In Vitro Microscopic Evaluation of Metal- And Zirconium-Oxide-Based Crowns' Marginal Fit

ABSTRACT Objective To evaluate the marginal adaptation of computer-aided designing and computer-aided machining (CAD/CAM) fabricated cobalt-chromium and zirconium-oxide-based ceramic crowns compared to those produced by a conventional method. Material and Methods The study consists of three groups; 45 crowns fabricated from cobalt-chromium (CAD-CoCr) and 45 crowns manufactured from zirconium CAD/CAM technology (CAD-Z), and 45 control (C) which consists of conventional metal-ceramic crowns. The marginal discrepancies in vertical dimensions were assessed utilizing a microscope in four surfaces (mesial, distal, vestibular, and oral) for each crown. On completion of the microscopic evaluation, multivariate analysis of variance (MANOVA) was used to study the difference in the four surfaces, considered altogether. Two-way ANOVA revealed the effect of three systems used for gap measurements of each landmark. The differences observed were considered significant at p<0.05. Results There were no differences in the four surfaces revealed by АNOVА in the three groups when considered altogether. Two-way ANOVA of each surface discovered no differences among all groups as well. Conclusion The CAD/CAM crowns revealed a comparable and satisfactory marginal adaptation compared to conventional metal-ceramic crowns.

Brazilian Adults Believe that Complete Dentures would be the Solution to the Oral Impacts Caused by Reduced Dentition

Abstract Objective: To evaluate the direct and oral impact-mediated association between reduced dentitions and the self-perceived need for complete dentures (CD) in dentate adults. Material and Methods: Data from the Brazilian Oral Health Survey (2010) were analyzed. The outcome was self-perceived need for CD. Functional dentition (FDClassV) was defined by the presence of the following criteria: level I - ≥1 tooth in each arch, level II - 10 teeth in each arch, level III - 12 anterior teeth, level IV - ≥ 3 posterior occluding pairs (POPs) of premolars and level V - ≥1 bilateral POPs of molars. Oral impacts were assessed with Oral Impacts on Daily Performances scale. Results: FDClassV was associated with a less self-perceived need for CD both directly and mediated by oral impacts. Dentitions without level V were associated with the outcome mediated by oral impacts. Between individuals with 10 teeth in each arch, self-perceived need for CD was similar for those who had or not anterior teeth and POPs. Individuals with <10 teeth in each arch and level III did not have a higher frequency of self-perceived need for CD compared to those with level II. Conclusion: Oral impacts mediated the association between reduced dentitions and self-perceived need for CD. Individuals with tooth loss may report need for CD, even when they have dental configurations compatible with functionality.

The Prosthetic Management of a Case of Epulis Fissuratum by a Novel Technique / El manejo protésico de un caso de épulis fisurado con una técnica novedosa

ABSTRACT: The clinical management of the epulis involves the elimination of causal factors, excision of fibrous tissue excess accompanied by an appropriate prosthetic rehabilitation. The confection of interim prosthesis or the rectification of old prosthesis for the setting up of a tissue conditioner if necessary, to improve the healing and prevent the decrease of the vestibule depth after the surgical exeresis. Throughout this paper, we are going to present a new technique for the correction of old prostheses poorly adapted for the management of a case of the epulis fissuratum.

RESUMEN: El manejo clínico de un épulis comprende la eliminación de los agentes causales y la eliminación del tejido fibroso, acompañado de una adecuada rehabilitación protésica. Es necesaria la confección de una prótesis provisional o la rectificación de la prótesis vieja, para la colocación del acondicionador de tejidos si fuera necesario para mejorar el sanado y prevenir la disminución de la profundidad del vestíbulo después de la exéresis quirúrgica. En este artículo, presentaremos una nueva técnica para la corrección de la prótesis desajustada en el manejo de un caso de épulis fisurado.

Characteristics of Periodontal Tissues in Prosthetic Treatment with Fixed Dental Prostheses.

