Five year evaluation of the complications observed in porcelain fused to metal (PFM) crowns placed at a university hospital.

OBJECTIVE: To determine the frequency of complications in crowns cemented over a 5-year period in a tertiary care hospital and also to report the survival of these crowns. METHODS: The retrospective cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from March 2017 to March 2018 and comprised porcelain fused-to-metal crowns placed on the anterior or posterior teeth that were fabricated at the institutional laboratory and were placed in institutional dental clinics in the preceding 5 years. Porcelain-fused to-metal The crowns were clinically and radio-graphically evaluated in a duration of two months for presence/absence of complications. Factors associated with the failure of the crowns, their survival and the impact of covariates, like gender, flossing and bruxism, on the survival time were determined. Data was analysed using SPSS 22. RESULTS: There were 150 crowns related to 107 patients who had a mean age of 45.0±11.4 years. The most common complication observed was open proximal contacts 9(6%) followed by de-cementation 8(5.3%), porcelain chipping 9(6%) and abutment fracture 2(1.3%). The 5-year survival rate of the crowns was 127(84.7%). The mean follow-up time was 57.2±1.0 months. Overall, year-wise survival of PFM crowns for one year till five years was 147 (98%), 144 (96%), 135 (90%), 130 (86%) and 119 (79%) respectively. CONCLUSIONS: The porcelain-fused-to-metal crowns had a high 5-year survival rate. Open proximal contacts represented the most common complication.

Comparison of clinical bond failure rates and bonding times between two adhesive precoated bracket systems.

OBJECTIVE: To compare the clinical bracket failure rate and bonding time differences between Adhesive Precoated Flash-Free (APCF) and Adhesive Precoated Plus (APCP) bracket systems. METHODS: Thirty-three patients (7 male and 26 female) with a mean age of 17.2 ± 3.6 years and permanent dentition were included in the study. Total of 660 brackets were bonded by 1 operator with the use of a split-mouth design, and bracket failure rates were observed over 6 months. Bracket bonding time of each group was also evaluated. Bracket failure rates were evaluated by means of chi-square test. One-way analysis of variance (ANOVA) and Tukey honestly significant difference tests were used to evaluate the bonding time differences between groups. RESULTS: The overall, APCF, and APCP bracket failure rates were 1.21%, 1.81%, and 1.51%, respectively. Chi-square test revealed significant differences (P <0.01) between groups in bracket failure rates. The upper left APCP group showed significantly (P <0.05) more failure than the other groups. One-way ANOVA test (P <0.001) showed statistically significant bonding time differences between groups. Bonding time of APCF brackets was significantly shorter than the bonding time of APCP brackets for the same quadrants. Chi-square test did not reveal significant differences (P >0.05) between groups according to adhesive remnant index scores. CONCLUSIONS: Compared with APCP brackets, APCF brackets can reduce the bonding time without increasing bracket failure rate.

Impact of Dentinal Tubule Orientation on Dentin Bond Strength.

This study aimed to determine the impact of dentinal tubule orientation on dentin bond strength to provide a reference for clinical cavity preparation in resin-bonded restoration. Patients aged 13-16 years were selected, including 18 males and 21 females. Forty-eight human maxillary first premolars from orthodontic extractions were chosen to prepare the test models with the dentinal tubule orientations perpendicular and parallel to the bonding substrate. The test models in the vertical and parallel groups were divided into three groups: total-etching with 20% phosphoric acid, total-etching with 35% phosphoric acid and self-etching, with the dentinal tubule surfaces bonded with composite resin blocks in each group. After the standard test models of dentinal tubule-composite resin blocks were placed in distilled water and stored at 37°C for 24 h, shearing tests were performed using a universal material testing machine at a crosshead speed of 0.5 mm/min. The bond strength values in the vertical group were 19.33±1.59 MPa for the 20% phosphoric acid group, 21.39±2.34 MPa for the 35% phosphoric acid group, and 16.88±1.54 MPa for the self-etching group. The bond strength values in the parallel group were 24.53±1.99 MPa for the 20% phosphoric acid group, 25.16±2.88 MPa for the 35% phosphoric acid group, and 20.83±1.99 for the self-etching group. After using same total-etching adhesive, the shear bond strength of the parallel group was higher than that of the vertical group, and the difference was statistically significant (P<0.05). Regardless of vertical group or parallel group, the difference in the bond strength value between the total-etching groups and the self-etching group was statistically significant (P<0.05). It was concluded that the dentin bonding substrate which was parallel to the direction of the dentin tubule achieved an improved bond strength; the total-etching adhesives achieved higher bond strengths in dentin bond than the self-etching adhesives.

