Ivan Toshio Maruo

Effect of etching and light-curing time on the shear bond strength of a resin-modified glass ionomer cement

The aim of this study was to assess the influence of etching and light-curing time on the shear bond strength (SBS) and adhesive remnant index (ARI) of a resin-modified glass ionomer cement (RMGIC) upon debonding of orthodontic brackets. Sixty-eight bovine permanent incisors were obtained and embedded in acrylic resin. Edgewise metallic brackets were bonded to the teeth with Fuji Ortho LC RMGIC. The specimens were randomly assigned to 4 groups, using the following etching and light-curing times: G1: 10% polyacrylic acid and 40 s (control); G2: 37% phosphoric acid and 40 s; G3: 10% polyacrylic acid and 50 s; and G4: 37% phosphoric acid and 50 s. Shear test was performed at 0.5 mm/min and the ARI was assessed. G2 (3.6 ± 0.98 MPa) presented significantly higher (p<0.05) SBS than G1 (2.76 ± 0.86 MPa) and G4 (2.86 ± 0.68 MPa), and there was no statistically significant difference (p>0.05) between G2 and G3 (2.94 ± 0.67 MPa). ARI presented prevalence of scores 2 and 3 in all groups. RMGIC SBS enhanced with 37% phosphoric acid etching and 40 s light-curing time, but this did not occur when the light-curing time was increased, regardless of the acid used. RMGIC presented prevalence of failures at the adhesive/bracket interface.

Influence of Natural Bovine Enamel Roughness on Bond Strength after Etching

OBJECTIVE To determine and compare the longitudinal and transverse roughness parameters of the enamel surface of bovine teeth and evaluate the influence of these parameters on bond strength. MATERIALS AND METHODS Ninety bovine incisors were used. The surface roughness of enamel was measured with a profilometer. For each tooth, five readings were taken in the longitudinal plane and five were taken in the transverse plane of the long axis of the tooth in an area equal to the size of the bracket base. The metal brackets were bonded with Transbond XT, and bond strength was evaluated in a universal test machine. RESULTS There was a statistical correlation (P < .01) between the longitudinal and transverse roughness measurements. There was no correlation between roughness measurements (longitudinal and transverse) and bond strength (P > .05), nor was there a correlation between total roughness (longitudinal Ra and transverse Ra) and bond strength. The Students t-test showed that there was a statistically significant difference (P < .05) between longitudinal and transverse roughness. CONCLUSION The transverse roughness is greater than the longitudinal roughness, there is a strong correlation between longitudinal and transverse roughness, and there is no correlation between enamel roughness and bond strength.

Insertion torque, pull-out strength and cortical bone thickness in contact with orthodontic mini-implants at different insertion angles.

This study aimed to evaluate biomechanical behaviour of inclined orthodontic mini-implants by analyzing its insertion torque (IT), axial pull-out strength (APS), and cortical bone thickness in contact with mini-implant (CBTC). A total of 102 mini-implants were inserted at 90 degree, 60 degree, and 45 degree to the surface of synthetic bone. Peak IT was measured, and the mini-implants were aligned with the mechanical testing machine to record the APS. The cortical bone thickness in contact with each mini-implant was measured after the pull-out test and the data were subjected to statistical analyses. The 45 degree group had a significantly higher IT compared with the 90 degree group (P < 0.05). There was a statistically significant increase in the average of cortical bone thickness in CBTC across the three groups (P < 0.05). A negative correlation between the angulation and the CBTC (r = -0.95, P < 0.05) and a positive correlation between the APS and the CBTC were observed (r = 0.34, P < 0.05). Mini-implants that are inserted more inclined to the surface of the bone provide greater IT and an increased contact with the cortical bone. The greater the CBTC, the greater is the APS.

Treatment of an adult with several missing teeth and atrophic old mandibular first molar extraction sites

This report describes the orthodontic treatment of a woman, aged 34 years 2 months, with several missing teeth and atrophic mandibular first molar extraction sites. We had planned to close the spaces from the missing maxillary canines with mesial movement of the premolars and molars. In the mandibular arch, protraction of the second molars into first molar extraction sites and reduction of the mandibular incisor protrusion were performed. No miniscrews or bone plates were used. A modified helical loop was used, and it can be considered a simple and an efficient orthodontic method of closing the spaces without mesial or lingual tipping and rotation. Pleasing esthetic and functional results were achieved.

Orthodontic-prosthetic treatment of an adult with a severe Class III malocclusion.

This case report describes the treatment of a 37-year-old woman with multiple restored and missing teeth, a Class III subdivision malocclusion, and complete dental crossbite. Treatment options included orthognathic surgery and an orthodontic-prosthetic approach. The patient opted for nonsurgical treatment with space opening for prosthetic replacement of the first maxillary molars.