The objective of the present study was to investigate the effects of various types of fixed prostheses on periodontal tissues and explore the association of gingival biotype and gum recession in relation to prosthesis types. The study participants (N = 95) were divided into three groups based on the type of dental prosthesis: Group-I: cobalt-chrome (Co-Cr) ceramic prosthesis fabricated by the conventional method (n = 35); Group-II: consisted of patients with Co-Cr ceramic prostheses fabricated by a computer-aided design and computer aided manufacturing (CAD/CAM) technique (n = 30); and Group-III: zirconia-based prostheses fabricated by the CAD/CAM technique (n = 30). Following the use of prostheses, periodontal examinations were performed using the Community Periodontal Index (CPI) and Modified Approximal Plaque Index (MAPI). In addition, the gingival biotype was examined using a probe transparency method. The Statistical Package for the Social Sciences (SPSS), Version 20 (IBM Company, Chicago, IL, USA), was used to analyze the results, and the significance level was set at p = 0.05. It showed the MAPI results after the use of prosthetic rehabilitation for 12 months of periodontitis in 87.9% ± 15.4 of patients in Group-I, in 80.6% ± 17.97 in those in Group-II, and in 62.5% ± 21.4 in those in Group-III (p < 0.01). The CPI index results indicated a high prevalence of periodontal disease in all groups. The number of people with healthy periodontium constituted 17.1% of patients in Group-I, 24.2% in Group-II, and 37.1% in Group-III. Our study concluded that prosthetic treatment with periodontal diseases showed better outcomes while using dental prostheses fabricated by the CAD/CAM technique compared to the conventionally fabricated dental prostheses. The thin gingival biotype is more often associated with gingival recession than the thick biotype.

Self-Perception on the Institutionalized Elderly Need of Dental Prosthesis

Abstract Objective: To make an association between self-perception and the implementation of sociodemographic variables for the autonomous and / or partially dependent individuals in nursing homes. Material and Methods: Epidemiological, observational and cross-sectional study. The sample consisted of 208 institutionalized elderly, both sexes, 60 years old or older, independent or partially dependent, randomly selected from two long-term residential institutions. Subjective evaluation: self-perception questionnaire, Geriatric Oral Health Assessment Index, quality of life assessment, Oral Impacts on Daily Performance (OIDP), oral health self-assessment (OH) and the need for dental prostheses. Bivariate analysis, chi-square test and multiple logistic regression were used, with the variables with p<0.05 remaining in the model. Results: Men were edentulous (53.43%), 68.75% used some type of denture, and 64.91% required dental prostheses, 60.58% self-assessed (OH) as good / excellent; who reported a need for dental prostheses presented 6.7 times (95% CI: 3.2-14.3) and more likely to have an impact on OIDP, those who needed prosthetics had a 2.8 times chance (95% CI: 1.3-6.1) (p<0.0001). The self-reported need for prostheses was associated with prevalence severity of impacts on QoL, eating, pronounce words correctly, Smile without feeling embarrassed; and the main reasons for not having badly adjusted teeth / dentures. Conclusion: The institutionalized elderly self-perceive the need for dental prostheses, but it does not have a negative impact on quality of life.

Tiempo de elaboración y grado de deformidad de la placa base termoformada, en comparación con la placa base de acrílico de autopolimerización / Development time and the deformity degree of the thermoformed base plate compared to the acrylic base plate of self-polymerization

Resumen Introducción: En la actualidad existen diversos tipos de materiales para la confección de placas bases, como procedimiento para la confección de prótesis dentales. La opción de la lámina de termoformado actualmente es de poco uso, el acrílico de autopolimerización es un material de uso diario en consulta. Objetivo: Comparar las técnicas de confección de placas bases, para determinar cuál de las dos brinda cualidades como menor tiempo de elaboración y menor deformidad. Materiales y métodos: Se seleccionaron por conveniencia 20 modelos de yeso totalmente edéntulos, a los cuales se registra tiempo de elaboración y se les aplican las mismas pruebas de laboratorio. Resultados: Las placas bases termoformadas presentan un tiempo medio de 7 minutos, mientras que las placas bases de acrílico de autopolimerización muestran un tiempo medio de 29 minutos, con base en los análisis de laboratorio la menor deformación se presenta en la placa base de acrílico de autopolimerización. Conclusión: El tiempo de elaboración de la placa base termoformable es menor, mientras que la deformación es mayor en comparación con la de la placa base de autopolimerización, y esta última a su vez, presenta mayor tiempo de elaboración que el de la placa base termoformable.

