Effect of Photobiomodulation Therapy With an 810-nm Diode Laser on Pain Perception Associated With Dental Injections in Children: A Double-Blind Randomized Controlled Clinical Trial.

Introduction: This study investigated the photobiomodulation effect of an 810-nm diode laser in adjunction with topical anesthesia on pain perception during infiltration anesthesia of primary maxillary molars in children. Methods: This double-blind randomized controlled clinical trial was conducted on 64 children (aged 5-9 years) requiring extraction or stainless steel crown for their primary maxillary molars. The patients were randomly allocated into two groups (n=32) of laser and control. In the laser group, the injection site (buccal and palatal mucosa) was irradiated with an 810-nm laser (200 mW, 5.2 J/cm2) after 20% benzocaine topical anesthetic application, while the control group received a placebo laser following topical anesthesia. The pain intensity experienced by children during needle insertion into the buccal and palatal mucosa was determined using a visual analog scale (VAS) and modified behavioral pain scale (MBPS). Results: According to the results of the VAS and MBPS, no significant difference was detected in pain scores between the laser and control groups neither in the buccal nor in the palatal mucosa (P>0.05). Conclusion: Photobiomodulation therapy with an 810-nm laser with the current setting adjunct to topical anesthesia did not promote significant additional effects on the pain intensity.

Etiological Factors Involved in Molar-Incisor Hypomineralization in 7 to 12-Year-Old Children in Tehran.

Objectives: Molar-incisor hypomineralization (MIH) lesions are common in children. The prevalence of MIH is variable in different communities. However, information regarding the prevalence of MIH in the Iranian population is limited. This study sought to assess the prevalence and etiological factors of MIH in 7-12-year-old children in Tehran. Materials and Methods: This descriptive, cross-sectional study evaluated 1028 elementary students between 7-12 years, selected from different districts of Tehran in 2017. The frequency of MIH in the maxillary and mandibular molars and incisors was determined by clinical examination. In order to assess the role of different factors in the development of MIH, a questionnaire was filled out by the mothers regarding problems during their pregnancy, medical history of children, and age of occurrence of systemic conditions (if any). The effect of different factors on the development of MIH was analyzed by the logistic regression test. Results: The prevalence of MIH was found to be 25.6%. The delivery condition of the mother (P<0.001), history of urinary tract infection (P<0.011), history of chickenpox (P<0.018), and frequent use of amoxicillin during childhood (P<0.041) significantly affected the occurrence of MIH. The most commonly involved teeth were the mandibular left first molars. Conclusion: The prevalence of MIH in our study population was within the range reported in the literature. Considering the relatively high prevalence of MIH in 7-12-year-old children, pediatric dentists should pay special attention to treatment of MIH.

Hereditary Autonomic Neuropathy of the Oral Cavity and its Management.

Hereditary sensory and autonomic neuropathies (HSAN) are rare genetic disorders that often manifest during childhood in the form of absence of pain sensation or self-mutilation. Patients often present significant oral self-mutilation manifestations, and biting of the lips, tongue, and cheeks have been frequently reported. This case report describes a case of hereditary sensory and autonomic neuropathy with oral and cutaneous ulcers. Our patient was a 14-month-old girl with the chief complaint of a tongue ulcer, as stated by her parents, who were referred to our private dental clinic. Clinical examination revealed severe ulcers due to biting (Riga-Fede disease) on the ventral surface of the tongue and superficial ulcers on the dorsal surface of the tongue caused by the anterior maxillary teeth, along with some sores on fingers. The parents were healthy, with no congenital disease or familial history of a similar condition. The electrodiagnostic test revealed the absence of sensory nerve action potential response. However, the electromyographic findings and the compound muscle action potential of the tibial and ulnar nerves were normal. Oral ulcers such as trauma to the lips and tongue, and self-mutilation trauma to the fingers can be used for early detection of Hereditary sensory and autonomic neuropathies. A multidisciplinary approach involving a professional dental team and a regular treatment protocol are imperative to prevent complications of Hereditary sensory and autonomic neuropathies.

Effect of an Educational Pamphlet on Knowledge and Performance of Fitness Trainers about Traumatic Dental Injuries.

