Clinical Outcomes of Lithium Disilicate Single Crowns after a Mean Duration of 3 Years - A Retrospective Study.

PURPOSE: To investigate the clinical performance and clinical survival rate of lithium disilicate-based core ceramic (IPS e.max Press) utilised in single crowns and to the accompanying periodontal health status. MATERIALS AND METHODS: A total of 47 patients with 88 IPS e.max Press single crowns were examined at the Faculty of Dentistry, University of Malaya, using modified United States Public Health Service evaluation criteria (USPHS). These 88 crowned teeth included 19 vital and 69 nonvital teeth that were restored with different post and core materials. The periodontal status was compared using the plaque index (PI), gingival recession (GR), modified papillary bleeding index (MPBI) and probing pocket depth (PPD) between the crowned teeth and contralateral control (sound) teeth. RESULTS: About 96.6% of the crowns exhibited satisfactory clinical performance. The mean survival rate at three years was 97.7%, and 100% at two years with a low incidence of fractures. There were no staitistically significant differences in the mean gingival recession (p = 0.182) and mean plaque scores (p = 0.102) between crowned and control teeth. The crowned teeth had higher mean MPBI (p = 0.000) and PPD (p = 0.051) compared to the contralateral sound teeth. Periodontal response in relation to subgingival crown margins, was statistically significantly lower regarding pocket depths (p = 0.01) and bleeding on probing (p = 0.00). CONCLUSION: IPS e.max Press crowns exhibited satisfactory clinical performance with high survival rate. No dentinal sensitivity was recorded. Plaque retention and gingival recession were similar to contralateral control teeth. Poor periodontal health was related to the subgingival crown margins.

Clinical Outcomes and Predictors of Satisfaction in Patients with Improved Lithium Disilicate All-Ceramic Crowns.

OBJECTIVES: The aim of this study was to determine the clinical outcomes and predictors of satisfaction in patients with lithium disilicate (LD) ceramic crowns. SUBJECTS AND METHODS: Clinical outcomes were assessed in 47 patients with 88 LD crowns using modified United States Public Health Service (USPHS) evaluation criteria and survival rates. The questionnaire for predictors included 3 aspects: (a) sociodemographic characteristics, (b) oral health habits (tooth brushing frequency, flossing frequency, and dental visits), and (c) satisfaction of the restorations (aesthetics, function, fit, cleansability, and chewing ability of the crowns, and overall satisfaction). Frequency distributions were computed using univariate and multivariate analysis. The Student t test and analysis of variance (ANOVA) were used to compare means across variables. Correlation analysis was done to assess the association between continuous variables. RESULTS: The age of crowns was 34.7 ± 9.7 months. The survival rate was 96.6% at 35.9 ± 9.2 months. There was a significant association between successful crown function and oral hygiene measures: tooth brushing (p˂ 0.001), dental visits (p = 0.006), and flossing (p = 0.009). A strong negative correlation was observed between aesthetic satisfaction (r = -0.717, p˂ 0.001) and chewing ability (r = -0.639, p˂ 0.001) with crown age. The linear regression model was significant for all predictors (p < 0.05) except overall satisfaction (p > 0.05). CONCLUSION: The LD crowns had long survival rates of 96.6% up to 35.9 ± 9.2 months and provided satisfactory clinical performance (low risk of failure). Oral hygiene habits such as brushing, flossing, and regular dental visits influenced patient satisfaction with LD crowns.

Impact of mandibular implant prostheses on the oral health-related quality of life in partially and completely edentulous patients.

