Relationship between oral microbiota and colorectal cancer: A systematic review.

This systematic review aims to investigate the microbial basis underlying the association between oral microbiota and colorectal cancer. A comprehensive search was conducted across four databases, encompassing potentially relevant studies published up to April 2024 related to the PECO question: "Is there a differentiation in oral microbial composition between adult patients diagnosed with colorectal cancer compared to healthy patients?". The Newcastle-Ottawa Scale was used to evaluate the quality of the studies included. The level of evidence was assessed through the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) tool. Sixteen studies fulfilled the eligibility criteria. Based on low to moderate evidence profile, high levels of certain subspecies within Firmicutes (such as Streptococcus anginosus, Peptostreptococcus stomatis, S. koreensis, and S. gallolyticus), Prevotella intermedia, Fusobacterium nucleatum, and Neisseria oralis were found to be associated with colorectal cancer. Conversely, certain bacteria (e.g., Lachnospiraceae, F. periodonticum, and P. melaninogenica) could exert a symbiotic protective effect against colorectal cancer. Based on existing evidence, it appears that variations in oral microbiota composition exist among individuals with and without colorectal cancer. However, further research is necessary to determine the mechanisms of oral dysbiosis in colorectal carcinogenesis.

Full-length 16S rRNA gene sequencing by PacBio improves taxonomic resolution in human microbiome samples.

BACKGROUND: Sequencing variable regions of the 16S rRNA gene (≃300 bp) with Illumina technology is commonly used to study the composition of human microbiota. Unfortunately, short reads are unable to differentiate between highly similar species. Considering that species from the same genus can be associated with health or disease it is important to identify them at the lowest possible taxonomic rank. Third-generation sequencing platforms such as PacBio SMRT, increase read lengths allowing to sequence the whole gene with the maximum taxonomic resolution. Despite its potential, full length 16S rRNA gene sequencing is not widely used yet. The aim of the current study was to compare the sequencing output and taxonomic annotation performance of the two approaches (Illumina short read sequencing and PacBio long read sequencing of 16S rRNA gene) in different human microbiome samples. DNA from saliva, oral biofilms (subgingival plaque) and faeces of 9 volunteers was isolated. Regions V3-V4 and V1-V9 were amplified and sequenced by Illumina Miseq and by PacBio Sequel II sequencers, respectively. RESULTS: With both platforms, a similar percentage of reads was assigned to the genus level (94.79% and 95.06% respectively) but with PacBio a higher proportion of reads were further assigned to the species level (55.23% vs 74.14%). Regarding overall bacterial composition, samples clustered by niche and not by sequencing platform. In addition, all genera with > 0.1% abundance were detected in both platforms for all types of samples. Although some genera such as Streptococcus tended to be observed at higher frequency in PacBio than in Illumina (20.14% vs 14.12% in saliva, 10.63% vs 6.59% in subgingival plaque biofilm samples) none of the differences were statistically significant when correcting for multiple testing. CONCLUSIONS: The results presented in the current manuscript suggest that samples sequenced using Illumina and PacBio are mostly comparable. Considering that PacBio reads were assigned at the species level with higher accuracy than Illumina, our data support the use of PacBio technology for future microbiome studies, although a higher cost is currently required to obtain an equivalent number of reads per sample.

Bibliometric study of the systematic reviews and meta-analyses in dentistry.