Objectives : Traumatic dental injuries (TDIs) commonly occur in sport clubs. The knowledge and performance of fitness trainers play an important role in management of such injuries. This study sought to assess the effect of an educational pamphlet on knowledge level and performance of fitness trainers about TDIs in Tehran in 2018. Materials and Methods: In this interventional study, a pamphlet was designed to enhance the knowledge level of fitness trainers. Ninety-five fitness trainers were randomly divided into two groups of intervention and control (n=49 in the control group and n=46 in the interventional group), and were requested to fill out a valid and reliable researcher-designed questionnaire about TDIs before and 1 month after pamphlet distribution. The questionnaire consisted of three domains of demographic information, knowledge questions, and performance questions. The results were analyzed using SPSS 25 via the Chi-square test and repeated measures ANOVA considering the intervention as the between-subject factor. Results: The knowledge score of fitness trainers about TDIs was not adequately high in the intervention or the control group before the intervention. After the intervention, the performance of participants improved in both groups. This increase was significantly greater in the intervention group (P=0.035). There was no significant difference between the two groups in the knowledge domain (P=0.185). Conclusion: Educational pamphlets can effectively enhance the knowledge level of fitness trainers about TDIs. However, the magnitude of this effect was not significant in our study. Future studies are recommended to compare the efficacy of educational pamphlets with other educational tools.

Effect of photodynamic therapy on microleakage of class V composite restorations in primary teeth.

BACKGROUND: Photodynamic therapy (PDT) is a treatment by which, light sensitive chemicals are activated at a specific wavelength, generating reactive oxygen species which can be antimicrobial and assist in disinfection. However, the oxygen radicals may interfere with the bonding process. The purpose of this study was to assess the effect of PDT with different photosensitizers on microleakage of composite restorations. METHODS: Seventhy-two primary teeth with sound labial/buccal and lingual surfaces were collected for this study. The teeth were randomly divided into four groups of control, PDT with indocyanine green, PDT with methylene blue, and PDT with toluidine blue. Next, the cavities were restored with composite resin. The specimens were stained with 0.5 % Fuchsine and sectioned. The specimens were observed under a microscope to determine the microleakage score. The microleakage was compared between the groups and between the occlusal and cervical walls in each group. Data were analyzed using SPSS version 25. RESULTS: According to the kruskal-wallis test, no significant difference was observed in microleakage between the groups in the occlusal wall (p = 0.859). However, there was a significant difference in the cervical wall between the control and toluidine blue (p = 0.019), and the control and methylene blue (p = 0.008) groups. The Wilcoxon test showed a significant difference in microleakage (p < 0.05) between the occlusal and cervical walls within each group. CONCLUSIONS: PDT may be used in cavities with enamel margins to decrease the microbial load and prevent secondary caries. PDT is not recommended for cavities with cementum margins. Alternatively, it can be performed with indocyanine green as photosensitizer in such cases.

Effect of Dentin Pretreatment with Chlorhexidine on Push-Out Bond Strength of Composite Restorations in Severely Damaged Primary Anterior Teeth.

OBJECTIVES: Achieving durable restorations with adequate strength in severely damaged primary anterior teeth in children is a priority. The aim of this study was to investigate the effect of dentin pretreatment with chlorhexidine on push-out bond strength of composite restorations. MATERIALS AND METHODS: In this in vitro experimental study, 56 extracted primary anterior teeth were randomly divided into 4 groups: (1) saline and total-etch bonding agent, (2) chlorhexidine and total-etch bonding agent, (3) saline and self-etch bonding agent, and (4) chlorhexidine and self-etch bonding agent. After the application of bonding agents, the post space was filled with Z250 composite resin. Following thermocycling of the samples, the push-out test was performed using a universal testing machine, and the results were analyzed with two-way ANOVA. RESULTS: The mean push-out bond strength values in groups 1 to 4 were 5.7, 8.39, 5.35, and 7 MPa, respectively. Chlorhexidine groups had significant differences with saline groups in bond strength (P<0.05) but there was no statistically significant difference between the self-etch and total-etch bonding agents in the groups (P>0.05). CONCLUSION: Both types of bonding agents (self-etch and total-etch) exhibited favorable results in radicular dentin of primary anterior teeth; however, pre-treatment with chlorhexidine increased the push-out bond strength of composite restorations in primary anterior teeth.

