In vitro evaluation of the influence of velocity on sliding resistance of stainless steel arch wires in a self-ligating orthodontic bracket

INTRODUCTION

Of the variables used by in vitro studies of resistance to sliding (RS) in orthodontics, sliding velocity (SV) of the wire is often the one farthest from its clinical counterpart. We investigated whether velocity influences the RS at values approximating the orthodontic movement.

METHODS

A SS self-ligating bracket with a NiTi clip was fixed onto a custom-made model. Different shaped orthodontic SS wires of four sizes and two types (round, 0.020″ and 0.022″; rectangular, 0.016″×0.022″ and 0.017″×0.025″) were tested using an Instron^® testing machine. Wires were pulled at four velocities (1×10^-2  mm/s, 1×10^-3  mm/s, 1×10^-4  mm/s, 1×10^-5  mm/s). Shapiro-Wilk test was used to evaluate the normal distribution of the data; two-way ANOVA was performed to compare means in the RS with wire characteristics and SV. Significance level was set at P<.05.

RESULTS

RS was higher for rectangular wires, and for those with larger diameters. Lower SV was associated with lower RS, with wire type and size having an interaction effect. The RS relatively to SV can be represented as: RS ∝ α[ln(SV)]+β, where α and β are constants.

CONCLUSIONS

At very low SV and low normal forces, SV influences the RS of SS archwires in orthodontic brackets, and the proportionality is logarithmic. Although respecting these parameters in vitro is challenging, quantitative evaluations of RS should be carried out at clinically relevant velocities if aiming at translational application in the clinical scenario.

Impact of scientific and technological advances

Advancements in research and technology are transforming our world. The dental profession is changing too, in the light of scientific discoveries that are advancing biological technology-from new biomaterials to unravelling the genetic make-up of the human being. As health professionals, we embrace a model of continuous quality improvement and lifelong learning. Our pedagogical approach to incorporating the plethora of scientific-technological advancements calls for us to shift our paradigm from emphasis on skill acquisition to knowledge application. The 2017 ADEE/ADEA workshop provided a forum to explore and discuss strategies to ensure faculty, students and, ultimately, patients are best positioned to exploit the opportunities that arise from integrating new technological advances and research outcomes. Participants discussed methods of incorporating the impact of new technologies and research findings into the education of our dental students. This report serves as a signpost of the way forward and how to promote incorporation of research and technology advances and lifelong learning into the dental education curriculum.

Effects of fluorotherapy on oral changes caused by a vegan diet

AIM

The aim of this paper was to investigate the effects of fluorotherapy on the oral health of subjects who had been following a vegan diet (lacking in meat and animal derivatives) for a long period of time (at least 1 year and 6 months).

METHODS

A preliminary study (t0) evaluated 50 subjects, all from northern Italy and aged 24-60 years (28 male and 22 female) who had been following a vegan diet for a minimum of 18 months to a maximum of 20 years, and compared them with a control group of 50 individuals following a Mediterranean diet. All vegan subjects showed oral changes such as white spots, lesions invisible to the naked eye and decreased salivary pH values (~5-6). In a second study (t1), the 50 vegan subjects were randomly divided into two subgroups of 25. Subgroup SG1 underwent fluorotherapy with sodium fluoride (Elmex fluoride gel® 1.25%) administered once daily for 1 year. Subgroup SG2 served as controls and did not receive fluorotherapy. The following parameters were recorded before the start of fluorotherapy and again after 1 year: salivary pH; Decayed, Missing, Filled teeth Index; presence and location of white spots and lesions not visible to the naked eye; Plaque Index, and Gingival Index.

RESULTS

In SG1, larger lesions became smaller in diameter and small lesions disappeared, a statistically significant improvement compared with SG2, despite the persistence of restricted eating habits and the oral hygiene conditions being similar to those at t0. Salivary pH showed no significant change in either subgroup.

CONCLUSION

Daily application of a topical 1.25% fluoride gel is effective in reducing the incidence of white spot lesions caused by a vegan diet.

Evaluation of the cephalometrics modification of growing Class II Division I patients after treatment with the PUL appliance: a pilot study

AIM

The aim of this preliminary study was to evaluate short-term dentoskeletal changes obtained with a functional appliance for Class II Division I malocclusions called propulsor universal light (PUL).

METHODS

Fifteen Class II Division 1 patients (10.6±1.2 years) were consecutively treated by one expert operator with PUL appliance and they were compared with a longitudinal group of Class II Division I untreated patients (9.9±1.9 years) matched for pubertal growth spurt stage and sex. Lateral cephalograms were taken before PUL therapy and at the end of treatment. The mean duration of treatment was 11.2±0.3 months; t-test or Mann-Whitney U-test was used (P <0.05).

RESULTS

Statistically significant reduction of the overjet, WITS and ANB was noticed in treated group as well as a significant improvement of CoGo and Ramus.

