Initial effects of the tongue crib on tongue movements during deglutition: a Cine-Magnetic resonance imaging study

The objective of this study was to investigate the initial effects of a tongue crib on tongue movements during deglutition by using real time balanced turbo field echo (B-TFE) Cine-MR imaging. A total of 21 patients were evaluated in this study. The open-bite group (OBG) consisted of 11 patients (seven girls, four boys) who had a mean age of 11.09 +/- 2.02 years and a mean overbite of -5.14 +/- 1.83 mm. These patients were evaluated initially (T1) and while wearing a tongue crib (T2). A total of 10 patients (five girls, five boys) with a mean age of 14.5 +/- 2.6 years and with a mean overbite of 1.6 +/- 0.5 mm served as controls (CG), and only initial records were obtained from these patients. T2 was compared with T1 and CG. T1 was also compared with CG. We evaluated deglutition during three stages matching oral (1), pharyngeal (2), and esophageal (3) stages. Our results indicated that the tongue's tip positioned more posteriorly when the crib was in place (T2) compared with both T1 and CG; the anterior portion of the tongue's dorsum was at a lower position in T2 compared with both T1 and CG at stage 3; the midportion of the tongue's dorsum was at a lower position in T2 than in T1 and CG at stages 1 and 2. To compensate for the posterior position of the tongue's tip (caused by the tongue crib), adaptive changes occurred in the anterior and midportions of the dorsum of the tongue.     

Effect of five staining solutions on the colour stability of two acrylics and three composite resins based provisional restorations

The effect of coffee, tea, coca-cola, orange-juice and red wine on the colour stability of acrylic and composite based provisional materials were evaluated. Two acrylic resins and three composite resins were studied. 48 standardized specimens for each provisional material were prepared. Each group was divided into 6 subgroups. Specimens from each group were immersed in staining solutions at room temperature for 30 days. Red wine and tea caused the most significant colour changes and orange juice showed the least significant colour changes. deltaE of all of the provisional restorations materials was changed after the immersion in all of the staining solutions during the experimental process.     

Bactericidal effect of Er,Cr:YSGG laser on Streptococcus mutans

The aim of this study was to compare the antibacterial activities of Er,Cr:YSGG laser with two different power outputs against a chlorhexidine gluconate-based cavity disinfectant. A cavity tooth model test was used to determine the antibacterial activity. Four cylindrical cavities were prepared on the dentin surface of 10 bovine incisors and left in contact with Streptococcus mutans for 72 hours to allow bacterial invasion. Following which, Er,Cr:YSGG laser with 0.75 W and 1 W power outputs and a chlorhexidine gluconate-based cavity disinfectant were applied separately on one of the three infected cavities, whereas the fourth was left untreated for control. Standardized amounts of dentin chips were obtained from the cavity walls, and the number of bacteria recovered was counted. Statistical analysis was carried out using one-way ANOVA and Dunnett's C test (p=0.05). No significant differences were observed among the data obtained from the chlorhexidine gluconate-based cavity disinfectant and the two Er,Cr:YSGG laser groups (p>0.05). However, when compared to the control group, both Er,Cr:YSGG laser groups and the chlorhexidine gluconate-based cavity disinfectant resulted in significantly less bacterial recovery (p<0.05). In conclusion, the antibacterial activity on S. mutans demonstrated by Er,Cr:YSGG laser with both energy outputs was similar to that of the tested chlorhexidine gluconate-based cavity disinfectant.     

Analysis of in situ proliferative activity in oral gingival epithelium in patients with xerostomia

BACKGROUND: Sj?gren's syndrome is an autoimmune disease characterized by xerostomia and keratoconjunctivitis sicca. The relationship between xero-stomia and proliferative activity in human gingival epithelium is not known. Proliferating cell nuclear antigen (PCNA) is a nuclear protein associated with the cell cycle. Nuclear PCNA immunoreactivity is found in the proliferative compartment of normal tissues. The aims of this study were to evaluate PCNA expression in oral gingival epithelium of healthy and inflamed gingiva obtained from patients with Sj?gren's syndrome, and to compare the results to age- and gender-matched subjects with normal salivary function. METHODS: Eighteen Sj?gren's syndrome patients and 28 controls (14 with chronic periodontitis and 14 with no clinical evidence of periodontal disease) were included in the study. Biopsies were obtained from both inflamed and healthy gingiva. The expression of PCNA was evaluated in formalin-fixed, paraffin-embedded gingival samples using an immunoperoxidase technique and PC10 monoclonal antibody to PCNA. RESULTS: PCNA expression was observed both in the basal and suprabasal layers, and was found to be more prominent in the suprabasal layers. Proliferative index (PI) in inflamed gingiva was significantly lower in the Sj?gren's syndrome group. However, no significant difference was observed between the study and control groups with respect to PI in healthy gingiva. In both groups, PI was found to be increased due to inflammation. CONCLUSIONS: Our data indicate that proliferative activity is observed in the suprabasal layers and, less frequently, in the basal layer. Inflammation caused increased proliferative activity. However, this positive effect of inflammation on epithelial cell proliferation decreased significantly with a lack of saliva. Therefore, it appears that saliva-derived biological mediators may also contribute to increased proliferative activity observed during inflammation.     

