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1.
Biomedicines ; 11(12)2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38137526

RESUMO

The skeletal and dental effects of rapid maxillary expansion (RME) have been extensively studied, but high-quality research is still needed to determine the three-dimensional (3D) effects of RME. The aim of this study was to compare skeletal and dentoalveolar parameters through cone-beam computed tomography (CBCT) pre- (T1) and post-treatment (T2) with respect to RME. Twenty growing patients (mean age 10.7 years) were treated with a Hyrax-type expander. A 3D CBCT was performed at T1 and T2, measuring nasal width, maxillary width, palatal height, maxillary arch perimeter, angulation of the upper first molar, and intermolar width. The mean palatal suture opening was 2.85 ± 0.62 mm (p < 0.0001). Nasal width increased 1.28 ± 0.64 mm and maxillary width 2.79 ± 1.48 mm (p < 0.0001). In contrast, palatal height was reduced 0.65 ± 0.64 mm (p < 0.0001). Regarding arch perimeter, the radicular perimeter increased 2.89 ± 1.80 mm, while the coronal perimeter increased 3.42 ± 2.09 mm (p < 0.0001). Molar angulation increased 5.62 ± 3.20° for the right molar and 4.74 ± 2.22° for the left molar (p < 0.0001). Intermolar width increased 5.21 ± 1.55 mm (p < 0.0001). Treatment with Hyrax produced a significant opening in the mean palatal suture. Also, a significant increase in nasal width, maxillary width, arch perimeter, molar angulation, and intermolar width, and a decrease in palatal height, were observed.

2.
BMC Oral Health ; 23(1): 850, 2023 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-37951878

RESUMO

BACKGROUNDS: The aim of this longitudinal clinical study is to analyse and compare according to location, degree and type, the pain presented by patients during their first year of treatment, as well as the quality of oral life after the placement of two types of orthodontic appliances: conventional brackets and removable Invisalign ® aligners. METHODS: The sample consisted of 140 patients grouped into 2 study groups of 70 patients each. The first group (brackets group- BG), with fixed multibracket appliances, using the MBT technique and a 0.022" slot. The second group (invisaling group- IG), in treatment with removable aligners (IG), using the Invisalign ® system. They were providen with a questionnare where they had to record the degree (mild, moderate or intense), the type and location of the pain monthly during the first year of treatment. The second form was the Spanish version of the OHIP-14, oral quality of life questionnaire, which was provided the twelfth month after the start of treatment. RESULTS: In both groups, we found that the most frequent location of pain occurred during the first phase: mandibular for the IG group and maxillary in the BG group. Throughout the whole analysis, the intensity was mild-moderate with lower values in the conventional brackets' group. The BG group reported acute pain while the IG group reported sensitive pain during the first month; later both reported sensitive pain. CONCLUSIONS: There are differences in terms of periodontal pain in its degree, location, and type according to the different orthodontic techniques used. TRIAL REGISTRATION: The study was approved by the bioethics committee of the University of Salamanca (USAL_20/516).


Assuntos
Dor Aguda , Aparelhos Ortodônticos Removíveis , Humanos , Qualidade de Vida , Aparelhos Ortodônticos Fixos , Estudos Longitudinais , Dor Aguda/etiologia
3.
Children (Basel) ; 10(8)2023 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-37628310

RESUMO

INTRODUCTION: Malocclusions have a negative impact on oral-health-related quality of life (OHRQoL). Posterior cross-bite is one of the most prevalent malocclusions in the preadolescent population. This study investigated the influence of posterior cross-bites (unilateral or bilateral) on OHRQoL in an 11- to 14-year-old population. MATERIALS AND METHODS: A pilot case-control study was carried out at the Dental Clinic of the University of Salamanca between 2021 and 2023. A consecutive sample of 120 preadolescent patients aged 11 to 14 years old was recruited. Three groups were analyzed: a control group (no posterior cross-bite) (n = 40), a group with unilateral posterior cross-bite (n = 40), and a group with bilateral posterior cross-bite (n = 40). To analyze the OHRQoL, the Spanish version of the Child Perception Questionnaire (CPQ-Esp11-14) was used. RESULTS: The mean age of the sample was 12.2 years old (±0.96 years). The group of patients with a bilateral posterior cross-bite was shown to have higher scores in all dimensions of the CPQ-Esp11-14, as well as a higher total score. Sex only influenced the oral symptom dimension of the CPQ-Esp11-14 questionnaire; in this dimension, the girls described a greater impact. Age did not influence OHRQoL. CONCLUSION: The presence of a posterior cross-bite had a negative impact on OHRQoL in the preadolescent population that was studied.

