Periodontal regeneration using platelet-rich fibrin. Furcation defects: A systematic review with meta-analysis.

The objective of the study was to compare the treatment outcomes of periodontal furcation defects by using platelet-rich fibrin (PRF) with other commonly utilized modalities. The eligibility criteria comprised randomized controlled trials (RCTs) comparing the clinical outcomes of PRF with those of other modalities for the treatment of furcation defects. Studies were classified into 11 categories in 3 different groups as follows: Group I (addition of PRF): (1) open flap debridement (OFD) alone versus OFD/PRF, (2) OFD/bone graft (OFD/BG) versus OFD/BG/PRF; Group II (comparative studies to PRF): (3) OFD/BG versus OFD/PRF, (4) OFD/collagen membrane versus OFD/PRF, (5) OFD/PRP versus OFD/PRF, (6) OFD/rhBMP2 versus OFD/PRF; and Group III (addition of biomaterial/biomolecule to PRF): OFD/PRF versus … (7) OFD/PRF/BG, (8) OFD/PRF/amniotic membrane (AM), (9) OFD/PRF/metformin, (10) OFD/PRF/bisphosphonates, (11) OFD/PRF/statins. Weighted means and forest plots were calculated for the reduction of probing pocket depth (PPD), gain of vertical and horizontal clinical attachment levels (VCAL and HCAL), gain in vertical and horizontal bone levels (VBL, HBL), and radiographic bone fill (RBF). From 45 articles identified, 21 RCTs reporting on class II furcations were included. The use of OFD/PRF and OFD/BG/PRF statistically significantly reduced PPD and improved VCAL and HCAL when compared to OFD or OFD/BG, respectively. The comparison between OFD/PRF alone versus OFD/BG, OFD/CM, OFD/PRP, or OFD/rhBMP2 led to similar outcomes for all investigated parameters, including a reduction in PPD, VCAL/HCAL gain, and RBF. The additional incorporation of a BG to OFD/PRF only mildly improved outcomes, whereas the addition of AM improved clinical outcomes. The addition of small biomolecules such as metformin, bisphosphonates, or statins all led to significant improvements in PPD, VCAL, and HCAL when compared to OFD/PRF alone. Noteworthy, a very high heterogeneity was found in the investigated studies. The use of PRF significantly improved clinical outcomes in class II furcation defects when compared to OFD alone, with similar levels being observed between OFD/PRF and/or OFD/BG, OFD/CM, OFD/PRP, or OFD/rhBMP2. Future research geared toward better understanding potential ways to enhance the regenerative properties of PRF with various small biomolecules may prove valuable for future clinical applications. Future histological research investigating PRF in human furcation defects is largely needed. The use of PRF in conjunction with OFD statistically significantly improved PPD, VCAL, and HCAL values, yielding comparable outcomes to commonly used biomaterials. The combination of PRF to bone grafts or the addition of small biomolecules may offer additional clinical benefits, thus warranting future investigation.

Influence of gender on periodontal outcomes: A retrospective analysis of eight randomized clinical trials.

AIMS: To explore the influence of gender on periodontal treatment outcomes in a dataset of eight RCTs conducted in Brazil, United States, and Germany. METHODS: Clinical parameters were compared between men and women with stages III/IV grades B/C generalized periodontitis at baseline and 1-year post-therapy, including scaling and root planing with or without antibiotics. RESULTS: Data from 1042 patients were analyzed. Men presented a tendency towards higher probing depth (p = .07, effect size = 0.11) and clinical attachment level (CAL) than women at baseline (p = .01, effect size = 0.16). Males also presented statistically significantly lower CAL gain at sites with CAL of 4-6 mm at 1-year post-therapy (p = .001, effect size = 0.20). Among patients with Grade B periodontitis who took antibiotics, a higher frequency of women achieved the endpoint for treatment (i.e., ≤4 sites PD ≥5 mm) at 1 year than men (p < .05, effect size = 0.12). CONCLUSION: Men enrolled in RCTs showed a slightly inferior clinical response to periodontal therapy in a limited number of sub-analyses when compared to women. These small differences did not appear to be clinically relevant. Although gender did not dictate the clinical response to periodontal treatment in this population, our findings suggest that future research should continue to explore this topic.

