Digital repair for a patient with limited mouth opening: a case report and literature review / 口腔疾病防治

Objective@#To explore an accurate method to obtain an intraoral model of patients with specific limited mouth opening (microstomia) due to systemic scleroderma.@*Methods@#This study followed medical ethics, and informed consent has been obtained from patients. A case of Ken's Type I mandibular dentition defect scleroderma with limited mouth opening was addressed with digital technology as the leading method combined with the traditional impression method of segmental impression. Individual trays were made based on the patient's left and right mandibular dentition, and segmented molds were obtained. Simultaneously, intraoral scanning was performed to obtain the morphological data of both the soft and hard tissues of the upper and lower mandibles. After each part of the model was obtained, the mandibular model was scanned and digitally aligned to form the final denture model, and the final removable partial denture was designed and made by computer aided design/computer aided manufacturing (CAD/CAM) technology. At the same time, combined with the literature, the diagnosis and treatment of removable partial denture in patients with limited mouth opening were retrospectively analyzed.@*Results@#The denture was well retained and achieved a good repair effect. The patients expressed satisfaction with the mastication efficiency and other functions of the denture. The findings of the literature review show that the integration of digital technology with the traditional impression method, along with computer fitting, can accurately obtain the patient's oral model and facilitate successful follow-up repairs. However, when the anterior mandibular dentition of the patient is absent, the margin of error is increased in this procedure, which deserves further exploration.@*Conclusion@#Utilizing digital technology as the leading method, combined with the traditional impression method of segmental impression, for the repair of dental defects in patients with limited mouth opening, has proven to be effective. Thus, patients report a positive medical experience with high satisfaction, indicating that this approach is worthy of clinical promotion.

Comparing the efficacy of sodium hyaluronate eye drops and carboxymethylcellulose eye drops in treating mild to moderate dry eye disease

Purpose: Aim of this study was to compare the efficacy of sodium hyaluronate (SH) and carboxymethyl cellulose (CMC) eye drops in treating mild to moderate dry eye disease in terms of relief of symptoms, mean change in tear film breakup time, Schirmer’s test, and impression cytology of conjunctiva from baseline. Methods: An observational study was carried out during a 2?year period in our tertiary referral hospital. The study consisted of 60 patients randomly allotted to two groups to receive SH and CMC eye drops for an 8?week period. Ocular surface disease index, tear film breakup time, and Schirmer’s test were performed at baseline visit and 4 and 8 weeks of treatment, and impression cytology of conjunctiva was performed at baseline and 8 weeks. Results: Significant improvement in patient symptoms, tear film breakup time, and Schirmer’s test from baseline was seen in both SH and CMC groups at 8 weeks posttreatment, whereas impression cytology of conjunctiva in both groups did not show significant improvement at 8 weeks of treatment. Data analysis using unpaired t?test showed comparable results. Conclusion: Both CMC and SH demonstrated equal efficacy in treating mild to moderate dry eye disease.

Prevalence of dry eye, its categorization (Dry Eye Workshop II), and pathological correlation: A tertiary care study

Purpose: To study the prevalence of dry eye disease (DED), further categorize using DEWS II protocol, grade squamous metaplasia in each group, and determine associated risk factors in a tertiary care hospital. Methods: This cross?sectional hospital?based study screened 897 patients ?30 years via systematic random sampling. Patients with both symptoms and signs as defined by the Dry Eye Workshop II protocol were considered as DED, further categorized, and subjected to impression cytology. Categorical data were assessed using the Chi?square test. P value < 0.05 was considered statistically significant. Results: In total, 265 (of 897) patients were defined as DED based on the presence of symptoms (DEQ?5 ?6) and at least one positive sign (fluorescein breakup time [FBUT] <10 s or OSS ?4). DED prevalence was thus 29.5% with aqueous deficient dry eye (ADDE), evaporative dry eye (EDE), and mixed type seen in 92 (34.71%), 105 (39.62%), and 68 (25.7%) patients, respectively. The risk of developing dry eye was higher in the age above 60 years (33.74%) and in the third decade. Females, urban dwellers, diabetics, smokers, history of previous cataract surgery, and usage of visual display terminal devices were found to be significantly associated with risk factors of DED. Squamous metaplasia and goblet cell loss were more severe in mixed compared to EDE and ADDE. Conclusion: Hospital?based prevalence of DED is 29.5% with a preponderance of EDE (EDE 39.62%, ADDE 34.71%, and mixed 25.71%). A higher grade of squamous metaplasia was seen in the mixed type compared to other sub?types.

