Journal of Dental Medicine

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Normal 0 false false false EN-US X-NONE AR-SA In order to evaluate occupational health in dentists of Tehran, 250 dentists ( 60f/190m) were selected. The results of our survey showed significant hearing loss in both ears of all the dentists mostly in 6 ghz frequencies. Urine analysis showed higher mercury levels in general practitioners than specialists Although this was not statistically significant. The majority of dentists refused to reply questions about occupational diseases. Only the younger generation of them with working experience of 5-9 years replied to all the questions of questionnaire.

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Anterior tooth crown fracture in children is something that each dentist will confront many times during his professional career.We studied the prevalence of anterior teeth crown fractures between 7-14 years old students in Tehran and some relevant factors like sex, age, the traumatized tooth, amount of overbite and overjet, upper lip coverage, jaw that had fractured tooth or teeth and place of fracture in fractured crown.1338 boys and 1184 girls were in this study. Tooth fracture was almost the same in boys and 1184 girls with the prevalence of 8%. Fracture was mostly in enamel and average year of fracture was 10 years.Increased overjet and overbite had direct relation and indirect relation with fracture, also enough lip coverage showed less fracture.

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Composite resin restorative materials, that nowadays are used as tooth-colour materials, have both benefits and weaknesses. One of these weaknesses is the contraction resulted from resin polymerization which influences on the composite dentin bond strength and it has been tried to be eliminated by different bonding systems. The aim of this in-vitro study was to compare the dentin bond strength of two dentine adhesive systems: multi-step Scoth Bond Multipurpose (SBMP) and single- step Excite, by two composites of Ideal Makoo and Tetric. One hundred sixty (160) sound human molars were selected. At first they were debrided and mounted with acrylic resin in molds. The enamel of the buccal surface was eliminated by diamond burs. To provide a flat dentin surface, it was removed about lmm. Then, based on the type of dentin adhesive, they were divided into two groups of 30 teeth and were applied on the exposed dentine surface according to the manufacturer's instructions. Then, each group was divided into two subgroups of 15, based on the type of composite resin. Cylinders of the desired composite resin, attached to the dentin surface, were used for 80 seconds. The samples were stored in 100% humidity (37°c) for 24 hours. The bond strengths was measured by a cross head blade with the speed of 2mm/min. Variance analysis and Duncan test, with 95% confidence level, showed that statistically, two factors of adhesive and composite, interact on each other, in bond strength. There was no significant difference in bond strength, between two composites with similar adhesives, however, comparing two different adhesives with the same composite, showed that the bond strength of Tetric with Excite (28.39) was more than that of SBMP (17.98 Mpa). Finally, it was recognized that among four experimental groups, there was only a significant difference in bond strengths, between Tetric-Excite with Tetric- SBMP. This study shows that dentin bond strength is influenced by dentin bonding agents, composite type and dentin structure, and using a type of composite with a dentin bonding agent, manufactured by the same company, results in a higher bond strength.

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Statement Problem: A few studies have been conducted about bioglass posts.
Aim: The aim of this study was to compare bioglass posts with prefabricated metallic posts in clinical performance of extensive composite restorations for anterior endodontically treated teeth.

Materials and Methods: Sixty endodontocally maxillary anterior teeth, with horizontally or vertically destruction, were selected. Teeth were divided into two groups based on the kind of post: Metallic prefabricated parapost and bioglass post. Each group was divided into three subgroups based on anterior bite: normal, deep bite and edge to edge. Gutta-percha was removed from 2/3 of canal length for parapost and 1/3 for bioglass post. After etching with phosphoric-acid (37%) and applying dentine bonding syntac, Duo cement was used for the adhesion of bioglass post and a self cured composite (Degufil) for parapost. Restoration was done with a hybrid composite (Heliomolar). Follow up studies, radio-graphically and clinically, were done every three months for a 1.5-year period. Exact Fisher and Pearson tests were used for data analysis.
Results: Apical lesion was not observed in any of the radiographs. Post seal was increased by resin cement and dentin bonding agent. Post type did not significantly affect on the clinical success rate of the restorations. The retention of restoration, for both posts, was the same. Crown destruction had no significant effect on success rate. The type of anterior bite had a significant effect on success rate, as the total 6.6% failure rate was related to the patients with anterior deep bite.
Conclusion: It is suggested to use metallic paraposts and bioglass posts, in extensive composite restorations for patients with deep-bite, more conservatively.