Orthodontic intrusion of maxillary incisors: a 3D finite element method study

Objective: In orthodontic treatment, intrusion movement of maxillary incisors is often necessary. Therefore, the objective of this investigation is to evaluate the initial distribution patterns and magnitude of compressive stress in the periodontal ligament (PDL) in a simulation of orthodontic intrusion of maxillary incisors, considering the points of force application. Methods: Anatomic 3D models reconstructed from cone-beam computed tomography scans were used to simulate maxillary incisors intrusion loading. The points of force application selected were: centered between central incisors brackets (LOAD 1); bilaterally between the brackets of central and lateral incisors (LOAD 2); bilaterally distal to the brackets of lateral incisors (LOAD 3); bilaterally 7 mm distal to the center of brackets of lateral incisors (LOAD 4). Results and Conclusions: Stress concentrated at the PDL apex region, irrespective of the point of orthodontic force application. The four load models showed distinct contour plots and compressive stress values over the midsagittal reference line. The contour plots of central and lateral incisors were not similar in the same load model. LOAD 3 resulted in more balanced compressive stress distribution.

Clinical challenges in treating a patient with deviated dental midlines and delayed root development of the mandibular left second premolar

This case report describes the treatment of a girl, aged 13.3 years, with a concave face and a Class I relationship on the right and Class III on the left at the first molars. The left canines were in full Class II occlusion. The overbite was excessive at 80%. The maxillary dental midline was deviated 2.0 mm to the right, and the mandibular dental midline was 3.0 mm on the opposite side with a 5-mm deviation between both arches. There was a -2-mm mandibular arch length discrepancy, but, considering the intrabony left second premolar with root-delayed development, the arch length discrepancy was -8 mm. The incisors were also retroclined. A nonextraction treatment plan was used. When space to the left of the intrabony second premolar was opened, the tooth erupted passively, and the root had a normal length. The esthetic results were functional and pleasing.

Valores Referenciais para Procedimentos Odontológicos (VRPO) em Ortodontia

INTRODUCTION: The cost of orthodontic treatment is a very important issue. The aim of this study was to analyze the current Indicative Values for Dental Procedures (IVDP) for orthodontic procedures. METHODS: Laws, dental entities papers and scientific literature were utilized. RESULTS: Laws are too general and only offer abstract parameters when define remunerations. Current IVDP vary in the same State, according to the consultant entity. Dental entities interpret that general clinicians can practice Corrective Orthodontics, but new scientific studies begin to question this understanding. The Brazilian Association of Orthodontics and Dentofacial Orthopedics (ABOR) suggests that IVDP for orthodontic specialty must be formulated. CONCLUSION: Current IVDP are not standardized and are below the correct values for orthodontic procedures, because they are the mean of general clinicians and orthodontists remunerations; and ABOR is legally and ethically supported to claim specific IVDP for orthodontic specialty.

Influence of Ortho Primer Morelli adhesion booster on orthodontic brackets shear bond strength

OBJECTIVE: This work aimed at assessing the bond strength (AS), the site of the flaw and the relation between them and Ortho Primer Morelli® (OPM) adhesion optimizer. METHODS: Sixty test specimens, made out of bovine permanent lower incisors, were divided into three groups: TXT Primer (control), in which a conventional adhesive system was applied (primer and paste); OPM, in which TXT primer was replaced by OPM; and TXT without Primer, in which only TXT paste was used. A shear force was applied at a speed of 0,5 mm/min. Failure site was assessed by the Remaining Adhesion Index (RAI). RESULTS: Kruskal-Wallis demonstrated that OPM (8.54 ± 1.86 MPa) presented a statistically higher AS (p 0.05) between TXT with or without Primer (6.42 ± 2.12 MPa). Regarding the RAI, the K test demonstrated that TXT Primer and OPM (prevailing scores 2 and 3) showed higher values (p 0.05). CONCLUSION: OPM increases AS and presents the same bond failure location if compared to a conventional adhesive system; the use of the TXT adhesive system paste only was shown to have the same AS if compared to conventional systems, except it does not allow to predict the adhesive failure site; there is no correlation between AS and bond failure location, regardless of the use of any adhesion optimizer.

Class II Division 2 subdivision left malocclusion associated with anterior deep overbite in an adult patient with temporomandibular disorder

ABSTRACT The orthodontic treatment of patients with chief complaint of temporomandibular disorders (TMD) presents doubtful prognosis, due to the poor correlation between malocclusions and TMDs. The present case report describes the treatment of an adult patient with Angle Class II Division 2 subdivision left malocclusion associated with anterior deep overbite and TMD. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO), as part of the requirements to obtain the title of BBO Diplomate.