Factors influencing the accuracy of intraoral impression in implant restoration / 口腔疾病防治

@#Due to advances in digital technology, intraoral impressions have been increasingly used to fabricate implant restorations because of its simplicity, high efficiency, comfortableness and convenience. In clinical practice, the accuracy of intraoral impressions depends on various factors, including scanner technique, status of dentition and implants, auxiliary devices, materials and environment, which might influence its accuracy and limit its application. When applied to patients missing more teeth, its accuracy may be insufficient. It is suggested that intraoral impressions be used cautiously when there are multiple and far apart implants and that the scan body not be tightened excessively and that maintain appropriate environmental conditions. In this article, we have reviewed recent relevant literature and the factors affecting the accuracy of intraoral impressions for implant restoration.

Application of polyetheretherketone (PEEK) posts: evaluation of fracture resistance and stress distribution in the root: in vitro and finite element analyses

Abstract To evaluate the feasibility of using a milled polyetheretherketone (PEEK) post and core in endodontically treated teeth with or without a ferrule. Sixty bovine tooth roots were endodontically treated followed by cementation of intraradicular retainers (IR), according to each experimental group: a) non-ferrule glass fiber post (f0FP); b) 2-mm-ferrule glass fiber post (f2FP); c) non-ferrule resized glass fiber post (f0PR); d) 2-mm-ferrule resized glass fiber post (f2PR); e) non-ferrule PEEK post and core (f0PPC); and f) 2-mm-ferrule PEEK post and core (f2PPC). Metal crowns were made and cemented. A periodontal ligament was simulated using polyether. A force was applied to the palatine portion of each sample at 45°, until fracture. Fracture resistance data were submitted to two-way ANOVA and Tukey's test (α = 0.05). Three-dimensional digital models were developed to calculate the tensions formed in the root using finite element analysis. Models of glass fiber posts and PEEK posts and cores were evaluated with or without a ferrule. The results were analyzed by the Mohr-Coulomb criterion. The type of IR was not influenced by fracture strength (p = 0.243). There were significant statistical differences among the remaining factors. Ferrule groups had greater fracture resistance, and the failure mode of teeth with a ferrule was more catastrophic than the non-ferrule group. A ferrule increases fracture resistance and influences failure mode; the PEEK post and core did not modify the biomechanics of endodontically treated teeth, and resembled the glass fiber post results. The crack initiation point differed between the ferrule and non-ferrule groups.

Implant digital impression accuracy using extraoral scanners: a three-dimensional analysis

Aim: To analyze the accuracy of extraoral systems (Ceramill Map400+, AutoScan-DS200+, and E2) in full implantprosthetic rehabilitation three-dimensionally. Methods: A metallic edentulous maxilla with four implants was digitalized by a contact scanner (MDX-40 - Roland, control) and used as a control image to compare with other images generated by three laboratory scanners (10 samples per group). Letters identified all the four components: A and D angled 45º, and B and C parallel. The BioCAD software exported the images (.STL) to compare and verify deviations of the analogs on the X, Y, and Z axes. The nonparametric Kruskal-Wallis test and the two-way ANOVA on ranks with a post hoc Tukey test analyzed the data with 5% significance. Results: No statistical differences were observed in the accuracy between the extraoral scanners (p=0.0806). However, when analyzing only the components, component D was more accurate when scanned with Ceramill Map400+ compared with AutoScan DS200+ (p<0.001) and with E2 (p=0.002). Conclusions: All extraoral systems assessed showed digitalization accuracy but with more deviations in angled implants. The Ceramill Map400+ scanner showed the best results for the digital impression of a complete arch

Comparison of efficacy of Gabapentin versus Pregabalin in patients of painful diabetic peripheral neuropathy – A randomized, open label, and parallel group study

