مجله تحقیق در علوم دندانپزشکی
سال دهم شماره 2 (پیاپی 36، تابستان 1392)

Iranian orthodox black tea extract has been used widely in Iranian traditional medicine and society. The present investigation was carried out to study the induction of apoptosis and cytotoxic effects of hydromethanolic crude extract of Iranian orthodox black tea against oral squamous cell carcinoma (KB cell line). This experimental In vitro study was done on KB cells which were used as a model for oral squamous cell carcinoma cells. Collected leaves were dried and powdered, then were soaked in 70% hydromethanol solvents. The cytotoxic rate and viability percentage of different concentration of crude extract on cultured cells were measured using the MTT assay. ELISA assay was used to measure the induction of apoptosis after 24 h in IC50 of hydromethanolic crude extract. Also, TUNEL test was applied to confirm the induction of apoptosis in treated cells. ANOVA test was used for the analysis of required data. MTT assay result revealed that hydrometanolic crude extracts of Iranian orthodox black tea had growth inhibitory and cytotoxic activity on oral squamous cell carcinoma (KB cell line). After 24 h, IC50 of hydromethanolic crude extract was 446.08±12.4 𝜇 g/mL. ELISA assay results revealed the induction of aptosis to be 34%. Iranian orthodox black tea extract can exert growth inhibition and induce cell death apoptosis on oral squamous cell carcinoma in all concentrations.

The production and consumption of probiotic products have been growing over the past few years.. Yogurt is one of the most common vehicles for probiotics. The potential of these products for reduction of salivary counts of streptococcus mutans has been the subject of many studies in recent years. The aim of this study was to investigate the effect of a probiotic yogurt in comparison with ordinary yogurt on the salivary counts of Streptococcus mutans. This study was conducted as a "clinical trial Double-blind randomized crossover", in which 30 healthy dental students were participated. The salivary counts of streptococcus mutans were determined in participants by using the mitis salivarius agar environment at the start, following the three interventions (probiotic yogurt, ordinary yogurt and non of them), and after wash out periods. The data were analyzed in terms of quality and quantity respectively by sign and kruskal wallis statistical tests. There was a statistically significant reduction in the level of salivary streptococcus mutans counts, following 3 weeks of intervention by probiotic yogurt consumption (p< 0.01). Regular plain yogurt consumption for 3 weeks resulted in a statistically significant increase in the level of salivary streptococcus mutans counts (p< 0.01). No significant alterations of the salivary streptococcus mutans counts were observed in the third group which didn’t have any intervention during this period (p<0.9). Consumption of probiotic yogurt will result in reduction of the salivary streptococcus mutans counts which is maintained for a period of two weeks.

The objective of this study was to measure the absorbed dose in target organs using conventional and digital panoramic radiography. In this experimental cross-over study, the Rando phantom of the Atomic Energy organization of Iran(AEOI) was exposed 54 times using conventional (Cranex Tome -Sordex), and digital panoramic (Cranex D-Sordex). radiography The absorbed doses were measured by a dosimeter (TLD’s) in the following areas: Thyroid gland, left and right Parotid and Submandibular glands, Sublingual gland, bone marrow of left and right maxilla and mandible. TLD’s were coded and the absorbed doses for each organ was determined under standard conditions in AEOI. Data was analyzed by using t-test and MANN-U-WHITNEY. In this study, the total absorbed dose in conventional radiography was 0.82±0.06 (mSiv) compared to 0.42±0.04 (mSiv) in digital radiography. The difference was statistically significant (P< 1%)and the highest absorbed dose was reported to be in Submandibular glands The lowest absorbed dose was seen in the Thyroid gland. The difference was found to be statistically significant (P< 0.01). Digital radiography can reduce the absorbed dose to critical organs.

The role of sucrose in pH decline in dental plaque and its significance in the development of caries has been established. There are various reports on the effect of various drugs on the pH of dental plaque as well as considerable gaps in the existing information in the country. This study compared the effects of five types of common syrups for children (250 amoxicillin suspension, acetaminophen syrup, diphenhydramine syrup, and children’s cold and multivitamin syrup) with a solution of 10% sucrose on the pH of dental plaque.

In this Single- blind randomized crossover clinical trial study, 10 healthy dental students were selected with an average age of 23.7± 1.10 and DMFS=10±1.82. Changes in pH were recorded by a digital pH meter at baseline and time intervals of 2.5.7, 10, 15, 20,30,40,50 and60 minutes following a 1min rinse with each medicine and 10% sucrose solution as a positive control. Statistical and data analysis was done using T-test (repeated measure ANOVA)and multiple comparisons (post Hoc).

