Clinical Evaluation of the Effectiveness of Different Bleaching Therapies in Vital Teeth

The aims of this in vivo study were to compare the effectiveness and color stability of at-home and in-office bleaching techniques and to evaluate whether the use of light sources can alter bleaching results. According to preestablished criteria, 40 patients were selected and randomly divided into four groups according to bleaching treatment: (1) at-home bleaching with 10% carbamide peroxide, (2) in-office bleaching with 35% hydrogen peroxide (HP) without a light source, (3) in-office bleaching with 35% HP with quartz-tungsten-halogen light, and (4) in-office bleaching with 35% HP with a light-emitting diode/laser. Tooth shade was evaluated using the VITA Classical Shade Guide before bleaching as well as after the first and third weeks of bleaching. Tooth shade was evaluated again using the same guide 1 and 6 months after the completion of treatment. The shade guide was arranged to yield scores that were used for statistical comparison. Statistical analysis using the Kruskal-Wallis test showed no significant differences among the groups for any time point (P > .01). There was no color rebound in any of the groups. The bleaching techniques tested were equally effective. Light sources are unnecessary to bleach teeth. (Int J Periodontics Restorative Dent 2012;32:303-309.)

Radiographic and Laser Fluorescence Methods Have No Benefits for Detecting Caries in Primary Teeth

Clinical guidelines advise that dentists take radiographs in children to detect caries lesions missed by visual inspection; however, due to the current low caries prevalence in most countries, we hypothesized that the adjunct methods of caries detection would not significantly improve the detection of primary molar lesions in comparison to visual inspection alone. We evaluated the performance of visual inspection, alone or in combination with radiographic and laser fluorescence pen (LFpen) methods, in detecting occlusal and approximal caries lesions in primary molars. Two examiners evaluated children who had sought dental treatment with these diagnostic strategies. The reference standard involved the temporary separation of approximal and operative interventions for occlusal surfaces. The sensitivity, specificity, accuracy and utility of diagnostic strategies were calculated. Simultaneous combined strategies increased sensitivities but decreased specificities. Furthermore, no differences were observed in accuracy and utility, parameters more influenced by caries prevalence. In conclusion, adjunct radiographic and laser fluorescence methods offer no benefits to the detection of caries in primary teeth in comparison to visual inspection alone; hence, present clinical guidelines should be re-evaluated. Copyright (C) 2012 S. Karger AG, Basel

Influence of effective number of pulses on the morphological structure of teeth and bovine femur after femtosecond laser ablation

Femtosecond lasers have been widely used in laser surgery as an instrument for contact-free tissue removal of hard dental, restorative materials, and osseous tissues, complementing conventional drilling or cutting tools. In order to obtain a laser system that provides an ablation efficiency comparable to mechanical instruments, the laser pulse rate must be maximal without causing thermal damage. The aim of this study was to compare the different morphological characteristics of the hard tissue after exposure to lasers operating in the femtosecond pulse regime. Two different kinds of samples were irradiated: dentin from human extracted teeth and bovine femur samples. Different procedures were applied, while paying special care to preserving the structures. The incubation factor S was calculated to be 0.788 +/- 0.004 for the bovine femur bone. These results indicate that the incubation effect is still substantial during the femtosecond laser ablation of hard tissues. The plasma-induced ablation has reduced side effects, i.e., we observe less thermal and mechanical damage when using a superficial femtosecond laser irradiation close to the threshold conditions. In the femtosecond regime, the morphology characteristics of the cavity were strongly influenced by the change of the effective number of pulses. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.4.048001]

Effect of different restorative procedures on the fracture resistance of teeth submitted to internal bleaching

The aim of this study was to evaluate the influence of different restorative procedures on the fracture resistance of endodontically treated teeth submitted to intracoronal bleaching. Fifty upper central incisors were distributed into 5 groups: GI - healthy teeth; GII - endodontically treated teeth sealed with Coltosol; GIII - endodontically treated teeth bleached and sealed with Coltosol; GIV - endodontically treated teeth bleached and restored with composite resin; and GV - endodontically treated teeth bleached and restored with a fiberglass post and composite resin. In the bleached specimens, a cervical seal was made prior to bleaching with 38% hydrogen peroxide. The gel was applied on the buccal surface and in the pulp chamber, and was then light-activated for 45 s. This procedure was repeated three times per session for four sessions, and each group was submitted to the restorative procedures described above. The specimens were submitted to fracture resistance testing in a universal testing machine. There were statistically significant differences among the groups (p < 0.05). The mean value found for GIII was the lowest (0.32 kN) and was significantly different from the values found for GI (0.75 kN), GII (0.67 kN), GIV (0.70 kN), and GV (0.72 kN), which were not significantly different from each other (p > 0.05). The restorative procedures using composite resin were found to successfully restore the fracture resistance of endodontically treated and bleached teeth.