Effects of repeated scaling and root planing and/or controlled oral hygiene on the periodontal attachment level and pocket depth in beagle dogs

This study was performed to evaluate the effect of initial and/or repeated subgingival scaling with or without controlled oral hygiene on the level of periodontal attachment and pocket depth in Beagle dogs. furthermore, the effect of repeated scaling on the progression of naturally developed periodontitis was to be determined. At baseline, and at 1,6,12,24 and 36 months clinical parameters for plaquen deposits (PII), calculus (CI), gingival health (GI) periodontal attachment from the cementoenamel junction (CEJ) and pocket depth were recorded by the same examiner. Eight healthy Beagles, 3 1/2–6 years of age with moderate naturally developed periodontal desease were divided into experimental and control animals. In the experimental group, 4 dogs received a thorough scaling and root planing at the start of the experiment. thereafter the experimental dogs were subjected to daily toothbrushing and a rubber cup and pumice prophylaxis every two weeks. The remaining 4 control dogs were not subjected to any oral hygience measures. Two quadrants diagonally opposed in each animal (experimentaal and control) were scaled and root planed every six months. In the experimental group a significant increase in attachment level was maintained throughout the study. Initial scaling followed by oral hygiene reduced pocket depth singificantly and pocket reduction was maintained over the three year period. Repeated scaling did not influence the mainternance of the attachment level or the reduction in pocket depth in the experimental group. The control animals continued to lose attachment and pocket depth increased during the study. Scaling every six months without oral hygience resulted in loss of attachment and increase in pocket depth, although the rate of attachment loss was retarded. It is concluded that following initial scaling conticuous removal of bacterial plaque is essential for the maintenance of periodontal attachment. In moderate periodontal disease the levels of attachments may be maintained without surgical therapy.     

The influence of different placement techniques on the microtensile bond strength of low-shrink silorane composite bonded to Class I cavities

The aim of this in vitro study was to evaluate the microtensile bond strength (μTBS) of a low-shrink silorane-based composite (Filtek Silorane) and a methacrylate-based composite (Filtek Z250) to the bottom dentin of a Class I cavity using different placement techniques. Twelve third molars were used. Standard, box-type Class I cavities (6.0 x 4.0 x 2.5 mm) were prepared at the occlusal crown center, with the pulpal floor ending approximately at the midcoronal dentin. The teeth were then randomly divided into four groups, according to each placement technique: ZI--Filtek Z250 placed incrementally; ZB--Filtek Z250 placed in bulk; SI--Filtek Silorane placed incrementally; and SB--Filtek Silorane placed in bulk. Each restored third molar was subjected to microtensile bond testing after 24 hours of storage in distilled water at 37 degrees C. After storage, each molar was longitudinally sectioned in both axes to obtain rectangular sticks with an approximate 0.49 mm2 cross-sectional area. Data were analyzed by one-way ANOVA followed by a Tukey post hoc test (P = 0.05). After debonding, the failure modes were analyzed using a stereomicroscope. The ZI group (72.6 MPa) showed the highest μTBS, followed by the ZB group (60.2 MPa), while the SI (34.4 MPa) and SB (42.6 MPa) groups demonstrated statistically significant lower bond strengths. The type of placement technique did not influence the μTBS of silorane-based composites to the bottom dentin of Class I cavities. The methacrylate-based composite showed superior performance, regardless of the placement technique.     

Carbohydrate components of the gingival exudate

This paper describes the presence and amounts of free glucose, hexosamine and hexuronic acid in the gingival exudate. Exudate was sampled on filterstrips from individuals with different degrees of gingival inflammation. The strips were weighed before and after absorption of exudate and the exudate was calculated. The exudate was extracted and the content of glucose, hexosamine and hexuronic acid was determined colorimetrically. In keeping with previous studies the amount of exudate increased with the severity of inflammation. Exudate glucose varied between 1.13 and 7.09 μg/mg exudate. The hexosamine content was approximately 0.6 μg/mg and the hexuronic acid concentration varied between 50 and 60 μg/mg. The possible sources of origin of the carbohydrate components are discussed.     

Dentoalveolar distraction osteogenesis for rapid orthodontic canine retraction.

