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1.
J Orthod ; 46(4): 287-296, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31595815

RESUMO

OBJECTIVE: To carry out a UK national clinical audit of orthognathic acceptance criteria and information provided to orthognathic patients before treatment. DESIGN: National clinical audit. SETTING: Data collected using Bristol Online Surveys. PARTICIPANTS: Sixty-nine UK hospital orthodontic departments submitted data. METHODS: Data were collected at two time points using Bristol Online Surveys over a period of 12 months. These were before treatment at the first multidisciplinary clinic (MDT) and immediately after surgery. The data collected included: Index of Orthognathic Functional Treatment Need (IOFTN); Index of Orthodontic Treatment Need (IOTN); age; previous orthodontic treatment; attendance at an MDT; treatment times; and information provision. RESULTS: Eighty-five units agreed to take part in the audit with 69 submitting data, giving a response rate of 81%. The data from 3404 patients were uploaded, 2263 before treatment and 1141 immediately after surgery. Of patients, 91.07% had an IOFTN score of 4 or 5 and 88.73% had an IOTN score of 4 or 5. The mean age at the first MDT was 22 years in the first cohort and 21 years and 4 months in the second immediate post-surgery cohort. Of patients, 37.93% had undergone some form of previous orthodontic treatment, but only 0.28% had undergone previous orthognathic treatment; 96.93% had an MDT confirm that orthodontic treatment by itself was insufficient to adequately correct their functional symptoms. The average treatment time from bond up to surgery was 2 years and 6 months. With respect to information provision, patients received information from a number of sources, principally the British Orthodontic Society (BOS) patient information leaflets and the BOS website Your Jaw Surgery. CONCLUSIONS: In the UK, the majority of orthognathic cases fulfil the criteria for acceptance for NHS-funded orthognathic treatment, as outlined by the Chief Dental Officer's interim guidance on orthognathic treatment. This suggests any prior approval process would not be a good use of NHS resources in the commissioning of orthognathic treatment.


Assuntos
Procedimentos Cirúrgicos Ortognáticos , Sociedades Odontológicas , Adulto , Grupos Étnicos , Humanos , Índice de Necessidade de Tratamento Ortodôntico , Inquéritos e Questionários , Adulto Jovem
2.
Am J Orthod Dentofacial Orthop ; 155(6): 767-778, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153497

RESUMO

INTRODUCTION: The aim of this laboratory and randomized clinical trial was to investigate particulate production at debonding and enamel clean-up following the use of flash-free ceramic brackets and to compare them with non-flash-free metal and ceramic brackets. METHODS: In the laboratory study, brackets were bonded to bovine teeth. After 24 hours of immersion in water, the brackets were debonded, the adhesive remnant scores noted, and the enamel cleaned with the use of rotary instruments. Four bracket-adhesive combinations and 2 different enamel pretreatment regimens were tested, including metal and ceramic brackets (conventional, adhesive precoat [APC], and APC flash-free) and conventional acid etch and self-etching primer. Quantitative (mg/m3) and qualitative analysis of particulate production was made in each case. In the clinical trial, 18 patients treated with the use of fixed appliances were recruited into this 3-arm parallel-design randomized controlled trial. They were randomly allocated to 1 of 3 groups: experimental flash-free ceramic bracket or non-flash-free ceramic or metal bracket group. Eligibility criteria included patients undergoing nonextraction maxillary and mandibular fixed appliance therapy. At completion of treatment, the brackets were debonded, and the primary outcome measure was particulate concentration (mg/m3). Randomization was by means of sealed envelopes. Data were analyzed with the use of quantile plots and linear mixed models. The effect of etch, bracket, and stage of debonding of clean-up on particle composition was analyzed with the use of mixed-effects regression. RESULTS: In the laboratory study, the APC brackets produced the highest particulate concentration. Although statistically significantly higher than the metal and conventional ceramic brackets, it was not significantly higher than the ceramic flash-free brackets. In the clinical study, there was no statistically significant effect of bracket type on particulate concentration (P = 0.29). This was despite 3 patients with APC flash-free and 1 patient with conventional Clarity (with 1 bracket) having 1 or more ceramic bracket fracture at debonding requiring removal. No adverse events reported. CONCLUSIONS: Particulates in the inhalable, thoracic, and respirable fractions were produced at enamel clean-up with all bracket types. Although APC and APC flash-free brackets produced the highest concentrations in the laboratory study, there was no difference between any of the brackets in the clinical trial. REGISTRATION: The trial was not registered. FUNDING: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.


