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Although intraoral scanners have gained in popularity, the traditional impression technique with a custom tray is still useful, particularly when making a definitive impression of multiple abutment teeth. A custom tray can be fabricated with a dental software program, avoiding the disadvantages of the manual laboratory procedures. However, additional module purchasing is necessary. This article presents a digital workflow for designing a custom tray by using an open-source software program.

OBJECTIVE: This study compares standard commercial bolus material (Superflab) to custom prepared silicone dental impression material (CDIM) and play dough material (PDM) with respect to dosimetric properties and applicability by using ion chamber measurement and calculated dose values. MATERIALS AND METHODS: The CDIM bolus was prepared by mixing dental impression silicone material with enough water to maintain a density of about 1.0 g/cm(3). The prepared bolus material is applied on an RW3 solid phantom by covering 10x10 cm(2) area with 0.5–1 cm thickness. Ion chamber measurements were performed separately with and without bolus material application. The setup was scanned in CT and the same procedure was repeated in the TPS using the scan data, in which the Pencil Beam Convolution dose calculation algorithm was used. To compare the effect of bolus material on tissue, the Superflab bolus and CDIM bolus were applied with 1 cm of thickness on postmastectomy scar and dose calculations on TPS were performed. RESULTS: After comparison of the dosimetric values for Superflab, CDIM and PDM, we obtained statistically meaningful results between superflab and CDIM. For PDM, the results obtained with TPS and ion chamber measurements indicated that, it is not suitable to use in radiotherapy application due to its material properties. For the simulated skin dose values obtained at five random points on the scar tissue, the comparison of Superflab and CDIM TPS calculation results were not statistically significant. CONCLUSION: The CDIM is easy to prepare and apply on irregular mastectomy scar tissue and it prevents formation of air gaps in the application surface. Especially for curved anatomical regions such as scar tissue, inclusion of the bolus material in treatment planning protocol will reduce dose uncertainty in application. It is safe to use CDIM as an alternative to Superflab in radiotherapy application, whereas PDM is not useful in clinical practice due to its material properties.

Backgrounds and objectives: Dental impressions present a risk to spread infections among dental practitioners and should be disinfected to prevent the spread of these microorganisms. Different disinfectant materials and techniques can be used to eliminate this threat. The purpose of this study was to evaluate the effect of some disinfectant materials with two different techniques on surface detail and dimensional stability of elastomeric impression materials. Materials and methods: Three dental impression materials were used in this study, Vinyl polysiloxane, Polyether and Vinyl polyether siloxane that were disinfected with sodium hypochlorite, Dettol and Cavex Impresafe by using two techniques, spraying and immersion methods for each. Results: The results of this study showed a significant difference of the dimensions between immediate and 48 hours after disinfection P

The technique described allowed an implant custom tray to be fabricated referencing the location of connected impression copings. The technique uses dental computer-aided design (CAD) software and 3D printing technology. The method controls the thickness of the impression material around the impression copings, improving the impression-making process.

Introduction The purpose of this study was to investigate differences in orthodontists' treatment plans based on digital models compared with plaster models. Additionally, we assessed whether digital or plaster models influence the reliability of orthodontists' treatment plans, as well as the amount of time required to arrive at the plan. Methods Sixteen orthodontists planned treatment for 20 patients at 2 time points using either the same or different model formats (digital or plaster). The treatment plan decisions and time spent making the plans were recorded. The permutation test and a random effects model were used to analyze the data. Results The treatment plans arrived at with digital and plaster models were similar. With respect to extractions, the mean difference between digital and plaster formats was 11.9% (95% CI, 7.5%-16.3%). For surgery, the mean difference was 9.4% (95% CI, 5.0%-13.8%). There was no significant difference in the agreement rate between those who viewed models in different formats compared with those who viewed models twice in the same format (P >0.05). The time spent to plan treatment with plaster models was not significantly different from the time spent with digital models (P = 0.87). Conclusions Based on this study, digital models can be substituted for plaster models with no significant differences in the final plans, the reliability of the plans, and the time required to create the plan.

Aim and Objective. Impression materials and stone casts are the main sources of cross-contamination and transmission of dental infections between dental offices and laboratories. Both Surfosept (alcohol-based) and Deconex® (quaternary ammonium compound) are biocompatible solutions that have superior antimicrobial properties against bacteria, fungi, and viral envelope. Considering the influence of disinfection substances on the dimensions of impression materials, this study aimed to compare the effect of Surfosept and Deconex® 53 on the accuracy and dimensional stability of the Panasil® dental addition silicone material. Materials and Methods. This in vitro study was performed on 30 dental casts. The samples were divided into one control group and two experimental groups to be disinfected with Surfosept (1%) and Deconex® 53 (2%) using a sequential sampling method (10 per group). The impressions in the experimental groups (i.e., Surfosept and Deconex® 53) were rinsed and dried; then, the disinfectant was sprayed on the impressions and remained for 30 seconds before pouring with stone. In the control group, the impressions were only rinsed and dried and were poured in 10 minutes. Cast dimensions were measured by a profile projector device, and the mean values obtained from the experimental groups were compared with those of the control group. Results. There were no significant differences among the groups regarding the height of the resulting dies without undercut ( P = 0.62 ). Moreover, there was no significant difference among the groups regarding the distance between the two dies ( P = 0.77 ). However, the diameter of the dies with undercut and without undercut was different significantly among the control and experimental groups ( P < 0.005 ). Conclusion. In general, no significant difference was encountered between dimensional stability and accuracy of the dental impressions using Surfosept and Deconex® 53 in this study.

