Effects of diabetes on oxidative stress, periodontal ligament fiber orientation, and matrix metalloproteinase 8 and 9 expressions during orthodontic tooth movement.

OBJECTIVES: To evaluate the influence of diabetes on oxidative stress, periodontal ligament (PDL) orientation, and matrix metalloproteinase (MMP) 8 and 9 expressions during orthodontic tooth movement in a rat model. MATERIALS AND METHODS: An orthodontic appliance was placed in 60 Sprague-Dawley rats divided into three groups: normoglycemics (n = 20) and two streptozotocin-induced diabetic groups, one untreated (n = 20) and one insulin-treated (n = 20). At 24, 48, and 72 h and 1 week, rats were sacrificed. At each time point, myeloperoxidase (MPO) and malondialdehyde (MDA) were quantified by spectrophotometry, tooth movement was evaluated by micro-CT analysis, and hematoxylin and eosin staining was used to evaluate PDL fiber orientation and immunohistochemistry staining with semi-quantitative H-score analysis of MMP-8 and MMP-9 was performed.. RESULTS: At 24 h, MPO activity was significantly higher in untreated-diabetics than normoglycemics. At 24 and 48 h, the MDA level in untreated-diabetic rats was significantly higher than in normoglycemics and insulin-treated animals. At 72 h and 1 week, PDL fibers were oriented significantly more irregularly in untreated-diabetics than in normoglycemics. At all time points, MMP-8 and MMP-9 expressions were significantly higher in both diabetic groups than in the normoglycemic group. After the second day, tooth movement was significantly greater in untreated-diabetics than in the insulin-treated and normoglycemic groups. CONCLUSIONS: Mechanical stress in untreated-diabetic rats produces more inflammatory response, oxidative stress, tooth movement, PDL disorganization, and MMP-8 and MMP-9 expressions than among normoglycemics. Insulin reverses these effects, favoring the reorganization of periodontal ligament. CLINICAL RELEVANCE: Our results suggest that the application of orthodontic force in diabetic patients would increase inflammation and delay periodontal restructuring. Insulin would partly reverse this situation although glycemic decompensation episodes may occur. For these reasons, the periods between fixed orthodontic appliance activations should be of sufficient duration to allow adequate tissue recovery.

Second primary molar hypomineralisation and drugs used during pregnancy and infancy. A systematic review.

OBJECTIVES: Hypomineralised second primary molars (HSPM) are due to idiopathic hypomineralisation that affects from 1- to 4-s primary molars, and its aetiology remains unclear. Our objective was to systematically review studies in which the investigators had studied the association between HSPM and drug use during pregnancy and the first year of life. MATERIALS AND METHODS: A systematic search for publications until July 2018 was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. No restrictions were placed on year of publication. The PECO Question was as follows: P, children exposed to drugs during pregnancy and the first year of life; E, drugs to which mothers, during pregnancy and their offspring were exposed; C, control groups from studies with the same characteristics not exposed to drugs during pregnancy and the first year of life; and O, relationship between drug exposure during pregnancy and the first year of life and HSPM. Two reviewers extracted the data and assessed the risk of bias using the Newcastle-Ottawa Scale criteria. RESULTS: We initially identified 986 articles, or which seven were selected for review: two case-control studies, one cross-sectional studies and four cohort studies. Four studies reported data on drug consumption during pregnancy and four investigated drug use during the first year of life and the occurrence of enamel defects in primary dentition. CONCLUSIONS: There is no clear evidence that the use of drugs during pregnancy and during the first year of life is associated with HSPM. Further well-designed prospective studies are needed. CLINICAL RELEVANCE: Determining the etiological factors related to the development of HSPM would help to establish preventive protocols in patients at potential risk. As HSPM is predictive of molar incisor hypomineralisation (MIH), the application of preventive protocols would avoid complications in both the primary and permanent dentition.

Correction to: Microleakage in class V composite and compomer restorations following exposure to a colutory prescribed for the treatment of xerostomy.

In the original publication of the article, one of the author names was published incorrectly as José L. Calvo. The correct name is José L. Calvo-Guirado.

