مجله تحقیق در علوم دندانپزشکی
سال یازدهم شماره 3 (پیاپی 41، پاییز 1393)

The main purpose of periodontal treatment is to alleviate the clinical symptoms of inflammation. Photodynamic therapy which consists of light source and photosensitizer is believed to be influential as an adjunct to the conventional treatment in periodontitis. The aim of this study was to clinically compare the effect of using a single episode of photodynamic therapy as an adjunct treatment to scaling versus scaling per se within a three-month period in patients with chronic periodontitis in Isfahan. This interventional clinical trial was performed on 20 patients with mild to moderate chronic periodontitis، with pocket depth of 3-6mm and bleeding on probing in at least 3 teeth. Based on split-mouth design، each patient received scaling in one quadrant (as control group) and scaling accompanied by photodynamic therapy in the other one (as the case group). Clinical parameters including pocket depth، clinical attachment loss، bleeding on probing and papillary bleeding index were measured initially and 90 days after treatment. The results were analyzed using Independent T-Test، Paired T-Test، Mann-Whitney and Wilcoxon Tests. Bleeding indices decreased significantly، with a significant difference between two groups. (p<0. 001) Although، the difference of reduction in pocket depth and clinical attachment loss was not significant between two groups (p= 0. 61 and p= 0. 14 respectively)، decrease in these parameters after treatment was significant in each group (P<0. 001). Using a single episode of photodynamic therapy was beneficial for reducing bleeding indices but it did not have extra clinical effects when compared with scaling per se.

Host modulatory therapy (HMT) is a new method that has been used as adjunctive therapy for periodontal diseases. Licorice tablet contains an extract with anti-inflammatory effects. Considering that most patients prefer to take herbal medications. we found it necessary to compare the effects of licorice tablet and doxycycline on chronic periodontitis. In this interventional clinical trial study, 45 patients with mild to moderate chronic periodontitis were selected. Plaque Index (PI), Pocket Depth (PD), Clinical Attachment Loss (CAL) and Bleeding on Probing (BOP) were recorded for all periodontal patients. Then scaling and root planning was done and patients were divided into three groups.In the first group, a 20mg doxycycline capsule was given to each patient daily, the second group was given a 490mg licorice tablet per day and the third group was given a placebo capsule per day. After 6 weeks, all the above-mentioned parameters were recorded again for all patients. Chi-square, paired sample T and one-way ANOVA tests were used for data analysis. The mean of PD, CAL and BOP after treatment reduced significantly within the three groups (P <0.05). The mean difference of PD, CAL and BOP between the two groups of doxycycline and licorice was not significant (P =0.54, 0.74 and 0.64, respectively). licorice decreases clinical periodontal indices of similar to doxycycline in chronic periodontitis.

Gingival recession is defined as exposure of tooth root surface due to apical movement of the gingival margin. Different methods have been used for its treatment. This study was performed to clinically compare the changes observed in periodontal clinical indices between the two methods adopted in treatment of gingival recession: GRT and CTG. In this experimental study, 24 cases of gingival recession were selected in 12 patients who had Miller’s class I and/or II gingival recession in their canines or premolars. Twelve areas were treated with CTG and 12 with GTR method. The studied indices including depth and width of recession, clinical attachment level, probing depth, and width of keratinized gingiva were measured before treatment and 1, 2, 3, and 6 months later. Data were analyzed using Wilcoxon, T-paired and ANOVA statistical tests. Both CTG and GTR methods led to significant decrease in depth of gingival recession (P=0.035), width of recession (p= 0.005), Improvement in clinical attachment level (P=0.05) and width of keratinized tissue (P=0.0001). But no significant difference was noticed between two groups regarding probing depth (P=0.3). although both treatment methods considerably improved the treatment of gingival recession, CTG method was superior to GTR for increasing the width of keratinized tissue and decreasing the clinical attachment level.

