Effects of SARPE and MISMARPE on correction of transverse maxillary deficiency: A preliminary comparative evaluation.

AIM: The present study was designed to compare, on cone-beam computed tomography imaging, the skeletal and dental effects of the SARPE (Surgically assisted rapid palatal expansion) and MISMARPE (Minimally Invasive Surgical and Miniscrew-Assisted Rapid Palatal Expansion) techniques. MATERIALS AND METHODS: The sample of adult patients with transverse maxillary deficiency (TMD) was divided into two groups, and scans were obtained preoperatively (T0) and immediately after completion of expansion (T1). The posterior and anterior linear transverse distances of the maxilla and the angulation of the maxillary first molars were evaluated. The data were entered into a generalized estimating equations model to verify the postoperative effects of the different techniques. RESULTS: None of the techniques caused any appreciable change in the angulation of the molars. The skeletal changes were similar, with significantly greater gains in the nasal fossa and intermaxillary distance when using the MISMARPE. CONCLUSION: The technique can be an effective and lower morbidity alternative to SARPE.

Low-level laser therapy (LLLT) improves alveolar bone healing in rats.

The main objective of the present study was to evaluate the effect of low-level laser therapy (LLLT) in enhancing bone healing in irradiated alveolus post-tooth extraction. Sixty male Wistar rats (180 ± 10 g) were used in the present study. The left maxillary first molars were extracted, and the alveolar region was irradiated by diode laser device (GaAlAs) immediately after extraction and for more 3-day daily applications. The animals were randomly assigned into two groups: control group (n = 30, with left maxillary molar extraction-CG) and experimental group (n = 30, with tooth extraction and low-level laser therapy applied to the dental alveolus for 42 s-EG). These groups were divided into subgroups (five rats per subgroup) according to the observation time point-1, 2, 3, 5, 7, and 10 days-post-tooth extraction. The maxillary bone was separated, and the specimens were stained with hematoxylin and eosin, Masson's trichrome, and picrosirius red and immunohistochemistry for RUNX-2. Parametric and nonparametric tests were used with a significance level of 5%. LLLT accelerated bone healing with mature collagen fiber bundles and early new bone formation. Histomorphometric analysis revealed an increase of osteoblast (RUNX-2) and osteoclast (TRAP) activity and in the area percentage of cancellous bone in the lased alveolus compared to the control group. This increase was statistically significant (p < 0.05). Application of LLLT with a GaAlAs diode laser device enhanced bone healing and mineralization on alveolar region.

Dimensional and morphologic characteristics of unilateral impacted maxillary central incisors.

INTRODUCTION: This cross-sectional study aimed to investigate the crown and root characteristics of impacted central incisors compared with spontaneously erupted contralateral incisors and the influence of etiologic and local factors on their dimensions. METHODS: Forty-five patients (22 boys, 23 girls) who underwent orthodontic treatment for unilateral impaction of maxillary central incisors were referred for cone-beam imaging. Dimensions of the impacted and contralateral incisors were assessed using Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). Paired t test and linear regression were used to compare the characteristics of the impacted and contralateral teeth. RESULTS: Contralateral and impacted central incisors showed statistically significant differences for root length (95% confidence interval [CI], 2.32-3.46; P <0.001), mesiodistal crown-root angulation (95% CI, 4.09-15.95; P = 0.001), and labiolingual crown-root angulation (95% CI, -18.69 to -4.70; P = 0.002). Etiologic factors did not alter the dimensions of incisors (95% CI, -1.17 to 0.76; P = 0.672). According to the multiple linear regression the independent variables associated with root length of contralateral and impacted incisors were sex (ß = -0.904; 95% CI, -1.62 to - 0.19; P = 0.014) and the presence of impaction (ß = -2.87; 95% CI, -3.67 to -2.07; P <0.001). CONCLUSIONS: Regardless of their etiology, the impacted incisors showed roots that were 2.89 mm shorter than the contralateral incisors and had greater angulation in the mesiodistal and labiolingual directions. Girls showed a reduction of 0.904 mm (7.6%) on the lengths of roots of both impacted and contralateral central incisors. The presence of impaction led to a reduction of 25% in incisor root lengths. Approximately 30% of the impacted teeth showed crown-root angulations >20° resulting in an increased distal and labial angulation of the root apical portion.

