JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2010 | Volume:22 | Issue:1 (74)|Papers Count:12

Background and Aim: Description of relationship between dental and skeletal parameters can help diagnosis and treatment of malocclusions. This study evaluated the relationship between facial height and vertical and sagital position of anterior teeth.Materials and Methods: The lateral cephalogerams of 89 patients between ages of 14 to 18 years old were studied. The study casts were analyzed then samples were divided into 2 groups of with or without crowding. Cephalograms were traced and Pearson correlation was determined between parameters that explain facial dimensions and parameters that showed sagital and vertical position of anterior teeth.Results: High correlation was found between ANB and U1 to SN, U1 to FH, and U1 to NA (mm). SNB had also correlation with U1 to FH and U1 to SN. Additionally, Jaraback index showed a great correlation with L1 to MP, IMPA and SNB. FMA was similarly correlated with IMPA and FMIA. Significant correlation was detected between basal angle and IMPA (P<0.001). The remaining subjects did not have crowding and demonstrated high correlation between ANB and L1 to NB. SN-GoGn displayed a great correlation with SNB and FMIA. U1 to FH was highly correlated with FMA, SN-GoGn and L1 to MP. High correlation was observed between L1 to NB (mm) and L1 to MP (P<0.001).Conclusion: There was correlation between the position of anterior teeth and facial dimensions that confirms the existence of balance between dentofacial parts. Therefore, establishment of equilibrium is essential for stability of treatment results.

Background and Aim: Some studies have reported packable composite has good mechanical properties including less stress, polymerization shrinkage and lower coefficient in thermal expansion, but it’s adaptation to cavity walls is not so good. This study evaluated the thermal cycling and Mechanical loading on microleakage of packable composite using in-vitro method.Materials and Methods: Forty eight bovine incisors were selected; Cl II cavity preparations were performed. The teeth were etched with 37% phosphoric acid. After etching, the teeth were rinsed with distilled water and dried with cotton pellet. Single bond (3M) adhesive system was applied next according to the manufacturer’s instructions. The surface was light-cured (Intensity 520 MW/cm2) and the cavities were filled with P 60 composite (3M). The teeth were randomly divided into two groups and two subgroups (n=12). Each group was treated with different thermal and mechanical load cycling. The entire surface of each tooth was coated with three layers of Nail polish, except for the 1-mm width around the cervical margin. The teeth were immersed in 2% fushin solution for two hours and then embedded in acrylic resin. Then they were hemi-sectioned longitudinally in a mesio-distal direction through the center of the restoration. The half tooth specimens were evaluated according to the amount of dye microleakage by means of a 40×magnification. Statistical analysis was conducted using SPSS software, and Kruskal-Wallis test.Results: No significant difference was detected between the four groups (P>0.05).Conclusion: According to the results of this study, thermo cycling and mechanical loading showed no effect on microleakage.

Background and Aim: Lichen planus is a common chronic inflammatory disease of skin and oral mucosa. The aim of this study was to determine the stress score and mean salivary cortisol level in patients with oral lichen planus.Materials and Methods: Samples were divided into two groups. The experimental group had 20 patients having oral lichen planus and control group with 20 individuals without any oral lesions. In order to determine the stress score, the Kattel anxiety scale was used. This scale contains 40 questions about ordinary problems that may be present in daily life. Spitting technique was used for collection of saliva samples in both groups. The samples collected between 9 and 10 AM. They were analyzed for the level of salivary cortisol with enzyme linked immunosorbent (ELIZA) assay. Paired sample T test was used for data analysis.Results: The mean level of anxiety state was 6.65 in case group and 5.6 in control group. The difference was not statistically significant (P=0.13). The mean level of salivary corlisol in case group was 3.15 and 3.63 in control group. The difference was not statistically significant (P=0.16) either.Conclusion: The mean salivary cortisol level in patients with oral lichen planus was less than healthy individuals. However, the stress scores in case group was slightly higher than control group. Thus in addition to traditional treatment of OLP patients, psychological treatment may also be needed. This study showed that there was no correlation between salivary cortisol concentration and stress level.

Background and Aim: Dry mouth is a major complaint of many elderly individuals especially those who are in the menopausal period. Although the exact mechanisms that mediate xerostomia have not been firmly established, sex steroid hormones appear to play a considerable role in the physiology of the human oral cavity. The aim of this study was to investigate the serum progesterone level in menopausal women with oral dryness feeling.Materials and Methods: A case-control study was carried out on 70 selected menopausal women aged 42-78 years with or without dry mouth (35 case and 35 controls) conducted at the Oral Medicine Clinic of Tehran University of Medical Sciences. Serum concentration of progesterone was assessed by enzyme-linked immunosorbent assay (ELISA). Statistical analysis using Spearman and Student’s unpaired t-tests were used.Results: The mean concentration of serum progesterone was significantly lower among the cases (30±10 pg/ml) than in control group (171±70 pg/ml, P=0.026). There was a negative correlation between serum progesterone concentration and severity of oral dryness feeling (r=-0.295; P<0.05).Conclusion: The results showed that subjects with dry mouth had decreased serum level of progesterone compared with those without dry mouth, which suggests an association of progesterone with symptoms of oral dryness.

