Dentist-laboratory communication and quality assessment of removable prostheses in Oregon: A cross-sectional pilot study.

STATEMENT OF PROBLEM: When fabricating a removable dental prosthesis, it is unclear if the information received by the dental laboratory technician is clear and sufficient. PURPOSE: The purpose of this survey study was to evaluate the dentist's work authorizations for removable prostheses as well as determine common practices used by laboratories during the fabrication of removable prostheses. MATERIAL AND METHODS: A 24-item questionnaire was developed based on previously published questionnaires and incorporating new topics. A public uniform resource locator (URL) survey link was generated and sent to the office of the Oregon Association of Dental Laboratories (OADL). The executive director of the board then sent out the link to 163 participants that included members and nonmembers of the OADL who were still active in the state of Oregon. Two reminder e-mails were sent 2 weeks apart. Study data were collected and managed by using the Research Electronic Data Capture (REDCap) software program. Descriptive statistics were tabulated, and responses displayed as a percentage of the total. RESULTS: From the 163 invited participants, 26 responded to the survey representing a 15.9% response rate. Only 11% of the laboratories stated that they routinely receive work authorizations with clear instructions. All participants stated that they always (62.5%) or frequently (37.5%) design the partial prostheses frameworks. Only 37.5% of the laboratories stated that they usually receive adequately extended and accurate definitive casts to fabricate the framework. Fifty percent of the laboratories stated that they very rarely perform altered cast procedures and 50% indicated that half or more of the removable partial prostheses they fabricate were entirely made of acrylic resin. Most laboratories stated that thermoplastic resin partial dentures were less than 25% of their produced volume of removable prostheses. Only 22% of respondents stated that they usually receive adequate information to complete a denture tooth arrangement and most (78%) dentists do not routinely specify the type of occlusal scheme desired for their complete denture tooth arrangements. In most prostheses (77%), posterior palatal seal was marked by the prescribing dentists rarely or very rarely. CONCLUSIONS: Work authorizations provided by the dentists were less than adequate and left much decision-making to the dental laboratory technician.

Use of Digital Technology to Improve Objective and Reliable Assessment in Dental Student Simulation Laboratories.

The aim of this study was to assess inter-and intra-grader agreement with the use of digital scanning and a tooth preparation assessment software program in comparison to the current traditional visual grading method in a dental student simulation laboratory. Students' typodont teeth preparations from previous practical examinations were used (cast crown n=50; cast fixed partial denture abutments n=50). Five preclinical instructors received calibration training and evaluated each of the preparations by the traditional visual grading method using a rubric. The same preparations were assessed by the same instructors using a tooth preparation assessment software program (PrepCheck, Sirona). The results showed that intra-grader agreement was significantly higher when grades were determined by PrepCheck compared to the traditional visual grading method. The traditional method was associated with significantly greater inter-grader disagreement in comparison to grading using PrepCheck (p<0.05). When the average final grade for students' crown preparations by each grader was compared for the traditional method and PrepCheck, significant differences were found for all graders (p<0.001). In this study, the use of the PrepCheck software program greatly improved intra-and inter-grader agreement during grading in a student simulation laboratory. Digital technology may improve the objectivity and reliability of assessments by preclinical evaluators.

Laboratorio mecánico dental: norma técnica No. 24-2019 / Dental mechanical laboratory: technical standard No. 24-2019

Este documento tiene como objeto: "la regulación, autorización y control de los laboratorios mecánicos dentales, en concordancia con el Reglamento para la Regulación, Autorización, Acreditación y Control de Establecimientos de Atención para la Salud, Acuerdo Gubernativo 376-2007." Es de carácter obligatorio, por lo que se aplica tanto al sector público, privado, social o subsector de la seguridad social, en todo el territorio nacional. Contiene además, las definiciones de los conceptos relacionados al tema principal, además de la infraestructura que deberá tener cada clínica, incluidos el equipo y recurso humano y técnico.

The quality of fixed prosthodontic impressions: An assessment of crown and bridge impressions received at commercial laboratories.

