مجله دانشکده دندان پزشکی اصفهان
سال یازدهم شماره 6 (پیاپی 53، بهمن و اسفند 1394)

Discoloration of dental composite resins is one of the most common reasons for replacement of these restorations. This in vitro study was carried out to evaluate the effect of aging on discoloration of Silorane-based Filtek P90 and micro-hybrid Z250 composite resins.
This experimental study was carried out on 10 disk-shaped Filtek P90 and Z250 samples, measuring 9 mm in diameter and 2 mm in thickness. The samples were stored in distilled water for 24 hours after they were prepared for completion of the setting process. Initial color measurements were performed with a spectrophotometer. Then the samples underwent 384 hours of aging. Final color change measurements were then carried out and the results were analyzed with independent-samples t-test and repeated-measures ANOVA (α=0.05).
Silorane-based composite resin (Filtek P90) showed higher ΔE (14±1.1) in comparison with Z250 (10±0.06) (p value Under the limitations of the present study, the discoloration of Filtek Z250 was less than that of Filtek P90.

Astragalus honey has valuable therapeutic effects; however, its antibacterial effect is not well understood. In this study the antimicrobial activity of astragalus honey on three species of Lactobacillus strains involved in the process of tooth decay was evaluated.
The present in vitro study wascarried out to determine the effect of different concentrations of astragalus honey on three Lactobacillus species. Different concentrations of honey (9.3, 18.75, 37.5, 75, 150, 300 and 600 ppm) were prepared by adding sterile water to pure honey (1200 ppm). Antibacterial activity of honey was determined by serial dilutions and the disk diffusion method. Data analysis was performed with SPSS 20, using one-way ANOVA and comparison of means with Tukey test (α=0.0001).
Although a honey concentration of 1200 ppm strongly inhibited the growth of all the three Lactobacillus strains, concentrations below 75 ppm were more effective. The minimum inhibitory concentrations (MIC) of honey against L. casei (PTCC 1608), L. rhamnosus (PTCC 1637) and L. plantarum (PTCC 1058) were 75, 100 and 100 ppm, respectively and the minimum bactericidal concentrations (MBC) were 100, 150 and 150 ppm, respectively. Zones of inhibition for 1200 ppm concentration at 24, 48 and 72 hours for L. casei were 10.6, 11.2 and 11.77 mm, respectively, with 10.2, 10.3 and 11.05 mm for L. plantarum and 9.14, 9.90 and 10.2 mm for L. rhamnosus, respectively (p value Based on the results, astragalus honey can be used as a natural antibiotic; however, further studies are necessary to evaluate the antibacterial activity of honey.

The aim of this study was to evaluate the frequency of procedural errors during root canal treatment on periapical radiographs of patients referred for the first time to the Oral Radiology Department of Afzal Dental Clinic in 2014‒2015.
In this cross-sectional study, periapical radiographs of 957 endodontically treated teeth of patients referred to the Oral Radiology Department of Afzal Dental Clinic from 2014 to 2015 were scanned and evaluated by a radiologist and an endodontist. The quality of endodontic treatment was evaluated in 3 steps of access cavity preparation, canal preparation and obturation. Data were analyzed with SPSS 20 using descriptive statistics, tables, figures and Pearson’s test (α=0.05).
Of 957 endodontically treated teeth only 286 (29.88%) were error-free, 194 (67.83%) of which were maxillary and 92 (32.17%) were mandibular teeth; 41.5% were incisors and canines, 31.1% were premolars and 23.5% were molars. Under-extension, inadequate preparation and single cone were the most frequent errors. Pearson’s correlation coefficient showed low correlation between single cone, strip perforation, gaps and under-extension on one hand and jaw type and tooth type on the other hand (p value Errors were found in two-thirds of endodontically treated teeth and only 30% of the samples were error-free.