[Comparison of adhesive seal morphology between APC™ PLUS and APC™ Flash-Free Adhesive Coated brackets]. / Comparaison du joint de colle entre les attaches préencollées APC™ PLUS et les attaches APC™ Flash-Free.

INTRODUCTION: Does the new adhesive-coated APC™ Flash-Free bracket from the 3M Unitek® group simplify the bonding protocol without compromising precision? OBJECTIVES: The aim of this study was to compare the morphology of the adhesive joint between the classic APC™ PLUS adhesive-coated brackets and APC™ Flash-Free brackets. MATERIALS AND METHODS: In vitro bonding of esthetic brackets in the CLARITY™ ADVANCED range was performed to compare the morphology of the excess flash between APC™ PLUS and APC™ Flash-Free brackets. RESULTS: No statistically significant difference was found concerning the morphology of the excess flash between APC™ PLUS and APC™ Flash-Free brackets. A statistically significant difference was found regarding the thickness of the adhesive between the two types of bracket. The adhesive used for the APC™ Flash-Free brackets was significantly thicker than for the APC™ PLUS brackets (P=0.0001). Adhesive thickness was also more homogeneous on the APC™ Flash-Free brackets (P=0.001 for the relative difference). CONCLUSION: The adhesive is thicker but adhesive homogeneity is greater with APC™ Flash-Free brackets than with APC™ PLUS brackets.

Effect of fixed orthodontic appliances on nonmicrobial salivary parameters.

OBJECTIVES:: To examine possible changes in the levels of salivary antioxidants, C-reactive protein (CRP), cortisol, pH, proteins, and blood in patients treated with fixed orthodontic appliances. MATERIALS AND METHODS:: Salivary samples from 21 orthodontic patients who met specific inclusion criteria were collected before the beginning of orthodontic treatment (T0; baseline), 1 hour after bonding (T1), and 4-6 weeks after bonding (T2). Oxidant-scavenging ability (OSA) was quantified using a luminol-dependent chemiluminescence assay. Cortisol and CRP levels were measured using immunoassay kits. pH levels and presence of proteins and blood in the samples were quantified using strip-based tests. RESULTS:: A significant decrease in salivary pH was observed after bonding ( P = .013). An increase in oxidant-scavenging abilities during orthodontic treatment was detected, but the change was not statistically significant. Cortisol and CRP levels slightly increased after bonding, but the difference was small without statistical significance. Changes in the presence of proteins and blood were also insignificant. CONCLUSIONS:: Exposure to fixed orthodontic appliances did not show a significant effect on salivary parameters related to inflammation or stress, with the exception of a significant but transient pH decrease after bonding.

Biomechanical Effects of Bonding Pericervical Dentin in Maxillary Premolars.

