Open AccessReview
Oral Dysbiotic Communities and Their Implications in Systemic Diseases
Dent. J. 2018, 6(2), 10; doi:10.3390/dj6020010 -
Abstract
The human body supports the growth of a wide array of microbial communities in various niches such as the oral cavity, gastro-intestinal and urogenital tracts, and on the surface of the skin. These host associated microbial communities include yet-un-cultivable bacteria and are influenced
[...] Read more.
The human body supports the growth of a wide array of microbial communities in various niches such as the oral cavity, gastro-intestinal and urogenital tracts, and on the surface of the skin. These host associated microbial communities include yet-un-cultivable bacteria and are influenced by various factors. Together, these communities of bacteria are referred to as the human microbiome. Human oral microbiome consists of both symbionts and pathobionts. Deviation from symbiosis among the bacterial community leads to “dysbiosis”, a state of community disturbance. Dysbiosis occurs due to many confounding factors that predispose a shift in the composition and relative abundance of microbial communities. Dysbiotic communities have been a major cause for many microbiome related systemic infections. Such dysbiosis is directed by certain important pathogens called the “keystone pathogens”, which can modulate community microbiome variations. One such persistent infection is oral infection, mainly periodontitis, where a wide array of causal organisms have been implied to systemic infections such as cardio vascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer’s disease. The keystone pathogens co-occur with many yet-cultivable bacteria and their interactions lead to dysbiosis. This has been the focus of recent research. While immune evasion is one of the major modes that leads to dysbiosis, new processes and new virulence factors of bacteria have been shown to be involved in this important process that determines a disease or health state. This review focuses on such dysbiotic communities, their interactions, and their virulence factors that predispose the host to other systemic implications. Full article
Open AccessEditorial
The Strange Case of Peri-Implantology
Dent. J. 2018, 6(2), 9; doi:10.3390/dj6020009 -
Open AccessArticle
Laboratory Investigation Comparing Plaque Removal Efficacy of Two Novel-Design Toothbrushes with Different Brushing Techniques
Dent. J. 2018, 6(2), 8; doi:10.3390/dj6020008 -
Abstract
Manufacturers of manual toothbrushes have improved novel brush head designs aimed at achieving good plaque removal even with inadequate brushing technique. This study tested the plaque removal efficacy of two novel designs compared with a flat trimmed toothbrush with different brushing techniques. Two
[...] Read more.
Manufacturers of manual toothbrushes have improved novel brush head designs aimed at achieving good plaque removal even with inadequate brushing technique. This study tested the plaque removal efficacy of two novel designs compared with a flat trimmed toothbrush with different brushing techniques. Two novel-design toothbrushes (Colgate® 360° Surround and Oral-B® Pro-Health™ Clinical Pro-Flex) were tested. The control toothbrush was Butler® GUM 311. Artificial plaque was applied on artificial teeth. Brushing with the modified Bass and horizontal scrub technique was then performed independently. After brushing, the remaining plaque index and Proximal Marginal Index (PMI) were evaluated. With the same brushing technique, there was no statistically significant difference in the mean of the whole mouth plaque scores or PMI among the three different toothbrush designs with neither brushing techniques (p > 0.05). When a comparison was made between the mean PMI of the two brushing techniques in each toothbrush design, Colgate® showed no statistically significant difference with either brushing technique (p > 0.05), but Butler® and Oral-B® showed statistically significantly less PMI with modified Bass technique than with horizontal scrub technique (p < 0.05). No difference in the whole mouth plaque removal efficacy was found among the three different toothbrush designs with either brushing technique. Full article
Figures