BACKGROUND: The authors evaluated and quantified clinically detectable errors commonly seen in impressions sent to commercial laboratories and determined possible relationships between finish line errors and other factors involved. METHODS: The authors visited 3 large and 1 small commercial dental laboratories over a 12-month period. Three calibrated examiners evaluated the impressions. The examiners evaluated all impressions for errors by using ×2.5 magnification loupes under ambient room lighting without the aid of additional illumination. RESULTS: The authors evaluated 1,157 impressions; 86% of the examined impressions had at least 1 detectable error, and 55% of the noted errors were critical errors pertaining to the finish line. The largest single error categories evaluated were tissue over the finish line (49.09%), lack of unprepared stops in dual-arch impressions (25.63%), pressure of the tray on the soft tissue (25.06%), and void at the finish line (24.38%). The factors blood on the impression (odds ratio, 2.31; P < .001) and tray type (odds ratio, 1.68; P < .001) were associated significantly with finish line errors. CONCLUSIONS: Marginal discrepancies made up the largest category of error noted in impressions evaluated. The authors noted an increase in errors at the finish line with dual-arch impression techniques and in the presence of blood. PRACTICAL IMPLICATIONS: Dentists have ethical, moral, and legal obligations bestowed on them by the profession and need to evaluate critically the work they send to laboratories. The authors strongly recommend an improvement in technique and reviewing of all impressions and working casts.

Understanding dental CAD/CAM for restorations--dental milling machines from a mechanical engineering viewpoint. Part B: labside milling machines.

Nowadays, dental numerical controlled (NC) milling machines are available for dental laboratories (labside solution) and dental production centers. This article provides a mechanical engineering approach to NC milling machines to help dental technicians understand the involvement of technology in digital dentistry practice. The technical and economic criteria are described for four labside and two production center dental NC milling machines available on the market. The technical criteria are focused on the capacities of the embedded technologies of milling machines to mill prosthetic materials and various restoration shapes. The economic criteria are focused on investment cost and interoperability with third-party software. The clinical relevance of the technology is discussed through the accuracy and integrity of the restoration. It can be asserted that dental production center milling machines offer a wider range of materials and types of restoration shapes than labside solutions, while labside solutions offer a wider range than chairside solutions. The accuracy and integrity of restorations may be improved as a function of the embedded technologies provided. However, the more complex the technical solutions available, the more skilled the user must be. Investment cost and interoperability with third-party software increase according to the quality of the embedded technologies implemented. Each private dental practice may decide which fabrication option to use depending on the scope of the practice.

Standards, Regulation and Registration of Dental Laboratories. An Industry Update.

State dental associations are showing increased interest in maintaining current standards and regulations affecting the dental laboratory industry as mandated by the Food and Drug Administration. The domestic dental laboratory industry is being significantly stressed by foreign competition, rapid technology development and unprecedented consolidation, which are changing the way that prosthetic devices and restorations are manufactured and delivered to dentists. Of paramount importance to the prescribing dentist is the accurate documentation of the source and materials being used in prostheses being delivered to patients.

Digital casts in orthodontics: a comparison of 4 software systems.

INTRODUCTION: The introduction of digital cast models is inevitable in the otherwise digitized everyday life of orthodontics. The introduction of this new technology, however, is not straightforward, and selecting an appropriate system can be difficult. The aim of the study was to compare 4 orthodontic digital software systems regarding service, features, and usability. METHODS: Information regarding service offered by the companies was obtained from questionnaires and Web sites. The features of each software system were collected by exploring the user manuals and the software programs. Replicas of pretreatment casts were sent to Cadent (OrthoCAD; Cadent, Carlstadt, NJ), OthoLab (O3DM; OrthoLab, Poznan, Poland), OrthoProof (DigiModel; OrthoProof, Nieuwegein, The Netherlands), and 3Shape (OrthoAnalyzer; 3Shape, Copenhagen, Denmark). The usability of the programs was assessed by experts in interaction design and usability using the "enhanced cognitive walkthrough" method: 4 tasks were defined and performed by a group of domain experts while they were observed by usability experts. RESULTS: The services provided by the companies were similar. Regarding the features, all 4 systems were able to perform basic measurements; however, not all provided the peer assessment rating index or the American Board of Orthodontics analysis, simulation of the treatment with braces, or digital articulation of the casts. All systems demonstrated weaknesses in usability. However, OrthoCAD and 03DM were considered to be easier to learn for first-time users. CONCLUSIONS: In general, the usability of these programs was poor and needs to be further developed. Hands-on training supervised by the program experts is recommended for beginners.

