How LEAN Manufacturing Principles Can Help Dental Laboratories

Laura Andreescu, MBA, CDT

August 2022 Issue - Expires Sunday, August 31st, 2025

Inside Dental Technology

Abstract

When planning a transition from analog to digital processes via CAD/CAM systems, dental laboratories must choose business strategies that will maximize their production efficiency and increase the quality of their products and services to meet the expectations of the dental care team. This article reviews how laboratories can apply LEAN manufacturing principles in selecting and implementing new processes, while also maintaining production efficiency. These principles were developed to control unnecessary manufacturing waste, apply supply and demand principles, and eliminate production errors through better time management and quicker implementation of innovative methods of manufacturing. LEAN manufacturing principles can be used in the dental laboratory to adopt new technology that allows the business to remain competitive, provide enhanced standards of care, and develop core competencies geared toward business growth.

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The rapid development of digital technology has greatly impacted the future of the dental industry, and that has only intensified with the introduction and implementation of computer-aided design/computer-aided manufacturing (CAD/CAM) systems. Today, with so many diverse options available, dental laboratories often find themselves in a quandary when choosing which types of dental technology, equipment, and materials to implement in order to stimulate business growth.

One of the main dilemmas with which dental laboratories are confronted is determining which digital dental technology or CAD/CAM system is better for their business model. Another question is whether they should shift to fully digital or intertwine new technology with existing hands-on or traditional manufacturing processes. Additionally, the transition period from traditional production methods to a new business path can impact the laboratories' resources and revenues. To resolve these issues, laboratories must choose business strategies that will maximize their production efficiency and increase quality of products and services to meet the expectations of the dental care team.

One way to sort through the large variety of available digital dental products is to identify the business model that best fits the laboratory's scope and analyze how quickly the CAD/CAM systems can be assimilated into the production workflow. This analysis can be conducted by applying LEAN manufacturing principles to select and employ the right system. These sets of manufacturing principles were first developed in the 1930s by the Japanese company Toyota and used to improve the efficiency of the Toyota Production System by controlling unnecessary manufacturing waste, applying supply and demand principles, and eliminating production errors through better time management and quicker implementation of innovative methods of manufacturing.

This article reviews how dental laboratories can apply LEAN manufacturing principles in selecting and implementing new processes, while also maintaining production efficiency. During the transition from analog to digital manufacturing processes via CAD/CAM systems, it is imperative to continue delivering high-quality dental products and services to the dental care team and promoting the health and well-being of dental patients.

The Benefits of Transition

The implementation of CAD/CAM systems in the dental field is beneficial to dental practitioners, laboratories, and patients because of improved and consistent quality for dental products and services, faster manufacturing processes, and shorter delivery time, leading to fewer patient visits.1,2 For instance, dental implant planning software for guided surgery not only can assist in the detection of the ideal implant placement, but also can provide information on how the treatment is progressing during all stages, from the clinical to the restorative aspect.

A recent article describes the importance of dental implant planning, starting with the radiographic examination and concluding with the success of the restoration: "The ideal dental implant treatment plan will create a blueprint to achieve the best possible biological, functional, and esthetic outcomes for each individual patient, while ensuring long-lasting results. Successful outcomes depend on the clinician performing all steps throughout planning and therapy with careful consideration of the final restorative/prosthetic goals. By combining the radiographic examination with the prosthetic plan, surgical guides may be used to enhance the accuracy of implant placement while maintaining the constraints of 3D implant positioning guidelines."3

During the transition period from analog to digital manufacturing processes, many dental laboratories still utilize both methods as separate workflows for fabricating prostheses, which can negatively impact their business practices. Maintaining two separate workflows increases the financial burden on the laboratory due to the capital investment into different systems, equipment, and materials. More resources are wasted through investment in products that will not add value to the production process. Furthermore, it makes it difficult to monitor the efficiency of the workflows, and reduces resources for continuous improvement of the manufacturing processes.

