Stimulatory effect of low-level laser therapy on root development of rat molars: a preliminary study.

Several studies suggest a biomodulatory influence of low-level laser irradiation in the inflammatory and reparative processes of dental tissues. The aim of this study was to investigate the stimulatory effect of 808-nm laser irradiation on root development of rat molars and also to evaluate the histological reaction of pulp and periapical tissues. Twenty-four 30-day-old Wistar male rats were randomly assigned to three-time and five-time laser therapy groups. After initial x-ray, using mammography equipment, laser energy was applied at a wavelength of 808 nm (2 J/cm(2), 100 mW, 20 s) to the midroot area of the lower molars of one side of mouth at repeated intervals of the 48 h. The animals were killed 1 day after the final treatment, and root length development of the experimental samples was compared to contra-lateral non-irradiated molars using mammography. The histological reaction of the pulp and periapical tissue was evaluated under light microscopy. Root development was more advanced in irradiated groups than in the non-irradiated controls (p < 0.001). No significant differences, however, could be found between the root development changes in the three-time and five-time laser therapy groups (p > 0.05). Histological findings showed that the occurrence of secondary cement formation was significantly higher in the irradiation groups compared to the controls (p = 0.003). However, there were no statistically significant differences for the frequencies of pulp hyperemia, periodontal ligament fiber organization, or lamina dura remodeling between the groups (p > 0.05). Under the conditions used in this study, 808-nm low-level laser accelerates the rat molar root development in the presence of favorable histological reactions.

Comparison of neutrophil apoptosis, α-defensins and calprotectin in children with and without severe early childhood caries.

BACKGROUND: The infectious nature of severe early-childhood caries (S-ECC) points to the possible participation of immunologic host responses including neutrophils and their antimicrobial products. OBJECTIVES: The aim of this study was to determine the neutrophil apoptosis, α-defensins (HNP1-3) and calprotectin levels in the saliva of preschool children and the association with S-ECC. METHODS: Oral examinations were performed on 87 children aged 3-5 years and non stimulated whole saliva samples were collected. Thirty of these subjects were considered S-ECC children, 30 with moderate caries (MC) and 27 were caries free (CF). To detect apoptosis, cell staining was done with Annexin-V-Fluos and propidium iodide, and they were analyzed by fluorescent microscopy. The concentration of α-defensins and calprotectin were assessed using ELISA. RESULTS: There were no statistical differences between groups considering the HNP1-3 or calprotectin salivary levels (p=0.06 and p=0.23, respectively). The HNP1-3 and calprotectin levels were negatively correlated and the correlation was significant in MC group (p=0.03). Lower levels of apoptotic neutrophils were obtained from CF subjects as compared with S-ECC children (p=0.03). CONCLUSIONS: Our findings establish that apoptotic mechanisms could be implicated in the immunity responses associated with S-ECC. We cannot yet determine if the level of salivary α-defensins or calprotectin is predictive of S-ECC.

The effect of Er,Cr:YSGG laser and air abrasion on shear bond strength of a fissure sealant to enamel.

PURPOSE: The authors conducted an in vitro study to evaluate the shear bond strength of a fissure sealant to enamel pretreated with erbium,chromium:yttrium, scandium,gallium,garnet (Er,Cr:YSGG) laser or air abrasion followed by acid etching. METHODS: The authors sectioned extracted sound premolars mesiodistally and used the buccal and lingual surfaces for experimental analysis. They divided specimens randomly into three groups of 15 each according to the enamel surface pretreatment methods: group A, 37 percent phosphoric acid; group B, air abrasion followed by acid etching with 37 percent phosphoric acid; group C, irradiation with Er,Cr:YSGG laser followed by acid etching with 37 percent phosphoric acid. After applying a bonding system, the authors bonded cylinders of sealant to the enamel surfaces by using transparent gelatin tubes (0.7 millimeter in diameter and 1 mm in height) and then polymerized them. They stored all specimens in distilled water at 37 degrees C for 24 hours. They tested shear bond strength by using a universal testing machine with a crosshead speed of 0.5 mm per second. The authors analyzed the data by means of one-way analysis of variance and Tukey-Kramer post hoc tests (alpha = .05). RESULTS: The bond strength of group B specimens was statistically higher than those of group A and group C specimens (P < .05). The authors found no statistically significant differences in shear bond strength between surfaces treated with Er,Cr:YSGG laser and those treated with acid etching alone (P > .05). CONCLUSION: Pretreatment of enamel surfaces with air abrasion increased the bond strength of fissure sealant, but pretreatment with Er,Cr:YSGG laser did not increase the effectiveness of conventional acid etching of enamel in sealant bonds.

A multidisciplinary approach to the treatment of traumatically intruded immature incisors. A 6-year follow up.

This report presents a case of 10 years old girl who was referred to the pediatric dentistry clinic sustaining a sever trauma led to crown fracture and intrusive luxation of immature maxillary incisors. Antibiotic therapies were initiated at first visit, and after surgical exposure both intruded and extruded teeth were endodontically treated by calcium hydroxide. Orthodontic repositioning was performed and root canal filling with gutta-percha was accomplished. Six years after orthodontic repositioning, clinical and radiographical examinations revealed satisfactory apical and periodontal conditions.