Investigation of the cleaning performance of commercial orthodontic cleaning tablets regarding biofilm removal on PMMA test specimens : An ex vivo study.

PURPOSE: The purpose of this ex vivo study was to compare the cleaning performance of three commercially available orthodontic cleaners on polymethyl methacrylate (PMMA) test specimens covered with biofilm. METHODS: Twenty subjects wore an individually manufactured vacuum-formed maxillary splint with four integrated PMMA test specimens for 7 days. The four test specimens were located on the buccal surfaces of the maxillary molars. After a 7-day wearing period, the PMMA test specimens colonized by biofilm were divided into two halves. One half was placed in 150 ml of tap water or in 150 ml of cleaning solution of the cleaners Retainer Brite® (Dentsply International Raintree Essix, Sarasota, FL, USA), Kukis® Xpress (Reckitt Benckiser, Heidelberg, Germany) or Dontodent (Propack, Heidelberg, Germany) while the other half remained uncleaned. The modified o­phthaldialdehyde (OPA) method was used to determine the amount of protein on both halves of the test specimens. The difference was tested for significance as a measure of the cleaning effect using a paired sample t­test. RESULTS: The cleaning performance of the three orthodontic cleaners was higher than the cleaning performance of tap water (mean 25.9 ± 6.5%). While Retainer Brite® (mean 54.5 ± 7.1%) removed significantly more biofilm than Dontodent (mean 41.5 ± 9.2%, p < 0.001) and Kukis® Xpress (mean 39.9 ± 11.5%, p < 0.001), there was no significant difference in the cleaning performance between Kukis® Xpress and Dontodent (p = 1). CONCLUSION: Seven-day-old biofilm is only removed partially by the investigated orthodontic cleaners, so that they are not suitable as the only measure for removing established biofilms.

The association between molar incisor hypomineralization and oral health-related quality of life: a cross-sectional study.

OBJECTIVES: We aimed to assess the association between molar incisor hypomineralization (MIH) and the oral health-related quality of life (OHRQoL) in a group of 7- to 14-year-old children in Berlin, Germany. MATERIALS AND METHODS: The cross-sectional study consisted of a consecutive sample of 317 children, aged 7-14 years (49% girls, 51% boys; mean age, 8.71). Data were collected between June 2018 and December 2019. MIH was diagnosed using the criteria of the European Academy of Paediatric Dentistry. OHRQoL was assessed using the German 19-item version of the Child Oral Health Impact Profile (COHIP-G19). Differences in COHIP-19 summary scores between controls without MIH and MIH patients and with regards to MIH severity were tested for statistical significance using t test and analysis of variance (ANOVA), respectively. RESULTS: Data were obtained for 217 untreated MIH patients and 100 controls. OHRQoL of MIH patients was significantly more impaired than of controls indicated by COHIP-19 mean scores (60.9 ± 10.7 vs. 67.9 ± 7.8; p < 0.001). Patients with severe MIH (59.6 ± 11.0) reported significantly worse OHRQoL than patients with mild MIH (63.6 ± 9.1; p = 0.013). CONCLUSIONS: MIH has a significant negative impact on the children's OHRQoL. Patients with severe MIH experience a greater negative impact on OHRQoL than those diagnosed with mild MIH. CLINICAL SIGNIFICANCE: MIH is one of the major dental problems of our time; pediatric dentists should be aware of its impact on the OHRQoL of the patient.

Elution study of acrylic monomers from orthodontic materials using high performance liquid chromatography (HPLC).