Correction to: Metallic ion content and damage to the DNA in oral mucosa cells of children with fixed orthodontic appliances.

Due to an unfortunate turn of events, the surname of the fourth author appeared incorrectly in the original publication and should have read Calvo Guirado.

Influence of fluoride varnish on shear bond strength of a universal adhesive on intact and demineralized enamel.

The aim was to evaluate the effect of fluoride varnish on the shear bond strength (SBS) on polished and non-polished intact and demineralized enamel. Bovine incisors (half demineralized) were used. Bifluorid 12™ was applied. Bonding was made with Futurabond®M + and GrandioSO, 24 h and 7 days after varnishing. In some groups, varnish was removed by polishing before bonding. SBS was measured. Fracture type was determined by stereomicroscopy and scanning electron microscope (SEM) observations of the enamel surface were made. Between-group differences were determined by one-way ANOVA and the Tukey test. Associations between study factors and fracture modes were analysed using contingency tables and Pearson's chi-squared test. For intact enamel, SBS on varnished enamel at 24 h was significantly less than in the other groups. SBS recovered 7 days after varnishing. Varnish elimination after 24 h significantly increased the SBS. However, removal at 7 days did not modify SBS. SBS on demineralized enamel groups was significantly less than in intact enamel, except for demineralized enamel varnished and removed at 7 days. Demineralized enamel was associated with cohesive enamel fractures and intact enamel with cohesive fractures of the composite and adhesive fractures. SEM of varnish surfaces showed a homogenous layer scattered with amorphous precipitate. In conclusion, on intact enamel fluoride varnish had a negative effect on SBS at 24 h, which disappeared after 7 days. On demineralized enamel, varnish did not reduce SBS at either time. Polishing the varnished enamel surface showed a similar SBS to intact enamel after 7 days.

In vitro study of the antibacterial properties and microbial colonization susceptibility of four self-etching adhesives used in orthodontics.

OBJECTIVES: 1. To determine the in vitro antibacterial effectiveness of the orthodontic bonding Transbond XT (3M Unitek) and four self-etching adhesives with possible use in orthodontic bonding (Clearfil Protect Bond, CPB; Clearfil Self-etching Bond, CSB; Transbond Plus Self-Etching Primer, TSEP; iBond) against Streptococcus mutans and Lactobacillus gasseri in order to compare that capacity among the adhesives and with respect to Transbond XT; 2. To determine the bacterial adhesion capacity of the above mentioned microorganisms to the tested adhesives. MATERIALS AND METHODS: The inhibitory effects of the adhesives against S. mutans and L. gasseri were examined using the agar diffusion method with Whatman No.1 5mm disks loaded with 15 µl of adhesive, UV polymerized, layered on previously inoculated BHI and MRS plates incubated microaerobically for 48 hours at 37 degree C. Data were analysed with Kruskal-Wallis (P < 0.05) and Mann-Whitney tests, applying the Bonferroni correction (P < 0.003). Bacterial adhesion was studied with scanning electron microscopy. RESULTS: Only CPB and iBond produced a clear growth inhibition halo against S. mutans and L. gasseri (P < 0.0001). iBond was the only tested product to which the bacteria adhere profusely, particularly S. mutans. CONCLUSIONS: CPB has shown antimicrobial properties in vitro, and, provided the limitations of an in vitro study, the use of this self-etching adhesive may contribute to reduce microbial decalcification, making the use of this self-etching adhesive an attractive option for bracket bonding.

Canting of the occlusal plane: perceptions of dental professionals and laypersons.