Background: Diabetes is a form of chronic illness requiring a collective treatment approach such as glycemic monitoring, self-management, education, and adequate support to prevent the occurrence of acute complications. One of the most frequently occurring complication in Type 2 diabetes has been diabetic peripheral neuropathy (DPN) or distal symmetrical polyneuropathy. Newer anticonvulsants such as Gabapentin and Pregabalin have been proven beneficial in patients with peripheral neuropathic pain. Aims and Objectives: The aim of the study was to compare the efficacy of Gabapentin and Pregabalin in relieving the pain in patients of DPN. Materials and Methods: This is an open label, randomized, multi-dose, two treatment, single-period, single-center, parallel study comparing Gabapentin and Pregabalin for efficacy in patients suffering with DPN using visual analog scale, daily sleep interference score, patient’s global impression of change, and clinician’s global impression of change. Results: One hundred patients were randomized into two groups and the treatment started as and when they reported to the hospital. Statistical analysis was done in SPSS version 23 and intent to treat principle is employed for analysis. Results were distributed in demographics and treatment comparison. Decreased sleep interference and global impression of change reported during first visit, in which participants under Pregabalin group had better improvement score comparing Gabapentin group alone was found statistically significant (P < 0.05). Conclusion: Our study revealed that Pregabalin is found to be more efficacious when compared to Gabapentin among Type 2 diabetes mellitus patients with painful peripheral neuropathy. Hence, we conclude that Pregabalin provided significant improvement in pain relief and other perspectives.

Analytical Study of Ocular Surface Changes in Patients of Chronic Kidney Disease undergoing Hemodialysis and Peritoneal Dialysis

Objectives?The idiopathic group is a significant cause of chronic kidney disease (CKD) in developing countries. Literature available on ocular surface changes has predominantly been reported in patients undergoing hemodialysis. Little is known about the changes in patients undergoing peritoneal dialysis. The present study aimed to identify ocular surface changes in an idiopathic group of CKD undergoing dialysis. Aim?To compare tear film disorders and the severity of ocular surface changes (goblet cell density, squamous metaplasia, and corneoconjunctival calcification) in patients of idiopathic etiology with CKD undergoing hemodialysis and peritoneal dialysis. This is an analytical study. Materials and Methods?Asymptomatic adult patients of idiopathic CKD, on treatment with dialysis underwent comprehensive ophthalmic examination, including best-corrected visual acuity, slit-lamp examination, and a dilated fundus examination. Dry eye assessment was done by ocular surface staining score, Schirmer test, and tear breakup time (TBUT). Conjunctival impression cytology was studied to assess changes on ocular surface. Chest X-rays for aortic calcification were reviewed and data analyzed. Results?Both eyes of 76 patients of hemodialysis and 32 patients of peritoneal dialysis were studied. Ocular surface staining (OSS) scores were low. Impression cytology showed a drop in goblet cell density, presence of squamous metaplasia, and conjunctival keratinization significantly more in the hemodialysis group. No correlation was seen between the presence of conjunctival calcification and aortic calcification. Conclusion?The hemodialysis group had mild subclinical dry eye but keratinization of conjunctiva was seen. Similarly, advanced squamous metaplasia was seen in the peritoneal dialysis group. These changes were positively correlated to decrease in goblet cell density.

Application of a metal occlusal surface and split framework in the treatment of a patient with mandibular distal extension absence and insufficient occlusogingival distance / 口腔疾病防治

Objective@# To investigate the effect of a metal occlusal surface and stress interruption design on minimally invasive prosthodontics for patients with distal extension absence and insufficient occlusal gingival distance.@*Methods @# We retrospectively studied the case of minimally invasive prosthodontic (Vitallium 2000) combined with a metal occlusal surface for distal extension absence in a patient with insufficient occlusal gingival distance; the stress breaking design and pressure impression technology are examined, and relevant articles are reviewd. @*Results@#The design effectively solves the problems of insufficient occlusal gingival distance, large occlusal force and easy denture fracture. Reviewing the relevant literature, stress interruption design can effectively protect abutment teeth, but the behavior of stress interruption design and stress conduction phenomena in the mouths of patients has not been reported. The T-scan test results of this study showed that before and after wearing the denture, the occlusal force distribution ratio of the patient changed from 77.5% on the left and 22.5% on the right to 61.3% on the left and 38.7% on the right. The occlusal force distribution ratio of the right dentition to the total occlusal force increased by 16.2%, and the occlusal force became better distributed. Further analysis showed that the occlusal forces on the left and right sides were nearly the same in the initial occlusion stage. As the occlusal force was further increased, the proportion of the occlusal force on the right side decreased in the middle of the occlusion stage and further decreased in the final occlusion stage until it reached a dynamic balance. The above T-scan test and literature review results suggest that this dynamic balance phenomenon of bite force is related to the stress interruption design and the stress conduction effect of the split framework.@* Conclusion @#The composite of stress interruption design and metal occlusal surface allows for minimally invasive prosthodontics for the treatment of distal extension absence in patients with insufficient occlusal gingival distance.

