Τετάρτη 8 Ιουνίου 2022

Comparative clinical study of conventional dental implant and mini dental implant‐retained mandibular overdenture: A 5‐ to 8‐Year prospective clinical outcomes in a previous randomized clinical trial

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Abstract

Aim

To compare the long-term prospective clinical outcomes in a previous randomized controlled clinical trial (RCT) of 2 Mini Dental Implant (2MDI), 4 Mini Dental Implant (4MDI), and 2 Conventional Dental Implant (2CDI)-retained mandibular overdenture with follow-up between 5 to 8 years.

Materials and Methods

Thirty-seven patients formerly participated in the Comparative Clinical Study of CDI and MDI for Mandibular Overdenture were requested for examination of clinical outcomes. A total of 104 implants were placed with mean follow-up periods 6.64 ± 0.60 years. In Group 1 (2MDI) and Group 2 (4MDI), implants were placed and immediately loaded with Equator® attachments to retained mandibular overdenture. In Group 3 (2CDI), implants were placed and delayed 3 months for denture loading with ball attachment. The success rate, survival rate, clinical implant performance scale (CIP scale), peri-implant tissue status, prosthetic complication, implant stability quotient (ISQ), marginal bone level change (MBLC), and patient satisfactions were analyzed.

Results

After 5 to 8 years follow-up, the success rate in Groups 1, 2, and 3 were 90.91%, 93.33%, and 54.55%, respectively. The success rate in Group 3 was significantly lesser than Group 1 (p = 0.016) and Group 2 (p < 0.001). The survival rate in Groups 1, 2, and 3 was 100%, 96.67%, and 90.91%, respectively, and showed no significant differences. Mean ISQ reported no significant differences between groups. Mean MBLC were 0.57 ± 1.19 mm, 0.68 ± 0.90 mm, and 1.55 ± 1.60 mm in Groups 1, 2, and 3, respectively. Group 3 reported significantly greater mean MBLC than Group 1 (p = 0.016) and Group 2 (p = 0.011), but Groups 1 and 2 were not significantly differences. The overall patient satisfactions were reported as not significant differences between groups.

Conclude

Two MDI-retained mandibular overdentures with immediate loaded protocol performed had favorable clinical outcomes, cost effectiveness, and overall patient satisfactions after 5 to 8 years follow-up.

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Influence of bone morphology on the mechanobiological stimuli distribution of maxillary anterior labial bone: A biomechanical study

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Abstract

Objective

This study intended to ascertain the dimensional effects of labial bone thickness and height on the mechanobiological stimuli distribution of maxillary anterior labial bone through biomechanical analysis.

Material and methods

Twelve 3D finite element models of an anterior maxillary region with an implant were computer-simulated, including four levels of labial bone thicknesses (2, 1.5, 1.0, and 0.5 mm) and three levels of labial bone heights (normal, reduced by 1/3, reduced by 1/2). A 45° buccolingual oblique load of 100 N was applied to the implant restoration.

Results

Equivalent stress and principal strain mainly concentrated on crestal bone around the implant neck. The maximum equivalent stress in bone decreased as labial bone mass decreased, while the maximum principal strain and the displacement of dental implant increased as labial bone mass decreased. No significant difference of these three indicators was observed, when the labial bone thickness changed in the range of 2.0–1.0 mm with sufficient labial bone height.

Conclusions

In terms of biomechanics, the thickness of labial bone plate was recommended ≥1 mm. Sufficient labial bone height was warranted to prevent the stability of the implants from being seriously affected. The labial bone heights were more effective than thicknesses on the mechanobiological stimuli response of the dental implant-bone system.

Clinical significance

For this 3D finite element study, the biomechanical responses under different bone mass conditions were explored, in order to predict the process of bone remodeling and provide valid clinical recommendations for the decision-making process regarding the choices of tissue augmentation for some specific esthetic implantation cases for future clinical applications.

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In Vitro Analysis of Shear Stress: CAD Milled vs Printed Denture Base Resins with Bonded Denture Tooth

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Abstract

Purpose

: As the fabrication of computer-aided design (CAD) milled and 3D printed denture base resins with bonded denture teeth increase in popularity, there is a need for research comparing the shear bond stress of milled and printed denture base resins with bonded denture teeth to that of a conventional heat processed denture base.

Materials and methods

: Denture base resin specimens (n = 9) were fabricated according to manufacturers' instructions using a novel test design. Two milled (Ivobase CAD PMMA, Ivoclar Vivadent and Polident PMMA, Polident Dental) and two 3D printed (Denture Base LP Resin, Formlabs and Lucitone Digital Print, Dentsply Sirona) materials were used. Conventional heat processed polymethylmethacrylate was used as the control (Lucitone 199, Dentsply Sirona, USA). Denture teeth (VITA Vitapan XL T44, #8, VITA Zahnfabrik) were bonded to their respective bases using denture tooth bonding agent (Ivobase CAD bonding system, Ivoclar). Specimens were aged in water for 600 hours at 37˚C and loaded until failure in a Universal testing machine. Shear bond stress was calculated. All specimens were evaluated for mode of failure and select specimens under scanning electron microscope and vertical scanning interferometry. Data were analyzed with one-way ANOVA followed by Tukey test (IBM SPSS) and fracture analysis performe d.