Comparison between traditional and alternative biocompatible welding techniques used in orthodontic devices.

OBJECTIVE: To compare the mechanical strength of joints made by conventional soldering with those made by alternative, more biocompatible, methods (spot, tungsten inert gas [TIG] and laser welding), and to compare the microstructural morphology of wires welded with these techniques. DESIGN: In vitro, laboratory study. METHODS: Forty stainless-steel wire segments with 0.8-mm diameter were joined by silver soldering, spot, laser and TIG welding. Ten specimens were produced for each one. Tensile strength test was performed 24 h after welding on the Emic DL2000™ universal testing machine, using a load cell of 1000 N with a crosshead speed of 10 mm/min. RESULTS: The highest tensile strength mean values were obtained with silver soldering (532 N), next were laser (420 N), spot (301 N) and TIG (296 N) welding. Statistically significant differences were observed between the groups; the Dunn post-hoc test revealed differences between laser and spot welding (p=0.046), laser and TIG (p = 0.016), spot and silver (p <0.001), and silver and TIG (p <0.001). CONCLUSION: Laser welding strength is high, and comparable to silver welding. Spot and TIG techniques present comparable and significantly lower strengths. The four methods presented resistance values compatible with orthodontic use. The microstructural morphology is different for each technique. The association between the mechanical performance and the microstructure evaluation shows that laser presented the highest quality joint.

Metal ion quantification in the saliva of patients with lingual arch appliances using silver solder, laser, or TIG welding.

OBJECTIVES: Quantify metal ion release in the saliva, considering that orthodontic appliances with soldered or welded parts may suffer corrosion and release metal ions into saliva, which can trigger adverse effects, such as hypersensitivity. METHODS: Sixty-four patients were distributed into four groups: G1 (control), G2 (silver-soldered lingual arch), G3 (laser-welded lingual arch), and G4 (TIG-welded lingual arch). Saliva samples were collected at four different points and were analyzed for ion release with ICP-MS. RESULTS: For Cr, Fe, Cu, and Sn ion concentrations among groups, there was no difference along collections and no statistically significant difference throughout collections for any group (P > 0.05, with release values between 3.3 and 4.2 µg/L for Cr, 201 and 314.8 µg/L for Fe, 23.1 and 40.7 µg/L for Cu, and 13 and 27.7 µg/L for Sn). For Ni, G4 showed an increased ion release at T2 (14.3 µg/L) and T4 (34.5 µg/L), values with an interaction effect (P < 0.001) comparing the groups and the points of collection. For Zn, Ag, and Cd ions there was no difference along the points in time (P > 0.05). For Zn ions, there was a statistic difference from G4 to G1 and G2 (P = 0.007 and P = 0.019), with median values ranging from 741.7 to 963.4 µg/L for G4, and for Ag ions, from G4 to G2 and G3 (P < 0.001 for both), with lower medians for G4 (3.7-6.1 µg/L). For Cd ions there was a statistic difference from T1 to T4 in all groups (P = 0.016), with lower values for T4. CONCLUSIONS: Different welding procedures may affect salivary ion concentrations. For most ions there was no significant increase comparing welding and comparing throughout points in the same group. Although TIG welding presented greater Ni ion release, this possibly occurred due to a bigger corrosion of the welded. CLINICAL RELEVANCE: Determining the amount of released metal ions from the use of orthodontic appliances is relevant to ensure the safest method for patients. Welding procedures affect salivary ion concentrations, when comparing ion release triggered by one of the most common devices used for preventive/interceptive orthodontic treatments.

Conventional surgical-orthodontic approach with double-jaw surgery for a patient with a skeletal Class III malocclusion: Stability of results 10 years posttreatment.

This case report presents the treatment of a young man with a skeletal Class III malocclusion. He was treated with a conventional surgical-orthodontic approach in which 2 jaw surgeries were performed. The esthetic facial profile, pleasant smile, appropriate occlusion, and overall good treatment outcome remained stable 10 years after active orthodontic treatment.

