فهرست مطالب

Journal of Dental School
Volume:30 Issue: 1, 2012

تاریخ انتشار: 1390/12/17
تعداد عناوین: 9

فارسی
English

انتخاب همه

Failure Rate of Dental Procedures Performed under General Anesthesia on Children Presenting to Mofid Pediatric Hospital during 2010-2011

Dr. M. Biria, Dr. Gh. Ansari, Dr. Z. Taheri Page 1

Background And Aim
Extensive dental treatments for young healthy and medically compromised children are performed under general anesthesia in a daily basis. Considering the side effects of sedatives and anesthetic drugs and also the high risk of dental caries in this group of patients, it is especially important to decide the safest and the most cost beneficial treatments. This study aimed at clinical evaluation of the failure rate of various dental procedures performed under general anesthesia on children presenting to Mofid Pediatric Hospital in Tehran during 2010-2011.
Materials And Methods
This descriptive cross sectional study was conducted on a total of 104 patients who received dental treatments under general anesthesia in Mofid Pediatric Hospital and a minimum of 6 months had been passed from their treatment. Dental examination was performed on a dental chair using dental mirror and a probe in the out-patient dental clinic of Mofid Pediatric Hospital. Recorded information included all types of treatment failures occurred in patients that were registered in especially prepared forms. Overall difference in failure rates was calculated using Chi square test while multiple logistic regression test was used to investigate the effect of different factors on the failure rate of treatment modalities.
Results
Our study results indicated that stainless steel crown (SSC) was the most successful treatment with the lowest failure rate (1.5%). SSC had a significantly lower failure rate compared to amalgam (7.9%) and posterior composite restorations (9.9%) (P=0.003 and P=0.000, respectively). Composite buildup of the anterior teeth had the highest failure rate (22.4%) among all types of anterior restorations (11.6%) (P=0.009). The failure rates of both pulpectomy and pulpotomy procedures were found to be reasonably low rating at 0.8% and 1.1%, respectively.
Conclusion
The highest failure rate belonged to anterior teeth build-ups. Teeth restored with SSC had the highest success rate indicating it as the treatment of choice for badly carious posterior teeth of children who require dental treatments under general anesthesia.

Abstract View Paper Original: Persian
In Vitro Antimicrobial Activity of Propolis in Comparison with Calcium Hydroxide against Enterococcus Faecalis

Dr. Z. Ahangari, Dr. G. Eslami, Dr. S. Ghannad Page 9

Background And Aim
Propolis, a natural product of the honeybee, is currently used as an anti-inflammatory and antimicrobial agent. Using different antibacterial agents is an important step to reduce the number of microorganisms within the root canal and improve the endodontic treatment prognosis. The present in vitro study investigated the antibacterial efficacy of Propolis against Enterococcus faecalis compared to calcium hydroxide.
Materials and Methods
In this experimental study, 42 single-rooted human teeth were selected and their smear layer was completely removed after access cavity and canal preparation. After infecting the prepared canals with Enterococcus faecalis species, negative control group was used during sterilization period and in two groups of 18 each, canals were filled with 30%propolis extract and calcium hydroxide, respectively. No material was added to the positive control group. The specimens were stored in CO2 incubator for 72 hours, 1 week and 1 month and afterwards, samples were taken from inside the canals and Enterococcus faecalis colonies were counted. Number of colonies at different time intervals was statistically analyzed using Kruskal-Wallis test. Mann-Whitney U test was used to compare the number of colonies after using the understudy medicaments.
Results
Number of colonies was 55,000±46,368.09 and 43,333.33±48,027.077 after incubation for 72 hours and using 30% Propolis extract and calcium hydroxide, respectively. After 1 week incubation, number of colonies was 166.67±408.25 in the Propolis group and zero in the calcium hydroxide group. No colonies were observed after 1 month incubation in both groups. No significant differences were noted between two medicaments at different time intervals.
Conclusion
In general, antimicrobial activity of Propolis against Enterococcus faecalis species was comparable with that of calcium hydroxide at different time intervals. Therefore, it can be used as an alternative natural material for disinfection of canals during endodontic treatment.

