The tissue renin-angiotensin system (tRAS) and the impact of its inhibition on inflammation and bone loss in the periodontal tissue.

Recently, the existence of the tissue renin-angiotensin system (tRAS) has been described for multiple tissues in humans, suggesting its fundamental role in the progression of inflammation and fibrosis. Evidence arises that tRAS might have an impact on the progression of periodontitis and bone loss. However, neither the role of tRAS nor its impact as a therapeutic target have been systematically evaluated for periodontal tissue. The present study sought to characterise tRAS in the periodontal tissue and the effect of its inhibition on periodontal inflammation and bone loss. This systematic review was performed according to the preferred reporting items for systematic reviews and meta analyses (PRISMA) statement. Literature was searched using Web of Science core collection (Web of Science), Medline (Ovid), Cochrane central register of controlled trials (Ovid), Cochrane database of systematic reviews (Ovid), Google Scholar databases and the references of the retrieved studies in March 2020. Information on study design, sample size, population, procedure, type of intervention, observation time, as well as information on sources of bias, was extracted and evaluated. From 455 identified articles, 17 were included in the qualitative synthesis and 11 were included in the quantitative synthesis. Outcomes of studies indicated that the inhibition of tRAS components led to a reduction of periodontal bone loss and inflammation, dependent on the inhibitor used. The findings suggested an important role of tRAS in the periodontal tissue and indicate a potential therapeutic approach for periodontal diseases.

Clinical and Patient-reported Outcomes of a Zirconia Oral Implant: Three-year Results of a Prospective Cohort Investigation.

The objective of this study was to determine the clinical, radiographic, and patient-reported outcomes of a 1-piece alumina-toughened zirconia implant restored with single crowns (SCs) or 3-unit fixed dental prostheses (FDPs) after 3 y of observation. Forty patients received 53 implants, placed in a 1-stage operation with immediate temporization. Finally, 50 implants were restored with 24 SCs and 13 FDPs. To evaluate peri-implant bone loss, standardized radiographs were taken at implant insertion, at final restoration delivery, and after 1 and 3 y. Additionally, several soft tissue parameters and patient-reported outcome measures were evaluated. Linear mixed models with random intercept for each patient and patients as clusters were used to compare subgroups. Three patients did not receive a SC due to early implant loss, and 1 patient died. As a result, 36 patients with 49 implants were followed-up for 3 y, giving a cumulative survival rate of 94.2%. The average marginal bone loss amounted to 0.79 mm (SCs, 0.47 mm; FDPs, 1.07 mm; P < 0.001). After the delivery of the final prosthetic restoration, further bone loss was not statistically significant (0.09 mm; P = 0.700). Probing depth, clinical attachment level, and modified bleeding index increased significantly at the implant sites, whereas gingival recession decreased significantly. Compared with the pretreatment questionnaires, the patient-reported outcome measures showed a permanently improved perception of function, aesthetics, sense, speech and self-esteem. The survival rate of the investigated ceramic implant system seems to be comparable to reported survival rates of titanium implants when immediately restored. The recorded parameters suggest its potential for clinical utilization.

The use of cone beam computed tomography to predetermine root canal lengths in molar teeth: a comparison between two-dimensional and three-dimensional measurements.

OBJECTIVES: The aim of this study was to evaluate the accuracy of two-dimensional (2D) and three-dimensional (3D) root canal length measurements in molar teeth using cone beam computed tomography (CBCT). MATERIALS AND METHODS: Root canal lengths of twenty molar teeth were measured with two different CBCT approaches. After adjusting the CBCT images, 2D measurements were performed within the sagittal plane between the apical foramen and the coronal reference (cusp). The 3D approach measured centrically in axial planes. A linear mixed model with random intercepts was fitted to compare differences between methods (2D and 3D). The correlation between CBCT measurements and the actual root canal length was evaluated using the Pearson correlation coefficient. RESULTS: Differences between 3D measurements and the actual root canal lengths were significantly smaller compared to the 2D approach (p < 0.001). Mean differences were 0.32 and 0.58 mm, respectively. A high correlation was found between the actual root canal length and 3D measurements (Pearson correlation coefficient = 0.97). Compared to the actual root canal length, 80 % of the 3D measurements were within the limits of ±0.5 mm. CONCLUSIONS: 3D measurements of root canals in molar teeth are more accurate than simple 2D measurements and show a high correlation to the actual lengths. CLINICAL RELEVANCE: In cases where a CBCT is already available, root canal lengths in molar teeth can be accurately predetermined using a standardized 3D approach.

Effective dose span of ten different cone beam CT devices.

OBJECTIVES: Evaluation and reduction of dose are important issues. Since cone beam CT (CBCT) has been established now not just in dentistry, the number of acquired examinations continues to rise. Unfortunately, it is very difficult to compare the doses of available devices on the market owing to different exposition parameters, volumes and geometries. The aim of this study was to evaluate the spans of effective doses (EDs) of ten different CBCT devices. METHODS: 48 thermoluminescent dosemeters were placed in 24 sites in a RANDO(®) head phantom. Protocols with lowest exposition parameters and protocols with highest exposition parameters were performed for each of the ten devices. The ED was calculated from the measured energy doses according to the International Commission on Radiological Protection 2007 recommendations for each protocol and device, and the statistical values were evaluated afterwards. RESULTS: The calculation of the ED resulted in values between 17.2 µSv and 396 µSv for the ten devices. The mean values for protocols with lowest and highest exposition parameters were 31.6 µSv and 209 µSv, respectively. CONCLUSIONS: It was not the aim of this study to evaluate the image quality depending on different exposition parameters but to define the spans of EDs in which different CBCT devices work. There is a wide span of ED for different CBCT devices depending on the selected exposition parameters, required spatial resolution and many other factors.

Surface roughness measurement by means of polychromatic speckle elongation.

A new approach for determining the roughness of engineering surfaces that is applicable to industrial in-process measurements is introduced. Laser speckle patterns, arising from light scattered from rough surfaces that are illuminated by polychromatic laser light, are detected in the far-field region. The incoherent superposition of these light intensities and the angular dispersion cause the effect of speckle elongation. This is characterized by increasing speckle widths and leads to a radial structure of the speckle patterns. With increasing surface roughness, the elongation is replaced more and more by the decorrelation of the monochromatic speckle patterns for the different wavelengths. Such effects were detected with the CCD technique and analyzed by local autocorrelation functions of intensity fluctuations that were calculated for different areas of the speckle patterns. The results of surface-roughness determination by means of the speckle elongation effect are presented.