The Five Principles

At the core of LEAN manufacturing are five principles that are used to increase production efficiency. The first principle is value, and implementation begins with defining the value of the products and services for which customers are willing to pay. Next, the business must reduce or eliminate products that are not meeting these requirements. Then, the value can be further divided into value-adding processes, which create a product or service that is profitable, and non-value-adding processes, which include all the activities that are not generating revenue/profit, such as repair activities, overproduction, etc. Non-value-adding processes are considered waste, and should be minimized wherever possible.4

The second principle focuses on mapping the value stream. Begin by identifying each production stage and analyzing the efficiency of each of those stages, then work to eliminate the activities that are not adding value (See Table 1 at insidedentaltech.com/idt1310).

The third principle relates to creating flow and ensuring that there is a smooth transition from one stage of production to another by eliminating bottleneck situations through monitoring the progression of each task. LEAN manufacturing principles aim to create continuous and seamless flow through reduction in variation of demand and standardization of processes.5

The fourth principle is to establish pull by manufacturing products that are in demand. This principle is intended to ensure that supply doesn't outstrip demand, resulting in waste. For dental laboratories, this principle is inherently applied with every case due to the high level of customization in this work and the fact that each prosthesis is only fabricated when the patient needs it.

The fifth principle is to pursue perfection, indicating that manufacturing processes should be constantly improved for greater efficiency by increasing or maintaining quality of products and reducing production waste and costs. This is a continuous process "since the potential for further improvements in business operations always exists and a complete perfection state can never really be reached."6

Dental laboratories can choose different approaches to select what business model is best for them, but it is important to begin with a clear vision of their scope. To start the process of implementing digital technologies and workflows, dental laboratories must narrow down their options by asking themselves the following questions:

1. What are we trying to accomplish?

2. How will we know that a change is an improvement?

3. What change can we make that will result in an improvement?

Donald M. Berwick, the author of these questions, imparts great wisdom in the following two statements: "Not all change is improvement, but all improvement is change," and "Concentrate on meeting the needs of patients rather than the needs of organizations."7 When answering these questions, dental laboratories should consider the implications outlined below.

What Are We Trying to Accomplish?

Each dental laboratory must adopt a business model that is customized to its needs and expertise. However, it is more important to understand who its customers are, their demands, and how their requirements can be transferred into products that add value to the laboratory's business. Feedback from the dental care team is very valuable and allows dental laboratories to analyze what dentists need to best treat their patients. The direct contact between dentists and patients permits dentists to communicate the necessities for a successful outcome.8 For instance, when developing a business model, each dental laboratory can conduct a survey among its customers/dental practices to see if the selected model will generate interest, and then they can estimate the potential for growth. In this way, the laboratory can determine the best choice for a business model and establish the goals they would like to accomplish.

How Will We Know That a Change Is an Improvement?

Measurement is the only way of knowing how the implementation of CAD/CAM systems will benefit the business. Thus, it is important to complete a break-even analysis, where the value added to the business is evaluated against the capital and human resources investment.9

Given the complexity of products and services that dental laboratories provide, a break-even analysis must be conducted for each manufacturing process, after which the data across all processes can be combined into an overall evaluation. The purpose of this is to find the break-even point where the expenses are matched by profit, determine the time it will take for the business to get to the break-even point, and identify how the manufacturing processes can be optimized to increase revenue. With the results of this analysis, it is possible to tell whether a proposed change will actually be an improvement or whether the potential investment costs outweigh the benefits.

What Change Can We Make That Will Result in an Improvement?

Factors that influence production improvement are total production cost, manufacturing cycle time, and quality of products and services. The total production costs can be divided into two categories: fixed costs (rent, insurance, taxes, etc) and variable costs (production supplies, wages, delivery services, etc). These expenses should be covered by the production output and sales growth. If there is no increase in output and sales, then the project is not economically effective.10

The manufacturing cycle time refers to how long it takes to complete an order, and generally encompasses four major components: process time, during which the product is manufactured; move time, during which the product is moved from one production stage to the next; inspection time, during which quality control takes place; and waiting time, during which the product is prepared for delivery.11,12

The third factor, quality of products and services, is largely self-explanatory. If the new processes do not create at least an equal—or ideally, a superior—product or service, then the change is not resulting in an improvement.

