An Arrhythmia Classification-Guided Segmentation Model for Electrocardiogram Delineation

Accurate delineation of key waveforms in an ECG is a critical initial step in extracting relevant features to support the diagnosis and treatment of heart conditions. Although deep learning based methods using a segmentation model to locate P, QRS and T waves have shown promising results, their ability to handle signals exhibiting arrhythmia remains unclear. In this study, we propose a novel approach that leverages a deep learning model to accurately delineate signals with a wide range of arrhythmia. Our approach involves training a segmentation model using a hybrid loss function that combines segmentation with the task of arrhythmia classification. In addition, we use a diverse training set containing various arrhythmia types, enabling our model to handle a wide range of challenging cases. Experimental results show that our model accurately delineates signals with a broad range of abnormal rhythm types, and the combined training with classification guidance can effectively reduce false positive P wave predictions, particularly during atrial fibrillation and atrial flutter. Furthermore, our proposed method shows competitive performance with previous delineation algorithms on the Lobachevsky University Database (LUDB)

Treatment concepts for the posterior maxilla and mandible: short implants versus long implants in augmented bone

The aim of this narrative review is to describe treatment options for the posterior regions of the mandible and the maxilla, comparing short implants vs. longer implants in an augmented bone. The dental literature was screened for treatment options enabling the placement of dental implants in posterior sites with a reduced vertical bone height in the maxilla and the mandible. Short dental implants have been increasingly used recently, providing a number of advantages including reduced patient morbidity, shorter treatment time, and lower costs. In the posterior maxilla, sinus elevation procedures were for long considered to be the gold standard using various bone substitute materials and rendering high implant survival rates. More recently, implants were even placed without any further use of bone substitute materials, but the long-term outcomes have yet to be documented. Vertical bone augmentation procedures in the mandible require a relatively high level of surgical skill and allow the placement of standard-length dental implants by the use of autogenous bone blocks. Both treatment options, short dental implants, and standard-length implants in combination with vertical bone augmentation procedures, appear to result in predictable outcomes in terms of implant survival rates. According to recent clinical studies comparing the therapeutic options of short implants vs. long implants in augmented bone, the use of short dental implants leads to a number of advantages for the patients and the clinician

Core Ossification of Bone Morphogenetic Protein-2-Loaded Collagenated Bone Mineral in the Sinus

The objective of this study was to investigate in vitro release kinetics and ossification patterns of bone morphogenetic protein-2-soaked collagenated porcine bone mineral (BMP-2/CPBM) in rabbit sinuses. Release kinetics of BMP-2/CPBM was determined in vitro up to 56 days. In 16 rabbits, BMP-2/CPBM (BMP group) and CPBM alone (control group) were bilaterally grafted in both sinuses. After 4 (N = 8) and 12 (N = 8) weeks, radiographic and histologic analyses were performed. Approximately 40% of BMP-2 was released from CPBM during 3 days in vitro; release maintained at a reduced level until day 56. In vivo, new bone formation in BMP group was dominant at the center and decreased toward the borders of the sinus, while it mainly possessed close to the sinus membrane and basal bone in control group. At the center, significantly more new bone was found in BMP group compared to control group at 4 weeks (29.14% vs. 16.50%; p < 0.05). The total augmented volume of BMP group was significantly greater than control group at 4 (370.13 mm$^{3}$ vs. 299.32 mm$^{3}$) and 12 (400.40 mm$^{3}$ vs. 290.10 mm$^{3}$) weeks (p < 0.05). In conclusion, BMP-2/CPBM demonstrated a core ossification with a greater augmented volume and new bone formation in the center of the sinus compared to CPBM alone. Impact statement The center of the augmented maxillary sinus tends to show a slower and inferior new bone formation compared to the sites near the sinus membrane and basal bone. In this study, bone morphogenetic protein-2 (BMP-2) loaded onto collagenated porcine bone mineral (CPBM) resulted in a greater augmented volume and new bone formation at the center of the grafted sinus compared to CPBM alone. Therefore, BMP-2-added CPBM in maxillary sinus augmentation may potentially be beneficial to the clinicians, in terms of accelerating the new bone formation at the center area where the apical half of the implant fixture usually places