Assessment of photobiomodulation therapy by an 8l0-nm diode laser on the reversal of soft tissue local anesthesia in pediatric dentistry: a preliminary randomized clinical trial.

During the injection of local anesthesia in pediatric dental procedures, from the injection time until the elimination of tissue anesthesia, inevitable problems were reported. According to the encouraging results of previous studies addressing the positive effects of laser therapy on increasing the microcirculation, we aimed to investigate the clinical effect of photobiomodulation therapy on the reversal of soft tissue anesthesia in children. Using a split-mouth design, 34 children aged 4 to 8 years old, candidate for receiving local infiltration injection at both right and left side in mandible, were enrolled in the study. The mandibular right and left quadrants were randomly assigned to groups of laser or sham laser: in laser side, patients received 810-nm laser irradiation, and in the sham laser group, the patients had the laser in off mode at 45 min after injection with an interval of 7-10 days between two sessions of each quadrant treatments. The degree of anesthesia was evaluated using the palpation technique alternately every 15 min. Data were analyzed using paired sample t test and multiple linear regression test. The mean duration of anesthesia expressed in minutes was equal to 145.15 ± 23.27 and 188.82 ± 12.31 for the laser group and sham laser group, respectively. There was a significant difference in duration of anesthesia between two groups (P < 0.001). Considering the results and limitations of the present study, photobiomodulation therapy by 810-nm diode laser can be proposed as a non-invasive method in order to reduce the duration of anesthesia in pediatric patients.

Comparative evaluation of the effects of different methods of post space preparation in primary anterior teeth on the fracture resistance of tooth restorations.

Background. Severely damaged teeth do not have adequate structure to support the composite crown; therefore, use of the canal space has been suggested to increase retention. Furthermore, the effect of post space irrigation protocols on the fracture resistance of the primary anterior teeth has not definitely been studied in postoperative modalities. This study compared the fracture resistance of restorations of primary anterior teeth following irrigation of the post space with sodium hypochlorite and chlorhexidine with and without application of burs. Methods. Ninety-four extracted primary anterior teeth were selected. Root canal treatments were carried out, 4 mm of the post space was left empty and 1 mm was regarded as a bed. The post space was prepared with and without a bur and the irrigation procedures were carried out with 0.2% chlorhexidine and 2.5% sodium hypochlorite solutions. Composite posts were inserted into the canals and the crowns were restored. Following composite etching and light-curing, the fracture resistance of the restored teeth was determined by a universal testing machine. Results. In the sodium hypochlorite group, fracture resistance of the teeth was 376.8±107.29 N and 475.5±186.89 N without and with bur preparation, respectively. For chlorhexidine protocol, the values were 370.88±175.46 N and 430.85±178.22 N without and with bur preparation, respectively. The effect of irrigating material was not significant; however, the bur and irrigating preparation significantly increased the fracture resistance of the restored teeth (P=0.02). Conclusion. Post space irrigation with 0.2% chlorhexidine or 2.5% sodium hypochlorite did not significantly affect the fracture resistance of primary anterior teeth in the post treatment modality.

Comparison of Microleakage of Pedo Jacket Crowns and Stainless Steel Crowns Cemented with Different Cements.

OBJECTIVES: This study aimed to assess the microleakage of Pedo Jacket crowns compared to stainless steel crowns (SSCs) cemented with different luting cements. MATERIALS AND METHODS: In this in-vitro experimental study, 80 primary molars were randomly divided into four groups of 20 each. Groups 1 and 2 were subjected to standard tooth preparation for SSC. Crowns in group 1 were cemented with glass ionomer (GI), and crowns in group 2 were cemented with a resin-modified glass ionomer (RMGI) cement. In groups 3 and 4, minimal tooth preparation was performed for Pedo Jacket crowns, and the crowns were cemented with RMGI and Panavia resin cement, respectively. Microleakage was measured at mesial and distal surfaces in micrometers (µm), and the mean value for each tooth was calculated. Oneway analysis of variance (ANOVA) was applied to compare the microleakage of the four groups. RESULTS: Group 3 (Pedo Jacket cemented with RMGI) showed the highest microleakage (1523.83±250.32 µm) with significant differences with the remaining three groups (P<0.001). Microleakage in group 4 (Pedo Jacket cemented with Panavia) was significantly lower than that in the other three groups (301.25±219.53 µm, P<0.001). Groups 1 (SSCs cemented with GI) and 2 (SSCs cemented with RMGI) were not significantly different in terms of microleakage (P=0.49) although group 1 showed slightly higher microleakage than group 2 (598.43±260.85 µm versus 500.25±124.74 µm). CONCLUSION: Pedo Jacket crowns can serve as an acceptable esthetic alternative to SSCs if cemented with resin cements.

