مجله دانشکده دندان پزشکی اصفهان
سال دهم شماره 6 (پیاپی 47، بهمن 1393)

Correction of deep overbite and achieving a long-term stability are still major concerns for many orthodontists. There are three main ways for solving this problem: Bypass arch technique introduced by Ricketts, Segmented arch technique introduced by Burstone and using TADs. The aim of this study was to evaluate and compare the effects of Ricketts and Burstone techniques during correction of deep overbites.

In this clinical trial, 18 female patients with Cl I and II occlusion and more than 4 mm of overbite were selected. The subjects were divided into two groups (n=9). The deep overbite in group A was treated with Ricketts technique and Burstone technique was used for correction of overbite in group B. Fifteen jaws were included in each group. Lateral cephalograms before and after intrusion were used to evaluate the results. Data were statistically analyzed with Student’s t-test and SPSS 18 (α=0.05).

There was a statistically significant difference in the means of true intrusion and extrusion between groups A and B (p value = 0.014 and p value = 0.47, respectively). However, overbite reduction was not significantly different between the two groups (p value = 0.704). In addition, the differences in mean false intrusion (p value = 0.02), changes in the axial inclination of posterior teeth (p value = 0.047) and the angle between axial inclination of upper and lower anterior teeth (p value = 0.002) were statistically significant between the two groups.

Under the limitation of the present study, the results confirmed the superiority of Burstone technique in intruding incisors with less undesirable lateral movements.

Temperature seems to be an effective factor in dentin-composite bond strength. The purpose of this study was to evaluate the effect of rinsing water temperature and water storage duration on the shear bond strength of dentin‒composite resins with etch-and-rinse and self-etching bonding systems. In this experimental study etch-and-rinse systems All-Bond3، OptiBond Fl، Prime & Bond NT and Adper Single Bond and self-etching systems All Bond SE، Clearfil SE Bond، OptiBond All-In-One and FuturaBond were used. The enamel of buccal and lingual surfaces of 192 mounted healthy third molars was removed. The specimens were divided randomly into 16 groups; before using the primer and bonding the composite resin cylinders and dentin surfaces were rinsed with distilled water at various temperatures such as 2 ± 5، 2 ± 22 و 2 ±23±2 and or 50 ±2°C. Composite cylinders were bonded and the specimens were stored in distilled water at 37°C. Shear bond strength was tested after 24 hours and 6 months. Data were analyzed with SPSS 19 using independent-samples t-test. The mean bond strength decreased in all the groups except for All Bond SE and OptiBond All-In-One groups; the decrease was significant for FL (p value < 0. 001) and P&B (p value = 0. 015). By increasing water temperature in all groups except (CSE and ASE) shear bond strength was increased that was significant for Prime & Bond NT (p value = 0. 015) and OptiBond FL (p value = 0. 001). Based on the results، the shear bond strength decreased with all the adhesives with an increase in rinsing water temperature except for two-step self-etch systems and decreased with time in all the groups except for one-step self-etching systems.

Relining is a common technique for maintenance and improvement of denture base fit with underlying mucosa. Some dimensional changes might occur in denture base due to relining procedures. The aim of the present study was to evaluate dimensional changes of denture bases after relining with two direct and indirect methods. An acrylic model of maxillary edentulous arch was selected in this in vitro study. Four reference points were placed on canines (A and B) and second molars (C and D). A 1.5-mm wax layer was placed on the model to make room for relining material. An impression was then made of the model. This impression was poured and 20 casts were poured. A 2-mm wax layer was placed on all the casts and the acrylic were stored in water for two weeks. Relining procedures were carried out directly with GC-Reline material and indirectly with Acrosoft TC material in two separate groups. The created lines were exactly measured by digital caliper three times on each base and the original model and their means were computed. Independent t-test was used for statistical analysis (α=0.05). The maximum discrepancy between the two techniques was observed at AC distance. The minimum discrepancy with the direct and indirect techniques was observed in the BD and AB distances, respectively. The differences between the two techniques and the main model were not significant (p value > 0.05) except for the CD distance in the indirect technique (p value = 0.006). Under the limitations of the present study, the dimensional changes in denture base in both direct and indirect reline were acceptable. Selecting one of these methods would depend on patient’s condition, dentist’s preference and some other factors.

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. 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 (α=0.05). 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). Under the limitations of the present study, the accuracy of conventional spiral tomographic images was less than the real dimensions.

Less bone loss and preservation of more osseous structures have been reported around immediately placed implants. Considering controversies over the success rates of immediate versus delayed implant placement, this study aimed to compare crestal bone loss and success rates of these two implant techniques. In this preliminary clinical trial, 12 implants (6 immediate and 6 delayed) were placed in male patients aged 30‒60. Parallel periapical radiographs were obtained one week later. The patients were re-examined at 6-month and one-year follow-up intervals and PA radiographs were obtained again under the same conditions. Scanned radiographs were subtracted and compared using Photoshop software. Data were analyzed with Mann-Whitney test using SPSS 21 (α=0.05). Immediate implants exhibited less crestal bone loss compared to delayed implants at 6-month (p value = 0.009) and one-year (p value = 0.002) follow-up intervals. The results showed less crestal bone loss around immediately placed implants; therefore, this technique might be considered as a more successful treatment plan for patients compared to the conventional technique.