Source of funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectorsType of study/design Randomised controlled trial (RCT) with parallel design.Subjects This RCT was conducted at the Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Centre of Dental Medicine, University of Zurich, Zurich, Switzerland. Ten patients, six women and four men, with a mean age of 62 years and an age range of 49-77 years, requiring posterior tooth-supported 3-unit fixed partial dentures (FPDs) were included in this RCT. The abutment teeth were six molars and six premolars in the maxilla and five molars and three premolars in the mandible. The patients fulfilled the following inclusion criteria: they all were >18 years, with a full mouth plaque score

The advent of new technologies in the field of medicine and dentistry is giving improvements that lead the clinicians to have materials and procedures able to improve patients’ quality of life. In dentistry, the last digital techniques offer a fully digital computerized workflow that does not include the standard multiple traditional phases. The purpose of this study is to evaluate all clinical trials and clinical randomized trials related to the digital or dental impression technique in prosthetic dentistry trying to give the readers global information about advantages and disadvantages of each procedure. Data collection was conducted in the main scientific search engines, including articles from the last 10 years, in order to obtain results that do not concern obsolete impression techniques. Elsevier, Pubmed and Embase have been screened as sources for performing the research. The results data demonstrated how the working time appears to be improved with digital workflow, but without a significant result (P = 0.72596). The papers have been selected following the Population Intervention Comparison Outcome (PICO) question, which is related to the progress on dental impression materials and technique. The comparison between dentists or practitioners with respect to classic impression procedures, and students open to new device and digital techniques seem to be the key factor on the final impression technique choice. Surely, digital techniques will end up supplanting the analogical ones altogether, improving the quality of oral rehabilitations, the economics of dental practice and also the perception by our patients.

To reduce inter-implant metal artifacts in cone-beam CT (CBCT) imaging by adjusting angular position of the subject relative to the source–detector plane. Two dental implants were placed in a block made of homogeneous dental impression material. Using a custom-made apparatus, the specimen was scanned with a CBCT machine at seven different angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) along three different spatial axes, yielding 21 experimental groups. Thirteen volumes of interest (VOI) including inter- and peri-implant areas were selected from each axial reconstruction perpendicular to the implants. Gray values (GVs) of each pixel within these VOIs were measured. Mean differences in GV (ΔGV) between the VOIs and control area were calculated and expressed as a percentage. These ΔGVs from different spatial angle were compared and analyzed by Welch’s analysis of variance (ANOVA) and linear regression using SPSS 25.0 software. As alpha angle increased, the ΔGV of the inter-implant area increased from − 62.02% to near-zero while the standard deviation decreased. Welch’s ANOVA and linear regression analysis revealed ΔGV increased significantly with alpha angle (p

Purpose Capturing implant position in impression-making procedures commonly involves transfer devices, such as implant impression copings and laboratory analogs. These components are intricately machined, including the lumen, and often include additional features for prevention of screw dislodgment. The Centers for Disease Control and Prevention recommends all surfaces in contact with human bodily fluid be disinfected with hospital-grade disinfectant. The ability of these components to harbor biologic contaminant material has not yet been determined, especially with regard to internal configuration, combined with the knowledge that many clinicians and laboratories use a spray disinfectant, which may limit disinfectant contact. The aim of this study was to determine the site and extent of contamination occurring on implant components following clinical impressions and laboratory procedures. Materials and methods The study design included forensic staining and subsequent analysis of 60 used impression copings, 10 used laboratory analogs, and 10 new components as controls. Results Staining was found on 100% of impression copings used in vivo, indicating that biologic material had reached multiple sites on both internal and external surfaces of the components. Staining was also found on the internal aspect of used implant analogs, indicating transfer of biologic material from the impression coping and screw. None of the new control components presented staining at any site. Staining highlighted difficult areas to debride, particularly components with difficult or impossible access for cleaning and disinfection. Conclusion Phloxine B staining indicated the ability of biologic material to reach all areas of the implant components. Having demonstrated the difficulty, sometimes impossibility, of accessing areas of these implant components, there is a need to develop protocols to reduce risk of potential transmission of infective material via implant components. Further study is warranted to determine the potential for transmission of infective material due to inadequate disinfection processes of implant componentry.

Inattention while taking dental impressions of the upper jaw of patients with a palatal defect can lead to dental impression material being left behind. Two patients with a cheilognathopalatoschisis and a full arch prosthesis in the upper jaw were referred with complaints characteristic of chronic sinusitis and recurrent epistaxis, lasting several years. A facial cone beam computer tomogram revealed dental impression material left behind in the palatal defect and the nasal cavity. In the case of both patients, the foreign bodies were removed under general anaesthesia. One of the patients twice brought up a residual fragment of dental impression material left in the palatal defect after surgery.Onopmerkzaamheid bij het nemen van gebitsafdrukken van de bovenkaak bij patiënten met een palatumdefect kan leiden tot het achterblijven van tandheelkundig afdrukmateriaal. Twee patiënten bekend met een cheilognathopalatoschisis en een volledige gebitsprothese in de bovenkaak werden verwezen in verband met sinds jaren bestaande klachten passend bij chronische sinusitis en recidiverende neusbloedingen. Na het vervaardigen van een conebeamcomputertomogram van het aangezicht bleek er sprake te zijn van achtergebleven tandheelkundig afdrukmateriaal in het palatumdefect en in het cavum nasi. De corpora aliena werden bij beide patiënten onder algehele anesthesie verwijderd. Een van de patiënten heeft na de operatie tot tweemaal toe een achtergebleven fragment van het tandheelkundig afdrukmateriaal opgegeven dat afkomstig was uit het palatumdefect.

