مجله دانشکده دندان پزشکی اصفهان
سال نهم شماره 1 (پیاپی 36، فروردین و اردیبهشت 1392)

Many efforts have been made to improve Ni-Ti alloy for endodontic use and it has been shown that surface properties and thus cutting efficiency of the rotary files can be improved by processes such as electro-polishing، ion implantation and surface coating. The aim of this study was to evaluate the effect of cryogenic treatment on cutting efficiency of Ni-Ti rotary files. In this in vitro study، 60 Ni-Ti rotary instruments (Hero 642، #25، 0. 04 taper) were selected and divided into 3 groups of 20. In group I no treatment was used. In group II the instruments were subjected to a deep cryogenic treatment in liquid nitrogen pool (-196°C) for 24 hours and after treatment were immediately tested for cutting efficiency. In group III after cryogenic treatment the temperature of the samples was raised slowly to room temperature for 24 hours. A new piece of test equipment was designed and used. The instruments were attached to the testing machine and rotated in Plexiglas samples for 10 seconds in a working length of 16 mm. The depth of grooves and weight loss of Plexiglas were measured after instrumentation. One-way and two-way ANOVA were used to compare the means of cutting efficacy between the three groups at 95% confidence interval. The instruments which were immediately tested for cutting efficiency had significantly more weight loss and deeper grooves (pweight < 0. 001; pgroove = 0. 022)، indicating better cutting efficiency. However، there was no significant differences between group I and group III in cutting efficacy (p weight = 0. 23; p groove = 0. 61). The results of this study showed that the surface properties of Ni-Ti alloy could be improved by the cryogenic treatment for a limited period of time after treatment، increasing the cutting efficiency of Ni-Ti rotary instruments.

It is possible for the CSF to leak during cranial and maxillofacial fractures. At present there is a little information about CSF leakage، use of antibiotics، lumbar drainage and its surgical indications. The aim of this study was to evaluate the frequency of CSF leakage in cranial and maxillofacial fractures.

In this cross-sectional/analytical study، 1278 files of patients with maxillofacial fractures، admitted into the Department of Maxillofacial Surgery in Al-Zahra Hospital، were evaluated and the data were analyzed using descriptive tests.

In this study، of 1278 patients suffering head and maxillofacial fractures، 16 males and one female had CSF leakage; all these cases had skull base fracture، 53% had maxillary fractures، 23. 5% had nasal fractures، 41. 1% had orbital fractures، 58% had mandibular fractures، 23. 5% had frontal fractures and 57. 14% had more than one fracture. Of the patients with CSF leakage 58. 8% had rhinorrhea and 41. 2% otorrhea. Of all these cases، 8، 7 and 2 patients were cured spontaneously، surgically and by lumbar drainage، respectively.

All the patients with skull base fractures exhibited CSF leakage and all had maxillofacial fractures. It is suggested that surgeons take into account the possibility of skull base fractures and CSF leakage during treatment of maxillofacial fractures.

Nowadays the necessity of the existence of a certain width of keratinized gingiva is emphasized upon to maintain periodontal health and prevent soft tissue recession around teeth and dental implants. This study was carried out to compare two gingival graft procedures including connective tissue graft and graft with a combination of collagen sponge with platelet-rich plasma and platelet-rich fibrin to increase the width and thickness of keratinized gingiva.

In this clinical trial 8 patients with bilateral inadequate width (≤ 2 mm) and thickness (≤ 1 mm) of keratinized gingiva on the buccal aspect of single-rooted teeth were selected. On the control side، connective tissue graft and on the test side، graft by combination of stypro+PRP+PRF were performed. After surgery، the measurements were repeated at 1، 2 and 3 months. Data was analyzed by Wilcoxon’s test to compare the 2 groups and Friedman’s test was used for comparisons within each group with SPSS 15 (α = 0. 05).

After 3 months there were no differences between test and control groups in relation to the width of keratinized (p value = 0. 317)، attached gingival (p value = 0. 527)، thickness of the graft (p value = 0. 05) and thickness of the keratinized layer (p value = 1).

It appears the new approach for gingival augmentation used in this study may be a proper substitute for autogenous gingival grafts.