Cone-beam computed tomography evaluation of bone plate and root length after maxillary expansion using tooth-borne and tooth-tissue-borne banded expanders.

INTRODUCTION: The objective of this research was to evaluate the buccal bone plate and root length of maxillary permanent first molars using cone-beam computed tomography after maxillary expansion with different activation protocols. METHODS: Cone-beam computed tomography images of growing patients were obtained from the orthodontic department of Pontifical Catholic University of Rio Grande do Sul in Brazil. The groups were Haas-type 2/4 turns, Haas-type 4/4 turns, hyrax-type 2/4 turns, and hyrax-type with alternate rapid maxillary expansions and constrictions (alt-RAMEC) 4/4 turns a day. Tooth length, periodontal insertion, alveolar bone thickness, and intermolar distances were evaluated. The data at the start of treatment and 6 months later were compared using generalized linear models. The intergroup differences were determined by univariate analysis of variance with the Bonferroni adjustment. RESULTS: Tooth length was significantly shortened after expansion in all groups (-0.28 to -0.51 mm), except for the alt-RAMEC group. Bone level variables (bone level and bone level at the tooth tip) changed statistically in all groups, except for the Haas 4/4 turns group. There was significant periodontal attachment loss after rapid maxillary expansion with the hyrax/alt-RAMEC (5.09 mm). The hyrax/alt-RAMEC and hyrax groups had more dehiscences, fenestrations, and exposures of the root. CONCLUSIONS: The consequence of rapid maxillary expansion using the hyrax was alveolar bone resorption, especially in the hyrax/alt-RAMEC group, whereas the Haas expander caused mild root resorption.

Volumetric assessment of alveolar clefts: a literature review.

OBJECTIVE: To conduct a review of the literature on methods for volumetric assessment of alveolar clefts and ascertain which methods are most precise to guide future research. METHODS: The PubMed and MEDLINE databases were searched for English-language reports of clinical and in vitro studies with detailed descriptions of imaging modality, sample characteristics, and method for measurement of alveolar cleft volume. RESULTS: The search strategy yielded 34 articles, of which 14 were selected for in-depth analysis. According to the findings of computed tomography (CT)-based studies, the CT modalities and software employed for assessment were deemed reliable and satisfactory. CONCLUSIONS: Measurement of alveolar cleft volume by the proposed methods and using the equipment and software employed in the analyzed studies has high efficacy and efficiency and can be safely used for cleft lip and palate treatment planning.

Cytotoxic outcomes of orthodontic bands with and without silver solder in different cell lineages.

INTRODUCTION: The safety of orthodontic materials is a matter of high interest. In this study, we aimed to assess the in-vitro cytotoxicity of orthodontic band extracts, with and without silver solder, by comparing the viability outcomes of the HaCat keratinocytes, the fibroblastic cell lineages HGF and MRC-5, and the kidney epithelial Vero cells. METHODS: Sterilized orthodontic bands with and without silver solder joints were added to culture media (6 cm2/mL) and incubated for 24 hours at 37°C under continuous agitation. Subsequently, the cell cultures were exposed to the obtained extracts for 24 hours, and an assay was performed to evaluate the cell viability. Copper strip extracts were used as positive control devices. RESULTS: The extracts from orthodontic bands with silver solder joints significantly reduced the viability of the HaCat, MRC-5, and Vero cell lines, whereas the viability of HGF was not altered by this material. Conversely, the extracts of orthodontic bands without silver solder did not significantly modify the viability index of all evaluated cell lines. CONCLUSIONS: Except for HGF fibroblasts, all tested cell lines showed decreased viability percentages after exposure to extracts of orthodontic bands containing silver solder joints. These data show the relevance of testing the toxicity of orthodontic devices in different cell lines.

Juvenile idiopatic arthritis in orthodontics: Case report with a 6-year follow-up.