Abstract View Paper Original: Persian
The Micro shear Bond Strength of Composite-Composite after Salivary Contamination

Dr. Z. Jaberi Ansari, Mohasmmadpour Page 17

Background And Aim
Contamination leads to decreased bond strength causing failure of restorative treatments. The present study evaluated micro-shear bond strength of composite-composite after saliva contamination and searched for the best method to maintain primary bond strength.
Materials and Methods
In this in-vitro trial, specimens made by Z100 composite resin were divided into 7 groups each containing 15 samples and were prepared as follows: Group 1- Control (no contamination), Group 2: Saliva+air drying, Group 3- Saliva+rinsing+ air drying, Group 4- Saliva+ rinsing+ air drying+ etching, Group 5- Saliva+ rinsing+ air drying+ etching+ bonding, Group 6- Saliva+ alcohol, and Group 7- Saliva+ 0.5 mm removal of composite+ rinsing + air drying. Z100 composite was added through tiny tubes (0.7x1 mm) to the prepared surfaces and cured. The microshear bond strength was then determined. Data were analyzed using ANOVA and Tukey’s multiple comparison tests.
Results
Mean and standard deviation of the microshear bond strength was 23.0±3.60 MPa in group 1, 11.71±2.49 MPa in group 2, 17.60±4.25 MPa in group 3, 21.84±6.34 MPa in group 4, 21.25±7.58 MPa in group 5, 21.65±5.53 MPa in group 6 and 17.34±5.95 MPa in group 7. Differences between groups 1 and 2 (P<0.0001), 2 and 4 (P<0.0001), 2 and 5 (P<0.001) and 2 and 6 (P<0.0001) were statistically significant.
Conclusion
The results of this study showed that air drying of the surface after saliva contamination decreased microshear bond strength significantly. All cleansing methods increased bond strength of the specimens up to thatof the control group.

Abstract View Paper Original: Persian
Evaluation of the Compressive Strength of Hybrid and Nanocomposites

Dr. M. Moezzyzadeh Page 23

Background And Aim
Nowadays, composite restorations have gained more popularity and are widely used due to their high esthetic properties, rapid application, ease of use and low costs. There are various composite resins of different brands available in the market and it is necessary to find the most favorable one in terms of reliability and long term prognosis. The present study aimed at evaluating and comparing the compressive strength of hybrid and nanocomposites.
Materials and Methods
In this experimental in-vitro study 4 different types of composite resins were used as follows: Group 1- Filtek Z 250 (3M) (hybrid composite) Group 2- Filtek Supreme (3M) Group 3-Gradia Direct X(GC) Group 4-Herculite XRV Ultra (Kerr Hawe)composite resins (groups 2, 3 and 4 are nanocomposites). Twelve samples were made in stainless steel molds of 4mm diameter and 6mm height of each composite. Following photopolymerization of cylindrical samples using Radi plus light curing unit (SDI limited), the specimens were stored in distilled water at 37°C for 48 hours. The specimens were subjected to compressive stress test using Mechanical Testing Machine (Zwick/Roell) at cross head speed of 0.5 mm/min. One way ANOVA and Tukey’s Post-hoc tests were employed for statistical analyses and determining level of significance.
Results
The obtained results were as follows: Group 1: 362.51 group 2: 266.70 group 3: 268.72 and group 4:275.75 Newton. Compressive strength of group 1 (Filtek Z 250) was higher than other three groups and it was statistically significant (P<0.05). No statistically significant difference was detected among groups 2, 3 and 4.
Conclusion
Hybrid composite showed more compressive strength than nano composites.

