Recession Depth Research Articles

Digital workflow to assess gingival recession coverage independently of the cemento-enamel Junction: a prospective clinical study using the modified coronally advanced tunnel technique with porcine dermal matrix

ObjectivesThe limited number of studies using digital workflows to measure soft tissue changes depend on the cemento-enamel junction (CEJ), which has been reported to be unreliable. Our primary objective was to apply an advanced digital assessment method, measuring independent from the CEJ to evaluate the modified coronally advanced tunnel technique (MCAT) with a porcine dermal matrix (PDM) for gingival recession coverage.Materials and methodsPatients with type RT1 and RT2 gingival recessions were treated with the MCAT and a PDM. Plaster casts (preoperative and 6 months postoperative) were digitalized. Subsequent stereolithography (STL)-files were imported and superimposed in the open-source software GOM Inspect for computer-based analysis. Recession depth, mean root and complete root coverage (mRC and cRC), mean recession reduction (mRR) and gingival thickness were evaluated. Statistical analysis was performed using mixed linear models.ResultsA total of 82 teeth (19 patients) were included in the study. Healing was uneventful in all patients. The mean preoperative recession depth was 1.34 ± 0.92 mm. mRC was 65.06 ± 48.26%, cRC was 25.61%, mRR was 0.87 ± 0.83 mm, and gingival thickness gain was 0.33 ± 0.30 mm, with comparable results for RT1 and RT2. Neither tooth type nor type of jaw had any effect on the amount of root coverage.ConclusionsThe digital evaluation workflow employed offers an approach to evaluate gingival recession coverage outcomes independent of the CEJ. The PDM used in combination with the MCAT shows promising results for root coverage.

Volumetric changes in free gingival graft and gingival unit graft treatments evaluated using an indirect digital method

BackgroundThe aim of this study was to evaluate clinical one-dimensional changes such as root surface coverage, decrease seen in the amount of gingival recession and keratinised gingival width (KGW) obtained throughout a 6-month follow-up period following the treatment of Cairo class II gingival recession with free gingival graft (FGG) and gingival unit graft (GUG). Three-dimensional changes in gingival volume and thickness were also compared digitally using an indirect method. MethodsA total of 20 patients with localised Cairo class II gingival recession were randomly separated into two groups; 10 patients were treated with FGG and 10 patients treated with GUG. Preoperatively and at 6 months postoperatively, the initial position of the gingiva and KGW were recorded for all the patients and plaster models were formed from the obtained impressions with the traditional method. The plaster models were transferred to a digital environment by scanning with a model scanner. Using a software program, changes in gingival papillary height and gingival volume and thickness were compared between the groups and according to the baseline values from The Standard Tessellation Language (STL) files obtained. ResultsCompared to the baseline values, a significant increase was determined in the KGW, and a significant decrease in pocket depth, clinical attachment level, and gingiva recession depth in all the groups (p<0.05). No statistically significant difference was determined between the groups in respect of the changes in mean gingiva thickness, gingiva volume, and mean vertical papillary height (p>0.05). ConclusionThe study results showed that GUG treatment for Cairo class II localised gingival recession is an effective method in respect of increasing gingiva volume and thickness, increasing KGW, coverage of the root surface, and forming tissue contours that allow the patient to easily maintain oral hygiene. However, there was not seen to be any adventage of GUG and FGG over each other.

Diagnostic reproducibility of the 2018 Classification of Gingival Recessions: Comparing photographic and in-person diagnoses.