PURPOSE: Main goal of the study was the identification and quantitative analysis of monomer elution from materials commonly used in fixed orthodontic therapy. Studies have shown severe health effects of monomers including cytotoxic, allergenic or mutagenic potential and endocrine changes. This in vitro study focusses primarily on five resins which are usually processed intraorally and remain in the oral cavity long-term. METHODS: We tested the elution of monomers from specimens (7.5 mmâ€¯× 1.5 mm) immersed in artificial saliva at body temperature (37 °C) for 30 min to 5 weeks. The used method is in accordance with DIN EN ISO 10993-13. The five tested materials were BrackFix® (Voco GmbH, Cuxhaven, Germany), Triad®Gel (DeguDent GmbH, Hanau, Germany), and Transbond™ XT, LR and Plus (3M Unitek, Monrovia, CA, USA). All aliquots were analyzed using high performance liquid chromatography (HPLC). Data were statistically analyzed. RESULTS: All five analyzed materials eluted substances over a period of 5 weeks. Identified substances included bisphenol A (BPA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA). BPA eluted from Transbond™ Plus, XT, LR and BrackFix®. The cumulated mean values after 35 days ranged from 16.04 to 64.83 ppm, depending on the material. TEGDMA eluted with a mean of 688.61 ppm from Transbond™ LR. UDMA with a mean of 1682.00 ppm from Triad®Gel. For each material the highest concentrations of all these substances were found in the first elution period. Other substances that were not equivocally identified or of low concentration also eluted. CONCLUSION: Using the described method, it is possible to qualitatively and quantitatively determine the in vitro elution of monomers from orthodontic materials. The concentrations of the substances identified were below the current maximum recommended intake. However, a cumulative effect and low-dose effects should be considered for both patients and dental professionals, especially for young patients. Measures to reduce exposure patients and practitioners are suggested.

Quality of orthodontic care-A multicenter cohort study in Germany : Part 1: Evaluation of effectiveness of orthodontic treatments and predictive factors.

AIMS: Orthodontic care and its effectiveness have increasingly become the focus of political and public attention in the recent past. Therefore, this multicenter cohort study aimed to report about the effectiveness of orthodontic treatments in Germany and to identify potential influencing factors. METHODS: A total of 586 patients from seven German study centers were screened for this cohort study, of which 361 patients were recruited at the end of their orthodontic treatment. Of these, 26 patients had missing study models and/or missing treatment information. Thus, 335 participants were included. The severity of malocclusion was rated using the Peer Assessment Rating (PAR) Index at baseline (T0) retrospectively and-prospectively-after the retention period (T1). Practitioner-, treatment- and patient-related information were analyzed in order to detect potential predictive factors for treatment effectiveness. RESULTS: Study participants (202 female and 133 male) were on average 14.8 (standard deviation [SD] ± 6.1) years old at start of active treatment. Average PAR score at T0 was 25.96 (SD ± 10.75) and mean posttreatment PAR score was 3.67 (SD ± 2.98) at T1. An average decrease of total PAR score by 22.30 points (SD ± 10.73) or 83.54% (SD ± 14.58; p < 0.001) was detected. Furthermore, 164 treatments (49.1%) were categorized as 'greatly improved' but only 3 treatments (0.9%) as 'worse or no different'; 81.5% of all cases finished with a high-quality treatment outcome (≤5 PAR points at T1). Logistic regression analyses detected staff experience as a significant predictive factor for high-quality results (odds ratio 1.27, p = 0.001, 95% confidence interval 1.11-1.46). CONCLUSION: The improvement rate among this selected German cohort indicated an overall very good standard of orthodontic treatment. Staff experience proved to be a predictive factor for high-quality results.

Efficacy of cleaning tablets for removable orthodontic appliances: an in vivo pilot study.

OBJECTIVES: The purpose of this study was to test the cleaning effect of three commercially available effervescent tablet products on acrylic resin surfaces compared to water as control medium. METHODS: A total of 20 volunteers were instructed to wear a vacuum-formed maxillary splint continuously for 96 h. Each splint incorporated four resin discs in the palate area. Each of these PMMA (polymethyl methacrylate) discs was split into two specimens which were analyzed upon removing the splint after the 4-day period. One specimen per disc was analyzed uncleaned and one after cleaning, using one of the investigated tablet products according to the manufacturer's recommendations or water as control medium. The outcomes of cleaning were evaluated with the modified ortho-phthaldialdehyde (OPA) method by determining the amounts of surface protein. RESULTS: Significant differences in relative (%) protein removal were noted between all three tablet products and water, and fittydent super® was significantly more effective in removing biofilm than Kukis®. No significant differences were observed between fittydent super® and NitrAdine® Ortho&Junior™ or NitrAdine® Ortho&Junior™ and Kukis®. CONCLUSION: The modified OPA method proved to be successful in examining protein-containing contaminations on the specimens, and the effervescent products tested were more effective than pure water in removing contaminants from orthodontic appliances. These results are, however, confined to soft plaque not older than 4 days.

