Influence of different power outputs of Er:YAG laser on shear bond strength of a resin composite to feldspathic porcelain

Statement of the Problem: Porcelain may fracture or chip if exposed to any traumas and can be repaired by using a resin composite

Purpose: This study was aimed to evaluate the influences of Er:YAG laser on shear bond strength [SBS] of resin composite to feldspathic porcelain

Materials and Method: Seventy-two porcelain blocks were divided into six groups [n=12]: G1: no treatment [control group]; G2: 9% hydrofluoric acid [HF]; G3-6 were separately irradiated with Er:YAG laser using four energy parameters: 2W, 100mj [G3]; 3W, 150mj [G4]; 4W, 200mj [G5] and 5W, 250mj [G6], respectively; and 20 Hz frequency in long-pulse mode. After silane treatment, a resin composite rod was bonded to each of the porcelain block. The SBS was measured following storage and thermocycling. Data were analyzed by one-way ANOVA, Tamhane and Chi-Square tests

Results: The highest SBS [12.29 +/- 3.04 MPa] was obtained with HF [G2]. The lowest SBS [2.23 +/- 0.60 MPa] was observed in G4, followed by G3 [1.96 +/- 0.76 MPa]. G6 had a significantly higher SBS [8.00 +/- 2.22 MPa] than other laser irradiation groups

Conclusion: Although, Er:YAG laser irradiation at 5W, 250mJ/20 Hz was effective in promoting adhesion of resin composite to feldspathic porcelain compared with the control group, it cannot be used as a safe alternative method to HF acid. Laser irradiation with the evaluated parameters in this study does not promote an effective adhesion on porcelain surface to create adequate bond for clinical use

evaluation of perioperative safety of local anesthesia with lidocaine containing epinephrine in patients with ischemic heart disease

The use of local anesthesia with lidocaine containing epinephrine in patients with cardiac disease is controversial in the literature. The aim of our study was determining the safety of use the local anesthesia contain epinephrine in patients with ischemic heart disease that undergoing reconstructive surgery. Thirty two patients that had known ischemic heart disease and candidate to undergo reconstructive surgery for skin tumor enrolled in this study. All patients continued their medication for cardiac disease till morning of the operation. 10 ml lidocaine 2% containing 1:100,000 epinephrine was injected in patients for local anesthesia. The hemodynamic changes and electrocardiographic variables before injection were compared with them after injection, during surgery and till 6 hours postoperation period. A 12 lead electrocardiogram was recorded in all our cases for detection of myocardial ischemic changes. The mean age, weight and height were 58.2 +/- 10.4, 74.8 +/- 14.4 kg and 164.5 +/- 8 cm respectively. Twelve patients [37.5%] were diagnosed with systemic hypertension and 10 patients with diabetes [31.2%]. The comparison of change of systolic, diastolic and mean blood pressure between baseline, during procedure and after operation defined that our subjects did not have any significant disturbance in blood pressure in perioperative period. The comparison of baseline heart rate with heart rate after injection, during procedure and in postoperation period indicated a significant changes in this variable [P=0.044]. The heart rhythm during the perioperative period also failed to exhibit alterations. The ischemic change was not recorded in our patients before injection compared to after injection. None of our patients have any early complications because of infiltration of local anesthetic containing epinephrine in our patients. The use of 10 ml 2% lidocaine with epinephrine 1:100,000 in patients with cardiac disease represent a safe anesthetic procedure. These patients experienced a more profound anesthesia with hemodynamic stability and without myocardial ischemic changes.

hemodynamic effects of spinal block with low dose of bupivacaine and sufentanil in patients with low myocardial ejection fraction

The aim of this study was to assess the effect of spinal block with low dose of bupivacaine and sufentanil on patients with low cardiac output who underwent lower limb surgery. Fifteen patients who had ejection fraction less than 40% [group 1] were compared with 65 cases with ejection fraction more than 40% [group 2] in our study. Our subjects underwent spinal block with 7.5 mg hyperbaric bupivacaine 0.5% and 5 micro g sufentanil. We recorded early events such as hypotension, bradycardia, vasopressor need and ST segment change in our cases. The average mean arterial pressure decreased 13% [110 mmHg to 95.7 mmHg] in group 1 and 20% [160 mmHg to 128 mmHg] in group 2 [P<0.001]. Hypotension due to spinal anesthesia was observed in none of our subjects in both groups and none of our cases need to vasopressor support. All patients remained alert, and no ST segment changes were observed in two groups. In our study none of subjects complained of pain intraoperatively. The subjects were without complaints during the spinal anesthetic in both groups. Spinal block with low dose local anesthetic and sufentanil was a safe and effective method for lower limb surgery in patients with low ejection fraction

effects of low level 660nm laser irradiation on pain and teeth hypersensitivity after periodontal surgery

