Journal of Dental School
Year:2006 | Volume:23 | Issue:4 (66)|Papers Count:23

Background & Aim: The purpose of this scanning electron microscope (SEM) study was to compare the cleanliness of the root canal walls following either a manual or a rotary technique of canal instrumentation. The hypothesis was that a rotary technique would produce a cleaner root canal. Methods & Materials: Manual filing was performed on 24 extracted teeth with the curvature more than 20˚ using stainless steel K-flexofile (DENTSPLY MAILLEFER). Powered instrumentation was carried out on a further 24 extracted teeth, using Hero 642 (Micro Mega France) nickel-titanium files in a handpiece NSK (ENDO-MAT TC) (375 r.p.m) according to the manufacturer's instructions. A normal saline solution was used for irrigation. The roots were cut longitudinally and the canal walls were examined for debris and smear layer at the apical, middle and coronal level.Results: When using rotary technique, significant superiority was seen in removal of debris (p<0.05). But, the two groups didn't have significant difference with reference to smear layer. The three region examined in each group didn't have significant differences with regard to debris and smear layer.Conclusion: The rotary technique employed in this study produced cleaner root canal walls than the manual SS K-flexofile instrumentation.

Background and Aim: Abnormal occlusion is one of the most important etiologic problems in patients with dento - facial and cranio - facial abnormalities. In orthognathic surgery this parameter (occlusion) would become normal. Probably it is acceptable to correct the skeletal and occlusal problems to improve speech and articulation. This study was designed to evaluate the effect of orthognathic surgery on articulation and speech on 1999 in Taleghani Hospital.Methods &Materials: This clinical trial study was performed cross - sectionally on 18 patients that consist of 5 male and 13 females. All patients had dentofacial deformities. BSSRO osteotomy and bimaxillary ostetomy were performed on each patient to correct their skeletal deformities. There was no palatal defect or dentocranial problem, mental retardation and hearing problem in the patients. Phonetic test was done before surgery. This test was repeated 6 months after surgery. Findings before and after surgery were evaluated and data were compared with paired t-test. Results: Results showed significant changes after surgery which means these kind of surgery have a positive effect on speech and articulation.Conclusion: It seems an advantage to use orthognathic surgery with speech therapy to improving speech and articulation.

Background & Aim: Y axis angle is one of the measurements which is used in assessment of mandibular growth pattern. It seems, is not in coordination with the mentioned 66 degrees in texts and is more in our patients. Thus in this study, Y axis angle is measured in lateral cephalograms of over 15year old Iranians, to find if there is any difference.Methods & Materials: In this descriptive study, two hundred conventional lateral cephalograms were traced. Y axis angle and another angles showing vertical growth of mandible were measured. The cephalograms were divided in to three groups of horizontal and three groups of vertical growth. The difference between each three groups was assessed by ANOYA. The correlation between vertical angles was assessed by Pearson analysis. The mean of Y axis angle in 17-18, 19-20, 21-30 years old was compared with Bolton measurements by Hest. Results: Y axis was 68.83±5.34 in boys and 68.6±74.8 in girls. The difference was not statistically different. The difference between the vertical groups was significant (P<0.01).The difference between Cl III and Cl 11, Cl III and Cl 11 was significant (P<0.05). The correlation was strong between Y axis and GoGn/SN and sum of posterior angles (r=0.76) and moderate between Y axis and MPA angles (r=0.56). Conclusion: The most significant difference was seen in 17-18 year old girls (64.6±4)in comparison with Bolton study (67.2±3) (P<0.05). Bolton measurements can be used for other compared ages in both sexes. It is recommended to use standard deviation for 66° of Y axis, thus we would be able to apply it to larger populations.

