Purpose
To compare the accuracy of digital and conventional impression techniques for completely edentulous patients and to determine the effect of different variables on the accuracy outcomes.
...Materials and methods
A stone cast of an edentulous mandible with five implants was fabricated to serve as master cast (control) for both implant‐ and abutment‐level impressions. Digital impressions (n = 10) were taken with an intraoral optical scanner (TRIOS, 3shape, Denmark) after connecting polymer scan bodies. For the conventional polyether impressions of the master cast, a splinted and a non‐splinted technique were used for implant‐level and abutment‐level impressions (4 cast groups, n = 10 each). Master casts and conventional impression casts were digitized with an extraoral high‐resolution scanner (IScan D103i, Imetric, Courgenay, Switzerland) to obtain digital volumes. Standard tessellation language (STL) datasets from the five groups of digital and conventional impressions were superimposed with the STL dataset from the master cast to assess the 3D (global) deviations. To compare the master cast with digital and conventional impressions at the implant level, analysis of variance (ANOVA) and Scheffe's post hoc test was used, while Wilcoxon's rank‐sum test was used for testing the difference between abutment‐level conventional impressions.
Results
Significant 3D deviations (P < 0.001) were found between Group II (non‐splinted, implant level) and control. No significant differences were found between Groups I (splinted, implant level), III (digital, implant level), IV (splinted, abutment level), and V (non‐splinted, abutment level) compared with the control. Implant angulation up to 15° did not affect the 3D accuracy of implant impressions (P > 0.001).
Conclusion
Digital implant impressions are as accurate as conventional implant impressions. The splinted, implant‐level impression technique is more accurate than the non‐splinted one for completely edentulous patients, whereas there was no difference in the accuracy at the abutment level. The implant angulation up to 15° did not affect the accuracy of implant impressions.
Prevention and management of peri‐implant disease Sun, Teresa Chanting; Chen, Chun‐Jung; Gallucci, German O.
Clinical implant dentistry and related research,
August 2023, 2023-Aug, 2023-08-00, 20230801, Letnik:
25, Številka:
4
Journal Article
Recenzirano
Background
As more patients choose dental implants as their primary treatment option to restore edentulous ridges or to replace compromised dentition, preventive strategies for peri‐implant diseases ...and complications have become an important topic.
Purpose
The aim of the review article is to summarize the current available evidence on the potential risk factors/indicators for peri‐implant disease development and then focus on the preventive strategies for peri‐implant diseases and conditions.
Materials and Methods
After reviewing the diagnostic criteria and the etiology of peri‐implant diseases and conditions, evidence on the possible associated risk factors/indicators for peri‐implant diseases were searched and identified. Recent studies were also surveyed to explore the preventive measures for peri‐implant diseases.
Results
The possible associated risk factors of peri‐implant diseases can be divided into the following categories: patient‐specific factors, implant‐specific factors, and long‐term factors. Patient‐specific factors such as history of periodontitis and smoking have been conclusively associated with peri‐implant diseases, whereas findings on others, such as diabetes and genetic factors, remain inconclusive. It has been suggested that both implant‐specific factors, such as implant position, soft tissue characteristics, and the type of connection used, and long‐term factors, such as poor plaque control and a lack of maintenance program, have a strong impact on maintaining the health of a dental implant. Assessment tool for evaluating the risk factors can be a potential preventive measure for peri‐implant disease prediction, and it is needed to be properly validated.
Conclusion
Proper maintenance program for early intervention to control peri‐implant diseases at the initial stage and pretreatment assessment of the potential risk factors is the best strategy to prevent implant diseases.
Abstract Statement of problem Limited evidence is available for the marginal and internal fit of fixed dental restorations fabricated with digital impressions compared with those fabricated with ...conventional impressions. Purpose The purpose of this systematic review was to compare marginal and internal fit of fixed dental restorations fabricated with digital techniques to those fabricated using conventional impression techniques and to determine the effect of different variables on the accuracy of fit. Material and methods Medline, Cochrane, and EMBASE databases were electronically searched and enriched by hand searches. Studies evaluating the fit of fixed dental restorations fabricated with digital and conventional impression techniques were identified. Pooled data were statistically analyzed, and factors affecting the accuracy of fit were identified, and their impact on accuracy of fit outcomes were assessed. Results Dental restorations fabricated with digital impression techniques exhibited similar marginal misfit to those fabricated with conventional impression techniques (P>.05). Both marginal and internal gaps were greater for stone die casts, whereas digital dies produced restorations with the smallest gaps ( P <.05). When a digital impression was used to generate stereolithographic (SLA)/polyurethane dies, misfit values were intermediate. The fabrication technique, the type of restoration, and the impression material had no effect on misfit values ( P >.05), whereas die and restoration materials were statistically associated ( P <.05). Conclusions Although conclusions were based mainly on in vitro studies, the digital impression technique provided better marginal and internal fit of fixed restorations than conventional techniques did.