Application evaluation of prefabricated rigid connecting bar in implants immediate impression preparation of edentulous jaw / 北京大学学报(医学版)

OBJECTIVE@#To compare the operation complexity and accuracy of traditional splint impression technique and impression technique with prefabricated rigid connecting bar system for full-arch implants-supported fixed protheses in vitro.@*METHODS@#Standard mandibular edentulous model with six implant analogs was prepared. The implants were placed at the bone level and multiunit abutments screwed into the implants. Two impression techniques were performed: the traditional splint impression technique was used in the control group, and the rigid connecting bar system was used in the test group. In the control group, impression copings were screwed into the multiunit abutments and connected with autopolymerizing acrylic resin. Open tray impression was fabricated with custom tray and polyether. In the test group, cylinders were screwed into the multiunit abutments. Prefabricated rigid bars with suitable length were selected and connected to the cylinders with small amount of autopolymerizing acrylic resin, and open tray impression was obtained. Impression procedures were repeated 6 times in each group. The working time of the two impression methods were recorded and compared. Analogs were screws into the impressions and gypsum casts were poured. The gypsum casts and the standard model were transferred to stereolithography (STL) files with model scanner. Comparative analysis of the STL files of the gypsum casts and the standard model was carried out and the root mean square (RMS) error value of the gypsum casts of the control and test groups compared with the standard model was recorded. The trueness of the two impression techniques was compared.@*RESULTS@#The work time in the test group was significantly lower than that in the control group and the difference was statistically significant [(984.5±63.3) s vs. (1 478.3±156.2) s, P < 0.05]. Compared with the standard model, the RMS error value of the implant abutments in the test group was (16.9±5.5) μm. The RMS value in the control group was (20.2±8.0) μm. The difference between the two groups was not significant (P>0.05).@*CONCLUSION@#The prefabricated rigid connecting bar can save the chair-side work time in implants immediate loading of edentulous jaw and simplify the impression process. The impression accuracy is not significantly different from the traditional impression technology. The impression technique with prefabricated rigid connecting bar system is worthy of clinical application.

Analyze on the value of conjunctival impression cytology in the diagnosis of allergic conjunctivitis / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the value of conjunctival impression cytology(CIC)in the diagnosis of allergic conjunctivitis(AC). <p>METHODS: A case-control study. Forty patients(80 eyes)who were clinically diagnosed with AC in our department from January to February 2021 were included in the study,and 40 normal controls(80 eyes)were enrolled too. All subjects underwent double upper palpebral CIC examinations. Observed the morphology and number of conjunctival eosinophils and carried out Tseng classification in each group. To Compare the differences between the results of the two groups and analyze the effects of gender, age and course of disease on the results of CIC eosinophil examination in AC group.<p>RESULTS: The positive rate of eosinophils in the upper palpebral CIC examination of AC patients was significantly higher than that of the normal control group(χ²=57.744, <i>P</i><0.001); The Tseng grade of AC patients was also higher than that of the normal control group(<i>Z</i>=-2.453, <i>P</i><0.05). Gender, age and course of disease had no significant effect on the results of CIC eosinophils in AC group(all <i>P</i> >0.05).<p>CONCLUSION: CIC examination is simple, and the result is objective and accurate. It has good application value in the diagnosis of AC.

Apexificación en una cita utilizando material biocerámico como tapón apical / Apexification in a single appointment using a bioceramic material as an apical plug

El objetivo fue realizar una técnica de apexificación en una cita, evaluando clínica y radiográficamente la formación de barrera dura apical, con seguimiento a nueve meses, al utilizar material biocerámico en dien-tes permanentes jóvenes. Se trataron 30 incisivos su-periores permanentes con ápice abierto y anteceden-tes de trauma, en pacientes de ambos géneros y 18-40 años. Las piezas (n=30) se dividieron en dos grupos (n=15). Grupo experimental: tratamiento de apexifica-ción con EndoSequence Root Repair Material (EERR), y grupo control: tratamiento con impresión apical. Se determinaron distribuciones de frecuencias y esta-dísticas descriptivas para cada variable, según es-cala de medición y distribución. Se realizaron IC 95%, test de Chi cuadrado con cálculo de residuos estan-darizados ajustados y test de Fisher. Se fijó nivel de significación p=0.05. Las diferencias de manifestacio-nes preoperatorias y postoperatorias según grupo fueron no significativas (p Fisher = 0.9140) y (p Fisher = 0.992), respectivamente. No se hallaron diferencias entre proporciones de hallazgos radiológicos preope-ratorios según grupo. Medidas trimestralmente, no hubo diferencias significativas entre proporciones de piezas con continuidad de cortical ósea y radiolucidez periapical postoperatoria según grupo, (p Fisher = 0.7780) y (p Fisher = 0.7909), respectivamente. Debi-do la escasa cantidad de trabajos que reportan el uso de EERR para esta técnica, se requiere de nuevos en-sayos clínicos con tamaños muestrales amplios, para compararlo con otros materiales y técnicas, y deter-minar si su tasa de éxito a largo plazo es mayor que a de los materiales y técnicas usadas actualmente (AU)