Figure 1

Open AccessProject Report
The Use of Picture Cards to Elicit Postgraduate Dental Student Feedback
Dent. J. 2018, 6(2), 7; doi:10.3390/dj6020007 -
Abstract
The aim of this study was to elicit information about the use of picture cards to stimulate student feedback following a postgraduate dental course. Twenty-nine general dental practitioners (GDPs) volunteered for the study. Following an explanation of how this style of feedback worked,
[...] Read more.
The aim of this study was to elicit information about the use of picture cards to stimulate student feedback following a postgraduate dental course. Twenty-nine general dental practitioners (GDPs) volunteered for the study. Following an explanation of how this style of feedback worked, students were asked to choose a picture card from those available and use that image to stimulate their feedback. An independent interviewer introduced the topic and gathered comments in the form of qualitative data, generated by pre-formed questions. 93% (n = 26) questionnaires were completed and returned. 77% (n = 20) GDPs reported enjoying giving their feedback by ‘picture card’ technique; 83% (n = 20) reported this form of feedback stimulated their thoughts. Qualitative data were analysed thematically. Some GDPs felt the picture cards helped them formulate their feedback, others felt being able to give feedback to a third party they did not know was beneficial and giving feedback as a group was helpful. This novel approach of using picture cards to stimulate feedback was well received by these GDPs. A mixed result as to the value of this style of feedback was evident. A group feedback session facilitated by a stranger was considered to be a valuable approach to take. Full article
Figures

Figure 1

Open AccessArticle
Effect of Violet-Blue Light on Streptococcus mutans-Induced Enamel Demineralization
Dent. J. 2018, 6(2), 6; doi:10.3390/dj6020006 -
Abstract
Background: This in vitro study determined the effectiveness of violet-blue light (405 nm) on inhibiting Streptococcus mutans-induced enamel demineralization. Materials and Methods: S. mutans UA159 biofilm was grown on human enamel specimens for 13 h in 5% CO2 at 37 °C
[...] Read more.
Background: This in vitro study determined the effectiveness of violet-blue light (405 nm) on inhibiting Streptococcus mutans-induced enamel demineralization. Materials and Methods: S. mutans UA159 biofilm was grown on human enamel specimens for 13 h in 5% CO2 at 37 °C with/without 1% sucrose. Wet biofilm was treated twice daily with violet-blue light for five minutes over five days. A six-hour reincubation was included daily between treatments excluding the final day. Biofilms were harvested and colony forming units (CFU) were quantitated. Lesion depth (L) and mineral loss (∆Z) were quantified using transverse microradiography (TMR). Quantitative light-induced fluorescence Biluminator (QLF-D) was used to determine mean fluorescence loss. Data were analyzed using one-way analysis of variance (ANOVA) to compare differences in means. Results: The results demonstrated a significant reduction in CFUs between treated and non-treated groups grown with/without 1% sucrose. ∆Z was significantly reduced for specimens exposed to biofilms grown without sucrose with violet-blue light. There was only a trend on reduction of ∆Z with sucrose and with L on both groups. There were no differences in fluorescence-derived parameters between the groups. Conclusions: Within the limitations of the study, the results indicate that violet-blue light can serve as an adjunct prophylactic treatment for reducing S. mutans biofilm formation and enamel mineral loss. Full article
Figures