Report of a human autopsy case in maxillary sinuses augmented using a synthetic bone substitute: Micro-computed tomographic and histologic observations

OBJECTIVE This study of a human autopsy case aimed to characterize the histologic and micro-computed tomographic results of maxillary sinus augmentation using a synthetic bone substitute and simultaneous implant placement at 6 years. MATERIAL AND METHODS This report is based on the whole-body donation of a 62-year-old male patient who died due to bladder cancer. Implants had been placed in conjunction with sinus augmentation using a mixture of biphasic calcium phosphate and autogenous bone into both maxillary sinuses 6 years prior to the body donation. The maxillary sinus areas containing implants were gently removed from the cadaver and scanned using high-resolution micro-computed tomography. Samples were sectioned, prepared for undecalcified histologic slides and stained with haematoxylin-eosin. RESULTS The augmented volume was observed up to the apex of the implants, which were successfully osseointegrated. Cross-sectional micro-computed tomographic views revealed that the bone-substitute particles were embedded in radiopaque-mineralized tissues showing a trabecular pattern around the implants. The histologic analysis revealed mature lamellar bone surrounding the remaining bone-substitute particles as well as well-organized bone marrow spaces in the augment bone area and around the dental implants. CONCLUSION This human autopsy study histologically confirmed the presence of successful bone formation and long-term volume stability after sinus augmentation using biphasic calcium phosphate and simultaneous implant placement

Radiographic and Histologic Analysis 1–2 Years after Alveolar Ridge Preservation in Maxillary Premolar and Molar: A Case Report

After tooth extraction, notable ridge alterations occur due to resorption of bundle bones during the healing process. In areas with thin or damaged socket walls and multiple adjacent tooth extraction, dimensional changes are more prominent in the marginal proportion. In addition to the marginal changes, upper molar teeth are also vulnerable to pneumatization of the maxillary sinus. To reduce dimensional changes in extraction sockets, alveolar ridge preservation (ARP) is favored by many clinicians in areas where a large amount of dimensional change is expected. This case report presents two cases of ARP using collagenated demineralized bovine bone mineral and demineralized porcine bone mineral in the apically involved upper premolar and molar, respectively. Implants were placed one and two years, respectively, after the ARP. Radiographic analyses of residual bone height and volume were measured using cone-beam-computed tomography (CBCT) and histologic analysis of newly formed mineralized bone and residual graft material percentages were measured from the collected tissue samples using a trephine bur. Implants were placed using a simple technique, without any additional bone grafts at the marginal proportion. The ARP technique could maintain the alveolar bone height and volume, as well as minimize the invasiveness of surgical procedures during implant surgery

Soft Tissue Dimensions Following Tooth Extraction in the Posterior Maxilla: A Randomized Clinical Trial Comparing Alveolar Ridge Preservation to Spontaneous Healing

Background: To assess the soft tissue dimension following tooth extraction and alveolar ridge preservation in the posterior maxilla compared to spontaneous healing. Methods: Thirty-five patients randomly assigned to alveolar ridge preservation (ARP) and spontaneous healing (SH) after maxillary molar extraction. The crestal, buccal, and palatal gingival thickness at 6 months was measured around virtually placed implant fixtures using superimposed cone-beam computed tomography and intraoral scan taken at 6 months. Buccal mucogingival junction (MGJ) level change over 6 months was estimated using intraoral scans obtained at suture-removal and 6 months. Results: The crestal gingiva was significantly thinner in group ARP (−1.16 mm) compared to group SH (p &lt; 0.05). The buccal and palatal gingiva was significantly thinner at the implant shoulder (IS) level in group ARP (buccal: −0.75 mm; palatal: −0.85 mm) compared to group SH (p &lt; 0.05). The thickness at 2 mm below the IS of both sides and the buccal MGJ level change were similar in both groups (p &gt; 0.05). Conclusions: ARP in the posterior maxilla resulted in a thinner soft tissue on top of and at the prospective level of the implant shoulder at 6 months. The buccal MGJ level changed minimal for 6 months in both groups