To assess how the diagnostic reproducibility of the 2018 Classification of Gingival Recession Defects (GRD) could be applied when comparing in-person chairside measurements with photographic measurements. Thirty-four GRD were photographed and evaluated by 4 masked operators. For each case, the operators measured twice recession type (RT), recession depth (RD), keratinized tissue width (KTW), gingival thickness (GT), detectability of the cemento-enamel junction (CEJ), and presence of root steps (RSs), chairside, and on photographs. Intraclass correlation coefficient (ICC) with 95% confidence intervals (CI) was calculated for RD and KTW; Kappa with 95% CI was used for GT, CEJ, and RS; quadratic weighted Kappa with 95% CI was used for RT. RD, KTW, and RT showed excellent overall intra-operator agreement (>0.93), and from good to excellent overall inter-operator agreement (>0.80), for both clinical and photographic measurements. Agreements were lower for GT, CEJ, and RS. Overall clinical and photographic agreements were within 0.1 difference for every variable, except for inter-operator agreement for RS which was 0.72 for clinical measurements and 0.45 for photographic measurements. The lowest overall agreement between clinical versus photographic measurements existed for CEJ (0.28) and RS (0.35). Variables composing the 2018 Classification of GRD are reproducible, both clinically and on photographs, with comparable agreements. The overall agreement was higher for KTW, RD, and RT, and lower for GT, CEJ, and RS, for both clinical and photographic measurements. The comparison between chairside and photographic evaluations indicated fair to excellent agreement for most variables, with CEJ and RS showing fair agreement. As digital diagnostics evolve to facilitate clinical diagnostic measurement, we aimed to assess the effectiveness of intraoral photography for diagnosing gingival recession defects (GRD) according to the 2018 Classification of GRD, compared to traditional clinical examination. Standardized photographs of thirty-four GRD cases were captured. Four masked operators evaluated the same gingival recessions twice in a clinical setting and twice using photographs. Measurement repeatability within and between operators was calculated for both clinical and photographic settings, and the two settings were compared. Continuous measurements such as recession depth and keratinized tissue width, as well as the evaluation of interproximal attachment height (recession type), showed excellent agreement both clinically and photographically. Agreement was lower for gingival thickness and the detectability of tooth anatomical landmarks, such as the cemento-enamel junction and the presence of root steps. Overall, the agreement between chairside and photographic evaluations was generally good, but lower when evaluating tooth anatomical landmarks. The variables composing the 2018 Classification of GRD are reproducible in both clinical and photographic settings, with comparable levels of agreement. However, there was consistently worse agreement for gingival thickness and when evaluating tooth anatomical landmarks.

Factors that influence the results of indirect decompression employing oblique lumbar interbody fusion.

Indirect decompression is one of the potential benefits of anterior reconstruction in patients with spinal stenosis. On the other hand, the reported rate of revision surgery after indirect decompression highlights the necessity of working out prediction models for the radiographic results of indirect decompression with assessing their clinical relevance. To assess factors that influence radiographic and clinical results of the indirect decompression in patients with stenosis of the lumbar spine. This study is a single-center cross-sectional evaluation of 80 consecutive patients (17 males and 63 females) with lumbar spinal stenosis combined with the instability of the lumbar spinal segment. Patients underwent single level or bisegmental spinal instrumentation employing oblique lumbar interbody fusion (OLIF) with percutaneous pedicle screw fixation. Radiographic results of the indirect decompression were assessed using computerized tomography, while MacNab scale was used to assess clinical results. After indirect decompression employing anterior reconstruction using OLIF, the statistically significant increase in the disc space height, vertebral canal square, right and left lateral canal depth were detected (Р < 0.0001). The median (M) relative vertebral canal square increase came to М = 24.5% with 25%-75% quartile border (16.3%; 33.3%) if indirect decompression was achieved by restoration of the segment height. In patients with the reduction of the upper vertebrae slip, the median of the relative increase in vertebral canal square accounted for 49.5% with 25%-75% quartile border (2.35; 99.75). Six out of 80 patients (7.5%) presented with unsatisfactory results because of residual nerve root compression. The critical values for lateral recess depth and vertebral canal square that were associated with indirect decompression failure were 3 mm and 80 mm2 respectively. Indirect decompression employing anterior reconstruction is achieved by the increase in disc height along the posterior boarder and reduction of the slipped vertebrae in patients with degenerative spondylolisthesis. Vertebral canal square below 80 mm2 and lateral recess depth less than 3 mm are associated with indirect decompression failures that require direct microsurgical decompression.

