Dental Research Journal
Volume:1 Issue: 1, Jan 2003

Introduction
This study detennined and compared the caries prevalence and plaque index in 12-year-old girl students living in Isfahan and Kashan, two cities of Iran. In addition, correlation between plaque index (PI) and DMFf index was investigated.
Methods and Materials
One hundred and ninety five 12-year-old junior high school girl students were selected in each city by multistage sampling method. Caries prevalence was determined according t WHO criteria method. Plaque index was also recorded. The results were statistically analyzed with
Student''s -t-test and Pearson''s correla- tion coefficient test.
Results
Means :f:SD of DMFf, DT, MT, FT Indices and PI were 4.44±2.38, 3.68±2.4, 0.031±0.173, 0.718±l.391 and 0.757±0.137 in Isfahan and 3,88±2.40, 3.71±2.38. 0.15±0.123, 0.154±0.663 and 0. 805±0.129 in Kashan respectively. The DMFf and Ff indices in Isfahan were significantly higher (pO.O5). A signif-icant correlation was found between DMFf index and PI and also between DT index and PI (p

The purpose of this investigation was to determine and compare the frictional resistanc produced by stainless steel brackets with 0.018 inch slot of Dentaurum, Ortho Organizers and Unitek companies, used in combination with 0.016 inch stainless steel wires from Dentaurum, Ortho Organizers and Unitek companie during stimulated canine retraction in vitro. A testing apparatus was made to simulate the clinical situation of canine retraction through tipping- uprighting movements. The measurements were made using an Instron Universal Testing Machine and the tests were proceeded under dry con- dition. Statistical analysis showed significant difference of frictional force among different wire compa- nies (PO.O5).

Introduction
Reducer decrease the den- sity of dark radiographs. Copper Sulfate Reducer (CSR) is one of the superpropor- tional reducers. Reduction is superpropor- tional, that is, the percentage of reduction is greater in darker area than it is in lighter area. Resolution is increased on reduced radiographs. For root canal length measurement we need maximum diagnostic quality. The purpose of this study was to determine usefulness of CSR for improving the diagnostic quality of overdeveloped dark working radiographs that were taken during root canal length measurement.
Method and materials
Series of 116 radiographs were prepared using double film pockets. One filrom each pocket was processed manually. It was saved as control. The other was put in concentrated developer to get dark. The dark film was immersed and reduced (bleached) in CSR until it gets light. It is then rinsed, redeveloped in artificial light in weak developer, rinsed again, and fixed. The reduced film was used as sample. The diagnostic quality of these two films were compared by giving scores from 1 tq 5 to their diagnostic quality.
Result
There was statistically significant difference between diagnostic quality of control and sample films.
Conclusion
Diagnostic quality of overdeveloped radiographs was increased , after reduction by CSR

Determination of the least length of gutta-percha that is necessary for apical seal after post space preparation. Introduction: After root canal therapy, restorative treatment is necessary.
Therefore pinhole or post space prepara- tion is made by removing the coronal parts of gutta-percha. The aim of this study was to determine the least length of gutta-percha that is necessary for apical seal after post space preparation.
Meterials and methods
Total of 87 single extracted teeth with no abnormal condi- tion were studied. The samples were pre- pared and their canals were obturated and sealed. AH26 sealer was used. Experimental groups were divided into three groups of 3, 5 and 7 millimeters of remaining gutta-percha. Post space was repared one week later. The whole length of the roots except for the three millimeters of apical was sealed with cyanoacrylate glue and nail polish. The samples were placed in penicillin vial that contained sterilized cultural media (TSB). Human saliva was injected twice a day.
Data collection was made by inspection and registration of turbidity in cultural media daily. Dataobtained from this study was subjected to one-way Anova test.
Results
There was no significant difference between the experimental groups.
Conclusion
3 millimeters of remaining guttapercha with AH26 sealer is the least length that is necessary for apical seal after post space preparation.

