Journal of the World Federation of Orthodontists最新文献

Background

The aim of this in vivo study was to quantitatively evaluate pain after rapid maxillary expansion (RME) in young rats by analyzing the activation of nociception-related structures, that is, the caudalis, interpolaris, and oralis subnuclei, according to the Fos expression.

Methods

A total of 65 Wistar rats were assigned to three groups: control group (n = 15) with no treatment, positive control group (n = 25), and experimental group (n = 25) with RME. The experimental animals were euthanized at 6, 12, 24, 48, and 72 hours after RME, and the brain was later carefully collected. Coronal sections through the spinal trigeminal caudalis, spinal trigeminal interpolaris, and spinal trigeminal oralis were cut (thickness of 40 µm) on a cryostat and processed for Fos immunohistochemistry. Images from the sections were captured under light microscopy, and ImageJ software was used to count Fos-like immunoreactive neurons. The Analysis of variance (ANOVA) and Tukey test were used for statistical analysis, and the significance level was set at 5%.

Results

RME induced incisor distalization and opening of the midpalatal suture, as well as neuronal activation of the spinal trigeminal nucleus. The experimental group demonstrated significantly more Fos-positive neurons in subnuclei caudalis and subnuclei interpolaris 6 hours after the maxillary expansion. The Fos immunoreactivity significantly decreased at 12 hours and increased again at 24 and 48 hours (P < 0.001).

Conclusions

The RME increases the neural activation of brain regions involved in the nociception region, as determined by the Fos expression. The most intense Fos-like immunoreactive expression was detected in the brain 6 hours after the start of the palatal expansion.

Background

An adhesive with both proper mechanical and antimicrobial properties seems to be beneficial. We aimed to investigate the effect of zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles (NPs) on bond strength and microleakage of two different fixed retainer adhesives.

Methods

In this in vitro experimental study, 168 extracted human incisors were randomly divided into six groups of 28 (eight double-tooth specimens for the bond strength test and 12 specimens for the microleakage test). In three groups: Transbond XT (3M Unitek, Monrovia, CA) without NPs, with 1% ZnO NPs and with 1% TiO2 NPs were applied. The other three groups included Ortho Connect Flow (GC orthodontics, Tokyo, Japan) composite with the same order to bond a 0.175-inch multistrand wire to the lingual surfaces of the teeth. The bond strength was measured using the Universal Testing Machine, and the adhesive remnant index was reported using a stereomicroscope (Nikon, SMZ800, Tokyo, Japan). The dye-penetration method was used to determine the microleakage.

Results

For bond strength, there was no significant difference among groups. For microleakage, there was no significant difference between GC and Transbond XT groups. However, in subgroups of Transbond XT, the addition of TiO₂ NPs increased the microleakage significantly in comparison with ZnO and control groups (P = 0.011). There was no significant statistical difference between the groups in terms of residual adhesives (P = 0.166).

Conclusions

Through the incorporation of 1% TiO₂ and ZnO NPs into the fixed retainer adhesive, the bond strength was maintained within the clinically acceptable range. The addition of TiO2 NPs to Transbond XT significantly increased the percentage of microleakage.

Background

This clinical trial aimed at studying the durability of an orthodontic sealant (Pro Seal) used on tooth surfaces for protection against white spot lesions.

Methods

A total of 35 patients (18 females, 17 males; 17.57 ± 1.36 years) were recruited. Eligibility criteria included healthy patients of both sexes (age > 14 years), absence of labial caries, absence of defective enamel, absence of extensive restorations, and optimum oral hygiene. The participants received a single application of Pro Seal on the bonded teeth. The sealant covered the labial enamel surrounding the brackets. Participants were recalled monthly after sealant application, during which sealant layers were evaluated using an ultraviolet lamp. The assessment was realized using an index similar to the adhesive remnant index (ARI).