To compare the accuracy of digital and conventional impression techniques for partially and completely edentulous patients and to determine the effect of different variables on the accuracy outcomes.
...An electronic and manual search was conducted to identify studies reporting on the accuracy of implant impressions. Pooled data were descriptively analyzed. Factors affecting the accuracy were identified, and their impact on accuracy outcomes was assessed.
The 76 studies that fulfilled the inclusion criteria featured 4 clinical studies and 72 in vitro studies. Studies were grouped according to edentulism; 41 reported on completely edentulous and 35 on partially edentulous patients. For completely edentulous patients, most in vitro studies and all three clinical studies demonstrated better accuracy with the splinted vs the nonsplinted technique (15 studies, splint; 1, nonsplint; 9, no difference). One clinical study and half of the in vitro studies reported better accuracy with the open-tray vs the closed-tray technique (10 studies, open-tray; 1, closed-tray; 10, no difference). For partially edentulous patients, one clinical study and most in vitro studies showed better accuracy with the splinted vs the nonsplinted technique (8 studies, splint; 2, nonsplint; 3, no difference). The majority of in vitro studies showed better accuracy with the open-tray vs the closed-tray technique (10 studies, open-tray; 1, closed-tray; 7, no difference), but the only clinical study reported no difference.
The splinted impression technique is more accurate for both partially and completely edentulous patients. The open-tray technique is more accurate than the closed-tray for completely edentulous patients, but for partially edentulous patients there seems to be no difference. The impression material (polyether or polyvinylsiloxane) has no effect on the accuracy. The implant angulation affects the accuracy of implant impressions, while there are insufficient studies for the effect of implant connection type. Further accuracy studies are needed regarding digital implant impressions.
Background
The treatment of mandibular edentulism with implant fixed complete dental prostheses (IFCDPs) is a routinely used treatment option.
Purpose
The study aims to report the implant and ...prosthodontic survival rates associated with IFCDPs for the edentulous mandible after an observation period of a minimum 5 years.
Materials and Methods
An electronic MEDLINE/PubMED search was conducted to identify randomized controlled clinical trials and prospective studies with IFCDPs for the edentulous mandible. Clinical studies with at least 5‐year follow‐up were selected. Pooled data were statistically analyzed and cumulative implant‐ and prosthesis survival rates were calculated by meta‐analysis, regression, and chi‐square statistics. Implant‐related and prosthesis‐related factors were identified and their impact on survival rates was assessed.
Results
Seventeen prospective studies, including 501 patients and 2,827 implants, were selected for meta‐analysis. The majority of the implants (88.5% of all placed implants) had been placed in the interforaminal area. Cumulative implant survival rates for rough surface ranged from 98.42% (95% confidence interval CI: 97.98–98.86) (5 years) to 96.86% (95% CI: 96.00–97.73) (10 years); smooth surface implant survival rates ranged from 98.93% (95% CI: 98.38–99.49) (5 years) to 97.88% (95% CI: 96.78–98.98) (10 years). The prosthodontic survival rates for 1‐piece IFCDPs ranged from 98.61% (95% CI: 97.80–99.43) (5 years) to 97.25% (95% CI: 95.66–98.86) (10 years).
Conclusion
Treatment with mandibular IFCDPs yields high implant and prosthodontic survival rates (more than 96% after 10 years). Rough surface implants exhibited cumulative survival rates similar to the smooth surface ones (p > .05) in the edentulous mandible. The number of supporting implants and the antero‐posterior implant distribution had no influence (p > .05) on the implant survival rate. The prosthetic design and veneering material, the retention type, and the loading protocol (delayed, early, and immediate) had no influence (p > .05) on the prosthodontic survival rates.
