Some aspects of protease production by a strain of Streptococcus sanguis

Our previous studies indicated that Arginine (Arg) plays a key nutritional role in Streptococcus sanguis P4A7 and that this organism can grow on whole casein as the sole nitrogen source. Its protease activities were therefore studied after glucose-limited continuous culture in a chemically-defined medium with either free amino acids or casein as the nitrogen source. Both culture supernatant and cell-associated endopeptidase (EP) and exopeptidase (amino-AP and carboxy-CP) activities were determined. Growth rate (mu) had little effect on EP, 75% of which was consistently in culture supernatants; AP and CP both decreased as mu was increased and both were predominantly cell-associated. At high growth pH, EP was substantially increased while AP and CP activities were optimal at pH 7. The most striking nutritional effect occurred under nitrogen limitation (glucose excess) when EP and AP were greatly increased and CP greatly decreased. It was concluded that S. sanguis is well equipped to scavenge its environment for Arg under a wide range of growth conditions.     

Influence of the chemical structure of functional monomers on their adhesive performance

Functional monomers in adhesive systems can improve bonding by enhancing wetting and demineralization, and by chemical bonding to calcium. This study tested the hypothesis that small changes in the chemical structure of functional monomers may improve their bonding effectiveness. Three experimental phosphonate monomers (HAEPA, EAEPA, and MAEPA), with slightly different chemical structures, and 10-MDP (control) were evaluated. Adhesive performance was determined in terms of microtensile bond strength of 4 cements that differed only for the functional monomer. Based on the Adhesion-Decalcification concept, the chemical bonding potential was assessed by atomic absorption spectrophotometry of the dissolution rate of the calcium salt of the functional monomers. High bond strength of the adhesive cement corresponded to low dissolution rate of the calcium salt of the respective functional monomer. The latter is according to the Adhesion-Decalcification concept, suggestive of a high chemical bonding capacity. We conclude that the adhesive performance of an adhesive material depends on the chemical structure of the functional monomer.     

Oral features in Kabuki make-up Syndrome

AIM: Kabuki make-up Syndrome is so named because of the characteristic facies of the affected patient. The face is similar to a Kabuki actor's mask. The main aim of this report was to describe the oral features in Kabuki Syndrome, focusing on the tooth anomalies. PATIENTS AND METHODS: Five subjects with Kabuki Syndrome, identified by the Child Neuropsychiatric Clinic of the University of Sassari, Italy, were enrolled. Their medical records were reviewed and oral and dental examinations were completed. The diagnosis was based upon the typical pattern of malformations and dysmorphic features reviewed by Matsumoto and Niikawa. RESULTS: All patients showed typical characteristics of the Syndrome such as a long palpebral fissure, lower palpebral eversion, arched eyebrows, short nasal septum, prominent and large ears, fingertip pads, mental retardation, and paramedian elevation of the lower lip. CONCLUSION: Kabuki make-up Syndrome is of unknown origin but a genetic aetiopathogenesis has been proposed. It is extremely rare; in Japan, where it is most frequent, it affects 1:32000 newborns. The typical facies of the syndrome, combined with general medical and dental examinations, are very important for diagnosis confirmation.     

A new periapical index based on cone beam computed tomography

The purpose of this study was to evaluate a new periapical index based on cone beam computed tomography (CBCT) for identification of apical periodontitis (AP). The periapical index proposed in this study (CBCTPAI) was developed on the basis of criteria established from measurements corresponding to periapical radiolucency interpreted on CBCT scans. Radiolucent images suggestive of periapical lesions were measured by using the working tools of Planimp software on CBCT scans in 3 dimensions: buccopalatal, mesiodistal, and diagonal. The CBCTPAI was determined by the largest lesion extension. A 6-point (0-5) scoring system was used with 2 additional variables, expansion of cortical bone and destruction of cortical bone. A total of 1014 images (periapical radiographs and CBCT scans) originally taken from 596 patients were evaluated by 3 observers by using the CBCTPAI criteria. AP was identified in 39.5% and 60.9% of cases by radiography and CBCT, respectively (P < .01). The CBCTPAI offers an accurate diagnostic method for use with high-resolution images, which can reduce the incidence of false-negative diagnosis, minimize observer interference, and increase the reliability of epidemiologic studies, especially those referring to AP prevalence and severity.     

Biofilm on the apical region of roots in primary teeth with vital and necrotic pulps with or without radiographically evident apical pathosis

Aim  To evaluate, by scanning electron microscopy (SEM), the presence of biofilms on the external surfaces of the apical third of roots of human primary teeth with vital or necrotic pulps with and without radiographically evident periradicular pathosis.
Methodology  Eighteen teeth were selected: group I – normal pulp ( n  = 5), group II – pulp necrosis without radiographic evidence of periapical pathosis ( n  = 7) and group III – pulp necrosis with well-defined radiographic periapical pathosis ( n  = 6). After extraction, the teeth were washed with saline and immersed in 0.03 g mL⁻¹ trypsin solution for 20 min. The teeth were then washed in sodium cacodilate buffer and stored in receptacles containing modified Karnovsky solution. The teeth were sectioned, dehydrated in an ethanol series, critical-point dried with CO₂, sputter coated with gold and the external root surface in the apical third examined by SEM.
Results  In the teeth of groups I and II, the apical root surfaces were covered by collagen fibres, with no evidence of bacteria (100%). In the teeth of group III, the root apices had no collagen fibres but revealed resorptive areas containing microorganisms (cocci, bacilli, filaments and spirochetes) in all cases (100%).
Conclusion  Microorganisms organized as biofilms on the external root surface (extraradicular infection) were detected in primary teeth with pulp necrosis and radiographically visible periapical pathosis.     

