Dental Research Journal
Volume:7 Issue: 1, Jan 2010

Khat chewing is popular among Yemenis. This study was performed to investigate the effects of khat chewing on periodontal tissue and oral hygiene status. A total of 730 subjects (336 chewers and 394 non-chewers with a mean age of 31.5 ± 0.8 and 29.4 ± 0.9 years, respectively) were involved. Clinical data on periodontal tissues, oral hygiene status, gingival bleeding, burning sensation in the soft tissues, halitosis, ulcers in the oral cavity, difficulty in opening the mouth and swallowing solid food were collected to evaluate periodontal condition. Logistic regression analysis, student t test and chi-squared test were employed according to which hypotheses were being tested. The oral hygiene status of non-chewers was significantly better than that of chewers. The mean oral hygiene index of chewers was 2.12 ± 0.86 while that of non-chewers was 1.54 ± 1.12, the difference being statistically significant (P < 0.001). The incidence of gingival bleeding was significantly higher in khat-chewers. About 23% of chewers complained of difficulty in mouth-opening, as compared with only about 1% of non-chewers. Furthermore, 10% of chewers had difficulty in swallowing solid food. A burning sensation in the soft tissues was also found in a higher proportion of khat-chewers. Similarly, ulcers on the oral mucosa were present in about 7% of chewers, as compared to 0.5% of non-chewers. Gingival recession was present in about 51% and 26% of chewers and non-chewers, respectively. There does appear to be a relationship between the effect of chewing khat on periodontal tissue and oral hygiene status.

Internet is an important source of up-to-date dental information for delivering educational materials. The aim of this study was to determine the use of internet among dental students in Yazd. In this descriptive study, a questionnaire consisting of multiple choice questions was distributed to clinical undergraduate students studying at the School of Dentistry at the Shahid Sadoughi University of Yazd, Iran in 2009. The chi-square test was used to compare the frequency of internet use between the two genders. The level of statistical significance for all tests was set at 0.05. Seventy-nine percent of the students used the internet in various frequencies. In general, female students used the internet more often than their male counterparts (P < 0.0001). Although 13.79 percent of students used the internet to retrieve general information, dental topics were searched in the internet more frequently. The texts were the most commonly accessed materials (73.9 percent). Clinical photographs were accessed by 47.9 percent and radiographic and histopathologic materials by 12.3 and 10.9 percent of the students, respectively. Our students stated that they could find required information on dental subjects in English sites (96.6 percent) much more frequently than in the Farsi sites (78 percent). The results of this study reflect the attitudes of dental students to internet use as a part of their education in Shahid Sadoughi University of Yazd.

Human endeavors to prevent dental caries have led to the use of different modalities and agents, the most commonly used of which is fluoridated dentifrice. An in situ study was carried out to evaluate the efficacy of fluoridated dentifrices in achieving remineralization of initial caries-like lesions using surface microhardness measurements and to study the qualitative changes by scanning electron microscopy. Sixteen children 12-16 years of age wore a specially fabricated appliance with an artificially demineralized enamel slab for 24 hours a day, for four weeks. The children were divided into two groups, A and B. Following one week use of placebo dentifrice by both groups, group A used a fluoride dentifrice containing l000 ppm sodium monofluorophosphate, whereas group B used a placebo twice daily for 5 minutes for 21 days. Surface microhardness test carried out using a Knoop diamond indenter followed by scanning electron microscopy to evaluate the lesions. The results were statistically analyzed using the student t test. P value less than 0.05 was considered significant. The average hardness recovery for the experimental group was significantly higher than that in the control group (P < 0.001). Scanning electron microscopy revealed that fluoride significantly enhances remineralization of initial caries-like lesions. Regular use of fluoridated dentifrices significantly enhances remineralization of white spot lesions.

Denture stomatitis is a common oral lesion following the use of ill-fitting dentures. A layer of tissue conditioner is usually used to improve adaptation of the denture. These liners can support the in vivo adhesion and colonization of the oral Candida. The aim of this study was to evaluate the efficacy of the two common antifungal agents mixed with tissue conditioner against Candida albicans. Tissue conditioner disks (Acrosoft) with 5mm diameter and 1mm thickness containing different concentrations of nystatin and fluconazole (1%, 3%, 5%, 10% wt/wt) as well as disks with no antifungal agents (8 disks for each group) were prepared for experimental biofilm formation by inoculation with Candida albicans cell suspensions. The specimens were incubated in cell culture microtiter plate wells containing Sabouraud's broth in a rotator shaker at 30°C for 48 hours. Then, the specimens were rinsed and sonicated in sterile water to remove surface organisms. The attached yeasts were enumerated by inoculation of the yeast suspension on Sabouraud's agar. The data was compared using Kruskal-Wallis and Dunn’s tests using prism software. P value less than 0.05 was considered significant. The 1% to 10% mixture of nystatin and tissue conditioner completely inhibited the attachment and colonization of Candida albicans, although for fluconazole only a 10% concentration caused complete inhibition. Nystatin showed a potentially higher effect in inhibition of candida attachment and colonization (P = 0.0001) compared to that of fluconazole and a statistically significant difference was seen between 5% and 1% fluconazole (P = 0.0001). Tissue conditioner with 1% to 10% nystatin or 10% fluconazole can completely inhibit the adhesion and colonization of Candida albicans.

