic flame. Then, keep the animal in a thermo-controlled chamber (temperature = 33-35° C) for post-anesthetic recovery.
As shown in the video, no abnormal behavior was observed in any of the animals on the next day after the surgery.
Compared to the application of conventional self curing acrylic resins, the introduced technique has several important advantages:
1. Direct bonding:
Self curing acrylic can be attached to the bone for a while but it does not adhere to the bone. Therefore, anchorage screws are required to fix a mounting base (See Figure 2A). In contrast, light curing resin can bond to the bone directly so screws are not required (Figure 2B). Therefore, size of mounting base can be reduced considerably. In addition, light curing resins also adheres to some metals, if you used "metal primer" with it. This feature of bonding to variable materials allows us a wide range of application.
Figure 2 shows an implantation using conventional self curing acrylics (in 2A) and an implantation using light curing adhesive resins (in 2B). In 2A, the anchor screw is used to fix the mounting base. In 2B, size of mounting base can be reduced considerably due to the fact that light curing resin adhere to the cranium and such screws are not required.
Figure 2 Please click here to view a larger version of this figure.
2. Easy to handle:
Conventional resin's processing time window is relatively short, within few minutes. It has a high fluidity and it is not easy to handle at first. However, once chemical reaction started, reaction is accelerated by exothermal heat and resins become harder in short time. The processing time windows for light curing resin are significantly wider and adjustable. Basically, resins keep constant elasticity from the beginning to the moment when it is light cured.
3. Reaction does not generate heat:
Curing reaction of self-curing resin is exothermal. When the mounting base is thick, this heat accumulates and may damage the tissue. Reaction of light curing resin does not generate heat and the material is biocompatible.
4. Hand made LED light:
Cost of the material and special equipment like light unit can be a problem. In Figure 3, we introduce a hand made LED light unit which does not cost much. This hand-made light curing unit may be used as substitutes for expensive commercial unit.
Figure 3A shows a circuit diagram of light unit. Figure 3B shows three LEDs glued parallel to each other, and inserted into the holder of a white board marker.
Figure 3 – Circuit diagram (in A) and photograph (in B) of a hand-made light unit. Please click here to view a larger version of this figure.
This technique is applicable to chronic implantations of electrodes or microdialysis probe in other experimental animals such as fish, mouse, rabbit, cat and monkey.
The authors have nothing to disclose.
We thank our colleagues in RIKEN-BSI for their kindly supports and fruitful advices during this work. I would like to express my sincere appreciation to Professor Shigemi Mori, Professor G bor Juh sz, Drs. Kiyoji Matsuyama, Katalin A K kesi and rp d Dobolyi who advised me to study microdialysis method during the graduate course at the Graduate University for Advanced Studies, Japan. Finally, we thank Mr. Chris Sarnecky and Dr. Akitsugu Takasu for their supports in video recording.
Material Name | Tipo | Company | Catalogue Number | Comment |
---|---|---|---|---|
Bengalese finches | Animal | Two adult male , Body weight: 14.2 g and 14.8 g | ||
Microdialysis probe | Tool | EICOM | total weight of probe, guide cannula, cap nut and dental adhesive resin: 0.65 to 0.78 g. | |
Light-cured dental adhesive resin system | Kuraray Medical Inc | +Light cured composite resin (CLEARFIL AP-X). +Dual-cure dental adhesive system with the self-etching primer and bonding agent (CLEARFIL Liner Bond IIΣ). | ||
Surgical instruments | Stereotaxic frame, surgical microscope, thermal controlled surgical pad and thermal controlled recovery chamber. Plain plugger for handling composite resin. Microspatula or sharp curette to ablate periosteum and muscles. Injection syringe and needle (30G) for inducing anesthesia. Small scissors. Fine forceps for making small craniotomy. | |||
Light-unit | Rolence Enterprise Inc | Ultra-Lite 500E | ||
Microscope | Konan Medical | KOM300 | with C-mount adaptor | |
3- CCD camera | Tool | Hitachi | HV-D30 |
Photograph 1A shows microdialysis probe (a), a cap nut (b) and a guide cannula (c). In this photo, the guide cannula is surrounded by dental resin which adheres to the skull directly. Photo B shows a bird during drug perfusion. On the top of the head, there is a microdialysis probe that is connected to a fine tefron tube. Scale bars = 1 cm for A and 2 cm for B, respectively.
Figure 1 – Photographs of a microdialysis probe (A) and a bird during drug perfusion (B)