INTRODUCTION: Pericervical dentin (PCD) loss may increase root fracture propensity in root-filled teeth. This study evaluated the impacts of bonding PCD with composite resin (CR) on radicular microstrain distribution and load at failure of root-filled maxillary premolars. METHODS: Ten single-canal maxillary premolars decoronated 2 mm coronal to the cementoenamel junction (CEJ) had canals enlarged with ProTaper Universal instruments (Dentsply Tulsa Dental Specialties, Tulsa, OK) to F3. They were root filled with gutta-percha (GP) to the CEJ and restored with Cavit (3M Deutschland GmbH, Neuss, Germany) (GP group, n = 5) or 6 mm apical to the CEJ and restored with bonded CR to simulate bonding of PCD (bonded PCD group, n = 5). Digital moiré interferometry was used to evaluate pre- and postoperative whole-field microstrain distribution in the root dentin under physiologically relevant loads (10-50 N). Another 30 premolars, similarly treated as groups 1 and 2 or left untreated as controls (n = 10/group), were subjected to cyclic loads (1.2 million cycles, 45 N, 4 Hz) followed by uniaxial compressive load to failure. Mechanical data were analyzed with 1-way analysis of variance and the post hoc Tukey test at a 5% level of significance. RESULTS: Microstrain distribution showed bending and compressive patterns at the coronal and apical root dentin, respectively. In the GP group, microstrain distribution was unaltered. In the bonded-PCD group, different microstrain distribution suggested stiffening at the PCD. The load at failure did not differ significantly for the GP, bonded PCD, and control groups (P > .05). CONCLUSIONS: CR bonding of PCD might impact the biomechanical responses in maxillary premolar roots at low-level continuous loads. The effect of this impact on root fracture loads when subjected to cyclic load warrants further investigation.

Does orthodontic treatment have a permanent effect on tooth color? : A systematic review and meta-analysis.

OBJECTIVES: Aim of this systematic review was to assess the effect of orthodontic treatment with fixed appliances on the tooth color of patients. METHODS: Nine databases were searched up to May 2017 for clinical cohort studies on the effect of fixed appliance treatment on tooth color. After elimination of duplicate studies, data extraction, and risk of bias assessment according to the Cochrane guidelines, random effects meta-analyses of mean differences (MD) or means and their 95% confidence intervals (CIs) were performed, followed by GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessment of the quality of evidence. RESULTS: Three nonrandomized and one randomized study with a total of 138 patients (46% male, 54% female) with average age of 15.7 years were included. Tooth color of treated patients was significantly altered during or after orthodontic treatment (4 studies; average of 3.2 ∆E units; 95% CI = 2.0-4.4 ∆E units), which was more than the variation among controls (1 study; MD = 1.9 ∆E units; 95% CI = 1.7-2.2 ∆E units). However, the quality of evidence was very low, due to the inclusion of nonrandomized studies, bias, and imprecision. Re-analysis of raw study data indicated that significant differences in clinically discernable treatment-induced color changes were seen between chemically and light-cured adhesives and among the various tooth categories. CONCLUSION: Existing evidence of very low quality indicates that orthodontic treatment might be associated with alterations of tooth color, which are however not consistently clinically discernible. Treatment-induced color alterations might be dependent on bonding material and tooth type, but evidence supporting this is weak.

The Effects of Cavity Preparation and Composite Resin on Bond Strength and Stress Distribution Using the Microtensile Bond Test.

OBJECTIVES: To evaluate the effect of flowable bulk-fill or conventional composite resin on bond strength and stress distribution in flat or mesio-occlusal-distal (MOD) cavity preparations using the microtensile bond strength (µTBS) test. METHODS: Forty human molars were divided into two groups and received either standardized MOD or flat cavity preparations. Restorations were made using the conventional composite resin Z350 (Filtek Z350XT, 3M-ESPE, St Paul, MN, USA) or flowable bulk-fill (FBF) composite resin (Filtek Bulk Fill Flowable, 3M-ESPE). Postgel shrinkage was measured using the strain gauge technique (n=10). The Z350 buildup was made in two increments of 2.0 mm, and the FBF was made in a single increment of 4.0 mm. Six rectangular sticks were obtained for each tooth, and each section was used for µTBS testing at 1.0 mm/min. Polymerization shrinkage was modeled using postgel shrinkage data. The µTBS data were analyzed statistically using a two-way analysis of variance (ANOVA), and the postgel shrinkage data were analyzed using a one-way ANOVA with Tukey post hoc test. The failure modes were analyzed using a chi-square test (α=0.05). RESULTS: Our results show that both the type of cavity preparation and the composite resin used affect the bond strength and stress distribution. The Z350 composite resin had a higher postgel shrinkage than the FBF composite resin. The µTBS of the MOD preparation was influenced by the type of composite resin used. Irrespective of composite resin, flat cavity preparations resulted in higher µTBS than MOD preparations ( p<0.001). Specifically, in flat-prepared cavities, FBF composite resin had a similar µTBS relative to Z350 composite resin. However, in MOD-prepared cavities, those with FBF composite resin had higher µTBS values than those with Z350 composite resin. Adhesive failure was prevalent for all tested groups. The MOD preparation resulted in higher shrinkage stress than the flat preparation, irrespective of composite resin. For MOD-prepared cavities, FBF composite resin resulted in lower stress than Z350 composite resin. However, no differences were found for flat-prepared cavities. CONCLUSIONS: FBF composite resin had lower shrinkage stress than Z350 conventional composite resin. The µTBS of the MOD preparation was influenced by the composite resin type. Flat cavity preparations had no influence on stress and µTBS. However, for MOD preparation, composite resin with higher shrinkage stress resulted in lower µTBS values.

