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Background and Aims: To be successful in root canal therapy, the dentists must be aware of the possible variation in the root canal and should know not only the natural anatomy of the pulp, but also a variety of possible morphologies. Frst of all, the dentists should be familiar with the possible anatomy of the root canal and then with the extraction of organic tissue from pulp chamber and root canal, increasing the chances of treatment success. Therefore, in this study, we decided to investigate the internal anatomy of root canals in the maxillary permanent molar teeth in Khoy city. Materials and Methods: In this in vitro study, 100 extracted human molars in Khoy city in West Azerbaijan province were collected. In all teeth, the access cavities were prepared, then they were decalcified and colored with India ink and evaluated by clearing technique. Data were collected based on Vertucci's classification which entered into SPSS23 software. The descriptive statistics in the form of numbers and percentages in tables and graphs were used to analyze the data. Results: The most common type observed in the mesiobuccal root of the first molars was type IV by 44%, in distobuccal root was type I by 92%, and in palatal root was type I by 94%. Also, in the mesiobuccal root of the second molars, the most common type was type I by 70%, in distobuccal root was type I by 94%, and in palatal root was type I by 96%. Conclusion: The mesiobuccal root of the first molar had the most variation in the internal anatomy. Also, the most common type of Vertucci in the mesiobuccal root of first molar was type IV and in the other roots of the first and second molar teeth was type I. [ABSTRACT FROM AUTHOR]

Background and Aim: an air void between the restoration and tooth because of Variable Environmental Pressure can lead to pulpal pain or fracture of the tooth or restoration. Materials and Methods: 60 molar teeth divided to 2 groups. Preparation in Group A was a Cl V cavity in wich the Gingival margin was 1mm under CEJ while the occlusal margin was in enamel. For Group B, we followed the same procedure plus a 0.5mm bevel with 45 degree angle in the enamel margin. Group A was filled with composite inlays of Filtek Z250 (3M ESPE, St. Paul, MN, USA). Group B was restored directly by the same composite.Each group were divided into control and case groups. The case specimens were put into 96 cycle pressure for 0 to 5 atm. Then the specimens were put in distilled water and were kept in silver nitrate solution. After washing them with water, they put in radiographic developer solution under fluorescent light. Finally, they were cut by a diamond disc and the microleakage were studied under a stereomicroscope with 20X magnification. Data was evaluated using two-way nonparametric model Results: There was no significant difference between direct and indirect restorations, both in fixed and variable pressures in the occlusal walls. P=0.1 Besides, in both direct and indirect groups there was a significant difference in gingival wall between fixed and variable pressure, in a way that in fixed pressure, there was less microleakage. (P=0.000) Conclusion: Changing in environmental pressure increase the microleakage in direct and indirect restorations. [ABSTRACT FROM AUTHOR]

Background and Aims: The purpose of this study is to evaluate the effect of the type of zirconia (multilayer or monochrome) on the marginal and internal fit of a three-unit bridge. Material and Methods: In a maxillary model, the first premolar and first molar were prepared to receive 3-unit zirconia fixed dental prostheses and then scanned. Each scan was used to make two bridges (one with multi-layer and the other with monochrome zirconia). With Exocad software, the bridge was designed and then milled. The bridges milled in the previous stage were evaluated and compared with the replica method in terms of internal and marginal fit. For statistical analysis, an independent t-test was used to evaluate marginal, cervical, and axial fit, and the Mann-Whitney test was used to evaluate occlusal fit. (P = 0.05) Result: The average marginal and cervical gaps in monochrome zirconia were 65.30±20.00 and 72.42 ±10.11 micrometers, respectively, and in multi-layer zirconia were 70.76±14.71 and 78.74±11.91 micrometers, and this difference was not statistically significant (P>0.05). The average axial and occlusal gaps in monochrome zirconia were 102.5±10.70 and 118.9±18.52 micrometers respectively and in multilayer zirconia 114.8±18.88 and 141.6±29.88 micrometers, this difference was statistically significant and the average gap in monochrome zirconia was less than multilayer zirconia (P<0.05). Conclusion: Monochrome zirconia restorations show similar marginal and internal fit compared to multilayer zirconia restorations. Although the occlusal and axial gap in multi-layer zirconia is more than in monochrome zirconia, it is within the clinically acceptable range. Multilayer zirconia is generally clinically usable. [ABSTRACT FROM AUTHOR]

Background and Aims: One of the concerns of dentists is selecting a suitable brand of stainless steel crowns with maximum dimensional adaptation with primary teeth. The aim of this study was to compare the primary molar crown dimensions with that of two brands of stainless steel crowns (SSCs) in a sample of Iranian children. Materials and Methods: In this study, 130 eligible children between 3 and 12 years (66 boys, 64 girls) were selected. After recording the demographic information, the mesiodistal, buccolingual and occluso-gingival dimensions of first (D) and second (E) primary molars were measured on dental casts and compared with the dimensions of KTR (MeiMeiMinBenjing, Benjing, China) and Shinghung (Shinhungcompany, Seoul, South Korea) SSCs. Data were assessed using chi-square test and Pearson correlation coefficient. P<0.05 was considered statistically significant. Results: In this study, the most dimension matching of the teeth with that of SSCs were observed mesiodistally in upper D and lower D, buccolingualy in the upper D and lower D, and occlusogingivaly in upper D and lower E. The most cases of mismatch in the mesiodistal dimensions of the teeth with that of SSCs were observed in the lower E and upper D. Also, the most cases of mismatch in the buccolingual dimension were found for upper E and lower E. Conclusion: Both SSCs brands in this study showed significant dimensional adaptation with the primary teeth in Iranian children. The most dimensional adaptation was between KTR SSCs and maxillary primary molars, and between Shinhung SSCs and mandibular primary molars. [ABSTRACT FROM AUTHOR]

Background and Aims: Dry socket is one of the most common post-tooth-extraction complications. The aim of this study was to investigate the relationship between some of the predisposing factors of dry socket and this complication in all maxillary and mandibular molars and evaluation of its incidence. Furthermore, the two jaws were compared. Materials and Methods: In this descriptive-analytical cross-sectional study, 150 patients were examined in 2020 in the city of Zahedan. A questionnaire consisting of two sections was designed: In the first section age, gender, systemic disease, smoking status, contraceptive pill consumption, and antibiotic consumption were investigated. In the second section, data related to the difficulty of surgery based on the duration of surgery and the number of local anesthetic cartridges that were administered were collected. Then, the collected data were analyzed by Chi-square and KruskalWallis tests. Results: The incidence of dry socket was 25.3%. The frequency of dry socket was significantly relevant to smoking, oral contraceptive consumption, difficulty of the surgery, and the number of local anesthetic cartridges that were administered (P≤0.05). Age, gender, controlled systemic disorder, and systemic antibiotic usage for two weeks prior to surgery revealed no significant associations with dry socket (P>0.05). Furthermore, the frequency of dry socket in maxillary and mandibular jaws had a significant difference according to smoking status, difficulty of surgery, and number of local anesthetics carpules (P≤0.05). Conclusion: It is recommended to identify high-risk groups when performing extraction to consider pre-operative and post-operative measures in order to reduce postoperative complication [ABSTRACT FROM AUTHOR]

Background and Aim: Odontogenic myxoma is a benign, uncommon odontogenic tumor that includes about 3 to 6% of odontogenic tumors and has an ectomesenchymal origin. It usually occurs in the second to fourth decade of life. Its common site is lower jaw and posterior parts. Treatment of lesion is complete surgical excision of tumor. Case Report: The patient, a 17-year-old girl, complained of swelling of palate two months ago. In the panoramic radiograph, a single, multilocular, radiolucent lesion with relatively well demarcated borders was observed on left side of maxilla. The lesion had spread from midline to mesial of left second molar. The lesion was removed by osteoctomy. In microscopic examination, the possibility of myxoid neurofibroma was raised due to presence of wavy cells. Neurofibroma diagnosis was rejected by immunohistochemical method and odontogenic myxofibroma was diagnosed. Conclusion: In clinical and radiographic examination of this tumor, the possibility of a non-odontogenic lesion of nerve origin was raised, and in microscopic examination of excisional sample, due to the observation of wavy cells, the possibility of a myxoid neurofibroma was raised, but the IHC findings were not in favor of it. Therefore, definitive diagnosis requires relationship between clinical and radiographic findings and examination of various microscopic sections, and in case of doubt, IHC should be performed. Since odontogenic myxoma is a locally invasive lesion and has the potential for recurrence, its correct diagnosis is of great importance. [ABSTRACT FROM AUTHOR]