Abstract Introduction: Currently there are different types of materials for the preparation of base plates, as a procedure for the preparation of dental prostheses. The option of the thermoforming sheet, which is currently of little use, as well as, of self-curing acrylic, a material of daily use in consultation. Objective: To compare the techniques for making base plates, to determine which of the two provide qualities such as shorter processing time and less deformity. Materials and methods: 20 models of gypsum totally edentulous were selected for convenience, to which processing time is recorded and the same laboratory tests are applied. Results: The thermoformed base plates have an average time of 7 minutes, while the self-polymerized acrylic base plates have an average time of 29 minutes, based on the laboratory analysis the least deformation occurs in the acrylic base plate of autopolimerization. Conclusion: The time of preparation of the thermoformable base plate is less, while the deformation is greater compared to the base plate of self-polymerizatíon, the latter in turn, has a longer processing time than the thermoformable base plate.

Prosthetic Correction of Proclined Maxillary Incisors: A Biomechanical Analysis.

In some cases of proclined maxillary incisors, the proclination can be corrected by a fixed prosthesis. The aim of this study was to investigate the magnitude and distribution of (i) principal stresses in the adjacent alveolar bone and (ii) direct and shear stresses that are normal and parallel, respectively, to the bone-tooth interface of a normal angulated maxillary incisor, a proclined one, and a proclined one corrected with an angled prosthetic crown. 2D finite-element models were constructed, and a static load of 200 N on the palatal surface of the maxillary incisor at different load angles was applied. Load angles (complementary angle to interincisal angle) ranging from 20° to 90° were applied. The results indicate that the load angle could have a more significant impact on the overall stress distributions in the surrounding alveolar bone and along the bone-tooth interface than the proclination of the maxillary incisor. Provided that the resulting interincisal angle is 150° or smaller, the stresses in the surrounding bone and at the bone-tooth interface are similar between a proclined maxillary incisor and the one with prosthodontic correction. Hence, such a correction, when deemed appropriate clinically, can be undertaken with confidence that there is little risk of incurring additional stresses over that already in existence, in the supporting bone and at the tooth-bone interface.

Fatigue and microgap behaviour of a three-unit implant-fixed dental prosthesis combining conventional and dynamic abutments.

This is an in vitro study composed by a fatigue test followed by an optical microscopy analysis. Dynamic abutments concept, recently introduced on screw-retained implant dental prosthesis, consists on the screw channel customisation according to the individual needs of each rehabilitation. Geometry and tightening torque differences advise the assessment of their mechanical performance. Clarify whether the combination of dynamic and conventional abutments in a three-unit implant-fixed prosthesis has detrimental effects either on the mechanical performance under cyclic loading or on the implant-abutment microgap dimensions. The fatigue test was performed in agreement with the ISO standard 14801. Then on the samples that resisted 5 million cycles, the implant-abutment microgap was measured on dynamic and conventional abutments using optical microscopy. Two unloaded samples were used as control group. The samples supported a load of 1050 N. The implant-abutment microgap measurement did not show statistically significant differences (p = .086) between loaded and unloaded groups, but the loaded conventional abutments showed a significant lower implant-abutment microgap (p = .05) than the loaded dynamic abutments. The combination of conventional and dynamic abutments do not seem to produce a decrease in fatigue resistance to a level below the mastication forces or an increase in the joint dimensions.

A device for testing the durability and exploitation reliability of dental prostheses.

PURPOSE: The aim of this work was to develop the design of the construction of a stand for testing the operational stability of dental prostheses, designed on the basis of an own idea. There are no devices that would make it possible to test complete structures, including the actual kinematics of motion and the influence of the environment of the oral cavity. MATERIALS AND METHODS: Presented were several devices used for testing both fixed and removable prostheses. Attention was paid to their limited possibilities in the area of the tested friction node, kinematics of motion, and the assessment of the influence of the environment of the oral cavity on the tested functional quality. The construction was based on the author's own ideas as well as on a review of the available literature. RESULTS: As the final result of the research, simplified images of the stand were presented along with their descriptions. CONCLUSIONS: The experimental verification of the stand allowed concluding that the research aims have been achieved. First of all, the device allows testing prosthetic structures of different sizes and it is possible to load the tested prostheses in randomly chosen points.

The use of Myerson Duracetal Obturators In the Rehabilitation of Maxillary Resection Defects

Myerson Duracetal, was used for the fabrication of Obturator Prostheses in four (4) patients. The steps in fabrication are outlined. The patients' perception of function as assessed using the Obturator Function Scale (Table 1) is also presented. Despite technical challenges, Myerson Duracetal was successfully used in fabrication of light, stable, retentive, aesthetic prostheses which could be adapted to the evolving defects.