To perform apexification technique in one appointment, clinically and radiographically evaluating the formation of apical hard barrier, with follow-up at nine months, when using bioceramic material in young permanent teeth. Materials and methods: 30 permanent upper incisors with open apex and history of trauma were treated, in patients of both genders and 18-40 years of ages. The teeth (n=30) were divided into two groups (n=15). Experimental group: apexification treatment was performed with EndoSequence Root Repair Material (EERR), control group: treatment with apical impression. Frequency distributions and descriptive statistics were determined for each variable according to scale of measurement and distribution. 95% CI, Chi-square test with calculation of adjusted standardized residuals and Fisher's test were performed. The level of significance p=0.05 was set. The differences in preoperative and postoperative manifestations according to group were not statistically significant (Fisher's p = 0.9140) and (Fisher's p = 0.992), respectively. No differences were found between proportions of preoperative radiological findings according to group. Measured quarterly, there were no significant differences between proportions of teeth with bone cortical continuity and with postoperative periapical radiolucency according to group, (p Fisher = 0.7780) and (p Fisher = 0.7909), respectively. Due to the small number of works that report its use for this technique, is necessary to carry out new clinical trials with larger sample sizes, to compare it with other materials and techniques, and determine if its success rate in the long term is greater than that of currently used materials and techniques (AU)

Impact of different scan strategies and implant angulation on impression accuracy of full arch multiple implant: an in vitro study / Impacto de diferentes estratégias de escaneamento e angulação dos implantes na acurácia da moldagem de implantes múltiplos em arco completo: um estudo in vitro

Objective: to evaluate the impact of three different scan strategies and implant angulation on impression accuracy of an intraoral scanner for full-arch multiple implant scan. Material and Method: A maxillary edentulous model with six implant analogs served as a reference model. The four anterior analogs were positioned parallel to each other, the distal right and the distal left was placed with an angulation of 15o and 20o, respectively. Thirty impression were performed using an intraoral scanner (CEREC Primescan). The master cast was digitalized with an industrial reference scanner (ATOS Core 80). All scans were converted to standard tessellation language (STL), superimposed on the reference scan with a 3d inspection software (GOM Inspect Professional 2019) and then analyzed. Results: All linear distances presented equivalence [p<0.01] to those found on the reference scan for all scan strategies. All scan strategies presented a tendency of negative means for linear distances except for d4 in strategy C. All angular distances did not present equivalence [p=0.05] to those found on the reference scan. Significant 3D deviations [p<0.05] were found between strategy B (0.02 ± 0.01) and C (0.05 ± 0.04) for d1. In all others linear and angular distances no statistically significant difference was found between strategies A, B and C. Conclusions: There was no statistically significant difference between strategies A, B and C except for d1 in strategy B and C; Implant angulation did not affect the accuracy of the CEREC Primescan IOS (AU)

Objetivo: avaliar o impacto de três diferentes estratégias de escaneamento e angulação do implante na acurácia da moldagem de um scanner intraoral na moldagem de múltiplos implantes em arco completo. Material e Métodos: Um modelo edêntulo de maxila contendo seis análogos de implante serviu como modelo de referência. Os quatro análogos anteriores foram posicionados paralelos entre si, o distal direito e o distal esquerdo foram posicionados com angulação de 15o e 20o, respectivamente. Trinta moldagens foram realizadas usando um scanner intraoral (CEREC Primescan). O modelo mestre foi digitalizado com um scanner de referência industrial (ATOS Core 80). Todas as escaneamentos foram convertidas para a linguagem de mosaico padrão (STL), sobrepostas ao escaneamento de referência com um software de inspeção 3D (GOM Inspect Professional 2019) e, em seguida, analisadas. Resultados: Todas as distâncias lineares apresentaram equivalência [p <0,01] àquelas encontradas na escaneamento de referência para todas as estratégias. Todas as estratégias de escaneamento apresentaram tendência de médias negativas para distâncias lineares, exceto para d4 na estratégia C. Todas as distâncias angulares não apresentaram equivalência [p = 0,05] às encontradas no escaneamento de referência. Desvios 3D significativos [p <0,05] foram encontrados entre a estratégia B (0,02 ± 0,01) e C (0,05 ± 0,04) para d1. Em todas as outras distâncias lineares e angulares, nenhuma diferença estatisticamente significativa foi encontrada entre as estratégias A, B e C. Conclusões: Não houve diferença estatisticamente significante entre as estratégias A, B e C, exceto para d1 na estratégia B e C; A angulação do implante não afetou a precisão do CEREC Primescan. (AU)