Background and Aims: Endocrown is a type of monoblock restoration using the pulp chamber and remaining coronal tooth structure for retention. Advancements in adhesive techniques have breathed fresh spirit into endocrown. Nowadays, there are two approaches for endocrown: conventional approach and biomimetic approach. This study aimed to review data on the steps and clinical and philosophical points of using these approaches to help dentists' selection and performance. Materials and Methods: The review was conducted by reviewing the articles available in PubMed, Scopus, and Google Scholar databases from 1995 to 2022. The keywords used were; Crown, Endodontically-treated teeth, Light-curing of dental adhesive, Onlay, and Post-Core. Results: After removing duplicates, titles/abstracts were reviewed. Animal studies, studies without available full text or non-English language studies were excluded from the study. Then, the full texts of the remaining 59 articles were evaluated and 49 articles were eligible for the present study. The articles included clinical trials, in vitro, systematic reviews, and case reports. Conclusion: Endocrown is a successful alternative to crown, especially in molar teeth. Regardless of the conventional or biomimetic approach, this treatment has a more favorable fracture pattern while preserving the remaining tooth tissue as much as possible. [ABSTRACT FROM AUTHOR]

Background and Aim: osteoblastoma is one of the rarest primary bone tumors with the potential for local invasion and recurrence. Although this disease is more common in vertebrae or small long bones, it rarely causes lesions in the jaw bones with a high tendency to involve the mandible. Correct diagnosis of osteoblastoma is very important because in cases where the lesion is percellular, it leads to misdiagnosis with osteosarcoma. Case Report: The patient was a 52-year-old woman with a radiolucent lesion in the apical area of the molars. At right side of the mandible. The lesion continued from the mesial root of the third molar to the mesial root of the first molar. For histopathological examination of the tumor lesion after surgery, four lesions were removed. To remove them, the wisdom teeth and the first and second molars were also removed. Conclusion: Jaw osteoblastoma is a rare tumor and its nonspecific clinical and radiographic manifestations cause diagnostic problems. [ABSTRACT FROM AUTHOR]

Background and Aim: Nowadays, in the treatment of necrotic teeth with open apex, based on the availability of bioceramic biomaterials with the ability of calcified tissue induction on cement and bone and periodontal ligament repairment stimulation using these materials has become more acceptable than the traditional calcium hydroxide apexification method. Cold ceramic is one of these bioceramics that in previous studies has shown successful results in the treatment of apexification. Case Report: This article was a report of a successful case of apexification with cold ceramic and 10-months follow up of second mandibular molar tooth of a 14-year-old girl. In 10-month-old follow up, the tooth was asymptomatic and the periapical lesion healed after 10 months. Conclusion: : It seems that cold ceramic could be used as a desirable material in the treatment of apexification and to strengthen the regeneration of periapical tissue. [ABSTRACT FROM AUTHOR]

Introduction: Quality of root canal treatment is considered as an important prognostic factor for endodontic therapy success. The aim of this study is to evaluate radiographic errors during the root canal treatment by 5th and 6th year undergraduate students of Islamic Azad university of Isfahan (Khorasgan) from 2015 to 2018. Materials & Methods: In this study records of 860 cases of endodontic treatment of patients referred to the General Endodontics Department and the Comprehensive Treatment Department of Isfahan Azad University (Khorasgan) during 2015-2018 including 1903 root canals that had received root canal treatment were examined. Periapical radiography was used to evaluate errors during access cavity preparation, canal preparation, and canal filling by two endodontic specialists and it was recorded in pre-prepared forms. In the access cavity preparation: furcation perforation, low access cavity expansion, high access cavity expansion were evaluated. During the canal preparation phase, errors such as missing of canal, ledge, transport, perforation types and broken instruments were investigated. Length and density of root filing were the criteria evaluated at the canal filling stage. The analysis was performed at both descriptive and inferential levels. Statistical analysis was performed by Chi-Square test and exact Fisher's test. Results: Frequency of acceptable root canal treatment (without errors) was 37.5%. Lower first molars showed the highest error rate (40.7%). Furcation perforation was reported with 9.4% highest error of access cavity preparation. The highest error rate was reported transport (7.8%) in the preparation phase. Inadequate density (gap) of 36.9% and under filling of 31.1% had the highest error in filling stage. Conclusion: According to the results of this study, it can be stated that general endodontics department needs careful planning to increase the quality of root canal treatments performed by students. [ABSTRACT FROM AUTHOR]

Introduction: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to external root resorption of the adjacent second molar. The aim of this study was to evaluate the prevalence and quality of this resorption using cone-beam computed tomography scanning. Materials & Methods: In this descriptive study, CBCT images selected from 60 patients (including 107 maxillary & mandibular impacted third molars) were obtained from patients referring to maxillofacial radiology department of dental faculty of Islamic Azad University of Isfahan (Khorasgan) in 2016. Under observation of oral radiologist, the images were examined (two times with one-week interval) in axial, coronal, and sagittal sections and recorded to diagnose external root resorption in CBCT. The data were analyzed via descriptive statistics including contingency tables and relative abundance. Results: The prevalence of external root resorption of second molar, adjacent to the third molar were 43.25%. The most common type of third molar impaction were mesioangular third molars (41.1%) and in the next level were the vertical (28.1%), and distoangular (18.7) and then horizontal (12.1). The most common location of resorption in mandibular second molar teeth was in 1/3 of cervical (62.5%), and then 1/3 oo oooooo (20.8%) ooo 1/3 oo ooo oooooo (12.5%). oooo ooo oo ooooo ooooooooooo (4.2%) was between the 1/3 of apical and 1/3 of the middle. The most common site of resorption in maxillary second molar teeth was at 1/3 of the apical (68.45%), and then at the 1/3 of the middle (17.35%) and 1/3 of cervical (8.7%). With regards to the severity of resorption; 78.96% of resorptions were mild, 12.03% severe, and 9.03 were moderate. Conclusion: The prevalence of this type of resorption is almost high and the most common position of impacted third molars that resulted in this type of resorption are mesioangular and horizontal. Most common site of resorption in the maxilla was 1.3 of the apical and in the mandible was 1.3 of the cervical, which were often mild in resorption. [ABSTRACT FROM AUTHOR]

Introduction: Fanconi anemia is a rare autosomal recessive disease that is associated with chromosome failure and impaired DNA repair. The aim of this study was to report a case of Fanconi anemia and to manage the treatment of deciduous tooth pulp and its periodic clinical follow-up. Case Report: The patient is a six-year-old boy with a definitive diagnosis of Fanconi anemia who referred to the Pediatric Dentistry Department of Isfahan University of Medical Sciences with a complaint of deciduous tooth decay and pain on chewing food. The patient had prominent signs like short stature, hirsutism, pigmented face, contiguous eyebrows, coarse hair, protruding forehead, flat nose bridge and large ears. Conclusion: Despite the low platelet count, it was possible to treat two teeth simultaneously in one session and no particular problem has been observed until the case is reported. It is recommended that taking into account the general health of the patient is very important in providing a treatment plan. [ABSTRACT FROM AUTHOR]

Introduction: Orthognathic surgery not only changes the appearance of the face and the occlusion, but also changes the biomechanics and force of chewing. The aim of this study was to evaluate the maximum changes in byte force after orthognathic surgery in class III patients. Materials & Methods: In this clinical trial study, 20 class Ш skeletal patients referred to the School of Dentistry of Isfahan Azad University in the academic year 97-98 were selected and were divided into two groups before orthognathic surgery and 3 months after orthognathic surgery. The surgical technique in these patients was 2-jaw technique (Lefort 1 and BSSO). The area of the first right maxillary molar and the left maxillary first molar were measured at two intervals before surgery and three months after surgery. The sensor was first placed on one side of the first maxillary molar, then on the other side, and vice versa. The measurements were repeated three times on each side and the highest number was recorded as the patient's MBF (Maximum bite force). Data were analyzed using ANOVA and Tukey statistical tests (α = 0.05). Results: Mean maximum dental bite force was significantly decreased 3 months after surgery (p value < 0.001); this did not lead to a significant difference between maximum bite force and gender (p value = 0.244). Conclusion: Maxillofacial surgery in class III skeletal patients reduces the byte force in 3 months after maxillofacial surgery. [ABSTRACT FROM AUTHOR]

