Effect of low-level diode laser on streptococcus mutans and lactobacillus acidophilus growth: An invitro study.

Introduction: Caries lesions are high prevalent dental infectious. Gram-positive bacteria are the most common pathogenic microorganisms causing caries lesions. Low-Level laser therapy has been shown to have a significant bactericidal effect without causing damage to the oral tissues. This study was designed to evaluate the efficacy of diode laser (980 nm) at different times and doses on Streptococcus (S.) Mutans and (Lactobacillus) L. Acidophilus microorganisms. Methods: This study was performed on two groups of microorganisms, including S. mutans and L. acidophilus, at a concentration of 108 CFU/ml, which exposed to a diode laser source with a central wavelength of 980 nm to investigate three different energies with the following time-exposures (at doses of 5, 10 and 20 J/cm2 with irradiation times of 5, 10 and 20 s). The growth of bacteria (CFU/ml) was calculated. Results: A significant decrease in CFUs/ml of two microorganisms was observed immediately and 24 h after irradiation (p-value < 0.05). The most effective laser radiation for S. mutans immediately and 24 h after exposure was seen at 5 s with 20 J/cm2 and 20 s with 5 J/cm2, respectively. The most effective laser radiation for L. acidophilus was the time of 5 s with 10 J/cm2 both immediately and 24 h after exposure. Conclusion: In the present study, we demonstrated that diode laser (980 nm) has great efficacy in the growth reduction of S. mutans and L. acidophilus at different times and doses.

Comparing success of immediate versus delay loading of implants in fresh sockets: a systematic review and meta-analysis.

BACKGROUND AND AIMS: The replacement of teeth with osseointegrated implants is one of the significant advances in the field of restorative dentistry. The time interval between tooth extraction and the implant can be very short or long. This systematic review and meta-analysis aimed to collect and evaluate articles related to determining the effect of instant loading of dental implants are placed in the fresh socket initial stability on the clinical success of the implant compared to delay loading dental implants. MATERIALS AND METHODS: In this study, all the available articles indexed in leading databases, including PubMed, ISI Web of Science, Embase, PsycINFO, PROSPERO, and Scopus, were searched. The full text of the articles meeting the primary criteria to be included in this research was obtained and appraised. Data of studies were extracted if they were scored as a high or moderate level of evidence. RESULTS: A total of 2258 published articles were found through electronic database searching. After screening the titles and abstracts, and full text of articles, 16 studies met the inclusion criteria and were included in the analysis. The results of this study revealed that regarding the success rate, although there was no significant difference between immediate and delayed of dental implants, immediate procedure showed a lower incidence of bone loss in single implants. CONCLUSION: Based on the results of this study, immediate loading of dental implant, under certain conditions, is a successful treatment process and is effective in reducing treatment time. Thus, immediate loading represents a valid alternative to the traditional delayed loading rehabilitation.

A comparative study on the stress distribution around dental implants in three arch form models for replacing six implants using finite element analysis.

BACKGROUND: Dental implant is a method to replacement of missing teeth. It is important for replacing the missed anterior teeth. In vitro method is a safe method for evaluation of stress distribution. Finite element analysis as an in vitro method evaluated stress distribution around replacement of six maxillary anterior teeth implants in three models of maxillary arch. MATERIALS AND METHODS: In this in vitro study, using ABAQUS software (Simulia Corporation, Vélizy-Villacoublay, France), implant simulation was performed for reconstruction of six maxillary anterior teeth in three models. Two implants were placed on both sides of the canine tooth region (A model); two implants on both sides of the canine tooth region and another on one side of the central incisor region (B model); and two implants on both sides of the canine tooth region and two implants in the central incisor area (C model). All implants evaluated in three arch forms (tapered, ovoid, and square). Data were analyzed by finite analysis software. RESULTS: Von Mises stress by increasing of implant number was reduced. In a comparison of A model in each maxillary arch, the stress created in the cortical and cancellous bones in the square arch was less than ovoid and tapered arches. The stress created in implants and cortical and cancellous bones in C model was less than A and B models. CONCLUSIONS: The C model (four-implant) reduced the stress distribution in cortical and cancellous bones, but this pattern must be evaluated according to arch form and cost benefit of patients.

