Journal of Dental School
Year:2011 | Volume:28 | Issue:4 (86)|Papers Count:9

Background and Aim: Chemotherapeutic agents are adjunctive substances for treatment of periodontitis through modulation of host response. Sodium alendronate is one of the medicaments which are used for this purpose. Since alkaline phosphates (ALP) level is an indicator for evaluation of bone metabolism changes, in this study the effect of sodium alendronate on periodontitis is investigated by measuring gingival crevicular fluid alkaline phosphates (GCF ALP) levels.Materials and Methods: In this double-blind experimental study, 24 patients (12 males and 12 females between the agen of 35 to 50 years) with moderate chronic periodontitis have been evaluated. All patients received scaling and root planning. Sodium alendronate and placebo capsules were used weekly in a period of six months for case and control groups respectively samples were collected in first visit, 3 months, and 6 month later and analyzed with spectrophotometry. Periodontal assessments were probing pocket depth, gingival index (loe and silness) and plaque index (silness and loe). Data were analyzed by t-test, repeated measurement paired t-test.Results: Mean changes of GCF ALP optical absorbtion were significant in case group through the period of 6 months, and in control group through the period of 3 months, however after 6 months in control group there is no significant changes in comparison with base line evaluations. During the study GCF ALP changes between two group were not significant statically. Mean changes of plaque index and gingival index were statically significant in both groups through 6 months period. Plaque index variations were significantly different between two groups. But duration of gingival index changes between 2 groups was insignificant.Conclusion: The use of sodium alendronate for 6 months improves periodontal parameters and decrease GCF ALP level, but these results are not so significant during this period of time.

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 material and plants, in this in vitro study effect of hydroalcoholic extract of Salvia officinalis and Menta longifolia 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 Menta longifolia with maceration method. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated with broth macrodilution method. Results have been analyzed with Mann-Whitney test.Results: Minimum inhibitory concentration for Salvia officinalis and Menta longifolia for streptococcus mutans were respectively 6.25 and 12.5 mg/ml, for Lactobacillus rhamnosus 1.56 and 3.12 mg/ml and for Actinomyces viscosus 12.5 and 100 mg/ml.Conclusion: Both extracts had growth inhibitory effect on all three bacteria. Saliva officinalis had greater effect on inhibition of growth of all three bacteria (p<0.05). Both extracts had bactericidal effect in the range of studied concentrations.

Background and Aim: Several different graft materials, e.g. autologous, allografts, alloplasts or xenografts have been used to preserve or reconstruct the ridge anatomy. The purpose of this study was to investigate histologically and histomorphometrically experimental defects that grafted with Bio-Gen and Bio-oss and influence of local delivery of Alendronate with graft materials on bone formation.Materials and Methods: This experimental study did in 5 dog’s tibia, 7 round intrabony defects, 6 mm in diameter and approximately 4 mm in depth were made with trephine bur, each defect in each tibia filled randomly with following groups: 1) Bio-Gen (Bio-teck)+BCG membrane, 2) BBM (Bio-Oss)+Bio-gide membrane, 3) Bio-Gen+alendronate+BCG membrane, 4) Bio-oss+alendronate+Bio-gide membrane, 5) BCG membrane, 6) Bio-gide membrane, 7) Control (empty). Animals developed euthanized after 3 months. Immediately after euthanasia the tibia bones were dissected out and the proximal part of the tibias containing the defects were removed in blocks and prepared for Histologic and Histomorphometric evaluation. The data were analyzed using the ANOVA and Tukey procedures. P-values were less than 0.05.Results: Newly formed bone was well evident in all of the defects inflammatory cells were less than 10% in all of them. The mean percentage of new bone in these 4 groups (with grafted materials) was higher than the other ones (with membrane and without grafted materials) and control groups (p<0.05). There is no statistical different between Bio-Oss and Bio-Gen groups (with or without alendronate) in vital bone percentages.Conclusion: Application of single dose alendronate combination with Bio-oss or Bio-Gen granules doesn’t improves bone formation. Bio-Gen granules are considered an osteoconductive graft material suitable for regeneration of bone.

Background and Aim: The desirable mechanical properties of nickel-titanium alloy wires have prompted many clinicians to recycle these wires. The purpose of this study was to investigate the changes in mechanical properties of nickel-titanium alloy wires after recycling by electromechanical treatment.Materials and Methods: In this experimental study, round 0.018 inch nickel-titanium wires (American Orthodontics trademark) were used. For purpose of determining the behavior of samples in mouth, the transformation temperatures of alloy were carried by electrical resistance test. The types of nickel-titanium wires were separated into three groups: 1- as received condition (control wires), 2- treated by low electrical current, 3- treated by high electrical current. Mechanical properties changes were observed by tensile testing. One-way analysis of variance and Tukey HSD (SPSS statistical package) was used for purpose of comparison. Results: The results demonstrated significantly greater remained strains after recycling, but plateau stresses and elastic strain energies of the wires were decreased compared with the control wires.Conclusion: Super elastic property of electromechanical treated nickel-titanium wires is decreased following electromechanical treatments.