Assuntos
Cerâmica/química , Cimentos Dentários/química , Descolagem Dentária/métodos , Aparelhos Ortodônticos Fixos , Braquetes Ortodônticos , Material Particulado/química , Animais , Bovinos , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Propriedades de Superfície
3.
J Orthod ; 45(3): 169-175, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29969080

RESUMO

OBJECTIVES: To evaluate the efficiency and effectiveness of Orthodontic treatment in the National Health Service (NHS) hospitals in England and to identify factors that may be predictive of the duration of Orthodontic treatment and number of patients' visits. DESIGN: Retrospective service evaluation. SETTING: The orthodontic departments of two NHS hospitals. METHODS: The data were collected from the clinical notes, the hospital data base and the pre- and post-treatment study models of 70 patients who were treated with fixed appliances. The pre- and post-treatment models were assessed using the Index of Orthodontic Treatment Need (IOTN) and the Peer Assessment Rating (PAR) index. RESULTS: (1) 98.5% of the patients treated with fixed appliances in both hospitals were in definite need for treatment, (2) The mean percentage PAR score reduction was 81.5%, (3) The mean treatment duration was 27 months with an average of 21 appointments, (4) Factors increasing treatment duration included being a female patient, class I malocclusion, IOTN 5, extractions, prescribing headgear wear, using functional appliances or quadhelixes and increased number of missed appointments, (5) Factors reducing the treatment time were male patients, class II or class III malocclusions and an increased number of emergency appointments. CONCLUSIONS: The hospitals demonstrated a high standard of orthodontic treatment.


Assuntos
Má Oclusão , Ortodontia Corretiva , Feminino , Humanos , Masculino , Estudos Retrospectivos , Atenção Secundária à Saúde , Medicina Estatal , Resultado do Tratamento , Reino Unido
4.
J Prosthet Dent ; 120(3): 476-482, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29627205

RESUMO

STATEMENT OF PROBLEM: The color degradation of maxillofacial prostheses in clinical service requires their frequent renewal. How different materials compare is unclear. PURPOSE: The purpose of this in vitro study was to investigate the color stability of a nonpigmented and pigmented maxillofacial silicone when stored in darkness and exposed to accelerated aging in a weathering chamber and natural outdoor weathering. MATERIAL AND METHODS: M511 elastomer was colored with Spectromatch Pro colorants, stored in darkness, and exposed to accelerated aging and natural outdoor weathering for 1500 hours. Test groups included nonpigmented specimens (n=18), individually pigmented specimens (n=90), and Caucasian skin tone-colored specimens (n=18). The CIELab values of the test specimens were measured using the CM-2600d spectrophotometer (Konica Minolta Sensing) at base line (0 hours) and then every 100 hours up to 1500 hours of aging. Color changes (ΔE) were calculated based on the recorded CIELab values. All data were analyzed by using linear mixed models and the Sídák multiple comparison of means test (α=.05). RESULTS: A significant effect of time was found on the ΔE of all test specimens in all environments (P=.001). All pigmented M511 specimens demonstrated good color stability with maximum ΔE below the acceptability threshold of 2 ΔE when stored in darkness and exposed to outdoor weathering. However, nonpigmented specimens crossed this acceptability threshold when exposed to outdoor weathering with maximum ΔE values of 3.65. The greatest color changes were observed for all specimens when exposed to accelerated aging and most exceeded the acceptability threshold. Nonpigmented (ΔE, 4.86) and Indian yellow (ΔE, 5.20) demonstrated the highest color changes after 1500 hours. CONCLUSIONS: All environments resulted in visible color changes of nonpigmented and pigmented M511 elastomer. The lowest ΔE values were observed for specimens stored in darkness and the greatest for specimens exposed to accelerated aging. The organic pigment Logwood maroon demonstrated the best color stability with maximum ΔE values below the perceptibility threshold (PT) of 1 ΔE.


Assuntos
Cor , Procedimentos Cirúrgicos Bucais , Pigmentação em Prótese , Elastômeros de Silicone , Meio Ambiente , Humanos , Umidade , Técnicas In Vitro , Luz , Elastômeros de Silicone/efeitos da radiação , Luz Solar , Temperatura
5.
Eur J Orthod ; 40(2): 200-205, 2018 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-29016739

RESUMO

Objective: To assess if severity of hypodontia is related to a specific skeletal pattern. Study design: Lateral cephalometric radiographs and dental panoramic tomographs of 182 hypodontia patients were analysed. The severity of hypodontia was recorded and the sample was divided into groups with mild (n = 71), moderate (n = 56) and severe (n = 55) hypodontia. According to ethnicity, the sample was further subdivided into White Caucasians, African-British, and Arabian/Indian subgroups. Cephalometric measurements were used to quantify the skeletal discrepancy and vertical facial dimensions. Mean and standard deviation for each group were obtained for comparison and an analysis of variance (ANOVA) was carried out to assess the level of significance between the means of the readings in different severity groups. Results: In the white Caucasian group, increased severity of hypodontia, was related to a retrusive maxilla with concomitant reduction of A point, Nasion, B point (ANB), reduced mandibular plane angle and anterior lower facial height (P value: 0.0935-0.9371). For the Black-British and Arabian/Indian groups' findings were inconsistent, with no specific pattern as the number of missing teeth increased. Conclusion: The white Caucasian group followed a pattern that has previously been reported in other studies. For Black-British and Arabian/Indian groups' findings were inconsistent and no specific pattern emerged for different degrees of hypodontia.


