as shown in fig1 , an endodontic tool or instrument in accordance with the present invention is generally indicated at 10 , and includes a handle 12 , a detachable retainer 14 , and an applicator indicated at 16 . fig1 shows the instrument with its components , namely , handle 12 , retainer 14 , and applicator 16 , fully assembled . the instrument as shown is ready for a coolant to be applied to the applicator so that a doctor may position the applicator tip against a tooth or teeth to determine which is the situs of a patient &# 39 ; s pain . the actual assembly , and a description of the components of the instrument will now be described . the holder of instrument 12 is dimensioned with a length for being comfortably held by a doctor , and includes a neck indicated at 12 a and a wider or flared end 12 b which further includes an extension 12 c provided for fracture testing of a tooth . it will be noted that holder 12 also includes a hollow portion extending from its front inwardly from the holder proper , for receiving retainer 14 , in a manner to be described . as shown in fig2 , retainer 14 is an elongate member , which may be dimensioned generally in the range of about 4 - 5 inches , which includes a central notched portion or neck 18 and opposed aligned sections or arms 20 and 22 , each of which extend to an associated angled or contra angled member 24 and 26 , respectively . arms 20 and 22 include projections 20 a and 22 a respectively , dimensioned to limit the extent to which arms 20 and 22 may be folded inwardly toward or against one another , when the arms are inserted into the open end of holder 12 . arm 20 further includes a retention tab 20 b and arm 22 includes a retention tab 22 b , each of these are dimensioned for insertion and retention into corresponding , opposed apertures 15 and 17 , respectively , extending from a hollow bore or region 13 of holder 12 , when arms 20 and 22 are pivoted or folded over one another about neck 18 . attention is now directed to the construction of angled portions 24 and 26 . as shown in fig2 each arm is inclined at an angle a , of about 35 degrees , or in the range generally of about 25 - 50 degrees , relative to the long axis , shown in dashed lines , of arms 20 and 22 . this inclination facilitates the doctor &# 39 ; s ability to see exactly where the applicator tip is positioned when it is inserted near the posterior teeth in a patient &# 39 ; s mouth . each angled portion is dimensioned similarly overall , but there are important differences . angled portion 26 includes extensions or pin 26 a and post 26 b , dimensioned for reception into corresponding aligned apertures 24 a and 24 b , respectively , in angled portion 24 . a stop or limit member is shown at 24 c , which is to provide a guide as to the extent of insertion of applicator 16 . the retainer may be fabricated or molded of a semi transparent thermoplastic resin . rounding out a description of applicator 16 , which is the final component , attention is directed to fig5 . as shown , applicator 16 is a small block of resilient , absorbent material , which may be formed as an open cell foam insert indicated at 28 , and includes a generally rounded or curved or convex end or tip 28 a and an inwardly curved opposed end 28 b . the applicator may be dimensioned about ½ to 1 inch in length and ¼ to ½ of an inch in width , and about ⅛ to 3 / 16 of an inch in thickness . the foam is flexible and adapted to be saturated with a conventionally available coolant ( subsequent to being held in the retainer ). it is readily mounted and firmly gripped by the retainer , which in turn is received in the handle . the assembly of the foam applicator and retainer will now be described . the instrument has been designed to provide controlled cold testing of multiple teeth , and its assembly is simple . the applicator and retainer are not contemplated as being reusable , although the holder may be readily sanitized in an autoclave process , for repeated use . initially , it is necessary to insert the retainer into the holder , and the steps for assembly are shown in fig2 , 2 a , 3 and 6 - 9 . the doctor selects the retainer , such as that shown in fig2 , and then bends or folds one portion over the other ; for example , as shown in fig2 a , where arm 22 has been folded toward and over arm 20 , about a fold axis indicated at neck 18 . pivoting about neck 18 continues until a substantially complete fold is provided , as shown in fig3 . in this orientation , retainer 14 is now positioned for detachable insertion into holder 12 , ( see fig8 ) and may be fully inserted until the retainer is in a secure position , with retention tabs 20 b and 22 b snapped into reception in apertures 15 and 17 , respectively . fig4 shows arms 20 and 22 as they are inserted into the hollow portion , prior to full insertion , when retention tabs 20 b and 22 b will be inserted in apertures 15 and 17 , respectively . angled portions 24 and 26 are shown slightly spread apart , as they may be , during insertion , but once fully inserted may be positioned more adjacent one another . as shown in fig9 the doctor now spreads apart the arms , in particular angled portions 24 and 26 of retainer 14 , and inserts a single foam applicator 16 about half way into the assembly , as shown in fig6 and 9 . once the block of foam applicator is inserted , the angled arms are squeezed so that pin 26 a and post 26 b penetrate the foam and angled arms 24 and 26 engage and firmly grip the foam to secure it n place , as shown in fig7 . a tip portion of the foam extends outwardly from the retainer , as shown in fig7 . the doctor should gently pull on the foam to ensure that it is securely held in place , and some resistance should be felt . as can be seen in fig7 , portions of the foam of the applicator tip , although squeezed , are still substantially wide , as shown at 28 c to retain coolant . in other words , the foam is not so compressed that it cannot retain coolant , in those portions that are compressed between angled portions 24 and 26 . as shown in fig1 , the foam applicator is saturated with a known dental coolant , from a spray can , for example , and the foam will turn to a frosty appearance as it cools . for diagnosing pulpal health , the doctor will apply the chilled foam to tooth structure , and by stimulating the nerve of a tooth , the doctor , through the patient &# 39 ; s response , can ascertain which tooth is the sensitive one causing discomfort or pain . this is important because in some situations the patient may misidentify which tooth is the cause of the pain . in these cases , the tooth believed to cause the pain is called the referring site , but the pain really originates from a symptomatic tooth or teeth causing the problem . use of the diagnostic instrument as described here will quickly and accurately generate a patient response leaving no doubt concerning the identity of the symptomatic tooth . the use of foam , firmly held and saturated with coolant enables controlled diagnosis by the doctor . specifically , as the foam advances against a tooth , more cold will be transferred , and the doctor may advance cautiously if needed , until the patient &# 39 ; s response clarifies where the pain originates . fig1 and 12 show how a doctor may apply the applicator tip to teeth of a patient . for teeth located in the posterior portion of a patient &# 39 ; s mouth , the angled portions 24 and 26 facilitate the doctor being able to see accurately where the applicator tip is positioned . this is shown to a certain extent in fig1 .
an endodontic diagnostic instrument includes a handle configured for receiving a clamp or retainer which engages and clamps an applicator , which may be made of open - celled foam and which is saturated with a coolant or refrigerant . by utilizing the instrument , a doctor may place or selectively position the applicator against a tooth or multiple teeth to determine the tooth which generates pain .