Salivary Interferon Gamma and Interleukin-4 Levels in Patients Suffering from Oral Lichen Planus.

OBJECTIVE: Oral lichen planus (OLP) is a chronic inflammatory disease. Immunological factor may act as etiological factor. The cellular immune cells such as T cells are impor- tant in pathogenesis. Interferon gamma (IFN-γ) and interleukin 4 (IL-4) are secreted by T-helper 1 (Th1) and Th2, respectively. The aim of this study was to investigate the cor- relation between salivary levels of IFN-γ and IL-4 with OLP. MATERIALS AND METHODS: This case control study included sixty three Iranian OLP patients who were selected from the Department of Oral Medicine of Ahvaz Jundishapur University of Medical Sciences from January to July 2013. An equal number of healthy volunteers were also selected as a control group. The OLP patients were then divided into two follow- ing sub-groups: reticular (n=30) and erythematous/ulcerative (n=33). All patients had no systemic disease and received no medication. IFN-γ and IL-4 levels in whole unstimulated saliva (WUS) were measured using the enzyme-linked immunosorbent assay (ELISA) test. Data analysis was done using t test, ANOVA, least significant difference (LSD) test, and the Kruskal-Wallis test. RESULTS: Reticular OLP patients showed higher salivary IFN-γ (7.74 ± 0.09 pg/ml ) and IL-4 (3.876 ± 0.05 pg/ml) levels compared with the control group, indicating that difference was significant. Salivary IFN-γ/IL-4 ratio significantly increased compared with control group (P=0.042). Salivary IFN-γ and IL-4 levels between sub-groups (re- ticular and erythematous/ulcerative) were not significantly different (2.6 ± 0.06 and 2.3 ± 0.05, respectively, P<0.05). CONCLUSION: Salivary IFN-γ and IL-4 levels were increased in OLP patients. An increase of salivary IFN-γ/IL-4 ratio in OLP patients showed that Th1 might have a dominant role in the OLP pathogenesis.

Investigation of The Association between Salivary Procalcitonin Concentration and Chronic Periodontitis.

OBJECTIVE: Chronic periodontitis is the most common form of periodontal disease. Chang- es in biomarkers seem to be associated with the disease progression. Procalcitonin (PCT) is one of these biomarkers that are altered during infection. This study was established to investigate the relationship between periodontitis as an infectious disease and salivary PCT. MATERIALS AND METHODS: This case-control study was performed on 30 patients with gen- eralized chronic periodontitis and 30 health individuals as control group who were referred to Dental School, Jundishapur University of Ahvaz, Ahvaz, Iran at Feb to Apr 2014. The saliva samples were collected and analyzed by the enzyme-linked immunosorbent assay (ELISA) method. Data analysis was performed using t test with the SPSS (SPSS Inc., Chicago, IL, USA) version 13. RESULTS: In both groups, age and sex distribution values were not significantly differ- ent. The concentrations of salivary PCT in controls and patients ranged from 0.081 pg/ mL to 0.109 pg/mL and from 0.078 pg/mL to 0.114 pg/mL, respectively. The statistically significant differences between the two groups were not observed (P=0.17). CONCLUSION: It seems that salivary PCT concentration is not affected by disease progres- sion. Therefore, PCT is not a valuable marker for the existence of periodontal disease.

Comparison of the Antibacterial Properties of Three Mouthwashes Containing Chlorhexidine Against Oral Microbial Plaques: An in vitro Study.