Juvenile idiopathic arthritis is a childhood disease that causes joint swelling and pain, and limitation in the range of joint movements. It is characterized by progressive destruction of the joints. Juvenile idiopathic arthritis is the most frequent systemic inflammatory disease of the temporomandibular joint. When the temporomandibular joint is involved, orthodontic treatment becomes more challenging. This case report shows the treatment of a young patient with a Class II subdivision malocclusion and juvenile idiopathic arthritis. Excellent results were achieved and maintained at the 6-year follow-up, when neither clinical symptoms nor radiographic changes in the temporomandibular joint were seen.

Post-extraction evaluation of sockets with one plate loss--a microtomographic and histological study.

AIM: The aim of this study is to evaluate the characteristics of socket repair after teeth extraction with loss of a bone plate. MATERIAL AND METHOD: Lower incisors were extracted from 120-day-old male rabbits. A standardized defect of 5 mm in the buccal plate was created in one of the socket sites. Furthermore, complete closures of the sockets entrance were performed. Two groups of biopsies were obtained: one with 14 days of healing and the other with 112, to perform the micro-CT and histological evaluations of the tested group with plate loss comparing with the control group with the intact buccal bone wall. RESULTS: Plate loss sites demonstrated reduction in width when compared to the intact ones and, this difference decreased with time. CONCLUSION: Long-term analysis showed that plate loss interfered in final ridge measurements by reducing the middle portion of the socket width compared to the intact plate sockets. The histological and micro-CT qualitative analysis showed that both sites presented similar pattern of healing, despite the reduced dimension found in plate loss sites.

Midfacial Protraction With Skeletal Anchorage After Pterygomaxillary Separation.

The present article reports the treatment of a 7-year-old girl with maxillary hypoplasia associated with multiple tooth agenesis through maxillary protraction with skeletal anchorage and pterygomaxillary separation. Two titanium mini-plates were placed in the lateral region of the nasal cavity and used as anchorage for maxillary protraction with a reverse-pull facemask. Pterygomaxillary separation was also performed to enhance the effects of maxillary protraction. One week after surgery, 300 g of force was applied on each side to protract the maxilla. Active treatment time was 4 months, with 12 additional months of follow-up. Analysis of the cone beam computed tomography images demonstrated that skeletal anchorage enabled the correction of the maxillomandibular discrepancy, with an improvement in facial appearance and occlusion and with no dental effects. Pterygomaxillary separation was not effective, showing no superior orthopedic response on maxillary advancement or restrictions to maxillary growth in the 12-month post-treatment follow-up.

Three-dimensional monitoring of root movement during orthodontic treatment.

INTRODUCTION: A significant objective of orthodontic treatment is to achieve proper and stable tooth positions that involve not only the crowns, but also their roots. However, the current methods of clinically monitoring root alignment are unreliable and inaccurate. Therefore, the purpose of this study was to develop a methodology that can accurately identify root position in a clinical situation. METHODS: Pretreatment and posttreatment cone-beam computed tomography (CBCT) and extraoral laser scans of study models of a patient were obtained. Threshold segmentation of the CBCT scans was performed, resulting in 3-dimensional surface models. The pretreatment CBCT teeth were isolated from their respective arches for individual tooth manipulation. These isolated pretreatment CBCT teeth were superimposed onto the posttreatment surface scan depicting the expected root position setup. To validate the accuracy of the expected root position setup, it was compared with the true root position represented by the posttreatment CBCT scan. Color displacement maps were generated to measure any differences between the expected and true root positions. RESULTS: Color map analysis through crown superimposition showed displacement differences of 0.148 ± 0.411 mm for the maxillary roots and 0.065 ± 0.364 mm for the mandibular roots. CONCLUSIONS: This methodology has been demonstrated to be an accurate and reliable approach to visualize the 3-dimensional positions of all teeth, including the roots, with no additional radiation applied.

Cytotoxicity and genotoxicity of orthodontic bands with or without silver soldered joints.