Comparison of Canine Overlap in Pediatric Patients Requiring Stainless Steel Crown Placement under General Anesthesia before and after the Procedure.

OBJECTIVES: Despite the increasing popularity of pediatric dental treatments under general anesthesia, information is scarce regarding occlusal changes in patients receiving stainless steel crowns (SSCs) under general anesthesia. This study sought to compare canine overlap before and after general anesthesia in children receiving SSCs. In case of a change, the possibility of returning to the preoperative state and the time required for this process were also evaluated. MATERIALS AND METHODS: This interventional, before-and-after study was performed on 60 children between 2 to 7 years of age requiring dental treatment under general anesthesia. The contact point of the most prominent area of the maxillary primary canine and mandibular primary canine was marked before and immediately after general anesthesia and at one and two weeks postoperatively. The change in canine overlap was analyzed using repeated measures analysis of variance (ANOVA) and linear regression test. RESULTS: Canine overlap significantly decreased immediately after general anesthesia (P<0.05). The mean bite opening was 0.51±0.22 mm at the site of the right canine and 0.50±0.185 mm at the site of the left canine. These values returned to their normal preoperative state after one week (P<0.05). Repeated measures ANOVA showed significant differences in this respect between the time points (P=0.002). CONCLUSION: The occlusion and vertical dimension of pediatric patients may change following dental treatment under general anesthesia; the magnitude of change in canine overlap may vary depending on the class of occlusion and number of SSCs placed. These changes are temporary and often resolve within a week.

Effect of Precuring and Postcuring of Total-Etch and Self-Etch Bonding Agents on the Microleakage of Fissure Sealants.

OBJECTIVES: Considering the importance of timesaving in pediatric dentistry, if the efficacy is achieved along with shorter working time and less technical sensitivity, the behavior management of young patients can be anticipated. This study aimed to compare the effect of precuring and postcuring of total-etch and self-etch bonding agents on the microleakage of sealants. MATERIALS AND METHODS: This study was conducted on forty impacted third molars, which were surgically extracted. The samples were divided into five groups: 1. Control (etching and sealant), 2. Precured fifth-generation bonding agent (Adper Single Bond 2) and fissure sealant, 3. Postcured fifth-generation bonding agent (Adper Single Bond 2) and fissure sealant, 4. Precured seventh-generation bonding agent (Single Bond Universal) and fissure sealant, and 5. Postcured seventh-generation bonding agent (Single Bond Universal) and fissure sealant. All specimens were thermocycled (×1000), immersed in 0.5% basic fuchsine solution for 24 hours, sectioned, digitally photographed, and measured using the LAS EZ program. The data were analyzed using Kruskal-Wallis and Dunn's tests. RESULTS: Leakage in the control group and the third group was significantly lower than that in other groups. In pairwise comparisons, a significant difference was found between the control group and the fifth group and between the third group and the fifth group. CONCLUSION: The conventional method of sealant placement showed superior results in comparison with the use of an intermediate layer of the bonding agent.

Thermal Changes in Root Surface of Primary Teeth During Root Canal Treatment With Diode Lasers: An In Vitro Study.