Background & Aim: With regards to improvement in medical treatment methods for thalassaemic patients and demands for orthodontic treatment of this group, the present study was undertaken to compare cephalometric parameters of patients under regular treatment with those under irregular treatment and normal individuals with emphasis Mc Namara method.Methods & Materials: This cross-sectional study was performed on a total of 90 thalassaemic patients under regular on treatment, 45 males (mean age: 13.4 yrs.) and 45 females (mean age: 13.7 yrs.) as the study group, 80 thalassaemic patients under irregular treatment composed of, 30 males (mean age:13.2 yrs) and 30 females (mean age: 13.8yrs) and 90 normal individuals, 45 males (mean age: 13.4) and 45 females (mean age: 13.3 yrs) as the two control groups. Lateral cephalograms were provided for all subjects and cephalometric parameters defining craniofacial morphology, derived mainly from McNamara analysis, evaluating soft tissue, dental, dentoalveolar and skeletal characteristics were assessed. Analysis of variance (ANOVA) for comparing the 3 groups and T-test to identify the existence of any differences between 2 groups were used in this study. Results: All thalassaemic patients in the two groups had a Cl II skeletal base relationship especially those under irregular treatment. There was no significant difference between the mean of the most cephalometric parameters in the thalassaemic patients group under regular treatment with normal control group, while the statistical analysis showed significant difference (P<0.05) between most of the parameters in thalassaemic patients in the 2 groups. Vertically, the growth pattern of thalassaemic patients under regular treatment, differing much from those under irregular treatment, showed to be nearly similar as the normal individuals.Conclusion: The role of regular transfusion vs. irregular treatment of the thalassaemic patients is very important not only for longer life time, but it helps to attain normal facial appearance. The facial and skeletal pattern of thalassaemic patients with regular treatment differ much from those with irregular transfusion especially in vertical dimensions and dentoalveolar aspects.

Background & Aim: Mineral Trioxide Aggregate (MTA) is being widely used for root - end filling, pulp capping, perforation repairs, and other endodontic procedures. MTA, Portland cement (PC) and Root - MTA have many similar physical, chemical and biologic properties. PC has shown promising potential as an endodontic material in several in vitro and In vivo studies. The purpose of this study was to compare the cytotoxic effect of MTA, PC and Root- MTA on human peripheral blood mononuclear cells. Methods &Materials: In this experimental study three materials were inserted inside culture plates which contained human peripheral blood mononuclear cells. After 24 hr, the cell morphology and cell counts were studied. The viability of cells was also evaluated in 24 - hr. The results were analyzed by ANOVA and Kruskal Wallis and Mann Whitney - U statistical tests.Results: Statistical analysis revealed a significant difference between the toxicity of the test materials after 24-hr (P=0.025). The tests revealed that there was a significant difference between the cytotoxicity of MTA and Root - MTA (P=0.033), but there was no significant difference between MTA and PC (P=0.599).Conclusion: MTA and PC show comparable biocompatibility when evaluated in vitro unlike Root - MTA which exhibits a higher toxicity. The results suggest that PC has potential for use as a less expensive root - end filling.

Background & Aim: Main purpose of this cross sectional study was to assess the prevalence of DMFT among 100 mild mental retard (IQ=50-70) students 8-12 years -old from special Yazd schools. Methods &Materials: One hundred mild mental retardation children 8-12 years old (46 girl and 54 boy) were chosen from special Yazd schools and the data from the questionnaires were analyzed by computer, using the SPSS software.Results: The average of DMFT in 8 - 12 year - old special students was 5.95±3.83 (6.93±3.54 for girls and 5.1±3.89 for boys). Of the total DMFT obtained, 4.3 was ascribed to dental caries, 1.46 to extracted teeth due to caries, and the last 0.19 to restorated teeth. Ten percent of population was caries free and in twelve percent of population had DMFT more than 10.Conclusion: The results showed no significant difference between parent's education and the rate of dental caries in students. But there was significant reduction of DMFT in the students who brushed regularly (p-value=0.0001).

