Pilus islets and the clonal spread of piliated Streptococcus pneumoniae: a review

Pneumococci are a common cause of severe infections, such as otitis media, pneumonia, meningitis and bacteremia. Pili are detected in a small proportion of pneumococcal population, but these structures have recently been associated with bacterial virulence in humans. Therefore, the epidemiological relationships between pneumococcal pili, serotype and antimicrobial resistance are of interest. This study aims to discuss the virulence contribution of the Streptococcus pneumoniae pili and the epidemiological relationships among the pilus genes, antimicrobial resistance trends, regional serotypes and genotypic variations. Previous reports have characterized the pneumococcal pilus islet as a clonal feature in the pneumococcal serotypes that are covered by the pneumococcal conjugate vaccine (PCV), including serotypes 19A, 19F, 23F and 7F. Many of the pneumococcal molecular epidemiology network (PMEN) clones are piliated isolates that are also strongly associated with a high frequency of multidrug resistance. Most of these piliated pneumococcal isolates belong to a few clonal complexes (CC), such as CC320, CC199, CC271, CC191 and CC156. Additional molecular epidemiology and genomic studies, particularly whole genome sequence analysis (WGS), are needed to develop an in-depth understanding of the piliated pneumococcal isolates

Root-crown ratios of permanent teeth in Malay patients attending HUSM Dental Clinic

Keywords Crown height, Permanent teeth, Root length, Root-crown ratio. Abstract The objectives of this study were to determine the normal mean value of the root-crown (R/C ratios) in Malay patients and their variations by gender and dental arch from orthopantomogram radiographs (OPGs). Two thousand nine hundred and twenty teeth with fully developed roots were measured from 112 OPGs. Subjects with history of maxillofacial trauma or orthodontic therapy were excluded. The mean age of the subjects was 19.1 (SD 2.08) years old for males while females 18.9 (SD 2.19) years old in the range from 15 to 22 years old. The intra-examiner reproducibility of the assessment method was good (Intraclass correlation coefficient 0.81). Results of this study showed that there was no significant difference between R/C ratios of males and females groups. However, the ratios of the antagonist teeth for both males and females were significantly greater in the mandible than in the maxilla (p<0.05 for right and left lateral incisors and right first premolars in male; p<0.001 for all other teeth). In both gender, the highest R/C ratio was mandibular second premolars and the lowest R/C ratio were maxillary central incisors. The rootcrown ratio could be used as a baseline data and reference to help in orthodontic diagnosis, treatment planning and prognosis as well as evaluation developmental root deficiency

Socket preservation using acellular dermal matrix allograft in combination with xenograft for dental implant placement in Anterior Maxilla: a case report

The collapse of alveolar ridge following tooth extraction is a physiological process which may complicate subsequent implant placement and restoration especially in the aesthetic zone. This case report describes the use of an acellular dermal matrix graft (Alloderm®, Biohorizon, USA) in combination with bovine bone graft (Bio-Oss®, Geistlich, Switzerland) immediately after tooth extraction for soft and hard tissue augmentation prior to implant placement in the anterior maxilla. The eighth year follow-up demonstrated an acceptable aesthetic outcome indicating that this approach may be employed where tooth extraction is indicated and replacement with implant-supported prosthesis is anticipated particularly in the anterior aesthetic zone region

Periodontal parameters and salivary levels of receptor activator of NF-kB Ligand and osteoprotegerin in obese periodontitis patients

This study aimed to assess levels of salivary receptor activator of nuclear factor kappa-B (RANKL) and osteoprotegerin (OPG) protein biomarkers in obese patients with periodontitis. Subjects were divided into two groups: group-I consisted of 30 non-obese subjects with periodontitis, while group-II consisted of 30 obese patients with periodontitis. The periodontal examination, including periodontal pocket depth (PPD), clinical attachment loss (CAL), plaque score (PS), and gingival bleeding index (GBI), were evaluated. Salivary RANKL and OPG were estimated in both study groups using an enzyme-linked immunosorbent assay. Levels of RANKL protein were significantly higher in the obese group than the non-obese group, while levels of OPG protein were significantly higher in the non-obese group than the obese group. The periodontal parameters PPD, CAL, and PS, except for GBI, showed a significant difference between the two groups. The mean PPD scores were significantly higher in the obese group than the non-obese group, while the CAL scores in the obese group were significantly higher than the non-obese group. Only the salivary OPG levels were significantly associated with CAL. There is an association of OPG and CAL in both obese and non-obese with periodontitis