4.
J Pers Med ; 13(5)2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37241029

RESUMO

The aim of this study was to analyze a novel digital technique to quantify the distal tooth displacement and derotation angle produced by the Carriere Motion Appliance (CMA). Twenty-one patients with a class II molar and canine relationship underwent orthodontic treatment with CMA. All patients were exposed before (STL1) and after the CMA placement (STL2), submitted to a digital impression, and afterwards, data were uploaded to specific cephalometric software to allow automatic mesh network alignment of the STL digital files. Subsequently, the distal tooth displacement of the upper canines and first upper molars, as well as the derotation angle of the first upper molars were analyzed using the Pearson correlation coefficient (ρ). Repeatability and reproducibility were analyzed using Gage R&R statistical analysis. An increase in canine displacement was correlated with an increase in contralateral canine displacement (ρ = 0.759; p < 0.000). An increase in canine displacement was correlated with an increase in molar displacement (ρ = 0.715; p < 0.001). An increase in upper first molar displacement was correlated with an increase in the contralateral upper first molar displacement (ρ = 0.609; p < 0.003) and the canine displacement (ρ = 0.728; p < 0.001). The distal tooth displacement showed a repeatability of 0.62% and reproducibility of 7.49%, and the derotation angle showed a repeatability of 0.30% and reproducibility of 0.12%. The novel digital measurement technique is a reproducible, repeatable, and accurate method for quantifying the distal tooth displacement of the upper canine and first upper molar, as well as the derotation angle of the first upper molars after using CMA.

5.
Artigo em Inglês | MEDLINE | ID: mdl-36078481

RESUMO

The aim of this study was to evaluate the oral-health-related quality of life (OHRQoL) and anxiety levels of adult patients undergoing orthodontic treatment with fixed multibracket appliances. MATERIALS AND METHODS: The study was carried out at the Dental Clinic of the University of Salamanca in 2021. It included 120 adult patients between 19 and 45 years of age undergoing orthodontic treatment with conventional metal brackets. The data collection instruments chosen were the state-trait anxiety inventory (STAI) to assess anxiety levels and the OHIP-14 questionnaire to measure the OHRQoL. Anxiety levels and OHRQoL were analyzed one month after starting treatment. RESULTS: The mean age was 31.7 years ± 6.5 years; 68 patients were women (56.7%) and 52 were men (43.3%). Psychological disability was the dimension of the OHIP-14 questionnaire that was found to have the greatest impact (3.20 ± 1.08) on patients, as compared to the dimension of disability, which had the lowest impact on the oral-health quality of life (0.37 ± 0.56). The mean total score of the OHIP-14 questionnaire was 11.93 (±2.19). There was no statistically significant influence from either sex or age on the anxiety and oral-health quality of life of the participants; however, there was a significant relationship between the dimensions of physical disability and anxiety traits. CONCLUSIONS: The physical disability dimension of the OHIP-14 questionnaire increased the anxiety level of adult patients treated with conventional brackets. The impact of orthodontic treatment on adult patients may negatively influence their levels of anxiety.


Assuntos
Saúde Bucal , Qualidade de Vida , Adulto , Ansiedade/epidemiologia , Feminino , Humanos , Masculino , Aparelhos Ortodônticos Fixos , Qualidade de Vida/psicologia , Inquéritos e Questionários
6.
Artigo em Inglês | MEDLINE | ID: mdl-35954634

RESUMO

One of the risks that we find after orthodontic treatment is the secondary appearance of white spot lesions (WLS) after the removal of fixed multi-bracket appliances. Today, there are several treatment methods, resin infiltration being the most used in the most serious cases. The objective of this study is to carry out a systematic review and meta-analysis to determine the efficacy and stability in the variables of color and gloss, six months after resin infiltration. A comprehensive search was performed in the following databases: PubMed, Embase, Google Scholar, Scopus, Medline, and Web of Science. Articles published in the last 10 years were selected, including in vivo studies with a six-month follow-up. PRISMA guidelines were followed to carry out this systematic review. All studies where the application of resin was performed on carious lesions were discarded. Once the inclusion and exclusion criteria were applied, a final sample of four articles was obtained, on which the review and meta-analysis were carried out. Once examined, all authors considered that there was an immediate improvement in both variables. However, statistically significant differences were obtained in the color change outcome, but not in the brightness outcome in the subgroup analysis after six months of icon resin infiltration.


