Toru Deguchi

Analysis of pain level in cases treated with Invisalign aligner: comparison with fixed edgewise appliance therapy.

BackgroundThe aim of this study was to evaluate and compare the difference in the level of pain using the visual analog scale (VAS) between cases treated with the edgewise appliance and Invisalign. In addition, the cause of pain and discomfort in the Invisalign cases was identified.MethodsThe sample consisted of 145 cases for the edgewise group (EG; n = 55), Invisalign group (IG; n = 38), and edgewise and Invisalign group (EIG; n = 52). VAS scores were collected during the first three stages (first stage: 0 to 7 days, second stage: 14 to 21 days, and third stage: 28 to 35 days) and at the end of the treatment (overall VAS score). Evaluation of the cause of pain was categorized into three different types of problem (category 1: non-smoothed marginal ridge or missing materials, category 2: deformation of attachments, and Category 3: deformation of the tray). Statistical comparison of VAS scores between groups was performed by two-way analysis of variance.ResultsA significantly higher VAS score was observed at 3 and 4 days after, at 1, 2, and 3 days after, and at 2 and 3 days after in stages 1, 2, and 3, respectively, in EG compared to EIG and IG. A significant difference was observed in overall VAS scores between EG and IG in intensity of pain, number of days that pain lasted, and discomfort level. Only intensity of pain resulted in a significant difference between EG and EIG. Most of the causes of problem in the Invisalign cases were deformation of the tray.ConclusionsInvisalign may offer less pain compared to the edgewise appliance during the initial stages of treatment. In the use of Invisalign, deformation of tray must be carefully checked to avoid pain and discomfort for the patients.

Evaluation of Invisalign treatment effectiveness and efficiency compared with conventional fixed appliances using the Peer Assessment Rating index

Introduction: The purpose of this retrospective case‐control study was to compare the treatment effectiveness and efficiency of the Invisalign system with conventional fixed appliances in treating orthodontic patients with mild to moderate malocclusion in a graduate orthodontic clinic. Methods: Using the peer assessment rating (PAR) index, we evaluated pretreatment and posttreatment records of 48 Invisalign patients and 48 fixed appliances patients. The 2 groups of patients were controlled for general characteristics and initial severity of malocclusion. We analyzed treatment outcome, duration, and improvement between the Invisalign and fixed appliances groups. Results: The average pretreatment PAR scores (United Kingdom weighting) were 20.81 for Invisalign and 22.79 for fixed appliances (P = 1.0000). Posttreatment weighted PAR scores between Invisalign and fixed appliances were not statistically different (P = 0.7420). On average, the Invisalign patients finished 5.7 months faster than did those with fixed appliances (P = 0.0040). The weighted PAR score reduction with treatment was not statistically different between the Invisalign and fixed appliances groups (P = 0.4573). All patients in both groups had more than a 30% reduction in the PAR scores. Logistic regression analysis indicated that the odds of achieving “great improvement” in the Invisalign group were 0.329 times the odds of achieving “great improvement” in the fixed appliances group after controlling for age (P = 0.0150). Conclusions: Our data showed that both Invisalign and fixed appliances were able to improve the malocclusion. Invisalign patients finished treatment faster than did those with fixed appliances. However, it appears that Invisalign may not be as effective as fixed appliances in achieving “great improvement” in a malocclusion. This study might help clinicians to determine appropriate patients for Invisalign treatment. HighlightsBoth Invisalign and fixed appliances improved mild to moderate nonextraction patients.Invisalign finished treatment faster than fixed appliances.Fixed appliances improved malocclusion more effectively than Invisalign.

Outcome assessment of lingual and labial appliances compared with cephalometric analysis, peer assessment rating, and objective grading system in Angle Class II extraction cases

OBJECTIVEnTo validate our hypothesis that there would be significant differences in treatment outcomes, including cephalometric values, degree of root resorption, occlusal indices, and functional aspect, between cases treated with labial and lingual appliances.nnnMATERIALS AND METHODSnTwenty-four consecutively treated Class II cases with extractions and lingual appliance were compared with 25 matched cases treated with extraction and labial appliance. Orthodontic treatment outcomes were evaluated by cephalometric analysis, peer assessment rating, and an objective grading system (OGS). Additionally, functional analysis was also performed in both groups after orthodontic treatment. Statistical comparison was performed using the Wilcoxon signed rank test within the groups, and the Mann-Whitney U-test was used to compare between the labial and lingual groups.nnnRESULTSnThe only significant difference between the groups was that the interincisal angle was larger in the lingual group than in the labial group. OGS evaluation showed that control over root angulation was significantly worse in the lingual group than in the labial group. There was no significant difference between groups in the amount of root resorption or in functional evaluation.nnnCONCLUSIONSnGenerally, lingual appliances offer comparable treatment results to those obtained with labial appliances. However, care should be taken with lingual appliances because they are more prone to produce uprighted incisors and root angulation.