A Systematic Review of the Survival and Complication Rates of All-Ceramic Resin-Bonded Fixed Dental Prostheses.

PURPOSE: The aim of this systematic review was to investigate the survival and complication rates of all-ceramic resin-bonded fixed dental prostheses (RBFDPs). MATERIALS AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied. A systematic search was conducted by an electronic search in PubMed, EMBASE, Cochrane Library, and CNKI databases complemented by a manual search. Only clinical studies on all-ceramic RBFDPs with a mean follow-up period of at least 3 years qualified for data analyses. RESULTS: Among 1503 screened articles, one randomized controlled trial (RCT) and seven prospective or retrospective cohort studies were included in this study. The estimated 5-year survival rate of all-ceramic RBFDPs was 91.2%. Debonding and framework fracture were the two most frequent technical complications, and the estimated 5-year debonding rate and fracture rate were 12.2% and 4.8%, respectively. Additionally, cantilevered all-ceramic RBFDPs had a higher survival rate (p < 0.01), lower debonding rate, (p < 0.05), and fracture rate (p < 0.01) compared with two-retainer all-ceramic RBFDPs. Zirconia ceramic RBFDPs had a lower incidence of failure but a higher debonding rate compared with glass-ceramic RBFDPs (p < 0.01). CONCLUSION: Within the limitations of this systematic review, although all-ceramic RBFDPs have a favorable 5-year survival rate, this rate cannot represent the complete success of the treatment, since it may include typical complications such as debonding and fractures. There is an urgent need for long-term clinical studies, especially for well-designed RCTs on all-ceramic RBFDPs.

Wear profile of canal wall surfaces and bond strength of endodontic sealers after in situ acid challenge.

AIM: To evaluate the wear of root wall surfaces, the bond strength of sealers to dentine and the demineralization around root filling materials after canals were exposed to acid challenge in situ. METHODOLOGY: Eighty-seven roots of mandibular incisors were selected. Thirty-two were used in the laboratory bond strength study (n = 8), and 55 in the in situ study (n = 11). Root canals were prepared biomechanically and then filled with gutta-percha and AH Plus, MTA Fillapex, Sealapex or Endofill. For 14 days, 11 participants used intra-oral devices with five sterilized roots (four experimental and one control - only canal prepared). Drops of sucrose were dripped onto roots allowing the accumulation of biofilm on canal surfaces. Roots were removed, sectioned and analysed for the following: bond strength of filling material using a push-out test and also wear profile and dentine demineralization using confocal microscopy. Bond strength (MPa) was evaluated by two-way anova and Tukey test (α = 0.05), and wear profile was assessed by Kruskal-Wallis and t-tests (α = 0.05). RESULTS: AH Plus had the highest bond strength values. Intermediate results were found in roots with MTA Fillapex and Endofill, whilst Sealapex had inferior results (P < 0.05). No significant differences were found amongst root thirds (P > 0.05). For wear profile, samples were associated with degradation of the filling materials after exposure to the oral environment (P < 0.05). Roots had signs of demineralization around the filling material when Sealapex and Endofill were used. CONCLUSIONS: Sealers were not able to prevent degradation of the adhesive interface and dentine. AH Plus and MTA Fillapex had superior bond strength to dentine and less intense demineralization around the root filling.