OBJECTIVES: To determine if canting of the occlusal plane influences esthetic evaluation of the smile among orthodontists, dentists and laypersons. STUDY DESIGN: A frontal photo of a smile with 0 occlusal plane canting in relation to the bipupillary plane was modified using Adobe Photoshop C3 (Adobe Systems Inc, San José, California) to generate two images with occlusal plane inclinations of 2 and 4 . The three images were evaluated esthetically by orthodontists (n=40) general dentists (n=40) and laypersons (n=40). Each image was awarded a score as follows: 1=esthetically acceptable; 2=moderately acceptable; 3=esthetically unacceptable. Evaluators also placed the three images in order in preference. Data were analyzed using the Kruskal-Wallis (p<0.05) and the Mann-Whitney tests, applying the Bonferroni Correction (p<0.016). RESULTS: No significant differences (p> 0.05) were found between the three groups for 0 and 2 cants (median for orthodontists=1; general dentists=1; laypersons=1). Orthodontists (median score=3) made evaluations of the image with 4 occlusal plane that were significantly different from general dentists (median=2) and laypersons (median=2). All three groups put the 0 image in first place in order of esthetic acceptability, the 2 image in second place and the 4 image in third place. Orthodontists placed the 0 image in first place with significantly greater frequency (p<0.016) than laypersons. CONCLUSIONS: Occlusal plane canting of 0 and 2 were evaluated as esthetically acceptable by the three groups. The 4 occlusal plane cant was evaluated more negatively by orthodontists than by general dentists and laypersons. All three groups placed the 0 image in first place of esthetic acceptability, 2 in second place and 4 in third. Orthodontists put the 0 image in first place with significantly greater frequency than laypersons.

In vitro study of force decay of latex and non-latex orthodontic elastics.

The aim of this study was to evaluate the force decay of two brands of orthodontic elastics, both offering latex and non-latex products. Samples were subjected to continuous stretching, measuring force at 5 seconds, 8 hours, and 24 hours in both dry and wet conditions. Five hundred samples were used, GAC® and Lancer® 0.25 inch and 4 oz, divided into testing sample sizes of n = 25 per group. For the dry test, elastics were kept stretched to three times their internal diameter for 5 seconds (initial force), 8 hours, and 24 hours; for the wet test, they were stretched for 8 and 24 hours. Both brands showed initial forces significantly greater than those specified by the manufacturers (P < 0.05). Comparing wet/dry conditions, there was a greater force loss in the wet medium than the dry. As for elastic composition (latex or non-latex), the only significant difference found was between Lancer elastics with and without latex in dry conditions, force loss being greater for latex-free elastics. Comparing brands, there was greater force loss with GAC than with Lancer. Comparing elastic force at the eight-hour mark and the twenty-four hour mark to the initial force (only in wet conditions), GAC latex and non-latex and Lancer latex elastics showed significantly less force at eight and twenty four hours than initially. On the other hand, Lancer non-latex was the only type of elastics that did not show a significant decrease in its initial elastic characteristics at eight hours in wet conditions. Nevertheless, Lancer non-latex did show significantly less force in wet conditions at twenty four-hours than the forces observed initially and at eight-hours.

Orthodontic and dentofacial orthopedic treatments in patients with ectodermal dysplasia: a systematic review.

OBJECTIVE: The objective of this systematic review was to determine the orthodontic and dentofacial orthopedic treatments carried out in patients with ectodermal dysplasia to facilitate functional and aesthetic rehabilitation. METHODS: The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. We systematically searched PubMed, Web of Science, Scopus, Scielo, LILACS, EBSCOhost and Embase databases up to 6 January 2022. We included articles describing patients with any type of ectodermal dysplasia who received orthodontic or dentofacial orthopedic treatment to facilitate functional and aesthetic oral rehabilitation. The search was not restricted by language or year of publication. The quality of the studies was assessed using the Joanna Briggs Institute Quality Assessment Scale of the University of Adelaide for case series and case reports. The review was registered at the University of York Centre for reviews (CRD42021288030). RESULTS: Of the initial 403 studies found, 29 met the inclusion criteria. After applying the quality scale, 23 were left for review-21 case reports and 2 case series. The initial age of patients ranged from 34 months to 24 years. Thirteen studies were on hypohidrotic and/or anhidrotic ectodermal dysplasia, of which two were X-chromosome linked. In one study, the patient had Wiktop syndrome, and in nine the type of ectodermal dysplasia was not specified. The duration of treatment was 7 weeks to 10 years. The treatments described were: fixed orthodontic appliances or simple acrylic plates designed for tooth movement, including leveling and aligning, closing of diastemata, retraction of impacted teeth in the dental arch; clear aligners; fixed and/or removable appliances for the correction of skeletal and/or dentoalveolar relationships; palatal expanders in combination with face masks for orthopedic traction of the maxilla; and orthognathic surgery. Only three studies provided cephalometric data. CONCLUSION: The level of evidence of the articles reviewed was low and most orthopedic and dentofacial orthodontic treatments described were focused on correcting dental malpositioning and jaw asymmetries and not on stimulating growth from an early age. Studies with greater scientific evidence are needed to determine the best treatment for these patients.