Results

A total of 30 participants completed the trial. ARI values dropped significantly (P < 0.001) and reached <1.5 at T₁ on the index used. An ARI value of 2 was chosen as the threshold below which a tooth presented an insufficient sealant layer. The right and left sides of both jaws did not show any statistically significant difference (P > 0.05). ARI values of homolateral teeth revealed few statistically significant differences between upper and lower teeth. No statistically significant difference between the two sexes (P > 0.05) existed. No harm or disturbance was reported by any of the participants.

Conclusions

This study demonstrated that a single application of Pro Seal is effective for 4 weeks and should be renewed monthly. No interjaw, intrajaw, or intersex significant differences were found.

Digital technology is one of the major advancements during the past years that changed many aspects of our daily life. Medicine and dentistry were positively affected from the very first years of this digital evolution. Orthodontics is not an exception to this global digitization. Intraoral scanners, computer-aided design software, three-dimensional printers, and new materials were invented and introduced in dentistry and orthodontics during the last 20 years. The ability to include a small digital laboratory in the orthodontic office helped the creation of the in-house manufacturing concept. Continuously, the ability to design appliances that fit exactly to the teeth of the patient allowed the digital customization of almost every orthodontic appliance. Lately, the development of computer-aided design software called Ubrackets enabled the orthodontist to design and print customized orthodontic brackets in the orthodontic office. The designing workflow follows a specific protocol, which makes designing fast and easy. Three-dimensional printing of brackets can be performed using hybrid ceramic resin or zirconia slurry. Although some controversial studies exist, customized brackets have not been extensively studied despite that. A new term, “biological customization” is proposed, which takes into consideration the different biology of each patient, as opposed to teeth roots, bone turnover, and characteristics. Complete treatment customization should necessarily include mechanical and biological customization.

Intraoral scanning techniques, and the associated software, have revolutionized model acquisition, analysis, and virtual planning in orthodontics. Three-dimensional printing is the final aspect of this digital workflow, converting these virtual models and simulations of the tooth and occlusal movements into physical reality. This article provides an insight into how in-house three-dimensional printing is now a feasible and transformative reality for many orthodontic settings and how this empowers orthodontists to optimize their patient care.

Orthodontic tooth movement occurs in six degrees of freedom, which includes opening and closing spaces. Traditionally, opening and closing spaces are achieved with auxiliaries such as power chains or springs because all traditional bracket systems cannot achieve this tooth movement by themselves. The InBrace system has the capability to program tooth movement in all six degrees of freedom, including opening and closing spaces, through digital customization and its use of Programmed Non-Sliding Mechanics.

Clear aligners are the most debated infusion of technology into the orthodontic stratosphere and currently account for a sizable chunk of the orthodontic commercial market. Data indicate that a series of plastic aligners alone cannot resolve all the variants of malocclusion routinely treated by our specialty. Current literary consensus exists that the discrepancy between the predicted and actual clinical outcomes with clear aligner therapy (CAT) is around 50% or more, necessitating midcourse corrections, refinement, or additional aligners, or even a conversion to fixed appliances before the end of treatment. A practical panacea to improve the predictability of CAT is the addition of creative and customized adjuncts to CAT. This article, inspired by the “Golden Circle Model”, addresses questions such as the “WHY, HOW, and WHAT” of adjuncts used in combination with CAT and depicts an “inside out” approach (from WHY to WHAT) to present the rationale, stepwise clinical workflow, and the advantages of these adjuncts. The bootstrap, mini pin-supported mesialization or distalization, Yin-Yang attachments, Beneslider, Mesialslider, BMX Expander, and Computer-Aided Design (CAD) / Computer-Aided-Manufacturing (CAM)...based innovative appliance designs among others, are presented as adjuncts to CAT in this article. These adjuncts can either be used concomitantly with the aligners or planned as a separate phase of treatment before the commencement of the actual CAT, based on the type of tooth movement required and whether the planned tooth movement is indicated for a single tooth or a group of teeth. An astute clinician who wishes to expand the repertoire of malocclusions that can be successfully managed by CAT should judiciously plan the inclusion of such adjunct appliances in their aligner treatment planning.