Efficacy of a novel three-step decontamination protocol for titanium-based dental implants: An in vitro and in vivo study.

AIM: The aim of the study was to evaluate several mechanical and chemical decontamination methods associated with a newly introduced biofilm matrix disruption strategy for biofilm cleaning and preservation of implant surface features. MATERIALS AND METHODS: Titanium (Ti) discs were obtained by additive manufacturing. Polymicrobial biofilm-covered Ti disc surfaces were decontaminated with mechanical [Ti curette, Teflon curette, Ti brush, water-air jet device, and Er:YAG laser] or chemical [iodopovidone (PVPI) 0.2% to disrupt the extracellular matrix, along with amoxicillin; minocycline; tetracycline; H2 O2 3%; chlorhexidine 0.2%; NaOCl 0.95%; hydrocarbon-oxo-borate-based antiseptic] protocols. The optimal in vitro mechanical/chemical protocol was then tested in combination using an in vivo biofilm model with intra-oral devices. RESULTS: Er:YAG laser treatment displayed optimum surface cleaning by biofilm removal with minimal deleterious damage to the surface, smaller Ti release, good corrosion stability, and improved fibroblast readhesion. NaOCl 0.95% was the most promising agent to reduce in vitro and in vivo biofilms and was even more effective when associated with PVPI 0.2% as a pre-treatment to disrupt the biofilm matrix. The combination of Er:YAG laser followed by PVPI 0.2% plus NaOCl 0.95% promoted efficient decontamination of rough Ti surfaces by disrupting the biofilm matrix and killing remnants of in vivo biofilms formed in the mouth (the only protocol to lead to ~99% biofilm eradication). CONCLUSION: Er:YAG laser + PVPI 0.2% + NaOCl 0.95% can be a reliable decontamination protocol for Ti surfaces, eliminating microbial biofilms without damaging the implant surface.

The Addition of Hydroxyapatite Nanoparticles on Implant Surfaces Modified by Zirconia Blasting and Acid Etching to Enhance Peri-Implant Bone Healing.

This study investigated the impact of adding hydroxyapatite nanoparticles to implant surfaces treated with zirconia blasting and acid etching (ZiHa), focusing on structural changes and bone healing parameters in low-density bone sites. The topographical characterization of titanium discs with a ZiHa surface and a commercially modified zirconia-blasted and acid-etched surface (Zi) was performed using scanning electron microscopy, profilometry, and surface-free energy. For the in vivo assessment, 22 female rats were ovariectomized and kept for 90 days, after which one implant from each group was randomly placed in each tibial metaphysis of the animals. Histological and immunohistochemical analyses were performed at 14 and 28 days postoperatively (decalcified lab processing), reverse torque testing was performed at 28 days, and histometry from calcified lab processing was performed at 60 days The group ZiHa promoted changes in surface morphology, forming evenly distributed pores. For bone healing, ZiHa showed a greater reverse torque, newly formed bone area, and bone/implant contact values compared to group Zi (p < 0.05; t-test). Qualitative histological and immunohistochemical analyses showed higher features of bone maturation for ZiHa on days 14 and 28. This preclinical study demonstrated that adding hydroxyapatite to zirconia-blasted and acid-etched surfaces enhanced peri-implant bone healing in ovariectomized rats. These findings support the potential for improving osseointegration of dental implants, especially in patients with compromised bone metabolism.

Effect of Processing Methods of Human Saliva on the Proteomic Profile and Protein-Mediated Biological Processes.