Spanish Paediatricians' Knowledge, Attitudes and Practices Regarding Oral Health of Children under 6 Years of Age: A Cross-Sectional Study.

BACKGROUND: Early Childhood Caries (ECC) is a prevalent chronic pathology, and it has a negative impact on the oral and general health of the child patient. AIM: To evaluate the knowledge, attitudes and practices of Spanish paediatricians regarding early childhood caries according to the professional's years of experience. MATERIAL AND METHODS: A cross-sectional questionnaire was conducted by Spanish paediatricians via WhatsApp and e-mails from January to April 2021. Data were analysed using Chi-squared test, Fisher's exact test and Cramer's V test. RESULTS: There were a total of 359 participants. Most respondents were women (81.3%) with up to 10 years of professional experience (31.2%) in primary health care and public health. In most cases, participants had an excellent knowledge of primary dentition (90.8%), but they ignored (56%) when the first visit to the dentist should occur. Regarding the aetiological factors of caries, oral hygiene and prevention, a lower rate of knowledge was observed. The majority of participants (80.8%) were not able to identify white spot lesions and enamel defects (76%). They considered that their knowledge in oral health was deficient, highlighting the need to increase their training. Less experienced paediatricians were found to have higher success rates. CONCLUSIONS: The level of knowledge and attitudes regarding early childhood caries of the evaluated paediatricians should be improved. Paediatricians had difficulties in identifying early caries lesions and enamel defects. Nevertheless, a higher level of knowledge and positive attitudes towards dental caries has been detected among paediatricians with fewer years of professional experience.

Metallic ion content and damage to the DNA in oral mucosa cells of children with fixed orthodontic appliances.

Although the metal devices used in orthodontic treatments are manufactured highly resistance to corrosion, they may still suffer some localized corrosion resulting from the oral cavity conditions. The corrosion causes the release of metals from the alloys used for their manufacture. In this report, we evaluated the in vivo metal ions release of three alloys (stainless steel, titanium and nickel-free) usually used in the orthodontics treatments and its genotoxicity. We applied to 15 patients, between 12 and 16 years, 4 tubes and 20 brackets. Samples from oral mucosa were taken before the treatment and 30 days later. The concentration of the titanium, chromium, manganese, cobalt, nickel, molybdenum and iron were detected using inductively coupled plasma mass spectrometry (ICP-MS). The genotoxicity was measured with a comet assay (Olive moment). The oral mucosa cells in contact with the stainless steel alloy displayed the greatest titanium and manganese concentrations and those in contact with the nickel-free alloy presented the greatest concentration of chromium and iron. Both alloys, stainless steel and nickel-free, induced a higher DNA damage in the oral mucosa cells than the titanium alloy, in which the Olive moment was similar to controls. Based on the results of our study, we can conclude that titanium brackets and tubes are the most biocompatible of the three alloys.

Microleakage in Class V composite and compomer restorations following exposure to a colutory prescribed for the treatment of xerostomy.

