Dental review; devoted to the advancement of dentistry. . 1, will gradually and with constantlydiminishing speed approach the mandrel at D. From time to time, the two mandrels held in the instrumentare brought up to the root canals of the teeth to be used as piers. When the distance between the two mandrels is equal to thedistance between the orifices of the two root canals, so that themandrels will just enter or be caught in the orifices, the parallel-ometer is locked by means of a key provided at X, Fig. 1. The mandrels are now undamped and two short studs areplaced and clamped .into the par
Dental review; devoted to the advancement of dentistry. . 1, will gradually and with constantlydiminishing speed approach the mandrel at D. From time to time, the two mandrels held in the instrumentare brought up to the root canals of the teeth to be used as piers. When the distance between the two mandrels is equal to thedistance between the orifices of the two root canals, so that themandrels will just enter or be caught in the orifices, the parallel-ometer is locked by means of a key provided at X, Fig. 1. The mandrels are now undamped and two short studs areplaced and clamped .into the parallelometer in their stead. The two heads of the parallelodrill are now spread apart ORIGIXAL COMMUNICATIONS. 109 so that they will slip over and onto the two pyramidal shapedstuds. The studs will fully engage the two spaces provided in theheads of the drill so that no variation in linear distance is pos-sible. At this time the distance between the two drill heads ofthe parallelodrill is fixed by a locking device provided at thecentre of the large Fig. Xo. 16. Fig. Xo. 17. The studs are undamped from the parallelometer and thenremoved from the drill heads. Two twist drills as much larger in diameter than the man-drels as are the platinum tubes, are now inserted into the drillheads; the parallelodrill is slipped onto the engine handpiece, thepower is turned on, and the twist drills are allowed to work theirway into the canals of the two cuspid teeth used as piers. 110 THE DENTAL REVIEW In this manner both canals are reamed out to the size re-quired and they will be parallel, each to the other. The minimumamount of tooth structure is sacrificed, and the physical integrityof the roots is never made doubtful. Fig-. 17 shows the parallelodrill with heads set at an angleof 90° for the purpose of drilling or grinding into two teeth atonce. In this position it may be used on the right lower, or leftupper jaw. The large gear will effectually hold the tongue out ofthe way. Fig. 1
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Keywords: ., bookcentury1900, bookdecade1910, bookpublis, booksubjectdentistry
