Integração dos componentes curriculares Escultura Dental e Prótese Parcial Removível no desenvolvimento de material didático auxiliar para a pré-clínica / Integración de los componentes curriculares Escultura Dental y Prótesis Parcial Removible en el desarrollo de material didáctico auxiliar para el preclínico / Integration of Dental Sculptureand Removable Partial Denture courses in developing instructional material for pre-clinical use

O objetivo deste relato de experiência foi integrar os componentes curriculares Escultura Dental e Prótese Parcial Removível por meio da confecção de macromodelos com nichos em dentes anteriores e posteriores a serem usados como material didático auxiliar.A metodologia teve abordagem descritiva. Foram confeccionados macromodelos em cera dos seguintes elementos dentários: caninos superiores e inferiores, pré-molar superior e molares superiores e inferiores. Em seguida, nichos foram preparados nos elementos,reproduzindo as características da etapa de Preparo de Boca Tipo II ou Protético. Macromodelos com as características individuais de nichos oclusais simples e duplo (interdental) em dentes posteriores foram obtidos, bem como com nichos em cíngulos, tanto confecionados por desgaste como por acréscimo. Diante do conhecimento da anatomia dental e a habilidade manual desenvolvidos na Escultura Dental, os macromodelos confeccionados permitiram uma melhor visualização das características morfológicas dos nichos,sendo considerado um recurso complementar no processo ensino-aprendizagem em Prótese Parcial Removível (AU).

El objetivo de este relato de experiencia fue integrar los componentes curriculares Escultura Dental y Prótesis Parcial Removible mediante la creación de macromodelos con nichos en dientes anteriores y posteriores para ser utilizados como material didáctico auxiliar. La metodología tuvo un enfoque descriptivo. Se realizaron macromodelos en cera de los siguientes dientes: caninos superiores e inferiores, premolares superiores y molares superiores e inferiores. A continuación, se prepararon nichos en los elementos, reproduciendo las características de la etapa de Preparación de la Boca Tipo II o Prótesis. Se obtuvieron macromodelos con las características individuales de nichos oclusales simples y dobles (interdentales) en dientes posteriores, así comonichos en cingulados, ambos creados por desgaste y adición. Dado el conocimiento de la anatomía dental y la habilidad manual desarrollada en la Escultura Dental, los macromodelos realizados permitieron una mejor visualización de las características morfológicas de los nichos, considerándose un recurso complementario en el proceso de enseñanza-aprendizaje en Prótesis Parcial Removible (AU).

The objective of this experience report was to integrate the curricular components of Dental Sculpture and Removable Partial Dentures through the creation of macromodels with rest seat in anterior and posterior teeth to be used as auxiliary teaching material. The methodology had a descriptive approach. Wax macromodels were made of the following teeth: upper and lower canines, upper premolar and upper and lower molars. Next, rest seats were prepared in the elements, reproducing the characteristics of the Type II or Prosthetic Mouth Preparation stage. Macromodels with the individual characteristics of single and double (interdental) occlusal rest seats in posterior teeth were obtained, as well as rest seats in cingulum, both created by wear and with composites. Given the knowledge of dental anatomy and the manual skill developed in Dental Sculpture, the macromodels made enabled better visualization of the morphological characteristics of the rest seats, being considered a complementary resource in the teaching-learning process in Removable Partial Prosthesis (AU).

Internal fit of three-unit fixed dental prostheses produced by computer-aided design/computer-aided manufacturing and the lost-wax metal casting technique assessed using the triple-scan protocol.