The average pH of dental plaque was found to be the lowest at all times (from 6.64±0.38 to 6.39±0.39) in samples which took amoxicillin suspension. Significant difference was found between the medications and 10% sucrose solution up to 20 minutes (p<0.01). The pattern for pH changes was similar in almost all samples and it was reported to be below the critical levels.

All medications tested caused a decline in the pH of dental plaque. The maximum drop in pH was reported to be in the seventh minute. In almost all cases, the pH level never returned to the baseline values for 60 minutes after drug use.

The amount of fluoride uptake by teeth is considered as to be a criterion in the cariostatic properties of dental restorative materials. The aim of this study was to determine the amount of fluoride uptake by enamel of deciduous teeth from 3 types of self cured glass ionomers: Fuji II (GC Japan), Riva self-cure(SDI Australia) and SDS(Iran). This experimental study was conducted on thirty primary molars which were randomly divided into 3 groups. Each tooth was divided into buccal and lingual halves. Fuji II Glass-ionomer (GC Japan), Riva self-cure (SDI Australia) and SDS (Iran) were placed randomly on the surfaces of teeth in case group. All subjects were stored in artificial saliva (without fluoride) for a month and samples were obtained from each subject using Acid etch biopsy technique. The amount of fluoride and calcium in sample solutions were measured by potentiometer and atomic absorption spectrophotometer. The results were analyzed by t-test and ANOVA statistical tests. This study indicated that the amount of fluoride uptake by enamel of deciduous teeth from Fuji II Glass-ionomer was (146.85 ± 15.68 ppm which was significantly is higher than fluoride uptake from riva self cure (40.67±5.34 ppm) and SDS (83.68±6.40ppm) (P<0.001). Fluoride uptake by enamel of deciduous teeth was higher from Fuji II Glass-ionomer (GC Japan) in comparison with Riva self-cure(SDI Australia) and SDS(Iran).

Dentists can reduce errors of bridge's framework through controlling and reducing errors during impression. Open tray splitting impression is a method that it's precision is questionable. The aim of this study was evaluation of framework's marginal gap produced in direct impression with and without splinting. This experimental in vitro study was done on two parallel implants (regular Neck ITI), that inserted on left premolar and molar region mandibular model. Ten final impressions by open tray and ten final impressions with splinted technique were made. Marginal gap was measured with direct view method. We used SPSS 18 and T-Test for analysis. mean gap in splint and conventional methods were (43.87±11.35) µ and (87.30±34.50) µ, respectively. There was a significant difference between two methods (P<0.001). Also the marginal gap in distal and mesial retainer with splint method were significantly lower than conventional method (P<0.05). Marginal gap in splint method was lower. Because marginal integrity level of splint method was high, for final impression of implant supported bridge suggestion, however clinical procedure of this method is difficult.

Inadequate bond strength of resin cements to dentin appears to be a typical cause of failure in retention of fiber posts. In restoring endodontically treated teeth with fiber posts the cement-dentin interface is the weakest link. This study aims to compare the effect of self-etch and self-adhesive resin cements on shear bond strength of fiber posts to dentin. This in vitro experimental study included 40 mandibular premolars with a single canal. All samples received standardized endodontic treatment after meeting the inclusion criteria. They were randomly divided into four groups and a post space was prepared in each sample. A size two Match post RTD fiber post was cemented into each sample using CoreCem (RTD) in group A, Panavia F2 (Kuraray) in group B, Bis Cem (Bisco) in group C and Maxcem Elite (Kerr) in group D as cementing agents. All samples were then cut into two pieces. Each specimen was loaded with equal force using a Universal Testing Machine. The load was applied from the apical to the coronal portion of each sample until fracture occurred. The mean shear bond strength for two each group was recorded and statistically analyzed with ANOVA(one way) and Dunnett’s tests using SPSS. The mean shear bond strength was found to be as follows: Group A: (12.66 ±3.77) MPa Group B: (14.61±4.18) MPa Group C: (7.26±2.49) MPa Group D:(6.68±3.17)Mpa, Significant difference was demonstrated between shear bond strength of four groups (P=0.001). Mean bond strengths of resin cements in group A and B were not statistically different. Same results were shown when comparing cements in group C and D. However, cements in group A and B (self-etch) provided stronger bonds to dentin compared to group C and D (self-adhesive), the difference being statistically significant (P<0.05). The use of self-etch resin cements results in higher shear bond strength to dentin compared to self-adhesive resin cements.

