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BACKGROUND: Atherosclerosis and its secondary diseases display a major threat to patient's health. Sequelae, like carotid artery calcification (CAC), usually develop over decades and remain asymptomatic for a long time, making preventive measures to reduce mortality and morbidity extremely important. Through panoramic radiography (PR) and cone beam computed tomography (CBCT), dentists may have helpful tools in aiding the holistic care of patients. In this context, the correlation of atherosclerotic risk factors and CAC development have not yet been sufficiently investigated. Thus, the aim of this observational radiological study was to evaluate the diagnostic value of PR compared with CBCT for the detection of CAC in patients older than 60 years. The radiological findings were correlated with gender, age, and cardiac risk factors. METHODS: PRs and CBCTs of N = 607 patients were used for the qualitative analysis and compared. Basic patient information such as age, gender, body mass index (BMI), smoking history as well as patient's detailed medical history, including heart disease and cardiovascular risk factors such as hypercholesterolemia, arterial hypertension and diabetes mellitus type II were documented and their relation to CAC provided by radiological data was estimated in the form of odds ratios (OR), which were calculated using logistic regression models. Proportions of CAC in different risk groups were compared using Fisher's exact test, the significance level was set to α ≤ 0.05. The interrater reliability of two physicians was estimated using Cohen's kappa. RESULTS: With an accuracy of 90.6%, a sensitivity of 67.5% and a specificity of 99.5% compared to CBCT, PR was a reliable method for the diagnosis of CAC. The overall detection rate for CAC was 27.8% across all age groups. Age (OR: 1.351; p = 0.021), the male sex (OR: 1.645; p = 0.006), arterial hypertension (OR: 2.217; p = < 0.001), heart disease (OR: 1.675; p = 0.006), hypercholesterolemia (OR: 1.904; p = 0.003) and chronic obstructive pulmonary disease (OR: 2.016; p = 0.036) were statistically significant risk factors. When correlated, neither history of stroke nor nicotine abuse showed any statistical significance. CONCLUSIONS: Due to the capabilities of PR in the diagnosis of CAC, dentists can play a vital role in the early diagnosis of vascular disease. Awareness should therefore be raised among dentists regarding the detection of CAC in patients over 60 years of age, with a particular focus on those with arterial hypertension and hypercholesterolaemia.
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Enfermedades Cardiovasculares , Enfermedad de la Arteria Coronaria , Hipercolesterolemia , Hipertensión , Anciano , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Cardiovasculares/epidemiología , Arterias Carótidas , Enfermedad de la Arteria Coronaria/diagnóstico , Enfermedad de la Arteria Coronaria/epidemiología , Factores de Riesgo de Enfermedad Cardiaca , Hipertensión/complicaciones , Hipertensión/epidemiología , Prevalencia , Reproducibilidad de los Resultados , Factores de Riesgo , FemeninoRESUMEN
OBJECTIVES: This retrospective study evaluates intraoral surgical and conservative treatment need in patients with a chronic kidney end-stage disease, depending on the duration of dialysis treatment and the causative nephrological disease. MATERIAL AND METHODS: This study is based on data of patients referred to the Department of Oral and Maxillofacial Surgery of the University Hospital Erlangen, Germany, prior to kidney transplantation between January 2015 and March 2020. The necessity for oral surgical or dental therapy was determined by clinical and radiological examinations. Data on renal replacement therapy, cause of underlying renal disease, lifestyle, and general health were collected. RESULTS: Data of N = 89 patients demonstrated that surgical treatment need depends on dialysis duration (p = 0.042). Patients, who had been dialyzing for 2 to 3 years showed the highest need for surgical intervention (80.0%; p = 0.024), followed by dialysis patients with a dialysis time of more than 3 years (48.1%). Similarly, dialysis patients in the second or third year of dialysis had the highest need for conservative treatment (73.3%; p > 0.05), followed by 55.6% of dialysis patients in the third year of dialysis. CONCLUSIONS: Operative and conservative treatment is essential to optimize subsequent kidney transplantation. The greatest necessity could be detected for patients in the second and third years of dialysis. CLINICAL RELEVANCE: Oral health addressing surgical and conservative treatment need depends on the duration of dialysis in patients with a chronic kidney end-stage disease.