Introduction: No medical intervention is required for emergency department applications resulting from foreign body ingestion. Patients who need intervention are generally with complications such as obstruction, perforation or fistula. Alginate is a non-toxic and non-irritant substance that is elastic in the form of a paste preserving its elasticity under heat, which is used as a printing material for measuring the teeth in dental prosthesis applications . A case of ileus developing as a result of ingestion of alginate impression has been presented. Case report: A 74-year-old male patient presented to our emergency department due to abdominal pain nausea and vomiting . He described periumbilical pain and stated that he felt mild swelling. He had vomit one time and the content of vomit was what he had eaten. On physical examination, his abdomen was slightly distended, bowel sounds had increased slightly on auscultation and there was mild periumbilical tenderness with palpation, with no defence or rebound. On the abdominal CT evaluation, a homogeneous, lobulated, hyperintense foreign body image was detected in the distal ileus and distension in the small bowel loops proximal to the foreign body was interpreted. After general surgery consultation, distal ileal resection was performed and pink, homogenous, slightly soft charactered object was extrected. Later this object was understood to be alginate impression. Conclusion: Elderly patients in particular, ileus may occur due to foreign body associated with dental interventions, and in such cases, patients may need surgical intervention.

This article describes a step-by-step digital protocol for the design and fabrication, through additive manufacturing, of a splinted framework and a custom tray for the impression of a complete-arch prosthesis supported by multiple implants. The protocol presented uses open source software to control the thicknesses of the custom tray, splinting material, and impression material during the procedure, reducing laboratory and chairside time and costs.

This article describes the cause of a sinus tract developed four years after implant-supported prosthodontic treatment. The sinus tract and pain appeared to be associated with an accidentally embedded piece of condensation silicone impression material. The residual material was removed by a simple surgical incision. Clinicians should be aware of the odds of this event and take it into consideration whenever there is a similar postoperative problem.

Digitalization of the design and manufacture of removable complete dentures has numerous advantages. The workflow as presented integrates current open digital technologies into a functional protocol, enabling complete dentures to be designed and fabricated without system-specific trays or instruments. This is done by using a conventional technique to acquire anatomic information.

This study describes a method for measuring the accuracy of the virtual impression. In vitro measurements according to a metrological approach were based on (1) use of an opto-mechanical coordinate measuring machine to acquire 3D points from a master model, (2) the mathematical reconstruction of regular geometric features (planes, cylinders, points) from 3D points or an STL file, and (3) consistent definition and evaluation of position and distance errors describing scanning inaccuracies. Two expert and two inexpert operators each made five impressions. The 3D position error, with its relevant X, Y, and Z components, the mean 3D position error of each scanbody, and the intra-scanbody distance error were measured using the analysis of variance and the Sheffe’s test for multiple comparison. Statistically significant differences in the accuracy of the impression were observed among the operators for each scanbody, despite the good reliability (Cronbach’s $$\alpha $$ = 0.897). The mean 3D position error of the digital impression was between 0.041 ± 0.023 mm and 0.082 ± 0.030 mm. Within the limitations of this in vitro study, which was performed using a single commercial system for preparing digital impressions and one test configuration, the data showed that the digital impressions had a level of accuracy comparable to that reported in other studies, and which was acceptable for clinical and technological applications. The distance between the individual positions (#36 to #46) of the scanbody influenced the magnitude of the error. The position error generated by the intraoral scanner was dependent on the length of the arch scanned. Operator skill and experience may influence the accuracy of the impression.

PURPOSE: To compare operating time and patient perception of conventional impression (CI) taking and intraoral scanning (IOS) for manufacture of a tooth-supported crown.MATERIALS AND METHODS: A total of 19 patients needing indirect full-coverage restorations fitting the requirements for a split-mouth design were recruited. Each patient received two lithium disilicate crowns, one manufactured from CI taking and one from IOS. Both teeth were prepared following the manufacturers' recommendations. For both impression techniques, two retraction cords soaked in 15% ferric sulphate were used for tissue management. CIs were taken in a full-arch metallic tray using one-step, two-viscosity technique with polyvinyl siloxane silicone. The operating time for each step of the two impression methods was registered. Patient perception associated with each method was scored using a 100-mm visual analog scale (VAS), with 100 indicating maximum discomfort.RESULTS: Median total operating time for CI taking was 15:47 minutes (interquartile range [IQR] 15:18 to 17:30), and for IOS was 5:05 minutes (IQR 4:35 to 5:23). The median VAS score for patient perception was 73 (IQR 16 to 89) for CI taking and 6 (IQR 2 to 9) for IOS. The differences between the two groups were statistically significant (P < .05) for both parameters.CONCLUSION: IOS was less time consuming than CI taking, and patient perception was in favor of IOS.

Discoveries of foreign bodies lodged in the nose, palate and maxillary sinuses have been well documented. A rare, iatrogenic cause is displacement of dental impression material which, if left undetected at these sites, may lead to acute respiratory obstruction or chronic problems, such as nasal discharge and chronic sinusitis. This article reports the case of acute complications following displacement of dental impression material into a palatal cleft, discusses immediate surgical management, and considers restorative techniques that should be adopted to prevent such complications in patients with cleft palates. CPD/Clinical Relevance: Impression-taking in patients with cleft palate carries significant risks and appropriate referral to a multidisciplinary team is appropiate in order to avoid potentially life-threatening complications.