Background: Scientific production has increased in the last decades, consequently the number of systematic reviews, reviews and meta-analyses, the objective is to carry out a bibliometric analysis study of systematic reviews and meta-analyses in dentistry, divided into different thematic areas. Material and Methods: A search was conducted in the Science Citation Index-Expanded on the core collection of Web of Science, they were selected from the area of Dentistry and Oral Surgery and Medicine categories, the data was downloaded on April 20, 2022 and The 100 most cited articles from each of the thematic areas were selected. Results: An increase in this type of articles was observed in the last decade in the areas of pediatric and medical dentistry and oral pathology. The thematic area that received the most citations was periodontics. The two authors with the most citations are Zwahlen, Marcel and Pjetursson, Bjarni Eluar. The countries that receive the most citations are European, along with the USA and China. The topics that are most published in this type of article deal with Cancer with 50 publications, caries treatment with 25 and fluoridation with 1. The entities that finance this type of articles the most are private companies (26.76%). Conclusions: Together with an exponential increase in the number of publications in dentistry, there has been an increase in the number of publications in systematic reviews. The areas publishing the most articles and having the most citations are Periodontics and Implantology, despite the fact that the most studied topic is cancer. Key words:Bibliometrics, methodological study, systematics reviews, metanalys.

MicroRNAs in Gingival Crevicular Fluid: An Observational Case-Control Study of Differential Expression in Periodontitis.

OBJECTIVES: microRNAs (miRNAs) present in the gingival crevicular fluid (GCF) of patients with chronic periodontitis may serve as biomarkers of periodontal disease. The aim of this study was to perform a miRNA-sequencing study of all miRNAs present in GCF, comparing miRNA expression level profiles between advanced chronic periodontitis (CP) patients and healthy subjects (HS). MATERIALS AND METHODS: GCF samples were collected from the single-rooted teeth of patients with severe CP (n = 11) and of HS (n = 12). miRNAs were isolated from GCF using an miRNeasy Serum/Plasma kit(Qiagen GmbH, Hilden, Germany). Reverse transcription polymerase chain reaction (qRT-PCR) was used to determine the expression levels of miRNA candidates involved in periodontal pathogenesis. RESULTS: Of all the sequenced miRNAs, miR-199, miR-146a, miR-30a, and miR-338 were identified as best representing the CP patient samples. The validation study identified miR-199 as the most powerful biomarker used to define periodontitis. CONCLUSIONS: Upon sequencing all known miRNAs in GCF for the first time, we uncovered several potential biomarkers to define periodontitis. Identifying miRNAS in the GCF using high-throughput approaches will clarify the role of these molecules in periodontitis and provide biomarkers with potential applications.

Personalized antibiotic selection in periodontal treatment improves clinical and microbiological outputs.

Introduction: Periodontitis is a biofilm-mediated disease that is usually treated by non-surgical biofilm elimination with or without antibiotics. Antibiotic treatment in periodontal patients is typically selected empirically or using qPCR or DNA hybridization methods. These approaches are directed towards establishing the levels of different periodontal pathogens in periodontal pockets to infer the antibiotic treatment. However, current methods are costly and do not consider the antibiotic susceptibility of the whole subgingival biofilm. Methods: In the current manuscript, we have developed a method to culture subgingival samples ex vivo in a fast, label-free impedance-based system where biofilm growth is monitored in real-time under exposure to different antibiotics, producing results in 4 hours. To test its efficacy, we performed a double-blind, randomized clinical trial where patients were treated with an antibiotic either selected by the hybridization method (n=32) or by the one with the best effect in the ex vivo growth system (n=32). Results: Antibiotic selection was different in over 80% of the cases. Clinical parameters such as periodontal pocket depth, attachment level, and bleeding upon probing improved in both groups. However, dental plaque was significantly reduced only in the group where antibiotics were selected according to the ex vivo growth. In addition, 16S rRNA sequencing showed a larger reduction in periodontal pathogens and a larger increase in health-associated bacteria in the ex vivo growth group. Discussion: The results of clinical and microbiological parameters, together with the reduced cost and low analysis time, support the use of the impedance system for improved individualized antibiotic selection.

The 100 most cited articles in peri-implant diseases. A bibliometric study of the web of science.

