Levels of evidence and journal impact factor in oral and maxillofacial surgery

The aim of this study was to identify the relationship between quality of research, in terms of levels of evidence, and journal impact factor (IF), and to describe the pattern of publications in oral and maxillofacial surgery. All four major journals in this subject area only, and with a published IF, were included in the study. Latest published IF dated 2004 was chosen, and all articles related to its calculation were accessed and classified into four levels of evidence. Correlation between levels of evidence and IF was investigated and the pattern of publications was described. All eligible 932 published articles were analysed. None (0%) were level I evidence, 20 (2%) were Level II, 70 (8%) level III and 337 (40%) level IV; 465 (50%) articles were classified as non-evidence. IF ranged from 0.689 to 1.154. There were statistically significant correlations between levels of evidence and IF (rho=1.0, P<0.01). Among the 465 non-evidence articles, there were 219 (47%) case reports, 91 (20%) animal studies, 52 (11%) laboratory studies, 35 (8%) technical notes, 24 (5%) tutorial articles, and 16 (3%) reviews articles.     

Bacterial community profiles of endodontic abscesses from Brazilian and USA subjects as compared by denaturing gradient gel electrophoresis analysis

This study compared the bacterial community profiles of the microbiota associated with acute apical abscesses from Brazilian and USA patients using denaturing gradient gel electrophoresis (DGGE). DNA was extracted from purulent exudate aspirates and part of the 16S rRNA gene was amplified by polymerase chain reaction and separated by DGGE. The resulting banding patterns, which were representative of the bacterial community structures in samples from the two locations, were then compared. Distinct DGGE banding patterns were observed from different samples. Ninety-nine bands with distinct positions in the gels were detected, of which 27 were found only in the USA samples and 13 were exclusive to Brazilian samples. Four of the 59 shared bands showed very discrepant findings with regard to prevalence in the two locations. Cluster analysis of DGGE banding profiles showed a great variability in the bacterial populations associated with teeth with abscesses regardless of the geographical location. Two big clusters, one for each location, were observed. Other clusters contained a mixture of samples from the two locations. The results of the present study demonstrated a great variability in the bacterial community profiles among samples. This indicates that the bacterial communities of abscesses are unique for each individual in terms of diversity. The composition of the microbiota in some samples showed a geography-related pattern. Furthermore, several bands were exclusive for each location and others were shared by the two locations and showed great differences in prevalence.     

Osseointegrated implants as an adjunct to facemask therapy: a case report

Branemark Implants were placed in the zygomatic buttresses of the maxilla in a 12-year and 1-month-old female patient with a Class III malocclusion caused by maxillary growth retardation secondary to repair of a unilateral cleft lip and palate defect. The implants were left to integrate for 6 months followed by placement of customized abutments that projected into the buccal sulcus. Elastic traction (400 g per side) was applied from a facemask to the implants at 30 degrees to the occlusal plane for 14 hours per day for 8 months (ages 12 years and 10 months to 13 years and 6 months). The maxilla moved downward and forward 4 mm rotating anteriorly as it was displaced. The change in the maxillary occlusal plane resulted in a secondary opening of the mandible. There was a 2 degrees increase in the SN-mandibular plane angle and an increase in nasion to menton distance of 9 mm. Clinically, this resulted in an increase in fullness of the infraorbital region and correction of the pretreatment mandibular prognathism. There was an increase in nasal prominence as the maxilla advanced. This contributed to the increase in facial convexity. The secondary dental change frequently seen in standard facemask therapy was avoided. The displacement of the maxilla was stable 1 year beyond cessation of facemask therapy. The patient's midface profile was improved by age of 13 years and 6 months. Details of the clinical procedure and treatment changes are presented.     