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Statement of Problem: A lot of efforts have been made to create a complete adaptation between tooth and amalgam restorations.
Purpose: The aim of this study was to evaluate microleakage and interfacial micromorphology of amalgam restorations lined with dentin adhesives, namely One Coat Bond, Syntac, Excite and Copalite,as liners.
Materials and Methods: 144 intact human canine teeth were selected. Then class V cavities, with enamel and dentinal margins, were prepared on each of them. Cavities were lined with different dentin bonding systems (Syntac, One Coat Bond and Excite) according to the manufacturer's instructions and restored with Oralloy and Cinalloy, non gamma 2 spherical amalgams and Aristaloy a non gamma 2 Admixed alloy. Copalite was used in the group, served as controls. After thirty days storage in synthetic saliva at 37°c, the specimens were thermocycled in saliva (4000 cycles). The degree of microleakage was assessed by means of basic fushin dye penetration and recorded. The gap width was evaluated with Scanning Electron Microscope. Pearson and %2 tests were used to analyze the results.
Results: None of the systems, tested in this study, eliminated microleakage completely, Pearson's correlation coefficient showed a positive correlation between gap and microleakage (P<0/05).Statistical significant differences were revealed among the liners regarding gap and microleakage (P<0.05).One Coat Bond and Syntac appeared to leak less than other groups. The gap width by One Coat Bond and Syntac were respectively 0.35 and 0.3 urn in dentine, 0.2 and 0.1 in enamel. Excite and copalite gap width in dentine and enamel were 1,3-1.36 urn and 0.3-0.6, respectively. The type of amalgam did not have any effect in the degree of microleakage and gap width (P>0/05).
Conclusion: One Coat Bond and Syntac, comparing to Excite and Copalite, showed less microleakage and gap width.

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Statement of Problem: Parafunctional habits are the most important factor in the creation of non-carious cervical lesions and correcting of these habits may affect cervical lesions.

Purpose: The goal of this study was to survey the effects of one-year occlusal adjustment on clinical success of non- carious cervical restorations.

Materials and Methods: In this clinical study, sixty tooth-colored cervical restorations on canines and premolars in patients with parafunctional habits (bruxism and clenching) were studied. The teeth, according to the type of restorative material, were randomly divided into two groups: One group with a composite resin (Tetric Flow Group A: n=30) and the other group with a compomer (Compoglass Flow Group B: n=30). After restoration, each group was divided into two subgroups: (A1, B1) with occlusal adjustment (case group), (A2, B2) without occlusal adjustment (control group). The evaluation was perfumed single blind at 6 and 12 months after restorative operations according to Us Public Health Service (USPHS) classification. Assessment criteria included: marginal integrity, marginal discoloration, recurrent caries, postoperative sensitivity and loss of filling. Statistical analysis was completed using Fisher’s exact test.

Results: In 12 month period between two groups of compoglass Flow restorations, group B1 showed superior results than group B2, however, no significant difference was found between both groups of tetric flow restorations (A1 and A2). There was also no difference in clinical conditions between A2 and B2 groups.

Conclusion: Considering the results of this study, it can be concluded that occlusal adjustment puts a considerable effect on clinical success of compoglass non- carious cervical restorations. However, it should be mentioned that such and effect was not found among Tetric flow restoration.

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Background and Aims: Intrabony periodontal defects are one of the important problems in periodontal diseases. Treatment of intrabony periodontal defects with synthetic materials such as Cerasorb has been shown to enhance periodontal regeneration. The aim of this study was to compare the effect of Cerasorb with autogenous bone graft (A.B.G) as a gold standard in treatment of two to three wall periodontal defects.
Materials and Methods: In this interventional or randomized clinical trial study, 24 two to three wall intrabony defects were selected in a double blind manner. Defects were randomly (with tossing a coin) divided into two groups (test and control). Defects in test group were treated with flap surgery and Cerasorb. In control group, defects were treated with flap surgery and autogenous bone graft. At baseline and 3-month, 6-month and one-year follow up evaluations clinical and radiographic assessments were performed. Data were statistically analyzed using the paired t test, Wilcoxon and Mann-whiteny. The level of significance was set at P<0.05.
Result: At the 3-month, 6-month and one-year visits, the parameters of probing pocket depth (PPD), probing attachment level (PAL), bone level (distance between CEJ and alveolar crest), and bone density were not significantly difference in test and control groups (P>0.05). However, in each group there was significant difference in 4 parameters before and after surgery (P<0.05).
Conclusion: Treatment with Cerasorb compared to A.B.G produced the same results of improvement in two to three-wall intrabony defects. So the use of Cerasorb can be suggested for treatment of intrabony periodontal defects.

