Journal of Dental Medicine
Year:2006 | Volume:19 | Issue:3 (48)|Papers Count:17

Dental portraits are predominantly used for orthodontics, orthognathic surgery and prosthetic dentistry. If these images are to be used for documentation, then the patient must be positioned in accordance with strict guidelines for further references. If the images are to be used to present an aesthetic impression of dental treatment there is more flexibility in positioning the patient. Dental photography is used to make pictures of teeth and surrounding tissues, radiographs, casts and other objects. In this section, standard principles for portrait pictures are explained.

Background and Aim: Intrabony periodontal defects are important problems in periodontology and up to now several ways have been suggested for their treatment. Treatment with enamel matrix derivatives (EMD) has been shown to enhance periodontal regeneration. There is limited information available from clinical trials regarding the performance of EMD in the treatment of periodontal intrabony defects. This study was designed to compare the clinical and radiographic effects of EMD treatment to that of open flap debridment (OFD) for two and three walled intrabony defects.Materials and Methods: 18 patients were included in this clinical trial which have 24 two and/ or three intrabony defects. Defects were randomly divided into two groups (test and control). Defects in test group were treated with flap surgery plus EMD and in control group with open flap debridment. At baseline and at 3 and 6 months follow up, clinical and radiographic measurements were performed. Data were analyzed using Greenhouse-Geisser test with p<0.05 as the limit of significance.Results: At 3 and 6 months, mean probing pocket depth reduction was greater in the test group (EMD) (4.33 mm and 4.70 mm) compared to the OFD group (2.54 mm and 3.09 mm). Mean values for clinical attachment gain in the EMD group after 3 and 6 months were 4.29 mm and 4.98 mm, and in OFD group were 2.83 and 2.82 mm respectively. Radiographic bone gain measured by radiovisiography technique was greater in the EMD group compared to the OFD group (4.66 mm in EMD and 1.11 mm in OFD group after 3 months and 5.78 mm in EMD and 1.39 mm in OFD group after 6 months). Conclusion: Based on the results of this study, treatment with flap surgery and EMD compared to open flap debridment, produced more favorable clinical improvements in two and three walled intrabony defects.

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.

Background and Aim: Use of provisional restorations is one of the important phases in the treatment of patients who need fixed prosthesis. Some physical properties are required for these materials. The purpose of this study was the comparison of some physical properties of 4 kinds of resins: Trim, Tempron, Duralay (Aria Dent) and Acropars TRII. Materials and Methods: In this experimental study, transverse-strength (TS), setting time (ST), polymerization shrinkage (PS) and temperature rise (TR) during polymerization were tested. In transverse strength test, 5 samples of each resin were made. TS testing was done with an Instron testing machine. ST testing (5 samples in each group) was done with Gilmore needle. In PS test, 11 cylindric samples were prepared from each resin and the shrinkage was examined with digital micrometer (up to 24 hours). In TR test, after mixing the powder and liquid of resins (8 samples in each group), the temperature rise was recorded with 10 seconds interval (up to 15 minutes). Data were analyzed with one-way ANOVA and Tukey HSD tests with p<0.05 as the limit of significance.Results: In TS test, all samples of Trim were bent and no fracture was observed, while Tempron and Duralay showed no significant difference. Both Tempron and Duralay revealed high significant difference with Acropars TRII (P <0.01). In ST test, the difference between groups was significant (P<0.01). The lowest ST was observed in Acropars TRII (7 min), and the highest in Tempron (9.53 min). In PS test, significant difference was observed between Trim and Acropars TRII (P<0.01). PS was completed after 120 min in Tempron and Trim groups. However, PS continued to increase in other groups. In TR test, the difference between groups was significant (P<0.05). Duralay showed the highest TR and the lowest was seen in Trim. Conclusion: In this study, Trim showed better properties than other studied groups. Acropars TRII had the lowest strength. The highest temperature rise was recorded for Duralay and Tempron, respectively.