Introduction: Increased temperature due to the application of laser during root canal disinfection may damage periodontium, alveolar bone, and permanent dental germ. The aim of this study was to evaluate the temperature increase of the external surface of primary roots due to the application of 810 nm and 980 nm diode lasers. Methods: A total of 58 extracted human primary teeth were prepared and randomly divided into two groups: (a) 810 nm diode laser and (b) 980 nm diode laser. Then, each group was divided into 4 subgroups based on the location of the temperature measurement, including subgroup 1: external root surface of primary anterior roots (A); subgroup 2: external root surface of posterior teeth at inter-root space (IS); subgroup 3: external root surface of posterior teeth at outer-root space (OS) and subgroup 4: external surface of furcation area of posterior teeth (F). Results: The mean temperature rise in group a (7.02±2.95ºC) was less than that of group b (10.62±4.59ºC) (P<0.001). Also, a significant difference was found between the laser groups in terms of the mean temperature rise of the external root surface at IS, OS and F, with higher temperature increase occurring in all points in laser b. The comparison of irradiation points in each laser showed a higher mean temperature rise for IS than OS, but this difference was only significant in group b (P<0.001). Conclusion: Within the studied parameters, 810 nm and 980 nm diode lasers should be used cautiously in primary root canals because of their temperature rise during their application.

Effects of Laser and Fluoride on the Prevention of Enamel Demineralization: An In Vitro Study.

Introduction: Investigations have demonstrated that fluoride is an essential element in preventive dentistry. However, there are still controversies about the preventive effects of various kinds of laser. The aim of this study was to examine the effect of diode laser irradiation (810 nm) with or without fluoride therapy in the prevention of deciduous enamel demineralization. Methods: Sixty deciduous molar crowns were randomly assigned to 6 groups: C: received no treatment; F: fluoride varnish application; 2L: 2 times diode laser irradiation; 4L: 4 times diode laser irradiation; F2L: 2 times laser irradiation over fluoride varnish; F4L: 4 times laser irradiation over fluoride varnish. Teeth in all groups were subjected to a pH-cycling process to produce artificial caries-like lesions. Results: The analysis of variance (ANOVA) of microhardness values indicated a significant great effect for laser, fluoride, and the interaction of laser- fluoride on reducing the final microhardness value (P<0.001). However, the 2L group was an exception. Despite the 4L group, it did not show a significant prevention of enamel microhardness loss (P=0.125). These 2 groups exhibited different effects in the absence of fluoride (P 2L-4L=0.05) while in the presence of the fluoride varnish, no statistically significant difference was observed between them (P F2L-F4L=0.257). Moreover, no statistically significant difference was observed between the laser-fluoride combination group and the fluoride group (P F2L-F=0.133, P F4L-F=0.926). Conclusion: Our results suggest that fluoride varnish, diode laser, and their combination decrease the loss of the enamel microhardness value and potentially prevent deciduous enamel demineralization. However, the combination of laser and fluoride was not more effective than fluoride.

Push-out bond strength of different intracanal posts in the anterior primary teeth according to root canal filling materials.

BACKGROUND: This study was carried out to evaluate the effect of root canal filling on the bond strength of three intracanal posts in the primary incisors. MATERIALS AND METHODS: Sixty primary incisors were prepared and then divided into two groups (n = 30). The first group canals obturated with zinc oxide eugenol (ZOE) and Group 2 canals obturated with Metapex. Further, the two group categories were divided into three subgroups (n = 10): (1) short composite post (SCP), (2) glass fiber posts (GFPs) cemented with flowable composite, and (3) GFP with glass ionomer cement (GFP + GIC). The push-out test was performed with a universal testing machine. The results were statistically analyzed with two-way analysis of variance.(α = 0.05). RESULTS: The mean bond strength of the first group obturated with ZOE was lower than that of the second group obturated with Metapex (P = 0.046). Moreover, from a statistical point of view, in all three subgroups, the correlation of mean push-out bond strength between SCP and GFP coated with flowable composite was not substantial at P = 0.97. However, the mean bond strength of SCP was in fact significantly greater than that of the GFP coated with GIC since P = 0.034. CONCLUSION: Using ZOE resulted in the significant reduction of the mean bond strength of the intracanal posts when utilized in the primary anterior teeth. Likewise, SCP and GFP coated with flowable composite showed higher push-out bond strengths for restoring primary anterior teeth.

Coronal Sealing Capacity of Temporary Restorative Materials in Pediatric Dentistry: A Comparative Study.