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Fallo Renal Crónico , Trasplante de Riñón , Salud Bucal , Procedimientos Quirúrgicos Orales , Tratamiento Conservador , Alemania , Humanos , Fallo Renal Crónico/cirugía , Trasplante de Riñón/efectos adversos , Diálisis Renal , Estudios Retrospectivos , Factores de TiempoRESUMEN
BACKGROUND: Due to the SARS-CoV-2 pandemic and the accompanying contact restrictions, a new challenge arose for dental education. Despite the limited overall situation, it must be ensured that, in addition to theoretical content, practical skills in particular continue to be taught. Therefore, the aim of this study was to develop and implement an online hands-on course for dental students that ensures practical training, even during the pandemic. METHODS: The newly developed course was held from April 2020 to March 2021. A total of six groups (each consisting of approximately 40-50 students) took part in the course. The participating students were in their 3rd, 4th or 5th year of study. The course taught theoretical basics (via an online platform) and promoted the learning of practical/surgical techniques on models such as bananas, pork bellies, or chicken thighs with live demonstrations (via ZOOM) and interactive post-preparation by students at home (and in a rotating small group of 3-7 students on site). Student self-evaluation (at the beginning and end of the course) and course evaluation were performed using questionnaires. The learning success was analyzed (through self-evaluations) using Wilcoxon signed-rank tests (significance level alpha = 0.05). RESULTS: Concerning students´ self-evaluations, the theoretical knowledge, general surgical skills (such as surgical instrument handling), and specific surgical skills (such as performing a kite flap) improved during the course, with significant results (p < 0.001 for each). About 60% of the students rated the course overall as excellent (grades 9 or 10 on a Likert scale of 1 to 10). The technical implementation of the course was rated with a median of 9 (= very good, on a Likert scale of 1 to 10). 38.5% described the applicability of the skills learned for their later professional life as extremely good. CONCLUSIONS: The results of this work suggest that, within the limitations of this study, the introduced concept of an online hands-on course could be an appropriate form of teaching practical dental skills, even during a pandemic. Further research is needed in the field of digital education for dental students.
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COVID-19 , Educación a Distancia , Educación en Odontología/métodos , Humanos , Aprendizaje , Pandemias , SARS-CoV-2RESUMEN
AIM: This study evaluates the early volumetric changes after buccal soft tissue contour augmentation around implants with a porcine collagen matrix (CM) vs. the subepithelial connective tissue graft (SCTG) from the palate. MATERIALS AND METHODS: 14 patients were enrolled after early implant placement with simultaneous contour augmentation and persistent buccal tissue deficits. At implant exposure, buccal soft tissues were thickened with the CM (n = 7) or the SCTG (n = 7). Impressions were taken before and after surgery, after ten days, one, three and six months. Impressions were digitized and augmented regions 3D evaluated (soft tissue volume (mm3 , %)/thickness (mm)). RESULTS: Volume increase (mm3 ) after 6 months was 19.56 ± 8.95 mm3 (CM) and 61.75 ± 52.69 mm3 (SCTG) (insignificant, p = .058). In percentage, this was a volume loss of the initially augmented soft tissue volume (100%) of 81.76% in the CM group and 56.39% in the SCTG group (6 months). The mean soft tissue thickness increase (mm) in the buccal contour after 6 months was 0.30 ± 0.16 mm (CM) and 0.80 ± 0.61 mm (SCTG) (insignificant, p = .071). CONCLUSION: The early healing phase is associated with a significant volume loss of the soft tissues. The SCTG shows insignificant superiority compared to the CM.
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Implantes Dentales , Encía , Animales , Autoinjertos , Colágeno , Tejido Conectivo , Humanos , PorcinosRESUMEN
BACKGROUND: The aim of this study was to investigate the occurrence of postoperative bleeding following dentoalveolar surgery in patients with either continued vitamin K antagonist medication or perioperative bridging using heparin. METHODS: A retrospective study was performed analyzing patients who underwent tooth extraction between 2012 and 2017. Patients were retrospectively allocated into two comparative groups: un-paused vitamin K antagonist medication versus bridging using heparin. A healthy, non-anticoagulated cohort with equivalent surgery served as a control group. Main outcome measures were: the occurrence and frequency of postoperative bleeding, the number of removed teeth, the surgical technique of tooth removal (extraction/osteotomy/combined extraction and osteotomy) and the prothrombin time. RESULTS: In total, 475 patients were included in the study with 170 patients in the group of un-paused vitamin K antagonist medication VG, 135 patients in the Bridging group BG and 170 patients in the control group CG. Postoperative bleeding was significant: CG versus VG p = 0.004; CG versus BG p < 0.001, BG versus VG p < 0.001. A significant correlation of number of the extracted teeth in the BG (p = 0.014) and no significance in VG (p = 0.298) and CG (p = 0.210) and in the BG versus VG and CG with p < 0.001 in terms of surgical intervention extraction. No difference observed in terms of prothrombin time. CONCLUSIONS: Bridging with heparin increases the risk for bleeding compared to un-paused vitamin K antagonist medication. The perioperative management of anticoagulated patients requires a well-coordinated interdisciplinary teamwork to minimize or at best avoid both: postoperative bleeding and thromboembolic incidences.
