Journal of Dental Medicine

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During the human gestation period, various systemic alterations occur in the mother secondary to endocrine changes. These changes, combined with the presence of the gravid uterus, result in conditions affecting the various systems of the mother which must be considered by the dentist.Fetal development is divided into three stages:1) The fertilization and implantation period 2) The embryonic period and 3) The fetal period.The second period characterized by organogenesis which taratogens may result in functional and morphogenic malformations.The ideal dental treatment schedule for the pregnant patient is twice during first trimester, at least once during second trimester and once during third trimester.The second trimester is an ideal time for performing dental treatment.Emergency problem should be alleviated immediately during pregnancy.Indicated medications should not be with held because of pregnancy but patients must be informed of benefits and risks.With careful attention to the special needs of the pregnant patient, the dentist can provide high quality dental care while minimizing potential risks to mother and fetus.Emphasis should be on preventive strategies and meticulous oral hygiene to manage common oral problems associated with pregnancy.

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It has been shown that noble alloys require metal collar to resist distortion when subjected to repeat firing cycle of porcelain. Metal collar is undesirable due to esthetic concerns. Since base metal alloys have superior physical properties, it seems that metal collar would not be necessary for obtaining better marginal adaptation of base metal crowns. The Purpose of this study was to evaluate the effect of metal collar on marginal distortion of base metal- ceramic crowns, Twenty base metal copings were constructed and divided into two groups with and without collars. After surface preparation, porcelain was applied onto the surface of specimens. Marginal gap was measured by scanning electron microscope during three stages of crown fabrication: before degassing, after degassing and after glazing. The mean measurements in collarless group were 21.4±13.4, 2I.4±14.9 and 21.9±11.9 u_m, respectively, and in-group with collar 24.7±11.4, 24.0±! 1.5 and 26.6±11.7 urn, respectively. Two- way ANOVA revealed no significant difference in the mean values between two groups and among different stages of crown fabrication. The results of this study showed that base metal alloys did not distort during crown fabrication and metal collar had no effect on the amount of marginal opening (gap).

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Statement of Problem: Total removal of tissues and remnant microorganisms as well as canal shaping are the essential objectives of endodontic therapy. A successful endodontic treatment is obtained through Shilder’s principals, however complete observation of this technique using stainless steel files manually is problematic and time-consuming. Modern technology, in order to eliminate such problems, has presented new facilities such as Nickel-Titanium (NiTi) files and engine driven instruments.

Purpose: The aim of this in-vitro study was to compare the canal debridement efficiency of three engine driven instruments: Rotary, Reciprocal and Vertical.

Materials and Methods: In this experimental study, 60 mesial roots of human first and second mandibular molars were divided into three groups randomly. In each sample, one canal was considered as case, the other one as control. Files used in Reciprocal and vertical groups were of handy Ni-Ti type and in rotary group, rotary Ni-Ti files were used. After debridement, the roots were sectioned at 3mm and 5mm from anatomic apex, stained and examined under light microscope. Comparison criteria between case and control groups were based on residual debris and predentin and the level of root canal preparation and shaping after debridement. Data were subjected to kruskal-Wallis non-parametric test.

Results: There was no significant difference between the efficiency of debridement at 3mm and 5mm sections between all groups. But difference in time consumption was significant ranked from the shortest to the longest as rotary, reciprocal and vertical.

Conclusion: The efficiency of debridement between the three automated instruments was approximately equal, however the instrumentation time was different between three groups. Rotary system was the fastest one, as compared with reciprocal (second) and vertical (last). It may be concluded that rotary system has a superiority over the other two groups in conventional root canal therapies.

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Statement of Problem: Reduction of orthodontic therapy treatment time is considered an important goal in the management of malocclusion in adult patients. Corticotomy- facilitated orthodontic treatment may be considered an intermediate therapy between orthognatic surgry and conventional orthodontics for reducing treatment time.
Purpose: This study was undertaken to evaluate and compare the rate of tooth movement of upper canine following corticotomy with conventional method.