The purpose of this study was to evaluate the effect of a colutory (XeroLacer, Lacer), prescribed for the treatment of xerostomy, on microleakage into class V cavities filled with a composite (Z100, 3M ESPE) or a compomer (F2000, 3M ESPE) in combination with either a two-step etch-and-rinse adhesive (Adper Scotchbond 1XT, 3M ESPE) or a self-etching adhesive (Adper Prompt L-Pop, 3M ESPE). Class V cavities were made in the buccal surfaces of 80 bovine lower incisors which were randomly divided into four groups (n = 20): (1) Adper Scotchbond 1XT/Z100; (2) Adper Scotchbond 1XT/F2000; (3) Adper Prompt L-Pop/Z100; and (4) Adper PLP/F2000. All specimens were immersed in distilled water for 3 months and ten specimens of each group were immersed and vibrated in XeroLacer for 2 min three times a day. The specimens were dyed with 1% methylene blue for 24 h. Longitudinal sections were made and percentages of microleakage were determined by image analysis. In distilled water, microleakage with the Adper Scotchbond 1XT/F2000 combination was significantly greater than with Adper Scotchbond 1XT/Z100 or Adper Prompt L-Pop/Z100, and microleakage with Adper Prompt L-Pop/F2000 was significantly greater than that with Adper Prompt L-Pop/Z100. No significant differences were detected among the groups exposed to XeroLacer. However microleakage was significantly less with Adper Scotchbond 1XT/F2000 after exposure to XeroLacer than after immersion in distilled water only. In conclusion, exposure to XeroLacer decreased microleakage into cavities restored with the compomer.

Metallic ions released from stainless steel, nickel-free, and titanium orthodontic alloys: toxicity and DNA damage.

INTRODUCTION: The aims of this study were to determine the amounts of metallic ions that stainless steel, nickel-free, and titanium alloys release to a culture medium, and to evaluate the cellular viability and DNA damage of cultivated human fibroblasts with those mediums. METHODS: The metals were extracted from 10 samples (each consisting of 4 buccal tubes and 20 brackets) of the 3 orthodontic alloys that were submerged for 30 days in minimum essential medium. Next, the determination of metals was performed by using inductively coupled plasma mass spectrometry, cellular viability was assessed by using the tetrazolium reduction assay (MTT assay) (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide), and DNA damage was determined with the Comet assay. The metals measured in all the samples were Ti(47), Cr(52), Mn(55), Co(59), Ni(60), Mo(92), Fe(56), Cu(63), Zn(66), As(75), Se(78), Cd(111), and Pb(208). RESULTS: The cellular viability of the cultured fibroblasts incubated for 7 days with minimum essential medium, with the stainless steel alloy submerged, was close to 0%. Moreover, high concentrations of titanium, chromium, manganese, cobalt, nickel, molybdenum, iron, copper, and zinc were detected. The nickel-free alloy released lower amounts of ions to the medium. The greatest damage in the cellular DNA, measured as the olive moment, was also produced by the stainless steel alloy followed by the nickel-free alloy. Conversely, the titanium alloy had an increased cellular viability and did not damage the cellular DNA, as compared with the control values. CONCLUSIONS: The titanium brackets and tubes are the most biocompatible of the 3 alloys studied.

The effects of two soft drinks on bond strength, bracket microleakage, and adhesive remnant on intact and sealed enamel.

The purpose of this study was to evaluate the effects of Coca-Cola and Schweppes Limón on bond strength, adhesive remnant, and microleakage beneath brackets. One hundred and twenty upper central incisor brackets were bonded to bovine incisors and divided into three groups: (1) Control, (2) Coca-Cola, and (3) Schweppes Limón. The teeth were submerged in the drinks three times a day for 15 minutes over a 15 day period. Shear bond strength (SBS) was measured with a universal testing machine, and adhesive remnant evaluated using image analysis equipment. Microleakage at the enamel-adhesive and adhesive-bracket interfaces was determined using methylene blue. One hundred and eight teeth were used for scanning electron microscopy to determine the effect of the drinks on intact and sealed enamel. SBS and adhesive remnant data were analysed using the Kruskal-Wallis test (P < 0.05) and microleakage using the Kruskal-Wallis and Mann-Whitney tests applying Bonferroni correction (P < 0.017). No significant differences were found in SBS and adhesive remnant between the groups (P > 0.05). Microleakage at the enamel-adhesive interface for groups 2 and 3 was significantly greater than for group 1 (P < 0.017). At the adhesive-bracket interface, microleakage was significantly greater in group 2 than in group 1 (P < 0.017) while microleakage in group 3 did not differ significantly from either group 1 or 2 (P < 0.017). The drinks produced enamel erosion, loss of adhesive and microleakage. Coca-Cola and Schweppes Limón did not affect the SBS of brackets or the adhesive remnant.