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Heparina , Vitamina K , Anticoagulantes/efectos adversos , Humanos , Hemorragia Posoperatoria/epidemiología , Hemorragia Posoperatoria/prevención & control , Estudios RetrospectivosRESUMEN
BACKGROUND: The oral health of organ transplanted patients before organ re-transplantation is largely unknown. This retrospective clinical study evaluates the necessity for intraoral surgical intervention and/or conservative treatment in candidates awaiting organ re-transplantation, both for graft failure and for reasons of another upcoming solid organ transplantation (renal or non-renal). METHODS: From January 2015 to March 2020 n = 19 transplant recipients in evaluation on the waiting list for solid organ re-transplantation could be included in the retrospective case series study. Using clinical and radiological examinations, necessity for oral surgical or conservative dental treatment was evaluated. On the basis of anamnesis data, current kidney function, renal replacement treatment (RRT), and medication, a risk profile for several patient subgroups was created. RESULTS: The clinical and radiological examinations showed a conservative and/or surgical treatment need in n = 13 cases (68.42%). In n = 7 cases (36.84%) surgical intervention was recommended due to residual root remnants (n = 5), unclear mucosal changes (n = 1), and periimplantitis (n = 1). In n = 16 recipients (84.2%) RRT (n = 15 hemodialysis; n = 1 peritoneal dialysis) had been performed. N = 14 recipients (73.68%) received immunosuppressants. In n = 1 patient (5.3%) displayed intraoral and n = 4 patients (21.1%) extraoral neoplasms due to drug-induced immunosuppression. CONCLUSIONS: Solid organ transplant recipients with renal failure present a complex treatment profile due to a double burden of uremia plus immunosuppressants. In cases of surgical treatment need a hospitalized setting is recommended, where potentially necessary follow-up care and close cooperation with disciplines of internal medicine is possible in order to avoid surgical and/or internal complications.
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Fallo Renal Crónico , Trasplante de Riñón , Trasplante de Órganos , Preparaciones Farmacéuticas , Humanos , Fallo Renal Crónico/cirugía , Trasplante de Riñón/efectos adversos , Salud Bucal , Estudios RetrospectivosRESUMEN
BACKGROUND: The abrasion behavior of various ceramics is rarely investigated, though it is relevant for the clinical success of such restorations. The aim of this in vivo study was to evaluate the wear of feldspathic-ceramic-veneered zirconium oxide frameworks over a period of at least 10 years. METHODS: The abrasion behavior of 15 bridge constructions from 15 different participants was examined after a period of 3, 5, and 10 years using plaster models, which were then subjected to a scanning process on the Atos II industrial scanner and digitized for three-dimensional evaluation of the abrasion by the corresponding software (ATOS Professional 7.6). The individual post-examination models were compared to the baseline model and deviations calculated in the sense of the largest, punctual loss of material in millimeters ("minimal distance"), the average abrasion in millimeters ("mean distance"), and the volume decrease in cubic millimeters ("integrated distance"). Statistical analyses were performed using the Wilcoxon sign rank test or mixed regression models. Multiple testing was considered by Benjamini-Hochberg correction. The significance level was set at 0.05. RESULTS: We found steadily increasing wear of the ceramic. The average volume decrease was significant (P < 0.001) at 3 years and 10 years (- 3.25 mm3 and - 8.11 mm3, respectively). CONCLUSIONS: The results of this study indicate that the rate of volume loss in feldspathic-ceramic-veneered zirconia frameworks in the posterior region increases significantly over time. An increasing frequency of parameters was observed, particularly in the second half of the study period. However, the use of this class of materials can be considered clinically acceptable. Trial registration This study is registered in DRKS - German Clinical Trials Register with the register number DRKS00021743. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00021743.
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Porcelana Dental , Circonio , Cerámica , Humanos , Ensayo de Materiales , Propiedades de SuperficieRESUMEN
BACKGROUND/OBJECTIVE: In this retrospective study, we aimed to investigate a new 3D evaluation method for evaluating bone regeneration after cystectomy of odontogenic cysts. METHODS: The study included 26 patients who underwent cystectomies between 2012 and 2017 and had received either fillings or non-fillings with autologous iliac crest. Bony regeneration was analyzed using 3D imaging software and comparing identical regions of interest (ROIs) that were determined by exact overlays of the postoperative cone beam computer tomography (CBCT) or computer tomography (CT) images. Outcome measures, including volume changes according to the defect size and configuration, patient age, the entity and distribution of the cysts, were collected. RESULTS: Twenty-six patients (5 women and 21 men) had 30 defects, including nine keratocysts, seven radicular cysts and 14 dentigerous cysts. A total of 73% of the defects were in the mandible. The mean 3D follow-up time was 12 months. According to the 3D evaluation of bony regeneration, the defect size and configuration showed no significant differences between the groups (filled or non-filled with 15 defects per group). CONCLUSIONS: By establishing a standardized 3D method for evaluating bone regeneration, healing can be better monitored and evaluated.