Materials and Methods: Ten young adult patients, 17-25 years old was selected through sequential sampling procedure in orthodontics department of Shiraz Dental School. The patients exhibited different orthodontic problems and needed extraction of premolars. Following extraction of premolars and initial phase of orthodontic treatment, corticotomy were performed unilaterally on buccual and palatal sides of extraction area as described by Takami. The other imoperated sides were used as control. After subsiding the resultant inflammation, the activated NiTi spring was used and measurement of the amount of tooth movement were assessed by using Rugae as reference point. The panoramic radiographs were super imposed for evaluation of canines tipping. For analyzing the results, Kolmogorou- simirnov and t.tcst were used.
Results: The rate of canine tooth movement was much greater in the corticotomy sides than the unoperated (control) side (P=0.015). This was especially significant at the end of first week of tooth movement (P=0.000). Comparing the two sides, the amount of canine tipping was much lesser in corticotomy group than the control group (P=0.046). There was no significant difference concerning the anchorage loss between the two groups (P=0.410).
Conclusion: Corticotomy procedure had a positive effect on the rate of tooth movement with less tipping of the canines comparing to conventional orthodontic treatment. To get more benefit from this procedure, it is recommended to select those patients who do not need canine alignment after premolars extraction, such as bimaxillary dento alveolar protrusions.

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Statement of Problem: The pulp may be exposed during remove of caries or by traumatic and iatrogenic injuries. The material used to DPC, must be biocompatible, scalable and prevent bacterial leakage.Furthermore, it is better to stimulate dentinogenesis. Calcium hydroxide is most usual material for DPC. But it cannot provide a suitablcbiologic seal. Mineral irioxide aggregate (MTA) is also a suitable material for DPC.
Purpose: The aim of this study was to compare the clinical success of DPC done with MTA or calcium hydroxide cement.

Materials and Methods: In this study eighteen posterior teeth without previous spontaneous pain that involved mechanicaly exposure was randomly selected and capped with MTA or calcium hydroxide. These teeth were evaluated by clinical vitality test and radiograph after 3 and 12 months, and patients were questioned about irritative or spontancus pain in this period. Statistical analysis was carried out by Usher exact
test (a-0.05).
Results: This study showed that in calcium hydroxid groud three had irreversible pulpitis and two teeth had symptom and signs of reversible pulpitis. While, In MTA group all cases were normaL and no clinical sign was evident.
Conclusion: MTA exhibited better results than calcium hydroxide cement for the capping of the pulp in human

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Background and Aim: Preserving canal curvature during different phases of canal preparation is an important point. In Endodontic therapy all efforts are made to prepare canal in a way that final canal follows the primary canal curvature. The purpose of this study was to evaluate the efficacy of root canal preparation performed by students at Endodontic Department of Dental School, Tehran University of Medical Sciences.

Materials and Methods: In this retrospective study, classic method of step- back technique was investigated for preserving canal curvature in mesial roots of first mandibular molars and mesiobuccal roots of first maxillary molars between years 2000 and 2004. A randomly selected sample of 400 dental patient records was investigated by 4 observers (Endodontic department professors), searching for procedural errors. A clear explanation sheet of curvature preservation and procedural errors such as ledge formation, apical foramen transportation, zipping and stripping and a questionnaire were prepared for observers. The observers went through reliability test and kappa value for agreement between every two observers. The results were above 0.8. Data were analyzed by EPI6 statistical computer program, using Chi-Square and Fisher exact test with P<0.05 as the limit of significance.

Results: This study consisted of 152 first maxillary molars and 248 first mandibular molars. The prevalence of curvature preservation in mesial root of first mandibular molars and mesiobuccal root of first maxillary molars were 38.5% and 47.6% respectively. Procedural errors detected consisted of 33% ledge formation, 26.1% apical foramen transportation, 1.8% zipping and 4.1% stripping for mesial root of the first mandibular molars. The results for the first maxillary molars were 27%, 19%, 3.2% and 3.2% respectively.

Conclusion: The study results revealed the efficacy of endodontic education and the proficiency of junior and senior students in preparing curved posterior root canals. The results obtained in this retrospective study are comparable to prospective studies.

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Background and Aim: The need for recrimping precrimped stainless steel crowns by the dentist in clinic is controversial. This study aimed to evaluate the rate of marginal circumference and marginal thickness change of precrimped stainless steel crowns after recrimping.