The use of digital intraoral scanners is increasing; however, evidence of its precision in making crown impressions clinically remains scarce. Patients should also feel more comfortable with digital impressions, but only a few studies evaluating this subject have been performed.The purpose of this clinical study was to evaluate the marginal fit of monolithic zirconia crowns and patients' preferences for digital impressions versus polyvinyl siloxane (PVS) impressions.Sixteen participants with indications for single molar crowns were included. After crown preparation, digital impressions by intraoral scanner and PVS impressions were made. The participants were asked to complete a 6-item questionnaire with a visual analog scale related to perceptions of each of the following topics: time involved, taste/smell, occlusal registration, size of impression tray/scanner, gag reflex, and overall preference. Computer-aided design and computer-aided manufacturing monolithic zirconia crowns were fabricated from both impressions. The crowns were evaluated intraorally, and a blinded examiner measured the marginal discrepancy of silicone replicas under a stereomicroscope. Intraexaminer reliability was evaluated by calculating the intraclass correlation coefficient. Data for patients' preferences and marginal discrepancies were analyzed using the paired t test (α=.05).Visual analog scale scores for digital impressions were statistically significantly higher than those for PVS impressions in every topic (P.05), except for occlusal registration. The results showed excellent reliability of the examiner with an intraclass correlation coefficient of .996. No significant difference was found in marginal discrepancies between the PVS group and the digital group on all sides (P.05).No differences were found in the clinical marginal fit of zirconia crowns fabricated from either digital impressions compared with PVS impressions. Furthermore, patients' satisfaction with digital impressions was significantly higher than with conventional impressions.

Foreign bodies found in the maxillary sinus include tooth roots, burs, dental impression material, root-filling materials, dental implants, and needles. The purpose of this paper was to present an unusual case of a large foreign body of endodontic origin (root-filling material) removed from the maxillary sinus. A 45-year-old generally healthy male patient reported to the Department of Conservative Dentistry with Endodontics of the Medical University of Silesia, because of orbital and buccal pain on the right side of his face and headaches in the preceding 6 months. Those symptoms were associated with the end of endodontic treatment of teeth 14 and 16. Periapical X-rays, including of teeth 14 and 16, showed the presence of root canal filling with extrusion of endodontic obturation material beyond the apices of tooth 14. In the case of tooth 16, a completely filled palatal canal and incompletely filled buccal canals were found. There was also an irregular dimness at the upper edge of the X-ray image. Panoramic radiography and computed tomography demonstrated a foreign body in the right sinus. Sinus exploration was performed via a surgical procedure conducted using topical anesthesia. The root apices of tooth 14 were resected, and foreign substance was removed. The practitioner did not correctly recognize a complication that occurred during endodontic treatment, which resulted in extrusion of endodontic material beyond the root apices of tooth 14. This case emphasizes the potential impact that an involved maxillary sinus may have on endodontic therapy. Detailed diagnostic identification based on the medical interview, physical and histopathological examinations, and diagnostic imaging allowed rapid surgical intervention and prevented local and general complications. It is important to realize that the range of the periapical X-ray projection is not always sufficient. Keywords: extrusion of endodontic obturation materials, foreign body, maxillary sinus

Background Colour degradation is a major problem in maxillofacial silicone elastomers. Recent studies have focused on colour stability and the mechanical properties of the silicone elastomers. A colour match is also essential for the acceptance of the prosthesis by the patient. The aim of this study is to assess the colour degradation of the silicone elastomer after being moulded in different colours of dental stones at two different vulcanization temperatures. Methods Five different colours of dental stones were used to fabricate a total of 120 silicone blocks using a Cosmesil M511 maxillofacial silicone elastomer. Vulcanization was completed at two different temperatures (25 and 100° Celsius). Colour measurements were obtained with a Conica Minolta spectrophotometer. The CIEDE2000 formula was used to calculate the colour differences (∆E00). Two-way ANOVA, one-way ANOVA with Bonferroni corrected post-hoc p values and independent samples t-test were used for the statistical analyses. Results High temperature vulcanization causes lightening of the maxillofacial silicone elastomers without regard to the dental stone colour (p = 0.001). Specimens moulded in green stone lightened least at room temperature (p = 0.999). Compared to the control group, at high temperature, all specimens moulded in coloured dental stones darkened significantly (p

ESPE, the market leader, is a medium-sized German manufacturer of precision dental impression materials competing in a shrinking market. To grow the business, ESPE invests substantial resources in innovative impression materials and associated distribution mechanisms. Squeezed by the shrinking market, the competition is increasingly using the proprietary channels (dispensing mechanisms) and brand equity (trademark) of ESPE to maintain their market share. There is a potential infringement. Explores how ESPE is organized to execute on the options imbedded in its IP rights.To provide students with an understanding of how to use brands and trademarks in conjunction with trade secrets, patents, and other forms of IP in mature markets to build and maintain innovation-based competitive advantage.

Purpose This study aims to determine the number, symmetry, shape and individual characteristic of palatal rugae. Methods In our study, we performed on subjects ages 16 to 57 (23.01 ± 7.12), ranging from a total of 230 (108 female and 122 male). Alginant impression material from each took dimensions of the upper jaw. Then casts were obtained by pouring hard casts. The shapes, lengths, and directions of rugae measured on these casts. The palatine photos were taken by using a mobile phone-Samsung brand with 12 MP camera and an orthodontic mirror. The casts and photographs were selected at random belonging to 100 subjects. Selected at random 10 photographs were matched among 100 casts. The ratios of correct matches were determined. Results In our study, the total number of palatal rugae was found as 9.49 ± 1.87 in females and 9.42 ± 1.92 in males. The most detected rugae pattern was wavy on both females and males. The most rarely seen rugae pattern was converged in the males and circular in the females. Regarding lengths of rugae, the most detected rugae pattern was the primary one. Regarding the direction of rugae pattern, positive-sided one was the most dominant in both genders. We determined the ratio of matching the casts belonging to Palatine with the photos as 63.5%. The number of rugae aged under 18 and above 41 was found to be statistically significant (P = 0.003), but the number of curved and positive-sided rugae in older ages was not found to be statistically significant. Conclusions Compared with data from earlier studies, the shapes, length, and direction of palatal rugae were seen specific in every individual, and it was seen to have discriminating characteristics among different populations. The possible differences in individual specific palatal rugae require further studies involving larger samples.