Background &Aim: Chronic liver diseases especially cirrhosis may cause different complications in patients, such as periodontal disease. The purpose of the present case - control study was to examine the effect of chronic liver diseases on the periodontium.Methods & Materials: The experimental group consisted of 60 patients with diagnosed chronic liver disease. 60 systemically healthy subjects formed the control group. Age, gender, level of education, socio- economic level and cigarette smoking were not statistically different between the two study groups. (P>0.05) The Ramfjord index teeth were recorded for plaque index (PI), clinical attachment loss (CAL), and gingival bleeding (GB).Results: CAL in the test group was significantly greater than the control group (P<0.05) which showed that the hepatic patients were 3.3 times more at risk of moderate to severe attachment loss than the healthy subjects (Odds ratio = 3.3), however, mean PI and GB were not statistically different between the study groups (P>0.05). Conclusion: Patients with chronic liver disease demonstrated more CAL than the healthy subjects with the same PI and GB. Thus liver disease might be assumed as a risk factor for periodontal diseases.  

Background and Aim: The important role of genetics has been recognized in recent years with respect to the understanding of tooth agenesis (TA). Identification of genetic mutations in individuals with tooth agenesis or other dental anomalies will enable preclinical diagnosis and improves orthodontic treatment. The aim of the present study is to assess the relationship between T.A and MSXI mutation.Methods &Materials: Case group consisted of 20 individuals with T.A and control group consisted of 20 individuals with complete set of dentition. Blood samples were collected and DNA's were extracted with P.C.I Ext Method. DNA's were amplified with PCR technique and after addition of Ban II on PCR product, presence or absence of MSXI mutation was evaluated. Evaluation was based on presence of additional DNA band in gel of electrophoresis in case group. Chi square test was used to compare two qualitative traits. Results: Ban II had no effect on DNA of control group (195 bp) and digested the defected Allele in case group (106 bp and 89 bp.) (P-valve <0/001).Conclusion: In control group no mutation had occurred and all of individuals in case group, had heterozygous mutations and there is a high significant statistical relation ship between T.A and MSXI mutations. Given the absence of tooth follicle in dental radiography, formation or agenesis of the mentioned tooth can be determined by means of explained method of present study. After all, performing a blood test can prognosticate whether the future tooth can be developed or not.

Background & Aim: According to high prevalence of caries in occlusal surfaces of teeth in children and adolescents, use of fissure sealant materials has been recommended for many years. In sealant-therapy, improvement of adhesion and ease of handling is important and noticeable particularly impossible isolation situation. The aim of this study was to evaluate the effects of self- etching primer (SE Primer) conditioner and saliva contamination on microleakage of RMGI as sealant.Methods & Materials: In this in vitro and experimental study, 160 human maxillary sound extracted premolars were selected and randomly divided randomly to 8 groups with 20 teeth in each group. Then sealant was applied on them using the following techniques:1) Conditioner, Primer + RMGI - 2) Conditioner + RMGI - 3) Conditioner, Saliva + RMGI - 4) Conditioner, Saliva, Primer+ RMGI- 5) RMGI alone- 6) Saliva, Primer+ RMGI- 7) Primer+ RMGI- 8) Saliva+RMGI. After thermocycling (500 cycles) and immersion in %0.5 basic fushion, the teeth were sectioned and evaluated for dye penetration by stereomicroscope (x12) (0-4 scale). Statistically analysis was done by nonparametric test (Kruskal - Wallis).Results: The results showed that the microleakage is significantly increased by saliva contamination. As well using conditioner or primer 'alone, has significant effect on reducing microleakage of RMGI, but simultaneous use of primer and conditioner in a situation without saliva contamination can increase microleakage. With Saliva contamination, using the primer can reduce micorleakge.Conclusion: On the base of this study, using the acidic primer prior to applying RMGI on either isolated condition or saliva contamination can reduce microleakage significantly.  