OBJECTIVE: To assess the oral health-related quality of life (OHRQoL) of patients provided with mandibular implant fixed partial prostheses (IFPP) for rehabilitation of two adjacent missing posterior teeth and complete denture patients provided with mandibular implant-supported overdenture (ISOD). The response to change in OHRQoL with implant prostheses was additionally compared. MATERIAL AND METHODS: In this prospective study, 20 IFPP (mean age 47.0; SD 12.9 years) and 28 ISOD (mean age 61.5; SD 9.1 years) patients received 2 mandibular implants. Metal ceramic nonsplinted fixed prostheses were provided in IFPP group, while in ISOD group, the mandibular overdentures were retained by nonsplinted attachments. Patients rated their oral health-related quality of life using OHIP-14 Malaysian version at baseline (T0), 2-3 months (T1) and 1 year (T2) postimplant treatment. Mean OHIP-14 for total and domain scores between groups and intervals was analysed using repeated-measures ANOVA and t-test. Mann-Whitney and Wilcoxon signed-rank tests were used for the comparison of mean score change and effect size, while the association between pre- and post-treatment scores was determined using multivariate linear regression modelling. RESULTS: The total OHIP and domain scores before implant treatment were significantly higher (lower OHRQoL) in IFPP than in ISOD groups, except for physical pain where this domain showed similar impact in both groups. Postimplant scores between groups at T1 and T2 showed no significant difference. The mean score changes at T0-T1 and T0-T2 for total OHIP-14 and domains were significantly greater in IFPP except in the domains of physical pain and disability which showed no difference. Large effect size (ES) was observed for total OHIP-14 in IFPP while moderate in ISOD. Improved OHRQoL was dependent on the treatment group and pretreatment score. CONCLUSION: Improvement in OHRQoL occurred following both mandibular implant-supported overdentures and implant fixed partial prostheses.

Effect of nonsurgical periodontal therapy verses oral hygiene instructions on type 2 diabetes subjects with chronic periodontitis: a randomised clinical trial.

BACKGROUND: 40 subjects with type 2 diabetes and moderate to severe CP were randomly distributed to groups receiving either NSPT or OHI. Periodontal parameters, glycosylated haemoglobin (HbA1c) and high-sensitivity C-reactive protein (hs-CRP) were evaluated at baseline, 2- and 3-months intervals. METHODS: 40 subjects with type 2 diabetes and moderate to severe CP were randomly distributed to groups receiving either NSPT or OHI. Periodontal parameters, glycosylated haemoglobin (HbA1c) and high-sensitivity C-reactive protein (hs-CRP) were evaluated at baseline, 2- and 3-months intervals. RESULTS: 15 subjects from NSPT group and 17 from OHI group completed the study. The difference in plaque index (PI) between NSPT and OHI groups were significant at 2 months recall (p = 0.013). There was no significant difference between NSPT and OHI group for all other clinical periodontal parameters, HbA1c and CRP levels. At 3 months post-therapy, periodontal parameters improved significantly in both groups with sites with probing pocket depth (PPD) < 4 mm reported as 98 ± 1.8% in NSPT group and 92 ± 14.9% in OHI group. Mean PPD and mean probing attachment loss (PAL) within the NSPT group reduced significantly from baseline (2.56 ± 0.57 mm, 3.35 ± 0.83 mm) to final visit (1.94 ± 0.26 mm, 2.92 ± 0.72 mm) (p = 0.003, p < 0.001). For OHI group, improvements in mean PPD and mean PAL were also seen from baseline (2.29 ± 0.69 mm, 2.79 ± 0.96 mm) to final visit (2.09 ± 0.72 mm, 2.62 ± 0.97 mm) (p < 0.001 for both). Similarly, HbA1c levels decreased in both groups with NSPT group recording statistically significant reduction (p = 0.038). Participants who demonstrated ≥ 50% reduction in PPD showed significant reductions of HbA1c and hs-CRP levels (p = 0.004 and p = 0.012). CONCLUSION: NSPT significantly reduced PI at 2 months post-therapy as compared to OHI. Both NSPT and OHI demonstrated improvements in other clinical parameters as well as HbA1c and CRP levels. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01951547.

Oral Candida carriage and species prevalence amongst habitual gutka-chewers and non-chewers.

Oral Candida colonisation is higher in tobacco smokers as compared to non-smokers; however, it remains unknown whether smokeless tobacco chewers are susceptible to increased oral Candida colonisation. The aim was to determine the oral Candida carriage and species prevalence amongst habitual gutka-chewers and non-chewers in a cohort from Karachi, Pakistan. Forty-five gutka-chewers and 45 non-chewers were included. Information regarding age, sex, duration of gutka-chewing habit, daily frequency of gutka consumption, duration of holding gutka in the mouth, daily frequency of tooth-brushing and tongue brushing was collected using a questionnaire. Oral yeast samples were collected by scraping the dorsum of the tongue and bilateral buccal mucosa with a sterile cotton swab. Identification of yeast species was performed using standard techniques. Tongue lesions were identified and recorded. Unstimulated whole salivary flow rate (UWSFR) was also measured. There was no significant difference in the mean age, UWSFR and oral Candida carriage among gutka-chewers and non-chewers. Individuals were chewing gutka since 4·4 years and were consuming five gutka sachets daily. Candida albicans (C. albicans) was the most common yeast species isolated from 57·8% gutka-chewers and 64.4% non-chewers. In 24.4% gutka-chewers and 22·2% non-chewers, two candidal strains (C. albicans and Candida tropicalis) were isolated. In conclusion, the present results indicated no significant difference in oral Candida carriage in habitual gutka-chewers and non-chewers.