AIM The purpose of the present study was to assess the accuracy of intra-oral scans and conventional impression measured at various points on a single tooth preparation. Methods Ten conventional silicone impressions, and ten intra oral-scans using eight different digital intra oral digital scanners were taken of a prepared master tooth. The conventional impressions were directly digitised using a laboratory scanner. Each scan/impression was superimposed on a high-accuracy digital model of the prepared master tooth. For each superimposition, the deviation from the prepared master tooth was measured at six points on four two-dimensional cross-sections. Data was analysed using two-way analysis of variance (ANOVA). Results Most intra oral scanners had lower accuracy at the preparation margin compared to smooth surfaces. When only conventional impression and the latest intra oral scanners of various manufacturers are considered, the mean discrepancy at the preparation margin was 50μm (SD 16) for conventional impression, 15μm (SD 4) for Trios 3, 26μm (SD 4) for LAVA TDS, 29μm (SD 7) for CEREC Omnicam, 30μm (SD 6) for CS 3600 and 64μm (SD 7) for GC Aadva. The increased accuracy of Trios 3 was statistically significant (pConclusions At the preparation margin, Trios 3 performed significantly better than conventional impression and the other intra oral scanners. LAVA TDS, CEREC Omnicam and CS3600 showed similar accuracy at the margin, yet better than conventional impression and GC Aadva.

STATEMENT OF PROBLEM. The definitive impression for a single-unit crown involves many material and technique factors that may affect the success of the crown. PURPOSE. The purpose of this prospective cohort study was to determine whether impression technique (tray selection), impression material, or tissue displacement technique are associated with the clinical acceptability of the crown (CAC). MATERIAL AND METHODS. Dentists in the National Dental Practice-Based Research Network (N=205) documented details of the preparation, impression, and delivery of 3730 consecutive single-unit crowns. Mixed-model logistic regression analyses were used to evaluate associations between impression techniques and materials and the CAC and to assess associations between the presence of a subgingival margin with the displacement technique and the outcome variables CAC and number of impressions required. RESULTS. Of the 3730 crowns, 3589 (96.2%) were deemed clinically acceptable. A significant difference in the CAC was found with different impression techniques (P

Made available in DSpace on 2019-10-03T17:32:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2019. Added 1 bitstream(s) on 2019-10-04T16:21:03Z : No. of bitstreams: 1 S1807-25772019000100425.pdf: 1513724 bytes, checksum: 8d45c56b7240addf579f480ae922097e (MD5) ResumoIntrodução Realizar moldagens precisas e dimensionalmente estáveis que dupliquem a condição oral é um passo essencial para a confecção de restaurações indiretas de qualidade, garantindo seu sucesso e longevidade. Diversos estudos tem demonstrado os prós e contras de diferentes técnicas de moldagem, mas nenhum consenso da melhor técnica ainda foi descrito.Objetivo Este estudo avaliou a exatidão de modelos de gesso confeccionados por diferentes técnicas de moldagem, moldeiras e materiais.Material e método 10 pacientes foram selecionados e 20 moldes dos dentes #13 até #16 foram realizados utilizando técnicas simultânea (SS) e de dois passos, realizados com moldeiras parciais metálicas e individuais de resina acrílica, silicones de adição e condensação. Gesso tipo IV foi usados para os vazamentos. Três fotografias de cada paciente (baseline), assim como dos seus respectivos modelos de gesso foram realizadas e sua área foi então mensurada, na porção vestibular. Comparações de valores de área entre os grupos experimentais e o baseline foram performadas. Os dados mostraram aderência a curva normal, sendo submetidos ao teste 3-way ANOVA/Bonferroni (α=.05).Resultado As técnicas produziram diferenças significativas (P=0.02).Técnica simultânea foi mais precisa que a BUR (P=0.0003; 95=1,22 a 5.98), mas ambas resultaram em modelos similares àqueles feitos por meio das técnicas de PVC, MOV e sem NR, que foram similares entre si (P>0.05).Conclusão Técnica simultânea demonstrou valores absolutos similares àqueles demonstrados pelo baseline. AbstractIntroduction Making accurate and dimensionally stable impressions to duplicate oral conditions and tooth morphology is an essential step of prosthetic dentistry for fabricating well-fitted indirect restorations and, consequently, ensure the longevity and success of the treatment. Several authors describe pros and cons of different impression techniques, although there is no unanimity among them about the best one.Objective This study evaluated casts’ accuracy made by different impression techniques, trays and materials.Material and method 10 patients were selected and 20 impressions from teeth #13 to #16 were performed using single-step (SS) and two-step techniques, made with metal stock and customized acrylic resin partial trays, vinyl polysiloxane and condensation silicone rubbers. Type IV gypsum was used to pour the casts. Three photographs of each patient (baseline), as their respective gypsum casts, were taken, measured in their interested buccal surface area. Comparisons of area values among experimental groups and baseline were performed. Data showed adherence to normal curve, being submitted to 3-way ANOVA/Bonferroni test (α=.05).Result Technique produced significant differences (P=0.02). SS technique was more accurate than BUR one (P=0.003; 95=1.22 to 5.98), but both resulted in similar casts to PVC, MOV and NR techniques, which were similar to each other (P>0.05).Conclusion SS technique showed the closest absolute values to baseline. Universidade Estadual Paulista Faculdade de Odontologia de Araraquara Departamento de Materiais Odontológicos e Prótese Universidade de Araraquara McGill University Faculty of Dentistry Division of Oral Health and Society Universidade Estadual Paulista Faculdade de Odontologia de Araraquara Departamento de Materiais Odontológicos e Prótese

A fully digital workflow for designing and manufacturing a splinted framework and a custom tray for the impression of multiple implants placed with guided surgery is described. This digital workflow protocol does not require extra visits after surgery to prepare for the definitive impression because of the use of preoperative digital implant planning data. As a result, it helps reduce laboratory procedures, chairside time, and treatment cost.