Suboptimal adaptation of fixed dental prostheses (FDPs) can lead to technical and biological complications. It is unclear if the computer-aided design/computer-aided manufacturing (CAD/CAM) technique improves adaptation of FDPs compared with FDPs made using the lost-wax and metal casting technique. Three-unit FDPs were manufactured by CAD/CAM based on digital impression of a typodont model. The FDPs were made from one of five materials: pre-sintered zirconium dioxide; hot isostatic pressed zirconium dioxide; lithium disilicate glass-ceramic; milled cobalt-chromium; and laser-sintered cobalt-chromium. The FDPs made using the lost-wax and metal casting technique were used as reference. The fit of the FDPs was analysed using the triple-scan method. The fit was evaluated for both single abutments and three-unit FDPs. The average cement space varied between 50 µm and 300 µm. Insignificant differences in internal fit were observed between the CAD/CAM-manufactured FDPs, and none of the FPDs had cement spaces that were statistically significantly different from those of the reference FDP. For all FDPs, the cement space at a marginal band 0.5-1.0 mm from the preparation margin was less than 100 µm. The milled cobalt-chromium FDP had the closest fit. The cement space of FDPs produced using the CAD/CAM technique was similar to that of FDPs produced using the conventional lost-wax and metal casting technique.

Marginal and internal fit of metal copings fabricated with rapid prototyping and conventional waxing.

STATEMENT OF PROBLEM: Given the limitations of conventional waxing, computer-aided design and computer-aided manufacturing (CAD-CAM) technologies have been developed as alternative methods of making patterns. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit of metal copings derived from wax patterns fabricated by rapid prototyping (RP) to those created by the conventional handmade technique. MATERIAL AND METHODS: Twenty-four standardized brass dies were milled and divided into 2 groups (n=12) according to the wax pattern fabrication method. The CAD-RP group was assigned to the experimental group, and the conventional group to the control group. The cross-sectional technique was used to assess the marginal and internal discrepancies at 15 points on the master die by using a digital microscope. An independent t test was used for statistical analysis (α=.01). RESULTS: The CAD-RP group had a total mean (±SD) for absolute marginal discrepancy of 117.1 (±11.5) µm and a mean marginal discrepancy of 89.8 (±8.3) µm. The conventional group had an absolute marginal discrepancy 88.1 (±10.7) µm and a mean marginal discrepancy of 69.5 (±15.6) µm. The overall mean (±SD) of the total internal discrepancy, separately calculated as the axial internal discrepancy and occlusal internal discrepancy, was 95.9 (±8.0) µm for the CAD-RP group and 76.9 (±10.2) µm for the conventional group. The independent t test results showed significant differences between the 2 groups. The CAD-RP group had larger discrepancies at all measured areas than the conventional group, which was statistically significant (P<.01). CONCLUSIONS: Within the limitations of this in vitro study, the conventional method of wax pattern fabrication produced copings with better marginal and internal fit than the CAD-RP method. However, the marginal and internal fit for both groups were within clinically acceptable ranges.

Marginal and internal fit of pressed ceramic crowns made from conventional and computer-aided design and computer-aided manufacturing wax patterns: An in vitro comparison.

STATEMENT OF PROBLEM: To our knowledge, no studies have evaluated the influence of the wax fabrication technique on the internal adaptation and marginal accuracy of pressed ceramic single crowns. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit of a lithium disilicate crown fabricated either from conventional waxing or from a subtractive milled wax pattern. MATERIAL AND METHODS: Ten silicone impressions were made for a maxillary canine prepared to receive a complete crown. Two pressed lithium disilicate glass ceramic copings were made on the die poured from each impression. The first was from a conventional wax pattern and the second from milled wax blocks. The replica technique was used to measure the fit by scanning electron microscope at ×80 magnification. Collected data were analyzed with the paired Student t test for the marginal and wall fit. For the occlusal fit, the difference in scores did not follow a normal distribution, and the Wilcoxon signed ranks test was used (α=.05). RESULTS: The mean values +SD were 170.3 ±50.7 µm for the marginal fit and 130.3 ±21.6 µm for the internal fit with the conventional technique. For the computer-aided design and computer-aided manufacturing (CAD-CAM) technique, they were 105.1 ±39.6 µm and 98.1 ±26.1 µm. Statistical significance was found for the marginal and internal fit (P<.05). The occlusal fit median and interval interquartile scores were 305.0 µm (269.9 to 334.4) for conventional fabrication and 199.0 µm (141.5 to 269.9) for subtractive manufacturing. The differences were not statistically significant (P>.05). CONCLUSIONS: The subtractive CAD-CAM waxing technique resulted in the improved fit of a pressed lithium disilicate crown by decreasing the marginal discrepancies and internal adaptation.