AIMS: The aim of this in vitro study is to compare the coronal microleakage of three common temporary restorative materials, namely Coltosol, Compoglass, and Zonalin, used in pediatric dentistry after endodontic treatment at different time intervals (1 week, 1, and 2 months) using dye penetration. MATERIALS AND METHODS: Access cavities were prepared in 72 intact extracted premolar teeth. The samples were divided into three groups (n = 24) and filled with Coltosol, Compoglass, or Zonalin. After thermal cycling for 500 cycles (5-55°C), the teeth were immersed in 1% methylene blue dye at 37°C for 1 week (n = 8), 1 month (n = 8), and 2 months (n = 8). The samples were sectioned buccolingually, and the linear depth of dye penetration was measured using a stereomicroscope at 16 × magnification. The data were analyzed using Kruskal-Wallis test. RESULTS: There were no significant differences in the micro-leakage values of Coltosol and Zonalin or Zonalin and Com-poglass groups at 1 week (p > 0.05) or 1 month (p > 0.05) intervals, but a significant difference was noted between Coltosol and Compoglass groups (p < 0.01); Coltosol provided a more favorable coronal seal. No significant difference was found among the experimental groups at the 2-month interval (p > 0.05). CONCLUSION: At 1 week or 1 month of use, Coltosol showed better coronal seal. At 2 months, there was no significant difference apparent between the groups. A longer time lapse was associated with an increased likelihood of microleakage. HOW TO CITE THIS ARTICLE: Milani S, Seraj B, Heidari A, Mirdamadi A, Shahrabi M. Coronal Sealing Capacity of Temporary Restorative Materials in Pediatric Dentistry: A Comparative Study. Int J Clin Pediatr Dent 2017;10(2):115-118.

Effect of antimicrobial photodynamic therapy on the counts of salivary Streptococcus mutans in children with severe early childhood caries.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) is a novel technique for reduction of pathogenic microorganisms in dentistry. The aim of this study was to evaluate the effects of aPDT on Streptococcus mutans reduction in children with severe early childhood caries. METHODS: Twenty-two children with severe early childhood caries aged 3-6 years were treated with toluoidine blue O (TBO) for 1min and irradiated by a Light Emitting Diode (LED; FotoSan, CMS Dental, Denmark) with the exposure time of 150s. Saliva samples were collected at baseline, 1h and 7 days after treatment. S. mutans counts were determined using the Dentocult SM Strip mutans. RESULTS: The counts of S. mutans in saliva decreased significantly after 1h (P<0.001). However, the difference in reduction of S. mutans counts in saliva was not significant between the baseline and 7 days after treatment (P>0.05). CONCLUSION: aPDT seems to be efficient to reduce salivary S. mutans immediately after treatment in children with severe early childhood caries. However, further research is needed to evaluate different doses and frequency of irradiation in combination with restoring carious teeth to find more durable results.

Relationship Between Different Types and Forms of Anti-Asthmatic Medications and Dental Caries in Three to 12 Year Olds.

OBJECTIVES: Asthma is a common chronic disease. Asthma and anti-asthmatic medications have been suggested as risk factors for increased susceptibility to caries. This study was conducted to evaluate the effects of different types and forms of antihistaminic medications and the duration of drug consumption on the severity of dental caries in asthmatic children. MATERIALS AND METHODS: This cross-sectional study was conducted in Asthma and Allergy Department of Children's Medical Center in Tehran, Iran. Eighty-five children between three to 12 years who had been diagnosed with asthma, by means of taking medical history, clinical examination and spirometry were chosen by non-simple random sampling. The participants and their parents were interviewed. Oral examination was performed by a qualified dentist. The data were collected by use of questionnaires and analyzed by the stepwise multivariate linear regression analysis, using SPSS version 16. P<0.05 was considered statistically significant. RESULTS: There was a significant correlation between the number of cetirizine and ketotifen tablets taken and decayed/missing/filled (dmf/DMF) teeth score (P=0.006). There were no correlations between the number of consumed sprays and dmf/DMF score (P=0.923), the duration of drug therapy (P=0.907) or the type of medication taken including ß2 agonists, antihistamines, steroids or a combination of them (P=0.907). CONCLUSIONS: The present study showed that the tablet form of medications significantly increased the severity of dental caries even in presence of confounders (sex, age, duration of disease, tooth brushing, sugar consumption, fluoride therapy, mouth dryness).

Fracture resistance of three different posts in restoration of severely damaged primary anterior teeth: An in vitro study.