Figure 1

Open AccessEditorial
Restorative and Esthetic Dentistry—A Special Issue of the DentistryJournal
Dent. J. 2018, 6(1), 5; doi:10.3390/dj6010005 -
Abstract
Due to the development of dental materials and the esthetic requirements of patients, conservative restoration and esthetic dentistry is becoming more and more important.[...] Full article
Open AccessEditorial
Soft and Hard Tissue Regeneration—A Special Issue of Dentistry Journal
Dent. J. 2018, 6(1), 4; doi:10.3390/dj6010004 -
Abstract
This Special Issue entitled “Soft and Hard Tissue Regeneration” will cover both periodontal and implant therapies.[...] Full article
Open AccessEditorial
Acknowledgement to Reviewers of DentistryJournal in 2017
Dent. J. 2018, 6(1), 3; doi:10.3390/dj6010003 -
Abstract
Peer review is an essential part in the publication process, ensuring that Dentistry Journal maintains high quality standards for its published papers [...]
Full article
Open AccessArticle
Effectiveness of Oral Hygiene Instructions Given in Computer-Assisted Format versus a Self-Care Instructor
Dent. J. 2018, 6(1), 2; doi:10.3390/dj6010002 -
Abstract
Background: This randomized, single-blinded, controlled study compares the effectiveness of two modes of delivering the same set of oral hygiene instructions: those loaded on a computer-assisted teaching format versus those given personally by a self-care instructor. Methods: 60 participants with mild to moderate
[...] Read more.
Background: This randomized, single-blinded, controlled study compares the effectiveness of two modes of delivering the same set of oral hygiene instructions: those loaded on a computer-assisted teaching format versus those given personally by a self-care instructor. Methods: 60 participants with mild to moderate periodontitis were randomized to either the computer-teaching format or the self-care instructor. Plaque score and bleeding indices were assessed at baseline and at 4 week re-evaluation to compare the instructional modalities. Results: At baseline, there was no difference in the parameters between the two groups. At re-evaluation, all parameters were significantly improved compared to baseline; however, there was no difference between any parameters in the computer group versus the instructor. Plaque score was significantly different between younger and older participants, such that participants under 50 years old had lower plaque scores when they received instructions using the computer format (72.5 ± 12.6 vs. 87.2 ± 10.4; p < 0.001). Additionally, in those under-50 year olds, plaque scores were significantly better in the group using the computer format (87.2 ± 10.4 vs. 78.3 ± 15.6; p = 0.03). Conclusion: Computer teaching formats and self-care instructors are both effective means of communicating oral hygiene instructions. Computer-assisted instruction format effectiveness may amplify as the population ages. Applications of computer formats teaching oral hygiene instructions and cost effectiveness comparison studies warrant significant future investigation. Full article
Open AccessArticle
Autoimmune Diseases and Oral Health: 30-Year Follow-Up of a Swedish Cohort
Dent. J. 2018, 6(1), 1; doi:10.3390/dj6010001 -
Abstract
Oral infections up-regulate a number of systemic inflammatory reactions that, in turn, play a role in the development of systemic diseases. We investigated the association between oral health and autoimmune diseases in a cohort of Swedish adults. Hypothesis was that poor oral health
[...] Read more.
Oral infections up-regulate a number of systemic inflammatory reactions that, in turn, play a role in the development of systemic diseases. We investigated the association between oral health and autoimmune diseases in a cohort of Swedish adults. Hypothesis was that poor oral health associates with incidence of autoimmune diseases. Overall 1676 subjects aged 30–40 years old from Stockholm County (Sweden) participated in this study in 1985. Subjects were randomly selected from the registry file of Stockholm region and were followed-up for 30 years. Their hospital and open health care admissions (World Health Organization ICD 9 and 10 codes) were recorded from the Swedish national health registers. The association between the diagnosed autoimmune disease and the oral health variables were statistically analyzed. In all, 50 patients with autoimmune diagnoses were detected from the data. Plaque index was significantly higher in the autoimmune disease group (≥median 35 (70%) vs. ˂median 872 (54%), p = 0.030). No statistical difference was found in gingival index, calculus index, missing teeth, periodontal pockets, smoking or snuff use between patients with and without autoimmune disease. Our study hypothesis was partly confirmed. The result showed that subjects with a higher plaque index, marker of poor oral hygiene, were more likely to develop autoimmune diseases in 30 years. Full article
Open AccessArticle
Accuracy of Digitally Fabricated Wax Denture Bases and Conventional Completed Complete Dentures
Dent. J. 2017, 5(4), 36; doi:10.3390/dj5040036 -
Abstract
The purpose of this investigation was to analyze the accuracy of digitally fabricated wax trial dentures and conventionally finalized complete dentures in comparison to a surface tessellation language (STL)-dataset. A generated data set for the denture bases and the tooth sockets was used,
[...] Read more.
The purpose of this investigation was to analyze the accuracy of digitally fabricated wax trial dentures and conventionally finalized complete dentures in comparison to a surface tessellation language (STL)-dataset. A generated data set for the denture bases and the tooth sockets was used, converted into STL-format, and saved as reference. Five mandibular and 5 maxillary denture bases were milled from wax blanks and denture teeth were waxed into their tooth sockets. Each complete denture was checked on fit, waxed onto the dental cast, and digitized using an optical laboratory scanning device. The complete dentures were completed conventionally using the injection method, finished, and scanned. The resulting STL-datasets were exported into the three-dimensional (3D) software GOM Inspect. Each of the 5 mandibular and 5 maxillary complete dentures was aligned with the STL- and the wax trial denture dataset. Alignment was performed based on a best-fit algorithm. A three-dimensional analysis of the spatial divergences in x-, y- and z-axes was performed by the 3D software and visualized in a color-coded illustration. The mean positive and negative deviations between the datasets were calculated automatically. In a direct comparison between maxillary wax trial dentures and complete dentures, complete dentures showed higher deviations from the STL-dataset than the wax trial dentures. The deviations occurred in the area of the teeth as well as in the distal area of the denture bases. In contrast, the highest deviations in both the mandibular wax trial dentures and the mandibular complete dentures were observed in the distal area. The complete dentures showed higher deviations on the occlusal surfaces of the teeth compared to the wax dentures. Computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated wax dentures exhibited fewer deviations from the STL-reference than the complete dentures. The deviations were significantly greater in the vicinity of the denture teeth area and the bases. The conventional transfer of CAD/CAM-fabricated wax dentures into acrylic resin leads to the highest deviations from the STL-reference. Full article
Figures