The use of saliva as a protein source prior to microbiological and biological assays requires previous processing. However, the effect of these processing methods on the proteomic profile of saliva has not been tested. Stimulated human saliva was collected from eight healthy volunteers. Non-processed saliva was compared with 0.22 µm filtered, 0.45 µm filtered, and pasteurized saliva, by liquid chromatography-mass spectrometry. Data are available via ProteomeXchange with identifier PXD039248. The effect of processed saliva on microbial adhesion was tested using bacterial and fungus species and in biological cell behavior using HaCaT immortalized human keratinocytes. Two hundred and seventy-eight proteins were identified in non-processed saliva, of which 54 proteins (≈19%) were exclusive. Saliva processing reduced identified proteins to 222 (≈80%) for the 0.22 µm group, 219 (≈79%) for the 0.45 µm group, and 201 (≈72%) for the pasteurized saliva, compared to non-processed saliva. The proteomic profile showed similar molecular functions and biological processes. The different saliva processing methods did not alter microbial adhesion (ANOVA, p > 0.05). Interestingly, pasteurized saliva reduced keratinocyte cell viability. Saliva processing methods tested reduced the proteomic profile diversity of saliva but maintained similar molecular functions and biological processes, not interfering with microbial adhesion and cell viability, except for pasteurization, which reduced cell viability.

Antimicrobial effect of platelet-rich fibrin: A systematic review of in vitro evidence-based studies.

This systematic review (SR) aimed to evaluate the antimicrobial potential of different types of platelet-rich fibrin (PRF) often used in regenerative treatments. An electronic search was performed in four databases and in Gray literature for articles published until January, 2023. The eligibility criteria comprised in vitro studies that evaluated the antimicrobial effect of different types of PRF. For the analysis of the risk of bias within studies, the modified OHAT (Office of Health Assessment and Translation) tool was used. For the evaluation of the results, a qualitative critical analysis was carried out in the synthesis of the results of the primary studies. Sixteen studies published between 2013 and 2021 were included in this SR. The antimicrobial effects of PRF variations (PRF, injectable PRF [I-PRF], PRF with silver nanoparticles [agNP-PRF], and horizontal PRF [H-PRF]), were analyzed against 16 types of bacteria from the oral, periodontal, and endodontic environments. All types of PRF showed significant antimicrobial action, with the antibacterial efficacy being more expressive than the fungal one. The I-PRF, H-PRF, and agNP-PRF subtypes improve antimicrobial activity. According to the OHAT analysis, no study was classified as having a high risk of bias. Evidence suggests that PRF variations have significant antimicrobial activity, with bacterial action being greater than fungal. Evolutions such as I-PRF, H-PRF, and agNP-PRF improve antimicrobial activity. Future studies analyzing the clinical effect of these platelets are fundamental. This SR was registered in INPLASY under number INPLASY202340016.

In-vitro polymicrobial oral biofilm model represents clinical microbial profile and disease progression during implant-related infections.

AIM: Clinically relevant in-vitro biofilm models are essential and valuable tools for mechanistically dissecting the etiopathogenesis of infectious diseases and test new antimicrobial therapies. Thus, the aim of this study was to develop and test a clinically relevant in-vitro oral polymicrobial biofilm model that mimics implant-related infections in terms of microbial profile. METHODS AND RESULTS: For this purpose, 24-well plate system was used to model oral biofilms, using three different microbial inoculums to grow in-vitro biofilms: (1) human saliva from periodontally healthy patients; (2) saliva as in inoculum 1 + Porphyromonas gingivalis strain; and (3) supra and subgingival biofilm collected from peri-implant sites of patients diagnosed with peri-implantitis. Biofilms were grown to represent the dynamic transition from an aerobic to anaerobic community profile. Subsequently, biofilms were collected after each phase and evaluated for microbiological composition, microbial counts, biofilm biomass, structure, and susceptibility to chlorhexidine (CHX). Results showed higher live cell count (P < .05) for biofilms developed from patients' biofilm inoculum, but biomass volume, dry weight, and microbiological composition were similar among groups (P > .05). Interestingly, according to the checkerboard DNA-DNA hybridization results, the biofilm developed from stimulated human saliva exhibited a microbial composition more similar to the clinical subgingival biofilm of patients with peri-implantitis, with proportions of the main pathogens closer to those found in the disease. In addition, biofilm developed using saliva as inoculum was shown to be susceptible to CHX with significant reduction in bacteria compared with biofilms without exposure to CHX (P < .05). CONCLUSION: The findings suggested that the in-vitro polymicrobial biofilm developed from human saliva as inoculum is a suitable model and clinically relevant tool for mimicking the microbial composition of implant-related infections.