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Regeneración Ósea/fisiología , Cistectomía , Imagenología Tridimensional/métodos , Quistes Odontogénicos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Autoinjertos , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Ilion/trasplante , Maxilares/diagnóstico por imagen , Masculino , Enfermedades Mandibulares/diagnóstico por imagen , Enfermedades Mandibulares/cirugía , Enfermedades Maxilares/diagnóstico por imagen , Enfermedades Maxilares/cirugía , Persona de Mediana Edad , Quistes Odontogénicos/diagnóstico por imagen , Quistes Odontogénicos/cirugía , Estudios Retrospectivos , Adulto JovenRESUMEN
PURPOSE: Sufficient data are not currently available on how the various geometries of scan bodies and different scan strategies affect the quality of digital impressions of implants. The purpose of this study was to present new data on these two topics and give clinicians a basis for decision making. MATERIALS AND METHODS: A titanium master model containing three Nobelreplace Select™ implants (Nobelbiocare Services AG, Zurich, Switzerland) was digitized using an ATOS industrial noncontact scanner. Digitization was repeated three times with different types of scan bodies integrated into the implants: ELOS A/S, nt-trading GmbH, and TEAMZIEREIS GmbH. These three scans served as virtual master models. The titanium master model was then scanned with the TRIOS3© digital intraoral scanner (ELOS A/S, Copenhagen, Denmark), which was used for two different scanning strategies. Strategy A was a one-step procedure that included both the titanium master model and the integrated scan bodies. Strategy B comprised two steps. First, a digital overlay was performed with a scan of the titanium master model without integrated scan bodies. A second scan was performed with the titanium master model and integrated scan bodies. By repeating both strategies 10 times for each type of scan body, 60 scans were generated and the corresponding standard tessellation language data sets overlaid with the corresponding virtual master model. Deviations in the resulting superimpositions were calculated and evaluated separately in the individual axes (x, y, z) and in three-dimensional space (Euclidean distance). Statistical evaluation was performed using the R-project software. Level of significance was determined at p ≤ 0.05. RESULTS: With regard to the geometry of the scan bodies, strategy A significantly influenced the accuracy of the digital implant impression in regards to Euclidean distance (p = 0.003). No significant difference was found for strategy B in this context. Comparing the two scan strategies revealed that strategy A achieved significantly higher accuracy overall (p = 0.031). CONCLUSION: The quality of digital intraoral impressions seems to be influenced by both the geometry of the scan body and the scan strategy. For clinical practice, the one-step scan strategy seems beneficial. Furthermore, the scan bodies of ELOS A/S showed a potential clinical advantage.
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Implantes Dentales , Técnica de Impresión Dental , Diseño Asistido por Computadora , Materiales de Impresión Dental , Imagenología Tridimensional , Modelos Dentales , SuizaRESUMEN
PURPOSE: To investigate mucoid discharge and the inflammatory response of anophthalmic sockets to cryolite glass prosthetic eye wear. PATIENTS AND METHODS: A total of 101 cryolite glass prosthetic eye wearers used visual analog scales (0-10) to measure frequency, color, volume, and viscosity of mucoid discharge associated with their prosthesis. Standardized photographs of the conjunctiva of their anophthalmic sockets were taken and conjunctival inflammation was semi-quantitatively graded (0-4). All characteristics of discharge and conjunctival inflammation were correlated to eye loss cause, hand washing behavior, and cleaning regimes as explanatory variables. RESULTS: Mean mucoid discharge characteristics (0-10 scale) were frequency 5.3 ± 2.8, color 4.8 ± 3.2, volume 4.9 ± 3.0, and viscosity 5.1 ± 3.2. The mean conjunctival inflammation score (0-4 scale) was 2.1 ± 1.0. There was a positive correlation between the grade of conjunctival inflammation and the frequency (p = 0.018), color (p = 0.001), volume (p = 0.003), and the viscosity of mucoid discharge (p = 0.005). More conjunctival inflammation was associated with higher frequency of cleaning (p < 0.001) and lower frequency of hand washing before removal (p = 0.001). Higher frequency, color, volume, and viscosity of discharge were associated with higher frequency of cleaning (p ≤ 0.001). CONCLUSIONS: Discharge severity associated with prosthetic eye wear was positively correlated with more conjunctival inflammation, higher cleaning frequency, and less hand washing before handling. The results suggest that cryolite glass eyes should not be removed daily for cleaning and that further research should be undertaken to develop a standardized treatment protocol for managing inflammation and mucoid discharge. This protocol would advise hand washing before handling cryolite glass eyes and recommend a minimum period of wear between cleaning sessions.