Assuntos
Cárie Dentária , Aparelhos Ortodônticos Fixos , Cor , Cárie Dentária/terapia , Diagnóstico Bucal , Humanos , MEDLINE , PubMed
7.
Artigo em Inglês | MEDLINE | ID: mdl-35329271

RESUMO

The purpose of this study was to assess the accuracy and reliability of tooth width measurements and Bolton Indices delivered by the Clin-Check Pro 6.0 software (Align Technology, San José, CA, USA). Fifty-four plaster casts were selected and measured with a manual calliper by a trained and calibrated observer. The data gathered were compared with those delivered by the software on the corresponding fifty-four virtual casts. The method reliability of the software was assessed by comparing the measurements performed by the software on 201 pairs of clin-checks corresponding to two consecutive treatment phases. Accuracy and reliability were statistically assessed using a mixed model. The software tends to provide larger widths compared with the manual method. Statistically significant differences were found in 23 teeth. At a global level, the mean difference between the methods was -0.19 mm, with a Dahlberg error of 0.24 mm and an intraclass correlation coefficient of 0.98. The Bolton Indices delivered by the two methods had a moderate correlation (ICC = 0.59; 0.69). The within method reliability of the software was extremely high. Tooth width measurements delivered by the software, despite the positive bias, can be considered accurate and clinically acceptable for all teeth except molars. The Bolton Indices made available by the software are not accurate and clinically acceptable, especially in the case of mandibular excess.


Assuntos
Modelos Dentários , Dente , Estudos Transversais , Reprodutibilidade dos Testes , Software
8.
Healthcare (Basel) ; 10(1)2022 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-35052294

RESUMO

Oral-health-related quality of life (OHRQoL) is defined as the impact of oral health on activities of daily living. Malocclusions are a public health problem with a high prevalence. Different studies have concluded that malocclusions negatively affect OHRQoL in patients of all ages. The aim of this study was to analyze the influence of having an anterior open bite on the OHRQoL of adult patients. MATERIALS AND METHODS: A case-control study (1:1) was carried out with a sample size of 80 adults at the University of Salamanca in 2021. The case group (n = 40) was made up of patients with an anterior open bite, and the control group (n = 40) contained patients without an anterior open bite. OHRQoL was assessed using the Oral Health Impact Profile-14 (OHIP-14) questionnaire. The influences of gender and age on the OHRQoL of the patients were also analyzed. RESULTS: There were no significant differences in gender or age between the case and control groups. An anterior open bite was not found to influence the OHRQoL of adult patients. Age was not shown to significantly influence OHRQoL. Female patients with an anterior open bite had higher scores in the handicap domain of the OHIP-14 questionnaire compared with male patients (p < 0.05). CONCLUSIONS: Anterior open bite can influence the OHRQoL of orthodontic patients. Gender can be considered an influencing factor.

9.
J Pers Med ; 12(1)2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-35055411

RESUMO

The aim of this study is to analyze the skeletal and dentoalveolar morphological characteristics of the maxillary in subjects with a unilateral palatally impacted canine using Cone Beam Computed Tomography (CBCT). A retrospective clinical study was conducted of 100 adult patients divided into two groups: one consisting of patients with a unilaterally palatally impacted maxillary canine (GI), with the subgroups in the right and left hemiarches (GI-R and GI-L), and the second, without impacted canine, as the control group (CG). The CBCT measured skeletal variables (maxillary basal width and alveolar crest height) and dentoalveolar variables (inclination of the upper incisor, tooth lengths of incisors and canines, arch length, tooth size and bone dental discrepancy). In skeletal variables, statistically significant differences were found in alveolar crest height (ACH) in all groups and subgroups (p < 0.01). In the dentoalveolar variables, there were differences in the angle of the upper incisor (II) and lateral incisor length (LLIL) between the GI and GC and the angle of the upper incisor (II'), arch length (AL') and arch length-tooth size discrepancy (ATD') among the GI subgroups (p < 0.01). There are skeletal and dentoalveolar differences in patients with unilateral palatally impacted maxillary canines, with lower angular and linear measurements compared with patients without impaction.

