EFFECTS of ORTHODONTIC COOLANT SPRAYS on PULP TEMPERATURE

OBJECTIVES:

Thermal superelastic wires are more and more used for initial alignment of teeth , with both labial and lingual appliances . To engage easily the wire into the arch slots , clinicians have to cool it with dichlorodifluorométhane . This in vitro study was carried out to evaluate the intrapulpal temperature change induced by coolant sprays when dabbed on wire , in order to assess the potential risk of pulp damage.

METHODS:

6 human bicuspids recently extracted for orthodontic reasons were bonded with metallic brackets on their buccal side and set in a Typodont model ; a 017x025 Copper Niti wire were tied . A K- thermocouple was placed in the pulpar chamber of each tooth so as to register temperature for 90 sec after cooling through an AGILENT 3497 A machine. Two differents applicators were tested : 2 sec with direct spray close to the middle of the wire ; 5 sec with a cotton pellet . 95 experiments were achieved for each method.

RESULTS:

For each parameter , symmetrical sensors were compared (Mann Whitney test) .

SPRAY

Temperature change is maximum beside the cooling spot :

-14,57 ° +- 3,7 ; - 17,23 +- 5,52 p< 0,001

Time during temperature is 10° below the initial temperature concerns only this teeth :

71,31 sec +- 18,16 ; 62,43 +- 24 ,45 p=0,2840

PELLET

Temperature change is maximum beside the cooling spot :

-7,17 ° +- 3,32 ; - 5,96 +- 3,02 p< 0,001

Time during temperature is 10° below the initial temperature concerns only this teeth :

34,30 sec +- 29,41 ; 44,31 +- 24, 88 p=0,3613

CONCLUSION:

Coolant sprays can be used in orthodontics without resulting in pulpal injury.