This study measured the radiant power (mW), irradiance (mW/cm 2 ) and emission spectra (mW/cm 2 /nm) of 22 new, or almost new, light curing units (LCUs): -Alt Lux II, BioLux Standard, Bluephase G2, Curing Light XL 3000, Demetron LC, DX Turbo LED 1200, EC450, EC500, Emitter C, Emitter D, KON-LUX, LED 3M ESPE, Led Lux II, Optilight Color, Optilight Max, Optilux 501, Poly Wireless, Radii cal, Radii plus, TL-01, VALO Cordless. These LCUs were either monowave or multiple peak light emitting diode (LED) units or quartz-tungstenhalogen LCUs used in anterior and posterior teeth. The radiant power emitted by the LCUs was measured by a laboratory grade laser power meter. The tip area (cm²) of the LCUs was measured and used to calculate the irradiance from the measured radiant power source. The MARC-Patient Simulator (MARC-PS) with a laboratory grade spectrometer (USB4000, Ocean Optics) was used to measure the irradiance and emission spectrum from each LCU three times at the sensor located on the facial of the maxillary central incisors and then separately at the occlusal of a maxillary second molar. The minimum acceptable irradiance level was set as 500 mW/cm 2 . Irradiance data was analyzed using two-way ANOVA and the radiant power data was analyzed by one-way ANOVA followed by Tukey test (α=0.05). In general, the irradiance was reduced at the molar tooth for most LCUs. Only the Valo, Bluephase G2 and Radii Plus delivered an irradiance similar to the anterior and posterior sensors greater than 500 mW/cm 2 . KON-LUX, Altlux II, Biolux Standard, TL-01, Optilux 501, DX Turbo LED 1200 LCUs delivered lower irradiance values than the recommended one used in molar region, KON-LUX and Altlux II LCUs used at the maxillary incisors. Bluephase G2 and Optilight Max delivered the highest radiant power and KON-LUX, Altlux II and Biolux Standard delivered the lowest power. The emission spectrum from the various monowave LED LCUs varied greatly. The multi-peak LCUs delivered similar emission spectra to both sensors.

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The aim of this retrospective study was to evaluate the survival and associated factors for the longevity of direct posterior restorations and to verify whether the geographic location of public health units could influence the long-term survival of such restorations. Data were extracted from electronic patient files of the Brazilian public oral health services. The sample comprised 2,405 class I and II restorations performed 4 to 24 years ago (mean, 8.9 years) in 351 patients (6.8 teeth/patient) across 12 public health units located in different city regions (42 professionals—55 restorations). The restoration was considered successful if it had not been repaired or replaced at the time of evaluation; failure was defined as replacement of the restoration, the need for endodontic treatment, tooth/restoration fracture or tooth extraction. Data were analyzed using the Kaplan-Meier test for restoration survival and Cox regression to evaluate the factors associated with failure. The majority of the restorations involved the use of amalgam (85%), involved a single face (70%), and were without pulp/dentin capping (85%). The overall survival rate was 95%, and the mean observation time was 8.9 years. The restoration survival was 79% (95% CI: 60.6–89.5) over 24 years, and the mean survival time was 22.2 years (95% CI: 21.9–22.6 years). The annual failure rate up to 24 years was 0.9%. After the adjustment, only the number of restored faces and the geographic location where the restoration was performed remained associated with failure of the restoration. The direct posterior restorations performed at the evaluated public health service units presented high survival rates. The restorations of people with lower access to POHS had lower survival rates. Class I restorations presented higher survival rates than class II restorations with two or more faces, regardless of the restorative material used.

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The use of one fiberglass post for restoring molars with direct composite resin resulted in higher fracture resistance than did the use of two fiberglass posts; it also resulted in better tooth remaining strain and stress distribution and more reparable fracture modes than were seen in the group without a fiberglass post.