Assuntos
Anodontia/patologia , Adolescente , Adulto , Grupo com Ancestrais do Continente Africano , Análise de Variância , Anodontia/diagnóstico por imagem , Anodontia/etnologia , Árabes , Cefalometria/métodos , Grupo com Ancestrais do Continente Europeu , Face/patologia , Feminino , Humanos , Masculino , Mandíbula/patologia , Maxila/patologia , Radiografia Panorâmica , Estudos Retrospectivos , Índice de Gravidade de Doença , Dimensão Vertical
6.
J Prosthet Dent ; 119(2): 299-304, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28645662

RESUMO

STATEMENT OF PROBLEM: Conventionally, maxillofacial prostheses are fabricated by hand carving the missing anatomic defect in wax and creating a mold into which pigmented silicone elastomer is placed. Digital technologies such as computer numerical control milling and 3-dimensional (3D) printing have been used to prepare molds, directly or indirectly, into which a biocompatible pigmented silicone elastomer can be placed. PURPOSE: The purpose of this in vitro study was to develop a silicone elastomer that could be 3D printed directly without a mold to create facial or body prostheses by varying its composition. MATERIAL AND METHODS: The room temperature vulcanizing silicone composition was divided into 2 components which were mixed 1:1 to initiate polymerization in the printer before printing began. Different types of moderators and thixotropic agents were used, and the base composition was varied to obtain 11 formulations. The specimens were printed and polymerized from these formulations and tested for tear and tensile strength and hardness. Ten readings of the specimens were recorded for tear and tensile strength and 6 for hardness. Results were analyzed using ANOVA (α=.05). Visual assessment of uncured printed specimens was undertaken for 5 formulations to assess any differences in their ability to hold their shape after printing. RESULTS: The tear and tensile strength of the 11 formulations with varying moderators, thixotropic agents, and base compositions were statistically similar to each other (P>.05). Five of 11 formulations were chosen for the visual assessment as they had sufficient thixotropic agent to avoid slumping while printing. The specimens showed varied slumping behavior until they polymerized. The filler content was increased in the selected formulation, and the tear and tensile strength of the formulation was increased to 6.138 kNm-1 and 3.836 MPa; these increases were comparable to those of commercial silicones currently used for the fabrication of facial prostheses. CONCLUSIONS: The optimum combination of mechanical properties implies the use of one of the formulations as a suitable material for the 3D printing of facial prostheses.


Assuntos
Prótese Maxilofacial , Impressão Tridimensional , Silicones/uso terapêutico , Materiais Biocompatíveis/uso terapêutico , Desenho Assistido por Computador , Técnicas In Vitro , Desenho de Prótese
7.
Am J Orthod Dentofacial Orthop ; 152(6): 744-752, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29173854

RESUMO

INTRODUCTION: The objective of this 4-arm parallel study was to evaluate the alignment efficiency and esthetic performance of 4 coated nickel-titanium archwires over an 8-week period. METHODS: Patients in the permanent dentition requiring maxillary and mandibular fixed orthodontic treatment with a preadjusted edgewise appliance were eligible for inclusion. Patients attending 4 hospital departments (United Kingdom and Italy) were randomly allocated to 1 of 4 treatment interventions: (1) BioCosmetic (Forestadent, Pforzheim, Germany), 0.017 in; (2) Titanol (Forestadent), 0.016 in; (3) TP Aesthetic (TP Orthodontics, La Porte, Ind), 0.014 in; and (4) Tooth Tone (Ortho Organizers, Calsbad, Calif) 0.016 in. Block randomization with block sizes of 4 and 8 was used to ensure an allocation ratio of 1:1:1:1. The primary outcome was alignment efficiency determined by the reduction in Little's irregularity index (mm). Secondary outcomes were color change using the Commission Internationale de L'Eclairage L*a*b* system and percentage of coating loss. Blinding was only applicable to outcome assessment of alignment efficiency. Regression models with Sidak's multiple comparison of means were used to analyze the data. RESULTS: One hundred fifty patients (300 dental arches) were allocated to the treatment interventions, including 61 male and 89 female subjects with a mean age of 16.60 years. The average duration of follow-up was 63.65 days. Baseline characteristics for the archwire groups were similar. One patient was lost to follow-up. Five percent (n = 15) of the archwires fractured: BioCosmetic, 5.3% (n = 4); Titanol, 6.8% (n = 5); TP Aesthetic, 5.3% (n = 4); and Tooth Tone, 2.7% (n = 2). We analyzed 283 dental arches for alignment efficiency. There was no statistically significant difference for mean reduction in irregularity between the archwire groups (P = 0.627): BioCosmetic (n = 71), 3.86 mm (95% CI, 3.31-4.41); Titanol (n = 69), 4.51 mm (95% CI, 4.00-5.02); TP Aesthetic (n = 71), 4.13 mm (95% CI, 3.49-4.78); and Tooth Tone (n = 72), 4.21 mm (95% CI, 3.89-4.46). There was a statistically significant difference between archwire groups for color change (P = 0.001) and percentage of coating loss (P = 0.001), with BioCosmetic performing best in both parameters. CONCLUSIONS: There was no difference between the archwires for alignment efficiency. BioCosmetic performed statistically significantly better than did the other groups for both color change and coating loss. REGISTRATION: This trial was registered with the East Midlands NHS Research Ethics Committee (12/EM/0190). PROTOCOL: The protocol was not published before trial commencement.