10.
Int J Legal Med ; 136(1): 319-328, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34693478

RESUMO

Sex estimates is a key step of biological profile assessment in a forensic or anthropologic context. In this study, the sexual dimorphism of the frontal bone was analyzed to assess the accuracy of sex estimates using a geometric morphometric approach in a pre-pubertal and post-pubertal sample. The shape of the frontal bone was digitized on the lateral cephalograms of 87 pre-pubertal subjects (42 males, mean age 10.14, SD ± 1.48 years; 45 females mean age 10.02, SD ± 1.11 years) and 103 post-pubertal ones (53 males, mean age 29.33 SD ± 11.88 years; 50 females, mean age 26.77 SD ± 11.07 years). A generalized Procrustes analysis (GPA) was performed for shape analyses, filtering the effects of position, rotation, translation, and size. A principal component analysis (PCA) was performed on the GPA transformed variables, and a multiple logistic regression model was used to assess the accuracy of sex estimates. In both age groups, the average size of the centroid was significantly larger in males. The females presented shapes with a shorter distance between P2 (glabella) and P1 (supratoral) and a general narrowing of the structure on the sagittal plane. In the pre-pubertal group, the shape difference was not statistically significant. In the post-pubertal group, the mean shape was significantly different between the sexes. The method displayed a high accuracy for sex estimates (88.7% males, 90.3% females) also when applied in a validation sample (82.6% males and 94.1% females). The described morphometric analysis of the frontal bone is based on a limited number of landmarks, which allows sex estimates with high accuracy in post-pubertal subjects, while it is not applicable in pre-pubertal ones.


Assuntos
Osso Frontal , Determinação do Sexo pelo Esqueleto , Adulto , Criança , Análise Discriminante , Feminino , Antropologia Forense/métodos , Osso Frontal/anatomia & histologia , Humanos , Masculino , Análise de Componente Principal , Caracteres Sexuais , Determinação do Sexo pelo Esqueleto/métodos
11.
J Pers Med ; 11(10)2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34683103

RESUMO

The aim of the study was to validate a novel digital measurement method to quantify the volume of the midpalatal suture after rapid maxillary expansion (RME). MATERIAL AND METHODS: Eight patients with maxillary skeletal transverse deficiency were submitted to palatine suture expansion using the McNamara orthodontic appliance during a period of nine months. After 30 days of treatment, all patients were exposed postoperatively to a cone-beam computed tomography (CBCT) scan. Afterwards, the scans were uploaded into the three-dimensional orthodontic-planning software to allow the volumetric assessment of the palatine suture expansion through palatine rapid maxillary expansion using a McNamara appliance. The repeatability was analyzed by repeating twice the measures by a single operator and reproducibility was analyzed by repeating three times the measures by two operators, and Gage R&R statistical analysis was performed. RESULTS: The expansion of the midpalatal suture by means of the rapid maxillary expansion technique, in terms of digital volume measurement, showed a repeatability value of 0.09% and between the two operators a reproducibility value of 0.00% was shown. CONCLUSIONS: The novel measurement technique demonstrated a high repeatability and reproducibility rate for volume assessment of the palatine suture expansion through palatine rapid maxillary expansion technique.

12.
Head Face Med ; 17(1): 24, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34233698

RESUMO

BACKGROUND: Determine the exact slot dimension of a sample of a MBT prescription stainless steel conventional brackets from different manufacturers to compare the actual values with the nominal ones declared by the manufacturers and to verify the compliance with tolerance limits given by the ISO 27020:2019. Different batches from each manufacturer were evaluated to determine whether or not they are different in size. In addition, the geometry of the slot walls was assessed. METHODS: 360 stainless steel preadjusted orthodontic brackets of 12 different manufacturers were assessed. All brackets had a nominal slot size of 0.022 by 0.028 inches, belonged to the right upper central incisor, and were fabricated with the metal injection molding technique (MIM). For each manufacturer, three different manufacturing batches were evaluated. Brackets were coded using a single-blind design. RESULTS: All bracket systems in the study group except one displayed a statistically significant difference with the nominal declared value, although only four of the systems did not comply with the tolerance limits established by the ISO 27020:2019. In most of the systems, the slot height was oversized when compared to the nominal one. A significant interbatch variability was found in most of the evaluated systems. Most of the brackets walls were divergent. CONCLUSIONS: The dimensional accuracy of commercially available metal brackets is not guaranteed. The respect for the norm should be enforced as well as the quality controls along the manufacturing process since orthodontic brackets are a precision medical device.