Dihydroorotase (DHOase) is the third enzyme in the de novo biosynthesis pathway for pyrimidine nucleotides, and an attractive target for potential anticancer chemotherapy. By screening plant extracts ...and performing GC-MS analysis, we identified and characterized that the potent anticancer drug plumbagin (PLU), isolated from the carnivorous plant
, was a competitive inhibitor of DHOase. We also solved the complexed crystal structure of yeast DHOase with PLU (PDB entry 7CA1), to determine the binding interactions and investigate the binding modes. Mutational and structural analyses indicated the binding of PLU to DHOase through loop-in mode, and this dynamic loop may serve as a drug target. PLU exhibited cytotoxicity on the survival, migration, and proliferation of 4T1 cells and induced apoptosis. These results provide structural insights that may facilitate the development of new inhibitors targeting DHOase, for further clinical anticancer chemotherapies.
Bisphenol A (BPA) is an estrogen‐like compound, and an environmental hormone, that is commonly used in daily life. Therefore, it may enter the human body through food or direct contact, causing BPA ...residues in blood and urine. Because most studies focused on the analysis of BPA in reproductive cells or tissues, regarding evidence the effect of BPA on human retinal pigment epithelium (ARPE‐19) cells unavailable. Accordingly, the present study explored the cytotoxicity of BPA on ARPE‐19 cells. After BPA treatment, the expression of Bcl‐XL an antiapoptotic protein, in the mitochondria decreased, and the expression of Bax, a proapoptotic protein increased. Then the mitochondrial membrane potential was affected. BPA changed in mitochondrial membrane potential led to the release of cytochrome C, which activated caspase‐9 to promote downstream caspase‐3 leading to cytotoxicity. The nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) and heme oxygenase 1 (HO‐1) pathway play a major role in age‐related macular degeneration. Our results showed that expression of HO‐1 and Nrf2 suppressed by BPA. Superoxide dismutase and catalase, which Nrf2 downstream antioxidants, were degraded by BPA. AMP‐activated kinase (AMPK), which can regulate the phosphorylation of Nrf2, and the phosphorylation of AMPK expression was reduced by BPA. Finally, BPA‐induced ROS generation and cytotoxicity were reduced by N‐acetyl‐l‐cysteine. Taken together, these results suggest that BPA induced ARPE‐19 cells via oxidative stress, which was associated with down regulated Nrf2/HO‐1 pathway, and the mitochondria dependent apoptotic signaling pathway.
Mitochondrial dysfunction, a common cellular hallmark in both familial and sporadic forms of Parkinson's disease (PD), is assumed to play a significant role in pathologic development and progression ...of the disease. Teaghrelin, a unique bioactive compound in some oolong tea varieties, has been demonstrated to protect SH‐SY5Y cells against 1‐methyl‐4‐phenylpyridinium induced neurotoxicity by binding to the ghrelin receptor to activate the AMPK/SIRT1/PGC‐1α pathway. In this study, an animal model was established using a neurotoxin, 1‐methyl‐4phenyl‐1,2,3,6‐tetrahydropyridine (MPTP), a byproduct of a prohibited drug, to evaluate the oral efficacy of teaghrelin on PD by monitoring motor dysfunction of mice in open field, pole, and bean walking tests. The results showed that MPTP‐induced motor dysfunction of mice was significantly attenuated by teaghrelin supplementation. Tyrosine hydroxylase and dopamine transporter protein were found reduced in the striatum and midbrain of MPTP‐treated mice, and significantly mitigated by teaghrelin supplementation. Furthermore, teaghrelin administration enhanced mitophagy and mitochondria biogenesis, which maintained cell homeostasis and prevented the accumulation of αSyn and apoptosis‐related proteins. It seemed that teaghrelin protected dopaminergic neurons in MPTP‐treated mice by increasing PINK1/Parkin‐mediated mitophagy and AMPK/SIRT1/PGC‐1α‐mediated mitochondria biogenesis, highlighting its potential therapeutic role in maintaining dopaminergic neurons function in PD. Mitochondrial dysfunction, a common cellular hallmark in both familial and sporadic forms of Parkinson's disease (PD), is assumed to play a significant role in pathologic development and progression of the disease. Teaghrelin, a unique bioactive compound in some oolong tea varieties, has been demonstrated to protect SH‐SY5Y cells against 1‐methyl‐4‐phenylpyridinium induced neurotoxicity by binding to the ghrelin receptor to activate the AMPK/SIRT1/PGC‐1α pathway. In this study, an animal model was established using a neurotoxin, 1‐methyl‐4phenyl‐1,2,3,6‐tetrahydropyridine (MPTP), a byproduct of a prohibited drug, to evaluate the oral efficacy of teaghrelin on PD by monitoring motor dysfunction of mice in open field, pole, and bean walking tests. The results showed that MPTP‐induced motor dysfunction of mice was significantly attenuated by teaghrelin supplementation. Tyrosine hydroxylase and dopamine transporter protein were found reduced in the striatum and midbrain of MPTP‐treated mice, and significantly mitigated by teaghrelin supplementation. Furthermore, teaghrelin administration enhanced mitophagy and mitochondria biogenesis, which maintained cell homeostasis and prevented the accumulation of αSyn and apoptosis‐related proteins. It seemed that teaghrelin protected dopaminergic neurons in MPTP‐treated mice by increasing PINK1/Parkin‐mediated mitophagy and AMPK/SIRT1/PGC‐1α‐mediated mitochondria biogenesis, highlighting its potential therapeutic role in maintaining dopaminergic neurons function in PD.