Class II and Class III malocclusions have been reported to have a high incidence among the antero-posterior jaw anomalies. This study is aimed to evaluate the relation between the antero-posterior discrepancies and morphology of the cervical vertebra. This case control study evaluated 89 patients(aged 17 to 30 years old). The samples were matched based on vertical dimension indices such as SN-MP, MM, and Jarabak index. ANB index was used to divide the samples into 2groups as follows 1- Control group consisting of 39 subjects with normal growth pattern(ANB2+2 2- Case group with 20 Class II (ANB>4) subjects and 30 Class III (ANB<0) subjects.. Cervical vertebra morphology was assessed on lateral cephalograms and anomalies such as posterior arch deficiency and fusion were detected. Data were analyses by Binary logistic Regression, T test and Independent sample test. The prevalence of fusion was 35.9% in control group (normal growth pattern), 55% in Class II, and 73.3 % in Class III. The difference was statistically significant between control group and Class II malocclusion as well as Class III malocclusion. (p<0.003) (p<0.01). There was no significant difference in prevalence of fusion between Class II and Class III malocclusion groups. The prevalence of posterior arch deficiency was 5.5%, 15%, and 16.7 % in normal growth pattern, Class II, and Class III groups respectively. The difference.(p<0.8. p<0.9. p<0.5) There was a significant relation between anteroposterior discrepancies and cervical vertebra anomalies, especially for C2 and C3.

Excessive display of gum tissue during smiling is called gummy smile. This situation is caused by several factors including altered passive eruption. The purpose of this investigation is to determine the correlation between gummy smile and altered passive eruption (APE) in a young population of women in Esfahan. In this cross sectional study, 842 females aged between 20 and 30 were examined in Esfahan. They were asked to smile in voluntary and involuntary (emotional) states. Gingival display (more than 1mm during smiling) as well as length of the clinical crowns (short or normal) in anterior teeth were recorded in a table. Statistical analysis of the data was carried out using chi square. Results revealed that 223 subjects exhibited short clinical crowns and 619 had normal clinical crowns. Gummy smile was reported in 128 subjects during voluntary state and in 556 subjects in involuntary state. 148 subject didn’t have gummy smile. Chi square analysis showed a correlation between short clinical crowns and the type of smile. In voluntary state, gummy smile was seen in 22.4% of the subjects with short clinical crowns and in 12.6% of the subjects with normal crown length (P< 0.001 (Involuntary smiling resulted in gingival display in 68.6% of the subjects with short clinical crowns and in 66.7% with normal crown length (p= 0.61). There is a correlation between altered passive eruption and gummy smile during involuntary(emotional) smiling.

p53 is one of the most recognizing biomarkers has been studied in oral SCC and other human malignancies. This is a review study to assess the clinical relation between prognosis value of p53 protein and determining clinicopathological factors such as recurrence,patient survival, extent of local invasion, metastasis, tumor size and cell differentiation as well as other features of OSCC. A literature review articles using the databases such as Medline, Cochrane Library, Google scholar, Iran Medex, Scopus, Embase, and Science Citation Index; between 1995-2012 years,by keywords, Scc associated with prognosis, clinical outcome, and p53, which contains 30articles had been collected..At the next step, the articles were divided into two groups of before and after year of 2005 due to achieving more obvious results. The positive and negative relationship between p53 and prognosis of OSCC were analysed statistically by chi-square test. After statistical analysis, it would be clear that 83.3% of articles related to after 2005, confirmed the relationship of p53 expression and poor prognosis of OSCC vs this point was only 38.9% in the articles related to before 2005. The differences were statistically significant.(p<0.02) It seems that, majority of recent studies confirmed the relationship of p53 expression and poor prognosis of OSCC. So, this marker can be used for evaluation of prognosis in OSCC patients.

Presence of two palatal canals in the maxillary second molars is not prevalent and is reported to be 0.4-2%. In order to prevent missing this extra canal and failure of the root canal treatment, thorough knowledge of the root canal system is required. This article presents nonsurgical endodontic treatment of three maxillary second molars with two palatal canals. Radiographic interpretation is difficult in this region. Therefore, precise clinical examination of the pulpal space and the crown size is recommended to discover any unusual anatomic features like extra canals.

In recent years, bisphosphosonate related osteonecrosis of the jaw have generated great concern regarding increased number of occurrences of this side effect It is of paramount importance that every dentist approaches these patients with the necessary precautions to avoid further complications in the course of dental treatment. The goal of this report is to present a patient with BRONJ)Bisphosphosonate Related Osteonecrosis of the Jaw???) and review the most important details of the case. A 59 years old female was referred to department of oral and maxillofacial surgery with chief complaint of halitosis and infection at the site of dental extraction. She had a history of consuming alendronate, 80 mg daily during for 8 years. Jaw osteonecrosis accompanying oro-antral fistula has consequensced a dentoalveolar procedure in this area. She was treated by surgical approaches to remove necrotic bone and close soft tissue with the use of tissue expander and advancement flaps. After 30 months follow up there is not any problem with oral hard and soft tissues. With regard to this paper, it is paramount that we should consider the history of bisphosphonate consumption for prevention of BRONJ.