Tooth pain and sensitization are the two main causes of discomfort after periodontal flap surgery. Effects of low level laser therapy for reducing pain have already been established; these kinds of lasers have been used for tooth desensitization as well. This controlled blind study sought to compare tooth pain and sensitization after 660nm laser irradiation in a split mouth and also in a control group after periodontal flap surgery. Forty patients were enrolled in this study. In these entire patients periodontal flap surgery was done in the upper anterior segment. In the test group, by tossing of a coin the left or right side was determined for laser irradiation, so central incisor, lateral incisor and canine were irradiated by swiping motion of 660nm laser [AZOR, Russia] 25mW, 4.5 J, and 3 min every other day starting one day after surgery; and in collateral segment a placebo probe was put to blind the patients. In the control group, dressing was used after surgery. One, 3, 5 and 7 days after surgery for both groups visual analog score [VAS] for tooth pain and sensitization were recorded for both sides in each patient. In the laser group, both sides had lower VAS for pain than the control group [P< 0.05] after the first day. There was no statistical difference in the laser group between laser irradiated, or non-irradiated segment and for sensitization between groups. Pain can be reduced after periodontal surgery by using low level 660nm laser therapy. Lower pain in both sides in the laser group may be the result of the spread of mediators and neurotransmitters secreted after laser irradiation, or may be because of scattered radiation in the collateral part

[Antibacterial effects of persica and matrica herbal mouthwashes on common oral microorganisms: an in vitro study]

Herbal mouthwashes have been used to improve oral hygiene through antibacterial activity and dental plaque control. The purpose of this in vitro study was to compare the antibacterial effects of Persica and Matnca herbal mouthwashes with Chlorhexidine 0.2% [CHX]. The disc diffusion method was used to measure inhibition zone of tested mouthwashes on Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus sobrinus, Klebsicila pneumonia. Escherichia coli, Pseudomonas aeruginosa and Eikenella corrodens. The paper discs containing mouthwashes were placed on media cultured with bacteria. Blank discs containing distilled water were used as controls. Three samples of each mouthwash were cultured, three times each. In total, including control discs, 240 cultures were performed. After 18 hours of incubation, inhibition zones were measured in millimeter and compared with one another. Data were processed and analyzed using SPSS-16 soft ware and Kruskal-Wallis and Mann-Whitney U-tests. The CHX 0.2% mouthwash significantly exhibited greater inhibition zone than the Persica and Matrica mouthwashes. Persica could not inhibit bacterial growth, except for Klebsiella pneumonia. Also, there were not any significant differences among three samples of mouthwashes and three cultures of each mouthwash. Based on the results of this study, herbal mouthwashes are less potent than the CHX in inhibiting the growth of tested bacteria. Further in vivolin vitro studies are needed to substantiate present findings

[Microbial contamination of 19 consumable dental materials: an in vitro study]

Increase in the incidence of contagious disease emphasizes the importance of microbial contamination of dental materials. The purpose of this in vitro study was to determine microbial contamination of different consumable dental materials for the presence of viable microorganisms. In this study, 19 consumable dental materials were surveyed for microbial contamination. These materials included: three kinds of gutta percha, paper cones, gingival retraction cords, alginates, wooden wedges, two kinds of prophylaxis pastes, and one kind of dental dressing and zinc oxide powder. From each material, three brands and from each brand three samples were obtained. Solid and liquid specimens were cultured on Tryptic Soy Broth, Thioglycolate and Sabouraud Dextrose Agar and all the cultured media were stained by gram method. Data were analyzed by SPSS-16 software using descriptive and analytical [Fisher's exact and Chi-Square] tests. The level of significance was set at 0.05. Both prophylaxis pastes, one kind of dental dressing and zinc oxide powder, two of alginates, two of wooden wedges and one of retraction cords did not have any bacterial contamination. The most common bacteria in the contaminated materials were anaerobic Gram-positive bacilli [18 cases, 32%], aerobic Gram-positive bacilli [17 cases, 30.4%], aerobic Gram-negative bacilli [14 cases, 25%], aerobic Gram-positive cocci [two cases, 3.6%]. Approximately, 47 percent of tested dental materials did not have any microbial contamination. The bacilli were the most common bacteria in contaminated materials. Although these microbes may not be pathogenic in ordinary conditions, they can represent a risk for immunocompromised patients

