The goal of the study was to determine the effects of software updates on the trueness and precision of digital impressions obtained with a variety of intraoral scanner (IOS) systems.
 
  Seven IOS systems were investigated. Each system was tested using two versions of software, with the second version being the latest at the time of conducting the study. Scans were performed on a custom mandibular typodont model with natural teeth that were either unrestored or restored with amalgam, composite, lithium disilicate, zirconia, and gold. Eight scans were obtained for each software version on any of the tested IOS systems. Experimental IOS scans were compared against an industry-standard master scan of the typodont obtained with an ATOS Capsule scanner proven to have a trueness of 3 µm and a precision of 2 µm. Isolation of each substrate material on the digital experimental and master scans was achieved using the Geomagic metrology software for subsequent analysis of the substrate influence on accuracy. A genera although it appears that these variations are within the clinical acceptability levels.
 Software updates have a statistically significant effect on the trueness and precision of different IOS systems. These updates can have both positive and negative effects on scan accuracy, although it appears that these variations are within the clinical acceptability levels.
  Some modifications of orthodontic appliances such as the rapid maxillary expansion (RME) device with a Hyrax screw or Herbst are fabricated using traditional investment casting (lost-wax casting).  https://www.selleckchem.com/products/Temsirolimus.html  This is precise but very labor-intensive. New technologies enable us today to use direct selective laser sintering (SLS) to produce freeform metallic structures. These machines are very expensive and only available in specialized laboratories. The aim of this investigation was to combine fused filament fabrication (FFF) 3D printing with wax-based filaments to produce orthodontic appliances via investment casting.
 
  For demonstration purposes, a lingual arch, a palatal arch, and an RME appliance were digitally designed based on an intraoral scan. The *.stl files were sliced and printed with a dual-nozzle FFF printer. The object was printed with a wax-based filament especially suited for investment casting, and support structures were printed with water-soluble polyvinyl-alcohol (PVA) filament. The printed objects were cast in metal and finished.
 
  All appliances were successfully cast and polished. They were provisionally placed intraorally. The fit was clinically very good and comparable to traditionally crafted appliances. The printing and handling of the parts made of these special filaments is challenging.
 
  With this experiment, the successful production of investment casting using FFF printing was shown for the first time.
 With this experiment, the successful production of investment casting using FFF printing was shown for the first time.
  To describe the step-by-step procedure of a novel surgical technique consisting of a combination of the laterally closed tunnel (LCT) and the modified coronally advanced tunnel (MCAT) (ie, LCT/MCAT), designed to treat multiple mandibular adjacent gingival recessions (MAGR) and to present the clinical outcomes obtained in 11 consecutively treated patients.
 
  Eleven systemically and periodontally healthy patients (7 females, mean ± SD 33.62 ± 14.6 years, min. 19 years max. 67 years) with a total of 40 adjacent mandibular RT1 (ie, Miller Class 1 and 2) gingival recessions with a minimum depth ≥ 3 mm, were consecutively treated with LCT/MCAT, in conjunction with an enamel matrix derivative (EMD) and subepithelial palatal connective tissue graft (SCTG). Treatment outcomes were assessed at baseline and at 12 months postoperatively. Prior to surgery and at 12 months postoperatively, recession depth (RD) and recession width (RW) were evaluated. The primary outcome variable was complete root coverage (CRC, ie 100% root coverage), the secondary outcome was mean root coverage (MRC).
 
  Postoperative pain and discomfort were low and the healing was uneventful in all cases without any complications. At 12 months, statistically significant (P < .05) root coverage (RC) was obtained in all patients. CRC was obtained in five patients with a total of 21 recessions, while MRC measured 92.9% (ie, 3.75 mm). In seven patients (ie, 63.6%), RC amounted to > 93% while the minimum RC per patient measured 83.76%.
 
  The results of the present case series suggest that the LCT/MCAT is a valuable technique for the treatment of mandibular RT1 MAGR.
 The results of the present case series suggest that the LCT/MCAT is a valuable technique for the treatment of mandibular RT1 MAGR.
  Bleaching sensitivity (BS) is the most common adverse effect of tooth bleaching treatments. This study evaluated the effect of adding 1% sodium hexametaphosphate (SHMP) on BS and the whitening effectiveness of a bleaching gel.
 
  Two maxillary quadrants from 26 patients were randomly assigned to the experimental and control groups in a split-mouth design. In the control group the at-home bleaching gel containing 3% hydrogen peroxide, and in the experimental quadrant the same gel with 1% SHMP, were applied in individual trays for 6 hours per night for 2 weeks. The patients' sensitivity to cold and touch as well as spontaneous sensitivity were recorded based on a visual analog scale (VAS). Changes in shade guide units (ΔSGU) and ΔE were measured using a spectrophotometer. Data were analyzed using the Kolmogorov-Smirnov, Mann-Whitney U, Wilcoxon signed-rank test, and independent sample t test.
 
  Twenty-four patients completed the study. After 2 weeks, the sensitivity to cold and touch was significantly lower in the intervention group compared to the control (P = .015 and P = .039, respectively). The spontaneous sensitivity revealed no significant alteration between these two groups and during the bleaching period in each group (P > .050). Regarding both color measurements, the bleaching effectiveness in both groups was comparable, with no noticeable difference (P > .050).
 
  The application of 1% SHMP was able to reduce the BS with no detrimental effect on the at-home bleaching effectiveness. (Quintessence Int 2021;52596-605; doi 10.3290/j.qi.b1098303).
 The application of 1% SHMP was able to reduce the BS with no detrimental effect on the at-home bleaching effectiveness. (Quintessence Int 2021;52596-605; doi 10.3290/j.qi.b1098303).