Introduction: The curve of spee is very important in complete oral reconstructions and can be used as a reference for prosthetic and orthodontic reconstructions. This study assessed the curve of spee in the maxilla and mandible and its relationship with the overjet and overbite in class I, II, and III malocclusions in Iranian population. In this descriptive cross- sectional study, 75 pairs of dental casts with permanent dental system and having second molars, available in the clinic of Khorasgan Azad University and private orthodontic offices were selected and divided into three groups of 25 based on malocclusion I, II, and III. Materials & Methods: In this descriptive cross- sectional study, 75 pairs of dental casts with permanent dental system and having second molars, available in the clinic of Khorasgan Azad University and private orthodontic offices were selected and divided into three groups of 25 based on malocclusion I, II and III. The radius and depth of curve of spee were obtained. Radius of the curve of spee, the tip of canine cusps, the mesiobuccal of the first molars, and the distobuccal cusps of the second molars were joined together in the form of an arch. To measure the depth of curve of spee, the reference plan was drawn from buccal canine cusp to distobuccal cusp of the second molars. The perpendicular lines were drawn from this line to the edge of the premolars cusp, the first molar and the second molar mesiobuccal cusp and the deepest part was regarded for the measurements. Overjet was measured as an average of 6 upper anterior teeth and overbite as an average of 4 anterior lower teeth and the values of radius and depth of horseshoe curvature and overbite and overjet values were analyzed by One-way ANOVA and Tukey test and Correlation between data was also examined by Pearson correlation coefficient test (p value = 0.05). Results: In class II malocclusion, overbite values had a significant relationship with radius (p value = 0.02) and depth of the curve of spee (p value = 0.04), in class III malocclusion, overbite values had a significant relationship with the curve of spee (p value = 0.001) had. In class II malocclusion, the curve of spee was deeper and overbite values were higher, and also in the class III malocclusions, a direct relationship existed between the curve of spee and overbite. Conclusion: Curve of spee effects the values of overjet and overbite, and the presence of increased overbite results from a deep spee curvature. [ABSTRACT FROM AUTHOR]

Introduction: Maxillary molars usually have three roots, four canals and the extra canal often exists in the mesiobuccal root. This study aimed to investigate the root morphology of maxillary first and second molars using CBCT. Materials & Methods: In this descriptive-analytical study, CBCT samples of 200 patients referred to maxillofacial radiology centers were selected and evaluated. Two-dimensional images in panoramic, cross-sectional, and transverse axial planes and three-dimensional images of the maxilla building that were reconstructed by a computer were examined. Analyzed data using one-way ANOVA and t-test (p value < 0.05) Results: The highest number of roots in the first molar was 3 (89.5%) and, the highest number of the second molar was 3 (90%). The maximum number of root canals in the first molar was 4 (65%) and, the highest number of root canals in the second molar was 3 (68%). The MB2 canal of maxillary first molars was 67.5% and the MB2 canal of maxillary second molars was absent at 71.5%. The presence of MB2 canal of maxillary first and second molars had no significant difference (p value > 0.05), but the presence of MB2 canal of maxillary first and second molars was significant (p value < 0.001). Conclusion: There is a significant relationship between being unilateral and bilateral with the presence of the mesiobuccal canal. Most of the first maxillary molars and, maxillary second molars had three separate roots. Also, there was no significant relationship between gender and side of study with the presence of mesiobuccal canal. [ABSTRACT FROM AUTHOR]

Background and Aim: Considering that 67 to 90 percent of dental caries in the age of 5 to 17are related to occlusal surface on molars,the use of fissure sealant has been reported as effective in reducing caries. The aim of this study was to assess the clinical effectiveness of fissure sealants placed on permanent first molars between 2016 and 2018 in pediatric department of Dental Faculty, Tehran Medical Sciences, Islamic Azad University. Materials and methods: In this cross sectional descriptive study, the files of patients in whom the first permanent molars fissure sealant was performed by dental students during 2016 to 2018 were extracted and assessed. Before the evaluation, the teeth were cleaned using tooth brush and paste . Fissure sealant retention was evaluated with probe and dental mirror on a dental chair.Data were processed by SPSS25 statistical software and logistic regression model was used to determine the effect of variables.In this study, P<0.05 was considered significant. Results: In 160 fissure sealants done, Complete retention 20.6% (33 teeth), partially retention loss 43.8 % (70teeth) and complete retention loss was 35.6 % (57 teeth) . Conclusion: It seems, more than half teeth, last fissure sealant retention during time, more than 68 percent have no caries. [ABSTRACT FROM AUTHOR]

Background and Aim: Asymmetric extractions have been proposed as potential treatment options to correct Class II subdivision malocclusion, suggesting that most side effects associated with asymmetrical mechanics can be avoided, however the post-treatment arch form may not be symmetrical. Therefore, the aim of this study was to determine the post-treatment effects of unilateral premolar extraction on the maxillary dental arch in Class II subdivision malocclusions. Material and Methods: Thirty-four patients with Class II subdivision malocclusion were treated for tooth extraction were selected. Patients were divided into two groups treated with unilateral and bilateral extractions in the maxilla. Dental arch symmetry was assessed using maxillary digital 3D casts and anterior-posterior, vertical and transverse changes of upper dental arch was calculated. The amount of displacement of the molars and canines were recorded and the changes in inclination of incisors was also measured on lateral cephalography. The T-test and test was used for each index with normal distribution and Mann-u Whitney test was used for specific data with abnormal distribution. Results: The amount of molars asymmetry in the unilateral extraction group in the transverse dimension was 0.15 mm and in anterior-posterior dimension 4.55 mm more than bilateral extraction group which was statistically significant (p≤0.001). However, in the vertical plane, the molars showed statistically insignificant differences. The amount of canines' asymmetry in the unilateral extraction group in the transverse, vertical and anterior-posterior dimension was 0.18 mm, 0.58 mm and in 0.60 mm respectively, when compared with bilateral extraction group which was statistically significant (p≤0.0001). The difference in the inclination of the upper anterior teeth at the end of treatment was also statistically significant. Conclusion: The effect of unilateral premolars extraction on the symmetry of the dental arch form is significantly different from bilateral premolars extraction. Asymmetry of the molars at the end of treatment, the amount of anterior displacement of the molars on the extraction side and the amount of posterior canine displacement on the traction side were clinically significant. [ABSTRACT FROM AUTHOR]

Background and Aims: Knowing the depth and type of the teeth impaction with radiographic approaches can guide the clinicians into selecting the most appropriate treatment and prevent surgical complications. Therefore, the purpose of this article was to evaluate the prevalence of canine and premolar impaction in the digital panoramic view of patients referred to Rasht dental school in 2019. Materials and Methods: This annalistic-descriptive cross-sectional study comprised patients who attended the Faculty of Dentistry, Rasht, Iran in 2019. Dental records and panoramic radiographs of 500 patients were reviewed retrospectively. Demographic information as well as the type and depth of impaction, involved jaw, and also, the associated pathological lesions were recorded. Data were analyzed with SPSS24 version with significant level of P<0.05. Results: The findings revealed that among 500 individuals (300 (60%) were females and 200 (40%) were males), 35 individuals (7%) had at least one impacted tooth, 80% of impacted teeth were canines and the others were premolars. The most common impaction type, impaction level, and pathological lesion were mesioangular, B, and carries of the adjacent tooth, respectively. A significant relation was not observed between the type and level of impaction with the involved jaw (P=0.15, P=0.99) and also, the relation between the type of pathological lesion and gender was insignificant (P=0.85). Conclusion: Functional and esthetic complications of impacted tooth can be prevented or declined by on-time radiographic screening. [ABSTRACT FROM AUTHOR]

