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.     

The effects of nitanium maxillary expander appliances on dentofacial structures

The aim of this study was to determine the sagittal, transverse, and vertical effects of a Nitanium maxillary expansion appliance on dentofacial structures in patients with bilateral posterior cross bites in the permanent dentition. For this purpose, and without distinguishing the skeletal classification, a total of 16 patients (4 boys and 12 girls) with a mean age of 13.8 years and a bilateral posterior crossbite in the permanent dentition were chosen. Lateral and frontal cephalometric radiographs, maxillary and mandibular plaster models and periapical radiographs were obtained from each patient at pretreatment (T1), post-treatment (T2), and at the end of the retention period (T3) time points. The measurements that were obtained from the lateral and frontal cephalometric radiographs and maxillary and mandibular plaster models were evaluated by a Wilcoxon paired 2-sample test. This test compares 3 pairs of time points, the pretreatment (T1) and posttreatment (T2), the pretreatment (T1) and post retention (T3), and the post-treatment (T2) and post retention (T3). Periapical radiographs were used to demonstrate changes in the midpalatal suture. Skeletal expansion occurred simultaneously with dentoalveolar expansion in the transverse plane with the Nitanium maxillary expansion appliance. The upper incisors were extruded and retroclined. Also, the extrusion of the upper first molars caused the mandible to rotate backward and downward. This resulted in an increased vertical dimension of the lower face. It was clinically observed that the posterior cross-bite and mesiopalatal rotation of the upper first molars were improved and that the crowns of these teeth were moved slightly to the distal side.     

Cytotoxic effects of four different endodontic materials in human periodontal ligament fibroblasts

The purpose of this study was to compare the cytotoxicity, induced apoptosis and/or necrosis, and apoptotic mechanisms in human periodontal ligament (PDL) fibroblasts treated with four different endodontic materials: White ProRoot mineral trioxide aggregate (MTA) (MTA/Dentsply; Tulsa Dental, Memphis, TN), Diaket (ESPE, Seefeld, Germany), Endion (VOCO, Cuxhaven, Germany), and CYMED 8410 (NANO, Kaohsiung, Taiwan). The effects of these four materials on the viability of PDL fibroblasts were determined by MTT (3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-SH-tetrazolium bromide) assay. Apoptotic pathways were evaluated via several mechanisms. Exposure to MTA for 24, 48, and 72 hours resulted in no significant differences in MTT reduction and viable cell number compared with controls. However, treatment of PDL fibroblasts with Diaket, Endion, and CYMED 8410 for 24, 48, and 72 hours resulted in cytotoxicity with MTT and a reduction of viable cell number with trypan blue dye exclusion test compared with controls (from p < 0.05 to p < 0.001). Annexin V-FITC/PI staining showed that Diaket, Endion, and CYMED 8410 induced higher percentages of apoptosis and/or necrosis than in controls (45.6%, 25.5%, and 6.3%, respectively). Results of cell-cycle analyses were concordant with annexin V-FITC/PI staining findings. These results suggest that MTA is a very biocompatible filling material. However, Diaket, Endion, and CYMED 8410 are toxic to PDL fibroblasts in vitro. The main form of cell death induced by these filling materials was determined to be apoptosis and/or necrosis.     

Epithelial cells in PDL are critical in resuming the integral relation between tooth root and supporting bone after trauma--a transplantation experiment

OBJECTIVE: The aim of this study was to determine the response of the residual epithelial network following traumatic breakdown of the periodontal ligament (PDL). METHODS: Mandibular incisor sections with PDL (experimental) and sections denuded of PDL (control) from 4- to 6-week-old Wistar-Furth rats were transplanted into the defects created in the frontal bone of the recipient syngeneic rats. At intervals, the defects with implanted teeth roots were collected and processed for histological and biochemical examination. Immunolocalization of epithelial cells was performed to monitor their phenotypic changes during transplantation healing period. RESULTS: (1) Histological observation of the experimental sample revealed the sequence of cellular response characterized by an initial degeneration of PDL followed by a proliferation of granulation tissue. There was also a marked odontoblastic reaction with extensive deposition of regular dentine within the pulp chambers. In the control group, initial signs of bony fusion with dentine led to an extensive ankylosis and bone replacement between roots and defects. (2) Immunostaining indicated that, in experimental groups, the pattern of regularly spaced epithelial cells lying in close approximation to the root surface was distinct 10 days post-transplantation but became diminished afterwards. The immunoreaction against epithelial cells was negative in the control. CONCLUSION: Residual PDL is essential to prevent ankylosis after trauma and epithelial cells may facilitate the re-establishment of root-PDL-bone complex by transforming into mesenchymal cells.     

The inhibition of mast cell degranulation in monkey gingiva by disodium cromoglycate

The effect of Syrijet applied disodium cromoglycate (DSCG) on mast cell degranulation and on gingivitis was investigated in rhesus monkeys. Mast cell counts were obtained by tracing representative areas from specially stained tissue sections and visually counting mast cells per unit area. Results revealed that while the drug inhibited mast cell degranulation, this was not associated with any detectable change in gingivitis in the time period studied.
D.S.C.G. should provide an invaluable tool for the continued investigation of the role of mast cells in gingivitis.     