Considering the extensive usage of alginate impression materials in dentistry and availability of various brands in the market, quality control of these alginates and assessment of their properties are necessitated. The aim of the present study was to determine the dimensional stability of the impressions made by Golchay Iranian alginate and Bayer German alginate (as the standard) after being stored in moist environment for 0, 12 and 60 minutes. In this in-vitro experimental study, 60 impressions were taken from a mandibular acrylic model using Bayer and Golchay alginate materials (30 samples of each material). Impressions were stored 0, 12 and 60 minutes in moist condition (10 specimens in each group) and were poured using stone gypsum. A digital caliper with the accuracy of 0.01 mm was used to measure the mesiodistal dimension, occlusogingival height and inter-arch distance of the gypsum casts. Values of these three dimension variables for two alginates within each time span were analyzed using one-way ANOVA and student's t-test (significance level was set at 0.05). 2-way ANOVA test was used to evaluate the effect of time, alginate type and the interaction between these two variables. There was no significant statistical difference between samples of Golchay and Bayer alginates regarding mesiodistal dimension, occlusogingival height and inter-arch Distance(P>0.06); moreover, the dimensional stability of the impressions made with each alginate were the same after being stored in moist environment for 0, 12, and 60 minutes (P>0.05). It seems that impressions made with Golchay and Bayer alginates have similar dimensional changes over time and in moist environment.

Loss of bond strength is the most common reason for failure of fiber posts. The aim of this study was to compare the effect of self-adhesive resin cements (Bifix SE, Clearfil SA luting) and self-etch adhesive systems (Panavia F.2, Bifix QM) on bond strength of DT light fiber post. This experimental study was performed on 40 single-rooted human premolars. After being endodontically treated and preparing post spaces for DT light fiber posts, the samples were randomly divided into 4 groups of 10 based on the resin cement type and were submitted to 4000 thermal cycles (5-55c). Then, three 2mm thick segments from coronal, middle and apical thirds of roots were prepared and push out test was performed on them. Then, all root segments were assessed for failure mode using stereomicroscope. From the coronal slices of each group based on dominant failure mode, one slice was randomly selected to be observed under SEM. Data were analyzed using T-test, two way ANOVA and Tukey test. No significant difference was found between the self-adhesive cements and self-etch adhesive system. (p<0.4) The highest and the lowest bond strength values were observed respectively in Bifix SE and Clearfil SA luting, which was statistically significant. (p<0.05) In the studied cements, there was no significant difference between the different regions of root; (p>0.05) However the interaction between the luting cement and different root regions was significant. (p<0.001) The most common failure mode was type 4 (adhesive between the cement and dentin). the type of cement used and interaction between the luting cement and different root regions influenced the bond strength value, but different root regions per se could not influence the bond strength.

Contaminated toothbrush has important role in transmission of infection and disease. The purpose of this study was to evaluate two methods of toothbrush disinfection by sodium hypochlorite 0/1% and microwave on three types of microorganisms: staphylococcus aureus, streptococcus mutans and candida albicans. In this in vitro study, 90 toothbrushes were divided into 9 groups (n=10). Toothbrushes were contaminated by standard suspension of streptococcus mutans, staphylococcus aureus and candida albicans. Then, toothbrushes were disinfected with hypochlorite sodium %0.1 for 10 minutes and with microwave for 1 minute. Afterwards, remained bacteria on surface of toothbrush were cultured and counted. For analyzing Numbers of Colony-Forming Units remained on toothbrush one-way Kruskal-Wallis and Mann-Whitney tests were used. Results of this study showed that significant difference exists among disinfectant effects (p<0.001). Results of Mann-Whitney test showed hypochlorite sodium had more disinfecting effect on Streptococcus mutans and Candida albicans compared with distilled water or microwave (p<0.05).However disinfecting effect of microwave was more than two other disinfectants on Staphylococcus aureus(p<0.05). hypochlorite sodium had more disinfecting effect on Streptococcus mutans and Candida albicans however microwave was more effective on Staphylococcus aureus.

Using disinfectants for cleansing dentures is inevitable. Despite their favorable effect on reducing microorganisms, these chemical materials can cause undesirable effects on the surface of dentures. The aim of this study is to determine the effect of chemical disinfectant solutions on surface roughness of denture base materials. In this experimental in-vitro study, 50 acrylic resin specimens were fabricated from 2 different brands of Meliodent and Acropars. Samples were placed in four groups of solutions (sodium hypochlorite 0.5%, vinegar 2.5%, sodium bicarbonate 5% and Corega tabs). Control group was placed in normal tap water. Samples were evaluated for the initial and secondary surface roughness. One specimen from each group was coated in PVD procedure and was assessed with SEM. Data were analyzed using ANOVA and Post-hoc tests and multiple comparisons. The initial measurements revealed no significant difference between two acrylic materials regarding the studied features (P<0.4). The highest surface roughness in Meliodent group was observed in 0.5% sodium hypochlorite, which was significantly higher than other solutions (P<0.05). In Acropars group, the highest surface roughness was caused by 2.5% vinegar, which was significantly higher than other solutions (P<0.05). Corega tabs presented the least amount of surface roughness on both acrylic resin specimens (P<0.01). Results showed that the effect of disinfectant solutions on surface roughness of Meliodent acrylic is higher than Acropars and the least destructive effect was for Corega tabs. Usage of chlorinated solutions for disinfecting Meliodent acrylic and acidic solutions for Acropars is not recommended.