Marginal adaptation of four inlay casting waxes on stone, titanium, and zirconia dies.

STATEMENT OF PROBLEM: Different inlay casting waxes do not produce copings with satisfactory marginal accuracy when used on different die materials. PURPOSE: The purpose of this study was to evaluate the marginal accuracy of 4 inlay casting waxes on stone dies and titanium and zirconia abutments and to correlate the findings with the degree of wetting between the die specimens and the inlay casting waxes. MATERIAL AND METHODS: The inlay casting waxes tested were Starwax (Dentaurum), Unterziehwachs (Bredent), SU Esthetic wax (Schuler), and Sculpturing wax (Renfert). The marginal opening of the waxes was measured with a stereomicroscope on high-strength stone dies and on titanium and zirconia abutments. Photographic images were obtained, and the mean marginal opening for each specimen was calculated. A total of 1440 measurements were made. Wetting between die materials and waxes was determined after fabricating stone, titanium, and zirconia rectangular specimens. A calibrated pipette was used to place a drop of molten wax onto each specimen. The contact angle was calculated with software after an image of each specimen had been made with a digital camera. Collected data were subjected to a 2-way analysis of variance (α=.05). Any association between marginal accuracy and wetting of different materials was found by using the Pearson correlation. RESULTS: The wax factor had a statistically significant effect both on the marginal discrepancy (F=158.31, P<.001) and contact angle values (F=68.09, P<.001). A statistically significant effect of the die material factor both on the marginal adaptation (F=503.47, P<.001) and contact angle values (F=585.02, P<.001) was detected. A significant correlation between the marginal accuracy and the contact angle values (Pearson=0.881, P=.01) was also found. CONCLUSIONS: Stone dies provided wax copings with the best marginal integrity, followed by titanium and zirconia abutments. Unterziehwachs (Bredent), wax produced the best marginal adaptation on different die materials. A significant correlation was found between the marginal accuracy and the contact angle values. As the contact angle value became smaller, the marginal accuracy improved. All combinations of waxes and stone and titanium dies presented a high wettability.

Comparison of changes in dental and bone radiographic densities in the presence of different soft-tissue simulators using pixel intensity and digital subtraction analyses.

OBJECTIVES: To evaluate the influence of soft-tissue simulation materials on dental and bone tissue radiographic densities using pixel intensity (PI) and digital subtraction radiography (DSR) analyses. METHODS: 15 dry human mandibles were divided into halves. Each half was radiographed using a charge-coupled device sensor without a soft-tissue simulation material (Wm) and with 5 types of materials: acrylic (Ac), wax (Wx), water (Wt), wood (Wd) and frozen bovine tissue (Bt). Three thicknesses were tested for each material: 10 mm, 15 mm and 20 mm. The material was positioned in front of the mandible and the sensor parallel to the molar region. The radiation beam was perpendicular to the sensor at 30 cm focal spot-to-object distance. The digital images of the bone and dental tissue were captured for PI analyses. The subtracted images were marked with 14 landmark magnifications, and 2 areas of analyses were defined, forming the regions of interest. Shapiro-Wilk and Kruskal-Wallis tests followed by Dunn's post-test were used (p < 0.05). RESULTS: DSR showed that both the material type and the thickness tested influenced the gain of density in bone tissue (p < 0.05). PI analyses of the bone region did not show these differences, except for the lower density observed in the image without soft-tissue simulation material. In the dental region, both DSR and PI showed that soft-tissue simulators did not influence the density in these regions. CONCLUSIONS: This study showed that the materials evaluated and their thicknesses significantly influenced the density-level gain in alveolar bone. In dental tissues, there was no density-level gain with any soft-tissue material tested.

Improvement in Ti-porcelain bonding by SiO(2) modification of titanium surface through cast method.