The clinical assessment of oral dryness is a significant predictor of salivary gland hypofunction

OBJECTIVES: To compare subjective complaints of xerostomia and salivary gland dysfunction and a clinical assessment of oral dryness with an objective measurement of salivary gland dysfunction, in a group of UK patients attending a Dry Mouth Clinic. The aim of the study was to identify signs and symptoms that may be of predictive value for salivary gland hypofunction (SGH) in clinical practice. METHODS: This prospective study investigated 214 patients who attended a Dry Mouth Clinic, held at Liverpool University Dental Hospital. Patients gave a history of xerostomia for a minimum of 6 months and were asked standardised questions to subjectively assess oral dysfunction. The oral mucosa was then clinically assessed for dryness and sialometry was performed. Unstimulated whole saliva flow rates (UFR) of < 0.2 ml min-1 were considered to be indicative of SGH. RESULTS: One or more symptoms of oral dysfunction were reported in 178 (83%) patients, in addition to xerostomia. The clinician diagnosed oral dryness in 105 patients. Objective evidence of SGH was found in 125 (58%) of patients. The clinicians' subjective assessment of oral dryness was indicative of a reduced UFR (P < 0.0001) and a significant predictor of an UFR < 0.2 ml min-1 using logistic regression analysis (odds ratio 9.6; 95% CI 4.8 and 19.3). The mean UFR of patients who reported symptoms of oral dysfunction was significantly lower than the mean UFR of patients who reported no oral dysfunction. Using logistic and multiple regression analyses, symptoms of oral dysfunction were not found to be significant predictors of either an UFR < 0.2 ml min-1 or a reduced UFR. CONCLUSIONS: The clinical assessment of oral dryness was a significant predictor of SGH, in this selected group of patients. Patients who complain of xerostomia may have additional symptoms of oral dysfunction indicative of a reduced UFR.     

The cariostatic potential of cheese: cooked cheese-containing meals increase plaque calcium concentration

OBJECTIVE: Eating cheese by itself increases plaque calcium concentration - which is probably one mechanism of the well-established action of cheese in reducing experimental caries. The objective of the present study was to determine whether consumption of cheese as part of a cooked, mixed meal (ie as it is habitually consumed) is able to increase plaque calcium concentration. DESIGN: Plaque samples were obtained from 16 adult volunteers before and 5 minutes after consumption of either a 15 g cube of cheese, one of two cheese-containing test meals, or one of two control meals. Each subject tested each of the four meals on a separate occasion. Plaque calcium concentration was measured using atomic absorption spectrophotometry. RESULTS: The test meals increased plaque calcium concentrations to a significantly greater magnitude than the control meals (P < 0.05). A non-significant trend was observed towards a larger magnitude of change in plaque calcium concentration in the 8 subjects with the lowest, compared with the 8 subjects with the highest baseline concentration. CONCLUSION: The findings suggest that cheese-containing meals increase plaque calcium concentration and thus probably protect against dental caries.     

Transposition of mesial and distal aspects of maxillary first molars: case report

Congenital absence of one or more teeth, hypodontia, is the most common developmental anomaly and is often accompanied by the presence of other tooth anomalies. In this case two Japanese sisters have several congenitally missing primary and permanent teeth and morphological abnormalities of maxillary first molars. One sister has transposition of mesial and distal aspects of a maxillary first molar, whose cusps display a normal shape. Another sister has maxillary first molars, which look like maxillary second molars. Mesio-distally shift of teeth is a very rare anomaly making this particular case important to analyze the teeth formation and development.     

Actinobacillus actinomycetemcomitans serotype e--biotypes, genetic diversity and distribution in relation to periodontal status

