Enamel microabrasion: An overview of clinical and scientific considerations

Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a lowrotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.

Posterior partially edentulous jaws, planning a rehabilitation with dental implants

AIM: To discuss important characteristics of the useof dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE(PubM ed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review. RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations(bone quantity and density), radiographic techniques, implant selection(number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters. CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning.

Biomechanical Analysis of Implant Assisted-Overdentures with Variations in the Attachments Systems

The aim of this study was to assess the stress patterns on the peri-implant zone and residual alveolar ridge in different overdenture attachment system designs by the photoelasticity method. Four attachments systems were tested: O-ring, ERA, Bar-clip, and Bar-clip/O-ring association. The prostheses were loaded with 100 N in five pre-determined points and the photoelastic model was evaluated by a circular polariscope. The anterior load, O-ring, and ERA showed better stress distribution in relation to the bars systems, which presented stress levels surrounding implants. The molar load, Bar-clip/O-ring association, presented the biggest stress concentration on the peri-implant region in relation to the others. When the second molar was loaded, there was a concentration of stress in the alveolar ridge in all situations analyzed. Within the limitation of this “in vitro” study, it could be concluded that there were biomechanical differences among the attachments systems analyzed, principally between isolated and the bars systems. The O-ring showed better stress distribution and the Bar-clip/O-ring showed higher stress concentration.

Understanding of Socially Vulnerable Individuals on Oral Health and Access to Dentist: A Brazilian Study

Social vulnerability experienced by collectors of recyclable materials has a strong influence on their understanding and confrontations health. This research aimed to explore the relationship between oral health and perception of subjects in a context of social disadvantage, in order to support concrete alternatives for action on (oral) health conference. This was a qualitative study carried out with representatives of an autonomous community of Brazilian collectors of recyclable materials. Data were collected through interviews and focus group treated with the technique of qualitative analysis. Respondents showed perceptions of etiology and care practices on oral health promoted beliefs and values collectively instituted in a social risk territory. Also, they associate the quality of their oral health and their difficulty of public access to the context of social vulnerability. This study suggests the adoption of protective, educational and interceptive in oral health practice in order to improve and enable the oral health status of this population.

Fine mapping of genomic regions associated with female fertility in Nellore beef cattle based on sequence variants from segregating sires

Background:Impaired fertility in cattle limits the efficiency of livestock production systems.Unraveling the genetic architecture of fertility traits would facilitate their improvement by selection.In this study,we characterized SNP chip haplotypes at QTL blocks then used whole-genome sequencing to fine map genomic regions associated with reproduction in a population of Nellore(Bos indicus)heifers.Methods:The dataset comprised of 1337 heifers genotyped using a GeneSeek®Genomic Profiler panel(74677 SNPs),representing the daughters from 78 sires.After performing marker quality control,64800 SNPs were retained.Haplotypes carried by each sire at six previously identified QTL on BTAs 5,14 and 18 for heifer pregnancy and BTAs 8,11 and 22 for antral follicle count were constructed using findhap software.The significance of the contrasts between the effects of every two paternally-inherited haplotype alleles were used to identify sires that were heterozygous at each QTL.Whole-genome sequencing data localized to the haplotypes from six sires and 20 other ancestors were used to identify sequence variants that were concordant with the haplotype contrasts.Enrichment analyses were applied to these variants using KEGG and MeSH libraries.Results:A total of six(BTA 5),six(BTA 14)and five(BTA 18)sires were heterozygous for heifer pregnancy QTL whereas six(BTA 8),fourteen(BTA 11),and five(BTA 22)sires were heterozygous for number of antral follicles’QTL.Due to inadequate representation of many haplotype alleles in the sequenced animals,fine mapping analysis could only be reliably performed for the QTL on BTA 5 and 14,which had 641 and 3733 concordant candidate sequence variants,respectively.The KEGG“Circadian rhythm”and“Neurotrophin signaling pathway”were significantly associated with the genes in the QTL on BTA 5 whereas 32 MeSH terms were associated with the QTL on BTA 14.Among the concordant sequence variants,0.2%and 0.3%were classified as missense variants for BTAs 5 and 14,respectively,highlighting the genes MTERF2,RTMB,ENSBTAG00000037306(miRNA),ENSBTAG00000040351,PRKDC,and RGS20.The potential causal mutations found in the present study were associated with biological processes such as oocyte maturation,embryo development,placenta development and response to reproductive hormones.Conclusions:The identification of heterozygous sires by positionally phasing SNP chip data and contrasting haplotype effects for previously detected QTL can be used for fine mapping to identify potential causal mutations and candidate genes.Genomic variants on genes MTERF2,RTBC,miRNA ENSBTAG00000037306,ENSBTAG00000040351,PRKDC,and RGS20,which are known to have influence on reproductive biological processes,were detected.

Protective Properties in Hymenaea martiana Hayne against Multi-drug-resistant Staphylococcus aureus

Antibiotic resistance represents a widespread problem in milk production.The identification of compounds for a topically applied ointment used in mastitis therapy remains elusive.Compounds from the genus Hymenaea can be administered in cases of multi-drugresistant Staphylococcus aureus infection for ruminant species,but the protective properties are not well known.Wi this research the aim is verify the protective effects of H.martiana against S.aureus infection in bovine mammary epithelial cell line(MAC-T)and to obtain an antioxidant profile evaluation in vitro.The MAC-T cells were challenged with S.aureus after being exposed to the extract of the H.martiana in the protective assay.For the verification of the viability of the MAC-T cells,the MTT assay was performed,and was used dilutions of the plant extract,starting at 2.5%.The extract of H.martiana was evaluated for antioxidant aspect in different dilutions by FRAP,ORAC and DPPH.A variety of flavonoids(quercetin,luteolin,etc.)have been identified as the main components by using mass spectrometry,reinforcing our in vitro findings that flavonoids,especially quercetin,have a medicinal profile capable of killing mastitis-causing bacteria.An excellent antioxidant pattern was observed in the 2.5%solution;however,membrane integrity in MAC-T cells was compromised.Those findings suggest low dilutions of H.martiana extract has a desirable protective effect from S.aureus pathogenesis.Our in vitro studies can be gleaned upon for further in vivo studies.

Collagen membrane functionalized with magnesium oxide via room-temperature atomic layer deposition promotes osteopromotive and antimicrobial properties

Artificial bone grafting materials such as collagen are gaining interest due to the ease of production and implantation.However,collagen must be supplemented with additional coating materials for improved osteointegration.Here,we report room-temperature atomic layer deposition(ALD)of MgO,a novel method to coat collagen membranes with MgO.Characterization techniques such as X-ray photoelectron spectroscopy,Raman spectroscopy,and electron beam dispersion mapping confirm the chemical nature of the film.Scanning electron and atomic force microscopies show the surface topography and morphology of the collagen fibers were not altered during the ALD of MgO.Slow release of magnesium ions promotes bone growth,and we show the deposited MgO film leaches trace amounts of Mg when incubated in phosphate-buffered saline at 37◦C.The coated collagen membrane had a superhydrophilic surface immediately after the deposition of MgO.The film was not toxic to human cells and demonstrated antibacterial properties against bacterial biofilms.Furthermore,in vivo studies performed on calvaria rats showed MgO-coated membranes(200 and 500 ALD)elicit a higher inflammatory response,leading to an increase in angiogenesis and a greater bone formation,mainly for Col-MgO500,compared to uncoated collagen.Based on the characterization of the MgO film and in vitro and in vivo data,the MgO-coated collagen membranes are excellent candidates for guided bone regeneration.