Assuntos
Estética Dentária , Níquel , Fios Ortodônticos , Titânio , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Aparelho Ortodôntico , Resultado do Tratamento , Adulto Jovem
8.
J Orthod ; 44(2): 90-96, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28463076

RESUMO

OBJECTIVE: To investigate video content on YouTube™ related to orthognathic surgery. MATERIALS AND METHODS: YouTube™ was searched using the terms: orthognathic surgery; orthodontic surgery; jaw surgery; jaw corrective surgery. Inclusion criteria included English language; primary content orthognathic surgery and acceptable audio-visual quality. Videos were sorted into the top 50 for each search term by view-count and into an overall top 60 from the four searches. The following parameters were recorded for each video: number of views; likes; dislikes; source; primary intention. Each was classified according to information content as 'excellent', 'moderate' or 'poor'. A pre-determined list of orthognathic surgery-related information domains was also evaluated. RESULTS: The top 60 videos had a combined total of 6,986,141 views. Videos predominantly involved patients describing their personal experience (41.67%) with the majority positively biased (61.67%). Only 9.17% of videos were classified as having excellent general information content and 55.83% were rated as poor. Surgical procedures were described in 45% whilst the need for pre- and post-surgical orthodontics was discussed in 33% and 16%, respectively. Post-operative paraesthesia was discussed in 17.5% of videos outcome. CONCLUSIONS: Video content on YouTube™ relating to orthognathic surgery is substandard and patients should be advised to view it with caution.


Assuntos
Cirurgia Ortognática , Procedimentos Cirúrgicos Ortognáticos , Mídias Sociais , Humanos , Internet , Gravação em Vídeo
9.
J Orthod ; 44(1): 8-13, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28248616

RESUMO

INTRODUCTION: The purpose of this study was to evaluate the accuracy of Le Fort I surgery by comparing planned surgical movements with actual outcomes. MATERIALS AND METHODS: A minimum number of seven consecutive cases that had undergone a Le Fort I osteotomy procedure alone or in combination with a mandibular osteotomy from six different hospital units in the East of England between 2009 and 2010 were identified. A total of 56 cases met the inclusion criteria where surgical splints were used and model surgery had been performed. Pre- and post-operative lateral cephalograms were digitised using Dolphin© imaging software (Version 10.0) and three cephalometric points were assessed to measure precision of surgical movements: A point (A-pt); Upper incisor tip (U1 tip); and Upper first molar occlusal point (U6 occ). The final position of the maxilla was compared to the planned position. RESULTS: In 71% of cases surgical movements were within 2 mm and 20% of this group were within 1 mm of the predicted position. The mean accuracy was 1.39 mm (SD 0.92 mm) for the former and 0.78 mm (SD 0.58 mm) for the latter. Accuracy correlated negatively with increased surgical complexity, particularly posterior differential impactions of the maxilla. There was no statistically significant difference between centres. CONCLUSIONS: Pre-operative surgical planning of Le Fort I osteotomies was generally accurate. This study demonstrates that different operators across six centres produced consistent surgical outcomes and this confirms previously reported data.