Root surface preparation refers to removal of the smear layer from the root surface. The aim of this study was to compare the amount of smear layer removal from the root surfaces following root planing alone and the use of CO2 and Er:YAG lasers using scanning electron microscopy
In this experimental in vitro study, 18 root segments from periodontally involved teeth were prepared and distributed into 3 groups (n=6): group A: treated with Er:YAG laser (2.94 micron,120 mj with water and air, 15 seconds, 20 Hz, 7-8 mm from the surface of segment, perpendicular to the root surface); group B: treated whit CO2 laser (10.6 micron, 3 W, 4 seconds, 5 cm from the surface, perpendicular to the surface); group C or control (scaling and root planing with a curette only). The specimens were evaluated under a scanning electron microscope to determine the amount of smear level removed (SLR) and micrographs were taken. Data were analyzed using Mann-Whitney and Kruskal-Wallis tests (α=0.05).
The results showed significant differences in SLR between the three groups, with significantly greater SLR in both Er:YAG (p value = 0.002) and CO2 (p value = 0.026) laser groups compared to the control group. However, there was no significant differences between the two laser groups (p value = 0.937). In the Er:YAG laser group, the smear layer was removed completely, resulting in an irregular surface with partially open tubules. In the CO2 laser group, too, the smear layer was removed completely, resulting in partially open dentinal tubules but the surface in this group was smooth. In the control group, smear layer persisted and some dentinal tubules were opened.
It seems application of both CO2 and Er:YAG laser to root surfaces removes the smear layer and partially opens the dentinal tubules.

Periodontists use some vague criteria to assess success of periodontal treatments. This study used Delphi technique and periodontists’ experience to determine agreement on success criteria of periodontal treatment.
In this descriptive study 15 practicing periodontists from Esfahan were questioned to determine the importance of attachment level, probing depth, mobility, plaque, inflammation and patient satisfaction following periodontal treatment of mandibular anterior teeth in patients with moderate-to-severe chronic periodontitis. The periodontists were asked to answer questions about the relative importance of these factors, the minimum acceptable level for each criterion and the length of time for these parameters to remain stable. The frequency distributions of the answers were determined.
Following two rounds of Delphi surveys, the periodontists considered the attachment level, bone loss, plaque level and esthetics to be very important parameters for successful periodontal treatment. Probing depth, inflammation, function and patient satisfaction were considered to be important factors for successful periodontal treatment.
The results of this study showed that attachment level, bone loss, plaque level and esthetics have the highest level of importance in successful periodontal treatment.

Knowledge of the exact location of the floor of maxillary sinus is a very important factor in relation to safe regions for implant therapy and surgery. The aim of this study was to evaluate the distance between the alveolar crest and maxillary sinus floor on cross-sectional, 3D and panoramic views of CBCT.
A total of 94 CBCT images taken with Galileos machine were selected for the purpose of this cross-sectional study, using convenience sampling. The distance between the alveolar crest and the floor of maxillary sinus was determined on 3D, panoramic and cross-sectional views at the regions of teeth #4, #5, #6 and #7 by two radiologists. Data were analyzed with SPSS 20, using the repeated-measures ANOVA, paired t-test and kappa ratio (α=0.05).
There were significant differences in the distances between the alveolar crest and the floor of the sinus in the second premolar area on the three different views (p value = 0.011). However, there were no significant differences in other areas between the three views (p valuefirst premolar = 0.602, p valuefirst molar = 0.079, p valuesecond premolar = 0.498). T-test revealed significant differences between 3D and cross-sectional views (p value = 0.008) and 3D with panoramic views (p value = 0.001), but the difference between the panoramic and cross-sectional views was not significant (p value = 0.868).
In comparisons made in relation to the distance between the alveolar crest and the floor of the maxillary sinus, there were significant differences between 3D and cross-sectional, and 3D and panoramic views; however, the difference between cross-sectional and panoramic views was not significant.