A comparative study of the effects of advanced platelet-rich fibrin and resorbable collagen membrane in the treatment of gingival recession: a split-mouth, randomized clinical trial

AimThis study aimed to assess the effectiveness of advanced platelet-rich fibrin (A-PRF) combined with the pinhole surgical technique (PST) for enhancing root coverage (RC) in individuals with Miller class I or II gingival recessions (GR). Additionally, it compared the clinical effect of A-PRF and resorbable collagen membrane (RCM).Materials and methodsA total of 18 patients, encompassing 36 treatment sides of 18 Miller class I or II, were randomly assigned to the PST + A-PRF side (18 sides) and the PST + RCM side (18 sides). Clinical assessments of various parameters, including plaque index (PI), clinical attachment level (CAL), keratinized tissue width (KTW), recession depth (RD), recession width (RW), and gingival thickness (GT) were conducted at baseline and three months after the surgical procedure. A numeric rating scale (NRS) was also evaluated during the 1st, 2nd, 3rd and 4th days. This study was formally recorded under the TCTR identification number TCTR20230613005 in the Thai Clinical Trials Register-Medical Research Foundation of Thailand (MRF) on 13/06/2023. Furthermore, it was ethically approved by Sana’a University’s Ethical Committee for Medical Research.ResultsWhen comparing the values of 3 months follow-up with the baseline values, intra-side comparison of the PST + A-PRF group showed significant improvements in PI (P = 0.02), CAL (P = 0.01), and RD (P = 0.04), and GT values (P < 0.01). The improvements in the PST + A-PRF group were through the reduction of baseline values of PI, CAL, and RD; the mean reductions in PI, CAL, and RD were 0.44 ± 0.71, 0.33 ± 0.45, and 0.22 ± 0.43 respectively, and a significant increase in GT value (0.44 ± 0.24). While there was an insignificant increase in KTW value with no change in RW values (4.50 ± 0.71, P = 1). In contrast, intra- side comparison of PST + RCM side showed only a significant reduction in PI value (0.44 ± 0.71, P = 0.02) and a significant increase in GT value (0.42 ± 0.26, P = < 0.01). Meanwhile, there were insignificant improvements in CAL (2.89 ± 0.95), KTW (3.97 ± 0.74), and RD (1.94 ± 0.87) values. Regarding inter-side comparison, there were no statistically significant among all variables (p > 0.05). The pain scores of the numeric rating scale were significantly lower on the PST + A-PRF sides compared with the PST + RCM sides, especially on the 1st, 2nd, and 3rd days (P < 0.001).ConclusionBoth A-PRF and RCM showed not wholly satisfactory outcomes in gingival recession treatment. Interestingly, the combination of PST with A-PRF has proven more effective than combining PST with RCM. Additionally, the localized application of A-PRF has been shown to reduce post-operative pain following the pinhole surgical technique.

Clinical Efficacy of Concentrated Growth Factors for the Management of Marginal Tissue Recession: A Systematic Review and Meta-Analysis.

To systematically review existing scientific literature to determine, compare, and evaluate whether concentrated growth factors (CGF) or connective tissue grafts (CTG) is a better treatment alternative for patients with marginal tissue recession (MTR). Electronic databases like PubMed, Embase, Scopus, and Google Scholar were screened from the last 20 years reporting treatment of MTR using CGF or CTG and other techniques. Periodontal parameters like probing depth, clinical attachment level, recession depth, recession width, keratinized tissue width, root coverage, increase in gingival thickness and plaque index, and gingival index were compared. Standardized mean difference was used as a summary statistic measure with a random effect model and P value <0.05 as statistically significant. Six studies fulfilled eligibility criteria and were included in qualitative synthesis, of which only 4 studies were suitable for meta-analysis. The pooled estimate through standardized mean difference signifies that CGF was superior to CTG in the reduction of probing depth, gingival index, and plaque index and gain in clinical attachment level while CTG was superior in reducing the recession depth and recession width. Both the procedures had an overall equal effect on keratinized tissue width and root coverage, but these differences were statistically insignificant ( P >0.05). Publication bias through the funnel plot showed symmetric distribution without systematic heterogeneity. The present study suggests that treatment of MTR with CTG or CGF resulted in clinically favorable outcomes, but no statistically significant differences was observed between these 2 procedures regarding the outcome.

Effectiveness of Tunnelling Modification Technique Using Platelet-rich Fibrin and Connective Tissue Graft in Gingival Recession: A Systematic Review

