Vol 6, No 3 (2009)
Proceeding Abstracts
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Objective:
The aim of the present study was to evaluate the effect of two impression materials on the shear bond strength of porcelain to immediately sealed dentin.
Materials and Methods:
Smooth dentin surfaces of 45 extracted premolars were immediately sealed with Adper Single Bond adhesive agent. Forty-five porcelain specimens were also prepared. The teeth were divided into one control and two experimental groups. In control group, an adhesive layer to dentin was applied and feldspathic porcelain specimens were bonded to dentin with Relay X dual-curing cement. In one experimental group, the teeth were embedded in condensational silicon (Speedex) and in the other group in polyether (Impregum Soft) impression materials before bonding the porcelain specimens as in the control group. Shear bond strengths were measured using a universal testing machine. Fracture modes were evaluated under a stereomicroscope. Data was analyzed using oneway ANOVA, Tukey, and chi-square tests (α=0.05).
Results:
No significant differences existed between bond strength of the control and condensational silicon groups (P=0.31). Bond strength was significantly lower in polyether group in comparison with the control (P<0.0005) and condensational silicon groups (P=0.002).
Conclusion:
Contamination with polyether impression material adversely affects the shear bond strength of porcelain to immediately sealed dentin.
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Objective:
The gingival crevicular fluid (GCF) is an inflammatory exudate found in the gingival sulcus. The forces exerted during orthodontic treatment cause distortion of the periodontal ligament (PDL) extra-cellular matrix, resulting in some biological features that can lead to modification of both GCF volume and its components. The present study investigated the effect of orthodontic tooth movements, specifically canine retraction, on the volume of GCF exudate.
Materials and Methods:
Fourteen upper and lower canines of patients with different Angle classifications were selected for the study. After extraction of the first premolars, the canines were subjected to orthodontic distal retraction. GCF was sampled from mesial and distal gingival crevices of each canine separately at baseline, 1 hour, 7 days, 14 days, 21 days, and 28 days after the application of the orthodontic distal retraction. GCF volume was determined by means of an electronic device.Results:
GCF volume at tension sites was slightly greater after 21 and 28 days compared to other observation time points. At pressure sites, GCF volume was slightly greater after 28 days compared to other observation time points. None of the observed differences, however, was statistically significant (P>0.05).Conclusion:
Orthodontic tooth movement, namely canine retraction, does not significantly increase the volume of GCF exudate. The slight increase in GCF volume could be due to a slight degree of gingival inflammation. -
Comparison of Partial- and Full-Mouth Examination in Periodontal Assessment Among Untreated Patients
Objective:
Whole-mouth examination is generally considered as a gold standard for exact periodontal disease assessment. Partial mouth examination also has sometimes been used for this purpose, but its efficacy has been questioned. With regard to symmetric destruction hypothesis of periodontal disease, the present study investigated the efficacy of partial- mouth examination as an alternative for whole-mouth examination.
Materials and Methods:
Eighty subjects aged between 20 to 61 years old (mean 41 years old, 47 males & 33 females) with periodontal disease at different stages of severity and extent (Mild, Moderate, Severe) were examined. Plaque index (PI), gingival index (GI), and papillary bleeding index (PBI) were assessed in whole-mouth except third molars, and were compared with four defined partial-mouth examinations on teeth in Upper Right/Lower Left, Upper Right/Lower Right, and Upper Left/Lower Left quadrants, as well as on Ramfjord teeth. T-test and intraclass correlation coefficients (ICC) served for statistical analysis.Results:
Differences between mean PI, GI, PBI in partial and whole-mouth examination were not statistically significant (P>0.05) and agreement between partial- and wholemouth assessment was generally greater than 0.9 (ICC>0.9). However, upper right and lower left quadrants examinations showed the most consistency and conformity with whole-mouth examination.Conclusion:
partial-mouth examination procedure especially in upper right and lower left quadrants might be considered as an acceptable alternative to whole mouth assessment. Partial-mouth examination procedure conserves time, limit cost and reduce the patient and examiner's fatigue while providing maximum clinical information. -
Objective:
Various techniques of composite placement have been used to decrease microleakage around the composite restorations. Due to controversial results, the present study was conducted to investigate the effect of different placement techniques on microleakage in class V composite restorations.
Materials and Methods:
Sixty class V cavities were prepared on the buccal and lingual surfaces of 30 extracted healthy human premolars. The teeth were randomly assigned to five groups, and were restored with composite resin, using five different techniques: (1) horizontal increments (gingivo-occlusal), (2) horizontal increments (occluso-gingival), (3) oblique increments (gingivo-occlusal), (4) oblique increments (occluso-gingival), and (5) bulk placement. After thermocycling, 500 cycles of between 5°C and 55°C (SD=2), and immersion in 0.5% alcoholic Fuschin, the teeth were then sectioned and evaluated for microleakage by stereomicroscope (×16). Microleakage was scored on a 0-4 scale. Nonparametric Mann-Whitney U and Kruskal-Wallis tests served for statistical analysis.Results:
Gingival margins of class V cavities showed microleakage regardless of the placement technique. Oblique (gingivo-occlusal) technique showed less microleakage in gingival margins of the restorations compared to bulk technique. The least microleakage in gingival margins was related to group 3 while the most microleakage was related to group 5. Bulk and oblique (gingivo-occlusal) incremental techniques produced significantly different rate of microleakage (P<0.003). Group 3 showed the most difference with groups 5, 1, 2, and 4, respectively.Conclusion:
Among four incremental techniques, the gingivo-occlusal oblique filling technique resulted in a lower leakage value, when compared to the bulk filling technique. -
Objective:
In dental and medical education, information and communication technology (ICT) has been playing an important role and its use is rapidly increasing. In developing countries, however, information technology is still only available to a minority of health professionals. The present study aimed to assess the level of computer use among dental undergraduate students pursuing their career at a private dental institution in India.