A multifunctional guided surgery to assist in the 3-dimensional positioning of dental implants and in obtaining a palatal gingival graft.

Parameters such as the correct 3-dimensional positioning and the quality of peri-implant soft tissues are fundamental to the success of implant-supported restorations. Digital planning and guided surgery techniques can make the implant placement more accurate, and modifying the periodontal phenotype is often fundamental to increasing esthetics and peri-implant health, mainly in esthetic areas. This article describes a guided surgery technique that assists in the 3-dimensional positioning of implants and identifies the best anatomic area (volume and safety) for obtaining a palatal gingival graft.

Oral microbial colonization on titanium and polyetheretherketone dental implant healing abutments: An in vitro and in vivo study.

STATEMENT OF PROBLEM: Although polyetheretherketone (PEEK) implant healing abutments have become popular because of their esthetic, mechanical, and chemical properties, studies analyzing oral polymicrobial adhesion to PEEK abutments are lacking. PURPOSE: The purpose of this in vitro and in vivo study was to evaluate oral microbial adhesion and colonization on titanium (Ti) and PEEK healing abutments. MATERIAL AND METHODS: Ti (N=35) and PEEK substrates (N=35) were evaluated in vitro in terms of the initial adhesion (1 hour) or biofilm accumulation (48 hours) of Candida albicans and a polymicrobial inoculum using stimulated human saliva to mimic a diverse oral microbiome. Surface decontamination ability was evaluated after 24 hours of in vitro biofilm formation after exposure to an erbium-doped yttrium aluminum garnet (Er:YAG) laser. Conventional and flowable composite resin veneering on PEEK was also tested for microbial adhesion. In addition, an in vivo model with 3 healthy volunteers was conducted by using a palatal appliance containing the tested materials (3 or 4 specimens of each material per appliance) for 2 days to evaluate the effect of substrate on the microbial profile. Biofilms were evaluated by live cell counts and scanning electron microscopy images, and the microbial profile by Checkerboard deoxyribonucleic acid (DNA)-DNA hybridization. The t test and Mann-Whitney test were used to compare the groups (α=.05). RESULTS: PEEK and Ti materials showed similar fungal adhesion (P>.05). Although the PEEK surface limited the initial in vitro polymicrobial adhesion (approximately 2 times less) compared with Ti (P=.040), after 48 hours of biofilm accumulation, the microbial load was statistically similar (P=.209). Er:YAG laser decontamination was more effective on PEEK than on Ti surfaces, reducing approximately 11 times more microbial accumulation (P=.019). Both composite resins tested showed similar microbial adhesion (1 hour). In vivo, the PEEK material showed reduced levels of 6 bacterial species (P<.05), including the putative pathogen Treponema denticola. CONCLUSIONS: Although PEEK and Ti had similar bacterial and fungus biofilm attachment and accumulation, PEEK promoted a host-compatible microbial profile with a significantly reduced T. denticola load.

What is the impact of e-cigarettes on periodontal stem cells as revealed by transcriptomic analyses?