Distance of insertion points in a mattress suture from the wound margin for ideal primary closure in alveolar mucosa : an in vitro experimental study

Purpose: This study was conducted to determine how the distance of the near insertion points in a vertical mattress suture from the wound margin influences the pattern of primary closure in an in vitro experimental model. Methods: Pairs of 180 porcine gingival and alveolar mucosa samples were harvested from 90 pig jaws and fixed to a specially designed model. A vertical mattress suture was performed with the near insertion point at 3 different distances from the wound margin (1-, 3-, and 5-mm) on both the gingival and mucosal samples (6 groups; n=30 for each group). The margin discrepancy and the presence of epithelium between the wound margins were measured on histologic slides. Results: The margin discrepancy decreased significantly as the near insertion point became closer to the wound margin both in mucosal tissue (0.241 +/- 0.169 mm, 0.945 +/- 0.497 mm, and 1.306 +/- 0.773 mm for the 1-, 3-, and 5-mm groups, respectively) and in gingival tissue (0.373 +/- 0.304 mm, 0.698 +/- 0.431 mm, and 0.713 +/- 0.691 mm, respectively). The frequency of complications of wound margin adaptation reduced as the distance of the near insertion point from the wound margin decreased both in the mucosal and gingival tissues. Conclusions: Placing the near insertion point close to the wound margin enhances the precision of wound margin approximation/adaptation using a vertical mattress suture

Volume stability of the augmented sinus using a collagenated bovine bone mineral grafted in case of a perforated Schneiderian membrane: An experimental study in rabbits

Objectives: To determine the volume stability of a sinus augmented with a collagenated bovine bone mineral (CBBM) in case of an intact or perforated Schneiderian membrane (SM). Materials and methods: A bilateral sinus augmentation procedure was performed in eight rabbits. The SM was intentionally perforated in one side (SMP group), while it remained intact in contra-lateral side (control group) and the same amount of CBBM was then grafted. At 12 weeks, the animals were euthanized for radiographic and histomorphometric analyses. Results: The augmented volume did not differ significantly between the two groups: 262.2 ± 32.1 mm3 in SMP group and 261.9 ± 48.5 mm3 in the control group (p = .959). There was no significant difference in the total augmented area: 24.7 ± 5.2 mm2 in SMP group and 23.2 ± 2.9 mm2 in the control group (p = .773). The areas of newly formed bone also did not differ significantly between the two groups, but was significantly lower at the centre of the augmented region than in the region of the surgical window in both groups (p < .05). Conclusion: A perforation of the SM in a rabbit model does neither impact the augmented volume nor new bone formation following grafting of the sinus with a CBBM. Keywords: Schneiderian membrane; animal study; volume stability; xenograft. © 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Dimensional changes of the maxillary sinus augmented with a collagenated synthetic bone block or synthetic bone particulates: A pre-clinical study in rabbits

OBJECTIVE to compare the efficacy of a collagenated synthetic bone substitute (C-SBS) to a particulated synthetic bone substitute (P-SBS) in volume maintenance and new bone formations in a rabbit sinus model. MATERIALS AND METHODS Either C-SBS or P-SBS was grafted in both sinuses of 16 rabbits. Four (N = 8) or 12 (N = 8) weeks after the surgery, total augmented volume (TAV) and area (TAA), as well as new bone volume (NBV) and area (NBA), were statistically compared by radiographic and histomomertric analyses (p < 0.05). RESULTS The differences in TAV, NBV, TAA and NBA between C-SBS and P-SBS groups at 4 weeks were not statistically significant. The TAV (267.13 ± 62.08 vs. 200.18 ± 40.32 mm$^{3}$ ) and NBV (103.26 ± 10.50 vs. 71.10 ± 7.58 mm$^{3}$ ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < 0.05). The TAA (19.36 ± 2.88 vs. 14.48 ± 2.08 mm$^{2}$ ) and NBA (5.43 ± 1.20 vs. 3.76 ± 0.78 mm2) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < 0.05). CONCLUSIONS C-SBS grafted in rabbit sinuses demonstrated more favorable outcomes across all outcome measures compared to P-SBS at 12 weeks