Discoloration of composite restorations over time is among common factors causing their replacement, which weakens the tooth structure and causes pulpal injury. Since tea is a common drink among Iranians, the current study aimed to evaluate the discoloration effect of tea on Kalore and Gradia composite resins. This experimental study was performed on 20 disc-shaped specimens of two composites, Kalore and Gradia. Ten specimens of each composite type with subgroups of 5 were stored in tea and distilled water for 72 Hours. Color measurements were obtained using Spectrophotometer (Minolta, Japan) before and after immersion in solutions. Final spectrophotometry was done after polishing. The results were analyzed using Kruskal-Wallis test. The discoloration value of both composites increased significantly after being immersed in tea (P<0.001). Discoloration in Kalore was higher than Gradia (P<0.014); and amount of discoloration was clinically unacceptable for both composites. (ΔE >3/3) After final polishing of the samples kept in tea, amount of discoloration decreased for both composites (P<0.001) and (P=0.002) respectively; this reduction was more prominent in Kalore (P=0.008). Nonetheless, discoloration value was yet clinically unacceptable. Immersing the composites in tea caused clinically unacceptable amount of discoloration in both Gradia and Kalore and polishing had more corrective effect on Kalore.

Oral hygiene instructions appear to be ineffective in children who lack adequate motor skills for efficient tooth brushing. This will result in development of caries and periodontal disease. This study sought to assess the tooth brushing skills and the role of related factors in 5-6 year old children in Tehran, Iran. This cross-sectional study was conducted on 680 five and six year-old children including 240 girls and 440 boys. The psychomotor skills of the hands and feet were tested in children and their tooth brushing skill was evaluated using 7 criteria. Other related factors were also assessed. Chi square test was applied to assess the correlation of tooth brushing skill with age of children and related factors. Of all children, 21.1% possessed the required tooth brushing skills while 78.9% did not; 41% of those who did not and 16% of those who did have the tooth brushing skills, did not have psychomotor skills in hands and feet in their age group (P<0.001). Significant correlations were found between tooth brushing skills of children (P<0.09) and place of residence in the city (P<0.07). Lack of tooth brushing skills in children who otherwise have adequately acquired other psychomotor skills related to their age group indicates the complexity of tooth brushing technique for children. Parental supervision is strongly recommended for tooth brushing in this age group.

Various kinds of cancer can negatively affect the quality of life in patients and can indirectly affect the therapeutic results. The current study was enrolled to assess the quality of life in patients with oral squamous cell carcinoma and identify the associated factors to be used for improving the quality of life in patients. This was done on patients referring to Imam Khomeini Cancer Institute, 2012-13. In this descriptive research, 100 patients with OSCC were enrolled 3 months after the end of diagnostic and therapeutic stages when they were in follow-up stage. They were interviewed using EORTC QLQ- H&N35 questionnaire which its validity and reliability was affirmed by Cronbach’s α=0.858. The questionnaire consisted of 35 questions concerning 8 indices (pain, swallowing status, sense of taste, speech, feeling of malaise, social communication, eating in public and sexual desire). At the same time, patients were interviewed and the clinico-demographic characteristics form was completed for each of them. Then, the relation between these indices of quality of life and the studied variables was assessed using Mann-Whitney U-test and Kruskal-Wallis test. As the stage of illness advanced, the quality of life declined in most factors (P<0.05). Women were found to have lower quality of life than men regarding swallowing status, pain, and feeling of malaise (P=0.01). The patients who had OSCC on tongue, lips and buccal mucosa had lower quality of life in terms of swallowing and speaking (P=0.004 and 0.005, respectively). The type of treatment affected the indices of swallowing and feeling of malaise. (P=0.04 and 0.007, respectively). It seems that the site of tumor and the type of treatment play role in reducing the quality of life of patients with OSCC; but advancement in stage of illness was found to be the most important index in decreasing the quality of life.