DESIGN: The research used an in vitro cell exposure model and multi-omics integration of transcriptome and epigenome profiling to compare the molecular effects of e-cigarettes and tobacco smoke on dental stem cells. AIM: The study aimed to compare the effects of e-cigarette and tobacco smoke on periodontal stem cells using a multi-omics approach to understand gene regulation. METHODS: This research studied primary human gingival mesenchymal stem cells (GMSCs) and periodontal ligament stem cells (PDLSCs) obtained from healthy donors. The cells were subjected to tobacco smoke, e-cigarette aerosol (both tobacco and menthol flavors), e-cigarette liquid (both tobacco and menthol flavors), or untreated conditions using an in vitro exposure system. RNA sequencing and bioinformatics analysis were used to profile the transcriptome and identify differential gene expression. Additionally, chromatin immunoprecipitation sequencing (ChIP-seq) was used to conduct genome-wide histone modification mapping for H3K27me3. Transcriptome profiling was combined with histone modification characterization to understand gene regulatory mechanisms. The study compared the effects of smoke versus e-cigarette, aerosol versus liquid exposure, and tobacco versus menthol flavor on gene expression and epigenetic landscapes in the two oral stem cell populations. RESULTS: The use of tobacco smoke caused damage to the DNA and nucleus in GMSCs, as well as mitochondrial dysfunction in PDLSCs. Regarding e-cigarettes, the aerosol and liquid affected non-coding RNA expression differently. The chemokine CXCL2 was found to be downregulated by aerosol but upregulated by liquid in GMSCs. An integrative analysis revealed that the upregulation of CXCL2 caused by e-liquid involved reduced H3K27me3 and activation of distal enhancers. On the other hand, aerosol exposure maintained H3K27me3 levels, while direct e-liquid exposure resulted in genome-wide reductions in H3K27me3, particularly in enhancer regions. Overall, the specific delivery methods and components of e-cigarettes caused unique changes in the transcriptome and epigenome of oral stem cells. CONCLUSIONS: E-cigarettes affect oral stem cells differently than tobacco smoke. Their aerosol and liquid have varying impacts on gene expression and regulatory landscapes in oral cells. Multi-omics approaches are important to understanding the molecular changes caused by e-cigarette components. This can help with toxicological assessments and determine their impact on periodontal health. Transcriptome and epigenome profiling are powerful tools to examine the unique molecular mechanisms involved in cellular responses to e-cigarettes.

Does implant location influence the risk of peri-implantitis?

Peri-implantitis is characterized by nonreversible and progressive loss of supporting bone and is associated with bleeding and/or suppuration on probing. Peri-implant disease is considered as the main etiologic factor related to implant failure. Peri-implant disease has a pathogenesis similar to that of periodontal disease, both being triggered by an inflammatory response to the biofilm accumulation. Although the prevalence of peri-implantitis has been evaluated by several clinical studies with different follow-ups, there are currently little data on the impact of implant location and the prevalence of peri-implantitis. The aim of this review, therefore, was to summarize the evidence concerning the prevalence of peri-implantitis in relation to implant location and associated risk predictors. Even though most studies evaluating the prevalence of peri-implantitis in relation to implant location are cross-sectional or retrospective, they suggest that the occurrence of peri-implantitis is most prevalent in the anterior regions of the maxilla and mandible. Moreover, it seems that there is a higher prevalence of peri-implantitis in the maxilla than in the mandible.

Systematic and scoping reviews to assess biological parameters.

INTRODUCTION: An evidence synthesis approach compiling biological/laboratory data is effective in advancing health-related knowledge. However, this approach is still underused in the oral health field. METHODS: This commentary discusses the opportunities and challenges of systematic and scoping reviews of laboratory data in dentistry. Special focus is on the potential of these reviews to elucidate etiological and treatment concepts of oral diseases, such as periodontitis and peri-implantitis. RESULTS: The following difficulties associated with such studies are discussed: (i) selection of ideal study design, (ii) assessment of "risk of bias" and definition of "certainty of evidence", (iii) evidence assembly and summary, and (iv) the paper review process. DISCUSSION: Despite those challenges, high-quality reviews integrating laboratory data may generate relevant scientific information and help identify new avenues for future investigations. Experts in different oral health topics should build a process capable of helping researchers assemble and interpret these types of data.

Do the progression of experimentally induced gingivitis and peri-implant mucositis present common features? A systematic review of clinical human studies.

This systematic review evaluated the features of the progression of experimentally induced gingivitis and peri-implant mucositis in humans. Included were studies that evaluated clinical, immunological, or microbiological responses between experimentally induced gingivitis and peri-implant mucositis in periodontally healthy patients. A total of 887 articles were initially identified, but only 12 were included in the final analysis. Implants accumulate less biofilm and suffer the most heterogeneous alterations in the microbiota, in the abstinence of oral hygiene, compared with the tooth. Interestingly, although dental implants presented less biofilm accumulation, the peri-implant mucosa showed a more exacerbated clinical response than the gingival tissue. The risk of bias of the selected studies was moderate to low, with one study presenting serious risk. The progression events of peri-implant mucositis were similar to those of experimental gingivitis but led to a different host response. This review was registered in the PROSPERO database CRD420201 123360.

