Journal of Dental Medicine

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The microleakage of Cinaally amalgam, manufactured by Dr Faghihi Co. which is a high copper alloy and fine-cut amalgam was evaluated by radioisotope agents. The microleakage of cinaally amalgam was compared with Sybraloy amalgam, manufactured by Sybron/Kerr Co. which is a high copper alloy and spherical shape amalgam and is known as a standard amalgam alloy. The results showed that there is no statistically significant difference between microleakage of them after 24 hours, one month and two months.

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Carious lesions are usually found by dentists, using bitewing radiographs, and according to the depth of the lesions, the treatment plan is designed. At the present, this technique is the most accepted one and is used generally. But it is not a perfect technique and there are some errors in determining of depth of proximal carious lesions. These errors are mainly related to the use of new high-speed films with broad density and lower voltages. In this study, dentin thickness under proximal caries in bitewing radiography was compared with its real thickness, in tooth structure. Twenty-four teeth samples with proximal caries were used. Before and after removal of carious lesions bitewing radiographs were taken and then each tooth was sectioned occlusogingivally and the thickness of dentine under proximal caries and on bitewing radiographs were measured under microscope with 0.01 mm accuracy. Mean value of dentine thickness in tooth structure was 41% of its mean thickness in bitewing radiographs, showing 59% difference (reduction). Therefore, more care should be taken in using standard technique and interpreting of bitewing radiographs by clinicians. Clinical examinations also should be performed in ideal conditions, and patients should be clinically and radiographically examined every six months.

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Background and Aim: The structural rehabilitation of a pulpless tooth is critically important to ensure a successful restorative outcome following endodontic treatment. A post and core is often indicated for the retention and reinforcement of the final restoration. But, the clinical situation is significantly challenging if the root exhibits immature development or there is a thin root wall that can compromise the prognosis for a long- term successful treatment. The purpose of this in vitro study was to evaluate different methods of intraradicular reinforcement in structurally compromised roots.

Materials and Methods: In this experimental study, seventy two extracted intact maxillary central incisors with similar size, shape and root anatomy were selected. After root canal therapy in 60 teeth, an acrylic laboratory bur was used to thin the cervical area and simulate the thin dentinal walls of immature teeth. The preparation was performed through the palatal access and extended 5mm apical to CEJ. The remaining 12 teeth remained unprepared to serve as positive control group. Cases were randomly divided into six groups of 12 teeth each and restored as follows. In the 12 cervically unprepared teeth (positive controls) the composite resin with dentin bonding agent (DBA) was placed in access cavity and cured for 120 seconds. This technique was also applied to other groups when the access was restored with composite. In the second group, the access cavity was restored with composite only to the level of CEJ. In the third group the cervically prepared teeth were reinforced with cement resin (Enforce) and a prefabricated post was placed in 5mm apical to the CEJ. In the fourth group, the cervically prepared teeth were reinforced with composite resin and DBA by a clear plastic post. In the fifth group the cervically prepared teeth were reinforced with composite resin and dba and a cast post. In the sixth group the cervically prepared teeth were restored with composite resin and dba with a prefabricated post. All of the specimens were mounted by rubberized technique and tested in the Instron universal testing machine. The fracture loads in samples were analyzed with ANOVA and Duncan tests with p<0.05 as the limit of significance.

Results: Significant differences in fracture resistance were observed between the first and second groups compared with others. The highest fracture resistance values were recorded for first group while the lowest were registered for the second group. Fracture resistance of the third, fourth and fifth groups had no significant statistical differences with others and fracture resistance of sixth group was the highest with significant difference (P<0.05).

Conclusion: From this study, it may be concluded that the use of a dba and a composite resin in thin-walled roots reinforces the immature teeth and facilitates the use of post.

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Background and Aim: By definition, pontic is an artificial replacement of missing tooth (teeth) which is essentially used to establish function and esthetics. In order to this fact that, pontic(s) is not completely the same as tooth (teeth) to be replaced, it may not be concern as a simple type of restoration to achieve the best result, it must be design from the esthetically and hygienically point of view as well as comfort, demand and tissue health of patient. The main purpose of this study is to investigate the pontic designs and their relationship to edentulous partial aras.

Materials and Methods: 73 pontics in 57 patients have been included in this cross-sectional study. These patients were under treatment in the department of prosthodontics. A primary cast was achieved from each patient and then the cross-sectional contour of edentulous ridge was depicted. For each patient the type of pontic design was derived from textbook standards and then compared with the design of actual verified Prosthesis at delivery. The shape of tissue surface of each denture was determined by a low viscous impression material. The result of each comparison was recorded in a chart data set.

Results: The most common pontic design was Modified ridge lap with frequency of 93.2%. The type of ridge was %45.2 normal, %19.2 class I, %8.2 class II and %27.4 class III, respectively. %72.6 of pontics tested have inappropriate design in tissue surface.

Conclusion: It seems that in a high percentage of cases the tissue surface contour of prescribed pontics in department of prosthodontics was incorrect and more attention must be paid to the education of students and technicians.