Applications of Light Amplification by Stimulated Emission of Radiation (Lasers) for Restorative Dentistry.

Light amplification by stimulated emission of radiation (laser) has been used widely in a range of biomedical and dental applications in recent years. In the field of restorative dentistry, various kinds of lasers have been developed for diagnostic (e.g. caries detection) and operative applications (e.g. tooth ablation, cavity preparation, restorations, bleaching). The main benefits for laser applications are patient comfort, pain relief and better results for specific applications. Major concerns for using dental lasers frequently are high cost, need for specialized training and sensitivity of the technique, thereby compromising its usefulness particularly in developing countries. The main aim of this paper is to evaluate and summarize the applications of lasers in restorative dentistry, including a comparison of the applications of lasers for major restorative dental procedures and conventional clinical approaches. A remarkable increase in the use of lasers for dental application is expected in the near future.

Agenesis of maxillary lateral incisor in an Angle Class II, Division 1 malocclusion patient.

The present case report describes the orthodontic treatment of a patient with agenesis of maxillary left lateral incisor and Angle Class II, Division 1 malocclusion. The patient also presented with maxillary midline deviation and inclination of the occlusal plane in the anterior region. Treatment objectives were: correction of sagittal relationship between the maxilla and the mandible; correction of midline deviation, so as to cause maxillary and mandibular midlines to coincide; correction of overbite and leveling of the occlusal plane, so as to create ideal conditions for esthetic rehabilitation of anterior teeth. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) as a requirement for the title of certified by the BBO.

Agenesis of maxillary lateral incisor in an Angle Class II, Division 1 malocclusion patient

The present case report describes the orthodontic treatment of a patient with agenesis of maxillary left lateral incisor and Angle Class II, Division 1 malocclusion. The patient also presented with maxillary midline deviation and inclination of the occlusal plane in the anterior region. Treatment objectives were: correction of sagittal relationship between the maxilla and the mandible; correction of midline deviation, so as to cause maxillary and mandibular midlines to coincide; correction of overbite and leveling of the occlusal plane, so as to create ideal conditions for esthetic rehabilitation of anterior teeth. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) as a requirement for the title of certified by the BBO.

O presente caso clínico relata o tratamento ortodôntico de um paciente portador de agenesia do incisivo lateral superior esquerdo e má oclusão de Classe II 1a divisão de Angle. Apresentava, ainda, desvio da linha média superior e inclinação do plano oclusal na região anterior. Os objetivos do tratamento foram adequar a relação sagital entre as arcadas, proporcionar a coincidência entre as linhas médias superior e inferior, corrigir a sobremordida e nivelar o plano oclusal, criando condições apropriadas para a reabilitação estética dos dentes anteriores. Este caso foi apresentado à Diretoria do Board Brasileiro de Ortodontia e Ortopedia Facial (BBO) como parte dos requisitos para a obtenção do título de Diplomado pelo BBO.

Uso de prótese dentária e sua relação com lesões bucais / Use of dental prostheses and their relationship with oral lesions / Uso de prótesis dentales y su relación con lesiones orales

Objetivo Mostrar a relação da prótese dentária com a incidência e o tipo de lesões bucais desenvolvidos na região do Seridó, estado do Rio Grande do Norte, Brasil. Método Foi realizado um cadastro de 77 pacientes, todos com mais de 21 anos de idade, ambos os gêneros, não etilistas e/ou tabagistas crônicos, residentes nos municípios correspondentes a região do Seridó, que apresentavam algum tipo de lesão bucal e que deram entrada nas Clínicas Odontológicas da Universidade do Rio Grande do Norte, sendo observado a relação destas com o uso de próteses dentárias. Resultados A maioria das próteses relacionadas com lesões orais possuía mais de 05 anos de uso e indicação de troca, e que a Candidose, com 45,5 % dos casos e Hiperplasia fibrosa inflamatória, com 27,2 % foram às lesões mais relacionadas. Conclusões As próteses dentárias totais e parciais removíveis apresentaram relação com lesões orais, no entanto, a prótese total apresentou maior percentual de peças indicadas para troca e com mais de 05 anos de uso; mostrando que o tipo parcial removível a grampo mesmo sem indicações de troca, apresentaram uma alta relação com lesões.(AU)