Background and Aim: Oral lichen planus is a chronic mucocutaneous disease with various clinical expressions. The histopathologic features are not characteristic and may be seen in other diseases. The aim of this study was to determine the clinical and pathologic features of oral lichen planus in oral pathology department of dental school, Tehran university of medical sciences.Materials and Methods: In this case series study, archive of oral pathology department from 1968 to 2002 was reviewed and cases diagnosed as lichen planus and related lesions selected. The diagnosis of oral lichen planus was confirmed by evaluation of microscopic slides. Clinical informations such as age, sex, site and duration of lesions and differential diagnosis as well as microscopic findings were recorded. Data were analyzed with SPSS software using t student, ANOVA, Chi-square and Post Hoc Tukey tests with p<0.05 as the limit of significance.Results: From a total of 402 cases recorded as lichen planus and related lesions, 251 cases were confirmed for final analysis. The mean age of patients was 42 years (5 to 83 years). 50.4% of cases were men and 49.6% women. The most prevalent clinical type was the ulcerative form and the mean duration of disease was 18.4 months. Buccal mucosa was most frequently involved followed by the tongue and gingiva. A white patch, Wickham’s striae and mucosal erythema were the most prevalent clinical appearance and parakeratosis , orthokeratosis and eosinophilic band the most frequent microscopic features.Conclusion: Based on the results of this study, the correlation of clinical and pathological findings in the proper diagnosis of oral lichen planus is emphasized.

Background and Aim: In recent years, CT scan has become available as an alternative to conventional radiography. To date, the utility of Waters view in detecting midface fractures has been rarely evaluated. The aim of this study was to compare the diagnostic accuracy and reliability of Waters radiography with CT scan in detecting midface fractures.Materials and Methods: In this tests evaluation study, waters view and CT scan were performed for 42 patients with midface fracture admitted to maxillofacial surgery department of Shariati hospital. All images were observed and interpreted by an oral and maxillofacial radiologist and an oral and maxillofacial surgeon. Sensitivity, specificity and reliability for Waters view in detecting midface fractures were assessed by Cohen’s kappa test.Results: Sensitivity and specificity for Waters view in detection of midface fratures by the radiologist were 31.79% and 95.35% and by the surgeon were 29.59% and 93.75% respectively. The highest reliability in CT scan and Waters view (in nasal fractures) by the radiologist was 66.67% and was 58.33% by the surgeon in buttress of zygoma. The highest agreement rate between the radiologist and the surgeon for CT scan was in zygomatic arch (78.95%) and for Waters view was in nasal fracture (62.5%).Conclusion: Based on the results of this study, the specificity of Waters view is sufficient to diagnose fractures of lateral orbital wall, infraorbital rim, orbital floor, zygomatic arch, frontozygomatic suture, lateral wall of maxillary sinus and Lefort II fracture. The specificity is not sufficient to diagnose fractures of medial orbital wall and anterior, posterior and medial wall of maxillary sinus. Detection of these midface fractures needs other conventional radiographies or CT scan.

Background and Aim: Sufficient polymerization is a critical factor to obtain optimum physical properties and clinical efficacy of resin restorations. The aim of this study was to evaluate wear rates of composite resins polymerized by two different systems Light Emitting Diodes (LED) to and Halogen lamps.Materials and Methods: In this laboratory study, 20 specimens of A3 Tetric Ceram composite were placed in brass molds of 2×10×10 mm dimensions and cured for 40 seconds with 1 mm distance from surface. 10 specimens were cured with LED and the other 10 were cured with Halogen unit. A device with the ability to apply force was developed in order to test the wear of composites. After storage in distilled water for 10 days, the specimens were placed in the wear testing machine. A chrome cobalt stylus with 1.12 mm diameter was applied against the specimens surfaces with a load of 2 kg. The weight of each samples before and after 5000, 10000, 20000, 40000, 80000 and 120000 cycles was measured using an electronic balance with precision of 10-4 grams. Data were analyzed using t test and paired t test. P<0.05 was considered as the limit of significance.Results: Mean weight in both groups had statistically significant difference before and after all cycles (P<0.05). In halogen group 5000 and 10000 cycles led to significant difference with 40000, 80000 & 120000 cycles (P<0.05). In LED group 20000 cycles had significant difference with both 5000 and 120000 cycles (P>0.05). Conclusion: Based on the results of this study, LED and halogen light curing units resulted in a similar wear rate in composite resin restorations.