Shear bond strength of different adhesives tested in accordance with DIN 13990-1/-2 and using various methods of enamel conditioning.

OBJECTIVES: The purpose of this work was to analyze the shear bond strength (SBS) of different adhesives for orthodontic brackets in accordance with DIN 13990-1/-2, also taking into consideration potential effects arising from different scenarios of enamel conditioning and specimen storage. MATERIALS AND METHODS: A total of 390 experiments were performed, with groups of 10 specimens subjected to identical treatments. Three adhesives were tested: Transbond™ XT (3M Unitek, Monrovia, USA), Beauty Ortho Bond (Shofu, Kyoto, Japan), and Fuji Ortho LC (GC Europe, Leuven, Belgium). SBS was evaluated separately at the bracket-adhesive and adhesive-enamel interfaces, as well as the total (enamel-adhesive-bracket) interface. The brackets were metal brackets for upper right central incisors (Discovery® from Dentaurum, Ispringen, Germany). A universal testing machine (Zwick Z010, Ulm, Germany) was used for testing the SBS after 15 min, or after storage in distilled water at 37 °C for 24 h, or after 24 h followed by 500 thermocycles alternating between 5 and 55 °C. RESULTS: Transbond™ XT produced the highest levels of SBS. The least favorable performance was observed with Fuji Ortho LC after enamel conditioning with 10 % polyacrylic acid. Thermocycling did not have a significant influence. CONCLUSION: Transbond™ XT and Beauty Ortho Bond (but not Fuji Ortho LC) yielded levels of SBS adequate for clinical application (≥ 7 MPa).

Microdamage in the alveolar process of rat maxillae after orthodontic tooth movement.

OBJECTIVE: Playing a decisive role in bone remodeling, microdamage was recently associated with orthodontic tooth movement in pigs. The present study was conducted to evaluate microdamage and its potential association with orthodontic tooth movement in the alveolar process of rat maxillae. MATERIAL AND METHODS: The upper right molars of 24 male Wistar rats (10 weeks old) were splinted and loaded against the (likewise splinted) upper incisors with 25 cN using a Nitinol coil spring. Four groups of 6 animals were treated in this fashion for 1, 2, 4, or 7 days. The upper left quadrants served as controls. The maxillae were halved, gently prepared, and stained en bloc with basic fuchsin. After embedding in resin, 80-µm-thick parasagittal sections were ground parallel to the mesial root of the first molar. These were used to assess microdamage under transmitted and epifluorescent light, also counting and measuring the length of microcracks. Differences between the loaded and unloaded side and between mesial and distal were checked using a Wilcoxon test and were considered significant at ≤ 0.05. RESULTS: Microdamage (in the form of diffuse damage and microcracks) was observed in both the loaded and control jaw halves, as well as on the mesial and distal sides in all four groups. Microcracks averaged 30-100 µm in length and 0.3-1.7/mm(2) in density. While they were more prevalent in the loaded than the control jaw halves, this difference was not statistically significant. CONCLUSION: The alveolar process of rat maxillae is characterized by microdamage (in the form of microcracks and diffuse damage) regardless of whether and for how long orthodontic loading has taken place. Within the limitations of this experimental study, our results do not confirm previous findings of significantly higher prevalence on the pressure side on the first day after initiating orthodontic tooth movement.

Bone condition of the maxillary zygomatic process prior to orthodontic anchorage plate fixation.