Traditional versus simplified impression methods for complete dentures: critical appraisal of evidence / Método tradicional versus simplificado en impresiones para prótesis total removible: evaluación crítica de la evidencia Método tradicional versus simplificado

Abstract Introduction: Inspite of the great advances in dentistry, aging populations imply that there are still significant numbers of edentulous people worldwide. In most cases, implant-assisted prosthetic rehabilitation is the best solution. However, economic issues constrain access to this therapeutic approach, meaning that conventional removable prosthetics continue to be the most frequent treatment. In the removable denture making process, the so-called traditional method has been widely taught and used. It involves taking two impressions: a preliminary one followed by a definitive one (or functional). The simplified method constructs the prosthesis directly from the first impression obtained with a stock tray, without the need of a second impression. Purpose: To review the scientific evidence comparing both methods in terms of patient satisfaction, clinical quality, and masticatory performance and capacity. Results: No advantages have been found in favor of the traditional method regarding the four variables selected. Conclusions: According to the available information, the traditional method of taking impressions for complete removable dental prostheses does not provide significantly superior clinical results when compared to those obtained using the simplified method in terms of clinical quality, patient satisfaction, performance and masticatory capacity.

Resumen Introducción: Pese a los avances de la odontología, el fenómeno del envejecimiento de la población ha generado que la cantidad de personas desdentadas totales aún represente una cifra significativa. Los artificios protésicos implanto-asistidos constituyen, en la mayoría de los casos, la mejor alternativa rehabilitadora. Sin embargo, la variable económica surge como el principal impedimento para que los pacientes accedan a este recurso, y por este motivo, mantienen la prótesis total removible como una opción terapéutica. Para su confección, el método tradicional indica la necesidad de tomar dos impresiones: una preliminar y una definitiva o funcional. El método simplificado, confecciona la prótesis a partir de la primera impresión, obtenida con cubeta de stock. Objetivo: Revisar evidencia científica que compara ambos métodos en cuanto a las variables de: satisfacción del paciente, calidad clínica, rendimiento y capacidad masticatoria. Resultados: No se verifican ventajas a favor del método tradicional en relación a las variables estudiadas. Conclusiones: En concordancia con la información recabada, los resultados clínicos obtenidos mediante el método tradicional de toma de impresiones para prótesis totales no son significativamente superiores a los del método simplificado en relación a calidad clínica, satisfacción del paciente, rendimiento y capacidad masticatoria.

Precisión de los sistemas de impresión digital intraoral en odontología restauradora: Una revisión de la literatura / Accuracy of Intraoral Digital Impression Systems in Restorative Dentistry: A Review of the Literature

Abstract: La impresión intraoral permite al odontólogo obtener directamente los datos de las piezas dentales que se requiera rehabilitar, otorgándole mayor precisión y eliminando así de la fase clínica la toma de impresión y la fabricación del modelo, aspectos sensibles a errores. El objetivo de la presente revisión es identificar el sistema de impresión digital intraoral más preciso y además identificar los factores que afectan a la precisión de esta en odontología restauradora. Mediante una revisión bibliográfica con búsqueda en las bases de datos de PubMed y Embase se obtuvieron 153 artículos, luego de la evaluación cualitativa se incluyeron en la revisión 14 que cumplieron con los criterios de inclusión y exclusión. Se determinó que la experiencia del dentista, la convergencia en la preparación dental y la terminación cervical son determinantes al momento de la toma de impresión digital, sin embargo, el uso o no de polvo no es relevante. El sistema de impresión digital Lava C.O.S., iTero y True definition son los más precisos dependiendo siempre del tipo de rehabilitación a realizar.