Introduction: One of the simplest methods to predict mesiodistal width of permanent canines and premolars is using Tanaka and Johnston’s prediction formula; however, dental size varies according to race. The study aimed to examine the relationship between incisors mesiodistal width and mandibular first molar’s with mesiodistal width of maxillary and mandibular canines and premolars and to determine the reliability of Tanaka and Johnston prediction formula. Materials & Methods: In the present cross-sectional study, 200 pairs of a dental cast of 12-25 years old were selected and the greatest mesiodistal width of canines and premolars crown in each jaw and incisors and mandibular first molars were measured with a digital caliper with 0.01 resolution. Data were analyzed using regression analysis, t-test (p value < 0.05). Results: There was a significant statistical difference between actual width and Tanaka and Johnston prediction formula in the group under study (p value < 0.001). Moreover, a new linear equation for the prediction of mesiodistal width of maxillary and mandibular canines and premolars based on mesiodistal width of lower incisors and mandibular first molars was developed using regression analysis. Conclusion: In statistical terms, Tanaka and Johnston’s prediction formula is not applicable for the population under study because maxillary estimated measures were a little high and mandibular estimated measures were a little low. [ABSTRACT FROM AUTHOR]

Background and Aims: Nowadays, the best choice for replacing missing teeth are dental implants, however, failure is not unexpected. One of the factors that plays an important role in the implant failure is bacterial microleakage which could cause biological complication. The aim of this study was to compare the bacterial microleakage between the two types of implants. Materials and Methods: In the present interventional study, SPI and Dentis implants were placed bilaterally in the premolar-molar area of the patients' mandible. One day and 14 days after the delivery of the crown, by removing the crown and removing the abutment, sampling was performed using a sterile paper cone from four areas. One day after sample culturing, the number of colonies was counted. All data were entered into SPSS 23 and were analyzed using independent samples t-test and paired t-test with a significance level of 0.05. Results: The amount of bacteria in implant sulcus was significantly different between the two types of implants (P=0.003). After 14 days, the amount of bacteria in SPI implant sulcus significantly decreased more than Dentis implant sulcus (P=0.001). After 14 days, the amount of bacteria also decreased in all other areas which there were no significant difference between the two types of implants (P>0.05). [ABSTRACT FROM AUTHOR]

Background and Objectives: Tooth extraction is one of the ways to treat dental diseases. The aim of this study was to determine the effect of different molar tooth extraction patterns on short-term and middle-term memory in rats. Materials and Methods: In this experimental study, 45 male Wistar rats were divided into three groups: control group (C) without pulling, pulling group 1 (E1) by pulling bilateral maxillary molars, and pulling group 2 (E2) by pulling the left maxillary and right mandibular molars. The Maurice Watermase test was performed to assess spatial memory. Tukey's test was used to analyze the data. Results: In short-term memory tests, the number of visits to the target area was significantly lower in group E1 than in group C (p=0.003). In group E2, the time spent in the target area and the distance traveled in the target area was longer than group E1. Conclusion: This study explained that the molar teeth extraction may impair the memory ability. Keywords: Molar tooth extraction, Short term memory, Middle-term memory, Rat Funding: This research was funded by Neuroscience Research Center, Kerman University of Medical Sciences. Conflict of interest: None declared. Ethical approval: The Ethics Committee of Neuroscience Research Center, Kerman University of Medical Sciences approved the study (IR.ATU.REC.98000078(. How to cite this article: Pourgholamali N, Shojaeepour S, Shojaeipour R, Jahanimoghadam F. Effect of Different Patterns of Molar Teeth Extraction on Memory in Rats: A Short Report. J Rafsanjan Univ Med Sci 2020; 19 (8): 899-906. [Farsi] [ABSTRACT FROM AUTHOR]

Background & Aim : This study was aimed to compare the instrumentation time and the amount of debris extruded apically during root canal preparation using hand files,Mtwo rotary system and endodontic handpiece in primary molar teeth. Method & Material : In this experimental study, sixty roots of primary molars of human teeth were assigned to three groups (for each group, n=20). The canals were then instrumented with the following instrument systems : Mtwo rotary, endolift and hand files. Debries during instrumentation was collected into pre-weighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70°C for 5days. The weight of the dry extruded debris was established by pre-instrumentation and post instrumentation weight of the Eppendorf tubes for each group. Instrumentation time was also recorded. The data of debry extrusion and instrumentation time were respectively analyzed using one - way analysis of variance (ANOVA) and Kruskal-Wallis tests. Result: Hand files were associated with more apically extruded debris than the Mtwo rotary and endodontic handpiece (P<0.05 ).Intergroup comparison of the instrumentation time didn't show a statistically difference between the three groups (P>0.05) Conclusions: It seems, Mtwo rotary and endodontic hand piece, produced less debries v.s to hand instrumentation of primary molar canals. All instruments were associated with apical extrusion of debris and in terms of the instrumentation time, no method was faster than any other ones. [ABSTRACT FROM AUTHOR]

Background and Aim: The third molar tooth lies with symptoms such as periodontal problems, caries, crowding, root resorption, cyst and tumor formation of the adjacent second molar. The purpose of this study was performed to evaluation of the position of mandibular third molar teeth and its effect on second adjacent molar teeth. Materials and Methods: Panoramic radiography were obtained from 264 patients with mandibular third molar hidden teeth referred to the Birjand School of Dentistry in 2018. The material and direction of their placement and the vertical position of the third molar tooth (based on the PELL & Gregory classification) and its placement angle (based on Winter classification) were determined. Also, the prevalence of distal caries, external root resorption, the amount of displacement, and the amount of inflammatory lesions and the cystic was examined in the adjacent second molar tooth. Data were analyzed using SPSS software (Version 19), and chi-square statistical test, p-values less than 0.05 were considered statistically significant. Results: The data from this study showed that most of the wisdom hidden teeth were in Class B and III of Pell and Gregory classification, had Mesial angle based on Winter classification. In 20.8% of patients with caries, there was 3% root canal resorption and 1.1% displacement of the second molar tooth, while no cases of inflammatory and cystic lesions in the second molar tooth were found due to the hidden third molar tooth. The Mesial and horizontal angles of impacted wisdom teeth were associated with increased risk of caries and root resorption of the second molar. Also, Class Bchr('39')s third molar teeth increased caries in second molar teeth. Conclusion: Most pathological problems were observed in Mesial, horizontal, and class B impaction. According to the observed relationship, it seems that the angle and depth of the hidden third molar should be taken into account considered when deciding whether or not to extract it. [ABSTRACT FROM AUTHOR]

Background and Objectives: The anatomy of maxillary molars is very complicated and root canal therapy for this specific group of teeth is a major challenge for dentists. Given the limitations of conventional techniques for finding the second mesiobuccal canal (MB-2) and anatomical differences observed in different ethnicities, this study aimed to determine the anatomy of mesiobuccal root canal in maxillary first permanent molars using CBCT (Cone-beam computed tomography) in Rafsanjan city. Materials and Methods: In this descriptive study, 41 promax 3D CBCT radiographs of patients in Rafsanjan in 2018 were studied. To investigate the root morphology, after obtaining multiple planar reformation (MPR) images in sagittal and axial planes, evaluation was done by Vertucci classification. Data were analyzed using chi-square test or Fisher's exact test. Results: Of the 41 studied films, one canal was observed in mesiobuccal root in 15 (36.6%) films and two canals in the others 26 (63.4%) films. Among the roots containing two canals, second type of Vertucci classification was the most common type observed. It should be noted that there was no significant relationship between the number of canals and also the type of canals and gender (p=0.495 and p=0.583, respectively) and with quadrant of the tooth (respectively p=0.133 and p=0.669). Conclusion: According to the results of the present study and the amount of two-canal mesiobuccal roots, it can be said that the preparation of CBCT film before root canal therapy in maxillary first molar is necessary to verify the existence and type of MB-2 canal. [ABSTRACT FROM AUTHOR]