Evaluation of the human amniotic membrane as a scaffold for periodontal ligament fibroblast attachment and proliferation

This study was aimed at evaluating the ability of the human amniotic membrane (HAM) to act as a scaffold for the growth of the main cells in periodontal regeneration, human periodontal ligament fibroblasts (HPDLFs). The HAM has many biological properties that are suitable for periodontal tissue regeneration such as low immunogenicity, anti-fibrosis, anti-inflammation, and a rich extracellular matrix component. Commercially available HPDLFs were seeded onto the HAM, and the attachment and proliferation of the cells were observed through scanning electron microscopy (SEM) and histological analysis. Cell viability was assessed using the alamarBlue® proliferation assay at days 1, 3, 7, 14 and 21. Histologically, the HPDLFs showed a monolayer to multilayer attachment onto the HAM from day 1 to day 7. The SEM analysis demonstrated that the HPDLFs had attached appropriately onto the HAM surface at day 1 to day 3, and began overlapping at day 7, while maintaining their flat shape. However, by days 14 and 21, there was an alteration in the morphology of the cells, where they later became rounded. The proliferation assay showed that the viability of the HPDLFs on the HAM had increased significantly from day 1 to day 7 (p=0.012), but later showed significant reduction at day 14 (p=0.002) and day 21 (p=0.005). In conclusion, this study showed that the HAM was able to function well as a scaffold for HPDLFs within 7 days, and thus, it can be a promising scaffold for periodontal regeneration. However, the behaviour of the cells in relation to the membrane over longer culture duration warrants further investigation

In-vitro antimicrobial effectiveness of herbal-based mouthrinses against oral microorganisms

Objective: To evaluate the in vitro antimicrobial effectiveness of commercial herbal-based mouthrinses against oral microorganisms. Methods: A total of three mouthrinses (OX, Pesona and Watsons) were tested for their antimicrobial activity against six oral organisms, Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Lactobacillus salivarius (L. salivarius), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Candida albicans (C. albicans) by standard agar-disk diffusion assay. Oradex mouthrinse containing 0.12% chlorhexidine gluconate and sterile distilled water was served as positive and negative controls, respectively. Results: All mouthrinse formulations were effective in inhibiting the growth of S. mutans, S. sobrinus, L. salivarius and C. albicans. Among the tested mouthrinses, Pesona was the only effective mouthrinse against S. aureus and P. aeruginosa, similar to Oradex mouthrinse. Pesona mouthrinse formulation appears to be as effective as Oradex mouthrinse formulation to kill S. aureus and P. aeruginosa. Statistical analysis showed no significant difference among the tested formulations regarding their antimicrobial activities (P > 0.05). Conclusions: Pesona was not the only herbal mouthrinse effective in inhibiting the growth of S. mutans, S. sobrinus, L. salivarius and C. albicans in vitro. All tested formulations were effective against those strains. Our findings may serve as a guide for selecting a kind of herbal mouthrinses as well as providing information to the dental professionals about the efficacy of these products

Distribution of FC gamma receptor IIa genotypes among Malay patients with periodontitis

To evaluate the distribution of Fc gamma receptor IIa (FcγRIIa) gene polymorphism and its possible association with periodontitis in Malay patients. Materials and Methods: Periodontal parameters were recorded in 53 periodontitis and 65 healthy (control) subjects. Samples for genotype analysis were obtained from the buccal cheek mucosa. The FcγRIIa genotypes were determined via nested polymerase chain reaction by using sequence specific primers. Results: The FcγRIIa R/H131 genotype showed the highest prevalence (56.6% in periodontitis and 50.8% in control) by which the H131 allele was slightly dominant in all subjects (51% in periodontitis and 52% in control). However, no significant association was observed between the periodontal parameters and FcγRIIa genotypes (p>0.05). Conclusion: Within the study limitations, FcγRIIa R/H131 genotype was mostly distributed in Malay subjects. There is no significant association between FcγRIIa gene polymorphisms with periodontiti