Background and Aim: Angiogenesis is known as the outgrowth of new blood vessels from preexisting vasculature and plays an important role in different aspects of tumor growth and metastasis. Microvessel density (MVD) represents angiogenesis in neoplastic tissues and is generally employed as a useful tool for its measurement. The aim of the present study was to evaluate MVD in salivary gland mucoepidermoid carcinomas (MECs) and to assess its relation to histologic grade.Materials and Method: In this cross-sectional study, 30 parotid and minor salivary MECs were graded under a light microscope according to the AFIP criteria. All specimens were immunohistochemically stained with monoclonal antibody against CD34. MVD was determined by counting all positively-stained cells or cell clusters in 10 high-power-fields, selected from the most vascularized areas. The results were analyzed using one-way ANOVA and Scheffe post-hoc tests.Results: MVD was expressed as the mean number of microvessels per high-power-field. A statistically significant correlation was observed between MVD and MEC grade (P=0.001). Microvessel density was significantly lower in grades I (11.12) and II (13.66) compared to grade III (23.50) tumors. The difference between grades I and II neoplasms was not significant (P=0.725).Conclusions: According to the results obtained in the present study angiogenesis may have an important role in the pathogenesis of parotid and minor salivary gland MEC and may be useful in the prediction of its biologic behavior.

Background and Aim: Tooth sensitivity is common after vital tooth bleaching. Desensitizers are available as a component of bleaching agents or separated materials. The aim of this invitro study was to evaluate the effect of “GC tooth Mousse (GCTM)” on bond strength of composite resin to bleached enamel.Materials and Methods: This experimental study was conducted on 48 freshly extracted sound molars. Samples were divided in 4 groups (n=12). In group 1 (negative control) composite resin was bonded on the buccal enamel surfaces. Specimens in groups 2 and 3 were bleached for 6 hrs/d for 5 consecutive days (Day white ACP). Group 2 specimens were immediately bonded with composite resin. In group 3, GCTM was used for 30 min in 5 consecutive days and then rinsed after each procedure. On the 5th day the specimens were bonded using composite resin. In group 4, the specimens only received GCTM and then composite resin cylinders were bonded. After 500 rounds of thermocycling, shear bond strength of the samples were measured and the findings were analyzed by Two-way ANOVA and Tukey-Keramer tests. (a=0.05)Results: Variance analysis showed significant differences between groups (P=0.0). The highest and the lowest bond strengths were found in groups 1 and 2 respectively. The Tukey-Keramer analysis showed that using GCTM after bleaching had significant effect on composite shear bonding strength. (P<0.05) Conclusion: Within limitations of this invitro study, using the GCTM as a desensitizer agent either alone or during bleaching affected the composite resin bond strength to enamel. More investigation is recommended.

Background and Aim: The aim of this study was to compare ten porcelain surface preparation procedures for acquiring reliable procedure for steel bracket bonding.Materials and Methods: This experimental study was conducted with100 steel brackets (3M) bonded to 100 uniform porcelain fused to metal uniform disks by ten different porcelain surface preparation methods with Unite composite.The procedures were: 1) Glazed layer preservation+silane, 2) Glazed layer preservation+phosphoric acid+silane, 3) Glaze removing with diamond bur, 4) Glaze removing with diamond bur+silane, 5) Glaze removing with sandblast, 6) Glaze removing with sandblast+silane, 7) Hydroflouric acid etching, 8) HF etching+silane, 9) combination of 5 and 7, and 10) Combination of 5 and 8.After bonding, samples were preserved in wet environment and then they were thermocycled.Shear bond strength was measured with Dartec machine. Surface of samples were evaluated under light microscope after bracket removal. Comparison of shear bond strengths was done by one way ANOVA and Dunnett’s C tests. For evaluation of fracture pattern and the quality of porcelain surface after bracket removing, Kruskal Walis and Manwitney tests were used.Results: Adequate shear bond strength was not attained by 1st, third and fifth procedures. Other procedures can produce adequate or extra shear bond strength in orthodontic needs. Only in two groups, damage to porcelain was zero or minimum (P<0.0005) and damage was higher in other groups.Conclusions: Results showed two reliable procedures (second and seventh procedures) for bonding of steel brackets to porcelain especially in anterior regions that undamaged porcelain is critical.

Background and Aim: There are many unknown systemic and local factors influencing tooth growth and development. Likely, tooth eruption may be under such influence as well. Despite delayed tooth eruption, studies on early tooth eruption are very scarce. Therefore, this study was conducted in order to evaluate the relationship between intelligence quotient (IQ) and early tooth eruption in normal children (with no disease or disorder).Materials and Methods: By using study criteria, 44 children were recruited after oral examination of 652 children (337 boys and 315 girls). Oral examination was conducted by one dentist using plastic disposable mirror, under day light. The Raven’s test was taken blindly under standard conditions for all subjects by a psychologist. “Case” subjects were defined as individuals who had partially or fully erupted molars earlier than the expected normal time. “Control” subjects were similar to “cases” but without erupted molars. Statistical analysis was conducted using student T-test.Results: The intelligence test was performed on 44 subjects consisting of 22 boys (11”case” and 11”control”) and 22 girls (11”case” and 11”control”). IQ in two sexes did not have significant difference (P<0.05). But the mean IQ difference between “case” and “control” groups was about 11 points that was statically significant (P<0.01).Conclusion: Healthy children with early first permanent molar eruptions, have higher IQ compared to their peers (P<0.01). This criterion may be used to identify high IQ children for provision of special care and training for faster advancement of individual and society.