Introduction: Internal root resorption is a pathologic process, which follows dental pulp inflammation. In this process, multinucleated clastic giant cells resorb the root dentin. Several etiologic factors, including orthodontic forces, trauma, the heat generated during cavity preparation, and caries, are held responsible for this process. In case of delayed diagnosis and intervention, this process might lead to root perforation and formation of a periapical lesion, which might complicate further treatment. Case Report: Non-surgical root canal treatment was performed on a 35-year-old female with tenderness to percussion after the diagnosis of internal root resorption with the CBCT technique. The resorption had caused root perforation. The patient was scheduled for a one-year follow-up. [ABSTRACT FROM AUTHOR]

Introduction: Implants angles relative to each other might result in inaccurate impressions, resulting in inaccurate master casts. This study aimed to evaluate the dimensional accuracy of master casts in angulated dental implants. Materials & Methods: In this in vitro study, a unilateral partially edentulous acrylic model was prepared with two implants in the second premolar and second molar areas. Impressions were taken in nine different positions of the implant positions (0°, +15°, -15°), using two impression techniques (closed tray, open tray) (n = 3) with polyvinylsiloxane impression material. The master casts were scanned by a laser scanner, and the data were transferred to Materialise Magics software to measure the angulation between the implants. The dimensional accuracy of the impressions was calculated in different implant angulations (i.e., parallelism, divergence and convergence of two implants). Data were analyzed using independent t-test and two-way ANOVA (α = 0.05). Results: With a 0° angle between the implants (parallelism), there was no significant difference between the two impression techniques (p value = 0.102). However, when there was a >15º angle between the two implants, the open tray technique was significantly more accurate than the closed tray technique (p value ˂ 0.05). Conclusion: The implant angulation and impression techniques affected the accuracy of the master casts. When implant angulation increased from 0° to 30°, the distortion of the impressions increased, too. [ABSTRACT FROM AUTHOR]

Background and Aims: Considering the role of primary teeth in children's dental health and the importance of parental role on children dental health the purpose of this study was to determine the knowledge and practice of parents of 3-9 year-old children regarding to maintaining primary teeth. Materials and Methods: This cross-sectional descriptive-analytical study was conducted on the parents referring to Ahwaz dental school in 2017. Using a questionnaire, the participants' demographic characteristics, knowledge and performance regarding maintaining of the primary molars were collected. The percentage of correct responses was considered as the level of knowledge and performance. Analysis of K-square and Spearman and Pearson correlation coefficient and T-test were employed to determine the relationship between the participants' knowledge and performance and their demographic variables. The significance level was P<0.05. Results: 176 parents completed the questionnaire. The mean parental knowledge score was 57.42±7.45 (range 15-75), and the mean practice score was, 9.42±1.86 (range 4-12). No relationship was found between the parents' age, sex, knowledge, and performance. The knowledge of parents who had a history of referral to the dentist, fewer children (rs=0.428), higher education (rs=0.490) and higher income (r=0.226) was significantly better (P<0.001). Also practice increases with higher awareness of parents (r=0.549) (P<0.001). The parents' practice was significantly related to the history of referral to the dentist, and having fewer children (rs=0.320), higher education (rs=0.369), and higher income (r=0.253) (P<0.01). Conclusion: The findings of this study showed that the knowledge and practice of the parents about primary teeth were moderate. Regarding the important role of primary teeth in children's health, increasing the parents' knowledge on the maintenance of primary teeth is essential. [ABSTRACT FROM AUTHOR]

Background and Aims: One of the most important challenges for dentists is providing a crown with appropriate marginal fit and gap. The 135-degree tooth preparation found to have some advantages such as technical ease and appropriate finish line record. Despite the advantages of 135-degree tooth preparation, scant research has been done in this area. Therefore, the aim of this study was to compare 135-degree and deep chamfer tooth preparation on the marginal fit and marginal gap of posterior metal-ceramic crowns. Materials and Methods: Deep chamfer and 135-degree tooth preparation were performed on the two first mandibular molars with healthy coronal tissue and similar size. Impression was taken from each tooth and 30 crowns were made on each die. The sample plastered with fit checkers were pressed under the force of 40 N for 3 min in a universal testing machine. They were measured and recorded under a loop with 40x power in three points on each aspect. Data were analyzed by Wilcoxon and Kolmogorov-Smirnov tests using SPSS version 24. Results: The mean marginal fit values in deep chamfer and 135-degree were 48.5417μm and 55.3333 μm, respectively with no statistically significant difference (P>0.05). While the mean marginal gap in deep chamfer (2.4833 μm) was significantly higher (P<0.05) than 135-degree (1.0083). Conclusions: It can be concluded that the marginal gap by 135-degree's tooth preparation was lower than that of deep chamfer in metal-ceramic crowns. However, no significant difference in the marginal fit between the deep chamfer and 135-degree tooth preparation was found. [ABSTRACT FROM AUTHOR]

Background and Aims: Various methods to induce anesthesia have been investigated in situations where the primary inferior alveolar nerve block (IANB) injections fail. The aim of this study was to compare the effect of synergic effects of anesthetic injection of prilocaine supplemental with that of lidocaine anesthesia in teeth with irreversible pulpitis. Materials and Methods: This study was a parallel-controlled clinical trial on 58 patients with one mandibular molar tooth having irreversible pulpitis. The first anesthesia was injected with an inferior alveolar block with 2% lidocaine anesthesia. Patients who failed pulpal anesthesia were randomly divided into two groups; case and control groups. In the case group, IANB was injected with 3% prilocaine, and in the control group with 2% lidocaine anesthesia. Anesthesia after the second injection was evaluated by three methods of numerical evaluation of the patient's response to Electric Pulp Tester (EPT), the severity of the patient's response to the cold test, and the extent of pain during the onset of access cavity latency on the Visual Analog Scale (VAS). Statistical analysis was performed using T-test and Mann-Whitney tests. Results There was no significant difference between the two groups in terms of depth of anesthesia (P>0.05). Conclusions: The results of this study showed that there was no difference between 2% lidocaine and 3% prilocaine in the depth of supplemental IANB anesthesia after failure of first IANB in mandibular molar teeth with irreversible pulpitis. [ABSTRACT FROM AUTHOR]

Background & Aim: Apical extrusion of debris is one of the reasons for flare-up(pain,swelling,or both). This study aimed to determine the apical debris extrusion of two rotary systems(RaCe and Komet F6 SkyTaper) in curved mesiobuccal canals of mandibular first molars. Material and methods: Thirty mandibular first molars (with mesiobuccal canal curvature 25-35 degree) were included in this experimental study and divided randomly into two experimental groups.Root canals in group 1 prepared with RaCe and group 2 prepared with Komet F6 SkyTaper system.The roots were fixed in preweighted vials in order that extruded debries accumulate in lower chamber, after desiccation of the chamber exact weight of debris were evaluated. The datas were analysed by T-test (p<0.05). Results: The mass debris extruded weight in RaCe group was 1.76±0.925 g, while in Komet group was 1.73±0.02909 g and the differences was insignificant ( p= 0.2). Conclusions:It seems, Race and Komet F6 systems have not singinficant differences considering the extruded debreis in preparation of dental canal procedures. [ABSTRACT FROM AUTHOR]

Introduction: The most favorable orthodontic treatment outcomes are obtained when the treatment starts at the most appropriate stage of growth. In such a case, it will have the least potential complications and the best therapeutic stability. Many researchers have shown that chronological age is not a reliable method for evaluation of skeletal development. It is very important to use a reliable index to identify different stages of skeletal maturation. The aim of this study was to examine the relationship between maturation of cervical vertebrae and calcification of teeth in children 9- 14 years of age. Materials & Methods: In this cross-sectional study, cephalometric and panoramic radiographs of 200 patients were used. The patents were aged 9‒14 years and had referred to the Department of Orthodontics of Isfahan Dental School and specialty clinics. In this study, to determine the calcification of canines, first premolars, second premolars and second molars, Demirjian et al technique was used; in addition, Baccetti et al technique was used to evaluate the different stages of skeletal maturation. Data was analyzed using SPSS 23 and Spearman’s correlation coefficient (α = 0.05). Results: The results of this study showed a significant correlation between the calcification of canines, first and second premolars, and the second molars on both the left and right sides with different stages of cervical maturation. Spearman’s correlation coefficient for different teeth were as follows: canines, r = 0.5; first premolars, r = 0.5; second premolars, r = 0.6; and second molars, r = 0.6; p value < 0.001). However, in boys the relationship was significant only in the left molar teeth (r = 0.3), right molar teeth (r = 0.26) and left canine teeth (r = 0.3), (p value < 0.001). Conclusion: Conclusion: The correlation between calcification of teeth and cervical vertebrae in girls was significant; in boys it was significant only in second molar teeth and left canine teeth. [ABSTRACT FROM AUTHOR]