Dimensional profile of oral mucosa around combined tooth-implant-supported bridgework in macaque mandible.

PURPOSE: A stable oral mucosa is crucial for long-term survival and biofunctionality of implants. Most of this evidence is derived from clinical and animal studies based solely on implant-supported prosthesis. Much less is known about the dimensions and relationships of this soft tissue complex investing tooth-implant-supported bridgework (TISB). The aim here was to obtain experimental evidence on the dimensional characteristics of oral mucosa around TISB with two different abutment designs. METHODS: Sixteen 3-unit TISB were constructed bilaterally in the mandible of eight adult Macaca fascicularis. An implant system with a standard progressive thread design was the bone-anchoring implant in the second mandibular molar region while the second mandibular premolar served as the natural tooth abutment. Eight implants were connected with the tapered abutment, the remaining with butt-joint abutment, in a split-mouth design. These were allowed to functional load for 6 months before sacrification for histomorphometry. Six soft tissue indices were scored: coronal gingival mucosa-to-implant top distance (DIM); sulcus depth (SD); junctional epithelium (JE); connective tissue contact (CTC); implant top to first bone-to-implant contact distance (DIB); and biologic width (BW=SD+JE+CTC); corresponding parameters in the natural tooth abutment were also measured. RESULTS: Mucosal dimensions in tapered implants (*BW=3.33±0.43; SD=1.03±0.24; JE=1.08±0.13; CTC=1.22±0.23 mm) were comparable with those of natural tooth abutments (BW=3.04±0.18; SD=0.93±0.1; JE=0.78±0.1; Attachment=1.33±0.09 mm), but differed from butt-joint implants (*BW=4.88±1.24; SD=1.47±0.38; JE=1.49±0.4; CTC=1.92±0.93 mm) (*P<0.05). CONCLUSIONS: Results suggested that soft tissue dimensions around TISB are influenced by the implant-abutment interface and abutment material used. Mucosa investing tapered abutment tends to recapitulate soft tissue physiologic dimensions of natural tooth.

Salivary proteins associated with periodontitis in patients with Type 2 diabetes mellitus.

The objective of this study was to investigate the salivary proteins that are associated with periodontitis in patients with Type 2 diabetes mellitus (T2DM). Volunteers for the study were patients from the Diabetic Unit, University of Malaya Medical Centre, whose periodontal status was determined. The diabetic volunteers were divided into two groups, i.e., patients with periodontitis and those who were periodontally healthy. Saliva samples were collected and treated with 10% TCA/acetone/20 mM DTT to precipitate the proteins, which were then separated using two-dimensional polyacrylamide gel electrophoresis. Gel images were scanned using the GS-800(TM) Calibrated Densitometer. The protein spots were analyzed and expressed in percentage volumes. The percentage volume of each protein spot was subjected to Mann-Whitney statistical analysis using SPSS software and false discovery rate correction. When the expression of the salivary proteins was compared between the T2DM patients with periodontitis with those who were periodontally healthy, seven proteins, including polymeric immunoglobulin receptor, plastin-2, actin related protein 3, leukocyte elastase inhibitor, carbonic anhydrases 6, immunoglobulin J and interleukin-1 receptor antagonist, were found to be differentially expressed (p < 0.01304). This implies that the proteins may have the potential to be used as biomarkers for the prediction of T2DM patients who may be prone to periodontitis.

Evaluation of the isosceles-configured SUN TeethTMtoothbrush in dental plaque removal and gingival health.

