Eduardo Franzotti Sant’Anna

Reliability of upper airway linear, area, and volumetric measurements in cone-beam computed tomography.

INTRODUCTION Our objective was to assess the intraexaminer and interexaminer reliabilities of upper airway linear, area, and volumetric measurements in cone-beam computed tomography. METHODS Cone-beam computed tomography scans of 12 subjects were randomly selected from a pool of 132 orthodontic patients. An undergraduate student, an orthodontist, and a dental radiologist independently made linear, area, and volumetric measurements. Linear anteroposterior and transversal measurements, cross-sectional area, sagittal area, minimum axial area, and volume measurements were made. The intraclass correlation coefficient (ICC) was used to assess intraexaminer and interexaminer reliabilities, and measurement errors were assessed. Agreement was further assessed with the Bland-Altman method and 95% limits of agreement. RESULTS Overall, the ICC values indicated good reliability for the measurements assessed. The ICC values were greater than 0.9 (excellent) for 93% of intraexaminer and 73% of interexaminer assessments. Transversal width measurements and cross-sectional area at the level of the vallecula, however, had only moderate reliability (minimum ICC, 0.63), large 95% limits of agreement, and the greatest mean measurement errors (as high as 16% and 13% of the mean measurements, respectively). Linear anteroposterior measurements; cross-sectional areas at the levels of the palatal plane, soft palate, and tongue; and sagittal area and volume were reliable measurements, with a minimum ICC of 0.93 and more restricted limits of agreement. CONCLUSIONS Based on these results, airway assessments by examiners with different backgrounds might have reliable anteroposterior linear measurements; cross-sectional areas at the levels of the palatal plane, soft palate, and tongue; and sagittal area and volume. The unreliable measurements were linear width, cross-sectional area at the level of the vallecula, and minimum axial area.

Microbiological evaluation of elastomeric chains.

OBJECTIVES To evaluate in vitro the surface of elastomeric chains of different manufacturers to verify the presence of pathogenic microorganisms at the moment of unpacking and analyze a possible inhibitory effect of the elastomeric chain when exposed to microorganisms of the oral cavity, for example, Streptococcus mutans, Lactobacillus casei, and Candida albicans. MATERIALS AND METHODS Elastomeric chains from Ortho-Organizers Inc, 3M Unitek, and Dental Morelli were placed in petri plates with brain heart infusion agar medium and in sterile test tubes with brain heart infusion broth. The samples were incubated at 37 degrees C and analyzed at 24 hours, 48 hours, 3 days, and 7 days. In addition, elastomeric chains from the three manufacturers were placed in dishes, inoculated with microorganisms, incubated at 37 degrees C, and analyzed after 24 and 72 hours. RESULTS No microorganism growth was detected after all incubation periods. No inhibition zones were identified surrounding the elastomeric chain. CONCLUSIONS The results suggest that the fabrication of elastomeric chain is in accordance with biohazard concepts. However, careful manipulation is necessary to avoid colonization of pathogenic microorganisms since the composition of the elastomeric chains analyzed do not include antimicrobial agents.

Effect of autoclaving on the fracture torque of mini‐implants used for orthodontic anchorage

Objective To evaluate the influence of autoclave sterilization on the fracture torque of five commercially available mini‐implants used for orthodontic anchorage. Design In vitro laboratory study. Materials and methods Ten mini‐implants from each of five different manufacturers were submitted to one cycle of autoclave sterilization and tested, compared to their control groups – consisting of 10 as‐received mini‐implants each – to assess their fracture torque values. The mini‐implants, connected to a digital torque gauge perpendicularly positioned to the bone surface, were inserted into swine femoral cortical bone segments until their fracture. Outcome measures Maximum torque values. Statistical analysis A two‐way ANOVA to detect differences between implant products and the allocation group and one‐way ANOVA with the Tukeys honestly significant difference (HSD) post hoc test among autoclaved groups and among control groups separately to detect differences between manufacturers. Results The effect of the autoclaving process was not significant (P = 0·411). The manufacturer factor, however, was significant (P<0·001). The one‐way ANOVA with the Tukeys HSD post hoc test results showed statistically significant differences between control groups. Conclusion The autoclave sterilization of the mini‐implants tested in this study did not affect their resistance to fracture; however, the mini‐implants from different manufacturers presented with statistically significant differences in their resistance to fracture.