Interdisciplinary orthodontic treatment for a patient with generalized aggressive periodontitis: Assessment of IgG antibodies to identify type of periodontitis and correct timing of treatment

Aggressive periodontitis is a great challenge to clinicians when providing orthodontic treatment because of the potential for progression of periodontal disease. In this article, we report the successful comprehensive orthodontic treatment of bimaxillary protrusion and severe crowding in an adult with generalized aggressive periodontitis. A woman, aged 22xa0years 7xa0months, with a chief complaint of incisal crowding was diagnosed with a skeletal Class I malocclusion associated with severe anterior crowding, possibly worsened by generalized aggressive periodontitis. In addition to a periodontal examination, a blood IgG antibody titer analysis and microbiologic examination for periodontal pathogens were used to diagnose the type of periodontal disease and determine the proper timing to initiate orthodontic treatment. The total active treatment period was 28xa0months, followed by periodontal prostheses and regeneration therapy. Consequently, satisfactory facial profile, occlusion, and periodontal health were maintained for at least 36xa0months. These results indicate that efficient screening is important for providing successful orthodontic treatment in patients with advanced periodontal disease. This report also demonstrates the diagnostic importance of blood IgG antibody titer assays and microbiologic examinations to detect periodontal pathogens.

Implant therapy for a patient with Down syndrome and oral habits: A clinical report.

This clinical report describes prosthodontic therapy with an implant-supported partial fixed dental prosthesis for a patient with Down syndrome and concomitant oral habits, including tongue thrusting and thumb sucking.

CO2 low-level laser therapy has an early but not delayed pain effect during experimental tooth movement

OBJECTIVESnTo test the hypothesis that the use of low-level laser therapy (LLLT) reduces elevated pain by controlling the release of neurochemicals during orthodontic tooth movement.nnnSETTING AND SAMPLE POPULATIONnDepartment of Orthodontics and Dentofacial Orthopedics, Okayama University. Sixty-five Sprague Dawley rats were subjected to tooth movement and LLLT.nnnMATERIALS AND METHODSnAdult Sprague Dawley rats were used in this study. Groups included day 0 controls, irradiation only controls and with or without irradiation sacrificed at 1, 3, 5, 7 and 14xa0days after tooth movement (n=5 each, total n=65). Tooth movement was achieved by insertion of an elastic module between molar teeth. Immunohistochemistry for CD-11b, GFAP and c-fos in the brain stem was performed. Stains were quantified by constructing a three-dimensional image using IMARIS, and counted using NEURON TRACER and WinROOF software. Two-way ANOVA followed by a Tukeys post hoc test (P<.05) was used for statistical comparison between groups.nnnRESULTSnC-fos expression was significantly increased at one and three days after tooth movement. LLLT significantly diminished this increase in c-fos expression only at one day after tooth movement CD-b11 and GFAP expression also significantly increased after tooth movement. No significant change was observed for CD-11b and GFAP expression in the central nervous system upon LLLT.nnnCONCLUSIONnLow-level laser therapy may reduce early neurochemical markers but have no effect on delayed pain neurochemical markers after tooth movement.

Conditions and calibration to obtain comparable grey values between different clinical cone beam computed tomography scanners

OBJECTIVESnThe objective of the present study was to examine the grey value parameters and their magnitudes produced by CBCT and whether they are influenced by different scanners with various scanning conditions.nnnMETHODSnAn ATOM Max dental and diagnostic artificial head was scanned by two CBCT scanners (Planmeca and iCAT). Under full field of view with normal dose and ultralow-dose (ULD) conditions, the Planmeca scanner was examined for three scanning resolutions (200, 400, and 600 micron voxel sizes) and the iCAT scanner was tested for four scanning resolutions (200, 250, 300 and 400 micron voxel sizes). After 9 weeks, the artificial head was scanned again by the Planmeca scanner with the same scanning conditions. In addition, two hydroxyapatite phantoms (1220 and 1540u2009mgu2009cm-3) were adhered on the artificial head and scanned using normal and ULD scanning conditions of 400 micron voxel size with both scanners. The grey value histogram of each region, which is proportional to the bone mineral density (BMD) histogram, was utilized to determine grey value distribution parameters and compare scanners (ANOVA, pu2009<u20090.05).nnnRESULTSnThe different scanning conditions and the bilateral locations of the artificial head did not have significant effects on measurements of the grey value parameters (pu2009>u20090.436) with excellent repeatability. However, the iCAT scanner produced significantly different grey values from the Planmeca scanner (pu2009<u20090.001).nnnCONCLUSIONSnCBCT can assess BMD, while calibration of absolute measures is necessary to obtain comparable values between different scanners that are currently used to assess oral bone quantity and quality.

