Product Description
PIN Retained Resin Bonded Bridge System Perma Pin system is introduced for minimally invasive dentistry using intracoronal pin as retention aids.
Modified pin-retention technique
Unlike previously introduced pin retained prostheses which need pin hole preparation before impression procedure, our company adopted a technique to prepare pin holes before cementation of prostheses to get rid of complicated impression and laboratory procedure.
a-d : Remove occlusal surface to provide clearance, prepare groove or proximal box form if necessary and future pin hole positions are prepare with a No. ¼ round bur to expose dentin. e : Pour working cast f : Locking holes are preformed on the final prosthesis at positions correspond to marked positions for the future pin holes on the abutment teeth. g : The pin hole preparations are done through the locking holes using a 0.68 mm diameter twist drill (Yellow twist drill; Bonatec Co.) at a 1.5 -3mm depth into dentin. The depth of the pin holes can be easily established to the 3mm depth when the casting is removed from the abutment teeth. The twist drill should not be taken in and out of the preparations to check the depths because in and out movements can widen the pin hole preparations and endanger the retention of the pins. h : Before cementation of the completed RBFDP, the pin holes are properly cleaned , and the inner surfaces of the retainers are air-abraded with 50 μm alumina particle. The prepared abutment teeth surfaces are conditioned with 35% phosphoric acid and the RBFDPs are cemented using an adhesive resin cement. i : The RBFDPs are cemented so that the locking holes aligned with the pinholes of the abutment teeth. 0.6 mm diameter threaded pins (PermaPin,Bonatec Co.), dipped in resin cement were inserted into each of the pinholes through the associated locking holes, thus fixing the prosthesis to the abutment teeth.
It is advisable to fill the pinholes with adhesive resin cement, which can be done by loading an AccuDose Needle Tube and C-R syringe (Centrix Inc, Shelton, CT) before the FDP is seated on the abutment teeth (Fig.3b). After the resin cement is completely set, the threaded pins that stick out of the retainers are cut and polished to level with the retainer.
