Introduction: Long-term clinical evaluation of dental implants and their surrounding structures is of utmost importance to acquire knowledge about reasons for implant success and failure.However, accurate and reproducible results are difficult to obtain. The aim of the present study was to examine bone height around endosseous implants on digital conventional radiographs (DCR) and direct digital subtraction images (DSI) prior to loading.Materials and methods: In this experimental study, bone height around 10 implants in 6 patients was assessed by 2 observers. Standardized digital radiographs were obtained just a week and 3 months postoperatively and subtracted by means of EMAGO software. Then the observers evaluated bone height on DCRs and DSIs. MINITAB software and paired t-test were used for statistical analysis (a=0.05).Results: Comparative evaluation of bone height indicated significantly higher values on DCR than on DSI (p value=0.002). The observers also had statistically significant variability in this assessment (p value=0.00003).Conclusion: DSI demonstrated lower values of linear measurement of bone height around endosseous implants compared with DCR. Interobserver variability should be considered when comparing values from follow-up studies.

Introduction: Accurate estimation of remaining alveolar bone using conventional tomography is essential in implant treatment. The purpose of the present study was to evaluate the accuracy of conventional spiral tomography in determination of alveolar bone height in posterior mandibular region.Materials and Methods: Thirty edentulous regions were selected in the mandible and assessed by conventional tomography. Residual bone height was measured on tomograms. Panoramic radiography was performed on patients after implant placement. The remaining bone height was measured on panoramic images. The magnification coefficient was determined by comparing the real and radiographic implant lengths. The effect of magnification was eliminated and the resultant data were used as the gold standard. Data were analyzed with SPSS 15 using paired t-test and the measurements on tomograms were compared with the gold standard (a=0.05).Results: There was a significant difference between the accuracy of radiographic measurements using the conventional spiral tomography (0.37±0.89) and the gold standard (0.29±0.81) (p value=0.03).Conclusion: Under the limitations of the present study, the accuracy of conventional spiral tomographic images was less than the real dimensions.

Introduction: Some studies conducted so far suggest that exercising during adolescence and young age can increase the amount and density of bone minerals to be stored for the age of senility. However, it has not been confirmed yet what type and intensity of bone minerals may provide for a maximum rate of the anabolic stimulation. Thus, the purpose of this study is to compare the amount and density of the bone minerals in male soccer and handball professional athletes with those of male non-athletes’.Materials and Methods: This is a an experimental research study on 42 males ranging 20-30 years old who were divided into three groups consisting of: 14 professional soccer athletes (Experimental Group 1) ,14 professional handball athletes (Experimental Group 2) and 14 young male non-athletes (Control Group). The athletes had the experience of at least three continuous years of regular professional exercising (3 sessions a week) and participating in national championships. These participants were selected from Mashhad athletic clubs, while the non-athletes were experiencing their first session of exercising in the club. Using DEXA, the participants’ BMD of arm femur and bone mass was measured. Then, the collected data were investigated at the significance level of 5 percent, using descriptive statistics and unilateral variance analysis as well as LSD pursuit test.Results: The obtained results from this research indicate that there was not any significant difference among the three groups of the study in terms of BMD of the arms. Also, in terms of femur and bone mass, there was no significant difference between two groups of athletes, i.e. soccer players and handball players (P=0.465). However, the findings suggest a significant difference between the control group and soccer player group (P=0.001) and also between the control and handball player group (P=0.004).Conclusion: As a result, the findings of this study conform to the theory which states that bone response to the mechanical loading depends on the type and style of athletic activities.

Background: This study aimed to compare the gonial angle and alveolar bone height changes between panoramic and lateral cephalometry radiographic images in class II malocclusion patients before and after orthodontic treatment. Methods: The obtained radiographic images were selected from among 120 class 2 malocclusion cases. The gonial angle and alveolar bone height were measured in the midline and molar regions of panoramic and lateral cephalometric radiographs using the software tools before and after the treatment of patients. Study data were analyzed by SPSS statistical software (version 21. 0), and a significance level was set to 0. 05 for all statistical tests. Results: Based on the results, no significant difference was found regarding the gonial angle before and after treatment on the right and left sides in panoramic radiography and the gonial angle changes before and after treatment in cephalometric radiography (P > 0. 05). However, the obtained results for posterior and anterior alveolar ridge height were significant in panoramic and cephalometric radiographs (P < 0. 05). Moreover, the comparison of the measured gonial angle values before treatment in panoramic and cephalometric radiography represented a significant level (P < 0. 05). Eventually, the statistical results suggested that the alveolar bone height differences between panoramic and cephalometry radiography were significantly different in both anterior and posterior regions after treatment (P < 0. 05). Conclusions: The findings indicated that only measurements obtained from the panoramic radiography were valid for the gonial angle. However, panoramic and cephalometry radiography procedures cannot be replaced for assessing the anterior and posterior alveolar bone height.