Implementation of new technologies in U.S. dental school curricula.

With dentistry rapidly evolving as new technologies are developed, this study aimed to identify the penetration of emerging dental technologies into the curricula of U.S. dental schools and to explore whether certain school characteristics affected adoption of these technologies. A 19-question survey was sent to the academic deans of all 62 U.S. dental schools. In addition to questions about characteristics of the school, the survey asked respondents to indicate where in their curricula the technology was incorporated: preclinical didactic, preclinical laboratory, clinical didactic, and/or clinical patient experience. Of 62 eligible schools, 33 useable responses were received, for a 52% response rate. The results showed that the greatest overall penetration of dental technologies was in preclinical didactic courses and the lowest was in the preclinical laboratory. Specific technologies implemented in the largest percentage of responding schools were digital radiography and rotary endodontics. The technologies with the lowest penetration were CAD/CAM denture fabrication and hard tissue lasers. These results suggest that the incorporation of technology into dental schools is following that of private practice as the most widely adopted technologies were those with the greatest acceptance and use in private practice. Among the respondents, factors such as class size and age of the school had greater impact on incorporation of technology than funding source and geographic location.

Curriculum time compared to clinical procedures in amalgam and composite posterior restorations in U.S. dental schools: a preliminary study.

Dental clinicians have an expanding range of biomaterial choices for restoring tooth structure. Scientific developments in cariology, advances in dental biomaterials, and patients' esthetic concerns have led to a reduction in amalgam restorations and an increase in composite restorations. The aim of this study was to compare teaching time with students' clinical procedures in amalgam and composite posterior restorations in dental schools across the United States. Academic deans in 60 schools were invited to complete a survey that asked for the amount of instructional time for amalgam and composite posterior restorations and the number of clinical restorations performed by their Classes of 2009, 2010, and 2011. Of these 60, 12 returned surveys with complete data, for a 20% response rate. Responses from these schools showed little change in lecture and preclinical laboratory instruction from 2009 to 2011. There was a slight increase in two-surface restorations for both amalgam and composites; however, the total number of reported composite and amalgam restorations remained the same. Of 204,864 restorations reported, 53% were composite, and 47% were amalgam. There were twice as many multisurface large or complex amalgam restorations as composites. One-surface composite restorations exceeded amalgams. Among the participating schools, there was little to no change between curriculum time and clinical procedures. Findings from this preliminary study reflect a modest increase in two-surface resin-based restorations placed by dental students from 2009 to 2011 and little change in curricular time devoted to teaching amalgam restorations. The total number of posterior composite restorations placed by students in these schools was slightly higher than amalgams.

A laboratory assessment of bacterial leakage in MTA apical plugs exposed to phosphate-buffered saline / Avaliação laboratorial da infiltração bacteriana em plugs apicais de mta expostos ao tampão fosfato-salino

O presente estudo avaliou a influência da exposição do agregado de trióxido mineral (MTA) – com e sem cloreto decálcio (CaCl2) – ao tampão fosfato-salino (PBS) sobre a microinfiltração apical. Sessenta segmentos radiculares foram divididos em 4 grupos experimentais (n=15). As cavidades apicais foram preenchidas com MTA, com ou sem CaCl2, e os canais radiculares receberam uma bolinha de algodão umedecida ou PBS, como medicação intracanal: 1) MTA/bolinha de algodão umedecida; 2) MTA/PBS; 3) MTA+10%CaCl2/ bolinha de algodão umedecida; 4) MTA+10% CaCl2/PBS. Após 2 meses, a penetração de E. faecalis ao longo dos plugs apicais foi avaliada. As amostras foram observadas semanal -mente durante 70 dias e a infiltração detectada através da turbidez do meio em contato com os segmentos radiculares. Dentes pertencentes aos grupos controle (n=2) foram mantidos completamente impermeáveis ou sem plug apical. A análise de sobrevivência e a comparação das curvas foram realizadas por meio dos testes Kaplan-Meier e Log-rank (p<0.05), respectiva -mente. Todas as amostras do grupo controle positivo apresentaram evidência de infiltração dentro de 24h, enquanto nenhuma amostra do grupo controle negativo apresentou infiltração aolongo dos 70 dias. Não houve diferença significativa entre os grupos experimentais (p=0.102). O uso do PBS como medicação intracanal pode melhorar a capacidade de selamento do MTA,mas não é capaz de impedir a infiltração bacteriana. A adição de CaCl2 ao MTA não melhora sua capacidade de selamento.

