Volumetric changes in free gingival graft and gingival unit graft treatments evaluated using an indirect digital method.

BACKGROUND: The aim of this study was to evaluate clinical one-dimensional changes such as root surface coverage, decrease seen in the amount of gingival recession and keratinised gingival width (KGW) obtained throughout a 6-month follow-up period following the treatment of Cairo class II gingival recession with free gingival graft (FGG) and gingival unit graft (GUG). Three-dimensional changes in gingival volume and thickness were also compared digitally using an indirect method. METHODS: A total of 20 patients with localised Cairo class II gingival recession were randomly separated into two groups; 10 patients were treated with FGG and 10 patients treated with GUG. Preoperatively and at 6 months postoperatively, the initial position of the gingiva and KGW were recorded for all the patients and plaster models were formed from the obtained impressions with the traditional method. The plaster models were transferred to a digital environment by scanning with a model scanner. Using a software program, changes in gingival papillary height and gingival volume and thickness were compared between the groups and according to the baseline values from The Standard Tessellation Language (STL) files obtained. RESULTS: Compared to the baseline values, a significant increase was determined in the KGW, and a significant decrease in pocket depth, clinical attachment level, and gingiva recession depth in all the groups (p<0.05). No statistically significant difference was determined between the groups in respect of the changes in mean gingiva thickness, gingiva volume, and mean vertical papillary height (p>0.05). CONCLUSION: The study results showed that GUG treatment for Cairo class II localised gingival recession is an effective method in respect of increasing gingiva volume and thickness, increasing KGW, coverage of the root surface, and forming tissue contours that allow the patient to easily maintain oral hygiene. However, there was not seen to be any adventage of GUG and FGG over each other.

Can delta neutrophil index values predict the success of periodontal treatment in patients with periodontitis?

OBJECTIVES: The aim of this study was to evaluate the effect of delta neutrophil index (DNI) on non-surgical periodontal therapy (NSPT), whose role has been documented in the pathogenesis and follow-up of periodontal disease. METHODS AND MATERIALS: The study included 35 patients with stage 3, grade A periodontitis (test group) and 35 patients without periodontal disease (control group). Initially, periodontal parameters were recorded and blood samples were taken from all patients. For patients with periodontitis, periodontal parameter measurements and blood sample analyses were repeated 3 months after NSPT. RESULTS: After NSPT, DNI, CRP (C-reactive protein), neutrophil count, WBC (white blood cell), and neutrophil-lymphocyte ratio (NLR) values decreased in the test group, but did not reach a statistically significant level (p > 0.05). When the inflammatory variables were examined, significantly higher CRP, IG (immature granulocytes), DNI, neutrophil count, and WBC were observed in the test group compared to the control group (p < 0.05). In the test group, periodontal parameters were lower 3 months after NSPT than at baseline (p < 0.05). CONCLUSION: Consistent with previous findings in the literature, the patients with periodontitis were determined to have higher levels of DNI, CRP, neutrophils, and WBC, compared to the individuals without periodontitis. Although a decrease was seen in DNI after NSPT, this was not at a significant level. CLINICAL RELEVANCE: DNI is a guide in the evaluation of inflammation at the onset of periodontal disease, but studies with a larger number of cases are needed to use these parameters in the evaluation of treatment success. TRIAL REGISTRATION: This study was retrospectively registered on December 27, 2022, with the number NCT05666622 at http://www. CLINICALTRIALS: gov .

Pilus PilA of the naturally competent HACEK group pathogen Aggregatibacter actinomycetemcomitans stimulates human leukocytes and interacts with both DNA and proinflammatory cytokines.

