In Vivo Pulp Temperature Changes During Class V Cavity Preparation and Resin Composite Restoration in Premolars.

OBJECTIVE: This in vivo study evaluated the influence of the sequence of all restorative steps during Class V preparation and restoration in human premolars on pulp temperature (PT). METHODS AND MATERIALS: Intact premolars with orthodontic extraction indication of 13 volunteers received infiltrative anesthesia and isolation with rubber dam. An occlusal preparation was made with a high-speed diamond bur under air-water spray until the pulp was minimally exposed, then a thermocouple probe was inserted within the pulp. A deep, 2.0-mm depth Class V preparation was made using a high-speed diamond bur under air-water spray. Three restorative techniques were performed (n=7): Filtek Z250 placed in two increments (10-second exposure, shade:A2, 3M ESPE, St. Paul, MN, USA), Filtek Z350 XT (40-second exposure, shade:A3D, 3M ESPE) and Tetric N Ceram Bulk Fill (10-second exposure, shade:IVA, Ivoclar Vivadent, Schaan, Liechtenstein), both placed in a single layer. Bonding layer and resin composite were exposed to light from the same Polywave LCU (Bluephase 20i, Ivoclar Vivadent). The peak PT and the difference between peak PT and baseline (ΔT) values were subjected to two-way, repeated measures analysis of variance (ANOVA), followed by the Bonferroni post-hoc test (α=0.05). RESULTS: Cavity preparation and etch & rinse procedures decreased the PT values (p<0.001). The 40-second exposure of Filtek Z350 caused the highest peak PT values (38.7±0.8°C) and the highest ΔT values (3.4±0.8°C), while Tetric N Ceram Bulk Fill showed the lowest values (-1.6±1.3°C; p=0.009). CONCLUSION: None of the evaluated procedures resulted in a PT rise near to values that could offer any risk of thermal damage to the pulp.

Controlling In Vivo, Human Pulp Temperature Rise Caused by LED Curing Light Exposure.

OBJECTIVE: The objective of this study was to evaluate the in vivo effectiveness of air spray to reduce pulp temperature rise during exposure of intact premolars to light emitted by a high-power LED light-curing unit (LCU). METHODS AND MATERIALS: After local Ethics Committee approval (#255945), intact, upper first premolars requiring extraction for orthodontic reasons from five volunteers received infiltrative and intraligamental anesthesia. The teeth (n=9) were isolated using rubber dam, and a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted directly into the coronal pulp chamber. Real-time pulp temperature (PT) (°C) was continuously monitored, while the buccal surface was exposed to a polywave LED LCU (Bluephase 20i, Ivoclar Vivadent) for 30 seconds with simultaneous application of a lingually directed air spray (30s-H/AIR) or without (30s-H), with a seven-minute span between each exposure. Peak PT values were subjected to one-way, repeated-measures analysis of variance, and PT change from baseline (ΔT) during exposure was subjected to paired Student's t-test (α=0.05). RESULTS: Peak PT values of the 30s-H group were significantly higher than those of 30s-H/AIR group and those from baseline temperature (p<0.001), whereas peak PT values in the 30s-H/AIR group were significantly lower than the baseline temperature (p=0.003). The 30s-H/AIR group showed significantly lower ΔT values than did the 30s-H group (p<0.001). CONCLUSION: Applying air flow simultaneously with LED exposure prevents in vivo pulp temperature rise.

Randomized Double-blind Clinical Trial of Bleaching Products in Patients Wearing Orthodontic Devices.

OBJECTIVES: This double-blind randomized clinical trial evaluated tooth sensitivity (TS) and the effectiveness (EF) of two types of bleaching agents (Trèswhite Ortho [TWO] and Trèswhite Supreme [TWS]) when used in patients wearing orthodontic appliances. METHODS AND MATERIALS: Forty patients between the ages of 18 and 40 years were randomly stratified, with an equal allocation rate, into two groups (n=20), according to the bleaching agent applied. Tooth color of the six maxillary anterior teeth was measured before and after the treatment with a spectrophotometer. The TS was recorded on three scales before and during the bleaching treatment. RESULTS: With regard to EF, a significant reduction was found (ranging from 7.3-9.6 and 5.3-9.5 Vita scale units for TWO and TWS, respectively, p<0.001); however, there was no statistical difference between the groups (p>0.63). The number of patients with sensitivity was 58.8% and 73.3% for TWO and TWS groups, respectively (p=0.53); however, with each of the three scales used, the intensity of sensitivity was low and there was no statistical difference between TWO and TWS (p>0.05). CONCLUSIONS: In spite of producing a side effect of low TS, the two bleaching treatments tested were effective for dental bleaching in patients with fixed orthodontic appliances.