Journal of Dental Medicine

Generally speaking, when preserving and restoring the gnathostomatic system the dentist controls tooth morphology to insure proper distribution of stress. So, we restore a portion of a tooth or all the teeth in such a manner as to subject the associated parts of the system to the least stress. We evaluate our diagnosis and control it in our treatment. The treatment should be based on the scientific method. We create optimal occlusion or a desirable functional state of the masticatory system.  Many persons with occlusal imperfections will not have symptoms of functional disorders. This is the psychological adaptive capacity of the neuromuscular system, teeth, dental arches, and periodontal tissues.Recent developments in dental material, technology and instruments however, have simplified the taskaf restoring rebuilding and rehabilitating diseased mouths. So, optimum oral health and function should be the prime objective of all treatment procedures. Because the ultimate aim will always be to restore the mouth to health and preserve this status throughout the life of a patient.

Normal 0 false false false EN-US X-NONE AR-SA Correct contour and shape of crown margin or casting finishing line is not sufficient for healthy status of tissues and teeth filling materials.  Thus, all the requirements for preservation of tissues should be provided. Gingival health is a very important issue that should be considered before prosthetic treatments. Via conventional methods, supra gingival margins are the first choice of treatment specially when placed on anatomical crown. If there are specific indications such as esthetics, age, caries risk, free gingival margin sensitivity or subgingival fillings , the place of crown margin could be modified.

Normal 0 false false false EN-US X-NONE AR-SA The accuracy of relined impressions is usually acceptable and in some cases is even more accurate than principal impression. Relined Polysulfide and condensational silicone impressions are more accurate than polyether impressions. The reline method compared to retaking them is more economic and needs less chair time.

Normal 0 false false false EN-US X-NONE AR-SA Present study is conducted to evaluate antifungal activity of the denture cleansing solutions made in Iran. 40 patients who were diagnosed as chronic atrophic candidiasis after laboratory tests confirmation, were selected .Before and after using denture cleansing solution, their maxillary denture were sampled by a swab. The samples were cultivated and the resulting colonies were counted and the exact number of the colonies in 1cc of each suspension was determined. It was found that after using the solution, cultivation results were negative. Therefore, this solution has the potential to eradicate all the fungi causing chronic atrophic candidiasis.

  Since 3 decades ago, dental equipments and technologies as well as materials have been greatly improved and numerous effective treatment modalities have been discovered. As a result, the number of survived teeth have been greatly increased and many studies have been conducted in this regard. Fluride therapy is found as an effective treatment modality and can reduce dental caries up to 60%, due to recent evidences.

This investigation was performed according to the widespread application of base metal alloys and few articles published about the marginal integrity of restorations fabricated by these metals.Three standard dies of a maxillary first premolar were prepared with a flat shoulder finish line in buccal aspect and chamfer in palatal. One of them left with no change. On the buccal aspect of the second and third dies 135?and 1607 bevel were added respectively Using dual wax technique, nine wax patterns were formed on each die and casting procedure of selected non precious alloy was performed by centrifugal method. Marginal gaps of each copping seated on dies were measured by scanning electron microscope (SEM) with X500 magnification. Measurements were done on three areas of marked dies on buccal aspect. Measurement son palatal aspect was done on marked midpalatal point as control.Results and statistical analysis showed no significant difference among marginal gaps in lingual aspect.But on the buccal aspect there were statistically significant differences among the groups (P<0.001). Flat shoulder had the best marginal integrity (mean 4 micron). Shoulder with 160' bevel had the most marginal gap (mean 26.5 micron) and shoulder with 1357 bevel was between two other groups (mean 15.7 micron).

Background and Aim: The use of fiber reinforced posts in endodontically treated teeth has become increasingly common. But their retention in root canals must be considered seriously. The aim of this study was to evaluate the effect of light-cure and dual-cure bondings on regional bond strength of a fiber composite post.

Materials and Methods: In this experimental in vitro study, 20 endodontically treated teeth were randomly divided into two groups. In the first group, a dual-cure bonding (Scotchbond Multi-Purpose Plus, 3M ESPE/USA) [SBMP] was used and in the other group, a light-cure bonding (Single Bond, 3M ESPE/USA) [SB] was applied according to the manufacturer's instructions. A dual-cure resin cement (Rely X ARC, 3M ESPE/USA) was used to cement the post (Glassix, Harald Nordin SA,Switzerland). Coronal 8mm of cemented posts were sectioned in equal thirds using a 0.1mm diamond disc. Each slice was polished by a soft and wet abrasive paper in order to get a 2mm thickness. Loading was performed by a testing machine (Zwick/Germany) at a speed of 1mm/min until the post was dislodged. Data were analyzed using one-sample Kolmogorov-Smirnov, T and ANOVA tests with P<0.05 as the level of significance.

Results: There was a significant difference between the two adhesive systems in the middle third of the canal block with higher bond strength in SBMP group (p=0.02). In SB group the bond strength of the cervical region was higher than the middle and apical thirds (p<0.05). In SBMP group, there was no statistically difference between bond strength of the three regions (p=0.117).