The use of electric current during application of etch-and-rinse adhesive systems has been recently introduced to decrease microleakage. This study investigated the effects of an electric field produced by an experimental device for the application of a two-step etch-and-rinse adhesive on moist dentin surface. Sixty freshly extracted human premolars were used for this study. In order to simulate real conditions, the pulpal pressure was set to 35 cm H2O for all the specimens. The teeth were divided into two groups: in group I, etch-and-rinse system (Single Bond) was applied with electric current while group II, etch-and-rinse system (Single Bond) was applied without electric current. Specimens were prepared for dye penetration test. The data were analyzed using Mann-Whitney U test. The results showed that group I had less microleakage scores compared to group II (P = 0.047). Based on the result of this study, it could be concluded that using electric current for applying adhesive systems had a significant effect on reducing microleakage.

PerioGlasâ (PG) is an alloplastic material used for grafting periodontal osseous defects since 1995. In animal models, it has been proven that PG achieves histologically good repair of surgically created defects. In clinical trials, PG was effective as an adjunct to conventional surgery in the treatment of intrabony defects. Because the molecular events due to PG that are able to alter osteoblast activity to promote bone formation are poorly understood, we investigated the expression of osteoblastic related genes in mesenchymal stem cells exposed to PG. The expression levels of bone related genes like RUNX2, SP7, SPP1, COL1A1, COL3A1, BGLAP, ALPL, and FOSL1 and mesenchymal stem cells marker (CD105) were analyzed, using real time reverse transcription-polymerase chain reaction. Pearson's chi-square (χ2) test was used to detect markers with significant differences in gene expression. PG caused induction of osteoblast transcriptional factor (like RUNX2), bone related genes osteopontin (SPP1), osteocalcin (BGLAP) and alkaline phosphatase (ALPL). All had statistical significant P values (< 0.05). PG has a differentiation effect on mesenchymal stem cells derived from peripheral blood. The obtained results can be relevant to better understanding of the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.

When provisional restorations are worn for long term period, the adhesion of bacteria becomes a primary factor in the development of periodontal diseases. The aims of this study were to evaluate the surface roughness and bacterial adhesion of four different provisional fixed prosthodontic materials. Ten cylindrical specimens were prepared from bis-acrylic composites (PreVISION CB and Protemp 3 Garant), a light-polymerized composite (Revotek LC), and a polymethyl methacrylate-based (Dentalon) provisional fixed prosthodontic materials. Surface roughness was assessed by profilometry. The bacterial adhesion test was applied using Porphyromonas gingivalis (P. gingivalis) and spectrofluorometric method. Statistical analysis was performed using ANOVA and Dunnett t-tests. All tested materials were significantly rougher than glass (P < 0.05). Revotek LC had the greatest fluorescence intensity, PreVISION and Protemp 3 Garant had moderate values and all of them had significantly more bacterial adhesion compared to glass (P < 0.05). Dentalon had the lowest fluorescence intensity among the provisional fixed prosthodontic materials. The quantity of bacterial adhesion and surface roughness differed among the assessed provisional fixed prosthodontic materials. The light-polymerized provisional material Revotek LC had rougher surface and more bacterial adhesion compared with the others.

Lipoma is a common tumor of soft tissue. Its location on the oral mucosa is rare, representing 1% to 5% of benign oral tumors although it is the most mesenchymal tumor of the trunk and proximal portions of extremities. Lipoma of the oral cavity may occur in any region. The buccal mucosa, tongue, and floor of the mouth are among the common locations. The clinical presentation is typically as an asymptomatic yellowish mass. The overlying epithelium is intact, and superficial blood vessels are usually evident over the tumor. Other benign connective tissue lesions such as granular cell tumor, neurofibroma, traumatic fibroma and salivary gland lesions (mucocele and mixed tumor) might be included in differential diagnosis. We present two cases of oral lipoma in unusual locations: one in junction of soft and hard palate and the other in tongue. Both were rare in the literature.