Figure 1

Open AccessReview
PEEK with Reinforced Materials and Modifications for Dental Implant Applications
Dent. J. 2017, 5(4), 35; doi:10.3390/dj5040035 -
Abstract
Polyetheretherketone (PEEK) is a semi-crystalline linear polycyclic thermoplastic that has been proposed as a substitute for metals in biomaterials. PEEK can also be applied to dental implant materials as a superstructure, implant abutment, or implant body. This article summarizes the current research on
[...] Read more.
Polyetheretherketone (PEEK) is a semi-crystalline linear polycyclic thermoplastic that has been proposed as a substitute for metals in biomaterials. PEEK can also be applied to dental implant materials as a superstructure, implant abutment, or implant body. This article summarizes the current research on PEEK applications in dental implants, especially for the improvement of PEEK surface and body modifications. Although various benchmark reports on the reinforcement and surface modifications of PEEK are available, few clinical trials using PEEK for dental implant bodies have been published. Controlled clinical trials, especially for the use of PEEK in implant abutment and implant bodies, are necessary. Full article
Figures

Figure 1

Open AccessReview
The Use of Pit and Fissure Sealants—A Literature Review
Dent. J. 2017, 5(4), 34; doi:10.3390/dj5040034 -
Abstract
This paper reviews the literature and discusses the latest updates on the use of pit and fissure sealants. It demonstrates the effectiveness of pit and fissure sealants in preventing caries and the management of early carious lesions. It compares the use of different
[...] Read more.
This paper reviews the literature and discusses the latest updates on the use of pit and fissure sealants. It demonstrates the effectiveness of pit and fissure sealants in preventing caries and the management of early carious lesions. It compares the use of different sealant materials and their indications. It describes the application technique for sealants. It also reviews the cost-effectiveness of sealants as a preventive strategy. From this review and after the discussion of recently published studies on pit and fissure sealants, it is evident that sealants are effective in caries prevention and in preventing the progression of incipient lesions. It is therefore recommended that pit and fissure sealant be applied to high-caries-risk children for optimum cost-effectiveness. It is a highly sensitive technique that needs optimum isolation, cleaning of the tooth surface, etching, and the application of a thin bonding layer for maximum benefit. Recall and repair, when needed, are important to maximize the effectiveness of such sealant use. Full article
Figures