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Background and Aims: The aim of this in vitro study was to compare shear bond strength of metal brackets bonded to dental porcelain on the basis of presence or absence of silane, type of acid [hydrofluoric acid (HF) or phosphoric acid (H3PO4)] and roughness of porcelain surface (glazed or deglazed) within mouth-like environment.
Materials and Methods: Eighty glazed ceramic disks were randomly divided into 8 groups of 10 disks: group 1 [HF+silane], group 2 [deglazed+HF+silane], group 3 [HF], group 4 [deglazed+HF], group 5 [H3PO4+silane], group 6 [deglazed+H3PO4+silane], group 7 [H3PO4], group 8 [deglazed+H3PO4]. Then the brackets were bonded and thermocycled. After that, shear bond strength test was done using the Zwick device and the type of bond failure was determined under stereomicroscope at 4X magnification. 3-way ANOVA and Kruskal-Wallis were used for statistical analyses.
Results: The shear bond strength for the test groups were as follows: group (1):13.05±7.7 MPa , group (2):25.16±10.66 MPa, group (3):6.7±5.86 MPa, group (4):15.39±8.97 MPa, group (5):12.76±7.91 MPa, group (6):13.57±7.85 MPa, group (7):0.54±0.67 MPa, group (8): 9.34±6.52 MPa. The type of bond failure in all groups was adhesive failure except for group 2. No significant difference in the interaction between (glazed or deglazed), (presence or absence of silane), and type of acid was found (P>0.05).
Conclusion: Under the conditions of this study, the best clinical method was the use of 37% phosphoric acid and silane that resulted in the optimal clinical strength and adhesive bond failure.

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Background and Aims: The aim of this study was to evaluate the quality of an experimental hydrofluoric acid (HF) for preparation of porcelain and to compare it with two commercial hydrofluoric acids in Iranian trademark.

Materials and Methods: A- Evaluation of etch pattern of experimental HF using scanning electron microscope (SEM): 6 feldespathic discs were divided into 3 groups. Each group was etched with related HF (experimental, Ultradent and Kimia) for 1 minute. SEM images were recorded at 3 magnifications. B- Bond strength test: 18 feldespathic discs were considered for each acidic group. Then the porcelain surfaces were etched and bonded to composite with unfilled resin. Consequently, the microshear test was done. C- Microleakage test: 54 discs were divided into 3 groups (n=18). Then the porcelain surfaces were etched and bonded to composite with unfilled resin and finally observed under stereomicroscope. The data were analyzed with one-way ANOVA and Smirnov tests.

Results: SEM analysis showed no difference between groups in terms of etch pattern. Microshear bond strength values for experimental, Kimia, and Ultradent HF were 28.53 (±4.92), 28.21 (±6.61), and 26.14 (±7.61) MPa, respectively. There was no significant difference between the bond strength of test groups (P<0.05). Furthermore, no significant difference was found between the microleakage of test groups (P>0.05).

Conclusion: Quality of experimental HF in terms of etch pattern, microshear bond strength and microleakage of composite/porcelain interface was similar to that of two commercial hydrofluoric acids.

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Background and Aims: The aim of this in vitro study was to assess the shear bond strength of amalgam to dentin using four dentin adhesive systems.
Materials and Methods: One hundred human molars were selected. After enamel removal, a dentin cylinder with 3 mm thickness was prepared. Eighty specimens were resorted with amalgam and four dentin adhesive systems as follows (n=20): group 1, Scotch Bond Multi-Purpose group 2, One Coat Bond group 3, PQ1 and group 4, Panavia-F. In group 5, 20 specimens were resorted with amalgam and varnish as control group. The specimens were incubated at 37°C for 24 h. The shear bond strengths were then measured by using push out method. The data were analyzed by one-way ANOVA and post hoc Duncan's tests.
Results: Mean values for bond strengths of test groups were as follows: group 1=21.03±8.9, group 2=23.47±9, group 3=13.16±8.8, group 4=20.07±8.9 and group 5=14.15±8.7 MPa±SD. One-way ANOVA showed the statistically significant difference between the bond strengths of five groups (P=0.001). Post hoc Duncan's test showed significant difference between groups 1and 3 (P=0.008), groups 1 and 5 (P=0.019), groups 2 and 5 (P=0.0008), groups 4 and 5 (P=0.042), and groups 3 and 4 (P=0.018).
Conclusion: Results of this study showed that the bond strength of amalgam to dentin using One Coat Bond as dentin adhesive system was higher than that observed in other dentin adhesive systems.

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