Background Gingival recession is a concern in aesthetic and functional perspective. The tunneling technique (TT) is one of the effective root coverage treatments in some gingival recession defects and is associated with favorable outcomes. This paper aims to evaluate the effectiveness of platelet-rich fibrin (PRF) and connective tissue graft (CTG) in gingival recession treatment with TT. Methods This systematic review used the PRISMA method and electronic bibliographic searches were conducted on seven databases (Google Scholar, Wiley, Pubmed, Sage, Ovid Technologies, Quintessence Publishing, Springer) from December 2018 to January 2023. The search focused on randomized clinical trials (RCTs) that reported TT outcomes in the treatment of Miller class I and II recession with a minimum of six months follow-up. Results Three out of 399 studies met the inclusion criteria. The three selected studies presented PRF and CTG use in multiple gingival recessions to evaluate tissue condition and clinical parameters before and after the surgical procedure. The clinical parameters evaluated were probing pocket depth (PPD), recession width (RW), width of keratinized gingiva (WKG), and vertical depth of recession (VDR). TT with PRF and TT with CTG is effective in treating gingival recession. PRF is well accepted by patients with a less invasive procedure compared to the CTG procedure. However, TT with CTG showed better results in all parameters at follow-up. Conclusions TT with PRF can be used as an alternative to treat some gingival recession defects. However, TT with CTG produced better clinical results in recession closure.

Growth factor-enhanced matrix combined either with free connective tissue graft or with collagen membrane in the treatment of Miller class II gingival recession

Abstract Purpose The goal of the study was to examine the efficacy of collagen membrane or free connective tissue graft in conjunction with growth factor-enhanced matrix (GEM) for treating Miller class two gingival recession. Patients and methods Twenty sites in 10 patients, with class II Miller gingival recession were allocated randomly to be treated by (GEM21s) with free connective tissue graft (group I) or GEM21s with collagen membrane (group II). Recession width, recession depth, height of keratinized tissue and digital measurements were recorded at baseline, 1, 3, and 6 months. Probing pocket depth, clinical attachment level, gingival thickness, and radiographic parameters were recorded at baseline and 6 months. Root coverage percentage were recorded 6 months postoperative and wound healing index were recorded at 1, 3, and 6 months postoperative. Results Both groups showed significant improvement in all clinical parameters and increase in bone level was observed after 6 months compared to baseline measures. There was no statistically significant difference between both groups except for recession depth at 1 and 3 months after surgery and height of keratinized tissue at 1, 3, and 6 months in favor of group I. Radiographically there was a statistically significant difference (P ≤ 0.05) in amount of labial bone gain and bone density in favor of group I compared to group II. Conclusion GEM21s combined either with free connective tissue graft or collagen membrane led to favorable gingival coverage and radiographical results with better results for free connective tissue graft with GEM21s.

Monetary policy rules and zero lower bound on nominal interest rates in a cost-channel economy

This study analyzed monetary policy rules in a cost-channel economy with a zero lower bound on nominal interest rates (ZLB). The cost channel reflects the supply-side effects of the monetary policy. The ZLB is considered an occasionally binding constraint in a new Keynesian setting. Taylor-type interest rules represent the monetary policy rules, and the novel forward guidance rule introduced in this study is anticipated and endogenous. Under monetary policy rules, a cost-channel economy is more likely to fall into a liquidity trap and remain there longer than a no-cost-channel economy. Accordingly, monetary policy transmission differs from that in a no-cost-channel economy in the ZLB presence. Furthermore, if agents expect future recessions, achieving the inflation target is more challenging in cost-channel economies. Irrespective of the existence of a cost channel, the forward guidance rule reduces the frequency and depth of liquidity-trapped recessions compared to the Taylor-type rules and avoids deflation bias.

Treatment of periodontitis ameliorates the severity and extent of psoriasis-A randomized clinical trial.

To assess the impact of non-surgical periodontitis treatment over conventional dermatological treatment on the severity and extent of psoriasis in patients affected by comorbid psoriasis and periodontitis. Seventy-four patients affected by both psoriasis and Stages I-IV periodontitis were randomized to receive either Steps 1-2 (non-surgical) of periodontal therapy (test group; n = 37) or no treatment (control group; n = 37). The two groups were balanced in terms of psoriasis medications, with the majority of the included patients undergoing biologics (74.0%) as monotherapy, while minor proportions were under systemic medications (13.7%) or none/topical/phototherapy (12.3%). The psoriasis area severity index (PASI) was regarded as the primary outcome. The body surface area (BSA) and the dermatology life quality index (DLQI) were additionally considered as dermatological outcomes. Probing pocket depth, recession depth, clinical attachment level periodontal inflamed surface area, and [full mouth plaque score] etc, periodontal inflamed surface area, and full-mouth plaque and bleeding scores (FMPS/FMBS) were also measured. Periodontal therapy in the test group led to statistically significant lower PASI scores at 10 weeks (mean = 3.15; standard deviation [SD] = 3.78) compared to the control group (mean = 7.11; SD = 6.09) (mean difference [MD] = -4.0; 95% confidence interval [CI]: -6.3, -1.6; p = .001). The test group also showed improvements in BSA (MD = -4.3) and periodontal parameters compared to the control group. DLQI only showed a non-statistically significant tendency (MD = -2.0). Steps 1-2 of periodontal therapy showed an additional effect over conventional dermatological treatment in reducing the severity and extent of psoriasis (Clinicaltrials.gov: NCT05311501).