Materials and Methods: In this experimental study, 30 primary photos were taken from margins of 30 S.S.Cs (3M, Ni-Cr) related to tooth 85 with a digital camera fixed at a determined distance. Margins of crowns were crimped by 114 and 137 pliers with a controlled force (0.2 N) and then 30 secondary photos were taken in the same conditions. The circumference of crown margins in primary (group A) and secondary (group B) photos were assessed by a digitizer system. Comparing the circumferences of crown margins in primary and secondary photos showed a significant decrease after crimping. Thickness of 30 random points on the crown margins of a crown similar to mentioned cases was measured by SEM (×150). Then similar procedures including taking a primary photo, crimping and taking a secondary photo was done for the sample crown. After significant reduction in margin circumference, thickness of 30 other random points on the crown margin were measured by SEM. Data were analyzed by paired sample t-test with p<0.05 as the limit of significance.

Results: The mean marginal circumference of precrimped stainless steel crowns was reduced by 7.3% which was significant (P<0.001). On the other hand the mean marginal thickness of sample stainless steel crown showed 18µ increase.

Conclusion: According to the results of this study, marginal circumference of precrimped stainless steel crowns (3M, Ni-Cr) showed a significant decrease after crimping. It is concluded that crimping the stainless steel crowns even for precrimped ones seems necessary.

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Background and Aim: Many methods and techniques of canal preparation work well in large and relatively straight canals. However, in severely curved canals, the complexity increases markedly, and techniques rendering good results in usual cases may be unsuccessful. The aim of this study was to compare the effect of five root canal preparation techniques on original canal anatomy in simulated severely curved canals.

Materials and Methods: In this experimental in vitro study, 100 simulated canal blocks with similar hardness were made from polyester. The degree of curvature was 45º with a radius of 2.55 mm and a straight part of 8mm. The blocks were prepared with five different techniques (20 canals in each group) as follows: 1-Stepback 2- Passive step back 3- Balanced force using flex-R files 4- Balanced force using Ni-Ti hand instruments 5- Hybrid using a rotary Ni-Ti system (XtremRace). Digital photographs were taken from pre- and post instrumentation colored canals. Then images were superimposed and analyzed by an image editing software. The amount of removed material from the inner and outer canal walls was measured at five levels: 1-The canal orifice (O) 2-The halfway between the orifice and the beginning of the curve (HO) 3-The beginning of the curve (BC) 4-The apex of the curve (AC) and 5-The endpoint of preparation (EP). Additionally, the time of instrumentation, instrument failure and changes in working length were recorded. Data were analyzed by ANOVA and Kruskall-Wallis tests with p<0.05 as the limit of significance.

Results: Mean transportation was towards the outer aspect of the curve at the EP in all canals but there were no significant differences between the studied groups. At the BC point, all of the canals were transported towards the inner aspect of the curve and there were significant differences for both transportation values & direction among different groups. The highest amount of transportation was in step back and the lowest, in hybrid group. The highest transportation value was in step back and the lowest in balanced force group. Fractured and deformed instruments were observed in Flex-R files. The shortest canal preparation time was seen in XtremRace and the slowest, in Passive step back groups (P<0.001).

Conclusion: Based on the results of this study, changes in canal curvature were less with techniques using nickel titanium instruments and the fastest technique with least transportation was XtremRace.

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Background and Aim: The microbial cause of dental caries has been proved among its multifactorial etiologies. The prevention and control of dental caries is very critical because of high prevalence and cost especially in high risk patient such as xerostomia. Based on the world attraction to traditional treatment and importance of drug extraction of natural materials and plants, in this in vitro study effect of hydroalcoholic extract of Salvia officinalis and Pimpinella anisum which were very useful in traditional treatment of mouth and teeth disease has been determined against cariogenic bacteria.

Materials and Methods: In this experimental study, hydroalcoholic extracts have been prepared from Salvia officinalis and Pimpinella anisum with maceration method. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated with broth macrodilution method. Data were analyzed with Mann-Whitney test.

Results: Minimum Inhibitory Concentration for Salvia officinalis and Pimpinella anisum for streptococcus mutans were respectively 6.25 and 12.5 µg/ml, for Lactobacillus rhamnosus were 1.56 and 12.5 µg/ml and for Actinomyces viscosus were 12.5 and 50 µg/ml.

Conclusion:Both extracts had growth inhibitory effect on all three bacteria. Salvia officinalis had significantly greater effect on inhibition of growth of all three bacteria. Both extracts had bactericidal effect in the range of concentration.

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Background and Aims: The seal provided by a root canal filling may be compromised by post space preparation. The aim of this study was to compare coronal microleakage around cast posts and prefabricated pins.