Background: The purpose of the study was to analyze the 100 most-cited articles on peri-implantitis pathology in the Web of Science database. Material and Methods: The articles were selected from all categories of the Web of Science, to consider all variations and synonyms of peri-implant disease. Articles were reviewed for typographical, transcription, and indexing errors. Results: The top 100 most-cited articles were published from 1994 to 2018, and had a total of 24,103 citations; 53 of the studies were funded. In total, 274 authors contributed to the papers, 5 of whom contributed to 10 or more articles. Review (n = 47) and clinical (n = 45) articles were the most prevalent types. European public universities made the largest contribution to the literature, and Sweden and Switzerland were the most active countries. All of the articles were published in 12 high-impact-factor journals. Conclusions: This is the first analysis of the most-cited articles on periimplantitis published in the Web of Science. In this bibliometric analysis, the most cited articles were published in high-impact-factor journals and were predominantly review articles. The most-cited authors are also active in other scientific disciplines such as periodontics. Key words:Dental implantation, Dental implants, Peri-implantitis, Mucositis.

MicroRNAs and periodontal disease: a qualitative systematic review of human studies.

PURPOSE: MicroRNAs (miRNAs) are epigenetic post-transcriptional regulators that modulate gene expression and have been identified as biomarkers for several diseases, including cancer. This study aimed to systematically review the relationship between miRNAs and periodontal disease in humans, and to evaluate the potential of miRNAs as diagnostic and prognostic biomarkers of disease. METHODS: The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (reference number CRD42020180683). The MEDLINE, Scopus, Cochrane Library, Embase, Web of Science, and SciELO databases were searched for clinical studies conducted in humans investigating periodontal diseases and miRNAs. Expression levels of miRNAs across the different groups were analysed using the collected data. RESULTS: A total of 1,299 references were identified in the initial literature search, and 23 articles were finally included in the review. The study designs were heterogeneous, which prevented a meta-analysis of the data. Most of the studies compared miRNA expression levels between patients with periodontitis and healthy controls. The most widely researched miRNA in periodontal diseases was miR-146a. Most studies reported higher expression levels of miR-146a in patients with periodontitis than in healthy controls. In addition, many studies also focused on identifying target genes of the differentially expressed miRNAs that were significantly related to periodontal inflammation. CONCLUSIONS: The results of the studies that we analysed are promising, but diagnostic tests are needed to confirm the use of miRNAs as biomarkers to monitor and aid in the early diagnosis of periodontitis in clinical practice.

Bibliometric analysis of the scientific production of literature on peri-implant diseases in the Web of Science.

BACKGROUND: The exponential increase in implant placement worldwide and the high prevalence of its associated pathologies have prompted an increasing contribution by the scientific community to the number of publications related to peri-implant pathologies. PURPOSE: The objective of this work is to carry out a bibliometric analysis of scientific production on peri-implant diseases. MATERIALS AND METHODS: The search strategy included titles, keywords, and abstracts based on the term peri-implantitis and all the possible combinations existing in Science Citation Index Expanded (SCIE) of the main collection of Web of Science. Two limits were established: the document typology was limited to Article and Review, and articles published up to 2019 were selected. All articles were refined and standardized manually to avoid typographical errors and duplications in authors' names or institutions. RESULTS: The total number of papers collected was 2547. A significant increase was observed in the number of articles published, especially in the past 10 years. The three most productive authors were Europeans, and the 45 most productive institutions were the universities. The most productive funding entities were the governments. Of the published works, 42.28% were funded. Of the 2547 records, 86.53% presented keywords. CONCLUSIONS: Scientific literature on peri-implantitis shows scientific growth in recent years, with a growing trend towards collaboration between authors and institutions. Most of the works have been published in high-impact journals, and in the last 2 years, more than half of the works have received some type of public or private funding.

Performance of the dentogingival junction with mta and biodentine on the treatment of invasive cervical resorptions. A literature review and case report.