Background and Aims: Despite patient's demand increased for tooth color restorations, the stable bond between dentin and composite is a challenge in dentistry. Dentin protease activation is responsible for dentin-resin bond failure. The aim of this study was to determine the best pretreatment agent to inhibit matrix metalloproteinase and increase resin-dentin bond durability. Materials and Methods: After collecting 24 intact third molars, the dentin surfaces were exposed immediately under DEJ. After acid etching of dentin rewetting was done with CHX 2%, EDC 0.3 M for 60 and water (control group). Then the adhesive (Single bond, 3M ESPE, USA) and composite (Filtek Z250 XT, 3M ESPE, USA) were applied. 48 sectioned dentinal specimens were prepared. The specimens were divided into 3 groups. Each group was divided into 2 sub groups (n=8). In half of each group, the micro tensile bond strength test was done immediately and another part half 6 months. Then, the specimens were evaluated by stereomicroscope and SEM. Statistical analysis was performed using SPSS23 software, twoway ANOVA and multiple Tukey and T-test comparisons. P<0.05 was considered as a significant level. Results: There were not significant differences between immediate micro tensile bond strength of CHX, EDC and control groups (P=0.97). However, there was significant differences between CHX, EDC compared with the control group (P≤0.0001). Comparison between the immediate and 6-month bond strengths in each group, only in EDC group, there was no significant after 6 months' difference (P=0.64). Conclusion: EDC and CHX t did not have any effect on the immediate microtensile bond strength. After 6 months, EDC prevented bond strength deterioration, but the bond strength was decreased after CHX usage. [ABSTRACT FROM AUTHOR]

Introduction: Pain control in dental treatment, especially in root canal treatment, is an important issue. The aim of this study was to investigate the effect of dexamethasone infiltration along with the inferior alveolar nerve block with lidocaine with 1:80000 epinephrine on postoperative pain in posterior teeth with irreversible pulpitis. Materials & Methods: In this clinical trial, 60 patients with irreversible pulpitis and acute pain in lower molar teeth were selected and randomly divided into two groups. After standard block injection for each patient, buccal infiltration injections of dexamethasone or normal saline solution was performed. Preoperative pain was recorded using visual analogue scale (VAS) from 0 to 10 before treatment, and at 4-, 6-, 12- and 24-hour postoperative intervals. Data were analyzed with independent t-test and chi-squared, Mann-Whitney and Friedman tests (α = 0.05). Results: There were no significant differences between the two groups in age, sex, tooth and pain severity before treatment. Pain in the control group 12 and 24 hours after treatment was significantly less severe than that at 4-hour interval; however, in the dexamethasone group this difference was not significant. By controlling confounding factors, preoperative pain significantly affected the pain after treatment at 4 and 6 hours. Gender affected pain at 12-hour postoperative interval. Conclusion: Buccal infiltration of dexamethasone significantly affected pain at 4- and 6-hour postoperative intervals. Preoperative pain significantly affected pain at 4- and 6-hour postoperative intervals in mandibular molars with irreversible pulpitis. [ABSTRACT FROM AUTHOR]

Introduction: One of the most important issues in pediatric dentistry is pain control during treatment. The inferior alveolar nerve block has some limitations as a conventional technique for the anesthesia of mandibular permanent molars, necessitating the use of alternative techniques, one of which is the infiltration technique. The aim of this study was to compare the efficacy of inferior alveolar dental nerve block using lidocaine with infiltration technique with articaine in mandibular first permanent molar anesthesia in children 8−11 year of age. Materials & Methods: In this randomized cross-over clinical trial on 42 children 8−11 year of age both mandibular first permanent molars were restored. Block or infiltration injection was selected randomly. Patient's behavior was registered in two steps of injection and restoration using the SEM scores. For comparison of the two sides, Wilcoxon signed rank test and SPSS 20 were used (α = 0.05). Results: Based on the results, the infiltration technique resulted in a decrease in all the three SEM scores compared to block injection (p value < 0.05). There was no significant difference in the efficacy of these two anesthetic techniques (p value > 0.05). Conclusion: It appears that infiltration technique with articaine is a better alternative for block technique with lidocaine in the restoration of the mandibular first permanent molars. [ABSTRACT FROM AUTHOR]

Introduction: Suturing is a common procedure during surgeries to fix surgical flaps to improve tissue integration during healing phase. The aim of this study was to make a histological comparison of gingival tissue reaction in the vicinity of silk and vicryl suture materials during the initial healing phase in crown lengthening surgeries. Materials & Methods: The present double-blind, randomized clinical trial had a paired design method. This study was performed on 24 sites in 12 patients with an age range of 20-40 years, needing crown lengthening surgery of maxillary premolars and molars. The subjects had no systemic problems or gingival inflammation at the surgical sites. The sutures were placed in the surgical sites 7 days before the crown lengthening procedure. Vicryl and silk sutures were placed on the mesial or distal gingival papilla of each tooth randomly. All the suture materials used in this study were identical in term of physical dimensions (4-0). After 7 days, during crown lengthening surgery, gingival tissues along with suture materials were harvested for histological examination. Then the severity of inflammation and infiltration of inflammatory cells were evaluated in tissue specimens using Wilcoxon test (α = 0.05). Results: The study indicated that vicryl suture material resulted in less infiltration of the inflammatory cells in the gingival tissues compared to silk sutures (p value = 0.001). Conclusion: Considering the lower infiltration of inflammatory cells in the vicinity of vicryl suture material, it seems in procedures such as oral surgeries, vicryl suture could be an appropriate alternative for silk material. [ABSTRACT FROM AUTHOR]

Background and Aims: The structural distinction of primary teeth compared to the permanent teeth leads to a faster penetration of the caries into the pulp, which makes effective treatment necessary. The aim of this study was to determine the success rate of pulpotomy in primary molar teeth and its effective factors using formocresol by students and residents at the department of pediatric dentistry of Hamedan dental school. Materials and Methods: In this cross-sectional study, 113 children who previously had pulpotomy by formecresol in their primary molars (30 children by residents and 83 children by the students) were randomly evaluated based on referral time (at least 12 months after treatment) in terms of clinical and radiographic success rates. Data were analyzed by SPSS20 software using Chi-square and descriptive statistics. Results: The success of the pulpotomy of primary molar teeth was 81.7%. The success rates of the general students and residents were 79.3% and 87.3%, respectively. The percentage of successful pulpotomy was significantly higher in general students at Stainless Steel Crown (S.S.C), second molar in maxilla (P<0.05), but did not have a significant relationship with age and sex (P>0.05). The percentage of pulpotomy success performed by residents did not have a significant correlation with gender, age, type of repair, type of teeth and jaws (P>0.05). In general, the percentage of success in S.S.C, the second molar and maxillary jaw was higher. Also, the success rate of pulpotomy by residents was significantly higher than that of general- students (P<0.05). The highest rates of pulpotomy failure were related to internal analysis. Conclusion: Formocresol pulpotomy using S.S.C in the maxillary second molar teeth had higher success rate. [ABSTRACT FROM AUTHOR]