Assuntos
Maxila , Osteotomia de Le Fort , Cefalometria , Estudos Retrospectivos , Resultado do Tratamento
10.
J Orthod ; 44(2): 105-109, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28300497

RESUMO

OBJECTIVES: The purpose of this in-vitro study was to evaluate the force to debond stainless steel orthodontic brackets bonded to acrylic teeth using different combinations of adhesive and surface treatments. MATERIALS AND METHODS: One hundred prefabricated upper lateral incisor acrylic teeth were divided into 4 equal groups: Transbond XT® adhesive only (Group 1, control), Transbond XT® adhesive with sandblasting (Group 2), Transbond XT® adhesive with abrasion / + methyl methacrylate (MMA) (Group 3) and Triad® Gel only (Group 4). The force in Newtons (N) to debond the brackets was measured. One-way analysis of variance (ANOVA) and pairwise multi-comparison of means (Sidak's adjustment) were undertaken. RESULTS: The highest force to debond was recorded for Group 2 (275.7 N; SD 89.0) followed by Group 3 (241.9 N; SD 76.0), Group 1 (142.7 N; SD 36.7) and Group 4 (67.9 N; SD 21.1). Significant differences in bond strength measurements between the experimental groups were detected. Mean force values for the groups revealed no significant differences between Group 2 and Group 3 (p>0.05). CONCLUSIONS: Both sandblasting and surface abrasion/+ application of methyl methacrylate (MMA) in combination with Transbond XT® adhesive are recommended for bonding stainless orthodontic brackets to acrylic teeth.


Assuntos
Colagem Dentária , Braquetes Ortodônticos , Análise do Estresse Dentário , Teste de Materiais , Cimentos de Resina , Resistência ao Cisalhamento , Aço Inoxidável
11.
Int J Paediatr Dent ; 27(6): 514-522, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28188664

RESUMO

BACKGROUND: Fissure sealants prevent occlusal caries in permanent molars. Enamel preparation methods are used before fissure sealing. AIMS: To investigate effects of bioglass air-abrasion pre-treatment with and without an adhesive, on fissure enamel of permanent teeth, with respect to etchability, microleakage and microtensile bond strength. DESIGN: Half of the occlusal surfaces of 50 extracted premolars underwent bioglass air-abrasion. Dye was applied to the entire occlusal surface. Photographs were taken to score etched surface by dye uptake. Adhesive was applied to 25 of the bioglass-treated areas and all teeth were fissure sealed, sectioned, and evaluated using confocal microscopy. Buccal and lingual surfaces of a further eight premolars were acid-etched and randomly received: air-abrasion, adhesive, both, or none before sealant application for microtensile bond strength measurement in half of the samples immediately and half following 6 months of water immersion. RESULTS: Linear mixed models and multinomial logistic regression were used (P = 0.05). Bioglass air-abrasion significantly improved enamel etchability and reduced microleakage. The addition of an adhesive made no difference to either microleakage or microtensile bond strength. The combination of bioglass abrasion and adhesive led to more cohesive, rather than adhesive, failure. CONCLUSIONS: Bioglass air-abrasion improved enamel etchability and reduced microleakage irrespective of the adhesive use but neither pre-treatment affected the microtensile bond strength.


Assuntos
Condicionamento Ácido do Dente/métodos , Abrasão Dental por Ar , Esmalte Dentário , Selantes de Fossas e Fissuras , Dente Pré-Molar , Esmalte Dentário/diagnóstico por imagem , Fissuras Dentárias , Infiltração Dentária/prevenção & controle , Humanos , Técnicas In Vitro , Teste de Materiais , Propriedades de Superfície
12.
J Orthod ; 43(2): 94-101, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27380483

RESUMO

INTRODUCTION: This retrospective observational cohort study evaluated effectiveness of combined orthodontic-orthognathic surgical treatment in a UK University Dental Institute. METHODS: Patients were identified from a database maintained prospectively throughout a 5-year period of observation. Demographic and clinical data included age, malocclusion, Index of Treatment Need, Index of Orthognathic Functional Treatment Need, orthodontist, surgeon, surgical procedure and treatment-time. Peer Assessment Rating (PAR) scores were generated from pre- and post-treatment dental study casts by a single calibrated examiner. RESULTS: One hundred and sixty two subjects began treatment during the period of observation, 92 completed, 14 elected to discontinue before surgery and 56 remained in treatment. Outcome data were available for 73, 16 males and 57 females (mean age 23.28 [SD, 7.92] years). Within this sample, 33 (45.2%) presented with class II division 1, 6 (8.2%) with class II division 2 and 34 (46.6%) with class III malocclusion. Isolated maxillary and mandibular surgery was carried out in 3 (4.1%) and 24 cases (32.8%), respectively; bimaxillary surgery was performed in 46 (63.1%). Mean total treatment time in fixed appliances was 920.28 days (30.7 months). Mean pre-treatment PAR score was 39.09 [SD, 9.42] and post-treatment 5.86 [SD, 4.25] with a mean 83.7% PAR score reduction, representing a greatly improved occlusal result. Kruskal-Wallis testing found no evidence of any relationship between independent variables and percentage PAR reduction; however, surgeon identity did significantly influence treatment length (P = 0.007). CONCLUSIONS: This investigation demonstrates that in terms of static occlusion combined orthodontic-orthognathic surgery is effective in correcting severe malocclusion.