Electrocatalytic oxidation of hydrazine on a carbon paste electrode modified by hybrid hexacyanoferrates of copper and cobalt films

A stable electroactive thin film of hybrid copper-cobalt hexacyanoferrate (CuCoHCF) was electrodeposited on a carbon paste electrode by cyclic voltammetry. The modified electrode exhibits good catalytic activity for the oxidation of hydrazine at a reduced overpotential with good sensitivity in the wide concentration range 0.1–12 mM hydrazine. A Tafel plot, derived from voltammograms, indicated a one-electron charge transfer process to be the rate-limiting step and the overall number of electrons involved in the catalytic oxidation of hydrazine was found to be 4. The CuCoHCF modified-electrode exhibited stable electrochemical responses in a wide pH range 2–10 and showed excellent electrocatalytic activity toward the oxidation of hydrazine in 0.1 M phosphate buffer, pH 7. The diffusion coefficient of hydrazine and rate constant for the catalytic reaction were also evaluated. Finally the proposed modified electrode exhibited several attractive features, such as simple preparation, fast response, good stability and repeatability and could be applied as an amperometric sensor for hydrazine.     

Guided tissue regeneration in conjunction with hydroxyapatite-collagen grafts for intrabony defects

Abstract This clinical and radiological study evaluated the healing of 3 + 2 + 1 wall-combined intrabony defects treated using the guided tissue regeneration technique (GTR) with and without hydroxyapatite-collagen alloplastic graft materials (HAC), in comparison to that of HAC alone and conventional flap surgery (CF), 40 interproximal defects with probing depth >6 mm were treated in 18 adult periodontitis patients of ages 35–60 years. After non-surgical therapy, the defects were randomly grouped into 4 groups of 10 defects each. These groups were designated: (1) expanded polytetrafluoroethylene membrane (e-PTFE), (2) e-PTFE+HAC. (3) HAC alone and (4) CF. At 6 months, the following changes in parameters were recorded. Mean PPD reduction for each group was 5.83, 5.85, 3.80 and 3.17 mm respectively. PPD reduced very significantly in all groups (P<0.01), the highest and lowest reductions in PPD being for the e-PTFE + HAC and CF group respectively. Comparison between the 4 groups showed higher PPD reduction in both membrane groups than in either of the non membrane groups (p<0.05) with the difference between the e-PTFE and CF groups being very highly significant (p<0.001). Mean attachment gain for the 4 groups was 3.70. 3.80. 2.60 and 2.1 mm, respectively. Similarly attachment gain for all groups was very significant (p<0.01) and the highest and lowest attachment gains were for the e-PTFE+HAC and CF group respectively. Both membrane groups showed significantly more attachment gain than the CF group (p<0.05). Change in probing bone level (BL) for the 4 groups was 1.60. 1.90. 1.0 and 0.65 mm respectively. Again the highest changes in BL were recorded for the e-PTFE + HAC group. Significant differences were found between both membrane groups and the CF group (p<0.05). Radiological evaluation using standardized radiographs and millimeter grids showed change in radiographic bone level at the deepest point of the defect on the radiograph to be 1.50, 1.55, 0.85 and 0.60 mm, respectively and this was significantly higher in both membrane groups than in the CF group (p<0.05). This study therefore found e-PTFE membranes both alone and when combined with HAC to lead to more attachment gain and bone fill than did HAC alone or CF. It found HAC combined with e-PTFE to perform better although not significantly better than e-PTFE alone.     

A study of manual toothbrushing skills in children aged 3 to 11 years

The aim of the study was to evaluate toothbrushing management and ability of children in relation to age and gender. The study population consisted of 75 children and were divided into three equal groups as 3-5, 6-8 and 9-11 years of age. The grip type during toothbrushing was recorded on videotape, The most preferred grip types were distal (73%) followed by power (43%) and oblique grips (29%). There were a statistically significant differences between age groups and the grip types (p < 0.0041) but no significant difference was seen between boys and girls in grip preferences (p > 0.05). The mean duration of toothbrushing was shorter in 3-5 years of age group (28 seconds) than the 6-8 and 9-11 age groups (35 and 47 seconds respectively).     

Effect of misoprostol, a prostaglandin E1 analog, on orthodontic tooth movement in rats.

The purpose of this study was to investigate the effects of oral administration of misoprostol, a prostaglandin E1 analog, on orthodontic tooth movement and root resorption in rats. Sixty-four male Sprague-Dawley rats that initially weighed 250 +/- 20 g were used in this study. The animals were randomly assigned to 1 of 6 experimental and 2 control (nonappliance and appliance) groups. The experimental groups received 2.5, 5.0, 10.0, 25.0, 50.0, and 100.0 microg/kg misoprostol by gastric lavage every 24 hours for 2 weeks. A fixed orthodontic appliance consisting of a nickel-titanium closed-coil spring, 5.0 mm long was ligated between the maxillary right incisor and the maxillary right first molar. The initial activating force was 60 g. For analysis of root resorption, 99 maxillary right and left first molars from 61 animals were chosen. Serial histologic sections of the mesial root of the maxillary first molars were made, and histologic analysis of root resorption on the mesial and distal surfaces was performed. The results showed that oral misoprostol did increase the amount of orthodontic tooth movement in all the experimental groups compared with the appliance control group. This increase was statistically significant in doses of 10.0, 25.0, 50.0, and 100.0 microg/kg (P <.001). However, there were no statistically significant differences among these 4 different doses. There were no statistically significant differences in the amount of root resorption among the groups. However, a trend toward more root resorption was registered. On the basis of these findings, oral misoprostol can be used to enhance orthodontic tooth movement with minimal root resorption.     

Use of casting tape for support of an extraoral impression

This article describes a technique for using casting tape to support irreversible hydrocolloid material when making extraoral impressions to increase patient comfort, save time, and produce less tissue distortion.