مجله تحقیق در علوم دندانپزشکی
سال ششم شماره 3 (پیاپی 21، پاییز 1388)

The quality pertaining to the depth and duration of local anesthesia in the primary issue of concern in invasive dental procedure. Profound pulpal anesthesia is necessity for successful dental procedures and failure occurs most often with the interior alveolar nerve block. Positive effects of periods combined with lidocaine has been documented in dentistry, however, no objective study has so far evaluated the effect of lidocaine with and without the effect of fentanyle. Therefore the aim of this study was to evaluate the anesthetic efficacy of using fentanyle with lidocaine in depth and duration of pulpal anesthesia in human inferior alveolar nerve block with pulp tester. This cross over double blind randomized controlled Trial consisted of 19 subjects rating from 19-29 years of age. Each subject was injected with following anesthetics in two separate sections. A: 1.8 ml lidocaine 2% with 1: 80000 epinephrine+40 μg fentanyl (0.8 ml) B: 1.8 ml lidocaine 2% with 1:80000 epinephrine +0.9% saline(0.8 ml) An electric pulp tester was used to test the anesthetic depth of the first molar, canine and lateral incisor in 3 minutes with 60 minutes, interval. If a degree of 80 was consecutively detected 2 times within 15 minutes and maintained for 60 minutes, the anesthesia was regarded successful. combining fentanyl with lidocaine 2% (1:80000 epi) has no significant effect in obtaining profound pulpal anesthesia. There was no significant difference between the two groups in terms of level of pain, onset on anesthesia in the pulp and lower lip, adequacy of anesthesia in a specific tooth and duration of anesthesia (P<0.2).

The biomechanics of implant-retained overdenture can lead to different resorption patterns in the posterior regions of each arch. Two of the most commonly used attachment systems for these type of prostheses are Bar/clip and Ball with different biomechanical properties. The aim of the present study was to compare two types of implant-retained overdenture attachments on the stresses introduced to the mandibular posterior residual ridge by means of 3D Finite Element Method. This experimental study performed with Ansys software. The basic model was generated from data provided by a CT-scan of edentulous patient. Two root form implants were placed in inter foramen region of the mandible. Models were used in order to simulate two situations: In group A, model represented an edentulous mandible supporting an over denture retained by two-splinted implants connected with Bar/clip system while in group B, model simulated an edentulous mandible supporting an overdenture retained by two solitary implants with Ball attachments. The occlusal load of maxillary complete denture was introduced in two directions for each group: vertical load as in centric occlusion, and oblique load as in working lateral excursion. The amount of stress introduced by over denture using Bar attachment was higher in centric occlusion and working lateral excursion. If the only determining factor for choosing the attachment system was the amount of stress introduced to the mandibular posterior ridge, then the Ball system would be the attachment of choice.

proper radiographic evaluation of maxillary and mandibular ridge is needed for assessment of implant site measurements and presurgical treatment planning of implants. The purpose of this study was to access the accuracy of Carnex Tome ® digital in measurements of jaw bore width prior to implant placement. This descriptive study was carried out on 28 implant sites. the impressions were made and future implant sites were marked. The bone width measurements 2mm below the alveolar crest was first obtained on the tomogram of the Carnex Tome and then clinically with a bone gauge during the surgery. Data were statistically analyzed by T - test. Means bone width was found to be 3.44 0.22 mm in standard surgical method (surgery) and 3.45 0.34 mm in tomography. The mean difference between the two methods was found to be 0.19 mm, which was not statistically significant (p<0.4). The tomogram of Carnex Tome Digital is accurate and there is no significant difference between tomography and clinical measurement during surgery.

Over there past few years, the use of fiber reinforced composites has increased in dentistry. The type of fiber used for reinforcement plays an important role in the structural strength of composites. This in vitro study compares the fracture resistance of posterior reinforced composite inlay bridges with two different fiber types.