Helicobacter pylori (H. pylori) is a gram-negative motile spiral-shaped bacterium that is strongly associated with gastroduodenal diseases. Recently, dental plaque has been implicated as a possible source of H. pylori infection. Two important virulence factors that are expressed by the alleles of vac A (vacuolating toxin) and cag A (cytotoxin-associated gene A) have been identified. The aim of this study was to determine whether or not virulence factor genes vac A and cag A are present in H. pylori retrieved from dental plaque in patients with gastritis. In this cross-sectional study, dental plaque specimens from 42 patients with gastritis, referring to the endoscopy section of a hospital, were subjected to polymerase chain reaction (PCR) assay to detect the presence of cag A and vac A genotypes of H. pylori. DNA from H. pylori was detected in 4 dental plaque samples. All these 4 samples were vac A-positive and 2 samples were positive for both vac A and cag A genotypes. The pathogenic strains isolated from the dental plaque in the present study suggest it is possible for more than one virulence factor of H. pylori to exist in some patients. However, further studies are required to confirm this finding.

The manner in which a dentist manages medical emergencies in dental offices depends on the dentist''s knowledge and the instruments and drugs available when emergencies arise. The aim of this study was to assess knowledge, practice, instruments and drugs available and used during medical emergencies in Yazd dental offices in 2014. In this cross-sectional study, 100 general dentists were selected in Yazd by simple random sampling. The dentists filled out a researcher-designed questionnaire. Data were analyzed by independent t-test, Pearson’s correlation coefficient and ANOVA using SPSS 21 (α=0.05). Maximum and minimum job experiences ranged from 1 to 34 years. Mean knowledge score was 77±16; mean performance score was 70±21; mean number of drugs used was 5±2; and the mean of emergency equipment was 2±1. The mean scores of knowledge and performance of female subjects were significantly higher than those of males (p value < 0.001). There was a significant and positive correlation between the knowledge and performance of dentists in medical emergencies (p value = 0.001, r = 0.52). There was a significant but inverse relationship between age and knowledge score (p<0.001, r = -0.43), age and performance score (p value = 0.001, r = -0.60), and work experience and knowledge score (p value = 0.001, r = -0.59). However, there was no correlation between knowledge and the number of drugs used (p value < 0.06, r = -0.56), knowledge and the number of equipment pieces (p value = 0.16, r = 0.13), performance score and the number of drugs used (p value = 0.26, r = 0.01), and the performance score and the number of equipment pieces used (p value = 0.26, r = 0.01). Dentists in Yazd had proper knowledge and performance in medical emergencies; however, it is necessary to update and develop awareness about emergency situations, especially in senior dentists who have graduated many years ago.

Systemic changes and changes in the salivary composition of patients with migraine headaches have already been reported. This study was carried out to evaluate the prevalence of dental caries in two groups of patients with and without migraine headaches.

In this analytical/cross-sectional study 120 patients aged 15‒65, including 60 migraine patients with at least 5 migraine attacks and 60 normal patients, were selected using convenience sampling technique. DMFT (Decayed, Missing, Filled Teeth) and OHI-S (Oral Hygiene Index-Simplified) indexes were used to evaluate oral hygiene status. Data were analyzed with SPSS 20 using multi-linear regression, Mann-Whitney test and t-test (α=0.05).

The means of DMFT in subjects with and without migraine were 13.95±5.05 and 4.08±2.53, respectively (p value = 0.001). Mean of OHI-S index in subjects with and without migraine headaches were 0.12±0.19 and 0.10±0.16, respectively (p value = 0.79). Multi-linear regression showed that migraine had a significant effect on the DMFT and OHI-S indexes (p value < 0.001) after correcting for variables such as age, gender, educational status and income. The results also showed that the effect of age on DMFT and OHI-S was significant (p value < 0.001).

Under the limitations of this study, dental caries was more prevalent in migraine patients than normal individuals; however, the OHI-S was similar in the two groups.

Fluoride is one of the most important materials in preventive dentistry. Although the prevalence of dental caries is inversely related to the concentration of fluoride in drinking water, there is a dose-dependent relationship between fluoride concentration in drinking water and the prevalence of dental fluorosis. Some studies have reported a possible association between fluoride and increased risk of bone fractures, decreased thyroid function, arthritis-like conditions, precocious puberty and osteosarcoma. The purpose of this review study was to evaluate the current status of systemic fluoride in dentistry by considering its advantages and potential side effects.Description: A search was run in PubMed, OVID Evidence-based Reviews, SCOPUS and Google Scholar from 1985 to May 2013 and available reference textbooks. Of all the papers, review articles and valid research papers on the systemic use of fluoride and its advantages and potential disadvantages were selected.

It appears although the benefits of fluoride in combating dental caries are evident, the potential side effects of incorrect use of fluoride, especially its systemic use, should be taken into account. Incorporation of fluoride into drinking water might lead to complications. With recent advances in new methods for controlling dental caries it is advisable to more carefully evaluate the systemic use of fluoride.

Due to the lack of a clear and consistent protocol for periodontal therapy in patients with Papillon-Lefèvre syndrome, periodontal treatment is still a challenge for dentists in such patients. The aim of this study was to investigate the causes of success and failure in periodontal treatment of patients with Papillon-Lefèvre syndrome reported in the literature based on the treatment protocols offered. In addition, this article describes the periodontal treatment of a child with this syndrome during a 6-year follow-up.Case report: A 6-year-old boy, with clinical symptoms of hyperkeratosis of the palms, soles and knees and generalized aggressive periodontitis in primary dentition, was referred to Isfahan Faculty of Dentistry. The disease was confirmed by clinical and radiological evaluations. The patient was treated with a combination of non-surgical and anti-microbial therapy and placed on a monthly recall. Despite severe bone resorption and inflammatory symptoms on follow-up visits, during the last visit the patient exhibited radiographic signs of bone formation, which can enhance the idea that it might be possible to control the patient’s periodontal disease with continuous follow-ups.