The influence of interdental spacing on the detection of proximal caries lesions in primary teeth

The aim of this study was to investigate the influence of interdental spacing on the performance of proximal caries detection methods in primary molars. In addition, aspects related to temporary tooth separation with orthodontic separators were evaluated. The proximal spaces between the posterior primary teeth (n = 344) of 76 children (4-12 years old) were evaluated before and after temporary separation. Stainless steel strips with different standardized thicknesses were used to measure the presence of biological spacing and the spacing obtained after temporary separation with orthodontic rubber rings. First, the presence of proximal caries lesions was assessed by visual inspection, bitewing radiographs and a pen-type laser fluorescence device (DIAGNOdent pen). Visual inspection after temporary separation with separators was the reference standard method in checking the actual presence of caries. Multilevel analyses were performed considering different outcomes: the performance of the methods in detecting caries lesions and the spacing after temporary separation. The spacing did not influence the performance of the caries detection methods. The maximum spacing obtained with temporary tooth separation was 0.80 mm (mean +/- standard deviation = 0.46 +/- 0.13 mm). The temporary separation was more effective in the upper arch and less effective when an initial biological interdental spacing was present. The biological interdental spacing does not influence the performance of proximal caries detection methods in primary molars, and temporary tooth separation provides spacing narrower than 1.0 mm.

Role of teeth adjacent to implants installed immediately into extraction sockets: an experimental study in the dog

Aim: To evaluate the influence of the presence of both adjacent teeth on the level of alveolar bony crest at sites where implants were installed into the socket immediately after tooth extraction. Material and methods: Six Labrador dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in the right side of the mandible, after full-thickness flap elevation. In the left side of the mandible, an endodontic treatment of the mesial root of the third and fourth premolars was performed. Full-thickness flaps were elevated, the teeth hemisected, and the distal roots removed. Immediately after, implants were bilaterally installed with the margin flush to the buccal bony crest. The implants were placed in the center of the alveolus at the third premolars and toward the lingual bony plate of the alveolus at the fourth premolars. After 3 months of healing, the animals were euthanized. Results: All implants were integrated in mature bone. More bone resorption was observed at the test compared to the control sites. At the buccal aspect, a resorption of 2.8 +/- 0.5 and 1.6 +/- 0.4 mm at the third premolars and of 2.4 +/- 0.6 and 0.8 +/- 0.7 mm at the fourth premolars were found, at the test and control sites, respectively. At the lingual aspect, the bony crest was apically located in relation to the implant shoulder 1.5 +/- 0.3 and 0.5 +/- 0.5 mm at the third premolars and 1.6 +/- 0.6 and 0.3 +/- 1.1 mm at the fourth premolars, at the test and control sites, respectively. A lower buccal bone resorption was found at the control implants placed lingually. Conclusion: Multiple extractions of teeth adjacent to a socket into which implants were installed immediately after, tooth extraction induced more alveolar bone recession compared to sites where the adjacent teeth were preserved. Moreover, an implant placed more lingually yielded less recession of the buccal aspect of the implant.

Capsule Locus Polymorphism among Distinct Lineages of Enterococcus faecalis Isolated from Canals of Root-filled Teeth with Periapical Lesions

Introduction: Although Enterococcus faecalis is a member of the normal microbiota, it is also a major cause of nosocomial infections. Some strains of E. faecalis produce capsule, which contributes to pathogenesis through evasion of host defenses, and its production is dependent on the capsule (cps) operon polymorphism. This study investigated cps locus polymorphism in distinct lineages of E. faecalis isolated from canals of root-filled teeth with periapical lesions. Methods: Twenty-two E. faecalis isolates were evaluated regarding the cps operon polymorphism and genetic diversity. The 3 known CPS types were determined by polymerase chain reaction. This information was correlated with multilocus sequence typing data, which were used to define genetic lineages. Results: cpsA and cpsB were the only detected genes within the cps operon in 62.5% of E. faecalis strains (14/22), indicative of genotype CPS 1, which lacks capsule expression. The essential genes in the cps operon for capsule production were detected in the remaining strains, whereas 3 belonged to genotype CPS 5 and 5 strains to genotype CPS 2. A total of 14 sequence types (STs) were resolved in 22 E. faecalis isolates. Comparison with the E. faecalis international multilocus sequence typing database revealed that 9 STs were previously found, and that the 5 STs were novel. Conclusions: Certain E. faecalis genotypes from canals of root-filled teeth with periapical lesions belong to lineages associated with capsule expression and production of multiple virulence factors, which might account for their increased pathogenic potential. (J Endod 2012;38:58-61)

Macroscopic description of teeth of Azara's agouti (Dasyprocta azarae)

Oliveira F.S., Martins L.L., Canola J.C., Oliveira P.T., Pecora J.D. & Pauloni A.P. 2012. Macroscopic description of teeth of Azara's agouti (Dasyprocta azarae). Pesquisa Veterinaria Brasileira 32(1):93-95. Departamento de Medicina Veterinaria, Universidade Estadual de Maringa, Campus Umuarama, Cx. Postal 65, Umuarama, PR 87501-970, Brazil. E-mail: singaretti@ig.com.br The teeth of Azara's agouti (Dasyprocta azarae) were described macroscopically in order to provide biological data on one of the largest wild rodents of the Americas. Radiography was taken on six heads and the teeth were described. Enamel surrounds the coronal dentin, projects to the roots and is present as parallel inner laminae in buccolingual direction. The dentin is located among the enamel laminae and surrounds the pulp horns. The cementum is located internally to the enamel laminae. On the lingual surface, the cementum and dentin are the outer elements.