Quantitative analysis of enamel on debonded orthodontic brackets.

INTRODUCTION: Iatrogenic damage to the tooth surface in the form of enamel tearouts can occur during removal of fixed orthodontic appliances. The aim of this study was to assess debonded metal and ceramic brackets attached with a variety of bonding materials to determine how frequently this type of damage occurs. METHODS: Eighty-one patients close to finishing fixed orthodontic treatment were recruited. They had metal brackets bonded with composite resin and a 2-step etch-and-bond technique or ceramic brackets bonded with composite resin and a 2-step etch-and- bond technique, and composite resin with a self-etching primer or resin-modified glass ionomer cement. Debonded brackets were examined by backscattered scanning electron microscopy with energy dispersive x-ray spectroscopy to determine the presence and area of enamel on the base pad. RESULTS: Of the 486 brackets collected, 26.1% exhibited enamel on the bonding material on the bracket base pad. The incidences of enamel tearouts for each group were metal brackets, 13.3%; ceramic brackets, 30.2%; composite resin with self-etching primer, 38.2%; and resin-modified glass ionomer cement, 21.2%. The percentage of the bracket base pad covered in enamel was highly variable, ranging from 0% to 46.1%. CONCLUSIONS: Enamel damage regularly occurred during the debonding process with the degree of damage being highly variable. Damage occurred more frequently when ceramic brackets were used (31.9%) compared with metal brackets (13.3%). Removal of ceramic brackets bonded with resin-modified glass ionomer cement resulted in less damage compared with the resin bonding systems.

Enamel color changes following orthodontic treatment.

OBJECTIVE: To evaluate and compare the effect of various orthodontic bonding systems and clean up procedures on quantitative enamel colour change. MATERIALS AND METHODS: A literature search was done to identify the studies that assessed the quantitative enamel colour change associated with the various bonding systems and cleanup procedures. Electronic database (Pub Med, Cochrane and Google Scholar) were searched. First stage screening was performed and the abstracts were selected according to the initial selection criteria. Full text articles were retrieved and analyzed during second stage screening. The bibliographies were reviewed to identify additional relevant studies. RESULTS: Sixteen full text articles were retrieved. Six were rejected because the methodology was different. There was significant enamel colour change following orthodontic bonding, debonding and clean up procedures. CONCLUSION: Self-etching primers produce less enamel colour change compared to conventional etching. Resin Modified GIC produces least colour change compared to other light cure and chemical cure systems. Polishing following the clean-up procedure reduces the colour change of the enamel.

Decalcification prevention around orthodontic brackets bonded to bleached enamel using different topical agents.

BACKGROUND: The present study was conducted to evaluate the effect of different topical agents utilized for prevention of enamel decalcification around orthodontic brackets bonded to bleached and non-bleached enamel. METHODS: Human maxillary premolars (n = 120) were divided into two equal groups. Teeth in group I were left without bleaching while those in group II were bleached with Vivastyle gel. Metal brackets were bonded to all the teeth using light-cured adhesive. Each group was divided into six equal subgroups (A, B, C, D, E, and F). In subgroup A, no material was applied (control). In subgroups B, C, D, E, and F, the following materials were applied respectively: Profluorid varnish, Enamel Pro Varnish, Ortho-Choice Ortho-Coat, GC Tooth Mousse, and GC MI Paste Plus. All teeth were cycled in a demineralization solution/artificial saliva for 15 days. Laser fluorescence was used to measure the level of enamel mineralization. The data were statistically analyzed. RESULTS: Regarding the non-bleaching subgroups, all studied material revealed significant demineralization reduction in comparison to the control subgroup (P < 0.05). Ortho-Choice Ortho-Coat revealed the highest significant effect while GC Tooth Mousse showed the least effect. In bleached subgroups, Profluorid varnish, Enamel Pro Varnish, and Ortho-Choice Ortho-Coat significantly reduced demineralization (P < 0.05) while either GC MI Paste Plus or GC Tooth Mousse had no significant effects (P > 0.05). CONCLUSIONS: Ortho-Choice Ortho-Coat, and Profluorid and Enamel Pro varnishes could be utilized successfully to reduce enamel demineralization around brackets bonded to either bleached or non-bleached enamel. GC MI Paste Plus and GC Tooth Mousse were effective only in non-bleached enamel.