Purpose To investigate whether hemostatic agents have any detrimental effects on polyether impressions and plaster casts after a clinically viable cleaning protocol. Materials and methods A total of 60 human molar teeth were manually standardized, prepared, and subdivided into five groups (G): G0 (control/no contamination); G1 (ViscoStat Clear); G2 (ViscoStat); G3 (Astringedent); and G4 (Astringedent X). Each tooth was contaminated with a hemostatic agent for 3 minutes and cleaned with a 30-second air/water spray. Before and after contamination, an impression was taken and a plaster cast was poured. The impressions and plaster casts of all teeth were scanned using a light scanner. Data were matched using a three-dimensional analysis software that displayed color-coded maps. Means of the maximum positive/negative values and of the mean deviations in each group were calculated and compared. All color-coded maps were interpreted descriptively using the program's color scale, and all impressions and plaster casts were microscopically evaluated. Results Values of mean deviations throughout all matched scans showed maximum values ranging from -30.1 to +17.5 μm. None of the groups showed significantly different deviation values or patterns when compared to each other. Impressions showed a thin, discontinuous coating for G2, G3, and G4; no changes were found for plaster casts. Conclusion Presented deviations showed the same values and distribution patterns within all groups. A cleaning protocol of 30 seconds of air/water spray is sufficient to remove hemostatic agents, preventing effects to polyether impressions and plaster casts. However, ferric sulfate-containing hemostatic agents left discontinuous coatings on impression surfaces.

PURPOSE To report the success of a repair service set for the retrieval of fractured screws and to compare three clinical assessments to an in vitro assessment to verify the completeness of removal of the fractured screws. MATERIALS AND METHODS Twelve clinicians were asked to remove fractured implant abutment screws from prepared specimens by means of a repair service set. The completeness of the removal of any abutment screw material was measured by the fit of an impression post, a dental surgery microscope, and the use of an elastomeric impression material. RESULTS After the participants attempted to remove the fractured screw with the repair service set, 100%, 83.3%, 66.7%, and 75% of the fractured screws were considered successful in the impression post, dental surgery microscope, silicone replica, and stereomicroscope assessments, respectively. CONCLUSION The retrieval of fractured screws succeeded in 75% of the cases. The silicone replica technique and the dental surgery microscope had similar diagnostic values to the stereoscopic microscope assessment.

Purpose Intraoral scanners (IOSs), which create digital “impressions” of dental arches, have become popular for prosthetic and orthodontic applications. Adoption in oral and maxillofacial surgery (OMS) practices has been slower, likely because of high implementation costs and low-volume use. The purpose of this study was to evaluate costs for introduction of an IOS into an OMS practice. The authors hypothesized that digital impressions would be more efficient in time and cost compared with conventional impressions and that implementation costs would be offset within 1 year. Materials and Methods This was a prospective study that included patients who had digital impressions during the first year after introduction of an IOS to the practice. Conventional alginate impressions obtained at the same visit were included for comparison. Variables included time for each step in each impression process, IOS experience of the operator obtaining the impression, and associated costs. Per-arch costs for each technique were calculated using time-driven activity-based costing methodology. Results Sixty-three digital impressions and 31 conventional impressions were included. Mean total times for digital and conventional impressions were 14.1 ± 1.3 and 19.4 ± 4.0 minutes per arch, respectively. On a per-patient basis (2 arches for digital impressions and 4 arches for conventional impressions because of the inability to create duplicate stone models from each alginate impression), total impression times were 24.8 ± 2.7 minutes for digital and 67.2 ± 14.8 minutes for conventional impressions. Total calculated costs for digital and conventional impressions were $21.42 and $29.40 per arch and $37.66 and $102.10 per patient, respectively. In a practice with 2 patients for impressions per working day (500 per year), it would take 1.04 years to offset the purchase of the IOS; with 5 sets of impressions per day (1,250 per year), it would take 5 months. Conclusion Digital impressions are more efficient and cost effective than standard impressions, and implementation costs can be offset within the first year.

Esthetic features of life are of great general importance to people. Teeth are of significance in this regard as they somehow are the key elements of individuals’ character by reflecting the amount of attention one may receive among the public by means of communication. In this sense a subfield of medicine, called dentistry, has been specialized for identifying the diagnosis, prevention, and treatment of the diseases, disorders, and the conditions of oral cavity, as well as related structures and tissues. Meanwhile, there has been a significant progress in the past decades associated with the design and manufacture of dental materials. Correspondingly, so many compounds and formulations have been produced to gain advanced materials for dental applications. Dental impression materials (IMs) have been utilized as negative molds to fabricate appropriate casts, by which different trays have been utilized as supports for the IMs to fit over the dental arches. Although various natural and synthetic materials have been utilized so far as dental IMs, they are frequently classified based on their properties into two groups, that is, elastic and inelastic families. In addition to the stiffness, other features, such as stability, accuracy, and wettability, play essential roles in IM performance. In this overview, materials utilized for their impression function are dealt with, and their properties are discussed to pave a way for those seeking appropriate materials for dental prosthesis purposes.

Oral mucocele is a benign cystic exophytic lesion affecting the minor salivary gland and is especially present in pediatric patients (3% under 14 years). It is characterized by an extravasation or retention of fluid or mucus in the submucosal tissue of the minor salivary glands. Several surgical techniques have been proposed over the years, including the excision of the mucocele by using the injection of a hydrocolloid impression material in the light of the cyst to prevent the collapse of the cystic wall and solidify the lesion, resulting in a better cleavage plan. The combined clinical approach between the combination of Shira’s technique and the surgical excision of the cystic lesion results in a conservative surgical removal of the lesion. Here, we reported the removal of a labial mucocele in a 14-year-old male patient, using the injection of a hydrocolloid impression material. At a 12 months follow up, the patient showed complete healing of the surgical site, showing a pinkish lip lining mucosa without scarring or recurrence of the primary lesion. The combined therapeutic approach between Shira’s technique and surgical excision allows a safe and predictable excision of the labial mucocele, minimizing the risk of recurrence.