Unfortunately, despite various advantages of CBCT technique, prescription of CBCT by dentists in Isfahan is low, which might be attributed to low awareness about CBCT or its indications. The aim of this study was to evaluate awareness of dentists in Isfahan about CBCT in 2015.
In this cross sectional study 240 dentists in Isfahan taking part in a re-training course were selected with simple random sampling technique. A questionnaire consisting of 14 questions on awareness and 7 questions on CBCT, its advantages and disadvantages, a history of its prescription and reasons for prescribing and not describing it was distributed among them. Data were analyzed using descriptive statistics, tables and figures.
Of 240 dentists taking part in this study, 145 were male (60.4%) and 95 were female (39.6%); 79.7% of the subjects had not received sufficient education about CBCT and only 20.3% had received education in this respect. Furthermore, 2.6% of the subjects did not know CBCT was available in Isfahan. On the whole, the majority of the subjects achieved moderate to good awareness scores.
Based on the results of this study, awareness of dentists in Isfahan about CBCT was moderate to good.

The most common morphology of mandibular molars is two roots and three root canals; nonetheless, unusual anatomic variations may exist.
Case reports: This study reports two cases of mandibular first molars with a mid-mesial root canal that underwent treatment and follow-up in the Endodontics Department of Isfahan School of Dentistry. During the initial treatment, the mid-mesial root canal had not been detected in both cases due to the failure to prepare a convenient access cavity.
Preparation of convenient access cavity, knowledge of canal anatomy and presence of uncommon variations should be more appropriately taken into account during the general training and systematic re-training programs of general dental practitioners.

Implant-supported overdentures have attained a special place as a successful alternative to conventional complete dentures. One of the most necessary repair procedures is relining to improve overdenture fit with underlying mucosa, particularly in the first year after delivery. The purpose of this study is to review various methods of relining in two types of implant-supported overdentures (ball and bar attachments).
Search strategy: All the relevant articles indexed in Pubmed from 1994 to 2012 were searched for the purpose of this review, using the following key words: reline, rebase and implant-supported overdentures. In ball attachment-supported overdentures we can use “abutment level” reline method with or without removal of the old cap during impression taking and then put the new caps directly (chair side) or indirectly in place. Of course, in the direct method we should overcome problems like holding the retentive caps in a specific direction and preventing penetration of acrylic resin into the undercuts. Another method for relining these overdentures is to use open impression coping and perform fixture level impression taking. Most of the relining methods of bar attachment-supported overdentures are based on direct or indirect clip attachment to denture base (taking an impression of the residual ridge and bar and use of open impression coping and a long waxing screw). In most of the relining methods which have been suggested for bar attachment-supported overdentures, it is not possible to accurately register the anatomic form of soft tissues under the bar attachment.
Clinical stages of relining in ball attachment-supported overdentures are probably simpler and less common than bar attachment overdentures. In these methods it is necessary to check occlusal contacts and correct them if necessary, like all the relining methods of complete denture and then remove a thin layer of denture inner surface, denture borders and undercuts.

Radiographs are essential tools for detection of caries. Panoramic, periapical and bite-wing radiographs are used alone or in various combinations to detect caries. With the introduction of digital radiography, it has been used extensively in panoramic radiography. The aim of this study was to evaluate the accuracy of digital panoramic and bite-wing radiography in the detection of proximal caries.
In this analytical study, panoramic and bite-wing radiographs of 50 patients were evaluated. The radiographs were evaluated for proximal enamel and outer third dentinal caries in molar areas by two observers. Intra- and inter-observer agreement was analyzed with Cronbach's Alpha and diagnostic accuracy was evaluated using receiver operating characteristic analysis (ROC) at a significance level of α = 0.05.
Intra- and inter-observer agreement levels were high. The mean values of area under curve (AUC) were 0.978 and 0.952 for panoramic and bite-wing radiography, respectively. There were no significant differences between AUCs of these two imaging modalities (p value = 0.001).
The accuracy of panoramic radiography in evaluation of proximal caries in molar areas was comparable to that of bite-wing radiography.