Background and Aim: Dentists are exposed to mercury from dental amalgam in their routine occupational practice. Excess exposure to mercury is harmful and the measurement of mercury content of urine is a reliable and valid assessment of the level of mercury exposure from dental amalgam. The aim of this study was the measurement of urine mercury in dentists of Tehran and assessment of some possible related factors.Materials and Methods: This cross-sectional study was performed randomly on 211 dentists in all regions in Tehran city (center, north, south, west, and east) between 1381 and 1383. Dentists were asked to give a sample of urine in the day of visit and to complete a questionnaire consisting of variables such as age, working history, handling of amalgam, environmental parameters and general health situation. Urine samples were analyzed by cold vapour atomic absorption spectrophotometry. Data were analyzed by Kruskall Walis, Kendall and Mann Whitney tests, with p<0.05 as the limit of significance.Results: The mean of urine mercury content in Tehran dentists was 3.1 (± 3.95) µg/lit which was lower than the international TLV (Threshold Limit Value). There was a significant relation between urine mercury level and working hours per day (P=0.006). This relation was observed with working hours per week too (P=0.006). In general dentists, there was a positive relation between urine mercury and age (0.008) as well as the practicing years (P=0.034). A significant relation was found between urine mercury and the number of amalgam repairs and replacements in restorative specialists (p=0.039). There was a significant relation between the number of amalgam fillings in the mouth and urine mercury in general practitioners (p=0.027). The type of amalgam (predosed capsules or bulk powder) had a significant effect on the urine mercury content (P=0.001). There was no significant relation between urine mercury and other variables of the study such as the squeezing of triturated amalgam, storage method of residual amalgam, method of storing mercury and office ventilation.Conclusion: Based on the results of this study, the mean urine mercury content of dentists of Tehran was below the international TLV. The use of precapsulated amalgams had significant effect on the urine mercury. Most of the dentists were working in public or semiprivate clinics, so it is concluded that the level of general hygiene and specially mercury hygiene in these centers seems to be acceptable.

Background and Aim: Several risk factors directly affect the development of periodontal diseases. Also some systemic diseases act indirectly as predisposing and aggravating factors. Osteoporosis is one of these factors and one of its main causes is lack of physical activity in postmenopause period. The incidence of osteoporosis is increasing in our country. The goal of this study was to evaluate the periodontal condition of women with osteoporosis and osteopenia referred to bone densitometric division of Loghman hospital in 2003 and compare to control group.Materials and Methods: In this case control study based on BMD (Bone Mineral Density) measurement of back and thigh using DEXA method, 60 patients referred to bone densitometric division of Loghman hospital, were randomly selected. Cases were divided into three groups, 20 with osteoporosis, 20 with osteopenia and 20 normal cases. Periodontal indices consisting of plaque index (PI), tooth loss (TL), gingival recession (GR), probing pocket depth (PPD) and papilla bleeding index (PBI) were evaluated by clinical and radiographic examination. Data were analyzed by Kruskall Wallis and Dunn tests with p<0.05 as the limit of significance.Results: PBI, PI and TL were significantly higher in osteoporotic group than osteopenic and normal group. PPD was not different in the three groups. Due to the low prevalence of recession in our study, this parameter was not included in the statistical analysis.Conclusion: It seems that osteoporosis does not increase the incidence of periodontal diseases because it affects bone quality rather than quantity. In osteoporosis calcium deficiency and increasing age lead to decreased physical activity and ultimately affect the patient's oral hygiene performance. Thus, periodontal manifestations are presented as gingival bleeding and gingivitis.