The Pinhole Surgical Technique - A Distinct Approach for a Marginal Tissue Recession Coverage Using Amniotic Membrane

Introduction: Root coverage procedures are often carried out for compromised aesthetics, dentinal hypersensitivity, difficulty in the maintenance of plaque control, root caries and bone loss. Regenerative attempts are hindered by the root surface’s avascularity and microbiologically compromised condition. Furthermore, freshly created tissue needs to withstand the physical pressures of mastication and procedures related to the maintenance of oral hygiene by the patient. The key issues include surgical challenges, time and patients’ discomfort despite the various surgical methods that have been performed for the root coverage. The complications related to donor site, sparked interest for the development of newer innovative techniques that helps to meet patient’s aesthetic and functional needs. Pinhole surgical technique (PST) being minimally invasive is used in our study to treat gingival recession using amniotic membrane. Materials and Methods: A total of 20 participants were selected randomly with having Miller’s Class I or II recession. Each patient received thorough information on how to practice good oral hygiene. A scaling and root planning process was carried out across the entire mouth. Re-evaluation of research sites was done 1 month after phase I therapy to validate its appropriateness. PST was done randomly on the chosen sites, along with the application of amniotic membrane. Results: All the clinical parameters i.e., recession depth (RD), recession width (RW) and clinical attachment level (CAL), were seen improving significantly at 6 months postoperatively compared to baseline except width of keratinized gingiva (WKG) (P = 0.08) and thickness of keratinized gingiva (TKG) (P = 0.14). All the clinical parameters i.e., RD (P = 0.017), RW (P = 0.017), probing depth (P = 0.03) and CAL (P = 0.05) improved significantly at 12 months postoperatively compared to baseline. However, WKG and TKG showed statistically insignificant changes at 12 months postoperatively (P = 0.08, P = 0.14). Significant difference in Visual Analogue Scale score was seen postoperatively at day 1, 3 and 5. Conclusion: Pinhole surgical approach is used to treat Miller’s Class I–II recession. It may be a better option than the other techniques because it is less invasive, time and money efficient. For the establishment of a normal vasculature and early wound healing, the usage of amniotic membrane as an adjunct is a better alternative.

Accurate Evaluation of Electro-Thermal Performance in Silicon Nanosheet Field-Effect Transistors with Schemes for Controlling Parasitic Bottom Transistors.

The electro-thermal performance of silicon nanosheet field-effect transistors (NSFETs) with various parasitic bottom transistor (trpbt)-controlling schemes is evaluated. Conventional punch-through stopper, trench inner-spacer (TIS), and bottom oxide (BOX) schemes were investigated from single-device to circuit-level evaluations to avoid overestimating heat's impact on performance. For single-device evaluations, the TIS scheme maintains the device temperature 59.6 and 50.4 K lower than the BOX scheme for n/pFETs, respectively, due to the low thermal conductivity of BOX. However, when the over-etched S/D recess depth (TSD) exceeds 2 nm in the TIS scheme, the RC delay becomes larger than that of the BOX scheme due to increased gate capacitance (Cgg) as the TSD increases. A higher TIS height prevents the Cgg increase and exhibits the best electro-thermal performance at single-device operation. Circuit-level evaluations are conducted with ring oscillators using 3D mixed-mode simulation. Although TIS and BOX schemes have similar oscillation frequencies, the TIS scheme has a slightly lower device temperature. This thermal superiority of the TIS scheme becomes more pronounced as the load capacitance (CL) increases. As CL increases from 1 to 10 fF, the temperature difference between TIS and BOX schemes widens from 1.5 to 4.8 K. Therefore, the TIS scheme is most suitable for controlling trpbt and improving electro-thermal performance in sub-3 nm node NSFETs.

