Degradation of resin-dentin bonds of etch-and-rinse adhesive system to primary and permanent teeth

The aim of this in vitro study was to compare the degradation of resin-dentin bonds of an etch-and-rinse adhesive system to primary and permanent teeth. Flat superficial coronal dentin surfaces from 5 primary second molars and 5 permanent third molars were etched with phosphoric acid and bonded with an adhesive system (Adper Single Bond 2, 3M ESPE). Blocks of resin composite (Z250, 3M ESPE) were built up and the teeth sectioned to produce bonded sticks with a 0.8 mm(2) cross-sectional area. The sticks of each tooth were randomly divided and assigned to be subjected to microtensile testing immediately (24 h) or after aging by water storage (6 months). Data were analyzed by two-way repeated measures ANOVA and Tukey post hoc test (alpha = 0.05). Failure mode was evaluated using a stereomicroscope (400x). Microtensile values significantly decreased after the 6 months aging, independent of the dentin substrate. In 24 h, the values obtained to primary dentin were lower compared with permanent dentin. This difference was not maintained after aging. Adhesive/mixed failure was predominant in all experimental groups. In conclusion, degradation of resin-dentin bonds of the etch-and-rinse adhesive system occurred after 6 months of water storage; however, the reduction in bond strength values was higher for permanent teeth.

Fracture susceptibility of endodontically treated teeth

Aim: To assess the influence of cervical preparation on fracture susceptibility of roots. Material and methods: During root canal instrumentation, the cervical portions were prepared with different taper instruments: I: no cervical preparation; II: #30/.08; III: #30/.10; IV: #70/.12. The specimens were sealed with the following filling materials (n = 8), A: unfilled; B: Endofill/gutta-percha; C: AH Plus/gutta-percha; D: Epiphany SE/Resilon. For the fracture resistance test, a universal testing machine was used at 1 mm per minute. Results: anova demonstrated difference (P < 0.05) between taper instruments with a higher value for group I (205.3 +/- 77.5 N) followed by II (185.2 +/- 70.8 N), III (164.8 +/- 48.9 N), and IV (156.7 +/- 41.4 N). There was no difference (P > 0.05) between filling materials A (189.1 +/- 66.3 N), B (186.3 +/- 61.0 N), C (159.7 +/- 69.9 N), and D (176.9 +/- 55.2 N). Conclusions: Greater cervical wear using a #70/.12 file increased the root fracture susceptibility, and the tested filling materials were not able to restore resistance.

Description of immature stages of Phelypera schuppeli (Boheman, 1834) with comments on natural history (Coleoptera: Curculionidae: Hyperinae)

Immatures of the Phelypera schuppeli (Boheman, 1834) (Curculionidae; Hyperinae; Cepurini) are described, illustrated and compared with available descriptions of larvae and pupae of Hyperini. Immatures and adults from midwest (Dourados, Mato Grosso do Sul; Pirenopolis, Goias) and southeast Brazil (Bauru, Sao Paulo) were found on leaves of the host plant, Pachira aquatica Aubl. (Malvaceae, formerly Bombacaceae), a tree used as an ornamental plant in many Brazilian frost-free cities. Larvae of P. schuppeli are exophytic, brightly colored, eruciform and possess abdominal ambulatory ampullae, resembling larvae of Lepidoptera. Mature larvae can spin globular lattice-like cocoons where pupation takes place. Data in the field and under laboratory conditions confirmed previously published biological observations on P. schuppeli. Additional information about defensive behaviors, process of cocoon construction and natural enemies, such as the larval predator Supputius cinticeps (Stal, 1860) (Hemiptera: Pentatomidae) and the prepupal and pupal parasitoid Jaliscoa nudipennis Boucek, 1993 (Hymenoptera: Pteromalidae), are reported.

Dental pulp stem cells express proteins involved in the local invasiveness of odontogenic myxoma

Little is known about the histogenesis of the odontogenic myxoma (OM). Dental pulp stem cells could be candidate precursors of OM because both OM and the dental pulp share the same embryological origin: the dental papilla. For the purpose of comparing OM and stem cells, this study analyzed the expression of two proteins related to OM invasiveness (MMP-2 and hyaluronic acid) in human immature dental pulp stern cells (hIDPSCs). Three lineages of hIDPSCs from deciduous and permanent teeth were used in this study. Immunofluorescence revealed positive reactions for MMP-2 and hyaluronic acid (HA) in all hIDPSCs. MMP-2 appeared as dots throughout the cytoplasm, whereas HA appeared either as diffuse and irregular dots or as short fibrils throughout the cytoplasm and outside the cell bodies. The gene expression profile of each cell lineage was evaluated using RT-PCR analysis, and HA was expressed more intensively than MMP-2. HA expression was similar among the three hIDPSCs lineages, whereas MMP-2 expression was higher in DL-1 than in the other cell lines. The expression of proteins related to OM invasiveness in hIDPSCs could indicate that OM originates from dental pulp stem cells.