Addition of ammonium-based methacrylates to an experimental dental adhesive for bonding metal brackets: Carious lesion development and bond strength after cariogenic challenge.

INTRODUCTION: In this study, we evaluated the caries inhibition and shear bond strength achieved with the addition of the antibacterial monomer [2-(Methacryloyloxy)ethyl] trimethylammonium chloride (MADQUAT) to an adhesive used to bond orthodontic brackets. METHODS: Experimental adhesives were formulated with addition of 0% (control), 5%, or 10% MADQUAT followed by measurement of the degree of conversion. These adhesives were used to lute brackets to the enamel of premolars (n = 30). Biofilm from a microcosm model was cultivated in half of the specimens under cariogenic challenge for 5 days. The brackets were subjected to a shear bond strength test followed by measurement of the internal hardness of the enamel around the brackets to calculate the integrated mineral loss. RESULTS: The addition of MADQUAT slightly increased the degree of conversion. Adhesive containing 10% MADQUAT significantly reduced the integrated mineral loss around the bracket but also resulted in the lowest values of bond strength. No effects on bond strength and integrated mineral loss were observed with the addition of 5% MADQUAT to the adhesive. The cariogenic challenge did not affect the bond strength and the failure mode. CONCLUSIONS: MADQUAT was effective to reduce the integrated mineral loss only when added to the adhesive at a concentration of 10% despite the reduction of bond strength.

Comparison between universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode.

This aim of this study was to compare universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode. Three universal adhesives - Clearfil Universal, G-Premio Bond, and Scotchbond Universal Adhesive - and three-two-step self-etch adhesives - Clearfil SE Bond, Clearfil SE Bond 2, and OptiBond XTR - were used. The initial shear bond strength and shear fatigue strength of resin composite bonded to adhesive on dentin in self-etch mode were determined. Scanning electron microscopy observations of fracture surfaces after bond strength tests were also made. The initial shear bond strength of universal adhesives was material dependent, unlike that of two-step self-etch adhesives. The shear fatigue strength of Scotchbond Universal Adhesive was not significantly different from that of two-step self-etch adhesives, unlike the other universal adhesives. The shear fatigue strength of universal adhesives differed depending on the type of adhesive, unlike those of two-step self-etch adhesives. The results of this study encourage the continued use of two-step self-etch adhesive over some universal adhesives but suggest that changes to the composition of universal adhesives may lead to a dentin bond fatigue durability similar to that of two-step self-etch adhesives.

Statistical study on bracket debonding rate with the win lingual technique.

The aim of this study is to present the results of a statistical inquiry measuring the bracket debonding rate using the WIN lingual technique. This inquiry was performed in the Odontology Unit at the Rothschild Hospital in the framework of the Lingual Orthodontics University Diploma at Paris VII university. Results were gathered by 8 orthodontic practitioners during two years of training from all their patients treated with the WIN lingual technique. The sample study comprised 33 patients treated exclusively with the WIN lingual technique. The 8 practitioners filled in a questionnaire relating to bracket bond failure in their patients in the course of treatment. In all, sixty-two questionnaires were analyzed. The data were then computed using the statistical tool of R software version 3.1.3. The results of this analysis demonstrate the reliability of the WIN system evidenced by an average of 2.1 bracket bond failures over the two-year treatment period, i.e. approximately 1 bracket per patient per year. Given the right conditions, (precise prescription, compliance with bonding protocols), the bond failure rate can be lower still, even compared with the buccal technique or relative to other lingual techniques. The benefits of lingual appliances, particularly in the WIN system, are essential to clinicians in their daily practice in order to optimize the quality and duration of their treatments with a view to ensuring patient satisfaction.

Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors.