This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride(CaCl2) -to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2months, E. faecalis penetration was analyzed a long the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made completely impermeable or kept without an apical plug. The Kaplan–Meier method was used to analyze survival and the Log-rank test was used to compare the survival curves (p<0.05). All specimens in the positive control group showed evidence of leakage within 24h, while none in the negative control group showed leakage up to 70 days. There was no statisticall y significant difference among the experimental groups (p=0.102).The use of PBS as intracanal dressing may improve MTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.

Dental technology services and industry trends in New Zealand from 2010 to 2012.

OBJECTIVE: To provide a snapshot of the New Zealand dental technology industry and influencing factors. BACKGROUND: Developing an understanding of the commercial dental laboratory environment in New Zealand can provide insight into the entire dental industry. METHODS: A web-based survey was the primary method for data collection, with separate questionnaires used for dental laboratory owners and dental technician employees. RESULTS: The mean net income for dental laboratory owners in New Zealand was similar to that of the United Kingdom, at $40.50 per hour. Clinical dental technicians are the highest paid employees, with a mean of $33.49 per hour. The mean technical charge for complete dentures was $632.59; including clinical services, it was $1907.00. The mean charge for a porcelain-fused-to-metal (PFM) crown was $290.27. Dental laboratory owners expressed fear about the possibility of losing dental clients to overseas laboratories due to the availability and cheap charge of offshore work. Only 25.4% of dental laboratories surveyed had computer-aided design (CAD) facilities, and even fewer (7.9%) had computer-aided manufacturing (CAM) systems. CONCLUSION: Clinical dental technology appears to be prospering. The dental technology industry appears to be adapting and remains viable, despite facing many challenges.

Complete digital workflow for the production of implant-supported single-unit monolithic crowns.

OBJECTIVES: The aim of this case series was to introduce a complete digital workflow for the production of monolithic implant crowns. MATERIAL AND METHODS: Six patients were treated with implant-supported crowns made of resin nano ceramic (RNC). Starting with an intraoral optical scan (IOS), and following a CAD/CAM process, the monolithic crowns were bonded either to a novel prefabricated titanium abutment base (group A) or to a CAD/CAM-generated individualized titanium abutment (group B) in premolar or molar sites on a soft tissue level dental implant. Economic analyses included clinical and laboratory steps. An esthetic evaluation was performed to compare the two abutment-crown combinations. RESULTS: None of the digitally constructed RNC crowns required any clinical adaptation. Overall mean work time calculations revealed obvious differences for group A (65.3 min) compared with group B (86.5 min). Esthetic analysis demonstrated a more favorable outcome for the prefabricated bonding bases. CONCLUSIONS: Prefabricated or individualized abutments on monolithic RNC crowns using CAD/CAM technology in a model-free workflow seem to provide a feasible and streamlined treatment approach for single-edentulous space rehabilitation in the posterior region. However, RNC as full-contour material has to be considered experimental, and further large-scale clinical investigations with long-term follow-up observation are necessary.

The quality of impressions for crowns and bridges: an assessment of the work received at three commercial dental laboratories. assessing qualities of impressions that may lead to occlusal discrepancies with indirect restorations.

There are few published studies that directly assess the quality of impressions for crowns and bridges in the UK. This paper considers aspects of impression quality with particular attention to factors causing potential occlusal discrepancies in the final restoration. To this end three dental laboratories were visited over a 3-month period. All impressions for conventional crown and bridgework that arrived on the days of the visits were examined and assessed against criteria defined on a custom-designed assessment form. A total of 206 impression cases were considered in this study. Flexible impression trays were used for 65% of working impressions. Their use was more common for NHS work than for private work. 31.9% of all alginate impressions examined were not adequately fixed to the tray. Visible contamination of impressions was not uncommon.