Abstract: Digital impresión allows the dentist to directly obtain the data of the dental pieces that neet to be rehabilitated, giving it greater precisión and thus eliminating the impression and manufacturing of the dental model, error-sensitive aspects of the clinical phase. The aim of this review is to identify the most accurate intraoral digital impression system and identifiy the factors that affect the accuracy in the restorative dentistry. Through a bibliographic review with search in PubMed and Embase databases, 153 articles were obtained, after qualitative evaluation they were included in the revisión 14 that met the inclusion and exclusion criteria. It was determined that the experience of the dentist, the convergence in the dental preparation and the cervical termination are decisive at the accuracy of the digital impression, however, the use or not of dust is not relevant. The Lava C.O.S., iTero and True definition are the most accurate always depending on the type of rehabilitation to be performed.

Clinical performance of intraoral digital impression for fixed prosthodontics: a Meta-analysis / 华西口腔医学杂志

OBJECTIVES@#To analyze the clinical performance of the intraoral digital impression (IDI) in the fixed prosthodontics.@*METHODS@#Databases of Medline (Ovid), EMBASE, Cochrane Central Register of Controlled Trials, and CNKI were searched for randomized controlled trial (RCT) on the use of IDI in fixed prosthodontics until May 2020. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. A Meta-analysis was conducted when available.@*RESULTS@#Eleven RCTs involving 618 patients were included in this study. A total of 2 and 3 studies had low and high risks of bias, respectively, and other included studies had a medium risk of bias. Results illustrated that the IDI group could shorten the impression-taken time [SMD=-5.63, 95%CI (-11.25, -0.01), @*CONCLUSIONS@#Evidence indicated a good clinical performance of IDI for fixed prosthodontics. Notably, high-quality studies are expected to further support the conclusion.

Clinical application and research progress of digital complete denture / 华西口腔医学杂志

Digital technologies use high-precision three-dimensional scanning, intelligence-aided design software, and multi-axis numerical control milling or 3D printing, which can produce restorations with reliable precision and suitable function. However, the development of digital technologies in the field of complete denture restoration has been slow due to the complexity of prosthesis. This review article introduces the current research status and clinical applications of digital complete dentures in prosthodontic clinics and dental laboratories to provide beneficial references to prosthodontists and dental technicians.

Application of digital prosthesis in the repair of palatal fistula in rabbits / 中国组织工程研究

BACKGROUND: Digital impression technology has been widely used in the oral field. Compared with traditional impression technology, it is more convenient and accurate. OBJECTIVE: To explore the application of digital prosthesis for repairing palatal fistula in rabbits. METHODS: The rabbit models of palatal fistula were established by surgery. One month later, 10 rabbit models of palatal fistula were scanned by digital intraoral scanning system. The medical silicone rubber prosthesis for palatal fistula was manufactured by digital impression technology and digital design. After wearing the prosthesis, SUN LB, LAN YY, ZHOU HY, HUY. Application of digital prosthesis In me repair of palatal fistula In rabbits.  Zhongguo Zuzhi Gongcheng Yanjiu. 2020;24(14):2192-2196. DPI:10.3969/j.issn.2095-4344.2228 the accuracy, retention and sealing properties of the prosthesis were examined. The study was approved by the Laboratory Animal Ethical Committee of Hospital of Stomatology, Southwest Medical University. RESULTS AND CONCLUSION: After digital prosthesis repaired palatal fistula, the accuracy, retention and sealing properties of the prosthesis were good. To conclude, the digital prosthesis for palatal fistula repair by digital impression technology achieves accurate repair, and has certain clinical values.

Extended-pour and conventional alginates: effect of storage time on dimensional accuracy and maintenance of details

ABSTRACT Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student's t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured.