Blood–brain barrier (BBB) characteristics are induced and maintained by crosstalk between brain microvascular endothelial cells and neighboring cells. Using in vitro cell models, we previously found ...that a bystander effect was a cause for Japanese encephalitis‐associated endothelial barrier disruption. Brain astrocytes, which neighbor BBB endothelial cells, play roles in the maintenance of BBB integrity. By extending the scope of relevant studies, a potential mechanism has been shown that the activation of neighboring astrocytes could be a cause of disruption of endothelial barrier integrity during the course of Japanese encephalitis viral (JEV) infection. JEV‐infected astrocytes were found to release biologically active molecules that activated ubiquitin proteasome, degraded zonula occludens‐1 (ZO‐1) and claudin‐5, and disrupted endothelial barrier integrity in cultured brain microvascular endothelial cells. JEV infection caused astrocytes to release vascular endothelial growth factor (VEGF), interleukin‐6 (IL‐6), and matrix metalloproteinases (MMP‐2/MMP‐9). Our data demonstrated that VEGF and IL‐6 released by JEV‐infected astrocytes were critical for the proteasomal degradation of ZO‐1 and the accompanying disruption of endothelial barrier integrity through the activation of Janus kinase‐2 (Jak2)/signal transducer and activator of transcription‐3 (STAT3) signaling as well as the induction of ubiquitin–protein ligase E3 component, n‐recognin‐1 (Ubr 1) in endothelial cells. MMP‐induced endothelial barrier disruption was accompanied by MMP‐mediated proteolytic degradation of claudin‐5 and ubiquitin proteasome‐mediated degradation of ZO‐1 via extracellular VEGF release. Collectively, these data suggest that JEV infection could activate astrocytes and cause release of VEGF, IL‐6, and MMP‐2/MMP‐9, thereby contributing, in a concerted action, to the induction of Japanese encephalitis‐associated BBB breakdown. GLIA 2015;63:1915–1932
Main Points
JEV‐infected astrocytes disrupted endothelial barrier integrity.
JEV infection caused astrocytes to release MMP‐2/MMP‐9, IL‐6, and VEGF.
IL‐6 and VEGF activated Jak2/STAT3/Ubr 1 leading to ZO‐1 degradation and endothelial barrier disruption.
Objective
The objective of this study was to evaluate the dimensions of buccal bone and soft tissue at immediately placed implants over a 7‐year period.
Material and methods
Twenty‐four patients, ...that participated in a clinical prospective study and received implants immediately placed into extraction socket, were enrolled for this study. Residual bone defects were grafted with xenogenic bone substitute and covered by means of collagen membrane. Baseline examination included measurements of full‐mouth plaque and bleeding scores, width of keratinized mucosa, and dimensions of residual bone defects at the buccal aspect. Seven years after implant placement, full‐mouth plaque score, full‐mouth bleeding score, width of keratinized mucosa, and probing pocket depth were assessed and cone beam computed tomography images acquired. Dimensions of buccal bone and soft tissue were evaluated on the cross‐sectional cone beam computed tomography reconstructions. Differences between two time‐points were tested using the two‐sided t‐test. Correlation analysis was used to investigate the influence of baseline bone defect dimensions on the bone dimensions measured at the 7‐year follow‐up.
Results and conclusions
Fourteen patients attended the follow‐up examination. In five implants almost no buccal bone was detected, whereas in the remaining nine implants the buccal bone was found covering the rough implant surface. No correlation was found between initial bone defects and bone dimensions at the follow‐up examination. The sites without radiographically detectable buccal bone at the 7‐year control presented with 1 mm more apical mucosal level in comparison to implants with intact buccal bone.
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