Each HACEK group pathogen, which can cause infective endocarditis, expresses type IVa pili. The type IVa major pilin PilA plays a role in bacterial colonization, virulence, twitching motility, and the uptake of extracellular DNA. The type IV prepilin homolog PilA of the periodontal pathogen A. actinomycetemcomitans (AaPilA) is linked to DNA uptake and natural competence. Our aim was to investigate the virulence properties and immunogenic potential of AaPilA. Since Neisseria meningitidis PilE, which shares sequence similarity with AaPilA, participates in sequestering host cytokines, we examined the ability of AaPilA to interact with various cytokines. Moreover, we investigated the structural characteristics of AaPilA with molecular modeling. AaPilA was conserved among A. actinomycetemcomitans strains. One of the 18 different natural variants, PilAD7S, is present in naturally competent strains. This variant interacted with DNA and bound interleukin (IL)-8 and tumor necrosis factor (TNF)-α. Specific anti-AaPilA antibodies were present in A. actinomycetemcomitans-positive periodontitis patient sera, and the production of reactive oxygen species from human neutrophils was less effectively induced by the ΔpilA mutant than by the wild-type strains. However, AaPilA did not stimulate human macrophages to produce proinflammatory cytokines, nor was it cytotoxic. The results strengthen our earlier hypothesis that the DNA uptake machinery of A. actinomycetemcomitans is involved in the sequestration of inflammatory cytokines. Furthermore, AaPilA stimulates host immune cells, such as B cells and neutrophils, making it a potential virulence factor.

Evaluation of the effects of platelet-rich fibrin, concentrated growth factors, and autologous fibrin glue application on wound healing following gingivectomy and gingivoplasty operations: a randomized controlled clinical trial.

OBJECTIVE: The aim of this study was to evaluate the effect of platelet-rich fibrin (PRF), concentrated growth factors (CGF), and autologous fibrin glue (AFG) application on early wound healing after gingivectomy and gingivoplasty operations. METHOD AND MATERIALS: In this split-mouth study, gingivectomy and gingivoplasty surgery were performed on 19 patients. The postoperative PRF, CGF, and AFG applied areas were compared with the control regions. On days 0, 7, 14, and 28, the surgical area was stained with a plaque-disclosing agent and evaluated in the ImageJ program. Wound healing was evaluated with H2O2 test, visual analog scale for pain, and Landry, Turnbull, and Howley (LTH) wound healing index on days 7, 14, and 28. The patients were asked to evaluate their esthetic perceptions on a visual analog scale. RESULTS: The amount of staining at days 7 and 14 was found to be significantly higher in the control group than in the test groups, but there was no difference between the test groups. LTH index values of the control group at days 7, 14, and 28 were found to be significantly lower than the test groups. There was no significant difference between the groups in the epithelialization assessment performed with the H2O2 test. It was observed that the use of platelet concentrate at day 7 reduced postoperative early pain. Patients were highly satisfied with postoperative esthetics. CONCLUSION: After gingivectomy and gingivoplasty operations, PRF, CGF, and AFG application were found to have positive effects on wound healing. However, PRF, CGF, and AFG applications were not superior to each other in terms of secondary wound healing.

High-Resolution XFEL Structure of the Soluble Methane Monooxygenase Hydroxylase Complex with its Regulatory Component at Ambient Temperature in Two Oxidation States.

Soluble methane monooxygenase (sMMO) is a multicomponent metalloenzyme that catalyzes the conversion of methane to methanol at ambient temperature using a nonheme, oxygen-bridged dinuclear iron cluster in the active site. Structural changes in the hydroxylase component (sMMOH) containing the diiron cluster caused by complex formation with a regulatory component (MMOB) and by iron reduction are important for the regulation of O2 activation and substrate hydroxylation. Structural studies of metalloenzymes using traditional synchrotron-based X-ray crystallography are often complicated by partial X-ray-induced photoreduction of the metal center, thereby obviating determination of the structure of the enzyme in pure oxidation states. Here, microcrystals of the sMMOH:MMOB complex from Methylosinus trichosporium OB3b were serially exposed to X-ray free electron laser (XFEL) pulses, where the ≤35 fs duration of exposure of an individual crystal yields diffraction data before photoreduction-induced structural changes can manifest. Merging diffraction patterns obtained from thousands of crystals generates radiation damage-free, 1.95 Å resolution crystal structures for the fully oxidized and fully reduced states of the sMMOH:MMOB complex for the first time. The results provide new insight into the manner by which the diiron cluster and the active site environment are reorganized by the regulatory protein component in order to enhance the steps of oxygen activation and methane oxidation. This study also emphasizes the value of XFEL and serial femtosecond crystallography (SFX) methods for investigating the structures of metalloenzymes with radiation sensitive metal active sites.

