Polymicrobial oral biofilm models: simplifying the complex

Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host–pathogen interactions. In vivo animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained in vitro offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology

Bacterial Profiles of Subgingival Plaques in Periodontitis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142259/1/jper0447.pd

Microcapsules on Streptococcus mutans Serotypes by Electron Microscopy

Extracellular microcapsules have been demonstrated on cells of most serotypes of Streptococcus mutans by electron microscopy, using bacterial strains of the various serotypes and peroxidase labeled or unlabeled immune serum. A correlation was noted between the amount of capsular substance on the strains of S mutans examined and degree of antigenicity as expressed by the indirect fluorescent antibody (FA) title. A serotype d strain was shown to lose both antigenicity as determined by the FA reaction and capsular material as seen by electron microscopy with repeated in vitro passage. When 10% unheated rabbit serum was added to the medium, antigenicity and capsular material were restored.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68107/2/10.1177_00220345770560021101.pd

The benzoylarginine peptidase from Treponema denticola (strain ASLM), a human oral spirochaete: evidence for active-site carboxyl groups

The benzoylarginine peptidase of Treponema denticola (strain ASLM; a human oral spirochaete) was progressively and irreversibly inactivated by 1-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline, a carboxyl-group reagent. At acidic pH values, reaction of one mole of the modifier per active site of the enzyme resulted in total inactivation of the enzyme. Assuming that this modifier is a specific carboxyl reagent, the data suggest that the inactivation of the T. denticola benzoylarginine peptidase was caused by the modification of one carboxyl group located close to the active site of the enzyme. Results obtained with Woodward's reagent K ( N -ethyl-5-phenylisoxazolium 3’-sulphonate) supported these findings. Carbethoxylation with diethylpyrocarbonate effectively inactivated the enzyme, and addition of hydroxylamine at pH 7.0 restored the activity almost totally, suggesting that the pyrocarbonate had reacted with tyrosyl or histidyl residues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73886/1/j.1365-2958.1990.tb00721.x.pd

Metronidazole in Periodontitis: I. Clinical and Bacteriological Results after 15 to 30 Weeks

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141752/1/jper0325.pd

Identification of Streptococcus mutans serotypes in dental plaque by fluorescent antibody techniques

The presence of Streptococcus mutans in dental plaque may be related to human dental caries. The cultural identification of this organism in plaque is not likely to be used routinely in a clinical or epidemiological situation. In an effort to develop a simpler diagnostic means of identifying Strep. mutans in plaque, antisera were prepared for the 5 known serotypes of Strep. mutans. These immune sera were conjugated with fluorescein isothiocyanate, fractionated to obtain the gamma globulin and titrated against their homologous antigens to obtain working titres. These antisera were compared with cultural methods for their ability to detect Strep. mutans in plaque samples. Nonspecific fluorescent antibody reactions and weak cross-reactions were essentially eliminated by applying eriochrome black as a counterstain, after plaque and conjugated antiserum had been incubated. The results suggest that the fluorescent antibody is more sensitive than cultural methods in the detection of Strep. mutans in dental plaque.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33874/1/0000135.pd

Effects of dental probing on occlusal surfaces - A scanning electron microscopy evaluation

The aim of this clinical-morphological study was to investigate the effects of dental probing on occlusal surfaces by scanning electron microscopy (SEM). Twenty sound occlusal surfaces of third molars and 20 teeth with initial carious lesions of 17- to 26-year-old patients (n = 18) were involved. Ten molars of each group were probed with a sharp dental probe (No. 23) before extraction; the other molars served as negative controls. After extraction of the teeth, the crowns were separated and prepared for the SEM study. Probing-related surface defects, enlargements and break-offs of occlusal pits and fissures were observed on all occlusal surfaces with initial carious lesions and on 2 sound surfaces, respectively. No traumatic defects whatsoever were visible on unprobed occlusal surfaces. This investigation confirms findings of light-microscopic studies that using a sharp dental probe for occlusal caries detection causes enamel defects. Therefore, dental probing should be considered as an inappropriate procedure and should be replaced by a meticulous visual inspection. Critical views of tactile caries detection methods with a sharp dental probe as a diagnostic tool seem to be inevitable in undergraduate and postgraduate dental education programmes. Copyright (c) 2007 S. Karger AG, Basel

Adsorption of Streptococcus mutans on Chemically Treated Hydroxyapatite

Adsorption of Streptococcus mutans on hydroxyapatite and chemically treated hydroxyapatite was studied. Zeta potentials of the surfaces were measured. Chemically treated hydroxyapatite gave higher ζ potentials and lower S mutans adsorption.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67845/2/10.1177_00220345780570091601.pd

Anti-IL-17A blockade did not significantly reduce inflammatory lesions in a placebo-controlled pilot study in adult patients with moderate to severe acne

BACKGROUND\nMETHODS\nRESULTS\nCONCLUSIONS\nCJM112 is a potent anti-IL-17A monoclonal antibody, whose clinical efficacy in psoriasis was recently documented. This study aimed to assess the effect of IL-17A blockade, using CJM112, in patients with moderate to severe acne.\nA randomized, placebo-controlled, double-blind, parallel-group, proof-of-concept study was conducted on patients with moderate to severe acne. Patients received CJM112 300 mg, 75 mg, or placebo subcutaneously during Treatment Period1 (0-12 weeks). Patients receiving placebo were re-randomized to receive CJM112 300 mg or 75 mg during Treatment Period 2 (12-24 weeks). The primary endpoint was the number of inflammatory facial lesions at Week 12.\nAs the futility criterion was met during the interim analysis, only 52/75 (69.3%) patients were recruited. In total, 48/52 (92.3%) and 26/41 (63.4%) completed Treatment Periods 1 and 2, respectively. All groups exhibited a reduction in facial inflammatory lesions, with no difference observed between CJM112 and placebo (CJM112 300 mg 27.6 ± 20.7; CJM112 75 mg 30.4 ± 34.8; placebo 23.6 ± 13.6; primary endpoint). Additionally, no differences were observed between groups in other secondary and exploratory endpoints at Week 12.\nAnti-IL-17A therapy was not significantly different compared to the placebo in reducing inflammatory lesions in patients with moderate to severe acne.Pharmacolog