E. Mizrahi et al., TOOTH SURFACE AND PULP CHAMBER TEMPERATURES DEVELOPED DURING ELECTROTHERMAL BONDING, American journal of orthodontics and dentofacial orthopedics, 109(5), 1996, pp. 506-514
The rationale of electrothermal bonding is based on the premise that w
hen an electric current is passed across the beaks of tweezers holding
a stainless steel orthodontic bracket, heat will be generated by virt
ue of the electrical resistance of the steel bracket. This study was c
arried out to evaluate the temperatures generated on the tooth surface
at the bracket/tooth interface and within the pulp chamber during ele
ctrothermal bonding. Temperatures were recorded with 5 and 7.5 A curre
nt levels applied as al second pulse with time intervals between pulse
s of 1, 2, 3, and 4 seconds. The data showed that after three pulses w
ith a 5 A current, the temperature on the tooth surface ranged between
43.3 degrees C (4 second intervals) to 53.6 degrees C (1 second inter
vals). By using a 7.5 A current, the temperature ranged from 77.5 degr
ees C (4 second intervals) to 85.9 degrees C (1 second intervals). The
pulp chamber temperatures were evaluated in vitro for a mandibular in
cisor, the maxillary central and lateral incisors, a canine, a premola
r, and a molar. The pulp chamber temperature of a mandibular incisor r
esponded most, whereas that of premolars and molars responded least to
temperature changes on the labial surface. The increase in mandibular
incisor pulp chamber temperature after three pulses was 2.1 degrees C
for 5 A and 2.8 degrees C for 7.5 A current while for a premolar the
increase ranged from 0.9 degrees C to 1.6 degrees C. On the basis of c
urrent evidence the increase in pulp chamber temperatures during elect
rothermal bonding may be considered to be clinically safe.