Assuntos
Má Oclusão/terapia , Ortodontia Corretiva , Adulto , Feminino , Humanos , Masculino , Revisão dos Cuidados de Saúde por Pares , Estudos Retrospectivos , Resultado do Tratamento , Reino Unido , Universidades , Adulto Jovem
13.
J Prosthet Dent ; 116(4): 617-622, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27158034

RESUMO

STATEMENT OF PROBLEM: Conventionally, maxillofacial prostheses are fabricated by hand carving the missing anatomic defect in wax and creating a mold into which pigmented silicone elastomer is placed. Digital technologies such as computer numerical control (CNC) milling and 3-dimensional (3D) printing have been used to prepare molds directly or indirectly into which a biocompatible pigmented silicone elastomer is placed. PURPOSE: The purpose of this in vitro study was to develop a silicone elastomer by varying composition that could eventually be 3D printed directly without a mold to create facial/body prostheses. MATERIAL AND METHODS: The silicone was composed of polydimethylsiloxane (PDMS), filler, catalyst, and cross-linker. Four types of base silicone polymers were prepared with different PDMS molecular weight combinations with long, medium, and short chain length PDMS. The effect of the cross-linker (2.5% to 12.5%) content in these bases was assessed for the effect upon the mechanical properties of the elastomer. Ten readings were made for each formulation, and differences in the means were evaluated with a 2-way ANOVA (α=.05). RESULTS: Variations in silicone composition resulted in hardness from 6.8 to 28.5 durometer, tensile strength from 0.720 to 3.524 kNm-1 and tear strength from 0.954 to 8.484 MPa. Significant differences were observed among all formulations (P<.05). These formulations have mechanical properties comparable with the commercial silicones currently used for the fabrication of facial prostheses. The formulation with 5% cross-linker content and high content of long-chain PDMS chains with optimum mechanical properties was chosen for further development. CONCLUSIONS: The optimum combination of mechanical properties implies the use of one of these formulations for further evaluation in a 3D printer capable of actively mixing and extruding 2-component, room temperature vulcanization silicone.


Assuntos
Dimetilpolisiloxanos/química , Prótese Maxilofacial , Impressão Tridimensional , Materiais Biocompatíveis/uso terapêutico , Reagentes para Ligações Cruzadas/administração & dosagem , Reagentes para Ligações Cruzadas/uso terapêutico , Humanos , Polimerização , Desenho de Prótese/métodos , Silicones/uso terapêutico
14.
J Prosthet Dent ; 115(6): 741-8, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26794701

RESUMO

STATEMENT OF PROBLEM: No universally accepted parameter exists for selecting maxillary central incisors (MCIs) relative to facial proportions. PURPOSE: The purpose of this prospective clinical study was to determine the relationship between MCIs and facial height and width in adults, intersex differences, and measurement differences between right and left MCI. MATERIAL AND METHODS: A prospective study was undertaken of 149 dental students (F:76; M:73) aged between 18 and 30 years. Anthropometric MCI and horizontal and vertical facial measurements were recorded with digital calipers by 1 operator. Correlation was investigated with Pearson correlation coefficients (α=.05). Two-sample t tests were used for intersex comparisons and paired t tests to compare right and left MCIs. Intraexaminer reliability was tested by remeasuring 25 participants and applying the Bland-Altman and Lin analyses. RESULTS: The mean MCI height was 10.28 mm (right and left) and the mean widths were 8.65 mm (right) and 8.66 mm (left). Intersex incisor differences existed for height measurements (M:F 0.54 mm [right], 0.46 mm [left]) and width measurements (M:F 0.26 mm) but not for width-to-height ratios (F=0.85; M=0.84). A mean ratio of 15.56 was found between bizygomatic width:tooth width (M=15.75, F=15.37) and of 17.93 between total face height:MCI height (M=17.97, F=17.89). Correlation coefficients were low for all tooth:face measurements. Intraexaminer reliability was clinically acceptable. CONCLUSIONS: Men had larger teeth and faces but similar width:height ratios. There was no significant size difference between right and left MCI, little individual relationship between tooth:face proportions, and insignificant sex influence. The "biometric ratio"' of 1:16 for MCI:bizygomatic width was not reconfirmed exactly. A ratio of 1:18 is proposed for MCI height to total face height (Tr-Me') and 1:12 for face height (N'-Me').