Objective To show the relationship between dental prostheses and the incidence and type of oral lesions developed in the Seridó region of Brazil. Methods 77 patients were registered. All were over 21 years of age, of both sexes, non-alcoholic and / or chronic smokers, and residents of the municipalities of the region corresponding to Seridó. They also all had some type of oral lesion and had been admitted to dental clinics of the University of Rio Grande do Norte. Here, the relationship between these lesions and the dental prostheses that they used was observed. Results The majority of dental prostheses related to oral lesions had more than 5 years of use and required changing. Candidiasis (45.5 %) and inflammatory fibrous hyperplasia (27.2 %) were the lesions most related to the dental prostheses. Conclusions Complete prostheses and removable partial dentures correlated with oral lesions. However, the complete prostheses had a higher percentage ready for change-out and had more than 05 years of use. This demonstrates that removable partial dentures, even without the need for exchange, showed a high correlation with the oral lesions.(AU)

Objetivo Mostrar la relación de prótesis dentales con la incidencia y el tipo de lesiones orales desarrollados en la región Seridó, estado de Rio Grande do Norte, Brasil. Método Se realizó un registro de 77 pacientes. Todos eran mayores de 21 años de edad, de ambos sexos, no alcohólicos y/o fumadores crónicos, residentes de los condados correspondientes a la región Seridó, que tenía algún tipo de lesión oral y que fueron admitidos a clínicas dentales de la Universidad de Río Grande del Norte. Allí se observó la relación de estas lesiones con el uso de las prótesis dentales. Resultados En la mayoría de los casos de lesiones orales, estaban relacionadas prótesis que tenían más de 5 años de uso y requerían ser cambiadas. La candidiasis, con el 45,5 % de los casos, y la hiperplasia fibrosa inflamatoria, con el 27,2 %, fueron las lesiones más relacionadas. Conclusiones Se concluye que las prótesis completas y las prótesis parciales removibles mostraron una relación con lesiones orales. Sin embargo, las prótesis completas tuvieron un mayor porcentaje para ser cambiadas y con más de 5 años de uso. Esto demuestra que el tipo parcial removible, incluso sin necesidad de cambio, mostraron una alta correlación con las lesiones.(AU)

El nacimiento de la higiene dental y los dientes de Waterloo / No disponible

No disponible

Evaluation of selected speech parameters after prosthesis supply in patients with maxillary or mandibular defects.

BACKGROUND: Ablative surgery of oropharyngeal tumors frequently leads to defects in the speech organs, resulting in impairment of speech up to the point of unintelligibility. The aim of the present study was the assessment of selected parameters of speech with and without resection prostheses. PATIENTS AND METHODS: The speech sounds of 22 patients suffering from maxillary and mandibular defects were recorded using a digital audio tape (DAT) recorder with and without resection prostheses. Evaluation of the resonance and the production of the sounds /s/, /sch/, and /ch/ was performed by 2 experienced speech therapists. Additionally, the patients completed a non-standardized questionnaire containing a linguistic self-assessment. RESULTS: After prosthesis supply, the number of patients with rhinophonia aperta decreased from 7 to 2 while the number of patients with intelligible speech increased from 2 to 20. Correct production of the sounds /s/, /sch/, and /ch/ increased from 2 to 13 patients. A significant improvement of the evaluated parameters could be observed only in patients with maxillary defects. The linguistic self-assessment showed a higher satisfaction in patients with maxillary defects. CONCLUSION: In patients with maxillary defects due to ablative tumor surgery, an increase in speech performance and intelligibility is possible by supplying resection prostheses.

Load-bearing capacity of indirect inlay-retained fixed dental prostheses made of particulate filler composite alone or reinforced with E-glass fibers impregnated with various monomers.

The load-bearing capacity and failure types of indirect inlay-retained fixed dental prostheses (FDP), made of particulate filler composite (PFC) (Estenia) alone or reinforced with E-glass fibers impregnated with various monomers were evaluated. Indirect inlay-retained FDPs were made between first premolars and first molars (N=30, 10/per group). The inlay parts of the specimens were silica coated and silanized and the specimens were cemented with dual-polymerized resin cement under ultrasonic vibrations. The experimental groups were as follows: Group 1: FRC1 (BR-100, UTMA) + PFC; Group 2: FRC2 (everStick C&B, Bis-GMA/PMMA) + PFC; Group 3: PFC only. The specimens were kept in distilled water at 37 °C for one month and then subjected to fracture strength test. No significant difference was found between the Group 1 and Group 2 FDPs (1357±301 N and 1213±316 N, respectively) (p>0.05) (ANOVA). Group 3 (856±299 N) showed significantly lower results than those of FRC reinforced groups (p<0.05). Failure analyses revealed no debonding of any of the FDPs from the inlay cavities. FDPs made of PFC only showed mainly catastrophic fracture of the pontic. In the FRC reinforced groups, predominantly delamination of the veneering was observed. The use of silica coating and silanization in combination with the dual-polymerized resin cement used; under ultrasonic cementation procedure provided sufficient adhesion to withstand static loading forces at the cementation interface, since the failures were predominantly delamination of the veneering in the FRC reinforced groups.