In addition to the questions above, dental laboratories must perform an analysis to mitigate the risks associated with the implementation of new digital technologies:

• What is the existing workflow, and how can new processes be integrated into production?

• What are the new resources necessary to integrate the new technologies?

• Is there a demand for these new products, or is the market already saturated by too many similar products?

• Can the supply chain provide continuous supplies to production? Any interruption of supply chain can result in lost value to customers and ultimately lost revenue.

• What are the instruments for monitoring production improvement?

Once laboratories answer these questions, they will have a much clearer vision of how their business should evolve, and the next step will be to find and employ successful strategies for sustaining business growth.

The Five S's

LEAN manufacturing principles can also be applied to integrate new digital strategies through organization and standardization of the manufacturing processes. There are five important strategies, known as "The Five S's," which are designed to control and monitor productivity and reduce waste (See Table 2 at insidedentaltech.com/idt1310).

First Strategy: Sort

Begin by completing a thorough inventory of all the equipment and materials necessary for both analog and CAD/CAM methods. This involves setting aside unused equipment or materials, checking the expiration date for each stored dental material, and taking action to either return them to the manufacturer or exchange them for other products.

Second Strategy: Set in Order

Set a plan in order by analyzing the workflow for both analog and digital manufacturing processes and identifying any gaps in production, including downtime or production inefficiency, for each specific dental appliance. Monitor and evaluate the supply and demand chain based on past production and how many different types of dental prostheses or appliances are fabricated, (eg, how many ceramic vs porcelain-fused-to-metal crown/bridges). This step should be done for each type of dental appliance/prosthesis or service provided by the laboratory. Then select which types of dental prostheses/appliances should still be manufactured with analog methods and which could be transferred to a new CAD/CAM system.

From this point, it is possible to develop new workflows that integrate both analog and digital manufacturing processes, thus adding value by finding the complementary elements of each. Eliminate waste in the workflow by adopting only the CAD/CAM applications that add value to the manufacturing process. For example, if a dental laboratory's production is based on manufacturing only fixed prosthodontics, then it is not necessary to implement software used for manufacturing removable prosthodontics.

Finally, implement CAD/CAM applications that are compatible with each other, which guarantees the transmission of all data from one system to another. For example, using one type of software for the design and then switching to another for manufacturing could create flaws and inefficiencies in the production process.

Third Strategy: Shining

Keep the facility clean and organized and perform regular maintenance on equipment and machinery. Organize all inventory necessary for manufacturing processes, including equipment, software, dental materials, etc. This will increase process efficiency and reduce downtime due to issues like lack of inventory or equipment malfunction.

Fourth Strategy: Standardizing

Establish procedures and production schedules to ensure the repetition of the first three strategies. Develop and maintain the inventory schedule, periodically inspect and clean, and perform ongoing analysis to remove any unnecessary gaps in production/workflow. Adopt the new practice into the daily routine and maintain standard operating procedures. Periodically evaluate process performance and efficiency. Train dental technicians to perform the new workflow and to assure high production efficiency and quality. Ensure that employees know their responsibilities and maintain appropriate production efficiency.

Fifth Strategy: Sustaining

Improve the workflow by researching other applications that will add value to the manufacturing process. Monitor the inventory flows and move it only when needed in the manufacturing process. Perform regular system assessment to ensure that all defined standards are being executed and followed. Adopt improvements whenever possible. Utilize workers' input and feedback to identify production needs. Identify possible system problems and their cause, and implement the changes necessary to avoid recurrences. Apply the two principles of quality assurance: "fit for purpose," which means that the product meets the standards it was designed for, and "right the first time," meaning that any mistake in the production process is dealt with right away, therefore eliminating compounding mistakes.13

Total Quality Management

In addition to "The Five S's," dental laboratories can utilize the total quality management principle, which states that all employees involved in the manufacturing process are responsible and accountable for the overall quality of products and services. After implementing new workflows, dental laboratories must periodically perform evaluations of the manufacturing processes and search for new innovations that will facilitate continuous improvement of production.