Genetic Algorithm Based Design and Experimental Characterization of a Highly Thermostable Metalloprotein.

The development of thermostable and solvent-tolerant metalloproteins is a long-sought goal for many applications in synthetic biology and biotechnology. In this work, we were able to engineer a highly thermostable and organic solvent-stable metallo variant of the B1 domain of protein G (GB1) with a tetrahedral zinc binding site reminiscent of the one of thermolysin. Promising candidates were designed computationally by applying a protocol based on classical and first-principles molecular dynamics simulations in combination with genetic algorithm optimization. The most promising of the computationally predicted mutants was expressed and structurally characterized and yielded a highly thermostable protein. The experimental results thus confirm the predictive power of the applied computational protein engineering approach for the de novo design of highly stable metalloproteins.

Can Biomimetic Zinc Compounds Assist a (3 + 2) Cycloaddition Reaction? A Theoretical Perspective.

Compounds bearing tetrazole rings are valuable facets in numerous branches of chemistry including metabolic imaging and the production of drugs and high-energy materials. Synthesis of tetrazoles with the help of organocatalysts has intensively been explored, while enzyme-directed click chemistry has attracted less attention and was only used in inhibitor design so far. Herein, we have investigated the possibility of a biomimetic catalyst based on a Lewis acid approach by exploring the anionic cycloaddition of azide and acetonitrile catalyzed by ZnBr2 in comparison with different biomimetic Zn(II) models. Density functional based calculations in the gas phase and with implicit solvation indicate that a variety of bioinspired zinc complexes should be able to catalyze tetrazole formation with catalytic enhancements comparable to zinc bromide salts. Such bioinspired routes could provide new possibilities for the stereo- and regioselectively controlled synthesis of tetrazoles.

Medium-Ring Effects on the Endo/Exo Selectivity of the Organocatalytic Intramolecular Diels-Alder Reaction.

The intramolecular Diels-Alder reaction has been used as a powerful method to access the tricyclic core of the eunicellin natural products from a number of 9-membered-ring precursors. The endo/exo selectivity of this reaction can be controlled through a remarkable organocatalytic approach, employing MacMillan's imidazolidinone catalysts, although the mechanistic origin of this selectivity remains unclear. We present a combined experimental and density functional theory investigation, providing insight into the effects of medium-ring constraints on the organocatalyzed intramolecular Diels-Alder reaction to form the isobenzofuran core of the eunicellins.

Lessons from nature: computational design of biomimetic compounds and processes.

Through millions of years of evolution, Nature has accomplished the development of highly efficient and sustainable processes and the idea to understand and copy natural strategies is therefore very appealing. However, in spite of intense experimental and computational research, it has turned out to be a difficult task to design efficient biomimetic systems. Here we discuss a novel strategy for the computational design of biomimetic compounds and processes that consists of i) target selection; ii) atomistic and electronic characterization of the wild type system and the biomimetic compounds; iii) identification of key descriptors through feature selection iv) choice of biomimetic template and v) efficient search of chemical and sequence space for optimization of the biomimetic system. As a proof-of-principles study, this general approach is illustrated for the computational design of a 'green' catalyst mimicking the action of the zinc metalloenzyme Human Carbonic Anhydrase (HCA). HCA is a natural model for CO2 fixation since the enzyme is able to convert CO2 into bicarbonate. Very recently, a weakly active HCA mimic based on a trihelical peptide bundle was synthetized. We have used quantum mechanical/molecular mechanical (QM/MM) Car-Parrinello simulations to study the mechanisms of action of HCA and its peptidic mimic and employed the obtained information to guide the design of improved biomimetic analogues. Applying a genetic algorithm based optimization procedure, we were able to re-engineer and optimize the biomimetic system towards its natural counter part. In a second example, we discuss a similar strategy for the design of biomimetic sensitizers for use in dye-sensitized solar cells.