Invasive cervical resorption (ICR) is an uncommon phenomenon (0.1%), however, it represents a challenge to the structural and functional integrity of the dentogingival junction, as well as a risk for the survival of the affected tooth. They are characterized by their location and invasive character, being able to appear in any tooth of the permanent dentition. It shows up after the damage to the cervical insertion apparatus, leaving the pulp without participation in the origin of the lesion. They may appear just below the junctional epithelium or at a more apical level. The MTA® (Dentsply, Tulsa dental, Tulsa OK) and the Biodentine® (Septodent, Saint Maur of Fossés, France) are two biomaterials that have demonstrated the ability to promote the neoformation of cement so they are considered an alternative in the treatment of the ICR. This article presents an ICR clinical cases treated with these biomaterials, in which favorable post-operative healing is observed. Key words:MTA, Biodentine, biomaterials, root resorption, invasive cervical resorption.

Impact of periodontal treatment on the RANKL/OPG ratio in crevicular fluid.

AIM: Alveolar resorption is one of the most important events in periodontitis. Osteoclast activity is regulated by the ratio between receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). The aim of this study was to evaluate changes in the RANKL/OPG ratio in crevicular fluid after periodontal treatment. MATERIAL AND METHODS: A total of 15 patients with periodontitis were included in the study group. Samples were collected from an area with active periodontitis and a healthy area. The RANKL and OPG levels were measured before and after periodontal scaling and root planing (SRP) treatment. The study group was compared to the control group, which included 10 patients without periodontitis. ID Clinicaltrial.gov: NCT03787875. RESULTS: A decrease in the RANKL level was found in areas with active periodontitis after periodontal treatment, but no change in the OPG level was observed. Therefore, the treatment induced a decrease in the RANKL/OPG ratio in sites with destructive periodontal activity. CONCLUSIONS: Periodontal treatment acts on the RANKL/OPG ratio by decreasing osteoclastogenesis. These results encourage the use of these molecules for periodontal diagnosis, monitoring and treatment. ID CLINICALTRIAL.GOV: NCT03787875.

Epigenetics and periodontics: A systematic review

Background: Despite decades of research, our knowledge of several important aspects of periodontal pathogenesis remains incomplete. Epigenetics allows to perform dynamic analysis of different variations in gene expression, providing this great advantage to the static measurement provided by genetic markers. The aim of this systematic review is to analyze the possible relationships between different epigenetic mechanisms and periodontal diseases, and to assess their potential use as biomarkers of periodontitis. Material and Methods: A systematic search was conducted in six databases using MeSH and non-MeSH terms. The review fulfilled PRISMA criteria (Preferred Reporting Items for Systematic reviews and Meta-analysis). Results: 36 studies met the inclusion criteria. Due to the heterogeneity of the articles, it was not possible to conduct quantitative analysis. Regarding qualitative synthesis, however, it was found that epigenetic mechanisms may be used as biological markers of periodontal disease, as their dynamism and molecular stability makes them a valu-able diagnostic tool. Conclusions: Epigenetic markers alter gene expression, producing either silencing or over-expression of molecular transcription that respond to the demands of the cellular surroundings. Gingival crevicular fluid collection is a non-invasive and simple procedure, which makes it an ideal diagnostic medium for detection of both oral and systemic issues. Although further research is needed, this seems to be a promising field of research in the years to come

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miR-1226 detection in GCF as potential biomarker of chronic periodontitis: A pilot study

BACKGROUND: The study and identification of new biomarkers for periodontal disease, such as microRNAs (miR-NAs), may give us more information about the location and severity of the disease and will serve as a basis for treatment planning and disease-monitoring. miRNAs are a group of small RNAs which are involved in gene regulation by binding to their messenger RNA target (mRNA). In this pilot study, the procedure for purifying miRNAs from gingival crevicular fluid (GCF) was, for the first time, described. In addition, the concentration of miRNAs in GCF was analyzed and compared between patients with moderate or severe chronic periodontitis (CP) and healthy controls. MATERIAL AND METHODS: GCF samples were collected from single-rooted teeth of patients with moderate or severe CP (n=9) and of healthy individuals (n=9). miRNAs were isolated from GCF using miRNeasy Serum/Plasma kit (Qiagen, CA. USA). Reverse transcription polymerase chain reaction (qRT-PCR) was used to determine the expression of a series of miRNAs candidates that are related to bone metabolism. The significance of differences in miRNA levels between both groups was determined using Mann-Whitney U test. RESULTS: The results from this pilot study indicate that miRNAs can be isolated from GCF. Six different miRNAs were analyzed (miR-671, miR-122, miR-1306, miR-27a, miR-223, miR-1226), but only miR-1226 showed statically significant differences between the CP group and healthy controls (p < 0.05). This miRNA was downregulated in patients with CP. CONCLUSIONS: Within the limitations of the present study, it may be concluded that miR-1226 can be a promising biomarker for periodontal disease, adding relevant information to common clinical parameters used for diagnosis and prognosis of periodontitis