Delphi Project on the trends in Implant Dentistry in the COVID-19 era: Perspectives from Latin America.

AIM: To establish trends in Implant Dentistry in Latin America in the COVID-19 pandemic. MATERIAL AND METHODS: A steering committee and an advisory group of experts in Implant Dentistry were selected among eighteen countries. An open-ended questionnaire by Delphi methodology was validated including 64 questions, divided in 7 topics, concerning the various trends in dental implantology. The survey was conducted in two rounds, which provided the participants in the second round with the results of the first. The questionnaires were completed on August 2020, and the online meeting conference was held on September 2020. The final prediction was developed through consensus by a selected group of experts. RESULTS: A total of 197 experts from Latin America answered the first and second questionnaire. In the first round, the established threshold for consensus (65%) was achieved in 30 questions (46.87%). In the second round, performed on average 45 days later, this level was achieved in 47 questions (73.43%). Consensus was completely reached on the item "Diagnostic" (100%), the field with the lowest consensus was "Demand for treatment with dental implants" (37.5%). CONCLUSIONS: The present study in Latin America has provided relevant and useful information on the predictions in the education and practice of Implant Dentistry in the COVID-19 era. The consensus points toward a great confidence of clinicians in the biosecurity protocols used to minimize the risk of SARS-CoV-2 transmission. It is foreseen as an important change in education, with introduction of virtual reality and other simulation technologies in implant training.

Treg and TH17 link to immune response in individuals with peri-implantitis: a preliminary report.

BACKGROUND AND OBJECTIVES: Treg and TH17 cells influence the inflammatory process in periodontal diseases and could also play in a similar pattern, an essential role in immune-inflammatory mechanisms involved in the destruction of the peri-implant tissues, peri-implantitis. Therefore, this study evaluated the levels of RORγT and FOXP3 gene expression in subjects with peri-implantitis and healthy peri-implant tissues. METHODS: A total of 35 subjects with implant-supported restorations in both diseased and healthy clinical conditions (n = 15 healthy; n = 20 peri-implantitis) were included in this study. Peri-implantitis was defined as probing depth > 5 mm, bleeding on probing and/or suppuration, and peri-implant bone loss >4 mm. Peri-implant tissue biopsies were collected for analysis of the mRNA, RORγT, and FOXP3 expression levels. The samples were submitted to total RNA extraction, treatment with DNAse, and cDNA synthesis. Subsequently, real-time PCR reaction was performed to evaluate the levels of RORγT and FOXP3 gene expression to the reference gene. These were analyzed by the non-parametric Mann-Whitney method with a level of significance of 5%. RESULTS: Higher gene expression levels of the transcription factors RORγT and FOXP3 were detected in the tissues affected by peri-implantitis when compared with healthy tissues (p < 0.05). CONCLUSIONS: The present study demonstrated the possible existence of a hybrid TH17-Treg profile, based on the gene expression of transcription factors inducing differentiation of these cells. Further studies must be designed to gain a better understanding of the immunological mechanisms involved in the pathogenesis of peri-implantitis. CLINICAL RELEVANCE: The levels of RORγT and FOXP3 transcription factors that were linked to cells with the FOXP3+RORγT+ phenotype could be used as a predictor of peri-implantitis progression.

Lateral static overload on immediately restored implants decreases the osteocyte index in peri-implant bone: a secondary analysis of a pre-clinical study in dogs.

