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Volumetric measurement of dentoalveolar defects by means of intraoral 3D scanner and gravimetric model
摘要： The aim of this study was to evaluate the accuracy in volumetric measurements obtained on an experimental model using an intraoral scanner and a gravimetric method. Three identical partial dentate maxillary acrylic models with three fabricated alveolar defects, in anterior and posterior regions, were scanned using an intraoral scanner (20 scans/defects). The defects differed in terms of size and distance of neighbouring teeth. As references, replicas of each defect were created using a dimensional stable silicone impression material. After measuring the mass of each replica, the volume was calculated by dividing the mass of each replica by the density of the impression material. The defects had a volume, according to the gravimetric method, ranging from 40.5 to 143.7 mm3. The scans were imported to metrology software for analyses. Accuracy was determined in terms of trueness and precision. The mean trueness for all defect types was 0.168 mm3 (SD 0.691, range 2.82). There was no statistical significant difference between the mean trueness for all defects measured (p = 0.910). The mean precision for all defect types was 0.147 mm3 (SD 0.524, range 2.86). There were no statistical significant differences between the dental models in regard to mean precision (p = 0.401), however, there were statistical significant differences between defects in position 1 and 2 (p = 0.002) and 1 and 3 (p = 0.001). Based on the findings of this study, the intraoral scanner utilized in the current study presented an acceptable level of accuracy when measuring volume of defects.
关键词： Volumetric measurement,Intraoral scanning,Surgical techniques,Wound healing,Tissue alterations
更新于2025-09-23 15:22:29
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Laser Treatment of Accidental Tattoos: Experience at a Tertiary Referral Center
摘要： Background: To date, information on laser treatment of accidental tattoos is limited. Objectives: This study analyzes the efficacy and safety of quality-switched ruby, quality-switched Nd:YAG and picosecond lasers in the treatment of accidental hyperpigmentation in a larger patient cohort. To date, there is limited information on laser therapy of accidental hyperpigmentation. Methods: We conducted a retrospective systematic single-center analysis on 70 patients, which presented with accidental hyperpigmentation at the Dermatology Department of the University Hospital of Zurich between 2008 and 2017. Patients with accidental tattoos due to road injuries, explosives or other traumas and iatrogenic measures were included. We analyzed the data including laser parameters such as wavelength, energy density, spot size and intervals between the sessions. Also, the number of sessions performed and the overall success were registered. Results: We treated 38 patients by quality-switched nano- and/or picosecond laser therapy and completed the treatment in 28 cases within a mean number of 3–5 laser sessions. No complications occurred. Conclusion: We demonstrate the validity and safety of quality-switched and picosecond lasers in the treatment of accidental hyperpigmentation. Using a combination of different wavelengths and pulse lengths on the same lesion and gradually increasing the fluence in the course of the laser treatment is recommendable to increase efficacy. We observed a tendency towards faster elimination of facial accidental tattoos and/or originating from road injuries compared to tattoos located on the extremities and those caused by explosions, piercings or iatrogenic measures or consisting of metal pigment particles.
关键词： Laser treatment,Tattoo pigment,Surgical techniques,Dermatologic surgery
更新于2025-09-23 15:21:01