BACKGROUND: The mouth provides an environment that allows the colonization and growth of a wide variety of microorganisms, especially bacteria. One of the most effective ways to reduce oral microorganisms is using mouthwashes. OBJECTIVES: The aim of this study was to investigate the antibacterial effects of chlorhexidine mouthwashes (manufacture by Livar, Behsa, Boht) on common oral microorganisms. MATERIALS AND METHODS: In this in vitro study, isolated colonies of four bacteria, including Streptococcus mutans, S. sanguinis, S. salivarius and Lactobacillus casei, were prepared for an antimicrobial mouth rinse test. The tube dilution method was used for determining the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). RESULTS: The MICs for Kin gingival, Behsa and Boht mouthwashes were 0.14, 0.48 and 1000 micrograms/mL using the tube method for S. mutans, respectively. The MBCs for the mentioned mouthwashes were 0.23, 1.9 and 2000 micrograms/mL for S. mutans, respectively. The MICs for Kin gingival, Behsa and Boht mouthwashes were 0.073, 0.48 and 250 micrograms/mL using the tube method for S. sanguinis, respectively. The MBCs for the mentioned mouthwashes were 0.14, 1.9 and 1000 micrograms/mL for S. sanguinis, respectively. CONCLUSIONS: The Kin Gingival chlorhexidine mouthwash has a greater effect than Behsa and Boht mouthwashes on oral microorganisms and is recommended to be used for plaque chemical inhibition.

Evaluation of salivary tumor necrosis factor-alpha in patients with the chronic periodontitis: A case-control study.

CONTEXT: Periodontitis is a chronic infectious disease that leads to inflammation of the tissues supporting the teeth, bone loss, attachment loss progressively. In chronic periodontitis for starting the host response and inflammatory reaction, the presence of the infectious agent is necessary. AIMS: One of inflammatory factors is tumor necrosis factor-alpha (TNF-α) that appear to be important in the destruction of periodontal tissues that were examined in this study. MATERIALS AND METHODS: This study was performed in the laboratory and case-control study. The samples of study collected from 30 individuals with chronic periodontitis and 30 healthy controls that matched for age and sex, together. Unstimulated saliva samples were collected from patients and then TNF-α level were measured by enzyme-linked immunosorbent assay and were compared with the control group. STATISTICAL ANALYSIS USED: In this study for statistical analysis, Mann-Whitney was used. RESULTS: There were differences in mean salivary concentrations of TNF-α in controls and patients. The average concentration in the case group was 9.1 (pg/ml) and the control group was 8.7 (pg/ml), but there was no significant difference between case and control groups (P > 0.05). CONCLUSIONS: The results of this analysis showed no significant relationship between two groups TNF-α concentration. This biomarker can not seem to be a good index to evaluate or predict periodontal disease.

A comparison of magnetostrictive and piezoelectric ultrasonic scaling devices: an in vitro study.

PURPOSE: The effects of magnetostrictive and piezoelectric devices on tooth surfaces seem to differ with regard to the root surface roughness they produce. This study aimed to compare the results of scaling using magnetostrictive and piezoelectric devices on extracted teeth. METHODS: Forty-four human extracted teeth were assigned to four study groups (n=11). In two groups (C100 and C200), the teeth were scaled using a magnetostrictive device and two different lateral forces: 100 g and 200 g, respectively. In the other two groups (P100 and P200), the teeth were scaled with a piezoelectric device with 100 g and 200 g of lateral force, respectively. he teeth were scaled and the data on the duration of scaling and the amount of surface were collected and analyzed using the t-test. RESULTS: The mean time needed for instrumentation for the piezoelectric and magnetostrictive devices was 50:54 and 41:10, respectively, but their difference was not statistically significant (P=0.171). For root surface roughness, we only found a statistically significantly poorer result for the C200 group in comparison to the P200 group (P=0.033). CONCLUSIONS: This study revealed that applying a piezoelectric scaler with 200 g of lateral force leaves smoother surfaces than a magnetostrictive device with the same lateral force.