Computed Tomography Analysis of the Anterior Epitympanic Recess and Sinus Tympani Depths Among Filipino Adults at the De La Salle University Medical Center

Objective: To assess the depths of the anterior epitympanic recess (AER) and the sinus tympani (ST) among Filipino adults and to classify the AER and ST according to grade and type, respectively. Methods: Design:Retrospective Review of CT Scans Setting: Tertiary Private Teaching Hospital Participants:Scans of 182 non-pathologic ears from patients aged 18 and above with non-pathologic temporal bones (paranasal sinus, screening sinus, temporal bone, facial and cranial) with 0.62mm cuts seen from CT scans from January 01, 2010 to September 31, 2022 were analyzed. The depths of the AER and ST were measured separately and classified according to AER grade and ST type. Results: The mean depth of the AER (AER-D) was 3.64 mm (SD 1.17). No significant difference was seen between right and left ears. The AER grading of the anterior-posterior depth was found to be Grade 1 (&lt;3mm) in 54 ears (29.7%), Grade 2 (3-5mm) in 106 ears (58.2%), and Grade 3 (&gt;5mm) in 22 ears (12.1%). The mean depth of the sinus tympani (ST-D) was 3.30 mm (SD 0.80). Out of the 182 ears, 121 (66.5%) had Type A, 50 (27.5%) had Type B while 11 (6%) had Type C. Conclusion: Majority of the AER depths measured 3-5mm while most of the sinus tympani were Type A. These hidden recesses should be separately analyzed in preoperative planning for cholesteatoma surgery in order to prepare the adequate equipment to be used and approach towards these areas thereby reducing the risk for residual cholesteatomas and recurrence.

Effects of Smokeless Tobacco on Oral Health: A Cross-Sectional Study.

Smokeless tobacco (SLT) consumption poses a significant global public health challenge because of its adverse effects on oral health. Although the detrimental impact of SLT on oral tissues is well-documented, understanding its multifaceted effects is essential for effective prevention and intervention strategies. This study aimed to comprehensively assess the impact of SLT on oral health, focusing on various clinical parameters and their differences between placement and non-placement sites of SLT. A cross-sectional study involving 528 habitual users of SLT was conducted. Clinical parameters included the plaque index (PI), gingival index (GI), gingival bleeding index (GBI), gingival recession (GR), and probing depth (PD). Oral mucosal changes at SLT placement sites have also been reported. Statistical analysis was performed to compare parameters between the placement and non-placement sites. The study involved 528 subjects, mostly male (82%) and aged 21-40 years (mean±SD=31.14±9.10), habitual users of SLT. Prevalent SLT types included tobacco with betel nuts/masala/gutkha (59.9%) and tobacco with lime (54.5%). Significant differences were observed between SLT placement and non-placement sites: higher gingival inflammation (GI) at placement sites (1.54±0.61 vs. 1.45±0.54, p=0.01), lower GBI at placement sites (40.0% vs. 84.3%, p=0.001), and more prevalent GR (65.7% vs. 34.3%, p=0.03) at placement sites. Probing depths ≥ 3 mm were also less frequent at placement sites (2.67±0.72) than non-placement sites (3.37±1.03, p=0.001). These results highlight the detrimental impact of SLT on periodontal health, emphasizing the need for targeted interventions among SLT users. SLT use is associated with adverse effects on oral health, including GI, plaque accumulation, gingival bleeding, GR, and changes in the oral mucosa. Targeted interventions and public health policies are needed to address these issues effectively.

Shear Coaxial Methane–Oxygen Injector Mixing and Combustion Examined by Laser Absorption Tomography

Mixing length scales for methane–oxygen shear-coaxial single-element rocket injectors were experimentally assessed using laser absorption tomography. The laser spectroscopy technique enables quantitative and spatially resolved measurements of carbon monoxide (CO) and temperature within the near-field region, probing rovibrational absorption lines of CO near 5 μm. Multiple injector designs were examined with differing oxidizer post recess depths to compare mixing characteristics. All tests were performed at an oxidizer-to-fuel ratio of 3 with a total propellant flow rate of 0.350 g/s. Planar measurements were taken at 16 axial positions, which collectively captured the first 57 mm of each flame. A tomographic inversion method was applied to obtain radially resolved distributions of temperature and CO mole fraction for each axial position, from which two-dimensional images of the thermochemical structure were generated. Characteristic mixing parameters are defined and extracted from features within the species and temperature profiles to visualize the spatial evolution of CO production. Increasing oxidizer post recess improved mixing due to enhanced shear-induced turbulence and associated radial diffusion of species and temperature; however, the enhancement was nonlinear. This work establishes the first use of laser absorption tomography to directly measure mixing length scales associated with temperature and species profiles in coaxial flames.