Assuntos
Braquetes Ortodônticos , Análise do Estresse Dentário , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Método Simples-Cego , Aço Inoxidável
13.
Biology (Basel) ; 10(5)2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33924818

RESUMO

The objective of this prospective clinical study was to analyze the pain (intensity, location and type) that patients presented after the placement of different types of orthodontic appliances: conventional, low friction, lingual and aligners. The sample consisted of 120 patients divided into four groups: conventional (CON), low friction (LF), lingual (LO) and aligners (INV). The participants were given the Short-Form McGill Pain Questionnaire (Ortho-SF-MPQ), where they had to record the pain intensity (no pain, mild, moderate or intense) and the periodontal location at different time points, from the first 4 h to 7 days after the start of treatment. In all the study groups, the most frequent location was both anterior arches, with maximum values between 56.7% (CON group at 24 h) and 30% (LO group at 4 h). The "whole mouth" and "complete lower arch" locations were indicated only by the patients in the lingual group. Regarding pain intensity, the patients reported a higher percentage of mild-moderate pain during the first 3 days of treatment (96.7% in LO at 4 h, 86.7% in CON, 83.3% in LF and 90% in INV at 24 h); later, the reported pain decreased to no pain/mild pain, especially in the lingual group, until reaching values close to zero at 7 days post-treatment. The most frequent type of pain was acute in the low friction and lingual groups (with maxima of 60% and 46.7% at 24 h, respectively). On the contrary, in the conventional (36.7% at 4 h) and Invisalign (40% at 24 h) groups, the sensitive type was the most frequent. There are differences regarding periodontal pain in its intensity, location and type according to the use of different orthodontic techniques.

14.
Medicina (Kaunas) ; 57(2)2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33671217

RESUMO

Background and objectives: The aim of this study was to evaluate the influence of friction on design of the type of bracket, patients' perception of pain and the impact on their oral health-related quality of life. Materials and Methods: A randomized clinical trial was carried out with 90 patients (62.2% women and 37.8% men) with three kinds of fixed multi-bracket appliances: Conventional (GC), fixed multi-bracket low friction (GS) and self-ligating (GA). The VAS (Visual Analogue Scale) was used to determine pain during the first seven days of treatment at different points in time. The patients were also given the OHIP-14 (Oral Health Impact Profile) questionnaire to analyse their oral health-related quality of life (OHRQoL) after the first 30 days of treatment. The ANOVA test was used for the analysis of the variables and the post hoc Bonferroni test for the comparison between groups. Results: Maximum pain was observed between one and two days after the start of treatment. The GC group showed the greatest degree of pain, with maximum values (4.5 ± 2.0) at 24 h. The self-ligation brackets show lower impact on patients' oral health-related quality of life (0.8 ± 2.2, p < 0.01). Conclusions: Friction in the type of bracket influences pain and the Oral Health-Related Quality of Life of patients who use multi-bracket fixed orthodontics.


Assuntos
Braquetes Ortodônticos , Qualidade de Vida , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos
15.
J Clin Med ; 9(7)2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32635196

RESUMO

The aim of this study was to compare pain and its relationship with the oral quality of life of patients with different types of orthodontic appliances: conventional and conventional low-friction brackets, lingual brackets, and aligners. A prospective clinical study was carried out with a sample size of 120 patients (54 men, 66 women) divided into 4 groups of 30 patients each. The modified McGill questionnaire was used to measure pain at 4, 8, and 24 h and 2, 3, 4, 5, 6, and 7 days after the start of treatment, and the Oral Health Impact Profile-14 (OHIP-14) questionnaire was used to measure the oral-health-related quality of life (OHRQoL) in the first month of treatment. The maximum peak of pain was obtained between 24 and 48 h of treatment. It was found that patients in the lingual orthodontic group described lower levels of pain at all times analyzed, and their scores in the total OHIP-14 indicated less impact on their oral quality of life (1.3 ± 1.2, p < 0.01) compared with the other groups analyzed. There was little difference with the aligners group (Invisalign) (1.7 ± 1.9, p < 0.01). The technique used influences the pain and quality of life of patients at the start of orthodontic treatment.