Background and Aim: Marginal integrity in all ceramic restorations is one of the important elements of the success rate. According to the importance of design preparation in the marginal integrity, in this in-vitro study, decided to compare the marginal integrity between 2 different types of the marginal preparation: shoulder and classic chamfer in IPS e.max press restoration.Methods and Material: This experimental research has been done in vitro with the single blind technique. One standard die with 7 mm height, 5mm diameter was prepared by the milling machine. the preparation design consists half shoulder 90 degree and in the other half classic chamfer, with 1 mm depth in both of them and 10 degree tapering and then crowns were made of IPS e.max press and after cementation, were ground at the buccolingually direction. Then they were coated by gold and observed under SEM. The data assessed by T-Test.Results: A difference between 2 types of marginal preparation was significant (p<0.05). Marginal gap in shoulder preparation was 15.45±0.79 and in classic chamfer site was 13.78±0.52.Conclusion: The marginal fitness in the classic chamfer preparation was better than shoulder preparation in all ceramic restorations.

Background and Aim: Due to the deeper penetration of bacteria like Enterococcus faecalis into dentinal tubules in pulp diseases, different tapering in root canal therapies leads in different dentinal removal from root canal wall. Then, root canals with higher tapering will contain lower microbial microbial contents. Furthermore, together with higher prevalence of root fractures in teeth with more tapering, the aim of this study is comparing the effect of different tapering of Hero Rotary files (6% versus 4%) in reduction of Enterococcus faecalis bacteria from the root canal of human extracted teeth.Materials and Methods: Seventy human extracted teeth were divided in two equal experimental (Hero 4%as group 1and Hero 6% as group 2) (n=27) and the control group (n=6).Two extra control group (positive n=5 and negative n=5) took for confirmation the canal reinfection, too. All of the samples prepared by K file No 20 and Gates Gilden No 2 and 3 before sterilization. Then the teeth were autoclaved and were infected with Enterococcus faecalis. The experimental groups were instrumented either with Hero 4% or with Hero 6% files up to #30. Bacteriological samples were taken after instrumentation to determine the level of remaining bacteria.Results: In the group 1 two samples and in the group 2 six samples represented complete reduction of bacteria. There was not statistically significant different between the two groups.Conclusion: Aggressive preparation with an instrumentation technique removing substantial amounts of dentin (Hero 6%) did not reduce the intracanal bacteria more effectively than a more conservative instrumentation technique (Hero 4%) (P>0.05).

Background and Aim: Gonadal hormones have effect on the growth through increasing the osteoblastic activity of bone. They have influence on the calcium metabolism and therefore, are influential on the calcium level of serum and the strength of the bones. The purpose of this study is to examine the effects of gonadal hormones deficiency on the percentage of bone calcium of the tibia in rats.Materials and Methods: In the present experimental study 50 thirty-day-old Wistar rats comprised the sample. 25 male rats were randomly divided into 2 groups: Experimental group, i.e. orchidectomy ORX, (n=15) and control group, sham- operation, (n=10) and also 25 female rats were divided in the same way into 2 groups: Experimental group, i.e. ovariectomy OVX, (n=15) and control group, sham- operation, (n=10). Samples were sacrificed 6 months after the surgery i.e. orchidectomies, ovariectomies, and sham operations. Percentage of bone calcium was determined by atomic absorption spectrophotometry. Serum testosterone, progesterone and estradiol levels were measured by ELISA.Results: Serum testosterone level significantly decreased in the ORX group as compared with the male sham- operated group. In this study estradiol level was not changed in OVX group, but despite the significant decrease in progesterone level (p<0.001), no significant differences in all variables were found between the OVX group and female sham- operated group. In the ORX group, body length and weight, were significantly smaller than in the male sham- operated group. No significant difference in bone calcium percentage was found (Student’s t-test) between control and experimental groups.Conclusion: In conclusion, it seems that the suppression of gonadal hormones secretion in the growth phase cannot decrease calcium percentage of tibia bone in rats.

Background and Aim: Given the high prevalence of dental caries and periodontal diseases and the importance of quality of life in clinical decision making, this study investigated the association between periodontal diseases and dental caries and the presence of condition-specific socio-dental impacts on quality of life attributed to these conditions among Iranian schoolchildren.Materials and Methods: Total of 310 11-14-yr-old students, attending middle schools in Tehran, Iran, were selected through stratified cluster sampling. First, they were interviewed using Child Oral Impacts on Daily Performances (Child-OIDP) index. An oral examination was conducted next and number of decayed teeth, OHI-S and bleeding on probing (BOP) were recorded. Statistical associations were tested using Independent sample t-test, Chi-square and Binary logistic regression tests.Results: Dental caries and poor oral hygiene were significantly more common in boys than in girls (P=0.001 and P=0.000, respectively). About 30.6% and 34.8% of children reported condition- specific socio-dental impacts attributed to periodontal diseases and dental caries, (CSI-periodontal and CSI- caries) respectively. Girls were 1.8 times more likely than boys to report the presence of CSI-periodontal. Brushing the teeth was significantly associated with the presence of CSI-caries and CSI-periodontal (P<0.05). In addition, the relationship between dental caries and the presence of CSI- caries was significant (P<0.05). BOP and OHI-S were not significantly associated with the presence of CSI-periodontal (P>0.05).Conclusion: Dental caries, unlike BOP and OHI-S, was significantly associated with its corresponding CSI on quality of life among Iranian schoolchildren in Tehran. The Child-OIDP index can be used to assess the treatment needs attributed to dental caries in schoolchildren in Tehran.