Impact of the recessed gate depth on the GaN metal-oxide-semiconductor high electron mobility transistor performances: New insights on mobility extraction

This paper provides a comprehensive study of the impact of the gate recess depth (RD) on the GaN-on-Si MOS-HEMTs DC performances. IDS = f(VGS) and IDS = f(VDS) measurements are conducted at 25 and 150 °C, respectively, in forward and blocking modes. The gate recessed depth (50, 150, and 350 nm) is modulated by adjusting the plasma etching time, which is a critical step for improving the dielectric/GaN interface quality and the gate channel electron mobility. Three distinct regions can be defined separately: the bottom, the sidewall, and the corner region being the junction between the two previous regions. To assess the impact of gate recessed depth (RD) on the several mobilities around the gate cavity first, we applied our previous methodology allowing us to extract the bottom (μbot) and the entire sidewall region mobility (μT), without distinction from the corner. The mobility of the transverse region was found surprisingly to increase with deeper RD. To gain insight into the impact of the RD on this transverse section, a new extraction methodology is proposed to extract separately the gate corner (μcorner) and sidewall (μSW) mobility. These extractions show that the corner mobility is found to be reduced compared to the sidewall one (μcorner &amp;lt; μSW) evidencing the different weighting contributions over the transverse mobility. Moreover, these mobilities are found to be more degraded compared to the bottom one, highlighting the different contributions on the on-state resistance (RON). Indeed, the on-state resistance is lowered with the shallower RD due to the reduced sidewall resistance contribution (lower sidewall length) and despite the incremental contribution of the bottom resistance (larger effective gate length). However, the shallower RD shows an increase in the drain–source leakage current in reason of a lower gate electrostatic control. Technology Computer Aided Design (TCAD) simulations of the three RD morphologies are carried out to validate the experimental trends and the proposed methodology.

Treatment of multiple adjacent gingival recessions using leucocyte- and platelet-rich fibrin with coronally advanced flap: a 12-month split-mouth controlled randomized clinical trial.

This split-mouth randomized study aimed to assess efficacy of leucocyte-platelet-rich fibrin (L-PRF) versus connective tissue graft (CTG) in achieving root coverage (RC) for multiple adjacent gingival recessions (MAGRs) throughout 12-month period. The study enrolled 59 teeth from 12 patients with Miller Class I MAGRs ≥ 2mm on bilateral or contralateral sides. Patients were randomly assigned to receive coronally advanced flap (CAF) with either CTG (control) or L-PRF (test) treatment. Various parameters, including plaque and gingival index, clinical attachment level, recession depth, probing depth, recession width (RW), papilla width (PW), keratinized tissue width (KTW), gingival thickness (GT), percentage of RC, complete root coverage (CRC), and location of the relative gingival margin concerning the cemento-enamel junctions (GMCEJ) after CAF, were recorded at baseline, 3-, 6-, and 12-months post-surgery. On June 29, 2021 the study was registred to ClinicalTrials.gov (NCT04942821). Except KTW and GT gain, all clinical parameters, RC, and CRC were similar between the groups at all follow-up periods (p > 0.05). The higher GT and KTW gains were detected in the control group compared to test group at 12 months (p < 0.05). Both RC and CRC were positively associated with initial PW and GMCEJ, but negatively with initial RW (p < 0.05). The current study concludes that L-PRF were equally effective as CTG in treating MAGRs in terms of RC and CRC. Additionally, RC and CRC outcomes appeared to be influenced by GMCEJ, PW, and RW. L-PRF could represent a feasible substitute for CTG in treating MAGRs.