Figure 1

Open AccessCase Report
Colored Gingiva Composite Used for the Rehabilitation of Gingiva Recessions and Non-Carious Cervical Lesions
Dent. J. 2017, 5(4), 33; doi:10.3390/dj5040033 -
Abstract
In this case of extensive gingival recession (Miller’s Class II) and mild physiologic pigmentation, an alternative method for the placement of Amaris Gingiva-Colored Composite was used to produce a non-invasive, aesthetic result acceptable to the patient. In restoring the defects in the entire
[...] Read more.
In this case of extensive gingival recession (Miller’s Class II) and mild physiologic pigmentation, an alternative method for the placement of Amaris Gingiva-Colored Composite was used to produce a non-invasive, aesthetic result acceptable to the patient. In restoring the defects in the entire maxilla of this patient, the opaquers were not mixed, but applied individually, directly to various areas of the teeth. Multiple opaquers were placed in a pattern mimicking the coloring of the patient’s gingiva. These were then covered with the base shade for a more aesthetic result to the patient’s satisfaction. The restorations resulting from the alternative method were highly aesthetic and at an eleven (11) month review showed no signs of failure giving rise to the conclusion that this method proposed for application of Amaris Gingiva-Colored Composite is viable for producing highly-aesthetic restorations in cases of gingival recession. Full article
Figures

Figure 1

Open AccessCommunication
Effect of Decontamination and Cleaning on the Shear Bond Strength of High Translucency Zirconia
Dent. J. 2017, 5(4), 32; doi:10.3390/dj5040032 -
Abstract
(1) Background: This study evaluated the bonding performance of high translucency zirconia after diverse surficial decontamination and cleaning procedures. (2) Methods: High translucency zirconia (LavaTM Esthetic) specimens (2.0 mm × 20 mm × 10 mm) were exposed to different surface treatments prior
[...] Read more.
(1) Background: This study evaluated the bonding performance of high translucency zirconia after diverse surficial decontamination and cleaning procedures. (2) Methods: High translucency zirconia (LavaTM Esthetic) specimens (2.0 mm × 20 mm × 10 mm) were exposed to different surface treatments prior to bonding to CoCr cylinders (d = 5 mm, height = 3 mm). All surfaces were sandblasted (40 µm aluminum oxide, 2 bar) and treated with alcohol (al), saliva (s), saliva + water (sw), or saliva + NaOCl + water (sn) before bonding was performed with the following adhesive luting systems: RelyXTM Unicem 2 (RX), ScotchbondTM Universal (SBU) + RelyXTM Ultimate (RU) or Monobond Plus (MP) + Multilink® Automix (ML). After 24 h, thermocycling (TC:12,000 × 5 °C/55 °C) and 90 days of storage at 37 °C in distilled water, the shear bond strength (SBS) was evaluated according to ISO/TS 11,405:2015. Failure modes along bonding areas were characterized. Means and standard deviations (n = 10 per group) were determined and statistically analyzed with one-way ANOVA/Bonferroni (α = 0.05). (3) Results: The SBS after 24 h varied between 3.5 (sRX) and 69.4 MPa (snMP + ML). Values from 0 (sRX) to 70.3 MPa (swRX) were found after TC. Data after 90 days of storage showed the lowest values for sRX (0 MPa) and the highest values for alSBU + RU (75.5 MPa). Adhesive failure was noted at all aging conditions. (4) Conclusions: SBU + RU or RX and MP + ML including saliva decontamination of the ceramic surface with water or NaOCl + water allow efficient bonding to LavaTM Esthetic. Full article
Figures