Assuntos
Face/anatomia & histologia , Incisivo/anatomia & histologia , Maxila/anatomia & histologia , Adolescente , Adulto , Cefalometria , Estética Dentária , Feminino , Humanos , Masculino , Estudos Prospectivos , Fatores Sexuais , Adulto Jovem
15.
Aust Orthod J ; 32(2): 184-192, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29509343

RESUMO

INTRODUCTION: The validity, reliability and inter-method agreement of Peer Assessment Scores (PAR) from acrylic models and their digital analogues were assessed. METHOD: Ten models of different occlusions were digitised, using a 3 Shape R700 laser scanner (Copenhagen, Denmark). Each set of models was conventionally and digitally PAR-scored twice in random order by 10 examiners. The minimum time between repeat measurements was two weeks. The repeatability was assessed by applying Carstensen's analysis. Inter-method agreement (IEMA) was assessed by Carstensen's limit of agreement (LOA). RESULTS: Intra-examiner repeatability (IER) for the unweighted and weighted data was slightly better for the conventional rather than the digital models. There was a slightly higher negative bias of -1 .62 for the weighted PAR data for the digital models. IEMA for the overall weighted data ranged from -8.70 - 5.45 (95% Confidence Interval, CI). Intra-class Correlation Coefficients lICC) for the weighted data for conventional, individual and average scenarios were 0.955 0.906 - 0.986 CI), 0.998 (0.995 - 0.999 CII. ICC for the weighted digital data, individual and average scenarios were 0.99 (0.97 - 1.00) and 1.00. The percentage reduction required to achieve an optimal occlusion increased by 0.4% for the digital scoring of the weighted data. CONCLUSION: Digital PAR scores obtained from scanned plastic models were valid and reliable and, in this context, the digital semi-automated method can be used interchangeably with the conventional method of PAR scoring.


Assuntos
Modelos Dentários , Má Oclusão/diagnóstico , Revisão por Pares , Humanos , Variações Dependentes do Observador , Reprodutibilidade dos Testes
16.
Eur J Orthod ; 38(1): 66-70, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25788331

RESUMO

OBJECTIVES: To assess whether a true knowledge of crowding alters treatment decisions compared with estimates of crowding. MATERIALS AND METHODS: Thirty-six orthodontists were asked to estimate crowding using visualization on eight mandibular arch study models and to indicate possible extraction choices. For each model, the intermolar widths, intercanine widths, and clinical scenarios were identical, but the true crowding varied from 0.2 to 8.4mm as to a lesser extent did the curve of Spee. Eleven orthodontists repeated the visualization exercise after 2 weeks to assess reliability. All 36 of the orthodontists were asked to repeat the treatment planning exercise on the same models, but this time was provided with the true amount of crowding in each case. RESULTS: When the 36 orthodontists used direct visualization of the models to assess crowding, the range of their estimates of crowding increased as the crowding increased. As might be expected, they also tended to move towards extraction treatments as the crowding increased (P = 0.013, odds ratio = 3). Although the reliability of the repeat estimates of crowding were moderate, the mean estimates were greater than the true crowding for each model. When orthodontists were presented with the true amount of crowding, rather than their estimate of crowding, it had a significant effect on the decision to extract, with fewer orthodontists recommending extractions. LIMITATIONS: The principal limitation of this study is that it was a laboratory-based study and utilized just the mandibular arch model for estimation and treatment planning. CONCLUSIONS: Direct visualization may overestimate the amount of crowding present. When the true amount of crowding is known, it can lead to more consistent treatment planning, with the decision to extract fewer teeth in the borderline cases. A formal space analysis is likely to assist with treatment planning.


Assuntos
Competência Clínica , Tomada de Decisão Clínica/métodos , Má Oclusão/diagnóstico , Ortodontia Corretiva/normas , Arco Dental/patologia , Assistência Odontológica , Modelos Dentários , Inglaterra , Humanos , Má Oclusão/patologia , Má Oclusão/terapia , Ortodontia Corretiva/métodos , Planejamento de Assistência ao Paciente , Reprodutibilidade dos Testes , Extração Dentária
17.
J Orthod ; 42(4): 301-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26216658