Estudo da soldagem a laser em próteses odontológicas / Laser welding dental prosthesis abstract

O objetivo deste trabalho é apresentar uma revisão de literatura sobre a soldagem a laser em próteses odontológicas. A soldagem a lase passou a ser utilizada na odontologia para a confecção de próteses fixas a partir da década de 70...

Avaliação da precisão do articulador semiajustável a7fix / Evaluation of the accuracy of semi-adjustable articulator a7fix

Um dos erros mais frequentes em reabilitação oral é a montagem incorreta dos modelos de gesso no articulador. Os modelos de estudo e, principalmente, os modelos de trabalho, devem ser rigorosamente posicionados numa relação funcional no articulador, que irá representar a maxila e a mandíbula com a articulação temporomandibular e os movimentos mandibulares. O objetivo deste trabalho foi avaliar através de um estudo laboratorial a precisão do articulador A7 Fix Bio-Art padronizado, quando simuladores dos modelos são transferidos de um articulador para outro. Para a realização desta pesquisa foram selecionados dez articuladores e desses, um foi designado como articulador mestre. Foram confeccionadas peças que representassem as duas arcadas e essas foram montadas no articulador mestre e transferidos para os outros nove articuladores e avaliado na transferência os seguintes critérios: efetividade do contato com o carbono (avaliação vertical), coincidência dos parafusos com os orifícios (avaliação horizontal), e coincidência do pino incisal com a linha cheia (avaliação vertical). Os resultados encontrados foram de que em todas as transferências os três parafusos do modelo superior coincidiram com as concavidades realizadas no modelo inferior; a relação de contato interoclusal permaneceu em todas as transferências; somente em dois articuladores houve 1 mm de discrepância em relação a linha cheia. Conclui-se que o articulador A7 Fix (Bio-Art) padronizado permitiu o intercâmbio dos modelos de gesso entre os articuladores.

One of the most usual mistakes in oral rehabilitation is the incorrect assemblage of the cast models on the articulating device. The study models and mainly the work models must be strictly placed to a functional relation on the articulator, which will represent the maxilla and the mandible, with the temporomandibular articulation and the mandible movements. This work aims at evaluating, through a laboratorial experimental study, the accuracy of the 7 Fix Bio-Art standardized when the simulators of the models are transferred from one articulator to another. Ten articulators were selected for this study and one of them was chosen as the master articulator. Parts representing the two articulators were manufactured and assembled on the master articulator and transferred to other nine articulators and in the transference the following criterion were evaluated: effectiveness of the contact with the carbon (vertical evaluation), coincidence of the screws with the holes (horizontal evaluation), and coincidence of the incisal pin with the full line (vertical evaluation) the results found at the end of the test were: in all transference of the three screws of the superior model fit the concavities in the inferior model; the relation of the interoclusal contact happened in the proper way in all transference; only in two of the articulators there was a difference of 1 mm in relation to the full line. It was concluded that the standardization of the A7 FIX (Bio-Art) allowed the interchange of the models among the articulators’ devices.

Cavity preparation machine for the standardization of in vitro preparations.

Several in vitro studies employ the confection of cavity preparations that are difficult to standardize by means of manual high speed handpieces. This study presents the development of a cavity preparation machine designed to standardize in vitro cavity preparations. A metal base of 25 mm x 25 mm x 4 mm (length x width x height) was coupled to a small mobile table which was designed to be able to move by means of two precision micrometers (0.01-mm accuracy) in the horizontal directions (right-left, and back-front). A high speed handpiece was coupled to a metallic connecting rod which had an accurate dial indicator enabling control of the vertical movement. The high speed handpiece is also able to move 180 degrees around its longitudinal axis and 360 degrees around its transversal axis. The suggested cavity preparation machine precisely helps in the standardization of cavity preparations for in vitro studies.