The aim of this study was to design and produce a novel coating material in order to obtain two goals including; improvement of the corrosion behavior of metallic dental endodontic implant and the bone osteointegration simultaneously.
Method and materials
Stainless steel 316L (SS) was used as a metallic substrate and a novel Hydroxyapatite / Titanium (HA/Ti) composite coating was prepared on it. XRD and SEM techniques
were utilized to investigate the coating characterization. Electrochemical tests were performed in physiological solutions in order to determine the corrosion behavior of the coated and uncoated specimens. Two types of endodontic implants including; SS with and without (HA/Ti) composite coating were prepared and subsequently implanted in the mandibular canine of 20 cats
after completion of root canal treatment and osseous preparation. After a healing period of 4 months, osteointegration evaluation and histopathological interpretation was carried out using SEM and optical microscopy.
Results
The novel HA/Ti composite oating improves the corrosion resistance and biocompatibility of SS endodontic dental implant. The clinical evaluation and histopathological interpretation results showed that the average bone osteointegration of coated implants were more than uncoated implants. The histopathological results and bone tissue response to the coated implants was acceptable.
Conclusion
It was concluded that HAtfi composite coated SS could be used as well as an endodontic dental implant.

Aim
The aim of this study was to evaluate the effect of the condition of the dental restoration and clinical operation parameters on the amalgam corrosion behavior.
Method and Material
Commercial amalgam namely Oralloy was selected.
The amalgam samples were prepared. After triturating and condensation, the samples were divided into three groups and each group was finished by using one of three clinical procedures: carving, carving-burnishing, carving-burnishing-polishing. A special cylindrical mold was used for the simulation ofthe interproximal areas and proximal
surfaces of the dental restorations. Stainless steel matrix band was laid on the internal mold surfaces and amalgam paste was compacted in the mold. Electrochemical tests were performed at a temperature of 37(1(C in physiological solution in order to determine the corrosion behavior of dental amalgam samples.
Results
The results showed statistically significant differences between the mean corrosion current density values of the comparison three different groups of dental amalgam. Thecarved group shows more corrosion resistance in comparison with the sample near the matrix band as an index of the proximal surfaces of the dental restorations.
Conclusio
Even a simple clinical operation could effect on dental amalgam corrosion resistance. The proximal surfaces of the class II restorations are not only susceptible to concentration cell corrosion but also possess less corrosion resistance.

Introduction
Compomers from the standpoint of surface and mechanical properties are categorized between composite resins and glass ionomer cements. Compoglass is atrade name for such compomers The purpose of this study was to evaluate microleakage of compoglass through enamel and dentinal margins following the use of two different surface conditionings.
Materials and Methods
Forty intact human premolars were chosen and randomly assigned to 4 groups each including 10 teeth. Class v cavities were prepared in the buccal surfaces of the teeth and restored with compo glass as follows: roup I: cavities restored as manufacturer''s instruction. Group 2: the cavities restored such as group 1 and then stored in distilled water for one week. Group 3: the cavity surfaces were conditioned by phosphoric acid prior to priming and restoration. Group 4: the cavities restored such as group 3 and then were placed in distilled water for one week.
Results
The results of this study showed that the minimum degrees of leakage in enamel margins were in group 2 and 4 and in dentinal margins in group 2. The maximum degree in enamel marginswas in group I and in dentinal margins in group 3. Statistical analysis of data showed that there was meaningful difference between groups 2 and 3 in dentinal margins. This difference also was seen between groups I, 3-1, 4 and 2, 4 in enamel margins.
Conclusion
According to the results ofthis study conditioning and water storage decreased the microleakage in enamel and in dentinal margins, conditioning of the margins increased the microleakage.

Introduction
The occlusal vertical dimension changes influence activity and tonocity of orofacial and masticatory muscles. Thus, the function and esthetic of the edentulous patients are affected by these changes. In this study, the effects of changes in vertical dimension on electromyographic activities of masticatory muscles were evaluated.
Methods & Materials
Complete dentures were constructed for 10 edentulous patients. The mandibular dentures were duplicated to change the vertical dimension. Electromyographic activities of right masseter and temporal muscles were recorded in three vertical dimensions: (1) V DO, (2) VDOiâ, and (3) VDO-4mm. The selected functions were maximum voluntary clenching, chewing, swallowing and phonetics. One way ANOVA was used for data analysis
Results
Mean integrated electromyographic activity was more in proper occlusal vertical dimension in different functions. There was no significant difference between the three groups.
Discussion
The results showed that the immediate and few changes of vertical dimension is ineffective in electromyographic activities of masticatory mucsles.