Cross-section dimensions and mechanical properties of esthetic orthodontic coated archwires.

INTRODUCTION There has been continuing interest in the development and use of esthetic and effective orthodontic archwires. The aims of this study were to evaluate the inner alloy core dimensions of 4 brands of as-received esthetic coated wires and their mechanical properties before and after 21 days of oral exposure, compared with conventional stainless steel and nickel titanium wires. METHODS Four groups (Ortho Organizers, Carlsbad, Calif; TP Orthodontics, LaPorte, Ind; Orthometric, Beijing, China; and Trianeiro, Rio Claro, São Paulo, Brazil) of orthodontic archwires were tested. Five properties were evaluated: inner wire dimensions, modulus of elasticity, modulus of resilience, maximum deflection force, and load deflection curve characteristics. Images of the transverse sections from the specimens were made with a stereoscope. The inner alloy core dimensions of each wire were measured by using Image Pro Plus software (version 4.5; Media Cybernetics, Silver Spring, Md). All specimens were tested in a universal testing machine in a 3-point bending test. RESULTS Coated wires of the Ortho Organizers and Trianeiro groups showed greater reductions in their inner alloy core dimensions and produced lower loading and unloading forces and lower modulus of elasticity, modulus of resilience, and maximum deflection force values than did their control wires. Inner alloy core dimensions and the mechanical behavior of coated wires practically did not differ from the control wires in the TP Orthodontics and Orthometric groups. CONCLUSIONS The reduction on the inner alloy core dimensions to compensate for the coating thickness seems to be the variable responsible for greater changes in the mechanical properties of esthetic coated wires.

Cytogenetic biomonitoring in children submitting to a complete set of radiographs for orthodontic planning.

OBJECTIVES To evaluate the DNA damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated buccal mucosa cells from children undergoing orthodontic radiographs. MATERIALS AND METHODS A total of 25 healthy children undergoing orthodontic therapy partook in a complete set of orthodontic radiographs (lateral cephalographic, posteroanterior cephalographic, panoramic, full periapical exam, and bitewing). The micronucleus test in the buccal exfoliated cells was applied. The paired-samples t-test and the Wilcoxon test were used to compare the frequencies of alterations before and after X-ray exposure. RESULTS We found no statistically significant differences (P > .05) between micronucleated buccal mucosa cells before and after exposure to radiation. However, radiation did cause other nuclear alterations closely related to cytotoxicity (P  =  .007). CONCLUSION According to the micronucleus test, the complete set of radiographs requested in the orthodontic planning may not be a factor that induces chromosomal damage, but it is able to promote cytotoxicity.

Impacted incisors associated with supernumerary teeth treated with a modified Haas appliance

Tooth impaction involves factors such as lack of space in the alveolar process, trauma, ankylosis, and mechanical barriers such as abnormal frenum, supernumerary teeth, tumors, and local cysts. When impaction occurs in the anterior region, esthetics are compromised. This report describes the successful approach to treatment for a young boy who had 2 supernumerary teeth associated with impaction of the left central and lateral permanent incisors. Treatment consisted of extracting the supernumerary teeth and performing maxillary expansion with a modified Haas appliance to guide the left central incisor into its appropriate position. The teeth erupted spontaneously after maxillary expansion and an increase in space. A fixed edgewise appliance was placed incrementally to correct the maxillary anterior tooth positions and finish the treatment. Adequate esthetics and function were achieved.

Asymmetric headgear for differential molar movement: a study using finite element analysis

Objective To compare the effects of four different asymmetric headgear systems. Design A mathematical method for three-dimensional data called finite element analysis. Setting The Orthodontic Department, the Federal University of Rio de Janeiro and the Metallurgical Engineering Department of the Fluminense Federal University. Methods Four systems of delivering an asymmetrical force to headgear were studied: using face-bow arms of different lengths, a symmetric face-bow with one of the arms bent outward in relation to the internal arch, a symmetric face-bow used in combination with a transpalatal arch activated to produce an asymmetric force, and a symmetric face-bow with the outer bow soldered to the inner bow on the side where a larger force will be applied. Results All four systems were effective in promoting asymmetric distal movement of the molars. However, the symmetrical face-bow with the outer bow soldered to the inner bow (system 4) could be used in asymmetric mechanics if the bows are soldered on the opposite side to the proposed distalization. Lateral and occlusal displacing forces were observed in all systems as well as tip-back and rotational movements. Conclusion The simulated computer model used in this investigation suggests that a face-bow with a symmetrically soldered joint and arms of equal lengths used in combination with a transpalatal arch is the best headgear option when asymmetric movement of upper molars is desired.

