Assessment of eruption source parameters using infrasound and plume modelling: a case study from the 2021 eruption of Mt. Etna, Italy.

Atmospheric injection of volcanic ash during eruptions is a threat to aviation. Reliable forecast of airborne ash dispersal relies on empirical and numerical models. Key inputs into these models are so-called eruption source parameters such as the rate at which pyroclastic material is ejected from the vent and the maximum height of eruptive columns. Here, we use infrasound data recorded during eruptive activity in June 2021 at Mt. Etna, Italy, to demonstrate its potential for assessment of eruption rates in near-real time. We calculate a time series of flow velocity at the vent using data corrected for topographic scattering, and the effect of vent geometry on the acoustic source radiation. We obtain values of flow velocity of 50-125 m/s during a period of sustained, paroxysmal, activity. We use independent estimates from other ground-based remote sensing data to validate our results. Further, we use the infrasound-derived flow velocities as input into a 1D plume model to estimate the maximum height of the eruption column. Our results suggest that infrasound technology holds promise to assess eruption rates and inform modelling of volcanic plumes. We anticipate that implementation of real-time operational workflows based on infrasound data and plume modelling will impact decision-making and risk mitigation at active volcanoes.

Implant Placement with Simultaneous Guided Bone Regeneration Using Advanced Platelet-Rich Fibrin and a Deproteinized Bovine Bone Mineral: A 2-Year Retrospective and Comparative Study.

A lack of bone volume may compromise a correct three-dimensional implant placement. This study was designed to evaluate the clinical and radiographic outcomes of simultaneous horizontal guided bone regeneration (GBR) performed using autogenous bone or blood-derived products mixed with a bone xenograft. The study population consisted of patients operated on using one of two clinical protocols for GBR: group A, which used autogenous bone mixed with a bone xenograft, and group B, which used advanced platelet-rich fibrin (A-PRF) mixed with a bone xenograft. The primary outcome was the clinical gain in the peri-implant defect. The secondary outcomes included an analysis of the postoperative healing, periodontal parameters, marginal bone loss, and occurrence of adverse events. All of the surgeries were carried out successfully. One patient in each group experienced a case of early implant loss, and three patients (one in group A and two in group B) presented biologic complications. The mean peri-implant vertical defect heights at baseline in group A and group B were 3.6 ± 0.9 mm and 4 ± 1.5 mm, respectively (P = .382). No statistically significant differences in the mean residual defect heights (P = .521) or in the postoperative wound healing (P = .611) were observed. Stable peri-implant marginal bone levels were recorded after loading in both groups. The use of A-PRF combined with a particulate bone xenograft and covered with a fixed collagen membrane may provide clinical results similar to those obtained via autogenous bone mixed with bone xenograft.

Atmospheric waves and global seismoacoustic observations of the January 2022 Hunga eruption, Tonga.

The 15 January 2022 climactic eruption of Hunga volcano, Tonga, produced an explosion in the atmosphere of a size that has not been documented in the modern geophysical record. The event generated a broad range of atmospheric waves observed globally by various ground-based and spaceborne instrumentation networks. Most prominent was the surface-guided Lamb wave (≲0.01 hertz), which we observed propagating for four (plus three antipodal) passages around Earth over 6 days. As measured by the Lamb wave amplitudes, the climactic Hunga explosion was comparable in size to that of the 1883 Krakatau eruption. The Hunga eruption produced remarkable globally detected infrasound (0.01 to 20 hertz), long-range (~10,000 kilometers) audible sound, and ionospheric perturbations. Seismometers worldwide recorded pure seismic and air-to-ground coupled waves. Air-to-sea coupling likely contributed to fast-arriving tsunamis. Here, we highlight exceptional observations of the atmospheric waves.

The Effect of an Optimized Diet as an Adjunct to Non-Surgical Periodontal Therapy in Subjects with Periodontitis: A Prospective Study.