Effectiveness of a toothpaste and a serum containing calcium silicate on protecting the enamel after interproximal reduction against demineralization.

To evaluate the effectiveness of a calcium silicate/phosphate fluoridated tooth paste and a serum compared with a toothpaste containing hydroxyapatite on protecting the enamel after interproximal reduction against demineralization. 3 sets of eleven incisors were created. The teeth underwent interproximal enamel reduction (IER) of 0.5 mm. Each set was allocated to one of three groups: (1) Brushing without toothpaste (control group); (2) Vitis toothpaste + Remin Pro; (3) Regenerate toothpaste + Regenerate Serum. The agents were applied three times a day and specimens subjected to demineralization cycles for 30 days. The weight percentages of calcium (Ca) and phosphorous (P) were quantified by X-ray microfluorescence spectroscopy. Surface microhardness measurements and electron scanning microscopy (SEM) observations were made. Ca data and the Ca/P ratio were significantly higher in Group 3 than the other groups (p < 0.017), while P was significantly lower in Group 3 (p < 0.017). No significant differences were found between Groups 1 and 2 (p > 0.017). Group 3 showed significantly higher microhardness values (p < 0.05) than Group 1. No significant differences were found for other comparisons between groups (p < 0.05). SEM images showed less demineralization in Group 3. The application of a calcium silicate/phosphate fluoridated tooth paste (Regenerate advance) and a dual serum (Regenerate advance enamel serum) protect the enamel with interproximal reduction against demineralization. Therefore, this treatment could be used to prevent the dissolution of hydroxyapatite after IER.

Effect of saliva contamination on bracket failure with a self-etching primer: a prospective controlled clinical trial.

INTRODUCTION: The aim of this study was to evaluate in vivo the effect of saliva contamination at different stages of the bonding procedure on the bond failure rate and the adhesive remaining on teeth after debonding brackets bonded with a hydrophilic self-etching primer (Transbond Plus self-etching primer [TSEP], 3M Unitek, Monrovia, Calif). METHODS: This was a prospective controlled clinical trial. The sample consisted of 46 patients with similar treatment plans and mechanotherapies. Stainless steel brackets (n = 531) were bonded with TSEP. The patients were divided into 2 groups: contamination with saliva before TSEP application and contamination with saliva after TSEP application. In both groups, saliva was applied in a split-mouth design. Diagonally opposite quadrants were allocated to either the contaminated group (contamination before [153 teeth] or after [115 teeth] TSEP application) or to the uncontaminated control group (263 teeth). Recording of failed brackets involved only first-time failures, and the observation period was a minimum of 6 months. RESULTS: The chi-squared test showed no significant differences (P = 0.11) in bracket failures between the groups. Kaplan-Meier survival analysis detected no significant differences in the survival rates between the 3 groups (P = 0.51). Most bond failures occurred during the first 3 months. In all 3 groups, the adhesive remaining on teeth after debonding tended to be less than half. CONCLUSIONS: These findings suggest that saliva contamination before or after application of self-etching primer does not increase the clinical risk of bond failure.

The in vitro effect of repeated bonding on the shear bond strength with different enamel conditioning procedures.

