مجله تحقیق در علوم دندانپزشکی
سال هشتم شماره 4 (پیاپی 30، زمستان 1390)

Considering the prevalence of skeletal open bite and existing controversies around the relation between pharyngeal dimensions and dentofacial as well as craniofacial structures, the aim of this study was to investigate the pharyngeal dimensions in CLII division I subjects with and without skeletal open bite malocclusion. This case control, double blind study was based on paraclinical data obtained through close analysis of files, cepholograms and study models. A total of 40 subjects, including 19 male and 21 females (mean age: 65.14± 1.53 yrs) were selected based on the maxillary-mandibular plan angle, SN-Mandibular plan angle, Y-Axis and Tarabak Index. The study group was divided into two groups. The case group included 20 subjects with skeletal open bite and the control group consisted of 20 subjects without skeletal open bite. The pharyngeal dimensions including nasopharyngeal, oropharyngeal and Hypopharyngel, depths were measured. The length of the airway and the distance between the hyoid bone and the mandibular plane were also recorded. Data was analyzed by T-test. There was no significant difference between the two groups in terms of Nasopharyngeal, Oropharyngeal and Hypopharyngeal dimensions. Significant statistical difference was found between the length of the airway in the case group (62.4± 3.78) and the control group (15.75± 3.76) (p<0.03). There was also statistically significant difference between the distance of Hyoid bone to mandibular plane in the case group (15.75± 3.76) and the control group (12.1± 3.64) (p<0.003). There was an increase in both variables in the case group. The Nosopharyngeal, Oropharyngeal and Hypopharyngeal depths are not associated with skeletal open bite The length of the airway and the Hyoidbone- Mandibular plane distance could affect the growth pattern. Pharyngeal dimensions or respiration patterns have no effect on the growth pattern.

: Dimensional changes of impression materials cause distortion of the cast with negative impact on the outcomes of prosthodontics treatments. There is less evidence about accuracy of the domestic alginate impression materials.The aim of this study was to compare the dimensional changes of Ariadent and Bayer alginate impression materials. Materials and Methods In this experimental study, seventeen casts were made from master model by a cast metallic special tray, using Ariadent (case) and Bayer (control) alginates. Small and large diameter, height and distance of two dies were measured by a digital measuring instruments. Data were collected and analyzed by Paired T –Test, and MannWhittney for the two groups and master model. The difference between the size of small and large diameter, height, and distance of centers of two dies made from Bayer alginate was 209.2 ± 185.6, 345.5 ± 230.7, 219.9 ± 213.1. and 328± 478.7 and for the Ariadent alginate was 198.3 ± 215.5, 342.8± 227.3, 336.7± 280.9, and 281.9± 336.7 microns respectively. These differences were significant with respect to master model (P<0.0005). The changes of measured dimensions within two groups were not significant statistically (P <0.5). Both impression materials have significant dimensional changes which can not be used in fixed prosthodontics; however they can be used in removable prosthodontics with adherence to the principles of standard guidelines.

Advances in Science and considerable attention to health issues has led to an increase in use of medications. In recent years, plant extracts have been the focus of attention due to less side effects and higher cost effectiveness compared to chemical therapeutic products. The aim of this invitro study was to compare the inhibitory effects of plant extracts containing thyme, clove and cinnamon with nystatin on candida albicans. This experimental study assessed the antimicrobial effect of 3 plant extracts on Candida Albicans. Thyme, Cinnamon and Clove extracts were selected based on previous researches and traditional use. C.Albicans was cultured on sabouraud dexterose agar containing chloramphenicol. On each plate, one plant extract disc, one nystatin disc (aspositive control), one methanol and one blank disc (as negative controls) were placed. The mean diameter of non-growth halo around each plant extract was compared with the mean diameter of non-growth halo of positive control discs after 24 hours.Data analysis was done by ANOVA statistical test. There was significant different between the diameter of non-growth halo around the plant extracts and nystation discs. (P<0.05). The diameter of non-growth halo in cinnamon discs (31/3) was smaller than that for nystatin discs (32/6) (p<0.000). Non-growth halo in discs containing Clove (27/4) and Thyme (13) were also smaller than Nystatin discs (32/6) (p<0.000). Thyme, Clove and Cinnamon exhibited antifungal effects on C. Albincans.

Floss and tooth brush may not always be applicable anywhere in a world of mechanization and rapid transit. Therefore an alternative way of oral care have always been a subject of study by dentists. Sugar free gums are cited as an effective solution in this field by some texts. The aim of this study was to determine the effect of chewing xylitol gum on reduction of plaque regrowth at the buccal, lingual, proximal and occlusal surfaces of teeth. Twenty healthy female dental students with optimal oral health participated in this randomized, single-blind, crossover 3-day plaque regrowth study. From a zero plaque score on day 1, (through brushing and polishing) half the subjects suspended oral hygiene measures while half of them were asked to chew Zylitol gum. for 30 min 4 times per day. On fourth day, subjects were scored for plaque using disclosing agent on buccal, lingual and urestored occlusal surfaces.The same process was repeated with shifting of two groups after 4 days of normal dental hygiene period. The indices used in this study were, M.Addy for occlusal surface and Oleary for smooth surfaces. Data were analyzed using Spss software, variance & paired T-Tests. The difference in scored plaque of occlusal, Buccal and lingual, surfaces of teeth among two groups according to chewing Xylitol Gum were significant, (P=0.01), (P=0.02),(P=0.01) respectively there is not significant reduction in proximal surfaces, according to Chewing Gum (P=0.05). chewing Xylitol containing gum can reduce plaque accumulation on occlusal, buccal and lingual surfaces; but it has no effect on proximal surfaces.