OBJECTIVES: This animal study was conducted to evaluate the osteocyte index in the peri-implant bone around immediately restored implants under static lateral overload. MATERIAL AND METHODS: Seven mongrel dogs received three implants on each side of the mandible. Forty-two implants were distributed into three groups (14 implants per group); each animal received two implants connected to a 4.5-mm opened expansion device (experimental group); in the other mandible side, two implants were connected into an expansion device without activation (control group); one implant each side of the mandible was left submerged (unload group). After 4 months under daily mechanical and chemical plaque control, the animals were euthanized; dental implants and surrounding bone were removed and processed to obtain thin ground sections. Histomorphometry was used to evaluate the osteocyte index in the peri-implant bone contact to implant. RESULTS: A higher, statistically significant mean number of osteocytes × 10-5 µm2 (54.74 ± 23.91) was found in the control group compared with the test group (22.57 ± 22.55) (p = 0.0221). The correlation between percentage of bone-implant contact and osteocyte index for submerged implants was not statistically significant (p = 0.2667), whereas the value for immediately loaded implants was statistically significant (p = 0.0480). CONCLUSION: The lower number of osteocytes in the peri-implant bone around overloaded implants could be related to the need for functional adaptation of the bone tissue to overloading and to the hypothesized involvement of the osteocytes in the maintenance of the bone matrix in the control group. CLINICAL RELEVANCE: Osteocytes play a pivotal role in bone adaptation to mechanical loading, and the osteocyte network has been regarded as being the main mechanosensory mechanism.

Metabolic activity of hydro-carbon-oxo-borate on a multispecies subgingival periodontal biofilm: a short communication.

OBJECTIVE: This study evaluated the metabolic activity of hydro-carbon-oxo-borate complex (HCOBc) on a multispecies subgingival biofilm as well as its effects on cytotoxicity. MATERIALS AND METHODS: The subgingival biofilm with 32 species related to periodontitis was formed in the Calgary Biofilm Device (CBD) for 7 days. Two different therapeutic schemes were adopted: (1) treatment with HCOBc, 0.12% chlorhexidine (CHX), and negative control group (without treatment) from day 3 until day 6, two times a day for 1 min each time, totaling 8 treatments and (2) a 24-h treatment on a biofilm grown for 6 days. After 7 days of formation, biofilm metabolic activity was determined by colorimetry assay, and bacterial counts and proportions of complexes were determined by DNA-DNA hybridization. Both substances' cytotoxicity was evaluated by cell viability (XTT assay) and clonogenic survival assay on ovary epithelial CHO-K1 cells and an osteoblast precursor from calvaria MC3T3-E1 cells. RESULTS: The first treatment scheme resulted in a significant reduction in biofilm's metabolic activity by means of 77% by HCOBc and CHX treatments versus negative control. The total count of 11 and 25 species were decreased by treatment with hydro-carbon-oxo-borate complex and CHX, respectively, compared with the group without treatment (p < 0.05), highlighting a reduction in the levels of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Fusobacterium periodontium. CHX significantly reduced the count of 10 microorganisms compared to the group treated with HCOBc (p < 0.05). HCOBc and CHX significantly decreased the pathogenic red-complex proportion compared with control-treated biofilm, and HCOBc had even a more significant effect on the red complex than CHX had (p ≤ 0.05). For the second treatment scheme, HCOBc complex and CHX significantly decreased 61 and 72% of control biofilms' metabolic activity and the counts of 27 and 26 species, respectively. HCOBc complex did not significantly affect the proportions of formed biofilms, while CHX significantly reduced red, orange, and yellow complexes. Both substances exhibited similar cytotoxicity results. CONCLUSIONS: This short communication suggested that the HCOBc complex reduced a smaller number of bacterial species when compared to chlorhexidine during subgingival biofilm formation, but it was better than chlorhexidine in reducing red-complex bacterial proportions. Although HCOBc reduced the mature 6-day-old subgingival multispecies biofilms, it did not modify bacterial complexes' ratios as chlorhexidine did on the biofilms mentioned above. Future in vivo studies are needed to validate these results. CLINICAL RELEVANCE: HCOBc complex could be used to reduce red-complex periodontal bacterial proportions.

Assessment of the reproducibility and precision of milling and 3D printing surgical guides.