OBJECTIVES: The clinical success of orthodontic miniplates depends on the stability of the miniscrews used for fixation. For good stability, it is essential that the application site provides enough bone of good quality. This study was performed to analyze the amount of bone available for orthodontic miniplates in the zygomatic process of the maxilla. METHODS: We examined 51 dental CT scans (Somatom Plus 4; Siemens, Erlangen, Germany) obtained from 51 fully dentate adult patients (mean age 24.0 ± 8.1 years; 27 male and 24 female) prior to third molar surgery. The amount of bone in the zygomatic process region at the level of the first molar root tips and at several other cranial levels as far as 15 mm from the root tips was measured RESULTS: Bone thickness at the root tip level averaged 4.1 ± 1.0 mm; the lowest value measured at this level in any of the patients was 2.7 mm. Bone thickness averaged 8.3 ± 1.0 mm at 15 mm cranial to the root tips; 6.9 mm was the lowest value. CONCLUSION: The zygomatic process appears to provide sufficient bone to accommodate screws for miniplate fixation. While some patients may possess a borderline amount of bone at more caudal levels, lack of volume is not a problem near the zygomatic bone.

Histomorphometry in antigen-induced arthritis of the rabbit temporomandibular joint.

BACKGROUND: Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) can cause severe growth disturbances of the craniomandibular system. Antigen-induced arthritis (AIA) of the rabbit TMJ is simulating the inflammatory process of the TMJ in JIA. The aim of this study was to investigate the effect of a systemic administration of the tumor necrosis factor-alpha (TNF-α) antagonist etanercept on AIA in rabbits by means of three different histological staining methods. METHODS: After sensitization, a bilateral arthritis of the TMJ was induced and maintained by repeated intra-articular administrations of ovalbumin in 12 New Zealand white rabbits aged 10 weeks. From the 13th week of age, 6 of the 12 rabbits received weekly subcutaneous injections of etanercept, and the other 6 animals remained without therapy. Another 6 animals served as controls, receiving no treatment or intra-articular injections at all. After euthanasia at the age of 22 weeks, all TMJs were retrieved en bloc. Sagittal sections were cut and stained with hematoxylin-eosin (H-E), Safranin-O for the evaluation of the Mankin score, and tartrate-resistant acid phosphatase (TRAP). RESULTS: In the arthritis group, a chronic inflammation with degeneration of the articular cartilage was visible. In the etanercept group, the signs of cartilage degeneration were significantly reduced but present. In contrast, the joints in the control group were inconspicuous. A strong correlation between the Mankin score and TRAP-positive cells could be found. CONCLUSIONS: Antigen-induced arthritis causes severe damage in the TMJ of young rabbits. An improvement seems to be achievable by a systemic administration of etanercept.

Demineralization adjacent to orthodontic brackets after application of conventional and self-etching primer systems.

OBJECTIVES: The goal of this work was to compare the demineralization of enamel associated with two different self-etching primers and traditional acid etching. MATERIALS AND METHODS: A total of 15 volunteers (23-32 years, 8 male and 7 female) were provided with a removable archwire/resin appliance to be worn 20 h/day for 28 days. The device was attached to the mandibular posterior teeth and included samples of human enamel (from extracted third molars) located in both posterior vestibules. Both sides featured the same distribution of samples, including one untreated control sample (group A) and three samples with brackets (Victory™ APC II) bonded to their surface after conditioning with a self-etching non-fluoride primer (iBond™ Gluma® Inside; group B), a self-etching fluoride-releasing primer (Transbond™ Plus; group C), or traditional acid-etching with 35% phosphoric acid and Transbond™ XT (group D). Mineral loss was assessed extraorally under standardized conditions using quantitative light-induced fluorescence (QLF) with a specialized camera system (Inspektor Pro). Results were expressed as relative fluorescence loss (ΔF in %). A baseline measurement (T0) was taken before the appliance was first inserted but with the brackets already bonded. Fluorescence loss was analyzed after 3 (T1), 7 (T2), 14 (T3), and 28 days (T4) and compared to the baseline loss (T0) for each of the four study groups (A to D). Kruskal-Wallis and Mann-Whitney U tests were used to compare the results for statistical significance. RESULTS: The lowest percentages of fluorescence loss both at baseline and during the follow-up assessments was found in group C. While all three experimental groups (B, C, D) presented total decreases in fluorescence loss after 28 days, indicating remineralization, the decrease in group C was the largest. The Kruskal-Wallis test yielded no significant differences between the three groups other than a significantly lower percentage of fluorescence loss in group C than in group D during the last assessment (T4). The untreated samples of control enamel (group A) revealed increasing percentages of fluorescence loss over the entire study period. CONCLUSION: Use of the self-etching primers (groups B and C) was not associated with patterns of enamel demineralization different from those noted after traditional etching with phosphoric acid (group D). The only significant difference we observed was between the self-etching fluoride-releasing primer (group C) and traditional etching (group D) at the final assessment (T4). Thus, the fluoride-releasing system Transbond™ Plus was advantageous.