The effect of tooth bleaching on the enamel surface and the tensile force to debond orthodontic brackets

Objective The aim of this study was to evaluate the influence of successive tooth bleaching on the tensile force to debond orthodontic brackets and dental enamel. Design In vitro study. Settings Department of Orthodontics, Faculty of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Materials and methods Seventy-two human premolars were divided into three groups: Group 1 was not submitted to bleaching, Group 2 was subjected to one tooth bleaching (35% hydrogen peroxide enabled by LEDs) and Group 3 was subjected to two tooth bleachings interspersed by aging. Twenty teeth from each group were subjected to tensile test, failure pattern after debonding and evaluation of resin/enamel interface. Four teeth from each group were not submitted to tensile bond testing and had their external surfaces and internal structure analyzed by SEM and polarized light microscopy. Results The strength of the brackets decreased in Groups 2 and 3, but was not significant (P=0.635). In general, the failure pattern appeared at the resin/bracket interface or within the resin. The experimental groups showed an increase in slots and erosions on the surface of the enamel and were more pronounced in Group 3. There were no changes to the internal structure of the enamel. Conclusions The use of a 35% hydrogen peroxide in-office bleaching system, in vitro, seven days before bonding, does not significantly reduce the tensile force to debond orthodontic brackets, even after a second bleaching procedure. In most cases, debonding occurred at the adhesive/bracket interface or within the adhesive. Bleaching alters the enamel surface and the resin/enamel interface, but it does not influence bond strength.

Assessment of exogenous pigmentation in colourless elastic ligatures

Introduction The aim of this study was to evaluate colour alteration of transparent elastic ligatures submitted to exogenous pigmentation. Methods Forty test specimens were divided into eight groups corresponding to one commercial brand with five test specimens in each group. The test specimens were immersed into coffee and black tea solutions with the purpose of assessing colour alteration using a portable digital spectrophotometer (Vita Easyshade Compact). The surfaces of the ligatures under scanning electron microscope (SEM) at ×30, ×150 and ×20,000 magnification were evaluated with the purpose of observing the differences in porosity of the ligatures. The Kolmogorov–Smirnov test for normality was applied followed by the one-way analysis of variance (one-way ANOVA) and the level of significance adopted was 95%. Results All the groups showed modified initial colour that was perceptible to the human eye. The brand that showed greater colour alteration, in comparison with its initial colour, was the American® pearl elastic ligature and the ligatures that presented the smallest colour variation were the Ortho-Organizer®. The surface evaluations of the ligatures showed differences with regard to the topography evidencing more porosity in the ligatures that showed greater staining. Conclusion The group that changed colour significantly was the one that presented the highest porosity, and the brand that was the least altered was the one that showed the lowest porosity.

High-intensity laser application in Orthodontics

ABSTRACT Introduction: In dental practice, low-level laser therapy (LLLT) and high-intensity laser therapy (HILT) are mainly used for dental surgery and biostimulation therapy. Within the Orthodontic specialty, while LLLT has been widely used to treat pain associated with orthodontic movement, accelerate bone regeneration after rapid maxillary expansion, and enhance orthodontic tooth movement, HILT, in turn, has been seen as an alternative for addressing soft tissue complications associated to orthodontic treatment. Objective: The aim of this study is to discuss HILT applications in orthodontic treatment. Methods: This study describes the use of HILT in surgical treatments such as gingivectomy, ulotomy, ulectomy, fiberotomy, labial and lingual frenectomies, as well as hard tissue and other dental restorative materials applications. Conclusion: Despite the many applications for lasers in Orthodontics, they are still underused by Brazilian practitioners. However, it is quite likely that this demand will increase over the next years - following the trend in the USA, where laser therapies are more widely used.