BACKGROUND: Technology advancement has rising in the past decade and brought several innovations and improvements. In dentistry, this advances provided more comfortable and quick procedures to both the patient and the dental surgeon, generating less predictability in the final result. Several techniques has been developed for the preparation of surgical guides aiming at the optimization of surgical procedures. The present study aimed to evaluate the reproducibility and precision of two types of surgical guides obtained using 3D printing and milling methods. METHODS: A virtual model was developed that allowed the virtual design of milled (n = 10) or 3D printed (n = 10) surgical guides. The surgical guides were digitally oriented and overlapped on the virtual model. For the milling guides, the Sirona Dentsply system was used, while the 3D printing guides were produced using EnvisionTEC's Perfactory P4K Life Series 3D printer and E-Guide Tint, a biocompatible Class I certified material. The precision and trueness of each group during overlap were assessed. The data were analyzed with GraphPad software using the Kolmogorov-Smirnov test for normality and Student's t test for the variables. RESULTS: The Kolmogorov-Smirnov test showed a normal distribution of the data. Comparisons between groups showed no statistically significant differences for trueness (p = 0.529) or precision (p = 0.3021). However, a significant difference was observed in the standard deviation of mismatches regarding accuracy from the master model (p < 0.0001). CONCLUSIONS: Within the limits of this study, surgical guides fabricated by milling or prototyped processes achieved similar results.

Antimicrobial effects of a pulsed electromagnetic field: an in vitro polymicrobial periodontal subgingival biofilm model.

The objective was to test the influence of a pulsed electromagnetic field (PEMF) on bacterial biofilm colonization around implants incorporated with healing abutments. Healing abutments with (test group) and without (control group) active PEMF devices were placed in a multispecies biofilm consisting of 31 different bacterial species. The biofilm composition and total bacterial counts (x105) were analyzed by checkerboard DNA-DNA hybridization. After 96 h, the mean level of 7 out of the 31 bacterial species differed significantly between groups, namely Eubacterium nodatum, Fusobacterium nucleatum ssp. nucleatum, Streptococcus intermedius, Streptococcus anginosus, Streptococcus mutans, Fusobacterium nucleatum ssp. Vicentii and Capnocytophaga ochracea were elevated in the control group (p < 0.05). The mean total bacterial counts were lower in the Test group vs the control group (p < 0.05). An electromagnetic healing cap had antimicrobial effects on the bacterial species and can be used to control bacterial colonization around dental implants. Further clinical studies should be conducted to confirm these findings.

Effectiveness of connective tissue graft substitutes for the treatment of gingival recessions compared with coronally advanced flap: a network meta-analysis.

OBJECTIVES: This study aimed to conduct a network comparison of the clinical effect of connective tissue graft (CTG) substitutes on the treatment of gingival recessions using coronally advanced flap. MATERIALS AND METHODS: An electronic search without language or dates restrictions was performed in five databases and in Grey literature for articles published until May, 2020. The eligibility criteria comprised randomized controlled trials (RCTs) that analyzed the clinical outcomes of CTG substitutes when compared with coronally advanced flap (CAF) for the treatment of Miller class I and II (Cairo RT I) gingival recessions. A pairwise and network meta-analysis were conducted for each periodontal parameters to assess and compare the outcomes among different treatment arms for the primary and secondary outcomes. This systematic review (SR) was registered in INPLASY under number INPLASY202060075. RESULTS: Twenty-seven studies were included in the present SR. All analyzed CTG substitutes showed superior results when comparing with CAF alone for all periodontal parameters. However, when compared in a network, the acellular dermal matrix (ADM) demonstrated the best treatment ranking of probability results, followed by platelet-rich fibrin (PRF), enamel matrix derivative (EMD), and xenogeneic collagen matrix (XCM) for root coverage (RC). CONCLUSION: This SR observed that the association of biomaterials increases the effectiveness of RC in comparison with CAF alone. Based on the treatment ranking, although all the biomaterials analyzed showed a positive effect for RC, the ADM demonstrated the best results. CLINICAL RELEVANCE: To know the effectiveness of CTG substitutes for the treatment of gingival recessions.