Risk aspects of dental restoratives: From amalgam to tooth-colored materials

Dental materials’ choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today tooth-colored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material (amalgam) with an equal material (resin composite) being more esthetic but also biologically questionable For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of non-biocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.

Effects of low intensity laser irradiation phototherapy on dental pulp constructs

AIM: To investigate low intensity laser irradiation phototherapy (LILIP) on the proliferation, mineralization and degradation of dental pulp constructs.

METHODS: Stem cells from human exfoliated deciduous teeth (SHED) were grown to confluence and seeded on collagen scaffolds to create dental pulp constructs. LILIP was delivered to the dental pulp constructs using an 830 nm GaAIAs laser at an output power of 20 mW. The LILIP energy density was 0.4, 0.8, 1.2, and 2.4 J/cm². After 8 d, the cell proliferation and degradation within the dental pulp constructs were measured using histologic criteria. After 28 d, the effect of LILIP on SHED mineralization was assessed by von Kossa staining.

RESULTS: SHED proliferation within the dental pulp constructs varied after exposure to the 0.4, 0.8, 1.2, and 2.4 J/cm² LILIP energy densities (P < 0.05). The maximum proliferation of SHED in nutrient deficient media was 218% after exposure to a 1.2 J/cm² LILIP energy density. SHED grown in nutrient deficient media after exposure to a 0.4, 0.8, and 1.2 J/cm² LILIP energy density, proliferated by 167-218% compared to the untreated (non-LILIP) control group (P < 0.05). SHED exposed to a 0.4, 0.8, and 1.2 J/cm² LILIP energy density, and grown in optimal nutritional conditions and proliferated by 147%-164% compared to the untreated (non-LILIP) control group (P < 0.05). The exposure of SHED to the highest LILIP energy density (2.4 J/cm²) caused a reduction of the cell proliferation of up to 73% of the untreated (non-LILIP) control (P < 0.05). The amount of mineral produced by SHED increased over time up to 28 d (P < 0.05). The 0.8 and 1.2 J/cm² LILIP energy densities were the most effective at stimulating the increased the mineralization of the SHED from 150%-700% compared to untreated (non-LILIP) control over 28 d (P < 0.05). The degradation of dental pulp constructs was affected by LILIP (P < 0.05). The dental pulp constructs grown in optimal nutritional conditions exposed to a 0.8 J/cm² or 1.2 J/cm² LILIP energy density had 13% to 16% more degradation than the untreated (non-LILIP) control groups (P < 0.05). The other LILIP energy densities caused a 1% degradation of dental pulp constructs in optimal nutritional conditions (P > 0.05).

CONCLUSION: LILIP can enhance or reduce SHED proliferation, degradation and mineralization within dental pulp constructs. LILIP could promote the healing and regeneration of dental tissues.

Ozone action on Streptococcus mutans and Lactobacillus fermentum: A pilot study

AIM: To study the effectiveness of ozone in the elimination of cariogenic bacteria, followed with fluoride supplements.

METHODS: Sixty extracted teeth free of caries were used, and five groups were constituted. In Group I, the teeth were immersed in artificial saliva. In Group II, the teeth were inoculated with Streptococcus mutans (S. mutans) and immersed in artificial saliva. In Group III the teeth were inoculated with Lactobaccilus fermentum (L. fermentum) and immersed in artificial saliva. In Group IV the teeth were inoculated with S. mutans and L. fermentum and immersed in artificial saliva and the teeth in Group V were inoculated with S. mutans and L. fermentum, and were subjected to the application of ozone and to the action of a fluoride mineralizing gel. DIAGNOdent was used to evaluate the caries of the teeth 3 wk after inoculation of bacteria and after that the teeth of Group V were subjected to the application of ozone during 60 s, by HealOzone. After the application of ozone, products of the remineralization kit supplied by the manufacturer were applied daily, during 30 d. At the end samples were collected for analysis and evaluation of bacterial activity by polymerase chain reaction.