Combined effect of anterior malocclusion and inadequate lip coverage on dental trauma in primary teeth

Objectives: The main objective of this study was to investigate whether the interaction of malocclusion (open bite or increased overjet) combined with inadequate lip coverage strengthens its association with traumatic dental injury (TDI) in the primary teeth of preschool children compared to the presence of malocclusion alone. Subjects and methods: A cross-sectional survey was conducted with 376 children aged 3659 months who attended the National Day of Childrens Vaccination. Presence of TDI, tooth discoloration, and sinus tract were evaluated in the children. Variables associated with occlusion were also evaluated. A Poisson regression analysis was performed to verify the association between the explanatory variables and TDI as well as possible interactions among the variables. Then, the prevalence ratio was calculated. Results: The prevalence of TDI was 27.7%. The maxillary central incisor was the most affected tooth, without differences between the right and left sides. Boys had more dental trauma than girls (P = 0.04). The most common TDI was crown fracture restricted to the enamel (58.4%). Children with a combination of anterior open bite or increased overjet and inadequate lip coverage presented a higher prevalence of TDI than when the malocclusions were presented alone (P < 0.05). The same trends were observed when we included, in the final adjusted model, increased overjet instead of open bite. Conclusions: Anterior malocclusions of primary teeth such as increased overjet and anterior open bite are statistically significantly associated with dental trauma only when inadequate lip coverage is also present.

Influence of pulp condition on the accuracy of an electronic foramen locator in posterior teeth: an in vivo study

The aim of this study was to assess, in vivo, the accuracy of the NovApex (R) electronic foramen locator in determining working length (WL) in vital and necrotic posterior teeth. The NovApex (R) was used in 144 canals: 35 teeth with vital pulps (68 canals) and 42 teeth with necrotic pulps (76 canals). WL was measured with the NovApex (R) locator and confirmed using the radiographic method. Differences between electronic and radiographic measurements ranging between 0.0 and 0.4 millimeters were classified as acceptable; differences equal to or greater than 0.5 millimeter were considered unacceptable. Pearson's chi-square test was used to assess the influence of pulp condition on the accuracy of NovApex (R) (alpha = 0.05). Regardless of pulp condition, differences between electronic and radiographic WL measurements were acceptable in 73.61% of the canals. No statistically significant differences in accuracy were observed when comparing vital and necrotic canals (p > 0.05). There were 38 unacceptable measurements. In none of these cases was the file tip located beyond the radiographic apex; in 32, it was located short of the NovApex (R) measurement. Pulp condition had no significant effect on the accuracy of NovApex (R).

Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth

Objective: This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. Material and methods: The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus (TM), Acroseal (R) or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n = 8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (alpha = 0.05). Results: Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal (R) were significantly higher (p<0.05) in the coronal and apical portions of fillings. Conclusion: The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

Microtensile bond strength of resin composite to dentin treated with Er:YAG laser of bleached teeth

The objective of this study was to evaluate the influence of Er:YAG laser (lambda = 2.94 mu m) on microtensile bond strength (mu TBS) and superficial morphology of bovine dentin bleached with 16% carbamide peroxide. Forty bovine teeth blocks (7 x 3 x 3 mm(3)) were randomly assigned to four groups: G1- bleaching and Er:YAG irradiation with energy density of 25.56 J/cm(2) (focused mode); G2 - bleaching; G3 - no-bleaching and Er:YAG irradiation (25.56 J/cm(2)); G4 - control, non-treated. G1 and G2 were bleached with 16% carbamide peroxide for 6 h during 21 days. Afterwards, all blocks were abraded with 320 to 600-grit abrasive papers to obtain flat standardized dentin surfaces. G1 and G3 were Er:YAG irradiated. Blocks were immediately restored with 4-mm-high composite resin (Adper Single Bond 2, Z-250-3 M/ESPE). After 24 h, the restored blocks (n = 9) were serially sectioned and trimmed to an hour-glass shape of approximately 1 mm(2) at the bonded interface area, and tested in tension in a universal testing machine (1 mm/ min). Failure mode was determined at a magnification of 100x using a stereomicroscope. One block of each group was selected for scanning electron microscope (SEM) analysis. mu TBS data was analyzed by two-way ANOVA and Tukey test (alpha = 0.05). Mean bond strengths (SD) in MPa were: G1- 32.7 (5.9)(A); G2- 31.1 (6.3)(A); G3- 25.2 (8.3)(B); G4- 36.7 (9.9).(A) Groups with different uppercase letters were significantly different from each other (p < .05). Enamel bleaching procedure did not affect mu TBS values for dentin adhesion. Er:YAG laser irradiation with 25.56 J/cm(2) prior to adhesive procedure of bleached teeth did not affect mu TBS at dentin and promoted a dentin surface with no smear layer and opened dentin tubules observed under SEM. On the other hand, Er:YAG laser irradiation prior to adhesive procedure of non-bleached surface impaired mu TBS compared to the control group.

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.

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.