Stainless steel bands, with or without silver soldered joints, are routinely used in orthodontics. However, little is known about the toxic biological effects of these appliances. The aims of this study were to evaluate the cytotoxic, cytostatic, genotoxic and DNA damage-inducing effects of non-soldered bands (NSB) and silver soldered bands (SSB) on the HepG2 and HOK cell lines and to quantify the amount of ions released by the bands. The 24-h metallic eluates of NSBs and SSBs were quantified by atomic absorption spectrophotometry. An MTT reduction assay was performed to evaluate the cytotoxicity, alkaline and modified comet assays were employed to measure genotoxicity and oxidative DNA damage effects, and cytokinesis-block micronucleus cytome (CBMN-Cyt) assays were used to verify DNA damage, cytostasis and cytotoxicity. Ag, Cd, Cr, Cu and Zn were detected in SSB medium samples, and Fe and Ni were detected in both the SSB and NSB medium samples. The SSB group induced stronger cytotoxic effects than the NSB group in both evaluated cell lines. NSB and SSB induced genotoxicity as evaluated by comet assays; stronger effects were observed in the SSB group. Both groups induced similar increases in the number of oxidative DNA lesions, as detected by the FPG and Endo III enzymes. Nucleoplasmic bridges, biomarkers of DNA misrepair and/or telomere end fusions, were significantly elevated in the SSB group. The SSB eluates showed higher amounts of Ni and Fe than NSB, and all the quantified ions were detected in SSB eluates, including Cd. The SSB eluates were more cytotoxic and genotoxic than the NSB samples. Based on these results, we propose that other brands, materials and techniques should be further investigated for the future manufacture of orthodontic appliances.

Effect of printing technology and orientation on the accuracy of three-dimensional printed retainers.

OBJECTIVES: To evaluate the impact of printer technology and print orientation on the accuracy of directly printed retainers. MATERIALS AND METHODS: Digital retainers were printed with two different printing technologies: digital light processing (DLP) and stereolithography (SLA), using two different orientations: 0° and 90°. After printing, the retainers (n = 40) were scanned using cone-beam computed tomography. The DICOM files were then converted into standard tessellation language (STL) files. Comparison of the printed retainers with a master file was done by superimposition using a three-dimensional (3D) best-fit tool in Geomagic software. A ±0.25 mm tolerance was set to detect differences between the superimposed files. Statistical analysis was conducted (Kruskal-Wallis and Wilcoxon-Mann-Whitney tests, with Bonferroni correction). RESULTS: The lowest median average deviation was observed for the DLP horizontally printed models (median, [interquartile range (IQR)] = 0.01 mm, [-0.01, 0.02]) followed by the SLA horizontally printed retainers (median, [IQR] = 0.05 mm, [0.03, 0.07]). The highest median inside the tolerance levels ratio was observed for the horizontally SLA printed retainers (median, [IQR] = 78.9%, [74.4, 82.4%]) followed by the horizontally DLP printed retainers (median, [IQR] = 78.2%, [74.5, 80.7%]). CONCLUSIONS: Both technologies (DLP and SLA) showed 3D printed results compatible with orthodontic clinical needs. Printing orientation was more important than printer type regarding its accuracy. Additional studies are needed to evaluate the accuracy of direct printed appliances clinically.

Effect of printing technology, layer height, and orientation on assessment of 3D-printed models.

BACKGROUND: Three-dimensional (3D) printing technologies have become popular in orthodontics. The aim of this study is to determine the effect of printing technology, orientation, and layer height on the accuracy of 3D-printed dental models. METHODS: The maxillary arch of a post-treatment patient was scanned and printed at different orientations (0°, 90°) and layer thicknesses (25 µm, 50 µm, 100 µm, and 175 µm) using two different printing technologies (digital light processing and stereolithography). The 120 models were digitally scanned, and their average deviation from the initial model was analyzed using 3D algorithm. A multivariable linear regression analysis was used to estimate the effect of all variables on the average deviation from the initial model for the common layer thicknesses (50/100 µm). Finally, one-way ANOVA and Tukey posthoc test was used to compare the stereolithography (SLA) 25 µm and digital light processing (DLP) 175 µm groups with the groups that showed the least average deviation in the former analysis. RESULTS: The multivariable linear regression analysis showed that the DLP 50 µm (mean ± SD: -0.022 ± 0.012 mm) and 100 µm (mean ± SD: -0.02 ± 0.009 mm) horizontally printed models showed the least average deviation from the initial model. Finally, the DLP 175 µm horizontally printed models (mean ± SD: 0.015 ± 0.005 mm) and the SLA 25 µm horizontally (mean ± SD: 0.011 ± 0.005 mm) printed models were more accurate. CONCLUSIONS: All the models showed dimensional accuracy within the reported clinically acceptable limits. The highest accuracy was observed with DLP printer, 175 µm layer thickness, and horizontal orientation followed by SLA printer, 25 µm layer thickness, and horizontal orientation.