Background and Aim: Iranian temporary cement, Tem Band, has been manufactured by Golchai company, and introduced to market as a suitable material but its properties have not been tested yet. The aim of this study was to investigate the setting time, film thickness, compressive strength, disintegration and arsenic content of Tem Band and Temp bond temporary cements and compare them to ISO 3107.Materials and Methods: In this experimental study, 12 samples from each cement were obtained and setting time, film thickness, compressive strength, solubility and disintegration were tested according to ISO 3107. In addition, arsenic content was tested based on ASTM 6052. Data were analyzed with t-test and p<0.05 was considered as the limit of significance.Results: The average setting time of Tem Band was 5 minutes and 47 seconds (4.17 minutes for Temp Bond), the average film thickness was 6.67 micrometer for Tem Band and 4.08 micrometer for Temp Bond. There was no difference between two cements regarding setting time and film thickness and for both was at the standard range. Compressive strength of Tem Band was 5.67 MPa and 8.5 MPa for Temp Bond. The difference was statistically significant but for both cements was less than standard (35 MPa). There was no significant difference regarding the solubility and disintegration tests. In both samples, the solubility and disintegration values were in standard ranges. Both cements did not contain arsenic but lead level was at the maximum standard range in Tem Band.Conclusion: Considering these results, both cements are applicable to different clinical situations based on their physical properties. Studies on the biocompatibility of the Iranian cement are recommended.

Background and Aim: The improvement of the physical and chemical properties of resins as well as great advances achieved in the field of chemical bonding of resin to metal has changed the trend of restorative treatments. Today the second generation of laboratory resins has an important role in the restoration of teeth. The clinical bond strength should be reliable in order to gain successful results. In this study the shear bond strength (SBS) between targis (a ceromer) and two alloys (noble and base metal) was studied and the effect of thermocycling on the bond investigated. Materials and Methods: In this experimental study, alloys samples were prepared according to the manufacturer. After sandblasting of bonding surfaces with 50µ AI2o3 Targis was bonded to the alloy using Targis I link. All of the samples were placed in 37°C water for a period of 24 hours. Then half of the samples were subjected to 1000 cycles of thermocycling at temperatures of 5°C and 55°C. Planear shear test was used to test the bond strength in the Instron machine with the speed rate of 0.5mm/min. Data were analyzed by SPSS software. Two-way analysis of variance was used to compare the bond strength among the groups. T test was used to compare the alloys. The influence of thermocycling and alloy type on bond strength was studied using Mann Whitney test. P<0.05 was considered as the limit of significance.Result: The studied alloys did not differ significantly, when the samples were not thermocycled (P=0.136) but after thermocycling a significant difference was observed in SBS of resin to different alloys (P=000.1). Thermal stress and alloy type had significant interaction, with regard to shear bond strength (P=0.003). There was a significant difference in SBS before and after thermocycling in noble alloys (P=0.009), but this was not true in base metals (P=0.29). Maximum SBS (19.09 Mpa) belonged to Degubond 4, before thermocycling. Minimum SBS (8.21 Mpa) was seen in Degubond 4 after thermocycling. Conclusion: The effect of thermocycling in reducing bond strength of resin to metal depends on the type of alloy. The noble metal studied is significantly affected by thermal tensions.

Taurodontism is a rare dental anomaly in which the involved tooth has enlarged and elongated body and pulp chamber with apical displacement of the pulpal floor. Endodontic treatment of these teeth is challenging because it requires identifying the number of root canals. A case of bilateral involvement of maxillary first molar teeth is presented. Endodontic treatment of the right maxillary first molar with taurodontism was indicated due to irreversible pulpitis. In this article, we described the procedure of root canal therapy for this case.