Diet and nutrition are generally categorized as modifiable lifestyle risk factors for the development of periodontal disease because diet may influence a person's inflammatory status. This study aimed to evaluate the efficacy of the application of a diet plan focused on reducing inflammation and oxidative stress in treating periodontitis. Subjects suffering from periodontitis were divided into two groups. Both groups underwent non-surgical periodontal therapy, and in the optimized diet (OD) group, this treatment was associated with a diet plan. The sample consisted of 60 subjects; 32 (53%) were treated in the non-optimized diet group (ND group) and 28 (47%) in the OD group. In both groups, the periodontal treatment significantly improved the recorded periodontal outcomes between T0 and T1 (FMPS, FMBS, CAL, PPD). Inter-group differences were not statistically significant (p < 0.05). The linear regression models showed that the optimized diet was associated with a higher reduction in PPD and FMBS after the treatment, while patients who had higher LDL levels (over 100 mg/mL) had a less favorable improvement of PPD. The application of an improved diet plan can increase the reduction in PPD and FMBS after non-surgical periodontal therapy when compared with periodontal treatment alone.

Morphodynamic limits to environmental signal propagation across landscapes and into strata.

The sedimentary record contains unique information about landscape response to environmental forcing at timescales that far exceed landscape observations over human timescales. However, stochastic processes can overprint and shred evidence of environmental signals, such as sediment flux signals, and so inhibit their transfer to strata. Our community currently lacks a quantitative framework to differentiate between environmental signals and autogenic signals in field-scale analysis of strata. Here we develop a framework and workflow to estimate autogenic thresholds for ancient sediment routing systems. Crucially these thresholds can be approximated using measurements that are readily attainable from field systems, circumventing the low temporal resolution offered by strata. This work demonstrates how short-term system dynamics can be accessed from ancient sediment routing systems to place morphodynamic limits on environmental signal propagation across ancient landscapes and into strata.

Analysis of Proximal Contact Loss Between Implant Restorations and Adjacent Teeth: A 10-Year Retrospective Study.

Restoring the proximal contacts is important for a restoration's long-term success. A frequently observed late complication of implant restoration is proximal contact loss. At present, there is a lack of sufficient research for determining the prevalence of proximal contact loss and for identifying the causative factors. The purpose of this clinical retrospective study was to evaluate the prevalence of proximal contact loss between implant restorations and adjacent teeth and to identify the causative factors. Partially edentulous patients who had received single crowns or fixed dental prostheses on implants were selected; the rehabilitations were metal-ceramic or all-ceramic, screw- or cement-retained. The primary study outcome was clinical evaluation of mesial and distal proximal contact tightness. The secondary outcome was evaluation of patient awareness of proximal contact loss, food impaction, and occurrence of biologic complications. In total, 237 single crowns and 83 fixed partial dentures were assessed. A multivariate logistic regression model was adopted. The overall prevalence of proximal contact loss was 51%. Among the patients with proximal contact loss, 107 (65%) were aware of its presence, while 58 (35%) reported food impaction. Within the limits of the present study, proximal contact loss between implant prostheses and adjacent teeth can be considered a frequent event, even at a 10-year follow-up, that should be carefully considered and monitored by patients and operators.

The effect of soft tissue augmentation on the clinical and radiographical outcomes following immediate implant placement and provisionalization: a systematic review and meta-analysis.