Actinobacillus actinomycetemcomitans isolates from 356 individuals were screened for identification of serotype e in order to investigate its distribution in relation to periodontal status. From subjects with serotype e, 1–6 isolates per subject ( n =61) were genotyped using arbitrarily primed–polymerase chain reaction (AP-PCR) and apaH gene polymerase chain reaction–restriction fragment-length polymorphism (PCR-RFLP) analysis to determine the genetic heterogeneity within the serotype. Furthermore, one serotype e strain per subject was tested for fermentation of 8 carbohydrates for biotyping. Among patients with adult periodontitis ( n =219), localized juvenile periodontitis ( n =55) and other forms of early-onset periodontitis ( n =18) serotypes b, a and c, respectively, were the most frequently detected serotypes. Non-periodontitis subjects ( n =64) were predominantly colonized with serotype c. Serotype e was found in 30 (14%) adult periodontitis patients, 2 (11%) early-onset periodontitis patients and in 5 (8%) non-periodontitis individuals, but in none of the 55 localized juvenile periodontitis patients. AP-PCR distinguished 3 and apaH gene PCR-RFLP analysis 2 genotypes among the 61 A. actinomycetemcomitans serotype e isolates, one genotype per subject. The AP-PCR genotypes 1 and 3 represented the apaH genotype 1 and the AP-PCR genotype 2 the apaH genotype 2. On the basis of variable fermentation of galactose and xylose, 3 biotypes among A. actinomycetemcomitans serotype e were established. Contrary to the absence of A. actinomycetemcomitans serotype e in localized juvenile periodontitis patients, its detection frequency was comparable among other forms of periodontitis and periodontal health. Clinical serotype e isolates form at least 2 genetic types and 3 biotypes.     

Expression of receptors for basic fibroblast growth factor on human periodontal ligament cells

Basic fibroblast growth factor (FGF-2; bFGF) is a major mitogen for connective tissue cells, and participates in the healing process. It has already been reported that FGF-2 could be applicable to enhance periodontal regeneration. In the present study, we examined FGF receptor (FGFR) expression on human periodontal ligament (PDL) cells. The binding of [¹²⁵I]-labeled FGF-2 to human PDL cells was studied by radioreceptor assay. The binding of [¹²⁵I]-FGF-2 to PDL cells reached a plateau after 2.5 h incubation at 4°C and was inhibited by the addition of unlabeled FGF-2 and acidic FGF (FGF-1; aFGF), but not insulin-like growth factor-I, platelet-derived growth factor and transforming growth factor-β₁. Scatchard analysis revealed the presence of approximately 1.0 × 10⁵ FGF-2 binding sites per cell with an apparent Kd of 1.2 × 10-¹⁰ M. Interestingly, the binding of [¹²⁵I]-FGF-2 on PDL cells reached its maximum at d 6 of the culture and then gradually decreased. Scatchard analysis also demonstrated that the number of FGFRs on a PDL cell was altered during the course of the culture, while the affinity between FGF-2 and its receptor was not. The responsiveness of PDL cells to FGF-2, which was monitored by the inhibitory effect on alkaline phosphatase activity, was reduced in proportion to the decrease in the number of FGFRs on the PDL cells. The present study suggests that PDL cells alter the responsiveness to FGF-2 during the course of the culture by changing the density of its receptor, and that the density of FGFR expression might be a marker of the cytodiflerentiation of PDL cells into mineralized tissue forming cells.     

Eugenol inhibits K+ currents in trigeminal ganglion neurons

Eugenol, a natural capsaicin congener, is widely used in dentistry. Eugenol inhibits voltage-activated Na(+) and Ca(2+) channels in a transient receptor potential vanilloid 1 (TRPV1)-independent manner. We hypothesized that eugenol also inhibits voltage-gated K(+) currents, and investigated this in rat trigeminal ganglion neurons and in a heterologous system using whole-cell patch clamping. Eugenol inhibited voltage-gated K(+) currents, and the inhibitory effects of eugenol were observed in both capsaicin-sensitive and capsaicin-insensitive neurons. Pre-treatment with capsazepine, a well-known antagonist of TRPV1, failed to block the inhibitory effects of eugenol on K(+) currents, suggesting no involvement of TRPV1. Eugenol inhibited human Kv1.5 currents stably expressed in Ltk(-) cells, where TRPV1 is not endogenously expressed. We conclude that eugenol inhibits voltage-gated K(+) currents in a TRPV1-independent manner. The inhibition of voltage-gated K(+) currents is likely to contribute to the irritable action of eugenol. Abbreviations: human Kv1.5 channel, hKv1.5; transient receptor potential vanilloid 1, TRPV1.