Interferon-gamma inducible protein 16 and type I interferon receptors expression in experimental apical periodontitis induced in wild-type mice.

AIM: The aim of this study was to evaluate the IFI16 and IFN-α/ß receptors expression during the genesis and development of experimental apical periodontitis (AP) in mice teeth. METHODOLOGY: Apical periodontitis was induced in the lower first molars of 40 C57BL/6 mice. They were divided according to the experimental periods 2, 7, 14, 21 and 42 days (n = 8 per group). Five animals were used as a control group (without AP). Specimens were submitted to histological processing for description of the inflammatory process, immunostaining for the presence/absence and localization of IFI16 and IFN-α/ß receptors (qualitative and semi-quantitative analysis) and tartrate-resistant acid phosphatase (TRAP) histoenzimology. RESULTS: The results showed a gradual development of AP over the experimental times. The expression of IFI16 was noticeably more exacerbated in the experimental early period (day 2) whilst the lowest expression was observed in the control group (p = .02). For IFN-α/ß receptors, a higher intensity staining was observed 42 days after AP induction, that was statistically different from the control group (p = .02). In addition, the number of TRAP-positive cells was higher on the later periods (days 21 and 42; p < .001). CONCLUSION: IFI16 protein expression was highest during the early periods after AP induction in mice teeth, whilst IFN-α/ß receptor expression was highest after AP became established.

Effect of manual and electrical brushing on the enamel of sound primary teeth and teeth with induced white spot lesions.

PURPOSE: To evaluate the effect of different electrical brushing systems on the surface roughness and wear profile of the enamel of sound primary teeth and teeth with induced white spot lesions. METHODS: 45 specimens were obtained from sound primary incisors, and the buccal surface was divided into four parts: sound enamel; enamel with white spot lesions; sound enamel with brushing; and enamel with white spot lesions and brushing. Specimens were randomly divided into three groups (n =15), according to the different brushing systems: Group 1 - Electric rotating toothbrush (Kid's Power Toothbrush - Oral B); Group 2 - Sonic electric toothbrush (Baby Sonic Toothbrush); and Group 3 - Manual toothbrush (Curaprox infantil) (control). The specimens were analyzed for surface roughness and wear profile. Data were analyzed by appropriate statistical tests, with a significance level of 5%. RESULTS: Regarding the surface roughness, no significant difference was observed between the groups. However, with respect to the wear profile, Group 1 caused significantly higher wear in the sound tooth enamel and in the presence of white spot lesions, in comparison to the other brushing systems (2 and 3) (P< 0.05), which did not cause wear. Manual and electric brushing (rotational and sonic) did not increase surface roughness in primary tooth enamel. However, the electric rotational brushing caused significant wear of the sound and demineralized enamel surface of primary teeth. CLINICAL SIGNIFICANCE: None of the toothbrushing systems tested caused significant alterations on sound dental enamel. However, rotational toothbrushing on enamel of primary teeth with white spot lesion increased wear.

The effect of immediate controlled forces on periodontal healing of teeth replanted after short dry time in dogs.

BACKGROUND/AIM: The extra-alveolar dry period and storage medium in which a tooth is kept prior to replantation remain critical factors affecting the survival and repair potential of the periodontal ligament in avulsed teeth. When replantation is not immediate, replacement root resorption (RRR) is the most common complication. The aim of this histological study was to evaluate the effect of immediate controlled-orthodontic forces in periodontal healing of replanted teeth in a canine model. MATERIAL AND METHODS: Sixty maxillary and mandibular premolar roots were endodontically treated in vivo and subsequently hemisected and extracted. Roots were replanted after an extraoral dry time of 20 minutes and randomly assigned to two experimental groups: Group 1: root was stabilized with a flexible and passive bracket/stainless steel wire splint for 2 weeks; Group 2: root was stabilized with a flexible bracket/NiTi wire splint activated with orthodontic elastics for 2 weeks. After 4 months, the dogs were euthanized, and all specimens were processed for histology and microscopically evaluated. RESULTS: The mean percentage of RRR for Group 2 was 3.17 compared with 12.13 in Group 1. Eighty-three percent of specimens from Group 2 exhibited similar healing to the negative control group, compared to 60.5% of the specimens from Group 1. No statistical difference was found in periodontal healing between experimental groups. CONCLUSION: Immediate application of mild and controlled orthodontic forces was not detrimental to the periodontal healing of teeth replanted after 20 minutes extraoral dry time, although no significant improvement on periodontal healing was observed.

Stepwise Excavation Allows Apexogenesis in Permanent Molars with Deep Carious Lesions and Incomplete Root Formation.

This study evaluated the stepwise excavation technique in 138 permanent molars with deep carious lesions and incomplete root formation within a 24-month clinical and radiographic follow-up period. In 96.7% of the cases, success was observed (no pain, integrity of restoration margins, absence of radiographic alterations and apexogenesis). The cases of failure (3.3%) were due to the loss of the temporary restoration. In conclusion, the stepwise excavation is a promising technique for permanent teeth with deep carious lesions and incomplete root formation as a minimally invasive approach because it allows the preservation of pulp vitality and occurrence of apexogenesis.