RESUMO Objetivo: O presente estudo teve como objetivo avaliar a estabilidade dimensional e manutenção de detalhes de alginatos convencionais e de alta estabilidade por até 5 dias de armazenamento. Métodos: Para esse estudo, foram selecionados dois tipos de alginatos: convencional (Hydrogum) (n = 10) e de alta estabilidade (Hydrogum 5) (n = 10), sendo produzidos com o auxílio de um bloco metálico cilíndrico e um molde metálico em forma de anel (especificações 18, 19 e 25, ANSI/ADA). Para o teste de estabilidade dimensional, dez imagens foram obtidas imediatamente e para cada tempo de armazenamento (15 min, 24, 48, 72, 96 e 120 horas), realizadas por câmera digital. As amostras foram mantidas hermeticamente fechadas em sacos plásticos (23°C). Para o teste de reprodução de detalhes, as amostras foram utilizadas para obter 140 (n = 70 por grupo) modelos de gesso, sendo observada a precisão angular de três sulcos (20 µm, 50 µm e 75 µm) para cada período. A precisão da reprodução de detalhes foi classificada usando uma classificação de pontuação predeterminada. As medições das mudanças dimensionais foram feitas no programa Corel DRAW X6. Os dados foram submetidos ao teste t de Student (α = 0,05). Resultados: Foi observada diferença estatística em relação à matriz após 24h para ambos os alginatos. Uma mudança dimensional linear negativa estatisticamente significativa (contração) foi verificada após 24 h de armazenamento (1,52% para alginato de alta estabilidade; 1,32% para alginato convencional). O alginato de alta estabilidade manteve os detalhes completos por até 72 horas, enquanto o alginato convencional, por 24 horas. Os alginatos reproduziram o sulco de 75 µm para todos os períodos. Conclusão: As impressões feitas com ambos os alginatos devem ser imediatamente vazadas para se ter resultados clínicos satisfatórios.

Evaluation of the influence of the impression technique, scanning direction and type of scanner on the accuracy of the final model / Avaliação da influência da técnica de impressão, direção de digitalização e tipo de scanner na precisão do modelo final

Objective: The purpose of this study is to evaluate the influence of the type of scanner and scanning direction on the accuracy of the final cast. Material and Methods: A partial master cast was used as a reference. A total of 128 scans were obtained and divided into two groups: the conventional method and the digital method. The digital group was divided into three groups: TRIOS 3, Omnicam and CS 3600. Each of these groups was subdivided according to the scanning direction, and each scan was overlaid on the digital reference cast to measure the trueness and precision of the procedures. Results: The overall precision values for the type of impression were 59.89 ± 13.08 µm for conventional and 13.42 ± 4.28 µm for digital; the values for trueness were 49.37 ± 19.13 µm for conventional and 53.53 ± 4.97 µm for digital; the scanning direction trueness values were 53.05 ± 4.36 µm for continuous and 54.03 ± 5.52 µm for segmented; and the precision values were 14.18 ± 4.67 µm for continuous and 12.67 ± 3.75 µm for segmented (p> 0.05). For the scanner type, the trueness values were 50.06 ± 2.65 µm for Trios 3, 57.45 ± 4.63 µm for Omnicam, and 52.57 ± 4.65 µm for Carestream; and those for precision were 11.7 ± 2.07 µm for Trios 3, 10.09 ± 2.24 µm for Omnicam, and 18.49 ± 2.42 µm for Carestream (p <0.05). Conclusions: The digital impression method is the most favorable method regarding precision; in terms of trueness, there are no differences between the types of impressions. (AU)

Objetivo: O objetivo deste estudo é avaliar a influência do tipo de técnica de moldagem, tipo de escâner intraoral e direção do escaneamento na precisão do modelo final. Material e Métodos: Um modelo parcial mestre foi usado como referência. Um total de 128 escaneamentos foi obtido e dividido em dois grupos: o método convencional (n = 32) e o método digital (n = 96). O grupo digital foi dividido em três grupos: TRIOS 3 (n = 32), Omnicam (n = 32) e CS 3600 (n = 32). Cada um desses grupos foi subdividido de acordo com a direção do escaneamento (n = 16), e cada escaneamento foi sobreposto ao modelo de referência digital para medir a veracidade e precisão dos procedimentos. Resultados: Os valores gerais de precisão para o tipo de impressão foram 59,89 ± 13,08 µm para convencional e 13,42 ± 4,28 µm para digital; os valores de veracidade foram 49,37 ± 19,13 µm para convencional e 53,53 ± 4,97 µm para digital; os valores de veracidade para a direção de digitalização foram 53,05 ± 4,36 µm para contínua e 54,03 ± 5,52 µm para segmentada; e os valores de precisão foram 14,18 ± 4,67 µm para contínua e 12,67 ± 3,75 µm para segmentada (p> 0,05). Para o tipo de scanner, os valores de veracidade foram 50,06 ± 2,65 µm para Trios 3, 57,45 ± 4,63 µm para Omnicam e 52,57 ± 4,65 µm para Carestream; e os de precisão foram 11,7 ± 2,07 µm para Trios 3, 10,09 ± 2,24 µm para Omnicam e 18,49 ± 2,42 µm para Carestream (p <0,05). Conclusões: O método de moldagem digital é o método mais favorável em relação à precisão; em termos de veracidade, não há diferenças entre os tipos de impressão (AU)