Toothbrushing to address gingivitis

Background.—The toothbrush is the most widely used homecare method for controlling plaque, with a twice daily regimen commonly considered the best approach. The toothbrush achieves mechanical disruption, with fluoridated toothpastes used to address infectious agents and remineralization needs. A meta-review, which contains just systematic reviews, provides more evidence that separate empirical studies and is highly appropriate for determining if the current evidence base is complete or incomplete through a synthesis of the information. A meta-review was undertaken to summarize the contemporary synthesized evidence regarding the safety and efficacy of home mechanical plaque removal using a toothbrush to manage plaque and gingivitis. Methods.—The National Library of Medicine, the Cochrane Library, and the American Dental Association Center for Evidence-based Dentistry databases were searched to identify studies that satisfied the requirements for this meta-review. Plaque scores and gingivitis scores were the primary parameter, with safety considered as an important contributor to efficacy. The study also determined risk of bias and graded the evidence using the GRADE system. Results.—Ten evaluations were included in the review. Most of the systematic reviews were judged to have low to moderate risk of bias, with two having a substantial to high risk of bias. A meta-analysis was not done in view of the heterogeneity of the review

Clinical performance of CEREC AC Bluecam conservative ceramic restorations after five years—A retrospective study

OBJECTIVES: The aim of this study was to assess the clinical performance of CAD/CAM partial coverage posterior restorations made by CEREC AC Bluecam system after 5 years. METHODS: 159 ceramic partial coverage posterior restorations were placed in 109 patients in a private practice. The restorations were made using CEREC AC Bluecam with CEREC Blocs or Empress CAD blocks. The clinical performance of the restorations was evaluated with modified California Dental Association (CDA) guidelines, gingival and plaque indices, probing pocket depth, and bleeding on probing in a period of 5 years. Patients' satisfaction was assessed using visual analogue scale. The Kaplan-Meier method was used to analyze survival probability of the restorations (α=0.05). RESULTS: The restorations included 102CEREC Blocs and 57 Empress CAD. The survival rates of CEREC Blocs and Empress CAD blocks were 96.0% and 94.6%, respectively (P=0.67). A total of 7 (4.5%) failures were found. The failures were not significantly influenced by restoration size, type and position of teeth. The ceramic fracture was significantly more in nonvital teeth (P=0.04). The periodontal parameters were not significantly different between the restored and control teeth except plaque index. The mean score of patients' satisfaction was 94.4 ± 8.1. CONCLUSIONS: Chair-side CEREC AC ceramic partial coverage posterior restorations were clinically successful restorations with mean survival rate of 95.5% after 5 years. CLINICAL SIGNIFICANCE: Conservative chair-side CAD/CAM ceramic restorations with less reduction of tooth structure can be a successful restorative method with acceptable survival rate and patient's satisfaction

Effect of Surface Modification on Viability of L929 Cells on Zirconia Nanocomposite Substrat

Introduction: Zirconia bioceramic can be considered for metallic replacement in dental implant applications. A proper method of surface modification may promote better osseointegration.Methods: In study evaluated viability of fibroblast cell following surface treatment. Therefore, viability L929 cells were characterized using MTT assay and scanning electron microscopy.Results: The viability assessment determined significant differences A-Y-TZP20 without surface treatment as compared to laser surface treatment (B), laser surface treatment + hydroxyapatite-yttrium stabilized tetragonal zirconia nanocomposite coat (C) and control. This study demonstrated that L929 cells approximately proliferated and spread on A-Y-TZP20 nanocomposite disk in laser surface treatment(B), Laser surface treatment + hydroxiapatite-yttrium stabilized tetragonal zirconia nanocomposite coat (C) groups similar to control group.Conclusion: Laser surface treatment showed positive effect on the viability of L929 cells