Assessing bone volume for orthodontic miniplate fixation below the maxillary frontal process.

OBJECTIVES: The maxillary bone below the frontal process is used for orthodontic anchorage; indications have included skeletally anchored protraction of the maxilla for treating Class III malocclusions or the intrusion of teeth in patients with a deep bite. This study was conducted to assess the condition of bone before cortically implanting miniplates in that area of the maxilla. PATIENTS AND METHODS: A total of 51 thin-sliced computed tomography scans of 51 fully-dentate adult patients (mean age 24.0 ± 8.1 years; 27 men and 24 women) obtained prior to third-molar osteotomy were evaluated. Study parameters included total bone thickness, thickness of the facial cortical plate, and width of the nasal maxillary buttress. All these parameters were measured at different vertical levels. RESULTS: The bone volume adjacent to the piriform aperture was most pronounced at the basal level and decreased progressively toward more cranial levels. The basal bone structure had a mean total thickness of 7.8 mm, facial cortical plate thickness of 1.9 mm, and nasal maxillary buttress width of 9.2 mm. At 16 mm cranial to the aperture base, these values fell to 5.6 mm, 1.3 mm, and 5.8 mm, respectively. CONCLUSION: These bone measurements suggest that screws 7 mm in length can be inserted at the base level of the piriform aperture and screws 5 mm long at the cranial end of the bone.

Periodontal disease in patients with ankylosing spondylitis.

OBJECTIVE: Ankylosing spondylitis (AS) and periodontal disease (PD) are characterised by dysregulation of the host inflammatory response, resulting in soft and hard connective tissue destruction. AS has been related to other inflammatory diseases, however, there is a paucity of data on whether AS is associated with inflammatory PD. METHODS: The association between AS and PD was examined in 48 patients with AS and 48 healthy controls, matched for age and gender. AS was diagnosed according to the modified New York criteria. Periodontal examination included probing pocket depth (PPD), clinical attachment loss (CAL), plaque index (PI) and bleeding on probing (BOP). Potential risk factors of PD such as smoking, low education, alcohol consumption, body mass index (BMI), as well as chronic diseases associated with PD and AS were assessed through questionnaires. RESULTS: In stepwise logistic regression, including AS status, age, gender, education, smoking, alcohol consumption and BMI, only AS status, age and education remained significant predictors of PD. Patients with AS had significant 6.81-fold increased odds (95% CI 1.96 to 23.67) of PD (defined as mean attachment loss >3 mm) compared to controls. The strength of the association was attenuated but remained statistically significant after further adjustment for plaque accumulation (odds ratio (OR) 5.48, 95% CI 1.37 to 22.00). CONCLUSIONS: The present study shows that patients with AS have a significantly higher risk of PD, strongly suggesting the need for close collaboration between rheumatologists, periodontists and dental hygienists when treating patients with AS.

Applications of three-dimensionally scanned models in orthodontics.

The purpose of this study was to investigate clinical applications of the three-dimensional reverse engineering technologies for the analysis of orthodontic models. The measuring accuracy and the process of the 3D model scanning technique were evaluated with respect to linear, surface and volumetric parameters. Orthodontically induced dentoalveolar changes, which have been traditionally evaluated by cephalometric analysis, were assessed by the registration function of Rapidform 2002, a 3D-reverse modeling software in scanned maxillary casts. Three-dimensional digital models are valuable alternatives to conventional casts for model analysis and also yield information which could previously be gathered only by cephalometric superimposition.