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Anoftalmos/cirugía , Conjuntivitis/patología , Ojo Artificial , Satisfacción del Paciente , Fluoruro de Sodio , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Enucleación del Ojo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Diseño de Prótesis , Encuestas y Cuestionarios , Adulto JovenRESUMEN
AIM: Deformation of the mandible presents a major challenge for many dentists, both in conventional prosthetic supraconstructions and in complex implant restorations. This study aimed to evaluate the three-dimensional (3D) deformation of the mandible in vivo with scannable impression material and an industrial optical scanner. MATERIALS AND METHODS: In the present study, 20 female and 20 male subjects were examined. In each case, two impressions were made with polyvinylsiloxane: one with the mouth slightly open, and a second with the mouth wide open. The impressions were digitized with an industrial optical scanner and transformed into a virtual model. The two corresponding models were digitally superimposed over all the teeth. Then, an individual local coordinate system was assigned to each individual tooth. Subsequently, a best-fit procedure was performed for each individual tooth. Finally, the open- and closed-mouth models were compared by calculating the differences and rotations in the individual axes. This procedure was performed individually for each tooth. RESULTS: The mean deviations in the x-, y-, and z-coordinates ranged from 0.011 mm at the canines to 0.232 mm at the molars. Larger discrepancies were observed in the female subjects than in the male subjects; however, these differences were not statistically significant. CONCLUSION: The results demonstrated that the posterior region of the mandible deformed when the mouth was maintained in a wide-open position. Therefore, this position should be avoided when performing dental impressions. Moreover, potential negative consequences of this mandibular deformation should be taken into consideration when planning wide-span fixed dental restorations.
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Técnica de Impresión Dental , Modelos Dentales , Materiales de Impresión Dental , Femenino , Humanos , Imagenología Tridimensional , Mandíbula , Diente MolarRESUMEN
PURPOSE: To compare the concerns of experienced cryolite glass and (poly)methyl methacrylate (PMMA) prosthetic eye wearers. METHODS: One hundred six experienced cryolite glass and 63 experienced PMMA prosthetic eye wearers completed an anonymous questionnaire regarding general and specific prosthetic eye concerns at least 2 years after natural eye loss. From these independent anophthalmic populations, we identified 34 case-control pairs matched for the known influencing demographic variables of gender, occupation, age, and time since natural eye loss. RESULTS: The levels of concern were significantly lower in the cryolite glass group than those in the PMMA group for the following: loss of balance (p < 0.001), phantom sight vision (p < 0.001), pain (p < 0.001), receiving good advice (p = 0.001), fullness of orbit (p = 0.001), size (p = 0.007), direction of gaze relative to the healthy fellow eye (p = 0.005), eye lid contour (p = 0.037), comfort of the prosthetic eye (p < 0.001), colour relative to the healthy fellow eye (p < 0.001), and retention of the prosthetic eye (p < 0.001). Concerns about watering, crusting, discharge, visual perception, appearance, movement of the prosthetic eye, and health of the remaining eye were not significantly different between both groups. CONCLUSIONS: The results of this study showed that many general and specific levels of concern were significantly lower for cryolite glass prosthetic eye wearers than for PMMA prosthetic eye wearers. The question of why there are significant differences and to what extent the material of the prosthesis (cryolite glass or PMMA) has an impact on various concerns remains unanswered and should be addressed in a prospective comparative multicentre trial.