Effects of photodynamic therapy in periodontal treatment: A randomized, controlled clinical trial.

AIM: To evaluate the effects of photodynamic therapy (PDT) in the nonsurgical treatment of chronic periodontitis. MATERIALS AND METHODS: A randomized, single-blind, controlled, parallel-group clinical trial was performed. Sixty patients were enrolled: 20 healthy controls and 40 patients with periodontitis. The 40 patients were randomized for scaling and root planing (SRP) or SRP + PDT. Periodontal (plaque index, probing depth, clinical recession, clinical attachment level, bleeding on probing and gingival crevicular fluid volume, corresponding to 381 versus 428 critical sites), microbiological (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia and Campylobacter rectus presence, 18 versus 19 samples) and biochemical (interleukin (IL)-1ß, IL-6 and tumour necrosis factor (TNF)-α, receptor activator of nuclear factor-kappaB ligand (RANK-L) and osteoprotegerin (OPG) levels, 18 versus 19 samples) parameters were recorded. RESULTS: Within each group, significant improvements were found for clinical parameters, though without significant differences between groups. RANK-L was significantly decreased at week 13 in the SRP + PDT group compared with the SRP group. SRP + PDT, but not SRP alone, significantly reduced the abundance of A. actinomycetemcomitans. CONCLUSIONS: Except for a significant decrease in the pathogenic burden of A. actinomycetemcomitans, coadjuvant PDT resulted in no additional improvement compared with SRP alone in patients diagnosed with moderate-to-advanced chronic periodontitis.

A controlled clinical study of periodontal health in anticoagulated patients: Assessment of bleeding on probing.

BACKGROUND: According to the Spanish Society of Cardiology, 700,000 patients receive oral anticoagulants, and in these cases bleeding on probing (BOP) could be altered. However, no studies have analyzed the periodontal status of these patients and the effects anticoagulants may have upon BOP. A study was made of the possible relationship between plaque index, probing depth, INR (International Normalized Ratio) and acenocoumarol dose versus the clinical signs of BOP in a sample of anticoagulated patients. Likewise, an analysis was made of oral hygiene habits and attitude towards bleeding in these patients. MATERIAL AND METHODS: A controlled observational clinical study was made in La Ribera Hospital (Valencia, Spain) involving 44 anticoagulated patients treated with Sintrom® (acenocoumarol) and a homogeneous control group of 44 non-anticoagulated patients. A survey on oral hygiene habits and attitude towards bleeding was carried out, and the main periodontal parameters were recorded. RESULTS: Probing depth was the parameter with the strongest correlation to BOP (p<0.001), followed by the plaque index (p<0.002). In contrast, no relationship was observed between acenocoumarol dose or INR and BOP. Mean BOP was greater in the control group than in the anticoagulated group (p<0.001). Oral hygiene habits and attitude towards bleeding differed significantly between groups. CONCLUSIONS: We have found no explanation why BOP was greater in the control group. What seems clear is that in the presence of the same plaque index and probing depth, anticoagulated patients did not bleed more than non-anticoagulated patients. A lack of knowledge of health and oral hygiene habits was observed in these subjects. Key words:Anticoagulant therapy, bleeding on probing, periodontal health.