Abstract View Paper Original: Persian
The comparison between palatal connective tissue graft as a membrane with collagen membrane in combination with Bio-Oss and PRGF for the treatment of intrabony defects: (A Randomized Clinical Trial)

Dr. H. Moghaddass, Dr. M. Kadkhodazadeh, : Dr. A. Pezeshkfar Page 29

Background And Aim

This randomized clinical trial was aimed at comparing the outcomes of palatal connective tissue+ Bio-Oss + PRGF versuscollagen membrane + Bio-Oss+ PRGFin the treatment of intrabny defects.

Materials and Methods

Fifteen patients affected by chronic periodontitis were enrolled. Each patient had at least two intrabonydefect (≥3mm). They were randomly assigned into two groups: patients treated i)with collagen membrane+PRGF+Bio-oss (control group) and ii) with palatal connective tissue as membrane + PRGF+Bio-Oss (experimental group). Clinical and intrasurgical examinations included probing depth(PD), clinical attachment level(CAL),gingival recession(GR),defect fill(DF), alveolar crest level(AC) and defect resolution(DR) were measured at baseline and after 6 months with re-entry surgery. Statistical analysis was performed usingTwo-way Repeated Measure ANOVA and Wilcoxon.

Results

After 6 months, all of the evaluated clinical parameters showed statistically significant changes from baseline within each group (p< 0/05). The test group showed a significantly smaller amount of gingival recession as compared with control group.(0/8mm versus 1/7mm respectively; P<0/05) But there were not any statistically differences in other clinical parameters between the test and control groups(P>0/05): pocket depth reduction (3/7mm versus 3/5mm), clinical attachment gain (1/8mm versus 1/6mm), alveolar crest loss (1/8mm versus 1/7mm), defect fill(2/3mm versus 2/2mm) and defect resolution (4/1mm versus3/9mm).

Conclusion

According to the results obtained from this study it can be suggested that clinical effects of application of palatal connective tissue as a membrane and collagen membrane, in combination with Bio-Oss and PRGF in treatment of vertical bone defects, did not have any statistical significant differences except for gingival recession that was statistically smaller in connective tissue group.

Abstract View Paper Original: Persian
The effect of implant position on the retention and stability of mandibular implant-supported overdentures

Dr. Sj. Sadr, Dr. A. Hadi, Dr. A. Saboury, Dr. M. Mahshid, Dr. A. Akbarzadeh Baghban Page 40

Background And Aim

The standard of treatment of edentulous people is implant retained overdenture. The aim of this study was to compare the effect of different implant location (ABDE, 6AE6, 6BD6) on the retention and stability of mandibular implant overdenture with ball attachment.

Materials and Methods

An experimental study was designed. An acrylic resin model of edentulous mandible with six implant in the location of first molars, first premolar and between lateral incisor and canine on the left and right side was fabricated. A metallic overdenture was fabricated precisely adapted to the model and attached to a Zwick testing machine (crosshead speed of 51 mm/min). The ball attachments were screw in three ways. First the balls in ABDE, then ball in 6AE6 and then balls in 6BD6 position were screwed. Dislodging tensile forces were applied in three vertical, oblique, anterior-posterior directions for each sample. For each of these three situations, five tests were done. The maximum dislodging force was measured. Normal distributions of data were analyzed with Shapiro-Wilk test. Levene test analazed the variances. A Three-way ANOVA test was employed followed by Tukey’s test.

Results

The amount of vertical load is significantly higher than the oblique and Ant-post load (P<0.001). The amount of ant-post load is signifivantly higher than the oblique load (P<0.001). The average of MDF is significantly higher in 6BD6 position (P<0.001). This average is also signifivatnly lower in ABDE position (P<0.001). The amount of measured force in ABDE and 6BD6 position was the least and the most respectively (ABDE=64.51 N and 6AE6=66.06 N). Vertical and oblique dislodging force are the minimum and maximum measured forces respectively (mean vertical= 87.95 N, mean Lateral= 48.1 N and mean Ant.Post= 63.5 N)

Conclusion

Lateral and Ant.Post dislodgment values are higher in 6BD6 and 6AE6 respectively. In vertical dislodgment the retention values in the most in 6BD6 position. Vertical retention in higher than lateral and Ant.Post retentions. The more posterior position the distal implant the more the retention and stability.