The impression technique described combines elastomeric impression materials and irreversible hydrocolloid to make an accurate preliminary impression of extremely mobile and misaligned teeth. Upon setting, the materials are removed from the mouth in 3 different directions and reassembled extraorally. This technique provides an alternative, easy, accurate, and safe way to make a preliminary impression of mobile, periodontally involved teeth.

INTRODUCTION: The aim of this crossover study was to assess perceptions and preferences for impression techniques in young orthodontic patients receiving alginate and 2 different digital impressions.METHODS: Thirty-eight subjects aged 10 to 17 years requiring impressions for orthodontic treatment were randomly allocated to 3 groups that differed in the order that an alginate impressions and 2 different intraoral scanning procedures were administered. After each procedure, the patients were asked to score their perceptions on a 5-point Likert scale for gag reflex, queasiness, difficulty to breathe, uncomfortable feeling, perception of the scanning time, state of anxiety, and use of a powder, and to select the preferred impression system. Chairside time and maximal mouth opening were also registered.RESULTS: More queasiness (P = 0.00) and discomfort (P = 0.02) during alginate impression taking of the maxilla were perceived compared with the scans with the CEREC Omnicam (Sirona Dental Systems, Bensheim, Germany). There were no significant differences in perceptions between the alginate impressions and the Lava C.O.S. (3M ESPE, St Paul, Minn) and between the 2 scanners. Chairside times for the alginate impressions (9.7 ± 1.8 minutes) and the CEREC Omnicam (10.7 ± 1.8 minutes) were significantly lower (P CONCLUSIONS: Young orthodontic patients preferred the digital impression techniques over the alginate method, although alginate impressions required the shortest chairside time.

Purpose To compare the dimensional accuracy of dies generated from digital intraoral scans with dies generated from conventional polyvinyl siloxane (PVS) impression material. Materials and Methods A machined metal die was impressed 10 times using PVS, and scanned 10 times using the iTero Cadent system and 10 times using the LAVA C.O.S. system. Dies generated from each system were imaged in a standardized holder using a microscope and measured with analytical software at three sites and compared with the dimensions of the master die. Results The dimensional differences between the master die and both the PVS and iTero groups were approximately 60 μm in all three dimensions but the Lava C.O.S. die dimensions measured close to 100 μm at two of the three sites. Conclusion PVS/Die and iTero groups offered superior reproduction of the master die in terms of dimensional accuracy, but these differences are likely of little clinical significance.

The selection of patch test haptens contained in oral rehabilitation materials is not an easy task, therefore baseline series and additional dental series are used for screening and to increase the chance for the detection of patient's contact sensitizations. Moreover, the clinical relevance of positive patch tests must be evaluated. We conducted a biomedical literature search, covering a period of thirty years, using the keywords: contact, allergy, dental, allergens, patch, patients, screening, in order to evaluate many studies including large numbers of patients, tested to various hapten series, in different departments, for the detection of the most common contact allergens involved in dental contact hypersensitivity. We propose a short patch test series of oral rehabilitation materials for patients including six metal haptens present in dental alloys for inlays, crowns, bridges and dentures, one monofunctional methacrylate and one epoxy prepolymer present in dental composite resins, dentin bonding agents and prosthetic materials, one epoxy resin type present in root canal sealants, three odorant constituents contained in provisional restorative and root canal filling materials, periodontal dressings and dental impression materials. Contact allergy to dental haptens is a constant studied subject, but the cost of patch testing with screening and additional or extensive series is relevant, therefore the proposal of a shorter dental material series for patients is aimed to promote sustainability of oral rehabilitation and contact hypersensitivity care and to reduce costs in some real-world settings.

Statement of problem The mechanical-chemical technique and the use of a laser are methods for displacing the gingiva to make an accurate impression of the preparation for a complete crown. The tissue needs to be displaced and the hemorrhage controlled to capture the prepared finishing line in the impression. The degree of undesirable gingival recession after these displacement techniques is unknown. Purpose The purpose of this pilot clinical study was to clinically monitor and compare the regeneration of the gingival tissue by using 2 methods of gingival displacement in the same participant: the mechanical-chemical technique with double cords impregnated with aluminum chloride and the 810 nm diode laser (Odyssey; Ivoclar Vivadent AG). Material and methods A total of 6 participants needing 2 crowns on natural teeth were included in this study. At the first visit, the teeth were prepared with a 0.5-mm subgingival finishing line and interim crowns were fabricated. One of the teeth was randomly assigned to the double cord technique with 2 (# 000 and # 1) impregnated 5% aluminum chloride cords and the other to the 810 nm diode laser. An adjacent tooth served as a control. A device was made that would function as a fixed reference point for the measurements at different time intervals. A notch was created on the device to position the digital ruler between the occlusal notch and the free gingival margin to measure the distances. The measurements were recorded for each patient before displacement of the gingiva and at the time of cementation of the definitive crowns. The patients were followed at 1 week, 3 weeks, and 8 weeks after cementation of the definitive crowns. Results The amount of recession with the cord impregnated with aluminum chloride was 0.26 mm 8 weeks after cementation of the definitive crowns with a range between 0.00 mm and 0.72 mm. The diode laser showed an average recession of 0.27 mm with a range between 0.01 mm and 0.68 mm. Conclusions This study found an average loss of gingival height of 0.26 mm for the double cord technique and 0.27 mm for the laser. The amount of recession was considered not clinically significant.