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Anoftalmos/psicología , Ojo Artificial , Polimetil Metacrilato , Calidad de Vida , Fluoruro de Sodio , Visión Ocular/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anoftalmos/fisiopatología , Anoftalmos/cirugía , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Encuestas y Cuestionarios , Adulto JovenRESUMEN
OBJECTIVES: This study aimed to identify anatomical areas where resections of oral squamous cell carcinomas (OSCC) are significantly associated with close or positive margins. MATERIALS AND METHODS: This retrospective study included 330 patients with a primary OSCC from 2010 to 2015. Patient and tumour data were categorised into three groups by R-status (R0 [clear], ≥ 5 mm, 185 patients [56.06%]; R1 [positive], < 1 mm, 24 patients [7.27%]; and R0 [close], 1-5 mm, 121 patients [36.67%]). RESULTS: Areas where resections were significantly associated with close or positive margins were the hard palate (p < 0.001), buccal mucosa (p = 0.03), floor of the mouth (p = 0.004), lower alveolar ridge (p = 0.01), retromolar triangle (p = 0.005), and dorsal tongue (p = 0.02). CONCLUSIONS: Anatomical areas were identified in the oral cavity where it is challenging to resect OSCCs with an adequate safety margin. CLINICAL RELEVANCE: These results may enable surgeons to achieve a postulated safe distance during tumour resection, leading to a survival benefit for patients.
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Carcinoma de Células Escamosas/cirugía , Márgenes de Escisión , Neoplasias de la Boca/cirugía , Puntos Anatómicos de Referencia , Carcinoma de Células Escamosas/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Boca/patología , Clasificación del Tumor , Estadificación de Neoplasias , Estudios RetrospectivosRESUMEN
STATEMENT OF PROBLEM: Accurate virtual implant models are a necessity for the fabrication of precisely fitting superstructures. PURPOSE: The purpose of this in vitro study was to evaluate different methods with which to build an accurate virtual model of a 3-dimensional implant in the oral cavity; this model would then be used for iterative computer-aided design and computer-aided manufacturing (CAD-CAM) procedures. MATERIAL AND METHODS: A titanium master model with 3 rigidly connected implants was manufactured and digitized with a noncontact industrial scanner to obtain a virtual master model. Impressions of the master model with the implant position locators (IPL) were made using vinyl siloxanether material. The impressions were scanned (Impression scanning technique group). For the transfer technique and pick-up technique groups (each group n=20), implant analogs were inserted into the impression copings, impressions were made using polyether, and casts were poured in Type 4 gypsum. The IPLs were screwed into the analogs and scanned. To compare the virtual master model with each virtual test model, a CAD interactive software, ATOS professional, was applied. The Kruskal-Wallis test was subsequently used to determine the overall difference between groups, with the Mann-Whitney U test used for pairwise comparisons. Through Bonferroni correction, the α-level was set to .017. RESULTS: The outcome revealed a significant difference among the 3 groups (P<.01) in terms of accuracy. With regard to total deviation, for all axes, the transfer technique generated the greatest divergence, 0.078 mm (±0.022), compared with the master model. Deviation with the pick-up technique was 0.041 mm (±0.009), with impression scanning generating the most accurate models with a deviation of 0.022 mm (±0.007). CONCLUSIONS: The impression scanning method improved the precision of CAD-CAM-fabricated superstructures.
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Técnica de Impresión Dental , Diseño de Prótesis Dental/métodos , Diseño Asistido por Computadora , Implantes Dentales , Prótesis Dental de Soporte Implantado/métodos , Humanos , Imagenología Tridimensional/métodos , Técnicas In Vitro , Reproducibilidad de los ResultadosRESUMEN
The purpose of our study was to investigate the antibacterial effect of a spacer (Ti6Al4V) coated with 4x Cu-TiO2 in an animal model simulating an acute periprosthetic infection by Staphylococcus aureus. Ti6Al4 bolts contaminated with Staphylococcus aureus were implanted into the femoral condyle of rabbits (n = 36) divided into 3 groups. After one week in group 1 (control) the bolts were removed without any replacement. In group2 Ti6Al4V bolts with a 4x Cu-TiO2 coating and in group 3 beads of a gentamicin-PMMA chain were imbedded into the borehole. Microbiological investigation was performed at the primary surgery, at the revision surgery and after scarification of the rabbits 3 weeks after the first surgery. Blood tests were conducted weekly. The initial overall infection rate was 88.9%. In group 2 and 3 a significant decrease of the infection rate was shown in contrast to the control group. The C-reactive protein (CRP) levels declined one week after the first surgery except in the control group where the CRP level even increased. This is the first in vivo study that demonstrated the antibacterial effects of a fourfold Cu-TiO2 coating. For the future, the coating investigated could be a promising option in the treatment of implant-associated infections.