Influence of moisture and plaque on the performance of a laser fluorescence device in detecting caries lesions in primary teeth

The aim of this study was to evaluate the influence of dental plaque and moisture on performance of a laser fluorescence device in detecting occlusal and proximal caries lesions in primary teeth. Fifty-five occlusal and 58 proximal sites on primary molars were evaluated using a DIAGNOdent pen (LFpen) device. For the drying time study, the evaluations were performed in: (I) moist teeth; (II) teeth dried for 3 s, or (III) dried for 15 s. For the plaque study, the evaluations were done in sites: (I) without plaque; (II) with plaque, and (III) after cleaning. Evaluation of the teeth sections in stereomicroscope was the reference standard method. LF pen values, sensitivity, specificity, and accuracy were compared. The values obtained after 15 s of drying were higher than those obtained with moist teeth or dried for 3 s at both occlusal and proximal surfaces. However, there was no change in the performance in detecting caries lesions. With regard to the presence of plaque, there was no significant change in the readings of the device, but specificity was decreased in occlusal surfaces with plaque. At proximal surfaces, however, no significant differences were observed. In conclusion, the moisture conditions do not influence significantly the performance of the LFpen, but the presence of plaque can affect its performance in detecting occlusal caries lesions in primary teeth.

Systemically alendronate was incorporated into dental tissues but did not cause morphological or mechanical changes in rats teeth

This study evaluated the effect of the systemic use of sodium alendronate in rats in vivo. Forty-five Wistar rats aged 36 to 42 days and weighing 200 to 230 g were randomly assigned to a control group (n = 20), which received distilled water, and an experimental group (n = 25), which received 2 weekly doses of 1 mg/kg of chemically pure sodium alendronate. The animals were killed after 60 days of treatment. The tibias were removed for analysis of bone mineral density by dual-energy X-ray absorptiometry (DXA). Then, the maxillary incisors were extracted for analysis of the mineralized dental tissues using fluorescence spectroscopy (FS), scanning electron microscopy (SEM), bright field microscopy (BFM), and cross-sectional microhardness (CSMH) testing. DXA and CSMH data were subjected to statistical analysis by Kruskal-Wallis test (5% significance level). The experimental group presented higher bone mineral density than the control group by DXA. FS analysis revealed presence of alendronate in the mineralized dental tissues of the specimens of the experimental group. Significant morphological differences were not found by SEM and BFM. Enamel and dentin (100 and 300 mu m from the dentinoenamel junction) CSMH data did not show significant difference between the control and experimental groups. Based on the obtained results, we conclude that while alendronate increased the bone mineral density and was incorporated into the mineralized dental tissues it did not cause significant alterations in the morphology and microhardness of rat incisor enamel and dentin. Microsc. Res. Tech. 75:12651271, 2012. (C) 2012 Wiley Periodicals, Inc.

Antimicrobial Photodynamic Therapy for the Treatment of Teeth with Apical Periodontitis: A Histopathological Evaluation

Introduction: This study evaluated the in vivo response of apical and periapical tissues of dogs' teeth with apical periodontitis after one-session endodontic treatment with and without antimicrobial photodynamic therapy (aPDT). Methods: Sixty root canals with experimentally induced apical periodontitis were instrumented and assigned to 4 groups receiving aPDT and root canal filling (RCF) or not: group aPDT+/RCF- (n = 20): aPDT (photosensitizer phenothiazine chloride at 10 mg/mL for 3 minutes and diode laser [2 = 660 nm, 60 mW/cm(2)] for 1 minute) and RCF in the same session; group aPDT+/RCF (n = 10); group aPDT /RCF+ (n = 20), and group aPDT /RCF (n = 10). Teeth were restored, and the animals were killed after 90 days. Sections from the maxillas and mandibles were stained with hematoxylin-eosin and Mallory trichrome and examined under light microscopy. Descriptive (ie, newly formed apical mineralized tissue, periapical inflammatory infiltrate, apical periodontal ligament thickness, and mineralized tissue resorption) and quantitative (ie, periapical lesion size and number of inflammatory cells) microscopic analysis was performed. Quantitative data were analyzed by the Kruskal-Wallis and Dunn tests (alpha =.05). Results: In the aPDT-treated groups, the periapical region was moderately/severely enlarged with no inflammatory cells, moderate neoangiogenesis and fibrogenesis, and the smallest periapical lesions. Conclusions: Although apical closure by mineralized tissue deposition was not achieved, the absence of inflammatory cells, moderate neoangiogenesis, and fibrogenesis in the periapical region in the groups treated with aPDT indicate that this can be a promising adjunct therapy to cleaning and shaping procedures in teeth with apical periodontitis undergoing one-session endodontic treatment. (J Endod 2012;38:360-366)