Abstract View Paper Original: Persian
Comparison of ball retained over denture's retention the most anterior and posterior implant positions at symphysis

Dr. Sf. Tabatabaian, Dr. A. Saboury, Dr. Zs. Sobhani Page 50

Background and Aim

The aim of this study was tocompare retention of implant-tissue supported overdentures with ball attachments in the most anterior and posterior implant positionsat symphysis.

Materials and Methods

An acrylic resin model of edentulous mandible with no undercuts was fabricated. Two pairs of implants, two by two, were placed symmetrically in the most anterior and posterior positions at symphysis.Two were placed 5mm from midline in anterior position while two others 5mm infront of mental foramina site in posterior position. A metallic overdenture was made on the model precisely. Then an over denture housing was prepared on the frame work and joined to it. The ball abutments were screwed on the pair of implants in different positions and the complex of attachment housing and clinical insert, were attached into the over denture housing. Five samples were tested for each position. Zwick testing machine loaded and measured tensile forces invertical direction for each sample. Maximum Dislodging Force (MDF) was recorded at the moment of completed attachment of over denture from the model. Independent sample T-test was performed to analyse the data and results reported by confidence coefficient of 95%.

Results

There was no statistically difference in retention of implant-tissue supported over dentures in the most anterior and posterior positions of implants at symphyseal region (P>0.05).

Conclusion

The amount of retention is the same in the most anterior and posterior positions of implans at symphysis.

Abstract View Paper Original: Persian
Evaluation of Tissue Interaction and Orthodontic Tooth Movement Following Application of FDBA and DFDBA

Dr. M. Seifi, Dr. N. Shamloo, Dr. M. Mirzaei Page 57

Background and Aim
The purpose of this study was to investigate the histologic interaction between two different allografts and first premolar root; following orthodontic tooth movement.
Materials and Methods
Sample consisted of four male dogs. In each animal, four defects were created at the mesial aspects of the maxillary and mandibular first permanent premolars. The defects were filled with DFDBA or FDBA equally. NiTi closed coil with 150 gr force was used for mesial movement of the first premolar. When the experimental teeth were had been moved about halfway into the defect spaces i.e.nine weeks, the animals were sacrificed and the area of interest were harvested. The first premolar root and adjacent tissues were histologically evaluated. Tooth movements were analyzed using paired t test.
Results
The findings demonstrated that it was possible to move a tooth into a defect, filled with DFDBA or FDBA with the same rate of tooth movement. Mean tooth movement in DFDBA and FDBA was 2.6±0.11 mm in DFDBA and 2.4±0.12 mm in FDBA. Apical root resorption occurred on the pressure sides in both groups.
Conclusion
These findings indicate that FDBA and DFDBA could be a biocompatible bone substitute into bone defects subjected to orthodontic tooth movement.

Abstract View Paper Original: Persian

علمی مصوب

Journal of Dental School

مجله دانشکده دندانپزشکی

فصلنامه پزشکی به زبان انگلیسی

آخرین شماره | آرشیو

eISSN: 4351-2645

صاحب امتیاز:

دانشگاه علوم پزشکی شهید بهشتی

مدیر مسئول:

سورنا وهابی

سردبیر:

دکتر زهرا قربانی

تلفن نشریه: ۰۲۱-۲۶۷۰۸۳۹۵

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فهرست مطالب

Journal of Dental School Volume:30 Issue: 1, 2012

Journal of Dental School

مجله دانشکده دندانپزشکی

Journal of Dental School
Volume:30 Issue: 1, 2012