SureSmile--CAD/CAM system for orthodontic treatment planning, simulation and fabrication of customized archwires.

SureSmile is an all-digital system which uses new 3-D imaging and computer techniques for diagnostics and treatment planning and uses robotics to customize fixed orthodontic appliances. Treatment can be simulated in advance and different treatment strategies can be visualized; this allows detailed treatment planning. The application of CAD/CAM aims at improving reproducibility, efficiency, and quality of orthodontic treatment.

Clinical measurement of force systems upon activation of transpalatal arch in the treatment of unilateral crossbite.

OBJECTIVES: in this study, forces and moments acting on the molars were theoretically determined by means of small-deflection analysis when an asymmetric third-order activation of the TPA was carried out. MATERIALS AND METHODS: the transpalatal arch (TPA) is used to correct unilateral crossbites through the application of buccal root torque to the anchorage molar and lingual root torque to the contralateral molar in crossbite, combined with expansion. Unfortunately, the complex force systems created at the molars upon activation of the TPA cannot be easily estimated. RESULTS: our computations revealed that the vertical forces developed on the molars when both ends of the TPA are inserted into the lingual sheaths (two-couple system) is four-times greater than those when only one end is tied to the lingual sheath as a single-point contact (one-couple system). CONCLUSIONS: we propose a method of clinical estimation of the force system in a two-couple system by directly measuring the vertical force produced by the one-couple system.

Experimental evaluation of initial tooth displacement, center of resistance, and center of rotation under the influence of an orthodontic force.

The purpose of this study was to determine the location of the center of resistance and the center of rotation of the maxillary central incisors under the influence of a single simple force and to investigate related geometric parameters of the teeth and the surrounding periodontal tissues. By measuring the initial displacement of the central incisors with a magnetic sensing system, the location of the center of resistance and the centers of rotation associated with various forces were determined in 3 human subjects. The results show that the location of the center of resistance of the maxillary central incisor depends on the palatal bone level and is at approximately two-thirds of the palatal alveolar bone height, measured from the root apex. A greater moment-to-force ratio is needed for any controlled movement of the maxillary incisors during retraction in patients with reduced palatal alveolar bone height. This study suggests a method for estimating the location of the center of resistance of a tooth.

Clinical evaluation of a new technique for interdental enamel reduction.

In orthodontics, reduction of tooth-size by grinding interproximal surfaces (stripping) of teeth is a common procedure. In order to achieve perfectly smooth surfaces, clinicians have carefully tested various methods and progressively improved this therapeutic procedure. In this in-vivo study we used scanning electron microscopy (SEM) to evaluate the morphologic effect of a 3-step technique using an oscillating perforated diamond-coated disc for enamel reduction and 2 Sof-Lex XT discs for polishing. This technique was applied in 32 patients with an average age of 15.5 years. A total of 296 interproximal surfaces was treated and replicas were produced for scanning electron microscopy evaluation. The scanning electron microscopy investigations demonstrated that more than 90% of the reproximated surfaces were very well or well polished, resulting in polished enamel surfaces smoother than untreated enamel. This technique proved to be clinically expedient as it finished each interproximal surface within about 2.2 minutes. At the same time, it was demonstrated to be safe and comfortable for the patient, eliminating the need for lip or cheek protectors and making injuries unlikely.

Ultrasonographic measurement of tongue movement during swallowing.

Previous ultrasonographic studies on tongue functions were limited by the possibility of artifacts caused by movement of the submental area during function. Consequently, tongue movements were misinterpreted. A dynamic tongue imaging technique, the cushion-scanning technique, was used to overcome this problem. Later, swallowing was investigated and divided into five phases using cushion-scanning technique-aided M-mode ultrasonograms. In this study, cushion-scanning technique in combination with the B-mode and M-mode ultrasonography was applied to investigate and measure the tongue movement during swallowing in 55 normal persons. The average duration, range of motion and speed of swallowing were found to be 2.43 s, 24.06 mm, and 10.34 mm/s, respectively. The computer-aided B-mode plus M-mode ultrasonography in combination with the cushion-scanning technique is a valuable tool for study of tongue functions.