Factors involved in the treatment sought immediately after traumatic dental injuries in Brazilian children.

AIM: The aim of this study was to evaluate demographic and clinical factors involved in the immediate seeking of care after traumatic dental injury (TDI) in Brazilian children. MATERIALS AND METHODS: Records from 74 patients, age ranged 1-11 years, who sought treatment at the School of Dentistry of Ribeirão Preto at University of São Paulo, Brazil, were collected. Data was analyzed using the Epi Info 7.0 software by t-test, odds ratio calculation, Chi-square, or Fisher's exact tests. RESULTS: Twenty-three (31.1%) sought dental treatment immediately and 51 (68.9%) did not seek dental treatment immediately. The most common type of trauma was lateral luxation (44.6%). In primary teeth, 31 cases (60.78%) involved the soft tissue and 16 (39.2%) involved hard tissue injuries. While in permanent teeth, 20 cases (40%) involved soft tissue and 24 (60%) involved hard tissue injuries had more traumas in the hard tissue (P = 0.04). The type of injury and dentition was not associated with the time that the guardians sought dental treatment (P > 0.05). None of the factors were involved in immediately seeking care after TDI. CONCLUSION: Moreover, the majority of parents/caregivers did not immediately seek dental treatment after TDI, regardless of the type of injury.

Ovariectomy Exacerbates Apical Periodontitis in Rats with an Increase in Expression of Proinflammatory Cytokines and Matrix Metalloproteinases.

INTRODUCTION: The aim of this study was to evaluate the gene expression of proinflammatory cytokines, matrix metalloproteinases (MMPs), and cathepsin K in apical periodontitis (AP) and the volume of lesions in ovariectomized and sham-operated rats. METHODS: Twenty 12-week-old female Wistar rats were subjected to ovariectomy (OVX) or sham surgery. After 9 weeks, access cavities were prepared in the maxillary and mandibular first molars, pulp tissue was removed, and canals were exposed to the oral environment during 21 days for the induction of AP. The groups were as follows: sham, OVX, sham+AP, and OVX+AP. Animals were euthanized, and blocks containing the maxillary first molar and the surrounding bone were removed for quantification of proinflammatory cytokines cathepsin K and MMP genes by real-time polymerase chain reaction. The hemimandibles containing the mandibular first molars were used for analysis of the AP lesion volume by micro-computed tomographic imaging. RESULTS: AP in OVX rats showed an increased expression of interleukin 1 beta, tumor necrosis factor alpha, interleukin 6, MMP-8, and MMP-13 (P < .05). OVX alone, without AP induction, did not affect the expression of the evaluated genes. Additionally, AP induced an increase in cathepsin K expression, without significant differences between AP in the sham and OVX groups (P > .05). Micro-computed tomographic imaging showed a significantly greater AP lesion mean volume in OVX compared with sham animals (P < .05). CONCLUSIONS: AP lesions in ovariectomized rats are larger and have an increased expression of proinflammatory cytokines and MMPs, indicating that the infection combined with ovariectomy has an important role in the regulation of these signaling molecules and enzymes during the development of AP. Based on that, it may be assumed that the hypoestrogenic condition aggravates inflammation and degradation of extracellular matrix components in AP, which may provide insight into understanding the development of AP in female postmenopausal patients.

Resin luting materials: Tissue response in dog's teeth.

The aim of this study was to evaluate radiographically and histologically the pulpal and periapical response to self-adhesive (Rely X™ Unicem) and self-etching and self-curing (Multilink(®)) resin-based luting materials in deep cavities in dogs' teeth. Deep class V cavities (0.5-mm-thick dentin) were prepared in 60 canine premolars and the following materials were applied on cavity floor: Groups I/V-RelyX™ Unicem; Groups II/VI-Multilink(®); Groups III/VII-zinc phosphate cement (control) and; Groups IV/VIII-gutta-percha (control). Cavities were restored with silver amalgam. Animals were euthanized after 10 days (groups I-IV) and 90 days (groups V-VIII). Tooth/bone blocks were radiographed and processed for histopathological evaluation of pulp and periapical tissue response to the materials. All materials presented similar histopathological features and radiographic findings at both periods. The pulp tissue was intact. The apical and periapical regions and periodontal ligament thickness were normal. No inflammatory cells, resorption of mineralized tissue (dentin, cementum, and alveolar bone) or bacteria were observed. The lamina dura was intact and no areas of periapical bone rarefaction or internal/external root resorption were observed radiographically. It can be concluded that Rely X™ Unicem and Multilink(®) caused no adverse tissue reactions and may be indicated for cementation of indirect restorations in deep dentin cavities without pulp exposure.