BACKGROUND: Nowadays, due to the esthetic and social demands of patients, conventional staged protocols seem to be increasingly replaced by faster, one-step protocols. The purpose of the present systematic review is to assess the peri-implant soft tissue changes after immediate implant placement and provisionalization (IIPP) comparing patients treated with or without a sub-epithelial connective tissue graft (SCTG) when replacing a single tooth in the esthetic region. METHODS: The present systematic review was written following the PRISMA checklist. Immediate implants placed with a connective tissue graft and without one were compared. The researched primary outcomes were the mid-buccal mucosa level (MBML) facial soft tissue thickness (FSTT) and marginal bone loss (MBL). The weighted mean differences (WMD) were estimated for all three outcomes. RESULTS: The change in the mid-buccal mucosa level in the intervention group was significantly higher (WMD 0.54; 95% CI 0.33-0.75), with no indication of heterogeneity (I2 = 16%). The facial soft tissue thickness increased significantly in the intervention group (WMD 0.79; 95% CI 0.37-1.22). The marginal bone loss was significantly higher in the control group (WMD 0.13; 95% CI 0.07-0.18), with no indication of heterogeneity (I2 = 0%). CONCLUSIONS: The results of the meta-analyses showed a statistically significant reduced change of the marginal bone loss and vestibular recession, as well as higher soft tissue thickness, when a graft was used. The included studies had a short observation time; therefore, studies with longer follow-ups are needed to confirm these findings.

The Effect of Controlled Diabetes and Hyperglycemia on Implant Placement with Simultaneous Horizontal Guided Bone Regeneration: A Clinical Retrospective Analysis.

Diabetes represents a challenge in implant therapy because hyperglycemia may negatively affect bone regeneration, directly compromising clinical outcomes and increasing clinical failures. The aim of this retrospective study is to analyse the prognostic significance of HbA1c levels in patients undergoing implant placement associated with horizontal guided bone regeneration. Thirty-four patients were divided into 3 groups according to their HbA1c levels: nondiabetic normoglycemic patients (HbA1c < 5.7%), nondiabetic hyperglycemic patients (HbA1c < 6.5%), and controlled diabetic patients (HbA1c < 7%). Primary outcomes were dimensional changes in height (VDH) and width (DW) of the peri-implant defect. Secondary outcomes were evaluations of periodontal parameters of adjacent tooth sites, wound healing, marginal bone loss (MBL), and survival and success rates. At T 1 (6 months), mean VDH values in groups 1, 2, and 3 were, respectively, 0.07, 0.5, and 0.25 mm. Mean DW values in those same groups were, respectively, 0.07, 0.38, and 0.33 mm. HbA1c levels were not statistically related to VDH and DW values at T 1. No statistically significant differences were observed in MBL between groups (p = 0.230). Implant survival and success rates were, respectively, 98% and 96%. Simultaneous guided bone regeneration is a feasible procedure for the treatment of horizontal bone deficiencies in controlled diabetic patients.

Technical and Biological Complications of Screw-Retained (CAD/CAM) Monolithic and Partial Veneer Zirconia for Fixed Dental Prostheses on Posterior Implants Using a Digital Workflow: A 3-Year Cross-Sectional Retrospective Study.

OBJECTIVE: The introduction of CAD/CAM and the development of zirconia-based restorations have allowed clinicians to use less expensive materials and faster manufacturing procedures. The purpose of the study was to analyze the differences, in terms of mechanical and biological complication, in multiunit zirconia fixed dental prosthesis (FPDs) on posterior implants produced using a digital workflow. Method and Materials. This study was a retrospective investigation, and patients treated with screw-retained monolithic or partial veneer FPDs on dental implants were selected. Periapical radiographs were taken at baseline and at the 3-year follow-up. Complications were recorded and classified as technical and biological ones. RESULTS: The study population included 25 patients. The occlusal and interproximal corrections were not clinically significant. In the study sample, the survival rate and success rate of the FPDs after 3 years were 100% and 96%, respectively. One implant failed immediately after placement. CONCLUSION: Monolithic zirconia FPDs and partial veneer FPDs showed a 100% survival rate, presenting an interesting alternative to metal ceramic restorations. The partial veneer FPDs had a higher technical complication rate than the monolithic FPDs; however, no statistically significant difference was found.

Patient Satisfaction with Implant-Supported Monolithic and Partially Veneered Zirconia Restorations.