This study aimed to improve Ti-porcelain bonding strength through SiO2 modifications. Wax patterns were coated with SiO2 mixed with tetraethoxy silane (group C), patterns without coating were used as controls and subdivided into sandblasting group (group S) and polishing group (group P). Castingsurfaces were analyzed with XRD, while Ti-ceramic interfaces were characterized using SEM/EDS. Metal-ceramic specimens were tested in three point bending, and characterizations were also analyzed with SEM/EDS of porcelain debonding surfaces. In group C, SiO2 and Ti5Si3 phases were observed; SEM micrograph showed that Ti-porcelain had a compacted interface, and EDS maps of the interface illustrated the diffusion of Si, Al, and Sn to Ti, and cohesive fracture within the bonding agent. The bond strength of group C was 39.04±5.0 MPa, which was 15% higher than that of group S and 32% higher than that of group P. SiO2 coating could improve Ti-porcelain bond strength.

A simple method to fabricate stabilized record bases: a modified approach using casting wax for the borders.

Retention and stability of a record base is often compromised in the mouth because of blockout procedures performed before adapting a record base material on a definitive cast. This article presents a technique of fabricating a stable and retentive record base, in which a definitive cast does not receive a blockout procedure so that the record base engages the facial undercuts in the cast by means of a green coloured inlay casting wax.

A comparison of the accuracy of patterns processed from an inlay casting wax, an auto-polymerized resin and a light-cured resin pattern material.

BACKGROUND: Traditionally, inlay casting waxes have been used to fabricate patterns for castings. Newer resin pattern materials offer greater rigidity and strength, allowing easier laboratory and intraoral adjustment without the fear of pattern damage. They also claim to possess a greater dimensional stability when compared to inlay wax. AIMS: This study attempted to determine and compare the marginal accuracy of patterns fabricated from an inlay casting wax, an autopolymerized pattern resin and a light polymerized pattern resin on storage off the die for varying time intervals. MATERIALS AND METHODS: Ten patterns each were fabricated from an inlay casting wax (GC Corp., Tokyo, Japan), an autopolymerized resin pattern material (Pattern resin, GC Corp, Tokyo, Japan) and a light-cured resin pattern material (Palavit GLC, Hereaus Kulzer GmbH, Germany). The completed patterns were stored off the die at room temperature. Marginal gaps were evaluated by reseating the patterns on their respective dies and observing it under a stereomicroscope at 1, 12, and 24 h intervals after pattern fabrication. RESULTS: The results revealed that the inlay wax showed a significantly greater marginal discrepancy at the 12 and 24 h intervals. The autopolymerized resin showed an initial (at 1 h) marginal discrepancy slightly greater than inlay wax, but showed a significantly less marginal gap (as compared to inlay wax) at the other two time intervals. The light-cured resin proved to be significantly more dimensionally stable, and showed minimal change during the storage period. CONCLUSION: The resin pattern materials studied, undergo a significantly less dimensional change than the inlay waxes on prolonged storage. They would possibly be a better alternative to inlay wax in situations requiring high precision or when delayed investment (more than 1 h) of patterns can be expected.

Simplified technique for orbital prosthesis fabrication: a clinical report.

Loss of orbital content can cause functional impairment, disfigurement of the face, and psychological distress. Rehabilitation of an orbital defect is a complex task, and if reconstruction by plastic surgery is not possible or not desired by the patient, the defect can be rehabilitated by an orbital prosthesis. The prosthetic rehabilitation in such cases depends on the precisely retained, user-friendly removable maxillofacial prosthesis. Many times, making an impression of the orbital area with an accurate record of surface details can be a difficult procedure. The critical areas are making a facial moulage, mold preparation, and attaching the retention device, particularly when eyeglass frames are used. This case focuses on these hindrance factors. A simple basket was used for the impression tray to obtain the facial moulage. A putty mold was used, and attachment of the prosthesis to a retention device was accomplished with positional distance. This method proves to be an economical and simple way of making an orbital prosthesis.

An alternative approach in fabrication of fixed complete dentures using a duplicate denture.

The traditional prosthetic steps in the fabrication of a fixed complete denture after implant osseointegration include final impression, verification of implant positioning in the working cast, mounting of the working cast, and mock denture wax trial insertion prior to the laboratory fabrication of the metal substructure; however, in patient scenarios of immediate loading of implants, the interim conversion prosthesis can be used to advance from the final impression to the milling of the underlying framework in one appointment. Consistency in the initial wax trial insertion, radiographic guide, and intraoral positioning of the conversion prosthesis can result in a well-designed definitive prosthesis in less time with the use of the existing duplicate complete denture.