Materials and Methods:
The study population comprised dental undergraduate students from first to fourth year pursuing their career in a private dental institution of India. Information technology practices were assessed using a questionnaire that consisted of 14 questions.Results:
In total, 247 students with an overall response rate of 66% participated in the study. Only 58.3% of the study population mentioned that they had access to computers. Students from preclinical years reported to be competent in IT skills more frequently than the clinical year students (chi square test, P=0.007). Compared to women, men used computers more regularly both for academic activities (P=0.082) and personal use (P=0.006). Similarly, students of clinical years used computers more than preclinical students for both purposes (academic activities, P=0.045; personal use, P=0.124).Conclusion:
The present study revealed that computer literacy of Indian dental undergraduate students was comparable with students of other countries whereas accessibility of IT sources was poor. Expansion of computer-assisted learning which requires careful strategic planning, resource sharing, staff incentives, active promotion of multidisciplinary working, and effective quality control should be implemented. -
Objective:
The aim of this study was to assess skeletal relapse in patients who underwent mandibular setback by bilateral sagittal split ramus osteotomy (BSSRO) and osteosynthesis wiring techniques.
Materials and Methods:
In this semi-experimental study, 10 patients (8 women, 2 men) with 3-8 millimeters overjet underwent mandibular setback with BSSRO, osteosynthesis wiring and inter maxillary fixation (IMF) techniques for 6-8 weeks. They were studied before (T0), immediately after (T1), and 6 months after surgery (T2) using clinical and cephalometric indices. Then, the maximum changes occurred in sagittal, rotational and vertical planes were evaluated in three time intervals (T1-T0), (T2-T0), and (T2-T1). Wilcoxon paired test was used as a statistical approach for data analysis.Results:
The highest degree of relapse occurred in the sagittal plane in mandibular setback surgery with BSSRO and osteosynthesis wiring and IMF techniques. The degree of relapse was irrelevant of setback. In addition, no patient showed the amount of relapse warranting another surgery after six months.Conclusion:
BSSRO surgery with osteosynthesis wiring and IMF provides acceptable stability in mandibular setback. -
Objective:
Periodontal diseases are common in the society and some researchers suggested an association between rheumatoid arthritis (RA) and periodontal diseases. The present study was carried out to evaluate the so-called association in Iranian adults.
Materials and Methods:
In this case-control study, the samples were recruited from patients referred to Loghman Hospital, Tehran, during 2004-2005. Fifty patients with RA aging 27-50 with no other systemic diseases were matched for sex, age, smoking, and oral hygiene status with healthy control samples. The drugs affecting periodontium status were excluded from the study. Clinical attachment loss (CAL) index was measured by a scaled Williams periodontal probe in both groups at four surfaces, and the type of periodontitis was determined. Chi-square, Mann-Whitney U, and t-student tests served for statistical analyses.Results:
In RA group, 30 patients (60%) had moderate to severe periodontitis while in control group the condition was detected among eight patients (16%). Significant difference existed between the two groups in terms of periodontitis stage (P<0.001). Median of the CAL scores was 4.5 mm and 0 mm in RA and control patients, respectively, with significant difference (P<0.001).Conclusion:
The results suggest higher potentiality for moderate to severe periodontitis involvement among RA patients, possibly due to similar nature of the two diseases. Periodontal assessment of RA patients is necessary for early diagnosis and consequent treatment. -
Objective:
The aim of this study was to investigate the translucency of resin-modified glass-ionomer cements (RMGIC) and polyacid-modified composite resin (PCMR) over a period of one year.
Materials and Methods:
The study was done on three RMGIC (Fuji II LC, Photac-Fil Aplicap and Vitremer) and one PCMR (Dyract). A conventional GIC (Fuji Cap II) and two composite resins (Tetric and Z 100) were used for comparison. Five discs approximately 5 mm in diameter and 1.5 mm thick were made from each material using a Perspex mould. The specimens were kept in distilled water at 37°C during the test period. The optical density/mm (inverse of translucency) of each material was measured using a special photometric set up after preparation and after one week, six months, and one year. Means and standard deviations were calculated and subjected to Two-way ANOVA, One- way ANOVA and Scheffe tests.
Results:
The results indicated that all of the materials, except Dyract, showed an increase of translucency over the test period. After one year, the conventional GIC was the least translucent material.
Conclusion:
The translucency of the resin-modified GICs and Dyract was equivalent to that of the composite resins Tetric and Z 100.