Despite evidence of excellent results of implant therapy, peri-implant diseases do occur. The aim of this clinical study is to evaluate the efficacy of the closed surface scaling on clinical indices in the treatment of Peri-Implant Diseases. 10 subjects with 15 different sites of peri-implant diseases (including peri-implantitis and peri-implant mucositis) were selected. The sites were treated with closed surface scaling alone. Clinical indices including; Clinical Attachment Loss (CAL), Probing Pocket Depth (PPD), Bleeding On Probing (BOP), Gingival Index (GI), were evaluated at baseline and 1.5 and 3 months following therapy. Data was analyzed using Wilcoxon signed-rank test. Out of female and male with age of 52.8±7.33, the mean CAL changed from 7.16 ± 1.4 at baseline to 7.17 ± 1.4 at 1.5 months after treatment and 7.18 ± 1.5 at 3 months after treatment. Also the mean PPD changed from 5.08 ± 1.47 at baseline to 5.09 ± 1.5 at 1.5 months after treatment and 5.08 ± 1.5 at 3 months after treatment. There were no statistically significant differences in mean CAL and mean PPD (p < 0. 9). Bleeding scores and GI were not significantly reduced, at any time point (p < 0. 9). This study demonstrated that closed surface scaling alone, is insufficient for the treatment of peri-implant diseases and the adjunctive use of antimicrobial agents is recommended.

Radiographic diagnosis of external root resorption is one of the basic problems in endodontics. This lesion results in loss of tooth structure and its diagnosis in early stages will result in tooth preservation. The purpose of this in vitro study was comparison of the diagnostic accuracy of conventional and digital radiography in detection of simulated external root resorption cavities. In this diagnostic study 40 maxillary and mandibular anterior teeth which had no external root resorption in initial radiographs were put into the human models in order to simulate the condition of oral cavity. Radiographs of each tooth were taken in an orthoradial aspect using conventional film and a digital sensor. Cavities were created by medium round burs (ISO size 009) in 0.9 mm diameter and 0.9 mm depth in the labial wall of the coronal third of the root surface of each tooth. Three periapical radiographs of each tooth were taken in an orthoradial and mesioradial and distoradial aspect using conventional film and a digital sensor. Two endodontists and one radiologist evaluated the radiographs. Diagnostic accuracy of digital and conventional radiographs were evaluated by SPSS and x2 test. A large number of cavities were detected by the digital method compared to the conventional method. There was significant difference in diagnostic quality between conventional and digital method for distoradial, orthoradial and mesioradial aspects (P<0.05). Tests revealed that sensitivity,specifity,PPV(Positive Predictive Value), NPV(Negative Predictive Value) and accuracy were significantly different in comparison of digital and conventional radiographs(p<0.05). The results of this study suggest that the digital radiographic method is more sensitive than conventional radiography in detection of simulated external root resorption cavities.

Clinical diagnosis of oral lesions is a difficult task. Correlation between clinical and microscopic diagnosis demonstrates correct viewpoint between clinician and pathologist.Nowadays use of radiography, biopsy and microscopic survey are auxiliary ways for definite diagnosis of lesions. The purpose of this study was to evaluate the correlation between clinical and microscopic diagnosis of oral lesions in patients referred to oral pathology department of Islamic Azad Dentistry University of Tehran from 2005 to 2009. This descriptive study was done based on existing data. Variants of study including age& sex of patient, location of lesion (central, peripheral), clinical diagnosis (1st diagnosis) and microscopic diagnosis & clinician's degree (general- specialist) was recorded. Statistical analysis was done with SPSS13 using concordance coefficient and statistic model "binary logistic regression". Out of 1337 cases 238 cases were without clinical diagnosis (21%). Agreement in clinical µscopic diagnosis was found in 683 cases (concordance coefficient %65/1). Concordance coefficients were %52/1 in first clinical diagnosis. The greatest concordance coefficient was observed in diagnosis of epulis fissuratum, pemphigus vulgaris, papilloma, ranula. Non specific ulcer, benign epithelial hyperplasia, leukoplakia, myxoma and Keratoacanthoma revealed the lowest coefficient. Sex age, referral clinician, location of lesion & type of lesions did not have significant effect on concordance coefficient. The highest concordance coefficient was obtained from oral and maxillofacial surgeons. Absence of a clinical diagnosis in a lot of the cases demonstrates that clinicians neglect the value of clinical data on the definite diagnosis.