Periodontal tissue engineering and regeneration: Consensus Report of the Sixth European Workshop on Periodontology

Aim: To review the scientific preclinical background and clinical studies of current methods of periodontal regeneration in the treatment of infrabony defects and soft tissue deficiencies
Method: Five commissioned review papers including two systematic reviews were scrutinized by a group of experts in order to derive consensus conclusions, clinical relevance/implications and to propose future research requirements.
Results: The following five papers were assessed:
  1. Biological mediators and periodontal regeneration: a review of enamel matrix proteins at the cellular and molecular levels.
  2. Regeneration of periodontal tissues: combination of barrier membranes and grafting materials – Biological foundation and preclinical evidence.
  3. Clinical outcomes with bioactive agents alone or in combination with grafting or GTR
  4. Treatment of gingival recession with coronally advanced flap procedures. A systematic review.
  5. Soft tissue management at implant sites     

Orthodontics and vertical distraction osteogenesis of the maxilla

A female patient (age 26) visited the orthodontist for correction of the reduced exposure of the upper incisors during laughing. She also reported crowding of the lower incisors and an association between lisping and her open bite. The diagnosis in this case: a Class III malocclusion case with incisor crowding and an open bite. Because her main complaint was reduced upper incisor exposure while talking and laughing, which would not be corrected with orthodontic appliances only, the position of the maxilla was corrected during orthodontic treatment by means of vertical intra-oral maxillary distraction. An acceptable and relatively stable result was achieved.     

Effect of root canal irrigants on cervical dentine permeability to hydrogen peroxide

Aim To examine the effects of various root canal irrigants on cervical dentine permeability by monitoring the diffusion of hydrogen peroxide (H₂O₂). Methodology Sixty cervical dentine discs were prepared from human third molar teeth. After removal of enamel and cementum, the outer dentine surface was etched with 17% ethylenediamine tetraacetic acid (EDTA) for 1 min. The dentine discs were randomly assigned to five groups according to the irrigant used: A, saline solution; B, 2.5% sodium hypochlorite solution (NaOCl); C, 5% NaOCl; D, 17% EDTA and 2.5% NaOCl; E, 17% EDTA and 5% NaOCl. After irrigation on the inner dentine surface with the various solutions, the diffusion of 30% H₂O₂ was evaluated through each disc using a plastic‐split chamber. H₂O₂ was applied to the inner‐side chamber, while the outer‐side chamber was filled with de‐ionised water. After 30 min of application of H₂O₂, the solution in the outer‐side chamber was collected to determine the concentration of H₂O₂ using a spectrophotometer. Results The penetration of H₂O₂ through dentine in group E was significantly highest, followed by groups D, C, B and A respectively (one‐way anova , P < 0.05). Conclusions Among the irrigants used, 17% EDTA and 5% NaOCl had the greatest effect in increasing dentinal permeability to H₂O₂.     

Epstein-Barr virus in lingual epithelium of liver transplant patients

Thirty-three liver transplant patients and 20 controls were examined for the presence of EBV in epithelium of the lateral border of the tongue by negative staining electron microscopy. Five of the specimens (15%) showed particles typical of the herpes virus family, while all controls were negative for EBV. In 3 of the 5 patients moderate oral hairy leukoplakia was observed clinically. Our results indicate that EBV may be expressed at the lateral border of the tongue of liver transplant patients, who in some cases show oral hairy leukoplakia clinically.     

Identification of plasmids in Actinobacillus actinomycetemcomitans and construction of intergeneric shuttle plasmids

A collection of 39 isolates of Actinobacillus actinomycetemcomitans , obtained from laboratories located in 5 different geographical regions of the United States, was examined for the presence of plasmid DNA. Only 2 of the strains examined, designated VT736 and VT745, harbored detectable plasmids. Strain VT736 contained a 1.9 kb plasmid species (pVT736-1) and a larger (>30 kb) species (pVT736-2). Both plasmids were detected in the covalently closed circular DNA fraction of dye buoyant density gradients. However, only the smaller plasmid was observed in agarose gels containing plasmid-enriched cell lysates prepared by a rapid screening procedure. Strain VT745 contained a single, 24 kb, plasmid (pVT745) that was observed consistently in plasmid-enriched lysates, as well as in the plasmid band of dye buoyant density gradients. A restriction endonuclease map of pVT736-l was constructed. The plasmid contained one site each for the enzymes Hinc II, Kpn I and Xho I, located 600 to 700 bp from each other on the pVT736-1 map. Hinc II-digested pVT736-1 DNA could not be cloned in Escherichia coli. However, intact pVT736-1 digested with Kpn I or Xho I could be cloned in E. coli on pUC19 or pGEM7Zf(-), respectively. Kpn I-digested pVT736-1 was cloned in both orientations on pUC19, but Xho I-digested pVT736-1 was clonable in only one orientation on pGEM7Zf(-). Each of the 3 types of chimeric plasmid constructs provided a potential A. actinomycetemcomitans/E. coli shuttle plasmid for the development of a genetic transfer system in A. actinomycetemcomitans.