Effect of minocycline on induced glial activation by experimental tooth movement

INTRODUCTIONnOrthodontic tooth movement causes pain to a patient. Glial cells are nonneuronal cells in the central nervous system and are implicated in various types of pain. In this study, we assessed glial activation responses after experimental tooth movement using immunocytochemical detection of anti-CD11b (OX42) and glial fibrillary acidic protein immunoreactivity to illustrate the microglial and astrocytes response, respectively. In addition, the effect of minocycline in reducing pain during tooth movement was also investigated.nnnMETHODSnFifty-five Sprague Dawley rats with and without administration of minocycline after 1, 3, 5, 7, and 14xa0days (nxa0=xa05, for each) of tooth movement were used. Immunohistochemistry for microglia (OX42) and astrocyte (glial fibrillary acidic protein) were performed at the medullary dorsal horn (trigeminal subnucleus caudalis). Three-dimensional quantitative analysis was performed with a confocal fluorescence microscope and a software program.nnnRESULTSnThere was a significant increase in the OX42 and glial fibrillary acidic protein immunoreactivity in response to tooth movement in the medullary dorsal horn. Furthermore, systematic administration of minocycline, a selective inhibitor of microglial activation, significantly attenuated the nociceptive c-Fos expression in the medullary dorsal horn that was induced by experimental tooth movement.nnnCONCLUSIONSnThese data indicate the possible importance of microglial activation in the development of orthodontic pain. This is also the first report on the systematic application of minocycline.

Effect of guided bone regeneration on bone quality surrounding dental implants

Bone quality as well as its quantity at the implant interface is responsible for determining stability of the implant system. The objective of this study is to examine the nanoindentation based elastic modulus (E) at different bone regions adjacent to titanium dental implants with guided bone regeneration (GBR) treated with DBM and BMP-2 during different post-implantation periods. Six adult male beagle dogs were used to create circumferential defects with buccal bone removal at each implantation site of mandibles. The implant systems were randomly assigned to only GBR (control), GBR with demineralized bone matrix (DBM), and GBR with DBMu202f+u202frecombinant human bone morphogenetic protein-2 (rhBMP-2) (BMP) groups. Three animals were sacrificed at each 4 and 8u202fweeks of post-implantation healing periods. Following buccolingual dissection, the E values were assessed at the defects (Defect), interfacial bone tissue adjacent to the implant (Interface), and pre-existing bone tissue away from the implant (Pre-existing). The E values of BMP group had significantly higher than control and DBM groups for interface and defect regions at 4u202fweeks of post-implantation period and for the defect region at 8u202fweeks (pu202f<u202f0.043). DBM group had higher E values than control group only for the defect region at 4u202fweeks (pu202f<u202f0.001). The current results indicate that treatment of rhBMP-2 with GBR accelerates bone tissue mineralization for longer healing period because the GBR likely facilitates a microenvironment to provide more metabolites with open space of the defect region surrounding the implant.

Biosafety, stability, and osteogenic activity of novel implants made of Zr 70 Ni 16 Cu 6 Al 8 bulk metallic glass for biomedical application

Superior mechanical and chemical properties of Zr70Ni16Cu6Al8 bulk metallic glass (BMG) demonstrate its promise as a novel biomaterial for fabrication of implants. The aim of the present study was to validate mechanical, chemical, and biological properties of Zr70Ni16Cu6Al8 BMG through comparison with titanium (Ti). Our data indicated higher tensile strength, lower Youngs modulus, and reduced metal ion release of Zr70Ni16Cu6Al8 BMG compared with Ti. Biosafety of bone marrow mesenchymal cells on Zr70Ni16Cu6Al8 BMG was comparable to that of Ti. Next, screw-type implant prototypes made of Zr70Ni16Cu6Al8 BMG were fabricated and inserted into rat long bones. Zr70Ni16Cu6Al8 BMG implants indicated a higher removal-torque value and lower Periotest value compared with Ti implants. In addition, higher amounts of new bone formation and osseointegration were observed around Zr70Ni16Cu6Al8 BMG implants compared with Ti implants. Moreover, gene expression analysis displayed higher expression of osteoblast- and osteoclast-associated genes in the Zr70Ni16Cu6Al8 BMG group compared with the Ti group. Importantly, loading to implants upregulated bone formation, as well as osteoblast- and osteoclast-associated gene expression in the peri-implant area. No significant difference in concentrations of Ni, Al, Cu, and Zr in various organs was shown between in the Zr70Ni16Cu6Al8 BMG and Ti groups. Collectively, these findings suggest that Zr70Ni16Cu6Al8 BMG is suitable for fabricating novel implants with superior mechanical properties, biocompatibility, stability, and biosafety compared with Ti.nnnSTATEMENT OF SIGNIFICANCEnTitanium is widely used to fabricate orthopedic and dental implants. However, Titanium has disadvantages for biomedical applications in regard to strength, elasticity, and biosafety. Recently, we developed a novel hypoeutectic Zr70Ni16Cu6Al8 BMG, which has superior mechanical and chemical properties. However, the validity of Zr70Ni16Cu6Al8 BMG for biomedical application has not been cleared. The aim of the present study was to validate the mechanical, chemical, and biological properties of Zr70Ni16Cu6Al8 BMG for biomedical applications through comparison with Titanium. The present study clarifies that Zr70Ni16Cu6Al8 BMG has good mechanical properties, corrosion resistance, and osteogenic activity, which are necessary features for biomedical applications. The present study provides for the first time the superiority of Zr70Ni16Cu6Al8 BMG implants to Titanium implants for biomedical applications.