Finite element analysis of stress distribution in anchor teeth in surgically assisted rapid palatal expansion

The treatment of a transverse maxillary deficiency in skeletally mature individuals should include surgically assisted rapid palatal expansion. This study evaluated the distribution of stresses that affect the expander's anchor teeth using finite element analysis when the osteotomy is varied. Five virtual models were built and the surgically assisted rapid palatal expansion was simulated. Results showed tension on the lingual face of the teeth and alveolar bone, and compression on the buccal side of the alveolar bone. The subtotal Le Fort I osteotomy combined with intermaxillary suture osteotomy seemed to reduce the dissipation of tensions. Therefore, subtotal Le Fort I osteotomy without a step in the zygomaticomaxillary buttress, combined with intermaxillary suture osteotomy and pterygomaxillary disjunction may be the osteotomy of choice to reduce tensions on anchor teeth, which tend to move mesiobuccally (premolar) and distobuccally (molar)

Clinical, radiographic and histologic analysis of the effects of pulp capping materials used in pulpotomies of human primary teeth

Aim: To compare the clinical, radiographic and histological responses of the pulp to mineral trioxide aggregate (MTA), calcium hydroxide (CH) and Portland cement (PC) when used as a pulpotomy agent in human primary teeth. Study design: Forty-five mandibular primary molar teeth were randomly assigned to CH, MTA or PC groups and treated by pulpotomy technique. Methods: The teeth were treated by conventional pulpotomy technique, differing only in the capping material for each group. Clinical and radiographic evaluations were recorded at 6-, 12- and 24-month follow-up. Teeth in the regular exfoliation period were further processed for histologic analysis. Statistics: The teeth were treated by conventional pulpotomy technique, differing only in the capping material for each group. Clinical and radiographic evaluations were recorded at 6-, 12- and 24-month follow-up. Teeth in the regular exfoliation period were further processed for histologic analysis. Statistics: Clinically and radiographically, the MTA and PC groups showed 100 % success rates at 6, 12 and 24 months. In CH group, several teeth presented clinical and radiographic failures detected throughout the follow-up period, and internal resorption was a frequent radiographic finding. Histologic analysis revealed the presence of dentine-like mineralised material deposition obliterating the root canal in the PC and MTA groups. CH group presented, in most of the sections, necrotic areas in the root canals. Conclusions: MTA and PC may serve as effective materials for pulpotomies of primary teeth as compared to CH. Although our results are very encouraging, further studies and longer follow-up assessments are needed in order to determine the safe clinical indication of Portland cement.

Maxillary sinus and posterior teeth: accessing close relationship by cone-beam computed tomographic scanning in a brazilian population

Introduction: This study aimed to evaluate the close proximity established between the maxillary sinus floor and posterior teeth roots apices by using cone-beam computed tomographic scanning. Methods: The relationship of maxillary sinuses and posterior teeth roots, which were divided into 2 groups, was analyzed using i-CAT Vision software (Imaging Sciences, Hatfield, PA). Group 1 included all root apices found in close contact with the maxillary sinus floor without sinus floor elevation, whereas group 2 included all root apices that were protruded within the sinus producing an elevation of the bony cortical. Results: A total of 100 maxillary sinuses and 601 roots apices were evaluated. Group 1 presented 130 of 601 (21.6%) roots and group 2 presented 86 of 601 (14.3%) roots. Conclusions: The second molar mesiobuccal root apex is frequently found in close proximity with the sinus floor, and the relation between these anatomic structures should be considered in order to prevent an iatrogenic procedure and minimize the risks from an infectious disease within the sinus

Fracture resistance of endodontically treated teeth restored with different intraradicular posts with different lengths

Aim: This study compared the resistance to fracture of endodontically treated teeth restored with different intraradicular posts with different lengths and full coverage metallic crowns. Methods: Sixty extracted human canine teeth were randomly divided into 6 groups. Groups CP5, CP75 and CP10 were restored using custom cast post and core (CP) and groups PF5, PF75 and PF10 were restored with provisional pre-fabricated tin post (PF) and composite resin core at 5 mm, 7.5 mm and 10 mm of intraradicular length, respectively. The specimens were submitted to dynamic cyclic loading and those that resisted to this load were submitted to load compression using a universal testing machine. Compressive load was applied at a 45-degree angle to the long axis of the tooth until failure. Results: Kruskal-Wallis one-way analysis of variance by ranks showed statistically significant differences among the groups (p<0.0001). However, when the means were compared using the Tukey’s test, significant differences were noted between groups CP5 and CP10 and between groups CP10 and PF5. All groups presented root fractures and post displacements during mechanical cycling. All teeth in groups CP5 and PF5 failed the dynamic cycling test. Conclusions: This study showed that increasing intraradicular post length also increases resistance to fracture of endodontically treated teeth. On the other hand, most endodontically treated teeth restored with pre-fabricated tin posts (provisional posts) failed in the dynamic cycling test

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

Objective: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS). Material and Methods: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0 – 10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results. Results: Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF. Conclusion: These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation.