Conclusion: Based on the results of this study, dual-cure bonding could be recommended for composite post cementation into root canals, because its bond strength was more uniform in different regions of root and greater in the middle and third regions.

Background and Aim: Polymerization shrinkage of resin cements during setting leads to stress on teeth receiving indirect esthetic restorations. Some methods like blocking out undercuts during cavity preparation with glass Ionomer can reduce the mass of resin cement and therefore the amount of stress. The aim of this study was to evaluate the fracture resistance of molar teeth, receiving class I ceramic inlays with two different methods of blocking out undercut.

Materials and Methods: In this experimental study, thirty intact molar teeth were randomly divided into three groups of 10 each. One group was maintained intact as the control group. Similar class I cavities with identical undercuts were prepared on the other groups. In group 2 the undercut was filled with light cured glass Ionomer (vitremer 3M) before making impression, and in group 3 they were blocked out in the lab before preparation of the inlay. All the teeth in test groups were restored with indirect ceramic inlays.(vitadur - Alpha/ single bond / Rely X ARC). After thermocycling load causing fracture was assessed by universal testing machine. All the specimens were examined under a steriomicroscope (X40) to determine type of fracture. The results were analyzed by one way ANOVA and Tukey HSD tests. P< 0.05 was considered as the level of significance.

Results: The restored groups showed significantly less fracture resistance than the control group. The difference between two test groups was not significant. The fracture in group2 had less destruction.

Conclusion: According to the findings of this study, blocking out the undercut with two different methods (using glass ionomer/ or blocking it out on the die) made no diferrence in fracture resistance.

Background and Aims: Since there is a relationship between the tooth size and race, it seems that having statistical information about the tooth size in a society in which the orthodontic treatments are done, is very important. The aim of this study was to determine the relationship between the mesiodistal width of permanent incisors and first molars in both jaws with unerrupted permanent canine and premolars. New regression equations for prediction of the sum of mesiodistal width of canine and premolars were established.

Materials and Methods: A total of 715 dental casts (526 female, 189 male) were recruited from the department of orthodontics of Shiraz dental school and private offices of orthodontists for this cross sectional study. The greatest mesiodistal widths of all teeth were measured with digital caliper with accuracy of 0.01 mm. All data were analyzed with SPSS software and Pearson Correlation, independent T-test, paired sample T-test and multiple linear regression tests.

Results: Tanaka-Johnston equations and Moyer’s prediction tables had significant difference with mesiodistal dental width of south Iranian population, so new regression equations (based on incisors and first molars) for different jaws and sexes were presented in this study for south Iranian population. The best suggested regression is the regression that is based on all maxillary and mandibular incisors and first molars and has 12 variables. The suggested regression for prediction of maxillary canine and premolars based on the summation of mesiodistal width of all incisors and first molars in both jaws was Y=0.177X+4.227 and for prediction of mandibular canine and premolars was Y=0.188X+2.730, which a the greatest in r2 prediction of unerrupted teeth in comparison with the regressions based on incisors alone or incisors and first molars in one jaw.

Conclusion: Tanaka-Johnston and Moyer’s prediction tables are overestimated the actual size of south Iranian’s teeth width. So new regression equations based on incisors alone and incisors and first molars are suggested to increase the accuracy of space analysis in both jaws.

  Background and Aims : Dentists have usually a critical role in diagnosing oral cancer lesions in their early stages. In this study we aimed to assess the senior dental student’ and dentists’ knowledge, attitude and behaviors regarding oral cancer in Isfahan.

  Materials and Methods: A valid and reliable self-administered questionnaire was designed to assess the current practice, knowledge and attitude of general dentists working in Isfahan-Iran and senior dental students regarding oral cancer lesions. The questionnaire was consisted of questions to assess the knowledge and attitude regarding diagnosis, risk factors and prognosis of oropharyngeal cancerous lesions. The frequencies of answers to questions in sections of practice and attitude (just for dentists) and sum score of questions in knowledge section were calculated and compared using statistical analysis regarding age, sex, duration of experience and practice setting ) p ublic/private) of participants. Data were analyzed using ANOVA, chi-square, linear regression and logistic regression.

  Results: 139 questionnaires from dentists and 57 questionnaires from students were returned. The mean score of dentists’ knowledge was 5.41 out of 13 (CI95%=5.03-7.79 ). Significant differences were observed among dentists regarding their experience (P=0.001). Only one fifth of the dentists in our survey reported to perform oral cancer examination for all of their patients in age of 40 and above and just about 34% of dentists gained acceptable level of knowledge. Among senior dental students, the status of knowledge was better as about 58% of them gained the level of acceptance (P=0.01).

  Conclusion: Although dentists were willing to follow the diagnostic protocol for oral cancer, they were mostly unsatisfied with the level of their knowledge. Therefore, this study highlights the need for educational planning and training activities in general dentists with regard to the risk factors and early detection of oral cancers.