Objective: To evaluate the clinical efficacy and safety profile of a novel-designed isosceles-configured (SUN Teeth™) toothbrush in comparison to a standard reference toothbrush with end-rounded bristles (approved by the American Dental Association [ADA]). Methods: The sample size was determined using the G-Power-software, version 3.1.2 and, accordingly, 104 subjects (ages 19 years to 25 years) were recruited and randomized into either the test group (n = 54) or the control group (n = 50). Prior to study commencement, scaling was performed followed by abstinence from oral hygiene for 24 hours. Baseline pre-brushing gingivitis scores (Lobene) and plaque scores (Turesky modification of Quigley Hein) were recorded. Brushing was performed for 3 minutes and post-brushing scores were recorded on days 1, 14, and 28 without refraining from regular brushing. Data were analysed with Statistical Package for Social Sciences (IBM-SPSS, v.25.0). Results: Post-brushing plaque scores showed significant reduction in both groups at all time intervals. However, no significant differences between the test and control brush groups were achieved at any time points. Conclusion: The isosceles-configured SUN TeethTMtoothbrush is equivalent in plaque removal to the conventional flat-bristled ADA reference brush.

Objectif: Évaluer l'efficacité clinique et le profil de sécurité d'une brosse à dents à conception novatrice d'une configuration isocèle (SUN TeethMD) en comparaison à une brosse à dents à référence standard dotée de soies aux pointes arrondies (approuvée par l'Association dentaire américaine [ADA]). Méthodologie: La taille de l'échantillon a été établie à l'aide du logiciel G-Power, version 3.1.2, et 104 sujets (âgés de 19 à 25 ans) ont été recrutés et randomisés dans un groupe d'essai (n = 54) ou un groupe témoin (n = 50). Avant le début de l'étude, un détartrage a été effectué, suivi par l'abstinence de l'hygiène buccodentaire pendant 24 heures. Des cotes de référence de gingivite prébrossage (Lobene) et des cotes de plaque (modification Turesky de Quigley Hein) ont été consignées. Le brossage était effectué pendant 3 minutes et les cotes après-brossage étaient consignées aux jours 1, 14 et 28 sans éviter le brossage régulier. Les données ont été analysées avec l'Ensemble des programmes statistiques relatif aux sciences sociales (IBM-SPSS, v.25.0). Résultats: Les cotes de plaque après-brossage ont été significativement réduites dans chaque groupe à tous les intervalles de temps. Cependant, aucune différence significative n'a été réalisée en aucun temps entre les groupes de brossage d'essai et témoin. Conclusion: La brosse à dents SUN TeethMDà configuration isocèle est équivalente en matière d'enlèvement de la plaque à la brosse de référence conventionnelle à soies plates de l'ADA.

Influence of abutment design on clinical status of peri-implant tissues.

OBJECTIVE: To compare the clinical soft tissue responses around implant tooth-supported 3-unit bridges using tapered abutments with those using butt-joint abutments. METHODS: In a split-mouth design study, 8 mm Ankylos (Dentsply Friadent, Germany) implants were placed in the second mandibular molar region of 8 adult Macaca fascicularis monkeys about 1 month after extraction of all mandibular molars. After 3 months of submerged healing, 3-unit metal bridges were constructed. Clinical data was collected by the author who was blind to the abutment selections. Implants were clinically evaluated using Waite plaque index, sulcus bleeding index, probing pocket depth (PPD), probing attachment loss (PAL), and width of keratinized mucosa at baseline (BL) and 3-month and 6-month intervals. Stability of the implant was assessed using Periotest device at BL and after 6 months. RESULTS: At BL, all the clinical variables did not differ statistically between the tapered and the butt-joint groups except for PPD (P < 0.05), where the mean PPD was greater in the butt-joint group (2.75 ± 1.02 mm) as compared with the tapered group (1.97 ± 0.65 mm). At the 3-month assessment, there was no difference in all clinical variables. After 6-month loading, no significant difference between these 2 groups was detected in all these variables, with the exception of PAL (P = 0.05) where mean PAL was greater for implants with the butt-joint abutments (0.91 ± 0.86 mm) in comparison with the tapered abutments (0.50 ± 0.88 mm), and mean Periotest values (PTVs) that indicate the tapered-abutment implants (PTV = -4.5 ± 1.60) were more stable than butt-joint-abutment implants (PTV = -1.5 ± 3.59) with P < 0.05. CONCLUSIONS: The differences in these mucogingival responses between these 2 groups at BL (during seating of abutments, especially of butt-joint abutments) and after 6-month loading indicated enhanced peri-implant soft tissue stability around the tapered abutments of this system. There was also enhanced-PTV in the test group for clinical mobility assessment after 6-month loading.