TCAD Simulation of Novel Recess Gate Common Drain Dual Channel AlGaN/GaN HEMT for Small Signal Performance

In this paper, DC and RF characteristics of Recess Gate Common Drain Dual Channel (CDDC) AlGaN/GaN HEMT have been investigated. The performance of the device in terms of the various figures of merits including gate-source capacitance, drain current, transconductance, and channel conductance has been studied for different recess depths. The threshold voltage is found to decrease by shifting right with increasing recess depth, even though with deeper recess, transconductance increases. It has also been observed that the device operates in enhancement mode with a minimum gate recess depth of 15 nm or more. With increasing recess depth, the drain current starts decreasing due to an increase in channel resistance. Use of recess technology with Al graded barrier layer enhances the performance in terms of gm, ft, and fmax which are 0.003 S, 23, and 46 GHz, respectively, but utilizing gate recess technology alone in CDDC HEMT further enhances device performance and the maximum gm, ft, and fmax are 0.0442 S, 28.43, and 59.21 GHz. The CDDC HEMT retain its advantage for specific applications including PA, LNA, and RF switch with optimized gate recess and graded barrier layer parameters.

Anatomical Possibilities of the Alveolar Bone at the Upper Second Premolar Level.

Background and Objectives: The upper posterior teeth are typically regarded as being exclusively inferior to the maxillary sinus (MS). The expansion of the nasal fossa above the maxillary alveolar base (MAB) needs better investigation. The hypothesis was raised that the MAB in the upper premolar region, which is usually addressed by surgeons for the elevation of the antral floor, is not exclusively beneath the MS. Therefore, we aimed to document the possible upper relations of the MAB as antral, nasal, or both. Materials and Methods: A total of 145 CBCT scans were used to study four types of MAB: type 1-antral; type 2-antral with a palatal recess; type 3-antral and nasal; type 4-nasal. In type 2, the orthoradial width of the alveolar bone, the rectilinear width of the antral floor, and the maximum depth of the palatal recess were measured. For type 3, the MAB width and the straight widths of the antral and nasal segments of the MAB were measured. Results: Type 1 was found in 67.24%, type 2 in 13.45%, type 3 in 16.21%, and type 4 in 3.1% of the 290 MSs investigated. Palatal recesses were found in 11.72% of the MSs on the right side and 15.17% of the MSs on the left side. Types 1 and 2 exhibited strongly statistically significant bilateral symmetry (Pearson's Chi2 = 86.42, p < 0.001). Type 3 correlated equally with contralateral types 1 and 3. The bilateral symmetry for types 1-3 was stronger in the males (Pearson's Chi2 = 47.83, p < 0.001) than in the females (Pearson's Chi2 = 56.96, p < 0.001). There were no statistically significant associations between sex and the unilateral anatomical type. Conclusions: The MAB in the upper second premolar area should not be considered to be exclusively antral during surgeries or in anatomical teaching.

Micro-needling versus acellular dermal matrix in RT1 gingival recession coverage: A randomized clinical trial.

This randomized trial assessed for the first time the efficacy of coronally advanced flap (CAF) followed by micro-needling (MN) in contrast to CAF with acellular dermal matrix (ADM) on gingival thickness (GT, primary outcome), keratinized tissue width (KTW), clinical attachment level (CAL), probing depth (PD), recession depth (RD), recession width (RW), recession reduction (Rec-Red), complete root coverage (CRC) and percentage of root coverage (all secondary outcomes) in management of RT1 gingival recession in patients with thin gingival phenotype. A total of 24 patients (n = 24) with a thin gingival phenotype and single RT1 gingival recession in the aesthetic zone were randomly allocated to test- (CAF + MN; n = 12) or control group (CAF + ADM; n = 12). All clinical parameters were evaluated at baseline, 3 and 6 months. Both groups independently demonstrated significant gain in GT, RW, RD, CAL, PD, Rec-Red, CRC and percentage of root coverage, with reduced PI and BOP (p < .05) at 3 and 6 months, without intergroup differences (p > .05). At 6 months, KTW gain was significantly higher in CAF + MN (5.08 ± 0.9 mm) than in CAF + ADM-group (4.25 ± 1.06 mm; p < .05). Stepwise linear regression model with GT as dependent variable showed that base-line GT was the only statistically significant predictor for GT with a direct correlation between base-line GT and GT after 6 months. CAF followed by MN could represent a promising graft-less approach for increasing gingival thickness, comparable to CAF with ADM, with superior keratinized tissue width improvement, in the treatment of RT1 recession defects in patients with thin gingival phenotype.