PURPOSE: We present a technique to reduce the overall orthodontic treatment time by means of dentoalveolar distraction osteogenesis. PATIENTS AND METHODS: Eleven patients who were planned to undergo orthodontic treatment with bilateral first premolar extractions and subsequent bilateral canine tooth distalization underwent osteotomy around the canine tooth. The first premolar was extracted, and the buccal bone was carefully removed. After wound closure, a special orthopedic device was mounted and cemented to the first molar and canine teeth. Distraction was started the same day at the rate of 0.4 mm twice a day and continued until adequate movement of the canine teeth was achieved. The device was then removed, and orthodontic therapy was continued with fixed appliances. RESULTS: The distraction rate and the device were well tolerated by all of patients. No anchorage loss in the second premolar and first molar teeth, root resorption, dental ankylosis, discoloration, or loss of vitality was detected. CONCLUSION: The concept of distraction osteogenesis for rapid orthodontic tooth movement is promising and feasible for clinical practice.     

Influence of antifungal polyenes on the adhesion of Candida albicans and Candida glabrata to human epithelial cells in vitro

Candidal adherence to mucosal surfaces is considered as the first step in the pathogenesis of oral candidiasis. We examined the effect of antifungal polyenes, amphotericin B, nystatin and natamycin, at sublethal and minimum inhibitory concentrations (MICs) on the adherence of Candida albicans and Candida glabrata to HeLa cervical carcinoma and HSC-3 oral squamous cell carcinoma cells. A total of six oral Candida isolates were used throughout the study. Two Candida strains, C. albicans (44990) and C. glabrata (MYA-275) were obtained from ATCC. Four Candida strains, C. albicans 19 and 24 and C. glabrata 15 and 21, were isolated from patients with documented Candida-associated denture stomatitis. Cells were either incubated with Candida in the presence of the drug, or pre-incubated with yeasts and exposed subsequently to the drug. In the drug-free controls, the mean number of C. albicans yeasts associated with HeLa cells obtained from all experiments (130.1±10.1 yeasts/mm²) was significantly greater than that for HSC-3 cells (114.7±10.1 yeasts/mm²; P<0.025). For C. glabrata, the mean adherence to HeLa and HSC-3 cells was 84.4±5.5 and 84.4±3.3 yeasts/mm², respectively, and these values were not statistically different (P>0.4). Candidal adherence was significantly reduced when the tested polyenes were present during the “adherence phase”. The obtained values were significantly different from the controls, except for the effect of nystatin at the MIC on the adherence of C. glabrata strain MYA-275 to HeLa cells (P<0.375). Amphotericin B had the highest effect against both Candida species, reducing adherence by 50 and 60%, at the MIC and sublethal concentrations, respectively. The susceptibility of cell-associated Candida to polyenes was decreased markedly and the treatment did not result in significant detachment of adherent yeasts. The reduction in adherence was between 2 and 10%, when compared to the drug-free controls. These findings suggest that sub-therapeutic levels of polyenes that are likely to persist in the oral cavity following topical treatment may modulate candidal colonization when present during the “adherence phase”.     

Antibacterial activity of two adhesive systems using various microbiological methods

PURPOSE: To compare the antibacterial activities of two dentin bonding systems (DBS), Clearfil Protect Bond and Xeno III, by agar well, paper and dentin disks, and a cavity tooth model. MATERIALS AND METHODS: For the well technique, the test materials were filled in the agar wells inoculated with Streptococcus mutans (ATCC 25175). The paper disks were embedded in adhesives and placed on the seeded agar plates for the second technique. The adhesives were applied on the dentin disks and placed in holes in the plates for the third technique. After 48 h, the zones of inhibition were measured. In the cavity tooth model test, 3 cavities were prepared in the flat occlusal dentin of extracted human molars. The teeth were left in S. mutans for 72 h to allow bacterial invasion. The DBS were applied in the same manner as in clinical application on each of the two infected cavities and the third was left unapplied for control. The teeth were kept in saline for 72 h. Standard amounts of dentin chips were obtained from the cavity walls and the number of bacteria recovered was counted. RESULTS: The results were analyzed by factorial ANOVA and Dunnett C test. Clearfil Protect Bond primer exhibited the greatest inhibition zones followed by Consepsis and unpolymerized Xeno III in all the techniques tested (p < or = 0.05). Clearfil Protect Bond resulted in significantly less bacterial recovery than Xeno III by the tooth cavity method (p < or = 0.05). CONCLUSION: Clearfil Protect Bond was found to be the most antibacterial material with all the techniques used. Furthermore, Clearfil Protect Bond was able to inactivate the bacteria in the cavity more effectively than Xeno III.