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Antibacterianos/uso terapéutico , Materiales Biocompatibles Revestidos , Cobre , Modelos Animales de Enfermedad , Prótesis e Implantes/microbiología , Infecciones Estafilocócicas/tratamiento farmacológico , Titanio , Enfermedad Aguda , Aleaciones , Animales , Fémur , Diseño de Prótesis , Conejos , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificaciónRESUMEN
The protection of sensitive structures (e.g., nerves) from iatrogenic damage is of major importance when performing laser surgical procedures. Especially in the head and neck area both function and esthetics can be affected to a great extent. Despite its many benefits, the surgical utilization of a laser is therefore still limited to superficial tissue ablation. A remote feedback system which guides the laser in a tissue-specific way would provide a remedy. In this context, it has been shown that nerval structures can be specifically recognized by their optical diffuse reflectance spectra both before and after laser ablation. However, for a translation of these findings to the actual laser ablation process, a nerve protection within the laser pulse is of utmost significance. Thus, it was the aim of the study to evaluate, if the process of Er:YAG laser surgery--which comes with spray water cooling, angulation of the probe (60°) and optical process emissions--interferes with optical tissue differentiation. For the first time, no stable conditions but the ongoing process of laser tissue ablation was examined. Therefore, six different tissue types (nerve, skin, muscle, fat, cortical and cancellous bone) were acquired from 15 pig heads. Measurements were performed during Er:YAG laser ablation. Diffuse reflectance spectra (4500, wavelength range: 350-650 nm) where acquired. Principal component analysis (PCA) and quadratic discriminant analysis (QDA) were calculated for classification purposes. The clinical highly relevant differentiation between nerve and bone was performed correctly with an AUC of 95.3% (cortial bone) respectively 92.4% (cancellous bone). The identification of nerve tissue against the biological very similar fat tissue yielded good results with an AUC value of 83.4% (sensitivity: 72.3%, specificity: of 82.3%). This clearly demonstrates that nerve identification by diffuse reflectance spectroscopy works reliably in the ongoing process of laser ablation in spite of the laser beam, spray water cooling and the tissue alterations entailed by tissue laser ablation. This is an essential step towards a clinical utilization.
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Tejido Conectivo/inervación , Nervio Facial/patología , Nervio Facial/cirugía , Terapia por Láser , Animales , Tejido Conectivo/patología , Tejido Conectivo/cirugía , Huesos Faciales/inervación , Huesos Faciales/patología , Músculos Faciales/inervación , Músculos Faciales/patología , Músculos Faciales/cirugía , Terapia por Láser/efectos adversos , Terapia por Láser/instrumentación , Terapia por Láser/métodos , Láseres de Estado Sólido , Fenómenos Ópticos , Procedimientos Quirúrgicos Orales/efectos adversos , Procedimientos Quirúrgicos Orales/métodos , Sensibilidad y Especificidad , Piel/inervación , Piel/patología , PorcinosRESUMEN
BACKGROUND: In the field of oral and maxillofacial surgery, newly developed laser scalpels have multiple advantages over traditional metal scalpels. However, they lack haptic feedback. This is dangerous near e.g. nerve tissue, which has to be preserved during surgery. One solution to this problem is to train an algorithm that analyzes the reflected light spectra during surgery and can classify these spectra into different tissue types, in order to ultimately send a warning or temporarily switch off the laser when critical tissue is about to be ablated. Various machine learning algorithms are available for this task, but a detailed analysis is needed to assess the most appropriate algorithm. METHODS: In this study, a small data set is used to simulate many larger data sets according to a multivariate Gaussian distribution. Various machine learning algorithms are then trained and evaluated on these data sets. The algorithms' performance is subsequently evaluated and compared by averaged confusion matrices and ultimately by boxplots of misclassification rates. The results are validated on the smaller, experimental data set. RESULTS: Most classifiers have a median misclassification rate below 0.25 in the simulated data. The most notable performance was observed for the Penalized Discriminant Analysis, with a misclassifiaction rate of 0.00 in the simulated data, and an average misclassification rate of 0.02 in a 10-fold cross validation on the original data. CONCLUSION: The results suggest a Penalized Discriminant Analysis is the most promising approach, most probably because it considers the functional, correlated nature of the reflectance spectra.The results of this study improve the accuracy of real-time tissue discrimination and are an essential step towards improving the safety of oral laser surgery.