Embryotoxicity and teratogenesis of orthodontic acrylic resin in zebrafish.

Objectives: This study investigated the in vivo embryotoxicity, teratogenic potential, and additional effects of orthodontic acrylic resin as well as its components, utilizing zebrafish as a model organism. The research focused on morphological, cardiac, behavioral, and cognitive evaluations that were performed on embryos and larval-stage animals subjected to chronic exposure. Materials and methods: Embryo and larval-stage zebrafish were categorized into five experimental groups, which were further subdivided into five subgroups. These subgroups included three specific doses for each tested substance, a control with the vehicle (0.1 % dimethyl sulfoxide in water), and an absolute control (water). Assessments were performed on day 5 post-fertilization, which included morphological, cardiac, behavioral, and cognitive evaluations. All experiments had a sample size of ten animals and were performed in triplicate. Survival and hatching rates were analyzed using the Kaplan-Meier test, while other measurements were assessed using one-way analysis of variance (ANOVA), followed by the Tukey post hoc test. Results: Statistically significant differences were observed between the control and treatment groups across all the tested substances for heart rate, cognitive responsiveness, and cellular apoptosis. However, survival, hatching rate, and other parameters exhibited no significant variation, except for the highest dose in the dibutyl phthalate group, which demonstrated a notable difference in survival. Conclusions: Chronic exposure to acrylic resin and its components may be associated with decreased cognitive ability and cardiac rhythm, as well as an increase in the level of cellular apoptosis in zebrafish.

MISMARPE protocol: minimally invasive surgical and miniscrew-assisted rapid palatal expansion.

OBJECTIVE: The purpose of this article is to present the MISMARPE technique, a new minimally invasive surgical procedure to treat maxillary transverse atresia in adult patients under local anesthesia and on an outpatient basis. TECHNIQUE DESCRIPTION: The technique consists of miniscrew-assisted rapid palatal expansion (MARPE) associated with a minimally invasive approach using maxillary osteotomies, latency and activation periods until the desired expansion is achieved. The present MISMARPE technique was performed in 25 consecutive cases with a success rate of 96%, yielding good skeletal outcomes with minimal trauma. The expander appliances, with their anchorage types, and a description of the surgical steps of the MISMARPE technique are presented. CONCLUSION: MISMARPE is a new and effective alternative for less invasive treatment of maxillary transverse deficiency in adults, compared to conventional surgery. Emphasis is placed on the importance of systematic and well-established protocols, for executing the procedures safely and predictably.

Combining traditional techniques to correct anterior open bite and posterior crossbite.

The treatment of anterior open bite often requires the use of skeletal anchorage to prevent excessive eruption of the posterior teeth and consequent downward rotation of the mandible. However, this procedure might not always be accomplished. This article reports the successful treatment of an anterior open bite and a posterior crossbite in a young boy, combining traditional techniques and involving high-pull maxillary traction to help growth to correct the skeletal Class II malocclusion without skeletal anchorage. The vertical dentoalveolar contribution of maxillary growth was also favorable to close the bite, whereas cross-elastics corrected the axial inclination of the mandibular posterior teeth, eliminating the inverted posterior crossbite. The open bite was completely closed with edgewise appliances, which also achieved normal overjet, intercuspation, and incisor exposure on smiling. Traditional mechanics for the treatment of open bite and crossbite remain a useful alternative when patients do not accept skeletal anchorage.