The digital workflow and the application of Computer-Aided Manufacturing (CAM) to prosthodontics present the clinician with the possibility of adopting new materials that confer several advantages. Especially in the case of zirconia, these innovations have profoundly changed daily practice. This paper compares the satisfaction and perception of patients who received implant-supported single crowns (SC) and fixed partial dentures (FPD) made from zirconia, either monolithic or partially veneered, after 3 years of follow-up; the success and survival rate of these restorations were also measured. Forty patients, who had been previously treated with implant-supported SC or FPD, either monolithic or partially veneered, and submitted to a yearly maintenance program, were recalled 3 years after their treatment and requested to complete an 8-question questionnaire regarding their perceptions of the treatment. Any mechanical or biological complication that had occurred from the time of delivery was also recorded. Patients that experienced ≥1 complication were less likely to be prone to repeat the treatment. The 3-year success rate was 92.6% for monolithic restoration and 92.3% for partially veneered restoration, while the survival rate was 100% for both restorations. The 3-year follow-up found that monolithic and partially veneered zirconia restorations are both well-accepted treatment options, and patients preferred the veneered restorations (0.76, p < 0.05) from an aesthetic point of view. According to our results, monolithic and veneered zirconia restorations are both reliable treatment options and are both equally accepted by patients.

Influence of Immediate Implant Placement and Provisionalization with or without Soft Tissue Augmentation on Hard and Soft Tissues in the Esthetic Zone: A One-Year Retrospective Study.

The purpose of this clinical research was to evaluate peri-implant marginal changes around immediate implants placed either with the application of SCTG or XCM or without soft tissue grafting. A total of 48 patients requiring a single implant-supported restoration in the anterior jaw were selected for inclusion. Three surgical procedures were performed, as follows: type 1 implant with subepithelial connective tissue graft (SCTG), type 1 implant with xenogenic collagen matrix (XCM), and type 1 implant without soft tissue augmentation (NG) (control group). The marginal change of peri-implant soft tissue, facial soft tissue thickness (FSTT), peri-implant health status, esthetics, and patient satisfaction were assessed at one year after surgery. All of the placed implants showed a survival rate of 100%. No significant differences in FSTT were recorded between the SCTG group and the XCM group after treatment (P > 0.05), while the NG group presented a significant difference (P < 0.05). Patients in the NG group lost significantly more in the buccal marginal level than did patients in the SCTG group and those in the XCM group (P < 0.05). The favourable success rate recorded in all groups confirmed immediate tooth replacement as a choice of treatment for a missing anterior single tooth. The NG group presented significant changes of FSTT and buccal marginal level, while XCM constituted a viable alternative to SCTG.

Patient and Operator Centered Outcomes in Implant Dentistry: Comparison between Fully Digital and Conventional Workflow for Single Crown and Three-Unit Fixed-Bridge.

BACKGROUND: Scientific information about the effects of implant therapy following a precise workflow and patient and operators' preferences should be considered to choose which implant treatment protocol to use, and to achieve patient's satisfaction and functional results. The aim of this study was to analyze implant rehabilitations with a fully digital workflow and compare this approach with a conventional one. METHODS: This study comprises 64 patients treated with a fully digital approach and 58 patients treated using a conventional protocol. Patient and operator centered outcomes were assessed through two visual analogue scale (VAS) questionnaires. RESULTS: The VAS questionnaire demonstrated better results for the digital workflow concerning anxiety, convenience, taste, nausea sensation, pain and breathing difficulties (p < 0.0001). The VAS questionnaire administered to the operators showed better scores for the digital approach in relation to anxiety, convenience, difficulties of the impression procedure and the workflow (p < 0.0001). A significant reduced mean time for the digital workflow as well as a reduced number of required visits were recorded. CONCLUSION: The analysis of a fully digital and a conventional protocol showed better results according to patient and operators' preferences when a fully digital approach was used.