Asunto(s)
Traumatismos del Nervio Facial/prevención & control , Terapia por Láser/métodos , Imagen Óptica/métodos , Análisis Espectral/métodos , Cirugía Bucal/métodos , Algoritmos , Inteligencia Artificial , Simulación por Computador , Análisis Discriminante , Retroalimentación , Humanos , Tejido Nervioso/lesiones , Análisis de Componente PrincipalRESUMEN
The aim of this study was the investigation of a copper-filled TiO2 coating, that in vitro showed good antibacterial properties combined with good tissue tolerance in an animal model. To better understand the antibacterial mechanism of the bioactive coating the release of copper (Cu) ions over time was monitored to be able to detect possible threats as well as possible fields of application. 30 New Zealand White rabbits were divided into two groups with 15 animals per group. In group 1 (control group) Ti6Al4 V bolts were implanted into the distal femur, in group 2 the Ti6Al4 V bolts were coated with four TiO2-coatings with integrated Cu(2+)-ions (4 × Cu-TiO2). Blood tests were performed weekly until the animals were sacrificed 4 weeks postoperative. The maximum peak of Cu and ceruloplasmin concentration could be seen in both groups one week postoperative, whereas the Cu values in group II were significantly higher. The Cu concentration in both groups approximated the initial basic values 4 weeks postoperative. The 4 × Cu-TiO2 coating tested in our rabbit model for total knee arthroplasty is an active coating that releases potentially antibacterial Cu(2+) for 4 weeks with a peak 1 week postoperative. The bioactive coating could be a promising approach for a use in the field of implant related infection, orthopaedic revision and tumor surgery in the future.
Asunto(s)
Materiales Biocompatibles Revestidos/química , Materiales Biocompatibles Revestidos/síntesis química , Cobre/administración & dosificación , Cobre/química , Fémur/cirugía , Prótesis de la Rodilla , Titanio/química , Animales , Antibacterianos/administración & dosificación , Antibacterianos/química , Tornillos Óseos , Implantes de Medicamentos/administración & dosificación , Implantes de Medicamentos/química , Fémur/patología , ConejosRESUMEN
Facial nerve function may be hampered by iatrogenic damage during head and neck laser surgery procedures. Optical techniques can serve as a basis for feedback-controlled tissue-specific laser surgery on the jaw bone and the parotid gland. In order to preserve nerve tissue during laser surgery, the alteration of optical tissue properties through laser-tissue interactions have to be taken into account. It was the aim of this study to evaluate the viability of optical tissue differentiation through diffuse reflectance spectroscopy after exposure to laser light as a basis for a feedback system for tissue-specific laser surgery. Spectra of diffuse reflectance (wavelength, 350-650 nm) of nerves, salivary glands, and cortical and cancellous bone of the midfacial region (ex vivo domestic pig heads) were acquired before/after Er:YAG laser (wavelength, 2.94 µm) ablation (each 16,800 spectra). Principal component analysis was computed followed by quadratic discriminant analysis. The tissue classification performance as well as area under the curve (AUC) sensitivity and specificity for tissue differentiation was assessed before and after laser-tissue exposure. A high classification performance was observed before laser ablation (total error, 7.74%). Nerve tissue was differentiated from bone and salivary glands with results greater than 0.96 in AUC, sensitivity and specificity. After laser exposure, a total classification error of 18.61% was observed. The differentiation of nerve tissue was reduced with an AUC of >0.94, sensitivity of >0.95, and specificity >0.87. Er:YAG laser ablation only slightly reduces the differentiation performance through diffuse reflectance in the investigated tissue types. The results show the general viability of diffuse reflectance spectroscopy in identifying neural structures in the vicinity of salivary glands and bone as a basis for nerve preservation during feedback-controlled laser surgery.
Asunto(s)
Cabeza/cirugía , Terapia por Láser/métodos , Láseres de Estado Sólido , Cuello/cirugía , Nervio Óptico/cirugía , Animales , Área Bajo la Curva , Análisis de Componente Principal , Análisis Espectral , Sus scrofaRESUMEN
The marginal accuracy of fit between prosthetic restorations and abutment teeth represents an essential aspect with regard to long-term clinical success. Since the final gap is also influenced by the luting techniques and materials applied, this study analyzed the accuracy of the fit of single-tooth zirconia copings before and after cementation using different luting materials. Forty plaster dies with a corresponding zirconia coping were manufactured based on a single tooth chamfer preparation. The copings were luted on the plaster dies (n = 10 per luting material) with a zinc phosphate (A), glass-ionomer (B), self-adhesive resin (C), or resin-modified glass-ionomer cement (D). The accuracy of fit for each coping was assessed using a non-destructive digital method. Intragroup statistical analysis was conducted using Wilcoxon signed rank tests and intergroup analysis by Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Accuracy of fit was significantly different before/after cementation within A (0.033/0.110 µm) and B (0.035/0.118 µm; p = 0.002). A had a significantly increased marginal gap compared to C and D, and B compared to C and D (p ≤ 0.001). Significantly increased vertical discrepancies between A and B versus C and D (p < 0.001) were assessed. Of the materials under investigation, the zinc phosphate cement led to increased vertical marginal discrepancies, whereas the self-adhesive resin cement did not influence the restoration fit.