Frontiers in Dentistry
Year:2007 | Volume:4 | Issue:3|Papers Count:7

Objective: The aim of the present study was to evaluate the structure and distribution of Glycoconjugates during molar tooth germ development in mice Materials and Methods: Sixteen tooth germs were obtained from BALB/c mice embryos 15 to 18 days post-gestation and fixed in 10% formalin. After routine tissue processing, 5 mm sections were cut and stained with BSA1-B4 and PNA using the lectin histochemical method. All slides were evaluated by light microscopy.Results: Both lectins showed positive reaction in the tooth germ but with spatiotemporal differences. During bell stage, the reaction was strong with BSA1-B4 but moderate with PNA. Strong PNA uptake was observed in the odontoblastic and ameloblastic nuclei along with the apical cytoplasm of the ameloblasts.Conclusion: Although the lectins that were used in the present study recognize the same terminal sugar residue, they reacted with different disaccharide sequences with various penaltomer sugars. Therefore it may be assumed that the pattern of affinity for different parts of the developing tooth germ such as ameloblasts and odontoblasts is different in various lectins.

Objective: The aim of the present study was to evaluate unstimulated salivary flow rate and oral symptoms in menopausal women. Materials and Methods: A total of 200 individuals including 100 women in their meno-pause (case group) and 100 men in the same age range (control group) participated in this analytic descriptive investigation. None of the patients were being treated for any systemic disease or taking any medication. Unstimulated salivary flow rate was measured using the spitting method and the prevalence of oral symptoms was evaluated by filling out a ques-tionnaire. The results were analyzed with ANOVA, chi-square and Student’s t-test (P<0.05). Results: The average of unstimulated salivary flow rate was 0.127 ml/min (SD=0.057) in women and 0.214 ml/min (SD=0.105) in men. The prevalence of dry mouth was 50% ver-sus 32%, difficulty in eating dry foods 31% versus 8%, burning sensation in oral mucosa 3% versus 0%, taste reduction, 4% versus 2% and bitter or metallic taste 16% versus 8% in female and male subjects, respectively. Conclusion: A significant difference in salivary flow rate and prevalence of oral symp-toms was found between the two groups (P<0.05). Reduced salivary flow rate and a high prevalence of oral symptoms in menopausal women may be related to the hormonal altera-tions that occur during this period.

Objective: The planning of orthodontic treatment within a public health system requires information on the orthodontic treatment needs of the population. The aims of this study were to assess the student, parent and clinician normative need and demand for orthodon-tic treatment in a sample of Iranian students using the IOTN and to compare the treatment need levels according to sex and socio-economic status of the students and parents in ur-ban and rural areas. Material and Methods: A sample of 427, 17-year-old students was selected randomly from schools in Abade. A questionnaire of family socioeconomic status was proposed to the parents. All the students were examined according to the Aesthetic and Dental Health components (AC and DHC) of Index of Orthodontic Treatment Need. Students' and par-ents' perceived need was also assessed using AC. Results: According to DHC classification, 18.7% of the students were in the "no need"; 35.6% in the "border line" and 45.7% in the "definite need" groups. The same categories for students assessed by the dentist were 66%, 30.2% and 3.7% respectively. AC assess-ment by students and parents entitled even more studentsin "no need" category. Sex and family income were the major factors in predicting orthodontic treatment demand (P<0.05). Conclusion: Orthodontic demand was highly related to the AC score and this component is of more value in predicting students demand instead of DHC.