Mechanical Properties of PCL/PLA Composite Sample Produce from 3D Printer and Injection Molding

Currently there are a lot of studies have been carried out regarding on composite material that can be used for 3D printing. The main reasons is to minimize the cost related to the molds that need to be prepared for injection molding. The question is how far will be the differences in term of mechanical properties for part produce from this 2 techniques. This study are done to investigate the mechanical properties of PCL/PLA composite sample prepared from Fused Deposition Modelling (FDM) 3D printer. The mechanical properties that were evaluated are tensile, flexural and impact. The result were later compared with samples produced from injection molding. The dimensional accuracy result shows a very minimal percentage error on samples produced using 3D printer for mechanical testing. The parameter of 3D printer used to produce sample was 136°C print temperature, 0.12mm deposition of height, 20mm/s print speed and 22mm/s travel speed. The mechanical properties of PCL/PLA prepared by injection molding generally came superior in all the conducted test if compared to those of 3D printer. Tensile strength result showed that injection molding value was higher than 3D printer which is 10MPa and 6.513MPa respectively. The results of tensile strength and modulus of elasticity showed injection molding ware better than 3D printing with value of 118.26MPa and 61.223MPa respectively. For flexural strength, the highest values were injection molding which is 7.59MPa while 3D printing is 4.96Mpa. While the highest for flexural modulus are 35.33GPa for injection molding and 30.911GPa for 3D printing. Impact strength for PCL/PLA sample was 1.33 Joule for injection molding and 0.543 Joule for 3D printer method

Potential Effects of Non-Surgical Periodontal Therapy on Periodontal Parameters, Inflammatory Markers, and Kidney Function Indicators in Chronic Kidney Disease Patients with Chronic Periodontitis

Chronic kidney disease (CKD) and chronic periodontitis (CP) contribute to the increased level of inflammatory biomarkers in the blood. This study hypothesized that successful periodontal treatment would reduce the level of inflammatory biomarkers in CKD patients. This prospective study recruited two groups of CP patients: 33 pre-dialysis CKD patients and 33 non-CKD patients. All patients underwent non-surgical periodontal therapy (NSPT). Their blood samples and periodontal parameters were taken before and after six weeks of NSPT. The serum level of high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and periodontal parameters were compared between groups. On the other hand, kidney function indicators such as serum urea and estimated glomerular filtration rate (eGFR) were only measured in CKD patients. Clinical periodontal parameters and inflammatory markers levels at baseline were significantly higher (p < 0.05) in the CKD group than in the non-CKD group and showed significant reduction (p < 0.05) after six weeks of NSPT. CKD patients demonstrated a greater periodontitis severity and higher inflammatory burden than non-CKD patients. Additionally, CKD patients with CP showed a good response to NSPT. Therefore, CKD patients’ periodontal health needs to be screened for early dental interventions and monitored accordingly

Molecular epidemiology of piliated pneumococcal isolates at a major tertiary hospital in the Klang Valley, Malaysia

Objective: To characterise a collection of pili-carrying and none pili-carrying pneumococcal isolates of clinical origin for serotypes, antibiotic resistance and genotype. Methods: In total, 42 clinical isolates were collected between October 2017 and December 2019. Those isolates were analysed for antimicrobial susceptibility, serotype distribution, detection of pneumococcal virulence and pilus genes. Multilocus sequence typing was performed only for piliated isolates, followed by phylogenetic analysis. Results: The common isolation sites among the pneumococcal isolates were tracheal aspirate (28.6%), blood (26.2%), and sputum (23.8%). Fifty percent isolates were resistant to erythromycin, tetracycline (50.0%) and trimethoprim-sulfamethoxazole (43.0%). The most frequent were serotypes 19F (28.6%), 6A/B (23.8%) and 19A (14.3%). Piliated isolates were detected in a small proportion (33.3%); 64.3% were multidrug-resistant. ST320 was the prevalent sequence type among the piliated isolates and genetically related to the Pneumococcal Molecular Epidemiology Network clones Taiwan19F-14 (CC271). In the phylogenetic analysis, some piliated isolates showed a close association having similar ST320, carrying serotype 19A and both pilus genes indicating their clonal spread. Conclusions: Pneumococcal lineages of piliated isolates have been globally disseminated and pili could have played a role in the spread of antibiotic resistant clones