This experimental, in vitro study was performed on 20 FRC bridges which replaced maxillary second premolars. The abutment teeth were prepared with proximal box design and the samples were divided in to two groups of 10 (n=10). For the first group polyethylene fiber reinforced composites (Fiber span/ NSI/ Australia) were used directly. In second group pre impregnated glass fiber (INTERLIG/ Angelus/ Brazil) were applied the same. After thermo cycling process (5000 cycles, 5°c / 55°c, dwell time 30s, interval 2s) fracture testing was performed in a universal testing machine (Zwick/ Roell/ Germany, 1 mm/ min) applying direct vertical force to the center of the pontic. The One Sample Kolmogorov Smirnov Test showed a normal distribution. Data analysis was done using independent sample T-test.

The mean fracture strength and the standard deviation of the FRC Inlay Bridge was 469± 247 N for polyethylene fiber group and 541± 206 N for glass fiber group. The result of Independent Sample Test was not statistically significant (P= 0.491). The most failure mode observed, was crack and fracture on the surface of FPDs in distal part of the pontics. Frameworks remained with no damage in all samples. There was no stateside difference between two groups of FPDs.

Direct application of each fiber reinforced composite (glass or polyethylene fiber) with the same architecture (Braided) of fibers is comparable in posterior region of maxilla so the structural design of the fiber is more important than the fiber type itself, in fracture resistance of FPDs.

Considering the importance of the etiology of the periodontal problems especially in relation with fixed appliances, this investigation was undertaken to evaluate any possible relationship of fixed appliances and periodontal problems. This research was carried out by Historical Cohort design. In this investigation 30 girls under fixed appliance orthodontic Treatment, who had at least six months of appliance wear, and 30 girls of the same age group in the same school as Control group were examined. The girls in the two groups had no history of trauma and the control group had no previous orthodontic treatment the periodontal condition of both groups was examined and recorded by a Periodontologist. In terms of bleeding index, periodontal enlargement which was classified into grades I, II, III and gingival recession. In the grades of0، I, II, III and gingival recession.، Gingival bleeding, enlargement and recession was evaluated statistically by Exact fisher test. The age was matched between two groups (15. 1+1. 5 &14. 7+2. 4 years). Gingival Bleeding was 50% and 76/7% in the Control and Case group respectively (p>0/3). Gingival Recession was 3/3% and 0% in the control and case group respectively. (p>0/9). Gingival enlargement with grade 2 and more was 13/3% and 46/4% in Control and Case group respectively (p>0/005). It seems that use of fixed appliances for orthodontic Treatment increases the incidence and possibility of gingival bleeding and enlargement. Proper preventive steps should be tolcan to avoid such complications

One of the most prevalent problems in dental implant placement is the existence of narrow edentulous ridge. Therefore, the aim of this study was to evaluate the short term clinical and radiographic parameters after implantation in narrow ridges using the expander drills in referred patients to a private office in Tehran in 1387. In this descriptive study, 15 implants were placed in the edentulous ridge of 8 patients. (Bone width < 6mm). To increase the width of the ridge, the expansion drill (BTI Spain Company) with 50 rpm and irrigation was used. When needed a graft and membrane were placed. The amount of bone loss and mobility of implants were evaluated with periotest after 4 months. A total of 15 implants were placed in 8 patients (mean age: 49.7±14). Following the healing period was passed for all cases, no radiolucencie were found around the fixtures and no pain or infection was reported. The amount of bone resorption at the crest area was reported to be 0.2±0.4 mm. The mean of PTV was -2.5±0.9. Using the expander drill is an appropriate method for increasing the Buccolingual width of the ridge and it is recommended for atrophic ridges.

Osteoprotegrin (OPG), a member of the TNF receptor family, is a soluble molecule which inhibits bone resorption by binding to its ligand RANKL. The aim of this investigation was to determine the level of OPG in peri-implant crevicular fluid (PICF) and the possible relationship between its presences with the peri-implant tissues status. Design of this article was case-control. 13 implants with symptoms of peri-implantitis, 14 implants with symptoms of peri-implant mucositis & 13 healthy implants were analyzed. Filter paper strips were used to collect PICF for 30 seconds in the base of the pocket from each implant, therefore 80 samples were collected. PICF level of SRANKL was determined by ELISA. Spearman’s correlation was used to relate biochemical data & clinical parameters. Mean OPG concentration in healthy implants was (19.33±1.73), in peri-implant mucositis group was (19.14±1.31) & in peri-implantitis group was (19.13±1.14). However, there was not a significant difference in OPG concentration between groups (P=0.85).OPG concentration showed no significant difference when the healthy implants were compared to the diseased ones (peri-implant mucositis & peri-implantitis) (P=0.57). There was no correlation between OPG concentration & clinical parameters (PPD, GI, PI) when the samples were compared as a whole. However, comparing the groups separately, there was a correlation between PI & OPG concentration within the samples of peri-implantitis group.(P=0.026) As we hypothesized OPG concentration in healthy implants is higher in comparison to the diseased ones. As the disease progresses OPG level decreases. Thus, it is reasonable to consider OPG concentration in PICF as a strong marker of the condition of peri-implant tissues.