Background & Aim: Quality of life (QOL) is a state of well-being in which the individual is able to perform everyday activities related to physical, psychological, and social well-being and patient satisfaction with function and/or control of disease and/or treatment of symptoms. This study reviews the literature regarding the development and use of these oral health related QOL. In modem medicine, the traditional way of assessing change in patients has been to focus on laboratory or clinical tests. While these give important information about the chronic and progressive diseases, it is impossible to separate disease from an individual's personal and social context. No illness exists in a vacuum. One way of capturing the personal and social context of patients is to use quality of life measures. These measures give the possibility to express subjective changes in wellbeing to patients. These are accepted as outcome measures in clinical research but are rarely used in routine clinical practice. In dentistry, as in other branches of Medicine, it has been recognized that objective measures of disease provide little insight into the impact of oral disorders on daily living and quality of life. A significant body of development work has been undertaken to provide health status measures for use as outcome measures in dentistry.Conclusion: It has been shown that socioeconomic status; oral health behavior and oral health status each influence oral quality of life.

Background & Aim: Acrylic resin is a thermal consulator which is a great disadvantage for this material. In some studies Al2O3 is added to polymethyl methacrylate to improve its thermal conductivity. The purpose of this experimental study is evaluation of some physical properties of the acrylic resin mixed with Al2O3, such as transverse strength, transverse deflection, modulus of elasticity and hardness. Methods & Materials: Three groups of acrylic resin (Meliodent, Bayer UK heat cure acrylic resin) each consisted of 20 specimens were prepared. The first group was control (pure acrylic resin), the second group was PMMA specimens with 15% (weight percentage) Aluminum oxide powders (Martinswerk, Germany) and the third group was PMMA specimens with 20% Aluminum oxide. The transverse strength, transverse deflection and modulus of elasticity were measured by use of universal testing machine (Dartec) and the dimensions of specimens were 65×10×2.5mm loading speed was 1mm/min. Hardness was measured by use of Brinel hardness tester machine. The dimensions of specimens were 20×20×5 mm. Analysis of variance and Duncan test were used for data analysis. Results were based on Mean±standard deviation.Results: There was a significant difference between the mean of transverse deflection between control group and test groups (p.v=0.004). But Duncan test revealed that there were not significant differences between the test groups. The mean of modulus of elasticity of test groups and control had significant differences (p.v=0.007) but Duncan test showed no differences between test groups. The mean of transverse strength and hardness of groups showed no differences.Conclusion: This study showed that the mixing of Aluminum oxide and acrylic resin, decreases transverse and deflection strength and increases modulus of elasticity of modified resin but it has no effect on resin hardness.  

Background and Aim: Lymphoma is the seventh malignancy in human which can be presented in oral cavity or as a cause of cevico-facial lymphadenopathy. Because of different epidemiologic characteristics of lymphoma in geographic area, this study designed to determine epidemiologic indices and frequency of oral and cervicofacial manifestations of lymphoma in patients referred to Dr. Shariati Hospital and a private clinic in Tehran in 1381.Methods & Materials: In this cross - sectional descriptive study with simple sampling the age, gender, type of lymphoma, clinical and histological category, site and type of oral and cervico-facial lymphnodes lesions, and paraclinical examination are determined.Results: Four hundred twenty five patients were studied including 182 Hodjkin cases with mean age 31.2±14.5 (male to female ratio = 1.6) and 243 non - Hodjkin (NHL) cases with mean age 41±16.1 (male to female ratio = 2.2). The most common features were mediastinal and pulmonary lymphadenopathy and then cervical lymphadenopathy in HD cases and cervical lymphadenopathy in NHL patients. Submandibular lymphadenopathy (%3.8) without oral lesions in HD and submandibular lymphadenopathy (11%), submandibular and sublingual salivary glands lesions (%1.6) and tonsilar enlargement in NHL cases has been showed. Nodular sclerosis was the most common type of histopathologic finding.Conclusion: High frequency of cervical lymphadenopathy in HD and NHL cases with oral lesions in 0/04.5 of NHL notifies us the importance of complete dental and oral examinations.  