Conclusion

Dental laboratories must be innovative in adopting technologies and methodologies to maintain their competitive edge. In addition to remaining competitive, adopting new technology will result in enhanced standards for dental care through the quality of products and services that can be achieved by employing LEAN manufacturing principles to develop core competencies geared toward business growth. Ultimately this results in improved well-being for dental patients.

About the Author

Laura Andreescu, MBA, CDT
Assistant Professor of Restorative Dentistry
New York City College of Technology, CUNY

References

1. Deranek K, Kramer S, Siegel S. Technology-dependent pedagogical process redesign: Leveraging lean methods. Int J Qual Reliab Manag. 2021;38(8):1816-1832. doi:10.1108/ijqrm-04-2020-0107

2. Robinson FG, Cunningham LL, Turner SP, et al. Improving a dental school's clinic operations using lean process improvement. J Dent Educ. 2016;80(10):1170-1179. doi:10.1002/j.0022-0337.2016.80.10.tb06199.x

3. Parra C, Harrel SK. Treatment planning strategies for dental implant procedures. Decisions in Dentistry. https://decisionsindentistry.com/article/strategies-dental-implant-procedures/. Published September 20, 2019. Accessed July 25, 2022.

4. Manzanera R, Moya D, Guilabert M, et al. Quality assurance and patient safety measures: A comparative longitudinal analysis. Int J Environ Res Public Health. 2018;15(8):1568. doi:10.3390/ijerph15081568

5. Pinkney J, Rance S, Benger J, et al. How can frontline expertise and new models of care best contribute to safely reducing avoidable acute admissions? A mixed-methods study of four acute hospitals. Health Serv Res. 2016;4(3):153-158. doi:10.3310/hsdr04030

6. Thangarajoo Y. Lean thinking: An overview. Ind Eng Manag Syst. 2015;04(02). doi:10.4172/2169-0316.1000159

7. Berwick DM. A primer on leading the improvement of systems. BMJ. 1996;312(7031):619-622. doi:10.1136/bmj.312.7031.619

8. Alsyouf I, Al-Aomar R, Al-Hamed H, Qiu X. A framework for assessing the cost effectiveness of lean tools. Eur J Ind Eng. 2011;5(2):170-197. doi:10.1504/ejie.2011.039871

9. Singh MM, Choudhary PK, Patnaik SK, Kaushal G. Break-even analysis in healthcare setup. Int J Res Foundation Hosp Healthc Adm. 2013;1(1):29-32. doi:10.5005/jp-journals-10035-1006

10. Pushina NN, Sokolova NG, Koretskiy VP. Cost efficiency indicators of lean production instruments. Proceedings of the International Scientific Conference "Far East Con" (ISCFEC 2020). 2020. doi:10.2991/aebmr.k.200312.088

11. Deshpande V, Prajapati M. Cycle time reduction using lean principles and techniques: A review. Int J Ind Eng Comput. 2015;3(4):208-213.

12. Kren L, Tyson T. Using cycle time to measure performance and control costs in focused factories. ResearchGate. https://www.researchgate.net/publication/237505449_Using_cycle_
time_to_measure_performance_and_control_costs_in_focused_factories
. Published 2011. Accessed July 25, 2022.

13. Joosten T, Bongers I, Janssen R. Application of lean thinking to health care: Issues and observations. Int J Qual Health Care. 2009;21(5):341-347. doi:10.1093/intqhc/mzp036

An example of mapping the value stream diagram for laboratories.

Table 1: Mapping

An example of application of LEAN principles in a laboratory.

Table 2: The Five S's

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SOURCE: Inside Dental Technology | August 2022

Learning Objectives:

  • Discuss the five principles of LEAN manufacturing and how they can be applied to a laboratory transitioning from analog to digital processes
  • Explain the process for establishing the best business model for a laboratory to pursue during transition periods
  • Describe “The Five S’s” and how these strategies affect laboratory productivity and waste management

Disclosures:

The author reports no conflicts of interest associated with this work.

Queries for the author may be directed to jromano@aegiscomm.com.