Structural studies of the O-antigenic polysaccharides from the enteroaggregative Escherichia coli strain 87/D2 and international type strains from E. coli O128.

The O-antigen of the lipopolysaccharide (LPS) from the enteroaggregative Escherichia coli strain 87/D2 has been determined by component analysis together with NMR spectroscopy. The polysaccharide has pentasaccharide repeating units in which all the residues have the galacto-configuration. The repeating unit of the O-antigen, elucidated using the O-deacylated LPS, is branched with the following structure: Analysis of the 1H NMR spectrum of the LPS revealed O-acetyl groups (approximately 0.7 per repeating unit) distributed over two positions. Subsequent analysis showed that the galactose residue carries acetyl groups at either O-3 or O-4 in a ratio of approximately 2:1. The international reference strain from E. coli O128ab was investigated and the repeating unit of the O-antigens has the following structure: Analysis of the 1H NMR spectrum of the LPS revealed O-acetyl groups (approximately one per repeating unit) distributed over two positions. The integrals of the resonances for the O-acetyl groups indicated similarities between the O-antigen from E. coli O128ab and that of E. coli strain 87/D2, whereas the O-acetyl substitution pattern in the E. coli O128ac O-antigen differed slightly. Enzyme immunoassay using specific anti-E. coli O128ab and anti-E. coli O128ac rabbit sera confirmed the results.

3D TECA hydrogel reduces cellular senescence and enhances fibroblasts migration in wound healing.

This study was designed to investigate the effect of 3D TECA hydrogel on the inflammatory-induced senescence marker, and to assess the influence of the gel on the periodontal ligament fibroblasts (PDLFs) migration in wound healing in vitro. PDLFs were cultured with 20 ng/ml TNF-α to induce inflammation in the presence and absence of 50 µM 3D TECA gel for 14 d. The gel effect on the senescence maker secretory associated-ß-galactosidase (SA-ß-gal) activity was measured by a histochemical staining. Chromatin condensation and DNA synthesis of the cells were assessed by 4',6-diamidino-2-phenylindole and 5-ethynyl-2'-deoxyuridine fluorescent staining respectively. For evaluating fibroblasts migration, scratch wound healing assay and Pro-Plus Imaging software were used. The activity of senescence marker, SA-ß-gal, was positive in the samples with TNF-α-induced inflammation. SA-ß-gal percentage is suppressed (>65%, P < 0.05) in the treated cells with TECA gel as compared to the non-treated cells. Chromatin foci were obvious in the non-treated samples. DNA synthesis was markedly recognized by the fluorescent staining in the treated compared to non-treated cultures. Scratch wound test indicated that the cells migration rate was significantly higher (14.9 µm2/h, P < 0.05) in the treated versus (11 µm2/h) for control PDLFs. The new formula of 3D TECA suppresses the inflammatory-mediated cellular senescence and enhanced fibroblasts proliferation and migration. Therefore, 3D TECA may be used as an adjunct to accelerate repair and healing of periodontal tissues.

Tannerella forsythensis prtH genotype and association with periodontal status.

BACKGROUND: The prtH gene of Tannerella forsythensis encodes for a cysteine protease possessing virulent properties. Subgingival colonization by T. forsythensis with this genotype has been suggested to be a discriminator between periodontal health and disease. This study examined the prevalence of T. forsythensis prtH genotype in subgingival plaque and its association with periodontal disease progression and current disease status. METHODS: Subjects harboring T. forsythensis in their subgingival plaque were identified using real-time polymerase chain reaction (PCR). The presence or absence of the prtH genotype was assessed by conventional PCR. Probing depths and relative attachment levels were also assessed. RESULTS: The prtH genotype was detected in 13 of 56 (23.2%) subjects harboring T. forsythensis in their subgingival plaque. Periodontal disease progression was defined as two or more sites with > or = 2 mm attachment loss in the previous 2-year period; current disease was defined as four or more sites with probing depths > or = 4 mm. The odds of periodontal disease (progression and/or current disease) were 1.55 times greater in subjects harboring prtH genotype T. forsythensis than in subjects in whom prtH was not detected. The prtH genotype was associated with higher numbers of T. forsythensis. In subjects with high levels of T. forsythensis, prtH genotype was associated with an increased extent of periodontal disease 2 years subsequently. CONCLUSIONS: These results show that T. forsythensis prtH genotype is associated with high levels of T. forsythensis. However, further work is needed to determine whether it also is a useful marker of periodontal disease progression in T. forsythensis-infected subjects.