Objective: Osseous defects arounddental implants are often seen when implants are placed in areas with inadequate alveolar bone, or around failing implants. Bone regenera-tion in these areas using bone grafts or its substitutes may improve dental implants prog-nosis. The aim of this study was to prepare and characterize the bioactive glass nanopow-der and development of its coating for treatment of oral bone defects. Materials and Methods: Bioactive bioglass coating was made on stainless steel plates by sol-gel technique. The powder shape and size was evaluated by transmission electron mi-cropscopy, and thermal properties studied using differential thermal analysis (DTA). Structural characterization techniques (XRD) were used to analyze and study the structure and phase present in the prepared bioactive glass nanopowder. This nanopowder was immersed in the simulated body fluid (SBF) solution. Fourier transform infrared spec-troscopy (FTIR) was utilized to recognize and confirm the formation of apatite layer on prepared bioactive glass nanopowder. Results: The bioglass powder size was less than 100 nanometers which was necessary for better bioactivity, and preparing a homogeneous coating. The formation of apatite layer confirmed the bioactivity of the bioglass nanopowder. Crack-free and homogeneous bioglass coatings were achieved with no observable defects. Conclusion: It was concluded that the prepared bioactive glass nanopowder could be more effective as a bone replacement material than conventional bioactive glass to pro-mote bone formation in osseous defects. The prepared bioactive glass nanopowder could be more useful for treatment of oral bone defects compare to conventional hydroxyapatite or bioactive glass.

Objective: The use of HEMA as a biocompatible material in dentin bonding systems and its potential for clinical applications has been well established. Excess water can affect conversion of bonding resins. The aim of this study was to survey the effect of water on the degree of conversion of HEMA by Fourier Transform Infra-red Spectroscopy (FT-IR).Materials and Methods: In this experimental study, distilled water was added in amounts of 0, 0.05, 0.1, 0.2, and 0.4 ml to 1 ml of curable HEMA solution. Six repetitions per wa-ter ratio were made and investigated. Each sample was polymerized for 60 seconds. De-gree of conversion was obtained from the absorbance IR-Spectrum of the materials before and after polymerization by FT-IR spectroscopy. One way ANOVA and Tukey-HSD were carried out to compare and detect any differences among groups. Results: Statistical analysis indicates highly significant difference between pairs of groups at level (P<0.001). The results showed a trend of decreasing in HEMA conversion with increasing water. Degree of conversion changes significantly within the 0.05 ml to 0.2 ml water range. However, degree of conversion did not change after reaching 0.02 ml and before 0.05. Conclusion: Degree of conversion of HEMA decreased by increasing water. The most dramatic effect of water on the polymerization process occurs within a range which exists under clinical conditions. The reason that the degree of conversion did not show signifi-cant result before 0.05 ml may be related to the hydrophilic nature of HEMA.

Objective: Intrusion as a type of tooth movement is managed by different mechanothera-pies during various treatment stages. The morphology of the apical third of the teeth to be intruded plays an important role in the risk of root resorption due to the raise of stresses.The main goal of this study was to compare various types of apical third of the teeth while loaded by an intrusive force. Materials and Methods: Four 3D Finite element models were designed with all support-ing structures. Normal, needle form, short and sharp apices were considered. Intrusiveforces of 0.5 N were applied and the VonMises stress along the mesial side of the root was assessed. Results: A tendency to show increased stresses at the cervical area of the teeth was no-ticed. The lowest stress was noticed in the blunt apex and the highest findings were shown to be in the needle form apex model. Conclusion: Normal variation in apical third of the teeth in intrusion can cause an in-creased stress level and also increased chance of root resorption which should be consid-ered carefully in force applications.

Objective: The aim of this study was to evaluate the clinical efficacy of an herbal medi-cine, Piascledine, on the treatment of chronic periodontitis. Materials and Methods: Twenty-four patients with chronic periodontitis participated in this interventional case control investigation. After initial screening the subjects were di-vided into case and control groups. Clinical measurements including plaque index (PI), bleeding on probing (BOP), probing pocket depth (PPD), bone level (BL) and clinical at-tachment level (CAL) were recorded for both groups, before and one month after scaling and root planing (SRP). The case group received 300 mg Piascledine capsules once a day for three months and the control group was only treated with SRP. The measurements were repeated in both groups at the 3 and 6 month recall visits. Results: Improvements were observed in all clinical parameters in both groups during the study period. PI as a covariate factor showed no significant difference between the two groups (P>0.05). On the other hand CAL, BOP, PPD and BL showed reduction in all pa-tients, but no significant difference was found between the two groups. Conclusion: According to the results obtained in the present study, Piascledine does not seem to have a favorable effect in the treatment of chronic periodontitis.