Achieving the ways to have a proper diagnosis in detection of secondary caries is very important. Therefore the aim of this study was to evaluate the accuracy of bite wing radiography in diagnosis of secondary caries in posterior teeth in CL. II Amalgam & Composite restorations. (In vitro) This experimental study was performed on 60 sound extracted human teeth and 120 Standard Cl II cavities were created in mesial & distal surfaces of teeth and the teeth were randomly divided Into six group. in four of the groups(n=40),a 1.0 mm cavity was prepared in the gingival and axial riml of the restoration. No lesions were created in 2 group, The control group. The teeth were restorated with Amalgam and Composite. The radiography was made with conventional bite wing technique. Three expert observers evaluated the bitewing radiographs for the presence or absence of secondary caries. Finally, all of the data was recorded on a special table. Statistical analyzes showed: for Cl II Amalgam a sensitivity was(55%),Specificity was (100%), positive Predictive value was (100%),Negative Predictive Value was (67%) and accuracy was(76%) and In Cl II Composite restoration was reported as (71%), (75%), (74/5%), (72%), (73%). this study showed an acceptable sensitivity (72%)of diagnosis of secondary caries in Cl II Amalgam & composite in comparison restorations applying bitewing technique.

Regarding the high rate of dental caries and its known consequences and the necessary to have disease etiologic studies and in order to determine any relation between fluoride amounts of drinkable water, we performed the research for DMFT amount in rural of Behshahr city in 2006. We performed our research by historical cohort on 165 persons in case group in different areas with lower amount of fluoride than 0.4 ppm, and 164 persons in control group in different areas with natural fluoride between 0.6-1.2 ppm that, the persons of both groups were similar to the point of the height, age, gender, position of father, residing period in place, literacy level and wideness of family and our sampling method based up on the goal. Their DMFT condition was assessed according to determined standard and the role of low fluoride in drinking water with exposing more than 5 teeth and chi-square statistic. The amount of DMFT in case zones was equal to 11/7 +-7/9 and 8/4+-6/6 in control group (P<0/0005). The people of case zones had 83% of DMFT above 5 and those in control group 65% (p<0/0005). R.R of low fluoride in water has been 1.3 times more than control, with exposing DMFT of over 5 in case people. The risk relating to the high dental caries for subjects with low fluoride of drinking water has been 18% as well (R.R=1/3). It seems that the low amount of fluoride of drinkable water may increase the chance of DMFT we may recommend any experimental researches in order to determine any effects of adding fluoride to water in order to prevent from DMFT.

Regarding the high rate of caries prevalence and the lack of enough treatment supplies in the society as well as the significant role played by the proper amount of fluoride in water supplies in dental health. The goal of this study was to determine the amount of fluoride in Sari drinking water in spring of 2009. This descriptive research was performed on water samples of all drinking water sources in the city of Sari. The sampling process was conduct at nearest home surrounding each source. All samples were delivered to Tehran dental school IA university quality control laboratories. The amount of each samples fluoride was determined as less than normal, normal, and more than normal using potentiometer method. This study was performed on 36 samples. The total volume of Sari water source was two hundred twenty six thousand and two hundred cubic meters and the total amount of fluoride in Sari drinking water was 0.35±0.15 ppm. The amount of fluoride in 100 % of the total drinking water was less than standardized level. Unfortunately the amount of fluoride in Sari drinking water is significantly less than the standardized level.