16.
Orthod Craniofac Res ; 23(4): 462-470, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32449978

RESUMO

OBJECTIVE: To perform a bibliometric analysis on the top-cited articles over the last three decades from 1989 to 2018, using a longitudinal set-up, in order to analyse how articles' features have evolved over time. SETTING AND SAMPLE POPULATION: A sample of 312 articles divided into three subgroups of 104 top-cited articles for each decade were included. The h-index value was used to determine the sample size. MATERIALS AND METHODS: The articles were identified through a search in the category "dentistry oral surgery and medicine" of the Web of Science database. The information relative to the articles was collected. Descriptive statistics was used to describe the articles and the journals; selected parameters were analysed with the Kruskal-Wallis and the Mann-Whitney U test at the 0.05 level of significance. RESULTS: The top-cited articles were published mainly by orthodontic journals. Along the last two decades, the scientific contribution of Asian and South American countries rose significantly. The trending topics varied in each decade. Skeletal anchorage-related articles dominated the production of the decade 1999-2008 while new technologies as CBCT displayed a higher prevalence in the last decade, where new topics such as corticotomy-assisted orthodontics started to appear. The number of multi-authored articles increased while the articles from no university institutions decreased. CONCLUSION: The publications in the three studied decades were significantly different in terms of numbers and characteristics. A longitudinal set-up allows to study the evolution of the scientific production and how the area of interest has developed over time.


Assuntos
Ortodontia , Publicações , Bibliometria , Gerenciamento de Dados , Estudos Longitudinais
17.
J Clin Exp Dent ; 8(2): e141-5, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27034753

RESUMO

BACKGROUND: During the treatment of orthodontics, in the mechanics of slide, there takes place friction, which they reduce the slide of the arch across bracket. Therefore, clinical there takes place an increase of the time of treatment. There are different the technologies that try to reduce this friction, as the self-ligating braces. The purpose of this study was to research the in vitro behavior of JAL 90458 as a buffering agent which reduces friction between brackets and stainless steel arch wires of different cross sections and sizes. MATERIAL AND METHODS: Three types of stainless steel wires with different cross sections and three types of ligatures were used with and without JAL 90458 to measure the friction according to the time and distance traveled by the brackets on an inclined plane with two angulations. The Kruskal-Wallis one-way analysis of variance by ranks was applied to determine the degree of friction between the group using and the group not using the product (P ≤ .05). RESULTS: Separate analysis of the arch wires, ligatures and angulation with and without the compound revealed statistically significant differences between the groups, showing that friction was reduced significantly when JAL 90458 was used (P ≤ .01). The 0.021x0.025" arch wires and the arch wires attached using elastic ligatures produce the least resistance to sliding among all of those analyzed when the product was not used (P ≤ .05). CONCLUSIONS: The results show that JAL 90458 reduces friction independently of arch wire cross section, type of ligature and angulation of the measuring instrument. KEY WORDS: Friction, JAL 90458, arch wires, ligatures, in vitro.

18.
J Lasers Med Sci ; 7(4): 214-219, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28491255

RESUMO

Introduction: When aesthetics is compromised, dental ceramics are excellent materials for dental restorations; owing to their optical properties and biocompatibility, zirconia ceramics are particularly interesting. Self-adhesive resin cements are the most suitable for bonding to zirconia ceramics, but traditional adhesive chemistry is ineffective and surface treatments are required to improve the adhesive bonding between resin and zirconia. The aim of this study was to evaluate the effect of femtosecond laser treatment on the shear bond strength (SBS) of self-adhesive resin cement on zirconia surfaces and to contrast it with other different surface conditioning methods. Methods: Sixty square-shaped zirconia samples were divided randomly into four groups (n = 15) according to their surface conditioning method: the NT group - no surface treatment; the APA25 group - airborne abrasion with 25 µm alumina particles; the TSC group - tribochemical silica coating, and the FS group - femtosecond laser irradiation (800 nm, 4 mJ, 40 fs/pulse, 1 kHz). Self-adhesive resin cements were bonded at the centre of samples, and after 72 hours, they were tested for SBS with a universal testing machine at a crosshead speed of 0.5 mm/min, until fracture. Five zirconia surfaces for each group were subjected to a surface morphology analysis by scanning electron microscopy (SEM). The failure modes were noted and a third of the specimens were prepared to morphological analysis. Results: The NT group showed lower SBS values than the other groups. Femtosecond laser treatment demonstrated higher values than the control and APA25 groups and similar values to those of the TSC group. In the APA25 group, the surface conditioning method had values close to those of the TSC group, but lower than those obtained with femtosecond laser treatment. Conclusion: The treatment of zirconia with femtosecond laser irradiation created a consistent and profound surface roughness, improving the adhesive effectiveness of the zirconia-resin interface.

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