Results

: Shear stress was highest for the heat processed control (mean = 180 N ±26.76) and Polident test groups (mean = 180 N ±34.90). Milled specimens were not significantly different from the control (p = 0.076 for IvoBase CAD and 1.00 for Polident), while the printed groups were significantly different from the control (p = 0.012 for Formlabs Denture Base Resin and p = 000 for Carbon Lucitone Digital Print). Milled denture base resins perform similarly to heat processed denture base resin and better than 3D printed denture bases.

Conclusion

: For complete denture wearers, all resin materials used in this study may be clinically acceptable, as the sheer stress for all groups was higher than the reported maximum biting force of complete denture patients. However, for implant retained prostheses, the incorporation of additional retentive features should be considered when bonding denture teeth to printed bases. More research is needed to evaluate methods to increase the bond strength of denture teeth to printed denture base resins.

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Reverse Liver Spleen Uptake on [68Ga]Ga-PSMA-11 PET/CT

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imageAn 80-year-old man underwent [68Ga]Ga-PSMA-11 PET/CT for staging of high-risk prostate cancer. Homogeneously increased liver uptake, more than 3-fold the splenic uptake, was seen. There was no hepatic lesion evident on CT. A higher liver to splenic uptake is more typical of some 18F-labeled PSMA PET/CT but unusual in 68Ga-labeled PSMA PET/CT scan. Further evaluation revealed a history of impaired renal function, bilateral renal atrophy, relatively decreased renal uptake of [68Ga]Ga-PSMA-11, and prominent bowel activity. We concluded that impaired renal function and subsequent poor excretion resulted in increased hepatic excretion, hence the unusual increased homogeneous hepatic uptake.
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Investigational PET tracers in neuro-oncology—What’s on the horizon? A report of the PET/RANO group

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Abstract
Many studies in patients with brain tumors evaluating innovative PET tracers have been published in recent years, and the initial results are promising. Here, the Response Assessment in Neuro-Oncology (RANO) PET working group provides an overview of the literature on novel investigational PET tracers for brain tumor patients. Furthermore, newer indications of more established PET tracers for the evaluation of glucose metabolism, amino acid transport, hypoxia, cell proliferation, and others are also discussed. Based on the preliminary findings, these novel investigational PET tracers should be further evaluated considering their promising potential. In particular, novel PET probes for imaging of translocator protein and somatostatin receptor overexpression as well as for immune system reactions appear to be of additional clinical value for tumor delineation and therapy monitoring. Progress in developing these radiotracers may contribute to improvi ng brain tumor diagnostics and advancing clinical translational research.
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T cell epitopes are largely conserved in the SARS‐CoV‐2 Omicron subvariant (BA.1, BA.2, BA.3 and GKA)

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Abstract

The SARS-CoV-2 variant Omicron (B.1.1.529) was first reported in South Africa by the World Health Organization (WHO) in November 2021 and the Omicron variant is now the predominant globally prevalent variant and account for almost all sequences recently reported to GISAID1.

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SARS‐CoV‐2and Mutation RT‐qPCR Test Positivity Correlation with ABO and Rh Blood Types

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ABSTRACT

Introduction

Studies show that there may be a relationship between ABO blood type and SARS-CoV-2transmission. It was aimed to determine by investigating the blood type of patients whose one-step reverse transcription and real-time polymerase chain reaction (RT-qPCR) test was positive for Sars-CoV-2.

Materials and Methods

ABO and Rh blood type of individuals whose RT-qPCR test was positive for SARS-CoV-2were examined and an evaluation was made to identify whether there was a relationship between them or not.

Results

The blood type data of 44.928 SARS-CoV-2positive RT-qPCR test results has been obtained. 17.656 (39.29%) were delta, 8048 (17.91%) were alpha, 800 (1.78%) were beta and 3000 (6.67%) were omicrons while 15.424 (34.33%) SARS-CoV-2positive mutation was found to be negative.

Discussion

Our study suggests that O and Rh (-) blood types may provide protection against delta, AB and Rh (+) blood types may hinder omicron infection while A and Rh (+) blood types may be more vulnerable to alpha and delta while B and Rh (+) are more sensitive to beta mutation.

Conclusion

Molecular mechanism underlying the relationship between blood types and SARS-CoV-2infection needs further molecular studies and multi-centered studies.

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