Cera para fixação de dentes

Cera desenvolvida com objetivo de fixar dentes nos trabalhos de Prótese Total (PT) , Prótese Parcial Removível (PPR) e em barras de protocolos sobre implantes verificando-se a não soltura dos mesmos durante a prova estética e funcional. Trata-se de uma cera exclusiva para esta finalidade

A study of multiple bitemarks inflicted in human skin by a single dentition using geometric morphometric analysis.

Criticisms of the forensic discipline of bitemark analysis state that the range of distortion in the shape of bitemark impressions in skin has not been scientifically established. No systematic statistical studies exist that explore this problem. As a preliminary investigation of this issue, a single dentition was mounted in a mechanical apparatus and used to create 89 bitemarks in human cadaver skin, both parallel and perpendicular to tension lines. Impressions of the same dentition were also created in wax. 2D scanned images of the biting dentition were obtained. Locations of incisal edges of all 6 anterior teeth as well as the midpoint of the canine were captured as landmarks in all specimens. This set of landmark data was then studied using established geometric morphometric methods. All specimen shapes were compared using Procrustes superimposition methods, and by a variation of Procrustes superimposition which preserves scale information. Match criteria were established by examining the range of variation produced by repeated measurements of the dentition for each class of specimen. The bitemarks were also compared to a population of 411 digitally scanned dentitions, again using the match criteria. Results showed that bitemarks in wax had lower measurement error than scanned images of the dentition, and both were substantially lower than measurement error as recorded in skin. None of the 89 bitemarks matched the measured shape of the biting dentition or bitemarks in wax, within the repeated measurements error level, despite the fact that all bitemarks were produced by this dentition. Comparison of the bitemarks to the collection of 411 dentitions showed that the closest match to the bitemarks was not always the same dentition that produced the bitemarks. Examination of Procrustes plots of matched shapes showed non-overlapping distributions of measurements of bitemarks in skin, wax, and the dentition. All had statistically significant differences in mean shape. Principal component analysis (PCA) and canonical variates analysis (CVA) both showed clear segregation of the three types of data. The patterns of variance revealed by PCA showed several distinct patterns produced by skin distortion; alteration of relative arch width, and varying displacement of non-aligned teeth in the dentition. These initial results indicate that when multiple suspects possess similar dentitions, bitemark analysis should be approached with caution.

Avaliação in vitro da adaptação marginal de restaurações indiretas de resinas compostas e cerâmica feldspática / In vitro evaluation of marginal adaptation of indirected restorations of composite resin and feldspathic ceramics

Objetivo: Avaliar a adaptação marginal de restaurações indiretas inlay de resinas compostas e cerâmica feldspática. Métodos: Foi utilizado um troquel metálico com preparo cavitário oclusoproximal, que foi moldadocom silicona de adição e o molde, vazado com gessopedra tipo IV. Dez restaurações em resinas compostasVita Zeta, Dialog II e Solidex foram confeccionadas pela técnica incremental, com três ciclos de ativaçãode 180s utilizando uma unidade de luz UniXS. Vinte restaurações de cerâmica feldspática Noritake EX-3 foram confeccionadas, sendo dez pela técnica convencional e dez pela técnica de pressão positiva de presa do revestimento refratário. Para verificação da adaptação marginal, as restaurações foram inseridas no troquelmetálico com um peso de 1,0 Kg e realizadas dez leituras na parede gengival da caixa proximal por meiode microscópio comparador MitutoyoTM, sendo os dados submetidos à análise estatística (Anova) para avaliação da adaptação marginal entre as marcas de resina composta e t-student para avaliação da variação técnicas de obtenção do modelo refratário. Resultados e conclusão: Não houve diferença estatisticamente significativana adaptação marginal entre as restaurações de resinas compostas e a cerâmica feldspática (p = 0,279), nem entre a técnica convencional e de pressão positiva de presa do revestimento refratário ( p = 0,385)