Background & Aim: The purpose of this study was to compare the effect of sandblasting on shear bond strength of three metal brackets.Methods & Materials: For this experimental study, 180human maxillary and mandibular first and second premolars teeth obtained from orthodontic patients were cleaned and stored in 0.1% thymol solution. The teeth randomly assigned to either the control (n=90) or experimental (n=90) groups. Each group subdivided into three equal groups (n=30). In control groups, three different non - sandblasted metal brackets (3M Uniteck, Dentaurum and Am orthod) were bonded with 3M (Unitek) no - mix resin. In the next stage of experiment, similar brackets were sandblasted and used. All samples pumiced and were etched with 37% phosphoric acid (3M unitek) for 15 seconds. The teeth were embedded in blocks of autopolymerization polymethyl methacrylate (2×2×3 cm), using a special device to make their slots parallel to horizontal plane. Samples were stored in distilled water at room temperature for 24 hours before testing. Testings were performed with an instron machine. The data were analyzed by ANOVA, LSD, Kruskal- wallis and Man - Whitney tests.Results: In non-sandblasted groups, the results were analysed by ANOVA and LSD non-comparisons tests. In sandblasted groups non-parametric tests including Kruskal- wallis and mann - whiteny used for statistical analysis. For evaluating each pair bracket type untreated and sandblasted, Levene and t - test analysis were used. Mean shear bond strength of untreated groups were 15.51, 16.60, and 18.58 Mpa for Am Orthod, Dentaurum, and 3M Unitek companies respectively. Mean shear bond strength of sandblasted groups were 15.18, 19.38, and 18.66 Mpa for Am Orthod, Dentaurum, and 3M Unitek companies respectively. Increase in shear bond strength of Dentaurum brackets was statistically significant, but was not significant for 3M brackets.Conclusion: Sandblasting usually increase shear bond strength in metal brackets. In specific circumstances that, extra shear bond is needed, bracket sandblasting could be used according to the manufacturer instrumentation, combined with chemical adhesion promoters.

First permanent molars play key role in the dentition. Because of deep occlusal fissures from one hand, and the neglect of their presence in the mouth by child and parents from the other hand, they are affected by cariogenic agents more than any other tooth, which results in extensive caries, followed by extensive fillings with recurrent caries in some cases, and sometimes, their conditions are so that causes pulpal involvement or abscess, and make the treatment difficult. These conditions cause a poor prognosis for first permanent molar and put into consideration their restoration or extraction.This article with the aid of available references assesses the details of the possible conditions involved in decision on restoration or extraction of first permanent molar with poor term long prognosis. In general, the ideal time for extraction is between the ages of 8.5 - 10.5 years old and from developmental aspect, beginning of the beginning root formation of second permanent molar and Cl I occlusion with mild crowding. In the cases of Cl II or Cl III malocclusion, consultation with orthodontists is necessary.

Background & Aim: Vital bleaching agent could effect on physical and mechanical properties of teeth. The purpose of this in vitro study was to evaluate the effect of different concentrations of vital bleaching agents on the flexural strength of enamel and dentin complex.Methods & Materials: This in vitro study was an interventional with a parallel design. 2×3×8 mm beams were cut from facial surface of previously extracted bovine incisors. The dentinal part of the teeth was covered by wax. The specimens were divided into four groups of 12 based on the kind of bleaching agent. Group A) 9% Perfecta Bravo, Group B) 15 % Opalescence, Group C) 20% Opalescence and Group D) Control. The experimental groups were immersed in vatial bleaching agent for a period of two weeks according to the instruction of manufacturer. The control group was immersed in synthetic saliva. Flexural testing was performed 24 hours after the last treatment using an Instron testing machine with a crosshead speed of 0.2 mm/min. The results were analyzed by one way ANOVA (a= 0.05).Results: The mean of data (Mpa) were A: 123.99, B: 124.87,C: 162.98 and D: 141.26.After using a nonparametric analysis Kolmogrov - Smimov for acceptance of normal assumption (a=0.05), one way ANOVA showed that there was no significant difference among groups (P>0.05).Conclusion: Different concentration of bleaching agents had no significant effect on flexural strength of enamel and dentin complex.