RESULTS: Regarding the value of caries, obtained via DIAGNOdent, in the initial measurement the groups are homogeneous (P = 0.730). There was an increase in DIAGNOdent values, presenting statistical significant difference regarding the initial measurement in all groups (P ˂ 0.001), except in group I - only artificial saliva - which shows that the artificial carie model was effective. Comparing the initial and final measurements for each of the 60 teeth, it can be observed that in 9 teeth (15.0%) there was a decrease in values between the two measurements, one (1.7%) retained the same values in the two measurements and in the remaining 50 cases (83.3%) there was increase in values between the initial and final measurements. It should also be noted that in the teeth inoculated with S. mutans + L. fermentum, there was an increase of the values in 100% of cases, and in all groups except the group with artificial saliva, there is a more frequent increase in the values. In group V, subject to the application of ozone, bacterial DNA was not detected, in group IV, bacterial DNA was detected.

CONCLUSION: Ozone was effective in the elimination of the study bacteria.

MMP-8 analysis in gingival crevicular fluid using ELISA and novel chair-side test

AIM: To validate accuracy of a novel chair-side test for matrix metalloproteinase (MMP)-8 as compared to enzyme-linked immunosorbent assay (ELISA) in Periodontal health and disease.

METHODS: Gingival crevicular fluid was collected from 150 subjects, Group 1 (healthy) - 50 subjects, Group 2 (gingivitis) - 50 subjects and Group 3 (chronic periodontitis) - 50 subjects. A chair-side test strip was indigenously prepared using polyclonal antibodies (principle of immunochromatography) to detect the MMP-8 levels. The detection accuracy (sensitivity and specificity) of the MMP-8 levels by chair-side test kit were compared with ELISA at baseline and 3 mo after scaling and root planing among the study population.

RESULTS: The novel chair side test detected MMP-8 levels in accordance with ELISA which at baseline were higher in Group 2 and Group 3 as compared to controls (P < 0.05), and these enzyme levels decreased after therapy (P < 0.05). The chair-side test could differentiate healthy, gingivitis and periodontitis. The detection accuracy of the chair-side test strip were on par with ELISA (sensitivity 92.9% and specificity of 100%) which were statistically significant (P < 0.05). A desire to arouse interest about periodontal health and maintenance in the Indian population provided a strong rationale for us to develop our chair-side test strips to suit our economy. Moreover, this was the first ever effort to develop and validate a chair-side test strip to detect MMP-8 levels in the Indian population. This test can be used on a large scale in private dental practice for the early detection of disease, tapping the sites at risk for disease, alongside helps in patient education and motivation for maintenance.

CONCLUSION: This study shows that the novel chair side test kit detects MMP-8 levels a biomarker of periodontal disease progression accurately making it a good chair side diagnostic tool. Further, it is cost effective and time saving which can make it applicable in private dental practice on a large scale for the early detection of periodontal disease.

What is the purpose of launching the World Journal of Stomatology?

Congratulations to the publisher, members of the editorial board of the journal, all the authors and readers for launching the World Journal of Stomatology (WJS) as a new member of the World series journal family! Significant scientific advances and important breakthroughs need to be published to impact dental care and reach an audience of researchers and clinicians who can create more effective dental treatments for their patients. There is a need to share scientific information, methodologies, therapies, and hypotheses related to stomatology, through an open-access format, to reach the widest possible audience. The WJS was created to fulfill the role of disseminating the most significant, innovative and transformational cutting edge research in dentistry. The WJS is a peer-reviewed open-access periodical centered in stomatology, with a multidisciplinary coverage that will publish high-impact articles in all areas of the dental clinical specialties, applied science, epidemiology, trauma and dental care, dental materials, oral biology and microbiology. The WJS is not scared of controversy or challenges to existing doctrine, since they are supported by high-quality science or unequivocal clinical outcomes. The WJS will avoid publishing confirmatory and low-impact articles. The WJS will only publish articles directly relevant to stomatology and dentistry because this is what our readers expect. If you need to share any exciting dental research discoveries and reach the widest possible audience, you will find in the WJS the most helpful resource to publish your papers!