Clinical and thermographic evaluation after lower third molar extractions and the application of different photobiomodulation protocols: double-blind randomised clinical trial.

OBJECTIVES: to compare the parameters of pain, oedema, temperature, and soft tissue closure in dental sockets that received two different photobiomodulation (PBM) protocols following extractions. MATERIALS AND METHODS: Thirty-one participants had their teeth 38 and 48 extracted. Subsequently, one of the dental sockets received PBM at a wavelength (WL) of 808 nanometers (808 group- nm) and the other dental socket received the PBM at WLs of 808 nm and 660 nm, simultaneously (808 + 660 group). The PBM was applied immediately after the surgical procedure and on the 3rd and 7th days. RESULTS: The mean of Visual Analogue Scale (VAS) values for pain were 1.45 for the 3rd day and 0.52 for the 7th day in the 808 + 660 and 808 group, respectively. The mean the pogonion-tragus measurement, used to assess facial oedema on the 3rd day, was 15.38 cm (range 13.5-17.5) in the 808 + 660 group and 15.48 cm (range 14.0-17.5) in the 808 group. The mean facial temperatures in the 808 + 660 group were 34.9 degrees Celsius (ºC) (range 33.5-36.4) on the 3rd day and 35 ºC (range 33.4-36.4) on the 7th day. In the 808 group, the mean temperatures were 34.9 ºC (range 33.9-36.2) on the 3rd day and 34.9 ºC (33.7-36.2) on the 7th day. Regarding the dimensions of the dental socket, the mean were similar for both groups. Significant differences between the groups were only observed in the pain parameter and only on the 7th day, being greater for the 808 + 660 group (p = 0.031). CONCLUSIONS: The association of the 660 nm with 808 nm, and the increase in energy did not showed more benefits in pain reduction oedema, or acceleration of the closure of the soft tissues of the dental sockets of lower third molars, in the protocols used here. CLINICAL RELEVANCE: There is no need to combine lasers at wavelengths of 660 and 808 nm to reduce oedema, pain and repair of soft tissues after extraction of lower third molars. CLINICAL TRIAL REGISTRATION: This trial was registered in the Brazilian Registry of Clinical Trials (ReBEC) with the following code: RBR-66pyrh8, on 29th December, 2022.

Shortening of primary dentin etching time and its implication on bond strength.

OBJECTIVE: The aim of this study was to investigate the influence of shortening the etching time on the bond strength of a conventional and a self-etching primer adhesive system used in primary tooth dentin. METHODS: Flat dentin surfaces were obtained from 24 primary molars, randomly assigned to 4 experimental groups. The adhesive systems Single Bond and Clearfil SE Bond were applied in two groups according to the manufacturers' recommendations. In the other two groups, the adhesives were applied after half-time of acid etching, 7 s for Single Bond and 10 s for Clearfil SE Primer. Resin crowns were built up and after 24 h storage in water at 37 degrees C, the teeth were sectioned to produce beams with cross-sectional area of approximately 0.49 mm2. Specimens were tested in tension at 0.5 mm/min until failure. Fractured specimens were analyzed to determine the failure mode. RESULTS: Tensile bond strengths for Single Bond in primary dentin were higher than for Clearfil SE Bond. Shortening of acid etching time improved bond strength only for Single Bond, while no statistically significant difference was observed for Clearfil SE Bond when both etching times were compared. SIGNIFICANCE: No detrimental effect on bond strength was observed when the time of acid etching was shortened in 50%. Shortening the time for a procedure in a small child without compromising the quality of the work is a very important finding for the practicing pediatric dentist.

Effect of 2% chlorhexidine on microtensile bond strength of composite to dentin.

PURPOSE: To evaluate the effect of 2% chlorhexidine on the microtensile bond strength of composite resin to dentin treated with three dentin bonding systems. MATERIALS AND METHODS: Flat dentinal surfaces were prepared in 24 extracted human third molars. Teeth were randomly divided into 8 distinct experimental groups according to the adhesive applied (Prime & Bond NT, Single Bond and Clearfil SE Bond), the application (yes/no) of chlorhexidine, and the time point at which it was applied (before or after acid etching the dentin). Composite resin blocks were built up over treated surfaces, and teeth were then stored in water at 37 degrees C for 24 h. Samples were thermocycled, stored under the same conditions, and then vertically sectioned, thus obtaining specimens with 1.0 +/- 0.1 mm2 cross-sectional area. Specimens were stressed in tension at 0.5 mm/min crosshead speed. Bond strength results were evaluated using a one-way ANOVA (p < 0.05). The modes of failures were verified using optical microscopy. Dentin disks were obtained from 3 additional teeth treated in the same manner for observation under SEM. The most representative samples of fractured specimens were also observed under SEM. RESULTS: No statistically significant differences of bond strength values were found between any groups. Failures occurred mainly within the bond; exclusively adhesive fractures (adhesive-dentin) were not observed. CONCLUSION: The 2% chlorhexidine solution, applied before or after acid etching of the dentin, did not interfere with the microtensile bond strength of composite resin to the dentin treated with Prime & Bond NT, Single Bond, or Clearfil SE Bond bonding systems.