Prevalence and bilateral occurrence of first permanent molar caries in 12-year-old students

Dental caries is one of the most prevalent chronic diseases in children and DMFT index is the most important quantitative factor for measuring tooth health. The purpose of the present study was to determine prevalence and bilateral occurrence of first permanent molar caries in 12-year-old Iranian students. This cross-sectional study was carried out on 563 twelve-year-old students [307 boys and 256 girls], randomly selected from private and public schools of Rafsanjan, Iran, in 2006. All students were examined clinically for dental caries using the World Health Organization [WHO] criteria by a specialist on a dental chair in Rafsanjan Dental School. Data was analyzed using chi-square and t-test. The mean DMFT score of first permanent molars was 1.9 +/- 1.6 [1.83 boys, 1.98 girls] and 31.4% [32.9% boys, 29.7% girls] of the students were caries free. There were no significant differences between boys and girls. Decayed [D] component yielded to be 40.9%, missing [M] 0.35% and filled [F] 6.22%. Maxillary and mandibular first permanent molars had 80.8% and 84% bilateral caries occurrence, respectively. There were no significant differences between the caries prevalence of right and left sides. Caries prevalence among 12-year-old students in Rafsanjan, Iran is less than the global standards of WHO and FDI for 2000, but close to the gold standard for 2010. Bilateral caries occurrence in the first permanent molars was concluded to be high in the study population

Association between dental caries and body mass index-for age among 6-11-year-old children in Isfahan in 2007

Childhood obesity has been associated with high refined sugar intake. The relationship between sucrose intake and development of dental caries has been established. The aim of this study was to determine the association between age-specific body mass index [BMI-for-age] and dental caries in children. In this cross-sectional study a total of 1003 children were screened. Weight, height, BMI-for-age and dental caries of 633 [317 boys, 316 girls] 6-11-year-old children were clinically examined for dental caries using the World Health Organization criteria by a dentist on a dental chair. Decayed and filled teeth [DFT/dft] indices were used. BMI-for-age and dental caries were analyzed with multiple linear regression, chi-square, and t-tests using SPSS computer software. The findings showed that 16% of the children had a normal weight, 16.9% were at risk of overweight, and 67.1% were overweight. In the normal weight, at risk of overweight, and overweight groups, the mean +/- SE for DFT were 0.34 +/- 0.08, 1.23 +/- 0.13 and 0.73 +/- 0.05, respectively; and 2.01 +/- 0.19, 2.76 +/- 0.18 and 2.59 +/- 0.13 respectively, for dft. Multiple linear regression showed that there was no statistically significant association between BMI-for-age and DFT [R = 0.06] and dft [R = 0.07] indices. 27.7%, 14% and 37.2% of children with normal weight, at risk of overweight and with overweight were caries free, respectively. There was statistically significant association between BMI-for-age and being caries free [p = 0.0001]. There was no association between BMI-for-age and DFT/dft indices. In addition, a high prevalence of at risk of overweight and overweight was seen among 6-11-year-old children in Isafahan, Iran

In vitro study of fracture strength of resin-bonded glass fiber-reinforced composite anterior fixed partial dentures

Restorative dentistry searches the use of glass fiber-reinforced composite is just now experiencing rapid expansion in dentistry. This study compared of fracture strength a glass fiber-reinforced composite [GFRC] and a fiber-reinforced composite [FRC] as a framework for fabrication of resin-bonded fixed partial dentures [RBFPDs]. Twenty RBFPDs were made with GFRC [EverStick] and FRC [Ribbond]. The specimens were stored for 2 weeks at 37° +/- 1°C in distilled water, thermocycled [5°-55°C, x 2500] and statically loaded to fracture. The hounsfieldtesting machine measured fracture strength of the samples. Metal cone with 1 mm tip income vertically to central of labial surface of pon-tic with speed 1 mm/min. The force in Newtons was recorded at debonding of prothosis from abutment teeth and then SEM. The mean and standard deviation for fracture strength of GFRC RBFPDs were 440 +/- 75 and for FRC RBFPDs were 309 +/- 33. ANOVA showed that fracture strength between two groups were statistically significant [pv =0.000247]. SEM examination revealed that debonding between the GFRC RBFPDs and the tooth and no debonding between the glass bundle and the composite. On the basis of the results of this study, GFRC that can be used in the fabrication of 3-unit anterior FPDs