The aims of this study were to evaluate the effect on shear bond strength (SBS), adhesive remnant, and enamel surface of repeated bonding of new brackets on the same tooth using different methods of enamel conditioning. One hundred and thirty-five bovine incisors were used. Brackets were bonded to enamel using one of the following conditioning procedures: (1) 37 per cent phosphoric acid, (2) 37 per cent phosphoric acid (prior to first bond but not for further bonds), (3) Transbond Plus Self Etching Primer (TSEP), and (4) non-rinse-conditioner (NRC). Brackets were sequentially bonded and debonded three times following the same conditioning procedure with the exception of group 2 where 37 per cent phosphoric acid was not reapplied prior to the second and third bonding sequences. SBS and adhesive remnant were evaluated for each debond. Scanning electron microscopy observations were made for each conditioning sequence. Statistical analysis was undertaken using ANOVA, Mann-Whitney, and Kruskal-Wallis tests. Bond strength and adhesive remnant values were similar across the four groups for the first and second bonding sequences. At the third sequence, SBS was significantly less (P < 0.008) for group 2 (5.71 +/- 1.56 MPa) than for group 1 (9.42 +/- 2.75 MPa) and the adhesive remnant was significantly lower (P < 0.008) for group 2 (6.93% +/- 3.34) than for the other groups (group 1: 16.95 +/- 4.99 per cent, group 3: 14.40 +/- 5.11 per cent, and group 4: 14.60 +/- 5.33 per cent). When comparing the SBS and adhesive remnant of the three bonding/debonding sequences within each group, both the SBS and adhesive remnant for group 2 (SBS: 5.71 +/- 1.56 MPa and adhesive remnant: 6.93 +/- 3.34%) at the third sequence were significantly less (P < 0.017) than at the first (SBS: 10.44 +/- 3.55 MPa and adhesive remnant: 13.81 +/- 5.59%) and second (SBS: 9.23 +/- 2.69 MPa and adhesive remnant: 15.32 +/- 6.85%) sequences. Enamel changes were similar across all groups. TSEP and NRC produced bonds that were similar to acid etching. When acid etching is used, it is possible to avoid etching for a second bond but not for following bonds.

Effect of water contamination on the shear bond strength of five orthodontic adhesives.

OBJECTIVES: To evaluate the shear bond strength and site of failure of brackets bonded to dry and wet enamel. STUDY DESIGN: 50 teeth were divided into ten groups of 5 teeth each (10 surfaces). In half the groups enamel was kept dry before bonding, and in the other half distilled water was applied to wet the surface after etching. The following groups were established: 1) Acid/Transbond-XT (dry/wet) XT; 2) Transbond Plus Self Etching Primer (TSEP)/Transbond-XT paste (dry/wet); 3) Concise (dry), Transbond MIP/Concise (wet), 4) FujiOrtho-LC (dry/wet); 5) SmartBond (dry/wet). Brackets were bonded to both buccal and lingual surfaces. Specimens were stored in distilled water (24 hours at 37 degrees C) and thermocycled. Brackets were debonded using a Universal testing machine (cross-head speed 1 mm/min). Failure sites were classified using a stereomicroscope. RESULTS: No significant differences in bond strength were detected between the adhesives under wet and dry conditions except for SmartBond, whose bond strength was significantly lower under dry conditions. For all the adhesives most bond failures were of mixed site location except for Smartbond, which failed at the adhesive-bracket interface. CONCLUSIONS: Under wet conditions the bonding capacity of the adhesives tested was similar than under dry conditions, with the exception of SmartBond which improved under wet conditions.

High-throughput DNA sequencing of microbiota at interproximal sites.

Objective: The oral microbiota has been deeply studied by high-throughput sequencing techniques. However, although the interproximal regions have one of the highest caries rates in the oral cavity, information about the bacterial composition at those sites is scarce. Methods: In this study, we used 16S rRNA Illumina sequencing to describe the microbiota associated to interproximal regions at two time points. In addition, dental plaque samples at the vestibular and lingual surfaces from the same teeth were also analysed at the two time points. Results: Interproximal-associated microbiota was found to be similar to already described bacterial communities in other mouth niches. Streptoccocus, Veillonella, Rothia, Actinomyces, Neisseria, Haemophilus and Fusobacterium were the most abundant genera in this oral region. Statistical analyses showed that the microbiota from interproximal sites was more similar to that sampled from the vestibular surfaces than to the lingual surfaces. Interestingly, many potentially cariogenic bacteria such as Scardovia, Atopobium or Selenomonas were over-represented in the interproximal regions in comparison with vestibular and lingual sites. Conclusion: The microbiota at interproximal regions appears to be specific and stable through time. Potentially pathogenic bacteria may increase caries development risk and gingival inflammation at those sites.