The Effect of Vacuum Leak Rate on Sintering of Porous Titanium Scaffold

Titanium is a highly reactive metal and its high-temperature processing has to be done at a high-vacuum atmosphere. In this research, porous titanium scaffolds were fabricated using the space holder method for dental reconstruction purposes. Accordingly, the samples were sintered in two different vacuum furnaces at the vacuum level of 0.013 Pa, including high-vacuum leak rate (HLR) and low-vacuum leak rate (LLR). The microstructural study using the scanning electron microscope revealed that there was no significant difference in the microstructure of the samples. A compression test on the porous titanium scaffolds indicated that the HLR sample had less strength than the LLR sample. X-ray diffractometry also revealed that, besides the titanium peaks, the HLR sample included titanium oxide phases, unlike the LLR sample. Therefore, both vacuum chamber design and a vacuum leak rate of the furnace are parameters which are effective on the sintering of the porous titanium scaffold and should be considered

Current results and trends in platform switching

The platform switching (PLS) concept was introduced in the literature in 2005. The biological benefits and clinical effectiveness of the PLS technique have been established by several studies. In this article different aspects of PLS concept are discussed. Crestal bone loss, biologic width, and stress distribution in this concept are comprehensively reviewed. In this article the relative published articles from 1990 to 2011 have been evaluated by electronic search. Because of controversial results especially in immediate loading and animal studies, further modified research is needed to establish the mechanism and effect of the PLS technique. Essential changes in studies including using the control group for accurate interpretation of results and long-term observation, particularly through, randomized, prospective, multicenter trials with large numbers of participants, and implants are necessary

Effect of the processing cycle on dimensional changes of heat-polymerized denture base resins

Background: The second processing cycle for adding the artificial teeth to heat-polymerized acrylic resin denture bases may result in dimensional changes of the denture bases. The aim of this study was to evaluate the dimensional changes of the heat-polymerized acrylic resin denture bases with one and two-cycle processing methods. Materials and Methods: A metal edentulous maxillary arch was used for making 40 stone casts. Maxillary complete dentures were made with heat-polymerized acrylic resins (Meliodent and Acropars) with one and two stage processing methods (n = 10 for each group). Linear dimensional changes in anteroposterior and mediolateral distances and vertical changes in the first molar region were measured following each processing cycle, using a digital caliper. Mean percentage of the dimensional changes were subjected to two-way analysis of variance and Tukey honest significant difference tests (α = 0.05). Results: Postpolymerization contraction occurred in both anteroposterior and mediolateral directions in all studied groups; however, the vertical dimension was increased. Acropars acrylic resin showed the highest dimensional changes and the second processing cycle significantly affected the measured distances (P < 0.05). Meliodent acrylic resin was not significantly influenced by the processing method. Conclusion: Reheating of the acrylic resin denture bases for the addition of denture teeth result in linear dimensional changes, which can be clinically significant based on the acrylic resin used

Retentiveness of implant-supported metal copings using different luting agents

Background: With regard to potential retrievability of cement-retained implant restorations, the retentive strength of the luting agents is critical. The aim of this study was to evaluate the retention values of implant-supported metal copings using different luting agents. Materials and Methods: Twenty ITI implant analogs and solid abutments of 5.5-mm height were embedded vertically in autopolymerizing acrylic resin blocks. Metal copings with a loop on the occlusal surface were fabricated using base metal alloy (Rexillium III). The copings were luted using eight cements with different retention mechanisms (Panavia F2.0, Fuji Plus, Fleck′s, Poly F, Fuji I, Temp Bond, GC-free eugenol, and TempSpan) under static load of 5 kg (n=10). All specimens were incubated at 37°C for 24 hours, conditioned in artificial saliva for 7 days and thermocycled for 5000 cycles (5-55°C). The dislodging force was measured using a universal testing machine at a crosshead speed of 5 mm/min. Statistical analyses were performed using Kruskal-Wallis (α=0.05) and Mann-Whitney tests with Bonferroni correction (α=0.001). Results: Fuji Plus and TempSpan had the highest and the least mean retentive strength, respectively (320.97±161.47, 3.39±2.33). There was no significant difference between Fuji Plus, Fleck′s, Ploy F, and Panavia F2.0. These cements were superior to provisional cements and Fuji I (P<0.001) which showed statistically same retentive strength. Conclusion: Within the conditions of this study, the resin modified glass ionomer, zinc phosphate, zinc polycarboxylate, and Panavia F2.0 had statistically the same retentive quality and are recommended for definitive cementation of single implant-supported restorations. The provisional cements and glass ionomer may allow retrievability of these restorations