Structural determination of the O-antigenic polysaccharide from Escherichia coli O166.

The O-antigen of the lipopolysaccharide from Escherichia coli O166 has been determined by component analysis together with 1D and 2D NMR spectroscopy techniques. The polysaccharide has pentasaccharide repeating units consisting of D-glucose (1), D-galactose (2) and N-acetyl-D-galactosamine (2) with the following structure: [ STRUCTURE: SEE TEXT]. In the 1H NMR, spectrum resonances of low intensity were observed. Further analysis of these showed that they originate from the terminal part of the polysaccharide, thereby revealing that the repeating unit has a 3-substituted N-acetyl-D-galactosamine residue at its reducing end.

Comparison of nonsurgical periodontal therapy with oral hygiene instruction alone for chronic periodontitis.

We evaluated changes in clinical variables and microbiological profiles of periodontopathogens among 56 patients with moderate to severe CP who were randomly assigned to oral hygiene instruction (OHI; n = 28) or nonsurgical periodontal treatment (NSPT; n = 28). Periodontal variables were assessed and subgingival plaque samples were obtained from deep pockets (≥5 mm) at baseline and 3 months after treatment. Real-time polymerase chain reaction was used to quantify Actinobacillus actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, and Prevotella intermedia. All clinical variables significantly improved in both groups. Improvements in gingival bleeding index (GBI), probing pocket depth (PPD), and periodontal attachment loss (PAL) were significantly greater at 3 months after treatment in the NSPT group. At baseline, the prevalences of all pathogens were high. Significant reductions in microbial count were observed for A. actinomycetemcomitans and T. forsythia (P ≤ 0.05) in the NSPT group. None of the improvements in clinical variables was associated with changes in microbiological profiles. At 3 months after treatment, NSPT was associated with significantly greater improvements in GBI, PPD, and PAL as compared with OHI. A. actinomycetemcomitans and T. forsythia counts were significantly lower in the NSPT group.

Resistin as potential biomarker for chronic periodontitis: A systematic review and meta-analysis.

OBJECTIVES: To determine the serum and gingival crevicular fluid (GCF) levels of resistin between individuals with chronic periodontitis (CP) and those without CP, and to evaluate the role of resistin in CP. MATERIALS AND METHODS: The addressed focused question was "Is there a difference in the resistin levels between individuals with CP and those without CP?" four electronic databases: Medline, PubMed (National Institutes of Health, Bethesda), EMBASE, and Science direct databases from 1977 up to March 2016 for appropriate articles addressing the focused question. EMBASE and Medline were accessed using OVID interface which facilitated simultaneous search of text words, MeSH or Emtree. Unpublished studies (gray literature) were identified by searching the Open-GRAY database and references of the included studies (cross referencing) were performed to obtain new studies. In-vitro studies, animal studies, studies that reported levels of other cytokines but not resistin, letters to the editor and review papers were excluded. RESULTS: Ten studies were included. Nine studies compared resistin levels between CP and periodontally healthy (H) individuals and reported higher mean serum and GCF levels of resistin in CP patients than the H controls. Two studies showed comparable resistin levels from GCF and serum between diabetes mellitus with CP (DMCP) and CP groups. Three studies included obese subjects and showed comparable serum and GCF resistin levels between obese subjects with CP (OBCP) and CP subjects. CONCLUSIONS: CP patients were presented with elevated levels of GCF or serum resistin as compared with H individuals. Resistin modulates inflammation in chronic periodontal disease and may be used as surrogate measure to identify subjects at risk for periodontitis. Resistin levels in patients with CP and systemic inflammatory disorders such as diabetes, obesity, or rheumatoid arthritis was not significantly higher than the levels in patients with only CP.

Structural determination of the O-antigenic polysaccharide from the Shiga toxin-producing Escherichia coli O171.