CONCLUSION

Class II Division I malocclusion in the short term was efficiently treated by PUL appliance with both skeletal and dentoalveolar changes.

Use of CBCT in the orthodontic diagnosis of a patient with pycnodysostosis

The pycnodysostosis is a genetically determined, autosomal recessive osteosclerosis, due to deficiency of cathepsin K. It is characterized by short stature, massive skull, hands and feet with short terminal phalanges, dysplastic nails. Oral and maxillofacial manifestations include hypoplasia of the mandible and maxillary sinus, obtuse mandibular gonial angle deciduous teeth and permanent impacts, or malposition, frequent overcrowding, periodontal lesions. Bone sclerosis is already detectable in X-rays during childhood, often present open fontanelles and sutures, wormian bones; frequent pathological fractures. This article presents the case of a male patient, Caucasian, age 9 years and 11 months suffer from pycnodysostosis, mutation of the gene in heterozygotes p.R241X, already followed at the Pediatric Endocrinology Clinic of the Spedali Civili of Brescia. After evaluation at the Department of Maxillofacial Surgery of the Spedali Civili of Brescia, for surgical reasons required a cone beam computed tomography (CBCT) scanner with NewTom 3G, was presented to our observation at the Department of Orthodontics of the Dental Clinic of the University of Brescia. CBCT findings including detailed information about the anatomy of the upper and lower jaw, dental elements, their relationship with the surrounding anatomical structures and the spatial position. The only radiographic examination currently available that obtains 3D images and the volume of the life-size area, without exposing patient to dose of radiation from a classic multi-layer CT is CBCT that, even through the 3D reconstructions with dedicated programs can make a correct diagnosis, prognosis and treatment in patients with maxillofacial dysmorphism. This examination allows to obtain images from around the skull that permit a complete orthodontic diagnosis, not only restricted to the area of surgical interest, taking into account the reports of the dental arches to each other and with surrounding structures.

Oral implications of the vegan diet: observational study

AIM

The aim of this study was to investigate oral changes in subjects who have assumed a vegan diet for a long time (at least 18 months), that is to say, a diet completely lacking in meat and animal derivatives.

METHODS

A sample of 15 subjects was analyzed, all from northern Italy and aged 24 to 60 year, composed of 11 men and 4 women who had been following a vegan diet for a minimum of 18 months to a maximum of 20 years. In parallel with the study sample, a control group (15 subjects) with the same criteria of age, sex, and place of origin all following an omnivorous diet was chosen. The sample answered a questionnaire that investigated their eating habits, the frequency with which they eat meals, the main foodstuffs assumed, oral hygiene habits, and any painful symptomatology of the teeth or more general problems in the oral cavity. The sample was then subject to objective examination in which the saliva pH was measured and the teeth were checked for demineralization of the enamel, white spots, and caries (using KaVo DIAGNOdent) with particular attention being paid to the localization of these lesions, and lastly, sounding was carried out to detect any osseous defects and periodontal pockets.

RESULTS

The study revealed greater incidence of demineralization and white spots in the vegan subjects compared to the omnivorous ones localized at the neck of the teeth and on the vestibular surfaces of dental elements (with the exception of the lower anterior group). The saliva pH, more acid in the omnivorous patients, ranged between four and six. Changes in oral conditions in both groups of subjects were observed.

CONCLUSION

In order to research into the cause-effect relationship of the vegan diet on the oral cavity effectively, the sample needs to be studied for a longer period of time and the results re-evaluated.

Cone beam computed tomography role in diagnosis and treatment of impacted canine patient's: a case report

A tooth is impacted when its apex is formed but does not erupt as expected during the physiological timeframe of eruption. The frequency with which the upper canine is impacted in the sample examined varies from 1% to 5% of the population in the second decade of life. The most frequent causes of inclusion of the upper canine are: lack of resorption or precocious loss of the root of the deciduous, agenesis of the lateral, an anomaly in its shape, lack of space in the arch, presence of a mechanical obstacle to the eruption, and lastly due to hereditary factors. When dental impaction is suspected, radiographic examination is indicated to evaluate the effect that the impacted element is having in the context of the osseous structure and to evaluate its relationships with adjacent teeth, the presence of mechanical obstacles, the placement of the inclusion and its orientation in space, how well developed the root is, and any anomalies in its shape. In addition to the classic orthopantomography (OPT), endoral radiography, teleradiography, can be used in order to obtain three-dimensional and life-size images, techniques of computed tomography (CT). In particular, cone beam CT, obtains this type of image using a radioactive dose comparable to that obtained summarizing the classic radiographic examinations requested by an orthodontist and moreover less that that administered when using classic multi-layer spiral CT medical equipment. This case report describes the diagnostic iter and orthodontic-surgical treatment of a patient with enclosure of the right upper canine.