Lithium metasilicate glass-ceramic fabrication using spark plasma sintering

Background: The digital dentistry, requires materials with wo opposite properties of machining ability and also enough hardness. The main objective of this experimental study was to investigate the fabrication feasibility of the lithium metasilicate glass-ceramic in partially crystalized stated using the spark plasma sintering (SPS) method. Materials and Methods: In this study, SPS for the first time was used to fabricate primary lithium metasilicate glass-ceramic (LMGC) blocks. The raw materials were mixed and melted and then quenched in water and the resulted frits were grinded. The resulting powder was sintered by SPS at 660, 680, and 700°C. Results: Scanning Electron Microscope (SEM), X-ray diffraction (XRD), and Vicker's microhardness assay were used to evaluate the properties of samples. Statistical comparison of the obtained data was performed by ANOVA, followed by the post hoc test of Duncan. Microstructural studies by SEM and XRD showed that all samples were composed of lithium metasilicate phase in a glassy matrix. With increasing the sintering temperature, the number and size of lithium metasilicate particles increased and higher mechanical properties have been achieved. However, the sintered sample at 700°C has less processing ability than the samples sintered at 660 and 680°C. Conclusion: The optimum sintering temperature for glass frit consolidation was determined by SPS at 680°C

Risk of contamination of different areas of dentist′s face during dental practices

Background: Dental practice presents opportunities for cross-contamination. The dentist′s face is at high-risk of infection transmission. The purpose of this study was to evaluate the risk of contamination in different areas of dentist′s face during dental practices. Methods: The visible splashes of materials that accumulated on cellulose face shields during 144 prosthetics and periodontal procedures were evaluated. The splashes were detected on 14 areas (each 1 cm 2 ) of the dentist′s face including around nose, mouth, eyes, and zygoma by a magnifier (×2). One way Analysis of variance, Duncan and t-test were used for data analysis (α = 0.05). Results: Contamination of different areas of dentist′s face was significantly different (P < 0.05). The areas around nose and the inner corner of eyes were the most contaminated areas. Zygoma was the least contaminated area. The contaminated areas during periodontal treatments were significantly more than prosthetic treatments (P < 0.05). There was no significant difference between contamination on left and right sides of the face. Conclusions: During dental practice, central areas of the face such as inner part of the eyes and around the nose were most contaminated areas. These parts are the important areas for transmission of infection. It is recommended to use protective means like glasses, mask, and protective shield, which have more protection field in these areas

Marginal Accuracy of Lithium Disilicate Full‐Coverage Single Crowns Made by Direct and Indirect Digital or Conventional Workflows: A Systematic Review and Meta‐Analysis

Purpose Several studies have compared digital intraoral scanners and conventional impressions. The accuracy of these two methods in terms of marginal accuracy of lithium disilicate crowns is not well-established, yet. The purpose of this study was to systematically review available publications on marginal fit of single-unit, full-coverage, tooth-supported lithium disilicate restorations. Methods Pubmed, Web of Science, Cochrane, EMBASE, and Scopus were electronically searched along with a manual search. After critical appraisal, data from selected studies were extracted and mean marginal difference with a 95% confidence interval was calculated. Meta-analysis of the collected data was conducted using STATA software. Results The meta-analysis revealed similar marginal gap values in intraoral scanners with conventional groups (p>0.05) and in intraoral scanners with extraoral canners (p>0.05). Conclusion No significant difference was seen between digital and conventional impressions or intra- and extraoral scanners for marginal accuracy of lithium disilicate crowns