Prevalence of enamel defects in permanent teeth of patients with complete cleft lip and palate

Objective: To evaluate the prevalence, types, location, and characteristics of enamel defects in anterior permanent teeth of patients with complete unilateral and bilateral cleft lip and palate, as well as the relation with the cleft. Setting: Hospital for Rehabilitation of Craniofacial Anomalies, Bauru, São Paulo, Brazil. Participants: Eighty patients of both genders, 12 years and older, with unilateral or bilateral cleft lip and palate. Methods: A single examiner carried out clinical examination under artificial light with a dental probe and mirror after drying teeth according to the modified DDE index. Results: Seventy-four of 80 patients presented with at least one tooth affected by enamel defects: 165 of 325 evaluated teeth (50.8%) presented enamel defects, with hypoplasia being the most prevalent (50.7%), followed by diffuse opacity (23.1%) and demarcated opacity (18.4%). The most affected tooth was 21 (36.5%), followed by 11 (34%), located at the middle (40%) and incisal (33%) thirds. Most defects occur at the buccal surface (47.7%), followed by the distal (22.7%), the mesial (19%), and the palatal (10.6%) surfaces. A significant relationship was found between the cleft side and enamel defects. Conclusion: Upper anterior teeth of patients with complete cleft lip and palate present a high prevalence of enamel defects; the highest percentage on the cleft side suggests that the cleft does influence the occurrence of enamel defects in permanent teeth.

Effect of experimental Ricinus communis solution for denture cleaning on the properties of acrylic resin teeth

This study evaluated Knoop hardness, surface roughness and color alteration of artificial teeth for dentures after immersion in water, 1% sodium hypochlorite and an experimental solution of 2% Ricinus communis (RC). Thirty specimens of Vipi, Biolux and Trilux were analyzed. Tests of Knoop hardness, surface roughness and color alteration were conducted immediately after specimen preparation (T0) and after two immersion protocols for 15 days (ΔT15) and 183 days (ΔT183). Data variation (ΔT) were subjected to ANOVA and Tukey's test (p<0.05). At ΔT15, Vipi presented hardness increase and Biolux presented the highest variation (p=0.01). RC caused the highest increase in hardness (p=0) and the lowest increase (p=0.005) in roughness. Biolux presented the lowest color alteration (p =0). At ΔT183, Trilux underwent the highest hardness variation (p=0). Biolux presented an increase in roughness (p=0). There was no significant differences in color alteration among the artificial teeth (p=0.06) and among solutions (p=0.08) after 183 days of immersion. All solutions (distilled water, 1% sodium hypochlorite and 2% RC) caused alterations on the analyzed properties. Both immersion protocols caused alterations on the analyzed properties.

Antioxidant activity by DPPH assay of potential solutions to be applied on bleached teeth

The aim of this study was to assess, using the DPPH assay, the antioxidant activity of several substances that could be proposed to immediately revert the problems caused by bleaching procedures. The percentage of antioxidant activity (AA%) of 10% ascorbic acid solution (AAcidS), 10% ascorbic acid gel (AAcidG), 10% sodium ascorbate solution (SodAsS), 10% sodium ascorbate gel (SodAsG), 10% sodium bicarbonate (Bicarb), Neutralize® (NE), Desensibilize® (DES), catalase C-40 at 10 mg/mL (CAT), 10% alcohol solution of alpha-tocopherol (VitE), Listerine® (LIS), 0.12% chlorhexidine (CHX), Croton Lechleri (CL), 10 % aqueous solution of Uncaria Tomentosa (UT), artificial saliva (ArtS) and 0.05% sodium fluoride (NaF) was assessed in triplicate by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical assay. All substances exhibited antioxidant activity, except for CL. AAcidS, AAcidG and VitE exhibited the highest AA% (p<0.05). On the contrary, CHX, NE, LIS and NaF showed the lowest AA% (p<0.05). In conclusion, AAcidS, AAcidG, SodAsS, SodAsG and VitE presented the highest antioxidant activity among substances tested in this study. The DPPH assay provides an easy and rapid way to evaluate potential antioxidants.