Precise fit between implant components is an important factor for successful implant treatment. The aim of this study was to determine microleakage of Biohorizons، Implantium and Swiss Plus implant systems. In this experimental study، 5 implant fixtures from 3 implant systems were subjected to dye penetration test. One µL of 0. 1% Toluidine blue solution was injected into implant fixtures using an electronic pipette. The corresponding abutments were subsequently screwed onto the implants with a torque of 30 N. Implant‒abutment complexes were placed in 2 mL of distilled water. The amount of leakage of Toluidine blue (TB) was measured by a spectrophotometer at 630 nm at 1-، 3-، 6-، 24-، 48-، 72-، 96-، 144-، 192- and 240-hour intervals after incubation. Calibration curve and a linear equation were obtained by Excel software. Data were analyzed with SPSS 11. 5 using ANOVA (α = 0. 05). In the three implant systems evaluated microleakage was only statistically significant at hours 1 (p value = 0. 01)، 3 (p value = 0. 011) and 6 (p value = 0. 000). Two-by-two comparisons between the implant systems during the first three hours showed the highest microleakage with Swiss Plus and the least microleakage with Implantium systems. However، after the first three hours the differences were not statistically significant between the three implant systems. Among the three implant systems evaluated the least and highest microleakage scores at 1-، 3- and 6-hour intervals were observed with the Implantium and Swiss Plus systems، respectively. All the implant systems exhibited microleakage with time.

Studies have demonstrated the effectiveness of psychological stage-based educational interventions to promote healthy behaviors. This study examined the effectiveness of an educational intervention based on the stages-of-change model in improving oral self-care behaviors among students in Qazvin، Iran. In this randomized controlled study، 160 elementary schoolchildren who were in inactive stages were selected from 8 primary schools using multi-stage sampling approach and were assigned to either the control or the intervention group. Data، including demographic variables، transtheoretical model constructs and the modified plaque index، was collected using a questionnaire before and six months after the intervention. The educational intervention consisted of four 45‒60-minute sessions with a focus on attitude change، self-efficacy promotion and decisional balance change، using images، educational clips and special pamphlets in the intervention group. Data were analyzed with chi-squared test، paired t-test، independent t-test and ANOVA، followed by post hoc Scheffé’s test، Wilcoxon’s test and Mann-Whitney test (α = 0. 05). Before the intervention، none of the subjects were in the action and maintenance stage، while after the educational intervention، 26% of the intervention group subjects moved to active stages and the number of pre-contemplation stage subjects was halved (p value = 0. 0003). Significant improvements were observed in self-efficacy (p value = 0. 0006)، process of change (p value = 0. 002) and decisional balance (p value = 0. 005) in the intervention group. Training based on the stages model was able to significantly decrease the plaque index (p value = 0. 0001) and increase self-reported oral care behavior (p value = 0. 021). Educational intervention based on stages-of-change model can improve oral health-related behaviors، and clinical oral and plaque indexes among students.

It is possible to estimate an individual’s age when the birthday is indefinite by dental eruption stages. At 14‒21 age range only third molars are being developed. Therefore، the aim of this study was to evaluate the relationship between the eruption stages of third molars and chronological age in a group of 14‒21 year-old subjects. In this descriptive–analytical study، carried out during spring and summer 2012 in two clinics of the university، 180 panoramic radiographs of 34 males and 146 females were assessed; the subjects were in the 14‒21 age range. Eruption stages of third molars were divided into 4 stages: 1. no emergence; 2. alveolar eruption; 3. gingival eruption; and 4. complete eruption. Then the relationship between these classifications and chronological age was evaluated separately in relation to sex. Then the relationship was used to predict each subject’s age. Pearson’s correlation test and regression analysis were used for data analysis with SPSS 11. 5 (α= 0. 05). Spearman’s correlation coefficients of teeth 18، 28، 38 and 48 were 0. 621، 0. 659، 0. 659 and 0. 633 in males and 0. 658، 0. 648، 0. 636 and 0. 614 in females، respectively (p value < 0. 001 in all the cases). The mean ages for alveolar، gingival and complete eruptions were 15. 46، 15. 92 and 19. 12 years in males and 16. 03، 18. 02 and 19. 06 years in females، respectively. There is a significant relationship between eruption stages of third molars and chronological age. Evaluation of wisdom teeth separately in relation to sex can be used for estimation of age.

Candida albicans is the most prevalent opportunistic fungus in the oral cavity. To date، the association of various factors with the incidence of candidiasis has been evaluated. Some studies have yielded conflicting results about the association between ABO blood group antigens and candidiasis. The aim of this study was to evaluate the relationship between the mean colony counts of C. albicans in the saliva of healthy subjects and their association with ABO blood antigens. Three hundreds healthy subjects (100 with blood group A، 100 with blood group B and 100 with blood group O) were included in this cross-sectional/analytical study. The unstimulated salivary samples of all the participants were collected by spiting، which were cultured to determine the colony counts in each subject’s saliva. Data were analyzed by SPSS 16 by Kruskal-Wallis test and Pearson’s correlation coefficient. The subjects included 156 males and 144 females، with a mean age of 27. 52 years. The mean colony counts of C. albicans in the O، A and B blood groups were 26. 4، 19. 84 and 21. 23، respectively. The results did not show significant differences between the three blood groups in the mean colony counts of C. albicans. Under the limitations of this study there was no relationship between colony counts and blood types. Further studies are recommended to confirm the effect of ABO blood group (especially blood group O) on susceptibility to candidiasis.