Mass distribution of different infectious diseases appears even more likely in dentistry than other medical specialities. The purpose of the study is to examine different impressions with alginate materials in order to demonstrate the contamination with different pathogens. Material and method. 63 patients were included in this study. They required specific prosthetic treatment. Preliminary impression were obtained with irreversible hydrocolloid material and microbiologically tested shorthy after removal from the mouth, after washed throughly with cold water and after decontamination with specific desinfectants. Results. Microbiologic records on the alginate impressions in different stages, revealed a reduction in number of bacteria, but not completely absence, regardless of the type of decontamination substance. Conclusions. The presence of different pathogens on the surface of irreversible hydrocolloid impresions is certain. There are residual bacteria which differ from one substance to another, irrespective of cleaning stages and decontamination materials used in daily manipulation of dental impresion. Even if time consuming, decontamination of alginate impression is compulsory in dentistry.

The purpose of this study was to evaluate two types of impression materials which were frequently used for casting three-dimensional tool marks in China, namely (i) dental impression material and (ii) special elastomeric impression material for tool mark casting. The two different elastomeric impression materials were compared under equal conditions. The parameters measured were dimensional accuracies, the number of air bubbles, the ease of use, and the sharpness and quality of the individual characteristics present on casts. The results showed that dental impression material had the advantage of special elastomeric impression material in casting tool marks in crime scenes; hence, it combined ease of use, dimensional accuracy, sharpness and high quality.

Purpose: This study compared tissue three-dimensional (3D) displacements during the material setting phase of two maxillary impression tray-holding techniques: clinician manual pressure and patient occlusal pressure. Materials and Methods: The resultant two maxillary casts for each of 10 edentulous patients were compared using an optical 3D measurement system. Results: The junction between the hard and soft palates acted like a rotation center during impression making. The vertical displacements were significantly lower and posteriorly set when the impression was taken with the patient’s occlusion, in contrast to being located at the anterior two-thirds during the manual impression technique. Conclusion: Use of patient’s occlusion as a tray-holding technique may be preferred during the material setting phase of maxillary impressions.

The computer-aided design (CAD) and computer-aided manufacturing (CAM) process chain for dental restorations starts with taking an impression of the clinical situation. For this purpose, either extraoral digitization of gypsum models or intraoral digitization can be used. Despite the increasing use of dental digitizing systems, there are only few studies on their accuracy. Objective This study compared the accuracy of various intraoral and extraoral digitizing systems for dental CAD/CAM technology. Material and Methods An experimental setup for three-dimensional analysis based on 2 prepared ceramic master dies and their corresponding virtual CAD-models was used to assess the accuracy of 10 extraoral and 4 intraoral optical non-contact dental digitizing systems. Depending on the clinical procedure, 10 optical measurements of either 10 duplicate gypsum dies (extraoral digitizing) or directly of the ceramic master dies (intraoral digitizing) were made and compared with the corresponding CAD-models. Results The digitizing systems showed differences in accuracy. However, all topical systems were well within the benchmark of ±20 µm. These results apply to single tooth measurements. Conclusions Study results are limited, since only single teeth were used for comparison. The different preparations represent various angles and steep and parallel opposing tooth surfaces (incisors). For most digitizing systems, the latter are generally the most difficult to capture. Using CAD/CAM technologies, the preparation angles should not be too steep to reduce digitizing errors. Older systems might be limited to a certain height or taper of the prepared tooth, whereas newer systems (extraoral as well as intraoral digitization) do not have these limitations.

To compare the fit of all-ceramic crowns fabricated from conventional silicone impressions with the fit of all-ceramic crowns fabricated from intraoral digital impressions. Thirty patients with 30 posterior teeth with a prosthetic demand were selected. Zirconia-based ceramic crowns were made using an intraoral digital impression system (Ultrafast Optical Sectioning technology) (digital group, D) and 2-step silicone impression technique (conventional group, C). To replicate the interface between the crown and the preparation, each crown was cemented on its corresponding clinical preparation using ultra-flow silicone. Each crown was embedded in resin to stabilize the registered interface. Specimens were sectioned in buccolingual orientation, and internal misfit was measured at different areas using stereomicroscopy (×40). Data was analysed using Student’s t test and Mann-Whitney test (α = 0.05). No statistically significant differences were found (P > 0.05) between two groups. The mean internal misfit and mean marginal misfit were 170.9 μm (SD = 119.4)/106.6 μm (SD = 69.6) for group D and 185.4 μm (SD = 112.1)/119.9 μm (SD = 59.9) for group C. Ceramic crowns fabricated using an intraoral scanner are comparable to elastomer conventional impressions in terms of their marginal and internal fits. The mean marginal fit in both groups was within the limits of clinical acceptability. Impressions based on Ultrafast Optical Sectioning technology can be used for manufacturing ceramic crowns in a normal workflow, with the same results as silicone conventional impressions.

The transfer of infectious microorganisms between patient, doctor and auxiliary staff is called ‘cross infection’. Due to the applications and materials used in prosthetic treatments, prosthodontists, nurses and dental technicians come up against several infections which can be transmitted from patients. The delivery of dental impressions, obtained from patients during prosthetic applications, without disinfection leads to cross contamination between clinic and dental laboratory. To prevent contamination, disinfection of dental impressions is recommended. However, disinfection methods and disinfectants can affect the characteristics of dental impression materials. The aim of this paper is to review the disinfection of dental impressions and the effects of disinfectants on dental impressions in the light of previous studies.

The custom gingival mask technique duplicates the tissue contours created by an implant-supported fixed interim prosthesis, which has been verified for satisfactory esthetics, phonetics, hygiene access, and patient comfort. This allows the dental laboratory technician to accurately duplicate the contours of the interim prosthesis in the definitive prosthesis. The technique described also incorporates a cast verification step to ensure the accurate, passive fit of the definitive prosthesis while eliminating the duplicate impression copings and implant replicas typically required for a verification cast.