Materials and Methods: Thirty-eight extracted single-rooted, maxillary human teeth were prepared with step back method and filled with gutta-percha and sealer. After removing 8 mm of coronal gutta-percha with peeso-reamer drills #2 in twenty canals, the teeth were divided into three groups: cast post & core, prefabricated pin,  and gutta-percha (without any post or pin). After thermocycling, the samples were immersed in India ink for seven days. Finally, the specimens were cleared and the coronal microleakage of dye was then measured by the stereomicroscope. The data were analyzed by One-way ANOVA and Tukey HSD tests.

Results: According to the results, the mean dye penetration in cast posts, pins, and group without post or pin was 3.3 (0.39), 5.2 (0.47), and 7.2 (0.15) mm, respectively. There was no statistically significant difference between the groups (P>0.05).

Conclusion: Considering the importance of adequate filling of crown for prevention of microleakage, the method for coronal filling must be selected with caution. According to the results of this study, no significant difference between microleakage of cast posts and prefabricated pins was observed.

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  Background and Aims: The purpose of this study was to evaluate the tissue responses to octacalcium phosphate (OCP) and calcium hydroxide (CH) used as direct pulp capping (DPC) materials in cat teeth.

  Materials and Methods: 72 premolar teeth of 9 cats were selected and divided into 3 groups (Two experimental and one control group). After the cats had been anesthetized, the pulp were exposed and capped directly with OCP, CH or no capping material as control group. The cavities of all three groups were filled with Glass ionomer cement (GI). Histological evaluations were performed at two, four and eight weeks after pulp capping. After tissue preparation procedures, paraffin blocks were prepared. After preparation and staining of the sections, the relevant variables were measured by optical microscope. The results were analyzed using Mann-Whitney U and Chi-square tests ( α =0.05).

  Results: Two weeks after pulp capping, all specimens in three groups showed mild to sever inflammation. The formation of hard tissue (dentinal bridge) at in the exposed areas of the experimental groups was more noticeable for calcium hydroxide than that of octacalcium phosphate group. These differences were statistically significant (P<0.001). At four weeks, hard tissues were observed in both groups which were more evident for the CH group and there were statistically significant difference between two experimental groups (p<0.003). At eight weeks, continuous hard tissues were observed in both groups and there were no statistically significant difference between them (P>0.05), but hard tissues continuity were better for in the OCP than that of the CH.

  Conclusion: It seems that the formation of hard tissue in CH because of its porosities had a worse percentage in sealing of the pulp than the OCP .

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Background and Aims: One of the most important consequences of the rapid growth of urbanization has been the unequal distribution of urban service specially health care services and escalation of social inequality of citizens. Therefore, this study was aimed to analyze the spatial distribution of dental centers in Isfahan from the perspective of spatial equity.
Materials and Methods: This analytical cross-sectional study was conducted in 2023 in Isfahan city. The required data including the population of the fifteen districts of Isfahan city, the data of the geographic municipal areas and the dental centers of Isfahan city were put into Excell. The population data were gathered from the statistical yearbook of population and housing. The dentists’ data were gathered from the Medical Council. Addresses of the dental centers were fed into the Google earth and were found on the traffic map of Isfahan. Using the Arc GIS 10.8 software and based on the Geographic Information System concepts, the spatial justice was analyzed. Moran's autocorrelation index was used to determine the distribution pattern (cluster, scattered, random). Hot spot analysis and nearest neighbor distance (centers in this radius would have more access) were used. Access ratios were analyzed using the ratio of population to the distance of each parcel to the dental centers and then were categorized as privileged to, semi and unprivileged.
Results: Z-score of Moran test was more than the expected score of 2.58 at 0.01 level of significant, indicating the cluster pattern of dental settings distribution in Isfahan. Moran's index (0.076) was much more than the expected equity coefficient (-0.000055), indicating again the cluster pattern of distribution which was not favorable in terms of spatial justice. The nearest neighbor distance analysis indicated that by moving from the center of the city to the outskirts of the city, access to dental centers decreased. Access analysis determined that privilege areas of the city were located mostly in central municipal areas and about 60% of these areas were limited to three municipal regions. Also, about 63% of the city area were categorized as unprivileged.
Conclusion: Distribution of dental centers in the city of Isfahan is not an equal distribution and the dental settings are mostly concentrated in the central areas of the city, not necessarily in high populated areas. There, this pattern necessitates the proper planning to establish dental settings in deprived and high-populated parts of the city.