Comparison of the clinical effects of white brand toothbrushes versus Vitis Suave®.

BACKGROUND: There has been an increase in the use of white label manual toothbrushes and a greater increase in inquiries for discomfort of the gingiva and mucosa. MATERIAL AND METHODS: A randomized, double-blind, cross-over clinical trial was made of four white brand toothbrushes versus a control brush (Vitis Suave®), with the recording of plaque index, bleeding upon probing, and gingival abrasions following utilization of the different brushes. RESULTS: All the brushes except Deliplus® were equally effective in terms of plaque removal (p<0.05). Vitis Suave® and Veckia® were the brushes associated to the greatest increase in minor abrasions (p<0.01), while Veckia®, Carrefour® and Deluxe® significantly increased the number of medium intensity abrasions (p<0.05). These brushes also increased the number of large abrasions, though statistical significance was not reached in this case. CONCLUSIONS: The white brand brushes proved effective in controlling bacterial plaque, but were associated to more intense soft tissue abrasion. KEY WORDS: Gingival abrasions, manual tooth brushing, white brand, clinical effects.

Bone resorption processes in patients wearing overdentures. A 6-years retrospective study.

OBJECTIVES: 1. - To measure the alveolar resorption processes that occur in patients wearing mandibular overdentures on 2 implants and fully-removable maxillary dentures, and to evaluate the same process on patients wearing fully-removable dentures on both arches. 2.- To verify whether Kelly's Combination Syndrome occurs in the group of patients wearing overdentures. METHOD AND MATERIAL: Forty patients were evaluated, of which a "cases" group was formed by 25 patients wearing mandibular overdentures on 2 lower jaw implants and fully-removable dentures on the opposite arch. The other 15 patients formed a control group that wore fully-removable dentures on both arches. Each one of the patients underwent orthopantograms from the moment the dentures were inserted until an average of 6 years later, which were assessed based on the Xie et al. method to estimate vertical bone loss. Once the data was collected, it was subjected to statistical analysis. RESULTS: In terms of the maxillary midline, we observed a greater loss in patients wearing overdentures, which was statistically significant, as it registered 0.32 mm/year. Mandibular bone loss was 2.5 times less in patients in the cases group. The rest of the clinical criteria for Kelly's Combination Syndrome were not observed. CONCLUSIONS: Kelly's Combination Syndrome did not occur in the patients in the cases group. In spite of the greater bone loss on a premaxillary level in this group, the placing of the overdenture on the implants significantly reduced mandibular bone resorption.

Bone resorption processes in patients wearing overdentures. A 6-years retrospective study

Objectives: 1. – To measure the alveolar resorption processes that occur in patients wearing mandibular overdentures on 2 implants and fully-removable maxillary dentures, and to evaluate the same process on patients wearing fully- removable dentures on both arches. 2.- To verify whether Kelly’s Combination Syndrome occurs in the group of patients wearing overdentures. Method and Material: Forty patients were evaluated, of which a “cases” group was formed by 25 patients wearing mandibular overdentures on 2 lower jaw implants and fully-removable dentures on the opposite arch. The other 15 patients formed a control group that wore fully-removable dentures on both arches. Each one of the patients underwent orthopantograms from the moment the dentures were inserted until an average of 6 years later, which were assessed based on the Xie et al. method to estimate vertical bone loss. Once the data was collected, it was subjected to statistical analysis. Results: In terms of the maxillary midline, we observed a greater loss in patients wearing overdentures, which was statistically significant, as it registered 0.32 mm/year. Mandibular bone loss was 2.5 times less in patients in the cases group. The rest of the clinical criteria for Kelly’s Combination Syndrome were not observed.
Conclusions: Kelly’s Combination Syndrome did not occur in the patients in the cases group. In spite of the greater bone loss on a premaxillary level in this group, the placing of the overdenture on the implants significantly reduced mandibular bone resorption (AU)