Figure 1

Open AccessArticle
Polishing of Monolithic Zirconia Crowns—Results of Different Dental Practitioner Groups
Dent. J. 2017, 5(4), 30; doi:10.3390/dj5040030 -
Abstract
This pilot study evaluates the surface roughness of monolithic zirconia crowns after chairside polishing by different dental practitioner groups. Four practitioner groups (group I: dental clinical students (n = 6); group II: dentists < 2 years post-qualification experience (n = 6);
[...] Read more.
This pilot study evaluates the surface roughness of monolithic zirconia crowns after chairside polishing by different dental practitioner groups. Four practitioner groups (group I: dental clinical students (n = 6); group II: dentists < 2 years post-qualification experience (n = 6); group III: dentists > 2 years post-qualification experience (n = 6) and group IV: dental technicians (n = 6)) were asked to polish two CAD/CAM-fabricated full-contour zirconia crowns (48 in total). A two-step zirconia polishing kit was used in both trials. The first trial (T1) was conducted without a time limitation. In the second trial (T2), the polish was restricted to 15 seconds for each polisher. Two blinded investigators (I1 and I2) analyzed the surface roughness (Ra) before and after polishing (Alicona measuring system). No statistically significant difference in surface roughness was found between the polishing results of the dental practitioner groups. Major difference in surface finish was achieved by dental technicians, with a median value of 25.4 nm (interquartile range 10.15–35.26 nm) for I1 in T1. The lowest difference was achieved by dental students, with a median value of Ra = 6.72 nm (interquartile range 4.7–17.9 nm) in T1. In T2, experienced dentists showed the highest difference in surface finish, with a median value of 41.35 nm (interquartile range 7.77–54.11). No significant correlation was found between polishing time and polishing results. The polishing of monolithic zirconium dioxide crowns can be performed with the present polishing set directly chairside after occlusal adjustment, regardless of the practitioner’s experience level. Full article
Figures

Figure 1

Open AccessArticle
A Qualitative Evaluation of Clinical Audit in UK Dental Foundation Training
Dent. J. 2017, 5(4), 31; doi:10.3390/dj5040031 -
Abstract
Clinical Audit (CA) has been recognized as a useful tool for tool for improving service delivery, clinical governance, and the education and performance of the dental team. This study develops the discussion by investigating its use as an educational tool within UK Dental
[...] Read more.
Clinical Audit (CA) has been recognized as a useful tool for tool for improving service delivery, clinical governance, and the education and performance of the dental team. This study develops the discussion by investigating its use as an educational tool within UK Dental Foundation Training (DFT). The aim was to investigate the views of Foundation Dentists (FDs) and Training Programme Directors (TPDs) on the CA module in their FD training schemes, to provide insight and recommendations for those supervising and undertaking CA. A literature review was conducted followed by a qualitative research methodology, using group interviews. The interviews were transcribed and thematically analyzed using NVIVO, a Computer-Assisted Qualitative Data Analysis tool. CA was found to be a useful tool for teaching management and professionalism and can bring some improvement to clinical practice, but TPDs have doubts about the long-term effects on service delivery. The role of the Educational Supervisor (ES) is discussed and recommendations are given for those supervising and conducting CA. Full article
Figures

Figure 1

Open AccessCase Report
Meth Mouth—A Growing Epidemic in Dentistry?
Dent. J. 2017, 5(4), 29; doi:10.3390/dj5040029 -
Abstract
In the past two decades, the synthetic style and fashion drug “crystal meth” (“crystal”, “meth”), chemically representing the crystalline form of the methamphetamine hydrochloride, has become more and more popular in the United States, in Eastern Europe, and just recently in Central and
[...] Read more.
In the past two decades, the synthetic style and fashion drug “crystal meth” (“crystal”, “meth”), chemically representing the crystalline form of the methamphetamine hydrochloride, has become more and more popular in the United States, in Eastern Europe, and just recently in Central and Western Europe. “Meth” is cheap, easy to synthesize and to market, and has an extremely high potential for abuse and dependence. As a strong sympathomimetic, “meth” has the potency to switch off hunger, fatigue and, pain while simultaneously increasing physical and mental performance. The most relevant side effects are heart and circulatory complaints, severe psychotic attacks, personality changes, and progressive neurodegeneration. Another effect is “meth mouth”, defined as serious tooth and oral health damage after long-standing “meth” abuse; this condition may become increasingly relevant in dentistry and oral- and maxillofacial surgery. There might be an association between general methamphetamine abuse and the development of osteonecrosis, similar to the medication-related osteonecrosis of the jaws (MRONJ). Several case reports concerning “meth” patients after tooth extractions or oral surgery have presented clinical pictures similar to MRONJ. This overview summarizes the most relevant aspect concerning “crystal meth” abuse and “meth mouth”. Full article
Figures