Monolithic CAD-CAM lithium disilicate versus monolithic CAD-CAM zirconia for single implant-supported posterior crowns using a digital workflow: A 3-year cross-sectional retrospective study.

STATEMENT OF PROBLEM: Dentistry has evolved significantly with the introduction of digital technologies and materials; however, clinical evidence for the performance of the complete digital workflow for single implant-supported posterior crowns is lacking. PURPOSE: The purpose of this cross-sectional retrospective clinical study was to compare the clinical outcomes of 2 types of implant-supported crown used to replace a single missing posterior tooth in a completely digital workflow: transocclusal screw-retained monolithic lithium disilicate crowns versus transocclusal screw-retained monolithic zirconia crowns. MATERIAL AND METHODS: A total of 38 participants who had been provided with dental implants and transocclusal screw-retained monolithic lithium disilicate or zirconia single crowns were evaluated in the study. Clinical and esthetic outcomes were recorded after a 3-year follow-up. RESULTS: Both groups had comparable clinical outcomes with a survival rate of 100%. In the lithium disilicate group, 89% of the participants were free of technical complications, and 95%, in the zirconia group. Only 1 patient experienced minor chipping affecting a lithium disilicate crown. All complications were considered minor and were easily resolved, and none of the participants required replacement of a crown. No biological complications were recorded in either group. CONCLUSIONS: Within the limitations of this cross-sectional retrospective clinical study, monolithic lithium disilicate and zirconia screw-retained single crowns fabricated using computer-aided design and computer-aided manufacturing (CAD-CAM) and a fully digital workflow were found to be reliable and suitable clinical options for restoring a posterior missing tooth on a dental implant.

Hard and Soft Tissue Evaluation of Different Socket Preservation Procedures Using Leukocyte and Platelet-Rich Fibrin: A Retrospective Clinical and Volumetric Analysis.

PURPOSE: The extraction of a tooth is followed by hard and soft tissue changes that can compromise implant placement. The aim of the present retrospective study was to compare the clinical and radiographic outcomes of different ridge preservation procedures based on the use of leukocyte and platelet-rich fibrin (L-PRF). MATERIALS AND METHODS: The study population consisted of all patients who had undergone surgery from January 1, 2017 to January 1, 2018 for alveolar ridge preservation on single posterior teeth using 3 clinical protocols: L-PRF alone, L-PRF mixed with a bone xenograft, and bone xenograft alone. Clinical and radiographic measures were recorded preoperatively and at 6 months postoperatively to determine the horizontal and vertical ridge resorption. RESULTS: A total of 45 patients were included in the present study. All the surgeries were performed successfully, and no intraoperative complications developed. The L-PRF group experienced significantly greater horizontal and vertical bone resorption. The L-PRF plus bone xenograft group had less vertical and horizontal bone resorption than the bone xenograft alone group. Statistically significant differences in postoperative pain and wound healing were observed, with the bone xenograft alone group, in particular, having higher values for pain and experiencing delayed wound healing. CONCLUSIONS: Within the limitations of the present retrospective study, the use of a bone xenograft alone or L-PRF combined with a bone xenograft to perform alveolar ridge preservation procedures significantly limited bone resorption.

Seismic and experimental insights into eruption precursors at Volcán de Colima.

We combine geophysical and experimental observations to interpret preeruptive unrest at Volcán de Colima in 1998. 17,893 volcanic earthquakes were detected between 1 October and 31 December 1998, including 504 clusters. Using seismic ambient noise interferometry, we observe a drop in velocity prior to the eruption linked to damage accumulation during magma ascent. This is supported by experimental observations where static stress causes a velocity decrease prior to failure. Furthermore, we observe acoustic emission clusters during the experiments, with lower porosity samples producing higher numbers of repeaters. This behavior introduces tensile failure as an additional viable mechanism for clusters during magma ascent. The findings suggest that preeruptive magma ascent may be monitored to variable degrees of accuracy via descriptions of damage accumulation and associated seismic velocity changes.