BACKGROUND: Restoration of anterior primary teeth with severe caries lesion is a big challenge. The aim of this study was to compare the fracture resistance of three types of post, including composite resin, customized quartz fiber and prefabricated glass fiber in restoration of severely damaged primary anterior teeth. MATERIALS AND METHODS: Sixty extracted human primary maxillary incisors were randomly divided into three groups: Group 1: Customized quartz fiber post, Group 2: Composite post and Group 3: Prefabricated glass fiber post. Due to the effect of bonded area on the fracture resistance, the bonded surface of each sample was measured 1 mm above cementoenamel junction. An increasing force was subjected with a crosshead speed of 0.5 mm/min by a universal testing machine until fracture occurred, and the failure mode was assessed afterwards. Data were analyzed using One-way analysis of variance and Kruskal-Wallis tests. The level of significance was considered at P < 0.05. RESULTS: The mean fracture resistance values of three groups were 343.28 N, 278.70 N and 284.76 N, respectively. Although customized quartz fiber post showed the greatest fracture resistance, statistical analysis revealed no significant difference between groups (P = 0.21). The mean fracture strength values of three groups were 12.82 N/mm(-2), 11.93 N/mm(-2) and 11.31 N/mm(-2), respectively; however, the differences were not statistically significant (P = 0.72). Favorable failure mode was more frequent in all groups (P = 0.12). CONCLUSION: Within the limitations of this study, it can be concluded that all three types of studied posts can be successfully used to restore badly destructed primary anterior teeth.

The effect of low-level laser therapy (810 nm) on root development of immature permanent teeth in dogs.

Traumatic injuries and dental caries can be a big challenge to immature teeth. In these cases, the main purpose of treatment is to maintain the pulp vitality. The purpose of this study was to investigate the effect of low-level laser therapy on accelerating the rate of dentinogenesis in pulpotomy of immature permanent teeth (apexogenesis). Three dogs, 4-6 months old, were used in this study. One jaw in each dog was randomly assigned to laser irradiation group. All selected teeth were pulpotomized with mineral trioxide aggregate (MTA) and restored with amalgam. In the laser group, the Ga-Al-As laser (810 nm, 0.3 W, 4 J/cm(2), 9 s) was used on buccal and lingual gingiva of each tooth in 48 h intervals for 2 weeks. In order to observe the newly formed dentine, tetracycline was injected on the 1st, 3rd, 7th, and 14th day after the operation. Then, ground sections of teeth were observed under a fluorescence microscope. The data was analyzed with Generalized Estimating Equations (GEE) test. The mean distance between the lines of tetracycline formed on the 1st and 14th day was significantly higher in the laser group (P = 0.005). Within the limitation of this study, irradiation of Ga-Al-As laser (810 nm) can accelerate the rate of dentinogenesis in apexogenesis of immature permanent teeth with MTA in dogs.

Fracture resistance of cementum-extended composite fillings in severely damaged deciduous incisors: An in vitro study.

OBJECTIVE: The aim of this study was to comparatively assess the fracture resistance of the cementum-extended and conventional composite fillings with or without intracanal composite posts in severely damaged deciduous incisors. MATERIALS AND METHODS: This in vitro study was performed on 60 extracted deciduous maxillary incisors that were randomly divided into four groups: Group 1: Composite filling (CF); Group 2: Composite filling with composite posts (CF + CP); Group 3: Composite filling extended 0.5 mm to cementum (ceCF); Group 4: Composite filling extended 0.5 mm to cementum with composite posts (ceCF + CP). The fracture resistance was assessed by exerting a progressively increasing load with a cross-head speed of 0.5 mm/min in a Universal Testing Machine. STATISTICAL ANALYSIS: Data were analyzed by SPSS-18 using one-way analysis of variance at α < 0.05. RESULTS: The mean fracture resistance (MFR) values of the experimental groups were 410.57 ± 139.44 N, 564.44 ± 92.63 N, 507.5 ± 76.37 N and 601.08 ± 96.04 N. A significant difference was found between the MFR of Groups 1 and 2, Groups 1 and 4 and Groups 3 and 4 (P < 0.05). CONCLUSION: A superior outcome was achieved by intracanal composite posts in both conventional and cementum-extended composite fillings.