Introduction: The preventive role of pit and fissure sealants against dental caries has clearly been shown. Two new categories of self-etching (Itena) and hydrophilic (Smartseal & Loc F) fissure sealants have recently been marketed. The aim of this study was to investigate and compare microleakage of these innovative fissure sealants with a conventional sealant material (3M). Materials & Methods: Seventy-five sound extracted third molars from both jaws with no caries or cracks were selected for the purpose of this in vitro study and assigned to three groups. The teeth were cleaned with pumice powder and water, rinsed, dried and prepared. The occlusal pits and fissures were etched using a 37% phosphoric acid ethant gel (3M) for 20 s, rinsed for 15 s and dried. In each group, the assigned sealant material was applied over the pits and fissures and cured for 20 s: self-etching (Itena), hydrophilic (Smartseal & Loc F) and conventional sealant material (3M). The samples were then stored in 0.5% volatile fuchsine solution for 48 hours. The samples were then rinsed and sectioned in the buccolingual direction. The samples were then investigated at ×24 magnification under a stereomicroscope for depth of dye penetration. Data were analyzed with using Kruskal-Wallis and Mann-Whitney tests at a significance level of p value < 0.05. Results: Comparison of the means showed the highest degree of microleakage in self-etching sealant (mean = 3), which was significantly different from the hydrophilic (mean = 2) and conventional (G = 0.84) fissure sealants (p value < 0.001). However, there was no statistically significant difference between conventional and hydrophilic fissure sealants (p value = 0.21). Conclusion: The results of the present study showed that the microleakage of self-etching sealant was higher than the two other fissure sealants. [ABSTRACT FROM AUTHOR]

Introduction: To date, no data have been reported on the demographics of implants placed in Isfahan University of Medical Sciences. The aim of this study was to collect data systematically from implant records and construct a database to improve access to them. Materials & Methods: In this descriptive study, all the patient records were reviewed from September 2012 to September 2016. The data in the records was extracted in terms of the demographic medical history, surgical, prosthetic and follow-up factors. Finally, data were analyzed with SPSS 23, using descriptive statistical methods. Results: A total of 640 patients have received 1890 dental implants, with 70.5% of the implants placed in the 41‒70-year age group and the greatest number of implants inserted in the posterior mandible (37.2%) and the first molar region. Bone augmentation procedures were performed in 50.5% of implants, with the highest incidence in the anterior maxilla. The most commonly used bone material was Cerabone and the most commonly used membranes were Osseoguard and Cytoplast. In addition, the most commonly used implant brand was Zimmer. Regarding dimensions of the implants, a diameter of 4.1 mm and a length of 12 mm were most often utilized. Bone-level implants (59.5%) were used more frequently than tissuelevel implants (40.5%). Conclusion: According to the results of this study, it can be concluded that the majority of patients referring to the Implant Department of Isfahan Dental School are over 50 years of age and bone augmentation techniques are also used in over 50% of cases. [ABSTRACT FROM AUTHOR]

Introduction: Idiopathic osteosclerosis is a localized growth of compact bone with an unknown cause. This lesion is asymptomatic and does not require treatment. The aim of this study was to determine the frequency of idiopathic osteosclerosis of jaw bones on panoramic radiographs. Materials & Methods: A total of 1122 panoramic radiographs of patients referring for dental treatment were collected in this descriptive study. Data on each radiograph were recorded, including age, sex, location of lesion (maxilla, mandible, and anterior, premolar and molar regions), relationship between the lesion and adjacent teeth (apical, apical and interradicular, no relation) and root resorption of the affected teeth. Data were analyzed with chi-squared test and independent-t test (α = 0.05). Results: Frequency of idiopathic osteosclerosis was 7%. The lesions were more frequent in females than in males; however, the difference was not statistically significant (p value = 0.195). The frequency of idiopathic osteosclerosis in the mandible, especially in the molar region, was significantly higher than that in the maxilla (p value < 0.001). In addition, lesions with no relationship with tooth roots were significantly more frequent than those with a relationship with tooth roots (p value < 0.001). Conclusion: The frequency of idiopathic osteosclerosis was higher in females, in the area of mandibular molars and the late third decade of life. [ABSTRACT FROM AUTHOR]

Introduction: Despite all efforts and various studies on reasons for and factors affecting a lack of success in inferior alveolar nerve block, profound pulpal anesthesia is often difficult in mandibular molars during endodontic treatment. The aim of this study was to investigate the effect of pain experienced during previous endodontic treatment on success rate of inferior alveolar nerve block (IANB). Materials & Methods: In this cross-sectional study, 100 healthy adult patients with a diagnosis of symptomatic pulpitis in their first mandibular molar were selected and questioned about experience of pain during previous root canal therapy. Each patient received two mandibular nerve block injections by one operator. If lip numbness happened after 15 minutes, endodontic treatment was initiated. During the treatment, the patients were asked to rate the pain during access cavity preparation or upon insertion of the initial file into the root canal on Heft-Parker visual analog scale (VAS). Success was defined as no or mild pain during treatment. The initial pain was analyzed with Mann-Whitney test; age was analyzed with t-test; and success of anesthesia and gender were analyzed with chi-squared test. Statistical significance was set at p value < 0.05. Results: The success rate for the IANB was 30% in the group with pain experience and 74.3% in the group without pain experience during previous endodontic treatment, with significantly higher success rate in the group with no previous pain experience (p value < 0.001). Conclusion: There was a significant relationship between pain experienced during previous endodontic treatment and failure rate of IANB. [ABSTRACT FROM AUTHOR]

Background and Aims: One of the main disadvantages of light cured composite resin materials is polymerization shrinkage upon curing. This leads to the microleakage of restoration and finally failure of the restoration. The purpose of this study was to investigate the effect of two types of light curing devices with different modes on the microleakage of posterior composite filling in Cl II restorations. Materials and Methods: In this experimental study, 30 extracted sound molar human teeth were collected. All specimens were randomly divided into 3 groups of ten: Standard LED irradiation, pulse curing LED irradiation and QTH irradiation. All samples were prepared with mesial and distal boxes and composite fillings were done with three different light curing patterns for 20 s. After thermocycling, the specimens were kept in 2% methylene Blue solution for 24 h for microleakage test. After sectioning, the samples were evaluated by a stereomicroscope. For data analysis one-way ANOVA and Kolmogorov-Smirnov were used. P<0.05 was considered statistically significant. Results: The quantitative tests showed that there were no statistical difference between study groups (P>0.05). Conclusion: The results showed that both light curing devices were effective and no significant difference between different modes of LED light curing device on microleakage of class II composite restorations was found. [ABSTRACT FROM AUTHOR]

Introduction: Periapical diseases are the end result of untreated pulpitis or failure of root canal therapy. The aim of this study was to evaluate and compare the prevalence of different periapical lesions in terms of demographic variables in patients referring to the Department of Oral Pathology of Isfahan Dental School in three different time periods from 1988 to 2015. Materials & Methods: In this retrospective cross-sectional study, biopsy samples available in the archives of Oral Pathology Department of Isfahan Dental School from1988 to 2015 were studied. Periapical (PA) lesions were evaluated and compared in terms of age, sex, type, etiology and location. Data were analyzed with SPSS. After data collection, data were analyzed with chi-squared test, Fisher’s exact test, ANOVA and Tukey test (α = 0.05). Results: Of 10686 oral biopsies, 582 (5.44%) were PA lesions. Of 582 PA lesions, 71.1% were dental granulomas and 15.3% were radicular cysts and the other cases were other lesions with lower prevalence rates; 41.4% of the lesions belonged to males and 58.1% to females. The most common frequency was detected in the 21‒30-year age group. The most common site of involvement was the mandibular molars with 48.3%, maxillary incisors with 32.5% and maxillary molars with 21.4%, respectively. Distribution frequencies of PA lesions were 11%, 23.9% and 65.1% in the first, second and third periods, respectively. Conclusion: The results showed that the prevalence of PA lesions has increased significantly in recent years. Increased incidence of periapical lesions secondary to root canal therapy (RCT) in the second and third periods in comparison with the first period is an indication of inadequate RCT treatment in patients. [ABSTRACT FROM AUTHOR]

Background and Aims: First molar has an important role at individual’s dental health. Among the known risk factors, the experience of previous caries is of the best predictors for future caries. The aim of this study was to examine the association of primary teeth caries and other risk factors with the incidence of permanent teeth caries by considering the caries extent and severity. Materials and Methods: This case-control study was done on 150 students from second and third grade with 9 years old. Cases included children with at least one carious permanent molar. Caries-free students who were matched based on the gender and mother education was considered as control group. Examination was done on dental unit under the unit light with blunt explorer and mirror for visual assessment. DMFT, dmft and caries severity (D1-D3) were recorded based on WHO standards. Data were calculated using SPSS18, Correlation, Chi Square Analysis, Odds ratio and Logistic regression. Results: Linear correlation between dmft in primary teeth and DMFT in permanent molars was obtained with r:0.34 (P<0.001). Decay in permanent molars in students with active caries in primary molars was 3.3 times more probable than others. In regression model, the other risk factors such as cariogenic diet, mother`s education, brushing with toothpaste, flossing, using flouride, and regular dental visiting were not significant (P>0.05). Conclusion: Caries-free primary teeth predicts permanent teeth without decay with a high possibility. It could be helpful in caries risk assessments. [ABSTRACT FROM AUTHOR]