RESUMO

OBJECTIVES: To compare the accuracy and reproducibility of measurements of on-screen three-dimensional (3D) digital surface models captured by a 3Shape R700™ laser-scanner, with measurements made using a digital caliper on acrylic, plaster models or model replicas. SUBJECTS AND METHOD: Four sets of typodont models were used. Acrylic models, alginate impressions, plaster models and physical replicas were measured. The 3Shape R700™ laser-scanning device with 3Shape™ software was used for scans and measurements. Linear measurements were recorded for selected landmarks, on each of the physical models and on the 3D digital surface models on ten separate occasions by a single examiner. RESULTS: Comparing measurements taken on the physical models the mean difference of the measurements was 0.32 mm (SD 0.15 mm). For the different methods (physical versus digital) the mean difference was 0.112 mm (SD 0.15 mm). None of the values showed a statistically significant difference (p < 0.05) on the Objet Eden 250™ 3D prints, alginate impressions, plaster and acrylic models. CONCLUSION: The comparison of measurements on the physical models showed no significant difference. The 3Shape R700™ is a reliable device for capturing surface details of models in a digital format. When comparing measurements taken manually and digitally there was no statistically significant difference. The Objet Eden 250™ 3D prints proved to be as accurate as the original acrylic, plaster, or alginate impressions as was shown by the accuracy of the measurements taken. This confirms that using virtual study models can be a reliable method, replacing traditional plaster models.

18.
Aust Orthod J ; 31(1): 49-58, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-26219147

RESUMO

BACKGROUND: The present investigation was designed to determine the location and severity of root resorption associated with impacted maxillary canine teeth using cone beam computed tomography (CBCT). A secondary aim was to identify possible influencing factors. METHODS: The radiological reports of 183 patients, radiographed with a small-volume CBCT focussed on the impacted maxillary canine teeth, were assessed. Eighty-five patients had resorption associated with the impaction. The CBCT image datasets were viewed to determine the location and severity of the lesions. RESULTS: A total of 110 impacted maxillary canine teeth resorbed 120 adjacent teeth, including 14 premolars and one permanen molar. The apical third and palatal surface were commonly involved. Fifty per cent of the resorptive lesions were mild, 20% moderate and 30% severe. There was no significant relation between age or gender on the number, location or severity of resorption. There was a statistically significant correlation between the number of impacted canine teeth an'd the number of teeth resorbed, as well as the tooth type and the surface involved in the resorption. CONCLUSIONS: All root levels and surfaces of teeth associated with impacted maxillary canine teeth can be resorbed to different levels of severity. Neither age nor gender influences the number, location or severity of the resorption.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Dente Canino/diagnóstico por imagem , Maxila/diagnóstico por imagem , Reabsorção da Raiz/diagnóstico por imagem , Dente Impactado/diagnóstico por imagem , Adolescente , Adulto , Fatores Etários , Dente Pré-Molar/diagnóstico por imagem , Criança , Estudos Transversais , Polpa Dentária/diagnóstico por imagem , Dentina/diagnóstico por imagem , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Incisivo/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Dente Molar/diagnóstico por imagem , Estudos Retrospectivos , Reabsorção da Raiz/classificação , Fatores Sexuais , Ápice Dentário/diagnóstico por imagem , Adulto Jovem
19.
Eur J Orthod ; 37(1): 49-55, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25086030

RESUMO

AIM: Compare surface roughness of 'aesthetic' nickel-titanium (NiTi) archwires with their dynamic frictional properties. METHODS: Archwires investigated were: four fully coated tooth coloured [Forestadent: Biocosmetic (FB) and Titanol Cosmetic (FT); TOC Tooth Tone (TT); and Hawley Russell Coated Superelastic NiTi (HRC)]; two partially coated tooth coloured [DB Euroline Microcoated (DB) and TP Aesthetic NiTi (TP)]; two rhodium coated [TOC Sentalloy (TS) and Hawley Russell Rhodium Coated Superelastic NiTi (HRR)]; and two controls: stainless steel [Forestadent Steel (FS)] and NiTi archwire [Forestadent Titanol Superelastic (FN)]. Surface roughness [profilometry (Rugosurf)] was compared with frictional coefficients for archwire/bracket/ligature combinations (n = 10). Analysis of variance, Sidak's multiple comparison of means, and Spearman's correlation coefficient were used for analysis. RESULTS: Roughness coefficients were from low to high: FB; FN; TT; FS; TS; HRR; FT; DB; TP; HRC. Friction coefficients were from low to high: TP; FS; FN; HRR; FT; DB; FB; HRC; TS; TT. Coated archwires generally exhibited higher friction than uncoated controls. TP had the lowest friction but this was not statistically significant (P < 0.05). Friction of tooth coloured coated archwires were significantly different for some wires. Spearman's correlation did not demonstrate consistency between surface roughness (R a) and dynamic friction. CONCLUSIONS: Aesthetic archwires investigated had either low surface roughness or low frictional resistance but not both properties simultaneously. Causes for friction are likely to be multifactorial and do not appear to be solely determined by surface roughness (measured by profilometry). For selecting the most appropriate aligning archwire, both surface roughness and frictional resistance need to be considered.


Assuntos
Estética Dentária , Fios Ortodônticos , Fricção , Humanos , Teste de Materiais/métodos , Níquel , Aço Inoxidável , Propriedades de Superfície , Titânio
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