Figure 1

Open AccessArticle
Nanoclay-Reinforced Glass-Ionomer Cements: In Vitro Wear Evaluation and Comparison by Two Wear-Test Methods
Dent. J. 2017, 5(4), 28; doi:10.3390/dj5040028 -
Abstract
Glass ionomer cement (GIC) represents a major transformation in restorative dentistry. Wear of dental restoratives is a common phenomenon and the determination of the wear resistance of direct-restorative materials is a challenging task. The aim of this paper was to evaluate the wear
[...] Read more.
Glass ionomer cement (GIC) represents a major transformation in restorative dentistry. Wear of dental restoratives is a common phenomenon and the determination of the wear resistance of direct-restorative materials is a challenging task. The aim of this paper was to evaluate the wear resistance of novel glass ionomer cement by two wear-test methods and to compare the two wear methods.The wear resistance of a conventional glass ionomer cement (HiFi Advanced Health Care Kent, UK) and cements modified by including various percentages of nanoclays (1, 2 and 4 wt %) was measured by a reciprocating wear test (ball-on-flat) and Oregon Health and Sciences University’s (OHSU) wear simulator. The OHSU wear simulation subjected the cement specimens to three wear mechanisms, namely abrasion, three-body abrasion and attrition using a steatite antagonist. The abrasion wear resulted in material loss from GIC specimen as the steatite antagonist forced through the exposed glass particles when it travelled along the sliding path.The hardness of specimens was measured by the Vickers hardness test. The results of reciprocation wear test showed that HiFi-1 resulted in the lowest wear volume 4.90 (0.60) mm3 (p < 0.05), but there was no significant difference (p > 0.05) in the wear volume in comparison to HiFi, HiFi-2 and HiFi-4. Similarly, the results of OHSU wear simulator showed that the total wear volume of HiFi-4 1.49 (0.24) was higher than HiFi-1 and HiFi-2. However, no significant difference (p > 0.05) was found in the OHSU total wear volume in GICs after nanoclay incorporation. The Vickers hardness (HV) of the nanoclay-reinforced cements was measured between 62 and 89 HV. Nanoclay addition at a higher concentration (4%) resulted in higher wear volume and wear depth. The total wear volumes were less dependent upon abrasion volume and attrition volume. The total wear depths were strongly influenced by attrition depth and to some extent by abrasion depth. The addition of nanoclay in higher wt % to HiFi did not result in significant improvement in wear resistance and hardness. Nonetheless, wear is a very complex phenomenon because it is sensitive to a wide number of factors that do not necessarily act in the same way when compared using different parameters. Full article
Figures

Figure 1

Open AccessArticle
Dentin Erosion: Method Validation and Efficacy of Fluoride Protection
Dent. J. 2017, 5(4), 27; doi:10.3390/dj5040027 -
Abstract
The aging population experiences more gingival recession and root exposure which increases the opportunity for dentin erosion. This study tested the use of transverse microradiography (TMR) methods to assess dentin erosion and the interaction between fluoride and citric acid on the amount of
[...] Read more.
The aging population experiences more gingival recession and root exposure which increases the opportunity for dentin erosion. This study tested the use of transverse microradiography (TMR) methods to assess dentin erosion and the interaction between fluoride and citric acid on the amount of erosion in the dentin samples. In a 4 × 3 interaction experimental design, four fluoride concentrations (0.00, 25.0, 50.0, and 100.0 mg/L) and three citric acid concentrations (0.0, 0.25, and 1.00%) were combined to form 12 experimental solutions. Forty-eight dentin samples were placed in the experimental solutions for 1 and 4 h and the amount of surface lost was determined by TMR methods. The resolution of the TMR method was 0.9 μm per pixel with a 0.1% and a 5% confidence interval of ±4.2 μm. Dentin erosion increased with the concentration of citric acid and time, the erosion decreased when concentration of fluoride was increased. Effects due to fluoride and citric acid concentrations individually, and their interaction on the amount of erosion observed was statistically significant (p < 0.0001). This study found that TMR methods are appropriate and that 25.0 mg/L was the optimal fluoride concentration to protect dentin from a 1.00% citric acid challenge. Full article
Figures

Figure 1