Tooth eruption order is regular in most of children but not following the normal growth of the teeth should not always be considered abnormal. Exfoliation of deciduous teeth and eruption of permanent teeth are an important stage for child's parent and dentist. Exfoliation of teeth is dental evolutionary movement in the axial direction from its formation origin in the bone until initiating its activity in the mouth. Attention to the findings of the physical examination, the presence or absence of developmental disorders, hydrocephalus, rickets, and cleft lip and palate, and anomalies, can indicate the presence of underlying genetic diseases or endocrine disorders. In other words, teething is a component of body growth and development which is influenced by various factors, serum levels of calcium and vitamin D, and underlying diseases. Careful attention of dentists to the various signs of eye, face, skeletal, cardiac and growth disorders in children and counseling, if needed, can help them in early detection of underlying disorders. Knowing the eruption time of permanent teeth helps the dentist to identify accelerated or delayed eruption of the teeth and evaluating its causes. [ABSTRACT FROM AUTHOR]

Background and Aims: Taking impression from angulated implants has always been a great challenge in clinic. In this regard, studies on sectional trays are very few. The aim of this study was to evaluate and compare the dimensional and angular accuracy of impressions using full arch and sectional trays. Materials and Methods: Four implants (4.3 × 12 mm) (Implantium, Dentium) were placed in the first premolar and molar regions of a Kennedy class I mandibular acrylic model with 30° lingual angulation. Twenty open special trays (Full arch & Sectional) were made on the primary cast. The impressions were taken using vinyl polysiloxane (VPS) and were poured with type IV dental stone. The coordinate measuring machine (CMM) was used to measure the dimensional (Z, Y, X) and angular (θ) coordinates of implants. The data were analyzed using and t-test and SPSS 22. Software. Results: The type of tray had no significant effect on the dimensional accuracy in X, Y and Z axes (P>0.05) and total linear displacement (r); However, it significantly affected the angular accuracy (Δθ) (P<0.05). Conclusion: Sectional tray yields less rotational displacement in impressions made of angulated implants. [ABSTRACT FROM AUTHOR]

Introduction: Toothextraction is one of the invasive treatments in dentistry and in some cases it is associated with some complicationssuch as pain, dry socket and inflammation. Given the antibacterial effects of metronidazole, the aim of this study was to assess the effects of 0.75% metronidazole gel on complications after extraction of mandibular third molar teeth. Materials & Methods: This clinical trial was conducted on mandibular third molars of 20 male volunteers 20‒30 years of age. After extraction of two similar mandibularthird molar teeth, 0.75% metronidazole gel was placed in the extracted tooth socketon one side andno material was placed in the socket on the other side as control. The severity of pain and swelling were determined with visual analog scale and by determining the change in the distance ofthe angle of the mandible from thedental midline, respectively. Clinical examination was performed to determine the presence or absence of dry socket. Data on pain, swelling and dry socket were analyzed with SPSS (p value ≤ 0.05). Results: The severityof painafter tooth extraction exhibited a significant difference at6-and12- hour intervalsbetweenthetwo sides (p value = 0.04 and p value = 0.03). However, at24-and 48-hour intervals after toothextractionthe differences were not significant (p value = 0.09 and p value = 0.06). In relation to swelling, inthe area from the mandibular angle to the midline, no difference was observed between the two sides after 24 hours (p value = 0.05) but there was a significant difference between the two sides after 48hours (p value = 0.05). Thedifferenceindry socket incidence was not significant between the two sides (p value = 0.2). Conclusion: Application of 0.75 % metronidazole gel can reduce pain and swelling after tooth extraction but it might have no effect on dry socket incidence. [ABSTRACT FROM AUTHOR]

Introduction: Branchial cleft cyst is a slow-growing fluctuant mass that most commonly appears during the second and third decades of life. The most common site of this cyst is the lateral aspect of the neck and anterior to the sternocleidomastoid muscle, but it can also be found around the parotid gland, angle of the mandible and near the external ear. The cyst presented in this case report is important because of its uncommon site and its clinical presentation similar to an odontogenic abscesses, possibly leading to clinical misdiagnosis. Case Report: This report presents a case of a branchial cleft cyst which was misdiagnosed primarily as an odontogenic cyst or abscess and was treated with antibiotics for three months by a general dentist. In clinical examination there was a 5×5-cm fluctuant swelling with soft consistency in the lateral aspect of the neck and right side of submandibular area. The cyst was not tender to palpation. The panoramic view showed extensive caries of the right first molar tooth and a radiolucent lesion in the apical area of the right third molar. Following determination of the extension of this lesion by spiral CT scan, excisional biopsy was carried out under general anesthesia. Pathology report revealed branchial cleft cyst. Conclusion: The diagnosis of branchial cleft cysts mainly depends on history and clinical manifestations. CT scan is not only useful for the evaluation of the lesion but also it is useful to evaluate its relationship with adjacent structures. [ABSTRACT FROM AUTHOR]

Background and Aims: The first permanent molar is susceptible to caries, endodontic complications and developmental anomalies. Compromised teeth with poor prognosis could cause the clinician to face dilemmas. The aim of this review article was to assess recent guidelines on the treatment planning of compromised first permanent molars in mixed dentition period. Materials and Methods: The design of the study was based on review of literature by searching the MEDLINE, Web of science and Google scholar. Key words (permanent first molar, extraction, treatment plan) were used. This search was limited to the English articles published after the year 2000. Conclusion: A number of factors influenced decision-making process regarding compromised first permanent molars including the restorative status of the tooth, dental age of the patient, degree of crowding and occlusal relationships were assessed. The ideal time for removal of these teeth was 8-9 years of age. However, the current evidence for managing compromised first permanent molars demands clinical trials. [ABSTRACT FROM AUTHOR]

Background and Objectives: Working length determination is one of the most important factors in successful root canal treatment; therefore, this study was carried out to compare conventional (E-speed) and digital (CMOS) radiographies in determining the working length of the root canals of mandibular molar teeth. Materials and Methods: In this ex-vivo study, 25 permanent mandibular double-root first molar teeth were selected and then access cavities were prepared. In order to determine the real working length of the roots, the number 15K-files were transferred into the canals. After placing each sample in the socket of the teeth, conventional and digital radiographies were performed and the distance between the leveled cusp tip and the file tip were measured in conventional radiography and CMOS images by a caliper with an accuracy of 0.01mm and software, respectively. The data was analyzed using Greenhouse-Geisser, paired t-test and simple linear regression. Results: According to the findings of this study, there was no significant difference between the accuracy of conventional radiography and digital radiography (CMOS) in determining the working length of the root canals of mandibular first molar teeth with less than 25˚ curve (p>0.05). However, in roots with more than 25˚ curve, the working length of root canal was higher in the digital radiography (CMOS) compared to the conventional radiography (E-speed) (p=0.001and p=0.004, respectively). Conclusion: Based on the results of this study, it can be concluded that digital CMOS radiography can be used to measure working length of root canals with mild curvature. However, in teeth with high curvature, it would be better to use conventional radiography to estimate the working length. [ABSTRACT FROM AUTHOR]

Introduction: The most common morphology of mandibular molars is two roots and three root canals; nonetheless, unusual anatomic variations may exist. Case reports: This study reports two cases of mandibular first molars with a mid-mesial root canal that underwent treatment and follow-up in the Endodontics Department of Isfahan School of Dentistry. During the initial treatment, the mid-mesial root canal had not been detected in both cases due to the failure to prepare a convenient access cavity. Conclusion:Preparation of convenient access cavity, knowledge of canal anatomy and presence of uncommon variations should be more appropriately taken into account during the general training and systematic re-training programs of general dental practitioners. [ABSTRACT FROM AUTHOR]