Background & Aim: Squamous odontogenic tumor (SOT) is a rare benign neoplasm with dental origin first described in 1975. Fewer than 40 cases had been reported till now. The SOT may have been originated from epithelial rests of Malassez, but it is suggested in some cases of embeded teeth they may arise from epithelial rests in dental follicle.The purpose of this case report is to show the rarity of this neoplasm and its importance in similarity with acanthomatous Ameloblastoma and well differentiated squamous cell carcinoma.Case Report: The patient is a fifty - four year old man who was referred to surgical department of Mashhad Dental school on July 26, 2003 with buccal expansion and tenderness in right premolars and first molar of mandible. He gave a history of swelling and tenderness at this site for twenty - two years. No significant finding was detected in his past medical history.In clinical examination, buccal expansion in right premolars and first molar of mandible and teeth mobility with moderate periodontitis were observed.Under local anesthesia partial biopsy of the lesion was taken. On microscopic examination, this lesion was diagnosed as SOT. Through next surgical procedure, exisional biopsy and bone curretage was performed (his anterior teeth were also extracted to his own will). Microscopic examination of exisional biopsy confirmed SOT.Conclusion: SOT is a rare neoplasm and this case is the first sample which identified from the beginning in Mashhad dental school up to now.

Background & Aim: To determine the bond strength of four adhesive systems to either superficial or deep dentin.Methods & Materials: Eighty- eight extracted human impacted third molars had their crowns transversally sectioned either next to the occlusal DEJ or 1 mm above of the CEJ, to expose flat, superficial or deep dentin surface. The surfaces were bonded with: 1) Clearfil SE Bond (CSEB), 2) Single Bond (SB), 3) Scotch Bond MP (SBMP) and 4) Prompt L-POP (PLP) according to manufacturer's instruction. Composite build-ups were constructed incrementally with Z100. After storage in 25°C water, teeth were thermocycled. Then instron machine was used to measure the shear bond strength of each specimen with cross head speed of 1mm/min. One way ANOVA and Tukey test were used to analyze the data.Results: Bond strength of SB, SBMP & SCEB performed equally when were bonded to superficial dentin; lowest value was obtained with PLP. On deep dentin, the bond strength of CSEB was significantly higher to superficial than to deep dentin. The rest of the adhesives showed almost similar bond strengths to both dentinal depths.Conclusion: CSEB & SBMP showed higher bond strength on both deep and superficial dentin. So, in regards to the results of this study, using these bondings in deep dentin areas is recommended.

Background & Aim: The aim of this study was to evaluate the success rate of treatment of gingival melanin pigmentation by cryotherapy wing liquid Nitrogen.Methods & Materials: In this clinical trial. 20 healthy mature patients (10 males and 10 females) were participated. Since gingival pigmentation often occurs as diffuse bilateral discoloration; therefore, one side was used as case and the other side as control. Treatment was carried out by liquid nitrogen and a cotton suab. Patients were followed up for six to twenty months and comparison was made between case and control sides. Comparison was both measured in qualitative and quantitative methods. For qualitative measurements, three assessors performed the measurements and for quantitative method, RGB and CMYK color analysis of Photos hop software were used to compare the two sides.Results: The result of qualitative method indicated that in all of patients, the case and control sides were different. In 40 percent, the difference was great, in 50 percent the difference was moderated and in la percent the difference was low. The results of RGB and CMYK color analysis demonstrated that in case group red, blue, green, black and, colors was obviously brighter than control group. Conclusion: Cryotherapy is a successful and effective treatment to remove gingival melanin pigmentation.