Técnica incremental para resinas compostas - anteriores superiores / Incremental technique for composite resins - upper anterior teeth

O conhecimento detalhado da anatomia dentária é peça chave para a formação de um cirurgião-dentista qualificado. O material mais apropriado para um primeiro contato com os conceitos da anatomia dentária é certamente a cera. Esse material proporciona ao cirurgião-dentista o desenvolvimento da motricidade fina e da percepção de detalhes de forma, função e estética. A resina composta, material de uso frequente nos consultórios odontológicos, exige muito mais técnica para ser aplicada corretamente e para que seu potencial seja adequadamente explorado. Tendo em vista que a técnica de enceramento incremental já foi entendida e praticada, este protocolo de aplicação de resina composta é o passo subsequente, visto que os mesmos princípios aplicados à cera serão demonstrados em resina composta.

Reproduction of intra-radicular surface anatomy of extracted human teeth: comparison of three different materials using injection technique.

This in vitro study compared the reproduction of intra-radicular surface anatomy of extracted human teeth taken by silicon, inlay casting wax and acrylic resin using an injection technique to determine which material produced fewer voids. Twenty impressions/patterns using this technique were made for each material and compared with each other on the basis of number, location and size of voids. Length of each dowel impression/ pattern was also compared. The percentage of void free surfaces using silicon, inlay casting wax and acrylic resin were 90%, 100% and 85% respectively. Most of the voids were less than 1mm in size and situated in the middle third of the impression/pattern. There was no significant difference in the length of the impression/ pattern taken by the three materials. Using the injection technique to reproduce the intra-radicular anatomy of the dowel space, all three materials will show predictably good results.

Periauricular mold brachytherapy.

PURPOSE: We present a patient with recurrent basal cell carcinoma (BCCA) who was treated with custom-made mold brachytherapy. METHODS AND MATERIALS: The patient was admitted to the hospital with the complaint of recurrent BCCA of the auditory canal. He has previously treated by surgery and external beam radiotherapy. We decided to continue with reirradiation to tumor bed after surgical excision. A total of 25 Gy to 5mm depth of surgical bed was delivered by mold brachytherapy. RESULTS: The patient did well during the treatment without any acute toxicity. He was lost to followup after 2 years of treatment without any obvious late morbidity. CONCLUSION: Custom-made mold brachytherapy is an alternative treatment modality, for reirradiation of selected group of patients, with minimal morbidity and good disease control.

Long-term survivals of 'direct-wax' cast gold onlays: a retrospective study in a general dental practice.

BACKGROUND AND OBJECTIVES: Compared to other restoration types, indirect cast posterior restorations of partial coverage exhibit one of the longest survivals. The purpose of the current study was to estimate the success rates of 'direct-wax' cast gold onlays. According to the direct wax technique, the wax pattern is shaped intra-orally followed by direct casting without the need for impressions, resulting in low cost and short processing time. DESIGN AND METHODS: A retrospective survival study was undertaken at a mixed National Health Service and private general dental practice based in London. Patients with direct-wax onlays attending over a period of four months for regular check-ups or dental treatment were recruited. Patient discomfort, pain or sensitivity was recorded. Restoration location, extension, marginal fit, and tooth vitality were also recorded. Restoration failure was defined in the event of recurrent caries, pulp infection for vital teeth, increase in the size of periapical radiolucency for non-vital teeth, and restoration decementation. Survival estimates were calculated using the Kaplan-Meier algorithm. RESULT: One hundred and ninety-four onlays in 56 patients were examined. Four restorations (2.1%) had failed, mainly due to recurrent caries. The cumulative survival probability was estimated at 415.3 (95% Confidence Interval: 403.0, 427.7) months (34.6, 95% CI: 33.6, 35.6 years), while the 10-year and 20-year survival rates were 97.0% and 94.1% respectively. Vital teeth, compared to non-vital ones, and onlay extension encompassing both the mesial and distal tooth surfaces exhibited significantly (P <0.05) higher success rates. Variations in marginal fit and restoration location did not affect the survival probability. CONCLUSION: Direct-wax cast gold restorations of partial coverage were a highly successful treatment option for posterior restorations in a general dental practice environment.