A paramount objective of orthodontic therapy is the improvement of facial esthetics. Thus، it seems worthwhile to outline the common denominators of an esthetic smile. The aim of this study was to determine age and sex effects on the dental esthetic zone during posed smile and tooth display in the natural rest position in adults.

A total of 120 Iranians، from Isfahan، were randomly selected from three age cohorts of 20–25، 35–40 and 50–55، with equal distribution of the subjects. The subjects’ photographs were taken during posed smile and in the natural rest position. In addition a record of full dentition was made. Measurements were carried out and statistical analysis of the data was carried out using correlation analysis، analysis of variance، and post hoc Tukey tests (α = 0. 05).

With aging، maxillary lip line heights decreased significantly in the two situations of rest (p value = 0. 03) and posed smile (p value = 0. 02) to expose the teeth. In older participants، mandibular teeth were displayed only in the rest position (p value < 0. 01) but during posed smile mandibular lip line height and tooth display did not change with age (p value > 0. 05). Women had significantly greater average maxillary lip line height and tooth display than men in the two situations (p value = 0. 03). In contrast، men tended to show more of the mandibular anterior teeth than women at rest (p value < 0. 001). However، there were no significant differences between men and women during smile (p value > 0. 05).

The significant decrease in the upper lip line height and the resultant decrease in tooth display during rest and smiling indicate the significant effects of age on dental esthetic zone in which the differences between sexes are also involved. Therefore، the effect of two factors of age and sex should be included in orthodontic treatment planning.

The clinical success of indirect restorations is influenced by several factors، including selection of a suitable cement. The introduction of adhesive resin systems has led to increased use of bonded all-ceramic restorations. The aim of this study was to review adhesives، particularly adhesive resins and their clinical characteristics، considerations and requirements in an attempt to assist dentists in selecting appropriate adhesive cements in special clinical situations. This review paper used a scientific search for library resources، books and websites of Pubmed and ISI Web of Science in connection with articles published up to 2012 on classification and types of dental cements، their clinical applications، the mechanism of curing resin cements، bonding mechanisms and biocompatibility، adhesion principles، current issues in the field of fiber posts in root canal cementation and surface preparation of dental ceramics. In addition، a variety of surface preparation methods available for fiber posts and different dental ceramics were discussed. New materials are constantly marketed by manufacturers، making it difficult to select appropriate cements and to teach cement application. Selection of an appropriate cement is very important because the dentist will be able to apply a suitable surface treatment on the cemented surface. When optimal compressive strength، minimal film thickness and low solubility in water are desirable، conventional cement materials are desirable; however، these cements require ideal tooth surface preparation. Conventional cements are used for porcelains that are not etchable. On the other hand، due to the superior physical properties of resin cements and higher aesthetics compared to conventional cements، they are good choices for cementation of metal-free restorations.

Papillon-Lefèvre syndrome is a rare autosomal recessive disorder. This syndrome is characterized by palmoplantar hyperkeratosis، severe periodontal destruction and premature loss of primary and permanent teeth. The teeth erupt normally but due to the severe alveolar bone loss in both deciduous and permanent dentitions teeth are exfoliated within two or three years after eruption and by the age of 15 or 17 patients are usually edentulous. The identified genetic defect in this syndrome involves a mutation in the gene encoding cathepsin C. An increased susceptibility to infection has also been reported in patient with this syndrome. Case Report: A 15-year-old girl was referred to the dental clinic، complaining of the mobility of permanent teeth. The patient had lost all the permanent teeth except for teeth 13، 14، 17، 23، 27، 37، 43، 44 and 47. The third molars were impacted. The patient had advanced periodontal disease and all the teeth had severe mobility. There was hyperkeratosis at the palms and soles. She did not report a history of recurrent skin infections and liver abscesses. Complete blood count and liver tests were within the normal limits. Due to periodontal disease the dentists are often the first to diagnose this syndrome. Early diagnosis of Papillon-Lefèvre syndrome can help preserve the permanent teeth by early institution of treatment، using a multidisciplinary approach. Dental treatment includes extraction of all deciduous teeth، professional prophylaxis، conventional periodontal therapy، systemic antibiotics، oral retinoids، complete dentures and implants.