Background & Aim: To determine the prevalence of oral soft tissue (OSTLs) in elderly institutionalized population and comparison the frequency of these lesions between private and governmental institutes. Methods &Materials: Three hundred and forty three persons aged over 60 years, residing in institutes in Tehran were studied in a descriptive study. Among them 158 persons were resided in government institutes (GIs) and 185 persons were resided in private institutes (PIs). This population was selected by census in GIs and by a cluster sampling in PIs. Demographic variables and previous medical conditions were recorded in a questionnaire according to the patient's statements and by using medical files. The selected ones were visited by a dentist under focus light with proper instruments. Biopsy was carried out if necessary. Results were analyzed by Chi Square and Fisher's exact tests as indicated. All tests were 2-tailed and were set as 0.05.Results: A totally 117 individuals (74.1 percent) in GIs and 149 individuals (80.5 percent) in PIs had at least one OSTL. There was no statistically significant difference between two groups (P=ns). The most common lesions were fissured tongue (50.6 percent), candidiasis (18.4 percent), atrophic glossitis (17.5 percent), denture-induced stomatitis (12.2 percent), sublingual varicose (11.7 percent), and angular chelitis (9.6 percent). The frequency of denture-induced stomatitis, fissured tongue, angular, epolis fissuratum and candidiasis were higher in PIs than GIs (P<0.05, P<0.001, P<0.05, P<0.01 and P<0.05 respectively). However, there was a higher frequency of mucosal pigmentations, sublingual varicose and fibroma in GIs than PIs (P<0.01, P<0.05 and P<0.05, respectively).Conclusion: This study revealed that prevalence of OSTLs is equal in elder individuals resided in Gls and PIs.  

Background & Aim: Due to the great influence of impression techniques on dimensional accuracy of implant master casts and existence of controversy about the best impression technic, this study aimed to evaluate the influence of four impression techniques on dimensional accuracy of implant's master cast. Methods & Materials: In this experimental study, five implant's analogues on laboratory models was used to transfer the positions of implants with four impression techniques. For each impression technique, 4 master casts was made. Impression techniques used included: I - non splinted + perforated tray, 2- non splinted + open tray, 3- splinted + open tray, 4- splinted + perforated tray. Dimensional accuracy of master casts fabricated with different impression techniques, was evaluated with comparison of distance of indicated points on the implant's analogues between laboratory model and master casts. The distance between points was calculated on 3 axis (X, Y, Z) and special position of points was also calculated. This evaluation was calculated with micrometer in precision of I micron. Data were evaluated with SPSS software and Repeated Measure analysis.Results: Significant difference was not found between the influences of four impression techniques on dimensional accuracy of implant's master casts. None of the four impression techniques didn't transfer precisely the location of indicated points of laboratory model to master casts on X, Y, Z axes or spatial position of them.Conclusion: Acrylic resin splinting didn't show significant influence to augment the dimensional accuracy of master casts, so the non splinted technique is advisable because of simplicity and economic. Although more investigations is needed in this issues to augment the dimensional accuracy of master casts and approach to oral situation for increasing the clinical relevance.

Background & Aim: Different and contradictory results are concluded in studies conducted about the effect of different antiseptic solutions on post surgery infection rate and pain intensity. So, this study was performed to compare Betadine and normal saline in reducing complications after the surgical removal of impacted third molars in dental socket irrigation.Methods & Materials: The study was performed experimentally. A group of 42 patients, referring to Tehran Milad Hospital dental unit and a private clinic, were selected sequentially for the purpose. The impacted third molars were extracted by means of a clinical indication. One side of the socket was irrigated with Betadine solution when the opposite side was irrigated with normal saline, comparing the infection rate and other post- surgical complications at two sides. Quantitative variables such as age and number of the sutures along with qualitative variables such as gender, pain, swelling, infection, dry socket and etc, were assessed. Statistical software of SPSS for windows was used for data analysis, using student t - test for quantitative and chi -square test for qualitative variables as statistical tests in order to compare the sides. Results: The age of the patients was 24.3±7.8 years, 13 individuals (31%) were males while the next 29 individuals (69%) were females. There was no statistically significant difference between two sides irrigated with normal saline and betadine considering intensity of pain, swelling, infection and dry socket. Conclusion: The study revealed no significant difference between number of sutures used in both sides, verifying the correctness of the study. No significant difference between all factors at both sides resulted in this study had been reported in other studies. Complications such as allergy, stimulation, mucosal redness, itching, subsequent sense of heat and possible burning associated with the use of betadine suggests the use of normal saline in minor teeth and oral surgery for irrigation.