The structure of the O-antigenic part of the lipopolysaccharide (LPS) obtained from the verotoxin-producing Escherichia coli O171 has been determined. (1)H and (13)C NMR spectroscopy techniques in combination with component analysis were used to elucidate the O-antigen structure of O-deacylated LPS. Subsequent NMR analysis of the native LPS revealed acetylation at O-7/O-9 of the sialic acid residue. The sequence of sugars was determined by inter-residue correlations in (1)H,(1)H-NOESY and (1)H,(13)C-heteronuclear multiple-bond correlation spectra. The O-antigen is composed of pentasaccharide repeating units with one equivalent of O-acetyl groups distributed over two positions: -->4)-alpha-Neu5Ac7,9Ac-(2-->6)-beta-D-Galp-(1-->6)-beta-DGlcp-->(1-->3)-beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1--> Based on biosynthetic considerations, this should also be the biological repeating unit.

Structural studies of the O-antigenic polysaccharides from the enteroaggregative Escherichia coli strain 522/C1 and the international type strain from Escherichia coli O 178.

The structure of the O-antigenic polysaccharide (PS) from the enteroaggregative Escherichia coli strain 522/C1 has been determined. Component analysis and (1)H and (13)C NMR spectroscopy techniques were used to elucidate the structure. Inter-residue correlations were determined by (1)H,(1)H-NOESY and (1)H,(13)C-heteronuclear multiple-bond correlation experiments. The PS is composed of pentasaccharide repeating units with the following structure: [ structure: see text]. Analysis of NMR data reveals that on average the PS consists of four repeating units and indicates that the biological repeating unit contains an N-acetylgalactosamine residue at its reducing end. Serotyping of the E. coli strain 522/C1 showed it to be E. coli O 178:H7. Determination of the structure of the O-antigen PS of the international type strain from E. coli O 178:H7 showed that the two polysaccharides have identical repeating units. In addition, this pentasaccharide repeating unit is identical to that of the capsular polysaccharide from E. coli O9:K 38, which also contains O-acetyl groups.

Efficacy of acellular dermal matrix and autogenous connective tissue grafts in the treatment of gingival recession defects among Asians.

INTRODUCTION: The aim of the present study was to assess the efficacy of acellular dermal matrix (ADM) and subepithelial connective tissue grafts (sCTG) in the treatment of Miller class I and II gingival recession (GR) defects. METHODS: Six patients with eight GR sites were randomly assigned to the test group (GR defects treated with ADM) and control group (GR defects treated with sCTG). Recession height (RH) and width, probing depth, keratinized gingiva, clinical attachment level, and full mouth plaque and bleeding scores were measured at baseline, 3 and 6 months. RESULTS: The differences in mean changes were insignificant between the two groups in all parameters. In both groups, improvements from baseline to 3 and 6 months were significant for mean RH reduction and clinical attachment gain. A significant increase in the mean keratinized gingiva width was observed in both groups at 3 and 6 months. CONCLUSION: ADM and sCTG yield similar outcomes when used in the treatment of GR defects.

Qat Chewing and Periodontal Pathogens in Health and Disease: Further Evidence for a Prebiotic-Like Effect.

AIM: Qat chewing has been reported to induce subgingival microbial shifts suggestive of prebiotic-like properties. The objective here was to assess the effect of qat chewing on a panel of classical and new putative periopathogens in health and periodontitis. MATERIALS AND METHODS: 40 qat chewers and 40 nonchewers, equally stratified by periodontal health status, were recruited. Taqman, real-time PCR was used to quantify total bacteria, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Parvimonas micra, Filifactor alocis, Synergistetes, and TM7s in pooled subgingival biofilm samples. Differences in microbial parameters between the study groups were analysed using ordinal regression. RESULTS: In health, the qat chewers harboured significantly lower relative counts of P. gingivalis, T. forsythia, Synergistetes, and TM7s after adjustment for multiple comparisons (P ≤ 0.007). At nominal significance level, they also carried lower counts of TM7s and P. micra (P ≤ 0.05). In periodontitis, the chewers had lower counts of all taxa; however, only T. denticola withstood correction for multiple comparisons (P ≤ 0.0063). CONCLUSIONS: Qat chewing is associated with lower proportions of periopathogens, particularly in subjects with healthy periodontium, which supports previous reports of its prebiotic-like properties. This potentially beneficial biological effect can be exploited by attempting to isolate the active fraction.