OBJECTIVES: To test the following two hypotheses: 1) different types of retainers result in distinct levels of biomarkers in gingival crevicular fluid (GCF) and 2) the retainer bonded to all mandibular anterior teeth induces more detrimental outcomes to the periodontium. SETTING AND SAMPLE POPULATION: The Department of Orthodontics at the University of Florida. The population consisted of individuals in the retention phase of orthodontic treatment. MATERIAL AND METHODS: This was a cross-sectional study that enrolled 36 individuals. Subjects in group 1 had retainers bonded to the mandibular canines only. Group 2 consisted of individuals having retainers bonded to all mandibular anterior teeth. Group 3 included patients using mandibular removable retainers. After clinical examination, GCF was collected from the mandibular incisor and biomarker levels were compared between the groups. RESULTS: Plaque accumulation and gingivitis differed significantly among groups, with the highest median values in group 2 subjects. Pairwise comparison of the groups with respect to gingivitis showed significant differences between groups 1 and 2. Significant differences among groups were detected for RANKL, OPG, OPN, M-CSF, MMP-3, and MMP-9. The ratio RANKL/OPG was significantly higher in group 2 subjects, with pairwise comparisons indicating that groups 1 and 2 differed from group 3. CONCLUSION: An association was found between orthodontic retention groups and GCF biomarker levels, which should be further explored in longitudinal studies. The presence of retainers bonded to all anterior teeth seems to increase plaque accumulation and gingivitis.

One-step partial or complete caries removal and bonding with antibacterial or traditional self-etch adhesives: study protocol for a randomized controlled trial.

BACKGROUND: Current concepts in conservative dentistry advocate minimally invasive dentistry and pulp vitality preservation. Moreover, complete removal of carious dentin in deep carious lesions often leads to pulp exposure and root canal treatment, despite the absence of irreversible pulp inflammation. For years, partial caries removal has been performed on primary teeth, but little evidence supports its effectiveness for permanent teeth. Furthermore, the recent development of new antibacterial adhesive systems could be interesting in the treatment of such lesions. The objectives of this study are to compare the effectiveness of partial versus complete carious dentin removal in deep lesions (primary objective) and the use of an antibacterial versus a traditional two-step self-etch adhesive system (main secondary objective). METHODS/DESIGN: The DEep CAries Treatment (DECAT) study protocol is a multicenter, randomized, controlled superiority trial comparing partial versus complete caries removal followed by adhesive restoration. The minimum sample size required is 464 patients. Two successive randomizations will be performed (allocation ratio 1:1): the first for the type of excavation (partial versus complete) and the second (if no root canal treatment is required) for the type of adhesive (antibacterial versus traditional). For the two objectives, the outcome is the success of the treatment after 1 year, measured according to a composite outcome of five FDI criteria: material fracture and retention, marginal adaptation, radiographic examination (including apical pathologies), postoperative sensitivity and tooth vitality, and carious lesion recurrence. DISCUSSION: The study will investigate the interest of a conservative approach for the management of deep carious lesions in terms of dentin excavation and bioactive adhesive systems. The results may help practitioners achieve the most efficient restorative procedure to maintain pulp vitality and increase the restoration longevity. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02286388 . Registered in November 2014.

Inadvertent tooth movement with fixed lingual retainers.

Fixed retainers are effective in maintaining the alignment of the anterior teeth more than 90% of the time, but they can produce inadvertent tooth movement that in the most severe instances requires orthodontic retreatment managed with a periodontist. This is different from relapse into crowding when a fixed retainer is lost. These problems arise when the retainer breaks but remains bonded to some or all teeth, or when an intact retainer is distorted by function or was not passive when bonded. In both instances, torque of the affected teeth is the predominant outcome. A fixed retainer made with dead soft wire is the least likely to create torque problems but is the most likely to break. Highly flexible twist wires bonded to all the teeth appear to be the most likely to produce inadvertent tooth movement, but this also can occur with stiffer wires bonded only to the canines. Orthodontists, general dentists, and patients should be aware of possible problems with fixed retainers, especially those with all teeth bonded, because the patient might not notice partial debonding. Regular observations of patients wearing fixed retainers by orthodontists in the short term and family dentists in the long term are needed.